JP7099074B2 - Method for manufacturing urethane resin composition - Google Patents

Description

The present invention relates to a method for producing a urethane resin composition.

Urethane resin has the characteristics of toughness and flexibility, so it is used in various fields such as synthetic leather, films, adhesives, adhesives, coating agents, vehicle interior materials, moisture permeable clothing, molded products, polishing pads, shoes, and furniture. Widely used.

As the urethane resin, it is widely used to use an amine-based chain extender as a raw material and to impart toughness by introducing a urea bond (see, for example, Patent Document 1). On the other hand, in recent years, due to the trend of solvent regulation in Europe and China, it is required to reduce the amount of N, N-dimethylformamide (DMF), which is most frequently used as a solvent. Under such circumstances, the use of a ketone solvent having excellent solubility in urethane resin has been studied, but there is a problem that yellowing is likely to occur.

Japanese Unexamined Patent Publication No. 2016-27114

An object to be solved by the present invention is to provide a method for producing a urethane resin composition having excellent yellowing resistance.

The present invention is a method for producing a urethane resin composition containing a urethane resin (A) having a urea bond and an organic solvent (B), wherein the organic solvent (B) is a ketone solvent (b1) and others. It contains the solvent (b2) of the above, and provides a method for producing a urethane resin composition, which comprises adding the ketone solvent (b1) after forming a urea bond.

The urethane resin composition obtained by the production method of the present invention is excellent in yellowing resistance. Moreover, since the amount of DMF used can be reduced, it is possible to contribute to the reduction of the environmental load.

Therefore, the urethane resin composition obtained by the production method of the present invention is used in the fields of synthetic leather, films, adhesives, adhesives, coating agents, vehicle interior materials, moisture permeable clothing, molded products, polishing pads, shoes, furniture and the like. Can be suitably used in.

The urethane resin composition obtained in the present invention contains a urethane resin (A) having a urea bond and an organic solvent (B), and the organic solvent (B) is a ketone solvent (b1) and others. It contains the solvent (b2) of. Further, in the method for producing a urethane resin composition of the present invention, it is essential to add the ketone solvent (b1) after forming a urea bond. By this method, not only excellent yellow denaturation resistance but also bleeding substances can be suppressed, and a film having a good tactile sensation can be obtained.

The urethane resin (A) has a urea bond, and examples thereof include reactants using at least a polyol (a1), a polyisocyanate (a2), and a compound (a3) having an amino group as raw materials.

As the polyol (a1), for example, a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyacrylic polyol, a polybutadiene polyol, a hydrogenated polybutadiene polyol, or the like can be used. These polyols may be used alone or in combination of two or more.

The number average molecular weight of the polyol (a1) is preferably in the range of 500 to 50,000 and more preferably in the range of 600 to 10,000 from the viewpoint of obtaining even more excellent mechanical strength of the film. , 700-8,000 is more preferred. The number average molecular weight of the polyol (a1) indicates a value measured by a gel permeation chromatography (GPC) method.

The amount of the polyol (a1) used is preferably in the range of 30 to 95% by mass, more preferably in the range of 50 to 90% by mass in the raw material constituting the urethane resin (A).

Examples of the polyisocyanate (a2) include 1,3- and 1,4-phenylenedi isocyanate, 1-methyl-2,4-phenylenedi isocyanate, 1-methyl-2,6-phenylenediisocyanate, 1-methyl-2. , 5-Hexamethylene diisocyanate, 1-methyl-2,6-phenylenediisocyanate, 1-methyl-3,5-phenylenediisocyanate, 1-ethyl-2,4-phenylenediisocyanate, 1-isopropyl-2,4-phenylenediisocyanate, 1,3-dimethyl-2,4-phenylenediisocyanis, 1,3-dimethyl-4,6-phenylenediisocyanate, 1,4-dimethyl-2,5-phenylenediisocyanis, diethylbenzenediisocyanate, diisopropylbenzenediisocyanis, 1-methyl- 3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1, 5-Diisocyanate, 1-methyl-naphthalen-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4 '-Diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4- Aromatic polyisocyanis such as diisocyanate; tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3- Cyclohexamethylene diisocyanate, 1,4-cyclohexamethylene diisocyanate, 1,3-di (isocyanismethyl) cyclohexane, 1,4-di (isocyanisammethyl) cyclohexane, lysine diisocyanis, isophoron diisocyanate, 4,4-dicyclohexammethane diisisethylene, 2, 4'-Dicyclohexamethylene diisocyanate, 2,2'-dicyclohexamethylene diisoci Aliphatic or alicyclic polyisocyanates such as anate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate and the like can be used. These polyisocyanates may be used alone or in combination of two or more.

