Water-dispersible polyisocyanate, aqueous polyurethane resin composition, and article

Abstract

To provide a water-dispersed polyisocyanate having excellent curability, water dispersibility and pot life, an aqueous polyurethane resin composition and an article.SOLUTION: The water-dispersed polyisocyanate contains isocyanate groups and sulfone groups. The water-dispersed polyisocyanate includes a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component includes a first polyisocyanate containing pentamethylene diisocyanate and a second polyisocyanate containing a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component includes a sulfonic group-containing active hydrogen compound. A content ratio of the first polyisocyanate is 40 mass% or more and 90 mass% or less based on a total amount of the first polyisocyanate and the second polyisocyanate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a water-dispersible polyisocyanate, an aqueous polyurethane resin composition, and an article.

Background Art

[0002] Polyurethane resins are widely used in various industrial fields. A polyurethane resin contains a reaction product of a polyisocyanate component and a polyol component.

[0003] The polyisocyanate component is prepared, for example, as an organic solvent solution. In recent years, in order to improve environmental performance and workability, it has been required to prepare the polyisocyanate component as an aqueous dispersion. That is, a polyisocyanate component dispersible in water has been required.

[0004] As the polyisocyanate component dispersible in water, the following have been proposed. That is, a polyisocyanate mixture obtained by the reaction of isocyanurate of pentamethylene 1,5-diisocyanate and 3-(cyclohexylamino)propanesulfonic acid (see, for example, Patent Document 1 (Example 5)).

[0005] The above polyisocyanate mixture is made water-dispersible by the sulfone group of 3-(cyclohexylamino)propanesulfonic acid. Further, a polyurethane resin is obtained by the reaction of the above polyisocyanate mixture and a polyol component. Such a polyisocyanate mixture and a polyurethane resin are excellent in curability.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when pentamethylene 1,5 - diisocyanate and / or its derivatives are dispersed in water by sulfone groups, the pot life is not sufficient.

[0008] The present invention relates to a water - dispersible polyisocyanate, an aqueous polyurethane resin composition, and an article having excellent curability, water - dispersibility, and pot life.

Means for Solving the Problems

[0009] The present invention [1] is a water - dispersible polyisocyanate containing an isocyanate group and a sulfone group, including a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component includes a first polyisocyanate containing pentamethylene diisocyanate and a second polyisocyanate containing a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component includes a sulfone - group - containing active hydrogen compound, and the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less based on the total amount of the first polyisocyanate and the second polyisocyanate.

[0010] The present invention [2] includes the water - dispersible polyisocyanate according to [1] above, wherein the first polyisocyanate includes an isocyanurate derivative of pentamethylene diisocyanate, and the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is 60% by mass or more based on the total amount of the first polyisocyanate.

[0011] The present invention [3] includes the water - dispersible polyisocyanate according to [2] above, wherein the isocyanurate derivative of pentamethylene diisocyanate includes a reaction product of a pentamethylene diisocyanate monomer and an alcohol.

[0012] The present invention [4] contains the aqueous dispersion-type polyisocyanate described in [3] above, wherein the alcohol contains a monoalcohol.

[0013] The present invention [5] contains the aqueous dispersion-type polyisocyanate according to any one of [1] to [4] above, wherein the second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms, and the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is 25% by mass or more and 75% by mass or less based on the total amount of the second polyisocyanate.

[0014] The present invention [6] contains the aqueous dispersion-type polyisocyanate according to any one of [1] to [5] above, wherein the content ratio of the sulfone group is 0.2% by mass or more and 5% by mass or less based on the total amount of the aqueous dispersion-type polyisocyanate.

[0015] The present invention [7] contains the aqueous dispersion-type polyisocyanate according to any one of [1] to [6] above, wherein the isocyanate groups of the aqueous dispersion-type polyisocyanate are blocked by a blocking agent.

[0016] The present invention [8] contains an aqueous polyurethane resin composition containing the aqueous dispersion-type polyisocyanate according to any one of [1] to [7] above and an active hydrogen group-containing compound.

[0017] The present invention [9] contains an article comprising an object to be coated and a polyurethane layer disposed on the surface of the object to be coated, wherein the polyurethane layer contains a cured product of the aqueous polyurethane resin composition described in [8] above.

Effects of the Invention

[0018] The water-dispersible polyisocyanate of the present invention contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component includes a first polyisocyanate containing pentamethylene diisocyanate and a second polyisocyanate containing a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component includes a sulfone group-containing active hydrogen compound.

[0019] And the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less with respect to the total amount of the first polyisocyanate and the second polyisocyanate. Therefore, the water-dispersible polyisocyanate of the present invention has excellent curability, water dispersibility, and pot life.

[0020] Further, the aqueous polyurethane resin composition of the present invention contains the above water-dispersible polyisocyanate. Therefore, the aqueous polyurethane resin composition of the present invention has excellent curability, water dispersibility, and pot life.

[0021] Since the article of the present invention includes a cured coating film of the above aqueous polyurethane resin composition, it has excellent productivity.

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] The water-dispersible polyisocyanate of the present invention contains an isocyanate group and a sulfone group. Further, the water-dispersible polyisocyanate is a water-dispersible polyisocyanate. And the water-dispersible polyisocyanate contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component.

[0023] The polyisocyanate component includes a first polyisocyanate and a second polyisocyanate.

[0024] The first polyisocyanate includes pentamethylene diisocyanate. The first polyisocyanate preferably consists of pentamethylene diisocyanate. Pentamethylene diisocyanate refers to a pentamethylene diisocyanate monomer and / or its derivative. In the following, a derivative of the pentamethylene diisocyanate monomer is referred to as a pentamethylene diisocyanate derivative.

[0025] Examples of the pentamethylene diisocyanate monomer include 1,5-pentamethylene diisocyanate (1,5-pentane diisocyanate) and its structural isomers. Examples of the structural isomers include 1,4-pentamethylene diisocyanate (1,4-pentane diisocyanate), 1,3-pentamethylene diisocyanate (1,3-pentane diisocyanate), and 1,2-pentamethylene diisocyanate (1,2-pentane diisocyanate). These pentamethylene diisocyanate monomers can be used alone or in combination of two or more. Preferably, 1,5-pentamethylene diisocyanate is mentioned as the pentamethylene diisocyanate monomer. Note that the pentamethylene diisocyanate monomer can be produced, for example, in accordance with the description in International Publication No. 2012 / 121291.

[0026] Examples of the pentamethylene diisocyanate derivative include derivatives obtained by modifying the pentamethylene diisocyanate monomer by a known method. More specifically, examples of the pentamethylene diisocyanate derivative include multimers, allophanate derivatives, polyol derivatives, biuret derivatives, urea derivatives, oxadiazinetrione derivatives, and carbodiimide derivatives. Examples of the multimer include isocyanurate derivatives and iminooxadiazinedione derivatives. These pentamethylene diisocyanate derivatives can be used alone or in combination of two or more.

[0027] Pentamethylene diisocyanate can be used alone or in combination of two or more. As the pentamethylene diisocyanate, preferably, a pentamethylene diisocyanate derivative is mentioned, and more preferably, an isocyanurate derivative of pentamethylene diisocyanate is mentioned. In other words, the first polyisocyanate preferably contains an isocyanurate derivative of pentamethylene diisocyanate.

[0028] Examples of the isocyanurate derivative of pentamethylene diisocyanate include reaction products of a pentamethylene diisocyanate monomer and an alcohol.

[0029] More specifically, the isocyanurate derivative of pentamethylene diisocyanate is produced, for example, by the following method. That is, in this method, first, a pentamethylene diisocyanate monomer and an alcohol are reacted.

[0030] Examples of the alcohol include monohydric alcohols, dihydric alcohols, and trihydric alcohols.

