JPH0113748B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to polyurethane adhesives, more specifically,
In particular, it relates to polyurethane adhesives useful for adhesively bonding polyvinyl chloride sheets or films to aluminum plates that have been subjected to a special coating treatment (Triclean Finishing System (TFS) treatment). Problems to be Solved by the Invention Recently, aluminum plates have been widely used as various building materials, but they suffer from problems such as corrosion over time, so they are coated with a special paint to improve durability. being done. However, from a design standpoint, this specially painted (TFS) aluminum plate is used as a construction material with a polyvinyl chloride sheet or film laminated with a woodgrain pattern, if desired. , there is a problem with adhesion. As a result of intensive research to provide an adhesive that is effective for adhering such specially coated aluminum plates and polyvinyl chloride sheets or films, the present inventor discovered that thermoplastic polyester urethane, which is often used in solution-type polyurethane adhesives, By grafting a specific alkoxysilyl compound having an unsaturated bond to rubber and combining it with a polyisocyanate compound as a crosslinking agent,
The inventors discovered that the adhesive exhibits excellent adhesive strength and completed the present invention. Structure and Effects of the Invention In other words, the present invention provides a modified reaction product obtained by grafting a radically reactive alkoxysilyl compound having an unsaturated bond onto a thermoplastic polyester urethane rubber (hereinafter simply referred to as urethane rubber), and a crosslinking agent. The present invention provides a polyurethane adhesive characterized in that it is made of a polyisocyanate compound. The urethane rubber used in the present invention is an elastomer having a urethane bond in its molecular chain, and usually contains polybasic acids (terephthalic acid, isophthalic acid, phthalic acid, succinic acid, adipic acid, azelaic acid,
sebacic acid, etc.) and dihydric alcohols (ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, trietherene glycol,
Polyethylene glycol, propylene glycol, etc.) are subjected to a condensation reaction, and the resulting saturated polyester resin with terminal hydroxyl groups is combined with active hydrogen groups and diisocyanate compounds (tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc.). , cyclohexylmethane diisocyanate, etc.) in approximately equivalent amounts. The alkoxysilyl compound used in the present invention is a radically reactive compound having an unsaturated bond, and
An alkoxysilyl compound having an acroxy group or a methacrolyxy group represented by the following formula [], or an alkoxysilyl compound having a vinyl group or allyl group represented by the following formula [] or [], or a mercapto group represented by the following formula [] Included are alkoxysilyl compounds. [In the formula, R ¹ is hydrogen or methyl, A is a divalent hydrocarbon group, R ₂ is alkyl having 1 to 4 carbon atoms, R ³
is methoxy, ethoxy, acetoxy or propenyloxy, and a is 0 to 3] Specifically, r-methacryloxypropyltrimethoxysilane, r-methacryloxypropylmethyldimethoxysilane, r-acryloxypropyltrimethoxysilane , r-methacryloxyalkylalkoxysilanes such as r-acryloxypropylmethyldimethoxysilane, 2-styrylethyltrimethoxysilane, or r-acryloxyalkylalkoxysilanes, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxy silane, vinylalkoxysilanes or allylalkoxysilanes such as vinylmethyldiacetoxysilane, vinyldimethylethoxysilane, vinylmethyldiethoxysilane, allyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-mercaptopropylmethyldimethoxy Examples include alkoxysilanes having a mercapto group such as silane, r-mercaptopropyltrimethoxysilane, and β-mercaptoethyltriethoxysilane.
Seeds or mixtures of two or more types are used. The amount used is usually selected within the range of 1 to 50 parts, preferably 5 to 30 parts, per 100 parts (by weight, hereinafter the same) of urethane rubber. If it is less than 1 part, it will not exhibit adhesion to specially coated aluminum, and if it exceeds 50 parts, insoluble precipitates will tend to form in the modification reaction product. The modified reaction product in the present invention is produced by subjecting the urethane rubber to a graft reaction with a predetermined proportion of an alkoxysilyl compound in the presence of a polymerization initiator in a conventional manner. For example, the above urethane rubber can be treated with a suitable organic solvent such as ester type (ethyl acetate, butyl acetate, etc.), ketone type (methyl ethyl ketone, cyclohexanone, acetone, etc.), aromatic type (toluene, xylene, benzene, etc.), chlorine type (triclene, etc.). , methylene chloride, etc.)
etc., then add a polymerization initiator (benzoyl peroxide, azobisisobutyronitrile, kyumene hydroperoxide, t-butyl hydroperoxide, potassium persulfate, ammonium persulfate, etc.) and an alkoxysilyl compound. Mix and heat under reflux at 60-100℃ for over 1 hour.
Preferably, the graft reaction is carried out for 2 to 4 hours. In addition to the alkoxysilyl compound used in the present invention, other monomers such as acrylic acid,
Acrylic esters (methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid 2-
Ethylhexyl, isobutyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1,4-butanediol diacrylate, 1,6- hexanediol diacrylate, pentaerythritol triacrylate, etc.), methacrylic acid and methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate) , isodecyl methacrylate, lauryl methacrylate, lauryl-tridecyl methacrylate, tridecyl methacrylate, cetyl-stearyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate,
Benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, t-methacrylate
butylaminoethyl, glycidyl methacrylate,
(tetrahydrofurfuryl methacrylate, etc.), and one or more of acrylamide, acrylonitrile, acrolein, vinyl acetate, styrene, N-methylolacrylamide, vinylpyridine, maleic anhydride, vinylpyrrolidone, butadiene, etc. in appropriate amounts. You can also. The crosslinking agent in the present invention is a polyisocyanate compound that is used as a crosslinking agent for ordinary chloroprene solvent adhesives and urethane rubber adhesives.
Any material that has a high vapor pressure, low toxicity to the human body, and is easy to handle may be used. For example, triphenylmethane triisocyanate (manufactured by Bayer)
Desmodur R, 20% methylene chloride solution), triisocyanate phenyl thiophosphate (Bayer
Desmodur RF, 20% methylene chloride solution),
Examples include isocyanate compounds obtained by adding trimethylolpropane to tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd., 75% ethyl acetate solution), special grade MDI (Millionate MR, manufactured by Nippon Polyurethane Co., Ltd.), and the like. In such a polyisocyanate compound, the active hydrogen group of the hydroxyl group in the molecular chain of the modified urethane rubber reacts with the isocyanate group, resulting in crosslinking, so it contributes to improving adhesive strength, and the amount used is determined by the amount of the modified reaction product. 2 to 100 parts per 100 parts of solid content, preferably 5 to 100 parts
It is sufficient to select 50 copies. The polyurethane adhesive according to the present invention can be put to practical use as a two-component adhesive comprising the above modification reaction product and a crosslinking agent. In addition, if necessary in the modified reaction product. Unmodified urethane rubber, rosin resin or rosin resin (pentaerythritol ester of rosin resin, glycerol,
ester, hydrogenated rosin resin, methyl ester of hydrogenated rosin resin, triethylene glycol ester, pentaerythritol ester, rosin ester, polymerized rosin resin, glycerol ester of polymerized rosin resin, etc.). good. It is particularly useful for laminating specially coated aluminum sheets and polyvinyl chloride sheets or films, but is not limited to this.
It can also be used for adhesion between other metal materials, plastic materials, wood, etc., lamination processing of plastic films, etc. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Examples 1 to 6 and Comparative Example 1 Urethane rubber (manufactured by Dainippon Ink and Chemicals Co., Ltd., Pandex T-5205) in the parts shown in Table 1, an organic solvent (MEK: methyl ethyl ketone), and methyl methacrylate (MMA) as a graft monomer. ), acrylonitrile (AN), r-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.,
KBM-503), 2-styrylethyltrimethoxysilane (manufactured by Chitsuso Corporation, PSX083), polymerization initiator (BPO: benzoyl peroxide), polymerization inhibitor (HQ:
Hydroquinone) was accurately weighed in a glass container and heated to 80°C.
The graft reaction was carried out for 3 hours under reflux, and urethane rubber (Pandex T-
5205) Add and mix 500 parts and MEK 2000 parts to create the adhesive main component. A polyurethane rubber adhesive is prepared by blending 200 parts of a crosslinking agent (Desmodur R) with this. Comparative Example 2 In Comparative Example 1, a polyurethane adhesive is prepared in which 5 parts of KBM-503 are post-added without reacting. Test Example Examples 1 to 6 were applied to adherends made of polyvinyl chloride sheet leather products (manufactured by Sunstar Giken Co., Ltd., Orsia) and TFS-treated aluminum plates in the shape of a strip of 20 mm wide x 100 mm long. Or comparative examples 1 and 2
Each adhesive was applied at approximately 100 g/m ² and bonded together after drying with the solvent to prepare an adhesive test piece. After curing and curing this test piece for 1 day, autograph determined the peel strength at 180° at a head speed of 50 mm/min (normal peel strength) and the peel strength after immersion in water at 60°C for 10 days (water resistant peel strength). Furthermore, a 24-hour creep test is conducted by applying a load of 100 g to one end of the sheet in a heated atmosphere of 110° C., and the peeling length (heat-resistant creep property) is measured. The test results are shown in Table 1.

[Table] From the results in Table 1, the adhesive of the present invention according to the example is
It is recognized that the adhesion between the TFS-treated aluminum plate and the polyvinyl chloride sheet and the heat creep resistance are superior to the comparative example.

Claims (1)

[Scope of Claims] 1. A polyurethane characterized by comprising: a modified reaction product obtained by grafting a radically reactive alkoxysilyl compound having an unsaturated bond onto a thermoplastic polyester urethane rubber; and a polyisocyanate compound as a crosslinking agent. glue. 2 The alkoxysilyl compound has the formula: [expression] or [In the formula, R ¹ is hydrogen or methyl, A is a divalent hydrocarbon group, R ² is alkyl having 1 to 4 carbon atoms, R ³
is methoxy, ethoxy, acetoxy, or propenyloxy, and a is 0-3. ] One or two selected from the group of compounds represented by
The adhesive according to item 1 above, which is a mixture of more than one species. 3. The adhesive according to item 1, wherein the modification reaction product is obtained by grafting 1 to 50 parts by weight of an alkoxysilyl compound to 100 parts by weight of thermoplastic polyester urethane rubber. 4. The adhesive according to item 1 above, in which unmodified thermoplastic polyester urethane rubber coexists.