JPS61239084A - Production of air permeable coated molded article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a coated molded article with excellent air permeability and moisture permeability. For base materials such as waterproof clothing, artificial leather, diaper covers, and packaging materials, coated molded products with excellent breathability and moisture permeability are required from the viewpoint of hygiene and comfort.

Various proposals have been made to coat or impregnate a base material with a coating agent to obtain a coated molded article that has excellent moisture permeability and air permeability, and is free from stuffiness and discomfort due to perspiration. For example, JP-A-59-17
9512, in which the solvent is coated or impregnated in a solvent mainly composed of dimethylformamide, and then the solvent is removed by a wet method; or, as in JP-A-58-203173, polyvinylpyrrolidone is present in the urethane prepolymer. At present, methods for removing polyvinylpyrrolidone after coating or impregnation, and other solvent-based coatings, are currently in use, and at present, air-permeable and moisture-permeable coated molded products using a water-based emulsion type are hardly seen.

Problems that Ming aims to solve: Conventional organic solvent-based coating compositions used to produce breathable coated moldings pose problems such as air pollution due to large amounts of solvent splashing, fire hazards, and the use of solvents. There are many problems that need to be improved, such as high prices.

Means and action for solving the problems The inventors have developed synthetic leather with excellent moisture permeability and air permeability, highly moisture permeable waterproof material, composite film with excellent water vapor and gas permeability, diapers, diaper covers, The present invention was developed as a result of various studies on making water-based coating compositions for waterproof clothing and the like.

The present invention is directed to one or two emulsions selected from acrylic copolymer emulsions, ethylene-vinyl acetate copolymer emulsions, urethane emulsions, and butadiene copolymer emulsions, which are mainly used as coating agents for cloth, nonwoven fabrics, etc. If kerosene or mineral turpentine is added to the amount of kerosene or mineral turpentine and the uniformly emulsified composition is applied or impregnated onto a molded product, an air-permeable and moisture-permeable coated molded product can be easily obtained, and the use of kerosene or mineral turpentine can be easily obtained. We discovered that breathability and moisture permeability can be easily controlled by increasing or decreasing the amount.

The acrylic copolymer emulsion used in the present invention is a copolymer emulsion of ethyl acrylate, butyl acrylate, or 2-ethylhexyl acrylate and other copolymerizable monomers such as methyl methacrylate and acrylonitrile. It is a copolymerized emulsion of ethylenically unsaturated carboxylic acid, such as (meth)acrylic acid, (meth)acrylamide, hydroxyethyl (meth)acrylate, etc. as a base, and as an ethylene-vinyl acetate copolymer emulsion, the ethylene content is 10-30% by weight
, about 90 to 70% by weight of vinyl acetate, ordinary ethylene-
Vinyl acetate copolymer emulsions are suitable, and urethane emulsions include anionic types that do not contain an emulsifier such as those disclosed in JP-A-53-47495 and JP-B-52-41320, and self-emulsifying nonionic urethanes such as JP-A-52-40358. emulsions are preferred. Or,
Emulsions obtained by emulsion copolymerization of acrylate monomers in an aqueous polyurethane resin solution as disclosed in JP-A-54-77795 are also suitable. Next, butadiene copolymer emulsions such as acrylonitrile-butadiene copolymer latex, styrene-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, etc. are also preferred, but they are used for back coating etc. from the viewpoint of weather resistance. It is necessary to take this into consideration.

Moreover, there is no problem in using the above emulsions together. The kerosene or mineral turpentine used in the present invention is
Any commercially available gasoline may be used, ranging from Japanese Industrial Standard No. 1 equivalent to white kerosene to Japanese Industrial Standard No. 4 industrial gasoline, with industrial gasoline No. 4 being preferred in terms of volatility.

