Celstran - Hi Polymers

Celstran

®

®

Compel

Celstran

®

Compel

®

Long-fibre-reinforced thermoplastics (LFT)


• markedly higher mechanical properties • high notched impact strength • reduced creep tendency • very good stability over a broad range of temperatures and climatic conditions

Celstran®

Compel®

long-fibre-reinforced thermoplastics (LFT)

Table of Contents 1.

Introduction

4

1.1 1.2 1.3

General information Quality Management Brief description

4 5 5

2.

Grades

7

2.1 2.2 2.3 2.4 2.5

Overview of grades Survey and nomenclature of Celstran Survey and nomenclature of Compel Form supplied Colours

7 8 8 9 9

3.

Material Data

10

4.

Physical Properties

20

4.1 4.2 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.3 4.3.1 4.3.2 4.3.3 4.4 4.5 4.6

General information Mechanical properties Preliminary remarks Short-term stress Creep properties Toughness Fatigue Surface properties Thermal properties Coefficient of expansion Specific heat, enthalpy Thermal conductivity Electrical properties Optical properties Acoustic properties

20 21 21 21 23 25 26 26 27 27 27 28 28 29 29

5.

Environmental Effects

30

5.1 5.1.1 5.1.2 5.2 5.3 5.4

Thermal properties Heat deflection temperature Heat ageing Flammability Chemical resistance Weathering and UV resistance

30 30 30 31 32 32

® = registered trademark

2

Celstran®

Compel®


Introduction

1

Grades

2

Material Data

3

Physical Properties

4

Environmental Effects

5

43 43 43 45

Processing

6

Recycling

46

Finishing

7

9.

Photo supplement showing typical applications

47

10.

Subject Index

51 Recycling

8

11.

Literature

53

Photo supplement showing typical applications

9

6.

Processing

33

6.1 6.2

33 33

6.2.1 6.2.2 6.2.3 6.2.4 6.2.5 6.2.6 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.4 6.5 6.5.1 6.5.2 6.6

Preparation Injection moulding of Celstran including mould making Machine requirements Processing conditions Flow properties and flow path lengths Shrinkage Gate and mould design Special methods Blow moulding of Celstran Materials Machine requirements Parison die Temperatures Extrusion of Celstran Processing of Compel Plasticizing/compression moulding Other methods Safety notes

33 34 36 36 38 38 39 39 40 40 40 41 41 41 42 42

7.

Finishing

43

7.1 7.2 7.2.1 7.2.2

Machining Assembly Welding Adhesive bonding

8.

Subject Index

10

Literature

11

3

Celstran®

Compel®


1. Introduction 1.1 General information Celstran and Compel are long-fibre-reinforced thermoplastics (LFT) made by Ticona. Various processing methods are used to produce high-strength components from these materials, which are tailor-made to customers' requirements (fig. 1.1). Almost all partially crystalline and amorphous thermoplastics are suitable as thermoplastic matrix materials. These grades are produced in a special patented pultrusion process [1]. The fibres incorporated in this process can be glass, carbon, aramid or stainless steel. In pultrusion the continuous filaments are pulled through the thermoplastic melt. Process control and die are optimized so that

Fig. 1.2 · Diagram of a fully impregnated long-fibre pellet (right) compared with wire coating (centre) and short-fibre pellets (left) Ce Co lstran ® mp el ®

Short-fibre pellet

Wire coating

fibre length = 0.2 to 0.4 mm

Fully impregnated long-fibre pellet fibre length = 10 to 25 mm

Fig. 1.3 · Cross-section through a Celstran PP-GF50 pellet, a PP reinforced with 50% by weight long glass fibres

- high impregnation quality without damage to the fibres is achieved and - the individual filament of the reinforcing fibres is thoroughly wetted [1, 2], fig. 1.2 and 1.3. Fig. 1.1 · Celstran and Compel are starting materials for high-strength components

These materials have substantially better mechanical properties than comparable short-fibre-reinforced thermoplastics. The long-fibre-reinforced thermoplastics are thus suitable for the manufacture of mouldings that are subject to high mechanical stress – even at elevated temperatures – and for products that have in the past been made of cast metals or thermosets. The most important field of application at present for Celstran is the automotive sector [3]. For example, gear levers and sunroof drainage channels are made from it because of the mechanical stress imposed on them. Parts near the engine such as fan shrouds, fig. 1.4, engine noise deadening casings, fig. 1.5, or housings for electronic engine control systems, fig. 1.6, also have to withstand additional temperature stress.

4

Celstran®

Compel®


Fig. 1.4 · Fan shroud made from Celstran PP-GF40 for the BMW E38 and E39 diesel vehicles (manufacturer: Geigertechnik GmbH, Garmisch Partenkirchen, Germany)

1.2 Quality Management Celstran is a unit of Ticona, Kelsterbach and is registered to ISO 9001. QS-9000 certification is scheduled until end of 2000.

1

The quality system and the associated documentation are constantly being developed. The basis for this is VDA vol. 6, 4th edition, 1998, QS-9000 and an annual self-assessment in accordance with the criteria model of the European Quality Award (EQA) of the European Foundation of Quality Management.

Fig. 1.5 · Engine noise deadening casing made from Celstran PP-GF40 for the Porsche Boxster (manufacturer: Mürdter, Mutlangen, Germany)

To foster effective partnerships with our customers Ticona offers to conclude quality agreements and also to issue test certificates. These agreements document the specifications for our products. 3.1B certificates in accordance with EN 10 204 can be arranged for each consignment. 1.3 Brief description The most important application properties of the long-fibre-reinforced thermoplastics compared with the corresponding short-fibre-reinforced materials are - markedly higher mechanical properties - higher notched impact strength - reduced creep tendency - very good stability at elevated temperatures in humid conditions.

Fig. 1.6 · Housing made from Celstran PP-GF40 for the electronic engine control system of the Mercedes Benz Roadster “SLK” (manufacturer: Kostal GmbH & Co.KG, Lüdenscheid, Germany)

Celstran is the trademark for long-fibre-reinforced thermoplastics. They are supplied in form of cylindrical moulding granules (typical geometry: diameter 3 mm, length up to 12 mm), in which fibre length and pellet length are identical. The range of Celstran products comprises a number of possible matrix-fibre combinations. They are intended for injection moulding, extrusion and blow moulding and produce moulded parts with markedly greater fibre lengths than conventional short-fibrereinforced plastics. Celstran mouldings display fracture behaviour typical of long-fibre reinforcement. This is demonstrated when the fibre length exceeds a critical value. This value depends on the fibre-matrix combination; practical experience shows that it is between 0.8 and 3 mm. Above this fibre length the material has the characteristics of a fibre composite [1].

5

Celstran®

Compel®


The long-fibre reinforcement is manifested by the fibre skeleton whose outer shape remains unchanged after the resin matrix is burned off, fig. 1.7. This fibre skeleton is responsible among other things for the good impact strength; it absorbs the impact energy and dissipates it in the moulding. The long-fibre reinforcement also has a beneficial effect on the properties at elevated service temperatures and on the creep properties.

Fig. 1.7 · After burning off, a moulding (example: pump head made from Celstran PA66-GF50, top) retains its geometry almost intact as a fibre skeleton (bottom)

Celstran SF grades are masterbatches with 50 to 60% by weight stainless steel filaments [4, 5]. They are used to produce housings with electromagnetic shielding properties and antistatic components, see supplement [4] (will be mailed upon request). Compel is the trademark for even longer pellets (typical length: 25 mm). When processed, they are plasticized gently and then compression-moulded. This gentle process yields higher impact strength and energy absorption than injection moulding, particularly with large-area structural components, fig. 1.8. Processing of Compel by plasticizing/compression moulding offers the following advantages compared with e.g. GMT compression moulding: - freedom of shaping without the use of cut outs - low energy requirement due to screw plasticizing - low moulding pressure required - very good melt flowability - uniform glass fibre content even in thin ribs - good moulded part surfaces - immediate recycling of production waste. For further details of Compel please order our Compel brochure.

6

Fig. 1.8 · Instrument panel carrier for a car made from Compel PP-GF30 by plasticizing / compression moulding

Celstran®

Compel®


2. Grades 2.1 Overview of grades

1 Celstran

Material

Glass fibres

Filaments of stainless high-grade steel

Carbon fibres

Aramid fibres

PP

PP-GF30-04 PP-GF30-05 PP-GF40-04 PP-GF40-05 PP-GF50-04 PP-GF57-05

PP-SF60

PE-HD

PE-HD-GF60-01

PA66

PA66-GF40-01 PA66-GF40-02 PA66-GF50-01 PA66-GF50-02 PA66-GF60-01 PA66-GF60-02

PA66-SF50

PA66-CF40-01

PA66-AF35-02

PA

PA12-SF50

PA6-CF30

ABS

ABS-SF50

PC

PC/ABS-GF25-02 PC/ABS-GF40-02

PC-SF50

PBT, PET

PBT-GF40-01 PBT-GF50-01 PET-GF40-01 PET-GF50-01

PBT-SF50

PPS

PPS-GF50-01 PPS-GF40-01

PPS-SF 50

TPU

TPU-GF30-01 TPU-GF40-01 TPU-GF50-01 TPU-GF60-01

POM

POM-GF40-01

PPS-CF40-01

2

PPS-AF35-01

TPU-CF40-01

POM-SF50

POM-AF30-01

Compel PP

PP-GF30-04 PP-GF30-05 PP-GF40-04 PP-GF40-05 PP-GF50-04 PP-GF57-05

7

Celstran®

Compel®


2.2 Survey and nomenclature of Celstran

Fig. 2.1 · Grade designation for Celstran

In the grade designation for Celstran, fig. 2.1,

Example:

- the first group of symbols indicates the basic polymer - the letters after the hyphen indicate the type of reinforcing fibres - the number immediately following indicates the fibre content in % by weight - the pair of numbers appended after the grade designation (modification) indicate special features as viscosity, impact strength, heat stabilization etc. - the second pair of numbers is an additional suffix for special formulations like high light stabilization, ease of demoulding, markedly low emission rate etc. - P with the following numbers characterise the pellet length and with it the fibre length in mm - the numbers after the dash symbolize the colour code. Natural grades have no declaration.

Matrix material

2.3 Survey and nomenclature of Compel Grades of Compel with polypropylene as matrix material with 30-57% long-glass-fibre reinforcement are currently available. All Compel grades are heat-stabilized.

Celstran PP-GF40-0414P10/10

Type of fibre Fibre content in % (w/w) Modification Additional suffix Pellet length in mm Colour Key to abbreviations: Matrix materials: PP PA66 PA6 PA12 PBT PC PE-HD PET POM PPS TPU ABS

Polypropylene Polyamide 66 Polyamide 6 Polyamide 12 Polybutylene terephthalate Polycarbonate High-density polyethylene Polyethylene terephthalate Polyoxymethylene Polyphenylene sulphide Thermoplastic polyurethane Acrylonitrile-butadiene-styrene

Fibres: GF CF AF SF

Glass Carbon Aramid Stainless steel

Modification of Celstran PP: 03 04

chemically coupled, heat stabilized chemically coupled, heat stabilized, increased flowability chemically coupled, heat stabilized, high impact modificated

05

Modification of Celstran PA: 01 02 10

high gloss heat stabilized flame-retardant (V-0 in accordance with UL 94)

Modification of Celstran PE-HD: 01

chemically coupled

Additional suffix: 16 05 53 55

easily demouldable highly light-stabilized markedly low C emission markedly low C emission and light stabilized

Colours: without 10-19 20-29 30-39 40-49

8

natural black white grey red

50-59 60-69 70-79 80-89 90-99

yellow brown green blue specialities

Celstran®

Compel®


2.4 Form supplied

2.5 Colours

To a large extend Celstran and Compel are supplied to individual requirements both in terms of the thermoplastic matrix and of the fibres used for reinforcement. Possible matrix systems are

Celstran PP and Compel PP are normally supplied in natural and black. In-house coloration by the processor is not recommended because of the need for gentle plasticization.

