JPS6354829B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for processing a moisture-permeable, waterproof coating, and more specifically, to a processing method that can provide a moisture-permeable, waterproof coating with excellent peel strength to a fiber base material. Traditionally, waterproof fabrics made of fibers coated with natural rubber, synthetic rubber, acrylic resin, or polyurethane resin have been used for waterproof clothing such as raincoats, bonnets, and ski wear, as well as tents, tarpaulins, and other industrial materials. There is. However, these waterproof fabrics have poor moisture permeability, and waterproof clothing such as raincoats, jackets, and ski wear can become stuffy due to sweating when worn, causing extreme discomfort. In addition, industrial materials such as tents have drawbacks such as water vapor condensing inside them because they have no practical moisture permeability. On the other hand, waterproof fabrics that emphasize moisture permeability include fabrics with a high-density structure that are simply treated with water repellency, but the water pressure resistance varies slightly depending on the fabric's fabric density, but in general,
It is difficult to obtain water resistance of 150mmH ₂ O. Furthermore, a processing method is known in which a porous membrane is formed from a synthetic resin by adding various foaming agents and others, but this processing method produces spherical or elliptical pores, and Since the pore size is large and most of the pores are independent, it has the disadvantage that it is difficult to obtain sufficient air permeability and moisture permeability. Furthermore, Japanese Patent Publication No. 45-3299 describes a manufacturing method for imparting air permeability and moisture permeability to a polyurethane polymer by applying a solution of isocyanates added to a polar organic solution of a polyurethane polymer, and then immersing it in an aqueous solution. A coagulation method that forms a microporous film has been proposed. However, with this method, the stability of the viscosity of the solution over time is poor, and coating unevenness is likely to occur, resulting in unstable quality. Also, isocyanates and water react with each other in the aqueous solution and are extracted into the aqueous solution, resulting in weak adhesive strength with the base fabric, which has no inherent crosslinking effect, and the film peels off. Therefore, there are problems when it comes to uses such as materials for the clothing industry. In order to solve these drawbacks, JP-A-Sho proposed a method in which isocyanates and phenols or nonionic surfactants are added to polyurethane polymers to form blocked isocyanates, which are coagulated in a water bath.
No. 55-80583. In this processing method, isocyanates and water do not react in an aqueous solution, but the blocked isocyanate does not dissociate unless high-temperature heat treatment of 170°C or higher is performed in the drying and heat treatment steps. However, heat treatment at a high temperature of 170°C or higher causes problems such as discoloration and deterioration of the urethane polymer, making high-temperature heat treatment impossible in practice. For this reason, the above-mentioned block isocyanate does not dissociate under the heat treatment conditions of the working process at 140 to 150° C., and is not completely crosslinked, so that no improvement in the peel strength between the base fabric and the coating is observed. The present invention provides a coating method that improves the above-mentioned drawbacks and provides excellent moisture permeability and waterproof properties. According to the present invention, a moisture-permeable and waterproof coating processing method is provided, which comprises: polyurethane elastomer in an organic polar solvent;
Isocyanate and alcohol are dissolved and mixed to form a coating liquid, this coating liquid is applied or impregnated onto a fiber base material, and then this is immersed in a coagulation bath,
It is then characterized by washing with water, drying, and heat treating. That is, a solution prepared by adding predetermined amounts of isocyanates and alcohols, preferably aliphatic alcohols, to a polyurethane polymer solution is applied onto a base fabric, and then immersed in an aqueous solution to solidify the porous material. This is a coating processing method that forms a durable film with excellent moisture permeability, waterproofness, and peel strength by forming a high-quality film, followed by drying and heat treatment. Preferably, the polyisocyanates added to the polyurethane polymer solution include compounds having two or more isocyanate groups, such as diisocyanates and triisocyanates, which are stable at 40°C or lower, such as 2,4- Or 2,6
- Diisocyanates such as tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,4-naphthalene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and compounds having 3 moles of these diisocyanates and active hydrogen (for example, trimethylolpropane, It can be arbitrarily selected from triisocyanates obtained by an addition reaction with 1 mole of glycerin, etc.). These are preferably added in an amount of 1 to 10 parts by weight, preferably 5 to 8 parts by weight. The aliphatic alcohol can be arbitrarily selected from, for example, methanol, ethanol, propanol, butanol, octyl alcohol, etc., and these can be used in an amount of 1 to 10 parts by weight, preferably 5 to 8 parts by weight. It is best used in quantity. A solution obtained by weighing and mixing these is coated onto the base fabric using a coating machine such as a knife coater, pipe coater, or reverse roll coater, and then immersed in a water bath for coagulation.
A polyurethane polymer porous film with micropores of 5 microns or less in diameter is formed. Next, dry this for 3 to 10 minutes within the range of 120 to 150°C, preferably
Heat treatment in the range of 140 to 150°C for 5 to 7 minutes yields a moisture permeable and waterproof coated fabric with excellent peel strength. To explain the present invention in more detail, immersion coagulation of isocyanate groups in a free form in a polyurethane polymer solution means that the isocyanate groups and water easily react with water and are extracted into the coagulation solution, resulting in a crosslinking effect. completely disappears. Therefore, if the isocyanate group is first blocked so that it does not react with water, the isocyanate group will not react with water and will not be easily extracted into an aqueous solution.Therefore, the crosslinking agent will remain and the crosslinking effect will appear, resulting in excellent peel strength. Therefore, it is possible to form a film with a high temperature. However, unless the blocked isocyanate is dissociated by heat treatment, a sufficient crosslinking effect will not occur. The present invention aims to improve the above-mentioned drawbacks. For example, by mixing 1 to 10 parts by weight of isocyanates and 1 to 10 parts by weight of aliphatic alcohols in a polyurethane polymer solution, blocked isocyanates can be prepared. The prepared solution is applied to a base fabric, i.e., a knitted fabric, using a reverse roll coater, etc., and immersed in a coagulation bath for 10 to 20 minutes at a temperature range of 10 to 30°C, and then dried at a temperature of 100 to 150°C for 3 By performing heat treatment for ~5 minutes, a moisture permeable and waterproof coated fabric with excellent peel strength can be obtained. The invention will now be further explained by way of examples. Example 1 100 parts of polyurethane polymer CR8006HV (Dainippon Ink & Chemicals Co., Ltd.), 50 parts of dimethylformamide,
A solution was prepared by mixing 5 parts of coronate (Nippon Polyurethane Industry Co., Ltd.) as an isocyanate and 5 parts of isopropyl alcohol, and this was coated on nylon taffeta (210 class) using an over-knife roll coater, and the temperature was lowered in a coagulation tank. Solidify at 20°C for 10 minutes, then dry (150°C x 1 minute) and heat at 150°C.
Heat-treat for 3 minutes. After that, a fluorine-based water repellent (Asahi Guard AG710, Asahi Glass Co., Ltd.) 3% OWS is applied and heat treated. As a result, as shown in Table 1, a fabric with excellent peel strength, moisture permeability, and waterproof properties was obtained.

