JP2007023099A - One-package urethane adhesive composition for norbornene resin, elastic adhesive for norbornene resin and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-package urethane adhesive composition for norbornene resins, having excellent adhesiveness to a molded article of a norbornene resin and bondable immediately after the molding of the molded article. <P>SOLUTION: The one-package urethane adhesive composition for norbornene resins contains (A) a urethane prepolymer produced by reacting diphenylmethane diisocyanate with a polyol compound and (B) a urethane prepolymer produced by reacting a polyol compound with a compound containing an isocyanate group and having low reactivity with active hydrogen compared with diphenylmethane diisocyanate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a one-component urethane adhesive composition for norbornene-based resins, an elastic adhesive for norbornene-based resins, and a method for using the same.

In recent years, a technique for producing a norbornene-based resin molded product by reaction injection molding (hereinafter also referred to as “RIM”) using a polycyclic norbornene-based monomer typified by dicyclopentadiene has been developed. The norbornene-based resin molded product obtained by RIM has low water absorption, excellent dimensional stability, and excellent lightness and heat resistance. Therefore, for example, it is suitable for manufacturing large molded articles such as automobile housings and bodies, septic tanks, and containers (containers) for liquids. In general, in the case of such a large molded product, for example, when a septic tank is taken as an example, it is divided into an upper part and a lower part, each is molded by RIM, and these are bonded and integrated using an adhesive composition. The method to be taken is taken.
Since the adhesive composition used for such a norbornene-based resin molded product can follow the deformation of the molded product due to external stress, a urethane-based adhesive composition is used (see, for example, Patent Document 1). .)

However, norbornene resins are low in polarity and have few active sites that can be involved in adhesion. Therefore, when bonding norbornene resin molded products to each other or another adherend using an adhesive, sufficient adhesion is achieved. It was difficult to get sex.
Therefore, for the purpose of improving the adhesion to norbornene-based resin moldings, before applying an adhesive to the molding, a primer containing a high NCO% adduct body or modified body made from a monoisocyanate compound is applied. The technique which performs is known (for example, refer patent document 2).

JP-A-7-266434 JP 2003-155456 A

  However, as described above, sufficient adhesion was not obtained even when the primer composition was applied before application of the adhesive composition. Therefore, in general, the norbornene-based resin molding is allowed to stand for several days after molding, and the surface of the norbornene-based resin molding is oxidized to make it easy to adhere. It was one of the causes that took a long time to manufacture.

  Accordingly, an object of the present invention is to provide a one-component urethane adhesive composition that has excellent adhesion to norbornene-based resin moldings and can be bonded immediately after the molding is manufactured.

  As a result of intensive studies, the inventor has reacted a urethane prepolymer obtained by reacting diphenylmethane diisocyanate with a polyol compound, an isocyanate group-containing compound having a lower reactivity with active hydrogen than diphenylmethane diisocyanate, and a polyol compound. When it contains the urethane prepolymer obtained, it discovered that it became the 1 liquid urethane adhesive composition which has the adhesiveness outstanding with respect to the norbornene-type resin molding, and completed this invention.

That is, the present invention provides the following (1) to (6).
(1) a urethane prepolymer (A) obtained by reacting diphenylmethane diisocyanate and a polyol compound;
A one-component urethane adhesive composition for norbornene-based resins, comprising an isocyanate group-containing compound having a lower reactivity with active hydrogen than diphenylmethane diisocyanate and a urethane prepolymer (B) obtained by reacting a polyol compound.
(2) The one-component urethane adhesive composition for norbornene-based resin according to (1), wherein the isocyanate group-containing compound is tolylene diisocyanate or hexamethylene diisocyanate.
(3) The one-component urethane adhesive composition for norbornene-based resins according to the above (1) or (2), which is for dicyclopentadiene resins.
(4) The one-component urethane adhesive composition for norbornene-based resin according to any one of (1) to (3) above,
An elastic adhesive for norbornene-based resins comprising an isocyanate component and a primer composition containing a solvent.
(5) The elastic adhesive for norbornene-based resin according to (4), wherein the isocyanate component is tris (isocyanatephenyl) thiophosphate.
(6) A method for using the elastic adhesive for norbornene-based resin according to (4) or (5) above, wherein the primer composition is applied to the surface of the norbornene-based resin molded product; An elastic adhesive for norbornene-based resin, comprising: an adhesive application step for applying the one-component urethane adhesive composition for norbornene-based resin to the surface on which the primer composition is applied in the primer composition-application step. how to use.