- high-density polyethylene, PE-HD - polypropylene, PP - polyacetal, POM (Hostaform®) - polybutylene terephthalate, PBT (Celanex®) - polyethylene terephthalate, PET (Impet®) - polyphenylene sulphide, PPS (Fortron®) - thermoplastic polyurethane, TPU - acrylonitrile-butadiene-styrene copolymer, ABS - polycarbonate, PC, and PC blends with ABS - polyamide 66, PA66 - polyamide 6, PA6 - polyamide 12, PA12.

Coloration of Celstran PP and Compel PP is subject to limitations; colours on request. Celstran PA can be supplied coloured.

2

Other matrix systems are being prepared. The following reinforcing fibres are available: - glass - carbon - aramid - stainless steel filaments. Celstran is supplied in 25-kg bags and 500-kg large containers. Silo truck delivery is also possible (à 20 t) with Celstran. Because of the high impregnation of the fibres pneumatic conveyance is possible. Compel is supplied in 20-kg bags and 400-kg large containers.

9

Celstran®

Compel®


3. Material Data Physical property

Unit

Test method

Test specimen

Content of reinforcing material

% by wt.

ISO 3451, part 1

No test specimen (pellets)

Density

g/cm3

ISO 1183

10 x 10 x 4 mm

Water absorption at 23°C after 24 h

% by wt.

ISO 62

80 x 80 x 1 mm

Mechanical properties, measured under standard conditions, ISO 291-23/50 Tensile strength at 23°C

MPa

ISO 527 part 1/2; test speed 5 mm/min

Multi-purpose test specimen to ISO 3167

Tensile strength at 80°C

MPa



Elongation at break at 23°C

%




%



Tensile modulus at 23°C

MPa




MPa



Flexural strength at 23°C

MPa

ISO 178

80 x 10 x 4 mm from multi-purpose test specimen to ISO 3167


MPa

ISO 178


Flexural strain at flexural strength at 23°C

%

ISO 178



%

ISO 178


Flexural modulus at 23°C

MPa

ISO 178



MPa

ISO 178


Impact strength (Charpy) at 23°C

kJ/m2

ISO 179 1eU


Impact strength (Charpy) at -30°C

kJ/m2

ISO 179 1eU


Notched impact strength (Charpy) at 23°C

kJ/m2

ISO 179 1eA


Notched impact strength (Charpy) at -30°C

kJ/m2

ISO 179 1eA


Notched impact strength (Izod) at 23°C

J/m

ASTM D 256


Notched impact strength (Izod) at -30°C

J/m

ASTM D 256


Puncture energy at 23°C

J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Puncture energy at -30°C

J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Maximum force

N

ISO 6603 part 2

60 x 60 x 2 mm

Heat deflection temperature HDT/A (1.8 MPa)

°C

ISO 75 part 1/2


Heat deflection temperature HDT/C (8.0 MPa)

°C

ISO 75 part 1/2


Thermal properties

10

Celstran®

Compel®


Celstran PP PP-GF30-04

PP-GF30-05

PP-GF40-04

Celstran PE-HD PP-GF40-05

PP-GF50-04

PE-HD-GF60-01

30

30

40

40

50

60

1.12

1.12

1.22

1.22

1.33

1.51

–

–

–

–

–

–

95

75

110

100

125

90

52

–

63

–

70

–

2.3

2.8

2

2.3

1.8

1.6

2.9

–

2.5

–

2.4

–

7,200

5,300

9,100

7,300

11,700

12,000

4,400

–

6,500

–

7,200

–

160

135

190

155

200

88

95

–

100

–

105

–

2.9

3.7

2.7

3.2

2.4

–

3.7

–

3.6

–

3.2

–

7,000

5,300

9,500

7,100

11,100

9,000

4,800

–

6,400

–

7,200

–

48

60

59

70

59

–

44

–

55

–

57

–

18

23

16

25

19

–

20

–

13

–

14

–

–

–

–

–

–

–

–

–

–

–

3.9

–

4.8

–

6.3

–

4.9

–

–

3

296

5.1

–

6.1

–

–

–

–

–

148

–

152

–

155

121

122

–

128

–

132

–

11

Celstran®

Compel®


Physical property

Unit

Test method

Test specimen


% by wt.

ISO 3451, part 1


Density

g/cm3

ISO 1183

10 x 10 x 4 mm


% by wt.

ISO 62

80 x 80 x 1 mm


MPa




MPa




%




%




MPa




MPa




MPa

ISO 178



MPa

ISO 178



%

ISO 178



%

ISO 178



MPa

ISO 178



MPa

ISO 178



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eA



kJ/m2

ISO 179 1eA



J/m

ASTM D 256



J/m

ASTM D 256



J/mm

ISO 6603 part 2

60 x 60 x 2 mm


J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Maximum force

N

ISO 6603 part 2

60 x 60 x 2 mm


°C

ISO 75 part 1/2



°C

ISO 75 part 1/2


Thermal properties

12

Celstran®

Compel®


Celstran PA66 PA66-GF40-02 DAM

PA66-GF40-02 cond.

PA66-GF40-01 DAM

PA66-GF40-01 cond.

PA66-GF50-02 DAM

PA66-GF50-02 cond.

40

40

40

40

50

50

1.45

1.45

1.44

1.44

1.56

1.56

0.55

0.55

0.55

0.55

0.4

0.4

235

170

230

155

260

190

140

120

135

115

160

130

2.4

2.8

2.2

2.3

2.4

2.5

3 3

2.9

2.5

2.6

2.4

2.7

14,000

10,200

13,000

8,700

16,200

12,300

8,100

7,500

7,800

7,100

10,500

9,600

370

290

300

245

405

320

250

210

215

195

–

–

3.5

4.1

3.2

3.8

3.2

3.8

4.1

3.7

3.4

3.9

–

_

12,300

9,800

11,100

8,600

14,800

11,700

7,500

6,800

7,200

6,500

9,500

9,000

85

95

81

91

90

95

75

–

72

65

85

80

30

30

36

36

33

34

30

30

36

37

33

34

230

240

260

300

250

295

220

–

240

280

275

–

8.6

–

–

–

8.6

–

–

–

–

–

–

–

4,950

–

–

–

4,600

–

255

255

242

242

256

256

240

240

218

218

249

249

13

Celstran®

Compel®


Physical property

Unit

Test method

Test specimen


% by wt.

ISO 3451, part 1


Density

g/cm3

ISO 1183

10 x 10 x 4 mm


% by wt.

ISO 62

80 x 80 x 1 mm


MPa




MPa




%




%




MPa




MPa




MPa

ISO 178



MPa

ISO 178



%

ISO 178



%

ISO 178



MPa

ISO 178



MPa

ISO 178



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eA



kJ/m2

ISO 179 1eA



J/m

ASTM D 256



J/m

ASTM D 256



J/mm

ISO 6603 part 2

60 x 60 x 2 mm


J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Maximum force

N

ISO 6603 part 2

60 x 60 x 2 mm


°C

ISO 75 part 1/2



°C

ISO 75 part 1/2


Thermal properties

14

Celstran®

Compel®


Celstran PA66 PA66-GF50-01 DAM

PA66-GF50-01 cond.

PA66-GF60-02 DAM

PA66-GF60-02 cond.

PA66-AF35-02

PA66-CF40-01

50

50

60

60

35

40

1.55

1.55

1.69

1.69

1.22

1.33

0.4

0.4

0.25

0.25

–

–

255

175

285

200

115

270

150

120

175

140

–

–

2.1

2.4

2.2

2.3

2

1

2.4

2.4

1.9

2

–

–

16,500

11,200

19,000

15,200

8,600

30,800

9,800

8,500

15,000

11,900

–

–

350

260

410

330

183

440

250

210

–

–

–

–

3.1

3.6

3

3.3

–

–

4.5

3.5

–

–

–

–

14,500

8,700

18,000

15,000

7,800

26,000

8,600

7,200

–

–

–

–

96

107

100

100

–

–

82

76

–

–

–

–

41

40

45

–

12

21

41

41

–

–

–

–

330

360

280

320

140

255

290

330

280

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

242

242

257

257

246

260

217

217

250

250

–

–

3

15

Celstran®

Compel®


Physical property

Unit

Test method

Test specimen


% by wt.

ISO 3451, part 1


Density

g/cm3

ISO 1183

10 x 10 x 4 mm


% by wt.

ISO 62

80 x 80 x 1 mm


MPa




MPa




%




%




MPa




MPa




MPa

ISO 178



MPa

ISO 178



%

ISO 178



%

ISO 178



MPa

ISO 178



MPa

ISO 178



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eA



kJ/m2

ISO 179 1eA



J/m

ASTM D 256



J/m

ASTM D 256



J/mm

ISO 6603 part 2

60 x 60 x 2 mm


J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Maximum force

N

ISO 6603 part 2

60 x 60 x 2 mm


°C

ISO 75 part 1/2



°C

ISO 75 part 1/2


Thermal properties

16

Celstran®

Compel®


Celstran PC/ABS

Celstran PBT/PET

PC/ABS-GF 25-02

PC/ABS-GF 40-02

PBT-GF 40-01

PBT-GF 50-01

PET-GF 40-02

PET-GF 50-01

25

40

40

50

40

50

1.36

1.5

1.65

1.75

1.7

1.8

–

–

–

–

–

–

120

152

132

166

189

165

–

–

–

–

–

–

1.8

1.4

1.25

1.3

1.8

1.1

–

–

–

–

–

–

8,100

12,000

13,500

15,000

15,300

16,000

–

–

–

–

–

–

185

235

216

262

310

252

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

7,400

11,000

11,800

13,000

13,700

14,500

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

28

–

36

–

18

–

–

–

–

–

213

182

352

454

267

347

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

107

113

213

216

249

249

–

–

–

–

–

–

3

17

Celstran®

Compel®


Physical property

Unit

Test method

Test specimen


% by wt.

ISO 3451, part 1


Density

g/cm3

ISO 1183

10 x 10 x 4 mm


% by wt.

ISO 62

80 x 80 x 1 mm


MPa




MPa




%




%




MPa




MPa




MPa

ISO 178



MPa

ISO 178



%

ISO 178



%

ISO 178



MPa

ISO 178



MPa

ISO 178



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eU



kJ/m2

ISO 179 1eA



kJ/m2

ISO 179 1eA



J/m

ASTM D 256



J/m

ASTM D 256



J/mm

ISO 6603 part 2

60 x 60 x 2 mm


J/mm

ISO 6603 part 2

60 x 60 x 2 mm

Maximum force

N

ISO 6603 part 2

60 x 60 x 2 mm


°C

ISO 75 part 1/2



°C

ISO 75 part 1/2


Thermal properties

18

Celstran®

Compel®


Celstran PPS PPS-GF 50-01

PPS-AF 35-01

Celstran TPU PPS-CF 40-01

TPU-GF 30-01

TPU-GF 40-01

TPU-GF 50-01

Celstran POM TPU-GF 60-01

POM-GF 40-01

POM-AF 30-01

50

35

40

30

40

50

60

40

30

1.72

1.35

1.46

1.43

1.52

1.63

1.76

1.72

1.42

–

–

–

–

–

–

–

–

–

148

74

158

180

209

248

230

102

106

–

–

–

–

–

–

–

–

–

1

1.3

0.5

2.8

2.55

2.4

1.6

1.1

2.3

–

–

–

–

–

–

–

–

–

18,000

8,300

35,000

8,400

11,300

15,000

18,600

12,000

8,000

–

–

–

–

–

–

–

–

–

265

138

297

272

300

363

408

182

137

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

17,000

8,380

30,000

8,000

10,000

13,000

16,000

11,000

6,000

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

23

9

–

41

48

–

58

28

–

–

–

–

–

–

–

–

–

–

359

125

161

426

588

645

692

374

421

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

282

260

277

85

91

96

102

160

157

–

–

–

–

–

–

–

–

–

3

19

Celstran®

Compel®


4. Physical Properties

Fig. 4.1 · Long-fibre reinforcement in a threaded part reduces notch sensitivity in the thread root

4.1 General information Sections 4. “Physical Properties” and 5. “Environmental Effects” deal with the important properties that are descriptive of Celstran and Compel, specifically – where available – as a function of temperature and time. All properties are determined by standardized test methods wherever possible. A survey of the physical properties is given in section 3. “Material Data”. The values are also available as a data sheet.

