JPH01317121A - Acicular antibacterial substance - Google Patents

Abstract

PURPOSE:To obtain a substance useful as a treating material for imparting antibacterial property and a coloring material and to improve the durability of the antibacterial effect by supporting an antibacterial metallic component to acicular titanium dioxide and/or acicular potassium titanate. CONSTITUTION:(i) Rutile titanium dioxide is mixed with (ii) an alkali metal salt and (iii) an oxy-phosphorus compound and calcined at 725-1000 deg.C to obtain an acicular titanium dioxide (a) having an average major diameter of >=1mum and an aspect ratio (major axis/minor axis) of >=3. Separately, an acicular potassium titanate (b) having an average major diameter of 1-100mum, an aspect ratio of 10-100 and composition of formula K2O.nTiO2 (n is 2-8) is produced by mixing (iv) a basic oxygen-containing alkali metal compound with (v) an oxygen-containing titanium compound, calcining the mixture at 500-900 deg.C and purifying and separating the calcined product. The objective substance can be produced by supporting (B) 0.001-35wt.% (based on the component A) of an antibacterial metallic component such as copper alloy, metallic silver or metallic zinc to (A) the component (a) and/or the component (b).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a needle-shaped antibacterial substance, which is useful as an antibacterial agent for plastics, rubber, fibers, etc.

[Conventional technology]

It is generally well known that metals such as copper and silver have antibacterial properties as a so-called trace metal action. It has also been proposed to use copper as a preventive agent, or to process copper metal into ultra-fine copper fibers, such as sterilizing filters, anti-algae filters, anti-algae nets, sterilizing and deodorizing clothing, and leather. Incidentally, in recent years, various types of damage caused by raw materials, industrial products, structures, etc. caused by microorganisms such as bacteria and other harmful organisms have been increasing, and many proposals have been made to prevent these, one of which is the above-mentioned. In addition to the use of metallic copper fibers, various forms of pest control means that utilize the antibacterial properties of the metal are being actively studied. For example, attempts have been made to support metal components on resin particles or solid particles such as zeolite.

[Problem that the invention seeks to solve]

The above-mentioned antibacterial metal-supported substances are difficult to obtain in fine particles, the supported metal components are easily detached from the particle surface, or the metal-supported substances are used in paint coatings, resin molded products, etc. , resin films, coating agents for paper processing, and other media, and furthermore, in order to obtain sufficient antibacterial effects, it is necessary to increase the amount of addition, and as a result, coated products using these There is a desire to improve the color tone and strength of molded products, and it is difficult to obtain desired color tone and durability.

[Means for solving problems]

In the process of conducting various studies to solve the above-mentioned problems, the present inventors found that titanium dioxide particles have extremely excellent adhesion of antibacterial metal components on the particle surface, and therefore have a long-lasting antibacterial effect. Based on the knowledge that the antibacterial activity could be increased, a patent application was filed in Japanese Patent Application No. 63-64392 for an antibacterial powder in which an antibacterial metal component is supported on titanium oxide base particles. After further investigation, we found that acicular titanium dioxide and acicular potassium titanate have the same surface properties as titanium dioxide particles, and that these thorn-like substances can be applied to various resins, rubbers, fibers, etc. By blending,
The present invention was completed based on the knowledge that it is possible to increase their strength and also improve their antibacterial effect.

It is.

That is, the present invention is a cylindrical antibacterial substance characterized by having an antibacterial metal component supported on the surface of acicular titanium dioxide and/or acicular potassium titanate.

In the present invention, the term acicular includes fibrous, columnar, rod-like, and other similar shapes.

In the present invention, the acicular titanium dioxide, which is the base particle supporting the antibacterial metal component, essentially has a composition of TiO2, and has an average major axis length of 1 μm or more, preferably 3 μm or more, The axial ratio (major axis/minor axis) is 3 or more, preferably 10 or more. Further, although the crystal form thereof is a rutile type, it may include a part of an anacoose type.

