JPH0662820B2 - Method for producing olefin rubber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an olefin-based rubber which has excellent heat resistance and can be hot-air vulcanized.

2. Description of the Related Art In general, polyolefin-based synthetic rubbers are widely applied to electrical insulating materials, radiator hoses, weather mat trips, etc. because of their excellent electrical and mechanical properties.

Furthermore, in recent years, in order to improve the heat resistance of this polyolefin-based synthetic rubber, it has been carried out to add organopolysiloxane to the rubber component, for example, Japanese Patent Publication Nos. 55-30741 and 5
5-39248, 55-39261, 57-17011, 58-13
It is proposed in Japanese Patent No. 093.

However, the heat resistance of the polyolefin synthetic rubber to which the organopolysiloxane is added is not sufficient, and foams by hot air vulcanization like the peroxide vulcanization type rubber composition of the comparative example described later, and the elastic body is formed. It was difficult to obtain, and it was difficult to expand its applications.

Therefore, it has been desired to further improve the heat resistance of the polyolefin synthetic rubber.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a polyolefin-based rubber which has excellent heat resistance and is easily cured by hot air vulcanization to give a good elastic body.

Means and Actions for Solving the Problems As a result of extensive studies conducted by the present inventor to achieve the above object, the ethylene-propylene-diene copolymer alone or 60% by weight or more thereof does not contain a silicon atom-bonded hydrogen atom. A rubber composition containing a mixture of 40% by weight or less of organopolysiloxane and platinum or a platinum compound is mixed with an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule. Add 0.7 to 5 hydrogen atoms bonded to the silicon atom of the organohydrogenpolysiloxane described above per 1 diene and alkenyl group of the polymer and the organopolysiloxane containing no silicon-bonded hydrogen atom. Enables the above organohydrogenpolysiloxane to act as a cross-linking agent, and to be easily hardened by hot air vulcanization. And then it found that a rubber composition having excellent heat resistance can be obtained to give good elastic, the present invention has been accomplished.

Therefore, the present invention provides (1) an ethylene-propylene-diene copolymer 60 to 100
A mixture of 1% by weight and 0 to 40 parts by weight of an organopolysiloxane having no hydrogen atoms bonded to silicon atoms and having at least two alkenyl groups in one molecule, (2) Silicon in one molecule An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to each atom, which gives 0.7 to 5 hydrogen atoms bonded to a silicon atom per one diene and alkenyl group in component (1), and (3) 2) A method for producing a polyolefin rubber, which comprises vulcanizing a rubber composition containing platinum or a platinum compound in a catalytic amount at 150 to 200 ° C with hot air.

Hereinafter, the present invention will be described in more detail.

The first essential component of the rubber composition of the present invention is an ethylene-propylene-diene copolymer.

Here, as the ethylene-propylene-diene copolymer, those having a propylene content of 40 to 70% by weight, particularly 40 to 60% by weight are preferable, and the diene monomer is, for example, ethylidene norbornene, dicyclopentadiene, 1 ,
4-hexadiene and the like are common. Further, this copolymer preferably has an iodine value of 1-40, particularly 5-30.

As such a copolymer, a commercially available polyolefin rubber component can be used, and specifically, EP22 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Esprene 567 (manufactured by Sumitomo Chemical Co., Ltd.), EPT3045 ( Mitsui Petrochemical Industry Co., Ltd., E
P33 (manufactured by Japan Synthetic Rubber Co., Ltd.) and the like are exemplified.

In the present invention, it is preferable that the ethylene-propylene-diene copolymer is mixed with an organopolysiloxane having no hydrogen atom bonded to a silicon atom.

