JPS5945335A - Preparation of porous sheet substance having low water absorption ratio - Google Patents

Abstract

PURPOSE:To prepare a porous sheet useful for simulated synthetic leather substitute, preventing water penetration without damaging permeability and water vapor transmission, by adding an urethane oligomer containing a specific perfluoroalkyl group to a solution of a polyurethane elastomer-containing resin. CONSTITUTION:A solution of a resin comprising polyurethane elastomer as an essential component is blended with 1-10wt% based on the elastomer of urethane oligomer [e.g., compound shown by the formula Rf-X-OH (Rf is 6-12C perfluoroalkyl; X is 1-6C alkylene, arylene, etc.] containing a perfluoroalkyl group having compatibility with the elastomer or miscibility with the solvent for the resin, the solution with the solvent is applied to a substrate, or impregnated into it, the substrate is treated with a liquid substance and/or its vapor having affinity for the solvent but not for the elastomer, to prepare a porous sheet material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a new and useful porous sheet-like material, and more particularly, it relates to a method for producing a new and useful porous sheet-like material, and more particularly, it relates to a method for producing a porous sheet-like material that is novel and useful, and more particularly, it relates to a method for producing a porous sheet-like material that is novel and useful. The present invention relates to a method for producing a porous sheet-like material having a unique feature of low water absorption, which comprises containing a specific perfluoroalkyl group-containing urethane oligomer that has excellent miscibility with a resin solution.

i'g, a resin whose main component is polyurethane elastomer
Applying or impregnating a substrate with the S solution, and then treating the substrate with a liquid, such as water, or its vapor, which has no affinity with the elastomer but has an affinity with the solvent, to extract the solvent. The technique of forming a sheet-like material having a fine continuous porous structure by
The structure, which is a sheet-like material obtained by such a method, inevitably has the function or characteristic of breathability and moisture permeability due to the countless continuous micropores formed therein. So-called artificial leather is widely used as a substitute for natural ridges, as it has the same effect as natural leather in allowing sweat to evaporate and dissipate instantly, even when worn as shoe pegs or clothing. has been done.

However, people who have such a continuous porous structure: The advantages of leather or its processed products, such as breathability and moisture permeability, when used or worn.
However, this characteristic also becomes a major drawback, especially when the target is exposed to water for a long period of time, such as during rain. However, it has become infiltrated, and as a result, it has become impossible to use it for a long time or gradually perform JfJ, so it has been used with very basic and serious defects.

Therefore, as a method to overcome these drawbacks, a method has been proposed in which a film prepared by a dry method is laminated on the porous sheet having the function of air permeability or moisture permeability, and this method has been widely used. Even with such improved methods, this laminated non-porous film still remains in contact with water for extended periods of time.
While there is no external moisture phenomenon caused by water infiltration, the original characteristic functions such as breathability or moisture permeability are significantly reduced, and the internal The current drawback is that the sweat generated from the fabric does not evaporate at all, rather the internal wettability increases significantly, leading to amplified discomfort when worn. remains unresolved.

However, the inventors of the present invention sought to eliminate all of these drawbacks in the prior art (as a result of our earnest efforts, we discovered that in a solvent solution of a resin containing polyurethane elastomer as an essential component,
By containing a specific perfluoroalkyl group-containing urethane oligomer that is highly compatible with the resin component or has excellent miscibility with the resin solution, the resin can be used without impairing the air permeability or moisture permeability, which is the inherent functional property of the resin. It was discovered that a useful porous sheet-like material having extremely low water absorption capacity could be obtained, and the present invention (C1) was completed.

That is, the present invention involves applying or impregnating a substrate with a solvent solution of a resin containing a polyurethane elastomer as an essential component, and then applying a liquid substance that has an affinity for the solvent but not for the elastomer. and/i) A method for producing a sheet-like material having a fine continuous porous structure by treating the liquid material with vapor, wherein the resin F4 liquid contains 1 to 10
% of a perfluoroalkyl group-containing urethane oligomer having excellent compatibility with the elastomer or with the resin TD liquid. This is what we provide.

Here, as the polyurethane elastomer, known and commonly used ones can be used, but linear polyurethane or polyureaurethane is particularly suitable, and typical examples of such linear polyurethane or polyureaurethane are:
Polyester with hydroxyl groups at both ends of the molecule and a number average molecular weight (Mn) of 400 to 5.000! A substantially linear polyurethane or polyureaurethane obtained from bamboo polyether, an organic diisocyanate, and a chain extender having two active hydrogens in the molecule, and is a typical example of such a chain extender. These include ethylene glycol, butylene glycol, hexamethylene glycol, ethylene diamine, propylene diamine, hexamethylene diamine, diaminodiphenylmethane, piperazine, hydrazine or water.

