JP6270229B2 - Water-dispersible urethane (meth) acrylate and coating composition - Google Patents

Description

  The present invention provides a water-dispersible urethane (meth) acrylate that is excellent in the balance of physical properties such as oil resistance, hydrolysis resistance, heat resistance, and flexibility, and that provides a coating film having good mechanical strength and wear resistance. And a coating composition.

  Water-dispersed polyurethane resins do not use solvents (or contain only a small amount of solvents) compared to solvent-based urethane resins, so they are environmentally friendly raw materials for paints, flooring materials, wall materials, automobile components, etc. Widely used. Various polyester polyols and polyether polyols are used as the polyol that is a raw material of the water-dispersed polyurethane resin. In the case of a polyurethane emulsion using a polyester polyol, in addition to insufficient hydrolysis resistance of the coating film, there is also a disadvantage that the molecular weight decreases during storage of the emulsion. Moreover, when a polyether polyol is used, the heat resistance is not sufficient and the application is limited.

  In order to improve hydrolysis resistance, heat resistance, wear resistance and the like, a polyurethane emulsion using a polycarbonate diol has been proposed. For example, an organic diisocyanate, an amorphous polycarbonate diol, and a urethane prepolymer composed of a compound having one hydrophilic center and at least two isocyanate-reactive groups, and a reaction product of a chain extender, A polyurethane dispersion that provides a coating film excellent in hydrolyzability, durability, and low-temperature texture has been proposed (see Patent Document 1). In addition, a polyisocyanate component which essentially contains a diisocyanate and optionally contains other polyisocyanate compounds, a polycarbonate diol having an average molecular weight of 500 to 50,000 and a carboxyl group-containing diol, and a polyol component and monoamine compound which optionally contains other polyol compounds Water-dispersible polyurethane composition obtained from an amine component, a carboxyl group neutralizing agent component, and water optionally containing a diamine compound, and an automotive paint using the water-dispersible polyurethane composition are also proposed. (See Patent Document 2). Further, the polyurethane resin is obtained from an isocyanate group-terminated urethane prepolymer using polycarbonate diol as at least one polyol component, and based on the weight of the polyurethane resin, 2.0 to 4.0% by weight of carboxyl groups, 8 A polyurethane resin emulsion containing 0.0 to 14.0% by weight of urethane groups and 1.5 to 9.0% by weight of urea groups has been proposed (see Patent Document 3).

  When the above-mentioned various polyurethane emulsions are used, physical properties such as oil resistance, sweat resistance, hydrolysis resistance, weather resistance, flexibility and adhesion can be imparted in a more balanced manner. However, compared with solvent-based curable urethane, since the crosslink density is low, there is a problem that the strength of the obtained coating film is low and the wear resistance is inferior. For this reason, studies for increasing the crosslinking density in water-based coating compositions have been made in recent years. For example, there has been proposed a water-dispersed slurry paint having sufficient coating strength at the upper layer of the coating film and excellent in scratch resistance and scratch recovery properties at the lower layer of the coating film (see Patent Document 4). Further, it comprises at least a water-soluble and / or water-dispersible polymer having two or more epoxy groups in the molecule, a curing agent, an organic solvent, and water, and the curing agent contains an aliphatic tricarboxylic acid. There has been proposed an aqueous curable composition that can provide a coating film having excellent bending resistance (see Patent Document 5).

  However, there has been no water-based coating composition containing a water-dispersed polyurethane resin that can provide a coating having excellent mechanical strength and abrasion resistance, as well as excellent physical properties such as flexibility.

Japanese Patent No. 3151532 JP 2005-220255 A JP 2006-22221 A JP 2005-206668 A Japanese Patent Laid-Open No. 2005-220241

  The present invention provides a water-dispersible urethane (meth) acrylate that is excellent in the balance of physical properties such as oil resistance, hydrolysis resistance, heat resistance, and flexibility, and that provides a coating film having good mechanical strength and wear resistance. And a water-based curable coating composition using the same.

  As a result of intensive studies to solve the above problems, the present inventor has obtained an organic isocyanate and an isocyanate-reactive group-containing compound having one hydrophilic center, a hydroxyl group-containing (meth) acrylate, and a polycarbonate diol having a specific structure. It was found that the above problems can be solved by forming a coating film using an aqueous curable coating composition containing an aqueous dispersion of a water-dispersible urethane (meth) acrylate obtained by reacting with It came to make.

That is, the present invention has the following configuration.
[1] Reaction of (a) organic isocyanate, (b) polycarbonate diol, (c) compound having one hydrophilic center and at least two isocyanate-reactive groups, and (d) hydroxyl group-containing (meth) acrylate The product is a water-dispersible urethane (meth) acrylate, and the polycarbonate diol (b) is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, the formula (A) 60 to 100 mol% of the repeating unit represented by the formula is a repeating unit represented by the following formula (B) or the following formula (C), and the repeating unit represented by the formula (B) and the formula (C). Said water-dispersible urethane (meth) acrylate characterized by the ratio of the repeating unit represented being 70: 30-30: 70 (molar ratio).



[2] A water-dispersed urethane (meth) acrylate having an average particle size of 30 to 250 nm formed by dispersing the water-dispersible urethane (meth) acrylate according to [1] in water.
[3] A water-based curable coating composition containing the water-dispersed urethane (meth) acrylate according to [2] and a polymerization initiator.

  The water-dispersible urethane (meth) acrylate of the present invention and the water-based curable coating composition using the same are excellent in physical properties such as oil resistance, hydrolysis resistance, heat resistance, flexibility, and good mechanical properties. It has the feature that a coating film having wear resistance can be obtained.

Hereinafter, the present invention will be specifically described.
The water-dispersible urethane (meth) acrylate of the present invention comprises an organic isocyanate (a), a polycarbonate diol (b), a compound (c) having one hydrophilic center and at least two isocyanate-reactive groups, and a hydroxyl group. It is a reaction product of containing (meth) acrylate (d).

