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

Abstract

The water-dispersible polyisocyanate contains isocyanate groups and sulfonic groups. The water-dispersible polyisocyanate comprises a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component comprises a first polyisocyanate and a second polyisocyanate. The first polyisocyanate contains pentamethylene diisocyanate, and the second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component contains a sulfonic group-containing active hydrogen compound. The content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less relative to the total amount of the first polyisocyanate and the second polyisocyanate.

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, in the form of an organic solvent solution. In recent years, in order to achieve improvements in environmental performance and workability, it has been required to prepare the polyisocyanate component in the form of an aqueous dispersion. That is, a polyisocyanate component that can be dispersed in water is required.

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

[0005] The above polyisocyanate mixture can be water-dispersed due to the sulfone group of 3-(cyclohexylamino)propanesulfonic acid. In addition, a polyurethane resin can be obtained by the reaction of the above polyisocyanate mixture and a polyol component. Such a polyisocyanate mixture and polyurethane resin have excellent curability.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-513239 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, when pentamethylene-1,5-diisocyanate and / or its derivative is water-dispersed using a sulfone group, the pot life is insufficient.

[0011] The present invention provides a water-dispersible polyisocyanate, an aqueous polyurethane resin composition, and an article having excellent curability, water-dispersibility, and pot life.

[0012] Means for Solving the Problems

[0013] The present invention [1] includes a water-dispersible polyisocyanate, which is a water-dispersible polyisocyanate containing an isocyanate group and a sulfo group. The water-dispersible polyisocyanate comprises a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The aforementioned polyisocyanate component includes a first polyisocyanate and a second polyisocyanate. The first polyisocyanate contains pentamethylene diisocyanate, and the second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms. The aforementioned hydrophilic active hydrogen component includes a sulfo group-containing active hydrogen compound. With respect to the total amount of the aforementioned first polyisocyanate and the aforementioned second polyisocyanate, the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less.

[0014] The present invention [2] includes the water-dispersible polyisocyanate described in the above [1], wherein the aforementioned first polyisocyanate contains an isocyanurate derivative of pentamethylene diisocyanate, and with respect to the total amount of the aforementioned first polyisocyanate, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is 60% by mass or more.

[0015] The present invention [3] includes the water-dispersible polyisocyanate described in the above [2], wherein the aforementioned isocyanurate derivative of pentamethylene diisocyanate contains a reaction product of pentamethylene diisocyanate monomer and an alcohol.

[0016] The present invention [4] includes the water-dispersible polyisocyanate described in the above [3], wherein the aforementioned alcohol includes a monohydric alcohol.

[0017] The present invention [5] includes the water-dispersible polyisocyanate described in any one of the above [1] to [4], wherein the aforementioned second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms, and with respect to the total amount of the aforementioned second polyisocyanate, 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.

[0018] The present invention [6] includes the water-dispersible polyisocyanate described in any one of the above [1] to [5], wherein with respect to the total amount of the aforementioned water-dispersible polyisocyanate, the content ratio of the aforementioned sulfo group is 0.2% by mass or more and 5% by mass or less.

[0019] The present invention [7] includes the water-dispersible polyisocyanate described in any one of the above [1] to [6], wherein the aforementioned isocyanate group of the water-dispersible polyisocyanate is blocked with a blocking agent.

[0020] The present invention [8] includes an aqueous polyurethane resin composition, which comprises: the water-dispersible polyisocyanate described in any one of the above [1] to [7]; and a compound containing an active hydrogen group.

[0021] The present invention [9] includes an article having an object to be coated and a polyurethane layer disposed on the surface of the object to be coated, and the polyurethane layer contains a cured product of the aqueous polyurethane resin composition described in the above [8].

[0022] Advantages of the Invention

[0023] The aqueous polyisocyanate of the present invention contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component contains a first polyisocyanate and a second polyisocyanate. The first polyisocyanate contains pentamethylene diisocyanate, and the second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component contains a sulfonic group-containing active hydrogen compound.

[0024] Moreover, 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 aqueous polyisocyanate of the present invention has excellent curability, water dispersibility, and pot life.

[0025] In addition, the aqueous polyurethane resin composition of the present invention contains the above aqueous polyisocyanate. Therefore, the aqueous polyurethane resin composition of the present invention has excellent curability, water dispersibility, and pot life.

[0026] The article of the present invention contains a cured coating film of the above aqueous polyurethane resin composition, and thus has excellent productivity. Detailed Description of the Invention

[0027] The aqueous polyisocyanate of the present invention contains an isocyanate group and a sulfonic group. In addition, the aqueous polyisocyanate is a polyisocyanate capable of being water-dispersed. Moreover, the aqueous polyisocyanate contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component.

[0028] The polyisocyanate component contains a first polyisocyanate and a second polyisocyanate.

[0029] The first polyisocyanate contains pentamethylene diisocyanate. The first polyisocyanate is preferably composed of pentamethylene diisocyanate. Pentamethylene diisocyanate means a pentamethylene diisocyanate monomer and / or its derivative. It should be noted that hereinafter, a derivative of the pentamethylene diisocyanate monomer is referred to as a pentamethylene diisocyanate derivative.

[0030] As the pentamethylene diisocyanate monomer, 1,5-pentane diisocyanate (1,5-pentane diisocyanate) and its structural isomers can be cited. As the structural isomers, for example, 1,4-pentane diisocyanate (1,4-pentane diisocyanate), 1,3-pentane diisocyanate (1,3-pentane diisocyanate), and 1,2-pentane diisocyanate (1,2-pentane diisocyanate) can be cited. These pentamethylene diisocyanate monomers can be used alone or in combination of two or more. As the pentamethylene diisocyanate monomer, 1,5-pentane diisocyanate is preferably cited. It should be noted that the pentamethylene diisocyanate monomer can be produced, for example, according to the description in International Publication No. 2012 / 121291.

[0031] As the pentamethylene diisocyanate derivative, derivatives obtained by modifying the pentamethylene diisocyanate monomer by known methods can be cited. More specifically, as the pentamethylene diisocyanate derivative, for example, polymers, urethane derivatives, polyol derivatives, biuret derivatives, urea derivatives, oxadiazinetrione derivatives, and carbodiimide derivatives can be cited. In addition, as the polymer, for example, isocyanurate derivatives and iminooxadiazinedione derivatives can be cited. These pentamethylene diisocyanate derivatives can be used alone or in combination of two or more.

[0032] The pentamethylene diisocyanate can be used alone or in combination of two or more. As the pentamethylene diisocyanate, the pentamethylene diisocyanate derivative is preferably cited, and the isocyanurate derivative of the pentamethylene diisocyanate is more preferably cited. In other words, the first polyisocyanate preferably contains the isocyanurate derivative of the pentamethylene diisocyanate.

[0033] As the isocyanurate derivative of the pentamethylene diisocyanate, for example, the reaction product of the pentamethylene diisocyanate monomer and an alcohol can be cited.

[0034] More specifically, the isocyanurate derivative of the pentamethylene diisocyanate is produced, for example, by the following method. That is, in this method, first, the pentamethylene diisocyanate monomer is reacted with an alcohol.

[0035] As the alcohol, for example, monohydric alcohols, diols, and triols can be cited.

[0036] As the monohydric alcohol, for example, linear monohydric alcohols and branched monohydric alcohols can be cited.

[0037] As linear monohydric alcohols, examples 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. They can be used alone or in combination of two or more.

