DE2221094C3 - oil-resistant polymer composition - Google Patents

Description

22nd

merisats (1) is less than 5 parts by weight does not improve solvent cracking resistance, and when it exceeds 50 parts by weight, the mechanical properties of the composition become humiliated. These two polymers (1) and (2) can in the form of their latices by a Mixer, e.g. B. on the roller or in a Banbury mixer, or mixed in a solvent.

The latices can be coagulated in the usual way. These methods make use of the Use of an inorganic metal salt, such as the chlorides and sulphates of sodium, calcium, Magnesium or aluminum or an organic metal salt such as potassium tartrate as a coagulant with or without simultaneous use of an inorganic acid such as sulfuric acid, hydrochloric acid, Phosphoric acid or silica, or an organic acid such as acrylic acid, citric acid or Tartaric acid. The amount of the metal salt is 1 to 5% based on the rubber solids content in the latex, and the amount of acid is 0 to 6% by weight on the same basis. The solvent cracking resistance the composition usable in the present invention can be further improved by using a polymer an α, β-ethylenically unsaturated carboxylic acid, such as an acrylic acid polymer, a methacrylic acid polymer or an acrylic acid-methacrylic acid copolymer or its ammonium salt as Coagulant and the metal salt mentioned for the coagulation of the latex of the copolymer (1) or the mixture of the latices of the copolymers (1) and (2). This coagulant will particularly preferred, as there is corrosion of the metal machine parts in the dehydration and Inhibits drying process. If you wish, you can this coagulant can be used together with the above known acid. In this case, a small amount such as up to 2% by weight may suffice and practical no corrosion of the machine parts.

The polymer composition is in a conventional manner using sulfur or a Vulcanized peroxides. In addition to the vulcanizing agent, common additives such as VerTabelle II

094 2

Tonics, extenders, plasticizers, antioxidants or pigments, can also be added.

The polymer composition which can be used according to the invention can, like the customary butadiene-acrylonitrile copolymer alone or in a mixture with natural or synthetic rubber for Production of gasoline hoses, packing material, oil seals, Sealing rings, belts, rollers used for looms, pressure rollers or diaphragms will.

The following examples describe the invention without restricting it. Refer to each example parts and percentages are based on weight.

example 1

The polymerization was carried out according to the recipe given in Table I at 35 ^° C. in an autoclave with a capacity of approx. 12 liters until the conversion of the monomer reached 85%. After completion of the reaction, a commercially available antioxidant was added to the latex, and the latex was coagulated with an aqueous solution of aluminum sulfate, followed by washing with water and drying in a vacuum dryer to form a liquid copolymer. The total acrylonitrile content (%) of the resulting copolymer was determined by the method according to Kj βία ah 1 *. The total carboxyl group content (moles of COOH per 100 parts of rubber) was determined by titration. The number average molecular weight was measured with an ebulliometer. The properties of the polymer are shown in Table II.

Table I parts

Monomers (see Table II) 100

Water 250

Sodium dibutylnaphthalene

sulfonate 3.0

Sodium dodecylbenzenesulfonate 1.0

Sodium sulfate 0.2

H ₂ SO ₄ 0.1

Potassium persulfate 0.3

tert-dodecyl mercaptan (variable

Amounts,
see table II)

rehearse Polymerization conditions Butadiene Monomers (parts) tert-dodecyl Properties of the polymer Carboxyl Numerical mean Quantities of the fed 55 Methacrylic acid mercaptan amount
(Parts) Acrylonitrile group salary of the molecular
weight Acrylonitrile 54.5 10.0 salary
(%) 1880 A. 45 53 0.5 10.0 42.5 0.005 1910 B. 45 48.5 2.0 10.0 42.4 0.022 1870 C. 45 45 6.5 10.0 43.1 0.075 2020 D. 45 63 10.0 10.0 43.5 0.110 1980 E. 45 50 2.0 9.0 43.2 0.024 1930 F. 35 48 - 12.0 33.8 - 1890 G 50 53 2.0 12.0 45.8 0.021 1910 H 50 53 2.0 17.0 45.2 0.023 1150 I. 45 53 2.0 3.5 42.5 0.023 6010 J 45 53 **) 2.0 *) 10.0 42.8 0.025 1980 K 45 2.0 10.0 43.3 0.022 2020 L. 45 43.2

·) Acrylic acid was used instead of methacrylic acid. ··) Isoprene was used instead of butadiene.

