JP2002128851A - Thermal crosslinking aqueous polyurethane resin composition and nonwoven fabric reinforcing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-component thermal crosslinking aqueous polyurethane resin composition excellent in film forming ability, developing performance such as solvent resistance, having a low solvent vaporizing property, non-flammable, and excellent in a storage stability. SOLUTION: A urethane prepolymer is obtained by a reaction of a compound (A) having two or more of active hydrogen atoms, a carboxy group containing compound (B) having at least two hydroxy groups, an organic polyisocyanate (C) and a blocking agent (D), and contains a blocked isocyanate group in 2 to 18 wt.% equivalent to a recovered isocyanate group. The thermal crosslinking aqueous polyurethane resin composition contains a polyurethane resin (E) having a weight average molecular weight of 1,500 to 50,000 obtained by dispersing the urethane prepolymer in water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-crosslinkable water-based polyurethane resin composition having latent crosslinking properties which is one-packed and has excellent storage stability. It can exhibit excellent adhesion, heat resistance, solvent resistance, chemical resistance, and water resistance, and can be applied to a wide range of fields as adhesives, coating agents, paints, modifiers, and binders. A thermally crosslinkable water-based polyurethane resin that can be suitably used as a reinforcing agent for a nonwoven fabric made of various synthetic fibers such as vinylon, polyester, nylon, and rayon, and is particularly useful as a nonwoven fabric reinforcing agent for polyester fibers having difficulty in developing adhesion. Composition.

[0002]

2. Description of the Related Art Aqueous polyurethane resins have conventionally been useful materials as adhesives, coating agents, paints, modifiers, binders and the like, and have been used in a wide variety of applications.
Such an aqueous polyurethane resin is self-emulsified and dispersed by introducing a hydrophilic group such as anionic, cationic, or nonionic into the urethane resin skeleton, or a surfactant is added to a hydrophobic urethane resin. And forcibly emulsified and dispersed.

[0003] Conventional aqueous polyurethane resins include the following two.
Can be roughly classified into two types. That is, the first
Is an aqueous polyurethane resin having a medium or high molecular weight linear or branched structure, and is used as an adhesive, a coating agent, or a binder. The second type is a low molecular weight blocked isocyanate group-containing heat-reactive water-based polyurethane resin, which is used as a modifier or a fiber processing agent for other types of emulsions.

[0004] However, the above-mentioned aqueous polyurethane resin having a medium or high molecular weight linear or branched structure has sufficient film-forming ability, but the film-forming mechanism is fusion between emulsion particles and urethane molecules. Since there was no bond due to cross-linking between them, it could not be said that performances such as solvent resistance, adhesion and heat resistance were sufficient.

The above-mentioned low molecular weight blocked isocyanate group-containing heat-reactive water-based polyurethane resin alone is inferior in film-forming ability and therefore unsuitable for use alone as an adhesive, coating agent, paint or binder. there were. Therefore, it is used as a modifier for the purpose of improving performance such as solvent resistance, adhesion, and heat resistance by being used in combination with a polymer emulsion having a medium to high molecular weight having a linear or branched structure. However, the crosslinking between the blocked isocyanate groups and the polymer emulsion was insufficient, and the above-mentioned performance improvement was limited.

For the purpose of improving the above-mentioned various properties, it has been studied to mix a melamine-based, epoxy-based, aziridine-based, carbodiimide-based, oxazolidine-based crosslinking agent with a carboxyl group-containing aqueous polyurethane resin. However, it is not preferable to mix the crosslinking agent with the carboxyl group-containing aqueous polyurethane resin as a one-part solution because of the problem of poor storage stability.

On the other hand, non-woven fabrics made of synthetic fibers such as vinylon, polyester, nylon, rayon, etc. are used for protecting clothing materials, clothing materials such as brass cup cores, shoulder pads, event jumpers, etc., experimental clothing, dust masks and the like. Furniture and interior materials such as clothing, carpets, carpet base cloth, etc., artificial leather base cloth, PVC leather base cloth etc. artificial leather,
Filters such as air filters and liquid filters, automotive interior materials such as floor mats, vehicle materials such as various filters for automobiles, abrasive materials, papermaking felts, industrial materials such as wire holding tapes, battery separators, etc. Civil and architectural materials such as water-blocking materials, roofing, condensation sheets, etc., agricultural and horticultural materials such as vinyl house sheets, light-shielding sheets, sticky sheets, storage bags, furoshiki, suit covers, tea bags, drainage sheets, etc. It is used in a wide range of fields such as medical materials such as materials, surgical gowns, cloth sets, birthing pads and caps, and sanitary materials such as disposable diapers, sanitary napkins, gauze, and wet tissues.

As these reinforcing agents, urethane resins,
Solvent-type resins such as polyester resin, acrylic resin, phenolic resin, melamine resin, and vinyl resin have been used. In recent years, as part of VOC regulations, environmentally friendly, nonflammable, aqueous urethane resin, aqueous polyester resin have been used. Water-based resins and water-soluble polymers such as polyvinyl alcohol resin, polyacrylamide, starch, SBR latex, chloroprene latex, NBR latex, vinyl acetate latex, acrylate latex, vinyl chloride latex, and vinylidene chloride latex are being studied.

However, in reality, it has not been possible to obtain a resin which satisfies all the properties such as adhesion to various synthetic fibers such as vinylon, polyester, nylon and rayon, solvent properties, heat resistance and water resistance. For this reason, studies have been made to mix a melamine-based, epoxy-based, aziridine-based, carbodiimide-based, oxazolidine-based crosslinker, etc., with a carboxyl group-containing aqueous resin. However, adhesion to various synthetic fibers, solvent properties, heat resistance, not only those still satisfying various performances such as water resistance have not yet been obtained, toxicity problems, and blended with the crosslinking agent. There is a problem that storage stability in the case of one liquid is inferior.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a film-forming ability which is excellent in solvent resistance, adhesion and heat resistance due to crosslinking. Provides a one-pack type heat-crosslinkable aqueous polyurethane resin composition that exhibits performance such as water resistance, has low solvent volatility, is nonflammable, and has excellent crosslinkability with excellent product stability. It is to be. Other objects of the present invention are adhesion to various synthetic fibers, solvent resistance, heat resistance, a nonwoven fabric reinforcing agent comprising the composition satisfying all of the advanced properties such as water resistance, especially filters, materials for vehicles, An object of the present invention is to provide a nonwoven fabric reinforcing agent useful for industrial materials, civil engineering and construction materials.

