JPS60258239A - Olefin rubber composition - Google Patents

Abstract

PURPOSE:A composition that is composed of a specific ethylene-alpha-olefin copolymer rubber and (halogenated) butyl rubber, thus showing both improved processability and mechanical strength. CONSTITUTION:The objective composition is obtained by mixing (A) an ethylene- alpha-olefin-diolefin copolymer rubber with contains an alpha-olefin of 3-12 carbon atoms at a weight ratio ethylene/alpha-olefin of (80-40)/(20-60), diolefin units bonded of 2-40 in iodine value, less than 20wt% of insoluble fraction in cyclohexane at 30 deg.C, and has, as a green rubber, maximum tensile stress (sigmamax) of 20-150kg f/cm<2> and tensile stress at 100 deg.C elongation (sigma100) of less than 20kgf/cm<2> where sigmamax/sigma100>0.18C+10.5 (C is content of alpha-olefin in wt%), more than 6% of the heat of melting of the crystals melting at 50-100 deg.C based on the total heat of melting of the composition with (B) (halogenated) butyl rubber at a weight ratio of (5-95)/(95-5).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ethylene film with improved processability and mechanical strength.
The present invention relates to an olefin rubber composition comprising α-olefin-diolefin copolymer rubber and butyl rubber and/or halogenated butyl rubber.

Conventional technology Ethylene-α-olefin-diolefin copolymer rubber has excellent heat resistance, weather resistance, ozone resistance, low-temperature properties, electrical insulation properties, and chemical resistance, and is widely used in automobile parts, building material parts, and electrical Used for parts, hoses, industrial supplies, etc.

On the other hand, butyl rubber and/or halogenated butyl rubber have low gas permeability and vibration properties.

It has excellent flexibility and adhesive properties, and is used in tubes, tires, tarpaulins, anti-vibration rubber, sponges, banking products, and other industrial products.

Ethylene-α-olefin-diolefin copolymer rubber and butyl rubber and/or halogenated butyl rubber have good blend compatibility and are used as a blend in such a way that they compensate for each other's shortcomings. For example, Canadian Patent No. 826°933 discloses that tubes for automobile tires are made of a blend of butyl rubber and ethylene-propylene-multi-olefin copolymer to suppress curing 2 heat generation in cold weather. There is. Also, JP-A-56-4
Publication No. 7441 discloses an electrically insulating rubber with improved mechanical strength and adhesiveness. Other Butyl Rubber and Synthetic Rubber Processing Techniques Volume 1, First Edition September 30, 1980, Published by Taiseisha, Author: Hayao Nagano, Pages 58 to 68, heat resistance of waterproof sheets and anti-vibration rubber.

Blends of butyl rubber and ethylene-propylene-diolefin copolymer rubber (EPDM) are described for improved vibration damping properties.

As described above, blends of ethylene-α-olefin-diolefin copolymer rubber and butyl rubber and/or halogenated butyl rubber are currently being put into practical use in many fields, taking advantage of the characteristics of each, but there are still many problems. is left behind.

For example, when manufacturing tubes for automobiles, rubber is required to be soft during processing, has high splice strength, and does not crease or crack like unvulcanized compounded rubber. . 92 months, 9 months
7゜1 1"Rubber with good absorbency, low gas permeability, and excellent heat resistance is desired.

In addition, for waterproof sheets, it is desired that the energy required during rubber kneading is low and that the mechanical strength of the molded rubber is high, and for anti-vibration rubber, rubber with high vibration-proof properties and low fatigue properties is desired. In other words, these problems require a rubber that is soft, has excellent processability, and has good mechanical strength. However, the conventionally used blends of ethylene-α-olefin-diolefin copolymer rubber and butyl rubber and/or halogenated butyl rubber are still not sufficient to meet these demands.

Problems to be Solved by the Invention As a result of intensive studies aimed at solving the problems of the prior art, the present inventors have found that a specific ethylene-α-olefin-diolefin copolymer rubber is combined with butyl rubber and/or
Or, by blending it with halogenated butyl rubber, they found an olefin rubber composition that has excellent processability and mechanical strength, leading to the present invention.

