JPS6047954B2 - Coating fabric and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a durable coated fabric that has both excellent waterproofness and moisture permeability, and a method for producing the same.

Conventionally, waterproof fabrics made of fiber base materials coated with natural rubber or synthetic rubber have been used in waterproof clothing such as rain coats, jets, turbolins, and other products, but all of them have poor moisture permeability, such as rain coats, etc. Waterproof clothing causes discomfort when worn, and water vapor condenses inside the clothing when it is put into practical use.

On the other hand, as a method for imparting air permeability or moisture permeability, there is a so-called wet coagulation method in which a fiber base material is coated or impregnated with a dimethylformamide solution of polyurethane elastomer, and then immersed in an aqueous solution to form a polyurethane porous film. However, although this method can easily impart breathability or moisture permeability, it is difficult to obtain waterproofness.

One way to impart waterproofness to this porous film is to post-treat it with a water repellent, but this method does not allow the water repellent solution to penetrate into the porous film. It is extremely difficult to impart water repellency to the surface of the pores inherent in the film, and as a result, water repellency is imparted only to the surface of the porous film, and although water repellency is obtained, a high degree of water resistance cannot be obtained. There is a drawback that it is insufficiently waterproof. The present inventors improved the above-mentioned drawbacks and studied a method for producing a durable coated fabric that has both waterproofness and moisture permeability, particularly a method for imparting waterproofness to a porous polyurethane film. As a result, by using a polyurethane coating solution prepared by adding predetermined amounts of a water repellent, polyisocyanates, and nonionic surfactants, the inside of a porous polyurethane film produced by a wet coagulation method was used. It is possible to reduce the large diameter of the large number of pores present in the material to fine pores of 5 microns or less, and also to impart water repellency to the surface of the pores, thus providing excellent waterproofness and moisture permeability with durability. The inventors have discovered that the coated fabric can be easily manufactured and have arrived at the present invention. That is, the present invention is a coated fabric having a microporous film made of a synthetic polymer mainly composed of a polyurethane polymer on at least one side of a fiber base material, and the coated fabric has a water resistance of 800? H2O/
Cd or more, 3000 order H2O/d or less, moisture permeability is 2500y/d or more, 2 fences or more, 4800y/d/24
A moisture-permeable and waterproof coated fabric characterized by having a temperature of 11 If or less and a polar organic solvent solution of polyurethane elastomer as a coating liquid, the coating liquid is applied or impregnated onto a fiber base material, and then the fabric is coated in a coagulation bath. In the method of manufacturing a coated fabric by dipping it into a gel, then washing it with water and drying it, the coating liquid is a repellent that is stable at temperatures below 40°C and reacts with polyisocyanates at temperatures above 100°C. Using a polar organic solvent solution having a concentration of 8 to 25% by weight of a polyurethane elastomer containing 1 to 1% by weight of a water agent, 0.2 to 3% by weight of polyisocyanates, and 1 to 8% by weight of a nonionic surfactant, After wet coagulation of the coating liquid, washing with water, and drying,
By applying heat treatment at a temperature of 100°C or higher, the diameter of the micropores inherent in the resulting polyurethane porous film is reduced to 5 microns or less, and the surface of the micropores is imparted with durable water repellency. The present invention provides a method for producing a coated fabric having both excellent waterproofness and moisture permeability as described above.

In the present invention, a specially prepared polar organic solvent solution of polyurethane elastomer is used as the coating liquid. However, as a polar organic solvent, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, etc. can be used, and dimethylformamide is most preferred.

The water repellent to be included in the coating liquid of the present invention is a water repellent that is used at a low temperature, for example, 40°C, relative to the polyisocyanate used in combination.
Any water repellent can be used below as long as it is stable and can react at high temperatures, e.g., 100°C or higher, but fluorine-based water repellents, silicone-based water repellents, or a combination of both may be used. It is particularly effective to use

That is, in the present invention, in order to impart durable water repellency not only to the surface of the polyurethane porous film but also to the surface of the numerous micropores inherent in the film, polyisocyanates may be used together with a water repellent. Although it is required,
If the water repellent used reacts with polyisocyanates at low temperatures, the coating liquid will gel and become unusable.

