JPH06166713A - Production of polyvinyl acetal-based porous material having antimicrobial and mildew-proofing property - Google Patents

Abstract

PURPOSE:To provide a polyvinyl acetal-based porous material, to be always used in wet state, extremely apt to multiply microorganisms, with antimicrobial and mildew-proofing properties. CONSTITUTION:As a method for antimicrobial and mildew-proofing processing of a polyvinyl acetal-based porous material, an aqueous solution of a polyvinyl alcohol is mixed with starch and formaldehyde, blended with sulfuric acid, hydrochloric acid, etc., and acidified to give a solution, which is heated and incorporated with an antimicrobial and mildew-proofing agent during polymerization by acetalization to give a porous material. In particular, after a polyvinyl acetal-based porous material is obtained by using an antimicrobial and mildew- proofing agent to dissolve in acidity, the antimicrobial and mildew-proofing agent is returned to a water-insoluble neutral salt by treating the polyvinyl acetal-based porous material with an alkali aqueous solution to further improve water resistance.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an antibacterial agent excellent in water resistance,
Regarding production of a polyvinyl acetal-based porous body having antifungal property, more specifically, an acidic aqueous solution of polyvinyl alcohol (hereinafter abbreviated as PVA) is added to formalin,
This is a method for producing a polyvinyl acetal-based porous molded product after adding starch and antibacterial and antifungal compounds.

[0002]

2. Description of the Related Art Starch, formalin and acid are added to an aqueous solution of polyvinyl alcohol, and the solution is added to 40-90.
It can be easily produced by carrying out a holding reaction at a temperature of 10 to 24 hours. The obtained porous body molded product is thoroughly washed with water to remove excess formalin and an acidic substance. By this water washing, starch that does not participate in the reaction is washed away, and a porous body molded product is obtained.

This porous molded article is excellent in water absorption and is often used for wiping bath sponges, kitchen sponges, automobile cleaning sponges and the like, but when it has fine pores, it can be generally used, but in particular, Good texture is preferred as a makeup puff. However, the drawback is that it becomes very hard when dried. Therefore, it is always kept in a wet state, but starch is used to generate pores. Most of this starch is removed during washing with water, but it is impossible to completely remove it. Therefore, there is a drawback that mold is very likely to occur.
Conventionally, antibacterial and antifungal agents have been used to prevent this. The method of using the antibacterial and antifungal agent is carried out by post-processing after forming a porous body molded product. Since this porous molded article is always used in a wet state with water, each time the chemical is washed away and the antifungal property disappears, mold is generated and it cannot be used.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a method for imparting antibacterial and antifungal properties to a polyvinyl acetal-based porous material which is always used in a wet state and in which microorganisms are easily proliferated. We have discovered a way to add to PVA solutions during body manufacture.

According to this method, the effect could be improved considerably as compared with the conventional post-processing. This is because the antibacterial and antifungal agents are retained in the PVA resin forming the sponge and are retained in the molded porous body, resulting in very little loss of water, resulting in long-lasting effect. Is also a considerable improvement. Patents relating to the production of the PVA-based porous material include JP-B-47-46455 and JP-B-5.
2-10147, Japanese Patent Publication No. 56-52934, JP-A-63
-245447 etc. are disclosed.

[0006]

As a method for further improving antibacterial and antifungal properties, the present invention uses an antibacterial and antifungal agent which is soluble in an acidic solution during the production of a polyvinyl acetal-based porous body, and the resulting porosity is obtained. By treating the molded body with an alkaline solution, the antibacterial and antifungal agent, which had been dissolved as an acid salt by returning it to the original neutral salt state, is made insoluble again in water to prevent the antibacterial and antifungal agents for a long time. The present invention has been completed by discovering that a PVA porous body having moldability can be obtained.