100 parts of a mixture of the resulting liquid copolymer and a commercially available butadiene-acrylonitrile copolymer, 5 parts of zinc oxide, 1 part of stearic acid, 0.3 part of sulfur, 65 parts of quickly injectable furnace black, 15 parts of dioctyl phthalate and 20 parts of tetramethylthiuram monosulfide were applied to a roller mixed, and the mixture was ^{vulcanized at 150 °} C. for 30 minutes. The properties and solvent cracking resistance of the vulcanized products obtained are shown in Tables III to V.

The measurement of the solvent cracking resistance was carried out as follows:

On a rectangular test specimen 10 mm wide

and 2 mm thickness, indicator lines were drawn in at 10 mm intervals. In the middle between two adjacent indicator lines, a 2 mm thick damage was made parallel to the indicator lines up to their back with a razor blade. The test piece was fixed in a jig which could be expanded to a tension ratio of 100%. At this point in time, the distance between the clamps ίο was a constant 30 mm. The test piece was placed in a tense state in a test solvent (a mixture of isooctane and toluene in a volume ratio of 40:60) at 30 ^° C., and the time until the sample was broken was measured.

Table III

Attempt no.

2 3

(Comparison) (comparison)

Butadiene-acrylonitrile copolymer (parts)
Liquid copolymer (sample no.)
f parts)

Properties of the vulcanized products
Tensile strength (kg / cm ² )
Strain (%)
300% module (kg / cm ³ )
Hardness (JIS)

Resistance to solvent cracking
(Break time)

100 80 80 80 80 80 - A. B. C. D. E. - 20th 20th 20th 20th 20th 171 139 142 146 158 167 480 530 470 460 480 420 137 106 108 110 114 124 67 63 65 64 68 69 0'43 " 1'54 " 4'41 " 12Ό4 " 10'45 " 9'23 "

As can be seen from Table III, the fact that the group is, can only be improved slightly Butadiene-acrylonitrile copolymer alone a low 4 ° (see experiment no. 2). In contrast, the Resistance to solvent cracking. The polymer compositions of the present Er solvent crack resistance of a mixture finding (experiments No. 3 to 6) an extraordinarily of the butadiene-acrylonitrile copolymer and a good solvent crack resistance. liquid copolymer that is free of carboxyl

Table IV

Experiment No. 7 8

9 10

(Comparison)

12 13

(Comparison)

Butadiene-acrylonitrile copolymer 90 60 - - 80 80 80

(Parts)

Butadiene-acrylonitrile copolymer - - 100 80 - - -

(Parts)

Liquid copolymer (sample no.) C C - C F G H

(Parts) 10 40 - 20 20 20 20

Properties of the vulcanization product

Tensile strength (kg / cm ² ) 149 126 166 143 152 142 139

Elongation (%) 480 520 510 490 460 510 470

300% module (kg / cm ² ) 120 94 141 118 109 108 118

Hardness (JIS) 68 63 69 67 65 63 66

Resistance to solvent cracking 9Ί3 "17'29" 0'58 "10'47" 8'51 "1'39" 12Ό7 '

As can be seen from the results in Table IV, polymer compositions can with Excellent solvent cracking resistance can be obtained when the mixing proportions the liquid copolymers

were changed (experiments no. 7, 8 and 4) and if the acrylonitrile content of the butadiene-acrylonitrile copolymer or the liquid copolymer containing carboxyl groups has been changed (experiment no. 10, 11 and 13).

