JP5053718B2 - Solvent-free aqueous polyurethane resin composition and method for producing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a solventless aqueous polyurethane resin composition, and in particular, a polyol component containing a specific hydroxyl group-containing compound obtained by reacting an unsaturated carboxylic acid with an epoxy compound and an aromatic isocyanate component as essential components, and having a terminal fatty acid. TECHNICAL FIELD The present invention relates to a solvent-free water-based polyurethane resin composition for paints obtained by dispersing a urethane prepolymer, which is an aliphatic or alicyclic isocyanate, in water, and a method for producing the solvent-free water-based polyurethane resin.

  Polyurethane resin is used in paints or adhesives for metal products, woodwork products, plastic products, concrete products, etc., as well as processing agents such as paper, fiber, woven fabric, non-woven fabric, glass fiber bundling agent, mortar modifier, etc. Has been widely used. In these applications, conventionally used as a solvent-based varnish in which polyurethane resin is dissolved in an organic solvent, this solvent-based varnish has drawbacks such as toxicity due to organic solvent, fire hazard, and environmental pollution. Therefore, in recent years, an aqueous resin using water instead of the organic solvent has been used.

  Problems with the above water-based resin for paints (especially for woodworking) include water resistance, solvent resistance (alcohol) resistance and alkali resistance of coating films (hereinafter sometimes referred to simply as barrier properties), and room temperature drying characteristics. There is. That is, in the conventional solvent-based resin paint using an organic solvent, since it is easy to reduce the viscosity of the resin with a solvent, it was possible to introduce a large amount of a crosslinking agent even in a one-component curing system. Since it is difficult to reduce the viscosity in the case of water-based resin paints, the amount of the crosslinking agent used in the one-component curing system must be limited, and as a result, the crosslinking density of the urethane resin cannot be increased. It had the fault that the barrier property of a coating film was inferior. In order to disperse in water, the water-based urethane resin is synthesized by a method such as self-emulsification by incorporating a compound having a hydrophilic group into the urethane resin structure, or forced emulsification with an emulsifier. The water resistance is inevitably inferior because it is dispersed in water with good familiarity.

  In contrast, in the case of a two-component curing system, as a means of improving water resistance, a barrier structure is formed by forming a crosslinked structure with a crosslinking agent capable of reacting with an ionic hydrophilic group, which is one of the causes of poor water resistance. To improve the performance. However, in this case, in order to obtain satisfactory barrier properties, the number of cross-linking points must be increased, and the hydrophilic group component is generally a low-molecular polyol. Therefore, increasing the hydrophilic group is the main structure of the urethane structure. Since the urethane bond concentration is increased, the flexibility characteristic of the urethane resin is remarkably impaired, and the viscosity of the prepolymer is increased to deteriorate the workability.

In addition, as a means for increasing the crosslinking density of the urethane structure, it is well known to use a trifunctional or higher polyfunctional polyol or a polyfunctional isocyanate compound. In this case, too, a satisfactory barrier property can be obtained. When the crosslinking density is increased, it is extremely difficult to produce an aqueous resin system because the viscosity of the urethane prepolymer becomes too high. As means for improving such problems, it has been proposed to use a hydrazino group as a cross-linking agent (Patent Document 1 and the like). Couldn't get.
JP 07-113061 A

  Furthermore, it is also known to use aromatic isocyanate as a means for improving the barrier property, but urethane prepolymers using this are easily reactive with water due to the high reaction activity of isocyanate groups, so that carbon dioxide is produced. Therefore, there are problems in production such as foaming when dispersed in water, and physical properties of the coating film are deteriorated due to an increase in urea bonds caused by reaction with water.

On the other hand, with regard to the problem of drying, this defect can be tolerated to some extent in applications where a drying process by heating is possible, but it is a major problem especially in applications such as woodwork paints that require drying at room temperature. There is a high demand for improvement of sex. As means for solving this problem, a method of lowering the minimum film-forming temperature (M.F.T) using an organic solvent as a film-forming auxiliary has been proposed (Patent Document 2 and Patent Document 3). Since the organic solvent remains in the coating film, the drying property is insufficient, and problems remain in environmental problems such as VOC regulations. In addition, a method using a hydrophobic polyol has also been proposed (Patent Document 4), but in this case as well, a satisfactory product in terms of drying properties could not be obtained.
JP 2000-068276 A JP 2000-108262 A JP 2005-154721 A

  Under such circumstances, high boiling point N-methyl-2-pyrrolidone (hereinafter referred to as NMP) is currently used as a urethane resin solvent for many water-based polyurethane resins because of its excellent solubility in urethane resins and water. However, since this substance has a high boiling point, it is difficult to remove the solvent from the aqueous resin, and it is forced to remain. However, since this residual NMP remains in the coating film even after the drying step, it causes various problems in terms of drying properties, barrier properties, VOC, and the like.

Furthermore, as a room temperature curing technique, a technique in which oxidative polymerization is applied to a water-based urethane resin is also known (Patent Document 5 and others). In this case, however, alkali resistance, water resistance, paint repellency, and surface adhesiveness remain. There were problems such as. As a technique for solving these problems, it has been proposed to combine a fatty acid-modified monomer of an unsaturated fatty acid such as a drying oil and a specific epoxy compound (Patent Document 6), but it has come to sufficiently solve the above problems. Not in.
As described above, there is still a demand for further development of a solventless aqueous urethane resin that does not contain an organic solvent.
JP 58-501036 A JP 2006-036990 A

Accordingly, the first object of the present invention is not only excellent in barrier properties (water resistance, solvent resistance (alcohol) resistance and alkali resistance) of a coating film suitable for coating materials, but is also a solvent-free solvent excellent in room temperature drying properties. A water-based polyurethane resin composition is provided.
The second object of the present invention is to provide a method for producing a solventless aqueous polyurethane resin composition excellent in barrier properties and room temperature drying properties of a coating film suitable for coatings.

