JPH05222342A - Primer resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent initial tack and markedly improved water-resistant adhesion. CONSTITUTION:The title composition comprises an isocyanate-containing silane compound prepared by reacting an organic polyisocyanate with an aminosilane compound and/or a mercaptosilane compound in an equivalent ratio of the isocyanate groups to the amino groups and/or the mercapto groups of 1/0.20-1/0.95. When a urethane elastomer excellent in abrasion resistance, corrosion resistance and water resistance is used in a state bonded to a metal, a plastic or the like, it is excellent in initial tack and water-resistant adhesion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to wear resistance, corrosion resistance,
Regarding a resin composition for a primer suitable for adhesion of a urethane elastomer having excellent water resistance, specifically, after applying a primer containing polyvinyl butyral as a main component as a primary primer to a surface of an adherend such as a metal, if necessary, and drying it Prior to obtaining a molded article by injecting or spray-coating a two-part curable polyurethane elastomer stock solution onto it and curing it, an isocyanate group-containing silane compound is used as a primer on the primary primer or directly on the surface of an adherend. The present invention relates to a primer resin composition comprising coating and drying the primer resin composition containing the primer resin composition, which is particularly excellent in water-resistant adhesion between a urethane elastomer and an adherend.

[0002]

2. Description of the Related Art Urethane elastomers are used in various industrial materials such as rolls, belts and solid tires because they have excellent mechanical properties, abrasion resistance and chemical resistance.

At this time, depending on the application of the urethane elastomer, it is often necessary to adhere it to a metal or a plastic such as ABS or nylon. For example, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA).
When a heat-curable urethane elastomer that is cured with an amine compound represented by
A phenol resin-based primer such as emlok218 or Conap1146C (both are trade names) or another epoxy resin-based primer is used. However, in this case, even if the initial adhesive strength is sufficient, the adhesive strength is greatly reduced and satisfactory water resistance can be obtained in applications where it is immersed in warm water for a long period of time, or particularly when it is used in an environment of hot water immersion with a temperature gradient. I can't.

When the above-mentioned phenol resin-based or epoxy resin-based primer is used, good adhesion cannot be obtained at a heating temperature lower than 100 ° C. Therefore, 3,3 '
-Dichloro-4,4'-diaminodiphenylmethane (M
There are many problems in terms of work when a heat-curable urethane elastomer that is cured with an amine compound represented by OCA) is adhered to a metal, and when a polyol-curable urethane elastomer that is cured at a lower temperature is adhered to a metal.

[0005]

Therefore, as a countermeasure, various double-coated primers have been proposed up to now. For example, there is disclosed a method in which an epoxy-based primer is applied to the surface of an adherend such as a metal, then a urethane-based or epoxy-urethane-based primer is applied, and a urethane elastomer stock solution is poured onto and adhered to the primer. 57-184475, JP-A-58-20163.
No. 8, JP-A No. 62-4477).

However, all of the above-mentioned techniques have the drawback that the initial adhesive strength is slow to develop, which is not preferable in practice.

[0007]

[Means for Solving the Problems] When the urethane elastomer is bonded to a metal or a plastic such as ABS or nylon, the inventors of the present invention have excellent initial adhesiveness, firmly adhered, and excellent water-resistant adhesiveness. As a result of earnest research on a resin composition for a primer suitable for obtaining a bonded adhesive,
If necessary, a primer containing polyvinyl butyral as a main component is applied to the surface of an adherend such as a metal as a primary primer and dried, and then the primary primer is injected or sprayed with a two-part curable polyurethane elastomer stock solution to cure the primer. By applying a primer resin composition containing an isocyanate group-containing silane compound as a primer on or directly to the surface of an adherend and drying it, initial adhesiveness is significantly improved, and a product having excellent water-resistant adhesiveness is obtained. The present invention has been completed and the present invention has been completed.

[0008]

That is, the present invention comprises an organic polyisocyanate and an aminosilane compound and / or a mercaptosilane compound, preferably an equivalent ratio of isocyanate groups to amino groups and / or mercapto groups of 1 / 0.20 to 1 / 0.95.
A resin composition for a primer, which comprises a silane compound containing an isocyanate group reacted with.

