JP6153293B2 - Block polyisocyanate composition - Google Patents

Description

  The present invention relates to a block polyisocyanate composition which is substantially free of an organic solvent, has a low viscosity, and is excellent in compatibility with an active hydrogen compound as a main component.

  A polyisocyanate composed of an aliphatic diisocyanate or an alicyclic diisocyanate is known as a non-yellowing type, and is a curing agent excellent in weather resistance, chemical resistance and flexibility.

  Moreover, the block polyisocyanate in which the isocyanate group of the polyisocyanate is blocked with a heat dissociable blocking agent does not react at room temperature even when mixed with the active hydrogen compound as the main agent, and heat-dissociable block by heating. The agent dissociates, the isocyanate group is regenerated, and the reaction with the active hydrogen compound proceeds. For this reason, it becomes possible to store in the state which mixed the main ingredient and the hardening | curing agent beforehand. Thermally dissociable blocking agents that block isocyanate groups include oxime-based, alcohol-based, phenol-based, and amine-based agents, and various combinations of polyisocyanates and blocking agents have been proposed.

  Blocked polyisocyanates have the disadvantage of increasing the viscosity due to intermolecular hydrogen bonding due to urethane bonds or urea bonds generated by blocking. Therefore, it is usually used after diluting with an organic solvent and reducing the viscosity. In general, a polyurethane resin paint is diluted with an organic solvent or water, and therefore, a diluted polyurethane resin coating has an advantage that it is advantageous in handling.

  However, from the viewpoints of environmental protection and resource saving against air pollution, there is an urgent need to reduce the use of organic solvents. In addition, in applications where the film thickness is large, such as a casting agent and a sealing agent, there is a problem that volume shrinkage due to the residual organic solvent and generation of voids (bubbles) during heating become significant.

  Therefore, in recent years, a completely solvent-free polyurethane resin that does not use an organic solvent in the main ingredient and the curing agent as raw materials has attracted attention. Accordingly, several liquid blocked urethane prepolymers that can be used without solvent are known. For example, Patent Document 1 proposes a urethane prepolymer having a polycarbonate diol and an organic diisocyanate as raw material components and having an isocyanate group blocked at the terminal. Patent Document 2 proposes a urethane prepolymer obtained by reacting a lactone-modified diol with a polyfunctional isocyanate to form a block. In Patent Documents 1 and 2, since these blocked urethane prepolymers are liquid at room temperature, they are easy to handle, and the resin composition using them has high durability performance. Have been described.

JP 2006-70058 A JP 2002-121255 A

However, the blocked urethane prepolymer is difficult to handle depending on the application because of its high viscosity. In addition, these blocked urethane prepolymers generally have a lower isocyanate content in one molecule and a lower number of average isocyanate groups than isocyanate as a curing agent for coatings, so the crosslinking density is lowered, and in particular the number of hydroxyl groups in the molecule. When the active hydrogen compound with a small amount is the main agent, there is a disadvantage that the curability deteriorates.
Furthermore, when these blocked urethane prepolymers contain an organic solvent, the compatibility with the active hydrogen compound is good due to the solubility in the organic solvent, but the compatibility becomes worse due to the absence of solvent. There are many cases to do. Therefore, when a solvent-free blocked polyisocyanate is used as a curing agent, further improvement in viscosity, curability and compatibility is required.

  Accordingly, an object of the present invention is to provide a block polyisocyanate composition which is substantially free of an organic solvent, has a low viscosity, and is excellent in compatibility with an active hydrogen compound as a main component.

  The inventors of the present invention have made extensive studies to solve the above problems, and even when the block polyisocyanate composition having a specific structure does not substantially contain an organic solvent, it has a low viscosity and is an active hydrogen which is a main component. The present inventors have found that the compatibility with the compound is excellent and have completed the present invention.

That is, the present invention is as follows.
1. A block polyisocyanate composition obtained from a polyisocyanate obtained from at least one diisocyanate compound selected from aliphatic diisocyanate and alicyclic diisocyanate, and a monoalcohol having 1 to 20 carbon atoms, and a thermally dissociable blocking agent. A block polyisocyanate composition substantially free from an organic solvent, wherein the molar ratio of isocyanurate groups to allophanate groups in the polyisocyanate is 10/90 to 80/20.
2. 2. The block polyisocyanate composition according to item 1, wherein the heat dissociable blocking agent is at least one selected from oxime, acid amide, amine, active methylene and pyrazole compounds.
3. The block polyisocyanate composition according to item 1 or 2, wherein at least one diisocyanate compound selected from the aliphatic diisocyanate and the alicyclic diisocyanate is hexamethylene diisocyanate.
4). The curable composition containing the active hydrogen compound which does not contain an organic solvent substantially as a main ingredient, and the block polyisocyanate composition in any one of said 1-3.
5. The polyurethane curable composition containing the polyol compound which does not contain an organic solvent substantially as a main ingredient, and the block polyisocyanate composition in any one of the said 1-3.
6). The hardening composition obtained by heat-hardening the curable composition of the said 4th term.
7). A polyurethane curable composition obtained by heat-curing the polyurethane curable composition according to the above item 5.

  According to the present invention, it is suitable for use as a curing agent in a situation substantially free of a solvent, has a lower viscosity, excellent compatibility with the active hydrogen compound as the main agent, and good curability. Blocked polyisocyanate compositions can be provided.

The preferred embodiments of the present invention are described in detail below.
As a raw material of polyisocyanate which is a precursor of the block polyisocyanate composition of the present invention, at least one diisocyanate compound selected from aliphatic diisocyanate and alicyclic diisocyanate, and monoalcohol having 1 to 20 carbon atoms are included. Used.

  Examples of the aliphatic diisocyanate include butane diisocyanate, pentane diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), trimethylhexamethylene diisocyanate, and lysine diisocyanate. Among these, HDI is preferable from the viewpoint of industrial availability. The said aliphatic diisocyanate may be used independently and may use 2 or more types together.

