WO2019181798A1

WO2019181798A1 - Polyisocyanate composition and coating composition using same

Info

Publication number: WO2019181798A1
Application number: PCT/JP2019/010900
Authority: WO
Inventors: 高橋優; 長岡毅; 堀口健二; 野口周人
Original assignee: 東ソー株式会社
Priority date: 2018-03-20
Filing date: 2019-03-15
Publication date: 2019-09-26

Abstract

The present invention addresses the problem of providing: a polyisocyanate composition that enables the achievement of a coating film which is capable of exhibiting excellent coating film strength such as scratch resistance even in cases where a commonly used acrylic polyol is used, and which has excellent weather resistance and excellent adhesion; and a coating composition which uses this polyisocyanate composition as a curing agent. The problem is solved by a polyisocyanate composition which is characterized by containing (A) an urethane reaction product of hexamethylene diisocyanate and a diol that has a cyclic group and a molecular weight of 300 or less and (B) a nurated polyisocyanate which is obtained by nurating hexamethylene diisocyanate at an (A)/(B) ratio within the range of from 10/90 to 60/40 (mass ratio).

Description

Polyisocyanate composition and coating composition using the same

The present invention relates to a polyisocyanate composition and a coating composition using this as a curing agent.

Conventionally, non-yellowing polyisocyanates derived from aliphatic isocyanates such as 1,6-hexamethylene diisocyanate (hereinafter also referred to as HDI) are excellent in weather resistance, and thus are frequently used in the paint / coating and adhesive fields. It is used. Among them, the polyisocyanate type containing an isocyanurate bond has high chemical and thermal stability, and is particularly excellent in weather resistance, heat resistance, and durability. Therefore, it is widely used depending on its application. Application expansion is expected.

In recent years, plastic products such as mobile phone cases, personal computer cases, audio equipment, electronic material parts such as touch panels and liquid crystal screens, home appliances such as refrigerators, microwave ovens and washing machines, woodworking products such as furniture, golf clubs, In various fields, such as sports equipment such as tennis rackets, architectural interiors such as floors, sinks and doorknobs, and interior and exterior of automobiles, there is a demand for further enhancement of the surfaces.

In response to the above requirements, the surface hardness was increased by using a two-component curable polyurethane coating to provide a coating film having self-healing performance and imparting scratch resistance (Patent Documents 1 to 3) or by increasing the crosslinking density. A method for forming a coating film (Patent Document 4) is known. Patent Document 1 proposes a coating composition containing a specific polyester polyol, a polyisocyanate, and a tin-based urethanization catalyst as essential components. In Patent Document 2, toughness is further imparted by a resin composition containing, as essential components, a polyisocyanate compound having a specific isocyanate group equivalent and a polyester polyol having a specific range of average Tg, average number of functional groups, and number average molecular weight. It has been proposed to do. Patent Document 3 proposes a coating composition comprising a curing agent mainly composed of an allophanate-modified polyisocyanate containing no isocyanurate group, obtained by reacting a specific polyester polyol with a specific diol compound and an organic diisocyanate. ing. However, since the methods of Patent Documents 1 to 3 require the use of specific polyols, the above proposal is applied when acrylic polyols or the like generally used in the field where weather resistance is required. Even so, the scratch resistance is often insufficient, and improvements have been demanded. On the other hand, Patent Document 4 achieves high strength by using a specific polyisocyanate derived from isophorone diisocyanate (hereinafter referred to as IPDI), and the polyol is not limited, but has a performance contrary to high strength. Therefore, it is easy to impair the followability to the base material, and improvement has been demanded.

Japanese Unexamined Patent Publication No. Sho 63-86762 Japanese Unexamined Patent Publication No. 2012-121984 Japanese Unexamined Patent Publication No. 2006-124610 Japanese Laid-Open Patent Publication No. 2002-293873

The present invention has been made based on the circumstances as described above, and as a first problem, even when a general acrylic polyol is used, it is possible to express excellent coating strength such as scratch resistance, and weather resistance / It is providing the polyisocyanate composition which can obtain the coating film which is excellent in adhesiveness, and the coating composition which used this as a hardening | curing agent. As a second problem, even when a general acrylic polyol is used, a polyisocyanate composition capable of expressing an excellent coating film strength and capable of obtaining a coating film excellent in substrate followability, and this as a curing agent. It is in providing the coating composition prepared.

As a result of repeated studies, the present inventors can solve the above problems by using a polyisocyanate composition containing a polyisocyanate obtained by urethanation of a specific diol and HDI and a nurate type polyisocyanate. And reached the present invention.

That is, the present invention includes the following embodiments.

[1] A urethane reaction product (A) of HDI and a diol having a cyclic group having a molecular weight of 300 or less, and a nurate type polyisocyanate (B) obtained by nurating HDI, (A) / (B) = A polyisocyanate composition comprising 10/90 to 60/40 (mass ratio).

[2] It further includes a reaction product (C) of HDI nurate polyisocyanate (B1), a diol having a cyclic group having a molecular weight of less than 300 and HDI, and the molar ratio of (A) to (B) is 8 / The polyisocyanate composition according to the above [1], which is in the range of 92 to 92/8.

[3] The polyisocyanate composition as described in [2] above, wherein the reaction product (C) is contained in the polyisocyanate composition in an amount of 2% by mass or more.

[4] The diol having a cyclic group is a diol having at least one selected from the group consisting of a cycloalkyl ring, a benzene ring, and a heterocyclic ring, according to any one of the above [1] to [3] The polyisocyanate composition described.

[5] The polyisocyanate composition according to any one of [1] to [4], wherein the diol having a cyclic group is a diol having two or more cyclic groups.

[6] A polyurethane resin composition comprising the polyisocyanate composition according to any one of [1] to [5] and a polyol.

[7] A coating composition containing the polyurethane resin composition according to [6] above.

[8] A coating film formed from the coating composition according to [7] above.