[0011]

Means for Solving the Problems In order to achieve the above-mentioned object, the heat-crosslinkable water-based polyurethane resin composition of the present invention comprises:
Obtained by reacting a compound (A) having two or more active hydrogen atoms, a carboxyl group-containing compound (B) having at least two or more hydroxyl groups, an organic polyisocyanate (C), and a blocking agent (D). Polyurethane having a weight average molecular weight of 1,500 to 50,000 obtained by dispersing a urethane prepolymer containing 2% by weight or more and 18 or less in terms of regenerated isocyanate groups in a molecule to be obtained in terms of regenerated isocyanate groups in water. It is characterized by containing a resin (E).

By using such a polyurethane resin (E), a sufficient film forming ability can be ensured, and a crosslinking reaction between the polyurethane resin and the adherend can be caused by heat treatment.

[0013] In the heat-crosslinkable water-based polyurethane resin composition of the present invention, the polyurethane resin (E) may have a 1,0 content.
The total number of aromatic ring groups and aliphatic ring groups represented by the following structural formulas 3 or 4 introduced from (A), (B) or (C) in the 00 atomic weight is 2 or more It is preferred that

[0014]

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[0015]

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As described above, it is preferable to introduce an aromatic ring group and an aliphatic ring group because the high cohesive force of these groups enhances heat resistance and develops solvent resistance, chemical resistance, and water resistance. Because you do.

In the heat-crosslinkable water-based polyurethane resin composition, the organic polyisocyanate (C) is an aromatic isocyanate, and the blocking agent (D) is an oxime-based blocking agent. It is preferable in performing a crosslinking reaction under a relatively low temperature heat treatment condition.

In the heat-crosslinkable water-based polyurethane resin composition of the present invention, the acid value of the carboxyl group in the urethane prepolymer is from 10 mgKOH / g to 60 mgKOH / g.
The range of mgKOH / g is preferable for improving emulsification / dispersion in water by a salt forming agent and adhesion to various synthetic fibers.

Further, the heat-crosslinkable water-based polyurethane resin composition of the present invention has at least two glycidyl groups on average in the molecule and has an epoxy equivalent of 110 to 300.
And an epoxy-based crosslinking agent having a water solubility of 20% or more is blended in a weight ratio of solid content of the polyurethane resin (E): the epoxy-based crosslinking agent = 100: 50 to 100: 5. Is preferred. By blending such an epoxy-based crosslinking agent, various properties such as heat resistance, solvent resistance, and water resistance can be further improved.

The nonwoven fabric reinforcing agent of the present invention is characterized by containing the above-mentioned heat-crosslinkable water-based polyurethane resin composition. Since the heat-crosslinkable aqueous polyurethane resin composition can cause a crosslinking reaction between the polyurethane resin and the adherend by heat treatment, it can be suitably used as a nonwoven fabric reinforcing agent.

[0021]

Embodiments of the present invention will be described below.

The water-crosslinkable water-based polyurethane resin composition of the present invention is obtained by emulsifying and dispersing a polyurethane resin (E) having a blocked isocyanate group in a side chain and / or a molecular terminal in water. In some cases, the polyurethane resin (E) may be emulsified, and then a part thereof may be made to have a high molecular weight by a reaction with a polyamine or water to be produced. The thermally crosslinkable water-based polyurethane resin composition according to the present invention may include the polyurethane resin (E) having a high molecular weight after emulsification in this way.

The polyurethane resin (E) according to the present invention
Is a compound (A) having two or more active hydrogen atoms,
A carboxyl group-containing compound (B) having at least two or more hydroxyl groups, an organic polyisocyanate (C),
It is obtained by reacting with a blocking agent (D) in the presence or absence of a solvent.

Compound (A) having the above active hydrogen atom
Is a compound having two or more hydroxyl groups, amino groups or mercapto groups at the terminal or in the molecule.
Specifically, it is a known polyether, polyester, polyetherester, polythioether, polyacetal, polybutadiene, polysiloxane, or the like, and is preferably a compound having two or more hydroxyl groups at a molecular terminal. The molecular weight of the compound having two or more active hydrogen atoms is preferably in the range of 50 to 5,000.

Specifically, the polyhydroxy compound having two or more active hydrogen atoms includes ethylene glycol, diethylene glycol, butanediol, propylene glycol, hexanediol, bisphenol A, bisphenol B, bisphenol S, hydrogenated bisphenol A, dibromobisphenol A, polyhydric alcohols such as 1,4-cyclohexanedimethanol, dihydroxyethyl terephthalate, hydroquinone dihydroxyethyl ether, trimethylolpropane, glycerin, pentaerythritol, alkylene derivatives thereof, or polyhydric alcohols and alkylene derivatives thereof And polyhydric carboxylic acid, polycarboxylic anhydride, or esterified product from polycarboxylic acid ester, polycarbonate polyol, polyester La glycol, polycaprolactone polyols, polybutadiene polyols, polythioether polyols, polyacetal polyols,
Examples thereof include polyol compounds such as fluorine polyols, silicone polyols, and castor oil polyols, and modified products thereof.

Next, as the carboxyl group-containing compound (B) having at least two hydroxyl groups, for example,
2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolpentanoic acid, 2,
Examples thereof include hydroxyalkanoic acids such as 2-dimethylolbutyric acid and 2,2-dimethylolvaleric acid. By using the carboxyl group-containing compound (B) having two or more hydroxyl groups for the introduction of the carboxyl group, the reaction with the isocyanate group is not too fast as compared with the case where an aminocarboxylic acid is used, and the reaction rate is reduced. There is an advantage that control is easy and a carboxyl group can be uniformly introduced into the molecule. The carboxyl group in the carboxyl group-containing compound (B) is for forming a salt with a salt forming agent when the obtained polyurethane resin (E) is dispersed in water. Examples of the salt forming agent include metal hydroxides such as sodium hydroxide and calcium hydroxide, and tertiary amine compounds such as ammonia, trimethylamine, triethylamine, and dimethylaminoethanol.

As the organic polyisocyanate (C) in the present invention, conventionally used organic polyisocyanates of aromatic, aliphatic, alicyclic and the like can be used, and specific examples thereof include naphthalene diisocyanate and isophorone diisocyanate. And organic polyisocyanates such as xylylene diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate, and mixtures thereof.