[Table] In the comparative example, the same operation as above was repeated except that isopropyl alcohol was not used. Example 2 100 parts of polyurethane polymer CR8006HV (Dainippon Ink & Chemicals Co., Ltd.), 50 parts of dimethylformamide,
A solution was prepared by mixing 5 parts of coronate (Nippon Polyurethane Industry Co., Ltd.) as an isocyanate and 5 parts of methanol, and it was coated on nylon taffeta (210 pieces) using an over-knife roll coater, and coated in a coagulation tank at a temperature of 30°C for 10 minutes. After coagulating for minutes, it is then dried (150°C x 1 minute) and heat treated at 140°C for 5 minutes.
After that, heat treatment is applied by applying a fluorine-based water repellent (Asahi Guard AG710 manufactured by Asahi Glass Co., Ltd.) 3% (OWS). As a result, as shown in Table 2, a fabric with excellent peel strength, moisture permeability, and waterproof properties was obtained.

[Table] A comparative example is a case where methanol was not used in the above operation.

Claims (1)

[Scope of Claims] 1 A coating solution is obtained by dissolving and mixing a polyurethane elastomer, isocyanate, and alcohol in an organic polar solvent, and this coating solution is applied or impregnated onto a fiber base material, and then this is applied to a coagulation bath. A moisture-permeable and waterproof coating processing method characterized by immersing the coating in water, followed by washing, drying and heat treatment. 2 Isocyanate group as isocyanate
2. The method according to claim 1, wherein a compound having 1 or more is used. 3. The method according to claim 1, wherein an aliphatic alcohol is used as the alcohol.