According to the present invention, even when a general acrylic polyol is used, a polyisocyanate composition capable of expressing excellent coating strength such as scratch resistance, and obtaining a coating having excellent weather resistance and adhesion, and A coating composition using this as a curing agent can be obtained. In addition, a polyisocyanate composition capable of exhibiting excellent coating film strength even when a general acrylic polyol is used and capable of obtaining a coating film excellent in substrate followability, and a coating composition using this as a curing agent Can be obtained.

It is a figure which shows the GPC chromatogram of the polyisocyanate composition in 2nd embodiment.

Hereinafter, the present invention will be described in detail.

In the present invention, an embodiment that solves the first problem is referred to as a first embodiment, and an embodiment that solves the second problem is referred to as a second embodiment.

The polyisocyanate composition according to the first embodiment of the present invention includes a urethane reaction product (A) (hereinafter also referred to as component (A)) of HDI and a diol having a cyclic group having a molecular weight of less than 300, and It is a mixture containing a nurate type polyisocyanate (B) (hereinafter also referred to as component (B)).

HDI used in the polyisocyanate composition of the present invention is a kind of aliphatic diisocyanate monomer (hereinafter also simply referred to as aliphatic diisocyanate), and is a diisocyanate compound that does not contain a benzene ring in its structure. Aliphatic diisocyanates include HDI, tetramethylene diisocyanate, pentamethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate, etc. Can be mentioned. HDI may be used alone or in combination with other aliphatic diisocyanates, or in combination with alicyclic diisocyanates represented by isophorone diisocyanate or norbornene diisocyanate.

Component (A), which is one of the constituent components of the polyisocyanate composition of the present invention, is obtained by urethanization of the hydroxyl group of a diol and the isocyanate group of an aliphatic diisocyanate. It is. In some cases, the isocyanate group of the component (A) and the hydroxyl group of the diol further form a urethane bond to be polymerized.

[Wherein R ₁ represents a hexamethylene group. R ₂ represents a diol residue containing a cyclic group. ].

The diol having a cyclic group used for the component (A) of the present invention has a molecular weight of less than 300. A compound having a cyclic group such as a cyclohexyl ring, a benzene ring, or a naphthalene ring in the molecular skeleton is preferable.

Examples of such a compound having a cyclic group include cyclohexanediol, cyclohexanedimethanol, bis (β-hydroxyethyl) benzene, naphthalenediethanol, etc. Examples of compounds containing a plurality of cyclic structures include 2,2 ′ -Bis (4-hydroxycyclohexyl) propane, isosorbide and the like. Especially, an alicyclic group is preferable from the surface of a weather resistance, and what contains multiple cyclic structures is more preferable.

The component (B) which is a constituent component of the polyisocyanate composition of the present invention includes an isocyanurate group in which diisocyanate monomers are cyclopolymerized with each other, and is represented by the following formula. This may be a polyisocyanate having an isocyanurate group that is trimerized, pentamerized, or polymerized.

[Wherein R ₁ represents a hexamethylene group. ].

The mass ratio of the component (A) and the component (B) contained in the polyisocyanate composition of the present invention is in the range of (A) / (B) = 10/90 to 60/40. If the component (A) is less than the lower limit, sufficient scratch resistance may not be exhibited, and if it is greater than or equal to the upper limit, the weather resistance may be impaired.

In 2nd embodiment of this invention, the trimer component (B1) contained in a component (B) other than the component (A) which is a polyisocyanate composition concerning 1st embodiment, and a component (B). ) And a reaction product (C) of a diol having a cyclic group having a molecular weight of less than 300 and HDI (hereinafter also referred to as component (C)). Component (C) is represented by the following formula.

[Wherein R ₁ represents a hexamethylene group. R ₂ represents a diol residue having a cyclic group. ].

In the polyisocyanate composition of the present invention, when the component (C) is included in addition to the component (A) and the component (B) (second embodiment), the component (A) and the component ( The molar ratio of B) is preferably in the range of 8/92 to 92/8, and more preferably in the range of 25/75 to 55/45. If the reaction product (A) is less than the lower limit, the compatibility with the resin may be impaired, and if it exceeds the upper limit, sufficient coating strength may not be exhibited.

Moreover, it is preferable that 2 mass% or more of components (C) are contained in a polyisocyanate composition. By containing 2% by mass or more, it is possible to obtain the effect of increasing the hardness and the viscosity, and the effect of further improving the compatibility with other resins. In particular, the inclusion of component (C) can be expected to increase the compatibility between component (A) and component (B), and the range of composition ratio selection between component (A) and component (B) can be expanded. .

The content of component (C) can be determined by gel permeation chromatography (hereinafter referred to as GPC) measurement. In the typical GPC chromatogram of the polyisocyanate composition of the present invention shown in FIG. 1, the component (C) is indicated by a peak having a peak top near the retention time of 20.3 minutes. The area ratio of the peak in the whole (peak area%, hereinafter referred to as PA%) is calculated, and this is used as the content of the component (C). The GPC measurement conditions are those described later.

The PA% obtained by the GPC measurement of the present invention is treated equally as mass% because the difference in specific gravity of the composition contained in each peak is small.

Next, a specific method for producing the polyisocyanate composition of the present invention will be described.

<The manufacturing method (1st embodiment) of the composition containing a component (A) and a component (B)>
In the first step, an organic diisocyanate and a diol containing a cyclic group are charged in an amount in which the isocyanate group is excessive with respect to the hydroxyl group, and urethanized in the presence or absence of an organic solvent to produce an isocyanate group-terminated prepolymer. Polymer I is produced. Here, as a standard of the urethanization reaction, the presence or absence of completion is judged by the isocyanate group content and the refractive index increase value by the neutralization titration method.

In the first step, the reaction proceeds under nitrogen gas or a dry air stream.

