JP2012251053A - Urethane resin adhesive composition - Google Patents

Abstract

The present invention provides a urethane resin adhesive composition that solidifies in a short time by heating, has high strength and high elongation, and is excellent in adhesiveness.
A urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates, 2-methyl-1,4-diazabicyclo [2,2,2] octane, and 1,5-diazabicyclo. [4,3,0] nonene-5 or a salt thereof and 1,8-diazabicyclo [5,4,0] undecene-7 or a salt thereof, and the polyfunctional polyol includes: A first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less and a second polyfunctional polyol having a number average molecular weight of 1,000 or more and 4000 or less, wherein the first polyfunctional polyol and the second polyfunctional polyol are: The average OH value is 150 or more and 800 or less, and the content of the first polyfunctional polyol is 5% by mass or more and 50% by mass or less with respect to the sum of all polyfunctional polyols. The functional isocyanate is a urethane resin adhesive composition having an NCO / OH ratio of 0.8 or more and 1.2 or less.
[Selection figure] None

Description

  The present invention relates to a urethane resin adhesive composition having high strength, high elongation and excellent adhesion.

  With the reduction in weight of automobile bodies such as automobiles, there is an increasing demand in the market for adhesives that enable joining of dissimilar materials, such as joining of aluminum and resin, from joining of iron by conventional welding methods.

  For example, an adhesive of an epoxy resin composition that can be used as an adhesive for a structural member such as an automobile and has a low deterioration in adhesive properties even when a large load is applied for a long time has been proposed (for example, a patent) Reference 1). Further, as a direct glazing material used for bonding an automobile body and a window glass, an adhesive of a one-part moisture curable urethane composition has been proposed (for example, see Patent Document 2).

JP 2006-514144 A JP 2006-176664 A

  However, since the adhesive described in Patent Document 1 is an epoxy resin composition and has high strength but low elongation (elongation), there is a problem that an adhesive having extensibility like a direct glazing material cannot be obtained. .

  Moreover, since the adhesive described in Patent Document 2 is a direct glazing material and has high elongation but low strength, there is a problem that an adhesive having high strength cannot be obtained as compared with an epoxy resin composition.

  Therefore, there is a demand for an adhesive composition that satisfies the properties of high strength and high elongation and excellent adhesion.

  The present invention has been made in view of the above, and an object thereof is to provide a urethane resin adhesive composition that is solidified in a short time by heating, has high strength and high elongation, and is excellent in adhesiveness. .

  That is, the present invention is (1) shown below.

  (1) A urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates, 2-methyl-1,4-diazabicyclo [2,2,2] octane, and 1,5-diazabicyclo [ 4,3,0] nonene-5 or a salt thereof and 1,8-diazabicyclo [5,4,0] undecene-7 or a salt thereof, and the polyfunctional polyol is a number of A first polyfunctional polyol having an average molecular weight of 50 or more and 800 or less and a second polyfunctional polyol having a number average molecular weight of 1,000 or more and 4000 or less, wherein the first polyfunctional polyol and the second polyfunctional polyol are: The average OH value is 150 or more and 800 or less, and the content of the first polyfunctional polyol is 5% by mass or more and 50% by mass or less with respect to the sum of all polyfunctional polyols. The urethane resin adhesive composition, wherein the socyanate has an NCO / OH ratio of 0.8 or more and 1.2 or less.

  According to the present invention, it is possible to obtain a urethane resin adhesive composition that is solidified in a short time by heating, has high strength and high elongation, and is excellent in adhesiveness.

  Hereinafter, the present invention will be described in detail. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  The urethane resin adhesive composition according to this embodiment will be described. The urethane resin adhesive composition of the present embodiment includes a urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates, and 2-methyl-1,4-diazabicyclo [2,2,2]. Octane (Me-DABCO), 1,5-diazabicyclo [4,3,0] nonene-5 (DBN) or a salt thereof, and 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) or Any one of the salts thereof, and the polyfunctional polyol includes a first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less and a second polyfunctional polyol having a number average molecular weight of 1,000 or more and 4000 or less. The first polyfunctional polyol and the second polyfunctional polyol have an average OH number of 150 or more and 800 or less, and the content of the first polyfunctional polyol is all the polyfunctional polyols. The polyfunctional isocyanate is a urethane resin adhesive composition having an NCO / OH ratio of 0.8 to 1.2. Hereinafter, the urethane resin adhesive composition of this embodiment may be referred to as “the adhesive composition of this embodiment”. Below, the component contained in the urethane resin adhesive composition of this embodiment is demonstrated.

