JPH1149875A - Production of moisture-permeable film excellent in film strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a moisture-permeable film improved in moisture permeability and film strength in good balance, suitable as a moisture-permeable film for a moisture-permeable water-proof fabric and capable of being widely utilized in uses such as sports wearers, cold-proof wearers, working wearers, etc. SOLUTION: This method for producing a moisture-permeable film comprises coating a resin solution comprising a fluorine-modified polyurethane and a water-insoluble, solvent-soluble polyalkylene oxide modified product in a weight ratio of 55/45 to 95/5 on a mold release paper with a comma coater in a uniform thickness, drying the coated solution and subsequently peeling the release paper. When the moisture-permeable film is integrally laminated by a transfer method, excellent moisture permeability and excellent film strength can efficiently and easily be imparted to a moisture-permeable, waterproof fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a moisture-permeable film having a good balance between moisture permeability and film strength, and more particularly as a moisture-permeable waterproof fabric for sports clothing, winter clothing, work clothes and the like. Can be widely used.

[0002]

2. Description of the Related Art Hitherto, as a moisture-permeable waterproof cloth, a method of applying a water-miscible solvent solution of polyurethane onto a fiber cloth and then immersing it in a water bath to form a microporous membrane (Japanese Patent Publication No. 60-47955). And a method of forming a porous resin layer made of a synthetic polymer mainly composed of fluorine-modified polyurethane on a fiber cloth (Japanese Patent Application Laid-Open No. 3-27184). However, since these moisture-permeable waterproof fabrics have a hydrophobic microporous membrane structure by a wet coagulation method, the membrane strength is low, and, for example, sweat as water vapor during light exercise can be permeated, but liquid sweat during intense exercise does not. There was a drawback that it was not released and was accompanied by independence.

Further, a method of blending a hydrophilic substance into a resin film for the purpose of releasing liquid sweat (Japanese Patent Publication No. 5-4407) has been attempted, but the film strength is extremely high when moisture or water is absorbed. And the moisture permeability was insufficient.

[0004]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to improve the above-mentioned drawbacks. As a result, dry film formation is carried out from a resin solution containing a fluorine-modified polyurethane and a water-insoluble, solvent-soluble polyalkylene oxide-modified product. Thus, it has been found that a moisture-permeable film having improved moisture permeability and film strength in a well-balanced manner can be easily obtained, and is suitable as a moisture-permeable film for a moisture-permeable waterproof fabric.

[0005]

The first object of the present invention is to provide a method for producing a moisture-permeable film having excellent film strength, comprising 55 to 95% by weight of a fluorine-modified polyurethane and a water-insoluble, solvent-soluble polyalkylene oxide-modified product. It is characterized by dry film formation from a resin solution containing 45% by weight.

[0006] A second aspect of the present invention is a method for producing a moisture-permeable film having excellent film strength, wherein 55 to 95% by weight of a fluorine-modified polyurethane and 5 to 45% by weight of a water-insoluble, solvent-soluble modified polyalkylene oxide are formed on a fiber cloth. % By dry film formation from a resin solution containing 0.1% by weight.

The fluorine-modified polyurethane of the present invention can be obtained by a method of copolymerizing a polyurethane and a fluorine-containing polymer by a polymer reaction or a method of copolymerizing a fluorine-containing compound having at least one active hydrogen with the polyurethane ( JP-A-4-146275, JP-A-4-163
373 and JP-A-6-2278). By imparting hydrophobicity by fluorine modification of polyurethane, water-insoluble hydrophilic polymer,
The phase separation from the solvent-soluble polyalkylene oxide modified product is promoted, and the moisture permeability and the film strength are further improved. Usually, the fluorine content is preferably 10 to 50%.

[0008] Water-insoluble and solvent-soluble modified polyalkylene oxides include polyethylene oxide, polypropylene oxide, mixtures thereof and copolymers.
For example, those obtained by a crosslinking treatment using an isocyanate compound (JP-A-50-36280 and JP-A-6-36280)
-316623). By blending the polyalkylene oxide, the moisture permeability is remarkably improved, and liquid sweat can be released. Further, by making water insoluble by the crosslinking treatment, it is possible to suppress a decrease in film strength in a state of absorbing moisture or absorbing water.

The mixing ratio of the fluorine-modified polyurethane and the water-insoluble and solvent-soluble polyalkylene oxide-modified product is 55/45 to 95/5% by weight, preferably 60/40 to 50/40, which has a good balance between moisture permeability and membrane strength. 70/30% by weight. When the compounding ratio of the fluorine-modified polyurethane is 5
If it is less than 5% by weight, the moisture permeability is improved, but the film strength is significantly reduced. When the content exceeds 95% by weight, the film strength is improved, but the moisture permeability is remarkably reduced, and all of them are not practical.

As a solvent in the dry film formation, dimethylformamide, dimethylacetamide, tetrahydrofuran, dimethylsulfoxide and the like alone or a mixture thereof are usually used. Dry film formation is performed by casting the resin solution and evaporating the solvent.However, preferably, the resin solution is applied on a release paper to a uniform thickness by a comma coater, a knife coater, a reverse coater, etc., and then dried. The film is formed by releasing the release paper. The moisture-permeable film of the present invention has a remarkably improved film strength by dry film formation, and has a thickness of usually 5 to 30 μm.
In consideration of moisture permeability and film strength, the thickness is preferably 10 to 20 μm. In the resin film, a coloring agent, a stabilizer, a filler,
Other additives may be added.