20,000 Long-fibre materials 10,000

Short-fibre materials Unreinforced termoplastics

0

100

300

400

500

J/m

700

Izod notched impact strength K (ASTM D 256)

17

17.2

10 5 0

= 307 N/mm2 = 1.33 g/cm3

15

Celstran PA66-GF60

Celstran PA66-GF50

9.8

5.1

5.9

Steel*

Zinc*

Celstran PA66-CF40

Aluminium*

= 225 N/mm2 = 1.80 g/cm3

16.5

= 285 N/mm2 = 1.69 g/cm3

20

= 370 N/mm2 = 7.40 g/cm3

23.5

= 345 N/mm2 = 6.00 g/cm3

30 km 25

= 270 N/mm2 = 2.80 g/cm3

Fig. 4.3 · Specific strength of Celstran PA – reinforced with glass fibres or carbon fibres – compared with metals

Celstran PA66-GF40

20

200

= 260 N/mm2 = 1.56 g/cm3

Generally speaking, long-fibre-reinforced plastics have a high modulus of elasticity – typical values are between 10,000 and 20,000 MPa – with no change in their good impact and notched impact strength, fig. 4.2. Owing to their high rigidity and strength longfibre-reinforced plastics are able to replace metals. In specific strength they far surpass metals, fig. 4.3.

MPa

= 235 N/mm2 = 1.45 g/cm3

Of particular importance to designers is the very sharply reduced creep tendency brought about by the long-fibre reinforcement. The orientation of the reinforcing fibres frequently contributes to a reduction in notch sensitivity. A typical example is a screw injection-moulded from Celstran: the fibre orientation gives it increased strength in the thread root between the thread flights, fig. 4.1.

30,000

Flexural modulus E

- impact strength, notched impact strength, low-temperature impact strength, - energy absorption capacity under impact stress, - rigidity and strength at elevated temperatures, - mechanical and thermal properties in continuous service (creep, fatigue), - reduced warpage.

Fig. 4.2 · Comparison of the typical performance ranges of unreinforced, short-fibre-reinforced and long-fibre-reinforced thermoplastics

Specific strength sp

With gentle processing a skeleton-like fibre structure is formed in Celstran and Compel mouldings. As a result they have properties characteristic of fibre composites. Compared with short-fibre-reinforced plastics there is a substantial improvement particularly in

12.7

Magnesium*

*typical values

Celstran®

Compel®


Fig. 4.4 · Density of some long- and shortfibre-reinforced plastics compared with light metals

4.2 Mechanical properties 4.2.1 Preliminary remarks

2.8

The properties of Celstran are determined by the standard test methods used for the ®Campus materials data base. These properties make it easier for designers to make a preliminary selection of materials.

g/cm3

1.36

1.45

1.22

1.12

Aluminium

1.36

Magnesium

1.2

1.33

PA66-GV30 short fibres

1.4


1.6

Celstran PP-GF50

1.8

Celstran PP-GF40

2.0

Celstran PP-GF30

Density

2.2


2.4

1.0

Fig. 4.5 · Comparison of the volume price of Celstran PP and short-fibre-reinforced PA66 that result from differences in density, assuming identical prices per kilo

DM/l 7.25

Volume price

7.00

6.80

Celstran PP-GF50 Density: 1.33 g/cm3

PA6-GV30 short fibres Density: 1.36 g/cm3

6.00

PA66-GV40 short fibres Density: 1.45 g/cm3

6.65

Celstran PP-GF40 Density: 1.22 g/cm3

8.00

6.10

5.00 5.00 DM / kg (price per kilo assumed as an example)

A special advantage of Celstran PP is its low density compared e.g. to short-glass-fibre-reinforced PA, fig. 4.4.

The physical property values given in section 3. “Material Data” may vary from those reached in mouldings owing to different production conditions and processing parameters. In the case of Compel the values – also given in section 3. “Material Data” – were determined on specimens taken from compression-moulded parts. These values are therefore not comparable with those for Celstran. They reflect with reasonable accuracy the property values actually attained in mouldings. In dimensioning components the long-term properties and possibly the temperature-dependency of the properties as well as the values obtained under short-term stress must be taken into account. It is these long-term properties that are improved by long-fibre reinforcement compared with the unreinforced or short-fibre-reinforced matrix materials. 4.2.2 Short-term stress Reinforcement with long fibres improves in particular strength and modulus of elasticity at elevated temperatures and/or under long-term stress compared with short-fibre reinforcement. Long-fibre reinforcement also gives better impact strength. This is shown in fig. 4.6 for some important application properties of Celstran PP with chemically coupled glass fibres. The flexural strength and flexural modulus values of a Celstran PP-GF40 are almost doubled compared with a PP with 30% by weight short glass fibres. The value for Charpy notched impact strength is nearly three times higher. A corresponding picture emerges for PA, i.e. with PA66 as matrix material, fig. 4.7.

Because of their low volume price resulting from their low density, Celstran PP components can offer substantial cost advantages over short-glass-fibrereinforced PA66 and PA6, even if the fibre content in the PP is higher than that in the PA, fig. 4.5.

21

4

Celstran®

Compel®


Fig. 4.6 · Improvement in some typical mechanical properties of glass-fibre-reinforced PP on switching from commercial short-fibre products to commercial long-fibre products

20,000 60%

Tensile strength [MPa] 9,100

115

6,200

Flexural strength [MPa]

80

PP short-fibre compound

100

MPa

5,500

PPlong-fibre pellets,

9

Charpy notched impact strength [kJ/m2]

cemically coupled

20

Flexural modulus E

Tensile modulus [MPa]

195

Fig. 4.8 · Tensile strength and flexural modulus of some Celstran PA66 grades compared with short-glass-fibre-reinforced PA66

Flexural modulus [MPa]

Tensile modulus [MPa]

PA short-fibre compound

305

10,700

PAlong-fibre pellets,

13

freshly moulded

200 MPa 150

300

Celstran PA66-GF50

conditioned

Celstran PA66-GF40

100


50

Charpy notched impact strength [kJ/m2]

0 0.5

0

1

1.5

32

2.5

2 Strain

3

%

4

ε

35 50

Fig. 4.10 · Stress-strain curve for Celstran POM-GF40

15,000

Flexural modulus [MPa]

MPa

250

Fig. 4.9 · Stress-strain curves for Celstran PA grades and short-glass-fibre-reinforced PA66

Stress

260 210

200

Tensile strength [MPa]

17,000

PA66 short fibres

Tensile strength

Fig. 4.7 · Improvement in some typical mechanical properties of glass-fibre-reinforced PA66 on switching from commercial short-fibre products to commercial long-fibre products

405

40% 10,000

25% 5,000 150

Fibre content [%]

50%

40%

30% 40

13,000

15,000

30

9,500

Flexural strength [MPa]

Celstran PA66

Fibre content [%] 120

Reinforcement with long glass fibres also increases the tensile modulus and tensile strength when POM is used as the matrix material, as shown by the stressstrain diagram for Celstran POM-GF40, fig. 4.10.

22

MPa

80 Stress

The combination of high flexural modulus and high tensile strength, fig. 4.8, opens up particularly in the case of Celstran PA fields of application in which light metal castings have been used in the past. In this substitution the benefits of the high rigidity of the Celstran PA grades, especially compared with shortfibre-reinforced PA, are a clear advantage, fig. 4.9.

40

0 0

0.4

0.8 Strain

ε

%

1.2

Celstran®

Compel®


4.2.3 Creep properties Designers have to know the creep properties of components subject to constant mechanical stress. Depending on the test conditions, these properties indicate how

In similar fashion to when PP is used as matrix material, the long glass fibres in PA66 reduce the creep tendency substantially. This is evident particularly at high load with a tensile stress of 90 MPa, fig. 4.12. Details of the creep properties of Celstran PA66-GF40 – measured in accordance with ISO 899 part 1 – are given in figs. 4.13 and figs. 4.14. The corresponding details for Celstran PA66-GF60 are given in figs. 4.15 and figs. 4.16.

- strain at constant stress increases with time (creep test to ISO 899 part 1) - stress at constant strain decreases with time (stress relaxation test to DIN 53441). Fig. 4.11 · Creep curves for two Celstran PP grades (PP-GF40 and PP-GF50) compared with short-glassfibre-reinforced PP (PP-GF30) and short-glass-fibrereinforced PA66 (tensile stress: 35 MPa) 4 %

For stress at high temperature and very high load (120°C and 120 MPa) fig. 4.17 shows the creep properties of Celstran PP-GF40 characterized by the flexural creep modulus compared with a shortfibre-reinforced PP. In this accelerated test the longfibre-reinforced material does not fail even after a time under load of 100 hours.

Strain

3

2

1

Fig. 4.13a · Characteristic values for the creep behaviour of Celstran PA66-GF40: creep curves for various stress values

PP-GV30 short fibres

3


Celstran PP-GF40

100

%

90

1 Celstran PP-GF50 1

10 Time t

100

h

1,000

70

0.1

Strain

0

50

0.3

30 0.1

Fig. 4.12 · Decrease in creep tendency of PA66 when reinforced with long fibres: comparison of a short-glass-fibre-reinforced material and Celstran PA66-GF40 (tensile stress: 90 MPa) 2.5


%

0.03 10-1

100

101 Time t

102

h

103

Fig. 4.13b · Characteristic values for the creep behaviour of Celstran PA66-GF40: creep curves for various strain values

2 Strain

Equivalent stress 10 MPa

1.5 Celstran PA66-GF40

300

1

0.1

1

10 Time t

100

h

1,000

The increase in strain under constant load, known as flow, shown in stress-strain curves is considerably less in the case of Celstran PP than in the case of a comparable short-fibre-reinforced PP, fig. 4.11. As the diagram shows, the creep tendency is even less than that of short-fibre-reinforced PA66.

Equivalent stress

0.5

0

MPa 1.0% 100

0.8%

0.6% 0.4%

30

strain 0.2% 10 10-1

100

101 Time t

102

h

103

23

4

Celstran®

Compel®


Fig. 4.14a · Characteristic values for the creep behaviour of Celstran PA66-GF40: stress-strain curves for various times under stress

MPa 10

75

104

Equivalent stress

MPa

102 103 (extrapolated)

0

0

300

0.1h 1

Time under stress T

Equivalent stress

100

Fig. 4.15b · Characteristic values for the creep behaviour of Celstran PA66-GF60: creep curves for various strain values

50

25

0.6 0.5

100 0.4

0.3 30

0.2 Strain 0.1%

10 10-1

0 0

0.4

0.8 Strain

1.2

%

1.6

Fig. 4.14b · Characteristic values for the creep behaviour of Celstran PA66-GF40: creep modulus as a function of time for various stress values

100

0 Equivalent stress

Creep modulus Ec

50 75 Equivalent stress 100 MPa

5,000

0 10-1

101 Time t

100

102

h

1

Creep modulus Ec

70

Strain

50 30

0.1 Equivalent stress MPa

24

50 104 (extrapolated) 25

0

0.25

0.50 Strain

0.75

%

1

MPa

90

100

102 103

25,000

%

0.03 10-1

10

Fig. 4.16b · Characteristic values for the creep behaviour of Celstran PA66-GF60: creep modulus as a function of time for various stress values

100

0.3

103

1

75

0

103

Fig. 4.15a · Characteristic values for the creep behaviour of Celstran PA66-GF60: creep curves for various stress values

h

Time under stress T 0.1h

MPa

25

10,000

102

Fig. 4.16a · Characteristic values for the creep behaviour of Celstran PA66-GF60: stress-strain curves for various times under stress

15,000 MPa

101 Time t

100

101 Time t

20,000

25 50 75

15,000 Equivalent stress MPa

102

h

103

10-1

100

101 Time t

102

h

103

Celstran®

Compel®


Fig. 4.17 · Flexural creep modulus of Celstran PP-GF40 as a function of time compared with a PP with 40% by weight short glass fibers [6] (flexural stress: 120 MPa, temperature: 120°C) 4,000

Creep modulus Ec

MPa

Celstran PP-GF40

3,000

Compel components have even better impact strength than comparable Celstran components. The increase with PP as matrix material is about 40% for the impact-resistant formulation (Compel PP-GF30-05 P25).

