JP5726275B2 - adhesive - Google Patents

Description

  The present invention relates to a curing agent and a two-component curable polyurethane composition, and more particularly to a curing agent and a two-component curable polyurethane composition used for paints, inks, adhesives, and the like.

  Conventionally, a two-component curable polyurethane composition is prepared by preparing a curing agent containing a polyisocyanate and a main agent containing a macropolyol, and blending them at the time of use. It is used.

  As such a two-component curable polyurethane composition, for example, a main component polyol composition containing an acrylic polyol or a polyester polyol, and at least one diisocyanate selected from an aliphatic diisocyanate and an alicyclic diisocyanate as raw materials, an allophanate group A high solid paint composition including a curing agent composition containing a polyisocyanate composition having a high molecular weight is widely known (see, for example, Patent Document 1).

JP 2003-128989 A

  However, the high solid paint composition described in Patent Document 1 is excellent in weather resistance, but has insufficient adhesion, acid / alkali resistance, solvent resistance, stain resistance, etc. There is a problem that the design of the product is hindered. Therefore, for applications that require design properties, a resin composition having a good balance of adhesion, acid / alkali resistance, solvent resistance, stain resistance, weather resistance, and the like is required.

  An object of the present invention is to provide a curing agent capable of improving the adhesion, acid / alkali resistance, solvent resistance, stain resistance and weather resistance in a well-balanced manner, and a two-component curable polyurethane composition containing the curing agent. There is to do.

  In order to achieve the above object, the curing agent of the present invention is characterized by containing 30 to 90% by weight of a xylylene diisocyanate derivative and 10 to 70% by weight of a hexamethylene diisocyanate derivative.

  In the curing agent of the present invention, it is preferable that the xylylene diisocyanate derivative is a polyol-modified product of xylylene diisocyanate.

  In the curing agent of the present invention, it is preferable that the hexamethylene diisocyanate derivative is a biuret-modified product of hexamethylene diisocyanate and / or a trimer of hexamethylene diisocyanate.

  Moreover, the two-component curable polyurethane composition of the present invention is characterized by containing the curing agent and a polyol component.

  In the two-component curable polyurethane composition of the present invention, it is preferable that the polyol component contains an acrylic polyol.

  Moreover, in the two-component curable polyurethane composition of the present invention, it is preferable that the polyol component has a hydroxyl value of 5 to 200 mgKOH / g.

  According to the curing agent of the present invention and the two-component curable polyurethane composition containing the curing agent, adhesion, acid / alkali resistance, solvent resistance, contamination resistance, and weather resistance can be improved in a balanced manner. Therefore, the curing agent of the present invention and the two-part curable polyurethane composition containing the curing agent are suitably used in various industrial fields such as paints, inks, and adhesives.

  The curing agent of the present invention contains 30 to 90% by weight of xylylene diisocyanate derivative (hereinafter referred to as XDI derivative) and 10 to 70% by weight of hexamethylene diisocyanate derivative (hereinafter referred to as HDI derivative). It is out.

  XDI derivatives are derivatives of 1,3- or 1,4-xylylene diisocyanate or mixtures thereof (XDI), for example, multimers, biuret modified products, allophanate modified products, oxadiazine trione modified products, polyol modified products Examples include the body.

  Examples of XDI multimers include dimers (uretdione group-containing XDI), trimers (isocyanurate group-containing XDI), pentamers, heptamers, and the like. The XDI multimer is preferably an XDI trimer.

  The trimer of XDI can be obtained, for example, by reacting XDI in the presence of a known isocyanuration catalyst and trimerizing.

  The biuret modified form of XDI is obtained by, for example, reacting XDI with, for example, water, a tertiary alcohol (eg, t-butyl alcohol), a secondary amine (eg, dimethylamine, diethylamine, etc.), etc. It can be obtained by further reacting in the presence of a known biuretization catalyst.

  The allophanate-modified product of XDI can be obtained, for example, by reacting XDI with monoalcohol and then further reacting in the presence of a known allophanate catalyst.

