JPH0618921B2 - Method for forming W / O type emulsion and porosity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a surface forming film of leather such as synthetic leather, artificial leather, and natural leather, various separator films, and a porous material having communicating holes used in the medical field and the like. The present invention relates to a method for forming a quality (microporous film).

[Prior art]

As a method for producing a microporous membrane, many methods have been conventionally proposed and put into practical use. The methods are roughly classified into an extraction method and a drying method, which are typified by a wet method. However, in these conventional methods, it is possible to control the size of pores when forming a thin film, and the production speed is slow. There are still many unsatisfied points, and the reality is that they have not been implemented although they are necessary.

For example, the surface finishing film of synthetic leather, artificial leather, natural leather, and other leather used for clothing, furniture seats, vehicle seats, shoe uppers, etc., has a film that is highly breathable and breathable in terms of comfort. Although desired, there is still no satisfactory method and it is not implemented.

[Problems to be Solved by the Invention]

The present invention has been made against the background of the above-mentioned problems of the prior art, and W / for forming a porous material, which has an effect that a pore diameter suitable for a function or performance required for each application can be obtained
It is an object of the present invention to provide an O-type emulsion and a method for forming a porosity using the same.

[Means for solving problems]

The present invention provides a high-molecular polymer organic solvent solution or dispersion comprising a high-molecular polymer and an organic solvent having a boiling point of 150 ° C. or lower and a water solubility of 50 g or lower per 100 g, and containing a large amount of a water-soluble amino acid. It is intended to provide a W / O type emulsion for porous molding, which is obtained by emulsifying and mixing an aqueous solution of a body, and a method for forming a porous body, which comprises coating the support with the W / O type emulsion and then drying.

In the present invention, an organic solvent having a boiling point of 150 ° C. or less and a water solubility of 50 g or less per 100 g is used. The mechanism for forming the porosity of the present invention is that when the W / O type emulsion coated on the support is dried, the organic solvent in the emulsion evaporates faster than the dispersed water to disperse the high molecular weight polymer. This is because water solidifies in a stable state, and therefore the boiling point of the organic solvent of the present invention must be 150 ° C or lower, preferably 120 ° C or lower. When an organic solvent having a boiling point of more than 150 ° C. is used, the evaporation of the organic solvent constituting the W / O type emulsion and the dispersion water simultaneously proceed during drying, so that the target microporous material of the present invention can be obtained. Absent. The reason why the organic solvent having a boiling point of 100 ° C. or more, which is the boiling point of water, can be used in the present invention in view of the porosity mechanism of the present invention is that the water-soluble amino acid multimer used in the present invention is oriented on the surface of dispersed water. It is considered that the dispersion of water is stable and the evaporation is delayed even under the rapid drying condition at high temperature because the molecular coating is formed.

Further, the organic solvent of the present invention must have a water solubility of 50 g or less per 100 g of the organic solvent. When an organic solvent having a water solubility of more than 50 g is used, when the aqueous solution of the amino acid polymer is added to the high molecular polymer organic solvent solution, the high molecular polymer coagulates and a stable emulsion cannot be obtained.

As the organic solvent 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, benzene, toluene, xylene, methyl ethyl ketone, diethyl ketone, ethyl butyl ketone, dibutyl ketone, ethyl acetate, butyl acetate, There is ethane dichloride, etc., and in some cases, it may be a mixed solvent of an organic solvent having a low miscibility with water and an organic solvent having a high miscibility with water, such as toluene / tetrahydrofuran, methyl ethyl ketone / tetrahydrofuran, and toluene / dioxane. .

The high molecular weight polymer used in the present invention includes natural resins such as natural rubber, polyvinyl chloride, SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), polyurethane, polystyrene, polyamino acid,
Conventionally known synthetic high molecular weight polymers such as polyamide and polyester may be mentioned, and in some cases, a mixed polymer thereof may be used.