As a result of intensive studies to solve the above-mentioned objects, the present inventors have determined that a polyol component containing a hydroxyl group-containing compound obtained by reacting a specific unsaturated carboxylic acid with an epoxy compound and an aromatic isocyanate in a methyl ethyl ketone solvent. By reacting to obtain a urethane prepolymer having a terminal hydroxyl group, the terminal hydroxyl group is further reacted with an aliphatic or alicyclic isocyanate to convert the terminal to an aliphatic or alicyclic isocyanate, and acetone is added to the resulting water. It was found that a water-based polyurethane resin excellent in barrier properties and room temperature drying properties can be obtained when dispersed, polymerized and desolventized, and the present invention has been achieved.

That is, in the present invention, a polyol prepolymer (A) and an isocyanate component (B) are reacted in a methyl ethyl ketone solvent to prepare a urethane prepolymer having a terminal aliphatic or cycloaliphatic isocyanate, which is diluted with an acetone solvent. A solvent-free aqueous polyurethane resin composition which is dispersed in post-water and then desolvated, wherein the polyol component (A) is an epoxy compound (a1) having 1 to 3 epoxy groups in one molecule. , linseed oil, safflower oil, poppy oil, tung oil, walnut oil, soybean oil and rapeseed Abura及 beauty hydroxyl group-containing compound obtained by reacting at least one unsaturated carboxylic acid selected from these modified oils (a2) (A1) A polyol (A2) having 2 or 3 hydroxyl groups and a number average molecular weight of less than 500, a polyol having 2 to 3 hydroxyl groups and a number average molecular weight of 500 to 5000 (A3) and a polyol component having an anionic group-containing polyol (A4) as an essential component, and the isocyanate component (B) is an aromatic isocyanate (B1) and an aliphatic and / or alicyclic isocyanate (B2). And the ratio of each component in the polyol component (A) is (A1) 5.0 to 65.0 mass%, (A2) 0.5 to 35.0 mass%, It is a solvent-free aqueous polyurethane resin composition and a method for producing the same, which are in the range of (A3) 10.0 to 80.0% by mass and (A4) 1.0 to 25.0% by mass. .

  In the present invention, the aromatic isocyanate (B1) is preferably tolylene diisocyanate, and the aliphatic and / or alicyclic isocyanate (B2) is isophorone diisocyanate, hexamethylene diisocyanate and 4-4. It is preferably at least one selected from the group of '-dicyclohexylmethane diisocyanate. The epoxy compound (a1) having 1 to 3 epoxy groups in one molecule is preferably diglycidyl ether of bisphenol A and / or bisphenol F, and the anionic group-containing polyol (A4) Is preferably dimethylolpropionic acid and / or dimethylolbutanoic acid. Furthermore, the water-based polyurethane resin composition of the present invention can be further polymerized using a chain extender component (C).

The solvent-free aqueous polyurethane resin composition of the present invention is not only useful as a modifier for other aqueous resin emulsions, but also has barrier properties when used as a coating (solvent resistance such as water resistance and alcohol resistance). In addition, it is particularly suitable as a coating material and can be used as a one-pack type. Moreover, since the manufacturing method of the solvent-free water-based polyurethane resin composition of the present invention comprises only ordinary steps, it is excellent in manufacturing suitability.
Hereinafter, the solventless aqueous polyurethane resin composition of the present invention and the production method thereof will be described in detail.

  The epoxy compound (a1) having 1 to 3 epoxy groups in one molecule used in the present invention can be appropriately selected from known compounds used for epoxy resins. In the present invention, in particular, the bifunctional hydroxyl group-containing compound (A1) having two hydroxyl groups can be incorporated into the urethane main chain by causing chain elongation reaction without causing extreme thickening during the synthesis of the urethane prepolymer. From the viewpoint of being preferable because it becomes possible, it is preferable to use a bifunctional epoxy compound from which a bifunctional hydroxyl compound can be easily obtained.

  Examples of the bifunctional epoxy compound include polyglycidyl ether compounds of mononuclear dihydric phenol compounds such as hydroquinone, resorcin, and pyrocatechol; dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis (orthocresol), and ethylidene bisphenol. Isopropylidenebisphenol (bisphenol A), isopropylidenebis (orthocresol), tetrabromobisphenol A, 1,3-bis (4-hydroxycumylbenzene), 1,4-bis (4-hydroxycumylbenzene), Polyglycidyl ether compounds of polynuclear dihydric phenols such as thiobisphenol, sulfobisphenol, oxybisphenol; ethylene glycol, propylene glycol, Glycol, hexanediol, polyglycol, thiodiglycol, bisphenol A- polyglycidyl ethers of polyhydric alcohols such as ethylene oxide adducts. In the present invention, among these epoxy compounds, it is particularly preferable to use diglycidyl ether of bisphenol A or F from the viewpoint of obtaining a compound having good workability such as low viscosity.

The unsaturated carboxylic acid (a2 ) used in the present invention is a drying oil, semi-drying oil or modified oil of which iodine value is 100 or more, linseed oil, safflower oil, poppy oil, tung oil, walnut Oil, soybean oil, rapeseed oil and the like, or modified oils thereof. Among them, compounds such as linoleic acid type, linolenic acid type, and eicosapentaenoic acid that contain many unsaturated double bonds are accelerated by oxidative polymerization, and the cross-linking density of the coating film is increased accordingly. It is preferable because of improved properties. In particular, from the viewpoint of practicality, it is preferable to use a highly conjugated linoleic acid-based unsaturated carboxylic acid.

  Specific examples of the hydroxyl group-containing compound (A1) obtained by reacting the unsaturated carboxylic acid (a2) with the epoxy compound (a1) include the following compounds No. 1 to No. 7. . However, the present invention is not limited by these compounds.