  An oxadiazine trione modified product of XDI can be obtained, for example, by a reaction between XDI and carbon dioxide.

  A polyol modified product of XDI can be obtained, for example, by a reaction between XDI and a low molecular weight polyol.

  The low molecular weight polyol is a polyol having a number average molecular weight of less than 400, for example, ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 2-methyl-1 , 3-propanediol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, alkane ( C7-22) Diol, 2,6-dimethyl-1-octene-3,8-diol, cyclohexanedimethanol, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, bishydroxyethoxybenzene, xylene glycol , Bishydroxyethylene terephthalate, bisphe An alkylene oxide adduct of diol A or hydrogenated bisphenol A, diethylene glycol, trioxyethylene glycol, tetraoxyethylene glycol, pentaoxyethylene glycol, hexaoxyethylene glycol, dipropylene glycol, trioxypropylene glycol, tetraoxypropylene glycol, Diols such as pentaoxypropylene glycol and hexaoxypropylene glycol such as glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6 -Hexanetriol, trimethylolpropane, 2,2-bis (hydroxymethyl) -3-butanol and other aliphatic triols (8 to 24 carbon atoms) Which triols, for example, tetra methylol methane, D- sorbitol, xylitol, D- mannitol, polyols having four or more hydroxyl groups, such as D- mannitol, or mixtures thereof, and the like. Preferably, triol is used.

  These XDI derivatives can be used alone or in combination of two or more.

  Of the XDI derivatives, a polyol modified form of XDI is preferable.

  As the XDI derivative, a commercially available product can be used. Examples of such a product include Takenate D-110N (XDI trimethylolpropane modified, Mitsui Chemicals Polyurethane), Takenate D. -114N (modified biuret of XDI, manufactured by Mitsui Chemicals Polyurethanes).

  In addition, the NCO group content of the XDI derivative is, for example, 5 to 20% by weight, preferably 10 to 15% by weight, and the viscosity (25 ° C.) is, for example, 100 to 1000 mPa · s, preferably 300 to 700 mPa · s.

  When the viscosity of the XDI derivative exceeds the above range, the XDI derivative can be dissolved in a solvent and prepared as an XDI derivative solution.

  Examples of the solvent include ethyl acetate, butyl acetate, toluene, xylene, methylcyclohexane, propylene glycol monomethyl ether acetate (PMA), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone.

  These solvents can be used alone or in combination of two or more.

  The XDI derivative solution has a viscosity (25 ° C.) of, for example, 100 to 1000 mPa · s, preferably 300 to 700 mPa · s, and a solid content concentration of, for example, 60 to 90% by weight, preferably 70 It is prepared to be ˜80% by weight.

  The HDI derivative is a derivative of hexamethylene diisocyanate (HDI), and examples thereof include multimers, biuret modified products, allophanate modified products, oxazine trione modified products, and polyol modified products.

  Examples of HDI multimers include the same multimers as the XDI multimers described above, and examples include HDI dimers, trimers, pentamers, and heptamers. Preferably, a trimer of HDI is used.

  The trimer of HDI can be obtained, for example, by reacting HDI in the presence of a known isocyanuration catalyst and trimerizing.

  A biuret-modified product of HDI can be obtained, for example, by reacting HDI with, for example, water, a tertiary alcohol, a secondary amine or the like and then reacting in the presence of a known biuretization catalyst. .

  The allophanate-modified form of HDI can be obtained, for example, by reacting HDI with monoalcohol and then reacting in the presence of a known allophanate catalyst.

  An oxadiazine trione modified product of HDI can be obtained, for example, by a reaction of HDI and carbon dioxide.

  A polyol-modified product of HDI can be obtained, for example, by a reaction between HDI and the above-described low molecular weight polyol.

  These HDI derivatives can be used alone or in combination of two or more.

  Among HDI derivatives, preferred are HDI biuret modified, HDI trimer, and the like.

