CH641482A5 - Thermoplastic elastomeric polymer mixture, and process for the preparation thereof - Google Patents

Description

The present invention relates to a thermoplastic elastomeric polymer mixture which contains polypropylene, a copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers and an ethylene homo- or copolymer, and a process for its preparation.

Polymer mixtures of this type are known from US Pat. No. 3,957,919. This patent describes that adding a small amount of polyethylene to a mixture consisting of polypropylene and ethylene-propylene copolymer can eliminate the negative influence of the crosslinking agents incorporated into the mixture, which decompose at the elevated temperature during the mixing. The resulting cross-linked mixtures have a particularly low melt index, so that they can almost not be processed using the injection molding process. US Pat. No. 3,919,358 discloses the preparation of mixtures of ethylene-propylene copolymers and polyethylene, the crystallinity of the ethylene-propylene copolymer being at least 10% and the density of the polyethylene being less than 0.94. However, these easily processable polymer mixtures have less good mechanical properties. In particular, the resistance to high temperatures and the impact resistance at low temperatures leave something to be desired. The permanent deformation, rigidity and hardness are also unsatisfactory. Furthermore, the production of mixtures of ethylene-propylene copolymer, polyethylene and an ethylene-vinyl acetate copolymer is known from US Pat. No. 3,941,859. In this case too, the crystallinity of the ethylene-propylene copolymer should be more than 10%. In the latter two patents, it is noted that low-crystallinity ethylene-propylene copolymer in mixtures with other polyolefins such as polyethylene cannot lead to good properties.

It has now been found that thermoplastic elastomeric polymer mixtures which contain polypropylene, a copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers and an ethylene homo or copolymer can be prepared, which are very easy to process and also good mechanical Possess properties. A mixture is made from:

A. 30 to 75 parts by weight of a crystalline, isotactic propylene homopolymer with a melt index between 1 and 25 dg / min and

B. 25 to 70 parts by weight of a rubbery copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers with a crystallinity of less than 10 wt .-%, an ethylene content of more than 58 wt .-%, a tensile strength of more than 30 kg / cm2 and a Mooney viscosity (ML [1 + 4] 125 ° C) of a minimum of 30 and a maximum of 90, whereby

C. a maximum of 15 parts of the propylene homopolymer and at least as many parts, as indicated by half the numerical value of the melt index of the propylene homopolymer, by as many parts by weight of ethylene homo- or copolymer with a density between 0.91 and 0.98 g / cm3 are replaced.

641 482

The polymer mixtures according to the invention have a melt index which is many times greater than the melt index of the mixtures obtained according to US Pat. No. 3,957,919, while the mechanical properties are at least equally good. The mixtures according to the invention are outstandingly suitable for injection molding processing. The combination of their properties (very good processability, high impact strength at low temperature, resistance to high temperatures, high rigidity) is extremely cheap, while the cost price is relatively low.

The invention basically consists of the fact that, through the correct choice of the individual components, a mixture with a surprising and extraordinarily attractive package of properties has been known to be produced. Contrary to the current state of the art, the use of a copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers with, among others, a. low crystallinity decided. The resulting shortcomings in relation to z. B. the rigidity and the resistance to high temperatures could be compensated for by using a propylene homopolymer. In order to eliminate the associated brittleness at low temperature, a small amount of ethylene homopolymer or copolymer, due to the melt index of the polypropylene, was added to the mixture. Furthermore, it was found that the copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers has to meet a number of other requirements in order to impart the desired, favorable combination of properties to the mixture according to the invention.

The copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers used according to the invention preferably has an ethylene content of at least 61% by weight. As is known, the tensile strength of these copolymers increases sharply with increasing ethylene content. However, especially with an ethylene content of more than 77% by weight, the crystallinity can increase considerably, which has an adverse effect on a number of properties, such as the compression set and toughness at low temperature. The ethylene content is therefore preferably chosen to be less than 77% by weight and in particular less than 75% by weight. Another advantage of this is the improvement in elongation at break. The best results are achieved if the ethylene content is chosen to be less than 70% by weight. Copolymers of ethylene, propylene and optionally one or more polyunsaturated monomers with a high molecular weight generally give mixtures with other polyolefins better mechanical properties, but at the same time reduce processability. Very good properties are found when the copolymer mentioned has a maximum Mooney viscosity (as a measure of the molecular weight), which is caused by the melt index of the propylene homopolymer. This preferred maximum value for the Mooney viscosity results from the equation

50

MLmax - 90 ——

m.i. 0.6

in the m.i. represents the melt index of polypropylene in dg / min, measured at 230 ° C and 2.16 kg. The Mooney viscosity (ML [1 + 4]) is measured at 125 ° C. The Mooney viscosity is preferably no higher than one derived from the equation

MLmax - 90 -

m.i. 0.6

3rd

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

641 482

Resulting value chosen because the processing properties are optimal in this case, while the other good properties are retained. For explanation, a table is included from which it is easy to read how large the preferred maximum value of the Mooney viscosity is for a given melt index of the propylene polymer.

Melt index preferred limit most preferred

Polypropylene limit dg / min

1

40

-

2nd

57

24th

3rd

64

38

4th

68

46

5

71

52

6

73

56

7

74

59

8th

76

61

9

77

63

10th

77

65

15

80

70

20th

82

73

25th

83

75

The copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers used according to the invention furthermore has a crystallinity of less than 10% by weight. An amorphous copolymer is preferably used, i. H. a copolymer with a crystallinity of at most 4% by weight and in particular of at most 1% by weight. This greatly improves the compression set and toughness at low temperatures. Furthermore, the rubber-like copolymer preferably has a tensile strength in the uncured state of more than 50 kg / cm 2. The crystallization temperature of the polymer, recorded by means of differential scanning calorimetry, is preferably above 0 ° C. and in particular above 10 ° C. The rubbery copolymer can contain one or more polyunsaturated monomers in an amount of preferably at most 20% by weight. These polyunsaturated monomers are normally non-conjugated polyenes, especially dienes. They are mostly used in amounts of up to 10% by weight. Examples of such monomers are dicyclopentadiene, alkylidene norbornene, alkenylnorbornene, alkadienes and cycloalkadienes. Dicyclopentadiene, ethyl-idennorbornene, norbornadiene, 1,5-hexadiene, 1,4-hexadiene and mixtures of these substances are preferably used. The rubbery copolymer used according to the invention can be prepared in a conventional manner, for. B. using the methods described in British Patent Specifications 1014873,941022 and 880 904. For further details on this preparation, reference is made to the unpublished Dutch patent application 7610672.

The crystalline, isotactic propylene homopolymer used according to the invention has a melt index between 1 and 25 dg / min and preferably between 1.5 and 20 dg / min. A melt index between 5 and 15 dg / min is particularly preferred. In the present invention, this melt index determines the preferred maximum value of the Mooney viscosity of the copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers and the amount of the ethylene homo- or copolymer to be added.

The density of the propylene homopolymer used is preferably between 0.900 and 0.910 g / cmJ.

In the non-prepublished Dutch patent application 7 610 672 it is described that an ethylene-propylene copolymer can be mixed with a specific propylene block-mixed polymer, which mixture has very good mechanical properties. With the aid of the method according to the present invention, these properties can be exceeded. Thus the products which are produced using the method according to the invention have better hardness, better tensile strength and better resistance to high temperatures than the mixture described in the aforementioned Dutch patent application. Other properties, such as toughness, remain at the same level. Other advantages are the better tensile strength and the lower thermal vibration. The high melt index, which can be achieved with the aid of the method according to the invention, is of particular importance. A polypropylene with a sufficiently high melt index must be used for this. This also improves the other mechanical properties. The brittleness at low temperature which is also caused thereby is surprisingly completely eliminated if a larger part of the polypropylene is replaced by ethylene homo- or copolymer, i.e. by an amount of ethylene homo- or copolymer, the numerical value of which is at least half, but preferably at least Vt, of the melt index of the polypropylene. It is very surprising that such greatly improved properties can be obtained by using a polypropylene homopolymer in combination with the correct amount of ethylene polymer.