Organic isocyanate (a)
Examples of the organic isocyanate (a) used in the present invention include 2,4-triresin diisocyanate, 2,6-triresin diisocyanate and mixtures thereof, diphenylmethane-4,4′-diisocyanate (MDI), and naphthalene-1,5-diisocyanate. (NDI), 3,3′-dimethyl-4,4′-biphenylene diisocyanate (TODI), crude TDI, polymethylene polyphenylene polyisocyanate (PMDI), crude MDI, dianidine diisocyanate, tetramethylxylylene diisocyanate, and other aromatics Diisocyanate, xylylene diisocyanate (XDI), aromatic aliphatic diisocyanate such as p-phenylene diisocyanate, 4,4′-methylenebiscyclohexyl diisocyanate (hydrogenated MDI), isophorone dii Aliphatic diisocyanates such as socyanate (IPDI), cyclohexane diisocyanate (hydrogenated XDI), norbornene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate Examples thereof include, but are not limited to, aliphatic diisocyanates such as lysidine isocyanate.

  From the viewpoint of preventing the light resistance from decreasing, it is preferable to use an alicyclic diisocyanate or an aliphatic diisocyanate, and in addition to this, from the viewpoint of hydrolysis resistance, it is more preferable to use an alicyclic diisocyanate. The organic isocyanate may be used in the form of a modified product such as carbodiimide modification, isocyanurate modification, biuret modification or the like, or may be blocked isocyanate blocked with various blocking agents. Normally, one type of organic isocyanate is selected and used, but two or more types may be selected from these organic isocyanates, and these may be mixed or sequentially added.

  Furthermore, polyisocyanate having three or more isocyanate groups in one molecule can also be used. Examples of the polyisocyanate having 3 or more isocyanate groups in one molecule include triisocyanate triisocyanate, 1-methylbenzol, in addition to the above-mentioned isocyanurate trimer, biuret trimer, trimethylolpropane adduct compound of diisocyanate. -2,4,6-triisocyanate, dimethyltriphenylmethane tetraisocyanate and the like. Further, these may be used in the form of modified products such as isocyanurate modification and biuret modification, or may be used in the form of blocked isocyanate blocked with various blocking agents.

Polycarbonate diol (b)
The polycarbonate diol (b) used in the present invention is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, and is 60 to 100 mol% of the repeating unit represented by the formula (A). Is a repeating unit represented by the following formula (B) or (C), and the ratio of the repeating unit represented by the formula (B) to the repeating unit represented by the formula (C) is 70: 30-30. : 70 (molar ratio). In the polycarbonate diol (b), the ratio of the repeating unit represented by the formula (A) is preferably 95 mol% to 100 mol%, more preferably 98 mol% to 100 mol%, and still more preferably 99 mol%. It is mol% or more and 100 mol% or less.

  In the production of the polycarbonate diol (b) of the present invention, 1,5-pentanediol and 1,6-hexanediol are usually used as diol raw materials. In addition to 1,5-pentanediol and 1,6-hexanediol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,7-heptanediol, 1,8-octanediol, 1,9 -Nonanediol, 1,10-dodecanediol, 1,11-undecanediol, diol having no side chain such as 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2-ethyl-1, 6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5- Has side chains such as pentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol Diol, 1,4-cyclohexanedimethanol, 2-bis (4-hydroxycyclohexyl) - cyclic diols such as propane, one or two or more diols can be used as a raw material. The amount is not particularly limited as long as the ratio of the repeating unit of the polycarbonate diol (b) specified in the present invention is satisfied.

  Further, a compound having 3 or more hydroxyl groups per molecule, for example, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, etc. may be used within the range not impairing the performance of the polycarbonate diol (b) of the present invention. it can. When too many compounds having three or more hydroxyl groups in one molecule are used, gelation occurs due to crosslinking during the polymerization reaction of the polycarbonate. Therefore, when a compound having 3 or more hydroxyl groups in one molecule is used, it is preferably 0.1 to 5% by weight based on the total amount of diols used as a raw material. More preferably, it is 0.1 to 2% by weight.

  The polycarbonate diol (b) of the present invention includes, as carbonates, dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, diaryl carbonates such as diphenyl carbonate, ethylene carbonate, trimethylene carbonate, and 1,2-propylene carbonate. , 1,2-butylene carbonate, 1,3-butylene carbonate, 1,2-pentylene carbonate and other alkylene carbonates. Among these, one or more carbonates can be used as a raw material.

  In the production of the polycarbonate diol (b) of the present invention, a catalyst may or may not be added. When adding a catalyst, it can select freely from a normal transesterification catalyst. For example, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium and other metals, salts, alkoxides, organic compounds Used. Particularly preferred are titanium, tin and lead compounds. Moreover, the usage-amount of a catalyst is 0.00001 to 0.1% of the polycarbonate diol weight normally obtained.

  The method for producing the polycarbonate diol (b) of the present invention is not particularly limited. For example, it can be produced by various methods described in Schnell, Polymer Reviews, Vol. 9, p9-20 (1994).

  Although it does not specifically limit as a manufacturing method of polycarbonate diol (b) used by this invention, Usually, it divides into two steps. As a specific example, using a reactor equipped with a distillation apparatus, in the presence of a transesterification catalyst, a carbonate and a diol are subjected to a reaction temperature of 100 to 170 ° C. and a reduced pressure of 3.0 to 11.0 KPa. The first step of reacting while distilling off the alcohol derived from the carbonate and the carbonate to be azeotropically distilled, and the alcohol and the carbonate are distilled under a reduced pressure of 171 ° C. to 189 ° C. and 0.01 to 3.0 KPa. The manufacturing method etc. which include the 2nd process made to react while leaving are mentioned.

  In the polycarbonate diol (b) used in the present invention, the ratio of the repeating unit represented by the above formula (B) or (C) in the repeating unit represented by the above formula (A) (hereinafter referred to as “principal component ratio”). .) Is 60 to 100 mol%. When the main component ratio is within this range, the coating film obtained from the water-based curable coating composition has a good performance balance such as hydrolysis resistance, heat resistance, and flexibility. If the main component ratio is 60 mol% or more, the viscosity of the polycarbonate diol increases, and the particle size of the water-dispersed urethane (meth) acrylate (water-dispersible urethane (meth) acrylate dispersed in water) increases. In addition, the flexibility of the coating film obtained from the water-based curable coating composition does not decrease. When the ratio of the main component is 75 to 100 mol%, the above problem is less likely to occur. It is most preferable when the main component ratio is 90 to 100 mol%.