Examples of the blocking agent (D) include phenols such as phenol and cresol; alcohols such as methanol, ethanol and butyl cellosolve; lactams such as ε-caprolactam; methyl ethyl ketoxime;
Oximes such as cyclohexanone oxime; active methylenes such as dimethyl malonate and ethyl acetoacetate; imidazoles such as imidazole; and known blocking agents such as bisulfite and the like.

Among the combinations of the organic polyisocyanate (C) and the blocking agent (D), an aromatic isocyanate is used as the organic polyisocyanate (C), and an oxime blocking agent is used as the blocking agent (D). Is a low-cost one-pack type heat-crosslinkable resin that has a latent crosslinkable property that has no problem in terms of storage stability by causing a cross-linking reaction under heat treatment conditions at a relatively low temperature of 120 ° C or higher and 180 ° C or lower. It is preferable in that an aqueous polyurethane resin composition can be obtained.

The blocked isocyanate group is added to the side chain and / or
Or as a method of introducing to the molecular terminal, after adjusting the urethane prepolymer having an isocyanate group at the molecular terminal,
There is a method of reacting the above-mentioned blocking agent or first reacting a part of the isocyanate group of the organic polyisocyanate with the blocking agent, and then synthesizing a urethane prepolymer.

The lower limit of the content of blocked isocyanate groups to be introduced into the urethane prepolymer is at least 2% by weight, preferably at least 4% by weight, in terms of regenerated isocyanate groups. Further, the upper limit of the content of the blocked isocyanate group is 18 or less, preferably 15
It is as follows. If the content of the blocked isocyanate group is outside the above lower limit, various properties such as water resistance, adhesion, solvent resistance, and heat resistance cannot be improved, which is not preferable. Further, when the content of the blocked isocyanate group is outside the above upper limit, the formed film becomes very brittle and deteriorates in flexibility, and the film forming property is reduced, and water resistance, adhesion, and solvent resistance are reduced. , Heat resistance and the like are undesirably lowered.

The carboxyl group in the urethane prepolymer is introduced to cause emulsification / dispersion in water by the salt-forming agent as described above. However, in order to perform sufficient emulsification / dispersion, , The acid value of the carboxyl group is 1
The range of 0 mgKOH / g to 60 mgKOH / g is preferable from the viewpoint of improving emulsification / dispersion in water by a salt forming agent and adhesion to various synthetic fibers. In particular,
When an epoxy cross-linking agent is used in combination, heat resistance,
Various properties such as solvent resistance, water resistance and adhesion are remarkably improved. When the acid value of the carboxyl group is less than 10 mgKOH / g, not only the emulsification / dispersion in water by the salt forming agent becomes poor, but also the adhesiveness to the nonwoven fabric becomes poor, which is not preferable. In addition, the acid value of the carboxyl group is 60 mg
If it exceeds KOH / g, the salt-forming agent is excellent in emulsification / dispersion in water and adhesion to a nonwoven fabric, but it is not preferable because it has poor water resistance.

Various methods for emulsifying and dispersing the urethane prepolymer in the present invention are conceivable. First, a compound (A) having two or more active hydrogen atoms, a carboxyl group-containing compound (B) having at least two or more hydroxyl groups, an organic polyisocyanate (C), and a blocking agent (D) The urethane prepolymer having a blocked isocyanate group at the side chain and / or the molecular terminal obtained by the reaction of the above is reacted with water using the above-mentioned salt-forming agent with respect to the carboxyl group introduced by the carboxyl group-containing compound (B). There is a method of obtaining an anionic water-based polyurethane resin by emulsifying and dispersing in water. Secondly, there is a method of emulsifying and dispersing the urethane prepolymer in water, and then increasing the molecular weight by reaction with a polyamine or water to obtain an anionic aqueous polyurethane resin. In the present invention, the polyurethane resin (E) is produced by emulsifying and dispersing the urethane prepolymer in water as described above.

As the above-mentioned polyamine, hydrazine,
Examples include polyamino compounds such as ethylenediamine, propylenediamine, hexylenediamine, isophoronediamine, xylylenediamine, piperazine, diphenylmethanediamine, ethyltolylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, and tetraethylenepentamine.

The preferred lower limit of the weight average molecular weight of the polyurethane resin (E) in the water-crosslinkable water-based polyurethane resin composition of the present invention is 1,500 or more, and 2,000 or more.
More preferably, it is the above. The preferred upper limit of the weight average molecular weight is 5,000 or less, more preferably 4,000 or less. Polyurethane resin (E)
If the weight-average molecular weight of the compound falls outside the above lower limit, a sufficient film-forming ability cannot be secured, which is not preferable. On the other hand, if the weight average molecular weight is outside the above upper limit, the thermal crosslinking effect is reduced, and properties such as heat resistance, solvent resistance, chemical resistance, and water resistance are undesirably reduced.

In the heat-crosslinkable water-based polyurethane resin composition of the present invention, (A), (B) or (C) in 1,000 atomic weight of the polyurethane resin (E).
The total number of the aromatic ring groups and the aliphatic ring groups represented by the structural formula 3 or 4 introduced from is preferably 2 or more, and more preferably 2.5 or more. .
When the total number of the aromatic ring groups and the aliphatic ring groups is less than the above, the effect of improving heat resistance, solvent resistance, chemical resistance, water resistance, and the like due to the high cohesive force of these groups is preferably reduced. Absent.

The heat-crosslinkable water-based polyurethane resin composition of the present invention can further improve various properties such as heat resistance, solvent resistance, and water resistance, although addition of an epoxy-based cross-linking agent limits the pot life. Can be improved. The epoxy-based cross-linking agent to be added has an average of at least 2 glycidyl groups in the molecule, preferably 2.5 or more. If the number of glycidyl groups is less than the above, the effect as a cross-linking agent is small, and the effects of improving various properties such as adhesion, solvent resistance, heat resistance and water resistance are not recognized, which is not preferable. Epoxy equivalent of epoxy crosslinking agent to be added (WP
A preferred lower limit of E) is 110 or more, and more preferably 140 or more. The preferred upper limit of the epoxy equivalent is 300 or less, and more preferably 200 or less. If the range of the epoxy equivalent is smaller than the above lower limit, the effect as a crosslinking agent cannot be obtained, and the effects of improving various properties such as adhesion, solvent resistance, heat resistance, and water resistance cannot be recognized, which is not preferable. Also, when the range of the epoxy equivalent is larger than the above upper limit, the effect as a cross-linking agent is not obtained, and the effects of improving various properties such as adhesion, solvent resistance, heat resistance, and water resistance are not recognized, which is not preferable.

