Polyisocyanate composition and coating agent

Abstract

To provide a polyisocyanate composition and a coating agent that can obtain a polyurethane resin with excellent breaking strength, breaking elongation, and solvent resistance.SOLUTION: A polyisocyanate composition includes an isocyanate group-terminated prepolymer. The isocyanate group-terminated prepolymer includes a reaction product of a polyisocyanate component and a polyol component. The polyisocyanate component includes an isocyanurate derivative of pentamethylene diisocyanate. The isocyanurate derivative of pentamethylene diisocyanate includes an isocyanurate modified product of pentamethylene diisocyanate partially modified with an alcohol component. The equivalent ratio (NCO / OH) of the isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component is 3 to 8. The second equivalent ratio (NCO / OH) of the isocyanate groups of pentamethylene diisocyanate to the hydroxyl groups of the alcohol component is 60 to 600.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyisocyanate composition and a coating agent. [Background technology]

[0002] Polyurethane resins are typically produced by reacting polyisocyanates with active hydrogen group-containing compounds. Polyurethane resins are widely used in various industrial fields, for example, as coating materials, adhesive materials, pressure-sensitive adhesive materials, and elastomers. For example, polyurethane resins are applied to any substrate to form a coating film. This allows the polyurethane resin to impart various physical properties to the substrate.

[0003] As the polyisocyanate, for example, a polyisocyanate composition obtained by the following method has been proposed: First, hexamethylene diisocyanate is reacted with a monohydric alcohol, followed by an isocyanuration reaction. Next, the reaction product obtained by the isocyanuration reaction is reacted with a polyester polyol (see, for example, Patent Document 1 (Synthesis Example 2, Example 5)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-139017 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, polyurethane resins are required to have both high breaking strength, high breaking elongation, and solvent resistance depending on the application. However, when the above-mentioned polyisocyanate composition is used, the resulting polyurethane resin may have insufficient breaking strength and solvent resistance.

[0006] The present invention provides a polyisocyanate composition and a coating agent that can provide a polyurethane resin that has excellent breaking strength, breaking elongation, and solvent resistance. [Means for solving the problem]

[0007] The present invention [1] is a polyisocyanate composition comprising an isocyanate-terminated prepolymer, wherein the isocyanate-terminated prepolymer comprises a reaction product of a polyisocyanate component and a polyol component, the polyisocyanate component comprises an isocyanurate derivative of pentamethylene diisocyanate, and the isocyanurate derivative of pentamethylene diisocyanate comprises an isocyanurate-modified product of pentamethylene diisocyanate partially modified with an alcohol component, the first equivalent ratio (NCO / OH) of the isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component is 3.0 or more and 8.0 or less, and the second equivalent ratio (NCO / OH) of the isocyanate groups of the pentamethylene diisocyanate to the hydroxyl groups of the alcohol component is 60 or more and 600 or less.

[0008] The present invention [2] comprises the polyisocyanate composition according to the above [1], wherein the isocyanurate derivative of pentamethylene diisocyanate comprises a mono-isocyanurate of pentamethylene diisocyanate, and the mono-isocyanurate of pentamethylene diisocyanate contains one isocyanurate group and is a derivative compound containing three molecules of pentamethylene diisocyanate, and in a chromatogram obtained by measuring the isocyanurate derivative of pentamethylene diisocyanate by gel permeation chromatography, the area ratio of the peak area corresponding to the mono-isocyanurate of pentamethylene diisocyanate to the area of ​​all peaks is 40% or more.

[0009] The present invention [3] includes the polyisocyanate composition according to the above [1] or [2], in which the number average molecular weight of the polyol component is 200 or more and 1,000 or less.

[0010] The present invention [4] includes the polyisocyanate composition according to any one of the above [1] to [3], wherein the average number of hydroxyl groups in the polyol component is 2.

[0011] The present invention [5] includes a coating agent comprising a base agent and a curing agent, wherein the base agent comprises a macropolyol, and the curing agent comprises the polyisocyanate composition according to any one of the above [1] to [4]. [Effects of the Invention]

[0012] In the polyisocyanate composition of the present invention, the polyisocyanate component for obtaining the isocyanate-terminated prepolymer contains an isocyanurate derivative of pentamethylene diisocyanate. The isocyanurate derivative of pentamethylene diisocyanate contains an isocyanurate-modified product of pentamethylene diisocyanate partially modified with an alcohol component. In the isocyanurate derivative of pentamethylene diisocyanate, the ratio (equivalent ratio) of pentamethylene diisocyanate to the alcohol component is within a predetermined range. The isocyanate-terminated prepolymer contains a reaction product obtained by reacting the polyisocyanate component and a polyol component at a predetermined ratio (equivalent ratio).

[0013] Therefore, the polyisocyanate composition can provide a polyurethane resin having excellent breaking strength, breaking elongation and solvent resistance.

[0014] The coating agent of the present invention contains the polyisocyanate composition, and therefore, a polyurethane resin having excellent breaking strength, breaking elongation, and solvent resistance can be obtained from such a coating agent. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a chromatogram obtained by measuring the isocyanurate derivative of pentamethylene diisocyanate in Synthesis Example 1 by gel permeation chromatography. DETAILED DESCRIPTION OF THE INVENTION

[0016] The polyisocyanate composition of the present invention contains an isocyanate-terminated prepolymer. The polyisocyanate composition preferably comprises an isocyanate-terminated prepolymer.

[0017] The isocyanate-terminated prepolymer comprises a reaction product of a polyisocyanate component and a polyol component. Preferably, the isocyanate-terminated prepolymer consists of a reaction product of a polyisocyanate component and a polyol component.

[0018] The polyisocyanate component includes an isocyanurate derivative of pentamethylene diisocyanate (PDI).

[0019] The isocyanurate derivative of pentamethylene diisocyanate includes an isocyanurate-modified product of pentamethylene diisocyanate that is partially modified with an alcohol component.

[0020] Examples of pentamethylene diisocyanates include 1,2-pentamethylene diisocyanate (1,2-pentane diisocyanate), 1,3-pentamethylene diisocyanate (1,3-pentane diisocyanate), 1,4-pentamethylene diisocyanate (1,4-pentane diisocyanate), and 1,5-pentamethylene diisocyanate (1,5-pentane diisocyanate). These can be used alone or in combination of two or more. A preferred example of the pentamethylene diisocyanate is 1,5-pentamethylene diisocyanate (1,5-pentane diisocyanate).

[0021] The alcohol component may be, for example, a low-molecular-weight alcohol. A low-molecular-weight alcohol is an organic compound having one or more hydroxyl groups in one molecule and having a relatively low molecular weight. Note that a relatively low molecular weight refers to a molecular weight of less than 200 (the same applies hereinafter).

