JPH0586979B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a polyvinyl acetal porous body having antifungal or bactericidal properties. (Conventional technology) Polyvinyl acetal porous materials have good breathability,
Because it has cushioning properties, cushioning properties, water absorption properties, etc.
Taking advantage of its characteristics, it is widely used in a variety of applications, such as puffs for water-based makeup. Polyvinyl acetal porous materials harden when dry and lose their flexibility and elasticity, so they are generally used in a wet state. For this reason, they are often stored in a humid state, and when they are stored in a humid state, there is a problem in that mold is likely to form. The generation of mold is extremely problematic in terms of hygiene, appearance, and handling, and it is desired to impart mold-proofing properties, bactericidal properties, etc. to polyvinyl acetal-based porous materials by some method. Attempts have been made for a long time to impart specific functions to various porous bodies such as polyvinyl acetal porous bodies. For example, a method is known in which fine particle powder having a specific function is fixed to a porous body to impart the functional characteristics of the fine particle powder. Such methods include a method in which fine particle powder is added to the raw solution during production of the porous body, and the fine particle powder is incorporated and fixed in the porous body, or a method in which fine particle powder is added to the external surface of a separately manufactured porous body. There are methods of fixing the material to the surface of the porous body by means such as adhesion or fusion. Therefore, in order to impart mold-proofing and sterilizing properties to polyvinyl acetal-based porous bodies, the above-mentioned method is used, namely, fine particle powder having mildew-proofing properties, sterilizing properties, etc. is dispersed and fixed in polyvinyl acetal-based porous bodies. It is possible that However, in the method of adding and blending fine-particle powder to the production stock solution, the fine-particle powder is exposed to the action of the reaction system raw materials, solvents, and catalysts contained in the stock solution, as well as to harsh reaction conditions and atmospheres such as heating. may be decomposed or undergo chemical changes, resulting in loss of its original functions and characteristics. Furthermore, it is difficult to obtain a porous body in which fine particle powder is evenly dispersed and fixed, and as a result of the fine particle powder having special functions added at great length being included inside the porous body, the characteristic functions are efficiently exhibited. In some cases, there is a possibility that the original properties of the porous body may be impaired. In addition, in methods of fixing fine particle powder to the outer surface of a porous body by means such as adhesion or fusion, there are problems such as the effects derived from the characteristic functions of the fine particle powder easily falling off due to abrasion of the surface of the porous body. There is. For the reasons mentioned above, no satisfactory method has yet been proposed for efficiently fixing polyvinyl acetal-based porous materials without changing their properties or impairing the functions and characteristics of fine particle powders. It is. (Problems to be Solved by the Invention) As a result of intensive research in view of the above-mentioned problems of existing methods, the present inventors have found that by using a specific acrylic resin as a binder, mold-proofing and The present invention has been completed based on the discovery that a microparticle powder having bactericidal properties can be firmly fixed to a polyvinyl acetal porous material with good water resistance, and that the functions of the microparticle powder can be sufficiently maintained. The purpose is to provide a method for efficiently producing a polyvinyl acetal-based porous material having antifungal or bactericidal properties without impairing any of the desirable properties of the polyvinyl acetal-based porous material. It is in. (Means for Solving the Problems) The above purpose is to apply a solution or dispersion of an acrylic resin containing microparticle powder having antifungal or bactericidal properties to a polyvinyl acetal porous material, and then dry it. and a method of insolubilizing the acrylic resin and fixing the fine particle powder to a polyvinyl acetal porous body, the method comprising a low-temperature self-crosslinking type acrylic acid ester copolymer in which the acrylic resin crosslinks at 100°C or less. This is achieved by a manufacturing method characterized by coalescence. The fine particle powder used in the present invention has antifungal or bactericidal properties and has a particle size smaller than the pore size of the polyvinyl acetal porous material used. As such,
For example, those made of metals, organic compounds, reactive resins, etc. can be mentioned, and specifically, zeolite particles holding metal ions having antibacterial effects can be mentioned. The concentration of the fine particle powder in the acrylic resin solution or dispersion may be appropriately set depending on the required performance of the final target composite. It is preferable to set it within the range of 0.1 to 5 wt%. The acrylic resin used in the present invention is a low-temperature self-crosslinking acrylic ester copolymer that crosslinks at 100°C or lower. Since the above acrylic resin self-condenses at a relatively low temperature, the condensation progresses at the same time as drying, and there is no need for heat treatment at a temperature of 100°C or higher after drying, so that the properties of the polyvinyl acetal porous material are not impaired. Nor. If a polyvinyl acetal porous material is treated at a temperature higher than 100°C, undesirable phenomena such as deformation, deterioration, and discoloration may occur as the heat resistance temperature is exceeded, which may impair the inherent desirable properties of the polyvinyl acetal porous material. Therefore, the acrylic resin used in the present invention is limited to water-soluble or emulsion type resins that self-condense at temperatures below 100°C. Further, the resin concentration in the aqueous solution or emulsion of the acrylic resin is preferably 5 to 5.