Table V

Attempt no.
14 15

17th

Butadiene-acrylonitrile copolymer (parts) Liquid copolymer, sample no.
(Parts)

Properties of the vulcanized product

Tensile strength (kg / cm ² )

Strain (%)

300% module (kg / cm ² )

Hardness (JIS)

Resistance to solvent cracks (break time) 27'00 '

85 70 80 80 I. J K L. 15th 30th 20th 20th 140 150 137 172 560 480 390 520 88 111 96 126 60 67 63 69 27'00 " 16'20 " 19'23 " 5'43

As can be seen from Table V, polymer compositions with excellent Resistance to solvent cracking can be obtained if the molecular weight of the liquid Copolymer was changed (experiments no. 14 and 15) when acrylic acid instead of methacrylic acid (Trial No. 16) and when isoprene was used instead of butadiene (Trial No. 17).

Example 2

The polymerization was carried out at 5 ° C. using the polymerization recipe given in Table VI. When the conversion reached at least 85%, the polymerization was stopped. A commercially available antioxidant was added and a latex was obtained with an acrylonitrile content of 42.5% and a Mooney viscosity (100 ° C / ML _{1 + 4} ) of 65.0.

Table VI

Parts

Acrylonitrile 45

Butadiene 55

Water 230

Sodium Acylnaphthalene Sulphonate 1.5

Sodium alkylbenzenesulfonate 2.0

tertiary sodium phosphate 0.2

FeSO ₄ 0.01

tert-dodecyl mercaptan ... 0.50

Sodium ethylenediamine tetraacetate ... 0.03

Sodium Aldehyde Sulphoxylate 0.06

p-menthane hydroperoxide 0.05

To a mixture of 80 parts by weight of this latex and 20 parts by weight (in each case as rubber solids content) of latex C, obtained according to Example 1, a 5% aqueous solution of acrylic acid polymer with a degree of polymerization of about 2000 was added and then a 0.3% aqueous solution a metal salt (s. Table VIII) mixed solution with the latex to coagulate the latex at 30 to 4O ⁰ C was coagulated. The friable product obtained was washed with water and dried in vacuo at 5O ⁰ C for 24 hours. The rubber was then mixed on a roller in accordance with the recipe of Table VII. The mixture was ^{vulcanized at 160 °} C. for 10 minutes.

40

55

Table VII

Parts by weight

Rubber 100

Zinc oxide 5

Stearic acid 1.0

Sulfur 0.3

Medium abrasion-resistant furnace black 80

Dioctyl phthalate 20

Tetramethylthiuram disulfide 2.0

N-Cyclohexylbenzthiazylsulferiamide. 0.2

N-phenyl-N-isopropyl-p-phenylenediamine 1.0

The solvent cracking resistance of the vulcanized product obtained and its physical properties are shown in Table VTII. The amount of coagulant in the tables below is based on 100 parts by weight of rubber solids in the latex.
As can be seen from Table Vm, the simultaneous use of the metal salt and the acrylic acid polymer brings about a further improvement in the solvent resistance of the vulcanized rubber composition.

709 607/244

Table VIII

Coagulants

Attempt no.

(Comparison)

Metal salt (2.7 parts)

Amount of acrylic acid polymer

Aluminum sulfate 0

Properties of the vulcanization product

Tensile strength 124 (kg / cm ² )

Elongation (%) 410

300% modulus (kg / cm ² ) 103

Hardness (JIS) 66-59

Resistance to

Solvent cracks

At 25 ⁰ C 3'09 "

At 40 ⁰ C 0'55 "

aluminum

sulfate

0.9

117

420

94

65-57

7'23 "2Ί5" aluminum sulfate

1.8

118

440

94

68-57

6Ό3 "
2Ό8 "

Calcium chloride

1.8

125

410
105
67-57

6Ί6 "
2Ί6 "

Calcium chloride
2.7

130

440
103
70-55

6'46 "
1'43 "

Example 3

The procedure of Example 2 was repeated except that the coagulant used was changed as shown in Table IX. The solvent cracking resistance was measured ^{at 20 and 40 ° C.} The results obtained are shown in Table IX.

Table IX

Attempt no.