As the organic polyisocyanate, hexamethylene diisocyanate, lysine diisocyanate,
Isophorone diisocyanate, xylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4-tolylene diisocyanate,
2,6-Tolylene diisocyanate, 4,4'-Diphenylmethane diisocyanate, p-Phenylene diisocyanate, m-Phenylene diisocyanate, 1,5-
Examples thereof include naphthylene diisocyanate, triphenylmethane triisocyanate, and mixtures and modified products thereof.

As the aminosilane compound, an aminosilane compound having at least one amino group which is a functional group active with respect to an isocyanate group in the molecule can be used. For example, γ-aminopropyltrimethoxysilane and γ-amino. Propyltriethoxysilane, aminomethyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, N- (β-aminoethyl) aminomethyltrimethoxysilane, γ-aminoisobutyltrimethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, N- (β-amino Ethyl) -γ-aminopropylmethyldimethoxy Run, N-(beta-aminoethyl)-.gamma.-amino -β- methyl trimethoxy silane, N-(alpha-carboxymethyl-aminoethyl)
Mention may be made of -γ-aminopropyltrimethoxysilane and one or a mixture of two or more of these analogues.

As the mercaptosilane compound, a mercaptosilane compound having at least one mercapto group which is a functional group active for an isocyanate group in the molecule can be used. For example, γ-mercaptopropyltrimethoxysilane, γ -Mercaptopropyltriethoxysilane, mercaptomethyltriethoxysilane,
γ-mercaptopropylmethyldiethoxysilane, γ-
Mention may be made of mercaptoisobutyltrimethoxysilane and one or a mixture of two or more of these analogues.

An isocyanate group-containing silane compound can be obtained by reacting an organic polyisocyanate with an aminosilane compound and / or a mercaptosilane compound, and any of these reactions can be carried out in a solvent or without a solvent.

The organic polyisocyanate and the aminosilane compound and / or the mercaptosilane compound are preferably reacted at an equivalent ratio of the isocyanate group to the amino group and / or the mercapto group of 1 / 0.20 to 1 / 0.95. When the equivalent ratio is 1 / 0.20 or more, the effect of using the isocyanate group-containing silane compound is not sufficient,
When the equivalence ratio is 1 / 0.95 or less, unreacted aminosilane compound and / or mercaptosilane compound remain and there is a problem in compatibility.

By using this isocyanate group-containing silane compound in combination with a urethane prepolymer having a terminal isocyanate group, a resin composition more suitable for a primer can be obtained. At this time, the isocyanate group-containing silane compound is preferably contained in an amount of 1 to 50% by weight based on the total amount of the polyurethane-based primer. If it is 1% by weight or less, no effect is obtained, and if it is 50% by weight or more, there is a problem in coating strength of the secondary primer.

The urethane prepolymer having a terminal isocyanate group is obtained by reacting the above-mentioned organic polyisocyanate alone or in combination of two or more with polyols, and the urethane prepolymer is generally an unreacted organic compound. Contains polyisocyanate.

The polyols used herein preferably have linear terminal hydroxyl groups and preferably have a molecular weight of 500 to 6,0.
The diols of 00 may be used alone or in combination of two or more. Moreover, you may use together polyhydric alcohol.

Molecular weight of 500-having linear terminal hydroxyl groups
Examples of the 6,000 diol include polyester polyol and polyether polyol. Examples of the polyester polyol include a polyester polyol obtained by polycondensing a polyhydric alcohol and a polybasic carboxylic acid or a hydroxycarboxylic acid,
Furthermore, polycaprolactone diols obtained by ring-opening addition polymerization of a lactone such as ε-caprolactone in the presence of glycol and the like can be mentioned.

Examples of the polyhydric alcohol mentioned here include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,3-butylene glycol, 1,4-butylene glycol and 2,2'-.
Dimethyl 1,3-propanediol, diethylene glycol, 1,5-pentamethylene glycol, 1,6-hexamethylene glycol, cyclohexane 1,4-diol, cyclohexane 1,4-dimethanol, etc., alone or in combination of two or more. Can be used. Examples of polybasic carboxylic acids include succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid. The acid or the like can be used alone or in combination of two or more kinds. Also useful are castor oil, which is a condensate of polyhydric alcohol and hydroxycarboxylic acid, or a reaction product of castor oil and ethylene glycol, propylene glycol, or the like.