  Here, in the present embodiment, the “structural adhesive” means a highly reliable adhesive (JIS K6800) with little deterioration in adhesive properties even when a large load is applied for a long time.

<Urethane resin>
The urethane resin contained in the urethane resin adhesive composition of the present embodiment is not particularly limited, and a known urethane prepolymer having a plurality of isocyanate group terminals in the molecule can be used. The urethane prepolymer is preferably liquid at room temperature from the viewpoint of handling. The urethane prepolymer is a reaction product obtained by reacting a polyol compound and a polyisocyanate compound such that an isocyanate group (NCO group) is excessive with respect to a hydroxy group (OH group), It is a polymer containing an isocyanate group at the molecular end. The urethane prepolymer preferably contains 0.5% by mass or more and 5% by mass or less of isocyanate groups at the molecular ends. This isocyanate group may be bonded to either an aromatic hydrocarbon or an aliphatic hydrocarbon.

(Polyfunctional polyol)
The urethane resin adhesive composition of the present embodiment includes two or more bifunctional or more polyfunctional polyols having different number average molecular weights. The polyfunctional polyol (polyol compound) contained in the urethane resin adhesive composition of the present embodiment includes a first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less and a second polyfunctional polyol having a number average molecular weight of 1,000 or more and 4000 or less. The first polyfunctional polyol and the second polyfunctional polyol have an average OH number of 150 or more and 800 or less.

  In such a polyfunctional polyol, the content of the first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less is preferably 5% by mass or more and 50% by mass or less based on the sum of all polyfunctional polyols. .

  Hereinafter, the polyfunctional polyol of this embodiment is referred to as “polyol compound”.

  The polyol compound is not particularly limited, and may be, for example, any of polyether polyol, polyester polyol, acrylic polyol, polycarbonate polyol, and other polyols. These polyols may be used alone or in combination. Specific examples of the polyol compound include polypropylene ether diol, polyethylene ether diol, polytetramethylene glycol, polyethylene glycol, polypropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxypropylene triol, polyoxybutylene glycol, polytetraethylene. Methylene ether glycol, polymer polyol, poly (ethylene adipate), poly (diethylene adipate), poly (propylene adipate), poly (tetramethylene adipate), poly (hexamethylene adipate), poly (neopentylene adipate), poly-ε -Caprolactone, poly (hexamethylene carbonate), silicone polyols and the like. A natural polyol compound such as castor oil may be used.

  In addition, the first polyol compound is preferably a polyether polyol having a number average molecular weight of 50 or more and 1000 or less because the viscosity of the composition and the physical properties of the cured product of the composition are excellent. A polyether polyol of 50 or more and 900 or less is more preferable, and a polyether polyol having a number average molecular weight of 50 or more and 800 or less is more preferable. The content of the first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less is 5% by mass or more and 50% by mass or less with respect to the sum of all the polyfunctional polyols of the adhesive composition of the present embodiment. Is preferred.

  The second polyol compound is preferably a polyether polyol having one or more number average molecular weights of 1000 or more and 15000 or less, more preferably a polyether polyol having a number average molecular weight of 1000 or more and 10,000 or less, and a number average molecular weight of 1000 or more. More preferred is a polyether polyol of 4000 or less.

  In the present embodiment, the number average molecular weight is measured by a gel permeation chromatography (GPC).