Polyvinyl chloride, polymethyl methacrylate, acrylonitrile-styrene, etc. may be added to the polyurethane or polyurea urethane as long as it does not impair the texture of the sheet-like material obtained or impair the KW performance. (i)
There is no problem in using a mixture of 911 and other various polymers such as A4 fat and dissolved therein.

Then, as a solvent for the polyurethane elastomer, 2
Typical examples include dimethylformamide, dioxane or acetone, dimethylformamide, diethylacetamide or tetrahydrofuran.
Among these, dimethylformamide, dioxane and acetone are particularly preferred, and it is a matter of course that a mixed solvent containing these as main solvents with other solvents can also be used.

Further, in carrying out the method of the present invention, the above-mentioned substrate and [~
Typical examples include fibrous substrates such as woven, knitted or non-woven fabrics made of various natural or synthetic fibers; various films made of synthetic resins such as polyester; metal plates and glass plates.

Furthermore, the coagulation bath used in implementing the method of the present invention is a non-solvent for the polyurethane distomer described above, but has an affinity (miscibility) with the solvent for the elastomer described above. ), the most common being water.

The coagulation bath may contain a solvent for the elastomer in an amount of 30-j, lj or more of the bath solvent.

On the other hand, the perfluoroalkyl group-containing urethane oligomer used in carrying out the method of the present invention is as described above (i.e., it is compatible with the polyurethane elastomer or the elastomer is an essential component). (It is a synonym for a substance that has excellent mixed phase with a fat-resistant solvent solution.
OH/ NC0=0.7
A typical example is one obtained by reacting at an equivalent ratio of /1.0 to 1.0/1.0, but those with Mn of 1.500 or more have the effect of significantly lowering the water absorption capacity. 2. is more preferable, especially 2. ODD~7. Preferably, Mn is OOO.

Rf -X-OH[I'1 Here, typical compounds as the above compound 4m&) include C
6F13C) 12cH20H, C3F17CH2CH2
0H1C8F, 7So2N(CH2CH20H)2, 1
There is L.

In the urethane oligomer, the incyanate compound to be reacted with the compound (λ) as described in item IJ is, for example, a perfluorinated compound obtained by reacting a 1-shaped compound having an isocyanurate ring. Alkyl Fund:
The f4 urethane oligomer is preferably 1 because it has almost no effect on reducing water absorption capacity, and -Mn is 1.50.
When using a urethane oligomer containing a co-alkyl group, the burn mouth is less than 0. When using a urethane oligomer containing an alkyl group, the solubility with the polyurethane elastomer is poor, and the miscibility with the solvent solution of the resin containing the A+J distomer as an essential component is poor. 1- Becoming L
7. Moreover, bleeding from the obtained porous sheet-like material is also likely to occur (therefore, durability such as washing resistance is also poor, which is not preferable; 7. Perfluoroalkyl group having Mn exceeding OOO When using urethane oligomers containing urethane oligomers, they have excellent compatibility or miscibility, and are also excellent in durability, but as the molecular weight increases, the content of perfluoroalkyl groups decreases, resulting in a decrease in water absorption capacity. The effect of
Although it is preferable, it is ugly.

Therefore, in carrying out the method of the present invention, the addition of the perfluoroalkyl group-containing urethane oligomer to the solvent solution of the resin containing the polyurethane elastomer as an essential component is a step of preparing the polyurethane elastomer. This can be carried out at any stage, and after the preparation of the elastomer, C
What is okay to do is a passionate argument.

The addition amount of the bar 70 loalkyl group-containing urethane oligomer is MM of the polyurethane elastomer.
1 to 10%, 1 to 5% cape based on I,
A concave circle is appropriate. If the amount added exceeds 10% and is frequently used, wet film forming properties will be inhibited and should be avoided.

In addition, the solvent solution of the resin containing the above-mentioned polyurethane elastomer as an essential component contains coagulation regulators, pigments, dyes, fillers, thickeners, ultraviolet absorbers (ultraviolet stabilizers),
Various known additives for f,N such as defoamers or antistatic agents may also be added.

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples, where all parts and percentages are based on weight unless otherwise specified.