A means for solving the problem, that is, the present invention, comprises an ethylene-α-olefin-diolefin copolymer rubber that satisfies the following conditions (a) to (e);
An olefin rubber composition comprising butyl rubber and/or halogenated butyl rubber, characterized in that the weight ratio of the copolymer rubber to butyl rubber and/or halogenated butyl rubber is 5-95/95-5.

(a) α-olefin has 3 to 12 carbon atoms, ethylene/
α-olefin weight ratio is 80-40/20-60,
The bonding amount of diolefin units is 2 to 40° in terms of iodine value (b) The insoluble amount when the copolymer rubber is dissolved in cyclohexane at 30°C is 20% by weight or less.

(c) The maximum tensile stress (δmax) of raw rubber at 25°C of the copolymer rubber is 20 to 150 kgf/Cnt.

and tensile stress at 100% elongation (σ100) is 20kgf/cj or less.

(d) σmax and σ1° of copolymer rubber. ratio (σmax
/ 6 too) as A, and the A value is greater than the B value given by the following formula.

B--0,18C+10.5 However, C is the α-olefin content (wt%) (e) The heat of fusion of a crystal with a melting point of 50 to 100 °C determined by a differential scanning calorimeter is the total heat of fusion. 6% or more.

In the ethylene-α-olefin-diolefin copolymer rubber of the present invention (hereinafter sometimes referred to as “copolymer rubber”), the α-olefin used as the copolymerization monomer is an α-olefin having 3 to 12 carbon atoms. , Specific examples include propylene, butene-1,4-methylpentene-1,
Hexene-1, octene-1, etc. Preferred is propylene. These α-olefins may contain at least one or two
More than one species can also be used in combination.

Moreover, as the diolefin, at least one type of non-conjugated diolefin is copolymerized. Examples of non-conjugated diolefins include the following compounds.

dicyclopentadiene, tricyclopentadiene, 5-
Methyl-2,5-norbornadiene, 5-methylene-2
- norbornene, 5-ethylidene-2-norbornene,
5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene, 5-(1-butenyl)-
2-norbornene, cyclooctadiene, vinylcyclohexene, 1,5.9-cyclododecatriene, 6-methyl-4,7,8,9-tetrahydroindene, 2.2
'-dicyclopentenyl, trans-1,2-divinylcyclobutane, 1,4-hexadiene, 2-methyl-1
, 4-hexadiene, 1,6-octadiene, 1.7-
Octadiene, 1,8-nonadiene, 1,9-decadiene, 3,6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene, 1,4,7-octatriene, 5-methyl-1,
8-Nonagene.

Among these non-conjugated diolefins, 5-ethylidene-
2-norbornene (ENB) and/or dicyclopentadiene (DCP) are preferred.

The copolymer rubber blended with butyl rubber and/or halogenated butyl rubber (hereinafter sometimes referred to as "butyl rubber") in the present invention must satisfy the conditions (a) to (e) above.

Even if a composition with butyl rubber is obtained using a copolymer rubber that lacks these conditions, only unsatisfactory performance in processability or mechanical strength will be obtained. The copolymer rubber used in the present invention has ethylene chains controlled within an appropriate range and has only a few weak crystals under normal conditions, but it can be strengthened by applying stress such as tension. It is a copolymer rubber that produces crystals, so-called stretched crystals.

(a) The copolymer rubber used in the present invention is as described above (α
-The number of carbon atoms in the olefin is 3 to 12. In addition, the ethylene content (ethylene/α-olefin) in the copolymer rubber is
If the weight ratio exceeds 80% by weight, fluidity deteriorates and wasteful energy is required during kneading, and processing problems such as worsening of biting into the rolls occur.
On the other hand, if less than 40% by weight of copolymer rubber is used, the mechanical strength of the rubber composition will be insufficient.

Further, the amount of diolefin units bonded in the copolymer rubber is in the range of 2 to 40, preferably 5 to 30 in terms of iodine value. If the iodine number exceeds 40, the heat resistance and weather resistance of the olefin rubber composition will deteriorate, while if it is less than 2, sulfur vulcanization will become difficult.

