JP6946985B2 - Film manufacturing method - Google Patents

Description

The present invention relates to a method for producing a dry film of a urethane resin composition containing a solvent.

Urethane resin has the characteristics of being flexible and tough, and also has an excellent texture, so that it is widely used in the production of synthetic leather, molded products, adhesives, coating agents, and the like. The urethane resin generally takes the form of a resin solution containing N, N-dimethylformamide (hereinafter abbreviated as "DMF"), which has excellent solubility in urethane resin, and this urethane resin solution is used. It has been the mainstream until now to form a urethane resin film by applying it to a base material and drying it (see, for example, Patent Document 1).

However, DMF may cause allergic reactions and dermatitis, and has been taken up as a substance of very high concern (Substance of Very High Concern, hereinafter abbreviated as "SVHC") in Europe, and future usage restrictions have been realized. .. However, since DMF, which has excellent compatibility with urethane resin, has been used as an essential solvent, the replacement is not as advanced as the industry desires.

JP-A-2017-75328

An object to be solved by the present invention is to provide a method for producing a dry film having excellent compatibility with urethane resin, excellent drying property, and excellent mechanical strength without using a substance of very high concern as a solvent.

The present invention is a method for producing a film for drying a urethane resin composition containing a urethane resin (A) and a solvent (B), wherein the solvent (B) has a boiling point other than N, N-dimethylformamide. The temperature is less than 230 ° C., and the difference between the Hansen solubility parameter (A-HSP) of the urethane resin (A) and the Hansen solubility parameter (B-HSP) of the solvent (B) is 3 to 8 (J / cm ^3). ) Provided is a method for producing a film, which is characterized in that the range is ^1/2.

According to the present invention, the dry film obtained is excellent in compatibility with urethane resin and drying property without using a substance of very high concern as a solvent, and the obtained dry film is excellent in mechanical strength. Therefore, the present invention can be particularly suitably used for the production of artificial leather / synthetic leather whose use regulation of DMF will become stricter in the future.

The present invention is a method for producing a film by drying a urethane resin composition containing a urethane resin (A) and a solvent (B), and it is essential that the solvent (B) is specific. It is a requirement of.

In the present invention, the solvent (B) has a boiling point of less than 230 ° C. other than N, N-dimethylformamide which is SVHC, and the Hansen solubility parameter (A-HSP) of the urethane resin (A). It is essential that the difference between the solvent (B) and the Hansen solubility parameter (B-HSP) of the solvent (B) is in the range of ^{3 to} 8 (J / cm 3) ^1/2. By using this specific solvent, a urethane resin composition having excellent compatibility with the urethane resin (A) and excellent drying property can be obtained, and since the solvent does not remain in the dried film, a film having excellent mechanical strength can be obtained. Obtainable.

The boiling point of the solvent (B) is preferably in the range of 50 to 225 ° C., preferably in the range of 70 to 220 ° C., from the viewpoint of further improving the compatibility with the urethane resin (A) and the drying property. More preferred.

The Hansen solubility parameter is based on the idea that two substances having similar intramolecular interactions are easily soluble in each other, and specifically, the solubility introduced by Hildebrand. The parameter is divided into three components, a dispersion term (δD), a polarization term (δP), and a hydrogen bond term (δH), and represented in a three-dimensional space. The dispersion term (δD) indicates the effect due to the dispersion force, the polarization term (δP) indicates the effect due to the dipole force, and the hydrogen bond term (δH) indicates the effect due to the hydrogen bond force.

The definition and calculation of the Hansen solubility parameter are described in Charles M. et al. It is described in "Hansen Solubility Parameter; A Users Handbook (CRC Press, 2007)" by Hansen. Further, by using the computer software "Hansen Solubility Parameters in Practice (HSPiP)", the Hansen solubility parameter can be estimated from the chemical structure of a solvent whose parameter value is not described in the literature. In the present invention, the value is used for the solvent whose parameter value is described in the document, and the parameter value estimated by using HSPiP version 4.1.06 is used for the solvent whose parameter value is not described in the document. The Hansen solubility parameter (A-HSP) of the urethane resin (A) indicates a value estimated from the raw materials constituting the urethane resin (A). The difference between the Hansen solubility parameter (A-HSP) of the urethane resin (A) and the Hansen solubility parameter (B-HSP) of the solvent (B) was also calculated according to these.