As the organopolysiloxane, the following general formula (1) (In the formula, R'is an identical or different unsubstituted or substituted monovalent hydrocarbon group, particularly a monovalent hydrocarbon having 1 to 10 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group. Group, vinyl group, allyl group, alkenyl group such as butenyl group, phenyl group, aryl group such as tolyl group, benzyl group, aralkyl group such as β-phenylethyl group, and a part of hydrogen atom of these groups or A chloromethyl group, a 2-cyanoethyl group, a 3,3,3-trifluoropropyl group, etc., all of which are substituted with a halogen atom or a cyano group, and a is 1.9
It is a positive number between 9 and 2.02. ), And at least two or more vinyl groups in one molecule,
Those having an alkenyl group such as an allyl group and a butenyl group are preferably used. In this case, the group other than the alkenyl group is preferably one having a methyl group of 50 mol% or more.
If the methyl group content is less than 50 mol%, the cured rubber may have poor low temperature properties.

The average degree of polymerization of the organopolysiloxane of the above formula (1) is preferably 500 to 8,000.

Specifically as such an organopolysiloxane,
Examples include methyl vinyl polysiloxane, methyl vinyl phenyl polysiloxane, methyl (3,3,3-trifluoropropyl) polysiloxane, and the like.

The mixing ratio of the ethylene-propylene-diene copolymer and the organopolysiloxane is 100% by weight of the copolymer.
-60 wt%, preferably 100-70 wt%, and organopolysiloxane 0-40 wt%, preferably 0-30 wt%. If the mixing ratio is outside the above range, the strength of the cured rubber will be reduced.

Next, in the present invention, an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule is blended as the second essential component.

In this case, the organohydrogenpolysiloxane acts as a cross-linking agent, and for example, the following general formula (2) (However, in the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group excluding the same or different aliphatic unsaturated groups, particularly one having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group or a butyl group. Groups such as alkyl groups, phenyl groups, aryl groups such as tolyl groups, benzyl groups, aralkyl groups such as β-phenylethyl groups, cycloalkyl groups such as cyclohexyl groups, b is a positive number from 0.002 to 1.0, and c Is a positive number from 1.99 to 2.02, b
+ C is 1.992 to 3.0. ), And an organohydrogenpolysiloxane having at least two hydroxyl groups in one molecule is preferably used.

Specific examples of such an organohydrogenpolysiloxane include compounds represented by the following structural formulas.

[L is an integer of 2 to 10, m and n are integers of 0 to 10, respectively. ] The blending amount of the second component is an amount that gives 0.7 to 5, especially 1 to 3 hydrogen atoms bonded to the silicon atom of the siloxane, per one diene and alkenyl group in the first component. It is preferable. A sufficient crosslinking effect may not be obtained with an amount that gives less than 0.7 hydrogen atoms.
In some cases, improvement in properties may not be observed even if the amount is added in excess of the number.

Furthermore, the platinum or platinum compound of the third essential component of the present invention is
A catalyst for advancing the above-mentioned addition reaction between the first component and the second component, such as platinum, platinum black, chloroplatinic acid, a complex salt of chloroplatinic acid with an olefin or an aldehyde, and an alcohol-modified chloroplatinic acid. And so on.
The amount of platinum or platinum compound used may be a catalytic amount, but may be appropriately increased or decreased depending on the composition so that the curing rate due to the reaction between the first component and the second component is desirable. The amount of platinum is usually 1 ppm to 1% by weight with respect to the amount of the first component used.

In the rubber composition of the present invention, in addition to the above-mentioned essential components, optional components for adjusting the physical properties of the cured product, if necessary, such as fumed silica, precipitated silica, aluminum silicate, quartz powder, fused quartz powder, Fillers such as diatomaceous earth, calcium carbonate, titanium dioxide, carbon black, antiaging agents, ultraviolet absorbers, colorants and the like can be added. The blending amount of the filler is 100% of the first component.
It is preferably 500 parts or less with respect to parts, and when it is more than 500 parts, the cured product may be hard and brittle.

Furthermore, the rubber composition of the present invention can be obtained by kneading the predetermined amounts of the above-mentioned first to third components with a two-roll mill, a kneader, a Banbury mixer, etc. When a required amount of synthetic oil such as liquid paraffin or Lucant HC40 (manufactured by Mitsui Petrochemical Industry Co., Ltd.) is added, the viscosity of the composition is lowered and the processability can be improved.