  Examples of the alicyclic diisocyanate include isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexane diisocyanate. Among these, IPDI is preferable from the viewpoint of industrial availability. The said alicyclic diisocyanate may be used independently and may use 2 or more types together.

  One of the aliphatic diisocyanate and the alicyclic diisocyanate may be used alone, or two or more of the aliphatic diisocyanate and the alicyclic diisocyanate may be used in combination.

  A monoalcohol having 1 to 20 carbon atoms is used as a raw material for the polyisocyanate. The lower limit of the carbon number of the monoalcohol is preferably 2, more preferably 3, still more preferably 4, and particularly preferably 6. The upper limit is preferably 16, more preferably 12, and still more preferably 9. Only one type of monoalcohol may be used, or two or more types may be mixed and used. The monoalcohol may contain an ether group, an ester group, or a carbonyl group in the molecule, but a monoalcohol consisting only of a saturated hydrocarbon group is preferred. Furthermore, a monoalcohol having a branch is more preferable. Examples of such monoalcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2 -Hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,5,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol , Methylcyclohexanol, trimethylcyclohexanol and the like. Among these, isobutanol, 1-butanol, isoamyl alcohol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, 3, 5,5-Trimethyl-1-cyclohexanol is more preferable because of its excellent compatibility with active hydrogen compounds.

The polyisocyanate which is a precursor of the block polyisocyanate composition of the present invention contains an isocyanurate group and an allophanate group in the molecule. An isocyanurate group is a structure formed from three isocyanate groups,


It is shown by the structure of

The allophanate group is formed from a hydroxyl group and an isocyanate group of monoalcohol,


It is shown by the structure of

  The molar ratio of isocyanurate groups to allophanate groups in the polyisocyanate is 10/90 to 80/20. This molar ratio is preferably 20/80 to 80/20, more preferably 30/70 to 70/30.

  As a method for producing a polyisocyanate containing an isocyanurate group and an allophanate group, a specific mole of an isocyanurate group and an allophanate group is selected from at least one diisocyanate compound selected from the above aliphatic diisocyanates and alicyclic diisocyanates. A method of producing and mixing a plurality of types of polyisocyanate compounds contained in a ratio, and a method of producing polyisocyanates having an isocyanurate group and an allophanate group all together from the diisocyanate compound.

The following three methods are mentioned as a method for producing the polyisocyanate.
(I) A method of obtaining a polyisocyanate by subjecting a monoalcohol and a diisocyanate to a urethanization reaction, and thereafter or simultaneously carrying out an allophanatization reaction and an isocyanurate reaction.
(II) A polyalcohol having an isocyanurate group obtained by subjecting a monoalcohol and a diisocyanate to a urethanization reaction, and thereafter or simultaneously carrying out an allophanate reaction, and the resulting polyisocyanate having an allophanate group and an isocyanurate reaction of the diisocyanate. A method of obtaining polyisocyanate by mixing with isocyanate.
(III) Urethane reaction of monoalcohol and diisocyanate, and then or allophanate reaction, polyisocyanate containing allophanate group obtained, urethanation reaction of monoalcohol and diisocyanate, and then allophanate And isocyanurate-forming reaction, and the resulting polyisocyanate is mixed with the polyisocyanate having an allophanate group and an isocyanurate group.

  Since the method (I) can be manufactured by a one-step process, it has a feature of high production efficiency. In the methods (II) and (III), a polyisocyanate having an isocyanurate structure or a polyisocyanate having an isocyanurate structure and an allophanate structure and a polyisocyanate having an allophanate group can be mixed in an arbitrary ratio. Therefore, there is a feature that the physical properties of the resulting polyisocyanate can be easily adjusted.

  It is produced so that the molar ratio of isocyanurate groups to allophanate groups in the polyisocyanate is in the range of 10/90 to 80/20, preferably 20/80 to 80/20, more preferably 30/70 to 70/30. Any method may be used.

  The reaction temperature of the urethanization reaction is preferably 20 to 200 ° C, more preferably 40 to 150 ° C, and still more preferably 60 to 120 ° C. The reaction time is preferably 10 minutes to 24 hours, more preferably 15 minutes to 15 hours, and even more preferably 20 minutes to 10 hours. The reaction is fast at 20 ° C. or higher, side reactions such as uretdione formation are suppressed at 200 ° C. or lower, and coloring is also suppressed. If the time is 10 minutes or more, the reaction can be completed. If the time is 24 hours or less, there is no problem in production efficiency, and side reactions are also suppressed. The urethanization reaction can be carried out without a catalyst or in the presence of a tin-based or amine-based catalyst.

  The allophanatization reaction is preferably performed at a temperature of 20 to 200 ° C. More preferably, it is 40-180 degreeC, More preferably, it is 60-160 degreeC. Particularly preferred is 90 to 150 ° C, and most preferred is 110 to 150 ° C. Above 20 ° C., the amount of allophanatization catalyst decreases and the time required to complete the reaction is short. At 200 ° C. or lower, side reactions such as uretdione formation are suppressed, and coloring of the reaction product is suppressed.

  The reaction time of the allophanatization reaction is preferably 10 minutes to 24 hours, more preferably 15 minutes to 12 hours, still more preferably 20 minutes to 8 hours, and particularly preferably 20 minutes to 6 hours. If the reaction time is 10 minutes or more, the reaction can be controlled, and if it is within 24 hours, the production efficiency is sufficient. In addition, when reaction temperature exceeds 130 degreeC, since uretdione may produce | generate as a side reaction, Preferably reaction time is less than 8 hours, More preferably, it is less than 6 hours, More preferably, it is less than 4 hours.

  The isocyanuration reaction, or allophanatization and isocyanuration reaction is preferably performed at a temperature of 20 to 180 ° C. More preferably, it is 30-160 degreeC, More preferably, it is 40-140 degreeC. Particularly preferred is 60 to 130 ° C, and most preferred is 80 to 110 ° C. At 20 ° C. or higher, the amount of the catalyst can be reduced, and side reactions such as nylon reaction are less likely to occur. Further, at 180 ° C. or lower, side reactions such as uretdione formation are suppressed, and coloring of the reaction product is suppressed.