(Polyfunctional isocyanate)
The urethane resin adhesive composition of the present embodiment includes a polyfunctional isocyanate (isocyanate compound) having two or more functions. The polyfunctional isocyanate contained in the urethane resin adhesive composition of this embodiment is a polyisocyanate having two or more isocyanate groups. By containing such a polyfunctional isocyanate, the urethane resin adhesive composition of the present embodiment has high strength, high elongation, and excellent adhesiveness. Moreover, as for the compounding quantity of the polyfunctional isocyanate contained in the urethane resin adhesive composition of this embodiment, NCO / OH ratio is 0.8 or more and 1.2 or less. Hereinafter, the polyfunctional isocyanate of this embodiment is referred to as “polyisocyanate compound”.

The polyisocyanate compound used for synthesizing the urethane resin adhesive composition used in the present embodiment is used in the production of a urethane-based prepolymer, and particularly if it has two or more isocyanate groups in the molecule. It is not limited. Examples of the polyisocyanate compound include an aromatic polyisocyanate in which an isocyanate group is bonded to an aromatic hydrocarbon, an aliphatic polyisocyanate in which an isocyanate group is bonded to an aliphatic hydrocarbon, and an isocyanate group having an alicyclic hydrocarbon. And an alicyclic polyisocyanate bonded to the. Examples of the aromatic polyisocyanate include toluene such as TDI (for example, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), or a mixture thereof. Diisocyanate), MDI (e.g., diphenylmethane diisocyanate such as 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), or mixtures thereof), 1 , 4-phenylene diisocyanate, diphenyl diisocyanate, polymethylene polyphenylene polyisocyanate, tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), diphenyl ether diisocyanate, triphenyl mesocyanate Such as emissions triisocyanate, and the like. Aliphatic polyisocyanates include propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), tetramethyl. And xylylene diisocyanate (TMXDI). Examples of the alicyclic polyisocyanate include cyclohexane diisocyanate, methylene bis (cyclohexyl isocyanate), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis (isocyanate methyl) cyclohexane (H ₆ XDI), dicyclohexylmethane diisocyanate (H ₁₂ MDI). These aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanate carbodiimide-modified polyisocyanates, biuret-modified polyisocyanates, allophanate-modified polyisocyanates, polymethylene polyphenyl polyisocyanates (crude MDI or polymeric MDI), isocyanurates Examples thereof include modified polyisocyanates.

  Such polyisocyanate compounds can be used alone or in combination of two or more. Among these polyisocyanate compounds, TDI and MDI are preferred among the aromatic polyisocyanates, and among the aliphatic polyisocyanates, the viscosity becomes low after curing and the handling of the main agent containing the urethane-based prepolymer is easy. Among HDI, XDI and alicyclic polyisocyanate, IPDI is preferred. As the polyisocyanate compound, 4,4′-diphenylmethane diisocyanate is preferable because it is easily available and inexpensive.

  The combination of the polyol compound and the polyisocyanate compound is not particularly limited, and each of the polyol compound and each of the polyisocyanate compound can be arbitrarily combined. For example, a urethane prepolymer obtained from polypropylene glycol and MDI is preferable from the viewpoint of physical property adjustment, cost, and availability.

  The mixing ratio of the polyol compound and the polyisocyanate compound is such that the molar ratio of the isocyanate (NCO) group in the polyisocyanate compound to the hydroxy (OH) group in the polyol compound (NCO / OH ratio) is 0.8 or more and 1.2 or less. It is preferable that it is 0.9 or more and 1.1 or less. In such a range, the viscosity of the urethane prepolymer is moderate and the elongation of the cured product is excellent.

  The reaction between the polyol compound and the polyisocyanate compound is not particularly limited. For example, the polyol compound and the polyisocyanate compound having the above-mentioned quantitative ratio are 30 ° C. or higher and 120 ° C. or lower, preferably 50 ° C. or higher and 100 ° C. or lower. The method of manufacturing by heating and stirring with is mentioned.

  The polyurethane resin as the reaction product is preferable because of excellent initial adhesiveness. The polyurethane resin is obtained by copolymerizing monomers with a urethane bond formed by condensation of an isocyanate group and an alcohol group, and is not particularly limited as long as the number average molecular weight is 15,000 or more.