As the solvent (B), one kind of solvent can be used, or two or more kinds of solvents can be used in combination. When two or more kinds are used in combination, the values obtained by weighted averaging the three parameters of the Hansen solubility parameter of each solvent can be used in a combination within the above range.

As the solvent (B), the dispersion term (δD) in the Hansen solubility parameter is 15. is preferably in the range of 5~21MPa ^0.5, range of 16～20MPa ^0.5 is more preferable. Further, as the dispersion term ([delta] P), for the same reason, preferably in the range of 7～14.5MPa ^0.5, more preferably in the range of 8~13.5J1 / ^{2MPa 0.5.} Further, the dispersion term (δH) is preferably in the range of 4.5 to 11 MPa ^0.5 , and more preferably in ^{the range of 5 to 10 MPa 0.5 for the same reason.}

Specific examples of the solvent (B) include N, N, 2-trimethylpropionamide (Hansen solubility parameter: 20.14, dispersion term (δD): 16.7, polarization term (δP): 9.2, Hydrogen bond term (δH): 6.5, boiling point: 175 ° C.), N, N-dimethylacrylamide (Hansen solubility parameter: 21.81, dispersion term (δD): 17.3, polarization term (δP): 10. 6. Hydrogen bond term (δH): 8.0, boiling point: 80 ° C.), N, N-dimethylpropionamide (Hansen solubility parameter: 21.28, dispersion term (δD): 16.4, polarization term (δP)) 11.3, hydrogen bond term (δH): 7.5, boiling point: 176 ° C), N, N-diethylacetamide (Hansen solubility parameter: 22.42, dispersion term (δD): 16.8, polarization term ( δP): 11.5, hydrogen bond term (δH): 9.4, boiling point: 165 ° C), N, N-diethylacrylamide (Hansen solubility parameter: 19.65, dispersion term (δD): 16.9, polarization Item (δP): 9.2, Hydrogen bond item (δH): 4.0, Boiling point: 94 ° C.), 1,3-Dimethyl-2-imidazolidinone (Hansen solubility parameter: 22.29, Dispersion item (δD) ): 18.2, Polarization term (δP): 10.0, Hydrogen bond term (δH): 8.1, Boiling point: 108 ° C.), N-ethylpyrrolidone (Hansen solubility parameter: 22.74, Dispersion term (δD) ): 18.0, polarization term (δP): 12.0, hydrogen bond term (δH): 7.0, boiling point: 218 ° C.), 3-methoxy-N, N-dimethylpropanamide (Hansen solubility parameter: 22). .52, dispersion term (δD): 17.2, polarization term (δP): 11.0, hydrogen bond term (δH): 9.5, boiling point: 215 ° C.) and the like.

As the solvent (B), N, N, 2-trimethylpropionamide, N, N-dimethyl, because a dry film having a higher mechanical strength can be obtained regardless of the type of the urethane resin (A). It is preferable to use one or more selected from the group consisting of acrylamide and 3-methoxy-N, N-dimethylpropanamide.

The content of the solvent (B) is more excellent in compatibility with the urethane resin and drying property, and the obtained dry film has mechanical strength. Therefore, 10 to 90 in the urethane resin composition. The range is preferably in the range of% by mass, and more preferably in the range of 20 to 80% by mass.

As the urethane resin (A) used in the present invention, a reaction product of the polyol (a1) and the polyisocyanate (a2) can be used. The urethane resin (A) preferably does not have a radically polymerizable group such as a (meth) acryloyl group. The reason is that, for example, when a solvent having a radically polymerizable group is selected, it is crosslinked by irradiation with ultraviolet rays or the like and the texture is impaired.

As the polyol (a1), for example, a polyester polyol, a polyether polyol, a polycarbonate 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 100,000, more preferably in the range of 700 to 10,000, from the viewpoint of mechanical properties and flexibility of the film. The number average molecular weight of the polyol (a1) indicates a value measured by a gel permeation chromatography (GPC) method.

A chain extender (ac) having a number average molecular weight of less than 500 can be used in combination with the polyol (a1), if necessary. As the chain extender (ac), for example, a chain extender having a hydroxyl group, a chain extender having an amino group, or the like can be used. These chain extenders (ac) may be used alone or in combination of two or more.