[0031] Examples of the monohydric alcohol include linear monohydric alcohols and branched monohydric alcohols.

[0032] Examples of the linear monohydric alcohol include methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol, n-tetradecanol, n-pentadecanol, n-hexadecanol, n-heptadecanol, n-octadecanol, n-nonadecanol, and eicosanol. These can be used alone or in combination of two or more.

[0033] Examples of branched monohydric alcohols include isopropanol, isobutanol (isobutyl alcohol), sec-butanol, tert-butanol, isopentanol, isohexanol, isoheptanol, isooctanol, 2-ethylhexan-1-ol, isononanol, isodecanol, 5-ethyl-2-nonanol, trimethylnonyl alcohol, 2-hexyldecanol, 3,9-diethyl-6-tridecanol, 2-isoheptylisoundecanol, and 2-octyldodecanol. These can be used alone or in combination of two or more. These monoalcohols can be used alone or in combination of two or more.

[0034] Examples of diols include linear dihydric alcohols and branched dihydric alcohols.

[0035] Examples of linear dihydric alcohols include linear alkanediols. Examples of linear alkanediols include ethylene glycol, 1,3-propanediol, 1,4-butanediol (1,4-butylene glycol), 1,5-pentanediol, 1,6-hexanediol, 1,4-dihydroxy-2-butene, diethylene glycol, triethylene glycol, and dipropylene glycol. These can be used alone or in combination of two or more.

[0036] Examples of branched dihydric alcohols include branched alkanediols. Examples of branched alkanediols include 1,2-propanediol, 1,3-butanediol, 1,2-butylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dimethylolheptane, and 2,6-dimethyl-1-octene-3,8-diol. These can be used alone or in combination of two or more.

[0037] These diols can be used alone or in combination of two or more.

[0038] Examples of the triol include glycerin, trimethylolpropane, and triisopropanolamine. These can be used alone or in combination of two or more kinds.

[0039] These triols can be used alone or in combination of two or more kinds.

[0040] These alcohols can be used alone or in combination of two or more kinds.

[0041] The number of carbon atoms of the alcohol is, for example, 1 or more, preferably 2 or more. Also, the number of carbon atoms of the alcohol is, for example, 50 or less, preferably 40 or less, more preferably 30 or less, still more preferably 20 or less, still more preferably 10 or less, particularly preferably 4 or less.

[0042] If the number of carbon atoms of the alcohol is within the above range, the water dispersibility of the isocyanurate derivative of pentamethylene diisocyanate can be improved.

[0043] As the alcohol, preferably a monool is mentioned, more preferably a branched monohydric alcohol is mentioned, and still more preferably isobutanol is mentioned. By using these, the water dispersibility of the water-dispersible polyisocyanate can be improved.

[0044] The blending ratio of the pentamethylene diisocyanate monomer and the alcohol is appropriately set within a range that does not inhibit the excellent effects of the present invention.

[0045] More specifically, the equivalent ratio (NCO / OH) of the isocyanate group of the pentamethylene diisocyanate monomer to the hydroxyl group of the alcohol is, for example, more than 1, preferably 5 or more, more preferably 10 or more. Also, the equivalent ratio (NCO / OH) of the isocyanate group of the pentamethylene diisocyanate monomer to the hydroxyl group of the alcohol is, for example, 1000 or less, preferably 600 or less, more preferably 500 or less, still more preferably 100 or less.

[0046] Further, the alcohol is, for example, 3 parts by mass or more, preferably 3.2 parts by mass or more, more preferably 3.5 parts by mass or more with respect to 100 parts by mass of the pentamethylene diisocyanate monomer. Also, the alcohol is, for example, 50 parts by mass or less, preferably 20 parts by mass or less, more preferably 10 parts by mass or less with respect to 100 parts by mass of the pentamethylene diisocyanate monomer.

[0047] The reaction conditions between the pentamethylene diisocyanate monomer and the alcohol are appropriately set within a range that does not inhibit the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. Also, the reaction temperature is, for example, 20°C or higher, preferably 40°C or higher. Also, the reaction temperature is, for example, 100°C or lower, preferably 90°C or lower. Also, the reaction time is, for example, 0.05 hours or more, preferably 0.2 hours or more. Also, the reaction time is, for example, 10 hours or less, preferably 6 hours or less.

[0048] Also, in this method, a urethanization catalyst can be blended with the pentamethylene diisocyanate monomer and the alcohol as needed. Examples of the urethanization catalyst include known amines and known organometallic compounds. The blending ratio of the urethanization catalyst is not particularly limited and is appropriately set according to the purpose and application.

[0049] Thereby, the pentamethylene diisocyanate monomer and the alcohol undergo a urethanization reaction. As a result, a urethanization reaction product is obtained.

[0050] Next, in this method, the urethanization reaction product is subjected to an allophanatization reaction and an isocyanuration reaction.

[0051] More specifically, in this method, an isocyanuration catalyst is blended with the urethanization reaction product and heated.

[0052] The isocyanurate-forming catalyst is not particularly limited as long as it can promote the allophanatization and isocyanuration of isocyanate groups. Examples of the isocyanurate-forming catalyst include tertiary amines, Mannich bases, Friedel-Crafts catalysts, metal salts of alkyl carboxylic acids, organometallic compounds, halogen-substituted organophosphorus compounds, hydroxides of tetraalkylammonium, organic weak acid salts of tetraalkylammonium, hydroxides of trialkylhydroxyalkylammonium, and organic weak acid salts of trialkylhydroxyalkylammonium. These can be used alone or in combination of two or more.

[0053] Preferred examples of the isocyanurate-forming catalyst include organic weak acid salts of trialkylhydroxyalkylammonium.

[0054] Examples of the trialkylhydroxyalkylammonium include N-(2-hydroxypropyl)-N,N,N-trimethylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium. These can be used alone or in combination of two or more.

[0055] Examples of the organic weak acid salt include acetate, propionate, 2-ethylhexanoate, octylate, caprinate, myristate, and benzoate. These can be used alone or in combination of two or more.

[0056] The blending ratio of the isocyanurate-forming catalyst is, for example, 0.0005 parts by mass or more, preferably 0.001 parts by mass or more, based on 100 parts by mass of the pentamethylene diisocyanate monomer. Also, the blending ratio of the isocyanurate-forming catalyst is, for example, 0.3 parts by mass or less, preferably 0.05 parts by mass or less, more preferably 0.03 parts by mass or less, based on 100 parts by mass of the pentamethylene diisocyanate monomer.

[0057] The reaction conditions of the allophanate reaction and the isocyanurate reaction are appropriately set within a range that does not inhibit the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. Also, the reaction temperature is, for example, 0°C or higher, preferably 20°C or higher. Further, the reaction temperature is, for example, 160°C or lower, preferably 120°C or lower. Also, the reaction time is, for example, 30 minutes or longer, preferably 60 minutes or longer. Also, the reaction time is, for example, 20 hours or shorter, preferably 10 hours or shorter.

[0058] And when the reaction rate (isocyanate group conversion rate) of the reaction solution reaches a predetermined value, a reaction terminator is added to the reaction solution. The conversion rate of the isocyanate group when stopping the reaction is, for example, 1% by mass or more, preferably 5% by mass or more. Also, the conversion rate of the isocyanate group when stopping the reaction is, for example, 20% by mass or less, preferably 15% by mass or less. Note that the conversion rate of the isocyanate group can be calculated by a known method.

[0059] Examples of the reaction terminator include phosphoric acid, monochloroacetic acid, benzoyl chloride, dodecylbenzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid, methyl o-toluenesulfonate, methyl p-toluenesulfonate, o-toluenesulfonamide, and p-toluenesulfonamide. These can be used alone or in combination of two or more. The blending ratio of the reaction terminator is appropriately set according to the purpose and application.