As the polyether polyol, for example, a product obtained by addition-polymerizing one kind or two kinds or more of alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide to a compound having two or more active hydrogens, or tetrahydrofuran is used. Examples thereof include polytetramethylene glycol obtained by ring-opening polymerization. In this case, the compound having two or more active hydrogens includes, for example, the above-mentioned polyhydric alcohols and polybasic carboxylic acids, amines such as ethylenediamine, hexamethylenediamine, diethyltoluenediamine, ethanolamine and propanolamine. And alkanolamines, polyphenols such as resorcin, bisphenol, castor oil and the like.

By reacting an organic polyisocyanate and a polyol with an equivalence ratio of isocyanate group and hydroxyl group of preferably 1 / 0.20 to 1 / 0.95, a urethane prepolymer having a terminal isocyanate group is obtained. Although obtained, any of these reactions can be carried out in a solvent or without a solvent.

As the solvent suitable for the present invention, a solvent inert to an isocyanate group is used. Examples of the solvent include toluene, xylene, methyl ethyl ketone, methylene chloride, cellosolve acetate, methyl isobutyl ketone, ethyl acetate, butyl acetate and the like.

The resin composition for a primer of the present invention can of course be used alone, but particularly in the case of adhesion to a metal, as a primary primer on the metal surface before using the resin composition for a primer of the present invention. By using a primer whose main component is polyvinyl butyral, better adhesiveness can be obtained.

The polyvinyl butyral used as the primary primer is obtained by reacting polyvinyl alcohol obtained by saponifying polyvinyl acetate with butyraldehyde under an acid catalyst. If necessary, basic zinc chromate, phosphoric acid, alcohols, etc. are added to form a primer. For this, a commercially available product generally defined as JIS-K-5633 and generally called an etching primer or a wash primer can be used.

The two-component curing type polyurethane elastomer used in the present invention is the above-mentioned 3,3'-dichloro-4,4'-.
Examples thereof include a heat-curable (amine-curable) urethane elastomer and a polyol-curable urethane elastomer that are cured with an amine compound represented by diaminodiphenylmethane (MOCA).

The amine-curable urethane elastomer is usually prepared by reacting the above-mentioned polyols and the above-mentioned organic polyisocyanate with an isocyanate group-containing prepolymer and an amine compound at 80 ° C. and 11 ° C., respectively.
It is obtained by heating to about 0 ° C., mixing and curing. The polyol-curable urethane elastomer is usually
A prepolymer similar to that of the amine-curing type and a mixed solution containing a polyol, a chain extender such as a polyhydric alcohol, and a urethanization catalyst are generally used at a temperature lower than that of the amine-curing type (for example, 50 to 50% each). It is obtained by mixing and curing at 80 ° C.

Examples of the adherend to which the urethane elastomer is adhered include metals such as iron, stainless steel, aluminum and magnesium, and, as described above, AB
Examples thereof include plastics such as S, nylon, vinyl chloride and polycarbonate, natural rubber and urethane elastomer.

The primer resin composition of the present invention is generally used as follows. First, the surface of the adherend is cleaned by degreasing or the like, and then, if necessary, a primary primer containing polyvinyl butyral as a main component is applied and dried to form a primary primer layer. At this time, the primary primer is applied so that the thickness after drying is 5 to 300 μ, and preferably 20 to 200 μ. Next, on the primary primer layer,
Alternatively, the primer resin composition of the present invention is directly applied to the surface of an adherend and dried to form a primer layer. Also at this time,
The thickness of the resin composition for a primer of the present invention after drying is 5 to 5
It is applied so as to have a thickness of 300 μ, preferably 20 to 200 μ. Each of these primer layers is formed by applying a primer by brush coating, flow coating, spraying or the like. All of these are usually left to stand for 2 to 3 hours at room temperature until the solvent is scattered, but in order to sufficiently remove the solvent, it is preferable to heat the adherend of the base to about 40 to 80 ° C. Then, a urethane elastomer stock solution prepared by mixing the two solutions is injected or sprayed onto the surface of the primer layer to cure the solution. In this case, the urethane elastomer stock solution may be applied by dipping, brushing or the like depending on the shape of the base.