  In the polycarbonate diol (b) used in the present invention, the ratio of the repeating unit represented by the above formula (B) and the repeating unit represented by the above formula (C) (hereinafter referred to as “copolymerization ratio”) (B): represented by the above formula (C)) is in a molar ratio of 70:30 to 30:70. When the copolymerization ratio is within this range, the crystallinity of the polycarbonate diol is lowered and the flexibility of the coating film is increased. When the copolymerization ratio is 65:35 to 35:65 in terms of molar ratio, the crystallinity of the polycarbonate diol is further reduced. Furthermore, when the copolymerization ratio is 60:40 to 40:60, the crystallinity of the polycarbonate diol is further reduced, so that a more flexible coating film can be obtained.

  Conventionally, polycarbonate diol is composed of a repeating unit represented by the above formula (C) and a terminal hydroxyl group, and has high crystallinity, but although the resulting coating film has high hydrolysis resistance, heat resistance and chemical resistance, Insufficient flexibility and limited use for coating compositions. In the present invention, the crystallinity is improved with the repeating unit (repeating unit of the above formula (B)) having a methylene chain length close to that of the repeating unit of the above formula (C), having no branched structure, and having an odd number of methylene chains. By reducing, maintaining high hydrolysis resistance, heat resistance and chemical resistance of the coating film obtained, and maintaining good flexibility, it can be used for coating composition applications. It was.

  The range of the average molecular weight of the polycarbonate diol (b) used in the present invention is 500 to 5000 in terms of number average molecular weight. If the number average molecular weight of the polycarbonate diol is 500 or more, the strength of the coating film obtained using the water-dispersible polyurethane (meth) acrylate is not lowered and flexibility is obtained, which is preferable. Further, when the average molecular weight of the polycarbonate diol (b) is 5000 or less, the viscosity of the water-dispersed polyurethane (meth) acrylate is not increased, and the dispersed particle size of the water-dispersed polyurethane (meth) acrylate is suppressed from increasing. And preferred.

Compound (c) having one hydrophilic center and at least two isocyanate-reactive groups
The compound (c) having one hydrophilic center and at least two isocyanate-reactive groups used in the present invention is used for the purpose of maintaining the emulsion stability of the water-dispersed polyurethane (meth) acrylate. The hydrophilic center is, for example, a carboxylic acid group or a sulfonic acid group, and indicates a hydrophilic group that can be neutralized with an alkaline group. The isocyanate-reactive group generally refers to a group that reacts with an isocyanate such as alcohol or amine to form a urethane bond or a urea bond. Specific examples of the compound (c) include compounds represented by the following formula (E) such as 2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid and 2,2-dimethylolvaleric acid. Furthermore, diaminocarboxylic acids such as lysine, cystine, and 3,5-aminocarboxylic acid can be used, but are not limited thereto.

  When the compound (c) having one hydrophilic center and at least two isocyanate-reactive groups is used, it is usually neutralized with a neutralizing agent from the viewpoint of emulsion stability. Examples of neutralizing agents include trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N, N-dimethylethanolamine, N, N-dimethylpropanolamine, N, N-dipropylethanol. Amines, N, N-dialkylalkanolamines such as 1-dimethylamino-2-methyl-propanol, N-alkyl-N, N-dialkanolamines, trialkanolamines such as triethanolamine, sodium hydroxide, potassium hydroxide Lithium hydroxide, ammonia, trimethylammonium hydroxide, and the like. The amount of the neutralizing agent is preferably 0.5 to 2.0 equivalents, more preferably 0.7 to 1.2 equivalents, relative to the number of moles of the hydrophilic center.

Hydroxyl group-containing (meth) acrylate (d)
As the hydroxyl group-containing (meth) acrylate (d) used in the present invention, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, hydroxyhexyl acrylate, 2-hydroxy-3-chloropropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 1,4-butylene glycol monoacrylate, glycerin monoacrylate, propylene glycol monoacrylate, polycaprolactone glycol monoacrylate, trimethylolpropane diacrylate, Pentaerythritol triacrylate, ditrimethylolpropane triacrylate, dipentaerythritol pen Acrylate and methacrylate, and the like to these acrylates can be used as raw materials as long as containing a hydroxyl group (meth) acrylate monomer. These can also be used independently and can also use 2 or more types together.

Water-dispersible urethane (meth) acrylate and its synthesis The water-dispersible urethane (meth) acrylate of the present invention comprises an organic isocyanate (a), a polycarbonate diol (b), one hydrophilic center and at least two isocyanates. It is a reaction product of a compound (c) having a reactive group and a hydroxyl group-containing (meth) acrylate (d). The water-dispersible urethane (meth) acrylate of the present invention can be obtained by a known method. For example, after reacting organic isocyanate (a) with polycarbonate diol (b) to synthesize a prepolymer having an isocyanate group at the end, one hydrophilic center and at least two isocyanate-reactive groups For example, there is a method of reacting a compound (c) having a reaction with a hydroxyl group-containing (meth) acrylate (d).

  In the present invention, the amount of the organic isocyanate (a) is such that the hydroxyl group of the polycarbonate diol (b), the isocyanate reactive group of the compound (c) having one hydrophilic center and at least two isocyanate reactive groups. And 0.9 to 2.0 equivalents, preferably 1.0 to 1.5 equivalents, based on the total equivalent of the hydroxyl group-containing (meth) acrylate (d). If the compounding quantity of organic isocyanate (a) is said range, the structure and molecular weight of water-dispersible urethane (meth) acrylate can be designed freely. The amount of the compound (c) having one hydrophilic center and at least two isocyanate-reactive groups is not particularly limited, but is usually 0.1 to 0.1% relative to the polycarbonate diol (b). 5 molar equivalents, preferably 0.5-2 molar equivalents are used.

  As a specific example of the method for synthesizing the water-dispersible urethane (meth) acrylate of the present invention, an organic isocyanate (a) is added to a reactor equipped with a stirrer in an inert gas atmosphere such as nitrogen, argon or helium. After the temperature is raised to 40 ° C. to 100 ° C., preferably 50 ° C. to 80 ° C., the polycarbonate diol (b) is added for 30 minutes to 10 hours, preferably 1 hour to 3 hours, and the organic isocyanate (a) And a polycarbonate diol (b) are reacted to synthesize a urethane prepolymer. In this reaction, a catalyst may be added in advance if necessary. Next, the compound (c) having one hydrophilic center and at least two isocyanate-reactive groups in a state where the temperature of the reactor is kept at a temperature of 40 ° C. to 100 ° C., preferably 50 ° C. to 80 ° C. Is added in 30 minutes to 3 hours, and then the reaction is performed for 30 minutes to 3 hours in order to complete the reaction. Subsequently, after making the temperature of a reactor into 30 to 80 degreeC, Preferably it is 40 to 60 degreeC, a hydroxyl-containing (meth) acrylate (d) is added in 30 minutes-3 hours. Further, the reaction is performed for 30 minutes to 2 hours to complete the reaction.