Compound No.1

Compound No. 2

Compound No. 3

Compound No. 4

Compound No. 5

Compound No. 6

Compound No. 7

  Moreover, it is preferable that the usage-amount of the said hydroxyl-containing compound (A1) is the quantity used as 5.0-65.0 mass% of the said polyol component (A), The range of 25.0-45.0 mass% is preferable. It is more preferable that When the amount used is less than 5.0% by mass, the effects of drying and barrier properties are small, and when it exceeds 65.0% by mass, sufficient coating properties such as cracking of the coating cannot be obtained. Therefore, it is not preferable.

  Examples of the polyol (A2) having 2 or 3 hydroxyl groups and a number average molecular weight of less than 500 used in the present invention include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl- 1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9 Nonanediol, 1,10-decanediol, aliphatic diol compounds such as diethylene glycol, triethylene glycol, dipropylene glycol; cycloaliphatic diol compounds such as cyclohexanedimethanol and cyclohexanediol; trimethylolethane, trimethylolpropane, glycerin, etc. These trivalent alcohol compounds are mentioned.

  In the present invention, these diols and methylene bisphenol, ethylidene bisphenol, butylidene bisphenol, isopropylidene bisphenol and other bisphenol compounds and triol compounds are substituted with alkylene oxides having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, butylene oxide). Added polyether polyols can also be used. Polyester polyols obtained by condensation reaction of diols and / or triol compounds with dibasic acids such as succinic acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid and isophthalic acid Can also be used.

  These can be used alone or in combination of several kinds. In particular, it is possible to use a compound having a lower molecular weight such as ethylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, trimethylolpropane, etc., with a small amount of urethane bond concentration or crosslinking. It is preferable because the density can be increased and a barrier effect can be easily exhibited.

  The use amount of the polyol (A2) having 2 or 3 hydroxyl groups and a number average molecular weight of less than 500 is preferably 0.5 to 35.0% by mass of the polyol component (A), and is preferably 1.0 to The range of 20.0% by mass is more preferable. If the amount used is less than 0.5% by mass, the urethane bond concentration and the crosslinking density are low and the desired barrier property cannot be obtained, and if it exceeds 35.0% by mass, a flexible coating film property cannot be obtained.

  Polyols, polyester polyols, polyester polycarbonate polyols, crystalline or non-crystalline are polyols (A3) having a positive number of 2 to 3 hydroxyl groups and a number average molecular weight of 500 to 5000 used in the present invention. Specific polycarbonate polyols, polybutadiene polyols, silicone polyols and the like. These may be used alone or in combination of two or more. In particular, when a polyester polyol is used, an aqueous polyurethane resin having excellent coating film properties is obtained, which is preferable. On the other hand, if the molecular weight is less than 500, the flexibility is inferior and the film-forming property becomes insufficient. If the molecular weight exceeds 5000, the urethane bond concentration and the crosslinking density are too small, so that the object of the present invention cannot be achieved. It is particularly preferable to use a polyol having a molecular weight of 1000 to 2000 in terms of the balance with the physical properties of the coating film.

  Examples of the polyether polyols include polyether polyols and polytetramethylene ether glycols in which alkylene oxides having 2 to 4 carbon atoms (ethylene oxide, propylene oxide, butylene oxide) are added to the compound (A2).

  Examples of the polyester polyols include the diol and / or triol compound exemplified in (A2) above, an ester-forming derivative such as a polycarboxylic acid having an amount less than the stoichiometric amount or an ester, anhydride or halide thereof, and And / or those obtained by direct esterification and / or transesterification with a hydroxycarboxylic acid obtained by hydrolytic ring-opening of lactones. Examples of the polyvalent carboxylic acid or its ester-forming derivative include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid 2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid, hydrogenated dimer acid, Aliphatic dicarboxylic acids such as dimer acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; trimellitic acid, trimesic acid, castor oil fatty acid Polycarboxylic acids such as tetracarboxylic acids such as pyromellitic acid Examples of the ester-forming derivatives thereof include acid anhydrides of these polycarboxylic acids, halides such as polyvalent carboxylic acid chlorides and bromides; methyl esters, ethyl esters, propyl esters, and isopropyls of the polyvalent carboxylic acids. Examples include lower aliphatic esters such as esters, butyl esters, isobutyl esters, and amyl esters.

  Moreover, the usage-amount of the polyol (A3) of the said number average molecular weight 500-5000 of the positive number of the said hydroxyl group functional groups 2-3 is 10.0-80.0 mass% as a mass% ratio in the said polyol component (A). Is preferable, and the range of 20.0-45.0 mass% is more preferable. When the ratio is less than 10.0% by mass, it is not preferable because sufficient film properties cannot be obtained, and when it exceeds 80.0% by mass, the barrier property is impaired as the crosslinking density is decreased.

  Examples of the anionic group-containing polyol (A4) compound include polyols containing a carboxyl group such as dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolbutyric acid, dimethylolvaleric acid, and 1,4-butanediol-2. -Polyols containing a sulfonic acid group such as sulfonic acid can be mentioned. Particularly, when dimethylolpropionic acid or dimethylolbutanoic acid is used, it is preferable because of its excellent dispersibility in water.

  Moreover, it is preferable that the usage-amount of the said anionic group containing polyol (A4) is 1.0-25.0 mass% of the said polyol component (A), In the range of 5.0-15.0 mass%. More preferably. If the amount used is less than 1.0% by mass, the amount of the hydrophilic group is insufficient and water dispersion becomes difficult, which is not preferable. Exceeding 25.0% by mass is not preferable because it causes a decrease in water resistance and film flexibility, or a decrease in workability associated with an increase in the viscosity of the prepolymer.

  As described above, the anionic group-containing polyol (A4) has a function of imparting self-emulsifying properties to the polyurethane resin. It is necessary to neutralize the anionicity with a compatibilizer. Examples of the neutralizing agent used in this case include organic amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine, and triethanolamine, and sodium hydroxide, potassium hydroxide, ammonia, and the like. An inorganic base is mentioned. These are used in an amount sufficient to neutralize the anionicity.