As antibacterial and antifungal agents which can be used in the present invention and which are soluble in an acidic solution, 2- (4-thiazolyl) benzimidazole, 2-methoxycarbonylbenzimidazole and the like can be used. After adding starch to the PVA solution, it is heated to gelatinize, and then cooled. An acid is added to this solution to adjust the pH to 1.0 to 2.0, formaldehyde is further added, and the reaction is held in a thermostatic chamber at 40 to 90 ° C. for 10 to 24 hours to obtain a flexible polymer. This polymer is washed with water to remove excess formalin, acid and starch not involved in the reaction to obtain a porous body. When this porous body is washed with an alkaline solution such as an aqueous solution of sodium carbonate, the acid salt is neutralized and the acid salt of the antibacterial and antifungal agent contained inside becomes a neutral salt, again becoming a compound insoluble in water and the antibacterial and antifungal agent. The agent can be made water resistant.

As another method, an antibacterial or antifungal agent which is insoluble in water is used as a water suspension. In addition, a water-resistant polyvinyl acetal-based porous body is prepared by dissolving a drug in an organic solvent, adding a surfactant and emulsifying and dispersing in water, and adding the solution to a PVA solution to form a porous body by the same method. Can be obtained.

The PVA solution used in the present invention is, in addition to PVA, a mixed solution of a pore-forming agent, formaldehyde and an acid. In addition to this, a colorant, a fibrous material, an inorganic powder, or other filler may be used in combination.

The PVA used in the present invention is obtained by saponifying polyvinyl acetate and has a polymerization degree of 400 to 400.
0, the degree of saponification is preferably 70-100%, but complete saponification,
Either partial saponification can be used. Further, those having a branch, copolymerization with other monomers, or a single compound or a mixture of two or more compounds can be used.

As an auxiliary agent for forming pores, usually,
It is starch, but in addition, starch derivatives, wood flour, fiber powder, carboxymethyl cellulose, and the like. Common starches include potato, rice, sweet potato, tapioca, sago,
Wheat, corn starch, etc. are used as they are or after being gelatinized. In addition, modified starch such as oxidized starch, cationic starch, phosphoric starch, soluble starch, dextrin and the like can also be used. In addition, a surfactant is also used.

As the aldehyde, formaldehyde,
Many aldehydes such as acetaldehyde, butyraldehyde, and other aliphatic compounds, benzaldehyde, naphthalinaldehyde, and other aromatic aldehydes acrolein or glyoxal, adipaldehyde, and other dialdehydes, or mixtures of these can be used. Formaldehyde is most often used from the viewpoint of economy and economical aspects.

Most of the acids used as acetalization catalysts are mineral acids such as sulfuric acid, hydrochloric acid and phosphoric acid, but organic acids are sometimes used, but mineral acids are used in consideration of cost. There are many examples. The amount of PHA used is 1.0-
It is often used in the range of 2.0.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) 15 of Gohsenol C-500R (product of Nippon Synthetic Chemical Industry Co., Ltd.) as polyvinyl alcohol
% Solution, add 7 parts corn starch and 37 parts water,
Heat to 90-95 ° C with good stirring to completely gelatinize and cool to about 40 ° C. Add 12 parts of 50% sulfuric acid and 3 parts to this solution.
10% of 7% formalin and each% of the following antibacterial and antifungal agents are added, poured into a resin vat having a size of 20 cm × 15 cm × a depth of 3 cm, and kept in a thermostatic chamber at 60 ° C. for 24 hours for reaction. After the reaction was completed, the porous body was taken out and washed with water, and the washing method was mangle. Mangle is 1 kg /
The pressure was adjusted to cm ² and squeezed. Put this squeezed thing in water and let it fully wet. This operation was repeated 50 times and 100 times repeatedly, and the test was conducted as a sample of the antibacterial and antifungal test.