  In the process of producing the water-dispersible urethane (meth) acrylate of the present invention, a known catalyst may be used as necessary. Examples of the catalyst include amines such as triethylamine, N-ethylmorpholine, and triethylenediamine, tin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, and tin octylate, and titanium compounds such as tetrabutyltitanate. The amount used is preferably 0.00001 to 0.1% by weight based on the urethane prepolymer produced.

Production method of water-dispersed urethane (meth) acrylate The method of producing the water-dispersed urethane (meth) acrylate by dispersing the water-dispersible urethane (meth) acrylate of the present invention in water is not particularly limited. The method shown in can be mentioned. After synthesizing the water-dispersible urethane (meth) acrylate, neutralization is performed for 30 minutes to 3 hours by adding a neutralizing agent and maintaining the temperature at 40 ° C to 100 ° C, preferably 50 ° C to 80 ° C. Under stirring, water at 15 ° C. to 50 ° C., preferably deionized water or distilled water, is added, and the water-dispersible urethane (meth) acrylate is dispersed in water by stirring.

  Anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants commonly used in emulsions to ensure emulsion stability in the process of dispersing water-dispersible urethane (meth) acrylates in water Agents, polymer surfactants, reactive surfactants, and the like can be used.

  Nonionic surfactants include, for example, aliphatic alcohol alkylene oxide adducts, alkylphenol alkylene oxide adducts, polyhydric alcohol fatty acid esters such as sorbitan monolaurate, fatty acid alkanolamides such as coconut oil fatty acid diethanolamide, (poly Examples thereof include, but are not limited to, dialkylamine oxides such as oxyalkylene alkylphenyl ether, (poly) oxyalkylene alkylamine, and lauryldimethylamine oxide.

  Anionic surfactants include ether carboxylic acids such as sodium lauryl ether acetate or salts thereof, sulfate esters such as sodium lauryl sulfate or salts thereof, (poly) oxyethylene sodium lauryl sulfate, (poly) oxyethylene lauric acid triethanol Examples include, but are not limited to, amines, sulfonates such as sodium dodecylbenzenesulfonate, phosphate esters or salts thereof such as sodium lauryl phosphate, and fatty acid salts such as sodium laurate. Cationic surfactants include, but are not limited to, primary to tertiary amine salts, pyridinium salts, alkylpyridinium salts, and the like.

  The surfactants can be used in any amount as required, but are organic isocyanate (a), polycarbonate diol (b), and one hydrophilic center and at least two isocyanate-reactive. The amount is usually 0.1 to 30% by weight, preferably 3 to 20% by weight, based on the total weight of the urethane prepolymer which is a reaction product of the group-containing compound (c) and the chain extender.

  In the water-dispersible urethane (meth) acrylate used in the present invention, the amount of the organic isocyanate (a) is such that the hydroxyl group of the polycarbonate diol (b), one hydrophilic center and at least two isocyanate-reactive groups. When the amount exceeds 1.0 equivalent with respect to the total equivalent of the isocyanate-reactive group of the compound (c) and the hydroxyl group of the hydroxyl group-containing (meth) acrylate (d), the chain is extended using a chain extender after water dispersion. can do.

  As chain extenders, short chain diols such as water, ethylene glycol, 1,4-butanediol, hydrazine, ethylenediamine, diethyltriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, propylenediamine, hexamethylenediamine, Cyclohexylenediamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylenediamine, α, α'-methylenebis (2-chloroaniline), 3,3'-dichloro-α, α'-biphenylamine, m -Polyamines such as xylenediamine, isophoronediamine, N-methyl-3,3'-diaminopropylamine, and adducts of diethylenetriamine and acrylate or hydrolysis products thereof include, but are not limited to, Not.

  In the step of dispersing the water-dispersible urethane (meth) acrylate of the present invention in water, an organic solvent is added to the water-dispersible urethane (if necessary) in order to reduce the viscosity of the water-dispersible urethane (meth) acrylate to be dispersed in water. It may be added to (meth) acrylate. The organic solvent may be added during the synthesis of the water-dispersible urethane (meth) acrylate, or may be added after the synthesis and before the water dispersion. The organic solvent may be any solvent inert to isocyanate, such as ketones such as methyl ethyl ketone and acetone, esters such as methyl acetate and ethyl acetate, acetonitrile, tetrahydrofuran, toluene, dioxane, and N-methylpyrrolidone. These can be used alone or in admixture of two or more.

  The organic solvent can be removed by heating and vacuuming after the synthesis of the water-dispersible urethane (meth) acrylate, if necessary. Thus, by removing the organic solvent from the coating film almost completely, it is possible to prevent the occurrence of inconveniences such as changes in physical properties of the coating film over time. For that purpose, it is preferable to use an organic solvent having a boiling point of 100 ° C. or lower. When using an organic solvent, it can be used in an amount of 3 to 100% by weight based on the weight of the water-dispersible urethane (meth) acrylate.

  The state of the water-dispersed urethane (meth) acrylate of the present invention is usually an emulsion, suspension, colloidal dispersion or the like. The average particle diameter of the water-dispersed urethane (meth) acrylate (water-dispersible urethane (meth) acrylate in the aqueous dispersion) is preferably 30 to 250 nm. If the average particle diameter of the water-dispersed urethane (meth) acrylate is 30 nm or more, the viscosity of the liquid does not increase, which is preferable. If it is 250 nm or less, the smoothness of the obtained coating film is kept favorable, and the stability and storage stability of the dispersion are not lowered, which is preferable. The average particle diameter of the water-dispersed urethane (meth) acrylate, which is excellent in storage stability and more easily adheres to the particles when forming the coating film to obtain a tough coating film, is preferably 40 to 230 nm, more preferably 50 to 200 nm. It is.

  In the aqueous dispersion containing the water-dispersed urethane (meth) acrylate of the present invention, the amount of the solid content is not particularly limited, but is usually 10 to 70% by weight, preferably 20 to 60% by weight. .

