JPS5887169A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive having excellent adhesive force, creep resistance and durability, by using, as a base polymer, a modified rubber obtd. by radical-polymerizing an ethylenically unsaturated monomer in the presence of a mixture of neoprene rubber and butyl rubber. CONSTITUTION:10-90wt% neoprene rubber is mixed with butyl rubber or its derivative such as chlorinated or brominated butyl rubber. 5-150pts.wt. ethylenically unsaturated monomer such as styrene, acrylonitrile or ethyl acrylate is radical-polymerized in the presence of 100pts.wt. above mixture and in the presence of 100pts.wt. above mixture and in the presence of a polymn. initiator such as cumene hydroperoxide or benzoyl peroxide. The resulting modified rubber is used as a base polymer. A tackifying resin such as rosin resin, petroleum resin or terpene resin is blended therewith to obtain the desired adhesive compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive composition using neoprene rubber and butyl rubber.

Adhesive compositions using neoprene rubber as a base polymer are widely used in various fields due to their excellent adhesive properties. There is a problem in which the peel adhesion strength decreases (7) as the adhesive composition progresses.The latter problem is especially noticeable when an adhesive sheet is made from this type of adhesive composition and stored in a rolled state over time. However, adhesive compositions using butyl rubber or its derivatives as a base polymer have excellent properties such as water resistance, moisture resistance, and durability. For this reason, it is widely used as an adhesive for anticorrosion tapes for steel pipes and as an adhesive for waterproof sheets.
It had poor adhesive strength, especially creep resistance, and could not be used as a general permanent adhesive.

Therefore, attempts have been made for a long time to use a mixture of neoprene rubber and butyl rubber or its derivatives to take advantage of the advantages of both, but both rubbers have poor compatibility and good adhesive properties cannot be obtained even when mixed as is. Ta. For this reason, several studies have been proposed to improve the above-mentioned compatibility, but no satisfactory results have been obtained yet.

The inventors have been conducting research on the above-mentioned mixed use for many years, and in the course of their research, they conducted a radical polymerization reaction of various ethylenically unsaturated monomers in a mixture of neoprene rubber and butyl rubber or its derivatives. As a result, a modified rubber was obtained in which the above monomer was graft-polymerized to a mixed rubber component, and it was discovered that when this modified rubber was used as a base polymer for an adhesive, the adhesive properties could be greatly improved. This led to the completion of this invention.

That is, in the present invention, in the presence of a mixture consisting of 10 to 90% by weight of neoprene rubber and 90 to 10% by weight of butylcom or its derivative, 5 to 150 parts by weight of an ethylenically unsaturated monomer is added to 100 parts by weight of the above mixture. The present invention relates to an adhesive composition characterized in that a modified rubber obtained by radical polymerization reaction in a proportion of parts by weight is used as a pace polymer.

As described above, in this invention, by modifying neoprene rubber and butyl rubber or its derivatives by the above-mentioned specific means, the problem of compatibility between the two rubbers is solved, and adhesive strength and creep resistance (holding force) are improved. The present inventors have succeeded in obtaining an adhesive composition that is excellent in both properties and durability such as water resistance, alkali resistance, and heat resistance. Also,
The adhesive composition of the present invention has good oral properties when made into an adhesive sheet, and hardly any decrease in peel adhesion is observed even when stored in a rolled state for a long period of time, making it suitable for application to adhesive sheets. The outstanding effect is that it becomes possible.

As the neoprene rubber used in this invention, any of those conventionally used in solution-type adhesives can be used, and specific examples of commercially available products include Neoprene AC, Neoprene W, and Neoprene WR manufactured by Showa Neoprene Co., Ltd.
Neoprene M-40 manufactured by Denki Kagaku Co., Ltd. is highly praised. Further, as the butyl rubber or its derivatives used in combination with the neoprene rubber, any conventionally known rubber can be used as described above, and includes a wide range of such rubbers as Enzybutyl 268 manufactured by Denki Kagaku Co., Ltd., chlorinated butyl rubber, brominated butyl rubber, and the like.

The mixing ratio of neoprene rubber and butyl rubber or its derivatives should be 10 to 90% by weight of neoprene rubber and 90 to 10% by weight of butyl rubber or its derivatives,
Preferably, the amount is 20 to 80% by weight of neoprene rubber and 80 to 20% by weight of butyl rubber or its derivative. one side is 10
If it is less than % by weight, the properties of the other rubber component become stronger, making it difficult to obtain an adhesive with excellent properties that takes advantage of the strengths of both components.