  The reaction time of the isocyanuration reaction, or allophanation and isocyanuration reaction is preferably 10 minutes to 24 hours, more preferably 15 minutes to 12 hours, still more preferably 20 minutes to 8 hours, particularly preferably 20 minutes to 6 hours. If the reaction time is 10 minutes or more, the reaction can be controlled, and if it is within 24 hours, the production efficiency is sufficient.

  When employing the method (I), it is preferable to use a catalyst for the allophanate reaction and isocyanurate reaction, and the molar ratio of the isocyanurate group / allophanate group of the polyisocyanate to be produced is particularly 10/90 to 80/20. It is preferable to select a catalyst that can be Examples of such a catalyst include tetraalkylammonium, hydroxyalkylammonium carboxylates, hydroxides, aminosilyl group-containing compounds, and the like, or mixtures thereof.

  When employing the method (II) or (III) to produce a polyisocyanate having an allophanate group, it is preferable to use a catalyst for the allophanate reaction. In particular, the catalyst capable of increasing the selectivity of the allophanate group, that is, the ratio of isocyanurate group / allophanate group of the polyisocyanate to be produced is preferably 0/100 to 30/70, more preferably 0/100 to 20/80, It is more preferable to select a catalyst with a value of 0/100 to 10/90. Examples of such catalysts include lead, zinc, bismuth, tin, zirconium, zirconyl carboxylates, etc., zinc, zirconium, tin alkoxides, or mixtures thereof.

  When the method (II) is employed to produce a polyisocyanate containing an isocyanurate group, it is preferable to use a catalyst for the isocyanurate formation reaction. Examples of the isocyanurate-forming catalyst include tetraalkylammonium, hydroxyalkylammonium, carboxylic acid alkali metal salts, hydroxides, aminosilyl group-containing compounds, and the like, or mixtures thereof.

  When the method (III) is employed to produce a polyisocyanate containing an allophanate group and an isocyanurate group, it is preferable to use a catalyst for the allophanate reaction and the isocyanurate reaction. Examples of the allophanatization and isocyanuration catalysts include tetraalkylammonium, hydroxyalkylammonium, alkali metal salts of carboxylic acids, hydroxides, aminosilyl group-containing compounds, and the like, or mixtures thereof.

  The allophanate catalyst, isocyanurate catalyst, allophanate and isocyanurate catalyst are preferably 0.001 to 2.0% by mass, more preferably 0.01 to 0.5%, based on the total weight of the reaction solution. Used in an amount of mass%. The effect of the catalyst can be sufficiently exerted at 0.001% by mass or more. The reaction is easily controlled at 2% by mass or less.

  In the production of the polyisocyanate, the method for adding the allophanate catalyst, isocyanurate catalyst, allophanate catalyst and isocyanurate catalyst is not limited. For example, it may be added before the production of a compound containing a urethane group, that is, prior to the urethanization reaction of an organic compound having a diisocyanate and a hydroxyl group, or during the urethanization reaction of an organic compound having a diisocyanate and a hydroxyl group. It may also be added after the production of the urethane group-containing compound. In addition, as a method of addition, a required amount of the allophanate catalyst, isocyanurate catalyst, allophanate catalyst and isocyanurate catalyst may be added all at once, or may be added in several portions. Or the method of adding continuously at a fixed addition rate is also employable.

  The urethanization reaction and allophanate reaction can be allowed to proceed without solvent. In addition, in these reactions, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl ethyl ketone, aromatic solvents such as toluene, xylene, and diethylbenzene, dialkyl polyalkylene glycol ethers, etc. Organic solvents that are not reactive with isocyanate groups and mixtures thereof can be used as the solvent.

  The process of urethanization reaction, allophanate reaction, isocyanurate reaction, allophanate reaction and isocyanurate reaction in the production of the above polyisocyanate is determined by measuring the NCO group content of the reaction solution or measuring the refractive index. Can track.

  The allophanate reaction, isocyanurate reaction, allophanate reaction and isocyanurate reaction can be stopped by cooling to room temperature or adding a reaction terminator. When using a catalyst, it is preferable to add a reaction terminator because side reactions can be suppressed. The amount of addition of the reaction terminator is preferably 0.25 to 20 times the molar amount, more preferably 0.5 to 16 times the molar amount, still more preferably 1.0 to 12 times the molar amount relative to the catalyst. Amount. It can be completely deactivated at a molar amount of 0.25 times or more. Storage stability is improved at a molar amount of 20 times or less.

  Any reaction terminator may be used as long as it deactivates the catalyst. Examples of reaction terminators include phosphoric acid, pyrophosphoric acid and other phosphoric acid compounds, phosphoric acid, monoalkyl or dialkyl esters such as pyrophosphoric acid, halogenated acetic acid such as monochloroacetic acid, benzoyl chloride, sulfonic acid ester, Examples include sulfuric acid, sulfuric ester, ion exchange resin, chelating agent and the like. From an industrial viewpoint, phosphoric acid, pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, and phosphoric acid monoalkyl ester and phosphoric acid dialkyl ester are preferred because they hardly corrode stainless steel. Examples of phosphoric acid monoesters and phosphoric acid diesters include phosphoric acid monoethyl ester, phosphoric acid diethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, phosphoric acid mono (2-ethylhexyl) ester and phosphoric acid di (2 -Ethylhexyl) ester, phosphoric acid monodecyl ester, phosphoric acid didecyl ester, phosphoric acid monolauryl ester, phosphoric acid dilauryl ester, phosphoric acid monotridecyl ester, phosphoric acid ditridecyl ester, phosphoric acid monooleyl ester, phosphoric acid Dioleyl ester, phosphoric acid monotetradecyl ester, phosphoric acid ditetradecyl ester, phosphoric acid monohexadecyl ester, phosphoric acid dihexadecyl ester, phosphoric acid monooctadecyl ester, phosphoric acid dioctadecyl ester, etc., or a mixture thereof But It is below.