  The one-component urethane adhesive composition for norbornene-based resin of the present invention has excellent adhesiveness to norbornene-based resin molded products. Therefore, it is possible to adhere without leaving the molded product for several days after the production of the molded product, and the time required for producing the molded product can be shortened.

Hereinafter, the present invention will be described in more detail.
<One-component urethane adhesive composition for norbornene-based resin>
The one-component urethane adhesive composition for norbornene-based resin of the present invention (hereinafter also referred to as “the composition of the present invention”) includes a urethane prepolymer (A) obtained by reacting diphenylmethane diisocyanate and a polyol compound. A one-component urethane adhesive composition for norbornene-based resin, comprising an isocyanate group-containing compound having a lower reactivity with active hydrogen than diphenylmethane diisocyanate and a urethane prepolymer (B) obtained by reacting a polyol compound. is there.

  The urethane prepolymer (A) used in the composition of the present invention is a urethane prepolymer obtained by reacting diphenylmethane diisocyanate (MDI) with a polyol compound.

  The polyol compound is an alcohol obtained by replacing a plurality of hydrocarbon hydrogens with a hydroxy group. Examples thereof include a product obtained by addition polymerization of at least one alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran to an active hydrogen-containing compound having two or more active hydrogens in the molecule.

Examples of the active hydrogen-containing compound having two or more active hydrogens in the molecule include polyhydric alcohols, amines, alkanolamines, and polyhydric phenols.
Specific examples of the polyhydric alcohols include ethylene glycol, propylene glycol, butanediol, diethylene glycol, glycerin, hexanetriol, trimethylolpropane, and pentaerythritol.
Examples of amines include ethylenediamine and hexamethylenediamine.
Examples of alkanolamines include ethanolamine and propanolamine.
Examples of polyhydric phenols include resorcin, bisphenols, and the like.

Specific examples of the polyol compound include polyether polyols such as polytetramethylene glycol, polyethylene glycol, polypropylene glycol, polyoxypropylene glycol, and polyoxybutylene glycol; polyolefin polyols such as polybutadiene polyol and polyisoprene polyol; adipate Preferable examples include polyester-based polyols such as lactone-based polyols; lactone-based polyols and castor oil.
These may be used alone or in combination of two or more.

  The polyol compound preferably has an average molecular weight of about 1000 to 10000, and more preferably about 2000 to 5000.

  The ratio of mixing the polyol compound and MDI in the production of the urethane prepolymer (A) is such that the ratio of the number of isocyanate groups in MDI to the number of hydroxy groups in the polyol compound (NCO / OH) is 1.0 or more. It is preferable that 1.5 to 2.5 is more preferable.

  The production of the urethane prepolymer (A) used in the composition of the present invention is carried out by mixing both compounds at a predetermined ratio in the same manner as a normal urethane prepolymer, and usually heating and stirring at 60 to 100 ° C. under normal pressure. Can be done.

  The urethane prepolymer (B) used in the composition of the present invention is a urethane prepolymer obtained by reacting an isocyanate group-containing compound having a lower reactivity with active hydrogen than MDI and a polyol compound.

The isocyanate group-containing compound used in the urethane prepolymer (B) is not particularly limited as long as the reactivity with active hydrogen is lower than the reactivity of MDI with active hydrogen (especially -OH). Specifically, for example, tolylene diisocyanate (TDI), tetramethylxylylene diisocyanate (TMXDI), trimethylhexamethylene diisocyanate (TMHMDI), 1,5-naphthalene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene Examples thereof include diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), triphenylmethane triisocyanate, diisocyanate having a norbornane skeleton (NBDI), and modified products thereof.
These may be used alone or in combination of two or more.

  Among these isocyanate group-containing compounds, 2,4-TDI is preferable. The isocyanate group at the 2-position of 2,4-TDI has very low reactivity due to steric hindrance of the methyl group. Conversely, the isocyanate group at the 4-position has no steric hindrance and is reactive because it is directly bonded to the benzene ring. Is very high. Therefore, the 4-position isocyanate group of 2,4-TDI reacts preferentially with the hydroxyl group of the polyol compound, so that the urethane prepolymer (B) having a narrow molecular weight distribution can be quickly formed. Furthermore, since the obtained urethane prepolymer (B) mainly has an isocyanate group at the 2-position having a very low reactivity at the terminal, it is difficult to inhibit adhesion between the primer composition and the adherend.