On the other hand, by using a water repellent that can react at high temperatures,
It can enhance the adhesion between the water repellent agent and the polyurethane porous film (including the surface of the fine pores inherent in the film), and provide excellent and durable water repellency. The content of the water repellent agent must be in the range of 1 to 1% by weight based on the paint liquid; if it is less than 1% by weight, sufficient water repellency will be obtained; If it is more than %, it is not preferable because it tends to make the size of the pores in the porous film formed during wet coagulation non-uniform. Examples of polyisocyanates used in combination with water repellents include compounds having two or more isocyanate groups such as diisocyanates and triisocyanates, such as 2,4-(2,6-)tolylene diisocyanate, diphenylmethane-4, Diisocyanates such as 4''-diisocyanate, 1,4-naphthalene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, etc., and 3 moles of these diisocyanates and 1 mole of a compound having 3 active hydrogens, such as trimethylolpropane, glycerin, etc. Any triisocyanate obtained by the addition reaction of can be used.

Note that these polyisocyanates may be in a form in which isocyanate groups are free or in a form in which phenol or the like is added to stabilize them. In the present invention, the purpose of containing polyisocyanates in the coating liquid is to increase the adhesion of the water repellent used in conjunction with the polyurethane porous film as described above, and to impart durability to the water repellency. For this purpose, the content of polyisocyanates is desirably in the range of 0.2 to 3% by weight, based on the coating liquid. If the amount is less than 3% by weight, sufficient adhesion cannot be obtained and the desired durability of water repellency cannot be imparted, while if it is more than 3% by weight, the adhesion is significantly improved, but the desired durability is not achieved. This is not preferable because the texture of the coated fabric becomes rough and hard. As the nonionic surfactant used in the present invention, commercially available nonionic surfactants can be used, but particularly nonionic surfactants made of blocks of polypropylene glycol and polyethylene glycol give favorable results. .

That is, in the present invention, by including a nonionic surfactant in the coating liquid, the above-mentioned water repellent and additives such as polyisocyanates or pigments have the effect of increasing the compatibility with the polyurethane elastomer solution. It also has the effect of adjusting the elution rate of the solvent in the coating solution into the coagulation bath and the permeation and diffusion rate of water in the coagulation bath into the coating solution when the coating solution is immersed in the coagulation bath. As a result, the diameter of the pores inherent in the produced polyurethane porous film can be reduced to minute pores of 5 microns or less, and most of the water repellent used can be uniformly collected on the surface of the pores. The content of the nonionic surfactant must be in the range of 1 to 8% by weight based on the coating liquid; if it is less than 1% by weight, the effect is insufficient; In the above case, the pore size inside the formed porous film tends to become large, and the water repellent used does not stay on the vaporized surface but tends to flow out into the coagulation bath.

As explained above, in the present invention, by using a polyurethane elastomer solution containing a water repellent, polyisocyanates, and nonionic surfactants in amounts within specified ranges as a coating liquid, these Due to the synergistic effect of the ingredients, the maximum diameter of the many micropores that exist inside the porous film produced by the wet coagulation method is reduced to 5 microns or less, and durable water repellency is imparted to the surface of the pores. Thus, it is possible to easily produce a coated fabric that is durable and has both excellent waterproofness and moisture permeability.

Therefore, as long as it does not interfere with the effects of each of the above-mentioned formulations,
Of course, any commonly used so-called wet coagulation method may be employed, but the concentration of the polyurethane elastomer in the coating solution is preferably in the range of 8 to 25% by weight. That is, as the polyurethane elastomer used as the coating liquid, any polyester-based polyurethane elastomer or polyether-based polyurethane elastomer can be used, but in general, when forming a porous polyurethane film by a wet coagulation method, the concentration and porosity of the polyurethane elastomer are There is a correlation between the diameter of the pores in the pores, and as the concentration decreases, the pore diameter tends to become larger, and conversely, as the concentration increases, the pore diameter tends to become denser. be. In the present invention, the tendency of lever 5 is alleviated by the action and effect of the nonionic surfactant contained in the coating liquid, but if the concentration of the polyurethane elastomer is lower than 8% by weight, the pores inside the porous film On the other hand, if the concentration is higher than 25% by weight, extremely fine pores may be formed, but it is difficult to obtain moisture permeability, which is one of the objectives of the present invention. The disadvantage is that the texture is rubber-like. Although the coagulation bath is not particularly limited, it is advantageous to use an aqueous solution containing 5 to 2% by weight of dimethylformamide. The fiber base materials include woven fabrics, knitted fabrics, non-woven fabrics, etc., and their constituent fibers include natural fibers such as cotton, silk, and wool, chemical fibers such as cellulose, viscose rayon, and Kyupura, polyamide fibers, polyester fibers, Any synthetic fibers such as polyacrylic fibers may be used, or they may be blended or woven.