When used, the emulsion contains an emulsifier or is self-emulsifying, so it can be easily dispersed by increasing or decreasing the amount of kerosene or mineral turpentine according to the moisture permeability and uniformly emulsifying it with a homomixer. At that time, the emulsifier is preferably
The use of non-ionic activators is equally problematic. When applying the emulsion thus obtained, it is preferable to use a crosslinking agent. Suitable crosslinking agents include water-soluble melamine-formalin initial condensates, water-soluble or emulsion-type epoxy resins, and polyaziridine compounds. Furthermore, if necessary, surfactants, water-boosting agents, coloring agents, and other additives may be added to the emulsion in advance.

As a base material, natural fibers such as cotton and hemp and their derivatives,
One or two types of silk, wool, natural leather, synthetic leather, polyamino acids, polyamides, polyurethanes, polyesters, acrylonitrile polymers, vinyl chloride polymers, polyvinyl alcohol, synthetic rubber, glass, metals, etc. Examples include mixtures of the above. The shape of the base material can also be selected depending on the purpose, such as film, plate, fiber, or porous.

Generally used methods such as dipping or coating are sufficient for applying the coating composition, but various methods such as doctor knife coating or pre-coating on release paper and semi-drying and transferring to the substrate are possible. It will be done.

The coating thickness varies depending on durability, air permeability, etc., but a dry film thickness of around 50 microns is suitable.

Air permeability is believed to be caused by the uniform dispersion of kerosene or mineral turpentine in the coating composition, which does not dissolve the resin, and the formation of fine, uniformly distributed holes in the coating surface after application and drying. The coated molded product thus obtained has excellent moisture permeability, waterproofness, gas permeability, gas separation property, mechanical strength, etc., and the type of base material,
By appropriately selecting the type of emulsion and the amount of kerosene or mineral turpentine, it can be applied to various applications. Examples of such applications include synthetic leather, waterproof clothing, tents, packaging materials, diaper covers, and moisture-permeable materials. It can be applied to composite films for occlusive bandages, separation materials for liquid or gas mixtures, etc. Hereinafter, the present invention will be specifically explained with reference to Examples, where parts or % indicate parts by weight or % by weight.

Large 11 pull-” Urethane emulsion In+pranil DLS
Dispersion [Anionic aliphatic polyester polyurethane aqueous dispersion manufactured by Bayer Japan Co., Ltd.] 10
To 0 parts, 50 parts of mineral turpentine and 5 parts of a nonionic surfactant, Liponox NCR (polyoxyethylene alkylphenol ether type manufactured by Lion Corporation) were added, and the mixture was stirred at high speed with a homomixer and emulsified to form an emulsion. I got it.

This emulsion has a nonvolatile content of 35.5% and a pH of 7.
, the viscosity was 12,000 cps (30°C).

``Daishika'' - Acrylic copolymer emulsion with a composition of 87% methyl acrylate and 13% acrylonitrile (50% non-volatile content) 1
00 parts, 30 parts of kerosene was added, and the mixture was stirred at high speed in a homomixer and emulsified to obtain an emulsion. This emulsion has a nonvolatile content of 40%, a pH of 7, a viscosity of 8, and 0O
Ocps (30°C).

In each Example 1.2, the emulsion before addition of mineral turpentine or kerosene was used as Comparative Examples 1 and 2, and the water vapor permeability (J
rS Z 0208-1976 method) were compared.

The results were as shown in the table.

According to the present invention, the solvent other than kerosene or mineral turpentine is water, and it can be manufactured at low cost. Unlike solvent-based products, air pollution caused by large amounts of solvent being scattered can be minimized. In order to improve moisture permeability and air permeability, there are limits to the introduction of hydrophilic resin components, so this is an extremely simple method to improve moisture permeability and air permeability while maintaining the originally required physical properties of the coating composition. It is.

Claims (1)

[Claims] Kerosene or mineral turpentine is added to one or more emulsions selected from acrylic copolymer emulsions, ethylene-vinyl acetate copolymer emulsions, urethane emulsions, and butadiene copolymer emulsions to form an emulsified composition. A method for producing a breathable coated molded article, characterized in that it is obtained by coating or impregnating an object.