Acicular titanium dioxide is produced by mixing rutile TiO□ with an alkali metal salt such as sodium chloride and an oxy-phosphorus compound, and then heating the mixture at 725 to 1000°C, as described in Japanese Patent Publication No. 47-44974. Alternatively, as described in Japanese Patent Publication No. 4,548,370, a TiO□ source, a zinc compound, an alkali metal compound, and a phosphoric acid compound are mixed and fired. In addition, when acicular titanium dioxide is obtained as a mixture of long and short titanium dioxide, the long ones are sorted out by a classification process, and those with a weight average major axis length of 1 μm or more and an axial ratio of 3 or more are selected. It is preferable to use Further, it is generally desirable to use the acicular titanium dioxide obtained in this way after removing soluble salts by leaching with water or the like after calcination. Although it is difficult to completely remove soluble salts, the acicular titanium dioxide used in the present invention may contain small amounts of impurities.

Moreover, ≦1-state potassium titanate is K2O·nTio.

It is a needle-like substance having a composition represented by the formula (wherein n is 2 to 8), and there are crystalline and amorphous types, but either type can be used.

Acicular potassium titanate is disclosed in Japanese Patent Publication No. 42-2726, for example.
As described in No. 4, a mixture of a basic oxygen-containing alkali metal compound and an oxygen-containing titanium compound was
It is obtained by firing at ~900°C and purifying and separating the fired product. Various other manufacturing methods have been proposed, and acicular potassium titanate having an average major axis length of 1 to 100 μm and an axial ratio of 10 to 100 is usually obtained, although it varies depending on the manufacturing method.

Various metals can be used as the antibacterial metal supported on the acicular titanium dioxide and acicular potassium titanate, which are the base particles, and preferred examples include metal copper, metal copper,
Examples include various copper alloys such as Cu-Zn, Cu-5n, and Cu-Zn-P, metallic silver, and metallic zinc.
They may be supported alone or in combination of two or more. The amount of the metal component supported is usually 0.001 to 35% of the supported metal based on the weight of the base particles.
, preferably 0.01 to 30%. If the supported amount is too low than the above range, the desired antibacterial effect will not be achieved, and if it is too large, it will not be advantageous in terms of cost, and the dispersibility in the antibacterial properties imparting treatment medium, color tone, etc. will be impaired. It's easy to get lost. In the present invention, supporting the antibacterial metal on the base particles can be carried out by various methods, such as (1) adding a reducing agent to the metal ion aqueous solution containing the metal component, and further adding a buffer if necessary; A plating bath is prepared by adding various auxiliary agents such as a complexing agent and a PL + regulator, and the base particle powder is immersed in this plating bath and stirred for a predetermined period of time to transfer the metal ions onto the surface of the particles. A method of depositing the antibacterial metal by electroless plating, in which it is deposited as a film; (2) If they are attached to the surface of the base particle, the antibacterial metal component can be more efficiently deposited into a film, and a strong film with good adhesion can be easily formed. A method of loading the powder and an antibacterial metal powder into a dry or wet compaction grinding device such as a ball mill or an edge runner mill and mixing under pressure to support the antibacterial metal on the surface of the base particles; (3) antibacterial properties; A method of supporting antibacterial metals on the surface of base particles by thermally decomposing various organometallic compounds containing metal components, such as alkyl metal compounds and organometallic complex compounds, on the particle surfaces. Note that when carrying out the above-mentioned supporting treatment, it is desirable to carry out the process in an atmosphere of an inert gas such as nitrogen gas to prevent oxidation as much as possible.

The acicular antibacterial substance supported in the above manner can be added to a wide range of applications, such as paints, plastic moldings, paper, and fibers, by applying a seeding method known per se. , various industrial and household electrical equipment,
It has excellent performance in antibacterial treatment of furniture, interior decoration materials, packaging materials for tableware, medical and hygiene materials and equipment, environmental hygiene equipment and facilities, and also has features as a conductive material. What can be achieved is very industrially useful.

The present invention will be further explained by giving examples and comparative examples below.

