JPH0470B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides micronized 2-mercaptopyridine-N
-Relating to an oxide polyvalent metal salt and a method for producing the same. 2-Mercaptopyridine-N-oxide polyvalent metal salt (hereinafter referred to as "Mept") is effective as a disinfectant, and is widely used as an anti-dandruff agent in shampoos, rinses, etc. as well as a general disinfectant. It is used for. The polyvalent metals of Mept include calcium, magnesium, barium, strontium, zinc, cadmium, tin,
Among these, zinc salts are widely used. However, these Mepts are poorly soluble and have a high specific gravity; for example, the solubility of the zinc salt (hereinafter referred to as "Zpt") in water is 15 ppm at 25°C, and the specific gravity is 1.8, making it difficult to sell and supply them. It was carried out in the form of powder or aqueous dispersion.
Furthermore, due to its high specific gravity, Mept has the drawback of being easily agglomerated, sedimented, and separated even when suspended and dispersed in a solvent. Conventionally, shampoos and rinses containing Mept have been available on the market, but in order to stably incorporate Mept into the composition, it was necessary to increase the viscosity or incorporate special polymers, clay minerals, etc. . For this reason, in terms of product performance, shampoos, for example, have drawbacks such as poor foaming properties and poor feel after shampooing. Recently, as techniques for stably retaining Mept in compositions, a method of using it in combination with hydroxyalkyl cellulose (Japanese Patent Application Laid-Open No. 57-80499) and a method of using it in combination with an amphoteric polymer compound (Japanese Patent Application Laid-Open No. 54-41909) have been developed. issue),
A method of using it in combination with HPC (Japanese Unexamined Patent Publication No. 53-97010) and a method of using it in combination with polyacrylic acid/polyacrylic acid ester (Japanese Unexamined Patent Publication No. 52-74585) have been reported. However, these technologies still use special polymers, increasing the cost of the product,
Performance constraints have not been resolved, and all of these techniques have been applied only to shampoo systems, and the possibility of application to other products has not been made clear at all. Therefore, the present inventors investigated Mept, an excellent antibacterial agent.
We were conducting intensive research to stably incorporate Mept into general shampoos, hair rinses, etc. without using special polymers, etc., and found that if the particle size of Mept was reduced to a specific particle size distribution or less, it could be incorporated into the composition. The dispersion stability of Mept is significantly improved, and the adsorption of finely divided Mept to the skin and hair is improved, so the bactericidal and anti-dandruff effects of shampoos, hair rinses, etc. containing Mept are improved.
And these performances are inversely proportional to the particle size of Mept,
It has been found that the smaller the particle size, the better. The present inventor previously reported Mept in which particles with a particle size of 0.2μ or less accounted for 50wt% or more and a method for producing the same (Japanese Patent Application No. 122845/1984 (Japanese Unexamined Patent Publication No. 122845/1983).
(See Publication No. 16972). However, in general, when the particle size is halved, the total surface free energy within the system doubles, making the entire system unstable, which results in particle aggregation, making it impossible for particles of 0.1μ or smaller to exist stably. It was extremely difficult. Under such circumstances, the present inventor conducted intensive research to provide Mept with even smaller particle size, and as a result,
This objective was successfully achieved by using specific dispersants. That is, the present invention provides micronized Mept in which particles having a particle size of 0.1 μm or less account for 50 wt % or more, a method for producing the same, and an antibacterial composition containing such Mept. The micronized Mept of the present invention has 50 wt% or more of particles with a particle size of 0.1 μ or less, and 50 wt% or more of particles with a particle size of 0.1 μ or less, and 15 wt% of particles with a particle size of 0.2 to 0.5 μ. 5wt% or less of particles with a particle size exceeding 0.5μ and an average particle size of 0.1μ or less, particularly preferably 70wt% or more of particles with a particle size of 0.1μ or less and 0.2 to 0.5μ It is preferable that the particle size of the particles is 10 wt % or less, that it does not substantially contain particles with a particle size exceeding 0.5 μm, and that the average particle size is 0.08 μm or less. The micronized Mept of the present invention has an average molecular weight of 10,000 to
It is produced by stirring together with rigid media having a particle size of 0.2 mm or less in the presence of 1 million liters of (meth)acrylic acid-styrene sulfonic acid copolymer salt. (Meth)acrylic acid used as a dispersant
The styrene sulfonic acid copolymer salt is a water-soluble copolymer salt of acrylic acid or/and methacrylic acid and styrene sulfonic acid, and is produced by a known method. The molar ratio of (meth)acrylic acid to styrene sulfonic acid in the copolymer is 1/10 to 10/1, preferably 1/3 to 7/1. In addition, the average molecular weight is 10,000~
1 million, preferably 100,000 to 700,000. This molecular weight is important; if it is less than 10,000, Mept will not be made into fine particles or the particles will be significantly aggregated. Moreover, if it exceeds 1 million, the water-soluble copolymer itself has a high viscosity and is difficult to handle. Salts of the copolymer include sodium salt, potassium salt, ammonium salt, monoethanolamine salt, diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt, triisopropanolamine salt, 2-amino- 2-methylpropane-1,
Examples include 3-diol salts. Further, an unneutralized portion may be left to an extent that does not impede performance. Furthermore, the copolymer according to the present invention may be in the form of a copolymer containing a third component to an extent that does not impair performance, and this third component may include various types of styrene, acrylamide, methacrylsulfonic acid, vinylsulfonic acid, etc. Sulfonic acid, 2-hydroxyethyl acrylate, various acrylic esters, various methacrylic esters, N-methylol acrylamide, or other copolymerizable substances can be used. The amount of the water-soluble copolymer salt added is preferably 0.1 wt% or more, particularly 0.5 to 10 wt%. Mept, which is a raw material, is used by dispersing a commercially available powder in water, but a commercially available dispersion may also be used. Further, the concentration of the dispersion liquid is preferably in the range of 5 to 70 wt% Mept, and in consideration of production efficiency, a high concentration is particularly preferable. Furthermore, the media preferably have a particle size of 0.2 mm or less, particularly 0.1 to 0.2 mm. When using media smaller than 0.1 mm, it is possible to make fine particles, but the mixture of media and Mept becomes highly viscous.
It becomes difficult to handle. The material of this media is rigid, such as Ottawa sand, glass, alumina,
Although zircon and the like can be used, glass is preferable. Sand mills, sand grinders, etc. are known as devices for stirring Mept and media into fine particles, but the sand mills and sand grinders used in the present invention may be of generally known types, and both vertical and horizontal types can be used. can. Further, a commonly used type of disk can be used. The temperature during microparticulation is preferably 5 to 30°C. If the temperature exceeds 30°C, it is not preferable because it takes a long time to form fine particles and it becomes difficult to form fine particles. The mixing ratio of the media and the Mept dispersion during micronization is in the range of 40/60 to 80/20, preferably 60/40 to 70/30, in terms of volume ratio. The micronized Mept of the present invention is obtained by micronizing the Mept in a sand mill, separating the media and the Mept dispersion liquid by pressure filtration or centrifugation, and further washing the media with water if necessary. The micronized Mept thus obtained contains 50wt% or more of particles with a particle size of 0.1 μ or less (particle size and its distribution were measured using a centrifugal automatic particle size distribution analyzer CAPA-
500 (Horiba, Ltd.). The same applies to the following examples), and particles with a particle size of 0.2 μ or less are
Dispersion stability is further improved compared to dispersions containing 50 wt% or more. In addition, compared to conventional Mept, it has better adsorption stability to hair, skin, tree bark, building materials, etc., and has an excellent bactericidal effect, so it can be used not only in hair cosmetics as an anti-dandruff agent, but also in conventional dispersion stability. It can also be used in hair cosmetics, disinfectants, etc. that use water-alcohol dispersions, which have been particularly problematic. Especially in water-alcohol systems,
The stability is significantly improved compared to when using a dispersion containing 50 wt % or more of particles having a particle size of 0.2 μ or less, but this is due to the smaller particle size. Next, the present invention will be explained with reference to Examples and Comparative Examples. Example 1 23g of commercially available Zpt powder, formula (The molecular weight of the compound of the above formula is 680,000.) 4.5 g of water-soluble copolymer salt represented by, 63 g of water, and 187 g of glass beads (media) of 0.1 to 0.2 mm.
(media/dispersed liquid volume ratio = 63/37),
The disk was rotated at a circumferential speed of 6 m/sec for 12 hours in a sand grinder (manufactured by Igarashi Kikai) with an internal volume of 400 ml. The temperature inside the sand grinder is 20~
It is 25℃. Further, this is filtered under pressure to obtain 40 g of micronized Zpt dispersion. Also, 2 with 70g of water
After washing the media twice, 98wt% of Zpt can be recovered. As shown in Table 1, this micronized Zpt is
The particle size distribution consists of 91 wt% of particles having a particle size of 0.1μ or less. Example 2 Commercially available Zpt powder 14g, formula (The molecular weight of the compound of the above formula is 320,000) 45 g of water-soluble copolymer salt represented by, 72 g of water and
Mix 187 g of glass beads (media) of 0.1 to 0.2 mm (media/dispersed liquid volume ratio = 63/37), and grind the disc in a sand grinder with an internal volume of 400 ml (manufactured by Igarashi Kikai) for 12 hours at a circumferential speed of 6 m/3. Rotate in seconds. The temperature inside the sand grinder is 20-25
It is ℃. Furthermore, by filtering this under pressure, 35 g of micronized Zpt dispersion liquid is obtained. As shown in Table 1, this finely divided Zpt has a particle size distribution in which 77 wt% of particles have a particle size of 0.1 μ or less. Example 3 Commercially available Zpt powder 14g, formula (The molecular weight of the compound of the above formula is 100,000) 45 g of water-soluble copolymer salt, 72 g of water and
Mix 203 g of glass beads (media) of 0.1 to 0.2 mm (media/dispersed liquid volume ratio = 65/35) and grind the disc in a sand grinder with an internal volume of 400 ml (manufactured by Igarashi Kikai) for 3 hours at a circumferential speed of 6 m/sec. Rotate with . The temperature inside the sand grinder is 20-25℃
It is. Furthermore, when this is filtered under pressure, it becomes fine particles.
You can get Zpt38g. As shown in Table 1, this finely divided Zpt has a particle size distribution in which 50 wt% of particles have a particle size of 0.1 μ or less.