[0060] Also, instead of the reaction terminator, a catalyst adsorbent can be added. Examples of the catalyst adsorbent include chelate resins and ion exchange resins. These can be used alone or in combination of two or more. The blending ratio of the catalyst adsorbent is appropriately set according to the purpose and application.

[0061] Thereby, the allophanate reaction and the isocyanurate reaction are stopped.

[0062] In addition, in each of the above reactions, a cocatalyst can be added. Examples of the cocatalyst include known organic phosphite esters. Preferred examples of the organic phosphite esters include monophosphites, and more preferred is tris(tridecyl) phosphite.

[0063] The blending ratio of the cocatalyst is, for example, 0.01 parts by mass or more, preferably 0.02 parts by mass or more, and more preferably 0.03 parts by mass or more with respect to 100 parts by mass of the pentamethylene diisocyanate monomer. Also, the blending ratio of the cocatalyst is, for example, 0.2 parts by mass or less, preferably 0.15 parts by mass or less, and more preferably 0.1 parts by mass or less with respect to 100 parts by mass of the pentamethylene diisocyanate monomer.

[0064] In addition, in each of the above reactions, a reaction stabilizer can be added. Examples of the reaction stabilizer include known hindered phenol antioxidants. Preferred is 2,6-di(tert-butyl)-4-methylphenol (BHT).

[0065] The blending ratio of the reaction stabilizer is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the pentamethylene diisocyanate monomer. Also, the blending ratio of the reaction stabilizer is, for example, 1.0 parts by mass or less, preferably 0.10 parts by mass or less with respect to 100 parts by mass of the pentamethylene diisocyanate monomer.

[0066] In addition, in each of the above reactions, a known reaction solvent can be added. Note that the blending ratio of the reaction solvent is appropriately set according to the purpose and application. Also, in each of the above reactions, the reaction solution can be purified. Examples of the purification method include distillation and extraction. By purification, unreacted pentamethylene diisocyanate monomer is removed from the reaction solution. Also, the urethanization catalyst, isocyanuration catalyst, catalyst deactivator, cocatalyst, reaction stabilizer and / or reaction solvent are removed together with the pentamethylene diisocyanate monomer.

[0067] In the above reaction, the pentamethylene diisocyanate monomer is isocyanurated. As a result, an isocyanurate derivative of pentamethylene diisocyanate is obtained as the reaction product. And the reaction product is used as the first polyisocyanate.

[0068] In the first polyisocyanate, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is appropriately set according to the purpose and application. More specifically, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 50% by mass or more, still more preferably 60% by mass or more, still more preferably 70% by mass or more, particularly preferably 80% by mass or more, based on the total amount of the first polyisocyanate.

[0069] When the content ratio of the isocyanurate derivative exceeds the above lower limit, a water-dispersible polyisocyanate having excellent curability and water dispersibility can be obtained.

[0070] Also, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is, for example, 100% by mass or less based on the total amount of the first polyisocyanate. That is, the first polyisocyanate can consist of the isocyanurate derivative of pentamethylene diisocyanate.

[0071] Also, in the above reaction, depending on the reaction conditions, the pentamethylene diisocyanate monomer may be isocyanurated and allophanatized. As a result, the first polyisocyanate may contain an isocyanurate derivative of pentamethylene diisocyanate and an allophanate derivative of pentamethylene diisocyanate.

[0072] When the first polyisocyanate contains an isocyanurate derivative of pentamethylene diisocyanate and an allophanate derivative of pentamethylene diisocyanate, their content ratios are appropriately set according to the purpose and use.

[0073] In such a case, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 50% by mass or more, still more preferably 60% by mass or more, still more preferably 70% by mass or more, particularly preferably 75% by mass or more, based on the total amount of the first polyisocyanate. Also, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 80% by mass or less, based on the total amount of the first polyisocyanate.

[0074] In addition, the content ratio of the allophanate derivative of pentamethylene diisocyanate is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, based on the total amount of the first polyisocyanate. Also, the content ratio of the allophanate derivative of pentamethylene diisocyanate is, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 50% by mass or less, still more preferably 40% by mass or less, still more preferably 30% by mass or less, particularly preferably 25% by mass or less, based on the total amount of the first polyisocyanate.

[0075] The content ratio of the isocyanurate derivative and the content ratio of the allophanate derivative are measured by gel permeation chromatography in accordance with the examples described below.

[0076] Also, in the above method, the isocyanurate derivative of pentamethylene diisocyanate and the allophanate derivative of pentamethylene diisocyanate are produced simultaneously. However, for example, the isocyanurate derivative of pentamethylene diisocyanate and the allophanate derivative of pentamethylene diisocyanate may be produced individually and mixed in the above ratio. Further, an isocyanurate derivative of pentamethylene diisocyanate and / or an allophanate derivative of pentamethylene diisocyanate may be added to the above reaction product and adjusted to the above ratio.

[0077] Also, the first polyisocyanate may be dissolved in a known organic solvent. In such a case, the solid content concentration of the solution of the first polyisocyanate is, for example, 10% by mass or more, preferably 20% by mass or more. Also, the solid content concentration of the solution of the first polyisocyanate is, for example, 90% by mass or less, preferably 80% by mass or less.

[0078] The second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms. The second polyisocyanate preferably consists of a polyisocyanate having 6 or more carbon atoms. The polyisocyanate having 6 or more carbon atoms refers to a polyisocyanate monomer having 6 or more carbon atoms and / or its derivative. In the following, a derivative of a polyisocyanate monomer having 6 or more carbon atoms is referred to as a polyisocyanate derivative having 6 or more carbon atoms.

[0079] Examples of the polyisocyanate monomer having 6 or more carbon atoms include an aliphatic polyisocyanate monomer having 6 or more carbon atoms, an alicyclic polyisocyanate monomer having 6 or more carbon atoms, an aromatic polyisocyanate monomer having 6 or more carbon atoms, and an araliphatic polyisocyanate monomer having 6 or more carbon atoms.

[0080] Examples of the aliphatic polyisocyanate monomer having 6 or more carbon atoms include a hexamethylene diisocyanate monomer. These can be used alone or in combination of two or more.

[0081] Examples of the alicyclic polyisocyanate monomer having 6 or more carbon atoms include isophorone diisocyanate monomer, norbornene diisocyanate monomer, bis(isocyanatomethyl)cyclohexane monomer, and methylene bis(cyclohexyl isocyanate) monomer. These can be used alone or in combination of two or more kinds.

[0082] Examples of the aromatic polyisocyanate monomer having 6 or more carbon atoms include tolylene diisocyanate, naphthalene diisocyanate, and diphenylmethane diisocyanate. These can be used alone or in combination of two or more kinds.

[0083] These polyisocyanate monomers having 6 or more carbon atoms can be used alone or in combination of two or more kinds.

[0084] Examples of the polyisocyanate derivative having 6 or more carbon atoms include derivatives of the same kind as described above.

[0085] As the polyisocyanate having 6 or more carbon atoms, preferably, polyisocyanate derivatives having 6 or more carbon atoms are included, and more preferably, isocyanurate derivatives of polyisocyanates having 6 or more carbon atoms are included. In other words, the second polyisocyanate preferably includes an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms.

[0086] The isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms can be produced by a known method. Also, the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms can be produced, for example, in the same manner as the isocyanurate derivative of pentamethylene diisocyanate.

[0087] The content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, and still more preferably 50% by mass or more based on the total amount of the second polyisocyanate.

[0088] If the content ratio of the isocyanurate derivative exceeds the above lower limit, a water-dispersible polyisocyanate having excellent curability and water dispersibility can be obtained.