〔Example〕

(Manufacture of acicular titanium dioxide) Titanium tetrachloride aqueous solution (TiO□: 200 g/j 30
Colloidal amorphous titanium hydroxide, which was precipitated by neutralization with an aqueous sodium hydroxide solution while maintaining the temperature at 70°C, was aged at 70°C for 7 hours to obtain a rutile-type fine titania sol. Titanium dioxide powder obtained by drying and pulverizing this sol
parts by weight, 40 parts by weight of sodium chloride, and 10 parts by weight of sodium metaphosphate were mixed and baked at 830°C for 3 hours. The obtained baked product was poured into water, stirred, filtered and washed to remove soluble salts. Thereafter, they were classified using a liquid cyclone and those with a long sleeve length of 3 to 6 μm were selectively recovered.

(Production of acicular potassium titanate) 57.7 g of the titanium dioxide powder used in the production of acicular titanium dioxide and anhydrous potassium carbonate were mixed into 20/TiO□
Mix thoroughly so that the molar ratio is 1/3, and the mixture is
It was molded into a disk shape under a pressure of 0.00 kg/c+n''.

The obtained compact was placed in an alumina crucible and fired at 980°C for 3 hours in an electric furnace. Then up to 600°C2
The temperature was lowered over time and the fired product was taken out.

This material was identified by X-ray diffraction and was essentially a single phase of potassium tetratitanate (K2O.4TiOz).

After coarsely crushing this calcined product, it was put into boiling water of 22, immersed and held for 3 hours with strong stirring to filter and separate the needles, then put into boiling water again, and the specific resistance of the filtrate was It was washed until it showed about 7000 Ωcm. (At this time, the molar ratio of 20/TiO2 to the washed material was 1/6.6.) Thereafter, it was heat-treated at 800°C for 3 hours. The obtained needles were identified by X-ray diffraction and were found to be essentially a single phase of potassium hexatitanate (K2O.6TiO□), with a thickness of 0.2 to 1 μm and an average length of The axial length was approximately 90 μm.

Example 1 250 g of the acicular titanium dioxide was suspended in water to prepare an aqueous slurry (244 g/i).

250m1 of said slurry! , and add 10 g of brass powder (Fukuda Metal Foil Powder Industry BRA-He T-200) to it.
After thorough mixing in a Henschel mixer, it was subjected to compression mixing for 240 minutes in a brass ball mill (mill internal volume 4j2.6+nmφ brass balls filled with 1 500 mff, slurry amount 250 m short, rotation speed 15 Orpm). After the ball mill treatment, the slurry was taken out, diluted and sedimented repeatedly to separate brass powder particles and acicular titanium dioxide. The slurry after fractionation was filtered, washed with water, and dried to obtain the target acicular antibacterial substance having a brass alloy supported on the surface of the base particles.

Example 2 In Example 1, 250 m of aqueous slurry of base particles
I! , inside, silver powder particles (Fukuda Metal Foil Industry ^gc-A)
The target acicular antibacterial substance with metallic silver supported on the surface of the base particles was prepared in the same manner as in the same example except that 10 g of O) was added and a porcelain ball mill and balls were used. I got it.

Example 3 In Example 1, the aqueous slurry of substrate particles 250+n
j! Inside, copper powder (width metal foil powder industry CU-AT-20
0) was added and treated in the same manner as in the same example except that a copper ball mill and balls were used to obtain the desired acicular antibacterial substance with metal copper supported on the surface of the base particles. Obtained.

Example 4 The same procedure as in Example 1 was repeated except that 250 g of acicular potassium ticunate was suspended in water instead of acicular titanium dioxide to obtain the desired acicular antibacterial properties.

Example 5 The desired acicular antibacterial substance was obtained in the same manner as in Example 2 except that an aqueous slurry of acicular potassium titanate was used instead of acicular titanium dioxide.

Example 6 The desired acicular antibacterial substance was obtained in the same manner as in Example 3, except that an aqueous slurry of acicular potassium titanate was used instead of acicular titanium dioxide.