  Examples of the aromatic isocyanate (B1) compound used in the present invention include 2,4- and / or 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, 1, Diisocyanate compounds such as 5-naphthylene diisocyanate, 3,3′-dimethyldiphenyl-4,4′-diisocyanate, dianisidine diisocyanate, tetramethylxylylene diisocyanate, triphenylmethane triisocyanate, 1-methylbenzole-2,4, Examples thereof include trifunctional or higher functional isocyanates such as 6-triisocyanate and dimethyltriphenylmethane tetraisocyanate. In the present invention, 2,4- and / or 2,6-tolylene diisocyanate is particularly preferable when the urethane bond concentration is increased, since it has excellent barrier properties and excellent coating film properties.

  The amount of the aromatic isocyanate (B1) used is preferably such that the isocyanate group equivalent ratio (NCO / OH) to the hydroxyl equivalent of the polyol component (A) is in the range of 0.5 to 0.95. A range of 8 to 0.9 is more preferable. If the NCO / OH ratio is less than 0.5, the ratio of aromatic isocyanate in the urethane prepolymer is too small, so that the barrier effect is reduced. On the other hand, when the ratio is more than 0.95 and less than 1.0, the prepolymer has a high molecular weight and a high viscosity, which makes it difficult to produce. Further, when the ratio is 1.0 or more, the end of the prepolymer becomes an aromatic isocyanate group and the end cannot be reacted with aliphatic or alicyclic isocyanate (B2), so that the effect of the present invention is exhibited. I can't.

  Examples of the aliphatic or alicyclic isocyanate compound (B2) used in the present invention include alicyclic diisocyanates such as isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, trans-1,4-cyclohexyl diisocyanate, and norbornene diisocyanate; , 6-hexamethylene diisocyanate, 2,2,4 and / or (2,4,4) -trimethylhexamethylene diisocyanate, lysine diisocyanate and the like. In the present invention, among these, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate are preferable, and isophorone diisocyanate is particularly preferable because of excellent coating performance.

  The amount of the aliphatic and / or alicyclic isocyanate (B2) used is (B2) relative to the hydroxyl equivalent of the terminal hydroxyl group prepolymer obtained by the reaction of the polyol component (A) and the aromatic isocyanate (B1). ) The isocyanate group equivalent ratio (NCO / OH) is preferably in the range of 1.05 to 5.0, and more preferably in the range of 1.2 to 3.0. An NCO / OH ratio of less than 1.05 is not preferred because the prepolymer has a high molecular weight and thus becomes highly viscous and difficult to produce. On the other hand, if the NCO / OH ratio is greater than 5.0, the number of residual isocyanate groups increases, which causes foaming due to reaction with water during water dispersion or deterioration of coating film properties due to an increase in urea bonds, which is not preferable.

  In the reaction of the aromatic isocyanate component (B1) and the aliphatic and / or alicyclic isocyanate component (B2) with the polyol component (A), the components (B1) and (B2) are combined with the component (A). In general, since the (B1) compound has a higher reaction activity than the (B2) compound, most of the end groups of the prepolymer become the (B2) compound, but some of the prepolymer ends are (B1). ) May be a compound. In this case, since there is a tendency to cause deterioration of coating film properties due to foaming during water dispersion and an increase in urea bond, in the present invention, the component (B1) is first reacted to synthesize a urethane prepolymer having a terminal hydroxyl group. After this, it is more preferable to react the component (B2) with this terminal hydroxyl group urethane polymer.

  In addition, as the (B1) and (B2) isocyanate compounds, the above-mentioned diisocyanate isocyanurate trimers, burette trimers, trimethylolpropane adducts, and carbodiimide-modified products can be used alone or in combination. Alternatively, it may be used in the form of a blocked isocyanate blocked with various blocking agents.

  In the urethane resin of the present invention, as described above, the polyol component (A) and the aromatic isocyanate component (B1) are reacted to first synthesize a prepolymer having a terminal hydroxyl group, and then the aliphatic polymer and / or the prepolymer is further synthesized. The alicyclic isocyanate (B2) is reacted to form a prepolymer having a terminal aliphatic or alicyclic isocyanate.

  The aromatic isocyanate (B1) functions effectively for improving the barrier properties, but in the case of the aliphatic and / or alicyclic isocyanate (B2), this performance is inferior, while the aromatic isocyanate compound has an isocyanate activity. Therefore, when the prepolymer is dispersed, it easily reacts with water to generate carbon dioxide and cause foaming, as well as causing deterioration of coating film properties due to urea formation. It is not preferable to disperse. Therefore, in the present invention, the above-mentioned problems are solved by using aliphatic or cycloaliphatic isocyanate at the end of the prepolymer.

  Examples of the chain extender component (C) compound used in the present invention include a low molecular weight polyol having a molecular weight of 200 or less and a low molecular weight polyamine. Examples of the low molecular weight polyol include compounds having a molecular weight of 200 or less in the compounds exemplified as the polyol (A2) having 2 or 3 hydroxyl groups and a number average molecular weight of less than 500. Examples of the low molecular weight polyamine include ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, melamine, and succinic acid dihydrazide. , Adipic acid dihydrazide, phthalic acid dihydrazide and the like.

  The amount of these chain extenders used is usually 0.05 to 1.0 times the amount of residual isocyanate equivalent of the prepolymer dispersed in water, although it depends on the molecular weight of the target polyurethane resin. . If the amount exceeds 1.0 times, the residual amount of the chain extender monomer is increased, and the physical properties of the coating film tend to be lowered, which is not preferable.