It is about 15wt%. If the resin concentration is too low, the adhesion force of the fine particle powder will decrease, while if it is too high, the viscosity of the liquid will increase, the dispersibility of the fine particle powder will decrease, and the amount of resin attached to the porous body will be greater than necessary. If the amount is too large, the inherent properties of the porous body tend to be impaired. The acrylic resin used in the method of the present invention condenses and becomes water-insoluble through heat treatment to form a thin film on the surface of the porous body, and functions as a binder. At this time, the acrylic resin is not affected by the porosity of the fine particle powder and does not penetrate deeply into the fine particle powder, forming a large water-insoluble film on the relatively surface area of the powder, and forming a polyvinyl acetal porous film. It is fixed to the body. Since the acrylic resin forms a film only on relatively surface portions of the fine particle powder, the characteristic functions of the fine particle powder are sufficiently maintained. This tendency becomes more pronounced as the hydrophilicity of the resin constituting the porous body increases and as the hydrophobicity of the fine particle powder increases. The polyvinyl acetal porous material used in the present invention has extremely high hydrophilicity, and the effect will be even greater if, for example, a highly hydrophobic and porous fine particle powder such as zeolite is used as the fine particle powder. . The dispersion prepared as described above is applied to the polyvinyl acetal porous body, but the application method is not particularly limited. For example, spraying, impregnation, post-impregnation, etc. This may be carried out by any known appropriate method, such as a method of adjusting the application amount by narrowing the amount. The method of spraying is suitable for fixing the fine particle powder unevenly distributed on the surface layer of the polyvinyl acetal porous body, and the method of impregnation is suitable for uniformly applying the fine particle powder to the inner layer of the porous body. Suitable for fixing. The product thus obtained is then heat treated at a predetermined temperature, which is a temperature higher than the self-condensation temperature of the acrylic resin and lower than 100°C. Under such heat treatment conditions, the acrylic resin becomes condensed and insolubilized in water, and the drying progresses as well. At this time, it is also effective to use a small amount of a curing accelerator (catalyst). If the heat treatment temperature is 100℃ or less, the polyvinyl acetal porous material will also change in quality.