  It is also possible to use an adsorbent such as silica gel or activated carbon as a stopper. In this case, an addition amount of 0.05 to 10% by mass is preferable with respect to the diisocyanate used in the reaction.

  After completion of the reaction, unreacted diisocyanate and solvent may be separated from the polyisocyanate. In view of safety, it is preferable to separate unreacted diisocyanate. Examples of a method for separating unreacted diisocyanate and solvent include a thin film distillation method and a solvent extraction method.

  The molar ratio (a) / (b) between the isocyanurate group (a) and the allophanate group (b) in the polyisocyanate can be determined by 1H-NMR. An example of a method for measuring a polyisocyanate composition using HDI as a raw material by 1H-NMR is shown below.

  Measurement method example of 1H-NMR: Polyisocyanate is dissolved in deuterium chloroform at a concentration of 10% by mass (0.03% by mass of tetramethylsilane is added to polyisocyanate). As a chemical shift standard, a hydrogen signal of tetramethylsilane was set to 0 ppm. Measured by 1H-NMR, signal of hydrogen atom bonded to nitrogen atom of allophanate group near 8.5 ppm (1 mol hydrogen atom per 1 mol of allophanate group) and isocyanurate of isocyanurate group around 3.8 ppm The signal area ratio of the hydrogen atom of the methylene group adjacent to the nitrogen atom of the ring (6 mol of hydrogen atom per mol of isocyanurate group) is measured. The molar ratio (a) / (b) of the isocyanurate group (a) to the allophanate group (b) in this polyisocyanate is (a) / (b) = (signal area around 3.8 ppm / 6) / (8 (Signal area around 5 ppm).

  The isocyanate group content (hereinafter referred to as NCO group content) of the polyisocyanate is preferably 10 to 25% by mass and more preferably 13 to 22% by mass in a state that substantially does not contain a solvent or diisocyanate. The NCO group content can be determined, for example, by reacting an isocyanate group of polyisocyanate with an excess of amine (such as dibutylamine) and back titrating the remaining amine with an acid such as hydrochloric acid.

The viscosity of the polyisocyanate at 25 ° C. is preferably 150 to 800 mPa · s in a state in which substantially no solvent or diisocyanate is contained. The viscosity was measured with an E-type viscometer (manufactured by Tokimec Co., Ltd.), and a standard rotor (1 ° 34 ′ × R24) was used as the rotor. The number of rotations is as follows.
100r. p. m. (If less than 128 mPa · s)
50r. p. m. (In the case of 128 mPa · s to 256 mPa · s)
20r. p. m. (In the case of 256 mPa · s to 640 mPa · s)
10r. p. m. (In the case of 640 mPa · s to 1280 mPa · s)
5r. p. m. (In the case of 1280 mPa · s to 2560 mPa · s)

Although the number average molecular weight Mn of the said polyisocyanate does not have a restriction | limiting in particular, Preferably it is 450-1200, More preferably, it is 500-1000. Mn was calculated by gel permeation chromatograph (hereinafter referred to as GPC) measurement, and the area ratio of each peak of GPC was defined as mass%.
Equipment: Tosoh Corporation HLC-802A
Column: Tosoh Corporation G1000HXL × 1 G2000HXL × 1 G3000HXL × 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

The number average functional group number fn of the polyisocyanate is not particularly limited, but is preferably 2.20 to 4.00, more preferably 2.30 to 3.50 from the viewpoints of curability and low viscosity. fn can be obtained by the following equation.
fn = Mn × NCO group content / 4200

  The block polyisocyanate composition in the present invention can be produced by reacting the isocyanate group of the polyisocyanate with a heat dissociable blocking agent to form a block. Here, “thermal dissociation” means that the blocking agent bonded to the isocyanate group is dissociated by heating. The temperature required for dissociation varies depending on the structure of the blocking agent, but is, for example, 40 ° C to 300 ° C.

  Examples of the heat dissociable blocking agent include oxime, alcohol, acid amide, acid imide, phenol, amine, active methylene, imidazole and pyrazole compounds.

  Examples of oximes include formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime, and alcohols include methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1- Examples of acid amides such as hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, etc. include acetanilide, acetic acid amide, ε-caprolactam, δ-valerocactam, γ-butyrolactam, etc. Examples of phenolic compounds such as imide and maleic imide include phenol, cresol, ethylphenol, butylphenol, nonylphenol, dinonylphenol, styrenated phenol, and hydroxybenzoic acid ester. As the amine system, diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, etc., as the active methylene system, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, Examples of the imidazole series such as acetylacetone include imidazole and 2-methylimidazole, and examples of the pyrazole series include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole. Among these, from the viewpoints of availability, viscosity of the produced block polyisocyanate composition, reaction temperature, and reaction time, oxime-based, acid amide-based, amine-based, active methylene-based, and pyrazole-based compounds are preferable, and methyl ethyl ketoxime, ε -Caprolactam, diethyl malonate, ethyl acetoacetate, 3,5-dimethylpyrazole are more preferred.

  One kind of the heat dissociable blocking agent may be used, or two or more kinds may be used in a desired ratio. Moreover, although it may block completely or partially by a well-known method, it is preferable to block all. When all the isocyanate groups are blocked, the (number of moles of thermally dissociable blocking agent) / (number of moles of isocyanate groups in the polyisocyanate composition) is preferably 1.0 to 1.5. In that case, excess or unreacted thermally dissociable blocking agent remains in the blocked polyisocyanate composition. The blocking reaction may be performed in the same manner as in the polyisocyanate without using a solvent or, if necessary, an organic solvent that does not have reactivity with an isocyanate group may be used, and the organic solvent may be separated later. .

  Although the reaction temperature for blocking can be set to -20 to 150 ° C, it is preferably 0 to 100 ° C from the viewpoint of reaction rate and side reaction.