Here, the “amount of excess isocyanate group” in the first step means that the molar ratio of the isocyanate group of the organic diisocyanate to the hydroxyl group of the monool is 3 to 70 in terms of R = isocyanate group / hydroxyl group. It is preferable to prepare such that R = 5 to 35, and it is more preferable to prepare such that R = 5 to 35. When the molecular weight is less than the lower limit, the molecular weight of the urethane reaction product becomes high, and handling may be deteriorated by increasing the viscosity. When the upper limit is exceeded, the product yield decreases, which may lead to a decrease in productivity.

In addition, the reaction temperature of the urethanization reaction of the present invention is preferably 20 to 150 ° C., more preferably 60 to 130 ° C. In the urethanization reaction, a known urethanization catalyst can be used. For example, organic metal compounds such as dibutyltin diacetate, dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof Etc. These catalysts can be used alone or in combination of two or more.

The reaction time of the urethanization reaction varies depending on the presence or absence of the catalyst, the type, and the temperature, but is generally within 10 hours, preferably 1 to 5 hours is sufficient.

Moreover, in the production of the urethane reaction product, a method of performing the reaction without including an organic solvent or a method of performing the reaction in the presence of the organic solvent is appropriately selected.

When performing the reaction in the presence of an organic solvent, an organic solvent that does not affect the reaction can be used. Examples of the organic solvent include aliphatic hydrocarbons such as octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, ketones such as methyl isobutyl ketone and cyclohexanone, esters such as butyl acetate and isobutyl acetate, ethylene glycol Ethyl ether acetate, propylene glycol monomethyl ether acetate, 3-methyl-3-methoxybutyl acetate, glycol ether esters such as ethyl-3-ethoxypropionate, ethers such as dioxane, halogens such as methylene iodide and monochlorobenzene And polar aprotic solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and hexamethylphosphonylamide. These solvents can be used alone or in combination of two or more.

The organic solvent used in the reaction is removed simultaneously with the removal of the free organic diisocyanate in the next second step.

In the purification step of the second step, free unreacted organic diisocyanate present in the reaction mixture is removed by thin film distillation or extraction with an organic solvent at 120 to 150 ° C. under a high vacuum of 10 to 100 Pa, for example. By the method, the residual unreacted organic diisocyanate residual content is adjusted to 1% by mass or less. In addition, when the residual content rate of organic diisocyanate exceeds an upper limit, there exists a possibility of causing the generation | occurrence | production of an odor and the fall of storage stability.

The urethane reaction product (A) obtained by purification can be converted to a blocked isocyanate by using a known blocking agent for the purpose of extending the pot life or making the coating composition one component. As a result, the blocked polyisocyanate is inactive at room temperature, but when heated, the blocking agent dissociates, and the isocyanate group is activated again, thereby causing a potential function to react with the active hydrogen group. Can be added.

The blocking agent that can be used in the present invention is a compound having one active hydrogen in the molecule, for example, an alcohol, alkylphenol, phenol, active methylene, mercaptan, acid amide, acid imide, There are imidazole, urea, oxime, amine, imide, and pyrazole compounds.

The number average molecular weight of the urethane reaction product obtained as described above obtained from gel permeation chromatography measurement (hereinafter referred to as GPC measurement or simply referred to as GPC) is preferably 400 to 2000, and more preferably 500 to 1000.

The urethane reaction product (A) obtained by a series of reactions can be mixed with the nurate polyisocyanate (B) to obtain the polyisocyanate composition of the present invention. The mass ratio of the urethane reaction product (A) and the nurate type polyisocyanate (B) is (A) / (B) = 10/90 to 60/40, preferably 30/70 to 50/50.

In addition, as a nurate type polyisocyanate (B), the commercial item containing a nurate type polyisocyanate can be used. Examples of such commercially available products include Coronate HX, Coronate HXR, Coronate HXLV (trade names, all manufactured by Tosoh Corporation), and the like.

<Method for Producing Composition Containing Component (A), Component (B), and Component (C) (Second Embodiment)>
When the component (C) is introduced in the present invention, it is preferable to use the following production method.

In the first step, an isocyanuration catalyst is charged into HDI and isocyanuration is carried out at 50 to 150 ° C. until the desired isocyanate group content and molecular weight are obtained in the presence or absence of an organic solvent. Isocyanate group-terminated prepolymer I is produced.

In the second step, the reaction is stopped by adding a reaction terminator to the isocyanate group-terminated prepolymer I.

In the third step, the isocyanate group-terminated prepolymer I is charged with an isocyanate group-terminated prepolymer I in an amount in which the isocyanate group is excessive with respect to the hydroxyl group, and urethanated at 20 to 150 ° C. Manufacturing. Here, as a standard of the urethanization reaction, the presence or absence of completion is judged by the isocyanate group content and the refractive index increase value by the neutralization titration method.

In these first to third steps, the reaction proceeds under nitrogen gas or a dry air stream.

In the fourth step, the isocyanate group-terminated prepolymer II is removed by thin film distillation or solvent extraction until the free HDI content is less than 1% by mass.

Here, as the isocyanurate-forming catalyst in the first step, a quaternary ammonium salt, a carboxylic acid metal salt, or the like can be used.

Examples of the quaternary ammonium salt include 2-hydroxypropyltrimethylammonium octylate (DABCO TMR, manufactured by Sankyo Air Products), tetramethylammonium acetate, tetrabutyltylammonium acetate, and the like. Examples of carboxylic acid metal salts include zinc salts, tin salts, zirconium salts, and the like of carboxylic acids such as acetic acid, propionic acid, undecyl acid, capric acid, octylic acid, and myristic acid. Two or more kinds can be used in combination.

The reaction terminator in the second step has a function of deactivating the catalyst. Specifically, inorganic acids such as phosphoric acid and hydrochloric acid, organic acids having a sulfonic acid group, a sulfamic acid group, and the like, and these Known compounds such as esters and acyl halides are used. These reaction terminators can be used alone or in combination of two or more. In addition, the addition time is preferably a rapid addition after completion of the reaction.