(b) Next, the amount of the copolymer rubber insoluble in cyclohexane at 30°C is 20% by weight or less, preferably 15% by weight or less.

The cyclohexane-insoluble copper content is mainly composed of hard crystal components based on long chain bonds of ethylene, and if this amount exceeds 20% by weight, the ethylene content (ethylene/α-olefin) will decrease to 80% by weight due to deterioration of fluidity. The same processability problems arise when the weight percentage is exceeded.

(c) Next, the maximum tensile stress σ of the copolymer rubber at 25°C,
□ (kgf/cJ) is 20 to 150 kgf/cd, and the tensile stress σtoo at 100% elongation
(kg f / c+d) is 20 kgf/afl or less, preferably 15 kgf/eta or less.

The maximum tensile stress 'mmx (kg f / cJ) is 2
If it is 0 kgf/cJ without grooves, it will not be possible to achieve the desired mechanical strength, while if it exceeds 15 Qkgf/c++1, wasteful energy consumption will be required during kneading, and it will worsen the bite into the rolls. This results in processing problems such as:

Tensile stress at 100% elongation σ+oo (kgf/ci)
generally corresponds to the elastic modulus of the copolymer rubber, and becomes larger due to an increase in cyclohexane-insoluble bone in the copolymer rubber or an increase in the ethylene content (ethylene/α-olefin).

Therefore, the tensile stress at 100% elongation is σ1°.

When (kgf/ctA) exceeds 20 kgf/cJ, the copolymer rubber becomes resinous, causing problems such as poor dispersion of the filler during kneading and an increase in the warming time of one composition left over from the raw rubber.

(d) In the present invention, in order to achieve both processability and physical properties, it is necessary to use a copolymer rubber that has low stress under low elongation and high stress under high elongation. This means that it is necessary to use a copolymer rubber that has high stretch crystallinity.

As an index for this, the maximum tensile stress of copolymer rubber σ□8 and 1
Tensile stress σ at 00% elongation. . The ratio (σmix /
σ,. . ) The larger A is, the better, but generally this A value is determined by the ethylene content (ethylene/α-olefin) of the copolymer rubber.
Therefore, the A value of the copolymer rubber used in the present invention needs to be larger than the B value obtained by the following formula.

B=0.18XC+10.5 where C is the content (% by weight) of α-olefin in the copolymer rubber.

If the A value is below the B value: Stretching of copolymerization 1 1. ,.

If the crystallinity is insufficient, either the processability during manufacturing or the mechanical strength of the product will be insufficient.

For example, even if σ and X of the copolymer rubber are large, if σ100 is large, this condition cannot be satisfied. In this case, the processability during kneading or molding becomes significantly worse.

On the other hand, σ1°. Even if σ and □ are small, this condition cannot be satisfied. In this case, the mechanical strength of the product, especially sufficient tear strength, cannot be obtained.

(e) The copolymer rubber used in the present invention has good processability.

In order to achieve both mechanical strength, it is necessary to have a specific molecular structure, which can be measured by differential scanning calorimetry (DSC) analysis.

The measurement and analysis method using DSC will be described later, but as shown in Figure 1 (DSC
It is necessary that the heat of fusion of the crystal component having a melting point of 50 to 100'C, which is shown by the shaded area in the curve C), is 6% or more of the total heat of fusion.

That is, if a large amount of crystalline components with melting points exceeding 100° C. are present, problems arise in processability.

On the other hand, if the amount of crystal components below 50°C increases, sufficient stretching crystallinity cannot be developed, causing problems mainly in terms of mechanical strength.

Although the essential causes of these phenomena have not been fully elucidated, A. Peterlin et al.
r Sci., A-2, 6, 587 (1968)), the ethylene chain length of the crystal component with a melting point between 50 and 100°C is estimated to be 10 to 20.
It is presumed that this moderate ethylene chain length component acts to promote the crystallization of the amorphous component by stretching.