  The block polyisocyanate composition in the present invention contains substantially no organic solvent. “Substantially free” means that the organic solvent content in the block polyisocyanate composition is 10% by mass or less. Further, from the viewpoint of generation of voids due to curing with the active hydrogen compound as the main agent, it is preferably 9% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less, and even more preferably 3% by mass or less. The mass% or less is even more preferable.

  Examples of the organic solvent to be contained include aliphatic hydrocarbon solvents such as hexane, heptane and octane, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, and ethyl lactate, aromatic solvents such as toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenyl glycol, chlorobenzene, ethylene glycol mono Glycol solvents such as ethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, diethyl ether Ether solvents such as tetrahydrofuran and dioxane, halogenated hydrocarbon solvents such as dichloromethane, 1,2-dichloroethane and chloroform, pyrrolidone solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N An amide solvent such as dimethylformamide, a sulfoxide solvent such as dimethyl sulfoxide, a lactone solvent such as γ-butyrolactone, an amine solvent such as morpholine, and a mixture thereof.

  The viscosity at 25 ° C. of the block polyisocyanate composition in the present invention is preferably 10,000 to 1,000,000 mPa · s from the viewpoints of handleability and miscibility with the active hydrogen compound as the main agent. To 600,000 mPa · s is more preferred, and 10,000 to 300,000 mPa · s is particularly preferred. For the measurement of viscosity, a rheometer (RS-1 manufactured by HAAKE) was used in addition to the E-type viscometer. The rotor was selected according to the viscosity.

  Further, the value obtained by dividing the viscosity of the block polyisocyanate composition by the viscosity of the polyisocyanate used as a raw material (thickening ratio) is preferably 5 to 10,000 times at 25 ° C. from the viewpoint of handleability of the composition. 5 to 7,000 times is more preferable.

  The curable composition is formed by mixing the block polyisocyanate composition in the present invention with an active hydrogen compound (polyvalent active hydrogen compound) substantially free of an organic solvent as a main component. When this curable composition is heated, the thermally dissociable blocking agent bonded to the isocyanate group is dissociated, and this isocyanate group reacts with active hydrogen in the active hydrogen compound, whereby a cured composition (cured product) is obtained. It can be.

  The active hydrogen compound is a compound in which two or more active hydrogens are bonded in the molecule. Examples of active hydrogen compounds include polyols, polyamines, polythiols, and the like, but many use polyols.

  Examples of the polyol include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, and epoxy resin.

  As the polyester polyol, for example, a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, or a mixture thereof, Polyester polyol obtained by a condensation reaction with a single or mixture of polyhydric alcohols selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, and the like, and for example, polyhydric alcohols were used. and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone.

  Acrylic polyol is obtained by copolymerizing an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof and another ethylenically unsaturated bond-containing monomer copolymerizable therewith. Is obtained.

  Examples of the ethylenically unsaturated bond-containing monomer having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. It is done. Preferred are hydroxyethyl acrylate and hydroxyethyl methacrylate.

  Other ethylenically unsaturated bond-containing monomers copolymerizable with the above monomers include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, Acrylic acid esters such as acrylic acid-n-hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate Methacrylic acid-n-butyl, isobutyl methacrylate, methacrylic acid-n-hexyl, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate, etc. Acid esters, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, maleimide, etc. Unsaturated amides and vinyl monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate, vinyl trimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) acryloxypropyltri Examples thereof include vinyl monomers having a hydrolyzable silyl group such as methoxysilane.

  As the polyether polyol, for example, a strong basic catalyst such as a hydroxide such as lithium, sodium or potassium, an alcoholate or an alkylamine is used, and a polyhydric hydroxy compound is used alone or as a mixture, with ethylene oxide, propylene oxide or butylene. Polyether polyols obtained by adding an alkylene oxide such as oxide, cyclohexene oxide, and styrene oxide alone or in a mixture, polyether polyols obtained by reacting an alkylene oxide with a polyfunctional compound such as ethylenediamine, and So-called polymer polyols obtained by polymerizing acrylamide or the like using these polyethers as a medium are included.

As the polyvalent hydroxy compound,
(1) Diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc .;
(2) Sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, and rhamnitol;
(3) monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribosese;
(4) Disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose;
(5) Trisaccharides such as raffinose, gentianose, meletitose;
(6) tetrasaccharides such as stachyose;
Etc.

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

  The fluorine polyol is a polyol containing fluorine in the molecule. For example, fluoroolefin, cyclovinyl ether, hydroxyalkyl vinyl ether, vinyl monocarboxylate disclosed in JP-A-57-34107 and JP-A-61-275111. There are copolymers such as esters.

  Polycarbonate polyol is obtained by polycondensation of a low molecular carbonate compound such as dialkyl carbonate such as dimethyl carbonate, alkylene carbonate such as ethylene carbonate, diaryl carbonate such as diphenyl carbonate, and the low molecular polyol used in the above-mentioned polyester polyol. Can be mentioned.

  As epoxy resin, novolak type, glycidyl ether type, glycol ether type, epoxy type of aliphatic unsaturated compound, epoxy type fatty acid ester, polycarboxylic acid ester type, aminoglycidyl type, β-methyl epichloro type, cyclic oxirane type, Halogen type, resorcin type and the like can be mentioned.

  The hydroxyl value of the polyol is preferably 10 to 300 mgKOH / g per resin from the viewpoint of crosslink density and mechanical properties of the cured resin.

  In the curable composition of the present invention, the equivalent ratio of blocked isocyanate groups to active hydrogen groups is usually set to 10: 1 to 1:10.

  Other curing agents such as melamine curing agents and epoxy curing agents can be used in combination. Typical examples of the melamine curing agent include a fully alkyl etherified melamine resin, a methylol group type melamine resin, and an imino group type melamine resin partially having an imino group.

  When a melamine curing agent is used in combination, the addition of an acidic compound is effective. Specific examples of the acidic compound include carboxylic acid, sulfonic acid, acidic phosphate ester, and phosphite ester.