The polypropylene used according to the present invention is basically isotactic and has a high crystallinity, preferably more than 50% by weight, measured by means of X-ray diffraction. It can be prepared using the well known methods, which are based primarily on the use of modified or unmodified titanium chloride, e.g. B. is activated with an aluminum compound. The third ingredient to be incorporated into the mixture according to the present invention is an ethylene polymer having a density between 0.91 and 0.98 g / cm 3 and preferably a melt index between 0.1 and 35 dg / min. The density is preferably greater than 0.94 g / cm3 and in particular greater than 0.96 g / cm3, which means that no or only a small amount of comonomer is incorporated into the ethylene polymer, e.g. B. less than 0.5 wt .-%.

A composition of 50 to 70 parts by weight of the crystalline, isotactic propylene homopolymer and 30 to 50 parts by weight of the rubbery copolymer is preferred for the thermoplastic elastomeric mixture according to the invention. When using undersize rubber-like copolymer, the special effects of the invention come into their own best. In this case, the rigidity and the properties at high temperature are at a high level. The improvement in the impact resistance at low temperature with the aid of the ethylene polymer is particularly pronounced, the processability in this composition is very good, while the other properties are also optimal.

The thermoplastic mixtures can be produced in a known manner using the apparatus customary for plastics, such as rollers, extruders, high-speed mixers and kneaders, the plastics material being subjected to shear forces at elevated temperature, in particular at a temperature between 150 and 220 ° C. Kneaders and extruders in which mixing takes place at temperatures of approximately 180 to 220 ° C. are preferred for use on an industrial scale.

All kinds of additives, such as dyes, lubricants,

4th

5

10th

15

20th

25th

30th

35

40

45

50

55

60

65

Fillers, antioxidants, UV stabilizers, flame retardants, zinc oxide and / or magnesium oxide, fibers or combinations of fibrous and powdery substances without losing their specific properties. In particular, soot and / or oil can be included in the mixture.

The polymer mixtures according to the invention can also be mixed with other polymers such as styrene polymers, polyamides, polyvinyl chloride, polycarbonates, block copolymers of styrene and butadiene, which may be hydrogenated, chlorinated polyolefins, such as chlorinated polyethylene, and mixtures of these polymers. They can also be used to improve the impact resistance of other polymers. The polymer mixtures according to the invention can be used for numerous purposes because they can be both soft and rubbery as well as stiff and impact-resistant. The mixtures are particularly suitable for the production of larger objects that are used outdoors, e.g. B. for automobile bumpers.

The invention therefore also relates to automobile parts which are produced from the polymer mixture according to the invention.

The thermoplastic elastomers produced according to the present invention are extremely weather-resistant. This weather resistance can be further improved by including UV stabilizers and / or zinc oxide in the mixture, especially if no carbon black is used, possibly in addition to a phenolic antioxidant. A combination of a so-called UV quencher, in particular a hindered amine, and a UV absorber, such as a benzotriazole and benzophenone compound, is preferably used as the UV stabilizer.

5,641,482

Example I

In a kneader, a series of mixtures of the composition 5 given in Table 1, consisting of ethylene-propylene polymer, polypropylene and possibly polyethylene, is produced. An ethylene-propylene terpolymer rubber, referred to as EPDMI, is used, which contains 64% ethylene, 30% propylene and 6% ethylidene norbornene. The tensile strength in the uncured state is 65 kg / cm2. The Mooney viscosity (ML [1 + 4] 125 ° C) is 52 and the 10 crystallinity is below 0.25%. The propylene polymer referred to as PPI is a block copolymer of propylene with 7% ethylene, a density of 0.905 and a melt index (230 ° C, 2.16 kg) of 6.0 dg / min. The propylene polymer referred to as PP II is a propylene homopolymer with a density of 0.905 g / cm3 and a melt index of 5.2 dg / min (230 ° C, 2.16 kg). The polyethylene designated PEI in the table has a density of 0.963 g / cm3 and a melt index of 8 dg / min (190 ° C, 2.16 kg).