1 (comparison)

Coagulant (parts)

Calcium chloride 2.7

Sulfuric acid 0.9

Acrylic acid polymer Properties of the vulcanized products As can be seen from Table IX, the results use of acrylic acid polymer as a coagulant along with the metal salt and the fcaiire, an increased improvement in solvent resistance the vulcanized rubber composition.

Tensile Strength (kg / cm ² ) 119

Elongation (%) 500

300% modulus (kg / cm ² ) 93

Hardness (JIS) 68-61

Resistance to solution 14'39 "medium cracks

at 20 ⁰ C 14'39 "

at 40 ⁰ C 2'24 "

2.7 0.9 0.9

114 560 80

63-57 25'54 "

25'54 "6'35"

Example 4

The mixed latex made according to Example 2

r ^ir t ^e - ^U ?, ^{ter application of} a coagulant

the IaDeIIeX coagulates and washed with water.

The resulting lump of rubber with about 40%

water content was between steel plates (SAE-1020)

TaSZ ⁰ L , ^{m a Gur-} Oien for 20 hours at IW) C. The lump and steel plates .c JK? ^ excepted, and the corrosion on the surfaces of the steel plates was assessed with the naked eye. The results are shown in Table X.

Table X shows that the use of acrylic acid polymer as a component of the 5 »Coagulant a remarkable improvement those called by the rubber pumpkin Corrosion leads to steel

Table X Coagulants

Metal salt (2.7 files)
Acid (2.7 parts)

Corrosion of the steel plates

Attempt no.

(Comparison)

Aluminum sulfate

sulfuric acid

large

2 (comparison) aluminum sulfate
phosphoric acid
considerably large

(Comparison)
Aluminum sulfate
hydrochloric acid
large

Al
sulfate

Acrylic acid polynrerisÄ

11 12

Example 5 A mixture of 80 parts by weight (as rubber

It was according to the solids content specified in Table XI) of this latex with 20 parts by weight

Polymerization recipe polymerized at 35 ° C. As ^of latex C of Example 1 was used

the conversion reached at least 85%, ^ειη "coagulant of Table XII was coagulated,

the reaction stopped. A commercially available ⁵ % strength aqueous solution of the ammonium salt

Antioxidant was then added, an acrylic acid polymer (degree of polymerization approx.

a latex with an acrylonitrile content of 42.3% and ²⁵ ° 0) was previously treated with the above

a Mooney viscosity (100 ⁰ CZML _{1 (1} ) of 57.5 mixed latex mixed, | and a 0.3% aqueous

was obtained. Solution of the metal salt was added to the latex at the

lo point of the coagulation treatment added, with

Table XI the latex was coagulated ^{at 30 to 40 ° C.} The

Parts of coagulum was washed with water and im

Acrylonitrile 45 vacuum for 24 hours at 5O ⁰ C dried. After that

Butadiene 55 was the rubber on a roller in

Water 250 15 mood with that given in Table VII

Sodium alkylnaphthalenesulfonate 2.5 formulation mixed and then at 160 ⁰ C for 10 minutes

Sodium alkylbenzenesulfonate 1.0 pressure vulcanized. The properties and resistance of sodium sulfate 0.2 resistance to solvent cracking of the

Potassium persulfate 0.3 tenen vulcanization products are listed in Table XII

tert-Dodecyl mercaptan 0.52 20 can be found.

Table XII

Coagulants

Attempt no.

(Comparison)

Metal salt (4 parts) Aluminum sulfate Aluminum sulfate Calcium chloride Amount of the ammonium salt of the 0 1.8 1.8 Acrylic acid polymer (parts) Properties of the vulcanized product Tensile strength (kg / cm ^s ) 125 134 130 Strain (%) 430 500 470 300% module (kg / cm ⁸ ) 103 108 106 Hardness (JIS) 66-59 68-57 67-57 Resistance to solvent cracking At 25 ° C 3'20 " 12Ί0 " 14Ί3 " At 40 ⁰ C 0'50 " 2'35 " 2 '55 "

It can be seen from Table XII that the use of the ammonium salt of an acrylic acid polymer as a component of the coagulant results in a vulcanized rubber product which has superior solvent cracking resistance; having.