[0089] Further, the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 100% by mass or less with respect to the total amount of the second polyisocyanate. That is, the second polyisocyanate can be composed of an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms.

[0090] Further, the second polyisocyanate may contain an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and an allophanate derivative of a polyisocyanate having 6 or more carbon atoms.

[0091] Preferably, the second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and an allophanate derivative of a polyisocyanate having 6 or more carbon atoms.

[0092] When the second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and an allophanate derivative of a polyisocyanate having 6 or more carbon atoms, their content ratios are appropriately set according to the purpose and application.

[0093] In such a case, the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, particularly preferably 40% by mass or more with respect to the total amount of the second polyisocyanate. Further, the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 75% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less with respect to the total amount of the second polyisocyanate.

[0094] In addition, the content ratio of the allophanate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 25% by mass or more, still more preferably 30% by mass or more, particularly preferably 40% by mass or more, based on the total amount of the second polyisocyanate. Further, the content ratio of the allophanate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less, based on the total amount of the second polyisocyanate.

[0095] In addition, the second polyisocyanate may be dissolved in a known organic solvent. In such a case, the solid content concentration of the solution of the second polyisocyanate is, for example, 10% by mass or more, preferably 20% by mass or more. Further, the solid content concentration of the solution of the second polyisocyanate is, for example, 90% by mass or less, preferably 80% by mass or less.

[0096] The polyisocyanate component can further contain other polyisocyanates as long as it contains the first polyisocyanate and the second polyisocyanate.

[0097] Preferably, the polyisocyanate component contains only the first polyisocyanate and the second polyisocyanate. That is, preferably, the polyisocyanate component consists of the first polyisocyanate and the second polyisocyanate.

[0098] The content ratio of the first polyisocyanate is 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, particularly preferably 60% by mass or more, based on the total amount of the first polyisocyanate and the second polyisocyanate. Further, the content ratio of the first polyisocyanate is 90% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, based on the total amount of the first polyisocyanate and the second polyisocyanate.

[0099] The content ratio of the second polyisocyanate is, for example, 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more, based on the total amount of the first polyisocyanate and the second polyisocyanate. Further, the content ratio of the second polyisocyanate is, for example, 60% by mass or less, preferably 55% by mass or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, particularly preferably 40% by mass or less, based on the total amount of the first polyisocyanate and the second polyisocyanate.

[0100] When the content ratio of the first polyisocyanate and the content ratio of the second polyisocyanate are within the above ranges, a water-dispersible polyisocyanate having excellent curability, water dispersibility, and pot life can be obtained.

[0101] Further, the polyisocyanate component may be dissolved in a known organic solvent. In such a case, the solid content concentration of the solution of the polyisocyanate component is, for example, 10% by mass or more, preferably 20% by mass or more. Further, the solid content concentration of the solution of the polyisocyanate component is, for example, 90% by mass or less, preferably 80% by mass or less.

[0102] And a water-dispersible polyisocyanate is obtained by reacting the above polyisocyanate component with a hydrophilic active hydrogen component.

[0103] More specifically, in the preparation of the water-dispersible polyisocyanate, the polyisocyanate component and the hydrophilic active hydrogen component are reacted at a ratio where free isocyanate groups remain.

[0104] The method for producing the water-dispersible polyisocyanate is not particularly limited.

[0105] For example, first, a first polyisocyanate and a second polyisocyanate are mixed at the above ratio to prepare a mixed polyisocyanate. Next, the mixed polyisocyanate and the hydrophilic active hydrogen component are reacted. Thereby, a water-dispersible polyisocyanate can be obtained.

[0106] Also, for example, first, the first polyisocyanate and the hydrophilic active hydrogen component are reacted to prepare a first water-dispersible polyisocyanate. Also, the second polyisocyanate and the hydrophilic active hydrogen component are reacted to prepare a second water-dispersible polyisocyanate. Then, the first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate are mixed. In the mixing, the ratio of the first polyisocyanate and the second polyisocyanate is adjusted so as to be within the above range. Thereby, a water-dispersible polyisocyanate can be obtained.

[0107] Preferably, first, the first polyisocyanate and the hydrophilic active hydrogen component are reacted to prepare a first water-dispersible polyisocyanate. Also, the second polyisocyanate and the hydrophilic active hydrogen component are reacted to prepare a second water-dispersible polyisocyanate. Then, the first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate are mixed. Thereby, a water-dispersible polyisocyanate is obtained.

[0108] The hydrophilic active hydrogen component contains a sulfone group-containing active hydrogen compound.

[0109] The sulfone group-containing active hydrogen compound is a compound containing one or more sulfone groups and one or more active hydrogen groups. Examples of the active hydrogen group include a hydroxyl group and an amino group.

[0110] Examples of the sulfone group-containing active hydrogen compound include compounds having one active hydrogen group and one sulfone group. Examples of such sulfone group-containing active hydrogen compounds include hydroxyalkanesulfonic acid and aminosulfonic acid.

[0111] Examples of the hydroxyalkanesulfonic acid include hydroxymethanesulfonic acid, hydroxyethanesulfonic acid, and 3-hydroxypropanesulfonic acid. These can be used alone or in combination of two or more.

[0112] Examples of the aminosulfonic acid include 2-(cyclohexylamino)-ethanesulfonic acid (CHES) and 3-(cyclohexylamino)-propanesulfonic acid (CAPS). These can be used alone or in combination of two or more.

[0113] These sulfone group-containing active hydrogen compounds can be used alone or in combination of two or more.

[0114] Preferred examples of the sulfone group-containing active hydrogen compound include aminosulfonic acid, and more preferred is 3-(cyclohexylamino)-propanesulfonic acid.

[0115] In addition, the hydrophilic active hydrogen component can contain other water-dispersible active hydrogen compounds as optional components.

[0116] The other water-dispersible active hydrogen compounds are water-dispersible active hydrogen compounds excluding the sulfone group-containing active hydrogen compounds.

[0117] More specifically, examples of the other water-dispersible active hydrogen compounds include nonionic group-containing active hydrogen compounds, carboxyl group-containing active hydrogen compounds, and phosphate group-containing active hydrogen compounds.

[0118] Examples of the nonionic group-containing active hydrogen compound include polyoxyethylene compounds.

[0119] Examples of the polyoxyethylene compound include compounds having an active hydrogen group and at least three consecutive ethylene oxide groups. Examples of such polyoxyethylene compounds include mono-terminally blocked polyoxyethylene glycol and diol containing a polyoxyethylene side chain.

[0120] Examples of the mono-terminally blocked polyoxyethylene glycol include alkoxypolyethylene glycol having one terminal blocked with an alkyl group having 1 to 20 carbon atoms. More specifically, methoxypolyoxyethylene glycol and ethoxypolyoxyethylene glycol are included. The mono-terminally blocked polyoxyethylene glycol can be produced by a known method.

[0121] Examples of the diol containing a polyoxyethylene side chain include reaction products of a polyoxyethylene group-containing monoisocyanate and a dialkanolamine. The diol containing a polyoxyethylene side chain can be produced by a known method.

[0122] The polyoxyethylene compound can be used alone or in combination of two or more.

[0123] The number average molecular weight of the polyoxyethylene compound is, for example, 200 or more, preferably 300 or more, for example, 2000 or less, preferably 1000 or less.

[0124] The carboxyl group-containing active hydrogen compound is a compound having an active hydrogen group and a carboxyl group. Examples of the carboxyl group-containing active hydrogen compound include a carboxyl group-containing active hydrogen compound having one active hydrogen group and one carboxyl group. Further, examples of the carboxyl group-containing active hydrogen compound include a carboxyl group-containing active hydrogen compound having two active hydrogen groups and one carboxyl group.