To carry out the tests given in Table I, the rubber-like ethylene-propylene polymer is introduced into the kneader. After kneading for 1 minute, the polypropylene and the polyethylene are added. After 4 minutes of kneading (total time 5 minutes), kneading takes about 30 minutes without stamp printing; 25 then the kneading is continued until a temperature of approx. 170 ° C. is reached. Sheets are injected from the mixtures and tested for the properties specified in the table.

30 The table also shows the properties of two commercial products.

Table 1

Sample No.

Commercial

Commercial

1

2nd

3rd

4th

5

6

7

product A

product B

EPDM I

40

40

40

40

40

35

35

PPI

60

-

-

-

-

65

55

PPII

-

60

5TA

55

50

-

-

PEI

-

-

2 rooms

5

10th

-

10th

Melt index

(dg / min)

9.1

5.2

10.5

8.5

7.8

7.2

5.9

12.5

7.6

Hardness (shore D)

53

48

50

55

54

54

53

53

54

Vicat temp. 1 kg

97

100

105

127

122

118

107

119

103

(0 ° C)

«Heatsage test» (mm)

34.5

34.0

28.5

-

-

25.5

25.5

30th

Flat fall test

on flow seam

Breaking energy (Nm)

3.16

3.62

3.50

2.70

2.94

3.37

3.74

3.20

3.72

Force (N)

1329

1442

1404

1485

1468

1511

1474

1439

1438

Kind of break tough tough brittle brittle tough tough brittle brittle / tough

Tear resistance

71

61

69

77

78

76

75

70

73

The various properties are measured using the following standards:

Melt index hardness

Tensile strength Vicat temperature heat test Flat drop test

Tear resistance Thermal shrinkage

ASTM D-1238 (230 ° C, 5 kg)

ASTM D-2240 (reading after 3 seconds)

NEN 5602, test bar 3, elongation rate 15 cm / min

ASTM D-1525, load 1 kg

Test rod 10x1x0.16 cm, heat load for 1 min at 120 ° C

after 48 minutes of conditioning, weight 5 kg, drop height 1 m, impact speed 4.2 m / sec. The drop weight has a flat impact surface with a diameter of 1 cm. The test plate with a thickness of 1.6 mm is supported by a ring with a diameter of 2 cm DIN 53515

DIN 53497, thermal load 24 h at 90 ° C

641 482

The table shows that mixtures with PP homopolymer (samples 2, 3, 4, 5) are much better resistant to high temperatures than comparative sample 1 with PP copolymer. The resistance to high temperatures is also significantly better than that of the 2 comparable commercial products. Addition of PE is essential for the favorable combination of toughness at low temperature (high breaking energy, tough fracture) and good resistance to high temperatures. Samples 2, 3, 4 and 5 show that the PE content must be at least as high as is indicated by half the numerical value of the melt index of the PP homopolymer for adequate toughness at low temperature. Good resistance to high temperatures can also be achieved with a relatively high content of PP copolymer (sample 6), but in this case the toughness at low temperature is insufficient. The toughness at high temperature can be increased to an acceptable level by adding PE, but this has such an unfavorable effect on the resistance to high temperatures that the mixtures ultimately do not

10th

Show improvement compared to the commercial products (sample 7).

Example 2

The mixtures mentioned in Table 2 are produced in a laboratory kneader (Brabender plastograph) at a kneading chamber temperature of 180 ° C. and a kneading time of 10 minutes. All components of the mixture are brought into the kneading chamber at the same time. The mixtures are then rolled and pressed into sheets at 200 ° C. The components that make up the mixture have already been described in Example 1, with the exception of PP III, a PP homopolymer with a melt index of 1.3 dg / min and a density of 0.905 g / cm 3. Table 2 shows that samples 1 to 5 15 differ from samples 6 to 7 in that they have a higher hardness, greater rigidity at room temperature, greater tensile strength and higher tensile strength. From these facts it follows that blends with a PP homopolymer have better mechanical properties than 20 blends with a PP copolymer.

Table 2

Sample No.