Thus, in the present invention, a polyolefin-based rubber is obtained by vulcanizing the above rubber composition with hot air. In this case, the temperature of the hot air vulcanization is 150 to 200 ° C., and the present invention applies the hot air vulcanization of 150 to 200 ° C. to the polyolefin rubber composition, so that the polyolefin rubber composition can be efficiently used in a short time. Not only can it be vulcanized, but the rubber molded article can be continuously vulcanized and molded. The vulcanization time is usually 5 to 10
A rubber cured product having good elasticity can be obtained by heat treatment for a minute.

EFFECTS OF THE INVENTION According to the present invention, a polyolefin-based rubber having excellent heat resistance and good elasticity in hot air vulcanization can be efficiently provided in a short time.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

[Examples 1 to 3, Comparative Example] Polyolefin synthetic rubber EP22 (Nippon Synthetic Rubber Co., Ltd.)
Manufactured by Iodine Co., Ltd. 22), (CH ₂ ═CH) (CH ₃ ) SiO unit 0.5 mol%, (CH ₃ ) ₂ SiO unit 99.5 mol% Methyl vinyl having an average degree of polymerization of 8000 with both ends blocked by hydroxyl groups. Polysiloxane, silica Aerosil 20 with a surface area of 200 m ² / g 20
0 (manufactured by Nippon Aerosil Co., Ltd.) is 2 at the ratio shown in Table 1.
After blending using this roll, it was dissolved in toluene to give a 10% rubber-toluene solution.

Next, the obtained 10% rubber-toluene solution was added to the following formula (2). Organohydrogenpolysiloxane represented by 1
Parts, chloroplatinic acid 5% isopropyl alcohol solution 0.05
Part, then mixed and teflon coated depth 0.5mm
The sample was poured into the metal case. 180 hours after air drying
It was put in an oven at ℃ and heat-treated for 10 minutes to obtain a sheet having a thickness of 0.3 mm. All the obtained sheets were elastic bodies without voids.

Also, for comparison, 1 part of dicumyl peroxide was added instead of the organohydrogenpolysiloxane and chloroplatinic acid, and the same treatment was carried out, but this sample foamed and an elastic body could not be obtained. It was

Further, the mechanical properties of the molded thin film were measured according to JIS K-6301. The results are also shown in Table 1.

From the results shown in Table 1, the rubber composition containing the peroxide (Comparative Example) did not undergo hot air vulcanization sufficiently and a cured product was not obtained, but the organohydrogenpolysiloxane of the formula (2) was mixed. The rubber compositions (Examples 1 to 3) were
It was found that the hot-air vulcanization allowed the crosslinking reaction to proceed rapidly to obtain a good cured product.

[Examples 4 to 6] Polyolefin synthetic rubber [Espren 567 (Sumitomo Chemical Co., Ltd., propylene content 46% by weight, iodine value 5)], (CH ₂ = CH) (CH ₃ ) SiO unit 0.5 mol %, (C
₆ H ₅ ) ₂ SiO units 10 mol%, (CH ₃ ) ₂ SiO units 89.5 mol% with an average degree of polymerization of 8000 Methyl vinyl phenyl polysiloxane, HAF carbon using the two rolls in the ratio shown in Table 2. After compounding, it was dissolved in toluene to give a 10% rubber toluene solution.

Next, the following formula (3) was added to the obtained 10% rubber-toluene solution. Organohydrogenpolysiloxane represented by 1
After the addition of parts, molding was performed in the same manner as in Example 1 to obtain a thin film, and the characteristics thereof were evaluated. The results are also shown in Table 2.

From the results in Table 2, it was confirmed that the rubber composition of the present invention gives a good cured product by hot air vulcanization.

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Claims (1)

[Claims] (1) An ethylene-propylene-diene copolymer (60 to 100% by weight) and an organopolysiloxane having no silicon atom-bonded hydrogen atom and having at least two alkenyl groups in one molecule. (2) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule, based on one diene or alkenyl group in the above component (1). A polyolefin characterized by hot air vulcanization at 150 to 200 ° C. of a rubber composition containing 0.7 to 5 hydrogen atoms bonded to elementary atoms and (3) a catalytic amount of platinum or a platinum compound. Of producing rubber.