[0022] Examples of low molecular weight alcohols include aliphatic low molecular weight alcohols and aromatic low molecular weight alcohols, and preferably aliphatic low molecular weight alcohols. Examples of aliphatic low molecular weight alcohols include aliphatic low molecular weight alcohols having 1 to 12 carbon atoms. Examples of aliphatic low molecular weight alcohols include aliphatic low molecular weight monools (monohydric alcohols) and aliphatic low molecular weight polyols (dihydric or higher alcohols).

[0023] The aliphatic low-molecular-weight monool is an aliphatic organic compound having one hydroxyl group per molecule and a relatively low molecular weight. Examples of the aliphatic low-molecular-weight monool include aliphatic low-molecular-weight monohydric alcohols having 1 to 12 carbon atoms. Examples of the aliphatic low-molecular-weight monohydric alcohols having 1 to 12 carbon atoms include alkyl alcohols having 1 to 12 carbon atoms. Examples of the alkyl alcohols having 1 to 12 carbon atoms include methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, 2-ethylhexyl alcohol, and lauryl alcohol. These can be used alone or in combination of two or more.

[0024] The aliphatic low-molecular-weight polyol is an aliphatic organic compound having two or more hydroxyl groups in one molecule and a relatively low molecular weight. Examples of the aliphatic low-molecular-weight polyol include aliphatic low-molecular-weight polyols having 1 to 12 carbon atoms. Examples of the aliphatic low-molecular-weight polyol include aliphatic low-molecular-weight dihydric alcohols, aliphatic low-molecular-weight trihydric alcohols, and aliphatic low-molecular-weight tetrahydric or higher alcohols.

[0025] More specifically, examples of aliphatic low-molecular-weight polyols include aliphatic low-molecular-weight dihydric alcohols having 1 to 12 carbon atoms, aliphatic low-molecular-weight trihydric alcohols having 1 to 12 carbon atoms, and aliphatic low-molecular-weight tetrahydric or higher alcohols having 1 to 12 carbon atoms. Examples of aliphatic low-molecular-weight dihydric alcohols having 1 to 12 carbon atoms include alkylene diols having 1 to 12 carbon atoms. Examples of alkylene diols having 1 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol. Examples of aliphatic low-molecular-weight trihydric alcohols having 1 to 12 carbon atoms include glycerin and trimethylolpropane. Examples of aliphatic low-molecular-weight tetrahydric or higher alcohols having 1 to 12 carbon atoms include pentaerythritol and diglycerin. These can be used alone or in combination of two or more types.

[0026] The low molecular weight alcohols can be used alone or in combination of two or more. The molecular weight of the low molecular weight alcohol (when used in combination, the average molecular weight (hereinafter the same)) is, for example, less than 200, preferably less than 150. The molecular weight of the low molecular weight alcohol is, for example, 40 or more, preferably 50 or more.

[0027] From the viewpoint of elongation at break, the average number of hydroxyl groups in the alcohol component is, for example, 1 or more. The average number of hydroxyl groups in the polyol component is, for example, 3 or less, preferably 2 or less. The average number of hydroxyl groups in the polyol component is particularly preferably 1.

[0028] More specifically, from the viewpoint of obtaining a polyurethane resin that combines breaking strength, breaking elongation, and solvent resistance, the alcohol component is preferably an aliphatic low-molecular-weight alcohol having 1 to 12 carbon atoms, more preferably an aliphatic low-molecular-weight monohydric alcohol having 1 to 12 carbon atoms, and an aliphatic low-molecular-weight dihydric alcohol having 1 to 12 carbon atoms, more preferably an aliphatic low-molecular-weight monohydric alcohol having 1 to 8 carbon atoms, even more preferably an aliphatic low-molecular-weight monohydric alcohol having 1 to 4 carbon atoms, and particularly preferably isobutyl alcohol.

[0029] An isocyanurate derivative of pentamethylene diisocyanate can be obtained, for example, by the following method. In this method, pentamethylene diisocyanate is first partially modified with an alcohol component (alcohol-modified). Then, the partially modified pentamethylene diisocyanate is subjected to an isocyanurate-forming reaction.

[0030] More specifically, in this method, pentamethylene diisocyanate and an alcohol component are first mixed in a predetermined ratio, and the pentamethylene diisocyanate is partially modified with the alcohol component.

[0031] In the isocyanurate derivative of pentamethylene diisocyanate, the blending ratio of pentamethylene diisocyanate to the alcohol component is adjusted so that the equivalent ratio (second equivalent ratio, NCO / OH) of the isocyanate group of pentamethylene diisocyanate to the hydroxyl group of the alcohol component falls within a predetermined range.

[0032] More specifically, the second equivalent ratio (NCO / OH) of the isocyanate groups of pentamethylene diisocyanate to the hydroxyl groups of the alcohol component is 60 or more, preferably 65 or more. Moreover, the second equivalent ratio (NCO / OH) of the isocyanate groups of pentamethylene diisocyanate to the hydroxyl groups of the alcohol component is 600 or less, preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, still more preferably 200 or less, and particularly preferably 100 or less.

[0033] The modification conditions (reaction conditions) for alcohol modification are not particularly limited and are set appropriately. Examples of reaction methods include bulk polymerization and solution polymerization. The environmental conditions are an inert gas atmosphere and normal pressure (atmospheric pressure). The reaction temperature is, for example, 20°C or higher, preferably 50°C or higher, and more preferably 70°C or higher. The reaction temperature is, for example, 100°C or lower, preferably 90°C or lower, and more preferably 80°C or lower. The reaction time is, for example, 30 minutes or longer, preferably 1 hour or longer. The reaction time is, for example, 12 hours or shorter, preferably 6 hours or shorter.

[0034] In addition, in the alcohol modification, a known organic solvent can be added in an appropriate ratio as needed. In addition, in the alcohol modification, a known urethane catalyst can be added in an appropriate ratio as needed. In addition, in the alcohol modification, a known additive can be added in an appropriate ratio as needed. Examples of additives include antioxidants, heat stabilizers, light stabilizers, and co-catalysts. These can be used alone or in combination of two or more types.

[0035] This produces an alcohol-modified reaction product liquid (hereinafter referred to as alcohol-modified liquid), which is a partially modified product of pentamethylene diisocyanate with an alcohol component.

[0036] More specifically, in the alcohol-modified solution, some of the pentamethylene diisocyanate molecules are modified with alcohol, i.e., the alcohol-modified liquid contains alcohol-modified pentamethylene diisocyanate (alcohol-modified PDI).

[0037] Furthermore, in the alcohol-modification, the remaining molecules of pentamethylene diisocyanate (the remainder of the portion that is alcohol-modified) remain unalcohol-modified. In other words, the alcohol-modified liquid contains pentamethylene diisocyanate that has not been alcohol-modified (alcohol-unmodified PDI).

[0038] That is, the alcohol-modified liquid contains a PDI composition that includes an alcohol-modified PDI and an alcohol-unmodified PDI. In other words, the PDI composition is a partially modified product of pentamethylene diisocyanate with an alcohol component, and is contained in the alcohol-modified liquid.