The present invention will be explained in more detail with reference to Examples below.

Note that all parts in the examples represent parts by weight. In addition, in the examples, the fluorine-based water repellent was Scotchigard FC.
-453 (manufactured by Sumitomo 3M KK) was used. Example 1 15 parts of polyester polyurethane elastomer, 5 parts of fluorine water repellent, 0.8 part of trimethylolpropane-mexamethylene diisocyanate adduct, and 5 parts of polypropylene glycol-polyethylene glycol block (nonionic surfactant) Dimethylformamide 741
Using a reverse roll coater, the coating liquid prepared by dissolving the coating liquid in the nylon taffeta, which had been softened in advance, was coated for about 300 y/day, and immediately introduced into an aqueous solution containing 1% dimethylformamide by volume. After soaking in water at 20°C for 5 minutes to form a gel, it was washed with hot water at 80°C for 3 minutes.
After drying with hot air at 120°C, a coated fabric with a soft texture can be obtained by heat treatment at 140°C.

The obtained product has a water resistance of 160h, crystalline 0/d1, and a water repellency of 10.
01 has excellent waterproof and moisture permeability with a moisture permeability of 2,500 q/24 hours, and has good wash resistance, dry resistance, and leaning resistance, making it suitable for uses such as ski anoraks and raincoats.

This coated fabric was further immersed in a silicone water repellent (TSW-831; manufactured by Toshiba Silicone KK) with a concentration of 3% by weight, and was uniformly squeezed with a mangle to a squeezing rate of 50%, and then with a regular heat setter. At 150℃ (9)
Heat treatment was performed for seconds.

This coated fabric also has a water repellency of 10 on the surface of the woven fabric.
improved to 0.

In Example 1 described above, a dimethylformamide solution containing 15% by weight of 4-polyester polyurethane elastomer was used as the coating liquid, and the coating was applied in the same manner as in Example 1, wet coagulation, hot water washing, and drying to obtain a coated fabric. Ta.

This coated fabric was immersed in an aqueous dispersion containing 5% by weight of a fluorine-based water repellent, uniformly squeezed with a mangle to a squeezing rate of 50%, and then heat-treated at 150°C for (up to) seconds using a heat setter. Let's do it.

The obtained product is inferior in flexibility compared to the product obtained by the above-mentioned method of the present invention, and also has a water resistance of 21071rInH20/d1 and a water repellency of 90 to 1001.
The moisture permeability is 1300 y/d for 24 hours, which is insufficient for waterproofness (especially water resistance) and moisture permeability, making it unsuitable for use as waterproof clothing. (Note) Physical properties were measured according to the following methods.

Water resistance JISL-1079 Water repellency JISL-1079 Moisture permeability JISZ-0208 Example 2 20 parts of polyester polyurethane elastomer, fluorine water repellent and silicone water repellent (SD-8000,
A coating liquid is prepared by dissolving 4 parts each of Toray Silicone KK (manufactured by Toray Silicone KK), 2 parts of isophorone diisocyanate, and 4 parts of polypropylene glycol polyethylene glycol block in 66 parts of dimethylformamide.

This coating solution was applied onto polyester twill for about 200 y/vo using a knife over roll coater, and then introduced into a dimethylformamide aqueous solution with a concentration of 5% by weight, and gelled by water immersion at 30° C. for 5 minutes. Thereafter, after drying with hot air at 120°C, heat treatment was performed at 1400C for 5 minutes.

This coated fabric has moderate flexibility, water resistance of 2000, ugly H2O/d1, water repellency of 100, and moisture permeability of 25.
It has excellent waterproofness and moisture permeability between 00q/d and 2@, and these physical properties show almost no deterioration even after washing 5 times according to JISL-0844 (A-2). It is suitable as waterproof clothing.

In addition, in Example 2, isophorone diisocyanate 2
A flexible coated fabric was obtained by carrying out the same treatment using the same formulation as in Example 2, except that it contained no particulate matter.

This fabric has almost the same physical properties as the fabric obtained in Example 2, but after washing, it has a water resistance of 500 TrI1n.
H20/d, water repellency 50, the waterproof property is significantly lowered, making it unsuitable for practical use. Example 3 A nylon fabric with weft stretchability was immersed in 100 parts of an aqueous dispersion containing 3 parts of a fluorine-based water repellent, uniformly squeezed with a mangle to a squeezing rate of 40%, and then heated to 150°C with a heat setter. Heat treatment is performed for (up to) seconds at .

