JPS6356273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to adhesive compositions. Various adhesives have been used for various purposes depending on their properties. For example, hot melt adhesives consist only of non-volatile components and do not contain solvents or water, so while they have the property of completing adhesion within a few seconds or less after application, they have the disadvantage of poor heat resistance. Of course, heat resistance can be improved by incorporating a resin with a high softening point into the adhesive, but this naturally requires a high bonding temperature, so it may not be applicable depending on the adherend. be. Furthermore, although a short open time is an advantage of hot melt adhesives as described above, a longer open time may be preferable depending on the application. For example, when bonding a large area such as a building material panel, conventional hot melt adhesives have a short open time, so it is necessary to reheat the adhesive after applying it to the panel. On the other hand, adhesives have a very long open time in contrast to hot melt adhesives, and have the property of being able to bond simply by applying pressure at room temperature, but they also have the disadvantage of poor heat resistance. The present invention was made in view of the above-mentioned drawbacks of hot-melt adhesives and pressure-sensitive adhesives.Like hot-melt adhesives, they consist only of non-volatile components, but unlike pressure-sensitive adhesives, they can be used at room temperature or heated. An object of the present invention is to provide an adhesive composition that increases adhesive strength and heat resistance over time after pressure-sensitive bonding, and has a long open time. The adhesive composition of the present invention has (a) a general formula RSiY ₃ (in the formula, R is an organic group having an olefinic double bond, and Y is a hydrolyzable organic group).
(b) at least one polymer selected from polyolefin resins, synthetic rubbers, and polyolefin resins graft-polymerized with the above-mentioned silane compounds; do. In the above silane compound to be graft-polymerized to the liquid rubber, R is an organic group having an olefinic double bond, preferably a hydrocarbon group having an olefinic double bond. Specific examples include a vinyl group, an allyl group, a butenyl group, a cyclohexenyl group, and a vinyl group is particularly preferred. In addition, the above organic group has an ester bond in the molecule,
It may have an ether bond and/or a hydroxyl group, and an example of such an organic group is CH ₂ =C(CH ₃ )
The group COO(CH ₂ ) ₃ - can be mentioned. In the above silane compound, Y is a hydrolyzable organic group, for example, an alkoxy group such as a methoxy group, an ethoxy group, a butoxy group, an acyloxy group such as a formyloxy group, an acetoxy group, a propionoxy group, (CH ₃ ) ₂ C=NO−, C ₂ H ₅ C
Oxime groups such _as ( _CH3 )C=NO-, ( _C6H5 ) _2C =NO-, substituted amino groups such as alkylamino and arylamino groups, e.g. methylamino, ethylamino, and phenylamino groups. The following groups can be mentioned. In the present invention, Y may be any other suitable organic group as long as it can be hydrolyzed, but is preferably an alkoxy group.
Therefore, particularly preferred silane compounds in the present invention are vinyltrimethoxysilane and vinyltriethoxysilane. Examples of the liquid rubber to which the above-mentioned silane compound is graft-polymerized include liquid polybutadiene, polyisoprene, poly-1,3-pentadiene, and polychloroprene, and liquid polybutadiene and polyisoprene are preferred. Note that the term "liquid" herein includes semi-solid paste. In order to graft-polymerize a silane compound onto these liquid rubbers, the liquid rubber and the silane compound are heated and kneaded in the presence of a free radical generator according to a known method. Usually, 0.05 to 1 part of a free radical generator is added to 100 parts of liquid rubber (hereinafter, parts mean parts by weight), and at a temperature of about 140°C or higher,
In addition, the mixture is heated and kneaded at a temperature within a range where the liquid rubber does not decompose. Free radical generators include benzoyl peroxide, dicumyl peroxide,
Examples include organic peroxides such as lauroyl peroxide, peresters such as t-butyl peracetate and t-butyl perbenzoate, and azo compounds such as azobisisobutyronitrile, but dicumyl peroxide is particularly preferably used. It will be done. In the present invention, the ratio of the silane compound to 100 parts of liquid rubber is 0.5 to 30 parts.
parts, preferably 1 to 20 parts, particularly preferably 5 to 15 parts
Department. Next, the polyolefin resin used in the present invention means an olefin homopolymer, a copolymer, and a copolymer of olefin and other functional monomers, such as polyethylene, polypropylene, ethylene-acetic acid. Vinyl copolymers, saponified products thereof, ethylene-acrylic ester copolymers, ethylene-acrylic acid copolymers, ethylene-propylene-acrylic acid copolymers, ethylene-vinyl acetate-acrylic acid copolymers, etc. However, polyethylene and ethylene-vinyl acetate copolymers are preferably used. Also, what is synthetic rubber?