[Table] Example 4 Commercially available Zpt powder 23g, formula (The molecular weight of the compound of the above formula is 260,000) 4.5 g of water-soluble copolymer salt, 63 g of water, and
Mix 187 g of glass beads (media) of 0.1 to 0.2 mm (media/dispersed liquid volume ratio = 63/37), and grind the disc in a sand grinder with an internal volume of 400 ml (manufactured by Igarashi Kikai) for 8 hours at a circumferential speed of 6 m/3. Rotate in seconds. The temperature inside the sand grinder is 20-25
It is ℃. Furthermore, by filtering this under pressure, 50 g of micronized Zpt dispersion liquid is obtained. As shown in Table 2, this finely divided Zpt has a particle size distribution in which 100wt% of particles have a particle size of 0.1μ or less. Example 5 23g of commercially available Zpt powder, formula (The molecular weight of the compound of the above formula is 380,000) 4.5 g of water-soluble copolymer salt, 63 g of water, and
Mix 187 g of glass beads (media) of 0.1 to 0.2 mm (media/dispersed liquid volume ratio = 63/37), and grind the disc in a sand grinder with an internal volume of 400 ml (manufactured by Igarashi Kikai) for 8 hours at a circumferential speed of 6 m/3. Rotate in seconds. The temperature inside the sand grinder is 20-25
It is ℃. Furthermore, by filtering this under pressure, 45 g of micronized Zpt dispersion liquid is obtained. As shown in Table 2, this finely divided Zpt has a particle size distribution in which 100wt% of particles have a particle size of 0.1μ or less. Example 6 23g of commercially available Zpt powder, formula (The molecular weight of the compound of the above formula is 350,000) 4.5 g of water-soluble copolymer salt, 63 g of water, and
Mix 187 g of glass beads (media) of 0.1 to 0.2 mm (media/dispersed liquid volume ratio = 63/37), and grind the disc in a sand grinder with an internal volume of 400 ml (manufactured by Igarashi Kikai) for 8 hours at a circumferential speed of 6 m/3. Rotate in seconds. The temperature inside the sand grinder is 20-25
It is ℃. Further, this is filtered under pressure to obtain 40 g of micronized Zpt dispersion. As shown in Table 2, this finely divided Zpt has a particle size distribution in which 100wt% of particles have a particle size of 0.1μ or less.