  Typical examples of the carboxylic acid include acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid. Examples of the sulfonic acid include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenedisulfonic acid. Examples of acidic phosphate esters include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, and monooctyl phosphate. Examples of the phosphite include diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite and monolauryl phosphite.

  In addition, depending on the purpose and application, the block polyisocyanate composition and the polyol, such as a curing accelerating catalyst, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a leveling agent, a plasticizer, a surfactant, etc. Various additives can be mixed and used.

  Curing accelerating catalysts include dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, tin compounds such as bis (2-ethylhexanoic acid) tin, zinc 2-ethylhexanoate, zinc naphthenate Zinc compounds such as titanium compounds such as titanium 2-ethylhexanoate and titanium diisopropoxybis (ethylacetonate), cobalt compounds such as cobalt 2-ethylhexanoate and cobalt naphthenate, bismuth 2-ethylhexanoate and naphthene Examples thereof include bismuth compounds such as bismuth acid, zirconium tetraacetylacetonate, zirconium compounds such as zirconyl 2-ethylhexanoate and zirconyl naphthenate, and amine compounds. Antioxidants include hindered phenols, phosphorus compounds, sulfur compounds, and the like. Examples of the ultraviolet absorber include benzotriazole-based, triazine-based, and benzophenone-based compounds. Examples of the light stabilizer include hindered amines, benzotriazoles, triazines, benzophenones, and benzoates. Examples of the pigment include titanium oxide, carbon black, indigo, pearl mica, and aluminum. A silicone oil etc. are mentioned as a leveling agent. Examples of the plasticizer include phthalic acid esters, phosphoric acid type, and polyester type. Examples of the surfactant include known anionic surfactants, cationic surfactants, and amphoteric surfactants.

The present invention will be described in more detail with reference to examples and comparative examples.
In the following, “part” and “%” indicating the amount or ratio of a product mean values based on mass unless otherwise specified.

Below, the synthesis example of a block polyisocyanate composition is shown.
The molar ratio (a) / (b) between the isocyanurate group (a) and the allophanate group (b) of the polyisocyanate is as follows using 1H-NMR (FT-NMR DPX-400 manufactured by Bruker): Measured. Polyisocyanate is dissolved in deuterium chloroform at a concentration of 10% by mass (0.03% by mass of tetramethylsilane is added to polyisocyanate), and the chemical shift criterion is that the hydrogen signal of tetramethylsilane is 0 ppm, and 1H -Measured by NMR, signal of hydrogen atom bonded to nitrogen atom of allophanate group near 8.5 ppm (1 mol hydrogen atom per 1 mol of allophanate group) and isocyanurate ring of isocyanurate group around 3.8 ppm The area ratio of the signal of the hydrogen atom of the methylene group adjacent to the nitrogen atom (6 mol of hydrogen atom per mol of isocyanurate group) was determined, and isocyanurate group / allophanate group = (signal area around 3.8 ppm / 6) ) / (Signal area around 8.5 ppm) Calculated isocyanurate groups in chromatography preparative and (a) the molar ratio of allophanate groups and (b) (a) / (b).

  The NCO group content of the starting polyisocyanate was determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate group with an excess of 2N amine.

The viscosity of the polyisocyanate as a raw material was measured with an E-type viscometer (manufactured by Tokimec Co., Ltd.), and a standard rotor (1 ° 34 ′ × R24) was used as the rotor. The number of rotations is as follows.
100r. p. m. (If less than 128 mPa · s)
50r. p. m. (In the case of 128 mPa · s to 256 mPa · s)
20r. p. m. (In the case of 256 mPa · s to 640 mPa · s)
10r. p. m. (In the case of 640 mPa · s to 1280 mPa · s)
5r. p. m. (In the case of 1280 mPa · s to 2560 mPa · s)

  The viscosity of the block polyisocyanate composition was measured at 25 ° C. using a rheometer (RS-1 manufactured by HAAKE). The rotor used was 2 ° × R10.

[Synthesis Example 1]
(Synthesis of polyisocyanate A-1)
The inside of a four-necked flask equipped with a stirrer, a thermometer, and a condenser tube was replaced with nitrogen. To this four-necked flask, 1000 g of HDI and 30 g of 2-ethylhexanol were charged and stirred at 80 ° C. for 1 hour to carry out a urethanization reaction. As an allophanatization and isocyanurate formation catalyst, 0.36 g of a solid content 10% n-butanol solution of tetramethylammonium caprate was added. After further stirring for 3 hours, 0.58 g of a 85% solid solution of phosphoric acid was added to stop the reaction. After filtration of the reaction solution, polyisocyanate A-1 was obtained by removing unreacted HDI at 160 ° C. (27 Pa) for the first time and 150 ° C. (13 Pa) for the second time using a falling film distillation apparatus. The obtained polyisocyanate A-1 was a pale yellow transparent liquid, the yield was 300 g, the viscosity at 25 ° C. was 450 mPa · s, and the NCO group content was 20.6%. When 1H-NMR was measured, the isocyanurate group / allophanate group molar ratio was 65/35.

[Synthesis Example 2]
(Synthesis of polyisocyanate A-2)
In the same apparatus as in Synthesis Example 1, 1000 g of HDI and 30 g of 2-ethylhexanol were charged, and urethanization reaction was performed at 90 ° C. for 1 hour with stirring. At 90 ° C., 0.6 g of a solid content 5% isobutanol solution of tetramethylammonium caprate was added as an allophanatization and isocyanuration catalyst. After further stirring for 2 hours, 0.06 g of 85% aqueous phosphoric acid solution was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1. The obtained polyisocyanate A-2 was a transparent liquid, the yield was 210 g, the viscosity at 25 ° C. was 340 mPa · s, and the NCO group content was 20.3%. When 1H-NMR was measured, the isocyanurate group / allophanate group molar ratio was 50/50.