[0028]

EXAMPLES The present invention will now be described by way of examples, but this is only one mode and the present invention is not limited to the examples.

All "parts" and "%" in the text are based on weight. [Synthesis Example] [Synthesis of UT-M1] 1000 g of polytetramethylene glycol having a molecular weight of 1000 and 1,4 butanediol 1
80 g and 270 g of trimethylolpropane were dissolved in 4000 g of toluene, and 1650 g of an 80/20 mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate was added under a nitrogen stream and reacted at 80 ° C. for 5 hours. A urethane prepolymer having a terminal isocyanate group was obtained.

Next, 750 g of 4,4'-diphenylmethane diisocyanate and 600 g of γ-mercaptopropyltrimethoxysilane were reacted at an equivalence ratio of 1 / 0.51 under a nitrogen stream in 1000 g of toluene at 80 ° C. for 5 hours to react with isocyanate. The total amount of the polyurethane-based primer containing 30% by weight of the group-containing silane compound (excluding the solvent content) is added to the above-mentioned urethane prepolymer, and UT is added.
-M1.

[Synthesis of UM-A1] 1000 g of polytetramethylene glycol having a molecular weight of 1000, 180 g of 1,3 butanediol, and trimethylolpropane 400
g and toluene 4000 g and methyl ethyl ketone 100
It was dissolved in 0 g of a mixed solvent, and 3000 g of 4,4′-diphenylmethane diisocyanate was added under a nitrogen stream,
A urethane prepolymer having a terminal isocyanate group was obtained by reacting at 3 ° C for 3 hours.

Next, 1000 g of 4,4'-diphenylmethane diisocyanate and 1200 g of γ-aminopropyltrimethoxysilane were reacted at an equivalence ratio of 1 / 0.84 under a nitrogen stream in 2000 g of toluene at 80 ° C. for 5 hours to react with isocyanate. The total amount of the polyurethane-based primer containing 32% by weight of the group-containing silane compound (excluding the solvent content) was added to the above-mentioned urethane prepolymer, and UM
-It was set to A1.

[Synthesis of Epoxy Primer (Comparative Example)] Epicoat 1001 (manufactured by Yuka Shell Co., bisphenol A type epoxy resin, epoxy equivalent 450-50)
0, trade name) 300 g and Epicoat 152 (Petrol Novolak type epoxy resin manufactured by Yuka Shell Co., epoxy equivalent 172 to 179, trade name) 140 g were dissolved in 150 g of toluene to be used as the main component of the epoxy primer.

270 g of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Inc.) and Epicoat 828 (manufactured by Yuka Shell Co., bisphenol A type epoxy resin, epoxy equivalent 184-
194, trade name) 60 g under nitrogen flow at 90 ° C. for 5 hours, and after allowing to cool, 290 g of toluene, 90 g of ethyl cellosolve and 170 g of methyl ethyl ketone are added to form a uniform solution, and used as a curing agent for the epoxy primer. did.

The main agent and the curing agent were mixed at a ratio of 3/1 (weight ratio) and used as a primer. [Synthesis Example of Urethane Elastomer Stock Solution] [Synthesis of PR-1] 1000 g of polytetramethylene glycol having a molecular weight of 2000 and 750 g of 4,4′-diphenylmethane diisocyanate were mixed at 80 ° C. under a nitrogen stream at 3 ° C. for 3 days.
The reaction was carried out for a time to obtain a urethane prepolymer PR-1 containing an isocyanate terminal group.

[Synthesis of GR-1] 1000 g of polytetramethylene glycol having a molecular weight of 1000, 400 g of 1,4 butanediol, a urethane-forming catalyst and 0.14 g of dibutyltin dilaurate were uniformly mixed to prepare GR-1.

[Primer coating method] The resin composition for a primer of the present invention was applied to a 70 × 150 × 3.2 mm adherend test piece degreased with toluene, and the film thickness after drying was about 30 μm.
And was dried in an oven at 60 ° C. for 30 minutes.

