JP3633970B2 - Water-based polyurethane resin - Google Patents

Description

【００１８】
【発明の効果】
このように本発明によって従来の水性ポリウレタン樹脂では成し得なかった低温領域でのより柔軟でかつエラスティックな水性ポリウレタン樹脂の提供を可能とした。
【００１９】
【図面の簡単な説明】
【図１】図１に表１の物性値をｓｔｒｅｓｓ−ｓｔｒａｉｎ曲線で示した。[0001]
[Industrial application fields]
The present invention relates to an aqueous polyurethane resin, and more particularly to an aqueous polyurethane resin that is more flexible and elastic in a low temperature region. In the present invention, “aqueous” is a generic term for water dispersibility and water solubility.
[0002]
[Prior art]
In recent years, interest in water-based resins has been increasing in place of conventional organic solvent-based resins from the viewpoints of pollution, environmental pollution, etc. Among them, water-based polyurethane resins are treating agents for artificial leather and fibers because of their excellent mechanical properties. Or, it is used in a wide range of fields as an adhesive.
Conventionally, it is known that an aqueous polyurethane resin using polytetramethylene ether glycol as a polyol component has excellent rubber elasticity with relatively little temperature dependency and is also excellent in hydrolysis resistance.
[0003]
[Problems to be solved by the invention]
However, even in this resin, the film physical properties are confirmed to decrease in elongation and stress as the temperature decreases, and the flexibility is lost, and it is often pointed out that the physical properties change greatly at low temperatures. It had been.
[0004]
[Means for Solving the Problems]
The present inventors have examined water-based polyurethane resins that do not impair the superiority of water-based polyurethanes containing polytetramethylene ether glycol as components and have little change in physical properties at low temperatures, and are improved by the following water-based polyurethane resins. I found out.
[0005]
That is, the present invention relates to a group represented by a —CH ₂ CH (R 1) CH (R 2) CH ₂ O— group (one of R 1 and R 2 is hydrogen and the other is a methyl group). And a random copolymer polyol (A) composed of a group represented by —CH ₂ CH ₂ CH ₂ CH ₂ O— (Chemical Formula 2), wherein the ratio of (Chemical Formula 1) is 5 to 30% by weight; Hydrophilic substance (number average molecular weight 90 to 3000) (B) having at least one carboxyl group and at least two hydroxyl groups, and polyisocyanate compound (C) , isocyanate equivalent of component (C) / (A) Component + (B) component hydroxyl equivalent ratio 1 . 1-2 . 5 reaction, the carboxyl group in the molecule is 0 . 2-2 . Saturated urethane urethane prepolymer introduced in the range of 0% by weight is placed in an aqueous solution in which a compound having ionicity opposite to the carboxyl group is dissolved, and a hydrophilic salt is formed by a neutralization reaction, which is stable in water. This is a polyurethane water dispersion obtained by mechanically dispersing and a method for producing the polyurethane water dispersion described above.
[0006]
The polyol compound that is the component (A) constituting the aqueous polyurethane resin used in the present invention is —CH ₂ CH (R ₁ ) CH (R ₂ ) CH ₂ O— (R ₁ , R ₂ is either hydrogen. The other is a methyl group) and a group represented by —CH ₂ CH ₂ CH ₂ CH ₂ O— (Chemical 2), and these structural units The polymerization mode is random copolymerization.
Such a polyol (A) is, for example, a strong acid capable of ring-opening THF, such as a mixture of tetrahydrofuran (hereinafter referred to as THF) and 3-methyltetrahydrofuran in a molar ratio of 85/15 to 20/80, such as chlorosulfonic acid or fluorosulfonic acid. , A random copolymerized polyether dihydroxy compound obtained by copolymerization with perchloric acid at a temperature of usually 0 ° C. to 50 ° C.
The molecular weight that can be used for the polyether A is 600 to 5000, preferably 1500 to 3500.