[0038] As branched-chain monohydric alcohols, examples include isopropanol, isobutanol (isobutyl alcohol), sec-butanol, tert-butanol, isopentanol, isohexanol, isoheptanol, isooctanol, 2-ethylhexane-1-ol, isononanol, isodecanol, 5-ethyl-2-nonanol, trimethylnonanol, 2-hexyldecanol, 3,9-diethyl-6-tridecanol, 2-isopropylisoundecanol, and 2-octyldodecanol. They can be used alone or in combination of two or more. These monohydric alcohols can be used alone or in combination of two or more.

[0039] As diols, examples include linear dihydric alcohols and branched-chain dihydric alcohols.

[0040] As linear dihydric alcohols, examples include linear alkane diols. As linear alkane diols, examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol (butylene glycol), 1,5-pentanediol, 1,6-hexanediol, 1,4-dihydroxy-2-butene, diethylene glycol, triethylene glycol, and dipropylene glycol. They can be used alone or in combination of two or more.

[0041] As branched-chain dihydric alcohols, examples include branched-chain alkane diols. As branched-chain alkane diols, examples include 1,2-propanediol, 1,3-butanediol, 1,2-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dihydroxymethylheptane, and 2,6-dimethyl-1-octene-3,8-diol. They can be used alone or in combination of two or more.

[0042] These diols can be used alone or in combination of two or more.

[0043] As triols, examples include glycerol, trimethylolpropane, and triisopropanolamine. They can be used alone or in combination of two or more.

[0044] These triols can be used alone or in combination of two or more.

[0045] These alcohols can be used alone or in combination of two or more.

[0046] The number of carbon atoms of the alcohol is, for example, 1 or more, preferably 2 or more. In addition, the number of carbon atoms of the alcohol is, for example, 50 or less, preferably 40 or less, more preferably 30 or less, further preferably 20 or less, still further preferably 10 or less, and particularly preferably 4 or less.

[0047] 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.

[0048] As the alcohol, a monohydric alcohol is preferably used, a branched monohydric alcohol is more preferably used, and isobutanol is further preferably used. By using these components, the water dispersibility of the water-dispersible polyisocyanate can be improved.

[0049] The mixing ratio of the pentamethylene diisocyanate monomer and the alcohol can be appropriately set within the range that does not hinder the excellent effects of the present invention.

[0050] 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, higher than 1, preferably 5 or more, more preferably 10 or more. In addition, 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, and further preferably 100 or less.

[0051] In addition, with respect to 100 parts by mass of the pentamethylene diisocyanate monomer, 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. In addition, with respect to 100 parts by mass of the pentamethylene diisocyanate monomer, 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.

[0052] The reaction conditions of the pentamethylene diisocyanate monomer and the alcohol can be appropriately set within the range that does not hinder the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. In addition, the reaction temperature is, for example, 20°C or higher, preferably 40°C or higher. In addition, the reaction temperature is, for example, 100°C or lower, preferably 90°C or lower. In addition, the reaction time is, for example, 0.05 hours or more, preferably 0.2 hours or more.

[0053] In addition, the reaction time is, for example, 10 hours or less, preferably 6 hours or less.

[0054] In addition, in this method, according to needs, a carbamate esterification catalyst can be incorporated into the pentamethylene diisocyanate monomer and the alcohol. Examples of the carbamate esterification catalyst include known amines and known organometallic compounds. It should be noted that the mixing ratio of the carbamate esterification catalyst is not particularly limited and can be appropriately set according to the purpose and use.

[0055] Thereby, the pentamethylene diisocyanate monomer and the alcohol undergo a carbamate esterification reaction. As a result, a carbamate esterification reaction product is obtained.

[0056] Next, in this method, the carbamate esterification reaction product is subjected to a urethane carbamate esterification reaction and an isocyanurate esterification reaction.

[0057] More specifically, in this method, an isocyanurate esterification catalyst is incorporated into the carbamate esterification reaction product and heating is carried out.

[0058] As the isocyanurate esterification catalyst, as long as it is a catalyst that can promote the urethane carbamate esterification and isocyanurate esterification of isocyanate groups, there is no particular limitation. Examples of the isocyanurate esterification catalyst include tertiary amines, Mannich bases, Friedel-Crafts catalysts, metal salts of alkyl carboxylic acids, organometallic compounds, halogenated organophosphorus compounds, hydroxides of tetraalkylammonium, organic weak acid salts of tetraalkylammonium, hydroxides of trialkylhydroxyalkylammonium, and organic weak acid salts of trialkylhydroxyalkylammonium. They can be used alone or in combination of two or more.

[0059] As the isocyanurate esterification catalyst, an organic weak acid salt of trialkylhydroxyalkylammonium is preferably cited.

[0060] Examples of the trialkylhydroxyalkylammonium include N-(2-hydroxypropyl)-N,N,N-trimethylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium. They can be used alone or in combination of two or more.

[0061] In addition, examples of the organic weak acid salt include acetate, propionate, 2-ethylhexanoate, octanoate, decanoate, myristate, and benzoate. They can be used alone or in combination of two or more.

[0062] With respect to 100 parts by mass of the pentamethylene diisocyanate monomer, the mixing ratio of the isocyanurate esterification catalyst is, for example, 0.0005 part by mass or more, preferably 0.001 part by mass or more. In addition, with respect to 100 parts by mass of the pentamethylene diisocyanate monomer, the mixing ratio of the isocyanurate esterification catalyst is, for example, 0.3 part by mass or less, preferably 0.05 part by mass or less, more preferably 0.03 part by mass or less.

[0063] The reaction conditions for the urethane carbamate esterification reaction and the isocyanurate esterification reaction can be appropriately set within a range that does not hinder the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. In addition, the reaction temperature is, for example, 0 °C or higher, preferably 20 °C or higher. In addition, the reaction temperature is, for example, 160 °C or lower, preferably 120 °C or lower. In addition, the reaction time is, for example, 30 minutes or longer, preferably 60 minutes or longer.

[0064] In addition, the reaction time is, for example, 20 hours or shorter, preferably 10 hours or shorter.

[0065] Then, at the time point when the reaction rate (isocyanate group conversion rate) of the reaction solution reaches a specified value, a reaction terminator is added to the reaction solution. The conversion rate of the isocyanate group when the reaction is stopped is, for example, 1% by mass or higher, preferably 5% by mass or higher. In addition, the conversion rate of the isocyanate group when the reaction is stopped is, for example, 20% by mass or lower, preferably 15% by mass or lower. It should be noted that the conversion rate of the isocyanate group can be calculated by a known method.

[0066] 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. They can be used alone or in combination of two or more. The mixing ratio of the reaction terminator can be appropriately set according to the purpose and use.

[0067] In addition, a catalyst adsorbent can be added instead of the reaction terminator. Examples of the catalyst adsorbent include chelating resins and ion exchange resins. They can be used alone or in combination of two or more. The mixing ratio of the catalyst adsorbent can be appropriately set according to the purpose and use.

[0068] Thereby, the urethane carbamate esterification reaction and the isocyanurate esterification reaction are stopped.

[0069] In addition, in each of the above reactions, a co-catalyst can be added. Examples of the co-catalyst include known organic phosphites. As the organic phosphite, preferably mono-phosphite esters are mentioned, and more preferably tris(tridecyl) phosphite is mentioned.

