JPS61201082A - Water-repellent cloth and its production - 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 fabric having excellent waterproofness and moisture permeability, and a method for manufacturing the same.

(Prior art) Waterproof fabrics are fiber base materials coated with resin and have been widely used for clothing and industrial purposes.In recent years, waterproof fabrics have been used not only for raincoats but also for sports clothing, casual coats, and mountain climbing equipment. , marine wear, etc. The reason why it has become so popular for use as clothing is that it not only has a softer feel, but also has moisture permeability, which is a property contradictory to waterproofness. In other words, the biggest drawback of waterproof fabrics is the stuffiness that occurs when exercising in the rain during rainy days. Therefore, by creating a III-type structure that does not allow water droplets to pass through, but allows steam to pass through, it provides two functions. However, the reality is that increasing moisture permeability and eliminating the stuffy feeling comes at the cost of reducing waterproofness. In terms of structure, if you increase the number of areas through which steam can pass, not only will the waterproofness decrease, but the strength of the coating itself will also decrease.

[Problems to be Solved by the Invention] The present invention provides a fabric that satisfies both moisture permeability and waterproofness. The invention provides a particularly high level of moisture permeability -
It can be applied without reducing waterproofness.

[Means for Solving the Problems] The present invention solves the above problems by adopting the following configuration.

(1) Oblong cavities with a maximum length of 1 to 10 μ in the entire coating film made of polyurethane-modified amino acid resin,
A waterproof fabric characterized by having micropores with a maximum length of less than 1μ distributed in a mixed manner.

(2) The waterproof manufacturing method according to claim (1), which comprises adding water to the polyurethane-modified amino acid resin at a rate of 15% or less based on the resin content, and then performing wet coating.

The present invention uses a polyurethane-modified amino acid resin to wet-coat a fiber base material under specific conditions to form a coating with a new pore structure, achieving an unprecedentedly high level of waterproofness without compromising waterproofness. It has moisture permeability.

The polyurethane-modified amino acid resin referred to in the present invention is one obtained by copolymerizing a polyurethane resin consisting of a polyol component and a diisocyanate component and γ-alkylglutamate-N-carboxylic acid anhydride.

Organic diisocyanates include aromatic and aliphatic types, and aromatic types are preferable in terms of solvent resistance, such as 4,4'-diphenylmethane diisocyanate, 2.
4-Toluylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, m-
Xylylene diisocyanate, 3,3'-dimethyl-4
, 4'-diphenylmethane diisocyanate, 3,3
'-dimethyl-4,4'-biphenyl diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, hexamethylene diisocyanate and the like.

Diol components are broadly classified into polyester and polyether. The polyester diol component forms a film with excellent light resistance, heat resistance, and solvent resistance, and includes, for example, polyethylene adipate glycol, polyethylene propylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate glycol,
Examples include polycaprolactone glycol.

Further, the polyether diol component forms a film with excellent hydrolysis resistance, and includes, for example, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like. Other diol components that roughly improve light resistance, heat resistance, solvent resistance, chemical resistance, and hydrolysis resistance may be added and blended.

Further, as the above-mentioned γ-alkylglutamate-N-carboxylic acid anhydride, for example, γ-methylglutamate N-
γ-lower alkyl such as carboxylic anhydride, γ-ethylglutamate-N-carboxylic anhydride, γ-propylglutamic acid 1--N-carboxylic anhydride, γ-butylglutamate-N-carboxylic anhydride, etc. Examples include one or a mixture of two or more glutamate N-carboxylic anhydrides.

Such acid anhydride is used in an amount of 7 to 7 to 100 parts of polyurethane.
A copolymerization of 85 parts, preferably 30 to 50 parts is preferred from the viewpoint of achieving the object of the present invention.

A polyurethane film modified with such an acid anhydride has the advantage of uniformly dispersing micropores in the film, and at the same time has the effect of improving heat resistance, light resistance, and tactile properties.

The present invention is a waterproof fabric having such a polyurethane-modified amino acid resin as a coating, and is characterized in that the coating has a mixture of relatively large cavities and micropores distributed throughout the membrane.

Relatively large cavities are oblong pores with a maximum length of 1 to 10 μm, and microporous means pores with a maximum length of less than 1 μm.

In the present invention, the moisture permeability can be greatly improved by distributing the microporous throughout the membrane.

The thickness of such a coating film is at least 10
[mu], preferably 15 to 50 [mu], particularly 20 to 30 [mu], selected from those that simultaneously achieve waterproofness and moisture permeability.

The pore structure of the coating film of the present invention will be explained using a photomicrograph.

FIG. 1 is a 3000 times enlarged view of the surface of the coating film obtained in Example 3 of the present invention.