Regarding the Mooney viscosity of the copolymer rubber used in the present invention, the preferred range naturally changes depending on the formulation, and is not particularly limited as long as the conditions (a) to (e) above are satisfied. But M L +44, +0
30-35o at 0'C, preferably 50-300o. Also, those with high Mooney viscosity may be used as oil-extended rubbers.

In addition, the copolymer rubber satisfying the conditions (a) to (e) above is
It is produced using a catalyst consisting of a combination of an organometallic compound of groups 1 to 1 of the periodic table and a transition metal compound selected from groups 1 to 2 and group 2 of the periodic table.

As the organic metal compound, an organic lithium compound, an organic sodium compound, an organic potassium compound, an organic aluminum compound, etc. are used.

Preferred is an organic aluminum compound.

More preferably, a halogenated organoaluminum compound represented by the following formula is used.

R3-ff1AAX11 Here, R represents an alkyl residue having 1 to 8 carbon atoms. m is in the range of 1.15 to 1.25.

X represents a halogen, preferably a chlorine atom. This aluminum compound is obtained by mixing two or more types of organic aluminum compounds.

Specific combinations include triethylaluminum and ethylaluminum dichloride, triethylaluminum and sesquiethylaluminum chloride, diethylaluminum chloride and ethylaluminum dichloride, diethylaluminum chloride and sesquiethylaluminum chloride, triisobutylaluminum and sesquiethylaluminum chloride, n - Examples include octylaluminum dichloride and diisobutylaluminum chloride. Differences in these combinations have essentially no effect on the copolymer rubber, and the proportion of halogen needs to be within the range of the above formula.

If an organoaluminum compound with a m value of less than 1.1 is used, it is possible to produce a copolymer rubber with a high tensile strength of raw rubber, but the amount of cyclo-xane insoluble bone increases, and the present invention The desired copolymer rubber cannot be obtained.

When m is larger than 1.4, the cyclohexane-insoluble copper content decreases, but the tensile strength of the raw rubber decreases, making it impossible to obtain the copolymer rubber of the present invention.

The transition metal compound is a catalyst component consisting of a combination of a vanadium compound and at least one compound selected from transition metal compounds of groups 1 to 2 and group 2.

Vanadium compounds in this case include vanadium oxytrichloride: VOCIls, alkoxyvanadates such as n-butoxyvanadate diVO, (On-C4Hq
) 31 Isooctylvanadate: VO(0-is
o C4R9) s, octylvanade): VO
(OCB HIT) s f, nitrogen, and vanadium oxytrichloride and saturated aliphatic alcohols having 1 to 12 carbon atoms, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, and pentyl alcohol.

Examples include mixed components consisting of combinations with hexyl alcohol, octyl alcohol, etc.

Groups ■ to ■ combined with the vanadium compound and ■
Group transition metal compounds include Xa-0Ti (OR),
A titanium compound represented by Xa-, llZ r (OR
) Lucilcone compound represented by th, vanadium triacetylacetonate: ■ (ACAc)3. Vanadyl acetylacetonate): Vanadium compounds such as VO(AcAc)z, chromium chloride, chromium acetylacetonate: Cr(AcAc) 3. Octanoic acid romnic
Chromium compounds such as r(C7H+ s COO) 3,
Examples include nickel octoate: Ni (Ca H17COO) 2 , nickel naphthenate: Ni (naph) 2 , cobalt octoate, cobalt naphthenate, and the like.

Preferably Xa-T i (OR)ゎ, X4-m Z
r (OR) lll, V (A c A c) 3.

At this time, m is in the range of 0.5 to 3.5, and may be a mixture of two or more components within this range.

Further, OR is an alkoxy group having 1 to 12 carbon atoms, and X represents a halogen. Vanadium compounds and ■~■ groups and ■
The composition ratio with the group transition metal compound is 110.1 to 1/2
(molar ratio), preferably 110.2 to 1/
The range is 1.5 (molar ratio).

The catalyst system is disclosed in Japanese Patent Publication No. 43-28834, Japanese Patent Publication No. 9390/1982, Japanese Patent Publication No. 3360/1983,
JP-A-51-6291, JP-A-56-30415
It is also possible to use properties improving agents such as perchlorocrotonic acid ester, trichlorocrotonic acid ester, and trichloroacetic acid x ester, which are known from Japanese Patent Publication No.