  The method for producing the solvent-free aqueous polyurethane composition of the present invention is a production method in which a urethane prepolymer is synthesized in a methyl ethyl ketone solvent, diluted with an acetone solvent, and dispersed in water, followed by removing the solvent. is there. As a general method for obtaining an aqueous dispersion of a polyurethane resin, for example, a prepolymer is synthesized from a polyol component (A) and an isocyanate component (B), poured into water and dispersed, and then chain extended in water. A prepolymer is synthesized using the method (a) in which the agent component (C) is reacted, the polyol component (A), the isocyanate component (B), and the chain extender component (C) at the same time, and this is poured into water and dispersed. (B), a prepolymer is synthesized from the polyol component (A) and the isocyanate component (B), water is poured into the prepolymer to obtain an aqueous dispersion, and then the chain extender component (C) is reacted. After synthesizing a prepolymer using the method (c), the polyol component (A), the isocyanate component (B), and the chain extender component (C) at the same time, water is poured into the prepolymer and dispersed. Law (d), and the like. In the present invention, in the cases of (b), (c) and (d), the viscosity of the prepolymer tends to be high and dispersion tends to be difficult. A method of increasing the molecular weight in water after addition to obtain an aqueous dispersion is particularly preferred.

As a solvent used when producing the urethane prepolymer of the present invention, an organic solvent which is inert to the reaction and has a high affinity with water and the urethane prepolymer is preferable. Examples of such a solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, dioxane, tetrahydrofuran, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and ethyl acetate.
In the present invention, among these solvents, it is preferable to use a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone and the like having a relatively low boiling point because of the solubility of the urethane resin and the ease of desolvation after water dispersion.

  In the present invention, from the viewpoint of the efficiency of the solvent removal step, it is preferable to use a solvent having a boiling point lower than that of water. However, if the boiling point is too low, it is not easy to raise the reaction temperature, and the urethanization reaction takes time. Therefore, it is inappropriate to use acetone as a reaction solvent, and it is most preferable to use methyl ethyl ketone.

  However, when methyl ethyl ketone is used as the reaction solvent, the urethane prepolymer has a water-dispersed particle size because the solubility in urethane resin derived from the solubility parameter (SP value) of methyl ethyl ketone and water is inferior to acetone. Has a drawback that the dispersion becomes high in viscosity.

  Therefore, in the present invention, after performing the urethanization reaction in a methyl ethyl ketone solvent, by dispersing in water the prepolymer obtained by adding acetone, which is more soluble in urethane resin and water than methyl ethyl ketone, An aqueous polyurethane resin composition having a small particle size and low viscosity is obtained. As described above, in the present invention, methylethylketone was used as a urethanization reaction solvent (hereinafter referred to as a reaction solvent), and acetone was added after the reaction (hereinafter referred to as an aqueous dispersion solvent) to disperse in water, thereby achieving excellent stability. The solventless aqueous polyurethane resin composition of the present invention can be obtained.

  The amount of the reaction solvent and the aqueous dispersion solvent used is usually 10 to 100% by mass based on the total weight of the raw materials used for producing the prepolymer. Moreover, it is preferable that it is 70 / 30-90 / 10 (reaction solvent / water dispersion solvent) by mass ratio, and the usage-amount of the said reaction solvent and water dispersion solvent is 75 / 25-85 / 15 mass ratio. Is more preferable. If the (reaction solvent / water dispersion solvent) ratio is 70/30 or less, the prepolymer during the urethanization reaction has a high viscosity, which hinders workability, and the (reaction solvent / water dispersion solvent) ratio is 90/30. If it is 10 or more (the aqueous dispersion solvent is less than 10 mass ratio), the effect of reducing the particle size is small, such being undesirable.

  The solvent-free aqueous polyurethane resin composition of the present invention thus obtained is usually adjusted so that the resin solid content is 5 to 80% by mass, preferably 10 to 70% by mass. When the resin solid content is less than 5% by mass, it takes a long time to dry because it contains a large amount of water, and when the resin solid content exceeds 80% by mass, the viscosity becomes high and handling is difficult. This is not preferable.

  The urethane prepolymer of the present invention can be used in combination with a known melamine compound used for polyurethane as a crosslinking agent. Examples of such melamine compounds include melamine, monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine, methylated methylol melamine, butylated methylol melamine, melamine resin and the like. . In the present invention, melamine is particularly preferable because it is excellent in dispersibility of the aqueous polyurethane composition.

  The solventless water-based polyurethane resin composition of the present invention is a compound that can react with an anionic group (specifically, a carboxyl group or a sulfonic acid group) for the purpose of further improving the water resistance. It can also be used as an agent. Specific examples of the compound that can react with an anionic group include an oxazoline compound, an epoxy compound, a carbodiimide compound, an aziridine compound, a melamine compound, and a zinc complex. Among these, in the present invention, an oxazoline compound, an epoxy compound, and a carbodiimide compound that can easily react with an anionic group are preferable.

  In addition, the solvent-free aqueous polyurethane resin composition of the present invention includes, as necessary, a phenolic antioxidant, an organic phosphorus antioxidant such as an organic phosphite or phosphonite, a thioether antioxidant, and an ultraviolet absorber. Alternatively, a light stabilizer such as a hindered amine compound can be added.

  Examples of the phenol-based antioxidant that can be used in the present invention include 2,6-ditert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate, thiodiethylenebis [(3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate], 4,4′-thiobis (6-tert-butyl-m-cresol), 2-octylthio-4,6-di (3,5-ditert-butyl-4-hydroxyphenoxy) -s-triazine 2,2′-methylenebis (4-methyl-6-tert-butylphenol), bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) Butyric acid] glycol ester, 4,4′-butylidenebis (6-tert-butyl-m-cresol), 2,2′-ethylidenebis (4,6-ditert-butylphenol), 1,1,3-tris (2-Methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] Terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxy Benzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris [(3 -Di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 2-tert-butyl-4 -Methyl-6- (2-acryloyloxy-3-tert-butyl-5-methylbenzyl) phenol, 3,9-bis [1,1-dimethyl-2-hydroxyethyl) -2,4,8,10- Tetraoxaspiro [5,5] undecane-bis [β- (3-tert-butyl-4-hydroxy-5-butylphenyl) propionate], triethylene glycol bis [β- (3-tert-butyl-4-hydroxy -5-methylphenyl) propionate] and the like.