[Synthesis Example 3]
(Synthesis of polyisocyanate A-3)
In the same apparatus as in Synthesis Example 1, 1000 g of HDI and 50 g of isobutanol were charged and stirred at 90 ° C. for 1 hour to carry out a urethanization reaction. As an allophanatization and isocyanuration catalyst, 0.53 g of a solid content 10% n-butanol solution of tetramethylammonium caprate was added. After further stirring for 3 hours, 0.10 g of a 85% solid solution of phosphoric acid was added to stop the reaction. After filtration of the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A-3. The obtained polyisocyanate A-3 was a pale yellow transparent liquid, the yield was 440 g, the viscosity at 25 ° C. was 450 mPa · s, and the NCO group content was 19.6%. When 1H-NMR was measured, the isocyanurate group / allophanate group molar ratio was 40/60.

[Synthesis Example 4]
(Synthesis of polyisocyanate A-4)
In the same apparatus as in Synthesis Example 1, 500 g of HDI was charged, and 0.08 g of tetramethylammonium capryate was added with stirring at 60 ° C. The reaction was allowed to proceed at 60 ° C., and after 4 hours, when the conversion rate to polyisocyanate reached 20% by measuring the isocyanate group content and refractive index of the reaction solution, 0.2 g of phosphoric acid was added to react. Stopped. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A-4. The obtained polyisocyanate A-4 was a pale yellow transparent liquid, the yield was 102 g, the viscosity at 25 ° C. was 1400 mPa · s, and the NCO group content was 23.4%. When 1H-NMR was measured, the isocyanurate group / allophanate group molar ratio was 100/0.

[Synthesis Example 5]
(Synthesis of polyisocyanate A-5)
In the same apparatus as in Synthesis Example 1, 561.9 g of HDI and 38.1 g of isobutanol were charged, and a urethanization reaction was performed at 90 ° C. for 60 minutes with stirring. After raising the temperature to 120 ° C., 0.28 g of 20% mineral spirit solution of zirconyl 2-ethylhexanoate in solid content as an allophanatization catalyst was added. Further, after stirring for 60 minutes, 0.097 g of 85% solid solution of phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A-5. The obtained polyisocyanate A-5 was a pale yellow transparent liquid, the yield was 203 g, the viscosity at 25 ° C. was 130 mPa · s, and the NCO group content was 18.8%. When 1H-NMR was measured, the molar ratio of isocyanurate group / allophanate group was 3/97.

[Synthesis Example 6]
(Synthesis of polyisocyanate A-6)
In an apparatus similar to Synthesis 1, 400 g of HDI and 160 g of PTG2000 (product name, polytetramethylene glycol manufactured by Hodogaya Chemical Co., Ltd., number average molecular weight: 2,000) were charged, and a urethane reaction was performed at 100 ° C. for 1 hour with stirring. . After the temperature was lowered to 60 ° C., 0.8 g of tetramethylammonium capryate was gradually added as a catalyst, and an isocyanuration reaction was performed for 4 hours. The reaction was stopped by adding 0.6 g of 89% phosphoric acid. The temperature was further raised to 90 ° C., and stirring was continued for 1 hour. After cooling and filtering the reaction solution, unreacted HDI was removed using a thin-film distiller. The obtained polyisocyanate A-6 was a pale yellow transparent liquid, the viscosity at 25 ° C. was 5,500 mPa · s, and the NCO group content was 10.5%.

[Synthesis Example 7]
(Synthesis of Block Polyisocyanate Compositions B-1 to B3 and 7 to 9 by Blocking Reaction of Polyisocyanate A-1 to 6)
In the same apparatus as in Synthesis Example 1, the polyisocyanate A-1 to 6 obtained in Synthesis Examples 1 to 6 were charged and heated to 40 ° C., and methyl ethyl ketoxime was added to the NCO-containing molar amount of the polyisocyanate by 1 .05-fold molar amount was gradually added. After all was added, warmed to 60 ° C. and stirred for 2 hours. After confirming that absorption due to isocyanate disappeared by FT-IR, stirring was stopped and a block polyisocyanate composition was obtained. Table 1 shows the viscosity (mPa · s), effective NCO content (mass%) and organic solvent content (mass%) at 25 ° C. of the block polyisocyanate composition.

[Synthesis Example 8]
(Synthesis of Block Polyisocyanate Composition B-4 by Blocking Reaction of Polyisocyanate A-3)
In the same apparatus as in Synthesis Example 1, the polyisocyanate A-3 synthesized in Synthesis Example 3 was charged and heated to 80 ° C., and 3,5-dimethylpyrazole was added in an amount of 1. A 05-fold molar amount was gradually added. After all was added, the mixture was further stirred for 2 hours. After confirming that absorption due to isocyanate disappeared by FT-IR, stirring was stopped and a block polyisocyanate composition was obtained. Table 1 shows the viscosity (mPa · s), effective NCO content (mass%) and organic solvent content (mass%) at 25 ° C. of the block polyisocyanate composition.

[Synthesis Example 9]
(Synthesis of Block Polyisocyanate Composition B-5 by Blocking Reaction of Polyisocyanate A-3)
In the same apparatus as in Synthesis Example 1, the polyisocyanate A-3 synthesized in Synthesis Example 3 was charged and heated to 60 ° C., and ε-caprolactam was 1.05 times mol of the NCO-containing molar amount of the polyisocyanate. The amount was added gradually. After all addition, warmed to 90 ° C. and stirred for 6 hours. After confirming that absorption due to isocyanate disappeared by FT-IR, stirring was stopped and a block polyisocyanate composition was obtained. Table 1 shows the viscosity (mPa · s), effective NCO content (mass%) and organic solvent content (mass%) at 25 ° C. of the block polyisocyanate composition.