Preparation of water-based curable coating composition The water-based curable coating composition of the present invention contains the above water-dispersed urethane (meth) acrylate and a polymerization initiator, and, if necessary, other water-dispersible resins, cross-linking agents, Prepared with the addition of additives.

  Since the water-dispersed urethane (meth) acrylate of the present invention has a double bond of (meth) acryloyl group, it can be cured by heating if a thermal polymerization initiator is added, and a photopolymerization initiator can be added. For example, it can be easily cured in a short time by ultraviolet irradiation using an ultraviolet fluorescent lamp or a high-pressure mercury lamp, or irradiation with an electron beam. The concentration of these polymerization initiators is 0.1 to 20% by weight, preferably 1 to 10% by weight, more preferably 2 to 5% by weight, based on the water-dispersed urethane (meth) acrylate. If the polymerization initiator is 0.1% by weight or more, it is possible to achieve sufficient curing, and if it is 20% by weight or less, it is possible to suppress deterioration of the properties of the resulting cured product, preferable.

  Examples of the thermal polymerization initiator include peroxides such as benzoyl peroxide, lauroyl peroxide, bis- (4-t-butylcyclohexyl) peroxydicarbonate, and 2,2′-azobis-isobutyronitrile, Examples include azo compounds such as 2,2′-azobis-2,4-dimethylvaleronitrile. These thermal polymerization initiators can be used alone or in combination of two or more. The heating temperature varies depending on the adhesion and the substrate to be applied, but is usually from room temperature to 90 ° C, preferably from 40 ° C to 80 ° C.

  Examples of the photopolymerization initiator include benzophenone, ω-bromoacetophenone, chloroacetone, acetophenone, diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p, p'-dichlorobenzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, Michler's ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n -Butyl ether, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methylbenzoy Formate, 2,2-diethoxyacetophenone, 4-N, carbonyl-based photopolymerization initiators such as N'- dimethyl acetophenone. Furthermore, sulfide photopolymerization initiators such as diphenyl disulfide, dibenzyl disulfide and tetraethylmethylammonium sulfide, quinone photopolymerization initiators such as benzoquinone, t-butylanthraquinone and 2-ethylanthraquinone, 2,2′-azobispropane , Azo photopolymerization initiators such as hydrazine, thioxanthone photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, peroxide photopolymerization initiators such as benzoyl peroxide and di-t-butyl peroxide Agents and the like. These photopolymerization initiators can be used alone or in combination of two or more.

  Further, if necessary, a photopolymerization initiator and a known photosensitizer can be used in combination. Examples of the photosensitizer include 4-dimethylaminobenzoic acid, ethyl 4-dimethylaminobenzoate, amyl 4-dimethylaminobenzoate, 4-dimethylaminoacetophenone and the like. I can decide.

  For the purpose of improving storage stability, antioxidants and light stabilizers such as hindered amines, hindered phenols, and benzotriazoles can be used. Examples of these include ADK STAB AO-20, ADK STAB AO-30, ADK STAB AO-40, ADK STAB AO-50, ADK STAB AO-60, ADK STAB AO-70, ADK STAB AO-80, ADK STAB AO-330, ADK STAB PEP-4C ADK STAB PEP-8, ADK STAB PEP-24G, ADK STAB PEP-36, ADK STAB HP-10, ADK STAB 2112, ADK STAB 260, ADK STAB 522A, ADK STAB 329A, ADK STAB 1500, ADK STAB C, ADK STAB 135A, ADK STAB Made by Co., Ltd.), Sumizer BHT, Summarizer S, Summarizer BP-76, Summarizer MDP-S, Summarizer GM, Summarizer BBM-S, Millizer WX-R, Summarizer NW, Summarizer BP-101, Summarizer GA-80, Summarizer TNP, Summarizer BP-179, Sumilizer TPP-R, Summarizer P-16 (above, manufactured by Sumitomo Chemical Co., Ltd.), Tinuvin 770, Tinuvin 765 Tinuvin 144, Tinuvin 622, Tinuvin 111, Tinuvin 123, Tinuvin 292 (manufactured by BASF Japan Ltd.) and the like. Although the addition amount of these antioxidants and light stabilizers is not particularly limited, when used, it is usually used in an amount of 0.001 to 5% by weight based on the aqueous curable coating composition containing water-dispersed urethane (meth) acrylate. It is done.

  Examples of other water-dispersible resins or aqueous resin compositions include water-dispersed or water-soluble polyurethane resins other than the water-dispersible urethane (meth) acrylate of the present invention, acrylic, styrene / acrylic copolymers, saran, Examples thereof include synthetic resin emulsions such as vinyl acetate, vinyl acetate / acrylic copolymer, and ethylene / vinyl acetate copolymer. The content of these resins in the water-based curable coating composition is usually 60% by weight or less, preferably 50% by weight or less of the composition.

  Other additives generally include pigments, dyes, pigment dispersants, light stabilizers, auxiliary binders, thickeners, leveling agents, thixotropy imparting agents, antifoaming agents, foaming agents, ultraviolet absorbers, and antioxidants. , Thickener, film-forming aid, curing agent, silane coupling agent, anti-blocking agent, anti-gelling agent, dispersion stabilizer, radical scavenger, inorganic or organic filler, plasticizer, lubricant, antistatic agent , Antibacterial agents, fungicides, antiseptics, antifreeze agents, and the like, but are not limited thereto.

  Moreover, a solvent can also be added in order to improve the coating film appearance after drying. Examples of the solvent include C1-C20 monohydric alcohols such as methanol, ethanol, and propanol, glycols such as ethylene glycol, propylene glycol, and diethylene glycol, trihydric alcohols such as glycerin, and cellosolves such as methyl cellosolve and ethyl cellosolve. Can be used. The addition amount is preferably 20% by weight or less, more preferably 15% by weight or less, based on the weight of the water-based curable coating composition.

  In addition, various substances such as natural or synthetic polymer substances, fillers, modifiers, extenders and the like may be added to the water-based curable coating composition as necessary. These compounding amounts can be appropriately determined according to the application within a range not impairing the performance of the present invention.

  The water-based curable coating composition of the present invention is produced by mixing and stirring the above water-dispersed urethane (meth) acrylate and each of the above optional components. In mixing, all the components may be mixed at the same time, or each component may be added in stages and mixed. The solid content concentration of the water-based curable coating composition of the present invention is usually 10 to 70% by weight, preferably 15 to 60% by weight.