Using a catalyst system as described above, using n-hexane as a polymerization solvent, polymerization temperature -10 to +50°C, pressure 0 to 10 kg/c
Ethylene/α-olefin/diolefin are brought into contact within the range of d. Molecular weight can be adjusted using hydrogen gas.

- The butyl rubber used in the strength tree invention is not particularly limited, and ordinary butyl rubber and/or halogenated butyl rubber can be used, but generally the degree of unsaturation is 0.5 to 3 mol% from the balance of processability and physical properties. Mooney viscosity (M L l
+8, too・. ) is used.

As described above, the olefin rubber composition of the present invention has the above-mentioned (
It is made up of a specific copolymer rubber that satisfies the conditions (e) and butyl rubber, and the weight ratio of the copolymer rubber and butyl rubber must be 5-95/95-5.

If the weight ratio of the copolymer rubber is less than 5% by weight, the characteristics of the copolymer rubber specified in the present invention cannot be obtained, resulting in unfavorable results in heat resistance, weather resistance, ozone resistance, etc.

On the other hand, if it exceeds 95% by weight, the characteristics of butyl rubber and/or halogenated butyl rubber cannot be obtained. That is, gas permeability, flexibility, and adhesiveness are poor.

The weight ratio is preferably 10-80/90-20.

Composition consisting of a blend of the ethylene-α-olefin-diolefin copolymer rubber of the present invention and butyl rubber and/or halogenated butyl rubber
・＠l,t 4f The above copolymerized 1" 1° and butyl rubber are triblended using a Banbury mixer, roll mill, etc., or suspended in a solution such as n-hexane, toluene, or methylene chloride. It can be obtained by a method such as solution blending or slurry blending, followed by recovering and drying the solid rubber using a conventional method.

The olefin rubber composition comprising the ethylene-α-olefin-diolefin copolymer rubber and butyl rubber and/or halogenated butyl rubber of the present invention further comprises ethylene-
Vinyl acetate copolymer, polyisobutylene, halogenated butyl rubber modified with chlorine or bromine, chloroprene, and ethylene-α-olefin other than those used in the present invention
Diolefin copolymers can also be blended.

The composition of the present invention may optionally contain fillers such as carbon black, white carbon, and calcium carbonate, colorants, blowing agents, flame retardants, and softeners.

Well-known additives can be added, such as thickeners, zinc oxide, stearic acid, vulcanizing agents, vulcanization accelerators, anti-aging agents, etc.
The crosslinking reaction is also sulfur vulcanization.

This can be carried out by quinoid vulcanization or the like.

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

The various test methods and measurement methods are as follows.

[Measurement method for cyclohexane insoluble matter]

3 g of raw rubber containing no compounding agents is cut into pieces with a side length of 1 fi or less, immersed in 100 ml of cyclohexane, and left to stand in a 30°C constant temperature bath for 48 hours. Thereafter, the undissolved bone was filtered through a stainless steel wire mesh of 80 sieve and dried in vacuum at 105°C for 1 hour, and then weighed.

The value obtained by dividing the weight of the insoluble copper content by the weight of the raw material rubber is defined as the amount of insoluble cyclohegysane (% by weight).

[Raw rubber tensile test method]

Maximum tensile stress σ of copolymer rubber specified in the present invention, □
(kgf/afl) and stress at 100% elongation σ1゜o (kgf/cn+) were calculated using JIS K2SO3 using a 21m thick test piece shown in Figure 2 of the attached drawing.
Based on the tensile test method, temperature 25°C1 tensile speed 500
Measured in m/min.

In this case, the stress when the elongation is 100% is σ. .

(kgf/c+A), and the maximum tensile stress up to breakage is the maximum tensile stress σmax (kgf/cJ
).