Examples of the chain extender having a hydroxyl group include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and hexamethylene glycol. Aliphatic polyol compounds such as saccharose, methylene glycol, glycerin, and sorbitol; bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, etc. Aromatic polyol compound; water and the like can be used. These chain extenders may be used alone or in combination of two or more.

Examples of the chain extender having an amino group include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazin, 2,5-dimethylpiperazine, isophoronediamine, 4,4. '-Dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, hydrazine, diethylenetriamine, triethylenetetramine, etc. Can be used. These chain extenders may be used alone or in combination of two or more.

Examples of the polyisocyanate (a2) include 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylenediisocyanate, trienediisocyanate, naphthalenediocyanate, xylylene diisocyanate, and tetra. Aromatic polyisocyanates such as methylxylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; alicyclic polyisocyanates such as cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate should be used. Can be done. These polyisocyanates may be used alone or in combination of two or more.

As a method for producing the urethane resin (A), for example, a method for producing the urethane resin (A) by charging the polyol (a1), the polyisocyanate (a2) and, if necessary, the chain extender (ac) and reacting them. Can be mentioned. These reactions are preferably carried out at a temperature of 50 to 100 ° C. for approximately 3 to 10 hours. Further, the reaction may be carried out in the solvent (B) described later.

The molar ratio of the total of the hydroxyl group of the polyol (a1) and the hydroxyl group and amino group of the chain extender (ac) to the isocyanate group of the polyisocyanate (a2) [(isocyanate group) / (hydroxyl group and amino). The group)] is preferably in the range of 0.8 to 1.2, and more preferably in the range of 0.9 to 1.1.

The weight average molecular weight of the urethane resin (A) is preferably in the range of 5,000 to 500,000 from the viewpoint of mechanical strength and flexibility of the film, and is preferably in the range of 10,000 to 300,000. More preferably, the range of 30,000 to 150,000 is even more preferable. The weight average molecular weight of the urethane resin (A) indicates a value obtained by measuring in the same manner as the number average molecular weight of the polyol (a1).

The urethane resin composition contains the urethane resin (A) and the solvent (B) as essential components, but may also contain other additives, if necessary.

Examples of the other additives include pigments, flame retardants, plasticizers, softeners, stabilizers, waxes, defoamers, dispersants, penetrants, surfactants, fillers, fungicides, antibacterial agents, and ultraviolet rays. Absorbents, antioxidants, weather stabilizers, fluorescent whitening agents, antioxidants, thickeners and the like can be used. These additives may be used alone or in combination of two or more.

Next, as a method of drying the urethane resin composition to produce a film, for example, a dryer or the like in which the urethane resin composition is coated on a base material and the coated product is adjusted to 80 to 120 ° C. There is a method of using and drying for 3 to 10 minutes.

As the base material to which the urethane resin composition is applied, for example, a base material made of a non-woven fabric, a woven fabric, a knitted fabric; a resin film or the like can be used. Examples of the base material are chemical fibers such as polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, and polylactic acid fiber; cotton, linen, silk, wool, and a blended fiber thereof. Etc. can be used.

Even if the surface of the base material is subjected to antistatic processing, mold release processing, water repellent processing, water absorption processing, antibacterial deodorization processing, antibacterial processing, ultraviolet blocking processing, corona treatment, etc., if necessary. good.

Examples of the method of applying the urethane resin composition to the base material surface include a gravure coater method, a knife coater method, a pipe coater method, and a comma coater method.

The thickness of the coating film made of the urethane resin composition is, for example, in the range of 0.5 to 5 mm.

As described above, according to the present invention, the dry film obtained is excellent in compatibility with urethane resin and dryness without using a substance of very high concern as a solvent, and the obtained dry film is excellent in mechanical strength. Therefore, the present invention can be particularly suitably used for the production of artificial leather / synthetic leather whose use regulation of DMF will become stricter in the future.