[Table] Comparative example 1 Commercially available Zpt powder 23g, formula (The molecular weight of the compound of the above formula is 6200) 4.5 g of water-soluble copolymer salt, 63 g of water, and 187 g of glass beads (media) of 0.1 to 0.2 mm.
(media/dispersed liquid volume ratio = 63/37),
The disk was rotated at a circumferential speed of 6 m/sec for 3 hours in a sand grinder (manufactured by Igarashi Kikai) with an internal volume of 400 ml. The temperature inside the sand grinder is 20~
It is 25℃. Furthermore, when this is filtered under pressure, micronized Zpt41g is obtained. As shown in Table 3, this finely divided Zpt contains 2wt% of particles having a particle size of 0.1μ or less. Comparative Example 2 Commercially available Zpt powder 14g, formula (The molecular weight of the compound of the above formula is 500,000.) 2.3 g of water-soluble polymer, 74 g of water, and 0.1
Mix 187 g of ~0.2 mm glass beads (media) (media/dispersed liquid volume ratio = 63/37) and reduce the internal volume.
400ml sand grinder (manufactured by Igarashi Machinery)
When the disk is rotated at a circumferential speed of 6 m/sec for 3 hours, intense cream-like foaming occurs, and as shown in Table 3, there are no particles with a particle size of 0.1 μ or less in this micronized Zpt. do not.

