DE925314C - Process for the production of elastomer-resin mixtures - Google Patents

Description

The invention relates to improved elastomer-synthetic resin mixtures, made by mixing various inelastic, resinous, thermoplastic Synthetic resins (A) (e.g. copolymers of styrene and acrylonitrile, polyvinyl chloride or copolymers with a larger proportion of vinyl chloride and "a small one Proportion of vinyl acetate) with a mixture of two elastomeric materials, the greater proportion of which (B) a rubbery butadiene-acrylonitrile polymerization product and its smaller portion (C) either a rubber-like homopolymer of i, 3-butadiene or a homologue or a halogenated analog thereof, or a rubber-like copolymer of a larger one Amount of i, 3-butadiene or a homologue thereof with a smaller amount of styrene, Methyl methacrylate or a monovinyl pyridine. It is known that valuable products with noteworthy Ordinary temperature toughness can be produced by certain hard, thermoplastic resins with rubber-like butadiene-acrylonitrile copolymers mixes. Such mixtures have a tendency to react at low temperatures, e.g. B. at o ° or below becoming brittle because of the rubbery butadiene-acrylonitrile component becomes stiff or brittle. This tendency of the elastomeric phase to become brittle, can be somewhat diminished by the fact that the

The proportion of acrylonitrile in the elastomer is reduced will. However, improvement of this kind is limited because of butadiene-acrylonitrile rubbers low acrylonitrile does not mix well with the normally tough thermoplastic Mixing resins with the result that it adversely affects the quality of the product becomes, as shown by the decreased toughness or impact resistance at ordinary temperatures, ίο It is also known that the products, which by mixing hard, inelastic, thermoplastic Resin, e.g. B. polyvinyl chloride,. or a resinous styrene-acrylonitrile copolymer with elastomers which do not have acrylonitrile, poor physical ones are obtained Show properties at all temperatures and are not useful products.

It is finally known that the problem of poor physical properties at low temperatures showing thermoplastic, resinous mixtures by adding a liquid plasticizer can be solved. However, this affects the physical properties at elevated temperatures unfavorable and is therefore avoided. . - "

The invention achieves the object shown above without the aid of liquid plasticizers and without reducing the content of acrylonitrile in the butadiene-acrylonitrile elastomer.

It has been found that by replacing a small part of the rubber-like butadiene-acrylonitrile copolymer in the elastomer-resin mixtures of the type described above by an elastomer which is not acrylonitrile contains and which mainly consists of a rubbery homopolymer of butadiene consists or of a halogenated analog or a homologue thereof or of rubber-like copolymers of butadiene or a homologue thereof with a low Proportion of styrene, methyl methacrylate or a monovinylpyridine, products "are obtained, which have much greater toughness, especially at low temperatures, e.g. B \ at o ° (measured due to the impact resistance at such temperatures), without any noticeable reduction in the Properties at normal temperatures.

In practicing the invention there will be three in the usual manner. Basic ingredients (A, B, C) mixed homogeneously.

Component A is a normally hard, inelastic, resinous, thermoplastic material from a copolymer with 50 to 90 percent by weight styrene and 50 to 10 percent by weight Acrylonitrile or from polyvinyl chloride, in particular / polyvinyl chloride, or from a Mixed polymer with a larger proportion of vinyl chloride and a smaller proportion of vinyl acetate. At this component has an elongation at break of less than 5% and is hard, tough and brittle ordinary room temperature and has no rubber-like properties at all.

Component B. the. Mixtures is a commercially available, rubber-shaped copolymer of butadiene and acrylonitrile, also known as nitrile rubber. Usually this ingredient contains 20 to 40 "Io acrylonitrile with the remainder being butadiene. The usual, commercially available material which has little or no content of gel insoluble in methyl ethyl ketone can be used nitrile a Acrylsäurenitrilgehalt from 26 to 40 ° / o. one can also rubber-like butadiene-acrylonitrile copolymers use which contain significant amounts of gel which is insoluble in methyl ethyl ketone and which has a swelling value of 8 to "35 ¹ in methyl ethyl ketone. Those elastomers are preferably used which have 50% or more of gel which is insoluble in methyl ethyl ketone and which has the aforementioned swelling value. In general, the acrylonitrile content of such chewable copolymers is from 20 to 26%, the remainder being butadiene.

Component C of the new mixtures does not give the resinous polymer A alone usable product. It was completely surprising to find that the replacement of a small proportion of constituent B by such constituent C the properties of the mixture of A and B significantly 'improved, although when using component C instead of the entire amount of Ingredient B would result in a completely worthless product.