  The water-based curable coating composition of the present invention can be used for, for example, wood, plastic, metal, glass, foam and molded articles thereof. Specific examples of coating objects (base materials) include wooden furniture products such as tables, chairs, cupboards, and storage racks, automotive interior parts such as instrument panels, center consoles, and door trims, and light electrical appliances such as computers, televisions, and washing machines. Products, wall materials, flooring materials (wood flooring, PVC sheets, panels, etc.), and building interior materials such as ceiling materials. In particular, when the water-based curable coating composition of the present application is used for a wood material, it can be suitably used because it is easy to dry as a result of the wood absorbing moisture. A base material can be coated with the water-based curable coating composition of the present invention and dried to form a coating film. In addition, a primer can be applied to the substrate before using the paint of the present invention.

  The method for applying the water-based curable coating composition of the present invention to a substrate is not particularly limited. For example, spray coating, roll coater method, bell coating, disc coating, brush coating and the like can be mentioned. The coating amount can be freely set depending on the purpose of coating and the type of the substrate, but is usually applied so that the coating thickness at the time of drying is 15 to 50 μm. Drying may be performed at room temperature or may be heated. When heating, it is normally performed at 60 to 150 ° C. for 3 to 60 minutes.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited by these examples at all.
The physical property values shown in the following examples and comparative examples were measured by the following methods.

1) Number average molecular weight of polycarbonate diol The hydroxyl value was determined according to JIS K1557-1 and calculated using the following mathematical formula (1).
Number average molecular weight = 2 / (OH value × 10 ⁻³ /56.1) (1)

2) Copolymerization ratio of polycarbonate diol 1 g of a sample was taken into a 100 ml eggplant flask, 30 g of ethanol and 4 g of potassium hydroxide were added, and reacted at 100 ° C. for 1 hour. After cooling the reaction solution to room temperature, 2-3 drops of phenolphthalein was added to the indicator and neutralized with hydrochloric acid. After cooling in the refrigerator for 1 hour, the precipitated salt was removed by filtration and analyzed using GC (gas chromatography). GC analysis was performed using gas chromatography GC-14B (manufactured by Shimadzu Corporation, Japan) with DB-WAX (manufactured by J & W, USA) as a column, diethylene glycol diethyl ester as an internal standard, and a detector as FID. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min.

  Using the above analysis results, from the molar ratio of 1,5-pentanediol and 1,6-hexanediol, the copolymerization ratio (number of moles of 1,5-pentanediol when the whole is 100: 1,6 -The number of moles of hexanediol).

3) Average particle diameter of water-dispersed urethane (meth) acrylate The average particle diameter (nm) of water-dispersed urethane (meth) acrylate was measured using a particle size analyzer Nanotrac150 (manufactured by Microtrac).

4) Tensile breaking strength and breaking elongation A predetermined amount of an aqueous curable coating composition formed by adding a photopolymerization initiator to an aqueous dispersion containing water-dispersed urethane (meth) acrylate is poured onto an aluminum dish, After standing at room temperature for 24 hours, heat treatment was performed at 60 ° C. for 24 hours to prepare a sheet having a thickness of 500 μm. Further, this sheet was irradiated with 3000 mJ / cm ² of ultraviolet rays to obtain an ultraviolet curable sheet. (Using a UV irradiator manufactured by IL390C Light Bug, International Light Inc.)
A sample of a polyurethane resin film having a width of 6.6 mm and a length of 60 mm was cut out from this sheet. Using a Universal Testing Machine (manufactured by Zwick Corp.) in a temperature-controlled room, the tensile breaking strength (MPa) and elongation at break (%) of the sample film were measured at a chucking distance of 20 mm and a tensile speed of 5 mm / min. . This sample film was also used for evaluating flexibility and oil resistance.

5) Flexibility The test was performed by the method shown in 4) above, and the stress (MPa) at the time of 50% elongation (at the time of 25 mm elongation) was measured. The lower the stress, the higher the flexibility.

6) Oil resistance The oil resistance (swelling rate) after the sample film was immersed in oleic acid at 45 ° C for 1 week was measured. The oil resistance (swelling rate) was determined using the following mathematical formula (2).
Oil resistance (%) = {(weight after test−weight before test) / weight before test} × 100 (2)

7) Weather resistance In the sunshine type weatherometer WEL-SUN-DC (manufactured by Suga Test Instruments Co., Ltd.), after a predetermined time (200 hours) has elapsed with a cycle of 60 minutes (of which 12 minutes of precipitation), the above 4) Tensile breaking strength (MPa) was measured by the indicated method. The retention (%) of the value after the test compared with the value before the test was regarded as weather resistance.

8) Film surface hardness Using an aqueous curable coating composition formed by adding a photopolymerization initiator to an aqueous dispersion containing water-dispersed urethane (meth) acrylate, and using an applicator on a polycarbonate plate having a thickness of about 2 mm. After curing, coating was performed so that the film thickness was about 50 μm, and UV photopolymerization was performed at an illuminance of 800 mJ / W using a UV irradiator (Oak Manufacturing Co., Ltd., Handy UV-300) to obtain a cured coating film. The resulting cured coating film was measured and evaluated for pencil hardness according to JIS K-5400.

9) Appearance of cured coating film The surface of the coating film cured by the same operation as in 8) above was visually observed. X (defect) is marked with fine irregularities such as orange peel, △ (slightly poor) is slightly observed with fine irregularities such as orange peel, and ○ (good) is not recognized It was judged.

10) Abrasion resistance The cured coating film obtained by the same operation as in 8) above was evaluated according to the JIS K5600 wear wheel method (wear wheel CS-10, weight 500 g, 500 rotations). The weight loss measurement result (mg) in the test is shown.

[Polycarbonate diol polymerization example 1]
In a 2 L glass flask equipped with a rectification column packed with a regular packing and a stirrer, 449 g (5.1 mol) of ethylene carbonate, 260 g (2.5 mol) of 1,5-pentanediol, 1,6- 310 g (2.6 mol) of hexanediol was charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 7 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C., the pressure was 10 to 15 kPa, and the reaction was performed for 3 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 3 hours, reducing pressure gradually to 0.5kPa. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC1.