  In addition, as the HDI derivative, a commercially available product can be used. Examples of such a product include Takenate D-165N (HDI biuret modified product, Mitsui Chemicals Polyurethane Co., Ltd.), Takenate D-170N. (HDI trimer, Mitsui Chemicals Polyurethanes), Takenate D-178N (HDI allophanate modified, Mitsui Chemicals Polyurethanes) and the like.

  The NCO group content of the HDI derivative is, for example, 15 to 30% by weight, and preferably 20 to 25% by weight.

In addition to the XDI derivatives and HDI derivatives described above, isophorone diisocyanate derivatives (hereinafter referred to as IPDI derivatives), hydrogenated xylylene diisocyanate derivatives (hereinafter referred to as H ₆ XDI derivatives), dicyclohexylmethane, and the like. A diisocyanate derivative (hereinafter referred to as H ₁₂ MDI derivative) or the like can be used in combination.

  The IPDI derivative is a derivative of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), for example, a multimer of IPDI, a biuret modified product, an allophanate modified product, an oxadiazine trione. A modified body, a polyol modified body, etc. are mentioned.

  These IPDI derivatives can be used alone or in combination of two or more.

  In addition, as the IPDI derivative, a commercially available product can be used. Examples of such a product include Takenate D-140N (IPDI trimethylolpropane modified product, Mitsui Chemicals Polyurethane Co., Ltd.). It is done.

The H ₆ XDI derivative is a derivative of 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or a mixture thereof (hydrogenated xylylene diisocyanate, H ₆ XDI), for example, a multimer of H ₆ XDI , Biuret modified products, allophanate modified products, oxadiazinetrione modified products, polyol modified products and the like.

These H ₆ XDI derivatives can be used alone or in combination of two or more.

In addition, as the H ₆ XDI derivative, a commercially available product can be used. Examples of such a product include Takenate D-120N (trimethylolpropane modified product of H ₆ XDI, manufactured by Mitsui Chemicals Polyurethanes, Inc.). ), Takenate D-127N (H ₆ XDI trimer, Mitsui Chemicals Polyurethane).

H ₁₂ MDI derivatives are derivatives of 4,4′-, 2,4′- or 2,2′-dicyclohexylmethane diisocyanate or mixtures thereof (H ₁₂ MDI), for example, H ₁₂ MDI multimers, biurets A modified body, an allophanate modified body, an oxadiazine trione modified body, a polyol modified body, etc. are mentioned.

These H ₁₂ MDI derivatives can be used alone or in combination of two or more.

As the H _{12 MDI} derivatives, products can be used commonly available.

The curing agent is appropriately mixed with a polyisocyanate other than the polyisocyanate derivatives (XDI derivative, HDI derivative, IPDI derivative, H ₆ XDI derivative, H ₁₂ MDI derivative) as long as the effects of the present invention are not impaired. can do.

Examples of such polyisocyanates include aromatic polyisocyanates (for example, 4,4′-, 2,4′- or 2,2′-diphenylmethane diisocyanate or mixtures thereof (MDI), 2,4- or 2, 6-tolylene diisocyanate or a mixture thereof (TDI), 4,4′-toluidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), m- or p-phenylene diisocyanate or a mixture thereof, 4,4′-diphenyl Diisocyanates, aromatic diisocyanates such as 4,4′-diphenyl ether diisocyanate), araliphatic polyisocyanates (eg, 1,3- or 1,4-xylylene diisocyanate or mixtures thereof (XDI), 1,3- or 1 , 4-Tetra Tilxylylene diisocyanate or mixtures thereof (TMXDI), aromatic aliphatic diisocyanates such as ω, ω′-diisocyanate-1,4-diethylbenzene), alicyclic polyisocyanates (eg, 3-isocyanatomethyl-3,5, 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 4,4′-, 2,4′- or 2,2′-dicyclohexylmethane diisocyanate or mixtures thereof (H ₁₂ MDI), 1,3- or 1,4- bis (isocyanatomethyl) cyclohexane or mixtures thereof (hydrogenated xylylene _{diisocyanate,} H 6 XDI), bis (isocyanatomethyl) norbornane (NBDI), 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisopropyl Société 1,3-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, alicyclic diisocyanates such as methyl-2,6-cyclohexane diisocyanate), aliphatic polyisocyanates (for example, hexamethylene diisocyanate (HDI), tri Aliphatic diisocyanates such as methylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, 1,2-, 2,3- or 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate Etc.).