Component C is either a rubber homopolymer of 1,3-butadiene or a homologue thereof which has no more than 8 carbon atoms, e.g. B. isoprene or a chlorinated analog thereof which has no more than 8 carbon atoms, e.g. B. 2-chloro-i, 3-butadiene. On the other hand, the component C can be a rubber-like copolymer made of a larger proportion of i, 3-butadiene or a homologue thereof which has no more than 8 carbon atoms, and a minor proportion of styrene, methyl methacrylate or a monovmiylpyridine, e.g. B. 2-vinylpyridine, 4-vinylpyridine, 2-ethyl-5-vinylpyridine or 5-ethyl-2-vinylpyridime. N is ₀ in general, such copolymers contain 60 to 90? / O butadiene and 40 to 10 ° / o of the other monomeric material.

Rubbery polybutadiene and. rubber-like copolymers of butadiene and styrene, which contain up to 10% styrene are included in the practice of the invention C preferred.

Rubberized polybutadiene makes the best Results at low temperatures. Butadiene-styrene copolymer is not as good as rubbery polybutadiene, but it is lighter to be edited. A rubber which is a rubber-shaped copolymer is preferred from 5 to 10% styrene and 95 to 90% butadiene is; it gives essentially just as good results

like those obtained with polybutadiene and is easier to get commercially.

Examples of polyisoprenes used as component C in the practice of the invention are synthetic polyisoprenes and natural rubber, especially Hevea rubber, z. B. light crepe rubber.

The extent of this replacement of the nitrile rubber component B of the mixture according to the invention by the constituent C can be between 2 and 35 percent by weight of the sum of B and C, preferably between 4 and 16 0/0.

The proportions of the resinous component A and the elastomeric components B and C can be between 50 and 90% for A fluctuate and accordingly between 50 and 10% for B + C. These Percentages are percentages by weight, based on the sum of A, B and C. -

In the following examples, the hard thermoplastic resin component A is used as the primary Component, the rubber-like butadiene-acrylonitrile copolymer - component "B" as secondary component, and the butadiene type elastomer which does not contain acrylonitrile, component C is addressed as a tertiary component. The well-known mixtures of resin and butadiene-acrylonitrile elastomers are referred to as binary blends. Mixtures of Resin and two different elastomers, e.g. B. those which also encompasses the present invention, are called ternary mixtures. All percentages and ratios are based on Weight.

Example I.

In this example, the primary component is a resinous styrene-acrylonitrile copolymer, produced by emulsion polymerization, which contains 27% acrylonitrile. The secondary component is a rubber-like butadiene-acrylonitrile copolymer which contains 23% acrylonitrile and has a Mooney viscosity at 100 ° of 52, a content of 72% of gel insoluble in methyl ethyl ketone and a swelling value for the gel of 11, measured in methyl ethyl ketone. The tertiary component is as shown in Table I. All mixtures below were prepared in a roll mill, which was heated to 149-163 ^0, the following proportions have been applied:

Primary component (resin) (A) .... 75 parts secondary component (nitrile

tertiary component *) (C) 2 -

Stabilizer and anti-oxidant

Middle '.. ι part

Titanium dioxide 15 parts

'

total .... 116 parts

*) One of the components listed in Table I The notched impact strength was measured in a Tinius-Olsen impact test apparatus the pendulum type measured using a 0.635cm x i ^ cm pattern, notched according to the ASTM method D 256-47 T (published in Tentative Methods of Test for Impact Resistance of Plaktics and Electrical Insulating Materials, ASTM. Designation: D 256-47 T, Issued, 1941; Revised, 1943, 1947, pp. 3i2ff.).

For comparison, a control sample A was produced with the omission of the tertiary component and using the proportions just given with the exception that 25 instead of 23 parts of the secondary component were used.

The results given in Table I show that the effect of a diene homopolymer (B, C, D, E) as a tertiary component in the ternary mixture results in a substantial improvement the impact resistance shows, at low temperatures without significant reduction in the Toughness or hardness under normal test conditions. The use of a rubber-like diene copolymer However, (F, G, H) as a tertiary component does not give similar results clear. The use of a non-diene elastomer (I, J, K) as the tertiary component causes either no improvement in low temperature shock resistance or it decreases and lies outside the present invention.

Table I.

Tertiary component
the ternary mix

A no tertiary component
Diene homopolymers:

B polybutadiene

C polychlorobutadiene

D polyisoprene (synthetic).
E natural rubber (lighter
Crepe rubber)

Diene copolymers:
F butadiene-2-vinyl pyridine

75: 25 · ■ ·. 57.1

G butadiene methyl metha-

acrylate 65: 35 63.1

H butadiene-styrene 75; 25 ... 60.4

Non-diene elastomers:
I butyl rubber (low temperature copolymer
from 80 to 99% isobutylene
and 20 to 1% isoprene) .. 56.0

J ethylene polysulfide 50.0

K mixed polymer of 95%
• ethyl acrylate and 5 ° / ₀
2-chloroethyl vinyl ether .. 58.8

*) - ASTM regulation D 256-47 T
**) ASTM regulation D 785-48 T.

