JPH0379643A - Method for forming w/o type emulsion and cellular substance - Google Patents

Abstract

PURPOSE:To readily obtain a useful cellular film capable of setting pore diameter within a wide range by selecting the ratio of components by blending a polymer with water and amino acid polymer using a specific organic solvent. CONSTITUTION:An aqueous solution of a water-soluble amino acid polymer is emulsified and mixed with a polymer solution or dispersion in an organic solvent having <=150 deg.C boiling point and <=50g solubility in water based on 100g composed of the organic solvent and a polymer. A support is then coated with the resultant emulsion and subsequently dried. SBR, NBR, etc., are used as the polymer and benzene, toluene, etc., are used as the solvent. Polymers of glycine, proline, serine, etc., having 200-3000 molecular weight are used as the amino acid polymer.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to surface forming membranes for leathers such as synthetic leather, artificial leather, and natural leather, various separator membranes, and porous membranes having communicating holes used in the medical field. The present invention relates to a method for forming a microporous membrane (microporous membrane).

[Prior art]

Many methods for producing microporous membranes have been proposed and put into practical use. The methods can be roughly divided into extraction methods, which are typified by wet methods, and drying methods. However, these conventional methods are difficult to control depending on the application due to the control of pore size during thin film formation, slow production speed, etc. The reality is that there are still many points that are unsatisfactory and that although it is necessary, it has not been implemented.

For example, coatings with high air permeability and moisture permeability are desirable from the viewpoint of comfort for surface finishing films on synthetic, artificial, and natural leathers used in clothing, furniture seats, vehicle seats, cowhide shoes, etc. However, a satisfactory method has not yet been implemented.

[Problem to be solved by the invention]

The present invention was made against the background of the above-mentioned problems of the prior art, and is a W10 for forming porous material that can have the effect of making the pore diameter suitable for the function and performance required for each application.
The object of the present invention is to provide a type emulsion and a method of forming a porous structure using the same.

[Means for solving problems]

The present invention involves adding a large amount of water-soluble amino acids to a polymer organic solvent solution or dispersion consisting of a polymer and an organic solvent having a boiling point of 150° C. or less and a water solubility of 50 g or less per 100 g. The present invention provides a W10 type emulsion for porous molding obtained by emulsifying and mixing an aqueous solution of the present invention, and a method for forming a porous structure, which comprises coating a support with the W10 emulsion and then drying it.

In the present invention, an organic solvent having a boiling point of 150° C. or lower and a water solubility of 50 g or lower per 100 g is used. The porosity formation mechanism of the present invention is that when drying the W10 emulsion coated on the support, the organic solvent in the emulsion evaporates faster than the dispersed water, and the polymer absorbs the dispersed water. The boiling point of the organic solvent of the present invention must be 150"C or less, preferably 120"C or less. If an organic solvent with a boiling point exceeding 150"C is used, During drying, the organic solvent constituting the W10 emulsion and the dispersion water evaporate simultaneously, making it impossible to obtain the microporous structure targeted by the present invention. Considering the porosity mechanism of the present invention, the reason why organic solvents having a boiling point of 100°C or higher, which is the boiling point of water, can be used in the present invention is because the water-soluble amino acid polymer used in the present invention is oriented on the surface of the dispersed water. This is thought to be due to the fact that water is dispersed stably and evaporation is delayed even under conditions of rapid drying at high temperatures, because a molecular film is formed.

Further, the W-containing solvent of the present invention must have a water solubility of 50 g or less per 100 g of the organic solvent. If an organic solvent with water solubility exceeding 50 g is used, the polymer will coagulate during the time when the aqueous solution of the amino acid polymer is added to the organic solvent solution of the polymer, making it impossible to obtain a stable emulsion.

Examples of the aqueous solvents of the present invention having a boiling point of 150° C. or lower and a water solubility of 50 g or lower per 100 g include benzene, toluene, xylene, methyl ethyl ketone, diethyl ketone, ethyl butyl ketone, dibutyl ketone, ethyl acetate, and butyl acetate. , ethane dichloride, etc. In some cases, it may be a mixed solvent of an organic solvent with low miscibility with water and an organic solvent with high miscibility with water, such as toluene/tetrahydrofuran, methyl ethyl ketone/tetrahydrofuran, or toluene/dioxane. do not have.