The polyol compound used for the urethane prepolymer (B) is the same as the polyol compound used for the urethane prepolymer (A).
Moreover, the manufacturing method of the said urethane prepolymer (B) is the same as the manufacturing method of a urethane prepolymer (A).

  In the composition of the present invention, the mass ratio of the urethane prepolymer (A) to the urethane prepolymer (B) is preferably 10/1 to 1/10, and more preferably 1/2 to 2/1. Within this range, the resulting composition has excellent adhesion to norbornene-based resin moldings.

By the way, norbornene-type resin has few polar groups and active hydrogen which can contribute to the adhesion | attachment which has on the surface, and adhesion | development speed with a primer is slow. Therefore, the adhesive composition containing only the relatively highly reactive MDI prepolymer reacts with the isocyanate component effective for adhesion of the primer, and even the isocyanate component of the primer that reacts with the adherend (norbornene resin). Is used for the reaction with the adhesive composition, the adhesion between the adherend and the primer is lowered.
On the other hand, an adhesive composition containing only a low-reactivity urethane prepolymer, such as a TDI prepolymer or an HDI prepolymer, hardly inhibits the adhesion between the above-described primer and the adherend, but it is very hard to cure itself. Slowly and foaming is likely to occur.
The composition of the present invention can achieve both the curability of the adhesive composition and the adhesive performance of the primer by using an MDI prepolymer and a urethane prepolymer having low reactivity, and can be used for norbornene-based resin moldings. Excellent adhesion.

The composition of the present invention can further contain a curing catalyst.
The curing catalyst is not particularly limited. Specifically, for example, tin carboxylates such as dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate, tin naphthenate, tetrabutyl titanate, tetra Titanic acid esters such as propyl titanate, organoaluminum compounds such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate, chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate And metal catalysts such as octanoic acid metal salts such as lead octoate and bismuth octoate.

  In addition, monoamines such as butylamine, octylamine, dibutylamine, triethylamine, N, N-dimethylcyclohexylamine, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'- Diamines such as tetramethylpropane-1,3-diamine, N, N, N ′, N′-tetramethylhexane-1,6-diamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine N, N, N ′, N ″, N ″ -triamines such as pentamethyldipropylenetriamine, N-methylmorpholine, N, N′-dimethylpiperazine, N-methyl-N ′-(2-dimethylamino) -Cyclic amines such as ethylpiperazine, dimethylaminoethanol, dimethylaminoethoxyethanol, N, N, N'-trimethyla Examples also include amine catalysts such as alcohol amines such as noethylethanolamine, ether amines such as bis (2-dimethylaminoethyl) ether and ethylene glycol bis (3-dimethyl) aminopropyl ether, or salts thereof. .

Among such curing catalysts, a metal catalyst containing tin in the skeleton is preferable from the viewpoint of excellent curability with a small amount.
The content of the curing catalyst is preferably 1 part by mass or less with respect to 100 parts by mass in total of the urethane prepolymers (A) and (B).

  The composition of the present invention is, as necessary, a filler, a reaction retardant, an anti-aging agent, an antioxidant, a pigment (dye), a plasticizer, and a thixotropic agent, as long as the object of the present invention is not impaired. , Ultraviolet absorbers, flame retardants, solvents, surfactants (including leveling agents), dispersants, dehydrating agents, adhesion-imparting agents, antistatic agents, and other various additives.

  Examples of the filler include organic or inorganic fillers having various shapes. Specifically, for example, fumed silica, calcined silica, precipitated silica, ground silica, fused silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; calcium carbonate, magnesium carbonate, zinc carbonate; Waxite clay, kaolin clay, calcined clay; carbon black; these fatty acid treated products, resin acid treated products, urethane compound treated products, and fatty acid ester treated products.

  Specific examples of the reaction retarder include alcohol-based compounds.

Specific examples of the anti-aging agent include hindered phenol compounds.
Specific examples of the antioxidant include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).