2,000 PP-GV40 short fibres 1,000 failure 0 0.1

Direct information on the behaviour under impact stress is provided by the multi-axial stress in the penetration test. The results are shown in fig. 4.20 for Celstran PP and fig. 4.21 for Celstran PA. In both cases the long-fibre reinforcement substantially increases the maximum force and the fracture energy (this corresponds to the area beneath the curve).

1

10

h

100

Time under stress t

Fig. 4.19 · Flexural modulus as a function of Charpy impact strength of Celstran PP compared with short-fibre-reinforced plastics

4

15,000

4.2.4 Toughness MPa

This applies not only at room temperature but also to low-temperature impact strength, fig. 4.18. With the combination of high flexural modulus and very good impact strength, fig. 4.19, the long-fibre-reinforced Celstran can be used in those cases in which this combination of properties is not adequate in shortfibre-reinforced plastics. Fig. 4.18 · Improvement in low-temperature impact strength by long-fibre reinforcement: comparison of various Celstran PP grades with short-glass-fibre-reinforced PP and with short-glass-fibre-reinforced PA66

Izod notched impact strength

40% 35%

25%

PA-GV 25% short fibres conditioned

20% PP-GV short fibres 10

20

30

40

Charpy impact strength

50

kJ/m2

70

s

Fig. 4.20 · Force-deflection curve in the instrumented puncture test on Celstran PP-GF40 and a polypropylene with 40% short glass fibres 4,000 N

Celstran PP-GF50

400

long fibres long fibres long fibres

Celstran PP-GF30

2,000 Celstran PP-GF40 1,000


short fibres short fibres

PP-GV30 short fibres 0 -40

35%

3,000

Celstran PP-GF40

200

30% 5,000

0

Force F

K*

J/m

PA-GV short fibres freshly moulded

10,000

0

800

600

Celstran PP-GF

50% Flexural modulus E

Toughness is crucial to the behaviour of a component under impact stress. As already shown in figs. 4.6 for Celstran PP and 4.7 for Celstran PA, long-fibre reinforcement brings an above-average increase in impact strength.

-30

-20

*according to ASTM D 256

-10

0

Temperature [°C]

°C

20

PP-GV40 short fibres 0 0

5

10 Deflection s

15

mm

20

25

Celstran®

Compel®


Fig. 4.21 · Force-deflection curve in the instrumented puncture test on Celstran PA66-GF40 and a polyamide with 40% by weight short glass fibres

Fig. 4.23 · Flexural fatigue strength of Celstran PP-GF40 compared with PP reinforced with 30% by weight short glass fibres 70

5,000 N

MPa Stress amplitude

A

4,000

Force F

3,000

2,000

50

Celstran PP-GF40

40

PP-GV30 short glass fibres

30 20

Celstran PA66-GF40

1,000

103

104

105

106

107

108

Number of cycles n

PA66-GV40 short fibres 0 0

2

4

6

mm

8

Deflection s

4.2.5 Fatigue

4.2.6 Surface properties

Components that are subject to fluctuating stress must be dimensioned by means of the fatigue strength.

Celstran mouldings generally have a good surface because of the good flowability of the melt. For parts with visible surfaces the following grades are highly suitable:

The long-fibre reinforcement substantially increases the fatigue strength at room temperature and especially at elevated temperature and high load compared with short-fibre reinforcement, fig. 4.22. The flexural fatigue strength*) of Celstran PP-GF40 compared with a short-fibre-reinforced PP is shown in fig. 4.23. Fig. 4.22 · Results of the tensile fatigue test on glass-fibre-reinforced polypropylene at elevated temperature (70°C) Stress amplitude

MPa

Number of cycles until failure of Celstran PP-GF40 long fibres


80

14

1

60

300

66

50

871

182

*) Fatigue strength: Stress amplitude determined in a fatigue test that a specimen withstands for a specific number of load cycles without fracture.

26

- Celstran PP grades with modification 04 (increased flowability) - Celstran PA grades with modification 01 (high gloss). In each case graining of visible surfaces is recommended. Sliding properties: As with unreinforced plastics, an addition of PTFE improves the sliding properties of Celstran. A Celstran PA-GF50 modified with PTFE to suppress the stick-slip effect is obtainable from Lehmann & Voss & Co., Hamburg, Germany. Wear: Like the sliding properties, wear is a characteristic of the system. Abrasion is dependent on variables such as sliding partner, surface pressure, sliding speed and lubrication. Under comparable conditions Celstran PP and Celstran PA generally display less abrasion than corresponding short-fibre-reinforced materials, fig. 4.24: abrasion against steel of longand short-fibre-reinforced PA66 (40% by weight glass fibres).

Celstran®

Compel®


Fig. 4.24 · Abrasion against steel of long- and short-fibre-reinforced PA66 (40% by weight glass fibres) 8

Fig. 4.25 · Coefficients of thermal expansion (range: –30 to +30°C) of some frequently used Celstran grades Material

Taber abrasion method

Coefficient of expansion (-30 to +30°C) in flow direction 10-6 · °C-1

perpendicular to flow direction 10-6 · °C-1

PA66 unreinforced

90

not measurable

PA66-GF40 PA66-GF50 PA66-GF60

19 17 15

not measurable not measurable not measurable

PA66-CF40

13

not measurable

PP unreinforced

83

not measurable

PP-GF30 PP-GF40 PP-GF50

16 15 13

36 34 17

PET-GF40

16

72

PBT-GF40

19

75

PC/ABS-GF40

18

70

Fibre reinforcement substantially reduces the coefficient of linear thermal expansion of plastics. Because of the skeleton structure the differences in flow direction and perpendicular to it are less than for comparable short-fibre-reinforced materials.

PPS-GF50

12

39

TPU-GF40 TPU-GF50

13 10

52 50

TPU-CF40

18

64

The coefficient of expansion of Celstran reaches values of 10 to 20 · 10–6 · °C–1 in the temperature range –30 to +30°C for the different test specimen geometries, fig. 4.25. It is thus in the same range as steel (12.1 · 10–6 · °C–1) and aluminium (22.5 · 10–6 · °C–1).

Blends PA66-SF6

66

74

ABS-SF6

64

96

PC-SF10

43

–

Test material

2

Celstran PA66-GV40 (40% by weight short fibres)

4

Celstran PA66-GF40 (40% by weight long fibres)

Relative abrasion

6

0

4.3 Thermal properties 4.3.1 Coefficient of expansion

4

4.3.2 Specific heat, enthalpy Fig. 4.26 · Specific enthalpy (based on 20°C) as a function of temperature for Celstran PP-GF40 600 J/g Specific enthalpy

For designing the processing machines and moulds and for dimensioning mouldings it is necessary to know the amount of heat that has to be supplied for melting the long-fibre-reinforced thermoplastics and then removed from the mould by cooling. Fig. 4.26 shows by way of example the specific enthalpy curve of Celstran PP with 40% by weight long glass fibres as a function of temperature. The amount of heat to be removed from the mould can be calculated from the melt temperature and the demoulding temperature for Celstran PP with the values given in fig. 4.27 in accordance with the procedure in fig. 4.28.

400 300 200 100 0 0

50

100

150 200 Temperature

250

°C

350

27

Celstran®

Compel®


Fig. 4.27 Values for specific enthalpy of polypropylene, glass and Celstran PP grades, based on 20°C Temperature

Specific enthalpy in J/g, based on 20°C, of

°C

PP

Glass

Celstran PP-GF40

Celstran PP-GF50

20

0

0

0

0

0

50

55

24

46

43

40

72

100

42

82

77

71

100

160

64

131

122

112

115

200

76

163

150

138

150

310

104

248

228

207

170

400

120

316

288

260

172

445

122

348

316

283

200

525

144

411

373

334

250

660

184

517

470

422

300

795

224

624

567

510

Fig. 4.28 · Procedure for calculating the amount of heat to be removed on solidification Celstran PP-GF40: Cooling from 250°C to 72 °C

-

Enthalpy at Enthalpy at

250°C 72°C

=

heat to be removed

470 J/g 77 J/g 393 J/g

4.3.3 Thermal conductivity Generally speaking, the reinforcing fibres have higher thermal conductivity than the matrix material. Therefore the thermal conductivity of fibre-reinforced plastics rises slightly with the fibre content. The thermal conductivity of Celstran PP-GF50 black (at 30°C) is λ = 0.28 ± 0.01 W/(m·K).

28

Celstran PP-GF30

4.4 Electrical properties Reinforcement with electrically non-conductive glass fibres or aramid fibres has no appreciable influence on the electrical properties of the individual matrix material. In particular the very good electrical insulating properties and good dielectric strength of the plastics remain virtually unchanged. Of the Celstran grades with carbon fibre reinforcement PA66-CF40 has good conductivity and even some shielding effect against electromagnetic radiation. Because of these properties this material is used e.g. for the housings of laptops. By adding a small amount of stainless steel filaments the shielding effect and surface conductivity of plastics can be increased specifically. The Celstran SF masterbatches, which are described in more detail in the offprint B182 d + e “Stainless steel fiber filled plastics – shielding components” (delivery upon request), were developed specially to meet these requirements.

Celstran®

Compel®


4.5 Optical properties Fibre-reinforced thermoplastics are not transparent and are translucent only if the wall thickness is low.

Fig. 4.29 · Frequency spectra on excitation with a rectangular impulse, measured on cable trays made from Celstran PP-GF40 0.6

4.6 Acoustic properties

- they have considerably better sound-deadening properties than components made from short-fibrereinforced PA or metal - noise emission is lower because of the higher sound-deadening effect - owing to their high rigidity the natural frequency is higher, given otherwise unchanged conditions, and so additional ribs to increase the natural frequency are not necessary - they have lower oscillation amplitudes – with the same design rigidity - large-volume hollow components also attain high acoustic damping - they permit a reduction in weight because of their acoustic passivity.

0.4 Amplitude

From the acoustic point of view components made from long-glass-fibre-reinforced Celstran PP offer the following advantages:

292 Hz

dB

306 Hz

0.3

PA6-GV30 short glass fibres

0.2

Celstran PP-GF40

0.1 0.0 0

200

400

600

Hz

1,000

Frequency

4

Fig. 4.30 · Decay curve on excitation with a rectangular impulse, measured on cable trays made from Celstran PP-GF40 and from a PA6 with 30% by weight short glass fibres 100 % Relative amplitude


The good acoustic damping is shown by oscillation measurements on cable trays for the electronic engine control system of cars: because of its lower weight and higher rigidity the cable tray made from Celstran PP-GF40 has a higher natural frequency at a much lower amplitude than a cable tray made from PA6 with 30% by weight short glass fibres, fig. 4.29.

