JPH0655858B2 - Low-temperature crosslinkable halogen-containing rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a halogen-containing rubber composition which can be cross-linked at low temperature.

(Prior Art) Halogenated polyethylene, halogenated ethylene-α-olefin copolymer rubber, chlorosulfonated polyethylene,
Halogen-containing rubber-like materials such as epichlorohydrin rubber have excellent weather resistance, adhesiveness, flame retardancy, heat resistance, and oil resistance. The sealant, adhesive, adhesive (adhesive) tape, etc. are used to make full use of these characteristics.

(Problems to be solved) Therefore, in the above-mentioned applications, practical cross-linking properties are often required in a low temperature region of about room temperature.

For example, as a crosslinking agent for the above-mentioned halogen-containing rubber,
Mercapto group-substituted-s-triazine derivatives such as 2,4,6-trimercapto-s-triazine, thioureas such as ethylenethiourea, polyfunctional amines such as triethylenetetramine, and dicumyl peroxide. Various organic peroxides are known.

However, all of these crosslinking agents require a high temperature of 130 ° C. or higher in order to perform crosslinking. Therefore, it is not suitable for the above-mentioned sealants, adhesives, adhesive tapes, etc., especially for applications requiring low-temperature crosslinkability.

Therefore, the present invention has a technical object to develop a halogen-containing rubber composition that can be cross-linked at low temperature.

(Means for Solving Problems) The halogen-containing rubber composition of the present invention contains a silane coupling agent in a proportion of 0.1 to 50 parts by weight per 100 parts by weight of the halogen-containing rubber-like substance. This is an important feature.

(Function) According to the present invention, by adding a silane coupling agent, as will be apparent from Examples described later, 100
It is possible to carry out the crosslinking in a low temperature region of ℃ or less.

Since such a crosslinking reaction rapidly proceeds in a low temperature region of 100 ° C. or less, the present invention allows easy crosslinking even in a low temperature region.

(Preferred Embodiment of the Invention) Halogen-Containing Rubber-like Material As the halogen-containing rubber-like material used in the present invention, halogenated polyethylene, chlorosulfonated polyethylene, halogenated ethylene-α-olefin copolymer rubber, and epichlorohydrin rubber are preferable. is there.

As the halogenated ethylene-α-olefin copolymer rubber, ethylene and α-olefins having 3 to 10 carbon atoms,
For example, a chlorinated or brominated copolymer of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-decene and the like is used.

As the epichlorohydrin rubber, not only epichlorohydrin homopolymer rubber, but also epichlorohydrin / ethylene oxide copolymer rubber, epichlorohydrin / allyl glycidyl ether copolymer rubber and / or epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer rubber Can be used.

The above-mentioned halogen-containing rubber-like material preferably contains chlorine atom or bromine atom in an amount of 0.1 to 50% by weight, particularly 10 to 40% by weight.

When the halogen content is less than this range, the characteristics of halogen-containing rubber such as oil resistance, adhesiveness, and flame retardancy tend to be insufficient, and when the halogen content is higher, characteristics such as cold resistance and processability are likely to occur. There is a tendency to become unsatisfactory in.

These halogen-containing rubber-like materials have a viscosity (25 ° C)
From 1 poise to Mooney viscosity ML _{1 + 4} (100 ° C) of 15
The viscosity at 25 ° C is 1
Those in the range of 0 to 10,000 poise are preferred.

Silane coupling agent As the silane coupling agent which is a constituent component of the rubber composition of the present invention, an amino group, a mercapto group, an organic functional group selected from a ureido group, an alkoxy group bonded to silane, an acetoxy group and the like. A silane compound having a hydrolyzable group is preferably used.

That is, this silane coupling agent has the following general formula: In the formula, X, X ′, and X ″ are hydrolyzable groups and are an alkoxy group or an acetoxy group, Y is an amino group, a mercapto group, or a ureido group, and R is —R ₁ —, Or a divalent atomic group selected from R ₁ —O—R _{4 n} , wherein R ₁ , R ₃ and R ₄ represent an alkylene group or a phenylene group, R ₂ represents H or an alkyl group, R ′ And R ″ are alkyl groups, and n is a number from 1 to 5.

Specifically, γ-aminopropyltrimethoxysilane,
γ-aminopropyltriethoxysilane, β-aminoethyltrimethoxysilane, β-aminoethyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyl Examples thereof include methyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane and the like.

When such a silane coupling agent having an organic functional group and a hydrolyzable group is compounded with the above-mentioned halogen-containing rubber-like material, the compound reacts with water in a low temperature region, for example, a temperature of 90 ° C. or lower. The cross-linking is performed.

Preparation of rubber composition The rubber composition of the present invention is obtained by reacting the halogen of the rubber-like material described above with the organic functional group of the silane coupling agent in the absence of water to bond the silane coupling agent to the halogenated butyl rubber. Can be obtained.

The reaction is carried out, for example, by adding the compound at a temperature of 100 to 170 ° C.
It can be easily performed by heating for about 0 minutes.

In the present invention, the silane coupling agent to be reacted with the halogen-containing rubber-like material is the halogen-containing rubber-like material 100.
It is used in an amount of 0.1 to 50 parts by weight, especially 5 to 20 parts by weight.

When the compounding amount of the silane coupling agent is larger than the above range, excellent properties such as oil resistance of the halogen-containing rubber-like material are lost, and when the compounding amount is small, crosslinking is performed in a low temperature range. The object of the present invention is not achieved.