In this invention, the ethylenically unsaturated monomer is then subjected to a radical polymerization reaction in the presence of a mixture of neoprene rubber and butyl rubber or a derivative having the above mixing ratio, but this reaction is generally carried out in a bulk state or in a solution state. It will be held in Most preferred is reaction in a solution state.

As the ethylenically unsaturated monomer used in this reaction, styrene or its derivatives, acrylonitrile, methacrylonitrinoacrylic acid alkyl ester and methacrylic acid alkyl ester are preferable, and one or more of these are selected and used. It is better to do so. Specific examples of styrene derivatives include 4-methylstyrene,
2-methylstyrene, 4-tert-butylstyrene,
Examples of methacrylic acid alkyl esters include 2,4-dimethylstyrene, 2-hydroxymethylstyrene, and acrylic acid alkyl esters such as 2-butinope methacrylate, 3,3-dimethylbutyl methacrylate, and methacrylic acid. 3,3-dimethyl 2-butyl methacrylate, ethyl methacrylate, isobutino methacrylate, methyl methacrylate, hexadecinope methacrylate, inbornyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, inbornyl acrylate, methyl acrylate, acrylic ethyl acrylate, n-propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, inoctyl acrylate, isobutyl acrylate,
Examples include cyclohexyl acrylate.

In addition, in combination with the above monomers, vinyl acetate, vinyl ether, maleic acid monoalkyl ester, maleic acid dialkyl ester, fumaric acid dialkyl ester,
Acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, 2-methoxyethyl methacrylate, N,
Various ethylenically unsaturated monomers such as N-dimethylaminoethyl methacrylate, glycidyl methacrylate, and glycidyl acrylate can also be used.

It is also possible to use polyfunctional acrylic monomers such as trimethylolpropane trimethacrylate and polyether dimethacrylate in small amounts.

Among these various ethylenically unsaturated monomers, the higher the glass transition point of the homopolymer or copolymer (if two or more types are used), the better results can be obtained in terms of adhesive properties, especially holding power. It will be done.

In particular, a homopolymer (or copolymer) such as methyl methacrylate having a glass transition point of 300° or more is suitable. However, when it comes to acrylic acid alkyl esters or methacrylic acid alkyl esters,
Even with materials whose glass transition point is lower than the above, such as the aforementioned ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, improvement in adhesive properties can be expected.

The proportion of these ethylenically unsaturated monomers used should be within the range of 5 to 150 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the mixture consisting of neoprene rubber and butyl rubber or its derivatives. It is 100 parts by weight. 5
If the amount is less than 150 parts by weight, the modification effect due to the polymerization reaction will not be sufficiently obtained, and if it exceeds 150 parts by weight, a large amount of homopolymer or copolymer of ethylenically unsaturated monomers will be mixed in, resulting in neoprene rubber and butyl rubber. It is unsuitable because the properties of the compound or its derivative deteriorate.

The radical polymerization reaction uses a polymerization initiator and preferably a chain transfer agent, and is usually carried out at a temperature of about 55 to 100° C. in a nitrogen stream. Examples of the polymerization initiator used above include azobisisobutyronitrile, cumene hydroperoxide, di-tert-butyl peroxide, benzoyl peroxide, lert-butyl peroxybenzoate, lauroyl peroxide, methyl ethyl ketone peroxide, and cyclohexanone peroxide. There are azo compounds and organic peroxides. Organic peroxides give good results in terms of adhesive properties.

The amount of these polymerization initiators used is generally about 0.05 to 3 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer.

As the chain transfer agent, any conventionally known chain transfer agent such as thioglycol, thioglycolic acid, butyl quecabutan, and lauryl mercaptan can be used. When graft polymerizing ethylenically unsaturated monomers to neoprene rubber, butyl rubber, or their derivatives, gelation may occur depending on the conditions, and such gelation tends to adversely affect the applicability of adhesive compositions. . The use of chain transfer agents is effective in preventing said gelation. The amount used is usually about 0.005 to 0.05 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer.