In each of the Examples and Comparative Examples, the perfluoroalkyl group-containing urethane oligomer that was prepared in pieces was treated with an incyanate compound and the above-mentioned general formula CI) under the conditions listed in Table 1. 50% by weight obtained by reacting the compound starch with al in dimethylformamide
It is provided in a solution with varying concentrations.

Examples 1 to 6 and Comparative Examples 1 to 3 Polyethylene adipate with Mn of 2,000 having hydroxyl groups at both ends, diphenylmethane-4,4'-diisocyanate and ethylene glycol in a ratio of 1:4:3
Perfluoroalkyl group-containing urethane oligomers obtained in Reference Examples 1.2.5 and 6 were compared to a 20% dimethylformamide solution (viscosity at 25°C of −300 voids) of a polyurethane elastomer obtained by reacting the polyurethane elastomer at a molar ratio of A, B, E and F were added and contained in the proportions shown in Table 2 to obtain a preparation.

Next, a polyester nonwoven fabric with a thickness of 0.7 mm was immersed in each of these preparations to thoroughly fill the inside, and then
Niragol with a clearance of 1.0 was passed through it and then immersed in a coagulation bath of water at 20° C. for 5 minutes. After that, wash it with warm water at 50℃ for 30 minutes and then
It was dried with hot air at ℃ for 10 minutes.

The results of each performance test for each porous sheet-like material t4 obtained in this manner are those of JI Loli shown in the same table.

As is clear from the results shown in Table 2, none of the products of the present invention impairs the functional properties of breathability and moisture permeability, and moreover, the water absorption rate is significantly reduced by 20% or less. effect has been expressed.

On the other hand, when the perfluoroalkyl group-containing urethane oligomer is not contained (Comparative Example 1) and when the perfluoroalkyl group-containing adduct polyurethane made from a cyclic polyisocyanate compound is contained (Comparative Example 2), In all cases, the effect of reducing the water absorption rate was completely observed, and the porous sheet-like material was completely moistened to the inside, especially in the case of Comparative Example 2, which was almost the same as in each of the above-mentioned Examples. Considering that it has the same water pressure resistance, it seems to be waterproof, but it absorbs water in a state that closely resembles that of being in contact with water for a long time. A clear difference in effectiveness was observed in the rate test.

In addition, when 15% of the perfluoroalkyl group-containing urethane oligomer was added to the polyurethane disstomer as in Comparative Example 3, a porous sheet material with low water absorption capacity was formed. However, this sheet-like material 1J has poor film-forming properties, so it can be said that it is extremely poor in industrial practicality.

Examples 4 to 6 and Comparative Examples 4 to 6 A) Boriogysitetetramethylene glycol having Mn of 2,0O07,c and having hydroxyl groups at both ends, diphenylmethane-4,4'-diisocyanate, and ethylene glycol were :20% dimedylpornoamide solution of polyurethane elastomer obtained by reacting at a molar ratio of 5:4 (viscosity at 25°C -300 voids),
Reference example: Perthmiroargyl foundation I1 urethane oligomers C, D, G and I obtained in 4.7.8 and 9
I and perfluoroargyl group-containing adduct polyurethane I were added in the proportions shown in Table 6 to obtain a formulation.

Next, each of these preparations was spread over 0.2 m of nylon taffeta with 210 fibers each having a thickness of 70 denier.
After applying the film to a film thickness of m and leaving it in an atmosphere of 40°C and 90% RH, it was coated in a coagulation bath of water at 20°C for 5 m.
It was soaked for a minute.

Hereinafter, the results of various performance tests for each porous sheet-like material obtained in the same manner as in Example 1 will be described, as is clear from the results shown in Table 3 shown in the same table. All of the products have a remarkable effect of reducing water absorption, while the comparative products show no such effect at all (i.e., the porous sheet material is completely moistened to the inside). It had been.

Claims (1)

[Claims] A substrate is coated with or impregnated with a solvent solution of a resin containing a polyurethane elastomer as an essential component, and then this substrate is coated with a liquid substance that has an affinity for the solvent but not for the elastomer and/or the liquid substance. In a method for producing a sheet-like material having a fine continuous porous structure by treating the material with vapor, the resin solution contains 1 to 10% of the elastomer's compatibility or compatibility with the elastomer. A method for producing a porous sheet-like material with a low water absorption rate, which comprises containing a urethane oligomer containing a per-70-roalkyl group that has excellent mixed phase with a resin solution.