When the molecular weight of the polyether A is smaller than 600, the obtained aqueous polyurethane resin becomes a resin having poor rubber elasticity, and when the molecular weight is larger than 5,000, the viscosity is greatly increased during the urethanization reaction, and workability is remarkably deteriorated.
The —CH ₂ CH (R ₁ ) CH (R ₂ ) CH ₂ O— group represented by (Chemical Formula ₁ ) is a group given by 3-methyltetrahydrofuran (hereinafter 3 methyl THF) and is used in the present invention for the polyol (A) 5 to 30% by weight is contained.
[0007]
The hydrophilicity-imparting substance (B) having at least one carboxyl group (group for emulsifying the resulting polyurethane compound) and at least two hydroxyl groups used in the present invention is, for example, 2,2-dimethylolpropionic acid, Trifunctional polyols obtained by addition polymerization of monomers such as ethylene oxide, propylene oxide, butylene oxide and styrene oxide as initiators and cyclic acid anhydrides such as isophthalic acid and maleic acid have a molar ratio of 1: 1. And a half-ester compound (number average molecular weight of 90 to 3000) having at least one carboxyl group and at least two hydroxyl groups in the molecule obtained by addition reaction by ring opening.
[0008]
The polyisocyanate compound (C) used in the present invention is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-'diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diene. Isocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3,5-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dimethyl-3,3'-diphenyl diisocyanate, 1,5-naphthalene Known isocyanates such as diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate and the like, and a system in which two or more of these are mixed may be used.
[0009]
In the aqueous polyurethane resin according to the present invention, first, the polyol (A) and the polyisocyanate compound (C) are reacted in the range of isocyanate equivalent (C) / hydroxyl equivalent ratio (A) of 1.0 to 4.7. To produce a chain-terminated isocyanate urethane prepolymer, which is then chain-extended by the reaction of at least one carboxyl group as component (B) and a hydrophilicity-imparting substance having at least two hydroxyl groups, Constituting a prepolymer of both end-isocyanates into which groups have been introduced, the proportion of which is (C) isocyanate equivalent weight / (A) + (B) hydroxyl equivalent ratio in the range of 1.1 to 2.5 and It is prepared so that the carboxyl group content in the prepolymer is in the range of 0.2 to 2.0% by weight. If the isocyanate equivalent ratio of (C) / (A) + (B) hydroxyl equivalent ratio is less than 1.1, the heat resistance will be poor, and if it exceeds 2.5, the heat meltability will be poor and the purpose cannot be achieved. Further, when the hydrophilic group content in the prepolymer is less than 0.2, the hydrophilicity is poor and emulsification does not occur, and when it exceeds 2.0, the water resistance is remarkably deteriorated.
[0010]
In the case of the one-shoulder method, the carboxyl group is reacted in the molecule by reacting the isocyanate equivalent of (C) / (polyol of component (A) + hydroxyl of component (B)) equivalent ratio of 1.1 to 2.5. It constitutes the introduced both-end isocyanate urethane prepolymer.
[0011]
These urethanization reactions can be produced either in the presence or absence of organic solvents, and also in the presence or absence of small amounts of reaction catalysts such as organotins and tertiary amines. It is.
[0012]
The urethane prepolymer introduced with the carboxyl group thus obtained is placed in an aqueous solution in which a compound having an ionicity opposite to that of the carboxyl group such as an alkali metal, alkaline earth metal or organic base is dissolved, and is neutralized by a neutralization reaction. An aqueous polyurethane resin is produced by forming a functional salt and stably dispersing it in water as a high molecular weight product. Tertiary and quaternary amine compounds can be used as the organic base here. Examples of the carboxylate group generated at that time include —COOH, —COONa, —COONH _{4 and the} like.
[0013]
【Example】
Examples will be described in more detail below.
A group represented by —CH ₂ CH (R ₁ ) CH (R ₂ ) CH ₂ O— (where R ₁ and R ₂ are as defined above), and —CH ₂ CH ₂ CH ₂ CH ₂ O—. The polyol (A) composed of a group is abbreviated as PTG-L.