Then, an XDI derivative and an HDI derivative are mixed, and if necessary, an IPDI derivative, an H ₆ XDI derivative, an H ₁₂ MDI derivative, or the like is used in combination, and if necessary, other polyisocyanates are blended as appropriate. Obtain a curing agent.

  In the present invention, the mixing ratio of the XDI derivative and the HDI derivative is 30 to 90% by weight of the XDI derivative, 10 to 70% by weight of the HDI derivative, preferably 50 to 50% of the XDI derivative with respect to the total weight of the curing agent. 80% by weight, 20-50% by weight of the HDI derivative, more preferably 60-80% by weight of the XDI derivative and 20-40% by weight of the HDI derivative.

Further, the curing agent, IPDI _derivatives, H 6 XDI _derivatives, when used in combination, such as H 12 MDI derivatives, IPDI _derivatives, H 6 XDI _derivative, H 12 MDI derivatives and the like, relative to the total weight of the curing agent, For example, it mix | blends so that it may become 30 weight% or less, Preferably, it is 10 weight% or less.

In addition, when other polyisocyanates (polyisocyanates other than XDI derivatives, HDI derivatives, IPDI derivatives, H ₆ XDI derivatives, H ₁₂ MDI derivatives) are blended, the other polyisocyanates are added to the total weight of the curing agent. For example, it is blended so as to be 30% by weight or less, preferably 10% by weight or less.

  And the two-component curable polyurethane composition of this invention contains the above-mentioned hardening | curing agent and the polyol component prepared as a main ingredient.

  In the present invention, examples of the polyol component include macro polyols and low molecular weight polyols.

  The macropolyol is a polyol having a number average molecular weight of 400 to 10,000, and examples thereof include polyester polyol, polyether polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, natural oil polyol, polyolefin polyol, and acrylic polyol.

  The polyester polyol can be obtained by a known esterification reaction, that is, a condensation reaction between a polybasic acid and a polyhydric alcohol, a transesterification reaction between an alkyl ester of a polybasic acid and a polyhydric alcohol, or the like.

  Examples of the polybasic acid or its alkyl ester include aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and dimer acid, for example, fatty acids such as hexahydrophthalic acid and tetrahydrophthalic acid. Cyclic dicarboxylic acids such as aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid, or dialkyl esters thereof (for example, C 1-6 alkyl esters) or acid anhydrides thereof Or a mixture thereof.

  Examples of the polyhydric alcohol include the above-described low molecular weight polyols, preferably diols.

  The polyether polyol is, for example, an alkylene oxide having the above-described low molecular weight polyol as an initiator (for example, an alkylene having 2 to 5 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran, oxetane compound). Oxide) can be obtained by ring-opening homopolymerization or ring-opening copolymerization. Specific examples include polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene-propylene copolymer, and polyoxytetramethylene glycol (polytetramethylene ether glycol).

  The polycarbonate polyol can be obtained, for example, by reacting phosgene, dialkyl carbonate, diallyl carbonate, alkylene carbonate or the like in the presence or absence of a catalyst using the above-described low molecular weight polyol as an initiator. .

  In addition, the polyurethane polyol reacts with the above-mentioned polyisocyanate at a ratio in which the equivalent ratio of hydroxyl group to isocyanate group (OH / NCO) exceeds 1 with respect to the polyester polyol, polyether polyol and / or polycarbonate polyol obtained as described above. By making it, it can be obtained as a polyester polyurethane polyol, a polyether polyurethane polyol, a polycarbonate polyurethane polyol, or a polyester polyether polyurethane polyol.