The rubber composition thus obtained does not undergo crosslinking in the absence of water and maintains flexibility, so that it does not allow moisture to pass through, a canister for a sealing agent, or polyethylene, polyvinylidene chloride, or the like. Store in a bag made of plastic film with a low moisture permeability,
When necessary, the product can be used by unpacking it.

Crosslinking When the rubber composition of the present invention is emptied of a can or bag and taken out into the atmosphere immediately before use, it absorbs moisture in the atmosphere and rapidly crosslinks to exhibit properties as a crosslinked rubber.

Although this coupling reaction is very fast, the diffusion of water into the rubber is rate-determining, and the influence of atmospheric temperature is small. For example, a sheet having a thickness of 0.5 mm loses its plasticity in about 3 hours even at a temperature of 5 ° C. when water is sufficiently supplied.

The organic functional group of the silane coupling agent used in the present invention has a role of binding the silane coupling agent to the halogenated rubber by reacting with the halogen in the halogen-containing rubber-like material as described above. Since it can be carried out in a fully equipped factory, the reaction speed does not matter so much. However, the storage stability of the hydrolyzable alkoxyl group and acetoxy group bound to the other functional group, silane, and the hydrolysis reaction and the subsequent dehydration condensation reaction between silanol groups are It is necessary that it does not adversely affect the deacetic acid reaction.
From such a viewpoint, an amino group, a mercapto group, and a ureido group are effective as the organic functional group of the silane coupling agent, which is well suited to the above purpose.

Other compounding agent The rubber composition of the present invention may be compounded with a catalyst for the condensation reaction of the silane coupling agent in order to improve the crosslinking rate.

As the catalyst for accelerating the condensation reaction, metal organic acid salts such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, iron stearate, ammonium carbonate, organic amines and the like are effective.

Although such catalysts differ depending on their type, in general,
It is used in a proportion of 1.0 to 3 parts by weight per 100 parts by weight of the halogen-containing rubber.

Further, the rubber composition of the present invention may be blended with a mercapto group-substituted triazine derivative, thioureas, polyfunctional amines, organic peroxides and the like used for crosslinking a halogen-containing rubber. .

Further, in the present invention, various compounding agents known per se according to the intended use of the crosslinked product, for example, a reinforcing agent for rubber, a filler, a softening agent, a plasticizer, a tackifier, an anti-softening agent, and aging. Inhibitors, ultraviolet absorbers, antioxidants, antiozonants, lubricants, flame retardants, foaming agents, coloring agents, antifungal agents, etc. may be added in known amounts.

(Function and Effect) The halogen-containing rubber composition obtained as described above can be cross-linked in the low temperature range of outside temperature to 100 ° C. in an environment where moisture exists, such as in the air or in water, so that a sealant, It can be effectively used as an adhesive tape, a repair material for rubber products, an adhesive that dissolves in a solvent, an anticorrosion tape, a roof waterproof sheet, and the like.

Examples will be shown below, but it goes without saying that the present invention is not limited thereto.

Example Chlorinated ethylene / 1-butene copolymer rubber [ethylene unit content 90 mol%, chlorine content 27 wt%, ML _{1 + 4} (100
C) 80, specific gravity 1.05 g / cc], a silane coupling agent, and dibutyltin laurate at a ratio shown in Table 1 by an open roll at room temperature, and then heated at 150 ° C for 20 minutes to prepare each of A to E. A composition according to the invention and comparative compositions F and G were obtained. A sheet having a thickness of 2 mm was prepared from the obtained composition, and was immersed in warm water at 70 ° C. for crosslinking. The degree of swelling in cyclohexane was measured as a measure of the degree of crosslinking. The degree of swelling was measured by immersing a sample of 2 mm × 10 mm × 10 mm in cyclohexane at 25 ° C. for 72 hours, and showing the rate of change in volume after immersion with respect to volume before immersion. The results are shown in Table 2.

Example 2 Ingredients H. of the present invention were kneaded at room temperature with the proportions shown in Table 3 at room temperature and heated at 150 ° C for 20 minutes.
Various rubber compositions I. and comparative controls J to L were obtained. The obtained rubber composition is formed into a sheet having a thickness of 2 mm, and the temperature is 50 ° C.
The samples were allowed to stand in warm water of 50 ° C. and in an oven at 50 ° C. to examine changes with time in mechanical properties. Tensile strength (T
_B: kg / cm ²⁾ and elongation (E _B:%) according to JIS according to JIS K6301
Tensile speed of the test piece prepared using No. 3 dumbbell is 500
Measured in mm / min. The results are shown in Table 4.

Claims (4)

[Claims] 1. A halogen-containing rubber composition containing a halogen-containing rubber-like material and a silane coupling agent, wherein the silane coupling agent is a halogen-containing rubber-like material 10.
A low-temperature crosslinkable halogen-containing rubber composition, characterized in that it is contained in an amount of 0.1 to 50 parts by weight per 0 parts by weight. 2. The rubber composition according to claim 1, wherein the halogen-containing rubber-like material contains chlorine or bromine in an amount of 0.1 to 40% by weight. 3. The rubber composition according to claim 2, wherein the halogen-containing rubber-like material is a halogenated polyethylene, a halogenated-α-olefin copolymer rubber, epichlorohydrin rubber, or chlorosulfonated polyethylene. 4. A silane coupling agent having an organic functional group selected from an amino group, a mercapto group, and a ureido group, and a hydrolyzable group selected from an alkoxy group bonded to silane or an acetoxy group. The rubber composition according to claim 1, wherein