JPH0130874B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to polyurethane adhesives, more specifically,
It is an organic solution type product that exhibits excellent adhesive strength especially when at least one of the adherends is a soft polyvinyl chloride sheet or film, and also improves the heat aging resistance and creep resistance of the adhesive strength. This invention relates to polyurethane adhesives. Conventional technology and problems to be solved Conventionally, solution-type polyurethane adhesives have excellent flexibility and plasticizer resistance, so they have been used for molded products such as polyvinyl chloride sheets or films containing a large amount of plasticizer. It is used in a wide range of applications as an all-purpose adhesive because it bonds well with other plastic materials, wood, metal, etc.
However, it has been desired to develop an adhesive that can prevent adhesive deterioration due to plasticizers migrating from the adherend to the adhesive interface, has excellent heat resistance, and has improved performance. Therefore, the present inventors conducted intensive research to develop an adhesive that would be less affected by the plasticizer contained in the adherend, and found that they dissolved thermoplastic polyester urethane rubber in an organic solvent and added acrylic resin to the rubber. We have developed a polyurethane adhesive with excellent plasticizer-resistant adhesion, which is made by grafting a monomer for plasticizer, adding and dissolving chlorinated rubber as the main component of the adhesive, and combining it with an isocyanate compound as a crosslinking agent. A patent application is already pending (patent application filed in 1982).
(See No. 201499). The inventors of the present invention further investigated the developed adhesive and found that if a specific polyoxyalkyl ether polyol is added to the main component of the adhesive, the adhesiveness to plasticizer-containing flexible polyvinyl chloride agents can be improved. The present inventors have discovered that it is possible to use a thermoplastic polyester urethane rubber that has improved properties, particularly heat aging resistance and thermal creep resistance, and is not grafted, and has completed the present invention. That is, the present invention provides thermoplastic polyester urethane rubber (hereinafter referred to as urethane rubber) and/or
or urethane rubber grafted with at least one selected from the group of acrylic acid, acrylic ester, methacrylic acid, and methacrylic ester (hereinafter referred to as graft rubber), chlorinated rubber, two or more in one molecule. polyoxyalkylene ether polyol having an ether group of
and a polyurethane adhesive characterized by comprising an isocyanate compound as a crosslinking agent. Structure and Effects of the Invention The urethane rubber that can be used as a component in the present invention is an elastomer having urethane bonds in its molecular chain, and usually includes 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, triethylene glycol, polyethylene glycol,
Propylene glycol, etc.) are subjected to a condensation reaction, and the obtained saturated polyester resin having terminal hydroxyl groups is combined with the active hydrogen groups and diisocyanate compounds (tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc.).
It is a linear polymer that has been reacted with the isocyanate groups of cyclohexylmethane diisocyanate, etc. in approximately equivalent amounts. Such urethane rubber can be prepared using suitable organic solvents, such as ester-based (ethyl acetate, butyl acetate, etc.), ketone-based (methyl ethyl ketone, cyclohexanone, acetone, etc.), aromatic (toluene, xylene, benzene, etc.), chlorine-based (triclene, chloride, etc.). Easily dissolved in methylene, etc.). In the present invention, a monomer to be grafted onto the urethane rubber (hereinafter referred to as a graft monomer)
is acrylic acid, acrylic ester (e.g. methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isobutyl acrylate, 2-ethoxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, acrylic 2-hydroxyethyl acid, 2-hydroxypropyl acrylate, 1,4
-butanediol diacrylate, 1,6-hexanediol acrylate, pentaerythritol triacrylate, etc.), methacrylic acid and methacrylic acid esters (such as 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, methacrylate Cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, etc. ), and at least one selected from these groups is used. Particularly preferred are functional ones having at least one of a hydroxyl group, a carboxyl group, a glycidyl group, and an amino group. In addition to such monomers, acrylamide, acrylonitrile, acrolein, vinyl acetate, styrene, N-methylolacrylamide, vinylpyridine, maleic anhydride, vinylpyrrolidone, butadiene, etc. can also be used in combination. The above-mentioned graft rubber that can be used as a component in the present invention is produced by grafting a graft monomer to urethane rubber in a conventional manner. For example, after dissolving the urethane rubber in an organic solvent, a radical-generating polymerization initiator (benzoyl peroxide, azobisisobutyronitrile, kyumene hydroperoxide, t-butyl hydroperoxide, potassium persulfate, ammonium persulfate) salt, etc.) and the graft monomer, and heat under reflux at 60 to 100°C for over 1 hour.