The polymers used in the present invention include natural resins such as natural rubber, polyvinyl chloride, 5BR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), polyurethane, polystyrene, polyamino acids,
Examples include conventionally known synthetic polymers such as polyamide and polyester, and in some cases, mixed polymers thereof may be used.

The polymer organic solvent solution used in the present invention is a polymer organic solvent dispersion solution in which particles of the same type or different type that are insoluble in the organic solvent are dispersed. It doesn't matter if there is. Rather, the presence of such particles reduces the coated 83 W/
When drying the O-type emulsion, it may be preferable because it suppresses shrinkage of the high molecular weight polymer and makes it easier to obtain a porous structure.

Examples of such insoluble particles include conventionally known polymer powders such as penzoquanamine resin powder, silicone powder, polyamino acid powder, polyester powder, and polyamide powder, which are appropriately selected depending on the type of organic solvent used. .

The water-soluble amino acid multimers of the present invention are natural polyamino acid multimers obtained by decomposing proteins such as collagen, or glycine, proline, aspartic acid, serine, alanine, arginine, glutamate, isoleucine, and hydroxyproline. It is a synthetic polymer of amino acids such as , valine, lysine, phenylalanine, leucine, tyrosine, threonine, histidine, methionine, and hydroxylidine. The appropriate molecular weight for forming a stable emulsion is 200 to 3,000, and amino acid polymers with a molecular weight in this range have a strong water retention ability, so when drying the W10 emulsion, the dispersed water does not evaporate. This makes it easier to obtain the microporous structure that is the object of the present invention.

The concentration of the polymer in the organic solvent solution of the polymer used in the present invention can be used in a wide range from high concentration to low concentration. For example, if used at a high concentration, the resulting porous material will tend to have a large pore size and a small number of pores, and if used at a low concentration, the resulting porous material will tend to have a small pore size and a large number of pores. The concentration should be selected depending on the intended use. Furthermore, a factor that greatly influences the pore size is the amount of water added. The larger the ratio of the amount of water added to the solid weight of the polymer, the more
The resulting porous material has a small pore size.

As a general range, the amount of water added is 30 to 600 parts by weight per 100 parts by weight of the solid weight of the polymer. However, this range is not intended to limit the invention.

The amount of amino acid multimer constituting the emulsion can also be selected within a wide range. When the weight of the amino acid multimer added is 15 parts by weight or more based on 100 parts by weight of the solid weight of the polymer, the pore diameter of the resulting porous material hardly changes, and the concentration of the polymer and the amount of added water are as described above. has a large influence on the pore size.

When the amount of amino acid multimer added is less than 15 parts by weight, the pore size of the obtained poly7L substance tends to increase as the amount added decreases, but the concentration of the high molecular weight polymer and the amount of added water are also affected at the same time. receive.

Therefore, the amount of polyamino acid multimer should be determined from the stability of the emulsion. In general, the emulsion can be stabilized by adding the amino acid multimer in a wide range of 0.5 to 150 parts by weight per 100 parts by weight of the solid weight of the polymer, but it is possible to stabilize the emulsion with a long pot life. In order to obtain a solidified emulsion, the added weight is preferably 5 parts by weight or more, more preferably 10 to 80 parts by weight.

As explained above, the present invention is unprecedented in that it is possible to set a wide range of pore sizes by selecting the ratios of the high molecular weight polymer, organic solvent, water, and water-soluble amino acid polymer that make up the emulsion. .

In this way, if a wide range of pore sizes can be set, the balance of ventilation, moisture permeability, and water resistance can be set arbitrarily when obtaining a breathable film, and when obtaining a filter film, the pore size can be set arbitrarily depending on the object. This has the advantage of being configurable.

The emulsion of the present invention is obtained by emulsifying and mixing an aqueous solution of a water-soluble amino acid multimer with an organic solvent solution or dispersion of a high molecular weight polymer. The specific manufacturing method is to prepare an aqueous solution in which a water-soluble amino acid multimer is dissolved at an arbitrary concentration, and then add it little by little into an organic solvent solution or dispersion of a polymer at an arbitrary concentration while stirring. S, W
A common method is to form a /O type emulsion.

The emulsion of the present invention becomes porous when coated on a support such as release paper, polyester film, woven fabric, knitted fabric, nonwoven fabric, synthetic leather, artificial leather, natural leather, etc. and dried. As a method for coating the support, ordinary coating methods such as knife coating, roll coating, and gravure coating can be employed.