Table XIII Example 6

Example S was repeated with the difference that the coagulant of Table XIII was used. The properties of the emerging vulcanized product were evaluated. The solvent cracking resistance was measured at 17 ° C and 40 ° C measured. The results are the See table Xffl.

As can be seen from the table ΧΤΠ, the Use of the ammonite salt of an acrylic acid polymer together with the metal salt and one Acid an increased improvement in solvent

Experiment no. 1 2

(Comparison)

Coagulant (parts) Calcium chloride 4 2.7 Sulfuric acid 0.9 0.9

Ammonium salt of acrylic 0.9 acid polymer

Properties of the vulcanized product Tensile strength (kg / cm ¹ ) 113 109

Elongation (%) 490 560

3C0% Modal (kg / cm ² ) 98 94

Hardness (JIS) 68-61 63-57

Resistance to solution ^ " ^N WlS " 21'30 ^ central cracks - 3 2Ί8 " 4'40 " At 17-C At 40 ^e C

13 14

Example 7
Example 4 was repeated using the mixed latex of Example 5 and the coagulation

means of Table XIV. Attempt no.
1
(Comparison) 2
(Comparison) 3 Table XIV Aluminum sulfate Aluminum sulfate Aluminum sulfate Coagulants sulfuric acid hydrochloric acid Ammonium salt of
Acrylic acid polymer Metal salt (4 parts) latte big large small Acid or ammonium salts
(2.7 parts) Extent of corrosion of the steel plate

From Table XIV it can be seen that the means of a remarkable improvement in corrosion an ammonium salt of the acrylic acid sion level of the steel plate by the rubber Polymer as a component of the coagulation ao causes.

Comparative experiments
1. Manufacture of the polymers

The polymerization reaction was carried out in a bottle, the reaction was stopped. After that , 2.5 ge

interpolymerization apparatus according to the polymer weight percent, based on the oil solids

sation recipe carried out in Table 1. After containing diphenylamine, added. The property

a predetermined conversion has been achieved, th of the samples A to E thus obtained are in

Hydroxylamine sulfate was added, which Table 2 summarizes.

Table 1

rehearse B. C. D. E. A. 55 55 85 Butadiene - - 65 Isoprene 65 35 35 15th 35 Acrylonitrile 33 10 10 Methacrylic acid 2 3.0 ' 3.0 2.0 2.0 Sodium dibutylnaphthalene sulfonate 3.0 1.0 1.0 1.0 1.0 Sodium dodecyl benzosulfonate 1.0 0.2 0.2 0.2 0.2 Sodium sulfate 0.2 0.1 0.1 sulfuric acid 0.1 0.3 0.3 Potassium persulfate 0.3 - - 0.08 0.08 Sodium formaldehyde sulfoxylate - - - 0.02 0.02 FeSO, · 7H ₈ O - - - 0.05 0.05 Sodium ethylenediamine tetraacetate - - - 0.08 0.08 para-menthane hydroperoxide - 10.0 0.38 0.26 0.38 tert-dodecyl mercaptan 10.0 250 250 200 200 water 250 30 ⁰ C 30 ⁰ C 5 ° C 5 ° C Polymerization temperature 30 ⁰ C Table 2 sample B. C. E. A.

Final conversion (%) Combined Acrylnftrilmenge (%) of methacrylic acid carboxyl equivalent number average molecular weight Mooney viscosity (ML _{1 +} at 100 ⁰ Q

93.0 92.3 87.5 58.2 87.4 32.5 34.3 34.2 21.3 34.5 0.023 0.110 0.105 _ _ 1890 1930 _{| | | : i} ,

55.0

73 ^ 0

Attempt 1

A butadiene-acrylonitrile rubber latex (combined amount of acrylonitrile 33.5%, ML _{1 + 4} at 100 ⁰ C = 78.0) and a latex of the sample A (Carboxyl liquid acrylonitrile Isoprencopolymeres) were mixed together in such a manner to a solids content -Weight ratio of 75:25 to give (composition according to the invention).