Unlike the liquid rubber, it refers to a rubbery synthetic polymer that is solid at room temperature, and examples include isoprene rubber, butadiene rubber, styrene-isoprene rubber, styrene-butadiene rubber, isoprene-isobutylene rubber, and ethylene-propylene rubber. Styrene-isoprene rubber and styrene-butadiene rubber are preferred. In addition, a polyolefin resin in which a silane compound is graft-polymerized is a polyolefin resin graft-polymerized with the above-mentioned silane compound, preferably polyethylene and/or ethylene-vinyl acetate copolymer, under the same conditions as explained for liquid rubber. means something that has been done. The adhesive in the present invention preferably contains 10 to 90 parts of liquid rubber graft-polymerized with a silane compound,
Contains 5 to 80 parts of at least one kind of polymer selected from polyolefin resins, synthetic rubbers, and polyolefin resins grafted with silane compounds, particularly preferably 30 to 70 parts of the former and 20 to 60 parts of the latter.
Contains part. Furthermore, in the present invention, in order to increase the tackiness during adhesive application, a silane compound that is commonly used in the adhesive composition is used as long as it is compatible with the adhesive composition and the silane compound does not react with the graft-polymerized liquid rubber. It may contain the tackifier used, such as a terpene resin, a plasticizer or wax for improving workability, and other stabilizers, fillers, colorants, etc. As described above, the adhesive of the present invention contains liquid rubber in which a silane compound is graft-polymerized, so if it is left at room temperature after bonding, it will not absorb moisture in the atmosphere or adsorbed water on the surface of the adherend. As a result, the silane compound is hydrolyzed and the liquid rubber is crosslinked with each other, thereby increasing the adhesive strength and improving the heat resistance over time. However, in order to cause the above-mentioned crosslinking to occur quickly after adhesive construction, in the present invention, the adhesive is a silanol condensation catalyst for 100 parts of a liquid rubber graft-polymerized with a silane compound.
It is preferable to contain 0.01 to 10 parts. As already known, the silanol condensation catalyst is a catalyst for promoting the hydrolysis and mutual bonding of silane compounds in the presence of moisture. This crosslinks the graft-polymerized liquid rubber, thereby increasing the adhesive strength after bonding over time and increasing the heat resistance. Such silanol condensation catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, zinc naphthenate, zinc caprylate, cobalt naphthenate, diethylamine, dibutylamine, mineral acids, fatty acids, and the like. , particularly dibutyltin laurate. The adhesive of the present invention comprises a liquid rubber graft-polymerized with a silane compound, the polymer such as a polyolefin resin, and, if desired, the catalyst, tackifier, plasticizer, stabilizer, filler, etc. It is manufactured by uniformly mixing under heating using the conventional method.
As mentioned above, the silane compound is hydrolyzed by moisture, so production is carried out in an atmosphere free of moisture.
For example, it is desirable to carry out in dry air, and
It is also desirable to store it in a dry atmosphere. The adhesive of the present invention is in the form of a semi-solid paste at room temperature, and is applied to an adherend at room temperature or, if necessary, heated to increase fluidity. When applied to an adherend, unlike conventional adhesives, it is highly adhesive and has a long open time, so it can be bonded without the need for heat press even when the bonding area is large, for example. Moreover, the initial adhesive strength is almost the same as that of conventional adhesives, but if left at room temperature,
As mentioned above, since crosslinking and curing progresses due to atmospheric moisture, etc., it has far greater heat resistance than conventional hot-melt adhesives and pressure-sensitive adhesives. The present invention will be explained below with reference to Examples. Example 1 Liquid isoprene rubber (manufactured by Kuraray Co., Ltd., Kuraprene)
LIR-30) 100 parts, vinyltriethoxysilane 10
and 0.2 parts of dicumyl peroxide,
Graft polymerization was carried out at a temperature of 140 to 150°C for 30 minutes to obtain a silane grafted liquid isoprene rubber. Separately, 100 parts of ethylene-vinyl acetate copolymer with a vinyl acetate content of 28% and a melt index of 400, 10 parts of vinyltrimethoxysilane and dicumyl peroxide.
0.2 parts were mixed and graft polymerized for 30 minutes at a temperature of 140 to 150°C to obtain a silane grafted ethylene-vinyl acetate copolymer. The two kinds of graft polymers thus obtained were prepared in the following composition together with a terpene resin, a silanol condensation catalyst, and an antioxidant at 100 to 110°C in dry air.