The test piece was made of raw rubber containing no compounding agents.
0g was preheated at 150°C heat press 10kgf/cl for 5 minutes, then left at 200kgf/cnl (7) pressure for 5 minutes and then 20°C press 200kgf/cl.
Cooled at c- for 15 minutes. Thereafter, it was aged at 25° C. for 10 hours or more, and dumbbell test pieces shown in FIG. 2 were punched out from the resulting two-fin-thick sheet. In this dumbbell test piece, the distance between 1 and 4 (5 and 8) shown in Figure 2 is 64f.
l, the interval between 1 and 5 (4 and 8) is 14 baskets, 9 and 11 (1
The interval between 0 and 12) is 5 cranes, and the interval between 2 and 13 (3 and 14) is 5 cranes.
．． The curve connecting 6 and 15.7 and 16) is a circular arc with a radius of 4 ml.

Note that the marked line when measuring elongation is the line connecting 17 and 18, and the line 19 and 20 drawn from the midpoint of the line connecting 1 and 4 to the position of 5 cranes on both sides.

[Measurement method of heat of fusion using differential scanning calorimeter] The differential scanning calorimeter is DuPont Model 910 Differential.
Calolimeter (hereinafter referred to as rDSCJ)
The recorder is a DuPont model 990 Thermal.
(using an eight analyzer).

The sample amount is 20±0.1μ, and the reference is α-alumina (Shimadzu DSC standard sample) 2
6.9■ was used.

First, measure the sample at room temperature, and set the Reference to D.
It is loaded into an SC and heated to +180°C, then cooled to -1000°C at a constant rate of 10°C per minute. Thereafter, analysis is performed at a heating rate of 20°C per minute. A typical SC curve obtained is shown in FIG.

WA%d)! :N(Dt, +'JjtJ!,'DIT(
D, k'1'=bz*1jtL, +,.

Ta.

The total crystal amount (W, ) is P-R-3-T-V-U in Figure 1.
-The part surrounded by P, the amount of crystals from 50 to 1000C (W2
) is the shaded area surrounded by R-3-VUR-R.

The amount of heat per unit chart area is calculated using indium (DuPont standard sample for DSC) as a reference material.

The amount of heat per 1 g of sample is determined based on the amount of heat when W+ and W2 are mixed with indium.

Each heat of fusion is Δ1 (IN (Total), ΔH.

It was expressed as (50-100).

Note that each point from O to ■ in FIG. 1 was determined as follows.

The intersection of the tangent to the baseline and the tangent to the endothermic peak below -50°C is defined as the 0 point as shown in FIG.

Drop a perpendicular line from the 0 point and calculate the distance h (m) using the following formula
Let the point be the Q point.

h (m) = 1.18X10-''

Draw a horizontal line from point Q and let the point of intersection with the DSC curve be point P. Draw a tangent from point P to the baseline at +140°C or higher, and let the point of contact be point T.

The intersections of the straight line connecting point P and point T with the perpendicular line above 50°C and the perpendicular line above 100°C are defined as point U and point ■, respectively.

The intersection points of the DSC curve and the perpendicular line above 50°C and the perpendicular line above 100°C are R point and 8 points, respectively.

[Methods for measuring other physical properties]

Mooney viscosity (M L I!a , too ・c ) was measured at a temperature of 100°C with 1 minute of preheating and 4 minutes of measurement.

Propylene content (wt%) measured by infrared absorption spectrum.

Iodine value is measured by titration method.

Tensile stress, tensile strength, elongation, tear strength (B type) are JI
Measured based on SK-6301.

The processability of the compounded rubber in a Banbury mixer was evaluated by visually evaluating the state of the compound after it was discharged from the Banbury mixer, the filler mixing state, the skin gloss, and the cohesiveness of the compound. The results are excellent, good, and fair.

Indicated by poor or poor.

The roll processability of compounded rubber is determined by winding the unvulcanized compound onto a 10-inch roll at a roll temperature of 50 °C ± 5 °C and a nip width of 21 nm, and determining the length of time required to tightly wrap the compound and the length of time required to wrap it tightly. The wrapping condition was evaluated based on whether or not the wrapping was tightly wound. The results were excellent.

Indicate as good, poor, or bad.

After the roll processability test, the surface condition of the sheet sample was evaluated based on the smoothness, gloss, etc. of the sheet surface, and the results were excellent and good.