Further, the water solubility of the epoxy crosslinking agent to be added is 20% or more, preferably 50% or more. When the water solubility is lower than these values, uniform dispersion cannot be achieved when blended with the heat-crosslinkable water-based polyurethane resin composition, and the effects of improving various properties such as adhesion, solvent resistance, heat resistance, and water resistance cannot be recognized. Not preferred.

Here, the water solubility of the epoxy crosslinking agent is 2
When 10 parts by weight of an epoxy crosslinking agent is added to and dissolved in 90 parts by weight of water at 0 ° C., the percentage of the dissolved epoxy crosslinking agent with respect to the added epoxy crosslinking agent is referred to.

When the epoxy-based crosslinking agent is added, the mixing ratio is polyurethane resin (E): epoxy-based crosslinking agent = 100: 50-100: 5, preferably 100: 40-100, in terms of solids weight ratio. : 10 range. If the mixing ratio of the epoxy-based crosslinking agent is out of the above range, the effect as a crosslinking agent cannot be obtained, and the adhesion, solvent resistance, heat resistance,
The effect of improving various properties such as water resistance is not recognized, which is not preferable.

Specific examples of the epoxy crosslinking agent as described above include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol. And diglycidyl ether.

The heat-crosslinkable water-based polyurethane resin composition of the present invention has a toxicity which was a problem in a carboxyl group-containing water-based polyurethane resin containing a conventional melamine-based, epoxy-based, aziridine-based, carbodiimide-based, oxazolidine-based crosslinker, etc. It is a one-pack type aqueous polyurethane resin composition without the above problems and storage stability, and with latent crosslinking properties, with low solvent volatility and non-flammability,
Excellent paint workability.

The heat-crosslinkable water-based polyurethane resin composition of the present invention has excellent adhesion to various synthetic fibers such as vinylon, polyester, nylon, rayon, etc., and has excellent solvent resistance,
Because it is excellent in various performances such as heat resistance and water resistance,
It is useful as a non-woven fabric reinforcing agent, and more specifically, filters such as air filters and liquid filters, automotive interior materials such as floor mats, vehicle materials such as various filters for automobiles, abrasives, felts for papermaking, electric wire retainers. tape,
Industrial materials such as battery separators, anti-suction materials, water-blocking materials, roofing, dew-forming sheets and other civil engineering and building materials, etc.
It can be applied to various fields.

The water-crosslinkable water-based polyurethane resin composition of the present invention and the nonwoven fabric reinforcing agent containing the composition can be used by various processing methods. For example, various processing methods such as a spray method, an immersion treatment method, and a roller coater method can be mentioned. For the purpose of improving processing workability, general thickeners, leveling agents, defoaming agents, film forming aids, etc. It is also possible to mix various additives such as the above within a range that does not lower the performance, in order to obtain properties suitable for the purpose.

In addition to the epoxy cross-linking agent, there are toxicity problems and limitations on the usable time. However, a melamine-based, aziridine-based, carbodiimide-based, oxazolidine-based cross-linking agent, etc. is blended to further improve the performance. It is also possible to aim.

The present invention is not limited to a reinforcing agent for various nonwoven fabrics,
It can also be used as a binder for paper requiring various properties such as solvent resistance, heat resistance and water resistance.

[0047]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Synthesis Example 1 Bisphenol A alkylene derivative (bisphenol A ethylene oxide 4 mol adduct, average molecular weight 4) in methyl ethyl ketone solvent
00) 100 parts of polymeric MDI (average molecular weight 3
60, the number of functional groups 2.7) (270 parts) and dimethylolpropionic acid (33.5 parts) were added, and the mixture was reacted at a system temperature of 75 ° C to obtain an isocyanate group-containing urethane prepolymer. Next, 88 parts of methyl ethyl ketoxime was added at a system temperature of 55 ° C. to carry out a blocking reaction to obtain a blocked isocyanate group-containing urethane prepolymer in terms of regenerated NCO groups of 10.5% by weight (acid value 28. 5). The urethane prepolymer is treated with an aqueous solution of sodium hydroxide (NaOH).
After emulsifying with 8 parts of water in 1150 parts of water), the methyl ethyl ketone solvent was distilled off under reduced pressure, and a thermally crosslinkable water-based polyurethane resin (weight average molecular weight: 2,000, number of aromatic ring groups per 1,000 atomic weight: 5.1) ) Got.

(Synthesis Example 2) In a methyl ethyl ketone solvent, 100 parts of a polyester polyol (a polyester polyol composed of 1.6 hexanediol and adipic acid and isophthalic acid, average molecular weight 1700) was added to polymeric MDI (average molecular weight 360, average number of functional groups 2). .7) 63.
5 parts and 7.9 parts of dimethylolpropionic acid were added and reacted at a system temperature of 75 ° C. to obtain an isocyanate group-containing urethane prepolymer. Next, 20.5 parts of methyl ethyl ketoxime was added at a system temperature of 55 ° C., and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer in terms of regenerated isocyanate groups of 5.8% by weight (acid value). 17.2). The urethane prepolymer was treated with an aqueous solution of sodium hydroxide (2.3 parts of NaOH and 350 parts of water).
The resulting mixture was emulsified with a water-soluble polyurethane resin (weight average molecular weight of 3440, the total number of aliphatic ring groups and aromatic ring groups in 1,000 atomic weight of 3440). .6).

Synthesis Example 3 Polypropylene glycol (average molecular weight 1100) in a methyl ethyl ketone solvent
100 parts of polymeric MDI (average molecular weight 360,
2.7) 98 parts of functional groups, dimethylolpropionic acid 1
After adding 2.2 parts, the reaction was carried out at a system temperature of 75 ° C. to obtain an isocyanate group-containing urethane prepolymer (acid value 21.1). Next, 32 parts of methyl ethyl ketoxime was added at a temperature of 55 ° C. in the system, and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 7.3% by weight in terms of regenerated isocyanate groups. The urethane prepolymer is treated with an aqueous solution of sodium hydroxide (NaOH).
After emulsifying with 3.5 parts of water in 550 parts of water), the methyl ethyl ketone solvent was distilled off under reduced pressure, and a thermally crosslinkable aqueous polyurethane resin (weight average molecular weight 2760, number of aromatic ring groups in 1000 atomic weight 3. 0).

