JPH0324147A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition improved in strengths and adhesiveness to a tackifier by mixing an alkyl (meth)acrylate/acrylonitrile copolymer with an alkyl (meth)acrylate/2-chloroalkyl vinyl ether copolymer rubber. CONSTITUTION:A copolymer rubber (A) is obtained by copolymerizing 100 pts.wt. (meth)acrylate having a 2-8C alkyl [e.g. ethyl (meth)acrylate] with 0.5-20 pts.wt. 2-chloroalkyl vinyl ether. A copolymer (B) is obtained by radical- copolymerizing 100 pts.wt. (meth)acrylate having a 4-18C alkyl [e.g. butyl (meth) acrylate] with 1-30 pts.wt. acrylonitrile in an organic solvent in the presence of a radical polymerization catalyst. 100 pts.wt. component A is mixed with 1-300 pts.wt. component B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rubber composition used as a base material for adhesive tapes, for example.

[Prior Art] Conventionally, moldings made of vinyl chloride resin (hereinafter referred to as moldings) have been attached to the bodies and bumpers of automobiles. This molding is attached to the side of the car body, and has the function of preventing scratches from contact with other objects when the door is opened, etc., as well as decoration, and is attached to the body via adhesive tape. The adhesive tape consists of an acrylic rubber base material coated with an adhesive.

[Problem to be solved by the invention] However, in order to wipe off the wax applied to a car, wax remover is used when washing the car,
Furthermore, when replenishing fuel such as gasoline, fuel may be accidentally spilled. In these cases, there is a problem in that wax remover or gasoline may adhere to the adhesive tape, reducing the adhesive strength between the acrylic rubber base material of the adhesive tape and the adhesive.

An object of the present invention is to provide a rubber composition that has sufficient strength and excellent adhesive strength with adhesives.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses carbon atoms of 4 to 18 carbon atoms.
A copolymer obtained by copolymerizing 1 to 30 parts by weight of acrylonitrile per iooi parts of acrylate or methacrylate having an alkyl group of 2-chloro Alkyl vinyl ether 0. 5-2
0 [1 to 300 parts by weight per 100 parts by weight of the copolymer rubber obtained by polymerizing part 1! A method of blending in a certain amount is adopted.

[Detailed explanation of the means] First, the copolymer will be explained.

Acrylates or methacrylates having an alkyl group having 4 to 18 carbon atoms (hereinafter, acrylates and methacrylates are collectively referred to as (meth)acrylates) include butyl (
meth)acrylate, isobutyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate,
Meth)acrylate, hexadecanol (meth)acrylate, stearyl (meth)acrylate, etc. can be used. If the number of carbon atoms in the alkyl group is less than 4, the resulting copolymer will be too hard, and if it exceeds 18, it is not practical.

The copolymer can be easily prepared by mixing 1 to 30 parts by weight of acrylonitrile per 100 parts by weight of this (meth)acrylate, adding a radical polymerization catalyst in an organic solvent, and heating for a predetermined time to perform radical polymerization. can be obtained.

If the blending ratio of acrylonitrile is less than 1 part by weight, the intermolecular force between the resulting copolymer and the copolymer rubber described below will be weak, resulting in a decrease in adhesive strength, and if it exceeds 30 parts by weight, the resulting copolymer rubber will be weak. The polymer loses its rubber elasticity.

The organic solvents used in the above polymerization include benzene, toluene, xylene, methyl acetate, ethyl acetate, isobrobyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobrobyl ketone, methyl isobutyl ketone, heptane, pentane, hexane, isooctane,
Examples include decane, n-hexane, cyclohexane, trichlorethylene, and the like. The type and amount of this organic solvent to be used are appropriately determined by a conventional method in radical polymerization.

This copolymer copolymerizes (meth)acrylate, which exhibits flexibility, and acrylonitrile, which exhibits rigidity, in a predetermined ratio, so it improves the cohesive force of rubber composite soles and improves the surface of rubber composite soles. Acrylonitrile increases the adhesive strength between the rubber compound and the adhesive applied thereon, and the acrylonitrile improves the oil resistance of the rubber assembly.