Furthermore, the above-mentioned latex or a latex made of butadiene-acrylonitrile rubber (combined amount of acrylonitrile 34.0%, MLj ₊₄ at 100 ⁰ C == 45.0) was mixed with a latex of sample E (rubber-like acrylonitrile-isoprene copolymer) mixed together in such a way as to give a solids content / weight ratio of 75:25 (composition according to DT-OS 20 01 695).

These intermingled latices were made with a CaI-

Table 3

ciumchloridlösung acidified with sulfuric acid, coagulated and dried under reduced pressure at 50 ⁰ C to obtain samples for the evaluation of the rubber mixtures.

100 parts (here and below based on weight) of the rubber mixture thus obtained, 5 parts of zinc oxide, 1 part of stearic acid, 0.3 part of sulfur, 65 parts of quickly injectable furnace black, 15 parts of dioctyl phthalate and 2.0 parts of tetramethylthiunundisulfide were mixed on rollers , and the mixtures were ^{vulcanized at 150 °} C. for 30 minutes. The properties of the vulcanized products obtained are shown in Table 3. Furthermore, in batch 3, the butadiene-acrylonitrile rubber used was that with the low Mooney viscosity, in order to bring the Mooney viscosity of the rubber mixture closer to that of the composition according to the invention.

Approach no. 2
(DT-OS 20 01 695) 3
(DT-OS Rubber compound 1
(according to the invention) 2001695) (Nitrile rubber / sample) Sample E. Sample E. Sample A 72.0 51.0 MLi _{+ 4} at 100 ⁰ C the mixtures 46.0 Properties of the vulcanized products 280 261 Tensile strength (kg / cm ² ) 162 360 400 Strain (%) 490 215 182 300% module (kg / cm ² ) 112 77 75 Hardness (JlS) 67 0'43 " 0'51 " Resistance to solvent cracking (break time) T 30 "

Table 3 shows that the composition according to the invention is due to the Composition of DT-OS 20 01 695 not foreseeable considerably better resistance to solvent cracks having.

Attempt 2

Tests were carried out as indicated under Experiment 1, with the difference that the in

Table 4

Mixtures given in Table 4 were used instead of the mixtures used in Experiment 1. The results are summarized in Table 4.

It can be seen from Table 4 that the composition according to the invention has excellent resistance against solvent cracking, which due to the composition of US Pat. No. 3,063,960 was not to be expected.

Approach no.

1 2

(according to the invention)

Percent by weight of the mixtures

(U.S. PS
30 63 961)

Butadiene-Acrylonitrile Rubber (Sample D) Liquid carboxyl-modified butadiene-acrylonitrile copolymer (Sample B)

Rubber-like carboxyl-modified butadiene-acrylonitrile copolymer (Sample C) polyvinyl chloride

ML _{1 + 4} at 100 ^° C. of the mixtures

Properties of the vulcanized products Tensile strength (kg / cm ⁸ )

Strain (%)

300% module (kg / cm ^a )

Hardness (JIS)

Resistance to solvent cracking (break time)

80 20th

80

20th

- - 40 51.5 68.5 85.0 151 201 229 470 400 360 103 153 175 65 69 83 6'21 " l'30 " 0'55 " in B07 / J44

Claims (1)