<Catalyst>
As the catalyst contained in the urethane resin adhesive composition of the present embodiment, a temperature-sensitive catalyst having a larger activity at the time of heating than usual can be used, such as a resinification reaction between a polyol compound and a polyisocyanate compound, etc. The catalyst function can be exhibited depending on temperature conditions. In particular, a temperature-sensitive catalyst capable of exhibiting a catalytic function when heated to a predetermined temperature of 20 ° C. or more and 90 ° C. or less is preferably used, and the following amine catalysts are preferably exemplified. Specifically, 2-methyl-1,4-diazabicyclo [2,2,2] octane (Me-DABCO) represented by the following formula (1), 1,5-represented by the following formula (2) Amidino groups [H ₂ such as diazabicyclo [4,3,0] nonene-5 (DBN) and 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) represented by the following formula (4) In addition to diazabicycloalkene having NC (= NH)-] or a salt thereof, triethylenediamine, a mixture of triethylenediamine and polypropylene glycol, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methyl Examples include imidazoles such as imidazole. Of these, diazabicycloalkene having high catalytic activity or a salt thereof such as phenol salt or octylate is preferred as the temperature-sensitive catalyst. The DBN salt is represented by the following general formula (3), and the DBU salt is represented by the following general formula (5).

（上記一般式（３）中、Ｘは無機または有機の酸残基を表す）

(In the general formula (3), X represents an inorganic or organic acid residue)

  In the general formula (3), X represents an inorganic acid residue or an organic acid residue, and typical examples of the DBN salt include DBN formate, DBN orthophthalate, DBN octylate, DBN Examples thereof include organic salts of DBN such as phenol salt, phenol novolac resin salt of DBN, and p-toluenesulfonate of DBN.

（上記一般式（５）中、Ｘは無機または有機の酸残基を表す）

(In the above general formula (5), X represents an inorganic or organic acid residue)

  In the general formula (5), X represents an inorganic acid residue or an organic acid residue. As typical examples of the DBU salt, DBU formate, DBU oleate, DBU orthophthalate, DBU Examples include DBU organic acid salts such as octylate, DBU phenol salt, DBU p-toluenesulfonate, and the like.

  Such a temperature-sensitive catalyst can be added to the above-mentioned urethane resin adhesive composition, and when heated, when it exceeds a predetermined temperature, it rapidly exhibits activity as a urethane catalyst. The resin adhesive composition is cured in a short time. Moreover, storage stability improves by adding the said catalyst. The addition amount of the temperature-sensitive catalyst is preferably 0.001 part by mass or more and 1.0 part by mass or less, more preferably 0.05 part by mass or more and 0.5 part by mass with respect to 100 parts by mass of the urethane prepolymer. It is as follows.

  Since 2-methyl-1,4-diazabicyclo [2,2,2] octane represented by the above formula (1) catalyzes the reaction between the isocyanate group of the urethane prepolymer and the active hydrogen on the adherend surface, The obtained adhesive is excellent in adhesiveness with various adherends such as a hardly adhesive coating plate. When the content of the above-mentioned 2-methyl-1,4-diazabicyclo [2,2,2] octane is in the above range, it is excellent in adhesiveness to various adherends such as a hardly adhesive coating plate, Excellent storage stability. The above-mentioned 2-methyl-1,4-diazabicyclo [2,2,2] octane is a known compound, and for example, a product commercially available as DABCO (Me-DABCO) from Air Products Japan Co., Ltd. is used. be able to. Use 2-methyl-1,4-diazabicyclo [2,2,2] octane acetate or propionate commercially available from Air Products Japan as DABCO (8154, DF). Can do.

  DBN represented by the above formula (2) and the above general formula (3) or a salt thereof is a known compound, and since a commercially available product can be used, it is not necessary to synthesize specially. For example, those commercially available as DBN from San Apro Co., Ltd., U-CAT1102 (octylate of DBN), U-CAT881 (DBN-phenol novolak resin salt), and the like can be used. DBU represented by the above formula (4) and the above general formula (5) or a salt thereof is, for example, as DBU from San Apro Co., Ltd., U-CAT SA102-50 (DBU-octylate), U-CAT SA112. (DBU-octylate), U-CAT SA106 (DBU-oleate), U-CAT SA506 (DBU-p-toluenesulfonate), U-CAT SA603 (DBU-formate), etc. You can use what you have.