[0125] Examples of the carboxyl group-containing active hydrogen compound having one active hydrogen group and one carboxyl group include glycolic acid, lactic acid, hydroxypivalic acid, malic acid, and citric acid.

[0126] Examples of the carboxyl group-containing active hydrogen compound having two active hydrogen groups and one carboxyl group include 2,2-dimethylolacetic acid, 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, dimethylolheptanoic acid, dimethylolnonanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid.

[0127] The carboxyl group-containing active hydrogen compound can be used alone or in combination of two or more.

[0128] The phosphoric acid group-containing active hydrogen compound is a compound having an active hydrogen group and a phosphoric acid group.

[0129] Examples of the phosphoric acid group-containing active hydrogen compound include a phosphoric acid group-containing active hydrogen compound having one active hydrogen group and one phosphoric acid group.

[0130] Examples of such phosphoric acid group-containing active hydrogen compounds include hydroxyalkylphosphonic acid and aminoalkylphosphonic acid.

[0131] The phosphoric acid group-containing active hydrogen compound can be used alone or in combination of two or more.

[0132] Other water-dispersible active hydrogen compounds can be used alone or in combination of two or more.

[0133] The content ratio of other water-dispersible active hydrogen compounds is, for example, 90% by mass or less, preferably 70% by mass or less, more preferably 50% by mass or less, still more preferably 30% by mass or less, still more preferably 10% by mass or less, and particularly preferably 0% by mass, based on the total amount of the hydrophilic active hydrogen component.

[0134] That is, the hydrophilic active hydrogen component preferably consists of a sulfone group-containing active hydrogen compound and does not contain other water-dispersible active hydrogen compounds.

[0135] When the hydrophilic active hydrogen component consists of a sulfone group-containing active hydrogen compound, a polyurethane resin with particularly excellent hardness and mechanical properties can be obtained, and a water-dispersible polyisocyanate with excellent curability and water dispersibility can also be obtained.

[0136] The reaction ratio between the first polyisocyanate and the hydrophilic active hydrogen component is adjusted so that free isocyanate groups remain in the reaction product.

[0137] More specifically, the equivalent ratio of the active hydrogen groups of the hydrophilic active hydrogen component to the isocyanate groups of the first polyisocyanate (active hydrogen groups / NCO) is, for example, 0.30 or less, preferably 0.20 or less. Also, the equivalent ratio of the active hydrogen groups of the hydrophilic active hydrogen component to the isocyanate groups of the first polyisocyanate (active hydrogen groups / NCO) is, for example, 0.01 or more, preferably 0.10 or more.

[0138] The compounding ratio of the hydrophilic active hydrogen component is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, more preferably 25 parts by mass or more, based on 100 parts by mass of the first polyisocyanate. Also, the compounding ratio of the hydrophilic active hydrogen component is, for example, 70 parts by mass or less, preferably 60 parts by mass or less, more preferably 55 parts by mass or less, based on 100 parts by mass of the first polyisocyanate.

[0139] The reaction conditions of the first polyisocyanate and the hydrophilic active hydrogen component are appropriately set within a range that does not inhibit the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. Also, the reaction temperature is, for example, 50 °C or higher, preferably 70 °C or higher. Also, the reaction temperature is, for example, 150 °C or lower, preferably 110 °C or lower. Also, the reaction time is, for example, 0.5 hours or longer, preferably 1 hour or longer. Also, the reaction time is, for example, 120 hours or shorter, preferably 72 hours or shorter.

[0140] In addition, the end of the reaction is confirmed, for example, by the isocyanate amount in the reaction solution no longer changing. The isocyanate amount is measured by a titration method or an infrared absorption method.

[0141] Also, in this method, preferably, a neutralizing agent is added to the reaction solution to form a salt of the sulfone group. That is, the sulfone group does not have to be a salt, and it may be a salt. Preferably, examples of the sulfone group include salts of the sulfone group.

[0142] Examples of the neutralizing agent include conventional bases. Specific examples of the base include organic bases and inorganic bases.

[0143] Examples of the organic base include tertiary amines and secondary amines. Examples of the tertiary amine include trialkylamines and alkanolamines. Examples of the trialkylamine include trimethylamine, triethylamine, and N,N-dimethylcyclohexylamine. Examples of the alkanolamine include dimethylethanolamine, methyldiethanolamine, triethanolamine, and triisopropanolamine. Examples of the secondary amine include heterocyclic amines. Examples of the heterocyclic amine include morpholine. These organic bases can be used alone or in combination of two or more.

[0144] Examples of the inorganic base include ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal carbonates. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the alkaline earth metal hydroxide include magnesium hydroxide and calcium hydroxide. Examples of the alkali metal carbonate include sodium carbonate and potassium carbonate. These inorganic bases can be used alone or in combination of two or more.

[0145] These neutralizing agents can be used alone or in combination of two or more.

[0146] Preferred examples of the neutralizing agent include organic bases, more preferred examples include tertiary amines, still more preferred examples include trialkylamines, and particularly preferred examples include N,N-dimethylcyclohexylamine.

[0147] The addition amount of the neutralizing agent is, for example, 0.4 equivalent or more, preferably 0.6 equivalent or more, based on 1 equivalent of the sulfone group. Also, the addition amount of the neutralizing agent is, for example, 1.2 equivalents or less, preferably 1.0 equivalent or less, based on 1 equivalent of the sulfone group.

[0148] Thereby, a first water-dispersible polyisocyanate containing an isocyanate group and a sulfone group is obtained.

[0149] Also, in this method, a second water-dispersible polyisocyanate is prepared in the same manner as the first water-dispersible polyisocyanate. That is, first, a second polyisocyanate and a hydrophilic active hydrogen component are reacted in the same manner as above, and then the reaction product is neutralized in the same manner as above.

[0150] Thereby, a second water-dispersible polyisocyanate containing an isocyanate group and a sulfone group is obtained.

[0151] Thereafter, in this method, a first water-dispersible polyisocyanate and a second water-dispersible polyisocyanate are mixed. The mixing ratio is adjusted so that the ratio of the first polyisocyanate in the first water-dispersible polyisocyanate and the ratio of the second polyisocyanate in the second water-dispersible polyisocyanate are within the above ranges.

[0152] Thereby, a water-dispersible polyisocyanate containing an isocyanate group and a sulfone group is obtained.

[0153] In addition, in the water-dispersible polyisocyanate, the isocyanate group may be a free isocyanate group. Also, the isocyanate group may be blocked by a blocking agent. That is, examples of the isocyanate group include a free isocyanate group and a blocked isocyanate group.

[0154] The blocking agent is a compound having an active group (hereinafter referred to as a blocking group) that reacts with an isocyanate group. Examples of the blocking agent include active methylene compounds, active methine compounds, imidazole compounds, imidazoline compounds, pyrimidine compounds, guanidine compounds, alcohol compounds, phenol compounds, amine compounds, imine compounds, oxime compounds, carbamic acid compounds, urea compounds, acid amide compounds, lactam compounds, acid imide compounds, triazole compounds, pyrazole compounds, mercaptan compounds, and bisulfites. These can be used alone or in combination of two or more. Preferred examples of the blocking agent include imidazole compounds, imidazoline compounds, oxime compounds, and pyrazole compounds.

[0155] And by reacting a water-dispersible polyisocyanate having a free isocyanate group with the above blocking agent, a water-dispersible polyisocyanate having a blocked isocyanate group is produced.

[0156] The blending ratio of the water-dispersible polyisocyanate having free isocyanate groups and the above blocking agent is adjusted, for example, based on the equivalent ratio of the isocyanate groups in the water-dispersible polyisocyanate and the blocking groups in the blocking agent.