60 40 Celstran PP-GF40 20 0 0

0.05

0.10

0.15

s

0.20

Time t

Because of their good acoustic damping properties components made from Celstran have good sounddeadening properties, fig. 4.30.

29

Celstran®

Compel®


5. Environmental Effects

Fig. 5.1 · Shear modulus of Celstran PP-GF40 as a function of temperature compared with conditioned PA6 and PA66, each with 30% by weight short glass fibres

5.1 Thermal properties 5.1.1 Heat deflection temperature

The long-fibre reinforcement of Celstran PP-GF40 accounts for the shear modulus up to a temperature of 130°C being higher than that of short-glass-fibrereinforced PA6 and PA66, fig. 5.1. Shear modulus of Celstran PA is plotted against temperature in fig. 5.2. The long-fibre reinforcement furthermore significantly reduces the creep tendency compared with that of corresponding short-fibre-reinforced plastics. This is shown by stress-strain curves of PP measured at 120°C, fig. 5.3.

MPa Shear modulus G

Because of the long-fibre reinforcement the heat deflection temperature of all Celstran grades is significantly higher than that of the corresponding shortfibre-reinforced matrix materials.

5,000

2,000

Celstran PP-GF40

1,000

500

PA66-GV30 cond. short fibres PA6-GV30 cond. short fibres

200 -50

0

50 Temperature

°C

150

Fig. 5.2 · Shear modulus of various Celstran PA grades as a function of temperature 16,000 Celstran PA66-GF60-02

5.1.2 Heat ageing

Celstran PA66-GF50-02

The heat ageing of plastics is not a pure material property but is also dependent on environmental circumstances, the loading condition and the natural colour of the material.

Shear modulus G

MPa

8,000

4,000

The base material used for Celstran PP is stabilized effectively against thermo-oxidative degradation and therefore displays good ageing properties.

0 -50

Because of their good heat ageing properties lightly stressed Celstran PP components are suitable for continuous service temperatures up to 130°C. Under short-term stress – up to about 1,000 hours – temperatures up to 150°C can be tolerated (medium: air).

Celstran PA66-GF40-02

0

50

100 150 Temperature

°C

250

Fig. 5.3 · Creep curves for Celstran PP-GF40 compared with a PP with 40% by weight short glass fibres 1

The base material of the heat-stabilized Celstran PA (modification -02) is stabilized against thermo-oxidative and hydrolytic degradation. Components made from heat-stabilized Celstran PA are suitable under low loading for continuous service temperatures up to 150°C and for short periods – up to about 1,000 hours – for temperatures of 170 to 200°C

30


% Strain

In the flexural test based on ISO 178 the flexural modulus and flexural strength even rise slightly after heat ageing, whereas the strain, normally highly sensitive to ageing, falls only slightly, fig. 5.4.

0.5 Celstran PP-GF40

0

0

500

1,000 Time t

h

1,500

Celstran®

Compel®


Fig. 5.4 · Heat ageing of Celstran PP-GF40-04-P10 black

Fig. 5.6 · Heat ageing of Celstran PA-GF50-02-P10 black 14,000

150°C

10,500 10,000

130°C

9,500 Flexural strain at break

Flexural modulus EB

MPa

MPa 12,000 10,000 2.0

2.30 %

130°C

2.10 2.00

%

Strain

Flexural modulus E

11,500

1.8

150°C

1.90

1.6 450

10

100 h Heat ageing time t

Flexural modulus EB

12,000 MPa 10,000

250

freshly 100 500 h 1,000 200 moulded Heat ageing time t

5.2 Flammability The behaviour of numerous Celstran grades in the event of fire has been tested and classified to UL 94. Fig. 5.7 shows an extract from these ratings, which are constantly being updated. Celstran PP-GF30 test specimens have withstood exposure to edge and surface flame application in accordance with DIN 4102 B2.

8,000 2.2 %

Strain

MPa 350

1,000

Fig. 5.5 · Heat ageing of Celstran PA-GF40-02-P10 black

2.0

Fig. 5.7 · UL rating of flammability and relative temperature index (RTI) of some Celstran PP and PA grades

1.8

B

MPa

strength

330 Flexural

B

130°C

160 150

Flexural

170

150°C

strength

B

Flexural

MPa

strength

190

300 270

freshly 100 500 h 1,000 200 moulded Heat ageing time t

(medium: air). At a temperature of 150°C even after more than 500 hours heat ageing Celstran PA66GF40-02 has a flexural modulus of over 10,000 MPa, fig. 5.5, while Celstran PA66-GF50-02 has a flexural modulus of over 12,000 MPa, fig. 5.6. Because of their good heat ageing properties the Celstran PA grades frequently replace light metals in the manufacture of complex castings. They usually permit considerably higher functional integration.

Material

Colour

Thickness [mm]

Flamm. class UL 94

Polypropylene PP-GF30 PP-GF40 PP-GF50

natural natural natural

1.57 1.57 1.57

HB HB HB

65 65 65

65 65 65

65 65 65

natural black natural black all

1.57 3.17 1.57 3.17 1.5 3.0 1.57 3.17 1.2

HB HB HB HB HB HB HB HB V-0

65 65 65 65 65 65 65 65

65 65 65 65 65 65 65 65

65 65 65 65 65 65 65 65

Polyamide PA66-GF40 PA66-GF50 PA66-GF50HG PA66-GF60 PA6-CF35-10

natural black black

Temperature index elec. mechan. with without impact impact

31

5

Celstran®

Compel®


In the flammability test to FMVSS 302 frequently used in the vehicle industry the following values were recorded on 1-mm thick test specimens: - Celstran PP-GF40 burning rate 1.61 inch/min, - Celstran PP-GF50 burning rate 1.63 inch/min. Both materials thus qualify for a standard burning rate of less than 4 inch/min. Their burning rate is below the value of 2.37 inch/min measured on shortfibre-reinforced PP-GV30.

5.3 Chemical resistance The chemical resistance is influenced essentially by the base material. Celstran PP and Celstran PA are resistant to glycol-water mixtures (engine cooling in cars) up to 135°C. The changes with time of the mechanical properties at 132°C are shown in fig. 5.8, fig. 5.9, fig. 5.10 and fig. 5.11. 5.4 Weathering and UV resistance Celstran PP and Celstran PA can be supplied on request with highly effective light stabilization.

Fig. 5.8 · Effect of heat ageing at 132°C in a glycol-water mixture on the flexural strength of various Celstran grades

Fig. 5.10 · Effect of heat ageing at 132°C in a glycol-water mixture on the tensile strength of various Celstran grades

400

250

Celstran PA66-GF40-02P10 black

MPa

200

Celstran PP-GF50-04P10 black

100

0


Z


Tensile strength

Flexural strength

B

MPa


150

100 Celstran PP-GF50-04P10 black

50

0

250

500 Immersion time t

750

h

0

1,000

Fig. 5.9 · Effect of heat ageing at 132°C in a glycol-water mixture on the Charpy impact strength of various Celstran grades

0

250


750

h

1,000

Fig. 5.11 · Effect of heat ageing at 132°C in a glycol-water mixture on the elongation at break of various Celstran grades

100

3 Celstran PA66-GF40-02P10 black Celstran PA66-GF40-02P10 black

% Tensile strain at break

Charpy impact strength a

kJ/m2

60 Celstran PA66-GF30-02P10 black 40

20

32

0

250


750


1.5 1

Celstran PP-GF50-04P10 black

0.5

Celstran PP-GF50-04P10 black 0

2

h

1,000

0

0

250


750

h

1,000

Celstran®

Compel®


6. Processing Celstran is intended for injection moulding, blow moulding and extrusion. Compel is suitable for plasticizing/compression moulding. In processing all Celstran and Compel grades care should be taken to ensure that fibre breakage is kept to a minimum. The longer the glass fibres in the component, the better are its mechanical properties.

6.2 Injection moulding of Celstran including mould making Celstran can be processed by the various injection moulding methods commonly used for thermoplastics. For the gentlest possible melting it is generally recommended that screw speed, injection speed and back pressure should be kept as low as possible.

6.1 Preparation 6.2.1 Machine requirements The pellets should be stored in a dry place in closed containers until they are processed so as to prevent contamination and moisture absorption (including condensation). Celstran PP and Compel PP: drying is not normally required before processing. Should the material have become damp owing to incorrect storage, it must be dried for 2 hours at 80°C. Celstran PA: drying in a dehumidifying dryer for 4 hours at 80°C is recommended in principle before processing. Other Celstran grades: drying in a dehumidifying dryer is in principle recommended before processing. The drying conditions are given in the product data sheet – see fig. 6.5.

Fig. 6.1 · Metering Screw for Celstran Materials

All Celstran grades can be processed on commercial injection moulding machines. For optimum care of the reinforcing fibres and to prevent feed problems because of the relatively long pellets, fairly large plasticizing machines should be used, preferably with a screw diameter of more than 40 mm. Pellets 7 mm long are available for processing glassfibre-reinforced Celstran PA66 grades on smaller machines. Three-zone screws are recommended, fig. 6.1, if possible with a deep-flighted feed zone, low compression ratio and a three-piece annular nonreturn valve of large cross-section to ensure smooth even flow, fig. 6.2. Plasticizing units with mixing zones are in principle not suitable.

Fig. 6.2 · Three Piece Screw Tip Ring Valve

total length generously dimensioned slots for gentle melt throughput

effective screw length outside diameter

non-return valve

shaft length

feed zone

compression zone

metering zone

highly polished

flight depth, feed zone

flight depth, metering zone

precision-ground mating surfaces for good seal

screw tip

33

5

6

Celstran®

Compel®


Since all Celstran grades contain reinforcing fibres, it is necessary for the plasticizing unit to be wear-resistant. Depending on the matrix material, additional corrosion protection may be necessary, e.g. for PA66 or PPS. Details of recommended machine equipment are given in fig. 6.3. Pneumatic conveying equipment has proved successful for automatic material supply. The diameter of the conveying lines should be at least 40 mm. Low air speeds (up to about 16 m/s) should preferably be used. Suction tubes cut at an angle have proved successful for feeding the product. Gravimetric metering equipment is recommended for producing blends with a fairly low fibre content. The conveying and metering equipment used in producing conductive blends of Celstran with stainless steel filaments must not have any magnetic components. These blends can also be processed on machines with smaller screws (diameter 20 mm and above) owing to the good stability of the stainless steel filaments. Fig. 6.3 · Recommended equipment and parameters for injection moulding machines for processing Celstran PP and Celstran PA Celstran PP Machine size Screw Non-return valve

Celstran PA

preferably fairly large machines standard 3-zone screw, screw diameter preferably ≥ 40mm streamlined non-return valve for good flow, with large cross-section

L/D

18 : 1 to 22 : 1

18 : 1 to 22 : 1

Compression ratio

1 : 1.8 to 1 : 2.5

1 : 1.8 to 1 : 2.5

Functional zone ratios

feed 50 to 60% compression 20 to 30% metering 20%

Flight depth

feed zone preferably ≥ 4.5mm

Steel quality

Shot weight

wear-resistant steels HRC ≥ 56

wear-resistant and corrosionresistant steels HRC ≥ 56

30 to 60% of machine capacity

Nozzle

open, diameter ≥ 4mm, preferably ≥ 6mm, own temperature control for the nozzle

Gating

if possible central sprue gate, diameter ≥ 4 mm, preferably ≥ 6mm, all flow channels streamlined for good flow, gate diameter ≥ 3mm, if possible no pin or film gates

Predrying

34

4h at 80°C dehumidifying dryer

6.2.2 Processing conditions Celstran can be injection-moulded without any problems. Machine settings that result in optimum finished parts are dependent on the moulded part geometry, the injection mould and the injection moulding machine used. Settings that have proved successful are given in - fig. 6.4 for Celstran PP and Celstran PA, - fig. 6.5 for other Celstran grades. Plasticizing and cylinder temperatures Gentle plasticizing is necessary to keep fibre length reduction during melting to a minimum. The required melt temperature is achieved firstly by cylinder heating (heat supply from outside by heat conduction) and secondly by friction (heat supply through internal and external friction, produced by back pressure and screw speed). The melt shear occurring on melting may shorten the long reinforcing fibres. It is therefore particularly important to maintain very low back pressure or even to plasticize without back pressure, but at the same time to ensure uniform metering and adequate melt homogeneity. It is recommended that the screw speed should be as low as possible so that about 90% of the cooling time can be utilized for metering. In order for a maximum amount of heat to be supplied via the cylinder heating, the pellets should melt rapidly in the feed zone. For this material, therefore, a somewhat higher temperature profile should be chosen than for processing corresponding short-fibre compounds. Mould wall temperatures The recommended mould wall temperatures are governed by the matrix material. Details are given in figs. 6.4 and 6.5. For Celstran PP mould wall temperatures of 40 to 50°C have proved successful. Mouldings with a very good surface are obtained if the mould wall temperature is raised to 70°C. The mould wall temperatures for Celstran PA are normally 90°C.