Next, the copolymer rubber will be explained.

As the (meth)acrylate having an alkyl group having 2 to 8 carbon atoms, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. can be used. If the number of carbon atoms in the alkyl group is 1, the resulting copolymer rubber will not have sufficient rubber elasticity, and if it exceeds 8, the copolymer rubber will lack toughness.

The alkyl group in the 2-chloroalkyl vinyl ether preferably has 2 to 10 carbon atoms. Specifically, 2-chloroethyl vinyl ether, 2-
Chloropropyl vinyl ether, 2-chlorobutyl vinyl ether, etc. can be used.

The blending ratio of this 2-chloroalkyl vinyl ether is
0.00 for 4 parts of 100EI of the above-mentioned (meth)acrylate having an alkyl group having 2 to 8 carbon atoms. It is in the range of 5 to 20 parts by weight. This blending ratio is 0. If it is less than 5 parts by weight, the resulting copolymer rubber will not have a sufficient crosslinked structure, resulting in low toughness and reduced adhesive strength, and if it exceeds 20 parts by weight, an excessively crosslinked structure will be formed and rubber elasticity will be lost.

The copolymer rubber used in the present invention contains 0.00 parts by weight of 2-chloroalkyl vinyl ether per 100 parts by weight of the above-mentioned (meth)acrylate having an alkyl group having 2 to 8 carbon atoms. 5-2
It is obtained by blending 0 parts by weight and copolymerizing according to a conventional method.

The rubber composition of the present invention can be obtained by removing the solvent from the solvent solution of the copolymer obtained as described above, and then blending it with the copolymer rubber. The proportion of the copolymer to the copolymer rubber is in the range of 1 to 300 parts by weight based on 100 parts by weight of the copolymer rubber. If it is less than 1 part by weight, the amount of copolymer bleed to the surface of the rubber composition is small, so there is little improvement in the adhesive force between the rubber composite sole and the adhesive, and if it exceeds 300 parts by weight, the amount of bleed increases. If too much, the copolymer forms a layer and peels off at that point.

[Function] By adopting the above method, a copolymer with excellent strength obtained by copolymerizing alkyl (meth)acrylate that exhibits flexibility and acrylonitrile that exhibits rigidity in a predetermined ratio is partially cross-linked with alkyl vinyl ether. Because it is blended with a strong copolymer rubber, the rubber composition itself has sufficient cohesive strength. The above-mentioned (meth)acrylic copolymer bleeds and the intermolecular force at the interface between the copolymer and the adhesive applied thereon improves, so that the rubber composite sole and the adhesive are bonded together. It is presumed that the adhesive force between the adhesive and the adherend to which the adhesive is commonly applied is improved.

[Examples 1 to 6 and Comparative Examples 1 to 6] Next, Examples embodying the present invention will be described in comparison with Comparative Examples. In addition, in each of the following examples, parts represent parts by weight.

(1) Manufacture of rubber-composed kaimono sheet After 100 parts of acrylate and acrylonitrile shown in Tables 1 and 2 are melted in an organic solvent of about 30% by weight (the organic solvents are 20% by weight of toluene and 80% by weight of ethyl acetate). A polymerization reaction was carried out at 70° C. for 15 hours using penzoyl peroxide (hereinafter referred to as BPO) as a polymerization catalyst. After the polymerization was completed, the organic solvent was removed to obtain an acrylic copolymer.

Also, acrylic resin shown in Table 1 and Table 2}10
1 and 2-chlorovinyl ether were mixed and polymerized under the same polymerization conditions as above to obtain a copolymer rubber. Next, the above copolymer was blended with 100 parts of this copolymer rubber in the proportions shown in Tables 1 and 2, and the mixture was heated at 160°C for 2 hours.
Press vulcanization was performed for 0 minutes. Then, it was left at room temperature for one day to obtain a rubber-composed sheet of samurai. The abbreviations in Tables 1 and 2 above have the following meanings. EAj ethyl acrylate BA: n-butyl acrylate 2EHAj 2-ethylhexyl acrylate (2) Adhesive To 100 parts of the acrylate shown in Table 3 below, a predetermined amount of carboxylic acid, 0.05 part of BP○, and 187 parts of ethyl acetate (8
(0%) and 46 parts (20%) of toluene were reacted at 70° C. for 15 hours in a nitrogen stream to obtain a copolymer solution. An ethyl acetate solution (solid content 70%) of the polyisocyanate shown in Table 3 was added to 100 parts of this copolymer solution to prepare an adhesive.