  Examples of the organophosphorus antioxidant that can be used in the present invention include trisnonylphenyl phosphite, tris (monodinonylphenyl) phosphite, and tris (2,4-ditert-butylphenyl) phosphite. , Di (tridecyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, bis (2,4-ditert-butylphenyl) pentaerythritol diphosphite, bis (2,6-ditert-butyl-4- Methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tritert-butylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (tridecyl) -4,4 ′ -N-butylidenebis (2-tert-butyl-5 Methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (3-tert-butyl-4-hydroxy-5-methylphenyl) butanetriphosphite, 2,2′-methylenebis (4,6-diter Tributylphenyl) octyl phosphite, 2,2′-methylenebis (4,6-ditert-butylphenyl) octadecyl phosphite, 2,2′-methylenebis (4,6-ditert-butylphenyl) fluorophosphite, Examples include tetrakis (2,4-ditert-butylphenyl) biphenylene diphosphonite, 9,10-dihydro-9-oxa-10 phosphaphenanthrene-10-oxide.

  Examples of thioether-based antioxidants include dialkylthiodipropionates such as dilauryl, dimyristyl, myristylstearyl, and distearyl esters of thiodipropionic acid, and polyols such as pentaerythritol tetra (β-dodecylmercaptopropionate). β-alkyl mercaptopropionic acid esters and the like can be mentioned.

  Examples of the ultraviolet absorber that can be used in the present invention include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis ( 2-hydroxybenzophenones such as 2-hydroxy-4-methoxybenzophenone); 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2 -(2-hydroxy-3,5-ditert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, , 2′-methylenebis (4-tert-octyl-6-benzotriazolyl) phenol, 2- (2-hydroxy-3-tert-butyl-5-carboxyphenyl) benzotriazole polyethylene glycol ester and the like 2- ( 2-hydroxyphenyl) benzotriazoles; phenyl salicylate, resorcinol monobenzoate, 2,4-ditert-butylphenyl-3,5-ditert-butyl-4-hydroxybenzoate, hexadecyl-3,5-ditert-butyl Benzoates such as -4-hydroxybenzoate; substituted oxanilides such as 2-ethyl-2'-ethoxyoxanilide and 2-ethoxy-4'-dodecyloxanilide; ethyl-α-cyano-β, β-diphenyl Acrylate, methyl-2-cyano-3-methyl-3- (p-me Kishifeniru) acrylate and the like cyanoacrylates such as.

  Examples of the light stabilizer such as the hindered amine compound that can be used in the present invention include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl- 4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6 , 6-Pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) ) Butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) .di (tridecyl) -1,2,3,4 Butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2-butyl-2- (3,5-ditert-butyl-4-hydroxybenzyl) malonate, 1- ( 2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis (2,2,6,6-tetraethyl-4-piperidylamino) hexane / Dibromoethane polycondensate, 1,6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1, 6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-tert-octylamino-s-triazine polycondensate, 1,5,8,12- Trakis [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8,12- Tetraazadodecane, 1,5,8,12-tetrakis [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazine- 6-yl] -1,5,8,12-tetraazadodecane, 1,6,11-tris [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4 -Piperidyl) amino) -s-triazin-6-ylamino] undecane, 1,6,11-tris [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4) -Piperidyl) amino) -s-triazin-6-ylamino] undecane, etc. Hindered amine compounds.

  The solventless aqueous polyurethane resin composition of the present invention includes a colorant, a wax, a preservative, an antifoaming agent, a plasticizer, a filler, a solvent, a film-forming aid, a dispersant, and a thickener depending on the purpose. Conventional additives such as fragrances can also be added.

  The solvent-free water-based polyurethane resin composition of the present invention can be used for other water-based resin emulsions, for example, synthetic resin emulsion natural rubber such as polyvinyl acetate, ethylene vinyl acetate copolymer, acrylic resin, rubber such as SBR, NBR, etc. Since compatibility with latex is good, it is also useful as these modifiers.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited at all by these Examples.

[Example 1-1]
<Synthesis of Prepolymer 1>
350 g (0.79 eq) of Compound No. 5 as the hydroxyl group-containing compound (A1) polyol, 200 g (3.85 eq) of neopentyl glycol (hereinafter referred to as NPG) as the polyol (A2) component, and average as the polyol (A3) component NPG having a molecular weight of 1000 and AA (adipic acid) polyester polyol (manufactured by ADEKA, product name Adeka New Ace Y9-10) 350 g (0.70 eq), dimethylolpropionic acid (A4) as an anionic group-containing polyol (A4) Hereinafter, DMPA) is 100 g (1.49 eq), and aromatic diisocyanate (B1) component is tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name T-80: hereinafter referred to as TDI) 535 g (6.15 eq). ) (NCO / OH equivalent ratio = 0.90), methyl ethyl as the reaction solvent Ketone (hereinafter, referred to as MEK) were mixed 941 g, at 80-85 ° C. under a nitrogen inlet, to obtain a prepolymer 1 was reacted for 3 hours until the NCO group disappeared.

<Synthesis of Prepolymer 2>
The prepolymer 1 obtained above is cooled to 50 ° C., and 212 g (1.91 eq: NCO / N) of isophorone diisocyanate (hereinafter referred to as IPDI) is used as an aliphatic and / or alicyclic isocyanate (B2) component under nitrogen introduction. OH equivalent ratio = 2.80) was added, and the mixture was reacted at 80 to 85 ° C. under nitrogen introduction for 2.5 hours until the designed NCO content was reached, thereby obtaining Prepolymer 2.

<Preparation of prepolymer 3>
The prepolymer 2 obtained above was set at 55 ° C., and under nitrogen introduction, 224 g of acetone as a dispersion solvent and 68.0 g (0.67 eq: prepolymer) of triethylamine (hereinafter referred to as TEA) as a neutralizing agent for anionic groups 0.9 eq) with respect to 2 anionic groups, 1.7 g (0.0025 mol) of octix manganese (Mn8%) were added, and the mixture was stirred at 55 to 65 ° C. for 20 minutes to prepare Prepolymer 3.

