FIELD OF THE INVENTION

The invention relates to membranes useful for clothing or garments which are waterproof, water vapor permeable, and will not become malodorous in continuous heavy service.

BACKGROUND OF THE INVENTION

Owing to the fact that waterproof, water vapor permeable cloth not only prevents the penetration and adhesion of rainwater, but also allows the vapor content produced from perspiration to permeate, such cloth is highly adapted for manufacture of clothing which is comfortable to wear in continuous heavy service. Various examples of such clothing that have been wet-coated with poly- urethane or laminated with microporous polytetrafluoroethylene (PTFE) film have been illustrated in Japanese Patent Publication Nos. 58-38456, 60-47955 and 60-39014. Such clothing is being used on a commerical scale.

Cloth produced according to the methods cited above can be supplied for use in clothing adapted for comfortable wear without causing the wearer any feeling of stuffiness when the wearer perspires. This is based on the fact that the clothing is waterproof and water vapor permeable allowing water vapor permeation therethrough. However, when the clothing is worn in surroundings where unpleasant odors are present, such as the farming and dairy industries, malodorus components end up adhering to the skin of the worker. Even after the worker's job has ended, said odors emanate from the body and underwear of said worker, and naturally cause discomfort to those in the worker's immediate surroundings. The penetration and adhesion of malodorous components cannot be prevented in the case of clothing utilizing water vapor permeable sheets of the above type.

BRIEF DESCRIPTION OF THE INVENTION

The present invention comprises a membrane manufactured by coating a microporous organic polymer membrane selected from

microporous polytetrafluoroethylene membrane or a polyolefin membrane with a hydrophilic resin which contains a deodorant admixed there n, to produce a liquid-waterproof water vapor permeable deodorizing membrane, useful for garments or clothing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

It has been found that hydrophilic resins uniformly admixed with a deodorant can be coated onto a microporous PTFE membrane or a microporous polyolefin membrane. The deodorant, which is mixed uniformly in the hydrophilic resin, acts to remove odors. In other words, a membrane is obtained hav ng a superior deodorizing function.

When PTFE is the microporous membrane it can be obtained as a material in which countless fine fibers are formed in a spi er web-like pattern between micronodes by fibriHating a- PTFE sheet by rolling or drawing (or by using both together). Membranes having the following specifications can be employed: pore percentage 50 to 95%; maximum pore size OJ to 3 um; thickness 10 to 200 um.

Polyether polyurethane resin or polymeric perfluorosulfonic acid or the like are useful as the hydrophilic resin.

A deodorant such as a metallic oxide salt (such as copper oxide or iron oxide), a metallic salt (such as phthalocyanine salt), and an organic acid (such as an aliphatic or aromatic

2 carboxylic acid) in the amount of 5-100 g/m of a mixture of 1-200 parts by weight per 100 parts by weight of the hydrophilic resin is then coated onto the microporous PTFE membrane. The mixture can be applied by spraying, brushing, or roll-coating.

EXAMPLE

A membrane was prepared by coating a mixture of 30 parts by weight of a copper oxide-type deodorant blended with 100 parts by 'weight of a polyether polyurethane resin (a hydrophilic resin) onto a microporous PTFE membrane which was obtained by a drawing process such that the maximum pore size was approximately 0.2 m,

the pore percentage was as much as 80%, and the thickness was approximately 35 um.

The water pressure resistance and permeation capacity of the membrane obtained above are shown in Table 1. The membrane had desirable water-proof moisture permeability.

Tabl e 1

Capaci ty Method of Measurement

Water Pressure Resi stance (kg/crfr ) 30 JIS L-1092 Moi sture Permeabili ty (g/f? « 24 hr) 60,000 JIS L-1099 B Method

The membrane obtained as above was measured in terms of its deodorizing property vis-a-vis the following malodorous components: ammonia, trimethylamine, and hydrogen sulfide. The methods for measuring this property are as described below.

A) Ammonia

10 ml of 28% aqueous ammonia was placed in a 300 ml Erlenmeyer flask. After the ammonia had completely vaporized, approximately 1 g. of sample was added thereto and the temperature maintained at 25°C. After 2 hours had elapsed, the residual ammonia concentration in the flask was measured by a Kitagawa-type gas detector.

B) Trimethylamine

10 ml of an 0.8% trimethylamine aqueous solution was, placed in a 300 ml Erlenmeyer flask. Following the same procedure as for ammonia, the residual concentration of trimethylamine in the flask was measured by a Kitagawa-type gas detector.

C) Hydrogen Sulfide

Hydrogen sulfide was formed by placing 1 ml of an 800 ppm hydrogen sulfide aqueous solution and OJ ml of 1 N sulfuric acid in a 300 ml Erlenmeyer flask, after wh ch approximately 2 g. of sample was added thereto. The mixture was maintained at 25 ^β C.

After two hours had elapsed, the residual concentration of the hydrogen sulfide in the flask was measured by a Kitagawa-type gas detector.

The results from each of the above measurements are shown in Table 2.

A fabr c was prepared by laminating the above membrane produced eiccordirtg to the present invention with _, 40 denier knitted fabric. The properties of this laminated cloth were tested and measured, with the results shown in Table 3. These results confirmed that the sample was water-proof, had moisture permeability desirable for use in all types of work clothes, and had superior deodorizing capabilities.

Table 3

Water Pressure Resistance 3__Jc_/_m_

Moisture Permeabil y 30.000 q/m2 - 24 hours

Deodorizing Capability Ammon a Blank 6,000 Sample 120

Tri methyl ami ne Blank 32 Sanipl e ND

Hydrogen Sulfide Blank 140 Samp e ND

(ND - not detected)

Work clothes and the like which are used in malodorous surroundings can be furnished with desirable waterproof and moisture permeability properties so as to provide comfort during work while wearing such clothes. Furthermore, it is possible to obtain a product which has odor-preventing properties and in which no unpleasant odors are left on the body of the wearer or on the wearer's undergarments. Such garments are highly useful in an industrial environment.