In addition, the drying temperature at this time can be applied from room temperature to high temperatures of 150°C or higher, but it is preferable to set the temperature below the softening temperature of the high molecular weight polymer constituting the emulsion, and in order to speed up the drying speed and increase productivity. Preferably, the temperature is as high as possible. Therefore, the drying temperature is i o o'c~1
50°C is generally preferred. For example, if the emulsion is coated on a support in an amount of 100 g/nf and dried, the target porosity can be obtained in about 1 minute at a drying temperature of 120°C. If this dryer is used, the line speed is about 20 m/min and high productivity can be obtained.

The pore formation mechanism of the present invention is based on the following principle. That is, the spherical surface of the dispersed water constituting the emulsion is covered with the water-soluble amino acid polymer, and the emulsion is stabilized by its surfactant effect. In other words, the lipophilic groups are oriented toward the organic solvent solution of the high molecular weight polymer, and the hydrophilic groups are oriented toward the water particles, thereby stabilizing the emulsion and preventing water from flowing even during drying after coating on the support. The particles do not agglomerate, and the polymer coagulates as the organic solvent evaporates. At this time, the evaporation of the dispersed water particles is delayed compared to the evaporation of the aR agent due to the water-retaining effect of the water-soluble aranoic acid polymer covering the surface.

In the emulsion, when using a high molecular weight polymer that shrinks greatly upon evaporation of the organic solvent, the above-mentioned insoluble particles can be used in combination to suppress the shrinkage and effectively provide a porous structure.

The porous material obtained by the above method is peeled from the support,
It can be widely used as various separator membranes, gas permeable membranes in the medical field, water-resistant gas permeable membranes in the medical field when used in combination with water repellent treatment, decorative gas permeable coatings on synthetic leather, artificial leather, natural leather, etc. In addition, fiber aggregates such as woven fabrics, knitted fabrics, and non-woven fabrics that are directly coated are also used as waterproof breathable fabrics for medical, medical, and other purposes.
It can be used in many fields such as clothing.

〔Example〕

Hereinafter, the present invention will be specifically explained in detail with reference to Examples. Note that "parts" and "%" in the examples are based on weight, and the measured characteristic values were obtained by the following method.

(a) Air permeability A value measured using a Gurley densometer according to the method of JIS P8117, expressed as the time (seconds) required for 50 mfl of air to pass through.

(b) Moisture permeability It is expressed in water vapor permeability (g/day) according to JIS L1099 A-1 method.

(c) Water pressure resistance According to JIS L1092 A method, water pressure resistance is expressed in water columns (Inm).

Example 1 (Preparation of W/O emulsion) 15 of polyurethane-polyvinyl chloride copolymer (manufactured by Toagosei Kagaku ■)
% methyl ethyl ketone/toluene (weight ratio) = 60/4
70 parts of a 10% aqueous solution of polyglutamic acid having a molecular weight of 800 was added to 10 parts of the 0 solution with stirring to obtain a W/O emulsion.

Example 2 (Preparation of W10 type emuldigon) An 8% ethylene dichloride solution of a polymer mainly composed of polyamino acids (
Seiko Kasei ■, Luxkin XB-900) 10
To 0 parts, 50 parts of a 10% aqueous solution of a water-soluble polyamino acid polymer (manufactured by Sumitomo Chemical Co., Ltd., Highmarsh) was added with stirring to obtain W10 type emuldigon.

Example 3 (Preparation of W10 type emuldigon) 15% polyurethane-methyl ethyl ketone/toluene (70/30
) To 100 parts of the solution, 25 parts of a 10% aqueous solution of a water-soluble polyamino acid polymer (Himarsh, manufactured by Sumitomo Chemical Co., Ltd.) was added with stirring to obtain a W10 type emulsion.

Example 4 (Formation of porous structure) 100% of the emulsion obtained in Example 1 was placed on release paper.
It was coated with a size of 04 g/rri, and immediately after drying at 110°C for 30 seconds, a knitted fabric made of polyester fibers was attached and further dried at 120°C for 2 minutes. Thereafter, the release paper was peeled off to obtain a sheet-like porous coated knitted fabric.