[0070] The mixing ratio of the co-catalyst is, for example, 0.01 part by mass or more, preferably 0.02 part by mass or more, more preferably 0.03 part by mass or more, relative to 100 parts by mass of the pentamethylene diisocyanate monomer. In addition, the mixing ratio of the co-catalyst is, for example, 0.2 part by mass or less, preferably 0.15 part by mass or less, more preferably 0.1 part by mass or less, relative to 100 parts by mass of the pentamethylene diisocyanate monomer.

[0071] In addition, in each of the above reactions, a reaction stabilizer can be added. As the reaction stabilizer, for example, known hindered phenol-based antioxidants can be cited. Preferably, 2,6-bis(tert-butyl)-4-methylphenol (BHT) can be cited.

[0072] With respect to 100 parts by mass of the pentamethylene diisocyanate monomer, the blending ratio of the reaction stabilizer is, for example, 0.01 part by mass or more, preferably 0.05 part by mass or more. In addition, with respect to 100 parts by mass of the pentamethylene diisocyanate monomer, the blending ratio of the reaction stabilizer is, for example, 1.0 part by mass or less, preferably 0.10 part by mass or less.

[0073] In addition, in each of the above reactions, a known reaction solvent can be added. It should be noted that the blending ratio of the reaction solvent can be appropriately set according to the purpose and use. In addition, in each of the above reactions, the reaction solution can be purified. As the purification method, for example, distillation and extraction can be cited. By purification, the unreacted pentamethylene diisocyanate monomer is removed from the reaction solution. In addition, the urethanization catalyst, isocyanuration catalyst, catalyst deactivator, cocatalyst, reaction stabilizer, and / or reaction solvent are removed together with the pentamethylene diisocyanate monomer.

[0074] Moreover, 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. Moreover, the reaction product is used as the first polyisocyanate.

[0075] In the first polyisocyanate, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate can be appropriately set according to the purpose and use. More specifically, with respect to the total amount of the first polyisocyanate, 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, further preferably 50% by mass or more, further preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0076] 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.

[0077] In addition, with respect to the total amount of the first polyisocyanate, the content ratio of the isocyanurate derivative of pentamethylene diisocyanate is, for example, 100% by mass or less. That is, the first polyisocyanate can be composed of the isocyanurate derivative of pentamethylene diisocyanate.

[0078] In addition, in the above reaction, depending on the reaction conditions, the pentamethylene diisocyanate monomer sometimes undergoes isocyanurate modification and urethane modification. As a result, the first polyisocyanate sometimes contains an isocyanurate derivative of pentamethylene diisocyanate and a urethane derivative of pentamethylene diisocyanate.

[0079] When the first polyisocyanate contains an isocyanurate derivative of pentamethylene diisocyanate and a urethane derivative of pentamethylene diisocyanate, their content ratios can be appropriately set according to the purpose and use.

[0080] In such a case, based on the total amount of the first polyisocyanate, 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, further preferably 50% by mass or more, further preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 75% by mass or more. In addition, based on the total amount of the first polyisocyanate, 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, and further preferably 80% by mass or less.

[0081] In addition, based on the total amount of the first polyisocyanate, the content ratio of the urethane 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, and further preferably 20% by mass or more. In addition, based on the total amount of the first polyisocyanate, the content ratio of the urethane 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, further preferably 50% by mass or less, further preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 25% by mass or less.

[0082] It should be noted that the content ratio of the isocyanurate derivative and the content ratio of the urethane derivative are determined by gel permeation chromatography according to the examples described below.

[0083] In addition, in the above method, an isocyanurate derivative of pentamethylene diisocyanate and a urethane derivative of pentamethylene diisocyanate are produced simultaneously, but for example, the isocyanurate derivative of pentamethylene diisocyanate and the urethane derivative of pentamethylene diisocyanate can be produced separately and mixed in the above ratios. In addition, an isocyanurate derivative of pentamethylene diisocyanate and / or a urethane derivative of pentamethylene diisocyanate can be further added to the above reaction product and adjusted to the above ratios.

[0084] In addition, the first polyisocyanate can be dissolved in known organic solvents. In such a case, the solid component concentration of the solution of the first polyisocyanate is, for example, 10% by mass or more, preferably 20% by mass or more. In addition, the solid component concentration of the solution of the first polyisocyanate is, for example, 90% by mass or less, preferably 80% by mass or less.

[0085] 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 means a polyisocyanate monomer having 6 or more carbon atoms and / or its derivative. It should be noted that hereinafter, the derivative of the polyisocyanate monomer having 6 or more carbon atoms is referred to as a polyisocyanate derivative having 6 or more carbon atoms.

[0086] 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.

[0087] Examples of the aliphatic polyisocyanate monomer having 6 or more carbon atoms include a hexamethylene diisocyanate monomer. They can be used alone or in combination of two or more.

[0088] Examples of the alicyclic polyisocyanate monomer having 6 or more carbon atoms include an isophorone diisocyanate monomer, a norbornene diisocyanate monomer, a bis(isocyanatomethyl)cyclohexane monomer, and a methylenebis(cyclohexyl isocyanate) monomer. They can be used alone or in combination of two or more.

[0089] Examples of the aromatic polyisocyanate monomer having 6 or more carbon atoms include toluene diisocyanate, naphthalene diisocyanate, and diphenylmethane diisocyanate. They can be used alone or in combination of two or more.

[0090] These polyisocyanate monomers having 6 or more carbon atoms can be used alone or in combination of two or more.

[0091] Examples of the polyisocyanate derivative having 6 or more carbon atoms include derivatives of the same types as described above.

[0092] As the polyisocyanate having 6 or more carbon atoms, preferably a polyisocyanate derivative having 6 or more carbon atoms can be mentioned, and more preferably an isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms can be mentioned. In other words, the second polyisocyanate preferably contains an isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms.

[0093] Isocyanurate derivatives of polyisocyanates having 6 or more carbon atoms can be produced by known methods. In addition, isocyanurate derivatives of polyisocyanates having 6 or more carbon atoms can also be produced, for example, by the same method as that for isocyanurate derivatives of pentamethylene diisocyanate.

[0094] 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 further preferably 50% by mass or more, based on the total amount of the second polyisocyanate.

[0095] 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.

[0096] In addition, the content ratio of the isocyanurate derivative of the polyisocyanate having 6 or more carbon atoms is, for example, 100% by mass or less based on the total amount of the second polyisocyanate. That is, the second polyisocyanate may consist of an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms.

[0097] In addition, the second polyisocyanate sometimes contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and a urethane carbonate derivative of a polyisocyanate having 6 or more carbon atoms.

[0098] Preferably, the second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and a urethane carbonate derivative of a polyisocyanate having 6 or more carbon atoms.

[0099] When the second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms and a urethane carbonate derivative of a polyisocyanate having 6 or more carbon atoms, their content ratios can be appropriately set according to the purpose and use.

[0100] 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, further preferably 30% by mass or more, and particularly preferably 40% by mass or more based on the total amount of the second polyisocyanate. In addition, 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, further preferably 80% by mass or less, further preferably 75% by mass or less, further preferably 70% by mass or less, and particularly preferably 60% by mass or less based on the total amount of the second polyisocyanate.

