JPH1129403A - Aqueous antibacterial agent dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conveniently obtain an aqueous antimicrobial dispersion excellent in cold storage by adding an aggregation inhibitor consisting of a vinyl polymer into an aqueous dispersion containing a metal salt of 2-mercaptopyridine- N-oxide. SOLUTION: The objective dispersion excellent in cold storage stability with no losing the property of the dispersion prior to freezing even when remelted after being frozen is obtained by adding an aggregation inhibitor containing a vinyl polymer (a polyvinylpyrrolidone with a molecular weight of preferably 10000-40000) in a proportion of preferably 0.3-10.0 wt.% based on the dispersion into an aqueous antimicrobial dispersion containing a metal salt (preferably zinc salt) of 2-mercaptopyridine-N-oxide in an amount of 20-60 wt.%, preferably 30-50 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-temperature storage stability of a frozen aqueous dispersion of 2-mercaptopyridine-N-oxide metal salt which does not lose the properties of the dispersion before freezing even after rethawing. It relates to an aqueous antibacterial agent dispersion excellent in water resistance.

[0002]

2. Description of the Related Art Metal salts of 2-mercaptopyridine-N-oxide are useful as fungicides, especially zinc salts (hereinafter "ZP").
T) is widely used as an anti-dandruff agent in shampoos and rinses.

Conventionally, a commercially available ZPT aqueous dispersion is generally stable at room temperature, but has the drawback of causing agglomeration due to agglomeration when frozen and then re-thawed, or a remarkable change in viscosity. there were. Therefore, when transporting or storing the ZPT aqueous dispersion, it must be handled at least at 5 ° C. or higher.

[0004] In particular, when transported to winter or cold regions, or when stored in winter or cold regions, the ZPT aqueous dispersion sometimes freezes because it sometimes falls below freezing. After that, even if the frozen dispersion is re-thawed at room temperature for use, the dispersion may agglomerate, settle at the bottom of the container, generate particulate matter, or the viscosity may increase significantly, and In some cases, the product could not be used as a dispersion liquid because the product did not come out.

As described above, once the frozen dispersion is re-thawed at room temperature but loses its properties before freezing, there is no solution other than by phase separation and re-dispersion. The economic losses were great.

[0006] In general, ZPT is poorly soluble in water and is formulated in the form of a suspended solid, that is, an aqueous dispersion in the base of a hair treatment agent. From the viewpoint of, for example, stabilization, it has been attempted to make ZPT into fine particles or to add an anionic polymer compound, a nonionic polymer compound, an amphoteric polymer compound, and the like (Japanese Patent Publication No. 61-35186). JP-A-60-16973, JP-A-61-151110, JP-A-61-16973.
No. 15,1111, JP-A-62-63).
However, the dispersion thus prepared has a drawback that it settles and solidifies on the bottom of the container during storage, and even a relatively stable dispersion is separated by agglomeration due to salt mixing or freezing.

As a method for solving this problem, Japanese Patent Laid-Open No.
139613 discloses a method of adding a polyglycol / polyamine condensation resin or a polyglycol / polyamine / alkyl or alkyleneamine condensation resin. According to Examples 1 and 2 of the same specification, it is described that if polycoat H (manufactured by Henkel) is added to 2-mercaptopyridine-N-oxide zinc salt, aggregation does not occur even after freeze-thawing. .

However, this method uses polycoat H in an amount equal to or greater than the weight of zinc 2-mercaptopyridine-N-oxide, and requires a large amount of polycoat H, which is not economically advantageous. Since a large amount of polycoat H is used, it has a high viscosity and is inconvenient to handle, and when used in shampoos and rinses, compatibility with other additives in the shampoo and rinse must be considered. This is not always a good method. Also, 2
-A dispersion having a mercaptopyridine-N-oxide metal salt concentration of about 30%, and a commercially available ZPT concentration of 50%
This is not an advantageous method in terms of transportation as compared with. Further, when the amount of the resin added is small, there is no effect or insufficient effect when rethawing after freezing.

Japanese Patent Publication No. 7-506603 discloses a dispersion having excellent storage stability by mixing a plastisol containing a resin and a carrier and a biocide, heating the mixture, and then cooling the mixture. It has gained.

[0010] JP-A-8-503458 discloses that a concentrated solution is formed by mixing a biocide and a carrier, and the concentrated solution is heated to a high temperature and then cooled to improve storage stability. Excellent mixture is obtained.

However, in each of these methods, it is necessary to heat the material once to a high temperature and then cool it, so that the production process for obtaining a dispersion or a mixture is complicated. In addition, since two types of resin and carrier are used, it is not economically advantageous. In addition, the stability during freeze-thaw is still insufficient.

[0012]

Therefore, even when an aqueous dispersion of a metal salt of 2-mercaptopyridine-N-oxide is used after being frozen and then thawed again, the dispersion as described above is used. There has been a demand for an aqueous dispersion which is excellent in low-temperature storage stability without losing the properties and can be produced by a simple method.