Notched impact resistance

cmkg / cm *) measured at

25 ° I o °

68.0

57.1 66.9

56.5 57.7

29.4

44.1 45.7 48.4

47.3

38, i

40.8 35.4

29.4 18.0

24.5

92

91 93 92

92

91

94 92

Rockwell hardness R scale **) at 25 ⁰

92

96

93

Example II

In this example the primary component is a resinous styrene-acrylonitrile polymer, which contains 26% acrylonitrile, the secondary component is a rubber-like butadiene-acrylonitrile copolymer, identical to that which is always used in Example I, and the tertiary component is a rubbery one Polybutadiene, the proportions of the secondary and tertiary components fluctuating, as in Table given. Only the mixtures M, N and O are examples according to the invention.

Table II

mixing ratio

Resin (primary component) (A)

secondary component (B)
tertiary component
(Polybutadiene) (C) .....

Notched impact resistance
cmkg / cm

at 25 ⁰

at o °

at - 20 °

75 25

52.8

15.8

2.2

75 24

63.6

48.4. 26.1

75 21

53.3 43.5 28.8

75 17

33.7 27.7 22.3 The example shows the replacement of up to about one third of the secondary component with polybutadiene, thereby achieving approximately a ten fold improvement in low temperature impact strength will. The most favorable effect is found when the tertiary component in amounts of 4 to 16% of the total elastomer used is present.

Example III

In this series of tests, the primary component consists of a styrene-acrylonitrile resin, containing 24% acrylonitrile. Various butadiene-acrylonitrile rubbers are used as secondary components are used which contain 50 to 75% of gel insoluble in methyl ethyl ketone and have acrylonitrile contents as shown. The tertiary component is rubbery polybutadiene. The mixtures contain other ingredients in amounts as described in Example I. In this series of tests, only the mixtures Q and S examples according to the invention. The nitrile rubber used in mixtures P and Q has a gel content of 74%, a gel swell value of 19 and a Mooney viscosity at 100 ° of 8o, while in the case of mixtures R and S the gel content was 71%, with a swelling value of 20 and a Mooney value of 60.

This example shows that the increase in toughness obtained by replacing a part

Table III

Mixed ratio

P. Q K. S. 70 70 70 70 30th
O 28
.2 30th
0 28
2 26.3 26.3 23.0 23.0 26.3 24.5 23.0 21.5 69.1
■ 57.1
9.2 69.6
64.7
23.4 72.4
47.9
12.5 70.2
62.6
48.4

Weight fraction of resin (A)

Percentage by weight of butadiene-acrylonitrile-poly

merisat (B)

Weight fraction of polybutadiene (C)

Acrylonitrile content of the butadiene-acrylonitrile

Polymer

Acrylonitrile content of the ternary elastomer mixture

Notched impact resistance cmkg / cm

at 25 ⁰

at 0 ° '.

at - 20 °

70

30 ο

19.8 19.8

38.1

42.4 20.7

of the rubbery butadiene-acrylic acid copolymer is much larger due to polybutadiene is, as one can only from the reduction of the acrylonitrile content of the elastomer phase could assume by dilution.

That is, in the binary series P, R, T only occurs a slight increase in the low-temperature shock resistance with a reduction in the acrylonitrile content one versus the ternary mixtures Q, S of the invention. ■ -

Example IV

In this example, the primary component is a commercially available polyvinyl chloride, the secondary The component is a commercially available, rubber-like butadiene-acrylonitrile copolymer, which has an acrylonitrile content of 26% and no gel insoluble in methyl ethyl ketone, the tertiary component is a rubbery polybutadiene.

Table IV

mixing ratio

Polyvinyl chloride

rubber-like butadiene-acrylonitrile mixed poly-
merisat

Polybutadiene

Lead carbonate

Antioxidants

Titanium dioxide

Notched impact resistance cmkg / cm at 25 ° ..
at o ° ..
at -20 °

85.0

I5, o 0.0 2.6 0.6

15.0

84.3 86.0 27.2

33.3

This example shows that the addition of the tertiary component to a binary mixture, which contains polyvinyl chloride, improves the toughness at low temperature according to the invention. The replacement of the polyvinyl chloride in Example IV by a copolymer of 85 to 95% vinyl chloride and 15 to 5% vinyl acetate gives similar ones Results.

Example V

In this example the primary component is a styrene-acrylonitrile resin, the 29% acrylonitrile contains. The secondary component is a rubber-like butadiene-acrylic acid tril copolymer, identical to that used in Mixtures P and Q in Example IV, and the tertiary component is a rubbery one Polybutadiene. The variables involved are the proportions of resin and elastomers; other ingredients are present as in Example I. Mixes X, Z and only AB are within the invention.