[0101] In addition, with respect to the total amount of the second polyisocyanate, the content ratio of the urethane-formate 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, further preferably 20% by mass or more, further preferably 25% by mass or more, further preferably 30% by mass or more, and particularly preferably 40% by mass or more. In addition, with respect to the total amount of the second polyisocyanate, the content ratio of the urethane-formate 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, further preferably 70% by mass or less, and particularly preferably 60% by mass or less.

[0102] In addition, the second polyisocyanate can 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. In addition, 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.

[0103] The polyisocyanate component only needs to contain the first polyisocyanate and the second polyisocyanate, and may also contain other polyisocyanates.

[0104] Preferably, the polyisocyanate component only contains the first polyisocyanate and the second polyisocyanate. That is, preferably, the polyisocyanate component consists of the first polyisocyanate and the second polyisocyanate.

[0105] With respect to the total amount of the first polyisocyanate and the second polyisocyanate, 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, further preferably 55% by mass or more, and particularly preferably 60% by mass or more. In addition, with respect to the total amount of the first polyisocyanate and the second polyisocyanate, 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, and further preferably 75% by mass or less.

[0106] With respect to the total amount of the first polyisocyanate and the second polyisocyanate, 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, and further preferably 25% by mass or more. In addition, with respect to the total amount of the first polyisocyanate and the second polyisocyanate, 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, further preferably 45% by mass or less, and particularly preferably 40% by mass or less.

[0107] 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.

[0108] In addition, the polyisocyanate component can 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. In addition, 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.

[0109] Then, the above polyisocyanate component is reacted with a hydrophilic active hydrogen component to obtain a water-dispersible polyisocyanate.

[0110] More specifically, in the preparation of the water-dispersible polyisocyanate, the polyisocyanate component is reacted with the hydrophilic active hydrogen component in a proportion such that free isocyanate groups remain.

[0111] There is no particular limitation on the method for producing the water-dispersible polyisocyanate.

[0112] For example, first, the first polyisocyanate and the second polyisocyanate are mixed in the above proportions to prepare a mixed polyisocyanate. Then, the mixed polyisocyanate is reacted with the hydrophilic active hydrogen component. Thus, a water-dispersible polyisocyanate can be obtained.

[0113] In addition, for example, first, the first polyisocyanate is reacted with the hydrophilic active hydrogen component to prepare a first water-dispersible polyisocyanate. In addition, the second polyisocyanate is reacted with the hydrophilic active hydrogen component 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 proportions of the first polyisocyanate and the second polyisocyanate are adjusted to be within the above ranges. Thus, a water-dispersible polyisocyanate can be obtained.

[0114] Preferably, first, the first polyisocyanate is reacted with the hydrophilic active hydrogen component to prepare a first water-dispersible polyisocyanate. In addition, the second polyisocyanate is reacted with the hydrophilic active hydrogen component to prepare a second water-dispersible polyisocyanate. Then, the first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate are mixed. Thus, a water-dispersible polyisocyanate is obtained.

[0115] The hydrophilic active hydrogen component contains a sulfonic group-containing active hydrogen compound.

[0116] The sulfonic group-containing active hydrogen compound is a compound containing one or more sulfonic groups and one or more active hydrogen groups. Examples of the active hydrogen group include a hydroxyl group and an amino group.

[0117] Examples of the sulfonic acid group-containing active hydrogen compound include compounds having one active hydrogen group and one sulfonic acid group. Examples of such sulfonic acid group-containing active hydrogen compounds include hydroxyalkanesulfonic acids and sulfamic acids.

[0118] Examples of the hydroxyalkanesulfonic acid include hydroxymethanesulfonic acid, hydroxyethanesulfonic acid, and 3-hydroxypropanesulfonic acid. They may be used alone or in combination of two or more.

[0119] Examples of the sulfamic acid include 2-(cyclohexylamino)ethanesulfonic acid (CHES) and 3-(cyclohexylamino)propanesulfonic acid (CAPS). They may be used alone or in combination of two or more.

[0120] These sulfonic acid group-containing active hydrogen compounds may be used alone or in combination of two or more.

[0121] Examples of the preferred sulfonic acid group-containing active hydrogen compound include sulfamic acid, and more preferably 3-(cyclohexylamino)propanesulfonic acid.

[0122] In addition, the hydrophilic active hydrogen component may contain other water-dispersible active hydrogen compounds as optional components.

[0123] The other water-dispersible active hydrogen compounds are water-dispersible active hydrogen compounds other than the sulfonic acid group-containing active hydrogen compounds.

[0124] More specifically, examples of the other water-dispersible active hydrogen compounds include active hydrogen compounds containing nonionic groups, active hydrogen compounds containing carboxyl groups, and active hydrogen compounds containing phosphate groups.

[0125] Examples of the active hydrogen compound containing a nonionic group include polyoxyethylene compounds.

[0126] 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 glycols and diols containing polyoxyethylene side chains.

[0127] Examples of the mono-terminally blocked polyoxyethylene glycol include alkoxypolyethylene glycols obtained by blocking one terminal with an alkyl group having 1 to 20 carbon atoms. More specifically, examples include methoxypolyoxyethylene glycol and ethoxypolyoxyethylene glycol. The mono-terminally blocked polyoxyethylene glycol can be produced by known methods.

[0128] Examples of the diol containing a polyoxyethylene side chain include reaction products of polyoxyethylene group-containing monoisocyanates and dialkanolamines. The diol containing a polyoxyethylene side chain can be produced by known methods.

[0129] The polyoxyethylene compound can be used alone or in combination of two or more kinds.

[0130] The number-average molecular weight of the polyoxyethylene compound is, for example, 200 or more, preferably 300 or more, and for example, 2000 or less, preferably 1000 or less.

[0131] The active hydrogen compound containing a carboxyl group is a compound having both an active hydrogen group and a carboxyl group. Examples of the active hydrogen compound containing a carboxyl group include, for example, an active hydrogen compound containing a carboxyl group having one active hydrogen group and one carboxyl group. In addition, examples of the active hydrogen compound containing a carboxyl group also include, for example, an active hydrogen compound containing a carboxyl group having two active hydrogen groups and one carboxyl group.

[0132] Examples of the active hydrogen compound containing a carboxyl group having one active hydrogen group and one carboxyl group include, for example, glycolic acid, lactic acid, hydroxypivalic acid, malic acid, and citric acid.

[0133] Examples of the active hydrogen compound containing a carboxyl group having two active hydrogen groups and one carboxyl group include, for example, 2,2-dihydroxymethylacetic acid, 2,2-dihydroxymethyllactic acid, 2,2-dihydroxy-2-methylpropionic acid, 2,2-dihydroxymethylbutyric acid, dihydroxymethylheptanoic acid, dihydroxymethylnonanoic acid, 2,2-dihydroxymethylbutyric acid, and 2,2-dihydroxymethylvaleric acid.

[0134] The active hydrogen compound containing a carboxyl group can be used alone or in combination of two or more kinds.

[0135] The active hydrogen compound containing a phosphoric acid group is a compound having both an active hydrogen group and a phosphoric acid group.

[0136] Examples of the active hydrogen compound containing a phosphoric acid group include, for example, an active hydrogen compound containing a phosphoric acid group having one active hydrogen group and one phosphoric acid group.

[0137] Examples of such an active hydrogen compound containing a phosphoric acid group include, for example, hydroxyalkylphosphonic acid and aminoalkylphosphonic acid.

[0138] The active hydrogen compound containing a phosphoric acid group can be used alone or in combination of two or more kinds.