1

2nd

3rd

4th

5

6

7

EPDM I

47! 4

45

40

47 / i

45

4714

45

PPI

-

-

-

-

-

50

50

PPII

50

50

50

-

-

-

-

PP III

-

-

-

50

50

-

-

PEI

214

5

10th

214

5

214

5

Melt index (190 ° C-10 kg) g / min

1.0

1.2

1.3

0.46

0.49

1.3

1.6

Hardness (shore D)

51

52

53

51

53

46

47

G'xlO "9 (Dyne / cm2)

2.30

2.43

2.69

2.13

2.39

1.39

1.45

Tensile strength (N / mm)

73

83

84

83

83

57

61

Tensile strength (MPa)

9.9

10.0

10.6

9.8

10.9

7.4

6.1

Elongation at break (%)

160

150

100

270

290

300

280

The properties are measured according to the following standards or methods:

Melt index hardness

Stiffness (G ')

Tear resistance

tensile strenght

ASTM D-1228 (190 ° C, 10 kg)

ASTM D-2240, reading after 3 sec torsion damping f = 0.2 H2, 22 ° C DIN 53515

NEN 5602, test bar 2, elongation rate 30 cm / min

Example 3

This example shows that the Mooney viscosity of the ethylene-propylene copolymer has a maximum value due to the melt index of the PP homopolymer in order to enable problem-free processing using injection molding techniques.

40 parts by weight are made in a Brabender plastograph. Ethylene propylene terpolymer (EPDM), 55 parts by weight. PP homopolymer and 5 parts by weight. Low pressure polyethylene mechanically mixed together in the manner described in Example 2. In the 9 mixtures, both the Mooney

50

Viscosity of the EPDM varies like the melt index of the EPDM and the melt index of the PP homopolymer. Three ethylene-propylene terpolymers with a Mooney viscosity (MLW [1 + 4] 125 ° C) of 39.52 or 62 are each mixed with three types of PP homopolymer with a melt index of 1.3.5.2 or 9.5 dg / min (230 ° C, 5 kg). The melt indexes of the mixtures are given in Table 3. For the mixtures 55 examined, the preferably used maximum value of the Mooney viscosity of the EPDM as a function of the melt index of the PP homopolymer is as follows:

Melting index PP homopolymer (dg / min)

Maximum Mooney viscosity of the EPDM

50

MLMAX = 90 ——

preferred maximum limit of the Mooney viscosity of the EPDM 100

MW - 90 ——

m.i. ""O

1.3 3.2 9.5

47 71 77

preferably do not use

53

64

Table 3 shows that the Mooney viscosity of EPDM in samples 6 and 9 is greater than the preferred maximum value. These samples have a melt index that is too low for good processing. The remaining samples have a sufficiently low Mooney plasticity and consequently

7,641,482

the mixtures have such a melt index that good processability is guaranteed. Optimal processability is found in samples 1, 2, 4 and 7. The processability of samples 3 and 8 will not be sufficient 5 for critical applications.

Table 3

Sample No.

1

2nd

3rd

4th

5

6

7

8th

9

Mooney viscosity EPDM MLW (1 + 4) 125 ° C

39

39

39

52

52

52

62

62

62

Melting index PP homopolymer

230 ° C / 2.16 kg (dg / min)

9.5

5.2

1.3

9.5

5.2

1.3

9.5

5.2

1.3

Composition of the mixture

EPDM II *

40

40

40

-

-

-

-

-

-

EPDM I

-

-

-

40

40

40

-

-

_

EPDM III *

-

-

-

-

-

-

40

40

40

PPIV *

55

-

-

55

-

-

55

-

-

PP II

-

55

-

-

55

-

-

55

-

PP III

-

55

-

-

55

-

-

55

PEI

5

5

5

5

5

5

5

5

5

Melt index 230 ° C / 5 kg (dg / min)

14.5

9.9

4.52

11.2

7.83

3.51

8.2

5.92

2.7 *

* EPDM II: 63% by weight of ethylene, 5% by weight of ethylidene. Tensile strength 49 kg / cm2, crystallinity> 0.25%. DSC temperature

+ 7 ° C

EPDM III: 62% by weight of ethylene, 5% by weight of ethylidene. Tensile strength 55 kg / cm2, crystallinity> 0.25%. DSC temperature

+ 8 ° C

PP IV: polypropylene homopolymer melt index (230 ° C / 2.16 kg) 9.5 dg / min. Density 0.905 g / cm3

1. Poor processability in the injection molding process.

2. Unsuitable for critical applications where good processability is required.

3. Processability just good enough for injection molding complex mold parts.

Example 4

Table 4 shows that even with a propylene-40 homopolymer with a melt index of 9.5 dg / min, mixtures can be produced which have high toughness at low temperature. To do this, it is necessary that the amount of PE is at least about 5% by weight, i.e. more than half of the numerical value of the melt index of the 45 PP homopolymer is indicated.