The addition amount of the reaction terminator varies depending on the kind of the reaction terminator and the catalyst used, but is preferably 0.5 to 10 equivalents, particularly preferably 0.8 to 5.0 equivalents of the catalyst. When there are few reaction terminators, the storage stability of the obtained polyisocyanate composition tends to be lowered, and when it is too much, the polyisocyanate composition may be colored.

In the third step, “the amount of the isocyanate group becomes excessive” means that the molar ratio of the isocyanate group of the organic diisocyanate to the hydroxyl group of the diol is 3 to 100 in terms of R = isocyanate group / hydroxyl group when the raw materials are charged. It is preferable to charge, and it is more preferable that R = 5 to 100. If it is less than the lower limit, the molecular weight of the reaction product becomes high, and there is a possibility that high viscosity and gelation may occur. When the upper limit is exceeded, the product yield may decrease, resulting in a decrease in productivity, and a sufficient coating strength may not be obtained.

In addition, the reaction temperature of the urethanization reaction of the present invention is preferably 20 to 150 ° C., more preferably 60 to 130 ° C. In the urethanization reaction, a known urethanization catalyst can be used.

In the first to third steps, a method for carrying out the reaction without containing an organic solvent or a method for carrying out the reaction in the presence of the organic solvent is appropriately selected.

When conducting the reaction in the presence of an organic solvent, it is preferable to use an organic solvent that does not affect the reaction. Examples of the organic solvent include aliphatic hydrocarbons such as octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, ketones such as methyl isobutyl ketone and cyclohexanone, esters such as butyl acetate and isobutyl acetate, ethylene glycol Ethyl ether acetate, propylene glycol monomethyl ether acetate, 3-methyl-3-methoxybutyl acetate, glycol ether esters such as ethyl-3-ethoxypropionate, ethers such as dioxane, halogens such as methylene iodide and monochlorobenzene And polar aprotic solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and hexamethylphosphonylamide. These solvents can be used alone or in combination of two or more.

The organic solvent used in the reaction is removed simultaneously with the removal of free HDI in the fourth step.

In the purification step of the fourth step, the isocyanate group-terminated prepolymer II is removed by thin film distillation or solvent extraction until the free HDI content is less than 1% by mass.

In the fourth step, for example, residual unreacted HDI present in the reaction mixture by removal by thin film distillation or extraction with an organic solvent at 120 to 150 ° C. under a high vacuum of 10 to 100 Pa. The rate is 1% by mass or less. In addition, when the residual content rate of HDI exceeds an upper limit, there exists a possibility of causing the generation | occurrence | production of an odor and the fall of storage stability.

The polyisocyanate composition obtained by refining can be made into a blocked isocyanate using a known blocking agent for the purpose of extending the pot life or making the coating composition one component. As a result, the blocked polyisocyanate is inactive at room temperature, but when heated, the blocking agent dissociates, and the isocyanate group is activated again, thereby causing a potential function to react with the active hydrogen group. Can be added.

The polyurethane resin composition of the present invention can be obtained by blending the polyol with the polyisocyanate composition obtained by the production method of the first embodiment and the second embodiment described above.

Here, the polyol used in the polyurethane resin composition of the present invention is not particularly limited, but is a compound containing active hydrogen as a reactive group with an isocyanate group, such as a polyester polyol, a polyether polyol, Polycarbonate polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, fluorine-based polyols, transesterification products of two or more polyols, and hydroxyl-terminated prepolymers that have undergone a urethanization reaction with polyisocyanates are preferably used. These can also be used as one kind or a mixture of two or more kinds.

<Polyester polyol>
Examples of the polyester polyol include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, fumaric acid, and other dicarboxylic acids or these One or more anhydrides such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9 Nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer One or more low molecular polyols having a molecular weight of 500 or less, such as acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, And those obtained from the polycondensation reaction. Also, lactone polyester polyols obtained from ring-opening polymerization of cyclic ester (so-called lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Furthermore, a polyester-amide polyol obtained by replacing a part of the low molecular polyol with a low molecular polyamine such as hexamethylene diamine, isophorone diamine or monoethanolamine or a low molecular amino alcohol can also be used.

<Polyether polyol>
Examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl Low in glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerol, trimethylolpropane, pentaerythritol, etc. Molecular polio Or compounds having 2 or more, preferably 2 to 3, active hydrogen groups such as low molecular weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. As polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, or the like, or alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, Mention may be made of polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as tetrahydrofuran.

<Polycarbonate polyol>
Examples of the polycarbonate polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol , Cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylo One or more of low molecular polyols such as rupropane and pentaerythritol, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphen Mention may be made of those obtained from dealcoholization reactions and dephenol reactions with diaryl carbonates such as nantril carbonate, diindanyl carbonate and tetrahydronaphthyl carbonate.

Also, a polyol obtained by a transesterification reaction between a polycarbonate polyol, a polyester polyol, and a low molecular weight polyol can be suitably used.

<Polyolefin polyol>
Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

<Acrylic polyol>
Examples of the acrylic polyol include acrylic acid ester and / or methacrylic acid ester (hereinafter referred to as (meth) acrylic acid ester), acrylic acid hydroxy compound and / or methacrylic acid having at least one hydroxyl group in the molecule that can be a reaction point. Examples thereof include those obtained by copolymerizing an acrylic monomer using a thermal compound, a light energy such as an ultraviolet ray or an electron beam, and the like with a hydroxy compound (hereinafter referred to as a (meth) acrylic acid hydroxy compound) and a polymerization initiator.

<(Meth) acrylic acid ester>
Examples of (meth) acrylic acid esters include alkyl esters having 1 to 20 carbon atoms. Examples of such (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth Alkyl (meth) acrylates such as hexyl acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate Esters; esters of (meth) acrylic acid such as cyclohexyl (meth) acrylate with alicyclic alcohols; (meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate it can. Such (meth) acrylic acid esters may be used alone or in combination of two or more.