As is clear from this figure, the surface of the coating of the present invention is extremely roughened with cavities and micropores, and is characteristic in that it exhibits a random, intertwined state similar to the internal structure of synthetic leather. It is.

FIG. 2 is a cross section of FIG. 1 enlarged 1500 times. From both of Figures 1 and 2, it can be clearly seen that relatively large cavities and micropores are mixed and distributed throughout the coating.

On the other hand, FIG. 3 shows the conventional polyurethane wet coating obtained in Comparative Example 1 enlarged 3000 times. FIG. 4 is a 1500 times enlarged view of the cross section. The surface of this conventional coating is extremely smooth compared to that of the present invention, and although there are cavities in the cross section, there are no micropores, and the two have completely different pore structures and surface structures. I understand.

The present invention is the first to achieve excellent waterproofness and moisture permeability at the same time by employing a coating having such a membrane structure.

Fabrics with such coatings on their surfaces include woven fabrics, knitted fabrics, and non-woven fabrics, and their constituent fibers include natural fibers such as cotton, silk, and wool, chemical fibers such as cellulose and viscose rayon, or polyamides. Any synthetic fiber such as polyester or polyacrylic may be used, or a blend or interweave of these fibers may be used.

Next, a method for manufacturing the waterproof fabric of the present invention will be explained.

First, the polyurethane-modified amino acid resin of the present invention is synthesized.

For polyurethane, a prepolymer is synthesized from the organic diisocyanate component and diol component, and this is reacted in a solvent containing a chain extender to obtain a polyurethane solution.

The chain extender is a compound containing two or more active hydrogen atoms in its molecule, such as a primary amino group, a secondary amino group, a hydroxyl group, a carboxyl group, an active methylene group, and the like.

It is essential that the solvent used in the present invention is a water-soluble organic solvent. Moreover, in addition to dissolving the polyurethane, the resulting polyγ-
It is necessary to select a solvent that dissolves the alkyl glutamate and does not inhibit the polymerization of the γ-alkyl glutamate-N-carboxylic anhydride. Among those that satisfy these conditions, dimethylformamide is most preferred.

A polymerization initiator is added to the polyurethane solvent solution, and the γ-
Add alkylglutamate-N-carboxylic acid anhydride and polymerize.

As the polymerization initiator, those commonly used in the polymerization of γ-alkylglutamate can be used. Examples include various amines such as triethylamine, tri-butylamine, triethylenediamine, and jetanolamine, and alkali metal compounds such as sodium hydroxide and potassium hydroxide.

γ-alkylglutamate N-carboxylic acid anhydride is 1
Species or mixtures of two or more species may be used.

Water and a crosslinking agent are added to the polyurethane-modified amino acid resin obtained as described above, and the mixture is roughly diluted with dimethylformamide to adjust the coating liquid to an appropriate viscosity.

Water has great significance in improving moisture permeability, and acts to form micropores of 1 μm or less in the pore structure of the film. Since gelation occurs when the amount of water added is increased, the amount is preferably 15% or less, particularly preferably 5 to 10%, based on the weight of the polyurethane-modified amino acid resin.

The above-mentioned crosslinking agent not only improves the adhesion between the coating and the fiber base material, but also has a waterproof effect.

The higher the amount added, the better the above effect will be, but the moisture permeability and texture will be lowered, so it is preferable to keep it at 10% or less.

As such a crosslinking agent, block compounds of the above-mentioned organic diisocyanates and other polyfunctional isocyanates are selected. For example, diisocyanates such as 2,4-(2,6) tolylene diisocyanate, diphenylmethane 4,4'-diisocyanate, 1,4-naphthalene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and 3 moles of these diisocyanates and active hydrogen It can be arbitrarily selected from the compounds contained therein, such as triisocyanates which can be quenched (by addition reaction of 1 mole of trimethylolpropane, glycerin, etc.). As blocking agents for these isocyanates, commonly used ones may be used, but one such as oxime, etc.
It is preferable to use one that desorbs at a high temperature of 00°C or higher. The coating liquid prepared in this manner is directly applied to the fabric, or a film is formed using a lamination method. There are no restrictions on the coating method, and for example, a floating knife coater, knife over roll coater, reverse roll coater, roll doctor coater, etc. can be applied.

In addition, in the present invention, addition and blending of a water repellent into the coating liquid as in the prior art should be avoided. That is, the polyurethane-modified amino acid resin of the present invention is characterized in that the coexistence of such a water repellent reduces the flowability of the coating liquid, making it impossible to form a uniform coating.