  Specific examples of the pigment include inorganic pigments such as titanium oxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, etc .; azo pigment, phthalocyanine pigment, quinacridone Pigment, quinacridone quinone pigment, dioxazine pigment, anthrapyrimidine pigment, anthanthrone pigment, indanthrone pigment, flavanthrone pigment, perylene pigment, perinone pigment, diketopyrrolopyrrole pigment, quinonaphthalone pigment, anthraquinone pigment, thioindigo pigment, benzimidazolone Examples thereof include organic pigments such as pigments, isoindoline pigments, and carbon black.

  Specific examples of the plasticizer include, for example, dioctyl phthalate (DOP), dibutyl phthalate (DBP); dioctyl adipate, isodecyl succinate; diethylene glycol dibenzoate, pentaerythritol ester; butyl oleate, methyl acetylricinoleate; phosphorus Examples include tricresyl acid, trioctyl phosphate; propylene glycol polyester adipate, butylene glycol polyester adipate, and the like. These may be used alone or in combination of two or more.

Specific examples of the thixotropic agent include aerosil (manufactured by Nippon Aerosil Co., Ltd.), disparon (manufactured by Enomoto Kasei Co., Ltd.), and the like.
Specific examples of the adhesion-imparting agent include terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins, and the like.

Specific examples of the flame retardant include chloroalkyl phosphate, dimethyl / methyl phosphonate, bromine / phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, brominated polyether, and the like.
Examples of the antistatic agent generally include quaternary ammonium salts; hydrophilic compounds such as polyglycols and ethylene oxide derivatives.

The production method of the composition of the present invention is not particularly limited. For example, a method in which each of the above essential components and optional components are put in a reaction vessel and sufficiently kneaded using a stirrer such as a mixing mixer under reduced pressure. Can be used.
In addition, as a method for producing the composition of the present invention, a urethane prepolymer (B) is obtained by reacting an isocyanate group-containing compound having a lower reactivity with active hydrogen than MDI and a polyol compound to obtain a urethane prepolymer (B). ) After adding MDI to the urethane prepolymer (B) obtained in the production process (first reaction) and the urethane prepolymer (B) production process, the polyol compound is added to the urethane prepolymer (A). And a urethane prepolymer (A) production process (second reaction) is preferred. With this production method, the labor for mixing the urethane prepolymers (A) and (B) can be saved, and the composition of the present invention can be produced efficiently in one reaction vessel.

  As described above, the composition of the present invention contains MDI having a relatively high reactivity as an isocyanate component in the adhesive composition and an isocyanate group-containing compound having a lower reactivity than MDI. The balance between the reaction rate for the adhesive composition and the reaction rate for the adherend is maintained. Moreover, the sclerosis | hardenability of adhesive composition itself can also be hold | maintained and foaming can be suppressed. As a result, it is thought that it has the outstanding adhesiveness with respect to a norbornene-type resin molding. Therefore, the composition of the present invention can be bonded immediately after the production of the norbornene resin molded product. Moreover, since the composition of the present invention is a one-component type that is cured by moisture, there is no need to mix the main agent and the curing agent, so that the workability is excellent.

  Since the composition of the present invention has the properties as described above, it is used as an adhesive composition (sealing material composition) for norbornene-based resins and used in combination with a primer composition for elasticity for norbornene-based resins. It is suitably used for an adhesive. As the adherend, a dicyclopentadiene resin is preferable among norbornene resins.

<Elastic adhesive for norbornene resin>
The elastic adhesive for norbornene-based resin of the present invention (hereinafter also referred to as “elastic adhesive of the present invention”) comprises the above-described composition of the present invention, a primer composition containing an isocyanate component and a solvent. It is to be prepared.

The primer composition used for the elastic adhesive of the present invention is a primer composition containing an isocyanate component and a solvent.
The isocyanate component is not particularly limited as long as it is a compound having at least two isocyanate groups at its end. Specifically, for example, 4,4′-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diene Isocyanate (XDI), hexamethylene diisocyanate (HMDI), hydrogenated (hydrogenated) MDI, hydrogenated TDI, hydrogenated XDI, isophorone diisocyanate (IPDI), aromatic aliphatic polyisocyanate, aromatic polyisocyanate, triphenylmethanetri An isocyanate, a tris (isocyanate phenyl) thiophosphate, etc. are mentioned. These may be used alone or in combination of two or more.
Among these, tris (isocyanate phenyl) thiophosphate is preferable from the viewpoint of excellent adhesion to norbornene resins. In particular, the tris (isocyanatephenyl) thiophosphate is preferably contained in an amount of 6 to 24% by mass, more preferably 10 to 20% by mass, based on the total mass of the primer. Within this range, the viscosity does not become too high and the storage stability is excellent.