[0139] Other water-dispersible active hydrogen compounds can be used alone or in combination of two or more kinds.

[0140] 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, further preferably 30% by mass or less, further preferably 10% by mass or less, and particularly preferably 0% by mass, based on the total amount of the hydrophilic active hydrogen component.

[0141] That is, the hydrophilic active hydrogen component is particularly preferably composed of a sulfonic group-containing active hydrogen compound and does not contain other water-dispersible active hydrogen compounds.

[0142] In the case where the hydrophilic active hydrogen component is composed of a sulfonic group-containing active hydrogen compound, a water-dispersible polyisocyanate can be obtained which can give a polyurethane resin having particularly excellent hardness and mechanical properties and has excellent curability and water dispersibility.

[0143] The reaction ratio of the first polyisocyanate and the hydrophilic active hydrogen component is adjusted so that free isocyanate groups remain in the reaction product.

[0144] More specifically, the equivalent ratio (active hydrogen group / NCO) of the active hydrogen groups of the hydrophilic active hydrogen component to the isocyanate groups of the first polyisocyanate is, for example, 0.30 or less, preferably 0.20 or less. In addition, the equivalent ratio (active hydrogen group / NCO) of the active hydrogen groups of the hydrophilic active hydrogen component to the isocyanate groups of the first polyisocyanate is, for example, 0.01 or more, preferably 0.10 or more.

[0145] The blending 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, relative to 100 parts by mass of the first polyisocyanate. In addition, the blending 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, relative to 100 parts by mass of the first polyisocyanate.

[0146] The reaction conditions of the first polyisocyanate and the hydrophilic active hydrogen component can be appropriately set within a range that does not hinder the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. In addition, the reaction temperature is, for example, 50°C or higher, preferably 70°C or higher. In addition, the reaction temperature is, for example, 150°C or lower, preferably 110°C or lower. In addition, the reaction time is, for example, 0.5 hours or more, preferably 1 hour or more. In addition, the reaction time is, for example, 120 hours or lower, preferably 72 hours or lower.

[0147] It should be noted that the end of the reaction is confirmed, for example, based on the fact that the amount of isocyanate in the reaction solution does not change. The amount of isocyanate is measured by titration or infrared absorption method.

[0148] In addition, in this method, it is preferable to add a neutralizing agent to the reaction solution to form a salt of the sulfonic group. That is, the sulfonic group may not be a salt or may be a salt. Preferred examples of the sulfonic group include salts of the sulfonic group.

[0149] As the neutralizing agent, commonly used bases can be cited. As the base, specifically, organic bases and inorganic bases can be cited.

[0150] As the organic base, for example, tertiary amines and secondary amines can be mentioned. As the tertiary amines, for example, trialkylamines and alkanolamines can be mentioned. As the trialkylamines, for example, trimethylamine, triethylamine, and N,N-dimethylcyclohexylamine can be mentioned. As the alkanolamines, for example, dimethylethanolamine, methyldiethanolamine, triethanolamine, and triisopropanolamine can be mentioned. As the secondary amines, for example, heterocyclic amines can be mentioned. As the heterocyclic amines, for example, morpholine can be mentioned. These organic bases can be used alone or in combination of two or more.

[0151] As the inorganic base, for example, ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal carbonates can be mentioned. As the alkali metal hydroxides, for example, lithium hydroxide, sodium hydroxide, and potassium hydroxide can be mentioned. As the alkaline earth metal hydroxides, for example, magnesium hydroxide and calcium hydroxide can be mentioned. As the alkali metal carbonates, for example, sodium carbonate and potassium carbonate can be mentioned. These inorganic bases can be used alone or in combination of two or more.

[0152] These neutralizing agents can be used alone or in combination of two or more.

[0153] As the neutralizing agent, preferably, organic bases can be mentioned, more preferably, tertiary amines can be mentioned, further preferably, trialkylamines can be mentioned, and particularly preferably, N,N-dimethylcyclohexylamine can be mentioned.

[0154] With respect to 1 equivalent of the sulfo group, the addition amount of the neutralizing agent is, for example, 0.4 equivalent or more, preferably 0.6 equivalent or more. In addition, with respect to 1 equivalent of the sulfo group, the addition amount of the neutralizing agent is, for example, 1.2 equivalents or less, preferably 1.0 equivalent or less.

[0155] Thus, a first water-dispersible polyisocyanate containing an isocyanate group and a sulfo group is obtained.

[0156] In addition, in this method, the second water-dispersible polyisocyanate is prepared by operating in the same manner as the first water-dispersible polyisocyanate. That is, first, the second polyisocyanate and the 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.

[0157] Thus, a second water-dispersible polyisocyanate containing an isocyanate group and a sulfo group is obtained.

[0158] Then, in this method, the first water-dispersible polyisocyanate and the 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-mentioned range.

[0159] Thus, a water-dispersible polyisocyanate containing an isocyanate group and a sulfo group is obtained.

[0160] In addition, in the aqueous-dispersible polyisocyanate, the isocyanate group may be a free isocyanate group. In addition, the isocyanate group may also be blocked with a blocking agent. That is, examples of the isocyanate group include a free isocyanate group and a blocked isocyanate group.

[0161] The blocking agent is a compound having an active group reactive with the isocyanate group (hereinafter referred to as a blocking group). Examples of the blocking agent include, for example, 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, amide compounds, lactam compounds, imide compounds, triazole compounds, pyrazole compounds, mercaptan compounds, and bisulfites. They may 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.

[0162] Then, an aqueous-dispersible polyisocyanate having a free isocyanate group is reacted with the above-mentioned blocking agent to thereby produce an aqueous-dispersible polyisocyanate having a blocked isocyanate group.

[0163] The mixing ratio of the aqueous-dispersible polyisocyanate having a free isocyanate group and the above-mentioned blocking agent is adjusted, for example, based on the equivalent ratio of the isocyanate group in the aqueous-dispersible polyisocyanate and the blocking group in the blocking agent.

[0164] More specifically, the equivalent ratio of the blocking group to the free isocyanate group (blocking group / isocyanate group) is, for example, 0.2 or more, preferably 0.5 or more, more preferably 0.8 or more, and further preferably 1.0 or more. In addition, the equivalent ratio of the blocking group to the free isocyanate group (blocking group / isocyanate group) is, for example, 1.5 or less, preferably 1.2 or less, and more preferably 1.1 or less.

[0165] The reaction conditions of the aqueous-dispersible polyisocyanate having a free isocyanate group and the above-mentioned blocking agent can be appropriately set within a range that does not hinder the excellent effects of the present invention. More specifically, the environmental conditions are an inert atmosphere and normal pressure. In addition, the reaction temperature is, for example, 0°C or higher, preferably 20°C or higher. In addition, the reaction temperature is, for example, 100°C or lower, preferably 80°C or lower, and more preferably 70°C or lower. In addition, the reaction time is, for example, 0.5 hours or more, preferably 1.0 hours or more. In addition, the reaction time is, for example, 24 hours or less, preferably 12 hours or less.

[0166] It should be noted that the end of the reaction is confirmed, for example, based on the non-change in the amount of isocyanate in the reaction solution. The amount of isocyanate is measured by titration or infrared absorption method.

[0167] In addition, each of the above reactions can be carried out under solvent-free conditions. In addition, each of the above reactions can be carried out in the presence of a solvent. As the solvent, known organic solvents can be cited. In addition, the mixing ratio of the solvent can be appropriately set according to the purpose and use.