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

[Example 1]
In a reactor having a stirrer, a recirculator, and a thermometer, 100 parts by mass of polyester polyol (“CMA-244” manufactured by DIC Co., Ltd., number average molecular weight; 2,000), 8 parts by mass of ethylene glycol, N, N, 250 parts by mass of 2-trimethylpropionamide and 45 parts by mass of 4,4'-diphenylmethane diisocyanate were added and reacted at 85 ° C. with stirring until the viscosity reached 600 dPa · s, and then 0.22 parts by mass of methanol. Was added and reacted to obtain a urethane resin composition containing a urethane resin (A-1).
100 parts by mass of this urethane resin composition was applied onto a paper pattern so that the thickness after drying was 30 μm, and dried at 90 ° C. for 2 minutes and further at 120 ° C. for 2 minutes to obtain a urethane resin film.
The Hansen solubility parameter of the urethane resin (A-1) is 22.12, the dispersion term (δD): 19.0, the polarization term (δP): 7.7, and the hydrogen bond term (δH): 8.3. there were.

[Example 2]
A urethane resin composition and a urethane resin film were obtained in the same manner as in Example 1 except that N, N-dimethylacrylamide was used instead of N, N, 2-trimethylpropionamide.

[Example 3]
A urethane resin composition and a urethane resin film were obtained in the same manner as in Example 1 except that 3-methoxy-N, N-dimethylpropanamide was used instead of N, N, 2-trimethylpropionamide. rice field.

[Example 4]
A urethane resin composition and a urethane resin film were obtained in the same manner as in Example 1 except that N, N-dimethylpropionamide was used instead of N, N, 2-trimethylpropionamide.

[Comparative Example 1]
A urethane resin composition and a urethane resin film were obtained in the same manner as in Example 1 except that γ-butyrolactone was used instead of N, N, 2-trimethylpropionamide.

[Comparative Example 2]
A urethane resin composition and a urethane resin film were obtained in the same manner as in Example 1 except that 2-pyrrolidone was used instead of N, N, 2-trimethylpropionamide.

[Measurement method of number average molecular weight]
The number average molecular weight of the polyol or the like used in the synthesis example shows the value measured under the following conditions by the gel permeation 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 of compatibility with urethane resin (A)]
In Examples and Comparative Examples, the obtained urethane resin composition was divided into glass bottles and evaluated as follows by visual observation.
"T": There is no turbidity and it is transparent.
"F": Turbidity is confirmed.

[Evaluation method of dryness]
The urethane resin films obtained in Examples and Comparative Examples were touched with a finger and evaluated as follows.
"5": No feeling of tackiness.
"3": A feeling of tackiness is felt a little.
"1": The feeling of tack is strong.

[Evaluation method of mechanical strength]
The urethane resin film obtained in Examples and Comparative Examples is cut into strips having a width of 5 mm and a length of 50 mm, and chucked using a tensile tester "Autograph AG-I" (manufactured by Shimadzu Corporation). A tensile test was conducted in an environment with a distance of 40 mm, a tensile speed of 10 mm / sec, and a humidity of 23 ° C., and the stress (MPa) at 100% elongation was measured.

The abbreviations in "Table 1" are as follows.
-"DMIB": N, N, 2-trimethylpropionamide-"DMAA": N, N-dimethylacrylamide- "DMPA": 3-methoxy-N, N-dimethylpropanamide- "DMP": N, N- Dimethylpropionamide ・ "DMSO": dimethyl sulfoxide ・ "GBL": γ-butyrolactone ・ "Pyr": 2-pyrrolidone

It was found that the present invention is excellent in compatibility with urethane resin and drying property without using a substance of very high concern as a solvent, and the obtained dry film is excellent in mechanical strength.

On the other hand, in Comparative Example 1, the difference between the Hansen solubility parameter (A-HSP) of the urethane resin (A) and the Hansen solubility parameter (B-HSP) of the solvent (B) exceeds the range specified in the present invention. However, the compatibility with the urethane resin was poor, the drying property was also poor, and the mechanical strength of the obtained film was also poor.

Comparative Example 2 is an embodiment in which 2-pyrrolidone having a boiling point exceeding the range specified in the present invention is used, but the compatibility with the urethane resin is poor and the drying property is also extremely poor, and the obtained film is mechanical. The strength was also poor.

Claims (1)

A method for producing a film for drying a urethane resin composition containing a urethane resin (A) and a solvent (B).
The solvent (B) is at least one selected from the group consisting of N, N, 2-trimethylpropionamide, N, N-dimethylacrylamide, and 3-methoxy-N, N-dimethylpropanamide. A characteristic film manufacturing method.