The solvent used in the primer composition is not particularly limited as long as it is inert with respect to the isocyanate component, and various conventionally known solvents can be used.
Specifically, aromatic hydrocarbons such as benzene, xylene and toluene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate; diethyl ether, tetrahydrofuran and dioxane Ethers etc. are mentioned, These may be used independently and may use 2 or more types together.
The solvent is preferably used after being sufficiently dried or dehydrated. Of these, methyl ethyl ketone and ethyl acetate are preferred for reasons such as low boiling point and quick drying.

  Although content of the said solvent is not specifically limited and is suitably determined by the kind etc. of an isocyanate component, About 500-1000 mass parts is preferable with respect to 100 mass parts of isocyanate components.

In one preferred embodiment, the primer composition further contains a phosphate.
Although it does not specifically limit as a phosphate, Specifically, an aluminum phosphate, zinc phosphate, tripolyaluminum dihydrogen phosphate etc. are illustrated suitably. In particular, aluminum dihydrogen triphosphate is preferably used.

  Such phosphates may be subjected to various treatments. In particular, phosphates surface-treated with Si and / or Zn, in particular aluminum trihydrogen phosphate tri-surface treated with Si and / or Zn, can ensure extremely good adhesion. More favorable results can be obtained. Moreover, it is preferable that the phosphate has been subjected to dehydration treatment.

  As for content of the said phosphate, about 5-100 mass parts is preferable with respect to 100 mass parts of said isocyanate components. If it is this range, the effect of adding a phosphate is fully acquired, and a phosphate can fully be disperse | distributed and favorable adhesiveness can be acquired. About 30 to 60 parts by mass is more preferable because these properties are superior.

In one preferred embodiment, the primer composition further contains carbon black.
5-30 mass% is preferable and, as for content of carbon black, 5-15 mass% is more preferable. Within this range, the storage stability and the flexibility of the primer coating are excellent.

The said primer composition can contain a curing catalyst as needed.
Specific examples of the catalyst include amine catalysts such as triethylenediamine, pentamethylenediethylenetriamine, morpholine amine, and triethylamine; tin such as dilauric acid-di-n-octyltin, dibutyltin dilaurate, and stannous octoate. And system catalysts.
Although the addition amount of a curing catalyst is not specifically limited, Usually, it is about 0.1-1 mass part with respect to 100 mass parts of isocyanate components.

One of the preferable embodiments of the primer composition is a primer composition described in JP-A No. 2003-155456. Specifically, it is a primer composition containing 6 to 24% by mass of tris (isocyanatephenyl) thiophosphate, 5 to 30% by mass of carbon black, and a solvent.
The primer composition is excellent in adhesion to norbornene-based resins.

  A method for producing the primer composition is not particularly limited, and examples thereof include a method of mixing the above-described components with a roll, a kneader, an extruder, a universal stirrer, or the like.

  Examples of the primer composition include septic tank primer M (RC-50E) -J, septic tank primer M (RC-50KE) -J, and septic tank primer No. Commercial products such as 65E (both manufactured by Yokohama Rubber Co., Ltd.) may be used.

  The elastic adhesive of the present invention has excellent adhesion to norbornene-based resin molded products. Therefore, it is possible to adhere without leaving the molded product for several days after the production of the molded product, and the time required for producing the molded product can be shortened.

  The method of using the elastic adhesive for norbornene-based resin of the present invention (hereinafter referred to as “method of using the present invention”) includes a primer composition coating step of coating the primer composition on the surface of the norbornene-based resin molded product. And an adhesive application step of applying the one-component urethane adhesive composition for norbornene-based resin to the surface on which the primer composition is applied in the primer composition application step.

The primer composition application step is a step of applying the primer composition used for the above-described elastic adhesive of the present invention to the surface of the norbornene-based resin molded product.
The primer composition can be applied by a commonly employed application method such as brush coating, spray coating, wire bar method, blade method, roll coating method, dipping method and the like.