The amount of the polyisocyanate (a2) used is preferably in the range of 3 to 50% by mass, more preferably in the range of 10 to 40% by mass in the raw material constituting the urethane resin (A).

The compound (a3) having an amino group introduces a urea bond into the urethane resin (A), and examples thereof include those having a molecular weight of less than 500 (preferably in the range of 50 to 450). , Ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazin, 2,5-dimethylpiperazine, isophoronediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4- Cyclohexanediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, hydrazine and the like can be used. These compounds may be used alone or in combination of two or more.

The amount of the compound (a3) used is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 1 to 20% by mass in the raw materials constituting the urethane resin (A).

As the raw material of the urethane resin (A), in addition to the above, for example, a chain extender having a hydroxyl group having a molecular weight of less than 500, a compound having a hydroxyl group and a (meth) acryloyl group, a silicone compound having a hydroxyl group, or the like is used. May be.

Examples of the chain extender having a hydroxyl group having a molecular weight of less than 500 include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. Hexamethylene glycol, saccharose, methylene glycol, trimethylolpropane, glycerin, sorbitol, bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, hydrogenated bisphenol A, Hydroquinone or the like can be used. These compounds may be used alone or in combination of two or more.

Examples of the compound having a hydroxyl group and a (meth) acryloyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth) acrylate, and 4 -Hydroxybutyl (meth) acrylate, 6-hydroxyhexyl acrylate, hydroxyethyl acrylamide, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like can be used. These compounds may be used alone or in combination of two or more.

The organic solvent (B) contains a ketone solvent (b1) and another solvent (b2).

As the ketone solvent (b1), for example, methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, heptanone, isophorone and the like can be used. These solvents may be used alone or in combination of two or more. Among these, one or more solvents selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, acetone, and cyclohexanone are used from the viewpoint of obtaining even more excellent solubility and drying property in the urethane resin (A). Is preferable.

Examples of the other solvent (b2) include N, N-dimethylformamide, N, N-dimethylacetamide, tetrahydrofuran, tetrahydropyran, dimethylsulfoxide, N-methylpyrrolidone, N, N, 2-trimethylpropionamide. , N, N-dimethylacrylamide, N, N-dimethylpropionamide, N, N-diethylacetamide, N, N-diethylacrylamide, 1,3-dimethyl-2-imidazolidinone, N-ethylpyrrolidone, 3-methoxy -N, N-dimethylpropanamide, methanol, ethanol, n-propanol, isopropanol, ethylene glycol, diethylene glycol, propylene glycol and the like can be used. These solvents may be used alone or in combination of two or more. Among these, it is preferable to contain N, N-dimethylformamide from the viewpoint of solubility, but any solvent may be used as long as it has good solubility in the urethane resin (A).

Next, a method for producing the urethane resin composition of the present invention will be described.

In the method for producing a urethane resin composition of the present invention, it is essential to add the ketone solvent (b1) after the urea bond is formed. By this method, not only excellent yellow denaturation resistance but also bleeding substances can be suppressed, and a film having a good tactile sensation can be obtained.

Specific examples of the method for producing the urethane resin composition include, for example,
(1) In the presence of the other solvent (b2), at least the polyisocyanate (a2) and the compound (a3) are reacted to form a urea bond, and then the ketone solvent (b1) is added. After that, a method for forming a urethane bond derived from the polyol (a1);
(2) In the presence of the other solvent (b2), the polyol (a1) and the polyisocyanate (a2) are reacted to form a urethane bond, and then the compound (a3) is reacted. Examples thereof include a method of forming a urea bond and then adding the ketone solvent (b1).