The high molecular polymer organic solvent solution used in the present invention is a high molecular polymer organic solvent dispersion solution in which the same kind or different kinds of particles insoluble in the organic solvent are dispersed in the high molecular polymer organic solvent solution. It doesn't matter. Rather, the presence of such particles is preferred in some cases, since the shrinkage of the high molecular weight polymer is suppressed and the porosity is easily obtained when the coated W / O type emulsion is dried.

Examples of such insoluble particles include conventionally known polymer powders such as benzoquanamine 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 multimer of the present invention is a protein, for example, a natural polyamino acid multimer obtained by degrading collagen or the like, or glycine, proline, aspartic acid, serine, alanine, arginine, glutamic acid, isoleucine, hydroxyproline, valine, It is a synthetic multimer of amino acids such as lysine, phenylalanine, leucine, tyrosine, threonine, histidine, methionine, and hydrokyridine. A suitable molecular weight for forming a stable emulsion is 200 to 3,000, and an amino acid multimer having a molecular weight in this range has a strong water retention property. It is easy to obtain the microporous material that is the object of the present invention by delaying the evaporation of.

The concentration of the high molecular polymer in the high molecular polymer organic solvent solution used in the present invention can be used in a wide range from high concentration to low concentration. For example, when used at a high concentration, the resulting porous material tends to have a large pore size and a small number, and when used at a low concentration, the resulting porous material tends to have a small pore size and a large number, and thus the purpose is The concentration should be selected according to the intended use. Further, the factor that greatly affects 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 high molecular weight polymer,
The resulting porous material has a small pore size.

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

The amount of the amino acid multimer constituting the emulsion can be selected within a wide range. When the added weight of the amino acid multimer is 15 parts by weight or more based on 100 parts by weight of the high molecular weight polymer solid, the pore size of the obtained porous material hardly changes, and the concentration of the high molecular weight polymer and the amount of the added water described above. Greatly affects the pore size.

If the amount of the amino acid polymer added is less than 15 parts by weight, the pore size of the porous material obtained tends to increase as the amount added decreases, but the concentration of the polymer and the amount of added water are also affected. .

Therefore, the amount of polyamino acid multimer should be determined from the stability of the emulsion. Generally, the addition weight of the amino acid multimer to 100 parts by weight of the high molecular weight polymer is 0.5 to 150 parts by weight, and the emulsion can be stabilized in a wide range, but it is stable for a long pot life. In order to obtain such an emulsion, the added weight is preferably 5 parts by weight or more, more preferably 10 to 80 parts by weight.

As described above, the present invention does not exist in the prior art in which a wide range of pore diameters can be set by selecting the ratio of a high molecular polymer, an organic solvent, water, and a water-soluble amino acid multimer constituting an emulsion. .

In this way, if a wide range of pore diameters can be set, in the case of obtaining a breathable coating, the balance of ventilation, moisture permeability, and water resistance can be set arbitrarily, and in the case of obtaining a coating for a filter, the pore diameter can be arbitrarily set depending on the target substance. The effect that it can be set is obtained.

The emulsion of the present invention can be obtained by emulsifying and mixing an aqueous solution of a water-soluble amino acid multimer with an organic solvent solution or dispersion of a polymer. As a specific production method, a water-soluble amino acid multimer and an aqueous solution dissolved at an arbitrary concentration are prepared in advance, and this is added little by little to a high-molecular polymer organic solvent solution of an arbitrary concentration or a dispersion while stirring. ,
A general method is to form a W / O type emulsion.

When the emulsion of the present invention is coated on a support such as release paper, polyester film, woven fabric, knitted fabric, non-woven fabric, synthetic leather, artificial leather, natural leather, etc. and dried, it is porous. As a method for coating the support, a usual coating method such as knife coating, roll coating, and gravure coating can be adopted.

Further, the drying temperature at this time can be applied from room temperature to a high temperature of 150 ° C. or higher, but a temperature not higher than the softening temperature of the polymer constituting the emulsion is preferable, and in order to accelerate the drying speed and improve productivity. The highest temperature possible is preferable. Therefore, a drying temperature of 100 ° C. to 150 ° C. is generally preferable. For example, when the emulsion is coated on the support in an amount of 100 g / m ² and dried, 12
Since a target porosity can be obtained in about 1 minute at a drying temperature of 0 ° C., a general dryer having a length of 20 m can achieve high productivity with a line speed of about 20 m / min.