[Polycarbonate diol polymerization example 2]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 310 g (2.6 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, and the mixture was stirred and heated at normal pressure. The reaction temperature was 150 ° C. to 190 ° C., the pressure was 3.0 to 5.0 kPa, and the reaction was carried out for 10 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Thereafter, the pressure was reduced to 0.5 kPa, and the mixture was further reacted at 190 ° C. for 5 hours while distilling off ethylene carbonate and diol. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC2.

[Polycarbonate diol polymerization example 3]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 310 g (2.6 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethylene glycol and ethylene carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was carried out for 5 hours while distilling off the mixture of ethylene glycol and dimethyl carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC3.

[Polymerized diol polymerization example 4]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 166 g (1.6 mol) of 1,5-pentanediol, and 418 g (3.5 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 5 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC4.

[Polymerized diol polymerization example 5]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 364 g (3.5 mol) of 1,5-pentanediol, and 189 g (1.6 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 5 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC5.

[Polymerized diol polymerization example 6]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 225 g (2.5 mol) of 1,4-butanediol, and 307 g (2.6 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 5 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1 (the main component ratio is 55 mol%). This polycarbonate diol is referred to as PC6.

[Polymerized diol polymerization example 7]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate and 602 g (5.1 mol) of 1,6-hexanediol were charged. Titanium tetrabutoxide (0.10 g) was added as a catalyst, and the reaction was conducted under the same conditions as in Polymerization Example 1. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC7.

[Polymerized diol polymerization example 8]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 251 g (3.3 mol) of 1,3-propanediol, 146 g (1.4 mol) of 1,5-pentanediol, 165 g (1.4 mol) of 6-hexanediol was charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 5 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1 (the main component ratio is 54 mol%). This polycarbonate diol is referred to as PC8.

[Polymerized diol polymerization example 9]
Using the same apparatus as in Polymerization Example 1, 449 g (5.1 mol) of ethylene carbonate, 406 g (3.9 mol) of 1,5-pentanediol, and 142 g (1.2 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 5 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The result of analyzing the obtained polycarbonate diol is shown in Table 1 (the main component ratio is 100 mol%). This polycarbonate diol is referred to as PC9.

Synthesis example 1 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
98.6 g (0.444 mol) of isophorone diisocyanate was placed in a 1000 ml four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet pipe, and a thermometer. Nitrogen was introduced into the flask at a rate of 0.1 cc / min, heated to 70 ° C. using an oil bath while stirring, 0.05 g of dibutyltin dilaurate was added as a catalyst, and 150 g (0.185) was added using a dropping funnel. Mol) of polycarbonate diol PC1 was added dropwise over 2 hours, and the mixture was further reacted by stirring for 1 hour. Next, 12.5 g (0.093 mol) of dimethylolpropionic acid (manufactured by Cross Organics, hereinafter referred to as DMPA) was added dropwise over 1.5 hours, and the reaction was further continued for 1 hour. After the temperature in the reaction vessel is adjusted to 50 ° C., 24.1 g (0.185 mol) of 2-hydroxyethyl methacrylate (manufactured by Junsei Chemicals) is dropped over 2 hours using a dropping funnel, and further stirred for 3 hours. To obtain water-dispersible urethane (meth) acrylate. 9.4 g (0.093 mol) of triethylamine was added and stirred for 30 minutes at a stirring speed of 100 rpm. After the temperature in the reactor is 40 ° C., the stirring speed is 250 rpm, 425 g of deionized water at 40 ° C. is added dropwise over 1 hour, and the reaction is continued with stirring for 1 hour to obtain water-dispersed urethane (meth) acrylate. Obtained. This water-dispersed urethane (meth) acrylate is referred to as PUD1.

Synthesis example 2 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
PC2 was used instead of PC1, the amount of PC2 was changed to 192 g (0.185 mol), and the amount of deionized water added was changed to 480 g. Obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD2.

Synthesis example 3 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
In the same manner as in Synthesis Example 1, except that a 2000 ml four-necked flask was used, PC3 was used instead of PC1, the amount of PC3 was 366 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD3.

Synthesis example 4 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
In the same manner as in Synthesis Example 1, except that a 2000 ml 4-neck flask was used, PC4 was used instead of PC1, the amount of PC4 was 364 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD4.

Synthesis example 5 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
In the same manner as in Synthesis Example 1, except that a 2000 ml 4-neck flask was used, PC5 was used instead of PC1, the amount of PC5 was 372 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD5.

Synthesis example 6 of water-dispersible urethane acrylate and water-dispersed urethane acrylate
In place of 2-hydroxyethyl methacrylate, 21.5 g (0.185 mol) of 2-hydroxyethyl acrylate was used, and water dispersion was performed in the same manner as in Synthesis Example 1 except that the amount of deionized water added was 421 g. Urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD6.

Synthesis example 7 of water-dispersible urethane acrylate and water-dispersed urethane acrylate
Water-dispersed urethane was prepared in the same manner as in Synthesis Example 1 except that 55.1 g (0.185 mol) of pentaerythritol triacrylate was used instead of 2-hydroxyethyl methacrylate, and the amount of deionized water added was 471 g. A (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD7.

Synthesis example 8 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate
98.6 g (0.444 mol) of isophorone diisocyanate was placed in a 2000 ml four-necked flask equipped with a stirrer, a condenser, a nitrogen inlet pipe, and a thermometer. Nitrogen was introduced into the flask at a rate of 0.1 cc / min, heated to 70 ° C. using an oil bath while stirring, 0.05 g of dibutyltin dilaurate was added as a catalyst, and 367 g (0.185) using a dropping funnel. Mol) of polycarbonate diol PC3 was added dropwise over 2 hours, and the mixture was further stirred for 1 hour to be reacted. Next, 12.5 g (0.093 mol) of dimethylolpropionic acid (manufactured by Cross Organics, hereinafter referred to as DMPA) was added dropwise over 1.5 hours, and the reaction was further continued for 1 hour. After the temperature in the reaction vessel is adjusted to 50 ° C., 24.1 g (0.185 mol) of 2-hydroxyethyl methacrylate (manufactured by Junsei Chemicals) is dropped over 2 hours using a dropping funnel, and further stirred for 3 hours. To obtain water-dispersible urethane (meth) acrylate. 9.4 g (0.093 mol) of triethylamine was added and stirred for 30 minutes at a stirring speed of 100 rpm. After the temperature in the reactor is 40 ° C., the stirring speed is 150 rpm, 425 g of deionized water at 40 ° C. is added dropwise over 1 hour, and the reaction is continued with stirring for 1 hour to obtain water-dispersed urethane (meth) acrylate. Obtained. This water-dispersed urethane (meth) acrylate is referred to as PUD8.