[0168] In addition, when using a solvent, the solvent can also be removed after the reaction. As the method for removing the solvent, distillation and extraction can be cited, for example.

[0169] It should be noted that hereinafter, the isocyanate group represents a free isocyanate group and an isocyanate group blocked with a blocking agent.

[0170] 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.

[0171] In addition, with respect to the total amount of the water-dispersible polyisocyanate, the content ratio of the isocyanate group is, for example, 5% by mass or more, preferably 7% by mass or more. In addition, with respect to the total amount of the water-dispersible polyisocyanate, 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.

[0172] In addition, with respect to the total amount of the water-dispersible polyisocyanate, the content ratio of the sulfo 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, further preferably 1% by mass or more. In addition, with respect to the total amount of the water-dispersible polyisocyanate, the content ratio of the sulfo group is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, further preferably 3% by mass or less.

[0173] If the content ratio of the sulfo group exceeds the above lower limit, particularly excellent water dispersibility can be obtained. In addition, if the content ratio of the sulfo group is lower than the above upper limit, particularly excellent water resistance can be obtained.

[0174] It should be noted that the content ratio of the sulfo group can be calculated from the chemical structural formula and the formulation according to the examples described later.

[0175] In addition, when the water-dispersible polyisocyanate contains an oxyethylene unit, with respect to the total amount of the water-dispersible polyisocyanate, its content ratio is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, further preferably 3% by mass or less.

[0176] It should be noted that the content ratio of oxyethylene units can be calculated from the chemical structural formula and the compounding formula according to the following examples.

[0177] In addition, 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. In addition, 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.

[0178] It should be noted that the acid value is measured in accordance with JIS K 1557-5(2007). In addition, the sulfonic group content of the water-dispersible polyisocyanate can also be calculated based on the input amount of the raw material components, and the acid value can be obtained therefrom.

[0179] If the acid value of the water-dispersible polyisocyanate exceeds the above lower limit, particularly excellent water dispersibility can be obtained. In addition, if the acid value of the water-dispersible polyisocyanate is lower than the above upper limit, particularly excellent water resistance can be obtained.

[0180] Moreover, the above water-dispersible polyisocyanate contains the reaction product of a polyisocyanate component and a hydrophilic active hydrogen component. The polyisocyanate component contains a first polyisocyanate and a second polyisocyanate. The first polyisocyanate contains pentamethylene diisocyanate, and the second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms. The hydrophilic active hydrogen component contains a sulfonic group-containing active hydrogen compound. Moreover, the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less relative to 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.

[0181] The aqueous polyurethane resin composition contains the above water-dispersible polyisocyanate and a compound containing an active hydrogen group. It should be noted that the aqueous polyurethane resin composition can be a one-component curable polyurethane resin composition formed by mixing the water-dispersible polyisocyanate and the compound containing an active hydrogen group. In addition, the polyurethane resin composition can also be a two-component curable polyurethane resin composition in which the water-dispersible polyisocyanate and the compound containing an active hydrogen group are separately prepared and compounded at the time of use.

[0182] The aqueous polyurethane resin composition is preferably a two-component curable polyurethane resin composition.

[0183] The two-component curable polyurethane resin composition contains a compound containing an active hydrogen group as the main agent. In addition, the two-component curable polyurethane resin composition contains the above water-dispersible polyisocyanate as the curing agent.

[0184] The main agent contains, for example, an aqueous dispersion of a compound containing an active hydrogen group.

[0185] Examples of the compound containing an active hydrogen group include macromolecular polyols. A macromolecular polyol is an organic compound (polymer) having a relatively high molecular weight and having two or more hydroxyl groups in the molecule. It should be noted that the number-average molecular weight of the macromolecular polyol is, for example, higher than 600 and, for example, 20,000 or less.

[0186] Examples of the macromolecular polyol include polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy group polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. They can be used alone or in combination of two or more.

[0187] These compounds containing an active hydrogen group can be used alone or in combination of two or more.

[0188] The aqueous dispersion of the compound containing an active hydrogen group can be prepared, for example, by adding water to the compound containing an active hydrogen group. Alternatively, the aqueous dispersion of the compound containing an active hydrogen group can also be prepared, for example, by adding the compound containing an active hydrogen group to water.

[0189] In the aqueous dispersion of the compound containing an active hydrogen group, the content ratio of the compound containing an active hydrogen group can be appropriately set according to the purpose and use. For example, relative to the total amount of the aqueous dispersion, the compound containing an active hydrogen group (solid component) is, for example, 1% by mass or more, preferably 5% by mass or more. In addition, relative to the total amount of the aqueous dispersion, the compound containing an active hydrogen group (solid component) is, for example, 30% by mass or less, preferably 20% by mass or less.

[0190] The curing agent contains, for example, an aqueous dispersion of a water-dispersible polyisocyanate.

[0191] The aqueous dispersion of the water-dispersible polyisocyanate can be prepared, for example, by adding water to the water-dispersible polyisocyanate. Alternatively, the aqueous dispersion of the water-dispersible polyisocyanate can also be prepared, for example, by adding the water-dispersible polyisocyanate to water. In addition, if necessary, a known external emulsifier can be added to water and / or the water-dispersible polyisocyanate. Alternatively, a known external emulsifier can also be added to a mixture of water and the water-dispersible polyisocyanate.

[0192] In the aqueous dispersion of the water-dispersible polyisocyanate, the content ratio of the water-dispersible polyisocyanate can be appropriately set according to the purpose and use. For example, relative to the total amount of the aqueous dispersion, the water-dispersible polyisocyanate (solid component) is, for example, 1% by mass or more, preferably 5% by mass or more. In addition, relative to the total amount of the aqueous dispersion, the water-dispersible polyisocyanate (solid component) is, for example, 30% by mass or less, preferably 20% by mass or less.

[0193] It should be noted that in the case where an aqueous dispersion of a compound having an active hydrogen group is prepared, it is also possible not to prepare an aqueous dispersion of the water-dispersible polyisocyanate. That is, the solid component of the water-dispersible polyisocyanate can be directly used.

[0194] In addition, in the case where an aqueous dispersion of the water-dispersible polyisocyanate is prepared, it is also possible not to prepare an aqueous dispersion of the compound having an active hydrogen group. That is, the solid component of the compound having an active hydrogen group can be directly used.

[0195] In addition, the aqueous polyurethane resin composition may 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, mildew-proof agents, fillers, organic particles, and inorganic particles. The additives can be incorporated into the main agent. In addition, the additives can also be incorporated into the curing agent.

[0196] It should be noted that the blending amount of the additives can be appropriately set according to their purpose and use.

[0197] When using the two-component curable polyurethane resin composition, the main agent and the curing agent are blended.

[0198] The blending ratio of the main agent and the curing agent is adjusted, for example, based on the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group of the water-dispersible polyisocyanate to the active hydrogen group of the compound having an active hydrogen group.

[0199] More specifically, the equivalent ratio (isocyanate group / active hydrogen group) of the isocyanate group of the water-dispersible polyisocyanate to the active hydrogen group of the compound having an active hydrogen group is, for example, 0.1 or more, preferably 0.5 or more. In addition, the equivalent ratio (isocyanate group / active hydrogen group) of the isocyanate group of the water-dispersible polyisocyanate to the active hydrogen group of the compound having an active hydrogen group is, for example, 5 or less, preferably 3 or less.