Table V

mixing ratio

W. X Y Z "AA 70.0 70.0 75.0 75.0 8o, O 30.0 27.6 25.0 23.0 20.0 0.0 2.4 0.0 2.0 0.0 51.1 60.3 29.4 44, i 17.4

AWAY

Primary component (A)

secondary component (B)
tertiary component (C)

Notched. Impact resistance cmkg / cm at o °

80.0

18.4

1.6

23.9

In any case, this example shows that the tertiary component acts to increase toughness to enlarge low temperatures beyond the range that can be obtained by resin and elastomers is.

Example VI

In this example is the primary component

a resinous styrene-acrylonitrile copolymer with a composition as shown the secondary component is a rubber-like butadiene-acrylonitrile copolymer with a content of acrylonitrile and gel, weldies is insoluble in methyl ethyl ketone, as stated, the tertiary component is a rubbery component Polybutadiene. The secondary component used in the AG and AH blends has a Mooney value at 100 ° of 54 and a swelling value of its gel content of 16.

Otherwise, all of the mixtures were prepared as described in Example I.

Table VI

mixing ratio

AD

AE

AF

AG

AH

Acrylonitrile content:

the primary component (A)

the secondary component (B)

Gel content of the secondary component (B)

Parts by weight:

Primary component (resin) (A)

secondary component (elastomers) (B). tertiary component (polybutadiene) (C) ..

Notched impact resistance cmkg / cm

at 25 °

at o °

33%

40%

0%

75

23

18.0
6.5

27%

32%

0%

75

25th

18.5
6.5

27%

32%

0%

37-5

20% 20%

70%

75

25th

39-7

20% 20% 70%

75

23

51.1 46.8

This example shows that the tertiary component works in combination with resins and butadiene-acrylonitrile rubbers, which can vary within a wide range of mixtures. While the preceding examples show the use of styrene-acrylonitrile resins which have acrylonitrile contents in the range from 20 to 33%, resins outside this range can also be used in accordance with the invention, e.g. B. from 10 to 20 ^fl / o and from 33 to 40% acrylonitrile content. While the examples show a variation of the resin from 70 to 85% and the elastomer content fluctuates between 30 and 15%, resin-elastomer mixtures outside this range, e.g. B. those which 50 to 70% and those which contain 85 to 90% resin are used within the scope of the invention. In addition, since the examples show on the one hand nitrile rubber with little or no gel and 26 to 40% acrylonitrile and on the other hand nitrile rubber with 50 to 75% of gel insoluble in methyl ethyl ketone and 20 to 26% acrylonitrile, rubber can be used according to the invention which contains little or no gel and furthermore 20 to 26% acrylonitrile, or nitrile rubber with 26 to 40% acrylonitrile and with a high content, e.g. B. 50 to 75% on the above-mentioned gel which is insoluble in methyl ethyl ketone.

From the foregoing it can be seen that the invention is simple, economical, very effective Method represents the impact resistance of elastomer-resin mixtures at low temperatures to be greatly improved, especially of mixtures of nitrile rubber with resinous ones Styrene-acrylonitrile copolymers. It can also be seen that the present invention without Application of significant expense for mixing can be applied; it is possible to use the ingredients to mix the mixture according to the invention intimately with one another in the same way as this has been done according to the prior art to generally similar elastomer-resin blends to manufacture. It is also seen that the practice of the invention affects the properties of the blends Room temperature changed to no noticeable extent.

Claims (3)

PATENT CLAIMS: ι. Process for the production of elastomer-resin mixtures, characterized in that a normally inelastic, resinous, thermoplastic material (A) made from copolymers of 50 to 90% styrene and 50 to 10% acrylonitrile, Polyvinyl chloride or copolymers made from a larger proportion of vinyl chloride and one smaller proportion of vinyl acetate with a rubber-like copolymer (B) made of 3-butadiene and acrylonitrile, further mixed with a rubbery polymeric material (C), consisting of rubber-like homopolymers of i, 3-butadiene, its homologues or halogenated Analogous to or consisting of rubber-like copolymers made from a larger proportion of 1,3-butadiene or its homologues with a smaller proportion of styrene, methyl methacrylate or a monovinyl pyridine, where the weight ratios of A, B and C are such that A is between 50 and "90 ^ / 0 the sum of A, B and C and C between 2 and 35%, preferably between 4 and 16%, the sum of B and C fluctuates. 2. The method according to claim 1, characterized in that that G is a rubber-like copolymer of 90 to 95% 1, 3-butadiene and Is 10 to 5% styrene. © 9602 3rd SS