(Synthesis Example 4) Polypropylene glycol (average molecular weight 1100) in a methyl ethyl ketone solvent
100 parts of polymeric MDI (average molecular weight 360,
2.7) 98 parts of functional groups, dimethylolpropionic acid 1
After adding 2.2 parts, the reaction was carried out at a system temperature of 75 ° C to obtain an isocyanate group-containing urethane prepolymer. Next, 55 parts of ortho-secondary butylphenol was added at a system temperature of 75 ° C., and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 7.3% by weight in terms of regenerated isocyanate groups. (Acid value 19.
2) The urethane prepolymer was emulsified with a sodium hydroxide aqueous solution (3.5 parts of NaOH dissolved in 500 parts of water), and then the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain a heat-crosslinkable aqueous polyurethane resin (weight average molecular weight 302).
2.8 aromatic ring groups in 0 or 1000 atomic weight, provided that
(Without the aromatic ring of the blocking agent).

Synthesis Example 5 Bisphenol A alkylene derivative (bisphenol A ethylene oxide 4 mol adduct, average molecular weight 4) in methyl ethyl ketone solvent
00) 100 parts of hexamethylene diisocyanate
(Average molecular weight: 168.2, number of functional groups: 2) 98.1 parts, trimethylolpropane 11.2 parts, dimethylolpropionic acid 11.2 parts were added, and the reaction was carried out at a temperature of 75 ° C. in the system to contain an isocyanate group. A urethane prepolymer was obtained. Next, 21.2 parts of methyl ethyl ketoxime was added at a temperature of 55 ° C. in the system, and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 4.6% by weight in terms of regenerated isocyanate groups (acid value). 19.
4). After emulsifying the urethane prepolymer with an aqueous solution of sodium hydroxide (3.2 parts of NaOH dissolved in 450 parts of water), the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain a thermally crosslinkable aqueous polyurethane resin (weight average molecular weight 302
(Aromatic ring group number: 2.1 in 0, 1000 atom weight) was obtained.

(Synthesis Example 6) 100 parts of polyester polyol (a polyester polyol composed of 1.6 hexanediol and adipic acid and isophthalic acid, average molecular weight 1700), 9 parts of 1.4 butanediol, 9 parts of trimethylolpropane in a methyl ethyl ketone solvent 80 parts of tolylene diisocyanate was added to 8 parts, and the system temperature was 75 ° C.
After performing a reaction for 60 minutes under the following conditions, 12 parts of dimethylolpropionic acid and polyethylene glycol (average molecular weight of 60
0) 16 parts of an amine catalyst were added and the reaction was carried out at a system temperature of 75 ° C. to obtain an isocyanate group-containing urethane prepolymer. Next, 16 parts of methyl ethyl ketoxime was added at a temperature of 55 ° C. in the system, and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 3.5% by weight in terms of regenerated isocyanate groups (acid value 20.
8). To the urethane prepolymer, 7.2 parts of triethylamine was mixed and emulsified in 450 parts of water. Then, 2.9 parts of a chain extender triethylenetetramine (equivalent to 1.5% by weight in terms of regenerated isocyanate groups) was added. The reaction was allowed to proceed, and the methyl ethyl ketone solvent was distilled off under reduced pressure.
Thus, a total number of the aliphatic ring groups and the aromatic ring groups in the 00 atomic weight of 2.8, that is, 2.0% by weight in terms of regenerated isocyanate groups (containing blocked isocyanate groups) was obtained.

(Comparative Synthesis Example 1) Polypropylene glycol (molecular weight 1100) 1 in a methyl ethyl ketone solvent
To 00 parts, 65.5 parts of polymeric MDI (molecular weight: 360, number of functional groups: 2.7) were added, and the mixture was reacted at a temperature of 75 ° C. in the system, and 7.8% by weight of free isocyanate groups (polypropylene glycol, polymeric MDI) A urethane prepolymer containing (based on the total amount) was obtained. Next, 19 parts of methyl ethyl ketoxime was added at a system temperature of 55 ° C. to perform a blocking reaction. Next, 67 parts of a 20% aqueous solution of sodium taurate was added at a temperature of 50 ° C. in the system, and emulsified in 400 parts of water. Then, the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain a heat-crosslinkable aqueous polyurethane resin ( Weight average molecular weight 2250, 2.5 aromatic ring groups in 1000 atomic weight, 5.5% by weight in terms of regenerated isocyanate groups
Containing a blocked isocyanate group).

(Comparative Synthesis Example 2) Tolylene diisocyanate (average molecular weight 174.2, functional group 2) was added to 100 parts of a bisphenol A alkylene derivative (bisphenol A ethylene oxide 4 mol adduct, average molecular weight 400) in methyl ethyl ketone solvent. ) 131 parts and dimethylolpropionic acid 33.5 parts were added, and the system temperature was 75 ° C.
The reaction was performed under the following conditions to obtain an isocyanate group-containing urethane prepolymer. Next, 43 parts of methyl ethyl ketoxime was added at a temperature of 55 ° C. in the system, and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 7.8% by weight in terms of regenerated isocyanate groups (acid value 45. 6). After emulsifying the urethane prepolymer with an aqueous solution of sodium hydroxide (6 parts of NaOH dissolved in 550 parts of water), the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain a heat-crosslinkable aqueous polyurethane resin (weight average molecular weight of 125
(Aromatic ring group number 6.1 in 0, 1000 atom weight) was obtained.