PTG-L2000: manufactured by Hodogaya Chemical Co., Ltd., average molecular weight of 2000, containing 15% by weight of —CH ₂ CH (R ₁ ) CH (R ₂ ) CH ₂ O— group Coronate T-80: manufactured by Nippon Polyurethane Co., Ltd. 2 Tolylene diisocyanate having an isomeric pair of 4, 2 and 6 of 8: 2 [Example 1]
A four-necked flask equipped with a thermometer, a stirrer, and a cooling tube with a drying tube was charged with 396 parts by weight of PTG-L2000 having a hydroxyl value of 56.1, 70 parts by weight of Coronate T-80, and a temperature of 85 in the system. The reaction was carried out at 3.5 ° C. for 3.5 hours to obtain a urethane prepolymer containing 3.68% by weight of active isocyanate. Thereafter, while maintaining the temperature at 85 ° C., 35 parts by weight of a half ester compound having a hydroxyl value of 215.6 obtained from an equimolar reaction of a hydroxyl group having a hydroxyl value of 402.8 and maleic anhydride was added, and reacted for 4 hours. A urethane prepolymer of a molecularly terminal isocyanate in which a carboxyl group was introduced into the molecule containing .31% by weight was obtained.
400 parts by weight of the urethane prepolymer thus obtained was forcibly dispersed for 5 minutes in water at a temperature of 40 ° C. in which 2 parts by weight of sodium hydroxide was dissolved in 357 parts by weight of water, and then rotated at a speed of 300 rpm. The mixture was transferred to a container equipped with stirring blades, and a chain extension reaction was performed for 1 hour while maintaining the temperature at 70 ° C. This reaction is a decarboxylation reaction in which the isocyanate at the molecular end reacts with water.
The polyurethane water dispersion thus obtained had an solid content of 53%, a hydrogen ion index (PH) of 7.1, and an emulsion having a viscosity of 600 cps / 20 ° C. and excellent dispersion stability.
[0014]
[Comparative Example 1]
A four-necked flask equipped with a thermometer, a stirrer, and a cooling tube with a drying tube was charged with 396 parts by weight of PTG2000 having a hydroxyl value of 56.1, and 70 parts by weight of Coronate T-80 was added. And a urethane prepolymer containing 3.68% by weight of active isocyanate was obtained by reacting for 3.5 hours. Thereafter, 35 parts by weight of a half ester compound having a hydroxyl value of 215.6 obtained from an equimolar reaction of a triol having a hydroxyl value of 402.8 and maleic anhydride was added while maintaining the temperature at 85 ° C., and the reaction was carried out for 4 hours. A urethane prepolymer of molecular end-isocyanate having a carboxyl group introduced into the molecule containing 31% by weight was obtained.
400 parts by weight of the urethane prepolymer thus obtained was forcibly dispersed for 5 minutes in water at a temperature of 40 ° C. in which 2 parts by weight of sodium hydroxide was dissolved in 357 parts by weight of water, and then rotated at a speed of 300 rpm. The mixture was transferred to a container equipped with stirring blades, and a chain extension reaction was performed for 1 hour while maintaining the temperature at 70 ° C. This reaction is a decarboxylation reaction in which the isocyanate at the molecular end reacts with water.
The polyurethane water dispersion thus obtained had an solid content of 53%, a hydrogen ion index (PH) of 7.1, and a viscosity of 690 cps / 20 ° C. with excellent dispersion stability.
[0015]
The aqueous polyurethane emulsion obtained in the test example and comparative example of the test body, B-20 (manufactured by Hodogaya Chemical Co., Ltd., water resistance improver) and water were blended at a ratio of 100: 1: 99 and stirred for several minutes. . Then, 45 g of the blended solution is poured into a 20 cm × 30 cm × 0.2 cm glass mold fixed horizontally in advance, and is naturally dried for 48 hours in a constant temperature room at 20 ° C., and a film having a thickness of 0.15 ± 0.05 mm Got. Next, the film was removed from the glass mold, dried in an oven at 110 ° C. for 2 hours, and then punched with a No. 3 dumbbell. Thereafter, it was dried in an oven at 105 ° C. for 1 hour and released in a desiccator to obtain a test specimen.