【table】

[Table] Comparative Example 3 Commercially available Zpt dispersion A or B (both
Mix 90g of 50wt% effective content and 187g of 0.1-0.2mm glass beads (media) (media/dispersed liquid volume ratio = 63/37), and grind the disc in a sand grinder with an internal volume of 400ml (manufactured by Igarashi Kikai). Rotate at a circumferential speed of 6 m/sec for 5 hours. The temperature inside the sand grinder is 20-25 °C. Furthermore, when this is filtered under pressure, 37g or 34g of micronized Zpt can be obtained. As shown in Table 4, this finely divided Zpt contains less than 50 wt% of particles having a particle size of 0.1 μ or less.

[Table] Comparative Example 4 Using commercially available Zpt powder and various dispersants
90 g of Zpt dispersion was prepared and micronized under the same conditions as in Comparative Example 3. The results are shown in Table 5. In all cases, less than 50 wt% of particles have a particle size of 0.1 μ or less.

【table】

[Table] Example 7 Commercially available Zpt, Zpt of Japanese Patent Application No. 58-122845 (comparative invention product), and Zpt of the present invention were dispersed in water and their dispersion stability was compared. The results are shown in Table 6.

[Table] Determine the subsequent state of dispersion with the naked eye.
Example 8 ^35S -labeled Zpt of the present invention product (average particle size 0.08 μ), comparative invention product (average particle size 0.11 μ), and commercial product (average particle size 0.72) was mixed with 1.0% polyoxyethylene (2) lauryl sulfate. Dispersed in 500ml of sodium salt aqueous solution,
30 mg of hair bundles were added to this dispersion and immersed for 1 minute while stirring at 100 rpm. Next, wash this hair bundle under running water for 15 minutes.
Repeat rinsing for 2 seconds, air dry, then accurately weigh 10mg, put it in a 20ml vial, and add it to Sol En.
It was dissolved in 350.1 ml. Add this to 10ml of scintillator
was added and measured using a liquid scintillation counter to determine the amount of Zpt remaining adsorbed. This result is the seventh
Shown in the table.

[Table] Example 9 Anti-dandruff agent: Zpt (Example 2) 2.0% Propylene glycol 5.0% Ethanol 30% Fragrance Trace amount Water Total 100% This anti-dandruff agent has a remarkable anti-dandruff effect and is stable for more than 3 months at room temperature. It was hot. On the other hand, commercially available Zpt
The sedimentation of Zpt was observed in 1 day in the case where Zpt was used, and in 10 days in the case where the comparative invention Zpt was used.

Claims (1)

[Scope of Claims] 1. A micronized 2-mercaptopyridine-N-oxide polyvalent metal salt containing 50 wt% or more of particles having a particle size of 0.1 μ or less. 2 A dispersion of a polyvalent metal salt of 2-mercaptopyridine-N-oxide is mixed into a rigid body with a particle size of 0.2 mm or less in the presence of a (meth)acrylic acid-styrene sulfonic acid copolymer salt having an average molecular weight of 10,000 to 1,000,000. A method for producing a micronized 2-mercaptopyridine-N-oxide polyvalent metal salt comprising 50 wt% or more of particles having a particle size of 0.1 μm or less, the method comprising stirring together with a media. 3. An antibacterial composition containing as an active ingredient a micronized 2-mercaptopyridine-N-oxide polyvalent metal salt containing 50 wt% or more of particles having a particle size of 0.1 μm or less.