When a primer containing polyvinyl butyral as a main component is applied as the primary primer before forming the primer layer of the present invention, the dry film thickness is about 30 in the same manner.
After being coated so as to have a thickness of μ, it was dried at 60 ° C. for 30 minutes.

The urethane elastomer was injected on the same day as the application of the primer. [Urethane Elastomer Injection Method] [PR-1 / GR-1] Urethane elastomer stock solution, 200 g of PR-1 and 70 g of GR-1 were degassed at 80 ° C. under a reduced pressure of 20 mmHg for about 20 minutes. After that, the mixture is stirred and mixed for about 30 seconds with a stirrer so as not to entrain air, and the resulting mixture is poured onto the surface of the adherend coated with the primer to a thickness of about 2 mm and cured, and the mixture is allowed to stand at 23 ° C., 60 ° C. While standing at% RH (relative humidity), the normal-state adhesive strength was measured 5 minutes, 15 minutes, 60 minutes, 1 day, and 7 days after injection.

[In the case of PANDEX4030 / MOCA] Urethane elastomer stock solution, PANDEX4030
(Urethane prepolymer for two-component curing type polyurethane elastomer) and curing agent 3,3'-dichloro-
4,4'-diaminodiphenylmethane (MOCA) 24
g and 80 g at 80 ° C. and 110 ° C. under a reduced pressure of 20 mmHg for about 20 minutes, and then mixed by stirring for about 30 seconds so that air is not entrained in the stirrer, and the resulting mixed solution is applied to an adherend coated with a primer. It was poured onto the surface so as to have a thickness of about 2 mm, cured, and primary-aged at 110 ° C. for 50 minutes. Then, it was once taken out from the aging furnace, and the adhesive strength was measured 60 minutes after the injection. Other specimens prepared at the same time were second-aged at 110 ° C for 5 hours, then at 23 ° C, 60% R.
1 day and 7 days after injection while standing at H (relative humidity)
The normal state adhesive strength after day was measured.

[Measurement Method of Adhesive Strength] A notch having a width of 1 inch is made parallel to the surface of the adherend at the center of the longitudinal direction of the test piece, one end is peeled off, a grip portion is formed, and an angle of 90 degrees is 50 mm / The peel strength was measured at a speed of min.

[Measurement Method of Water-Resistant Adhesive Strength] After making the above-mentioned notch, it was immersed in warm water of 70 ° C. and left at a uniform temperature for a predetermined number of days, and then the 90-degree peel strength was measured by the above-mentioned method.

[Examples 1-9, Comparative Examples 1-9]

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

[Table 8] In Tables 1, 3, 5, and 7, as pre-made primers, polyvinyl butyral-based primers Vinylex [Shinto Paint Co., Ltd.] and Shinto Wash [Shinto Paint Co., Ltd.]
Made], Phenolic resin primer Chemlock 218
(Made by LORD FAR EAST INC.) Was used.

From the test results shown in Table 2, Table 4, Table 6 and Table 8, all of the resin compositions for a primer of the present invention showed high normal adhesive strength and were immersed in hot water at 70 ° C. for 7 days. Almost no decrease in adhesive strength is observed even after that. Further, in the case of the polyol-curable urethane elastomer, the initial adhesive strength was also evaluated, and all showed high strength.

[0053]

Industrial Applicability The resin composition for a primer of the present invention, when used by adhering a urethane elastomer having excellent wear resistance, corrosion resistance and water resistance to a metal or plastics,
Excellent initial adhesion and water resistant adhesion.

Claims (4)

[Claims] 1. A resin composition for a primer, comprising an isocyanate group-containing silane compound obtained by reacting an organic polyisocyanate with an aminosilane compound and / or a mercaptosilane compound. 2. The isocyanate group-containing silane compound is obtained by reacting an isocyanate group with an amino group and / or a mercapto group at an equivalent ratio of 1 / 0.20 to 1 / 0.95. 1. The resin composition for a primer according to 1. 3. A resin composition for a primer, comprising the above-mentioned isocyanate group-containing silane compound and a urethane prepolymer having a terminal isocyanate group. 4. The primer resin composition according to claim 1, wherein the primer resin composition contains an isocyanate group-containing silane compound in an amount of 1 to 50% by weight.