Preferably, the graft polymerization is carried out for 2 to 4 hours. In such a graft, the ratio of urethane rubber and graft monomer is 100 parts of urethane rubber (parts by weight,
It is desirable to use 10 to 70 parts of the graft monomer (the same applies hereinafter), and to graft at least 10 to 30 parts of the graft monomer. The monomer to be grafted is
If it is less than 10 parts, the adhesion by grafting will not be improved, and if it exceeds 30 parts, the solution viscosity may increase or gelation may occur during polymerization. The above polymerization initiator is usually 0.3 to 100 parts of urethane rubber.
It is used in an amount of 1.0 part, but if it is too little, excessive polymerization rate and polymerization time will be required, and if it is too much, the polymerization will be good, but the viscosity of the solution will increase and gelation may occur. The graft rubber thus obtained is used in a 5-30% solution of the organic solvent. The chlorinated rubber, which is a component in the present invention, refers to natural rubber or synthetic rubber that is reacted with chlorine. ”,
"CR-10", "CR-20", "CR-40", "CR-40"
"CR-90" and "CR-150" are commercially available, and synthetic rubber products include chlorinated polyethylene and chlorinated polypropylene, which are made by chlorinating polyethylene and propylene, and chlorinated polypropylene, which is made from polyvinyl chloride and chlorinated polyethylene. Examples include vinyl chloride. These chlorinated rubbers dissolve well in aromatic, ester, and ketone organic solvents. The amount of chlorinated rubber used is 0.5 per 100 parts of normal ingredients.
You can choose between ~20 copies. In the present invention, the polyoxyalkylene ether polyol having two or more ether groups in the molecule, which is a component, is a low molecular weight active hydrogen compound having two or more active hydrogens (e.g. ethylene glycol, propylene glycol, butylene glycol, 1,6 -Diols such as hexanediol, glycerin, trimethylolpropane, 1,
Triols such as 2,6-hexanetriol, ammonia, methylamine, ethylamine,
Amines such as propylamine and butylamine)
Random or block copolymer polyoxyethylene-propylene polyol obtained by ring-opening polymerization of propylene oxide and ethylene oxide in the presence of one or more of Tetramethylene glycol,
One having a molecular weight of 500 to 10,000 and having 2 to 3 hydroxy groups in one molecule is desirable. The amount of polyoxyalkylene ether polyol to be used can be selected within the range of 5 to 20 parts, preferably 8 to 15 parts, per 100 parts of the normal component. Since the compatibility with the contained plasticizer etc. is improved, the adhesive strength can be improved. In the present invention, the component crosslinking agent is an isocyanate compound that is used as a crosslinking agent for ordinary chloroprene solvent-based adhesives and urethane rubber adhesives, and has a high vapor pressure, low toxicity to the human body, and is easy to handle. For example, triphenylmethane triisocyanate (Bayer
Triisocyanate phenyl thiophosphate (DesmodurRF, manufactured by Bayer, 20% methylene chloride solution), isocyanate compound made by adding trimethylolpropane to tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd.) Coronate L, 75% ethyl acetate solution), special grade MDI (Millionate MR manufactured by Nippon Polyurethane Co., Ltd.), etc. In such isocyanate compounds, the active hydrogen group of the hydroxyl group in the molecular chain of the component reacts with the isocyanate group, resulting in crosslinking, so it contributes to improving adhesive strength.