Indicate as good, poor, or bad.

[Method of deformability test]

The compounded rubber was processed into a 50Φ Tsuru extruder (L/D-50, screw temperature 70°C, head temperature 100°C, screw rotation speed 3 Orpm) using a Garbe die.
Make an extrudate in the shape shown in the figure, and after 15 hours at 40°C
The shape retention rate was calculated using the following formula for the ratio of 1 to H2. Those with a shape retention rate of 90% or more were evaluated as good, and those with a shape retention rate of less than 90% were evaluated as poor.

[Method of crease test]

Roll the compounded rubber to make a sheet with a thickness of 150 mm.
Cut to a size of 50 mm.

Sprinkle talc on both sides of the sheet and fold it into quarters for 200
A load of g was applied. After 24 hours, creases were visually observed and evaluated according to the state of crease formation: good, fair, and poor.

Examples 1 to 3, Comparative Examples 1 to 3 Using the copolymer rubbers shown in Table 1, rubber compounds were prepared according to the formulations shown below. This rubber compound was prepared by mixing component CI) of the following compounding ingredients with a BR type banharry mixer at a rotor rotation speed of 60 rpm and a temperature of 50'C.
Kneaded for a minute and then held at 50°C.

Component (II) was then mixed for 5 minutes on a 111° mill on a 10 inch roll held at 50°C. The roll rotation speeds of the front and rear rolls were 22/28 rpm, respectively. The vulcanization conditions were 160° and 130 minutes, and the properties of the obtained vulcanizate are shown in Table 1.

Compounding prescription (parts by weight) *1: Comparative Example 1 of JSR Butyl #268 manufactured by Nippon Butyl ■ satisfies the requirements other than cyclohexane insoluble content, but the compounded rubber has a higher becyclohexane insoluble copper content than Example 1. The processing quality is poor.

In Comparative Example 2, the proportion of crystalline components having a melting point of 50 to 100°C is small, and as a result, the green strength of the raw rubber is low. In such a blend of copolymer rubber and butyl rubber, the processability of the compounded rubber is not only poor, but also the tear strength of the vulcanized rubber is reduced.

Comparative Example 3 has a relatively high α-olefin content, and the green strength of the raw rubber is lower than Comparative Example 2.
A value is smaller than B value. Such copolymer rubbers are good with almost no difference in processability, but are inferior to vulcanized rubber in tear strength.

Examples 4 and 5, Comparative Examples 4 and 5 Using the copolymer rubbers shown in Table 2, rubber compounds were prepared according to the formulation shown below. The kneading method is as per Example 1~
This was done in the same manner as in step 3.

Compounding recipe (parts by weight) *1; JSR Butyl #268 manufactured by Nippon Butyl ■2; Sonic process oil R- manufactured by Kyodo Oil ■]°000 Comparative example 4 using copolymer rubber with low tensile strength of raw rubber
was inferior to Example 4, which is the composition of the present invention, in roll processability, crease test, and shape retention. Furthermore, although the raw rubber has high tensile strength, Comparative Example 5, which uses a copolymer rubber with a high cyclohexane-insoluble copper content and an A value smaller than B value, is inferior to Example 5 in roll processability and crease test. . Furthermore, in Examples 4 and 5, the raw rubber tensile strength of the copolymer rubber is high, and the tensile strength of the unvulcanized compounded rubber is also high. This property resulted in good splicability during tube molding.

Oki Example 6, Comparative Example 6 Using the copolymer rubber shown in Table 3, a rubber compound was prepared according to the formulation shown below. The kneading method is as per Example 1~
This was done in the same manner as in step 3.

Formula (parts by weight) Zinc white 5t *3; Manufactured by Exxon ■ Chlorinated butyl #1068 Sulfur 0
．． 6'' In Comparative Example 6, the A value is smaller than the B value, and the proportion of the heat of fusion of the crystal having a melting point of 50 to 100°C measured by DSC is small. It can be seen that compared to Example 6, it is inferior in roll workability, tear strength, etc. The composition of Example 6 is suitable for the sidewalls of automobile tires.