<Preparation of polyurethane resin emulsion>
1000 g of the above three urethane prepolymer components set at 60 ° C. were added to 1333 g of deionized water at 35 ° C. (amount of solid content after desolvation of 30.0%) over 15 minutes while stirring and mixing. Aging at ˜40 ° C. for 20 minutes. Next, 7.9 g of ethylenediamine (hereinafter referred to as EDA) (0.26 eq: 0.6 eq with respect to the remaining NCO group of the prepolymer 2) was reacted as a chain extender (C) component to increase the molecular weight, and then 35 to 40 ° C. For 30 minutes. Next, the solvent was removed under conditions of 40 to 45 ° C./8 kPa for 3 to 4 hours to obtain an aqueous polyurethane resin composition. The residual solvent amount was quantified by GC (gas chromatography analysis), and it was confirmed that no peak of each solvent was detected. In addition, said eq notation means an equivalent and represents the number of equivalents, such as a hydroxyl group, an isocyanate group, and an amine group, respectively.

[Examples 1-2 to 1-13]
[Table 1] As described in Example 1-1, except that the NCO / OH equivalent ratio and the prepolymer solid content were kept constant and the composition ratios of components (A1) to (A4) were changed. An aqueous polyurethane resin was prepared by the method described above. The following test was done using the obtained water-based polyurethane resin composition. The results are shown in the following [Table 1] and [Table 2].

[Example 1-14]
As shown in [Table 2], after reacting with EDA as a chain extender (C) component, adipic acid dihydrazide (hereinafter referred to as ADH) 0.3 eq (11.3 g) with respect to the remaining NCO groups of prepolymer 2 : 0.13 eq) was used together to prepare an aqueous polyurethane resin by the same method as in Example 1-1. The following test was done using the obtained water-based polyurethane resin composition. The results are shown in the following [Table 2].

[Examples 2-1 to 2-2]
As shown in Table 3, the aliphatic and / or alicyclic isocyanate component (B2) was changed to 4-4′-dicyclohexylmethane diisocyanate (H ₁₂ MDI) and hexamethylene diisocyanate (HDI), respectively. Except for the above (the NCO / OH equivalent ratio and the prepolymer solid content are constant), an aqueous polyurethane resin was prepared by the same method as in Example 1-1. The following test was done using the obtained water-based polyurethane resin composition. The results are also shown in the following [Table 3].

[Example 2-3]
As shown in [Table 3], the NCO / OH equivalent ratio of the aromatic isocyanate component (B1) and the aliphatic and / or alicyclic isocyanate component (B2) was changed [(B1) NCO / OH equivalent ratio 0. .70, (B2) NCO / OH equivalent ratio 1.50] (prepolymer solid content is constant), an aqueous polyurethane resin was prepared in the same manner as in Example 1-1. The following test was done using the obtained water-based polyurethane resin composition. The results are also shown in [Table 3] below.

[Comparative Examples 1-1 to 1-8]
[Table 4] As described in the formulation, (A1) to (A4) Except for changing the component composition ratio (the NCO / OH equivalent ratio and the prepolymer solid content are constant), the same as in Example 1-1 above An aqueous polyurethane resin was prepared by the method. The following test was done using the obtained water-based polyurethane resin composition. The results are also shown in the following [Table 4].

[Comparative Examples 2-1 and 2-2]
As shown in [Table 5], except for changing the component (B) (the NCO / OH equivalent ratio and the prepolymer solid content are constant), the aqueous polyurethane resin was prepared in the same manner as in Example 1-1. Prepared. The following test was done using the obtained water-based polyurethane resin composition. The results are shown in the following [Table 5].

[Comparative Examples 3-1 to 3-3]
[Table 6] A water-based polyurethane resin was prepared in the same manner as in Example 1-1 except that the solvent was changed as described in the formulation. The following test was done using the obtained water-based polyurethane resin composition. The results are shown in the following [Table 6].

[Property value]
<Viscosity>
Measured with a BM viscometer. (Unit: mPa · s / 25 ° C)
<PH>
Measured using a pH meter. (At 25 ° C)
<NV (solid content)>
About 2 g of water-based urethane resin was precisely weighed on an aluminum dish, and after removing volatile matter at 150 ° C. for 2 hours, the remaining amount was precisely weighed to calculate the solid content (unit:%).
<Particle size>
The average particle size was measured (unit: nm) using a laser diffraction particle size distribution analyzer (SALAD-2000, manufactured by Shimadzu Corporation).

[Evaluation]
<Preparation of test coating film>
A polyurethane resin composition for evaluation was applied on a glass plate using a bar coater so that the film thickness was 100 μm, and then dried at 25 ° C. for 24 hours to prepare a test coating film.
<Water resistance>
The test coating piece was immersed in water for 24 hours, and the water-whitening state was visually observed. Those that did not change at all were marked with ◎, those with very little whitening were marked with ○, those that were whitened (transparent) were marked with Δ, and those that were whitened (white turbidity) were marked with ×.
<Ethanol resistance>
Using the Kanakin No. 3 friction cloth, the test coating film surface was subjected to 10 reciprocating ethanol rubbing with a load of 500 g, and the appearance was visually evaluated.
The case where there was no change in appearance was indicated by ◎, the case where slight gloss change or the like was caused was indicated by ◯, the case having surface stickiness was indicated by Δ, and the case where 50% or more was dissolved or peeled was indicated by ×.

<Alkali resistance>
The test coating piece was immersed in a 5% NaOH aqueous solution for 30 minutes, and the coating state was visually evaluated. A sample having no change in appearance was indicated by ◎, a sample having a slight discoloration on the surface, a symbol Δ indicating a slight stickiness on the surface, and a symbol X indicating that the surface was dissolved.
<Drying property (touch drying)>
After applying the water-based polyurethane resin composition for evaluation on a glass plate so that the film thickness becomes 100 μm using a bar coater, it can be touched with a finger in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 75%. The time until the coating film did not stick to the finger (drying time for finger touch) was measured.
<Pencil hardness>
The pencil hardness was measured according to JIS K 5600 with respect to the test coating film.