[0013]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and as a result, have found that polyvinyl polymer is added to an aqueous antibacterial agent dispersion of 2-mercaptopyridine-N-oxide metal salt. Dispersion produced by only a simple operation of adding a small amount at room temperature and stirring is about-
Even if frozen at 5 ° C. to about −30 ° C., re-thawing causes aggregation, sedimentation at the lower part of the container, generation of particulate matter, a remarkable increase in viscosity, and no contents coming out of the container. 2-mercaptopyridine-N- excellent in low-temperature storage stability which does not lose the properties of the dispersion before freezing.
The inventors have found that an aqueous dispersion of an oxide metal salt can be obtained, and have completed the present invention.

The present invention relates to (1) an aqueous antibacterial agent dispersion containing a metal salt of 2-mercaptopyridine-N-oxide, comprising a vinyl polymer as an anti-agglomeration agent; An aqueous antimicrobial dispersion having excellent low-temperature storage stability that does not lose the properties of the dispersion before freezing even when thawed. (2) The content of the vinyl polymer is 0.3% by weight or more with respect to the dispersion. 0.0% by weight or less (1)
The aqueous antibacterial agent dispersion according to the above (3), wherein the vinyl polymer is
The aqueous antibacterial agent dispersion according to (2), which is polyvinylpyrrolidone, (4): the aqueous dispersion according to (1), (2), or (3), wherein the metal of the 2-mercaptopyridine-N-oxide metal salt is zinc. An antimicrobial agent dispersion.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The vinyl polymer used in the present invention has a 2-mercaptopyridine-N-oxide metal salt content of 20 to 60% by weight, preferably 3 to 3% by weight of the dispersion.
If the aqueous antibacterial agent dispersion of 0 to 50% by weight is added in an amount of 0.3% to 10.0% by weight, preferably 0.5% to 5% by weight based on the dispersion, Good.

The aqueous antimicrobial agent dispersion is prepared by adding a vinyl polymer to an aqueous antimicrobial agent dispersion of a metal salt of 2-mercaptopyridine-N-oxide at room temperature, or by adding 2-mercaptopyridine-N-oxide to the vinyl polymer. An aqueous antibacterial agent dispersion of an oxide metal salt may be added at room temperature and stirred and mixed for several hours using a general stirring and mixing device such as a propeller stirrer or a homomixer.

Examples of the vinyl polymer include polyvinyl pyrrolidone and polyvinyl isobutyl ether having a molecular weight of 10,000 to 40,000, and polyvinyl pyrrolidone is preferred.

[0018]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 1.0 g of polyvinylpyrrolidone having an average molecular weight of 10,000 was added to 200 g of a commercially available product A (having a ZPT concentration of about 50%), and the mixture was stirred and mixed at room temperature using a stirrer to obtain an aqueous antibacterial agent dispersion. Was.

Comparative Example 1 To 200 g of a commercially available product A (having a ZPT concentration of about 50%), 2.0 g of Polycoat-H (trade name) manufactured by Henkel Co. was added, and the mixture was stirred and mixed at room temperature using a stirrer. An agent dispersion was obtained.

Test Example 1 50 g of each of the dispersions of Example 1 and Comparative Example 1 and the dispersions of Commercial Product A and Commercial Product B were placed in 50 ml plastic bottles, sealed with a lid, and sealed as follows. Refreezing was performed after freezing under the following two conditions.

Condition 1: Starting from an initial temperature of 5 ° C., the temperature was lowered over 7 hours and cooled to −10 ° C. Next, it was left at −10 ° C. for 15 hours. At this time, the dispersion was frozen. Next, this was heated to 5 ° C. over 7 hours to be re-melted.

Condition 2: Left in a -20 ° C. constant temperature bath for 24 hours. At this time, the dispersion was frozen. This was then re-melted at room temperature.

Then, the following items were examined. (1) Caking: It was examined whether or not there was any content that hardened and hardly flowed in the plastic bottle. (2) Aggregation: The re-melted product was placed on a glass plate, and the presence or absence of particulate matter was examined. (3) Phase separation: It was examined whether or not phase separation occurred in the plastic bottle.

Table 1 shows the test results under the condition 1, and Table 2 shows the test results under the condition 2.

[0026]

[Table 1]

[0027]

[Table 2]

From the test results shown in Tables 1 and 2, the aqueous antibacterial agent dispersion of the present invention does not cause caking, aggregation and phase separation even after re-thawing after freezing, and has excellent properties in low-temperature storage stability. It became clear to show.

[0029]

The aqueous antibacterial agent dispersion obtained according to the present invention can be transported in cold places or winter seasons, or stored in cold places or winter seasons, etc. It has a very advantageous characteristic that it does not cause phase separation, aggregation, sedimentation, generation of particulate matter, etc. and does not lose the properties of the dispersion before freezing and has excellent low-temperature storage stability.

Claims (4)

[Claims] 1. An aqueous antibacterial agent dispersion containing a metal salt of 2-mercaptopyridine-N-oxide, characterized by containing a vinyl polymer as an anti-agglomeration agent. Aqueous antibacterial agent dispersion having excellent low-temperature storage stability that does not lose its properties. 2. The aqueous antibacterial agent dispersion according to claim 1, wherein the content of the vinyl polymer is from 0.3% by weight to 10.0% by weight based on the dispersion. 3. The aqueous antibacterial agent dispersion according to claim 2, wherein the vinyl polymer is polyvinylpyrrolidone. 4. The aqueous antimicrobial agent dispersion according to claim 1, wherein the metal of the metal salt of 2-mercaptopyridine-N-oxide is zinc.