Table 4

Sample No.

1

2nd

3rd

4th

composition

EPDM I

40

40

40

40

PP IV

60

57 / i

55

50

PEI

-

2/2

5

10th

properties

Melt index 230 ° C / 5 kg (dg / min)

14.3

12.4

10.0

7.8

Hardness (Shore D)

56

56

56

54

Tensile strength [DIN 53515 (N / mm)]

83

82

80

80

Instrumented flat fall test (—40 ° C)

on flow seam fracture energy (Nm)

3.2

3.7

3.9

4.1

- Max. Force (N)

1622

1616

1616

1609

- Type of break brittle brittle brittle tough

Yield stress (N / mm2)

18.1

19.1

17.1

17.1

Drawing tension (N / mm2)

15.6

16.6

15.7

15.2

Tensile strength (N / mm2)

20.2

19.6

19.6

19.6

Elongation at break (%)

470

450

470

440

The mixtures listed in Table 4 with a polypropylene homopolymer having a melt index of 9.5 dg / min were prepared in the manner described in Example 1. However, the samples are processed under different conditions, e.g. H. sprayed into plates at higher temperature and lower pressure. As a result, the test results are not entirely comparable with those of the previous examples.

641 482

8th

Example 5

This example shows that the advantages of adding polyethylene described in the invention are canceled out by an excessively high polyethylene content. The mixtures mentioned in Table 5 are prepared in the kneader in the manner described in Example 1. Samples 1, 2 and 3 are all easy to process, mixture 4 with 20% by weight PE has a high polyethylene content and has a melt index that is too low. The tensile strength is also unsatisfactory.

Example 6

In this example it is shown that the density of the polyethylene can also be important for the effectiveness of the polyethylene as a means of improving the mechanical properties. In a kneader, 40 tie. EPDM 1.55Tle. PP 1 and 5 tie. Polyethylene mechanically mixed together in the manner described in Example 1.

The following PE types are used in the 5 mixtures:

Table 5

Sample No.

1

2nd

3rd

4th

EPDM I

35

35

35

35

PP II

62 /.

60

55

45

PEI

2

5

10th

20th

Melt index (dg / min) 10.1

9.0

7.2

2.5

Hardness (Shore D)

57

7

56

56

Tensile strength (N / mm2) 12.9

12.5

11.4

9.8

Elongation at break (%)

175

255

250

250

Vicat temperature

125

123

119

110

15

density

Melt index (190 ° C, 2.16 kg) (dg / min)

PEI

0.963 g / cm3

8th

PEU

0.953

24th

Pein

0.948

0.3

PE IV

0.953

1.4

PE V (LDPE)

0.918

7.5

25th

The samples are sprayed into plates in order to determine their properties in the manner described in Example 4. These properties are given in Table 6.

Table 6

Sample No. 1 2 3 4 5

composition

EPDM I 40 40 40 40 40

PP II 55 55 55 55 55

PE I 5 - - - -

PE II 5

PE III 5

PE IV 5

PEV (LDPE) 5

properties

Melt index 230 ° C / 5 kg (dg / min)

5.2

5.9

5.5

5.3

5.7

Hardness (Shore D)

54

53

54

54

53

Tear resistance DIN 53515 (N / mm)

75

73

75

74

74

Instrumented flat fall test (- ■ 40 ° C)

on flow seam fracture energy (NM)

4.0

4.2

4.0

4.2

3.9

- Max. Force (N)

1649

1623

1639

1631

1586

- Break type tough tough tough tough tough

Yield stress (N / mm2)

18.4

17.8

18.5

18.3

17.6

Drawing tension (N / mm2)

17.0

16.0

17.0

16.6

16.5

Tensile strength (N / mm2)

