DE1262588B - Vulcanizable, easily processable molding compounds based on butyl rubber - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08f

German KL: 39 b ^ 22 / 06- $} /

Number: 1262 588

File number: D 33896IV c / 39 b

Filing date: July 29, 1960

Opening day: March 7, 1968

The invention relates to vulcanizable, easily processable molding compositions based on butyl rubber, that of a) 40 to 70 percent by weight of a butyl rubber with a Mooney viscosity above 65 or below 50 and b) 60 to 30 percent by weight of a rubbery one, a Mooney viscosity above 65 or under 40 having olefin copolymer of one or more monoolefins with 2 to 10 carbon atoms and a hydrocarbon with more than one ethylenic double bond and c) usual There are rubber vulcanizing agents and auxiliaries, with b) of the order of magnitude is the same unsaturated as a), but has a viscosity very different from a) and the mixture of a) and b) has a Mooney viscosity of 40 to 60.

"Butyl rubber" is a copolymer of an isoolefin, generally isobutylene, with a small proportion, generally less than 5 ⁰ I ₀ , diolefin, such as. B. butadiene and isoprene understood.

Butyl rubber has the advantage of being cheap and impermeable to air, on the one hand, and vulcanized, on the other however, it is slow and does not have favorable tensile properties if the viscosity does not is high; however, a high viscosity in turn worsens the processability. Olefin copolymer rubber also has this disadvantage.

The aim of the present invention is now to provide vulcanizable and easily processable molding compounds to produce on the basis of butyl rubber, which have strength properties that match those of high-viscosity butyl rubber or olefin mixed polymer rubber come close or equal and which can also be easily vulcanized.

The butyl rubber is mixed with an olefin mixed polymer rubber in relative proportions between about 40 and 70 and 60 to 30 percent by weight, the olefin mixed polymer rubber being approximately the same unsaturated as the butyl rubber. The mixtures of the two rubbers have a Mooney viscosity (ML-8 at 52 ^° C.) of 40 to 60.

A highly viscous butyl rubber (Mooney viscosity over 65, preferably over 70, for example 70 to 85) with a low-viscosity olefin copolymer rubber (Mooney viscosity below 40, preferably below 30, for example 20 to 30) or a highly viscous olefin copolymer rubber (Mooney viscosity below 65, or preferably above 70, for example 70 to 100) with a low-viscosity butyl rubber (Mooney-Vis-

Vulcanizable, easily processable molding compounds based on butyl rubber

Applicant:

Dunlop Rubber Company Limited, London

Representative:

Dr. F. Zumstein, Dr. E. Assmann

and Dr. R. Koenigsberger, patent attorneys,

8000 Munich 2, Bräuhausstr. 4th

Named as inventor:
Stephen Adamek,
Edward Allan Dudley,
Toronto, Ontario (Canada)

viscosity below 50, for example 40 to 50) are mixed. Mixtures that have roughly equal parts of the two Components contain, for example, about 45 to 55 percent by weight butyl rubber and the corresponding Part olefin copolymer rubber are particularly favorable. It is noteworthy that the In terms of their strength properties, molding compositions according to the invention are those of highly viscous Butyl rubber or olefin mixed polymer rubber alone come close to or equal to and above can also be processed much more easily and have improved tack.

The butyl rubber component is preferably a copolymer of isobutylene (95 to 99.5%) with 1,3-butadiene and / or isoprene (5 to 0.5%).

The olefin copolymer rubber is a

Copolymer of one or more monoolefins containing 2 to 10 carbon atoms with a compound that has more than one ethylenic double bond, especially a system of conjugated Contains double bonds (for example butadiene, isoprene or cyclopentadiene), ζ. Β. a unsaturated endocyclic hydrocarbon containing two or more ethylenic double bonds contains. Examples of such hydrocarbons are derivatives of bicyclo- (2,2,1) -heptadiene and bicyclopentadiene (1,4-endomethylene hydrind-2,6-diene); Derivatives of bicyclo- (2,2,2) -octadiene such as, for example Bicyclo- (2,2,2) -octa-2,5-diene and derivatives of bicyclo- (3.2, l) -octadiene, bicyclo- (3.3, l) -nonadiene and

809 517/741

Bicyclo- (3,2,2) -nonadiene. Terpolymers of ethylene, propylene and dicyclopentadiene, for example those with a propylene content of 40 to 50%, which are 2 to 4% unsaturated, are special valuable (the term "mixed polymer" is not intended to refer to a two-component system in the present description be limited).

The exact relationship between the degree of saturation of the butyl rubber and that of the olefin copolymer rubber is not important as far as both degrees of saturation are necessary for effective vulcanization sufficient (e.g. 0.75% or more unsaturated). In general, the two values are for the unsaturation favorably between 0.75 and 4% and are within these limits as »approximately similarly unsaturated «.

The molding compositions according to the invention can be vulcanized with sulfur in a known manner, however, it has been found that a product with improved physical properties is obtained, when the sulfur vulcanization by adding a small amount, for example 0.25 to 2%, of one known peroxide vulcanizing agent, especially dicumyl peroxide, is promoted. This easy vulcanizability of the mixtures is surprising in that it has always been viewed as unfavorable Vulcanize butyl rubber together with other types of rubber without first using it, for example by halogenation to modify.