Table-3 The abbreviations in Table 3 above have the following meanings.

The abbreviations for acrylate are the same as in Table 1l above.

Carboxylic acid represents the following meanings.

AA: Acrylic acid MAA: methacrylic acid MA: Maleic acid Polyisocyanate has the following meanings.

MDI: 4,4'-diphenylmethane diisocyanate TDI: 2,4-}lylene diisocyanate XDI
:xylene diisocyanate NDI: 1,5-naphthalene diisocyanate (3
) Preparation of test piece After applying the adhesive on the rubber sheet, dry it at 100°C for 2 minutes, then apply another rubber sheet to the 25111×2
They were overlapped with a bonding area of 5 mm and pressed together under a load of 5 kg for 1 minute to obtain a test piece.

(4) Measurement of tensile shear strength
The tensile shear strength was measured under +tn conditions. The results are shown in Table 4. Table 4 The abbreviations of adhesives in Table 4 above represent the adhesives in Table 3 above. Moreover, * in the column of tensile shear strength indicates that the rubber composition has lost its rubber elasticity.

As can be seen from Table 4, in Examples 1 to 6 of the present invention, the tensile shear strength at room temperature was 7.0 to 7.0. The adhesive strength between the sheets of the rubber composition is as high as 8 kg/1, and the sheet made of the rubber composition has sufficient rubber elasticity. Therefore, the rubber assembly of each example is suitable as a base material for an adhesive tape used for adhering the molding of an automobile, for example.

On the other hand, when the blending ratio of 2-chloroethyl vinyl ether in the copolymer rubber is outside the scope of the present invention (Comparative Examples 1 and 2)
) or when the blending ratio of acrylonitrile in the copolymer is outside the range of the present invention (Comparative Examples 3 and 4), the tensile shear strength is low, or the tensile shear strength is high but the rubber composite has rubber elasticity. I will lose. In addition, when the blending ratio of the copolymer is outside the scope of the present invention (Comparative Examples 5 and 6),
Low tensile shear strength.

The rubber assembly sole of each of the above embodiments has sufficient rubber elasticity,
Moreover, the reason why it exhibits excellent tensile shear strength is thought to be as follows. In other words, both acrylic copolymer rubber and copolymer have sufficient rubber elasticity because acrylate, which is the main ingredient, is polymerized to a high molecular weight, and the surface of the rubber composition formed in the form of a sheet The acrylic copolymer blended into the mating material bleeds due to the difference in compatibility, and the intermolecular force between this copolymer and the acrylic adhesive applied to its surface is improved. This improves the adhesion between both sheets, and is sufficient because the rubber assembly itself is made of a copolymer rubber moderately crosslinked with 2-chloroethyl vinyl ether and a copolymer imparted with rigidity by acrylonitrile. It has a strong cohesive force.

[Effect of the Invention J The rubber composition of the present invention has sufficient strength itself and has excellent adhesive strength with the adhesive applied to its surface. The effect is that sufficient adhesive strength can be maintained even if a solvent is attached.

Claims (1)

[Claims] 1. A copolymer obtained by copolymerizing 1 to 30 parts by weight of acrylonitrile per 100 parts by weight of acrylate or methacrylate having an alkyl group having 4 to 18 carbon atoms, to acrylate or methacrylate having an alkyl group having 2 to 8 carbon atoms A rubber composition comprising 1 to 300 parts by weight of 2-chloroalkyl vinyl ether per 100 parts by weight of copolymerized rubber obtained by copolymerization with 0.5 to 20 parts by weight per 100 parts by weight.