Undesirable phenomena such as deformation do not occur. In the method of the present invention, if another thermosetting resin is used in place of the acrylic resin, a heat treatment step of about 120 to 180°C is required following drying, but according to the method of the present invention, By completely omitting that step, it is possible not only to suppress deterioration due to heat treatment, but also to shorten heat treatment time and save thermal energy. (Effects of the Invention) According to the method of the present invention, it is possible to firmly immobilize microparticle powder having antifungal or bactericidal properties on a polyvinyl acetal porous material, and to fully exhibit its properties. This makes it possible to obtain a polyvinyl acetal-based porous material that prevents the generation of mold. Furthermore, since crosslinking is carried out at a low temperature of 100° C. or lower, it is fully possible to obtain completely equivalent physical properties without impairing the original physical properties of the polyvinyl acetal porous material. Therefore, when the polyvinyl acetal porous material obtained by the method of the present invention is used as a cosmetic puff material, which is one of its main uses, it has conventionally been difficult to use the product due to problems such as mold generation. Although its value and life as a product were limited, it has permanent mildew resistance,
Since the puff material has a bactericidal effect, its commercial value is improved. Hereinafter, the method of the present invention will be specifically explained with reference to Examples. (Example) Complete saponification with average polymerization degree of 1200 and saponification degree of 99 mol%
The average pore size is obtained by formalizing PVA in the presence of a sulfuric acid catalyst using starch as a pore-forming aid.
A soft polyvinyl acetal porous body with a size of 500μ and a porosity of 92% was produced. Next, type A zeolite with an average particle size of 10μ (0.94NaO・Al ₂ O ₃・1.92SiO ₂・xH ₂
250 g of dried fine powder of O) was collected, 500 ml of 1/50M silver nitrate aqueous solution was added, and the resulting mixture was kept under stirring at room temperature for 23 hours to perform ion exchange, and then filtered and washed with water to remove the excess. silver ions were removed. Next, when the washed silver zeolite was dried at 100-105℃ and crushed, the silver content was 2.6%, and the specific surface area was 2.6%.
629 m ² /g of silver-zeolite conversion was obtained.
This product was in the form of a finely powdered solid and had antibacterial and antifungal properties. Prepare EXP-220 manufactured by Teikoku Kagaku Sangyo as an acrylic resin binder and dilute it with water to 10wt.
% water-based emulsion. Add to this the above-mentioned silver
Fine particle powder of zeolite conversion product was added at a ratio of 1.0 wt%, and thoroughly stirred to prepare a uniform dispersion. The above-mentioned polyvinyl acetal porous sheet (300 mm x 230 mm x 15 mm) was placed in this dispersion, immersed for about 30 minutes, and then squeezed using a squeezing roller. After that, the sheet was placed in a dryer at 85°C.
Heat treatment was performed for a period of time. The heat-set polyvinyl acetal porous sheet to which fine particles of the silver-zeolite conversion product were fixed had no elasticity and was in the form of a hard plate. Next, this sheet was punched out into a circular shape and used as a test piece and subjected to the following tests. As mentioned above, the test piece was in the form of a hard plate, but when it was moistened with water, it became flexible. This wet test piece was punched out into a circular shape and used as sample No. 1 to test the usability as a puff for water-based makeup.
After being selected 10 times, the specimens were kept moist to give them elasticity, and the mold-producing properties were checked. The results are shown in Table 1. Using the same formulation as above, adjust the emulsion concentration.
Prepare samples with 1wt% and 20wt%,
Samples No. 2 and No. 3 were used for the same test. The results are summarized in Table 1.

[Table] As is clear from Table 1, No. 1 had good texture and anti-mildew properties, but No. 2 had slightly poor anti-mildew retention, and No. 3 had a tendency to have a slightly hard texture. Admitted. Incidentally, EXP-220 used in this example is a self-crosslinking acrylic acid ester copolymer having a self-condensation temperature of 100° C. or less, and forms a stable aqueous emulsion.

Claims (1)

[Claims] 1 A dilute solution or dispersion of an acrylic resin containing a fine particle powder having antifungal or bactericidal properties is applied to a polyvinyl acetal porous body, and then dried to insolubilize the acrylic resin and form a fine particle powder. A method of immobilizing on a polyvinyl acetal porous body, the acrylic resin having anti-fungal and sterilizing properties, characterized in that the acrylic resin is a low-temperature self-crosslinking acrylic ester copolymer that crosslinks at 100°C or less. A method for producing a polyvinyl acetal porous material.