21.3

21.6

21.1

20.9

21.0

Elongation at break {%)

430

420

430

420

420

Table 6 shows that 4 mixtures are made when using polyethylene. In 3 mixtures «green-len with a density of more than 0.94 g / cm3 better results strength» -EPDM types are used. For the properties of being achieved. The best combinations of properties 60 mixtures are shown in Table 7.

are found at a density of more than 0.96 g / cm3. The table shows that the mixture with not

“Green strength” EPDM (sample 1) differs from the mixtures with example 7 “green strength” EPDM (samples 2, 3 and 4) by a low

In the manner described in Example 2, hardness, tensile strength and tensile strength are differentiated in the Brabenre. der-plastograph mixtures of 40 parts by weight. Ethylene propylene 65 To the advantages described in the present invention len terpolymer, 55 parts by weight. To be able to make full use of propylene homopolymer is therefore a «green and 5 parts by weight. Made of polyethylene. Then strength »EPDM will be required. High ethylene contents lead to the mixtures being rolled and pressed into sheets at 200 ° C. It has lower elongation at break (sample 3).

9

641 482

Table 7

Sample No.

1

2nd

3rd

4th

composition

EPDM IV1 '

40

-

-

-

EPDM I

-

40

-

-

EPDM V2)

-

-

40

-

EPDM VI3)

-

-

-

40

PP II

55

55

55

55

PEI

5

5

5

5

Properties2 '

Melt index

230 ° C / 5 kg (dg / min)

7.3

7.8

6.5

5.6

Hardness (Shore D)

49

55

55

55

Table 7

Sample No.

1

2nd

3rd

4th

DIN 53515 (N / mm)

75

89

99

95

Tensile strength (N / mm2)

10.4

11.9

12.6

12.4

Elongation at break (%)

110

130

80

130

1) EPDMIV: ethylene content 55% by weight, ethylidene norbornene 10 5% by weight, tensile strength 2.4 kg / cm2, crystallinity> 0.25%,

Mooney ML (1 + 4) 125 ° C: 54, DSC temperature-17 ° C

2) EPDM V: ethylene content 75% by weight, hexadiene-1,4

3% tensile strength 124kg / cm2, crystallinity 8%, Mooney ML (1 + 4) 125 ° C: 64, DSC temperature + 38 ° C 15 3) EPDM VI: ethylene content 70% by weight, ethylidene norbornene 4.5% .-%, tensile strength 120 kg / cm2, crystallinity 3%, Mooney ML (1 + 4) 125 ° C: 61, DSC temperature + 24 ° C

M

Claims (20)