It is desirable to carry out the radical polymerization reaction in a solution state using an organic solvent from the viewpoint of preventing gelation during polymerization and facilitating the polymerization operation, similar to the function of a chain transfer agent. That is, good results can be obtained in the polymerization operation by using a solvent with a large chain transfer constant or by adjusting the amount of the solvent. Specific examples of such organic solvents include toluene, benzene, xylene, hexane, heptane, methyl ethyl ketone, methanol, ethanol, and impropatol.

The modified rubber obtained as described above is used as a base polymer, and various tackifier resins such as rosin resin or its derivatives, petroleum resin, terpene resin, and phenol resin are added to this base polymer in an amount of about 20 to 100 parts by weight per 100 parts by weight of the base polymer. 1
The adhesive composition of the present invention is obtained by blending approximately 50 parts of the adhesive composition and, if necessary, by blending known additives such as softeners, fillers, crosslinking agents, pigments, and anti-aging agents. be able to.

This adhesive composition is known for its excellent adhesive properties, water resistance,
Due to its properties such as heat resistance, moisture resistance, and alkali resistance, it can be advantageously used in general adhesive applications, and can also be applied to adhesive sheets, making it extremely valuable industrially.

EXAMPLES Below, examples of the present invention will be described in more detail. The adhesive properties shown below were measured by the following method.

<Holding power> 50% of each adhesive composition was applied to a 25μ thick polyester film.
After applying it evenly to a thickness of 0 μm and drying it, apply it to a width of 25 mm,
Prepare a bamboo-length sample. 25m of this on a stainless steel plate
++ The length was pasted together, a load of 1.00 (l) was applied to the other end, and the time until it fell was measured.The measurement temperature was 4
The temperature was 0°C.

<Adhesive Strength> A laminate tape of a butyl rubber-based vulcanized comb sheet with a thickness of 1 μm and a butyl-based non-vulcanized comb sheet with a thickness of 0.3 am is prepared. After applying each adhesive composition to a thickness of 50 μm and drying, apply the unvulcanized rubber sheet surface of the above laminated tape (cut into 25 mm thick and 100 mm long) onto the coated surface. Prepare a sample by bonding 5 K90-rules in one reciprocating motion.
It was peeled off at a rate of 300 W/min in an atmosphere at .degree. C., and the adhesive strength at this time was measured.

<Water Resistant Adhesive Strength> The same sample as used for measuring adhesive strength was left in water at 20° C. for 7 days, and then measured in the same manner as for measuring adhesive strength.

<Heat-resistant adhesive strength> The same sample as for adhesive strength measurement was placed in an oven at 80°C.
After leaving it for a week, it was taken out and left in an atmosphere at 20°C for 2 hours. Hereinafter, the measurement was performed in the same manner as the adhesive force measurement.

<Peel Adhesion Strength> A 25μ thick polyester film is laminated on one side of the contact M sheet, and this is cut into 25τ width and 15° length. The surface of this sample opposite to the polyester film laminate surface was left on a stainless steel plate in an atmosphere of 20℃ for 20 minutes, and then peeled off at a speed of 300 mm/min in an atmosphere of 20℃ using a Schottspa complete tensile tester. Peel adhesion was measured.

Furthermore, in the following Examples and Comparative Examples, parts refer to parts by weight.

Example 1 5 parts of neoprene rubber (neoprene W as described above) and 50 parts of chlorinated butyl rubber are dissolved in 300 parts of toluene, and 30 parts of ethyl acrylate, 0.005 part of lauryl mercaptan and 0.0 parts of benzoyl peroxide are dissolved.
1 part was added and stirred for about 1 hour in a nitrogen stream. Then,
The temperature was raised to 90°C and the polymerization reaction was carried out for about 6 hours. 3 parts of magnesia, 40 parts of terpene resin, and 1 part of anti-aging agent were added to the obtained modified rubber solution to prepare an adhesive composition of the present invention.

This adhesive composition has a holding power of 785 minutes and an adhesion strength of 4.8
As of September 25th, the water resistant adhesive strength was 4.2 K9/25 trtrn, and the heat resistant adhesive strength was 5.4 K9/25 trtrn.

Comparative Example 1 Example 1 except that ethyl acrylate was not reacted.
An adhesive composition was prepared using the same formulation as above, but its holding power was 4 minutes, which was completely unacceptable for practical use.