[0039] Next, in this method, an isocyanuration catalyst is added to the alcohol-modified liquid, and the mixture is heated as necessary, causing the isocyanate groups contained in the alcohol-modified liquid (the isocyanate groups of the alcohol-modified pentamethylene diisocyanate and the isocyanate groups of the unmodified pentamethylene diisocyanate) to undergo an isocyanuration reaction.

[0040] Examples of isocyanuration catalysts include tetraalkylammonium hydroxides, trialkylhydroxyalkylammonium hydroxides, weak organic acid salts thereof, metal salts of alkylcarboxylic acids, metal chelate compounds of β-diketones, Friedel-Crafts catalysts, organometallic compounds, and aminosilyl group-containing compounds. Metal salts of alkylcarboxylic acids are preferred. Examples of alkylcarboxylic acids include acetic acid, caproic acid, octylic acid, myristic acid, and naphthenic acid. Examples of metal salts include sodium salts, potassium salts, calcium salts, magnesium salts, tin salts, zinc salts, and lead salts. These can be used alone or in combination.

[0041] The isocyanuration catalyst may be used as a solution and / or dispersion. The solution and / or dispersion of the isocyanuration catalyst contains the above-mentioned isocyanuration catalyst and a known organic solvent. Examples of organic solvents include alkyl esters, alcohols, ethers, ketones, and nitriles. These can be used alone or in combination of two or more. The solids concentration of the solution (the content of the isocyanuration catalyst) is appropriately set depending on the purpose and application.

[0042] When the solution of the isocyanuration catalyst contains an alcohol, the alcohol serves as a solvent for the catalyst. The alcohol as a solvent is distinguished from the alcohol component described above. More specifically, the amount of the alcohol as a solvent is small compared to the amount of the alcohol component. More specifically, the amount of the alcohol as a solvent is, for example, 1 part by mass or less, preferably 0.5 parts by mass or less, per 100 parts by mass of pentamethylene diisocyanate.

[0043] The addition ratio of the isocyanurate catalyst (solid content equivalent) is, for example, 0.001 parts by mass or more, preferably 0.01 parts by mass or more, per 100 parts by mass of pentamethylene diisocyanate. The addition ratio of the isocyanurate catalyst (solid content equivalent) is, for example, 3.0 parts by mass or less, preferably 1.0 part by mass or less, per 100 parts by mass of pentamethylene diisocyanate. The isocyanurate catalyst may be added all at once or in portions.

[0044] The reaction conditions for the isocyanurate reaction are not particularly limited and are set appropriately. Examples of reaction methods include bulk polymerization and solution polymerization. The environmental conditions are an inert gas atmosphere and normal pressure (atmospheric pressure). The reaction temperature is, for example, 20°C or higher, preferably 50°C or higher, and more preferably 70°C or higher. The reaction temperature is, for example, 200°C or lower, preferably 150°C or lower, and more preferably 130°C or lower. The reaction time is, for example, 30 minutes or longer, preferably 1 hour or longer. The reaction time is, for example, 12 hours or shorter, preferably 6 hours or shorter.

[0045] In the isocyanurate reaction, a known organic solvent can be added in an appropriate ratio as needed. In the isocyanurate reaction, a known additive can be added in an appropriate ratio as needed. Examples of additives include antioxidants, heat stabilizers, light stabilizers, and co-catalysts. These can be used alone or in combination of two or more.

[0046] In the above-mentioned isocyanurate-forming reaction, a catalyst deactivator is preferably added at any timing. This stops the isocyanurate-forming reaction. Examples of catalyst deactivators include phosphoric acid, monochloroacetic acid, dodecylbenzenesulfonic acid, paratoluenesulfonic acid, orthotoluenesulfonic acid, benzoyl chloride, p-toluenesulfonamide, and o-toluenesulfonamide. These can be used alone or in combination of two or more. The blending ratio of the catalyst deactivator is not particularly limited and can be appropriately set depending on the purpose and application.

[0047] The catalyst deactivator is added, for example, when the conversion rate of isocyanate groups to isocyanurate (hereinafter referred to as the isocyanate group conversion rate) reaches a predetermined value. The isocyanate group conversion rate is, for example, 2% by mass or more, preferably 5% by mass or more, and more preferably 8% by mass or more. The isocyanate group conversion rate is, for example, 30% by mass or less, preferably 25% by mass or less, and more preferably 15% by mass or less. The isocyanate group conversion rate can be determined by a known measurement method. Examples of measurement methods include titration with di-n-butylamine and FT-IR analysis (the same applies hereinafter).

[0048] As a result, a reaction product liquid of the isocyanurate reaction (hereinafter referred to as an isocyanurate reaction liquid) is obtained.

[0049] The isocyanurate reaction liquid contains an isocyanurate derivative of pentamethylene diisocyanate.

[0050] The isocyanurate derivative of pentamethylene diisocyanate is an isocyanurate composition obtained by isocyanating the alcohol-modified liquid (a PDI composition containing an alcohol-modified PDI and an alcohol-unmodified PDI).

[0051] That is, the isocyanurate derivative of pentamethylene diisocyanate is an isocyanurate composition obtained by isocyanating pentamethylene diisocyanate that has been partially modified with an alcohol component.

[0052] In other words, the isocyanurate derivatives of pentamethylene diisocyanate include isocyanurates of alcohol-modified pentamethylene diisocyanate and isocyanurates of pentamethylene diisocyanate that are not alcohol-modified.

[0053] The isocyanurate derivative of pentamethylene diisocyanate preferably contains a mono-isocyanurate of pentamethylene diisocyanate in a predetermined proportion. The mono-isocyanurate is a derivative compound containing one isocyanurate group and three molecules of pentamethylene diisocyanate. In other words, the mono-isocyanurate is an isocyanate trimolecular compound containing three molecules of pentamethylene diisocyanate.

[0054] Each of the three pentamethylene diisocyanate molecules may be alcohol-modified PDI or alcohol-unmodified PDI.

[0055] From the viewpoints of breaking strength and solvent resistance, the content of the mono-isocyanurate nucleus of pentamethylene diisocyanate relative to the total amount of isocyanurate derivatives of pentamethylene diisocyanate is, for example, 20% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more. Also, the content of the mono-isocyanurate nucleus of pentamethylene diisocyanate relative to the total amount of isocyanurate derivatives of pentamethylene diisocyanate is, for example, 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less.

[0056] The content of mono-isocyanurate derivatives of pentamethylene diisocyanate is calculated based on a chromatogram obtained by measuring an isocyanurate derivative of pentamethylene diisocyanate by gel permeation chromatography (GPC measurement).

[0057] In the GPC measurement, the GPC measurement device and the GPC measurement method are not particularly limited, and any device and method having a resolution capable of calculating each area ratio of each peak can be appropriately adopted.

[0058] The method for calculating the area ratio of each peak is not particularly limited. Usually, each peak in a chromatogram obtained by GPC measurement is vertically divided, and the area ratio of each vertically divided peak is calculated by the area percentage method.