(Comparative Synthesis Example 3) In a methyl ethyl ketone solvent, 100 parts of a polyester polyol (a polyester polyol composed of 1.6 hexanediol and adipic acid and isophthalic acid, average molecular weight 1700), 16 parts of 1.4 butanediol, and trimethylol To 1.5 parts of propane, 69 parts of tolylene diisocyanate was added and reacted at a temperature of 75 ° C. in the system. Then, 11 parts of dimethylolpropionic acid and polyethylene glycol (average molecular weight: 60
0) 15 parts of an amine catalyst were added, and the reaction was carried out at a system temperature of 75 ° C to obtain an isocyanate group-containing urethane prepolymer. Next, 1.8 parts of methyl ethyl ketoxime was added at a system temperature of 55 ° C., and a blocking reaction was carried out to obtain a blocked isocyanate group-containing urethane prepolymer of 0.4% by weight in terms of regenerated isocyanate groups (acid value). 2
1.5). The urethane prepolymer was mixed with 8.3 parts of triethylamine and emulsified in 550 parts of water, and then the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain a heat-crosslinkable aqueous polyurethane resin (weight average molecular weight 22,000, 10
(Total number of aliphatic ring groups and aromatic ring groups in 2,000 atomic weight: 2.8) was obtained.

(Comparative Synthesis Example 4) In a methyl ethyl ketone solvent, 100 parts of a polyester polyol (a polyester polyol composed of 1.6 hexanediol and adipic acid and isophthalic acid, average molecular weight of 1700) was added to polymeric MDI (average molecular weight: 360, number of functional groups) 2.7) 6
3.5 parts and 7.9 parts of dimethylolpropionic acid were added and reacted at a system temperature of 75 ° C. to obtain an isocyanate group-containing urethane prepolymer (acid value 19.3). The urethane prepolymer is treated with an aqueous solution of sodium hydroxide (NaO)
H2.5 parts were dissolved in 320 parts of water), and after the chain was extended with the emulsified water, the methyl ethyl ketone solvent was distilled off under reduced pressure to obtain an aqueous polyurethane resin (weight average molecular weight of 31,000, at 1000 atomic weight). (Total number of aliphatic ring groups and aromatic ring groups: 4.0; regenerated isocyanate groups: 0%).

<Method of Measuring Weight-Average Molecular Weight> The weight-average molecular weight of the urethane prepolymer obtained in each synthesis was measured from the relative molecular weight based on polystyrene by gel filtration chromatography. In addition, in the synthesis example 6, the comparative synthesis example 3, and the comparative synthesis example 4, although there was a tetrohydrofuran insoluble matter, the measurement was performed after extraction with a membrane filter.

GPC measurement conditions: Column used: Tosoh TSK-GEL G-1000H _XL x 2 TSK-GEL G-2000H _XL x 1 TSK-GEL G-3000H _XL x 1 TSK-GEL G-4000H _XL x One detection method; RI detector (SHIMADZU SPD-6A) Carrier; Tetrohydrofuran (Examples 1 to 6) Each of the thermally crosslinkable water-based polyurethane resin compositions obtained in Synthesis Examples 1 to 6 was Teflon (registered trademark). It is applied on a plate with a bar coater so as to be 500 μm in a dry state, dried at room temperature for 24 hours, and then dried at 150 ° C. for 30 hours.
A partial heat treatment was performed to form a polyurethane resin film. The physical properties of the obtained polyurethane resin film were compared.
In addition, each of the water-crosslinkable aqueous polythermal urethane resins obtained in Synthesis Examples 1 to 6 was applied on an untreated polyester film using a bar coater so as to have a dry film thickness of 10 μm, and was heated at 150 ° C. For 5 minutes. The test pieces were used to compare the adhesion to the polyester film. Further, after diluting each of the thermally crosslinkable aqueous polyurethane resin compositions obtained in Synthesis Examples 1 to 6 with water so as to have a solid content of 15%, impregnated in a polyester nonwoven fabric,
After passing through a mangle squeezing machine (a squeezing pressure of 2 kg / cm ² ), it was forcibly dried in an atmosphere at 150 ° C. for 3 minutes to prepare a nonwoven fabric processed with a reinforcing agent. The abrasion resistance and elastic modulus of the reinforcing agent-treated nonwoven fabric were compared. The results are shown in Table 1.

Example 7 The heat-crosslinkable water-based polyurethane resin obtained in Synthesis Example 1 was mixed with sorbitol polyglycidyl ether (four glycidyl groups, epoxy equivalent 180, water solubility 94%) as an epoxy cross-linking agent. 1 by weight
Compounded at a ratio of 00:15, an epoxy-crosslinked polyurethane film was prepared under the same method and conditions as in Examples 1 to 6, and various physical properties were compared. In addition, using the epoxy combined water-based polyurethane resin obtained by blending the above epoxy crosslinking agent in the above blending ratio, a polyester film test piece was prepared under the same method and conditions as in Examples 1 to 6, and the test piece was used. The adhesion to the polyester film was compared. Also,
Using a water-based polyurethane resin combined with epoxy obtained by blending the epoxy crosslinking agent at the above blending ratio, a reinforcing agent-treated polyester nonwoven fabric was prepared under the same method and conditions as in Examples 1 to 6, and the reinforcing agent-treated nonwoven fabric was used. The abrasion resistance and the modulus of elasticity were compared. The results are shown in Table 1.

Example 8 The heat-crosslinkable aqueous polyurethane resin obtained in Synthesis Example 4 was combined with sorbitol polyglycidyl ether (4 glycidyl groups, epoxy equivalent 180, water solubility 94%) as an epoxy crosslinking agent on a solid basis. 1 by weight
Compounded at a ratio of 00:15, an epoxy-crosslinked polyurethane film was prepared under the same method and conditions as in Examples 1 to 6, and various physical properties were compared. Further, a polyester film test piece was prepared in the same manner and under the same conditions as in Examples 1 to 6 using an epoxy-containing water-based polyurethane resin obtained by blending the above epoxy crosslinking agent in the above blending ratio, and the test piece was used as a polyester. The adhesion to the film was compared. In addition, Examples 1 to 4 were performed using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent in the blending ratio described above.
A reinforcing agent-treated polyester nonwoven fabric was prepared under the same method and conditions as in Example 6, and the abrasion resistance and elastic modulus of the reinforcing agent-treated nonwoven fabric were compared. The results are shown in Table 1.