[0157] More specifically, the equivalent ratio of the blocking groups to the free isocyanate groups (blocking groups / isocyanate groups) is, for example, 0.2 or more, preferably 0.5 or more, more preferably 0.8 or more, and still more preferably 1.0 or more. Also, the equivalent ratio of the blocking groups to the free isocyanate groups (blocking groups / isocyanate groups) is, for example, 1.5 or less, preferably 1.2 or less, and more preferably 1.1 or less.

[0158] The reaction conditions of the water-dispersible polyisocyanate having free isocyanate groups and the above blocking agent are appropriately set within a range that does not inhibit the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. Also, the reaction temperature is, for example, 0°C or more, preferably 20°C or more. Also, the reaction temperature is, for example, 100°C or less, preferably 80°C or less, and more preferably 70°C or less. Also, the reaction time is, for example, 0.5 hours or more, preferably 1.0 hours or more. Also, the reaction time is, for example, 24 hours or less, preferably 12 hours or less.

[0159] In addition, the end of the reaction is confirmed, for example, by the isocyanate amount in the reaction solution no longer changing. The isocyanate amount is measured by a titration method or an infrared absorption method.

[0160] Also, each of the above reactions may be carried out without a solvent. Also, each of the above reactions may be carried out in the presence of a solvent. Examples of the solvent include known organic solvents. Also, the blending ratio of the solvent is appropriately set according to the purpose and application.

[0161] Also, when a solvent is used, the solvent can be removed after the reaction is completed. Examples of the method for removing the solvent include distillation and extraction.

[0162] In the following, the isocyanate group refers to a free isocyanate group and an isocyanate group blocked by a blocking agent.

[0163] The average number of isocyanate groups in the water-dispersible polyisocyanate is, for example, 2 or more, preferably 2.2 or more, for example, 4.0 or less, preferably 3.5 or less.

[0164] Also, the content ratio of the isocyanate group is, for example, 5% by mass or more, preferably 7% by mass or more, based on the total amount of the water-dispersible polyisocyanate. Also, the content ratio of the isocyanate group is, for example, 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, based on the total amount of the water-dispersible polyisocyanate.

[0165] Also, the content ratio of the sulfone group is, for example, 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, based on the total amount of the water-dispersible polyisocyanate. Also, the content ratio of the sulfone group is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less, based on the total amount of the water-dispersible polyisocyanate.

[0166] When the content ratio of the sulfone group exceeds the above lower limit, particularly excellent water dispersibility can be obtained. Also, when the content ratio of the sulfone group is below the above upper limit, particularly excellent water resistance can be obtained. The content ratio of the sulfone group can be calculated from the chemical structural formula and the formulation according to the examples described later.

[0167] When the water-dispersible polyisocyanate contains oxyethylene units, the content ratio is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less based on the total amount of the water-dispersible polyisocyanate.

[0168] The content ratio of the oxyethylene units can be calculated from the chemical structural formula and the formulation according to the examples described later.

[0169] The acid value of the water-dispersible polyisocyanate is, for example, 1 mgKOH / g or more, preferably 2 mgKOH / g or more, and more preferably 3 mgKOH / g or more. The acid value of the water-dispersible polyisocyanate is, for example, 56 mgKOH / g or less, preferably 34 mgKOH / g or less, and more preferably 12 mgKOH / g or less.

[0170] The acid value is measured in accordance with JIS K 1557-5 (2007). The acid value can also be determined by calculating the sulfone group content of the water-dispersible polyisocyanate based on the charged amounts of the raw material components.

[0171] If the acid value of the water-dispersible polyisocyanate exceeds the above lower limit, particularly excellent water dispersibility can be obtained. If the acid value of the water-dispersible polyisocyanate is below the above upper limit, particularly excellent water resistance can be obtained.

[0172] And the above water-dispersible polyisocyanate contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component includes a first polyisocyanate containing pentamethylene diisocyanate and a second polyisocyanate containing a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component includes a sulfone group-containing active hydrogen compound. And the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less based on the total amount of the first polyisocyanate and the second polyisocyanate. Therefore, the above water-dispersible polyisocyanate has excellent curability, water dispersibility, and pot life.

[0173] The aqueous polyurethane resin composition contains the above water-dispersible polyisocyanate and an active hydrogen group-containing compound. Note that the aqueous polyurethane resin composition may be a one-component curable polyurethane resin composition in which the water-dispersible polyisocyanate and the active hydrogen group-containing compound are mixed. Also, the polyurethane resin composition may be a two-component curable polyurethane resin composition in which the water-dispersible polyisocyanate and the active hydrogen group-containing compound are separately prepared and blended at the time of use.

[0174] Preferably, the aqueous polyurethane resin composition is a two-component curable polyurethane resin composition.

[0175] The two-component curable polyurethane resin composition contains an active hydrogen group-containing compound as the main agent. Also, the two-component curable polyurethane resin composition contains the above water-dispersible polyisocyanate as the curing agent.

[0176] The main agent contains, for example, an aqueous dispersion of an active hydrogen group-containing compound.

[0177] Examples of the active hydrogen group-containing compound include macro polyols. Macro polyols have two or more hydroxyl groups in the molecule and are relatively high molecular weight organic compounds (polymers). The number average molecular weight of the macro polyol exceeds, for example, 600 and is, for example, 20,000 or less.

[0178] Examples of the macro polyol include polyether polyol, polyester polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, acrylic polyol, and vinyl monomer-modified polyol. These can be used alone or in combination of two or more.

[0179] These active hydrogen group-containing compounds can be used alone or in combination of two or more.

[0180] The aqueous dispersion of the active hydrogen group-containing compound is prepared, for example, by adding water to the active hydrogen group-containing compound. Also, the aqueous dispersion of the active hydrogen group-containing compound can be prepared, for example, by adding the active hydrogen group-containing compound to water.

[0181] In the aqueous dispersion of the active hydrogen group-containing compound, the content ratio of the active hydrogen group-containing compound is appropriately set according to the purpose and application. For example, the active hydrogen group-containing compound (solid content) is, for example, 1% by mass or more, preferably 5% by mass or more, based on the total amount of the aqueous dispersion. Also, the active hydrogen group-containing compound (solid content) is, for example, 30% by mass or less, preferably 20% by mass or less, based on the total amount of the aqueous dispersion.

[0182] The curing agent contains, for example, an aqueous dispersion of a water-dispersible polyisocyanate.

[0183] The aqueous dispersion of the water-dispersible polyisocyanate is prepared, for example, by adding water to the water-dispersible polyisocyanate. Also, the aqueous dispersion of the water-dispersible polyisocyanate can be prepared, for example, by adding the water-dispersible polyisocyanate to water. Also, if necessary, a known external emulsifier can be added to water and / or the water-dispersible polyisocyanate. Also, a known external emulsifier can be added to the mixture of water and the water-dispersible polyisocyanate.

[0184] In the aqueous dispersion of the water-dispersible polyisocyanate, the content ratio of the water-dispersible polyisocyanate is appropriately set according to the purpose and application. For example, with respect to the total amount of the aqueous dispersion, the water-dispersible polyisocyanate (solid content) is, for example, 1% by mass or more, preferably 5% by mass or more. Also, with respect to the total amount of the aqueous dispersion, the water-dispersible polyisocyanate (solid content) is, for example, 30% by mass or less, preferably 20% by mass or less.

[0185] In addition, when an aqueous dispersion of an active hydrogen group-containing compound is prepared, the aqueous dispersion of the water-dispersible polyisocyanate may not be prepared. That is, the solid content of the water-dispersible polyisocyanate can be used as it is.

[0186] Also, when an aqueous dispersion of the water-dispersible polyisocyanate is prepared, the aqueous dispersion of the active hydrogen group-containing compound may not be prepared. That is, the solid content of the active hydrogen group-containing compound can be used as it is.