[0200] Then, a mixture of the main agent and the curing agent is applied to an arbitrary object to be coated using a known coating method, and dried under arbitrary drying conditions. Examples of the coating method include spray coating, dip coating, spin coating, rotary atomization coating, and curtain coating.

[0201] Thereby, a coating film of the aqueous polyurethane resin composition is formed. Then, the coating film is cured by heating.

[0202] The heating conditions can be appropriately set according to the main agent and the curing agent. For example, when the isocyanate group of the curing agent is not blocked with a blocking agent, the heating temperature is, for example, 60°C or higher, preferably 80°C or higher. In addition, the heating temperature is, for example, 150°C or lower, preferably 130°C or lower. In addition, the heating time is, for example, 1 minute or longer, preferably 5 minutes or longer. In addition, the heating time is, for example, 24 hours or shorter, preferably 12 hours or shorter.

[0203] Thereby, as a cured product formed from the aqueous polyurethane resin composition, a polyurethane resin is obtained. In addition, thereby, an article including the object to be coated and a 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 a cured coating film of the above aqueous polyurethane resin composition. In addition, the polyurethane resin can be cured under arbitrary conditions as needed.

[0204] In addition, when the isocyanate group of the water-dispersible polyisocyanate is blocked with 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 compound containing an active hydrogen group is the same as that in the above two-component curable polyurethane resin composition.

[0205] Moreover, the above aqueous polyurethane resin composition includes the above water-dispersible polyisocyanate. Therefore, the above aqueous polyurethane resin composition can obtain a polyurethane resin with excellent hardness and has excellent curability.

[0206] In addition, the above article includes a cured coating film of the above aqueous polyurethane resin composition, and thus has excellent productivity.

[0207] Therefore, the above water-dispersible polyisocyanate, aqueous polyurethane resin composition, and article can be preferably used in, for example, automotive exterior decoration, surface resin coatings of household electrical appliances, and flexible packaging flexographic inks.

[0208] Examples

[0209] Examples are shown below to illustrate the present invention more specifically, but the present invention is not limited thereto. The specific values of the compounding ratios (including ratios), physical property values, parameters, etc. used in the following description may be replaced with the upper limit values (values defined in the form of "below" or "less than") or lower limit values (values defined in the form of "above" or "more than") of the corresponding compounding ratios (including ratios), physical property values, parameters, etc. described in the above "Detailed Description". It should be noted that "parts" and "%" are based on mass unless otherwise specified.

[0210] Synthesis Example 1 (Preparation of Polyisocyanate A)

[0211] Into a four-necked flask equipped with a stirrer, thermometer, reflux tube, and nitrogen inlet tube, 2000.0 g of 1,5-pentanediisocyanate (1,5-PDI, manufactured by Mitsui Chemicals, Inc.) and 3.2 g of isobutanol were charged. The urethanization reaction was carried out at 80 °C for 2 hours. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate group of 1,5-PDI to the hydroxyl group of isobutanol was 600.

[0212] Next, 0.52 g of DABCO-TMR (N-(2-hydroxypropyl)-N,N,N-trimethylammonium 2-ethylhexanoate, manufactured by Air Products) as an isocyanuration catalyst was added to the obtained reaction solution, and the reaction was carried out at 80 - 86 °C for 2 hours.

[0213] Then, through the determination of the isocyanate group content, it was confirmed that 10% of the isocyanate group had been converted. Then, 0.60 g of o-toluenesulfonic acid was added to the reaction solution to stop the reaction.

[0214] 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. Then, the remaining components were dissolved in propylene glycol monomethyl ether acetate (PMA) so that the solid component concentration became 75.0 mass%. Thus, polyisocyanate A was obtained.

[0215] The isocyanate group content (NCO%) of this polyisocyanate A was 18.5%.

[0216] In addition, polyisocyanate A was measured by gel permeation chromatography described later. As a result, it was confirmed that polyisocyanate A contained an isocyanurate derivative. In addition, polyisocyanate A did not contain a urethane-formate derivative. That is, the content of the isocyanurate derivative relative to the total amount of the urethane-formate derivative and the isocyanurate derivative was 100 mass%.

[0217] Synthesis Example 2 (Preparation of Polyisocyanate B)

[0218] 1,5-Pentanediisocyanate (2000.0 g) and isobutanol (26.3 g) were used. Except for the above, the same operations as in Synthesis Example 1 were carried out to obtain polyisocyanate B. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate groups of 1,5-PDI to the hydroxyl groups of isobutanol was 73.

[0219] The isocyanate group content (NCO%) of this polyisocyanate B was 13.5%. In addition, the content ratio of the isocyanurate derivative to the total amount of the urethane-formate derivative and the isocyanurate derivative was 50% by mass.

[0220] Synthesis Example 3 (Preparation of Polyisocyanate C)

[0221] 1,5-Pentanediisocyanate (2000.0 g) and lauryl alcohol (241.6 g) were used. Except for the above, the same operations as in Synthesis Example 1 were carried out to obtain polyisocyanate C. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate groups of 1,5-PDI to the hydroxyl groups of lauryl alcohol was 20.

[0222] The isocyanate group content (NCO%) of this polyisocyanate C was 13.5%. In addition, the content ratio of the isocyanurate derivative to the total amount of the urethane-formate derivative and the isocyanurate derivative was 50% by mass.

[0223] Synthesis Example 4 (Preparation of Polyisocyanate D)

[0224] 1,3-Bis(isocyanatomethyl)cyclohexane (1,3-H6XDI) (2000.0 g) and isobutanol (76.4 g) were used. Except for the above, the same operations as in Synthesis Example 1 were carried out to obtain polyisocyanate D. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate groups of 1,3-H6XDI to the hydroxyl groups of isobutanol was 20.

[0225] The isocyanate group content (NCO%) of this polyisocyanate D was 13.5%. In addition, the content ratio of the isocyanurate derivative to the total amount of the urethane-formate derivative and the isocyanurate derivative was 50% by mass.

[0226] Synthesis Example 5 (Preparation of Polyisocyanate E)

[0227] Commercially available VESTANAT T-1890 (isocyanurate derivative of isophorone diisocyanate, manufactured by Evonik Corporation) was prepared. This was used as polyisocyanate E.

[0228] Synthesis Example 6 (Preparation of Polyisocyanate F)

[0229] 2,000.0 g of hexamethylene diisocyanate and 2.9 g of isobutanol were used. Except for the above, the operation was the same as in Synthesis Example 1 to obtain polyisocyanate G. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate group of hexamethylene diisocyanate to the hydroxyl group of isobutanol was 600.

[0230] The isocyanate group content (NCO%) of this polyisocyanate F was 17.1%.

[0231] <Gel Permeation Chromatography (GPC)>

[0232] The molecular weight distribution of each polyisocyanate was measured using the following GPC apparatus.

[0233] Then, the area ratio of the peak corresponding to the urethane-formate derivative to all the peaks was taken as the content rate of the urethane-formate derivative. In addition, the remaining ratio was taken as the content rate of the isocyanurate derivative.

[0234] It should be noted that the peak having a peak top in the molecular weight range of 330 to 430 was the peak corresponding to the urethane-formate derivative.