[0059] Then, in a chromatogram obtained by GPC measurement of an isocyanurate derivative of pentamethylene diisocyanate, a peak derived from an isocyanurate mononuclear compound is identified, and the area ratio of that peak is taken as the isocyanurate mononuclear compound content.

[0060] More specifically, the peak derived from the isocyanurate mononuclear compound is identified based on, for example, the polystyrene-equivalent molecular weight (average molecular weight). For example, a peak having a peak top in the polystyrene-equivalent molecular weight (number average molecular weight) range of 400 or more and less than 480 is identified as the peak derived from the isocyanurate mononuclear compound of pentamethylene diisocyanate.

[0061] The area ratio of the area of ​​the peak having a peak top in the range of polystyrene-equivalent molecular weight (number average molecular weight) of 400 or more and less than 480 to the area of ​​all peaks attributable to the isocyanurate derivative of pentamethylene diisocyanate (excluding peaks attributable to unreacted pentamethylene diisocyanate) (hereinafter, this may be referred to as the Mn400-480 area ratio or the isocyanurate mononuclear unit area ratio) is defined as the isocyanurate mononuclear unit content.

[0062] The area ratio of isocyanurate mononuclear bodies (e.g., Mn400-480 area ratio) is, for example, 20% or more, preferably 30% or more, more preferably 40% or more. The area ratio of isocyanurate mononuclear bodies (e.g., Mn400-480 area ratio) is, for example, 70% or less, preferably 60% or less, more preferably 50% or less.

[0063] The isocyanuration reaction liquid (i.e., the isocyanurate derivative of pentamethylene diisocyanate) may also contain an allophanate of pentamethylene diisocyanate.

[0064] More specifically, the isocyanuration catalyst may also function as an allophanation catalyst. That is, the isocyanuration reaction may produce an allophanate of pentamethylene diisocyanate together with the isocyanurate of pentamethylene diisocyanate. In such cases, the isocyanurate derivative of pentamethylene diisocyanate (including the isocyanurate of alcohol-modified pentamethylene diisocyanate and the isocyanurate of pentamethylene diisocyanate that is not modified with alcohol) contains the allophanate of pentamethylene diisocyanate.

[0065] In other words, the isocyanurate derivative of pentamethylene diisocyanate may be an isocyanurate derivative composition containing an isocyanurate and an allophanate. In the isocyanurate derivative composition, the content of allophanate groups is, for example, less than 50 mass%, preferably less than 45 mass%, more preferably less than 40 mass% based on the total amount of isocyanurate groups and allophanate groups (the same applies hereinafter).

[0066] The isocyanurate reaction liquid may contain, for example, unreacted pentamethylene diisocyanate in addition to the isocyanurate derivative of pentamethylene diisocyanate.

[0067] The unreacted pentamethylene diisocyanate is pentamethylene diisocyanate that has not been converted into an isocyanurate, and may be alcohol-modified PDI or alcohol-unmodified PDI.

[0068] When the isocyanurate reaction liquid contains unreacted pentamethylene diisocyanate, the unreacted pentamethylene diisocyanate can be separated from the isocyanurate reaction liquid by a known method, if necessary. Examples of the separation method include distillation and extraction. The separation conditions are appropriately set depending on the purpose and application.

[0069] The isocyanurate reaction liquid may contain an organic solvent, a urethanization catalyst, and / or an isocyanurate catalyst. In such cases, the organic solvent, the urethanization catalyst, and / or the isocyanurate catalyst can be separated from the isocyanurate reaction liquid as needed by a known method. Examples of separation methods include distillation and extraction. Separation conditions are appropriately set depending on the purpose and application.

[0070] Preferably, unreacted pentamethylene diisocyanate, the organic solvent, the urethanization catalyst and / or the isocyanuration catalyst are separated from the isocyanuration reaction liquid, whereby the isocyanuration reaction liquid preferably comprises an isocyanurate derivative of pentamethylene diisocyanate.

[0071] The isocyanate group concentration of the isocyanurate reaction liquid is, for example, 5.0% by mass or more, preferably 10.0% by mass or more. The isocyanate group concentration of the isocyanurate reaction liquid is, for example, 40.0% by mass or less, preferably 35.0% by mass or less, and more preferably 30.0% by mass or less. The isocyanate group concentration can be determined by a known measurement method. Examples of measurement methods include titration with di-n-butylamine and FT-IR analysis (the same applies below).

[0072] Furthermore, the polyisocyanate component may further contain other polyisocyanates, so long as it contains the isocyanurate derivative of pentamethylene diisocyanate.

[0073] The other polyisocyanates are polyisocyanates other than isocyanurate derivatives of pentamethylene diisocyanate. Examples of the other polyisocyanates include known polyisocyanate monomers and known polyisocyanate derivatives.

[0074] Examples of the polyisocyanate monomer include polyisocyanate monomers excluding pentamethylene diisocyanate monomers, and more specifically, for example, known aliphatic polyisocyanates (excluding pentamethylene diisocyanate), known alicyclic polyisocyanates, known araliphatic polyisocyanates, and known aromatic polyisocyanates.

[0075] Examples of polyisocyanate derivatives include polyisocyanate derivatives other than isocyanurate derivatives of pentamethylene diisocyanate, and more specifically, derivatives of the above polyisocyanate monomers. Examples of derivatives include polymers, isocyanurate derivatives, allophanate derivatives, biuret derivatives, uretdione derivatives, polyol adducts, urea derivatives, oxadiazinetrione derivatives, and carbodiimide derivatives. The polyisocyanate derivatives can be used alone or in combination of two or more.

[0076] The content of the other polyisocyanates is appropriately set within a range that does not impair the excellent effects of the present invention, and is, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 0% by mass, relative to the total amount of the polyisocyanate components.

[0077] In other words, the polyisocyanate component preferably does not contain any other polyisocyanates and consists of an isocyanurate derivative of pentamethylene diisocyanate.

[0078] As the polyol component, for example, a high molecular weight polyol has two or more hydroxyl groups in one molecule and is an organic compound with a relatively high molecular weight. Note that a relatively high molecular weight means a number average molecular weight of 200 or more, preferably a number average molecular weight of 300 or more (the same applies hereinafter).

[0079] Examples of high molecular weight polyols include polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, fluorine polyols, and vinyl monomer-modified polyols. These can be used alone or in combination of two or more. Preferred high molecular weight polyols include polyether polyols, polyester polyols, and polycarbonate polyols, and more preferably polycarbonate polyols.

[0080] The high-molecular-weight polyols can be used alone or in combination of two or more. The number-average molecular weight of the high-molecular-weight polyol is, for example, 200 or more, preferably 300 or more, and more preferably 400 or more. The number-average molecular weight of the high-molecular-weight polyol is, for example, 5000 or less, preferably 2000 or less, more preferably 1000 or less, even more preferably 800 or less, and particularly preferably 600 or less.