Synthesis Comparative Example 1 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate 1
In the same manner as in Synthesis Example 1, except that a 2000 ml four-necked flask was used, PC6 was used instead of PC1, the amount of PC6 was 363 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD9.

Synthesis Comparative Example 2 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate 2
In the same manner as in Synthesis Example 1, except that a 2000 ml four-necked flask was used, PC7 was used instead of PC1, the amount of PC7 was 368 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD10.

Synthesis Comparative Example 3 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate 3
In the same manner as in Synthesis Example 1, except that a 2000 ml four-necked flask was used, PC8 was used instead of PC1, the amount of PC8 was 374 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD11.

Synthesis Comparative Example 4 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate 4
In the same manner as in Synthesis Example 1, except that a 2000 ml 4-neck flask was used, PC9 was used instead of PC1, the amount of PC9 was 364 g (0.185 mol), and the amount of deionized water added was 758 g. Water-dispersed urethane (meth) acrylate was obtained. The water-dispersed urethane (meth) acrylate is referred to as PUD12.

Synthesis Comparative Example 5 of water-dispersible urethane (meth) acrylate and water-dispersed urethane (meth) acrylate 5
Using a 2000 ml 4-neck flask, instead of PC1, polyester polyol (made by DIC Corporation, polyester polyol composed of adipic acid and 1,4-butanediol, molecular weight 2000) was used, and the amount of polyester polyol was 370 g (0.185). And water-dispersed urethane (meth) acrylate was obtained in the same manner as in Synthesis Example 1 except that the amount of deionized water added was 758 g. The water-dispersed urethane (meth) acrylate is referred to as PUD13.

Comparative Example of Synthesis of Water-Dispersed Polyurethane 98.6 g (0.444 mol) of isophorone diisocyanate was placed in a 1000 ml four-necked flask equipped with a stirrer, a cooling tube, a nitrogen inflow tube, and a thermometer. Nitrogen was introduced into the flask in an amount of 0.1 cc / min, heated to 70 ° C. using an oil bath while stirring, 0.05 g of dibutyltin dilaurate was added as a catalyst, and 148 g (0.185) using a dropping funnel. Mol) of polycarbonate diol PC1 was added dropwise over 2 hours, and the mixture was further reacted by stirring for 1 hour. Next, 12.5 g (0.093 mol) of dimethylolpropionic acid (manufactured by Cross Organics, hereinafter referred to as DMPA) was added dropwise over 1.5 hours, and the reaction was further continued for 1 hour. After the temperature in the reaction vessel was adjusted to 50 ° C., 9.4 g (0.093 mol) of triethylamine was added and stirred for 30 minutes. After the temperature in the reactor was 40 ° C., 425 g of 40 ° C. deionized water was added dropwise over 1 hour, and the mixture was further stirred for 1 hour to obtain a water-dispersed urethane prepolymer. 6 g (0.1 mol) of ethylenediamine was added as a chain extender and stirred for 1 hour to obtain a water-dispersed polyurethane. This water-dispersed polyurethane is referred to as PUD14.

[Examples 1-8, Comparative Examples 1-6]
3% by weight of PUD 1-14 with Ciba Specialty Chemicals, Irgacure 500 (a mixture of 50% by weight of 1-hydroxy-cyclohexyl-phenyl ketone and 50% by weight of benzophenone) as a photopolymerization initiator based on the solid content of each PUD After addition, a sample film was formed by the method shown in 4) above, and the tensile strength at break, elongation at break, flexibility, oil resistance and weather resistance were evaluated. The results are shown in Table 2.

  The examples of the present invention all have high tensile strength at break and elongation at break, and are found to have an excellent balance of flexibility, oil resistance, and weather resistance.

[Examples 9 to 16, Comparative Examples 7 to 12]
3% by weight of PUD 1-14 with Ciba Specialty Chemicals, Irgacure 500 (a mixture of 50% by weight of 1-hydroxy-cyclohexyl-phenyl ketone and 50% by weight of benzophenone) as a photopolymerization initiator based on the solid content of each PUD After addition, a coating film was formed by the method shown in 8) above, and the surface hardness, coating film appearance, and abrasion resistance were evaluated. The results are shown in Table 3.

  All of the examples of the present invention were found to have a good balance of properties in terms of surface hardness, appearance and wear resistance.

  The water-dispersible urethane (meth) acrylate according to the present invention has excellent balance of physical properties such as good tensile strength at break, elongation at break, flexibility, oil resistance, and weather resistance, and also has good surface hardness, appearance, and wear resistance. Since the coating film which has this is obtained, it can utilize suitably for the use of a water-system curable coating composition. The water-based curable coating composition of the present invention can be used for, for example, wood, plastic, metal, glass, foam and molded articles thereof, and can be suitably used particularly for woody materials.

Claims (3)

(A) an organic isocyanate, (b) a polycarbonate diol, (c) a compound having a hydrophilic group capable of neutralization with one alkaline group and at least two isocyanate-reactive groups, and (d) a hydroxyl group-containing (meta ) A water-dispersible urethane (meth) acrylate which is a reaction product of acrylate (except for a water-dispersible urethane (meth) acrylate comprising 25 to 80% by mass of a hydroxyl group-containing (meth) acrylate (d)). The polycarbonate diol (b) is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, and 60 to 100 mol% of the repeating unit represented by the formula (A) is: The repeating unit represented by the following formula (B) or the following formula (C), the repeating unit represented by the formula (B) and the formula (C) The proportion of the repeating unit represented is 70: 30-30: 70 (molar ratio), number average molecular weight of the polycarbonate diol (b) is 500 or more, characterized in that 5,000 or less, the above aqueous dispersion Urethane (meth) acrylate.


  A water-dispersed urethane (meth) acrylate having an average particle size of 30 to 250 nm formed by dispersing the water-dispersible urethane (meth) acrylate according to claim 1 in water. An aqueous curable coating composition comprising the water-dispersed urethane (meth) acrylate according to claim 2 and a polymerization initiator.