641 482 PATENT CLAIMS 1. Thermoplastic elastomeric polymer mixture containing polypropylene, a copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers and an ethylene homo- or copolymer, characterized in that it contains a mixture of: A. 30 to 75 parts by weight of a crystalline, isotactic propylene homopolymer with a melt index between 1 and 25 dg / min and B. 25 to 70 parts by weight of a rubber-like copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers with a crystallinity of less than 10 wt .-%, an ethylene content of more than 58 wt .-%, a tensile strength of more than 30 kg / cm2 and a Mooney viscosity (ML [1 + 4] 125 ° C) as a measure of the molecular weight, which is at least 30 and a maximum of 90, wherein C. a maximum of 15 parts by weight of the propylene homopolymer and at least as many parts as indicated by half the numerical value of the melt index of the propylene homopolymer, by as many parts by weight of ethylene homo- or copolymer with a density between 0.91 -103 and 0.98 -103 kg / m3 are replaced. 2. Polymer mixture according to claim 1, characterized in that the maximum Mooney viscosity of the rubbery copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers from the equation 50 MLmax - 90 ——— m.i. results, where m.i. represents the melt index of the propylene polymer used. 3. Polymer mixture according to claim 2, characterized in that the maximum Mooney viscosity from the equation 100 MLmax - 90 —— m.i. 0.6 results. 4. Polymer mixture according to one of claims 1 to 3, characterized in that it contains a mixture of: A. 50 to 70 parts by weight of a crystalline, isotactic propylene homopolymer with a melt index between 1 and 25 dg / min and B. 30 to 50 parts by weight of a rubbery copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers with a crystallinity of less than 10 wt .-%, an ethylene content of more than 58 wt .-%, a tensile strength of more than 30 kg / cm2 and a Mooney viscosity (ML [1 + 4] 125 ° C) as a measure of the molecular weight, which is at least 30 and a maximum of 90, where C. a maximum of 15 parts by weight of the propylene homopolymer and at least as many parts as indicated by half the numerical value of the melt index of the propylene homopolymer, by as many parts by weight of ethylene homo- or copolymer with a density between 0.91-103 kg / m3 and 0.98-103 kg / m3 are replaced. 5 5. Polymer mixture according to one of claims 1 to 4, characterized in that the minimum number of parts by weight of propylene homopolymer, which are replaced by ethylene homo- or copolymer, / the numerical value of the melt index of the propylene polymer. 6. Polymer mixture according to one of claims 1 to 5, characterized in that the rubbery copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers has an ethylene content of at least 61% by weight. 7. polymer mixture according to claim 6, characterized in that the rubber-like copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers contains a maximum of 77% by weight, preferably a maximum of 75% by weight and in particular a maximum of 70% by weight of ethylene . 8. Polymer mixture according to one of claims 7, characterized in that the rubber-like copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers has a crystallinity of at most 4% by weight and in particular of at most 1% by weight. 9. Polymer mixture according to one of claims 1 to 8, characterized in that the rubber-like copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers has a tensile strength of more than 50 kg / cm2. 10th 10. Polymer mixture according to one of claims 1 to 9, characterized in that the copolymer of ethylene and propylene contains one or more polyunsaturated monomers in a quantity of at most 20 wt .-% and in particular of at most 10 wt .-% copolymerized. 11. Polymer mixture according to claim 10, characterized in that a polyunsaturated monomer from the group of dicyclopentadiene, ethylidene norbornene, 1,4-hexadiene, 1,5-hexadiene and norbornadiene is polymerized. 12. Polymer mixture according to one of claims 1 to 11, characterized in that the crystalline propylene homopolymer has a melt index between 1.5 and 20 dg / min and preferably between 5 and 15 dg / min. 13. Polymer mixture according to one of claims 1 to 12, characterized in that the propylene homopolymer has a density between 0.900-103 and 0.910-103 kg / m3. 14. Polymer mixture according to one of claims 1 to 13, characterized in that the density of the ethylene homo- or copolymer is more than 0.94-103 kg / m3. 15 20th 25th 30th 35 40 45 50 55 60 65 is given, are replaced by as many parts by weight of ethylene homo- or copolymer with a density between 0.91 • 103 and 0.98-103 kg / m3, mixed. 15. Polymer mixture according to one of claims 1 to 14, characterized in that the density of the ethylene homo- or copolymer is more than 0.96-103 kg / m3. 16. Polymer mixture according to one of claims 1 to 15, characterized in that the ethylene homo- or copolymer has a melt index between 0.1 and 35 dg / min and preferably between 1 and 25 dg / min. 17. Polymer mixture according to one of claims 1 to 16, characterized in that the ethylene polymer contains a maximum of 0.5 wt .-% comonomer in copolymerized form. 18. A method for producing a thermoplastic elastomeric polymer mixture according to claim 1, characterized in that A. 30 to 75 parts by weight of a crystalline, isotactic propylene homopolymer with a melt index between 1 and 25 dg / min and B. 25 to 70 parts by weight of a rubbery copolymer of ethylene, propylene and optionally one or more polyunsaturated monomers with a crystallinity of less than 10 wt .-%, an ethylene content of more than 58 wt .-%, a tensile strength of more than 30 kg / cm2 and a Mooney viscosity (ML [1 + 4] 125 ° C) as a measure of the molecular weight, which is at least 30 and a maximum of 90, wherein C. a maximum of 15 parts by weight of the propylene homopolymer and at least as many parts as by half the numerical value of the melt index of the propylene homopolymer2 19. The method according to claim 18 for the preparation of a polymer mixture according to one of claims 2 to 17. 20. Automobile parts made from a polymer mixture according to claim 1.