Celstran®

Compel®


Fig. 6.4 · Processing conditions for Celstran PP and PA Celstran PP PP-GF30

PP-GF40

PP-GF50

Celstran PA heat stabilized = 02 high-gloss = 01 PA66-GF40 PA66-GF50 PA66-GF60 PA66-GF40 PA66-GF50 PA66-GF60

Temperature cylinder

[°C]

230 to 270

250 to 290

250 to 290

275 to 310

280 to 315

285 to 320

270 to 305

270 to 305

275 to 310

Temperature nozzle and melt

[°C]

240 to 270

260 to 290

280 to 290

305 to 315

310 to 320

315 to 325

290 to 305

295 to 305

295 to 310

Temperature mould

[°C]

30 to 70

40 to 70

40 to 70

80 to 120 pref. 90

80 to 120 pref. 90

80 to 120 pref. 90

70 to 110 pref. 90

70 to 110 pref. 90

70 to 110 pref. 90

[mm/sec] 40 to 60

40 to 60

40 to 60

40 to 75

40 to 75

40 to 75

40 to 60

40 to 60

40 to 60

40 to 60

40 to 60

400 to 800

400 to 800

500 to 800

500 to 800

500 to 800

Injection speed Screw speed

[min-1]

40 to 60

Holding pressure [bar] 400 to 800

Injection pressure [bar] 600 to 1200 600 to 1200 600 to 1200 1200 to 1500 1200 to 1500 1200 to 1500 Back pressure

as low as possible

as low as possible

Fig. 6.5 · Drying and processing conditions for other Celstran grades Drying Time Temp Product

Processing temperatures [±10°C] Cylinder temperatures at at hopper centre nozzle

Processing temperatures [±10°C] Nozzle Melt Mould

[h]

[°C]

Polybutylene terephthalate PBT-GF40-01P10 4 PBT-GF50-01P10 4

120 120

255 260

260 265

265 270

260 265

265 270

90 90

Polycarbonate blend PC/ABS-GF25-02P10 PC/ABS-GF40-02P10

4 4

90 90

265 270

270 275

275 280

275 280

275 280

Polyethylene PE-HD-GF60-03P10

2

90

230

240

250

240

Polyethylene terephthalate PET-GF40-01P10 4 PET-GF50-01P10 4

150 150

265 270

270 275

275 285

Polyphenylene sulphide PPS-GF50-01P10

130

305

315

Polyoxymethylene (Polyacetal) POM-GF40-01P10 3 80

195

Thermoplastic polyurethane TPU-GF30-01P10 4 TPU-GF40-01P10 4 TPU-GF50-01P10 4 TPU-GF60-01P10 4

80 80 80 80

With aramid fibres PA66-AF35-02P10 POM-AF30-01P06 PPS-AF35-01P06

4 3 4

With carbon fibres PA66-CF40-01P10 PPS-CF40-01P10 TPU-CF40-01P10

4 4 4

4

Injection speed

Back pressure

Screw speed Comments

[bar]

[min-1]

medium medium

0 to 3 0 to 3

30 to 50 30 to 50

80 80

medium medium

0 to 3 0 to 3

30 to 50 30 to 50

250

70

medium

0 to 3

40 to 60

270 280

275 285

150 150

medium medium

0 to 3 0 to 3

30 to 50 30 to 50

Predry to 0.015% moisture content

320

310

320

150

medium

0 to 2

30 to 50


200

205

205

205

80

medium

0 to 3

30 to 50

Melt < 230°C

240 245 250 255

245 250 255 260

250 255 260 265

245 250 255 260

250 255 260 265

70 70 70 70

medium medium medium medium

0 0 0 0

30 30 30 30

80 80 130

295 200 315

310 205 320

315 210 320

310 210 320

315 210 320

90 70 150

medium medium medium

0 to 3 0 to 3 0 to 3

30 to 50 30 to 50 30 to 50

80 130 80

300 305 245

305 310 250

310 315 255

310 315 255

310 315 255

90 150 70

medium medium medium

0 to 3 0 to 3 0 to 3

30 to 50 30 to 50 30 to 50

to to to to

3 3 3 3

to to to to

50 50 50 50


Predry to 0.02% moisture content Melt < 275°C

35

6

Celstran®

Compel®


Injection and holding pressure

6.2.3 Flow properties and flow path lengths

High shear can also occur in the melt in the injection operation and shorten the fibres. Therefore low injection speeds are recommended. Injection and holding pressure should be adapted to the moulded part geometry. A holding pressure of 60 to 100% of the injection pressure is recommended. To ensure as constant a moulded part quality as possible, an adequate holding pressure time must be ensured. This is achieved when the moulded part weight remains constant despite a lengthy holding pressure time with a constant total cycle time.

In the spiral flow test under simulated service conditions the Celstran PP grades reach flow path lengths up to 550 mm for 2 mm wall thickness at an injection pressure of 1,000 bar and a melt temperature of 245°C, fig. 6.7. Raising the melt temperature by 45 K to 290°C increases the flow path length by about 15%, fig. 6.8. Thus, despite reinforcement with long glass fibres the flowability of Celstran PP is better than that of standard PP compounds with a comparable short glass fibre content, fig. 6.9.

Regrind addition When Celstran is processed, it is possible to add coarsely ground production waste to virgin material of the same grade. Additions of up to 10% have virtually no adverse effect on moulded part properties [3], fig. 6.6.

6.2.4 Shrinkage

Fig. 6.6 · Change in tensile strength and Charpy notched impact strength as a result of regrind addition

Shrinkage has a major influence on the dimensional stability and warpage of a moulding. It is governed not only by the fibre content but also to a considerable extent by the fibre orientation and the processing conditions, and so shrinkage data can be no more than guide values.

100

Relative change

%

Similarly, the Celstran PA grades too have better flowability than corresponding short-fibre compounds. Even the heat-stabilized grades reach flow path lengths up to 300 mm in the spiral flow test at an injection pressure of 1,000 bar and a melt temperature of 305°C, fig. 6.10. Raising the melt temperature by only 15 K to 320°C increases the flow path length by over 20%, fig. 6.11.

Tensile strength in accordance with ISO 527-1,2, initial value 115 MPa

60 Charpy notched impact strength in accordance with ISO 179/1eA, initial value 20 kJ/m2

40 20 0 0

5

10

15 20 25 Regrind content

30

%

40

Despite reinforcement with long glass fibres the anisotropy of shrinkage, i.e. the ratio of longitudinal to transverse shrinkage, is fairly low and generally more favourable than that of short-fibre-reinforced plastics. The average shrinkage measured on test bars is 0.25% in flow direction and 0.3% in transverse direction. Owing to the low anisotropy of shrinkage the warpage tendency of Celstran components is similarly low. Additional information on the dimensional accuracy of Celstran components can be derived from the ratio of the flexural modulus in flow direction to that in transverse direction. This anisotropy is much lower in Celstran PP components than in identical components made from a corresponding short-fibre compound, as shown by tests on an injectionmoulded air intake pipe for a car engine, fig. 6.12.

36

Celstran®

Compel®


Fig. 6.7 · Flow lengths of the commercial Celstran PP grades 800

Celstran PP-GF30-04

mm 700

Fig. 6.10 · Flow lengths of Celstran PA66-GF40 and PA66-GF50 mm 500

Celstran PP-GF40-04

500 Celstran PP-GF40-03 400

Flow length

Flow length

Celstran PP-GF50-04 600

400

Celstran PA66-GF40

300 Celstran PA66-GF50

Celstran PP-GF30-03

300 800

1,000

1,200 Injection pressure

1,400

bar

200 700

1,600

Fig. 6.8 · Influence of melt temperature Tm on the flow length of Celstran PP-GF50-04

mm

Celstran PP-GF50-04

1,300

bar

Celstran PA66-GF40

500

700

Tm = 320°C

Tm = 290°C 600

Tm = 245°C

Flow length

Flow length


Fig. 6.11 · Influence of the melt temperature Tm on the flow length of Celstran PA66-GF40-02

800 mm

900

500

400 Tm = 305°C

6

300 400

300 800

1,000


1,400

bar

Fig. 6.9 · Flow lengths of Celstran PP-GF30 compared with PP with 30% by weight short glass fibres 800


1,300

bar

2.00

PP-GV30 short fibres, easy flowing

1.75 short glass fibres

600

Anisotropy

Flow length

900

Fig. 6.12 · Component anisotropy, determined from the ratio of the flexural modulus measured in flow direction and transversely to it

Celstran PP-GF30-04

mm 700

200 700

1,600

500

1.50 long glass fibres 1.25

PP-GV30 short fibres 400

1.00 Celstran PP-GV30-03

300 800

0.75 1,000


1,400

bar

1,600

10

15

20

30 40 Fibre content

%

30

37

Celstran®

Compel®


6.2.5 Gate and mould design

Fig. 6.13 · Indication of fibre length distribution of Celstran components: correctly produced moulding, critical fibre length range drawn diagrammatically [7]

For Celstran PP and Celstran PA a central sprue gate having a diameter of at least 4 mm, better 6 mm, with all runners designed to promote smooth even flow has proved successful. The diameter of the gate should if possible be greater than 3 mm. Smaller cross-sections (down to 1 mm diameter) can be chosen for blends with Celstran SF (stainless steel fibres). Pinpoint and film gates can be used with good results provided they have adequately large cross-sections. Hot runner technology for sprueless processing of Celstran can readily be used provided open hot runner nozzles are used. If the recommendations for plasticizing and mould design are observed, a moulding is obtained with a fibre length distribution in which a high proportion of fibres are above the critical length [7] (see section 1.3), i.e. with optimum reinforcing effect, fig. 6.13.

Critical fibre length range

Weight content

As with the injection unit, care must be taken to ensure minimal shortening of the reinforcing fibres in designing moulds. For this reason the diameters and radii of curvature of runners in flow direction and the cross-sections of gates must be dimensioned as large as possible.

0.8

0

Moulding

3 mm

1

5 Fibre length

mm

10

6.2.6 Special methods The usual special methods can be used for injection moulding Celstran. For example, the gas injection method has proved successful for a gear lever, fig. 6.14. Decorative effects can be achieved with two-colour injection moulding. When multicomponent injection moulding is used, for example for producing combinations of hard and soft materials, the compatibility and bond strength between matrix material and soft component must be borne in mind. Practical experience has shown that Celstran PP can also be processed without any problems by foam injection moulding, fig. 6.15. Virgin and recycled polyolefines are often processed into complex large components by special methods such as transfer moulding, low-pressure injection moulding or intrusion. In such applications the effect of Celstran or Compel is to improve properties; an addition of as little as 10 to 40% by weight gives these components the required rigidity and strength. In addition, the stable parts are easier to demould, and so shorter cycle times are possible.