The porosity forming mechanism of the present invention is based on the following principle. That is, the spherical surface of the dispersed water that constitutes the emulsion is covered with the water-soluble amino acid multimer, and the emulsion is stabilized by the surface-active effect. That is, the lipophilic group is oriented to the high molecular weight polymer organic solvent solution side,
By orienting the hydrophilic groups on the water particle side, the emulsion is stabilized, the water particles do not agglomerate during drying after coating on the support, and the water-soluble polymer of the high molecular weight polymer evaporates as the organic solvent evaporates. Coagulation occurs. At this time, the water dispersion particles have a water-retaining effect due to the water-soluble amino acid multimers covering the surfaces thereof, so that the evaporation is delayed as compared with the evaporation of the organic solvent. In the emulsion, when a high-molecular polymer having a large shrinkage upon evaporation of an organic solvent is used, the use of the above-mentioned insoluble particles together suppresses the shrinkage, and it is easy to effectively obtain a porous structure.

The porous obtained by the above method is peeled from the support,
It can be widely used as various separator membranes, breathable membranes in the medical field, water-resistant breathable membranes in the medical field, surface makeup breathable coatings for synthetic leather, artificial leather, natural leather, etc. In addition, those that are coated directly on fiber aggregates such as woven fabric, knitted fabric, and non-woven fabric can also be used as medical ventilation, etc.
It can be used in many fields such as clothing.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to specific examples. In the examples, "parts" and "%" are based on weight, and the characteristic measurement values were obtained by the following methods.

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

(B) Moisture permeability According to the method of JIS L1099 A-1, it is expressed by moisture permeability (g / m ² · day).

(C) Water pressure resistance According to the method of JIS L1092 A method, the water pressure resistance is expressed by a water column (mm).

Example 1 (Production of W / O type emulsion) 100 parts of a 15% methyl ethyl ketone / toluene (weight ratio) = 60/40 solution of a polyurethane-polyvinyl chloride copolymer (manufactured by Toagosei Kagaku Co., Ltd.) in 100 parts of a molecular weight of 800 70 parts of a 10% aqueous solution of polyglutamic acid was added with stirring to obtain a W / O type emulsion.

Example 2 (Preparation of W / O type emulsion) 8% ethylene dichloride solution of a polymer mainly composed of polyamino acid (manufactured by Seiko Kasei Co., Ltd., Luck Skin XB)
-900) 100 parts of a 10% aqueous solution of a water-soluble polyamino acid multimer (Sumitomo Chemical Co., Ltd., Hiimage) 5
0 part was added with stirring to obtain a W / O type emulsion.

Example 3 (Preparation of W / O type emulsion) A 100% solution of a 15% polyurethane-methylethylketone / toluene (70/30) solution was added to a 10% aqueous solution of a water-soluble polyamino acid multimer (Sumitomo Chemical Co., Ltd., Hiimage). 25 parts were added with stirring to obtain a W / O type emulsion.

Example 4 (Formation of Porous Material) 100 μm of the emulsion obtained in Example 1 was placed on a release paper.
Coating was carried out at a basis weight of g / m ² , and immediately after drying at 110 ° C. for 30 seconds, a knitted fabric made of polyester fibers was bonded and further dried at 120 ° C. for 2 minutes. Then, the release paper was peeled off to obtain a sheet-like porous coated knit.

The sheet-like porous coated knitted fabric obtained by the water-repellent treatment has breathability, moisture permeability, and water resistance, and is optimal as a water-resistant cold-wearing garment.

Example 5 (Formation of Porosity) 100 g / m ² of a liquid prepared by mixing the emulsion obtained in Example 1 with a color pigment was applied to the surface of a breathable artificial leather unfinished substrate having a polyurethane porous surface. The coating was carried out at a basis weight and dried at 120 ° C. for 1 minute. The obtained sheet-like colored artificial leather was breathable and was comfortable for shoe uppers, clothing, gloves, furniture vehicle seats, and the like.