  In addition, U-CAT SA-1, U-CAT SA-102, DABCO8154, DF, DC-1 / DC-2, BL-17, TAC, H-1010, 2002, 2003 manufactured by Air Products Japan Co., Ltd. X-542, X-543, VP-137, 1027, 1028, NC-IM, NC-EMC, NCX-1072, NCX-1075, and the like.

As the catalyst, in addition to the above temperature-sensitive catalyst, other amine catalysts, metal catalysts, and the like can be used. Examples of the amine catalyst include tertiary amines such as triethylamine, monoamines such as 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'-trimethylaminoethylethanol Alcohol amines such as triethanolamine, bis (2-dimethylaminoethyl) ether, ethylene glycol bis (3-dimethylaminopropyl) amine catalysts such as ether amines such as aminopropyl ether or these salt compounds, and the like.

  Examples of the metal catalyst include organometallic compounds such as tin octylate and alkali metal alcoholates. For example, dimethyl tin dilaurate, dibutyl tin dilaurate, dibutyl tin maleate, dibutyl tin diacetate, tin carboxylates such as tin octylate and tin naphthenate, titanates such as tetrabutyl titanate and tetrapropyl titanate, aluminum trisacetylacetonate, Organoaluminum compounds such as aluminum trisethylacetoacetate and diisopropoxyaluminum ethylacetoacetate, chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate, and metal octanoates such as lead octoate and bismuth octoate And metal catalysts such as

  Of the other catalysts, the combined use of a temperature-sensitive catalyst and another amine catalyst is desirable for allowing the resinification reaction and the foaming reaction to proceed in a well-balanced manner and obtaining a good polyurethane resin.

  The compounding amount of the catalyst is 0.05 parts by mass or more and 1.0 part by mass or less in the case of an amine catalyst, and 0.05 parts by mass or more and 0.5 parts by mass or less in the case of a metal catalyst with respect to 100 parts by mass of the polyol compound. It is preferable.

  In the urethane resin adhesive composition of the present embodiment, in addition to the above essential components, a solvent, an anti-aging agent, an antioxidant, as necessary, can be used as long as a suitable pot life can be secured during mixing. , UV absorbers, colorants such as pigments and dyes, softeners, plasticizers, reinforcing agents, fillers, dispersants, dehydrating agents, and adhesion-imparting agents. The additives and the like can be kneaded by a general method to obtain a composition, which can be used for vulcanization or crosslinking. The blending amounts of these additives can be conventional conventional blending amounts as long as the object of the present embodiment is not violated.

  The production method of the urethane resin adhesive composition of the present embodiment is not particularly limited. For example, it is possible to use a method in which each of the above essential components and optional components are sufficiently mixed in a closed container using a stirrer such as a mixing mixer.

  The usage method of the urethane resin adhesive composition of this embodiment is not particularly limited except for heating. For example, after being applied to an adherend, it is bonded to a non-adherent body, both adherends are pressed together to form an adhesive structure, and then heated at 80 ° C. for 10 minutes, for example, and cooled to room temperature. At this time, the heating temperature and time may be any temperature and time at which the amine catalyst can exhibit a catalytic function when heated to a predetermined temperature of 20 ° C. or higher and 90 ° C. or lower. The heating temperature and time can be appropriately set depending on the amine catalyst used.

  Thus, according to the urethane resin adhesive composition of the present embodiment, the following effects can be obtained. A blend of a polyfunctional polyol and a polyfunctional isocyanate is prepared as described above, and can be cured in a short time with an amine catalyst by heating to a predetermined temperature or higher.

  That is, a urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates, 2-methyl-1,4-diazabicyclo [2,2,2] octane, and 1,5-diazabicyclo [4]. , 3,0] nonene-5 or a salt thereof, and any one of 1,8-diazabicyclo [5,4,0] undecene-7 or a salt thereof, it has high strength and high elongation. Thus, a urethane resin adhesive composition having excellent adhesiveness can be provided.