[0016]
Tensile strength The specimen obtained as described above was left in a thermostat for a tensile tester set at 20 ° C. and −20 ° C. for 15 minutes, and then a tensile test was performed at a set temperature. The tensile test was performed according to JIS K6301 using an orientec universal tensile tester (Tensilon / UTM-III).
The results are shown in Table 1 and FIG.
[0017]
[Table 1]

[0018]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a more flexible and elastic water-based polyurethane resin in a low temperature region, which could not be achieved with a conventional water-based polyurethane resin.
[0019]
[Brief description of the drawings]
FIG. 1 shows physical property values shown in Table 1 as stress-strain curves.

Claims (4)

_{-CH 2 CH (R1) CH (} R2) CH 2 O- group (R1, R2 and the other on either the hydrogen is a methyl group.) A base (Formula 1) represented by, -CH ₂ A random copolymer polyol (A) composed of a group represented by CH ₂ CH ₂ CH ₂ O— (chemical formula 2), wherein the ratio of (chemical formula 1) is 5 to 30% by weight, and trimethylolpropane or glycerin. Ring opening of trifunctional polyols obtained by addition polymerization of monomers selected from ethylene oxide, propylene oxide, butylene oxide and styrene oxide as initiators and cyclic acid anhydrides selected from isophthalic acid and maleic acid at a molar ratio of 1: 1. A compound having at least one carboxyl group and at least two hydroxyl groups in the molecule, or 2,2-dimethylol Hydrophilic property imparting substance (number average molecular weight 90-3000) (B) composed of on acid and polyisocyanate compound (C), (C) component isocyanate equivalent / (A) component + (B) component hydroxyl equivalent ratio It is made to react in the range of 1.1-2.5, and it is set as the both-ends isocyanate urethane prepolymer by which the carboxyl group was introduce | transduced in the range of 0.2-2.0 weight% in the molecule | numerator, and ionicity opposite to a carboxyl group A polyurethane water dispersion obtained by placing in a water solution in which a compound having a salt is dissolved, forming a hydrophilic salt by a neutralization reaction, and stably dispersing in water. The polyurethane water dispersion according to claim 1, wherein the polyol (A) has a molecular weight of 600 to 5,000. _{-CH 2 CH (R1) CH (} R2) CH 2 O- group (R1, R2 and the other on either the hydrogen is a methyl group.) A base (Formula 1) represented by, -CH ₂ A random copolymer polyol (A) composed of a group represented by CH ₂ CH ₂ CH ₂ O— (chemical formula 2), wherein the ratio of (chemical formula 1) is 5 to 30% by weight, and trimethylolpropane or glycerin. Ring opening of trifunctional polyols obtained by addition polymerization of monomers selected from ethylene oxide, propylene oxide, butylene oxide and styrene oxide as initiators and cyclic acid anhydrides selected from isophthalic acid and maleic acid at a molar ratio of 1: 1. A compound having at least one carboxyl group and at least two hydroxyl groups in the molecule, or 2,2-dimethylol Hydrophilic property imparting substance (number average molecular weight 90-3000) (B) composed of on acid and polyisocyanate compound (C), (C) component isocyanate equivalent / (A) component + (B) component hydroxyl equivalent ratio It is made to react in the range of 1.1-2.5, and it is set as the both-ends isocyanate urethane prepolymer by which the carboxyl group was introduce | transduced in the range of 0.2-2.0 weight% in the molecule | numerator, and ionicity opposite to a carboxyl group A method for producing a polyurethane water dispersion, wherein the compound is placed in an aqueous solution in which a compound having a salt is dissolved, a hydrophilic salt is formed by a neutralization reaction, and is stably dispersed in water. The method for producing a polyurethane water dispersion according to claim 3, wherein the polyol of the component (A) has a molecular weight of 600 to 5,000.

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