In addition, if the fabric is lightly water-repellent treated or treated with a calendar roll before coating, it will control the penetration of the resin into the fiber base material.
It suppresses texture hardening and also exhibits waterproof effects. There is no limit to the density of the fabric, but JIS-Z0 is recommended in terms of waterproofness.
It is preferable that the moisture permeability based on 208 is 7000Q/m2·24hr or more.

After applying the coating liquid to the fiber base material as described above,
Wet coagulation is carried out in a coagulation bath of water or water containing dimethylformamide. When forming a film with a porous structure according to the present invention, the temperature of the coagulation bath is preferably 30° C. or lower, and the concentration of dimethylformamide is preferably 5% or lower. When the temperature and concentration exceed the above conditions, there is a tendency for the moisture permeability to decrease and the texture of the coating itself to become hard. After wet coagulation, it is washed in hot water and dried while performing mangle squeezing.

Thereafter, water resistance can be improved by subjecting the film to water-repellent treatment with water-based or solvent-based silicone or fluororesin.

The above-mentioned fluorine-based compound includes C)(2=C COOY CW F 2n +i (wherein, R is hydrogen or an alkyl group having 1 to 4 carbon atoms, and Y contains an alkylene group having 1 to 6 carbon atoms. The basis for
π represents an integer from 1 to 30. ) Also, as a silicon-based compound, Z R'R' -3i O-3i -R' Z R' (wherein R' is hydrogen, a hydroxyl group, a methyl group, a methoxy group,
Either ethyl group, ethoxy group or phenyl group, Z
represents hydrogen or an organic group, and l represents an integer of 1 or more. ) etc. apply.

In terms of waterproofness and durability, fluorine-based water repellents are better than silicone-based ones, and the application method is to alternately repeat impregnation and mangle squeezing many times to uniformly adhere to the inside of the film to improve waterproofness. Leads to.

The heat treatment temperature after water repellent finishing is preferably 120°C to 160°C.

If the temperature is high, the moisture permeability will decrease, and if the temperature is low, the durability of the water repellent will deteriorate.

The amount of water repellent applied to the coated fabric is 0.
It is sufficient if it is 0.02% by weight or more, usually 0.04 to 1% by weight.
It is.

[Function] The film of the polyurethane-modified amino acid resin of the present invention has a higher porosity on the film surface and cross section than conventional polyurethane resins, and has a porosity of 1 to 10μ horizontally long cavities and the resin portion forming the cavities. It is characterized by the fact that micropores of 1 μm or less are uniformly mixed throughout the coating, which makes it possible to obtain high moisture permeability. Moreover, the amino acid resin itself has high moisture permeability compared to polyurethane, and this synergistic effect provides high moisture permeability.

[Example] Examples 1 to 6 A prepolymer with an average molecular weight of 12,500 was prepared from 4.4'-diphenylmethane diisocyanate and polyethylene adipate glycol using dimethylformamide as a solvent, and the prepolymer was placed in an isophoronediamine solution using dimethylformamide as a solvent. Add to make the concentration 25%
A polyurethane solution was obtained. Dimethylformamide and triethylamine were added to this polyurethane resin solution, and γ-methyl-L-glutamate-N-carboxylic acid anhydride was added thereto and polymerized to obtain a 22% polyurethane-modified amino acid resin solution.

And warp 70 denier, 12 filaments, weft 70
A dyed nylon 6 taffeta product with a denier of 24 filaments, a warp density of 120 threads/inch, and a weft thread density of 90 threads/inch was heat-treated at 180'C after applying 0.07% owf of a fluorine-based water repellent. . Next, the nylon tack treated as described above was coated with a prepared coating solution consisting of a polyurethane-modified amino acid resin solution shown below using a knife-over-roll coater, and immediately an aqueous solution containing 2.5% dimethylformamide by weight was applied. Wet coagulation was performed by immersing the sample in the liquid and retaining it at 25°C for 3 minutes. This coated fabric was washed with hot water at 80'C for 20 minutes, dried, and then added with a fluorine-based water repellent (Dickguard F-70: manufactured by Dainippon Ink Co., Ltd.; active ingredient 20%).
After soaking in 4% by weight emulsion liquid and squeezing with a mangle 1
It was subjected to a heat treatment of 50'CX60 seconds.

[Coating liquid composition] Polyurethane-modified amino acid resin: Polymer solvent described above Nidimethylformamide Polyurethane-modified amino acid resin Concentration: 20% Additive A:
Polyfunctional incyanate 1) Component: cyclic trimer of hexamethylene diisocyanate 2) Addition concentration near, 5% by weight (based on resin purity) Addition amount B:
Water Example 1 2% by weight (based on pure resin) 〃 2 5 〃 (〃 ) 〃 310 〃 (〃 ) 〃 415 〃 (〃 ) Comparative Example 1 4,4'-diphenylmethane diisocyanate and polyethylene in Examples 1 to 4 A polyurethane resin solution containing adipate glycol at a concentration of 25% was applied as a coating liquid to nylon taffeta under the same conditions as in the example, and wet coagulation, hot water washing, drying, and water repellent treatment were performed in the same manner.