[0081] The polyol component may also be the low molecular weight polyol described above. These may be used alone or in combination of two or more kinds.

[0082] The polyol component can be used alone or in combination of two or more kinds. As the polyol component, a high molecular weight polyol is preferably used. The polyol component is preferably composed of a high molecular weight polyol.

[0083] In other words, the number average molecular weight of the polyol component is, for example, 200 or more, preferably 300 or more, and more preferably 400 or more. The number average molecular weight of the polyol component is, for example, 5000 or less, preferably 2000 or less, more preferably 1000 or less, even more preferably 800 or less, and particularly preferably 600 or less.

[0084] From the viewpoint of elongation at break, the average number of hydroxyl groups in the polyol component is, for example, 2 or more. The average number of hydroxyl groups in the polyol component is, for example, 4 or less, preferably 3 or less. The average number of hydroxyl groups in the polyol component is particularly preferably 2.

[0085] More specifically, from the viewpoint of obtaining a polyurethane resin that combines breaking strength, breaking elongation, and solvent resistance, preferred examples of the polyol component include divalent polyether polyols, divalent polyester polyols, and divalent polycarbonate polyols, and more preferred examples include divalent polycarbonate polyols.

[0086] In the polyisocyanate composition, the isocyanate-terminated prepolymer is obtained, for example, as a reaction product between the above-mentioned polyisocyanate component and the above-mentioned polyol component. Preferably, the isocyanate-terminated prepolymer is a reaction product obtained by a prepolymerization reaction between the polyisocyanate component and the polyol component. The polyisocyanate component and the polyol component are prepolymerized, for example, by the following method.

[0087] More specifically, in the production of an isocyanate-terminated prepolymer, a polyisocyanate component and a polyol component are blended in a predetermined ratio and subjected to a prepolymerization reaction. The blending ratio in the prepolymerization reaction is adjusted so that the equivalent ratio of the isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component (first equivalent ratio, NCO / OH) falls within a predetermined range.

[0088] More specifically, the first equivalent ratio (NCO / OH) of the isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component is 3.0 or more, preferably 4.0 or more, more preferably 5.0 or more, and even more preferably 5.5 or more. Also, the first equivalent ratio (NCO / OH) of the isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component is 8.0 or less, preferably 7.5 or less, more preferably 7.0 or less, and even more preferably 6.5 or less.

[0089] The reaction conditions for the prepolymerization reaction are not particularly limited and are set appropriately. Examples of reaction methods include bulk polymerization and solution polymerization. The environmental conditions are an inert gas atmosphere and normal pressure (atmospheric pressure). The reaction temperature is, for example, 20°C or higher, preferably 50°C or higher, and more preferably 70°C or higher. The reaction temperature is, for example, 150°C or lower, preferably 120°C or lower, and more preferably 100°C or lower. The reaction time is, for example, 30 minutes or longer, preferably 1 hour or longer. The reaction time is, for example, 12 hours or shorter, preferably 6 hours or shorter.

[0090] In the prepolymerization reaction, a known organic solvent can be added in an appropriate ratio as needed. In the prepolymerization reaction, a known prepolymerization catalyst can be added in an appropriate ratio as needed. In the prepolymerization reaction, a known additive can be added in an appropriate ratio as needed. Examples of additives include antioxidants, heat stabilizers, light stabilizers, and cocatalysts. These can be used alone or in combination of two or more types.

[0091] This results in a reaction product liquid of the prepolymerization reaction (hereinafter referred to as the prepolymerization reaction liquid). The prepolymerization reaction liquid contains a prepolymerization reaction product of the polyisocyanate component and the polyol component. The prepolymerization reaction liquid may also contain, for example, unreacted polyisocyanate component.

[0092] When the prepolymerization reaction solution contains an unreacted polyisocyanate component, the unreacted polyisocyanate component can be separated from the prepolymerization reaction solution by a known method, if necessary. Examples of the separation method include distillation and extraction. The separation conditions are appropriately set depending on the purpose and application.

[0093] The prepolymerization reaction solution may contain an organic solvent and / or a urethanization catalyst. In such cases, the organic solvent and / or the urethanization catalyst can be separated from the prepolymerization reaction solution as needed by a known method. Examples of the separation method include distillation and extraction. The separation conditions are appropriately set depending on the purpose and application.

[0094] The isocyanate group concentration of the prepolymerization reaction liquid is, for example, 3.0% by mass or more, preferably 5.0% by mass or more, and for example, 20.0% by mass or less, preferably 18.0% by mass or less, more preferably 16.0% by mass or less.

[0095] The polyisocyanate composition contains the above-described isocyanate group-terminated prepolymer. The polyisocyanate composition may also contain additives. The additives may be contained as optional components. Examples of additives include urethane catalysts, catalyst activity regulators, antioxidants, heat stabilizers, light stabilizers, UV absorbers, antiblocking agents, mold release agents, pigments, dyes, lubricants, fillers, hydrolysis inhibitors, rust inhibitors, and bluing agents. The amount and timing of addition of the additives are appropriately determined depending on the purpose and application.

[0096] The polyisocyanate composition may contain an organic solvent, or may not contain an organic solvent. The polyisocyanate composition preferably does not contain a solvent. The solid content concentration of the polyisocyanate composition is, for example, 95% by mass or more, preferably 99% by mass or more. The solid content concentration of the polyisocyanate composition is, for example, 100% by mass or less.

[0097] In addition, in the polyisocyanate composition (solid content (hereinafter the same)), the isocyanate monomer concentration (concentration of unreacted pentamethylene diisocyanate) is, for example, 5% by mass or less, preferably 2% by mass or less, more preferably 1% by mass or less. In addition, the isocyanate monomer concentration (concentration of unreacted pentamethylene diisocyanate) is usually 0% by mass or more.

[0098] The polyisocyanate composition has an isocyanate group concentration (based on the solid content) of, for example, 10% by mass or more, preferably 15% by mass or more. The polyisocyanate composition has an isocyanate group concentration of, for example, 30% by mass or less, preferably 25% by mass or less. The isocyanate group concentration can be determined by a known measurement method.

[0099] In the polyisocyanate composition, the polyisocyanate component for obtaining the isocyanate-terminated prepolymer contains an isocyanurate derivative of pentamethylene diisocyanate. The isocyanurate derivative of pentamethylene diisocyanate contains an isocyanurate of pentamethylene diisocyanate partially modified with an alcohol component. In the isocyanurate derivative of pentamethylene diisocyanate, the ratio (equivalent ratio) of pentamethylene diisocyanate to the alcohol component is within a predetermined range. The isocyanate-terminated prepolymer contains a reaction product obtained by reacting the polyisocyanate component and a polyol component at a predetermined ratio (equivalent ratio).

[0100] Therefore, the polyisocyanate composition can provide a polyurethane resin having excellent breaking strength, breaking elongation and solvent resistance.