The fiber fabric used in the present invention is a woven fabric, a knitted fabric, a nonwoven fabric, or the like made of a single fiber of nylon, polyester, polyacrylonitrile, cotton, rayon, or a mixture of these fibers. Is also good. As a method of forming a resin film on a fiber fabric by dry film formation, a transfer method, a method of directly adhering the resin film to the fiber fabric, a direct gravure coating method and the like are used, and a method by transfer is more preferable. .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluorine-modified polyurethane and a water-insoluble, solvent-soluble polyalkylene oxide-modified product
/ 45-95 / 5% by weight of a dimethylformamide solution is applied on a release paper using a comma coater to a uniform thickness, and then dried at 80 ° C. for 10 minutes to release the release paper, thereby obtaining moisture permeability and film strength. However, it is possible to easily produce a moisture-permeable film having an improved balance. If this moisture-permeable film is laminated and integrated with a fiber fabric, it can be widely used for applications as a moisture-permeable waterproof fabric. The properties of the obtained moisture-permeable film were evaluated according to the following criteria.

(1) The moisture permeability is determined according to JIS L 1099-
It was measured by the 1985 A-1 method. (2) Membrane strength The dry strength was previously cut into strips at 20 ° C and a relative humidity of 6
Conditioning was performed for 24 hours or more in a 5% room, and measurement was performed by an autograph in the room. The wet strength is cut into strips in advance, immersed in distilled water for 24 hours or more,
The measurement was performed by an autograph in a room adjusted to a relative humidity of 65%.

[0014]

Example 1 A resin solution having a resin solid content concentration of 12.5% having the following formulation was applied to a uniform thickness on release paper using a comma coater, and then dried at 80 ° C. for 10 minutes to peel off the release paper. A 10 μm moisture permeable film was obtained. Table 1 shows the evaluation results of the characteristics. Formulation 1 Hydrophobic polymer / Hydrophilic polymer = 7/3 Fluorine-modified polyurethane (21% dimethylformamide solution) (Lackskin UJ-8390, manufactured by Seiko Chemical Co., Ltd.) 100 parts by weight Water-insoluble, solvent-soluble modified polyalkylene oxide ( Crystal melting enthalpy change ΔH = 161.38 J / g) (Aqua Coke T, manufactured by Sumitomo Seika Co., Ltd.) 9 parts by weight Dimethylformamide 131 parts by weight

[0015]

Example 2 In Example 1, a water-insoluble, solvent-soluble polyalkylene oxide modified product having low crystallinity (crystal enthalpy change ΔH = 129.43 J /
g) A moisture-permeable film was obtained in the same manner except that (Aqua Coke TQ-5, manufactured by Sumitomo Seika) was changed. The evaluation results of the characteristics are shown in Table 1. As compared with Example 1, the diffusibility of water vapor was improved, and the moisture permeability was slightly improved.

[0016]

Example 3 A moisture-permeable film was prepared in the same manner as in Example 2, except that the ratio of hydrophobic polymer / hydrophilic polymer was changed to 6/4, and that Aquacork TQ-5 was changed to 14 parts by weight and dimethylformamide to 166 parts by weight. Obtained. The evaluation results of the properties are shown in Table 1. As compared with Examples 1 and 2, the moisture permeability is further improved, but the film strength, particularly, the moisture strength is reduced.

[0017]

Comparative Example 1 A moisture-permeable film was obtained in the same manner as in Example 1, except that Aqua-Coke T was not used. The evaluation results of the properties are shown in Table 1. As compared with Example 1, the film strength was remarkably improved, but on the contrary, the moisture permeability was significantly reduced.

[0018]

Comparative Example 2 In Example 2, the rack skin UJ-8 was used.
A moisture-permeable film was obtained in the same manner except that 390 was not used. The evaluation results of the properties are shown in Table 1. As compared with Examples 1 and 2, the moisture permeability is remarkably improved, but the film strength is remarkably reduced.

[0019]

[Table 1]

[0020]

EFFECTS OF THE INVENTION A water-insoluble, solvent-soluble modified polyalkylene oxide modified with a fluorine-modified polyurethane is 55/45.
By dry-forming a film from a resin solution of about 95/5% by weight, a moisture-permeable film having improved moisture permeability and film strength in a well-balanced manner can be easily produced. This moisture-permeable film is suitable as a moisture-permeable film of a moisture-permeable waterproof fabric, and is widely used in applications such as sports clothing, winter clothing, and work clothing.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 75/04 C08L 75/04 D06M 15/576 D06M 15/576

Claims (2)

[Claims] 1. 55 to 95% by weight of a fluorine-modified polyurethane
A method for producing a moisture-permeable film having excellent film strength, comprising dry-forming a film from a resin solution containing 5 to 45% by weight of a water-insoluble, solvent-soluble modified polyalkylene oxide. 2. A fluorine-modified polyurethane 5 on a fiber cloth.
Forming a resin film by dry film-forming from a resin solution containing 5 to 95% by weight and 5 to 45% by weight of a water-insoluble, solvent-soluble modified polyalkylene oxide; Production method.