* In the table, the numerical value of the composition indicates mass (g).

[A2 component]
NPG: Neopentyl glycol TMP: Trimethylolpropane [A3 component]
Y9-10: NPG + AA, MW: 1000 (manufactured by ADEKA)
Y9-20: NPG + AA, Mw: 2000 (manufactured by ADEKA)
F1212-5: 1,6-HD (1,6-hexanediol) + AA / iPA (isophthalic acid), Mw: 2000 (manufactured by ADEKA)
PTG2000SN: PTMEG (polytetramethylene ether glycol) diol, Mw: 2000 (manufactured by Hodogaya Chemical Co., Ltd.)
[A4 component]
DMPA: dimethylolpropionic acid DMBA: dimethylolbutanoic acid

[B1 component]
TDI: Tolylene diisocyanate [B2 component]
IPDI: isophorone diisocyanate H ₁₂ MDI; 4-4′-dicyclohexylmethane diisocyanate HDI; hexamethylene diisocyanate [solvent] MEK: methyl ethyl ketone

* In the table, the numerical value of the composition indicates mass (g).
* 1; [Component (C)] E: EDA (ethylenediamine), A: ADH (adipic acid dihydrazide)

* In the table, the numerical value of the composition indicates mass (g).

* In the table, the numerical value of the composition indicates mass (g).
* 1; Water dispersible: Not dispersed due to lack of hydrophilicity
* 2: Water dispersion impossible: Prepolymer high viscosity makes water dispersion difficult
* 3; Evaluation not possible: Evaluation is not possible because a coating film test piece cannot be obtained due to cracking when the coating film dries.

* 1: In the table, the numerical value of the composition indicates mass (g).
* 2: In the table, the numerical value of component (B) is shown separately for the amounts used for the synthesis of prepolymer 1 and prepolymer 2.

* In the table, the numerical value of the composition indicates mass (g).
[Solvent] NMP: N-methyl-2-pyrrolidone

  From the above results, it is apparent that a coating composition having excellent properties and evaluation can be obtained only by the composition and the production method of the present invention.

  The present invention relates to a solvent-free aqueous polyurethane resin composition excellent in barrier properties (water resistance, solvent resistance (alcohol) resistance and alkali resistance) of coating film and room temperature drying property, and production of the composition excellent in production suitability. A method can be provided.

Claims (7)

The polyol component (A) and the isocyanate component (B) are reacted in a methyl ethyl ketone solvent to prepare a urethane prepolymer having a terminal aliphatic or alicyclic isocyanate, which is diluted with an acetone solvent and then dispersed in water. Then, a solvent-free aqueous polyurethane resin composition obtained by removing the solvent, wherein the polyol component (A) is added to an epoxy compound (a1) having 1 to 3 epoxy groups in one molecule, linseed oil, safflower oil, poppy seed oil, tung oil, walnut oil, soybean oil and rapeseed Abura及 beauty hydroxyl group-containing compound obtained by reacting at least one unsaturated carboxylic acid selected from these modified oils (a2) (A1), the number of hydroxyl groups 2 Or a polyol (A2) having a number average molecular weight of less than 500 in 3, a positive number having a hydroxyl number of 2 to 3 and a number average molecular weight of 500 to 5000 (A3), and Isocyanate having an anionic group-containing polyol (A4) as an essential component, and the isocyanate component (B) having an aromatic isocyanate (B1) and an aliphatic and / or alicyclic isocyanate (B2) as essential components The ratio of each component in the polyol component (A) is (A1) 5.0 to 65.0 mass%, (A2) 0.5 to 35.0 mass%, and (A3) 10. A solvent-free aqueous polyurethane resin composition characterized by being in the range of 0 to 80.0% by mass and (A4) 1.0 to 25.0% by mass.   The solvent-free aqueous polyurethane resin composition according to claim 1, wherein the aromatic isocyanate (B1) is tolylene diisocyanate.   The aliphatic and / or alicyclic isocyanate (B2) is at least one selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, and 4-4'-dicyclohexylmethane diisocyanate. Solvent-free aqueous polyurethane resin composition.   The solventless aqueous system according to any one of claims 1 to 3, wherein the epoxy compound (a1) having 1 to 3 epoxy groups in one molecule is diglycidyl ether of bisphenol A and / or bisphenol F. Polyurethane resin composition.   The solvent-free aqueous polyurethane resin composition according to any one of claims 1 to 4, wherein the anionic group-containing polyol (A4) is dimethylolpropionic acid and / or dimethylolbutanoic acid.   A solventless aqueous polyurethane resin composition obtained by further increasing the molecular weight of the solventless aqueous polyurethane resin according to any one of claims 1 to 5 using a chain extender (C). The epoxy compound having one to three epoxy groups in one molecule (a1), linseed oil, safflower oil, poppy oil, tung oil, walnut oil, at least one selected from soybean oil and rapeseed Abura及 beauty these modified oils Hydroxyl group-containing compound (A1) obtained by reacting an unsaturated carboxylic acid (a2), a polyol (A2) having 2 or 3 hydroxyl groups and a number average molecular weight of less than 500, a positive number number average of 2 to 3 hydroxyl groups A polyol component (A) having a molecular weight of 500 to 5000 as an essential component, and a polyol component (A) having an anionic group-containing polyol (A4), the proportion of each component is (A1) 5.0 to 65.0% by mass. , (A2) 0.5-35.0% by mass, (A3) 10.0-80.0% by mass, and (A4) 1.0-25.0% by mass, Aromatic isocyanate (B1) and fat And / or an isocyanate component (B) containing alicyclic isocyanate (B2) as an essential component in a methyl ethyl ketone solvent to prepare a urethane prepolymer having a terminal aliphatic or alicyclic isocyanate, and further using an acetone solvent. A method for producing a solvent-free aqueous polyurethane resin, wherein the solvent is dispersed after water dilution and then the solvent is removed.