[0235] GPC apparatus:

[0236] Equipment used: HLC-8020 (manufactured by Tosoh)

[0237] Column used: G1000HXL, G2000HXL and G3000HXL (the above, trade names of Tosoh) were connected in series

[0238] Sample concentration: 0.3% by mass, tetrahydrofuran solution

[0239] Sample injection volume: 100 μL

[0240] Eluent: Tetrahydrofuran

[0241] Flow rate of eluent: 0.8 ml / min

[0242] Column temperature: 40 °C

[0243] Detection method: Differential refractive index

[0244] Standard substance: Polyethylene oxide (manufactured by Tosoh, trade name: TSK standard polyethylene oxide)

[0245] Production Examples 1 to 6

[0246] The first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate were obtained according to the formulations shown in Table 1.

[0247] More specifically, the first polyisocyanate or the second polyisocyanate is mixed with a hydrophilic active hydrogen component, and the reaction is carried out at 80 to 90 °C for 8 hours under dry nitrogen. Then, a neutralizing agent is added, and a solvent is further added to adjust the solid content concentration.

[0248] <Acid value (mgKOH / g)>

[0249] The acid value is measured in accordance with JIS K 1557-5 (2007).

[0250] <Content ratio of sulfonic group (SO3 content, mass%)>

[0251] Regarding SO3 - with a molecular weight of 80, the content ratio of sulfonic group (SO3 content rate) is calculated from the chemical structural formula and the compounding formula.

[0252] <Content ratio of isocyanate group (NCO content, mass%)>

[0253] Using a potentiometric titration device, the content ratio of isocyanate group is measured by the di-n-butylamine method in accordance with JIS K-1556 (2006).

[0254] Examples 1 to 7 and Comparative Examples 1 to 2

[0255] The first water-dispersible polyisocyanate and the second water-dispersible polyisocyanate obtained in each production example are compounded according to the formula shown in Table 2 to obtain a water-dispersible polyisocyanate. It should be noted that in Comparative Example 1, only the first water-dispersible polyisocyanate was used.

[0256] <Evaluation>

[0257] (1) Water dispersibility

[0258] 5 g of the solid content of the water-dispersible polyisocyanate is 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 are evaluated according to the following evaluation criteria.

[0259] ○: No precipitate.

[0260] △: There is a precipitate, but it can be redispersed by stirring.

[0261] ×: There is a precipitate and it cannot be redispersed.

[0262] (2) Pot life

[0263] An aqueous acrylic emulsion with a hydroxyl value of 100 mgKOH / g (solid content concentration of 40.0 mass%) is diluted with water to a solid content concentration of 25 mass%. This aqueous solution is used as the main agent.

[0264] Add each water-dispersed polyisocyanate as a curing agent to the above main agent and stir for 15 minutes. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent to the hydroxyl groups in the main agent is 1.0.

[0265] Then, leave the mixed solution of the main agent and the curing agent standing at 23 °C for 20 hours. Then, evaluate the state of the mixed solution according to the following evaluation criteria.

[0266] ○: No precipitate.

[0267] △: There is a precipitate, but it can be redispersed by stirring.

[0268] ×: There is a precipitate and it cannot be redispersed.

[0269] (3) Curing property

[0270] Dilute an aqueous acrylic emulsion with a hydroxyl value of 50 mg KOH / g (solid content concentration: 40.0% by mass) with water to a solid content concentration of 25% by mass. Use this aqueous solution as the main agent.

[0271] Add each water-dispersed polyisocyanate as a curing agent to the above main agent and stir for 15 minutes. It should be noted that the equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent to the hydroxyl groups in the main agent is 1.0.

[0272] Then, coat the mixed solution of the main agent and the curing agent on a glass plate. It should be noted that the coating amount was adjusted so that the dry thickness became 20 μm. Then, dry the coating film at 70 °C for 30 minutes and cure it at 23 °C for 7 days. Thus, a cured film is obtained.

[0273] Immerse the cured film in a mixed solution of acetone and methanol (mass ratio 1:1) for 24 hours.

[0274] Then, calculate the residual rate of the cured film after immersion and evaluate it according to the following evaluation criteria.

[0275] ○: Residual rate is 90% or more

[0276] ×: Residual rate is less than 90%

[0277] [Table 1]

[0278]

[0279] [Table 2]

[0280]

[0281] Details of the abbreviations in the following tables are described below.

[0282] H6XDI: 1,3-bis(isocyanatomethyl)cyclohexane, TAKENATE 600, manufactured by Mitsui Chemicals, Inc.

[0283] HDI: 1,6-hexamethylene diisocyanate

[0284] PDI: 1,5-pentamethylene diisocyanate

[0285] IPDI: isophorone diisocyanate

[0286] CAPS: 3-(cyclohexylamino)-propanesulfonic acid, a sulfonic acid-containing active hydrogen compound

[0287] DMCHA: N,N-dimethylcyclohexylamine

[0288] PMA: propylene glycol methyl ether acetate

[0289] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but it is merely an example and should not be construed in a limiting sense. Modifications of the present invention apparent to those skilled in the art are included in the appended claims.

[0290] Industrial Applicability

[0291] The water-dispersible polyisocyanate, aqueous polyurethane resin composition, and article of the present invention can be preferably used, for example, in automotive exterior decoration, surface resin coatings of household electric appliances, and flexographic inks for flexible packaging.

Claims

1. A water-dispersible polyisocyanate, which is a water-dispersible polyisocyanate containing an isocyanate group and a sulfo group, The water-dispersible polyisocyanate contains a reaction product of a polyisocyanate component and a hydrophilic active hydrogen component, The polyisocyanate component contains a first polyisocyanate and a second polyisocyanate, The first polyisocyanate contains pentamethylene diisocyanate, The second polyisocyanate contains a polyisocyanate having 6 or more carbon atoms, The hydrophilic active hydrogen component contains a sulfo group-containing active hydrogen compound, The second polyisocyanate is at least one selected from the group consisting of an aliphatic polyisocyanate having 6 or more carbon atoms and an alicyclic polyisocyanate having 6 or more carbon atoms, Relative to the total amount of the first polyisocyanate and the second polyisocyanate, the content ratio of the first polyisocyanate is 40% by mass or more and 90% by mass or less.

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

3. The aqueous-dispersible polyisocyanate according to claim 2, wherein, The isocyanurate derivative of pentamethylene diisocyanate contains a reaction product of a pentamethylene diisocyanate monomer and an alcohol.

4. The aqueous-dispersible polyisocyanate according to claim 3, wherein, The alcohol contains a monohydric alcohol.

5. The aqueous-dispersible polyisocyanate according to claim 1, wherein, The second polyisocyanate contains an isocyanurate derivative of a polyisocyanate having 6 or more carbon atoms, Relative to the total amount of the second polyisocyanate, 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.

6. The aqueous-dispersible polyisocyanate according to claim 1, wherein, Relative to the total amount of the water-dispersible polyisocyanate, the content ratio of the sulfo group is 0.2% by mass or more and 5% by mass or less.

7. The aqueous-dispersible polyisocyanate according to claim 1, wherein, The isocyanate group of the water-dispersible polyisocyanate is blocked with a blocking agent.

8. An aqueous polyurethane resin composition, which comprises: The water-dispersible polyisocyanate according to claim 1; and A compound containing an active hydrogen group.

9. An article, which has an object to be coated and a polyurethane layer disposed on the surface of the object to be coated, The polyurethane layer contains a cured product of the aqueous polyurethane resin composition according to claim 8.

Images