[0187] In addition, the aqueous polyurethane resin composition can contain additives. Examples of the additives include catalysts, solvents, epoxy resins, coating property improvers, leveling agents, defoaming agents, antioxidants, ultraviolet absorbers, thickeners, anti-settling agents, plasticizers, surfactants, pigments, fungicides, fillers, organic particles, and inorganic particles. The additives may be blended in the main agent. Also, the additives may be blended in the curing agent.

[0188] Note that the blending amount of the additives is appropriately set according to the purpose and application.

[0189] When using the two-component curable polyurethane resin composition, the main agent and the curing agent are blended.

[0190] The blending ratio of the main agent and the curing agent is adjusted, for example, based on the equivalent ratio of the isocyanate group of the water-dispersible polyisocyanate to the active hydrogen group of the active hydrogen group-containing compound (isocyanate group / hydroxyl group).

[0191] More specifically, the equivalent ratio of the isocyanate groups of the water-dispersible polyisocyanate to the active hydrogen groups of the active hydrogen group-containing compound (isocyanate groups / active hydrogen groups) is, for example, 0.1 or more, preferably 0.5 or more. Further, the equivalent ratio of the isocyanate groups of the water-dispersible polyisocyanate to the active hydrogen groups of the active hydrogen group-containing compound (isocyanate groups / active hydrogen groups) is, for example, 5 or less, preferably 3 or less.

[0192] Then, the mixture of the main agent and the curing agent is applied to any object to be coated by a known coating method and dried under any drying conditions. Examples of the coating method include spray coating, dip coating, spin coating, rotary atomization coating, and curtain coating.

[0193] Thereby, a coating film of the aqueous polyurethane resin composition is formed. Thereafter, the coating film is cured by heating.

[0194] The heating conditions are appropriately set according to the main agent and the curing agent. For example, when the isocyanate groups of the curing agent are not blocked by a blocking agent, the heating temperature is, for example, 60°C or higher, preferably 80°C or higher. Further, the heating temperature is, for example, 150°C or lower, preferably 130°C or lower. Further, the heating time is, for example, 1 minute or longer, preferably 5 minutes or longer. Further, the heating time is, for example, 24 hours or shorter, preferably 12 hours or shorter.

[0195] Thereby, a polyurethane resin is obtained as a cured product composed of the aqueous polyurethane resin composition. Further, an article including the object to be coated and the polyurethane layer is obtained. More specifically, the article includes the object to be coated and a polyurethane layer disposed on the surface of the object to be coated, and the polyurethane layer includes the cured coating film of the above aqueous polyurethane resin composition. Further, the polyurethane resin is cured under any conditions as required.

[0196] In addition, when the isocyanate groups of the water-dispersible polyisocyanate are blocked by a blocking agent, the aqueous polyurethane resin composition is preferably a one-component curable polyurethane resin composition. In such a case, the mixing ratio of the water-dispersible polyisocyanate and the active hydrogen group-containing compound is the same as the mixing ratio of the water-dispersible polyisocyanate and the active hydrogen group-containing compound in the above two-component curable polyurethane resin composition.

[0197] And the above aqueous polyurethane resin composition contains the above water-dispersible polyisocyanate. Therefore, the above aqueous polyurethane resin composition can obtain a polyurethane resin with excellent hardness and also has excellent curability.

[0198] In addition, since the above article contains a cured coating film of the above aqueous polyurethane resin composition, it has excellent productivity.

[0199] Therefore, the above water-dispersible polyisocyanate, aqueous polyurethane resin composition and article are preferably used, for example, in automotive exterior finishes, surface resin coatings of household electrical appliances, and flexible packaging flexographic inks.

Examples

[0200] Examples are shown below to more specifically explain the present invention, but the present invention is not limited thereto. Specific numerical values such as the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "hereinafter" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding compounding ratio (content ratio), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention". In addition, "parts" and "%" are based on mass unless otherwise specified.

[0201] Synthesis Example 1 (Preparation of Polyisocyanate A) Into a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a nitrogen inlet tube, 2000.0 g of 1,5-pentamethylene diisocyanate (1,5-PDI, manufactured by Mitsui Chemicals, Inc.) and 3.2 g of isobutanol were charged. These were subjected to a urethanization reaction at 80 °C for 2 hours. The equivalent ratio (NCO / OH) of the isocyanate groups of 1,5-PDI to the hydroxyl groups of isobutanol was 600.

[0202] Next, 0.52 g of DABCO-TMR (N-(2-hydroxypropyl)-N,N,N-trimethylammonium-2-ethylhexanoate, manufactured by Air Products) was added to the obtained reaction solution as an isocyanuration catalyst, and the reaction was carried out at 80 to 86 °C for 2 hours.

[0203] Then, it was confirmed by measuring the isocyanate group content that 10% of the isocyanate groups had been converted. Thereafter, 0.60 g of o-toluenesulfonic acid was added to the reaction solution to stop the reaction.

[0204] The reaction solution was distilled using a thin-film distillation apparatus (vacuum degree 0.05 kPa, temperature 140 °C) to remove unreacted 1,5-PDI. Thereafter, the remaining components were dissolved in propylene glycol methyl ether acetate (PMA) so that the solid content concentration became 75.0% by mass. Thereby, polyisocyanate A was obtained.

[0205] The isocyanate group content (NCO%) of this polyisocyanate A was 18.5%.

[0206] In addition, polyisocyanate A was measured by gel permeation chromatography described below. As a result, it was confirmed that polyisocyanate A contained an isocyanurate derivative. Also, polyisocyanate A did not contain an allophanate derivative. That is, the content of the isocyanurate derivative with respect to the total amount of the allophanate derivative and the isocyanurate derivative was 100% by mass.

[0207] Synthesis Example 2 (Preparation of Polyisocyanate B) 2000.0 g of 1,5-pentamethylene diisocyanate and 26.3 g of isobutanol were used. Except for the above, polyisocyanate B was obtained in the same manner as in Synthesis Example 1. The equivalent ratio (NCO / OH) of the isocyanate group of 1,5-PDI to the hydroxyl group of isobutanol was 73.

[0208] The isocyanate group content (NCO%) of this polyisocyanate B was 13.5%. Also, the content ratio of the isocyanurate derivative to the total amount of the allophanate derivative and the isocyanurate derivative was 50% by mass.

[0209] Synthesis Example 3 (Preparation of Polyisocyanate C) 2000.0 g of 1,5-pentamethylene diisocyanate and 241.6 g of lauryl alcohol were used. Except for the above, polyisocyanate C was obtained in the same manner as in Synthesis Example 1. The equivalent ratio (NCO / OH) of the isocyanate group of 1,5-PDI to the hydroxyl group of lauryl alcohol was 20.

[0210] The isocyanate group content (NCO%) of this polyisocyanate C was 13.5%. Also, the content ratio of the isocyanurate derivative to the total amount of the allophanate derivative and the isocyanurate derivative was 50% by mass.

[0211] Synthesis Example 4 (Preparation of Polyisocyanate D) 2000.0 g of 1,3-bis(isocyanatomethyl)cyclohexane (1,3-H6XDI) and 76.4 g of isobutanol were used. Except for the above, polyisocyanate D was obtained in the same manner as in Synthesis Example 1. The equivalent ratio (NCO / OH) of the isocyanate group of 1,3-H6XDI to the hydroxyl group of isobutanol was 20.

[0212] The isocyanate group content (NCO%) of this polyisocyanate D was 13.5%. Also, the content ratio of the isocyanurate derivative to the total amount of the allophanate derivative and the isocyanurate derivative was 50% by mass.

[0213] Synthesis Example 5 (Preparation of Polyisocyanate E) Commercially available VESTANAT T-1890 (isocyanurate derivative of isophorone diisocyanate, manufactured by Evonik) was prepared. This was used as Polyisocyanate E.