<(Meth) acrylic acid hydroxy compound>
The (meth) acrylic acid hydroxy compound has, for example, at least one hydroxyl group in the molecule which can be a reaction point with polyisocyanate. Specifically, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate And hydroxy acrylate compounds such as 4-hydroxybutyl acrylate, 3-hydroxy-2,2-dimethylpropyl acrylate, and pentaerythritol triacrylate. Also, hydroxy methacrylate compounds such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate, and pentaerythritol trimethacrylate are exemplified. These (meth) acrylic acid hydroxy compounds may be used alone or in combination of two or more.

<Silicone polyol>
Examples of the silicone polyol include a vinyl group-containing silicone compound obtained by polymerizing γ-methacryloxypropyltrimethoxysilane and the like, and α, ω-dihydroxypolydimethylsiloxane having at least one terminal hydroxyl group in the molecule, α, ω- Mention may be made of polysiloxanes such as dihydroxypolydiphenylsiloxane.

<Castor oil-based polyol>
Examples of the castor oil-based polyol include linear or branched polyester polyols obtained by a reaction between a castor oil fatty acid and a polyol. Dehydrated castor oil, partially dehydrated castor oil partially dehydrated, and hydrogenated castor oil added with hydrogen can also be used.

<Fluorine-based polyol>
As a fluorine-type polyol, the linear or branched polyol obtained by the copolymerization reaction of a fluorine-containing monomer and the monomer which has a hydroxyl group as an essential component can be mentioned, for example. Here, the fluorine-containing monomer is preferably a fluoroolefin, for example, tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyl trifluoroethylene. Is mentioned. Examples of the monomer having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, and vinyl hydroxyalkyl crotonates. Examples thereof include monomers having a hydroxyl group, such as hydroxyl group-containing vinyl carboxylate or allyl ester.

Also, the polyol preferably has an active hydrogen group number (average functional group number) in one molecule of 1.9 to 6.0. When the number of active hydrogen groups is less than the lower limit, the physical properties of the coating film may be reduced. Moreover, when exceeding an upper limit, there exists a possibility that adhesiveness may fall.

The number average molecular weight of the polyol is preferably in the range of 750 to 50,000. If it is less than the lower limit, the adhesion may be reduced, and if it exceeds the upper limit, the solubility in a low-polar organic solvent may be lowered or the adhesion may be lowered.

Moreover, the polyurethane resin composition of the present invention can be suitably used as a coating composition. The blending ratio of the polyisocyanate composition and the polyol in the coating composition is not particularly limited, but the molar ratio of the isocyanate group in the isocyanate composition to the hydroxyl group in the polyol is R = isocyanate group / hydroxyl group. It is preferable to blend so as to be 0.5 to 2.5. If it is less than the lower limit, the hydroxyl group becomes excessive, which may cause a decrease in adhesion. Moreover, there exists a possibility that a crosslinking density may fall and durability and the mechanical strength of a coating film may fall. When the upper limit is exceeded, the isocyanate group becomes excessive and reacts with moisture in the air, which may cause swelling of the coating film and a decrease in adhesion.

Examples of the organic solvent used as a diluent solvent include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as ethyl acetate, butyl acetate, and cellosolve, alcohols such as butanol and isopropyl alcohol, toluene, xylene, and the like. From the group consisting of hydrocarbons such as cyclohexane, mineral spirits, naphtha and the like, it can be appropriately selected according to the purpose and application. These solvents may be used alone or in combination of two or more.

In addition, the coating composition can use a known urethanization catalyst as appropriate in consideration of pot life, curing conditions, working conditions, and the like. Specifically, organic metal compounds such as dibutyltin diacetate, dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof are selected and used. These catalysts can be used alone or in combination of two or more.

The curing conditions of the coating composition are not particularly limited, but the curing temperature is -5 to 120 ° C., the humidity is 10 to 95% RH, and the curing time is 0.5 to 168 hours. preferable.

The coating composition obtained according to the present invention may contain, for example, an antioxidant such as 2,6-di-tert-butyl-4-methylphenol, an ultraviolet absorber, a pigment, a dye, a solvent, Additives such as a flame retardant, a hydrolysis inhibitor, a lubricant, a plasticizer, a filler, an antistatic agent, a dispersant, a catalyst, a storage stabilizer, a surfactant, and a leveling agent can be appropriately blended.

Further, the coating composition obtained by the present invention is applied onto the surface of the adherend by a known method such as spraying, brushing, dipping, or coater to form a coating film.

The adherend is not particularly limited, and is stainless steel, phosphated steel, zinc steel, iron, copper, aluminum, brass, glass, slate, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate resin. , Polybutylene phthalate resin, polystyrene resin, AS resin, ABS resin, polycarbonate-ABS resin, 6-nylon resin, 6,6-nylon resin, MXD6 nylon resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyurethane resin, phenol resin , Melamine resin, polyacetal resin, chlorinated polyolefin resin, polyolefin resin, polyamide resin, polyether ether ketone resin, polyphenylene sulfide resin, NBR resin, chloroprene resin, SBR resin, SE An adherend formed of a material such as S resin, an olefin resin such as polyethylene or polypropylene subjected to corona discharge treatment or other surface treatment, or a coating layer that can be intermediately formed on the surface of the adherend was formed. An adherend can be used.

Since the film thickness of the coating film formed on the adherend surface layer is excellent in recoatability and durability, the film thickness of at least 10 μm may be formed on the adherend. When the film thickness is less than 10 μm, the durability is lowered, and there is a possibility that the coating film is torn by impact.

Since the polyisocyanate composition and the coating composition of the present invention are excellent in coating film strength and substrate followability, they can be suitably used for automotive coating applications.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, the% description in an Example is a mass reference | standard unless there is particular notice.

In addition, about the 1st embodiment and 2nd embodiment, it was set as the synthesis | combination 1 of the polyisocyanate composition, and the synthesis | combination 2 of the polyisocyanate composition, respectively, and each obtained composition was evaluated.