  Furthermore, it is preferable to provide the drying process which dries a primer composition after the said primer composition application | coating process. The drying method is not particularly limited, but usually, the solvent is volatilized and dried by allowing it to stand at room temperature for about 5 to 60 minutes.

The adhesive application step is a step of applying the above-described composition of the present invention to the surface on which the primer composition is applied in the primer composition application step.
The adhesive composition can be applied by using a commonly applied application method such as a brush coating method, a spray coating method, a wire bar method, a blade method, a roll coating method, or a dipping method.

After the adhesive application step, the adhesive composition applied on the primer application surface of the norbornene-based resin molded product is brought into contact with another adherend and cured, so that the norbornene-based resin molded product and the other adherend are bonded. And glue. When hardening an adhesive composition, you may heat as needed.
The counterpart adherend to be bonded to the norbornene-based resin molded product is not particularly limited, and examples thereof include resin, glass, metal and the like, and it is preferable to apply a primer composition to these adherends in advance. . In particular, in the case of a norbornene-based resin molded product, it is preferable to apply the above-described primer composition.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Synthesis of urethane prepolymer>
(MDI prepolymer)
Trifunctional polypropylene glycol (Exenol 5030, number average molecular weight of about 5000, manufactured by Asahi Glass Co., Ltd.) and bifunctional polypropylene glycol (Exenol 2020, number average molecular weight of about 2000, manufactured by Asahi Glass Co., Ltd.) in a molar ratio (Trifunctional PPG / 2-functional PPG) was mixed so as to be 2.0, and dehydrated by vacuum stirring at 100 to 110 ° C. for about 1 hour. Next, MDI (manufactured by Sumitomo Bayer Urethane Co., Ltd.), which was cooled to 60 ° C. and dissolved in advance, had a molar ratio (NCO / OH) of this isocyanate group to the hydroxy group of the polyol of 2.0. It was thrown to become. Thereafter, the mixture was stirred at 80 to 90 ° C. for 12 to 24 hours, and after confirming that the reaction was completed by measuring the NCO content, the stirring was terminated to obtain an MDI prepolymer (NCO% = 2.4). .

(TDI prepolymer)
Except having changed MDI into 2, 4-TDI (made by Sumitomo Bayer Urethane Co., Ltd.), it carried out like the synthesis method of the MDI prepolymer mentioned above, and obtained TDI prepolymer (NCO% = 2.5).

(HDI prepolymer)
Except having changed MDI into HDI (made by Sumitomo Bayer Urethane Co., Ltd.), it carried out similarly to the synthesis method of the MDI prepolymer mentioned above, and obtained HDI prepolymer (NCO% = 2.5).

(MDI / TDI prepolymer)
(1) Preparation of polyol compound Trifunctional polypropylene glycol (Exenol 5030, number average molecular weight of about 5000, manufactured by Asahi Glass Co., Ltd.) and bifunctional polypropylene glycol (Exenol 2020, number average molecular weight of about 2000, manufactured by Asahi Glass Co., Ltd.) Were mixed so that the molar ratio (trifunctional PPG / 2 functional PPG) = 2.0, and dehydrated by stirring under vacuum at 100 to 110 ° C. for about 1 hour.

(2) First reaction Next, the molar ratio of this isocyanate group and the hydroxy group of the polyol was 2,4-TDI (manufactured by Sumitomo Bayer Urethane Co., Ltd.), which was cooled to 60 ° C. and dissolved by heating in advance. (NCO / OH) was added so as to be 2.0. Then, it was made to react by stirring for 12 to 24 hours at 80-90 degreeC, and the TDI prepolymer (NCO% = 2.5) was obtained.

(3) Second reaction Next, MDI (manufactured by Sumitomo Bayer Urethane Co., Ltd.), which was heated and dissolved in advance, was added to the TDI prepolymer obtained in the first reaction and dispersed uniformly. Thereafter, the polyol compound (Excenol 5030 / Excenol 2020 = 2.0) prepared in the same manner as described above was added so that the molar ratio (NCO / OH) of the isocyanate group of MDI to the hydroxy group of the polyol was 2.0. Then, the mixture was reacted by stirring at 80 to 90 ° C. for 12 to 24 hours to obtain an MDI / TDI prepolymer (final NCO% = 2.4). The amount of MDI and polyol compound added in the second reaction was such that the mass ratio of the TDI prepolymer synthesized in the first reaction and the MDI prepolymer synthesized in the second reaction was 1/1. .