Be i s ρ i e 1 1

In this example, a molding composition according to the invention was compared with two control samples, from which one from the one used in the molding compound

Butyl rubber and the other from -dem-also in the molding compound used olefin copolymer rubber duration. A 1.52% unsaturated polyisobutylene-isoprene rubber was used as the butyl rubber with a Mooney viscosity of 74, an olefin copolymer rubber which is 3.0% unsaturated Terpolymer of ethylene, propylene and dicyclopentadiene with a content of 42% propylene and a Mooney viscosity of 22 was used. The following three mixtures were produced:

- - Butyl rubber -..-..-.-.-.- ;.

Olefin copolymer.
Highly abrasion-resistant furnace soot

Zinc oxide

Stearic acid

-100

50

5 2

5fr 50 50

. 5 2

100 parts each of A, B and C were made with the following Mixed vulcanizing agents:

Tetramethylthiuram disulfide
Tellurium diethyl dithiocarbamate

sulfur

Dicumyl peroxide

0.5

The rubber samples were then vulcanized ^{at 160 ° C. for 30 minutes.}

The physical properties of the blend and the two control samples are as follows Given in the table.

Butyl rubber A.

mixture

Vulcanization regulation
THE

Olefin copolymer C

300% modulus, kg / cm ²

Tensile strength, kg / cm ²

Strain, %

Elasticity,% (Tripsometer)
Hardness, degree

119 158 410

70 to 65

440

70 to

. 116 121 135 156 340 400 - 46 76 to 71 76 to 70

66 230

73 to 70

91

98

320

48

77 to 70

The table above shows that when low-viscosity olefin copolymer rubber is concentrated the strength properties of butyl rubber only marginally affect the mixtures are influenced, but their elasticity increases significantly. In addition, the mixes Process and vulcanize considerably better than butyl rubber.

Example 2

In this example, a mixture based on a highly viscous olefin copolymer rubber was used compared to two control samples, one of which was olefin copolymer rubber itself and the other was the butyl rubber used in the mixture. The former consisted of one to 2% unsaturated copolymer of ethylene, propylene and dicyclopentadiene with a content of 37% propylene and a Mooney viscosity of 75. The butyl rubber was 2.09% unsaturated relatively low molecular weight copolymer made from isobutylene and isoprene with a Mooney viscosity from 45.

The following three mixtures were made:

Olefin copolymer

Butyl rubber

Highly abrasion-resistant furnace soot

Zinc oxide

Stearic acid

Mineral extending oil

100

50 5 2

15th

50

50

50

100

100 parts each of A, B and C were mixed with vulcanizing agents D and E from Example 1 and vulcanized at 160 ^° C. for 30 minutes.

The physical properties of the blend and the two control samples are as follows Table specified:

Olefin copolymer A

mixture

Vulcanization regulation
THE

Butyl rubber
C.

300% modulus, kg / cm ² tensile strength, kg / cm ² ..

Elongation,% ■

Hardness, degree

80.6 175 550 73 to

98

211

525

69 to 114

169

430

70 to 65

112

182

440

73 to 70

113

149

410

73 to 70

124

135

320

72 to 68

From the table above it can be seen that the addition of low-viscosity butyl rubber to the mixture has only a relatively minor influence on the strength properties of the olefin copolymer rubber, however, the mixture is lighter than the olefin copolymer rubber alone, which is not can be satisfactorily processed without at least 15 parts of oil (per 100 parts of rubber) and lets process.

Example 3

In this example, a mixture was assumed to be about 1% unsaturated and a

The basis of a highly viscous olefin copolymer had a Mooney viscosity of 97. As butyl rubber

rubber with the two components of the Mi- was a 2.1% unsaturated isobutylene-isoprene

compared for itself alone. The olefin mixed copolymer with a Mooney viscosity of 45

polymer resembled that of Example 2, used with the Aus.

The following three mixtures were made:

Olefin copolymer

Butyl rubber

Highly abrasion-resistant furnace soot

Zinc oxide

Stearic acid

Tetramethylthiuram disulfide tellurium diethyldithiocarbamate

A. B. 100 50 - 50 50 50 5 5 2 2 1 1 0.5 0.5

100
50
5
2
1
0.5

These three blends gave 40 high Mooney viscosity increases after 30 minutes. Vulcanization of the same length of time at 152 ° C with rubber samples at the same time reduced the processability of the olefin mixture as follows Properties: Polymer by mixing with the butyl rubber

can be significantly improved.

300% modulus, kg / cm ² tensile strength, kg / cm ² ..

Strain, %

Hardness, degree

Tear strength in the cold at 21 ^° C., kg / cm ²

Tear strength in the heat at 100 ^° C., kg / cm ²

Rebound resilience at 21 ° C

Olefin mixture

81.2 123 450

71

60

16 62.5

mixture

108

168

460

72

61

32 57.5

Butyl rubber

133

143

305

73

45

25 35.0

55

In this example the tensile strength of the mixture is better than that of each component, the tear strength is improved and the elasticity of the butyl rubber is improved by the incorporation of the olefin copolymer

Claims (1)

Claim: Vulcanizable, easily processable molding compounds based on butyl rubber, thereby characterized in that it consists of a) 40 to 70 percent by weight of a butyl rubber with a Mooney viscosity above 65 or below 50 and b) 60 to 30 percent by weight of a rubbery, an olefin copolymer having a Mooney viscosity above 65 or below 40 one or more monoolefins with 2 to 10 carbon atoms and a hydrocarbon with more than one ethylenic double bond and c) customary rubber vulcanizing agents and - Auxiliaries exist, where b) is of the same order of magnitude as a), but one of a) has very different viscosities and the mixture of a) and b) has a Mooney viscosity from 40 to 60 owns. 809 517/741 2.68 © Bundesdruckerei Berlin