  The urethane resin adhesive composition of the present embodiment is excellent in adhesive performance and flexibility not only from low temperature (about −20 ° C.) to normal temperature but also at high temperature (about 80 ° C.). Therefore, the urethane resin adhesive composition of this embodiment can be preferably used as a structural adhesive.

  Therefore, although the use of the urethane resin adhesive composition of the present embodiment is not particularly limited, it can be suitably used for, for example, a structural adhesive. As the adhesive, for example, it can be used as an adhesive for structural members such as automobiles and vehicles (bullet trains, trains), civil engineering, construction, building materials, woodworking, electricity, electronics, aircraft, and the space industry. In particular, examples of applications related to automobiles include adhesion of interior materials such as ceilings, doors, and sheets, automotive illumination lamps such as lamps, adhesion of exterior materials such as side moldings, and the like.

  As mentioned above, although the urethane resin adhesive composition of this invention was demonstrated in detail, this invention is not limited to said example, You may perform various change and improvement in the range which does not deviate from the summary of this invention.

  Hereinafter, the urethane resin adhesive composition according to the above-described embodiment will be specifically described with reference to examples, but this embodiment is not limited thereto.

<Preparation of urethane resin adhesive composition>
Each component shown in Table 1 was blended in the addition amount (part by mass) shown in the same table, and these were mixed uniformly to prepare each urethane resin adhesive composition shown in Table 1. Table 1 shows the addition amount (parts by mass) of each component in each Example and Comparative Example.

[Evaluation]
About each obtained urethane resin adhesive composition, the evaluation method of the physical property (breaking strength, breaking elongation, adhesiveness, foamability) after hardening was done by the method shown below. The results are shown in Table 1.

<Break strength>
Each urethane resin adhesive composition prepared as described above was applied to a plastic plate at room temperature, heated at 80 ° C. for 10 minutes, cooled to room temperature, and then punched with a JIS No. 3 dumbbell to prepare a test piece. . The obtained test piece was subjected to a tensile test at a tensile speed of 50 mm / min using a tensile tester (AGS-10 kNG, manufactured by Shimadzu Corporation) in accordance with JIS K6251 to measure the breaking strength (MPa). Those having a tensile breaking strength of 10 MPa or more were evaluated as “◯”. Those having a tensile strength at break of less than 10 MPa were evaluated as “x”. The evaluation results are shown in Table 1 below.

<Elongation at break>
Each urethane resin adhesive composition prepared as described above was applied to a plastic plate at room temperature, heated at 80 ° C. for 10 minutes, cooled to room temperature, and then punched with a JIS No. 3 dumbbell to prepare a test piece. . The obtained test piece was subjected to a tensile test at a tensile speed of 50 mm / min using a tensile tester (AGS-10 kNG, manufactured by Shimadzu Corporation) in accordance with JIS K6251, and the elongation at break (%) was measured. Those having a tensile elongation of 150% or more were evaluated as “◯”. Those having a tensile elongation of less than 150% were evaluated as “x”. The evaluation results are shown in Table 1 below.

<Adhesiveness>
After applying each urethane resin adhesive composition prepared above to one of the electrodeposition coated plates (25 × 100 × 0.8 mm) at room temperature, the two electrodeposited coated plates are bonded together and pressed. And after forming each adhesion structure, it heated at 80 degreeC for 10 minutes, and cooled to room temperature, and produced each adhesion structure. The length of the joined portion was 10 mm.

(Adhesion evaluation method)
Each adhesive structure was subjected to a 90 ° peel test in accordance with JIS K6256 to evaluate the state of destruction of the cured product of the adhesive composition. The evaluation criteria for adhesiveness are “◯” when the cured product of the adhesive composition is 100% cohesive failure, and “△” when the cured product of the adhesive composition peels at an area of 30% or less of the adhesion area. "The case where the cured | curing material of the adhesive composition peeled the interface in the area of more than 30% and 70% or less of the adhesion area was evaluated as" x ". The evaluation results are shown in Table 1 below.