[0101] The polyisocyanate composition is preferably used as a raw material component of polyurethane resin. The form of the polyurethane resin is not particularly limited, but examples thereof include one-component curing polyurethane and two-component curing polyurethane, and preferably two-component curing polyurethane. Examples of two-component curing polyurethane include paints, adhesives, and coating agents, and preferably coating agents.

[0102] The coating agent is a resin kit containing a base agent and a curing agent. The base agent and curing agent are prepared in separate packages and mixed at the time of use. The mixture is then applied and cured to form a polyurethane resin.

[0103] The base agent contains, for example, a macropolyol. Examples of the macropolyol include the high molecular weight polyols described above. More specifically, examples of the macropolyol include the polyether polyols described above, the polyester polyols described above, the polycarbonate polyols described above, the polyurethane polyols described above, the epoxy polyols described above, the vegetable oil polyols described above, the polyolefin polyols described above, the acrylic polyols described above, the fluorine polyols described above, and the vinyl monomer-modified polyols described above. These can be used alone or in combination of two or more. Preferred examples of the macropolyol include acrylic polyols and fluorine polyols, and more preferred examples include acrylic polyols.

[0104] The curing agent contains the polyisocyanate composition described above. The polyisocyanate composition described above may be dissolved in a known solvent, if necessary.

[0105] The base agent and curing agent are prepared separately and mixed together at the time of use. The mixing ratio of the base agent and curing agent is adjusted, for example, according to the equivalent ratio (third equivalent ratio, NCO / OH) of the isocyanate groups in the curing agent (polyisocyanate composition) to the hydroxyl groups in the base agent (macropolyol).

[0106] More specifically, the third equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent (polyisocyanate composition) to the hydroxyl groups in the base resin (macropolyol) is, for example, 0.5 or more, preferably 0.8 or more. Also, the third equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent (polyisocyanate composition) to the hydroxyl groups in the base resin (macropolyol) is, for example, 1.5 or less, preferably 1.2 or less.

[0107] The mixture of the base agent and the curing agent is then applied to the substrate by any coating method. Examples of coating methods include spray coating, air spray coating, brush coating, dipping, roll coating, flow coating, dry lamination, wet lamination, and direct coating. The substrate is not particularly limited, but examples include plastic films, fiber-reinforced plastics, metal foils, metal-deposited films, and steel materials. The amount of coating is appropriately determined depending on the purpose and application.

[0108] The mixture of the base resin and the curing agent is then dried and cured, thereby obtaining a cured polyurethane resin.

[0109] Such a coating agent contains the polyisocyanate composition as a curing agent, and therefore, the coating agent can produce a polyurethane resin having excellent breaking strength, breaking elongation, and solvent resistance.

[0110] Therefore, the polyisocyanate composition and the coating agent are suitable for use in various industrial fields, such as automotive paints, electronic equipment paints, and architectural paints. [Example]

[0111] Next, the present invention will be described based on production examples, examples, and comparative examples, but the present invention is not limited by the following examples. In addition, "parts" and "%" are based on mass unless otherwise specified. Further, specific numerical values such as blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "below" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0112] 1.GPC Samples were measured by gel permeation chromatography (GPC), and the area ratio of each peak area in the obtained chromatogram (chart) to the total peak area was determined.

[0113] And the area ratio (Mn400 - 480 area ratio) of the peak having a peak top in the range of polystyrene equivalent molecular weight of 400 or more and less than 480 was used as the monomer content rate contained in the isocyanurate derivative of pentamethylene diisocyanate.

[0114] In addition, about 0.03 g of the sample was dissolved in 10 mL of tetrahydrofuran. And the obtained solution was measured by GPC.

[0115] <GPC Measurement> · Analyzer: High-speed GPC device HLC-8320 (manufactured by Tosoh Corporation) · Detector: Differential refractive index detector · Eluent: Tetrahydrofuran · Separation column: The following (1) to (4) are connected in series (1) TSKgel guardcolum HXL-L 6.0×40 (manufactured by Tosoh Corporation) (2) TSKgel G1000HXL 7.8×300 (manufactured by Tosoh Corporation) (3) TSKgel G2000HXL 7.8×300 (manufactured by Tosoh Corporation) (4) TSKgel G3000HXL 7.8 x 300 (Tosoh Corporation) ·Measurement temperature: 40℃ ·Flow rate: 1mL / min ·Injection volume: 100μL ·Analysis device: Eco SEC (manufactured by Tosoh Corporation) <System Correction> Standard substance name: Polystyrene Calibration curve creation method: Using TOSOH TSKstandard polystyrene with different molecular weights, a graph of retention time and molecular weight was created. Polystyrene injection volume: 100 μL Polystyrene injection concentration: 1mg / mL

[0116] The isocyanurate derivative of pentamethylene diisocyanate of Synthesis Example 1 was used as a sample, and the chromatogram obtained by gel permeation chromatography is shown in FIG.

[0117] 2. Polyisocyanate component Synthesis Example 1 The following components were placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and the temperature was raised to 80°C. 1,5-pentamethylene diisocyanate (PDI) 100 parts by mass Irganox 1076 (antioxidant, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, product name, manufactured by BASF) 0.05 parts by mass JP-310 (promoter, tridecyl phosphite, product name, manufactured by Johoku Chemical Co., Ltd.) 0.1 parts by mass

[0118] Next, isobutanol (IBA, alcohol component) was added to the flask and heated at 80°C for 3 hours to partially modify the PDI with IBA. The amount of IBA was adjusted so that the equivalent ratio of the isocyanate groups of PDI to the hydroxyl groups of IBA (second equivalent ratio, NCO / OH) was 70.

[0119] Next, 0.01 parts by mass of N-(2-hydroxypropyl)-N,N,N-trimethylammonium-2-ethylhexanoate was dissolved in 0.03 parts by mass of propylene glycol methyl ether acetate to prepare a catalyst solution, which was then added to the flask.

[0120] The temperature inside the flask was then raised using the heat of reaction. As a result, the PDI partially modified with IBA was converted into an isocyanurate. Then, when the following reaction termination conditions were met, 0.01 parts by mass of o-toluenesulfonamide (a reaction terminator) was added to the flask to terminate the reaction. Reaction termination conditions Flask temperature: 120℃ Isocyanate group conversion rate: 10.7% by mass

[0121] The reaction product liquid in the flask was subjected to thin-film distillation (vacuum degree 50 Pa, temperature 150°C) to remove unreacted PDI, thereby obtaining a pentamethylene diisocyanate derivative.

[0122] Synthesis Examples 2-5 The amount of isobutanol added was changed so that the second equivalent ratio (the equivalent ratio of the isocyanate group of PDI to the hydroxyl group of IBA) would be the value shown in Tables 1 to 5. Other than this, a pentamethylene diisocyanate derivative was obtained in the same manner as in Synthesis Example 1.

[0123] Synthesis Example 6 A derivative of hexamethylene diisocyanate was obtained in the same manner as in Synthesis Example 1, except that 1,6-hexamethylene diisocyanate (HDI) was used instead of PDI.