[Synthesis Example 10]
(Synthesis of Block Polyisocyanate Composition B-6 by Blocking Reaction of Polyisocyanate A-3)
In a device similar to Synthesis Example 1, 100 parts of Polyisocyanate A-3 synthesized in Synthesis Example 3, 57 parts of diethyl malonate, and 12 parts of ethyl acetoacetate were charged, and 0.7 part of 28% sodium methylate solution was added to room temperature. And reacted at 60 ° C. for 6 hours. Thereafter, 4 parts of 1-butanol was added and stirring was continued at that temperature for 1 hour. Thereto was added 0.8 part of dibutyl phosphate to obtain a block polyisocyanate composition. Table 1 shows the viscosity (mPa · s), effective NCO content (mass%) and organic solvent content (mass%) at 25 ° C. of the block polyisocyanate composition.

[Examples 1 to 6, Comparative Examples 1 and 2]
(Compatibility test with polyol)
The blocked polyisocyanate compositions B-1 to 9 obtained in Synthesis Examples 7 to 10 and the following polyols are blended so that the equivalent ratio of blocked isocyanate groups / hydroxyl groups is 1.0, The compatibility of the blended solution when allowed to stand at 23 ° C. was visually observed. The compounded solution was evaluated as “◯” when it was transparent and compatible, and “X” when it was cloudy or separated. The obtained results are shown in Table 1.
The polyols used in the compatibility test are as follows.
Polyol 1: Polycarbonate diol manufactured by Asahi Kasei Chemicals, Duranol (registered trademark) T5652, hydroxyl value 56 mgKOH / g, number average molecular weight 2,000
Polyol 2: Castor oil-based polyol TLM manufactured by Toyokuni Oil Co., Ltd., hydroxyl value 161 mgKOH / g, number average molecular weight 950

(Curing test)
The blocked polyisocyanate compositions B-1 to 9 obtained in Synthesis Examples 7 to 10 and the polyol 1 are blended so that the equivalent ratio of blocked isocyanate groups / hydroxyl groups is 1.0, A coating film was formed on an exclusive coated plate (made of polypropylene) with an applicator. After baking for 30 minutes in the oven at the temperature shown in Table 1, the coating film was peeled off, and the remaining film ratio (gel fraction) when immersed in acetone at 23 ° C. for 24 hours was measured. A gel fraction of 85% or more was rated as ◯, and a gel fraction of less than 85% as x. The obtained results are shown in Table 1.

(Void observation in cured product)
The blocked polyisocyanate compositions B-1 to 9 obtained in Synthesis Examples 7 to 10 and the polyol 1 are blended so that the equivalent ratio of blocked isocyanate groups / hydroxyl groups is 1.0, It was poured into an aluminum dish having a diameter of 50 mm and a height of 10 mm to a height of 8 mm. After heating for 30 minutes in an oven maintained at 160 ° C., the cured product was taken out and the cross section was observed. In the case where voids of 100 μm or more were not observed, the mark was “◯”. The obtained results are shown in Table 1.

[Examples 7 and 8, Reference Examples 1 and 2 , Comparative Examples 4 to 6]
Block polyisocyanate compositions B-3 and 7 were synthesized by the method described in Synthesis Example 7, and butyl acetate was added as an organic solvent so that the organic solvent content shown in Table 2 was obtained.
As in Examples 1 to 6 and Comparative Examples 1 to 3, a compatibility test with a polyol, a curability test, and void observation in the cured product were performed. The obtained results are shown in Table 2.

  Since the block polyisocyanate composition of the present invention has a specific isocyanurate group to allophanate group ratio, it is compatible with an active hydrogen compound such as a polyol even though it contains substantially no organic solvent. , And low viscosity and high curability. Therefore, it exhibits excellent performance as a paint, adhesive, pressure-sensitive adhesive, ink, sealing agent, casting agent, sealant, surface modifier, coating agent and the like.

Claims (7)

A block polyisocyanate composition obtained from a polyisocyanate obtained from at least one diisocyanate compound selected from aliphatic diisocyanate and alicyclic diisocyanate, and a monoalcohol having 1 to 20 carbon atoms, and a thermally dissociable blocking agent. And a block polyisocyanate composition having a molar ratio of isocyanurate groups to allophanate groups in the polyisocyanate of 10/90 to 80/20 and an organic solvent content of 5 % by mass or less, and containing an organic solvent. method for producing a rate includes the step of mixing the active hydrogen compound is not more than 5 wt%, the curable composition organic solvent content is not more than 5 wt%.   The method for producing a curable composition according to claim 1, wherein the thermally dissociable blocking agent is at least one selected from oxime, acid amide, amine, active methylene and pyrazole compounds.   The method for producing a curable composition according to claim 1 or 2, wherein at least one diisocyanate compound selected from the aliphatic diisocyanate and the alicyclic diisocyanate is hexamethylene diisocyanate. It is obtained from an active hydrogen compound having an organic solvent content of 5 % by mass or less as a main agent, at least one diisocyanate compound selected from aliphatic diisocyanates and alicyclic diisocyanates, and monoalcohols having 1 to 20 carbon atoms. A block polyisocyanate composition obtained from a polyisocyanate and a thermally dissociable blocking agent, wherein the molar ratio of isocyanurate groups to allophanate groups in the polyisocyanate is 10/90 to 80/20, and contains an organic solvent rate contains 5 wt% or less is a blocked polyisocyanate composition, the curable composition is an organic solvent content of 5 wt% or less. Polyols obtained from a polyol compound having an organic solvent content of 5 % by mass or less as a main agent, at least one diisocyanate compound selected from aliphatic diisocyanates and alicyclic diisocyanates, and monoalcohols having 1 to 20 carbon atoms A block polyisocyanate composition obtained from an isocyanate and a heat dissociable blocking agent, wherein the molar ratio of the isocyanurate group to the allophanate group in the polyisocyanate is 10/90 to 80/20, and the organic solvent content is There containing blocked polyisocyanate composition is not more than 5 wt%, polyurethane curable composition is an organic solvent content of 5 wt% or less.   The hardening composition obtained by heat-hardening the curable composition of Claim 4.   A polyurethane curable composition obtained by heat-curing the polyurethane curable composition according to claim 5.