[0214] Synthesis Example 6 (Preparation of Polyisocyanate F) 2000.0 g of hexamethylene diisocyanate and 2.9 g of isobutanol were used. Except for the above, Polyisocyanate G was obtained in the same manner as in Synthesis Example 1. The equivalent ratio (NCO / OH) of the isocyanate group of hexamethylene diisocyanate to the hydroxyl group of isobutanol was 600.

[0215] The isocyanate group content (NCO%) of this Polyisocyanate F was 17.1%.

[0216] <Gel Permeation Chromatography (GPC)> The molecular weight distribution of each polyisocyanate was measured with the following GPC apparatus.

[0217] And the area ratio of the peak corresponding to the allophanate derivative to all the peaks was taken as the content rate of the allophanate derivative. Also, the remaining ratio was taken as the content rate of the isocyanurate derivative.

[0218] Note that the peak having a top in the molecular weight range of 330 to 430 is the peak corresponding to the allophanate derivative.

[0219] GPC Apparatus: Equipment used: HLC-8020 (manufactured by Tosoh) Columns used: G1000HXL, G2000HXL, and G3000HXL (the above are product names of Tosoh) were connected in series Sample concentration: 0.3 mass%, tetrahydrofuran solution Sample injection volume: 100 μL Eluent: Tetrahydrofuran Flow rate of eluent: 0.8 ml / min Column temperature: 40 °C Detection method: differential refractive index Standard substance: polyethylene oxide (manufactured by Tosoh Corporation, trade name: TSK standard polyethylene oxide) Production Examples 1 to 6 Using the formulations shown in Table 1, the first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate were obtained.

[0220] More specifically, the first polyisocyanate or the second polyisocyanate and the hydrophilic active hydrogen component were mixed and reacted at 80 to 90 °C for 8 hours under dry nitrogen. Thereafter, a neutralizing agent was added, and further a solvent was added to adjust the solid content concentration.

[0221] <Acid value (mgKOH / g)> The acid value was measured in accordance with JIS K 1557-5 (2007).

[0222] <Content ratio of sulfone group (SO3 content, mass%)> SO3 - Assuming the molecular weight of is 80, the content ratio (SO3 content rate) of the sulfone group was calculated from the chemical structural formula and the formulation.

[0223] <Content ratio of isocyanate group (NCO content, mass%)> The content ratio of the isocyanate group was measured by the n-dibutylamine method in accordance with JIS K-1556 (2006) using a potentiometric titrator.

[0224] Examples 1 to 7 and Comparative Examples 1 to 2 Using the formulations shown in Table 2, the first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate obtained in each production example were blended to obtain a water-dispersible polyisocyanate. In Comparative Example 1, the first water-dispersible polyisocyanate was used alone.

[0225] <Evaluation> (1) Water dispersibility 5 g of the solid content of the water-dispersible polyisocyanate was added to 95 g of water, stirred with a magnetic stirrer for 15 minutes, and then allowed to stand for 1 hour. Then, the properties of the mixed solution were evaluated according to the following evaluation criteria.

[0226] ○: No precipitate.

[0227] △: There is a precipitate, but it can be redispersed by stirring.

[0228] ×: There is a precipitate and it cannot be redispersed.

[0229] (2) Pot life An aqueous acrylic emulsion with a hydroxyl value of 100 mg KOH / g (solid content concentration: 40.0 mass%) was diluted with water to a solid content concentration of 25 mass%. This aqueous solution was used as the main agent.

[0230] Each water-dispersible polyisocyanate as a curing agent was added to the above main agent and stirred for 15 minutes. The equivalent ratio of the isocyanate group in the curing agent to the hydroxyl group in the main agent (NCO / OH) was set to 1.0.

[0231] Thereafter, the mixed solution of the main agent and the curing agent was allowed to stand at 23°C for 20 hours. Then, the state of the mixed solution was evaluated according to the following evaluation criteria. ○: No precipitate.

[0232] △: There is a precipitate, but it can be redispersed by stirring.

[0233] ×: There is a precipitate and it cannot be redispersed.

[0234] (3) Curability An aqueous acrylic emulsion with a hydroxyl value of 50 mg KOH / g (solid content concentration: 40.0 mass%) was diluted with water to a solid content concentration of 25 mass%. This aqueous solution was used as the main agent.

[0235] Each water-dispersible polyisocyanate as a curing agent was added to the above-mentioned main agent and stirred for 15 minutes. The equivalent ratio of the isocyanate groups in the curing agent to the hydroxyl groups in the main agent (NCO / OH) was set to 1.0.

[0236] Thereafter, the mixed solution of the main agent and the curing agent was applied onto a glass plate. The coating amount was adjusted so that the dry thickness would be 20 μm. Thereafter, the coating film was dried at 70 °C for 30 minutes and cured at 23 °C for 7 days. Thereby, a cured film was obtained.

[0237] The cured film was immersed in a mixed solution of acetone and methanol (mass ratio 1:1) for 24 hours.

[0238] Then, the residual rate of the cured film after immersion was calculated and evaluated according to the following evaluation criteria.

[0239] ○: Residual rate 90% or more ×: Residual rate less than 90%

Table 1

Table 2

[0240] H6XDI: 1,3-bis(isocyanatomethyl)cyclohexane, Takenate 600, manufactured by Mitsui Chemicals, Inc. HDI: 1,6-hexamethylene diisocyanate PDI: 1,5-pentamethylene diisocyanate IPDI: Isophorone diisocyanate CAPS: 3-(cyclohexylamino)-propanesulfonic acid, a sulfone group-containing active hydrogen compound DMCHA: N,N-dimethylcyclohexylamine PMA: Propylene glycol methyl ether acetate

[0241] The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be construed restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the following claims.

Industrial Applicability

[0242] The water-dispersible polyisocyanate, aqueous polyurethane resin composition, and article of the present invention are suitably used, for example, in automotive exterior finishes, surface resin coatings for household electrical appliances, and flexible packaging flexographic inks.

Claims

1. A water-dispersible polyisocyanate containing isocyanate groups and sulfone groups, comprising a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component, wherein the polyisocyanate component comprises a first polyisocyanate containing pentamethylene diisocyanate, and a second polyisocyanate containing a polyisocyanate having 6 or more carbon atoms and the hydrophilic active hydrogen component comprises a sulfone group-containing active hydrogen compound, the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less based on the total amount of the first polyisocyanate and the second polyisocyanate, the first polyisocyanate contains an isocyanurate derivative of pentamethylene diisocyanate, the isocyanurate derivative of pentamethylene diisocyanate contains a reaction product of a pentamethylene diisocyanate monomer and an alcohol, and the alcohol contains a monool having 2 to 4 carbon atoms, a water-dispersible polyisocyanate.

2. The water-dispersible polyisocyanate according to claim 1, wherein the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is 60% by mass or more based on the total amount of the first polyisocyanate.

3. The second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms, and the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is 25% by mass or more and 75% by mass or less based on the total amount of the second polyisocyanate, the water-dispersible polyisocyanate according to claim 1.

4. The water-dispersible polyisocyanate according to claim 1, wherein the content ratio of the sulfone group is 0.2% by mass or more and 5% by mass or less based on the total amount of the water-dispersible polyisocyanate.

5. The water-dispersible polyisocyanate according to claim 1, wherein the isocyanate groups of the water-dispersible polyisocyanate are blocked by a blocking agent.

6. A water-based polyurethane resin composition comprising the water-dispersible polyisocyanate according to claim 1 and a compound containing an active hydrogen group.

7. An article comprising an object to be coated and a polyurethane layer disposed on the surface of the object to be coated, wherein the polyurethane layer contains a cured product of the water-based polyurethane resin composition according to claim 6.

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