<Examples 1-3 and Comparative Examples 1-3>
Each component of the following Table 1 was mixed with the composition (parts by mass) shown in Table 1 using a stirrer to obtain each adhesive composition shown in Table 1.
About each obtained adhesive composition, adhesiveness and foamability were evaluated by the following method. The results are shown in Table 1.

<Adhesiveness>
FIG. 1 is a schematic view of a specimen used for a shear adhesion test.
A plate-shaped member 1 having a length of 100 mm (length) × 25 mm (width) × 5 mm (thickness) was cut out from a dicyclopentadiene RIM molded product for septic tank (Pentam, manufactured by Nippon Zeon Co., Ltd.) one day after molding. . An isocyanate-based primer composition (a primer composition containing tris (isocyanatephenyl) thiophosphate and ethyl acetate, trade name: M (RC-50E) -J, manufactured by Yokohama Rubber Co., Ltd.) is applied to this member 1. The primer composition was dried after taking an open time of about 5 to 10 minutes. Two of these were prepared.

  Next, the obtained adhesive composition is applied onto the primer application surface of the member 1 so that the adhesion area is 25 mm × 25 mm, and the other member 1 is interposed through the spacer 3 having a thickness of 1 mm. The primer composition-coated surface and the adhesive 5 were brought into contact with each other so as to have a thickness of about 1 mm, and were cured at 20 ° C. and 60% RH for 7 days to prepare test specimens.

Using the prepared specimen, the shear bond strength was measured at a pulling speed of 5.0 mm / min.
In addition, by visually observing the destruction state, “CF” indicates that the adhesive is agglomerated and fractured, “AF” indicates that the interface peels between the adherend and the primer composition, and part of the adhesive is An uncured and partially cohesive failure was defined as “uncured CF”.

<Foaming properties>
The foaming state of the adhesive of the test body used in the shear adhesion test was visually observed. Those with no voids were marked with “◯”, and those with voids were marked with “x”.

Each component shown in Table 1 is as follows.
・ Plasticizer: Dioctyl phthalate ・ Carbon black: Asahi Thermal Carbon, manufactured by Asahi Carbon ・ Calcium carbonate: Super # 1500, manufactured by Maruo Calcium ・ Curing catalyst: Dibutyltin laurate

  As is apparent from the results shown in Table 1, the adhesive compositions of Examples 1 to 3 have extremely excellent adhesiveness compared to the adhesive compositions of Comparative Examples 1 to 3, and foamed. Also did not occur.

FIG. 1 is a schematic view of a specimen used for a shear adhesion test.

Explanation of symbols

1 Member 3 Spacer 5 Adhesive

Claims (6)

A urethane prepolymer (A) obtained by reacting diphenylmethane diisocyanate and a polyol compound;
A one-component urethane adhesive composition for norbornene-based resins, comprising an isocyanate group-containing compound having a lower reactivity with active hydrogen than diphenylmethane diisocyanate and a urethane prepolymer (B) obtained by reacting a polyol compound.   The one-component urethane adhesive composition for norbornene-based resin according to claim 1, wherein the isocyanate group-containing compound is tolylene diisocyanate or hexamethylene diisocyanate.   The one-pack type urethane adhesive composition for norbornene-based resin according to claim 1 or 2, which is for dicyclopentadiene resin. One-component urethane adhesive composition for norbornene-based resin according to any one of claims 1 to 3,
An elastic adhesive for norbornene-based resins comprising an isocyanate component and a primer composition containing a solvent.   The elastic adhesive for norbornene-based resin according to claim 4, wherein the isocyanate component is tris (isocyanate phenyl) thiophosphate.   A method of using the elastic adhesive for norbornene-based resin according to claim 4 or 5, wherein the primer composition is applied to the surface of a norbornene-based resin molding, and the primer composition is applied. A method of using an elastic adhesive for norbornene-based resin, comprising: an adhesive application step of applying the one-component urethane adhesive composition for norbornene-based resin to the surface on which the primer composition is applied in the step.

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