In the method (1), the polyol (a1) may be charged into the reaction system from the beginning together with the compound (a3) or the like, or may be charged after forming a urea bond. Even if the polyol (a1) is first charged together with the compound (a3) or the like, the amino group of the compound (a3) reacts much faster with the isocyanate group than the hydroxyl group of the polyol (a1). Therefore, urea bonds are preferentially generated.

Examples of the conditions for forming the urea bond include a method of reacting at a temperature of 15 to 50 ° C. for 10 minutes to 3 hours.

After the urea bond is formed, the ketone solvent (b1) can be added to cope with the thickening (higher molecular weight of the urethane resin) at the time of the subsequent urethane bond formation. When the ketone solvent (b1) is added, it is preferable that the temperature in the reaction system is equal to or lower than the boiling point of the ketone solvent (b1).

Examples of the conditions for forming the urethane bond include a method of reacting at a temperature of 55 to 120 ° C. for 30 minutes to 10 hours.

When forming the urethane bond, a known urethanization catalyst may be used, if necessary. Examples of the amount used when the urethanization catalyst is used include a range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A).

Also in the method (2), the conditions for forming the urea bond and the urethane bond are the same as those in the method (1).

The urea bond content of the urethane resin (A) is preferably in the range of 0.15 to 0.45 mmol / kg, preferably 0.2 to 0, from the viewpoint of obtaining even more excellent yellowing resistance. A range of .4 mmol / kg is more preferred.

The urethane resin (A) can be increased in molecular weight by the above method, and the weight average molecular weight thereof may be, for example, in the range of 3,000 to 150,000. The weight average molecular weight of the urethane resin (A) indicates a value measured by a gel permeation chromatography (GPC) method.

The content of the organic solvent (B) is preferably in the range of 40 to 80% by mass in the urethane resin composition from the viewpoint of coatability, drying property, and production stability.

The content of the ketone solvent (b1) is preferably 25% by mass or more in the organic solvent (B), preferably 50 to 75, from the viewpoint of obtaining even more excellent drying property and yellowing resistance. The mass% range is more preferred.

As described above, the urethane resin composition obtained by the production method of the present invention is excellent in yellowing resistance. In addition, since the amount of DMF used can be reduced, it can also contribute to environmental friendliness.

Therefore, the urethane resin composition obtained by the production method of the present invention is used in the fields of synthetic leather, films, adhesives, adhesives, coating agents, vehicle interior materials, moisture permeable clothing, molded products, polishing pads, shoes, furniture and the like. Can be suitably used in.

Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
125 parts by mass of a polycarbonate polyol (number average molecular weight; 2,000) made from 1,6-hexanediol in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. 230 parts by mass of N, N-dimethylformamide (hereinafter abbreviated as "DMF") and 25 parts by mass of 4,4'-dicyclohexylmethanediisocyanate (hereinafter abbreviated as "H12MDI") are added and stirred. After reacting at 85 ° C. for 4 hours, the inside of the reaction system was cooled to 30 ° C., then 4.8 parts by mass of isophoronediamine (hereinafter abbreviated as “IPDA”) was added, and the mixture was stirred for 30 minutes. Next, 0.2 parts by mass of methanol was added, and then 230 parts by mass of methyl ethyl ketone (hereinafter abbreviated as “MEK”) was added, and the mixture was stirred and mixed to obtain a urethane resin composition. The urea bond content of the urethane resin was 0.365 mmol / kg.

[Example 2]
125 parts by mass of a polycarbonate polyol (number average molecular weight; 2,000) made from 1,6-hexanediol in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. 230 parts by mass of DMF and 4.8 parts by mass of IPDA were added, and after uniformly mixing, 25 parts by mass of H12MDI was added. After stirring for 30 minutes, 230 parts by mass of MEK was added and reacted at 75 ° C. for 4 hours under stirring to obtain a urethane resin composition. The urea bond content of the urethane resin was 0.365 mmol / kg.