The sheet-like porous coated knitted fabric obtained by the water repellent treatment was breathable, moisture permeable, and water resistant, making it ideal for use as water resistant and cold protection clothing.

Example 5 (Formation of porous structure) A liquid obtained by mixing the emulsion obtained in Example 1 with a colored pigment was applied to the surface of an unfinished artificial leather substrate having a porous surface made of polyurethane and having a foOg/rd of 04 Coated in size and dried at 120° C. for 1 minute. The obtained sheet-like colored artificial leather had breathability and was comfortable for use as biocidal leather, clothing, gloves, furniture and vehicle seats, etc.

Example 6 (Formation of porous structure) 110 meshes of the liquid obtained by mixing the emulsion obtained in Example 2 with a colored pigment were applied to the surface of the unfinished artificial leather substrate used in Example 5, which had a polyurethane porous surface. It was applied using a gravure roll and dried at 110°C for 20 seconds. The obtained sheet-like colored artificial leather had high air permeability and moisture permeability, and was comfortable for use in shoes, clothing, and furniture and vehicle seats.

Example 7 (Formation of porous structure) The emulsion obtained in Example 3 was coated on a polyester film in a 54-dimensional amount of 150 g/rd.
It was dried at 10°C for 2 minutes. The sheet-like porous membrane obtained by peeling from the polyester film after water-repellent treatment is breathable and has an apparent density of 0.32 g/c+11, making it useful as various separator membranes and medical membranes. Met.

Example 8 (Formation of porous structure) 100% of the emulsion obtained in Example 2 was placed on release paper.
g/rd (coated in 1 quantity, 4 at 110"C)
After drying for 0 seconds, it was then coated with a two-component type polyurethane adhesive solution at a basis weight of 150 g/rrf and dried at 120°C for 40 seconds, and then a knitted fabric made of polyester fiber was impregnated with a polyurethane-dimethylformamide solution. The coated and wet-coagulated substrates were bonded together and left at 50° C. for 3 days. The sheet-like artificial leather obtained by peeling off the release paper has a porous surface made of polyamino acid resin, so it has excellent sweat absorption and moisture release properties, is free from stickiness, and has the fine appearance of natural leather. It was useful as a furniture seat and a vehicle seat.

Comparative Example 1 On a release paper, 1 part of a nonionic surfactant having a polyoxyethylene segment (manufactured by Toray Silicone ■, SH28PA) was added to 100 parts of a 15% polyurethane-methyl ethyl ketone/toluene (70/30) solution. Thereafter, 30 parts of water was added while stirring to coat W10 type emulzidine in a 54-dimensional amount of 100 g/nf, and the film was dried at 110"C for 2 minutes. The film obtained by peeling from the release paper was not porous and had no air permeability.

Table 1 shows the properties of the porous sheet materials obtained in Examples 4 to 8 and Comparative Example 1.

(Leaving space below) Table 1 [Effects of the Invention] The present invention uses - dry laminating equipment and - dry gravure coating equipment to achieve air permeability, which cannot be obtained with conventional methods, at the same drying speed as conventional methods. This is a method of forming a porous material with excellent moisture permeability, air permeability and water resistance, and moisture permeability and water resistance. It can be effectively used in a wide range of applications such as the medical field.

[Brief explanation of drawings]

Figure 1 is an electron micrograph of the surface (particle structure) of the porous IT-coated coating obtained in Example 4, and Figure 2 is the surface (particle structure) of the colored artificial leather obtained in Example 5. 3 is an electron micrograph of the surface (particle structure) of the colored artificial leather obtained in Example 6, and FIG. 4 is an electron micrograph of the surface (particle structure) of the porous membrane obtained in Example 7. Figure 5 is an electron micrograph of the surface (particle structure) of the artificial leather obtained in Example 8, and Figure 6 is the surface (particle structure) of the film obtained in Comparative Example 1. Electron micrographs of each are shown. The magnification of each electron micrograph is 50
It is 0 times.

Claims (2)

[Claims] (1) Boiling point is 150℃ or less and water solubility is 1
A W/O emulsion obtained by emulsifying and mixing an aqueous solution of a water-soluble amino acid multimer into an organic solvent solution or dispersion of a polymer, which is composed of an organic solvent and a polymer in an amount of 50 g or less per 00 g. (2) A method for forming a porous structure, which comprises coating a support with the W/O emulsion according to claim 1 and then drying it.