<Synthesis 1 of polyisocyanate composition (first embodiment)>
<Example 1>
In a 4-liter flask having a capacity of 1 liter equipped with a stirrer, a thermometer, a condenser tube, and a nitrogen gas introduction tube, 875 g of HDI (manufactured by Tosoh Corporation, NCO content: 49.9% by mass) and hydrogenated bisphenol A (Maruzen) 125 g (manufactured by Petrochemical Co., Ltd., hereinafter referred to as “HBPA”) were charged, and these were heated to 100 ° C. with stirring, and urethanated until reaching a predetermined reaction conversion rate. Here, excess HDI was removed from the reaction product by thin film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 290 g of polyisocyanate C-1.
100 g of polyisocyanate C-1 obtained by the above operation and coronate HXLV (polyisocyanurate, manufactured by Tosoh Corporation, NCO content: 23.1% by mass, hereinafter referred to as C-HXLV) were mixed at a ratio of 900 g, 1000 g of polyisocyanate composition P-1 was obtained.

<Examples 2 to 3>
Under the conditions shown in Table 2, C-1 and C-HXLV were mixed to obtain polyisocyanate compositions P-2 and P-3.

<Comparative Examples 1 and 2>
Under the conditions shown in Table 3, C-1 and C-HXLV were mixed to obtain polyisocyanate compositions P-4 and P-5.

<Comparative Example 3>
In a 4-liter flask having a capacity of 1 liter equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, 950 g of HDI and 50 g of 1,3-butylene glycol (manufactured by KH Neochem, hereinafter referred to as 1,3-BG) Were heated to 100 ° C. with stirring, and urethanated until a predetermined reaction conversion rate was reached. Here, excess HDI was removed from the reaction product by thin film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 230 g of polyisocyanate C-2.
100 g of polyisocyanate C-2 obtained by the above operation and 900 g of C-HXLV were mixed to obtain 1000 g of polyisocyanate composition P-6.

<Comparative Examples 4 to 5>
Under the conditions shown in Table 3, C-2 and C-HXLV were mixed to obtain polyisocyanate compositions P-7 and P-8.

<Comparative Example 6>
Into a 1 liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe, 940 g of HDI and 60 g of 1,4-cyclohexanedimethanol (manufactured by Nagase Sangyo Co., Ltd., hereinafter referred to as CHDM) were charged. These were heated to 40 ° C. with stirring, and urethanization reaction was performed for 1 hour. Thereafter, the temperature is raised to 60 ° C., and 0.1 g of zirconyl octylate (Daiichi Rare Element Chemical Co., Ltd.), which is an allophanate catalyst, is added to the reaction solution until a predetermined reaction conversion rate is reached at 110 ° C. After the reaction, 0.11 g of acidic phosphate ester (JP-508, manufactured by Johoku Chemical Industry Co., Ltd.) as a reaction terminator was added, and a termination reaction was performed at 60 ° C. for 1 hour. Here, excess HDI was removed from the reaction product by thin film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 320 g of polyisocyanate C-3.
100 g of polyisocyanate C-3 obtained by the above operation was mixed with 900 g of C-HXLV to obtain 1000 g of polyisocyanate composition P-9.

<Comparative Examples 7 to 8>
Under the conditions shown in Table 3, C-3 and C-HXLV were mixed to obtain polyisocyanate compositions P-10 and P-11.

<Comparative Example 9>
C-HXLV was used.

<Preparation of two-component coating composition (scratch resistance)>
As shown in Tables 4 and 5, the paint blending liquid for scratch resistance evaluation is blended with a polyol and a polyisocyanate composition so that R (molar ratio of isocyanate group / hydroxyl group) = 1.0, and further an organic solvent. Thus, a two-component coating composition (S-1 to S-12) was prepared so that the solid content was 50% by mass (unit: g). Here, acrylic polyol (trade name: Acrydic 49-394-IM, hydroxyl value: 25 mg KOH / g, solid content: 50% by mass, manufactured by DIC) is used as the polyol, and butyl acetate is used as the organic solvent. And titanium oxide CR-90 (manufactured by Ishihara Sangyo) was used as the pigment.

<Preparation of two-component coating composition (weather resistance, adhesion)>
As shown in Tables 6 and 7, the paint blending solution for weather resistance and adhesion evaluation was blended with polyol and polyisocyanate composition so that R (isocyanate group / hydroxyl molar ratio) = 1.0, Further, a two-component coating composition (S-1 to S-12) was prepared so that the solid content was 50% by mass with an organic solvent (the unit of blending amount was g). Here, acrylic polyol (trade name: Acrydic A-801, hydroxyl value: 50 mgKOH / g, solid content: 50% by mass, manufactured by DIC) is used as the polyol, and butyl acetate is used as the organic solvent. The pigment was prepared using titanium oxide CR-50 (Ishihara Sangyo).

<Coating method and test piece preparation>
The prepared two-component paint composition is defatted with methyl ethyl ketone (JIS G3141, trade name: SPCC-SB, treatment method: PF-1077, manufactured by Partec Co., Ltd.) using an applicator so as to have an arbitrary film thickness. Applied. Thereafter, heat treatment was performed in a dryer at a temperature of 60 ° C. for 1 hour, followed by curing for 7 days in an environment at a temperature of 23 ° C. and a relative humidity of 50% to obtain coating films S-1 to S-12.

<Scratch resistance evaluation>
The indentation hardness of a coating film (film thickness after drying of about 20 μm) prepared from the paint obtained by the formulation shown in Tables 4 and 5 was measured by a scratch resistance test under the following conditions. The results are shown in Tables 8 and 9. An evaluation A is good.
Test equipment: Fischer scope HM2000 (Fischer Instruments)
・ Indenter: Vickers diamond ・ Test temperature: 25 ℃
<Scratch resistance evaluation criteria>
The indentation hardness values were classified according to the following criteria.
・ 125 N / mm ² or more: (Evaluation) A
110 N / mm ² or more to less than 125 N / mm ² : (Evaluation) B
-Less than 110 N / mm < ² >: (Evaluation) C.