1 Table 3 Effects of the Invention The olefin rubber composition of the present invention has a
- Reflecting the tensile strength characteristics of raw rubber of olefin-diolefin copolymer rubber, it is soft during processing of compounded rubber.
It has the property of increasing its strength when stress is applied.

Furthermore, mechanical strength such as tear strength increases when crosslinked with sulfur or the like. The fact that it is soft during processing allows it to be handled commonly in most applications, and brings good results in terms of power consumption, etc.

In addition, the property of compounded rubber that increases its strength when stress is applied in its unvulcanized state is generally expressed as green strength, and compounded rubber with high green strength is useful for preventing molded products from deforming, and for applications such as tubes. It is effective in improving splice strength and preventing cracks at creases.

The olefin rubber composition obtained by the present invention can be used for inner tubes of automobile tires, inner liners of tubeless tires, sidewalls, bicycle tires, inner tubes of various sports balls, waterproof sheets, anti-vibration for engine mounts or body mounts. Various anti-vibration rubbers including rubber, electrical insulating rubbers for various electrical equipment including electric wires, heat-resistant rolls, conveyors, sponges, etc.
It can be used as various hoses such as heat-resistant hoses, backings, etc. for automobiles and various other industrial parts.

[Brief explanation of drawings]

Figure 1 is a typical SC curve diagram, Figure 2 is the maximum tensile stress σ of the copolymer rubber, stress σ at 1X and 100% elongation,
. FIG. 3 is a front view of the test piece used to measure 0, and a cutaway view of the sample used to examine shape retention. Patent applicant: Japan Synthetic Rubber Co., Ltd. (Volunteer to write procedural amendments) July 13, 1980 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case 1982 Patent Application No. 1139592, Name of the invention Olefin rubber composition 3, Relationship with the person making the amendment Patent applicant address 2-11-24 Tsukiji, Chuo-ku, Tokyo Name (4)
17) Japan Synthetic Rubber Co., Ltd. Representative Hisashi Yoshimitsu 4, Agent ■107 Address Room 315, Palais Royal Akasaka 1bl, 2-17-54 Akasaka, Minato-ku, Tokyo Phone: 03 (584) 166
4 (1) In the second line of page 10 of the specification, "by weight ratio" should be changed to "by weight ratio: 80-40/20-60, preferably 75-45".
/25 to 55, and is corrected to ``. (2) r N i (Cs I
(+qCoo) 2J rN i (C? HISCOO
) z Correct to J. (3) On page 22, line 10 of the specification, “3gJ of raw rubber is”
Corrected to 0.3 gJ of raw rubber. that's all

Claims (1)

[Scope of Claims] ■, Ethylene-α that satisfies the following conditions (a) to (e)
- Consisting of an olefin-diolefin copolymer rubber and a butyl rubber and/or a halogenated butyl rubber, characterized in that the weight ratio of the copolymer rubber and the butyl rubber and/or the halogenated butyl rubber is 5 to 95/95 to 5. An olefin rubber composition. (a) The number of carbon atoms in α-olefin is 3 to 12, and the weight ratio of ethylene/α-olefin is 80 to 40/20 to 60.
, the bonding amount of diolefin units is 2 to 40° in terms of iodine value (b) The amount of insoluble matter when the copolymer rubber is dissolved in cyclohexane at 30°C is 20% by weight or less. (c) The maximum tensile stress (δwax) of copolymer rubber at 25°C is 20 to 150 kgf/cd, and 10
Tensile stress (σ100) at 0% elongation is 20kg
f/cJ or less. (d) σmax and σ of the copolymer rubber. The ratio of 0 (σmax
/ 6 too) as A, and the A value is greater than the B value given by the following formula. B=-0,18C+10.5 However, C is α-olefin content (wt%) (e) The heat of fusion of a crystal with a melting point of 50 to 100°C determined by a differential scanning calorimeter is the total heat of fusion. More than 6%. 2. The olefin rubber composition according to claim 1, which has an insoluble content of 15% by weight or less. 3. Patent claim 1 in which the α-olefin is propylene
The olefin rubber composition described in .