  Examples of the epoxy polyol include an epoxy polyol obtained by a reaction of the above-described low molecular weight polyol with a polyfunctional halohydrin such as epichlorohydrin or β-methylepichlorohydrin.

  Examples of the natural oil polyol include hydroxyl group-containing natural oils such as castor oil and coconut oil.

  Examples of the polyolefin polyol include polybutadiene polyol, partially saponified ethylene-vinyl acetate copolymer, and the like.

  Examples of the acrylic polyol include a copolymer obtained by copolymerizing a hydroxyl group-containing acrylate and a copolymerizable vinyl monomer copolymerizable with the hydroxyl group-containing acrylate.

  Examples of the hydroxyl group-containing acrylate include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2,2-dihydroxymethylbutyl (meth) acrylate, polyhydroxyalkyl maleate, Examples thereof include polyhydroxyalkyl fumarate. Preferably, 2-hydroxyethyl (meth) acrylate etc. are mentioned.

  Examples of the copolymerizable vinyl monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and s-butyl ( Alkyl (meth) acrylates (C1-12) such as meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl acrylate, for example, styrene Aromatic vinyl such as vinyltoluene and α-methylstyrene, vinyl cyanide such as (meth) acrylonitrile, and carboxyl groups such as (meth) acrylic acid, fumaric acid, maleic acid and itaconic acid. Vinyl monomers or alkyl esters thereof, such as ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, oligoethylene glycol di (meth) acrylate, trimethylolpropane di (meth) ) Acrylates, alkane polyol poly (meth) acrylates such as trimethylolpropane tri (meth) acrylate, for example, vinyl monomers containing isocyanate groups such as 3- (2-isocyanato-2-propyl) -α-methylstyrene, and the like. It is done. Preferably, alkyl (meth) acrylate, aromatic vinyl, etc. are mentioned, More preferably, methyl (meth) acrylate, styrene, etc. are mentioned.

  The acrylic polyol can be obtained by copolymerizing these hydroxyl group-containing acrylate and copolymerizable vinyl monomer in the presence of a suitable solvent and polymerization initiator.

  As the acrylic polyol, a copolymer of 2-hydroxyethyl (meth) acrylate, methyl (meth) acrylate and styrene is preferably used.

  The acrylic polyol includes, for example, silicone polyol and fluorine polyol.

  Examples of the silicone polyol include an acrylic polyol in which a silicone compound containing a vinyl group such as γ-methacryloxypropyltrimethoxysilane is blended as the copolymerizable vinyl monomer in the copolymerization of the acrylic polyol described above. .

  As the fluorine polyol, for example, in the copolymerization of the acrylic polyol described above, as the copolymerizable vinyl monomer, for example, an acrylic polyol in which a fluorine compound containing a vinyl group such as tetrafluoroethylene or chlorotrifluoroethylene is blended may be mentioned. .

  The hydroxyl equivalent of the macropolyol is, for example, 200 to 5000, and preferably 250 to 4000.

  Moreover, the number average molecular weight of a macropolyol is 400-10000, for example, Preferably, it is 500-8000.

  The number average molecular weight of the macropolyol can be calculated from a known hydroxyl value measurement method such as an acetylation method or a phthalation method, and the number of functional groups of the initiator or the raw material.

  The low molecular weight polyol is a polyol having a number average molecular weight of less than 400, and examples thereof include the low molecular weight polyol described above.

  These polyol components can be used alone or in combination of two or more.

  As a polyol component, Preferably, a macro polyol is mentioned, More preferably, an acrylic polyol is mentioned.

  The hydroxyl value of the polyol component is, for example, 5 to 200 mgKOH / g, preferably 10 to 100 mgKOH / g. In addition, a hydroxyl value can be calculated | required from the acetylation method or phthalation method based on A method or B method of JISK1557-1.