<Weather resistance evaluation>
An accelerated weather resistance test was performed on the coating film (film thickness after drying of about 20 μm) prepared from the paints obtained with the formulations shown in Tables 6 and 7 under the following conditions.
・ Test equipment: QUV (manufactured by Q-LAB)
・ Lamp: EL-313
・ Illuminance: 0.59 w / m2
・ Λmax: 313 nm
1 cycle: 12 hours [UV irradiation: 8 hours (temperature 70 ° C.), condensation: 4 hours (temperature 50 ° C.)]
Test time: 576 hours <Weather resistance evaluation criteria>
According to JIS Z8741, glossiness at 60 ° was measured with a gloss meter (product name: Micro-Gloss, manufactured by BYK), and gloss retention was calculated. The gloss retention was determined by the following formula. The results are shown in Tables 8 and 9. An evaluation A is good.
Gloss retention (%) = 100 × Glossiness after weathering test ÷ Initial glossiness (Formula)
・ 80% or more: (Evaluation) A
・ 70% to less than 80%: (Evaluation) B
-Less than 70%: (Evaluation) C.

<Preparation of metallic base paint for adhesion evaluation>
Aqueous acrylic polyol (product name: Bernock WE-303, manufactured by DIC) 25.0 g, rheology control agent (product name: BYK-425, manufactured by BYK) 0.5 g, antifoaming agent (product name: BYK-012) 0.5 g of BYK), 1.0 g of a wetting and dispersing agent (product name: DISPERBYK-192, manufactured by BYK) and 2.0 g of aluminum paste (product name: Alpaste WXM5660, manufactured by Toyo Aluminum Co., Ltd.) The viscosity was adjusted by adding 15.0 g of methanol.

<Adhesion evaluation>
The prepared metallic base paint is applied to a steel plate (JIS G3141, trade name: SPCC-SB, treatment method: PF-1077, manufactured by Partec Co.) degreased with methyl ethyl ketone by spraying so that the film thickness after drying is about 30 μm. did. Thereafter, it was cured for 30 minutes in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and heat-treated for 30 minutes at 60 ° C. Further, the two-component coating composition prepared in Table 4 was applied on the steel plate coated with the metallic base using an applicator, pre-dried at room temperature for 10 minutes, and then heat-treated in a dryer at 90 ° C. for 30 minutes. Then, heat treatment was performed for 10 hours at 80 ° C. to obtain a coating film.
<Adhesion evaluation criteria>
The obtained coating film was subjected to an adhesion test by a cross-cut method according to JIS K5600-5-6. The results are shown in Tables 8 and 9. An evaluation A is good.
・ Classification 0 to 1: A
・ Class 2 to 5: B

<Synthesis 2 of Polyisocyanate Composition (Second Embodiment)>
<Example 13>
961 g of HDI (manufactured by Tosoh Corporation, NCO content: 49.9% by mass) was charged into a four-necked flask having a capacity of 1 liter equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe, and this was brought to 60 ° C. After heating, 1 g of trimethyloctylammonium methyl carbonate (diethyl 2-ethylhexanol 10% diluted) as an isocyanurate conversion catalyst was added and reacted at 60 ° C. until the predetermined reaction conversion rate shown in Table 1 was reached. 0.17 g of acidic phosphate ester (JP-508, manufactured by Johoku Chemical Industry Co., Ltd.) as a reaction terminator was added, and the termination reaction was carried out at 60 ° C. for 1 hour. Into the reaction solution after the termination reaction, 37 g of hydrogenated bisphenol A (manufactured by Maruzen Petrochemical Co., Ltd., hereinafter referred to as HBPA) is charged and heated to 100 ° C. with stirring, and urethanated until a predetermined reaction conversion rate is reached. The reaction product C-4 was obtained. Here, excess HDI was removed from the reaction product C-4 by thin film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 290 g of a polyisocyanate composition P-13.
When P-13 was analyzed by gel permeation chromatography (GPC) under the following conditions, the reaction product (C) obtained from nurate polyisocyanate, diol having a cyclic group, and HDI had a retention time of about 20. It was detected at around 3 minutes (number average molecular weight of about 1100), and the area calculated from 20.13 minutes to 20.55 minutes was about 8 PA%.

<GPC: Measurement of molecular weight>
(1) Measuring instrument: HLC-8220 (manufactured by Tosoh Corporation)
(2) Column: TSKgel (manufactured by Tosoh Corporation)
・ G3000H-XL
・ G2500H-XL
・ G2000H-XL, G1000H-XL
(3) Carrier: THF (tetrahydrofuran)
(4) Detector: RI (refractive index) detector (5) Temperature: 40 ° C
(6) Flow rate: 1.000 ml / min
(7) Calibration curve: Standard polystyrene (manufactured by Tosoh Corporation)
F-80 (molecular weight: 7.06 × 105, molecular weight distribution: 1.05)
F-20 (molecular weight: 1.90 × 105, molecular weight distribution: 1.05)
F-10 (molecular weight: 9.64 × 104, molecular weight distribution: 1.01)
F-2 (molecular weight: 1.81 × 104, molecular weight distribution: 1.01)
F-1 (molecular weight: 1.02 × 104, molecular weight distribution: 1.02)
A-5000 (molecular weight: 5.97 × 103, molecular weight distribution: 1.02)
A-2500 (molecular weight: 2.63 × 103, molecular weight distribution: 1.05)
A-500 (molecular weight: 5.0 × 102, molecular weight distribution: 1.14)
(8) Sample solution concentration: 0.5% THF solution.

<Examples 14 to 15>
Polyisocyanate compositions P-14 and P-15 were obtained in the same manner as in Example 13 with the preparation shown in Table 10. The reaction product (C) contained in each of them was about 10 PA% for P-14 and about 4 PA% for P-15.

<Comparative Example 37>
As the polyisocyanate, HDI polyisocyanurate (trade name: Coronate HK, manufactured by Tosoh Corporation, hereinafter C-HK) was used.