[Reference Example] As a comparative experiment, a post-treatment of an antibacterial / antifungal agent on a polyvinyl acetal-based porous material, which has been conventionally performed, was carried out by the following method for comparison. (Medication) No. 1 Benzalkonium chloride solution (50%) No. 22 g of 2- (4-thiazolyl) benzimidazole was dissolved in 50 g of N-methylpyrrolidone and 20 g of xylene, and then 20 g of nonylphenol was added and completely dissolved. (Processing method) Drug No. 1, No. 2 with water, 0.5 each
% Aqueous solution, the polyvinyl acetalized porous body is thoroughly washed with water, and then the well-squeezed porous body is immersed in the chemical solution to sufficiently absorb the chemical solution. After repeating this operation three times, it was used as a sample. The results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

Antibacterial and antifungal agents used in the examples of the present invention No. 1 Didecyldimethylammonium chloride 50% aqueous solution

No. 2 2-Methoxycarbonylaminobenzimidazole
10% by weight of 4'-n-dodecylbenzene sulfonate
(All of which are shown below by weight) were dissolved in 80% ethanol, and 10% nonylphenol ethylene oxide 10 mol adduct was added as an emulsifier to give a preparation.

No. 3 2-Benzimidazole carbamic acid methyl ester 1
0 g and 2 g of 2,4,4'-trichloro-2'-hydroxy-diphenyl ether are added to 85 g of water. After adding 3 g of sodium dodecylbenzene sulfonate as a dispersant to this liquid, a homodisper is used to prepare a dispersant in water.

Example 2 An acetalization reaction was carried out under the same conditions as in Example 1. The antibacterial and antifungal agent used in this reaction was 10 g of 2- (4-thiazolyl) benzimidazole (No. 1) dissolved in 90 g of 10% sulfuric acid, and 2-methoxycarbonylbenzimidazole ( Acetalization was carried out using a drug prepared by dissolving 10 g of No. 2) in 90 g of 10% sulfuric acid. After the reaction, take out the porous body from the container and use mangle 1
It was washed with water twice, and the 5% sodium carbonate solution was allowed to stand overnight in a solution of about 10 times the weight of the porous body. By this treatment, the acid was neutralized to the inside of the porous body.

After this operation, washing with water was carried out 50 times and 100 times with mangle as shown in Example 1. still,
In this operation, even those not subjected to alkali washing were simultaneously washed with water by the mangle squeeze the same number of times, and then comparative experiments were conducted on the antibacterial and antifungal test. The results are shown in Tables 3 and 4.

[Table 3]

[Table 4]

[0020]

INDUSTRIAL APPLICABILITY A porous body molded product obtained by adding formaldehyde and starch to an aqueous solution of polyvinyl alcohol and acetalizing it under an acid catalyst is very prone to mold because starch is used as a raw material. When the porous molded article is used under conditions of drying, it becomes extremely hard, and therefore it is stored so that water is always present. Therefore, once mold is generated, it can hardly be removed, so a solution to this has been sought. For this reason, in some cases, it is molded into a sponge and then processed with an antibacterial and antifungal agent.
The sufficient effect was not obtained.

In the present invention, the water resistance is very good because it is added at the time of molding the porous body to form an acetal. Also,
Since an acid catalyst is used when acetalizing, an antibacterial / antifungal agent which is acidic and dissolves, for example, 2- (4-thiazolyl) benzimidazole and 2-methoxycarbonylbenzimidazole are added, and after the reaction, an alkaline substance such as sodium carbonate is added. By treating with an aqueous solution, the antibacterial and antifungal agent became the original water-insoluble compound, and a porous molded body having further excellent water resistance was obtained.

Claims (2)

[Claims] 1. An acetalization reaction by adding formaldehyde, an acid, and starch as a pore-forming aid to an aqueous polyvinyl alcohol solution, and further adding a compound having antibacterial and antifungal properties to the reaction system and heating to 40 to 90 ° C. A method for producing a polyvinyl acetal-based porous body having antibacterial and antifungal properties, which comprises performing 2. An antibacterial and antifungal agent soluble in an acidic solution is obtained by washing a porous body product obtained by an acetalization reaction of polyvinyl alcohol with an alkaline aqueous solution to render the compound water-insoluble and impart water resistance. Claim 1 characterized by the above.
A method for producing a polyvinyl acetal-based porous body having the antibacterial and antifungal properties described.