  Moreover, the weight average molecular weight of a polyol component is 2000-100000, Preferably, it is 5000-50000 in standard polystyrene conversion by GPC measurement, for example.

  And the above-mentioned polyol component is dissolved in a solvent if necessary, and is prepared as a main agent.

  Examples of the solvent include the above-mentioned solvents, and preferably MEK, MIBK, ethyl acetate, butyl acetate and the like.

  In the two-component curable polyurethane composition, a curing agent and a main agent are blended at the time of use, mixed and stirred for use.

  The mixing ratio of the curing agent and the main agent is such that the equivalent ratio (OH / NCO) of the hydroxyl group in the main agent to the isocyanate group in the curing agent is, for example, 0.5 / 1.0 to 1.0 / 0.5. Preferably, it is adjusted to be 0.75 / 1.0 to 1.0 / 0.75.

  In addition, the curing agent and the main agent may be added to one or both of them as necessary, for example, epoxy resin, catalyst, coating improving agent, leveling agent, antifoaming agent, antioxidant, ultraviolet absorber, etc. In addition, additives such as stabilizers, plasticizers, surfactants, pigments (eg, titanium oxide), fillers, organic or inorganic fine particles, antifungal agents, silane coupling agents, and the like may be blended. The amount of these additives is appropriately determined depending on the purpose and application.

  According to the curing agent of the present invention and the two-component curable polyurethane composition containing the curing agent, adhesion, acid / alkali resistance, solvent resistance, contamination resistance, and weather resistance can be improved in a balanced manner. Therefore, the curing agent of the present invention and the two-part curable polyurethane composition containing the curing agent are suitably used in various industrial fields such as paints, inks, and adhesives.

  In addition, the two-component curable polyurethane composition of the present invention is suitably used particularly in applications that require design properties, such as automobile applications, architectural applications, home appliance applications, and information equipment applications such as personal computers and mobile phones. .

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

1) Preparation of curing agent Example 1
Takenate D-110N (XDI trimethylolpropane modified product, Mitsui Chemicals Polyurethanes Co., Ltd.) 75 parts by weight (solid content conversion value), Takenate D-165N (HDI biuret modified product, Mitsui Chemicals Polyurethanes Co., Ltd.) 25 parts by weight Mixing was performed to obtain a curing agent.

Examples 2-4 and Comparative Examples 1-5
The curing agents of Examples 2 to 4 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1, except that the formulation shown in Table 1 was used. In addition, all the compounding parts are solid content conversion values.

  The abbreviations and product names in Table 1 are shown below.

D-110N: modified trimethylolpropane of xylylene diisocyanate (NCO group content: 11.5% by weight, solid content concentration: 75% by weight, solvent: ethyl acetate, viscosity (25 ° C.): 500 mPa · s, Mitsui Chemicals (Made by polyurethane)
D-165N: Biuret modified product of hexamethylene diisocyanate (NCO group content: 23.3 wt%, solid content concentration: 100 wt%, viscosity (25 ° C.): 2300 mPa · s, manufactured by Mitsui Chemicals Polyurethanes)
D-170N: trimer of hexamethylene diisocyanate (NCO group content: 20.7% by weight, solid content concentration: 100% by weight, viscosity (25 ° C.): 2000 mPa · s, manufactured by Mitsui Chemicals Polyurethanes)
Evaluation 1) Preparation of coating film Curing agents obtained in Examples 1 to 4 and Comparative Examples 1 to 5, Olester Q612 (styrene-methyl methacrylate-2-hydroxyethyl (meth) acrylate copolymer, hydroxyl value) : 25 mg KOH / g, solid content concentration: 50% by weight, solvent: MIBK / butyl acetate = 8/2 (weight ratio, manufactured by Mitsui Chemicals, Inc.) and main component containing 50% by weight of titanium oxide per solid content As a result, a two-component curable polyurethane composition was obtained. Next, the obtained two-component curable polyurethane composition was applied to the surface of various plastic test pieces or metal test pieces (SPCC-SB (cold rolled steel plate), thickness 0.8 mm) on a bar coater. Then, each coating was applied so that the thickness after drying was 15 to 20 μm, and was allowed to stand at 23 ° C. and RH 50% for 1 week to form a coating film. The coating film thus obtained was used in the following tests.