the achievement of such an excellent solution patent claim: Medium crack resistance, as achieved according to the invention Use of a polymer composition is. _from It is therefore object of the invention, an oil-resistant (1) 5 to 50 wt .-% of a copolymer, wel- 5 polymer composition to provide which Ches from 50 to 80 wt .-% butadiene or is subject to an extremely small increase in cracks if Isoprene, 20 to 50 wt .-% acrylonitrile and they come in contact with highly aromatic solution-0.1 up to 10% by weight of a 0-ethylenic is not average saturated carboxylic acid and a number. The invention thus relates to the use of a average molecular weight of about 500 io polymer composition to 10,000, and (1) 5 to 50% by weight of a copolymer which (2) 95 to 50% by weight of a butadiene-acrylonitrile from 50 to 80% by weight of butadiene or isoprene, Copolymers 20 to 50% by weight of acrylonitrile and 0.1 to 10% by weight for the production of rubber vulcanizates,% of an α, / 9-ethylenically unsaturated carbon which are used in contact with oil. 15 acid and which is a number average of the Molecular weight from about 500 to 10,000 owns, and When rubber comes into contact with chemicals or (2) 95 to 50% by weight of a butadiene-acrylonitrile Solvents are used, will change copolymers gene of the volume, the strength and the elasticity 20 for the production of rubber vulcanizates, the module on important problems. used in contact with oil. When rubber comes into contact with a solvent When testing the polymer composition in the is brought, it is often brought within a short time in view of the phenomenon of solvent cracking a low elongation, which in air does not occur under the conditions described below Rupture would lead to broken. This phenomenon has been found to have a cracking life the increase in cracking in solvents is exhibited by more than about 5 minutes, which is a large one in the field of plastics as a "solvent crack" improvement. Therefore, the invention can be known. However, few reports of proper polymer composition exist for much study this phenomenon in rubber. number of uses to be used where The occurrence of solvent cracks should of course be 30 Resistance to highly aromatic solvents in the case of rubber materials, which is required in sedatives. Since the invention is to be used with gasoline, reversible compositions are avoided, and therefore rubber collapses have a superior resistance to settling essentially on the basis of butadiene compared to conventional butadiene-acrylonitrile-acrylonitrile copolymers to a large extent - 35 copolymer compositions, can be used under. As a result of the social desire for strict conditions, e.g. B. in gasoline with a high conclusion of lead as a component of gasoline aromatic content will be used,
expects that the content of aromatic constituents will increase (the aromatic content of isoprene, acrylonitrile and an unsaturated carbohydrate now used gasoline is estimated at approx. 50%). 40 bonsäure of low molecular weight (approx. 500 The phenomenon of the solvent cracking would therefore be up to 10,000), which according to the invention become a practical problem even with the application, is prepared by means of a conventional emulsion-known butadiene-acrylonitrile copolymer polymerization formulation. The polymer compositions. In adopting such a situation sation level may be low (about 0 ⁰ C) or was tion the phenomenon of solvent cracks 45 high (30 to ⁰ SO C). Therefore, the polymerization of rubber in a mixed solvent can be studied by initiator a redox catalyst or a radical isooctane and toluene in a ratio of 40:60 catalyst such as potassium persulfate and / or an organics. As a result, it was found to be niche peroxide. The polymerization can be carried out either as a standard butadiene-acrylonitrile copolymer batch or continuously, batch composition which can now be used on a large scale Dicarboxylic acid, e.g., under the conditions described below) acrylic acid, methacrylic acid, maleic acid and itacone of less than one minute and can be used for an acid. The proportion of carboxylic acid which is not sufficiently resistant to polymer-practical use is 0.1 to 10% by weight. is. 55 If the proportion is less than 0.1% by weight, DT-OS 20 01 695 describes a mixture of can the resistance of the polymer together with an isoprene-acrylonitrile copolymer and a composition against solvent cracks not ver-butadiene-acrylonitrile copolymer. These copolymers are improved, and if it exceeds 10% by weight, the risat composition is, however, inferior to the solvent cracking resistance and solvent cracking resistance of the other properties undesirably used according to the invention,
gen. The polymer composition according to the invention The composition described in US Pat. No. 3,063,961 is a mixture of (1) 5 to 50 parts by weight composition is a ternary mixture of one of this low molecular weight polymer and (2) 95 bis Butadiene-acrylonitrile copolymer, a carboxyl 65 50 parts by weight of a conventional butadiene-acrylonitrile. modified butadiene-acrylonitrile copolymer and copolymers with an acrylonitrile content of approx a chlorinated vinyl chloride homo- or copoly- 20 to 50% by weight, where the sum of (1) and (2) merisat. This composition also does not allow 100% by weight. When the amount of copoly-