<Comparative Example 38>
As the polyisocyanate, IPDI polyisocyanurate (trade name: VESTANAT T1890 / 100, manufactured by EVONIK) was used.

<Comparative Examples 39 to 42>
C-HK and T1890 were mixed (mass ratio) under the conditions shown in Table 11 to obtain polyisocyanate compositions P-18 to P-21.

<Preparation of two-component coating composition>
As shown in Table 12, the coating composition liquid for evaluation was prepared by blending a polyol and a polyisocyanate composition so that R (molar ratio of isocyanate group / hydroxyl group) = 1.0, and an organic solvent having a solid content of 50. The coating compositions (S-13 to S-21) were prepared so as to be% (unit of blending amount is g). Acrylic polyol (trade name: ACRYDIC 49-394-IM, hydroxyl value: 25 mg KOH / g, solid content: 50%, manufactured by DIC) is used as the polyol, and butyl acetate is used as the organic solvent. did.

<Coating method and test piece preparation>
The prepared coating composition was applied to a steel plate (JIS G3141, trade name: SPCC-SB, treatment method: PF-1077, manufactured by Partec Co., Ltd.) using an applicator so that the film thickness after drying was about 20 μm. Then, after drying for 1 hour in an environment at a temperature of 23 ° C. and a relative humidity of 50%, heat treatment is performed in a dryer at 80 ° C. for 12 hours, followed by an environment of 23 ° C. and a relative humidity of 50% for one day or more. Curing was performed to obtain coating films S-13 to S-21.

<Coating strength evaluation>
A scratch-resistant test was conducted on the coating film (film thickness after drying of about 20 μm) prepared from the paint obtained in the formulation shown in Table 12 under the following conditions in accordance with ISO 14577. The results are shown in Table 13. Evaluations A and B are good.
Test equipment: Fischer scope HM2000 (Fischer Instruments)
・ Indenter: Vickers diamond ・ Test load: 5 mN
Test temperature: 25 ° C
<Coating strength evaluation criteria>
・ 80 N / mm ² or more: (Evaluation) A
· 60 N / mm ² or more to less than 80 N / mm ² : (Evaluation) B
-Less than 60 N / mm < ² >: (Evaluation) C.

<Substrate followability evaluation>
A coating film (about 20 μm film thickness after drying) prepared from the paint obtained by the formulation shown in Table 12 was subjected to a substrate follow-up test by weight drop resistance according to JIS K5600-5-3. The results are shown in Table 13. Evaluations A and B are good.
<Base material follow-up evaluation criteria>
・ 100cm: (Evaluation) A
・ 90 cm to less than 100 cm: (Evaluation) B
-Less than 90 cm: (Evaluation) C.

<Preparation of metallic base paint for adhesion evaluation>
Aqueous acrylic polyol (product name: Bernock WE-303, manufactured by DIC) 25.0 g, rheology control agent (product name: BYK-425, manufactured by BYK) 0.5 g, antifoaming agent (product name: BYK-012) 0.5 g of BYK), 1.0 g of a wetting and dispersing agent (product name: DISPERBYK-192, manufactured by BYK) and 2.0 g of aluminum paste (product name: Alpaste WXM5660, manufactured by Toyo Aluminum Co., Ltd.) The viscosity was adjusted by adding 15.0 g of methanol, and a metallic base paint was obtained.

<Adhesion evaluation>
The prepared metallic base paint was applied to a steel plate (JIS G3141, trade name: SPCC-SB, treatment method: PF-1077, manufactured by Partec Co., Ltd.) by spraying so that the film thickness after drying was about 20 μm. Thereafter, it was cured for 30 minutes in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and heat-treated for 30 minutes at 60 ° C. Further, the coating composition prepared in Table 4 was applied on the steel plate coated with the metallic base coating using an applicator, pre-dried at room temperature for 10 minutes, and then heat-treated in a dryer at 90 ° C. for 30 minutes. After performing, it heat-processed on 80 degreeC conditions for 12 hours, and obtained the coating film. The obtained coating film was subjected to an adhesion test by a cross-cut method according to JIS K5600-5-6. The results are shown in Table 13. Evaluations A and B are good.
<Adhesion evaluation criteria>
・ Class 0: A
・ Category 1: B
・ Category 2-5: C

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

The specification, claims, and abstract of Japanese Patent Application No. 2018-053288 filed on March 20, 2018 and Japanese Patent Application No. 2018-115220 filed on June 18, 2018 are all included. The contents of which are hereby incorporated herein by reference.

1. 1. Chromatogram of polyisocyanate composition in the second embodiment Peak of reaction product (C) (shaded area)
3. Peak top of reaction product (C)

Claims

A urethane reaction product (A) of hexamethylene diisocyanate and a diol having a cyclic group having a molecular weight of 300 or less, and a nurate type polyisocyanate (B) obtained by nurating hexamethylene diisocyanate in a mass ratio of (A) / (B) = polyisocyanate composition characterized by containing in a range of 10/90 to 60/40.
It further includes a reaction product (C) of hexamethylene diisocyanate nurate polyisocyanate (B1), a diol having a cyclic group having a molecular weight of less than 300 and hexamethylene diisocyanate, and the molar ratio of (A) to (B) is 8 The polyisocyanate composition according to claim 1, wherein the polyisocyanate composition is in the range of / 92 to 92/8.
The polyisocyanate composition according to claim 2, wherein the reaction product (C) is contained in the polyisocyanate composition in an amount of 2% by mass or more.
The polyisocyanate composition according to any one of claims 1 to 3, wherein the diol having a cyclic group is a diol having at least one selected from the group consisting of a cycloalkyl ring, a benzene ring, and a heterocyclic ring. object.
The polyisocyanate composition according to any one of claims 1 to 4, wherein the diol having a cyclic group is a diol having two or more cyclic groups.
A polyurethane resin composition comprising the polyisocyanate composition according to any one of claims 1 to 5 and a polyol.
A coating composition comprising the polyurethane resin composition according to claim 6.
A coating film formed from the coating composition according to claim 7.