The moisture permeability, water resistance, and surface condition of the coated fabric were evaluated and shown in Table 1.

Moisture permeability (moisture permeability: Q/m2・24hr) is JIS-Z0
208, water resistance (water pressure resistance: mmHzO> J l5-L
Measured according to 1079.

In addition, the coating liquid in Examples 1 to 4 described above without adding water and coated, wet coagulated, washed in hot water, dried, and treated with water repellent in the same manner as in Examples 1 to 4 had a water pressure resistance of 200.
It was 0mmH2O, but the moisture permeability was 6'000g/m2.
It was at a low level of 24 hours.

Roughly speaking, in Examples 1 to 4, when water was added to the coating liquid in an amount of 20% by weight based on the pure resin content, the coating liquid gelled, resulting in decreased flowability and a uniform coating could not be achieved.

Table 1 Film thickness Moisture permeability Water pressure resistance (μ) (Q/m2・24hr) (mmHpo
) Example 1 25 8000 2100 2
30 8400 2000〃 3 30 8
600 2000〃 4 35 8600 1
400 Comparative Example 1 40 2600 1500 Examples 5 to 6 4. Dimethylformamide and a polymerization initiator triethyleneamine were added to a 25% polyurethane resin solution containing 4'-diphenylmethane diisocyanate and polyethylene ether glycol, and γ- Methyl
A polyurethane-modified amino acid resin solution having a concentration of 24% was obtained by adding glutamate N-carboxylic acid anhydride and polymerizing it. Next, using the same nylon taffeta as in Examples 1 to 6, this resin solution was subjected to wet coating and water processing in the same manner as in Examples 1 to 6 using the coating solution prepared below.

[Coating liquid composition] Polyurethane-modified amino acid resin: Polymer solvent dimethylformamide Polyurethane-modified amino acid resin concentration: 21% Additive A:
Polyfunctional isocyanate 1) Component; reaction product of hexamethylene diisocyanate with trimethylolpropane 2) Addition concentration (relative to resin purity) Example 5 2.5% by weight 〃 6 5 〃 〃 7 7.5 〃 Addition amount B : Water 5% by weight (based on pure resin content) The moisture permeability, water resistance, adhesive strength, and texture of this coated fabric were evaluated and shown in Table 2.

Moisture permeability and water resistance were measured in the same manner as in Examples 1 to 4, and adhesive strength was measured in accordance with JIS K-6328.

In addition, the amount A added to the coating liquid of Examples 5 to 7 described above was
The moisture permeability of the coating, wet coagulation, drying, and clear water processing without adding polyfunctional isocyanate is 8400C.
]/m2・24hr, water pressure resistance is 1200mmH
The adhesive strength between the nylon taffeta and the coating is as low as 2O, and the adhesive strength between the nylon taffeta and the coating is 12
The coated fabric was 0CI/Cm, which was at a low level that could not be put to practical use.

Table 2 Film thickness Moisture permeability Water pressure resistance Adhesion strength (μ) (mmHpo > (g/cm)
Example 5 35 9000 1800 29
0# 6 30 8700 2100 3
00〃7 30 8400 2000 340
[Effects of the Invention] The present invention has been able to provide a fabric that has excellent texture and feel, compensates for the drawbacks of polyamino acid resin and polyurethane resin, and has waterproofness and high level of moisture permeability.

[Brief explanation of drawings]

Figures 1 and 2 are electron microscope photographs of the surface and cross section of a coated fabric (Example 3) comprising a polyurethane-modified amino acid resin film according to the present invention.
The figure shows the surface portion of the coating at a magnification of 3000 times, and FIG. 2 is a cross-sectional view including nylon taffeta at a magnification of 1500 times. Fig. 3.4 is an enlarged photograph of the coated fabric of the conventional example (Comparative Example 1), in which Fig. 3 is a 3000x magnification of the surface of the coating, and Fig. 4 is a cross section including nylon taffeta, magnified 1500x.

Claims (2)

[Claims] (1) A waterproof fabric characterized in that oblong cavities with a maximum length of 1 to 10 μm and micropores with a maximum length of less than 1 μm are distributed in a mixed manner throughout the coating film made of a polyurethane-modified amino acid resin. (2) The method for producing a waterproof fabric according to claim (1), wherein water is added to the polyurethane-modified amino acid resin at a ratio of 15% or less based on the resin content, and then wet coating is performed.