38

Celstran®

Compel®


Fig. 6.14 · Gear lever made from Celstran PP-GF40 by gas injection moulding (manufacturer: Möller Plast GmbH, Bielefeld, Germany)

6.3 Blow moulding of Celstran Fundamental tests carried out by a machine manufacturer have shown that long-glass-fibre-reinforced plastics can be blow-moulded if a conventional blow moulding machine is equipped with a special screw with a gentle action for melting the pellets [8]. The long-glass-fibre-reinforced materials used for blow moulding normally have fibre contents between 5 and 30% [8]. To achieve these low contents a corresponding amount of Celstran with a higher fibre content is added to the unreinforced matrix material by means of a metering unit. 6.3.1 Materials The most important matrix material in blow moulding is PE-HD. For low fibre contents the blow moulding grade normally employed for the unreinforced blow-moulded part is used. Celstran PE-HD-GF60-01P10 is added to this material.

Fig. 6.15 · Pallet for the “Stecon”, returnable collapsible container made by foam injection moulding of Celstran PP-GF40, side walls and cover compression moulded with Compel PP-GF30

For higher fibre contents a PE-HD with a lower viscosity, i.e. with higher MFI, must be employed for uniform, gentle incorporation of the long-fibre material. In this case it is particularly important to ensure homogeneous distribution in the melt of the fibres contained in the added Celstran. This can be achieved by adapting the extruder temperatures. The long glass fibres give the melt the elasticity necessary for blow moulding. With PP as matrix material blow-moulded parts are obtained that withstand higher service temperatures. As with PE-HD, Celstran PP-GF50 is added to a PP with low melt viscosity via a metering and mixing unit so as to achieve the desired content of long glass fibres in the moulding. Blow-moulded PP parts with long glass fibres are suitable for applications in the engine compartment of vehicles. Since they do not exhibit environmental stress cracking, they can also be used for mouldings in contact with fuel, lubricants or cooling water. Because of their good strength even at elevated temperatures they are suitable for service temperatures up to 130°C under low load. In the case of both PE-HD and PP the achievable blow-up ratio is lower with reinforced plastics than with standard blow moulding materials [8].

39

6

Celstran®

Compel®


Coextrusion enables mouldings with an unreinforced inner and outer layer to be produced by blow moulding. As a result the surface quality can be influenced within wide limits. Materials with a high glass fibre content can also be processed by this method [8]. 6.3.2 Machine requirements Celstran can be processed on commercial blow moulding machines with single-screw extruders. In selecting machine and screw care must be taken to ensure that - the material is melted gently so as to minimize fibre damage and - the fibres remain uniformly distributed in the melt. The screw must not have any shear elements, in particular no Maddock shear elements. Barrier-type screws are also unsuitable because they cause considerable fibre breakage. Other mixing elements should also be avoided if possible. If it is necessary to use them, they should have an adequately large free cross-section for the melt flow. The screw diameter must be matched to the required throughput; it should be at least 40 mm. In principle large screw diameters, low compression and low speeds should be employed so as to minimize shear energy. The feed zone of the screw should be deepflighted. The compression ratio must not exceed 2:1. The energy required for melting the pellets should if possible be provided solely via the barrel heating. Shear must be avoided. The extruder must not have any screens or strainer plates because these can be blocked by the fibres.

40

6.3.3 Parison die Celstran can be processed with continuous parison dies and with accumulator heads. The glass fibres give the parison increased rigidity in longitudinal and transverse direction. As a result the parison stretches less severely than in the case of unreinforced PE-HD or PP. The long glass fibres give the melt high rigidity. The diameter of the extruded parison should be as large as possible so as to minimize the blow-up ratio. The long glass fibres reduce parison swell markedly. Fibre orientation in the component is influenced by the design of the flow channels in the parison die. The fibres are aligned in flow direction by means of spider legs. This results in weld lines, which should be located in component areas subject to low stress. Narrow flow channels also cause strong fibre orientation in longitudinal direction. Layers with differently oriented fibres often form in the parison. In melt layers flowing near the wall the fibres are oriented in longitudinal direction, whereas in the middle layer they are oriented in circumferential direction. 6.3.4 Temperatures The processing temperatures are governed by the plasticizing and homogenizing characteristics of the machine. Normally the material can readily be processed with a temperature profile similar to that for unreinforced PE-HD. Should poorly dispersed fibre bundles still be visible in the melt, the temperatures must be raised. In so doing, temperatures up to 50 K above those for unreinforced PE-HD are possible for the rear extruder zones. In the case of PP to which Celstran PP has been added it is advisable to use the temperature profile commonly employed for unreinforced PP. The temperatures should be 240°C at the heating zone, 230 and 220°C at the following zones and 210°C at the extruder tip.

Celstran®

Compel®


6.4 Extrusion of Celstran Extruded sheets and profiles can be obtained from Ensinger GmbH, Nufringen, Germany. Coextruded profiles with a Celstran core and unreinforced inner and outer layers are supplied under the trade name VHME (very high modulus extrudate) by Intek Weatherseal Product Inc., Hastings, Minnesota, USA.

Fig. 6.16 · Drawing of a plasticizing/compression moulding machine, consisting of screw plasticizing unit, vertical press and positive mould, for processing Compel [10]

6.5 Processing of Compel 6.5.1 Plasticizing/compression moulding Because of its typical fibre length of 25 mm Compel is processed mainly by a gentle combination of plasticizing and compression moulding [9]. A suitable machine is shown in fig. 6.16 [10]. Procedure Plasticizing/compression moulding comprises the following steps [10]: 1. The pellets are conveyed to the hopper and fed to the plasticizing unit. 2. A deep-flighted screw plasticizes the material gently. The screw then retracts and places the prepared melt in the enclosed space in front of it. 3. The plasticizing unit enters the opened mould. 4. The closure device at the plasticizing unit opens, the screw pushes the melt out and places it in the form of a strand in the mould. 5. The closure device at the plasticizing unit cuts off the melt strand and the unit retracts from the mould. 6. The press closes and the melt is distributed under fairly low pressure (typically 30 to 50 bar) and under low shear stress in the cavity between the top and bottom of the mould.

Fig. 6.17 · Processing conditions for the plasticizing/compression moulding of Compel PP Melt temperature 200 to 280°C, depending on the moulding Mould temperature up to 80°C

6

Closing speed as high as possible to prevent premature cooling Compression speed ≥ 5 mm/s, depending on the moulding Specific cavity pressure depending on the moulding Cooling time normally 15 s for 2 mm wall thickness, depending on the moulding

7. At the end of the cooling time the press opens. Parallel to this the plasticizing unit has prepared fresh melt. 8. The finished moulding is demoulded automatically or manually. With the placement of melt in the mould the production cycle for the next moulding begins.

41

Celstran®

Compel®


Machine and mould technology The gentle plasticizing of Compel requires special plasticizing units with a screw diameter of at least 80 mm. Reductions in cross-section caused e.g. by inserts, nozzles or deflectors should be avoided. The processing conditions for Compel PP are summarized in fig. 6.17. The rod-shaped pellets should be melted without compression. The back pressure should be as low as possible. Cylinder temperatures of 220 to 280°C can be used, depending on the moulded part geometry. The mould temperatures should be between 50 and 80°C. The mould for shaping the parts must be designed as a positive mould, as in conventional compression moulding. The same design guidelines apply to ribs, drafts etc. as for Celstran. Components of complex geometry, for example mountings and fascia panel supports for cars, can be made from Compel without any problems. A vertical hydraulic press, if possible with synchronization control, is required to hold the mould and produce the locking force. Because of the relatively low cavity pressure locking forces of 8,000 to 30,000 kN are sufficient even for large mouldings.

This and other facts of importance for recycling longfibre-reinforced plastics are investigated in the project “Material recycling of long- and continuous-fibrereinforced thermoplastics into high-quality, longfibre-reinforced flow-moulded components” by the “Deutsche Bundesstiftung Umwelt”, Osnabrück, Germany. This project is a cooperative venture involving, among others, the “Institut für Aufbereitung (IFA)”, Aachen, the “Institut für Verbundwerkstoffe GmbH (IVW)”, Kaiserslautern, and the “Institut für Kraftfahrwesen Aachen (ika)”. Further information on the processing of Compel is obtainable from Ticona. 6.5.2 Other methods Apart from plasticizing/compression moulding, injection stamping is also suitable for processing Compel. Here too, gentle melting of the pellets by an adequately dimensioned screw (diameter at least 80 mm) without a non-return valve and with low back pressure must be ensured. When the melt is injected into the still partly opened positive mould, a low injection speed is essential for protecting the fibres from damage. 6.6 Safety notes

Recycling After compression moulding of Compel, waste from punching operations is produced when openings are cut out in mouldings. This waste can amount to as much as 30% of the component weight. It can be recycled immediately in plasticizing/compression moulding provided it is granulated correctly: the fines content in the granulated material must be low. Our own investigations show that up to 30% waste from punching operations can be added to a component, depending on the stress to which it will subsequently be subjected.

Long-fibre-reinforced plastics, like many organic substances, are flammable (exceptions: Celstran PPS is not flammable, the Celstran PA6-CF30 and Celstran PC/ABS-GF40 grades are flame-retardant and reach UL 94 rating V-0). It is in the interest of the processor when storing, processing or fabricating the material to take the necessary fire prevention measures. Certain end products and fields of application may be subject to special fire prevention requirements. The statutory safety regulations vary from one country to another. In each case the local regulations are mandatory. It is the responsibility of the processor to ascertain and observe such requirements. Important information is given in safety data sheets, which are available from Ticona on request. Due to danger of thermooxidative degradation not processed plastificates must always be cooled down completely in a water basin.

42

Celstran®

Compel®


7. Finishing

Fig. 7.1 · Major variables on heated tool welding Process variables

7.1 Machining

Compression-moulded parts may require deflashing because material is unavoidably squeezed out of the mould. In many cases the flash is removed with cutting tools. Generally speaking, the high reinforcing fibre content must be taken into account in milling, drilling or turning Celstran, Compel or Fiberod parts. In principle, tools with hard metal or diamond cutters are recommended in order to achieve high-quality surfaces and long service life. 7.2 Assembly 7.2.1 Welding Of the assembly techniques for plastic mouldings the various welding methods have achieved outstanding importance. Mouldings made from long-fibre-reinforced plastics can be welded to each other or to parts made from unreinforced or short-fibre-reinforced plastics. The type and quantity of reinforcing fibres must however be taken into account in designing the weld area and in selecting the welding parameters.

Material

· Density (type of filler and content)

· Surface temperature of the heated tool

· Shear modulus (if possible high and constant over temperature profile)

· Heating pressure

· Viscosity (too low can lead to the matrix being squeezed out of the welding zone)

Moulding

Welding parameter

Injection geometry

· Moulding rigidity

· Surface defects (voids)

· Radius design (to avoid stress cracking > 5 mm)

· Dimensional variations (shrinkage, warpage)

· Weld geometry

· Processing defects (demixing, decomposition)

· Heating time · Welding pressure · Welding time · Internal stresses · Moulding contamination (e.g. release agents)

Fig. 7.2 · Heated tool butt welding of Celstran PP

6

Weld strength: 25 to 40 MPa (depending on the glass fibre content, welding parameters, moulding geometry, injection moulding) F

F

7

4

The two most important methods of processing plastics, namely injection moulding and blow moulding, produce moulded parts that normally do not require any finishing if the moulds are correctly designed.