[0124] Synthesis Examples 7-9 The amount of isobutanol added was changed so that the second equivalent ratio (the equivalent ratio of the isocyanate group of HDI to the hydroxyl group of IBA) would be the value shown in Tables 1 to 5. Other than this, a hexamethylene diisocyanate derivative was obtained in the same manner as in Synthesis Example 6.

[0125] Synthesis Example 10 The reaction termination conditions were changed as follows: A pentamethylene diisocyanate derivative was obtained in the same manner as in Synthesis Example 1. Reaction termination conditions Flask temperature: 100℃ Isocyanate group conversion rate: 5.0% by mass

[0126] Reference synthesis example 1 A derivative of hexamethylene diisocyanate was obtained by the same method as in Synthesis Example 2 of JP 2020-139017 A.

[0127] That is, in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, 1,000 parts by mass of 1,6-hexamethylene diisocyanate and 30 parts by mass of 2-ethylhexanol (2-EH) were alcohol-modified at 90°C for 1 hour.

[0128] Next, a catalyst solution was prepared by diluting tetramethylammonium caprate with isobutanol to 5% by mass. One part by mass of the catalyst solution was added to a flask, and an isocyanuration reaction was carried out. Phosphoric acid was then added to the flask at a predetermined timing to terminate the reaction. The reaction product was then purified by filtration and thin-film distillation. A hexamethylene diisocyanate derivative was thus obtained.

[0129] Reference synthesis example 2 A pentamethylene diisocyanate derivative was obtained in the same manner as in Example 1 of WO 2016 / 098771 (Patent No. 6386085).

[0130] That is, the following components were charged into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and a prepolymerization reaction was carried out at 80° C. for 2 hours. 1,5-pentamethylene diisocyanate (PDI) 1000 parts by mass PCD500 (polycarbonate diol, trade name ETERNACOLL UH-50, manufactured by Ube Industries, functional group number 2, number average molecular weight 500) 129.7 parts by mass 2,6-di(tert-butyl)-4-methylphenol 0.6 parts by mass Tris(tridecyl)phosphite 0.6 parts by mass

[0131] Next, the flask was cooled and adjusted to 60°C. Next, 0.15 parts by mass of an isocyanuration catalyst (N-(2-hydroxypropyl)-N,N,N-trimethylammonium-2-ethylhexanoate) was added to the flask, and an isocyanuration reaction was carried out for about 40 minutes. Thereafter, 0.15 parts by mass of o-toluenesulfonamide was added to the flask. The isocyanate group conversion rate was 20% by mass.

[0132] The resulting reaction product was then purified by thin-film distillation (vacuum degree 0.093 KPa, temperature 150°C). 0.02 parts by mass of o-toluenesulfonamide was added to 100 parts by mass of the purified product, yielding a pentamethylene diisocyanate derivative.

[0133] Reference synthesis example 3 A pentamethylene diisocyanate derivative was obtained in the same manner as in Example 12 of WO 2016 / 098771 (Patent No. 6386085).

[0134] That is, the following components were charged into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, and a prepolymerization reaction was carried out at 85° C. for 3 hours. 1,5-pentamethylene diisocyanate (PDI) 1000 parts by mass PCD500 (polycarbonate diol, trade name ETERNACOLL UH-50, manufactured by Ube Industries, functional group number 2, number average molecular weight 500) 162.2 parts by mass 2,6-di(tert-butyl)-4-methylphenol 0.6 parts by mass Tris(tridecyl)phosphite 0.6 parts by mass

[0135] Next, the inside of the flask was heated and adjusted to 100°C. Next, 0.05 parts by mass of an allophanate catalyst (lead octoate) was added to the flask to carry out an allophanate reaction. Thereafter, 0.15 parts by mass of o-toluenesulfonamide was added to the flask.

[0136] The resulting reaction product was then purified by thin-film distillation (vacuum degree 0.093 KPa, temperature 150°C). 0.02 parts by mass of o-toluenesulfonamide was added to 100 parts by mass of the purified product, yielding a pentamethylene diisocyanate derivative.

[0137] 3. Polyisocyanate composition Examples 1 to 15, Comparative Examples 1 to 10 and Reference Example 1 According to the formulations shown in Tables 1 to 5, a polyisocyanate component and a polyol component were charged into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube.

[0138] The amounts of the polyisocyanate component and the polyol component were adjusted so that the equivalent ratio (first equivalent ratio, NCO / OH) of the isocyanate group of the polyisocyanate component to the hydroxyl group of the polyol component would be the values ​​shown in Tables 1 to 5.

[0139] Next, the polyisocyanate component and the polyol component were subjected to a prepolymerization reaction at 90°C for 3 hours. It was then confirmed that the isocyanate group concentration in the reaction solution was equal to or less than the isocyanate group concentration calculated from the blending ratio of the polyisocyanate component and the polyol component. In other words, it was confirmed that all hydroxyl groups had reacted. This resulted in a polyisocyanate composition containing an isocyanate-terminated prepolymer.

[0140] Reference examples 2~3 The pentamethylene diisocyanate derivatives obtained in Reference Synthesis Examples 2 and 3 were used as polyisocyanate compositions.

[0141] 4. Evaluation (1) Appearance of polyurethane resin composition (a) Turbidity At the end of the synthesis of the polyisocyanate composition, the turbidity of the reaction product liquid was visually confirmed and evaluated according to the following criteria. ○: No turbidity (floating microgel particles) was observed. ×: Turbidity (floating microgel particles) was observed.

[0142] (2) Physical properties of polyurethane resin (a) Formation of coating film Each polyisocyanate composition was prepared as a curing agent. An acrylic polyol was prepared as a base resin. The acrylic polyol was Olester Q182 (trade name, manufactured by Mitsui Chemicals, Inc., hydroxyl value 45 mg KOH / g, solid content 50%).

[0143] Next, the base resin and curing agent were mixed so that the equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent to the hydroxyl groups in the base resin was 1.0. Furthermore, a mixed solvent was added to the mixture, and the mixture was mixed at 23°C for 5 minutes to adjust the solids concentration to 50% by mass. The mixed solvent was a mixture of 100 parts by mass of ethyl acetate, 100 parts by mass of butyl acetate, and 100 parts by mass of propylene glycol monomethyl ether acetate.

[0144] The mixture was then ultrasonicated for 10 minutes and degassed. This yielded a coating solution. The coating solution was then applied to a polypropylene plate and a steel plate (SPCC steel plate, PBN-144 treated) to obtain a coating film. A 4 mil applicator was used for the coating. The coating film was then heated in an oven at 80°C for 60 minutes to obtain a cured coating film (polyurethane resin). The cured coating film was then aged for 7 days in a constant temperature room at 23°C and 55% humidity.