<Foaming properties>
Each urethane resin adhesive composition prepared as described above was applied to an electrodeposition coated plate at room temperature, heated at 80 ° C. for 10 minutes, cooled to room temperature, and visually observed for foaming. The case where foaming was not confirmed visually was evaluated as “◯”. The case where foaming was confirmed visually was evaluated as “x”. The evaluation results are shown in Table 1 below.

Each component shown in Table 1 is as follows.
Polyol PPG2000: trade name “EXCENOL2020” (number average molecular weight: 2000), manufactured by Asahi Glass Co., Ltd. Polyol PPG1000: trade name “EXCENOL1020” (number average molecular weight: 1000), manufactured by Asahi Glass Co., Ltd. • Polyol PPG800: trade name “PPG” -800 "(number average molecular weight: 800), manufactured by Sanyo Chemical Industries, Ltd., Polyol PPG200: Trade name" PPG-200 "(number average molecular weight: 200), manufactured by Sanyo Chemical Industries, Ltd., carbon black: product name," Niteron "# 200 ", manufactured by Shin-Nippon Carbon Co., Ltd., Me-DABCO: Trade name" DABCO ", manufactured by Air Products Japan, Inc., DBN salt: Trade name" U-CAT1102 "(DBN octylate), San Apro Corporation Product / DBU salt: Trade name “U-CA” SA102-50 "(octyl acid salt of DBU), San-Apro Co., Ltd., a polyisocyanate compound: trade name" polymeric MDI, PAPI-135 ", Dow Chemical Japan Co., Ltd.

  From the results shown in Table 1, Examples 1 to 6 are all excellent in breaking strength and breaking elongation. Moreover, it turned out that adhesiveness and foaming property are also favorable. On the other hand, Comparative Example 1 not containing the first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less is inferior in breaking strength and does not contain the second polyfunctional polyol having a number average molecular weight of 1000 or more and 4000 or less. 2 was found to be inferior in elongation at break. Comparative Example 3 in which the content of the first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less is not in the range of 5% by mass or more and 50% by mass or less with respect to the sum of all polyfunctional polyols is inferior in breaking strength, It was found that Comparative Example 4 was inferior in breaking strength. It was found that Comparative Example 5 in which the blending amount of the polyfunctional isocyanate was not in the range of NCO / OH ratio of 0.8 or more and 1.2 or less was poor in adhesiveness, and Comparative Example 6 was inferior in foamability.

  Therefore, a urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates, 2-methyl-1,4-diazabicyclo [2,2,2] octane, and 1,5-diazabicyclo [4 , 3,0] nonene-5 or a salt thereof and 1,8-diazabicyclo [5,4,0] undecene-7 or a salt thereof, the polyfunctional polyol has a number average molecular weight. The first polyfunctional polyol having a number average molecular weight of 1000 or more and 4000 or less, and the first polyfunctional polyol and the second polyfunctional polyol have an average OH value. 150 or more and 800 or less, and the content of the first polyfunctional polyol is 5% by mass or more and 50% by mass or less with respect to the sum of all polyfunctional polyols. It has been found that a urethane resin adhesive composition having a CO / OH ratio of 0.8 or more and 1.2 or less has high strength and high elongation and is further excellent in adhesiveness.

Claims (1)

A urethane resin containing two or more polyfunctional polyols and one or more polyfunctional isocyanates;
2-methyl-1,4-diazabicyclo [2,2,2] octane;
Either 1,5-diazabicyclo [4,3,0] nonene-5 or a salt thereof and 1,8-diazabicyclo [5,4,0] undecene-7 or a salt thereof;
Containing
The polyfunctional polyol includes a first polyfunctional polyol having a number average molecular weight of 50 or more and 800 or less, and a second polyfunctional polyol having a number average molecular weight of 1,000 or more and 4000 or less,
The first polyfunctional polyol and the second polyfunctional polyol have an average OH value of 150 or more and 800 or less,
The content of the first polyfunctional polyol is 5% by mass or more and 50% by mass or less based on the sum of all polyfunctional polyols,
The polyfunctional isocyanate has an NCO / OH ratio of 0.8 or more and 1.2 or less, and is a urethane resin adhesive composition.