Example 9 The thermally crosslinkable water-based polyurethane resin obtained in Synthesis Example 6 was mixed with sorbitol polyglycidyl ether (4 glycidyl groups, epoxy equivalent 180, water solubility 94%) as an epoxy crosslinker. 1 by weight
Compounded at a ratio of 00:15, an epoxy-crosslinked polyurethane film was prepared under the same method and conditions as in Examples 1 to 6, and various physical properties were compared. Further, using an epoxy-based water-based polyurethane resin obtained by blending the epoxy crosslinking agent in the above blending ratio, a polyester film test piece was prepared under the same method and conditions as in Examples 1 to 6, and the test piece was used. The adhesion to the polyester film was compared. In addition, a reinforcing agent-processed polyester nonwoven fabric was prepared in the same manner and under the same conditions as in Examples 1 to 6 using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent in the above blending ratio, and using the reinforcing agent. The abrasion resistance and elastic modulus of the processed nonwoven fabric were compared. The results are shown in Table 1. Example 10 Glycerol polyglycidyl ether (three glycidyl groups, epoxy equivalent 140, water solubility 99%) as an epoxy crosslinking agent was added to the heat-crosslinkable aqueous polyurethane resin obtained in Synthesis Example 6 in terms of solid content weight ratio. 100: 15
And an epoxy cross-linked polyurethane film was prepared under the same method and conditions as in Examples 1 to 6, and various physical properties were compared. Further, using an epoxy-based water-based polyurethane resin obtained by blending the epoxy crosslinking agent in the above blending ratio, a polyester film test piece was prepared under the same method and conditions as in Examples 1 to 6, and the test piece was used. The adhesion to the polyester film was compared. In addition, a reinforcing agent-processed polyester nonwoven fabric was prepared in the same manner and under the same conditions as in Examples 1 to 6, using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent at the above blending ratio, and using the reinforcing agent. The abrasion resistance and elastic modulus of the processed nonwoven fabric were compared. The results are shown in Table 1.

Example 11 The heat-crosslinkable aqueous polyurethane resin obtained in Synthesis Example 6 was added to lauryl alcohol glycidyl ether (glycidyl group 1) as an epoxy crosslinking agent.
(Equipment: 952, epoxy equivalent: 100%, water content: 100%) were mixed in a ratio of 100: 15 in terms of solids weight ratio, and an epoxy crosslinked polyurethane film was prepared in the same manner and under the same conditions as in Examples 1 to 6 to compare various physical properties. Was done. Further, using an epoxy-based water-based polyurethane resin obtained by blending the epoxy crosslinking agent in the above blending ratio, a polyester film test piece was prepared under the same method and conditions as in Examples 1 to 6, and the test piece was used. The adhesion with the polyester film was compared. Further, a reinforcing agent-processed polyester non-woven fabric was prepared under the same method and conditions as in Examples 1 to 6, using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent at the above blending ratio, and using the reinforcing agent. The abrasion resistance and elastic modulus of the processed nonwoven fabric were compared. The results are also shown in Table 2.

(Example 12) Glycol diglycidyl ether (two glycidyl groups, epoxy equivalent 112, water solubility 100%) as an epoxy crosslinking agent was added to the heat-crosslinkable aqueous polyurethane resin obtained in Synthesis Example 6 to obtain a solid content. 1 by weight
Compounded at a ratio of 00:15, an epoxy-crosslinked polyurethane film was prepared under the same method and conditions as in Examples 1 to 6, and various physical properties were compared. Further, a polyester film test piece was prepared in the same manner and under the same conditions as in Examples 1 to 6 using an epoxy-containing water-based polyurethane resin obtained by blending the above epoxy crosslinking agent at the above blend ratio, and the test piece was used. The adhesion with the polyester film was compared. Further, a reinforcing agent-processed polyester non-woven fabric was prepared under the same method and conditions as in Examples 1 to 6, using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent at the above blending ratio, and using the reinforcing agent. The abrasion resistance and elastic modulus of the processed nonwoven fabric were compared. The results are also shown in Table 2.

(Comparative Examples 1 to 3) Polyurethane films were prepared using the various heat-crosslinkable aqueous polyurethane resins obtained in Comparative Synthesis Examples 1 to 3 in the same manner and under the same conditions as in Examples 1 to 6. Various physical properties were compared. In addition, Comparative Synthesis Examples 1 to 3
A polyester film test piece was prepared in the same manner and under the same conditions as in Examples 1 to 6 using the various heat-crosslinkable water-based polyurethane resins obtained in the above, and the adhesion between the test piece and the polyester film was compared. In addition, Comparative Synthesis Examples 1 to 3
Using a variety of thermally crosslinkable aqueous polyurethane resins obtained in the above, a reinforcing agent-treated polyester nonwoven fabric was prepared in the same manner and under the same conditions as in Examples 1 to 6, and the abrasion resistance and elastic modulus of the reinforcing agent-treated nonwoven fabric were compared. did. The results are also shown in Table 2.

Comparative Example 4 Using the aqueous polyurethane resin obtained in Comparative Synthesis Example 4, a polyurethane film was formed in the same manner and under the same conditions as in Examples 1 to 6, and various physical properties were compared. Further, a polyester film test piece was prepared using the aqueous polyurethane resin obtained in Comparative Synthesis Example 4 in the same manner and under the same conditions as in Examples 1 to 6, and the adhesion between the test piece and the polyester film was compared. Further, a reinforcing agent-treated polyester nonwoven fabric was prepared using the aqueous polyurethane resin obtained in Comparative Synthesis Example 4 in the same manner and under the same conditions as in Examples 1 to 6, and the wear resistance and elastic modulus of the reinforcing agent-treated nonwoven fabric were measured. Compared. The results are also shown in Table 2.

Comparative Example 5 The thermally crosslinkable aqueous polythermal urethane resin obtained in Synthesis Example 6 was added to the epoxy crosslinker sorbitol polyglycidyl ether (four glycidyl groups,
(Epoxy equivalent: 180, water solubility: 94%) were mixed in a ratio of 100: 60 in terms of solids weight ratio, and an epoxy cross-linked polyurethane film was prepared in the same manner and under the same conditions as in Examples 1 to 6, and various physical properties were compared. Was. Further, a polyester film test piece was prepared in the same manner and under the same conditions as in Examples 1 to 6 using an epoxy-containing water-based polyurethane resin obtained by blending the above epoxy crosslinking agent at the above blend ratio, and the test piece was used. The adhesion with the polyester film was compared. Further, a reinforcing agent-processed polyester non-woven fabric was prepared under the same method and conditions as in Examples 1 to 6, using an epoxy-containing water-based polyurethane resin obtained by blending the epoxy crosslinking agent at the above blending ratio, and using the reinforcing agent. The abrasion resistance and elastic modulus of the processed nonwoven fabric were compared. The results are also shown in Table 2.