[0145] (b) Tensile test Using the cured coating film formed on a polypropylene plate, an evaluation sample measuring 1 cm wide x 10 cm long was prepared. The film thickness was measured at three points near the center of the sample using a film thickness meter (dual type film thickness meter LZ990, manufactured by Kett Electric Laboratory), and the average value was taken as the film thickness of the sample. It was confirmed that the film thickness of each sample was approximately the same (approximately 40 μm).

[0146] Thereafter, the breaking strength and breaking elongation of each sample were measured five times under the following conditions, and the average values ​​were calculated. The average values ​​are shown in Tables 1 to 5. Tensile testing machine: Model 201B (manufactured by Intesco) Zipper spacing: 5cm Tensile speed: 50 mm / min Temperature: 23℃ Humidity: 55%

[0147] The evaluation criteria for breaking strength are as follows. ◎: 35MPa or more 〇: 30MPa or more and less than 35MPa △: 25MPa or more and less than 30MPa ×: Less than 25 MPa

[0148] The evaluation criteria for breaking elongation are as follows. ◎: 45% or more 〇: 30% or more but less than 45% △: 10% or more but less than 30% ×: Less than 10%

[0149] (c) Solvent resistance The cured coating film formed on the steel plate was set in a rubbing tester (Model IMC-0717, manufactured by Imoto Manufacturing Co., Ltd.). Absorbent cotton moistened with methyl ethyl ketone was placed on the end of a 2 kg weight. The cured coating film was then rubbed. The number of rubbing strokes at which the cured coating film broke and the steel plate was exposed was then measured.

[0150] The evaluation criteria for solvent resistance are as follows. ◎: 50 or more round trips 〇: 40 to less than 50 round trips △: 30 to less than 40 round trips ×: Less than 30 round trips

[0151] (3) Discussion (a) First equivalent ratio As seen in Examples 1 to 3 and Comparative Examples 1 and 2, when pentamethylene diisocyanate was used, significant changes in the physical properties of the polyurethane resin were confirmed by changing the first equivalent ratio. More specifically, by adjusting the first equivalent ratio within a predetermined range, a polyurethane resin having good breaking strength, breaking elongation, and solvent resistance was obtained.

[0152] On the other hand, as seen in Comparative Examples 1 to 3, when hexamethylene diisocyanate was used instead of pentamethylene diisocyanate, no significant changes in the physical properties of the polyurethane resin were observed even when the first equivalent ratio was changed.

[0153] (b) Second equivalent ratio As seen in Examples 16 to 17 and Comparative Examples 6 to 7, when pentamethylene diisocyanate was used, significant changes in the physical properties of the polyurethane resin were confirmed by changing the second equivalent ratio. More specifically, by adjusting the second equivalent ratio within a predetermined range, a polyurethane resin having good breaking strength, breaking elongation, and solvent resistance was obtained.

[0154] On the other hand, as seen in Comparative Examples 8 to 10, when hexamethylene diisocyanate was used instead of pentamethylene diisocyanate, no significant changes in the physical properties of the polyurethane resin were observed even when the second equivalent ratio was changed.

[0155] [Table 1]

[0156] [Table 2]

[0157] [Table 3]

[0158] [Table 4]

[0159] [Table 5]

[0160] Details of the abbreviations in the table are given below. PDI: Pentamethylene diisocyanate HDI: Hexamethylene diisocyanate 1,3BG: 1,3-butanediol IBA: Isobutyl alcohol 2-EH: 2-ethylhexanol PCD (number average molecular weight 500): Polycarbonate diol, ETERNACOLL UH-50 manufactured by Ube Industries, Ltd. PCD (number average molecular weight 1000): Polycarbonate diol, ETERNACOLL UH-100 manufactured by Ube Industries, Ltd. PCD (number average molecular weight 2000): Polycarbonate diol, ETERNACOLL UH-200 manufactured by Ube Industries, Ltd. PCL (bifunctional, number average molecular weight 530): Polycaprolactone diol (polyester diol) manufactured by Daicel Corporation, Plaxel 205 PCL (trifunctional, number average molecular weight 550): Polycaprolactone diol (polyester triol) manufactured by Daicel Corporation, Plaxel 305 PCL (bifunctional, number average molecular weight 1000): Polycaprolactone diol (polyester diol) manufactured by Daicel Corporation, Plaxel 210 PCL (bifunctional, number average molecular weight 1250): Polycaprolactone diol (polyester diol) manufactured by Daicel Corporation, Plaxel 212 PCL (bifunctional, number average molecular weight 2000): Polycaprolactone diol (polyester diol) manufactured by Daicel Corporation, Plaxel 220 PTMG (number average molecular weight 225): Polytetramethylene ether glycol, Mitsubishi Chemical Corporation, PTMG250 PTMG (number average molecular weight 650): Polytetramethylene ether glycol, Mitsubishi Chemical Corporation, PTMG650 PTMG (number average molecular weight 1000): Polytetramethylene ether glycol, Mitsubishi Chemical Corporation, PTMG1000 PTMG (number average molecular weight 2000): Polytetramethylene ether glycol, Mitsubishi Chemical Corporation, PTMG2000

Claims

1. A polyisocyanate composition comprising an isocyanate group-terminated prepolymer, the isocyanate group-terminated prepolymer comprises a reaction product of a polyisocyanate component and a polyol component, The polyisocyanate component comprises an isocyanurate derivative of pentamethylene diisocyanate; The isocyanurate derivative of the pentamethylene diisocyanate includes an isocyanurate-modified product of pentamethylene diisocyanate partially modified with an alcohol component, In the isocyanate group-terminated prepolymer, a first equivalent ratio (NCO / OH) of an isocyanate group of the polyisocyanate component to a hydroxyl group of the polyol component is 3.0 or more and 8.0 or less; a second equivalent ratio (NCO / OH) of the isocyanate groups of the pentamethylene diisocyanate to the hydroxyl groups of the alcohol component in the isocyanurate derivative of the pentamethylene diisocyanate is 60 or more and 600 or less.

2. The isocyanurate derivative of the pentamethylene diisocyanate includes a mononuclear isocyanurate of pentamethylene diisocyanate, The isocyanurate mononuclear compound of the pentamethylene diisocyanate is a derivative compound containing one isocyanurate group and three molecules of pentamethylene diisocyanate, In the chromatogram obtained by measuring the isocyanurate derivative of the pentamethylene diisocyanate by gel permeation chromatography, 2. The polyisocyanate composition according to claim 1, wherein the area ratio of the peak area corresponding to the isocyanurate mononuclear unit of the pentamethylene diisocyanate to the area of ​​all peaks is 40% or more.

3. The polyisocyanate composition according to claim 1 or 2, wherein the number average molecular weight of the polyol component is 200 or more and 1,000 or less.

4. The polyisocyanate composition according to any one of claims 1 to 3, wherein the average number of hydroxyl groups in the polyol component is 2.

5. Contains a base agent and a hardener, The base material contains a macropolyol, A coating agent, wherein the curing agent comprises the polyisocyanate composition according to any one of claims 1 to 4.

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