Example 2 An adhesive composition was obtained in the same manner as in Example 1, except that 50 parts of styrene was used instead of ethyl acrylate. The holding power of this composition is 485 minutes, the adhesion strength is 4.4 instant/25cm, the water resistant adhesive strength is 4.6 to 9725 mm, and the heat resistant adhesive strength is 5.
It was 2K9/25 van.

Example 3 An adhesive composition was obtained in the same manner as in Example 1, except that 30 parts of acrylonitrile was used instead of ethyl acrylate. The holding power of this composition is 336 minutes, and the adhesive strength is 4.8~
/25 wLl, water resistant adhesive strength was 4.1/9/25, and heat resistant adhesive strength was 5.1 KSJ/25 morning.

Example 4 An adhesive composition was obtained in the same manner as in Example 1, except that 30 parts of methacriconitrile was used instead of ethyl acrylate. This composition has a holding power of 965 minutes and an adhesion strength of 4.5 minutes.
Water resistant adhesive strength was 4°2/9725, and heat resistant adhesive strength was 5.8/9/25.

Examples 5 to 10 Neoprene rubber (neoprene M-400 mentioned above) and chlorinated butyl rubber were mixed at a blending ratio of 300% as shown in the following table.
0.005 part of lauryl mercaptan and methyl methacrylate and benzoyl peroxide in the proportions shown in the table below were added thereto, and a polymerization reaction was carried out in the same manner as in Example 1.

To each of the obtained modified rubber solutions, 20 parts of rosin modified resin, 15 parts of phenol resin, 3 parts of magnesia and 1 part of zinc white were added to obtain an adhesive composition of the present invention. The adhesive properties of this composition were as shown in the following table.

Moreover, using each of the adhesive compositions of Examples 7 and 8, 2
Two types of adhesive sheets were prepared by coating both sides of a 02/- nonwoven fabric to a thickness of 60 μm. As a result of examining the initial peel adhesive strength of this sheet and the peel adhesive strength after being left at room temperature in a rolled state for 6 months, it was found that in Example 7, the initial peel adhesive strength was 1.90Of/25.
mm, 2,050 if left for 6 months? , 725 won
In Example 8, the initial value was 1.750 f/25 mm, and after being left for 6 months, it was 1,700 g/25 mm.

Comparative Example 2 An adhesive composition was prepared using the same formulation as in Example 9 except that methyl methacrylate was not reacted, but its holding power was 3 minutes, which was completely unacceptable for practical use.

Example 11 20 parts of neoprene rubber (neoprene AC described above), 80 parts of brominated butyl rubber, 30 parts of methyl methacrylate, 5 parts of acrylic acid, 20 parts of butyl acrylate, 300 parts of toluene
parts, 100 parts of xylene, 0.2 parts of cumene hydroperoxide and 0.2 parts of lauroyl peroxide,
The mixture was placed in a three-necked flask and stirred well for about 2 hours in a nitrogen stream. Then, the temperature was raised to 90°C and a polymerization reaction was carried out for about 10 hours.

The adhesive composition of the present invention was prepared by adding 5 parts of magnesia, 2 parts of zinc white, 2 parts of anti-aging agent, 10 parts of coumaron resin, and 40 parts of petroleum resin to the obtained modified rubber solution. The holding power of this adhesive composition is 1.000 minutes or more, and the adhesive strength is 4.
．． To 2! 9/25 shell, water distribution adhesive strength is 5.1 Kg725
mm, and the heat-resistant adhesive strength was 5.8 Kp/25 holes.

Claims (3)

[Claims] (1) In the presence of a mixture consisting of 10 to 90% by weight of neoprene rubber and 90 to 10% by weight of butyl rubber or its derivative, 5 to 150 parts by weight of an ethylenically unsaturated monomer is added to 100 parts by weight of the above mixture. 1. An adhesive composition characterized in that the base polymer is a modified rubber obtained by radical polymerization reaction in a proportion. (2) Claim No. 1 in which the ethylenically unsaturated monomer contains at least one selected from styrene or its derivatives, acrylonitrile, methacrylonitrile, acrylic acid alkyl esters, and methacrylic acid alkyl esters. The adhesive composition described in . (3) The adhesive composition according to claim (1) or (2), wherein an organic peroxide is used as an initiator in the radical polymerization reaction.