2) Adhesion test (cross-cut adhesion)
In the production of the above 1) coating film, plastic test pieces made of polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), and polycarbonate (PC) are used as plastic test pieces, respectively. A coating film was formed in accordance with 1) preparation of the coating film.

  An adhesion test was performed on each of the obtained coating films by a grid pattern method (based on JISK5600-5-6). In the adhesion test, the number of cells remaining without being peeled after the test / the number of produced cells was defined as the adhesion evaluation. The results are shown in Table 1.

3) Impact resistance test (DuPont impact)
In preparation of said 1) coating film, the coating film was formed according to preparation of said 1) coating film using the metal test piece.

  Using a weight (500 g, 0.5 inch) with a DuPont impact tester, from the surface of the metal test piece where the coating film was formed (front surface) and from the surface where the coating film was not formed (back surface) An impact was applied, and the height of the weight when the coating film was damaged was measured. The results are shown in Table 1.

4) Acid / Alkaline test 5% by weight hydrochloric acid (5% HCl) and 5% by weight sodium hydroxide aqueous solution (5% NaOH) were spotted on the coating film and covered with a petri dish so as not to dry. After 24 hours, the traces of chemical removal were visually observed. The results are shown in Table 1.

    ○: No trace of chemicals was confirmed.

    Δ: Some traces of chemicals were confirmed.

    X: Traces of chemicals or abnormal coatings were confirmed.

5) Solvent resistance test A rubbing test (100 times, reciprocation) was performed on the coating film using gauze soaked in ethanol (EtOH), and then visually observed. The results are shown in Table 1.

    ○: No change in appearance was confirmed.

    Δ: Some change in appearance was confirmed.

    X: Change in appearance or scratch was confirmed.

6) Contamination resistance test The coating film was marked with magic ink (blue), wiped with ethanol after 24 hours, and the traces were visually observed. The results are shown in Table 1.

    ○: No trace of magic ink was confirmed.

    (Triangle | delta): The trace of magic ink was confirmed a little.

    X: Traces of magic ink were confirmed.

7) Weather resistance test The coating film was irradiated with ultraviolet rays continuously for 200 hours by an accelerated weather resistance tester (Due Panel Light Control Weather Meter, manufactured by Suga Test Instruments Co., Ltd.). It was measured with an expression color meter (manufactured by Nippon Denshoku). The difference (ΔE) in the E value before and after the ultraviolet irradiation was calculated to evaluate the degree of yellowing of the coating film. The results are shown in Table 1.

○: Yellowing was not confirmed. (ΔE <1)
Δ: Yellowing was slightly confirmed. (1 <ΔE <3)
X: Yellowing was confirmed. (3 <ΔE)

Claims (2)

An adhesive comprising a two-component curable polyurethane composition containing a curing agent and a polyol component,
The curing agent is
A curing agent for a two-part curable polyurethane composition in which a curing agent and a polyol component are blended at the time of use, mixed and stirred, and applied.
30 to 90% by weight of xylylene diisocyanate derivative and 10 to 70% by weight of hexamethylene diisocyanate derivative,
The xylylene diisocyanate derivative is a polyol-modified product of xylylene diisocyanate obtained by a reaction between xylylene diisocyanate and trimethylolpropane,
The hexamethylene diisocyanate derivative, biuret modified product of hexamethylene diisocyanate, and / or, Ri trimer der of hexamethylene diisocyanate,
An adhesive, wherein the polyol component includes an acrylic polyol . The adhesive according to claim 1, wherein the polyol component has a hydroxyl value of 5 to 200 mgKOH / g.