The number may be selected to be 3 to 50 copies per 100 copies. The polyurethane adhesive according to the present invention is usually put to practical use in the form of a two-component organic solution consisting of an adhesive main component consisting of the above-mentioned components, and a crosslinking agent as a component. In addition, as a tackifying resin for the main component of the adhesive, for example, rosin resin or rosin derivative (pentaerythol ester of rosin resin, glycerol ester, hydrogenated rosin resin, methyl ester of hydrogenated rosin resin, Appropriate amounts of triethylene glycol ester, pentaerythol ester, rosin ester, polymerized rosin resin, glycerol ester of polymerized rosin resin, etc. may be blended. Not only can it be used to bond molded objects such as polyvinyl chloride sheets or films containing a large amount of plasticizer with plastic materials, wood, or metal materials, but also to bond plastic films, etc., which is the main application of polyurethane adhesives. It is also useful as an adhesive for lamination processing.Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.Examples 1 to 7 For Examples 1 to 3, non-grafted urethane rubber ( "Pandex" manufactured by Dainippon Ink Industries
T5205'') and organic solvent (MEK: methyl ethyl ketone), or for Examples 4 to 7, non-grafted urethane rubber (same as ``Pandex'')
T5205” or Bayer’s “Desmocol 450”
and graft monomer (MMA: methyl methacrylate, EA: ethyl acrylate, BMA: butyl methacrylate, 2-HEMA: 2-hydroxyethyl methacrylate, AN: acrylonitrile), organic solvent (MEK), and polymerization initiator (BPO: Chlorinated rubber and polyoxyalkylene ether polyol manufactured by Mitsui Nisso Co., Ltd. are added and dissolved in a graft rubber solution obtained by precisely weighing benzoyl peroxide (benzoyl peroxide) in a glass container and reacting for 3 hours while refluxing at 80°C. to prepare the main adhesive component (the number of copies of each component is listed in Table 1). A polyurethane adhesive is prepared by blending 20 parts of a crosslinking agent (Desmodur®) with 100 parts of the main component. Comparative Example 1 A polyurethane adhesive is prepared in the same manner as in Example 1, except that chlorinated rubber and polyoxyalkylene ether polyol are not added. Test example: PVC sheet leather product (Orsia manufactured by Sunstar Giken Co., Ltd.) and ABS resin (Kane Ace manufactured by Kanekabuchi Kagaku Co., Ltd.) made into strips of 20 mm wide x 100 mm long as an adherend. Approximately each adhesive of Examples 1 to 7 or Comparative Example 1 was applied to a resin plate.
It is coated at 100 g/m ₂ and bonded together after drying with the solvent to create an adhesive test piece. After curing and curing this test piece for one day, the autograph determined the 180° peel adhesion strength and 110° peel strength.
The peel adhesion strength is measured after aging for 3 weeks in a heated atmosphere at 110°C, and a 24-hour creep test is conducted with a load of 100 g applied to one end of the sheet in a heated atmosphere at 110°C to measure the peel length. The test results are shown in Table 2.

【table】

[Table] Comparative Example 2 A polyurethane adhesive was prepared in the same manner as in Example 1 except that no polyoxyalkylene ether polyol was added, and when it was subjected to the above test example, the 180° peel strength was 8.2 Kg/in ( AF), the peel strength after heat aging was 1.1 Kg/in (AF), and the thermal creep resistance decreased in 4 hours. Comparative Example 3 A polyurethane adhesive was prepared in the same manner as in Example except that no polyoxyalkylene ether polyol was added, and when it was subjected to the above test example, the peel strength at 180°C was 10.0 Kg/in (AF), and the adhesive was The peel strength after aging was 3.6 Kg/in (AF), and the thermal creep resistance decreased after 8 hours. From the results of Comparative Examples 2 and 3, it is recognized that in the present invention, the polyoxyalkylene ether polyol particularly contributes to improving heat aging resistance and thermal creep resistance.

Claims (1)

[Scope of Claims] 1. Thermoplastic polyester urethane rubber and/or the thermoplastic polyester urethane rubber grafted with at least one member selected from the group of acrylic acid, acrylic ester, methacrylic acid and methacrylic ester, chlorinated. A polyurethane adhesive characterized by comprising: a rubber, a polyoxyalkylene ether polyol having two or more ether groups in one molecule, and an isocyanate compound as a crosslinking agent.