15 parts of polyether polyurethane elastomer, 5 parts of fluorine water repellent, 2 parts of trimethylolpropane-hexamethylene diisocyanate adduct, 2 parts of nonionic surfactant
A coating solution prepared by dissolving 100% of dimethylformamide in 76 parts of dimethylformamide was applied on the water-repellent treated base material for about 70y/d using the gravure printing method, and immediately immersed in water for 5 minutes. After being gelled by water immersion, it was dried with hot air at 120°C and heat treated at 140'C for 5 minutes.

The resulting coated fabric is extremely flexible and has excellent drapability, with a water resistance of 80 and a mountain of 0/d1 of 100. It has excellent moisture permeability and waterproofness with a moisture permeability of 3,800 V/I. be.

Example 4 20 parts of polyester polyurethane elastomer, 5 parts of fluorine water repellent, 0.8 part of trimethylolpropane-hexamethylene diisocyanate adduct, and 5 parts of polypropylene glycol-polyethylene glycol block (nonionic surfactant) Dimethylformamide 691
Using a knife-over roll coater, the coating liquid prepared by dissolving the coating solution in 100% of dimethylformamide was applied to a fabric made of polyester/cotton blend yarn at 250y/771', and immediately introduced into an aqueous solution containing 5% by weight of dimethylformamide. 5 at °C
After soaking in water for a minute to form a gel, wash it in hot water at 80℃ for 30 minutes,
After drying with hot air at 120°C, heat treatment was performed at 140°C.

(Product No. 1) The water resistance of the obtained product is 2700Tf
0fL 0/d1 moisture permeability is 2700y/d・24 hours,
The water repellency was 100.

As a precaution, this coated fabric was immersed in a silicone emulsion with a concentration of 2% by weight, squeezed uniformly with a mangle to a squeezing rate of 50%, and then heat-treated at 150°C for 30 seconds using a regular heat setter. .

In the case of this coated fabric, the water repellency on the surface of the woven fabric was improved from 0 to 100. On the other hand, in the coating liquid of Example 4, the concentration of the polyester polyurethane elastomer was changed to 7.5 parts (product no. 2), 15 parts (product no. 3), and 27 parts (product no. 4), respectively. Accordingly, 81.7 parts of dimethylformamide,
74.2 parts, 62. ? A coated cloth was obtained by carrying out the same treatment using the same recipe as in Example 4 except for the following changes. The physical properties of the obtained product are shown in the table.

However, in each case, the comparison was made without post-treatment with silicone emulsion. As is clear from the table,
No. 1 that satisfies the present invention. l and NO. Product No. 3 has well-balanced water resistance and moisture permeability, making it an excellent waterproof and breathable garment.

On the other hand, product No. 2 has insufficient water resistance,
Also, product No. No. 4 had insufficient moisture permeability, and it was not possible to obtain a material that satisfied both water resistance and moisture permeability.

Claims (1)

[Scope of Claims] 1. A coated fabric having a microporous film made of a synthetic polymer mainly composed of a polyurethane polymer on at least one side of a fiber base material, the coated fabric having a water resistance of 800 mmH_2O/cm. ^2 or more, 300m
mH_2O/cm^2 or less, moisture permeability is 2500g
A moisture-permeable and waterproof coated fabric characterized by having a resistance of at least 4,800 g/m^2 for 24 hours and at most 4800 g/m^2 for 224 hours. 2 A polar organic solvent solution of polyurethane elastomer is used as a coating liquid, and the coating liquid is applied or impregnated onto a fiber base material, and then immersed in a coagulation bath to gel, and then washed with water and dried to produce a coated fabric. In the method for producing a coating liquid, 1 to 10% by weight of a water repellent that is stable at 40°C or lower and reactive at 100°C or higher, and 0.2 to 3% by weight of polyisocyanates, based on polyisocyanates as a coating liquid. A polar organic solvent solution with a concentration of 8 to 25% by weight of a polyurethane elastomer containing 1 to 8% by weight of a nonionic surfactant is used, and the coating solution is wet coagulated, washed with water, dried, and then heat treated at a temperature of 100°C or higher. The water resistance of the coated fabric is characterized in that the diameter of the fine pores inherent in the resulting polyurethane porous film is 5 microns or less, and durable water repellency is imparted to the surface of the fine pores. is 800mm
H_2O/cm^2 or more, 3000mmH_2O/cm
A method for producing a moisture permeable and waterproof coated fabric having a moisture permeability of 2500 g/m2 for 24 hours or more and 4800 g/m2 for 24 hours or less.