(Comparative Example 6) Using commercially available polyvinyl alcohol, a film was formed in the same manner and under the same conditions as in Examples 1 to 6, and various physical properties were compared. Further, polyester film test pieces were prepared using polyvinyl alcohol under the same method and conditions as in Examples 1 to 6, and the adhesion between the test pieces and the polyester film was compared. Further, a reinforcing agent-treated polyester nonwoven fabric was prepared using polyvinyl alcohol under the same method and conditions as in Examples 1 to 6, and the abrasion resistance and elastic modulus of the reinforcing agent-treated nonwoven fabric were compared. The results are also shown in Table 2.

<Performance evaluation method> (1) Evaluation of Water Resistance of Film The polyurethane film was cut into 4 × 2 cm, immersed in warm water at 40 ° C. for 24 hours, and the area increase rate immediately after being taken out was measured. The value of the initial area is set to 0%. (2) Evaluation of solvent resistance of the film The polyurethane film was cut into 4 x 2 cm pieces, and ethyl acetate /
The area increase rate immediately after being immersed in toluene = 100/100 (weight ratio) for 24 hours and taken out is measured. The value of the initial area is set to 0%. (3) Evaluation of film strength and elongation A polyurethane film cut to a width of 5 mm was measured by a tensile tester (test speed 200 mm / min). (4) Evaluation of heat resistance of film The heat melting point of the film is measured using a melting point analyzer (MICRO MELTING POINT AP).
PARATUS, manufactured by YANACO). (5) Evaluation of Adhesion The polyester film test piece obtained by the method shown in each example was subjected to a cross-cut test of cellotape (registered trademark) peeling in accordance with JIS-K5400, and evaluated by counting the number of remaining cross-cuts. . (6) Evaluation of abrasion resistance of nonwoven fabric processed with a reinforcing agent A-80 sandpaper was attached to an arm (200 g) of a friction fastness tester, and fluffing of the nonwoven fabric was visually evaluated by reciprocating 100 times. The evaluation criteria were ◎ for those with little fluffing, ○ for those with little fluffing, and x) for those with much fluffing. (7) Evaluation of abrasion resistance of nonwoven fabric processed with reinforcing agent Dynamic viscoelasticity tester [Relograph Toyo Seiki Co., Ltd.]
The elastic modulus was measured at a heating rate of 5 ° C./min, and the elastic modulus at the time of reaching 150 ° C. was evaluated.

[0070]

[Table 1]

[0071]

[Table 2]

<Evaluation Results> As shown in Tables 1 and 2, good results were obtained in each performance test by the nonwoven fabric reinforcing agents of Examples 1 to 12, and particularly, an epoxy-based crosslinking agent was added. It can be seen that the effect of improving various performances can be obtained in this case. In contrast, in the nonwoven fabric reinforcing agents of Comparative Examples 1 to 6,
In each of the tests, the results were inferior to those of the examples.

[0073]

As described above, the water-crosslinkable water-based polyurethane resin composition of the present invention contains at least 2% by weight of blocked isocyanate groups in terms of regenerated isocyanate groups in a medium to high molecular weight polyurethane resin skeleton. Since it contains a polyurethane resin (E), a sufficient film forming ability is ensured, and a heat treatment causes a cross-linking reaction between the polyurethane resin and the adherend, resulting in water resistance, adhesion, and solvent resistance. Properties such as heat resistance and heat resistance can be remarkably improved.

The crosslinkable water-based polyurethane resin of the present invention exhibits excellent properties such as excellent solvent resistance, adhesion, heat resistance and water resistance by crosslinking as described above.
It is excellent in adhesion to various synthetic fibers, particularly polyester fibers, and is useful as a nonwoven fabric reinforcing agent capable of satisfying all the above-mentioned various properties.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J034 BA05 CA03 CA04 CA05 CA22 CB03 CB04 CB05 CB07 CB08 CC03 CC12 CC26 CC45 CC61 CC62 CC67 CD04 CD06 CD09 CD14 DA01 DA05 DB03 DB07 DF01 DF02 DF12 DF14 DG06 DG27 DM12 DN01 DP33 EA HA01 HA07 HC03 HC12 HC13 HC17 HC22 HC46 HC52 HC61 HC64 HC67 HC71 HC73 HD03 HD04 HD05 HD07 HD12 HD15 JA41 LA07 QA05 QA07 QC05 RA09 4L033 AB07 CA52

Claims (6)

[Claims] 1. A compound (A) having two or more active hydrogen atoms, a carboxyl group-containing compound (B) having at least two hydroxyl groups, an organic polyisocyanate (C), and a blocking agent (D) A weight-average molecular weight of 1,500 obtained by dispersing a urethane prepolymer containing 2% by weight or more and 18% by weight or less in terms of regenerated isocyanate groups in a molecule obtained by the reaction with A thermally crosslinkable water-based polyurethane resin composition containing not less than 50,000 and not more than 50,000 polyurethane resins (E). 2. The polyurethane resin (E) of 1,00
The total number of aromatic ring groups and aliphatic ring groups represented by the following structural formula 1 or 2 introduced from (A), (B) or (C) in 0 atomic weight is 2 or more The water-crosslinkable water-based polyurethane resin composition according to claim 1, wherein Embedded image Embedded image 3. The thermally crosslinkable composition according to claim 1, wherein the organic polyisocyanate (C) is an aromatic isocyanate, and the blocking agent (D) is an oxime blocking agent. Water-based polyurethane resin composition. 4. The urethane prepolymer has an acid value of a carboxyl group of 10 mg KOH / g to 60 mg KO.
The heat-crosslinkable water-based polyurethane resin composition according to any one of claims 1 to 3, wherein the composition is in the range of H / g. 5. A compound having at least two glycidyl groups on average in the molecule, having an epoxy equivalent of 110 to 300,
An epoxy-based crosslinking agent having a water solubility of 20% or more is blended in a weight ratio of solid content of the polyurethane resin (E): the epoxy-based crosslinking agent = 100: 50 to 100: 5. The thermally crosslinkable water-based polyurethane resin composition according to any one of claims 1 to 4. 6. A nonwoven fabric reinforcing agent comprising the heat-crosslinkable water-based polyurethane resin composition according to claim 1.