Example 7 10 g of acicular titanium dioxide was preheated to 65° C. in a palladium sol solution (added sodium dodecylhenzensulfonate to a Pd-Cl 2 aqueous solution and reduced with NaBII) 500 mj! After stirring for 20 minutes, the particles were tilted and washed with water to deposit palladium on the surface of the acicular titanium dioxide particles. The thus pretreated acicular titanium dioxide powder was coated in a plating bath solution (copper sulfate 0.11
mol/f! ,, bormaldehyde 2.2 mol
/ j! , rososil salt 0.5 mol/j! , Na0II
1. Omol/1, Na2CO:+0
．． 25mol/j2, IEDTAO,06mo
1/1) (40° C.) and continued stirring at the same temperature for 40 minutes to deposit a metallic copper coating on the surface of the carrier particles. After that, the acicular titanium dioxide particles are separated by filtration, washed with water,
The target needle-shaped antibacterial substance was obtained by drying.

Example 8 The desired acicular antibacterial substance was produced in the same manner as in Example 7, except that 10 g of acicular potassium titanate powder was used in place of the acicular titanium dioxide powder. I got it.

Example 9 20 g of acicular titanium dioxide was mixed with 400 g of ethylene glycol.
After suspending in mj+, this suspension was placed in a four-hole flask equipped with a stirrer, and stirred for 30 minutes under a non-oxidizing atmosphere while introducing nitrogen gas.

Next, 6.7 g of Cu(C, 5l17oz) 2 was added, and stirring was continued for an additional 15 minutes. After that, heat this material up to 190°C (4°C/min), and
CLI (C5I1.0□)2 was thermally decomposed while holding for 0 minutes.

The suspension was then filtered and washed (washed with toluene) to obtain a cake. This cake was gently dried at a low temperature to obtain the target needle-shaped antibacterial substance with metallic copper supported on the particle surface.

Example 10 Example 9 except that 20 g of acicular potassium titanate powder was used instead of acicular titanium dioxide powder.
The desired acicular antibacterial substance having metallic copper supported on the particle surface was obtained by processing in the same manner as in the same example.

Test Example For the acicular antibacterial substance name Log obtained in Examples 1 to 10, acrylic resin (Dainippon Ink Acrylic) was added in a volume ratio of 1:1, and Toluev 20mff1 was added to a Red Devil paint shaker ( Internal volume 200mff,
Glass Peas 1. A coating liquid was prepared by mixing and dispersing the mixture in a 0mmφ filling).

This coating liquid was applied onto a PET film using a doctor blade. After it is dry to the touch, it is further dried at 80°C for 10 hours to obtain a coated product (s++ S2...S+o+ coating thickness 11
~14μm, total thickness 110-115μm, diameter 23mm
φ) was obtained.

s,, s3. created as described above. s...
s',.

S, coated product sample, So: untreated PET film, C
: Use a copper plate as a sample piece, put two of each sample piece (side-by-side) into a petri dish holding 100ml of sterile physiological saline added with 0.10% peptone, inoculate with a predetermined amount of bacteria, and immediately remove the bacteria. The antibacterial properties of each sample were evaluated by checking the number of bacteria under the culture temperature (35'C). The result is the first
Shown in the table. The following three types of bacteria were used in the test.

B+; E, Co11 (E. coli) B2
; S, tap, aureus (Staphylococcus)
11+; T, 5choenleini (
(Number of pieces added = 2) [Effects of the invention] The acicular antibacterial substance obtained by the present invention has an antibacterial metal component firmly supported on the surface of the base particles,
It can be expected to increase the durability of its antibacterial effect, and it also has the colorant properties of acicular titanium dioxide or acicular potassium titanate, such as high hiding power, coloring power, and dispersibility. It has great industrial utility value as an antibacterial treatment material and as a strength-laying material in a wide range of fields of use.

Claims (1)

[Claims] An acicular antibacterial substance characterized by having an antibacterial metal component supported on the surface of acicular titanium dioxide and/or acicular potassium titanate.