An adhesive composition was prepared by melt-kneading at a temperature of . Silane-grafted liquid isoprene rubber 20 parts Silane-grafted ethylene-vinyl acetate copolymer
40 parts terpene resin (Yasu Yuki Kogyo Co., Ltd., Polyster #2115) 40 parts dibutyltin dilaurate 1 part antioxidant (Sumitomo Chemical Co., Ltd., Sumilizer)
BHT) 1 part Example 2 In the same manner as in Example 1, 10 parts of vinyltrimethoxysilane was graft-polymerized to 100 parts of liquid isoprene rubber (Kuraprene LIR-50), and this graft polymer was used to form an adhesive of the following composition. A drug was prepared. Silane grafted liquid isoprene rubber 20 parts Ethylene-vinyl acetate copolymer (same as Example 1) 40 parts Terpene resin (same as Example 1) 40 parts Dibutyltin dilaurate 1 part Antioxidant (same as Example 1) 1 part Example 3 In the same manner as in Example 1, 10 parts of vinyltrimethoxysilane was graft-polymerized to 100 parts of liquid isoprene rubber (Kuraprene LIR-50), and this graft polymer was polymerized with the following components at a temperature of 120 to 130°C. An adhesive composition was prepared by melt-kneading. Silane-grafted liquid isoprene rubber 20 parts styrene-isoprene rubber (Ciel, Califrex TR-1107) 40 parts terpene resin (same as Example 1) 40 parts plasticizer (Ciel, Cielflex #451)
5 parts dibutyltin dilaurate 1 part stabilizer (zinc dibutyl dithiocarbamate) 2 parts Comparative Example 1 The following components were heated and melted to prepare an adhesive by a conventional method. Ethylene-vinyl acetate copolymer (same as Example 2) 40 parts Liquid isoprene rubber (Kuraprene LIR-50) 20 parts Terpene resin (same as Example 1) 40 parts Antioxidant (same as Example 1) 1 part Comparative Example 2 A hot melt adhesive was prepared by heating and melting the following components in a conventional manner. Ethylene-vinyl acetate copolymer (same as Example 2) 40 parts alicyclic saturated hydrocarbon resin (Arakawa Chemical Co., Ltd., Alcon P-70) 40 parts Microwax (Mobil Oil Company, Mobil Wax #) 2305) 20 parts Antioxidant (same as Example 1) 1 part The open time at 20°C of each adhesive prepared as described above is shown in the table below. Also, apply 100g/each of these adhesives to the plywood board at a temperature of approximately 130℃.
Apply on the surface at a ratio of m ² and glue a 25 mm wide canvas.
The initial adhesive strength (Kg) at 20°C and 80°C and the adhesive strength at 20°C and 80°C after being left for 7 days at a temperature of 20°C and a humidity of 60% were determined by a 90° peel test. The results are shown in the table. Clearly, the adhesive of the present invention has a much longer open time and better heat resistance than conventional hot melt adhesives. 【table】

Claims (1)

[Claims] 1 (a) A silane compound represented by the general formula RSiY ₃ (in the formula, R is an organic group having an olefinic double bond, and Y is a hydrolyzable organic group) An adhesive composition comprising: a graft-polymerized liquid rubber; and (b) at least one polymer selected from polyolefin resins, synthetic rubbers, and polyolefin resins graft-polymerized with the silane compound. 2. The adhesive composition according to claim 1, wherein the silane compound is vinyltrimethoxysilane and/or vinyltriethoxysilane. 3. The adhesive composition according to claim 1 or 2, wherein the liquid rubber is liquid polyisoprene and/or liquid polybutadiene. 4 Silane compound 0.5 per 100 parts by weight of liquid rubber
4. The adhesive composition according to claim 1, wherein the liquid rubber is graft-polymerized using ~30 parts by weight. 5. The adhesive composition according to any one of claims 1 to 4, wherein the polyolefin resin is polyethylene or an ethylene-vinyl acetate copolymer. 6. The adhesive composition according to any one of claims 1 to 4, wherein the synthetic rubber is styrene-isoprene rubber or styrene-butadiene rubber. 7. The adhesive composition according to claims 1 to 6, which is graft-polymerized using 0.5 to 30 parts by weight of a silane compound per 100 parts by weight of a polyolefin resin. 8 (a) 10 to 90 parts by weight of liquid rubber graft-polymerized with a silane compound, and (b) 5-80 parts by weight of at least one kind of polymer selected from polyolefin resins, synthetic rubbers, and polyolefin resins graft-polymerized with silane compounds. The adhesive composition according to any one of claims 1 to 7, characterized in that it contains parts by weight. 9. The adhesive composition according to any one of claims 1 to 8, which contains a silanol condensation catalyst. 10. The adhesive composition according to claim 9, wherein the silanol condensation catalyst is dibutyltin dilaurate.