Example 6 (Formation of Porous Material) On the surface of the unfinished artificial leather substrate used in Example 5 whose surface is made of polyurethane porous material, a liquid obtained by mixing the emulsion obtained in Example 2 with a color pigment is used to form a 110 mesh liquid. It was applied using a gravure roll and dried at 110 ° C. for 20 seconds. The obtained sheet-like colored artificial leather was highly breathable and breathable, and was comfortable for shoes, clothing, and furniture vehicle seats.

Example 7 (Formation of Porosity) A polyester film was coated with the emulsion obtained in Example 3 at a basis weight of 150 g / m ² , and 110
It was dried at 0 ° C for 2 minutes. The sheet-like porous film obtained by peeling from the polyester film after water repellent treatment has air permeability and an apparent density of 0.32 g / cm ³ and is useful as various separator films and medical films. there were.

Example 8 (Formation of Porous Material) 100 μm of the emulsion obtained in Example 2 was placed on a release paper.
After coating with a basis weight of g / m ² and drying at 110 ° C for 40 seconds, then a two-component type polyurethane adhesive solution is coated with a basis weight of 150 g / m ² and 120 ° C.
After drying for 40 seconds, a knitted fabric made of polyester fiber was impregnated with a polyurethane-dimethylformamide solution, coated and wet-coagulated on the substrate, and the substrate was left at 50 ° C. for 3 days. The sheet-shaped artificial leather obtained by peeling off the release paper has a surface formed by the porosity of the polyamino acid resin, so it has excellent sweat absorption, moisture release, etc., is not sticky, and has a natural-looking appearance of natural leather. It has a usefulness as a furniture seat and a vehicle seat.

Comparative Example 1 1 part of a nonionic surfactant (SH28PA manufactured by Toray Silicone Co., Ltd.) having a polyoxyethylene segment in 100 parts of a 15% polyurethane-methyl ethyl ketone / toluene (70/30) solution on release paper. After addition, 30 parts of water was added with stirring to obtain W / O
The type emulsion was coated at a basis weight of 100 g / m ² and dried at 110 ° C. for 2 minutes. The film obtained by peeling from the release paper was not porous and was not breathable.

The characteristics of the porous sheet materials obtained in Examples 4 to 8 and Comparative Example 1 are shown in Table 1.

[Advantages of the Invention] The present invention uses a general dry laminating apparatus and a general gravure coating apparatus at the same drying speed as the conventional one, and has breathability, moisture permeability or ventilation / water resistance, which is not obtained by the conventional method. It is a method of forming a porous material with excellent wet and water resistance, and the obtained porous material is effective for a wide range of applications such as surface forming films of synthetic leather, artificial leather, natural leather, various separator films, medical fields, etc. It can be used.

[Brief description of drawings]

1 is an electron micrograph of the surface (particle structure) of the porous coated knitted fabric obtained in Example 4, and FIG. 2 is an electron of the surface (particle structure) of the colored artificial leather obtained in Example 5. Micrograph, FIG. 3 is an electron micrograph of the surface (particle structure) of the colored artificial leather obtained in Example 6, and FIG. 4 is Example 7.
An electron micrograph of the surface (particle structure) of the porous film obtained in Example 5, FIG. 5 is an electron micrograph of the surface (particle structure) of the artificial leather obtained in Example 8, and FIG. 6 is Comparative Example 1. The electron micrographs of the surface (particle structure) of the film obtained in 1. are shown respectively. The electron micrographs have a magnification of 500 times, respectively.

Claims (2)

[Claims] 1. A water-soluble amino acid in a polymer polymer organic solvent solution or dispersion, which comprises 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. A W / O type emulsion obtained by emulsifying and mixing an aqueous solution of a multimer. 2. A method for forming a porous structure, which comprises coating a support with the W / O type emulsion according to claim 1 and then drying the support.