Recommended welding parameters

In the case of glass-fibre-reinforced Celstran PP, regardless of the fibre content, heated tool welding yields the highest values for weld strength. The major variables are given in fig. 7.1. The weld strength achieved with Celstran PP is - values between 25 and 40 MPa in heated tool butt welding with the parameters given in fig. 7.2 - a tensile shear strength of about 15 MPa in heated tool lap welding under the conditions given in fig. 7.3. These values show that the weld strength is determined basically by the matrix material.

for PTFE-coated heated tool

or

for uncoated heated tool

Temperature of the heated tool: 260°C

Temperature of the heated tool: 360°C

Heating time: 10 to 20 s

Heating time: 5 to 10 s

Heating pressure: 0.5 to 0.6 MPa

Heating pressure: 0.4 to 0.5 MPa

Welding pressure: 0.5 to 0.6 MPa

Welding pressure: 0.4 to 0.5 MPa

43

Celstran®

Compel®


Fig. 7.3 · Heated tool lap welding of Celstran PP Tensile shear strength: 15 MPa (depending on the glass fibre content, welding parameters, moulding geometry, injection moulding)

F 4

4

F 15

Recommended welding parameters

Vibration welding also gives good values for weld strength. Values up to 25 MPa are achieved with Celstran PP under the conditions given in fig. 7.4. The weld strength is largely independent of the welding depth, fig. 7.5. In line with the higher strength of the matrix material the weld strength of Celstran PA rises to 45 to 55 MPa, fig. 7.6. Ultrasonic spot welding can be used instead of riveting. The characteristic welding parameters and the achievable tensile shear forces are shown in fig. 7.7.

for PTFE-coated heated tool

Fig. 7.5 · Weld strength as a function of welding depth of Celstran PP

Temperature of the heated tool: 360°C Heating time: about 20 s

30

Welding pressure: about 0.3 MPa

MPa

Fig. 7.4 · Vibration welding of Celstran PP

Weld strength

Celstran PP-GF40-04 20

Celstran PP-GF50-04

10

Weld strength achieved with Celstran PP-GF40-04: about 21 MPa Celstran PP-GF50-04: about 17 MPa

0 0

0.5

1

1.5 2 2.5 Welding depth

3

mm

4

4

Linear movement

Fig. 7.6 · Weld strength as a function of welding depth of Celstran PA

100

60 Recommended welding parameters

Weld strength

for Celstran PP, modification 04

MPa 40 Celstran PA66-GF50

20

Welding pressure: 1 MPa Welding time: 5 s 0 Welding depth: about 2.0 mm

44

0

0.5

1

1.5 2 Welding depth

mm

3

Celstran®

Compel®


Fig. 7.7 · Ultrasonic spot welding of Celstran PP Number of welding points

Tensile shear force in N where s = 3 mm s = 4 mm 2800

3400

2

4500

5200

3

6200

8200

1.5 s

1

In adhesive bonding of components made from Celstran or Compel the matrix material is of crucial importance. For instance, pretreatment of Celstran PP is necessary to lower the surface tension (corona discharge, flame application) so as to obtain bonded joints with adequate strength. Bonded joints are simpler to produce with Celstran PA. Two-pack adhesives based on polyurethane and one-pack adhesives based on cyanoacrylate give good results.

s

1.5 s

7.2.2 Adhesive bonding

3s

Recommended welding parameters Sonotrode diameter: 4 mm Amplitude: 0.05 mm Ultrasonic exposure time: 1.2 s Welding pressure: 0.25 MPa Holding time: 3 s

7

45

Celstran®

Compel®


8. Recycling Recycling of Celstran production waste (sprues, rejects) is described in section 6.2.2 “Processing conditions”. After use Celstran mouldings can be recycled. The most important requirement is to segregate Celstran from other polymers. Celstran PP recyclate can be blended with other PP recyclates. An addition of Celstran PP recyclate to unreinforced PP generally improves the latter’s properties because of the glass fibre reinforcement. The same applies to Celstran PA66 and PA66 recyclates. Further shortening of the fibres is likely in recycling, and so mouldings made from pure Celstran recyclates have poorer values than virgin Celstran material especially in impact strength.

46

Celstran®

Compel®


9. Photo supplement showing typical applications

Assembled Frontend for AUDI, Compel PP-GF40

8

9

Battery Tray for Opel Astra, Celstran PP-GF40

47

Celstran®

Compel®


Lever for Electrical Cabinet, Celstran PA66-GF50

Housing Part for Seat Belt Mechanism, Celstran PA66-GF40

48

Celstran®

Compel®


Mirror Bracket and Housing made from Celstran PP-GF50 and Hostalen PPU

9

DEU Housing for Board Communication in Airplanes, Celstran PPS-SF20 49

Celstran®

Compel®


Tilt Tray Mechanism, Celstran PP-GF40 (company: WPK, Radevormwald)

50

Celstran®

Compel®


10. Subject Index abrasion, relative 27 acoustic properties 29 adhesive bonding 45 anisotropy (shrinkage) 36 back pressure 35, 36 blow-up ratio 39 blow moulding 39, 40 bonding 45 burning-off (resin matrix) 6 chemical resistance 32 coefficient of thermal expansion 27 coloration 9 colour masterbatches 9 content of reinforcing material 10 – 19, 22 continuous service temperatures 30, 39 creep modulus 23 – 25 creep properties 23, 25 creep tendency 5, 23, 30 density 10 – 19, 21 dielectric strength 28 drilling 43 drying 33 – 35 electrical insulation 28 electrical properties 28 electromagnetic shielding 28 elongation at break 10 – 19, 31, 32 enthalpy 27, 28 environmental effects 30 – 32 extrusion (Celstran) 41 fatigue strength 26 fibre length 5, 6 fibre skeleton 6, 20 film gate 38 finishing 43 flammability 31 flexural fatigue strength 26 flexural modulus 10 – 19, 20, 22, 25, 31 flexural strength 10 – 19, 31, 32 flow path length 36 flow properties 36 fluctuating stress 26 foam injection moulding 38 form supplied 9 fracture energy in puncture test 10 – 19, 25, 26

gas injection method 38 gate design 38 GMT compression moulding 6 heat ageing 30, 31 heat deflection temperature 10 – 19, 30 heated tool welding 43, 44 hot runner technology 38 hybrid reinforcement 9 impact strength 6, 10 – 19, 25, 32 in-house coloration 9 injection moulding 33 – 38 injection moulding machines, equipment for 34 injection pressure 36 injection speed 35 intrusion 38 literature 53 long-fibre pellet 4, 6 low-pressure injection moulding 38 material data 10 – 19 matrix, thermoplastic 4 mechanical properties 10 – 19, 21 – 27 melt temperature (injection moulding) 34 – 37 metering screw 33 milling 43 mould design (injection moulding) 38 mould temperature (injection moulding) 34 – 36 nomenclature 8 non-return valve 33 notched impact strength 5, 10 – 19, 20, 25, 36 optical properties 28 outer fibre strain 8 – 17 overview of grades 5

9

parison die 40 puncture test 10 – 19, 25, 26 pinpoint gate 38 plasticizing (Celstran) 34 plasticizing/compression moulding 6, 41, 42 preparation (processing) 33 processing 33 – 42 processing conditions (Celstran) 34 – 36

10

51

Celstran®

Compel®


processing conditions (Compel) 41, 42 processing temperatures (Celstran) 35 processing temperatures (Compel) 42 properties, acoustic 28, electrical 28 mechanical 10 – 19, 21 – 27 optical 29 physical 20 – 29 thermal 27, 28 pultrusion process 4 quality management 5 recycling (Celstran) 46 recycling (Compel) 43 regrind, addition 36 safety data sheets 42 safety notes 42 screws (blow moulding) 40 screws (injection moulding) 33 screw speed (injection moulding) 34 – 36 shear modulus 30 short-fibre pellet 4 short-term stress 21, 22 shrinkage 36, 38 shut-off nozzles 38 sliding properties 26 sound deadening 29 special methods (injection moulding) 38 specific strength 20 specific heat 27 spiral test 36 sprue gate 38 strand sheating 4 stress-strain curves 23, 30 stress-strain diagrams 22 surface properties 26 temperatures (blow moulding) 40 temperatures (injection moulding) 34 – 36 tensile modulus 10 – 19, 20, 22 tensile strength 10 – 19, 20, 22, 36 thermal conductivity 28 thermal properties 27, 28 thermoplastic matrix 4 toughness 25, 26, 30 transfer moulding (Celstran) 38 transfer moulding (Compel) 42 turning 43 two-colour injection moulding 38

52

UL rating 31 ultrasonic welding 43, 44 vibration welding 43, 44 volume price 21 warpage tendency 36 water absorption 10 – 19 wear 26, 27 wear resistance 33 welding 43, 44 weld strength 43, 44

Celstran®

Compel®


11. Literature [1]

Lücke, A.: Thermoplaste mit Rückgrat. Kunststoffe 87 (1997) 3, p. 279 – 283

[7]

Wolf, H. J.: Personal communication from the DKI, Darmstadt

[2]

Lücke, A.: Eigenschaften und Anwendungen von langfaserverstärkten Thermoplasten. In: Zepf, H.-P. et al.: Faserverbundwerkstoffe mit thermoplastischer Matrix. Reihe Kontakt & Studium, vol. 529, ExpertVerlag, Eßlingen 1997

[8]

Thielen, M.: Starke Hohlkörper. Kunststoffe 84 (1994) 10, p. 1406 – 1412

[9]

Thomas, G.: Entwicklung kostengünstiger, serientauglicher Plastifizier- und Preßverfahren zur Herstellung von Strukturbauteilen aus anwendungsspezifisch entwickelten, unidirektional langfaserverstärkten Thermoplast-Granulaten. Abschlußbericht der Hoechst AG zum BMFT-Projekt 03 M 1055, Frankfurt 1996

[10]

Plastifizier-/Preßanlage – Verarbeitung thermoplastischer Kunststoffe im Strangablegeverfahren. Firmenschrift der Kannegießer KMH Kunststofftechnik GmbH, Minden 1997

[3]

Lücke, A.: Long Fiber Reinforced Thermoplastics in Cars. In: Handbuch zur 18th SAMPE Europe International Conference, Paris 1997

[4]

Pfeiffer, B.: Konstruktionswerkstoffe mit Edelstahlfasern gefüllt. In: Handbuch zum 7. Symposium Elektrisch leitende Kunststoffe, Technische Akademie Eßlingen 1997

[5]

Pfeiffer, B.: EMI-Shielding mit Edelstahlfilamenten. Plastverarbeiter (1997)

[6]

Dr. Edward M. Silverman: “Creep and Impact Resistance of Reinforced Thermoplastic: Long Fibers vs. Short Fibers” SPI/RPC 1985

10

11 53

Celstran®

Compel®


Important: Properties of molded parts can be influenced by a wide variety of factors involving material selection, further additives, part design, processing conditions and environmental exposure. It is the obligation of the customer to determine whether a particular material and part design is suitable for a particular application. The customer is responsible for evaluating the performance of all parts containing plastics prior to their commercialization. Our products are not intended for use in medical or dental implants. Unless provided otherwise, values shown

54

merely serve as an orientation; such values alone do not represent a sufficient basis for any part design. Our processing and other instructions must be followed. We do not hereby promise or guarantee specific properties of our products. Any existing industrial property rights must be observed. © Copyright by Ticona GmbH

Published in December 2000


Hostaform® POM Celcon® POM Duracon® POM Celanex® PBT Impet ® PET

Compel

®

Vandar® Thermoplastic polyester blends Riteflex® TPE-E Vectra® LCP

Celstran

®

Fortron® PPS Topas® COC Celstran® LFT Compel ® LFT GUR® PE-UHMW

Ticona GmbH Customer Service Europe D-65926 Frankfurt am Main Tel.: +49 (0) 69 - 3 05 -8 47 32 Fax: +49 (0) 69 - 3 05 -8 47 35

Technical Information Tel.: +1 - 8 00 - 6 33 - 48 22 Customer Service Tel.: +1 - 8 00 - 6 33 - 48 22

B 341 E BR-12.2000

Ticona 90 Morris Avenue Summit, NJ 07901 USA

Celstran - Hi Polymers

Recommend Documents