[Comparative Example 1]
125 parts by mass of a polycarbonate polyol (number average molecular weight; 2,000) made from 1,6-hexanediol in a four-necked flask equipped with a thermometer, agitator, an inert gas inlet, and a reflux condenser. 230 parts by mass of DMF and 25 parts by mass of H12MDI were added and reacted at 85 ° C. for 4 hours under stirring, then 230 parts by mass of MEK and 4.8 parts by mass of IPDA were added, and the mixture was stirred for 30 minutes. Then, 0.2 part by mass of methanol was added and stirred for 10 minutes to obtain a urethane resin composition.

[Comparative Example 2]
125 parts by mass of a polycarbonate polyol (number average molecular weight; 2,000) made from 1,6-hexanediol in a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. 230 parts by mass of MEK and 4.8 parts by mass of IPDA were added, and after uniform mixing, 25 parts by mass of H12MDI was added. After stirring for 30 minutes, 230 parts by mass of DMF was added and reacted at 75 ° C. for 4 hours under stirring to obtain a urethane resin composition.

[Measurement method for number average molecular weight, etc.]
The number average molecular weight of the polyol and the weight average molecular weight of the urethane resin show the values obtained by measuring under the following conditions by the gel permeation column chromatography (GPC) method.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (Differential Refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[Evaluation method for yellowing resistance]
The urethane resin compositions obtained in Examples and Comparative Examples were left for 500 hours at a high temperature of 120 ° C. using a fade meter "U48" manufactured by Suga Test Instruments Co., Ltd. It was evaluated as.
"○": No yellowing is confirmed.
"X": Yellowing is confirmed.

[Evaluation method of bleed resistance]
The urethane resin compositions obtained in Examples and Comparative Examples were applied onto a release paper so that the film thickness after drying was 30 μm, and dried at 90 ° C. for 2 minutes and further at 120 ° C. for 2 minutes. , A polyurethane film was obtained. After the polyurethane film was left at 100 ° C. for 2 weeks, the bleed resistance of the polyurethane film was evaluated as follows by visual observation.
"○": No bleeding is confirmed.
"X": A bleeding object is confirmed.

[Evaluation method of tactile sensation]
The polyurethane film obtained by the above [method for evaluating bleed resistance] was left at 100 ° C. for 2 weeks, and then the tactile sensation was evaluated by a tactile finger as follows.
"○": Soft.
"×": I feel hardness in some places.

In Examples 1 to 6, which are the production methods of the present invention, urethane resin compositions capable of forming a film having excellent yellow resistance, bleed resistance, and tactile sensation were obtained.

On the other hand, in Comparative Examples 1 and 2, a ketone solvent and a compound having an amino group were added at the same time to generate a urea bond in the presence of the ketone solvent, but both of them had poor yellow denaturation resistance. In addition, bleeding substances were also confirmed, and the tactile sensation was poor.

Claims (6)

A method for producing a urethane resin composition containing a urethane resin (A) having a urea bond and an organic solvent (B).
The urea bond content of the urethane resin (A) is in the range of 0.15 to 0.45 mmol / kg.
The content of the organic solvent (B) is in the range of 40 to 80% by mass in the urethane resin composition.
The organic solvent (B) contains a ketone solvent (b1) and another solvent (b2), and is characterized by adding the ketone solvent (b1) after forming a urea bond. A method for producing a resin composition. The method for producing a urethane resin composition according to claim 1, wherein the urethane resin (A) is made from at least a polyol (a1), a polyisocyanate (a2), and a compound (a3) having an amino group. Claim 2 to add the ketone solvent (b1) after reacting at least the polyisocyanate (a2) and the compound (a3) to form a urea bond in the presence of the other solvent (b2). The method for producing a urethane resin composition according to the above method. In the presence of the other solvent (b2), the polyol (a1) and the polyisocyanate (a2) are reacted to form a urethane bond, and then the compound (a3) is reacted to form a urea bond. The method for producing a urethane resin composition according to claim 2, wherein the urethane resin composition is produced and then the ketone solvent (b1) is added. The method for producing a urethane resin composition according to any one of claims 1 to 4 , wherein the content of the ketone solvent (b1) is 25% by mass or more in the organic solvent (B). The method for producing a urethane resin composition according to any one of claims 1 to 5 , wherein the ketone solvent (b1) is at least one selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, acetone, and cyclohexanone.