JPH0532407A - Antibacterial phosphate intercalation complex - Google Patents

Abstract

PURPOSE:To provide the subject complex having antibacterial effect on a variety of bacteria, little in discoloration with time in itself while retaining such advantages as antibacterial persistence, antibacterial stability and heat resistance, and when used also as an antibacterial resin composition obtained by its kneading with a resin, showing only little discoloration by its kneading and the discoloration with time of said composition after kneading. CONSTITUTION:The objective complex consisting of a laminar phosphate intercalated with alkali metal ion and antibacterial metallic ion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel antibacterial phosphate intercalation compound having an antibacterial activity against various bacteria. More specifically, it does not discolor itself with time and is kneaded with a resin or the like. Also when used as an antibacterial resin composition,
The present invention relates to an antibacterial phosphate intercalation compound in which discoloration during kneading with a resin and further discoloration over time of the antibacterial resin composition after kneading are small.

[0002]

2. Description of the Related Art Conventionally, in an inorganic antibacterial agent, a metal such as silver having an antibacterial effect or a compound thereof has been adsorbed on an adsorbent such as zeolite, activated carbon, activated alumina or silica gel and used for antibacterial purposes. It has been known. In addition, various organic substances have been proposed as organic antibacterial agents. However, the former inorganic type has a problem in terms of durability of antibacterial effect due to insufficient stability of antibacterial metal such as silver. Further, the latter organic system has drawbacks such as poor heat resistance, high vapor pressure, and relatively high toxicity.

As one of the solutions to such problems of conventional antibacterial agents, an antibacterial composition obtained by supporting heavy metal ions on a phosphate or condensed phosphate which is insoluble or sparingly soluble in water. Has been proposed (JP-A-2-965).
08). In this antibacterial composition, a metal having an antibacterial effect is stably retained in an active state, and the antibacterial effect is excellent in durability and heat resistance.

[0004]

However, when the above-mentioned antibacterial composition is used as an antibacterial resin composition by kneading with a resin or the like, the antibacterial resin discolors during kneading with the resin, or the antibacterial resin after kneading is used. There is a problem that the composition gradually changes color over time.

Therefore, in the present invention, when the antibacterial resin composition does not discolor itself with time and is further kneaded with a resin or the like to be used as an antibacterial resin composition, the antibacterial resin composition after kneading has a color change during kneading. The purpose of the present invention is to provide an antibacterial interphosphate compound that does not gradually change color over time.

[0006]

That is, the antibacterial phosphate intercalation compound of the present invention comprises a layered phosphate in which a metal ion having an antibacterial action and an alkali metal ion are intercalated by an ion exchange method. It is a feature. This antibacterial phosphate intercalation compound does not lose its many advantages such as durability of antibacterial effect, stability of antibacterial substance, and heat resistance, and it does not discolor itself with time, and is kneaded with a resin or the like. Also when used as an antibacterial resin composition, discoloration during kneading with a resin and further discoloration with time of the antibacterial resin composition after kneading are small.

The above-mentioned antibacterial phosphate intercalation compound of the present invention is obtained by bringing a layered phosphate into contact with an aqueous solution of a metal having an antibacterial action and an alkali metal to perform ion exchange.
Easy to manufacture.

As the metal ion having an antibacterial action used in the present invention, silver ion, copper ion, zinc ion and the like can be preferably used, and not only one kind but also several kinds of these metal ions are intercalated in the layered phosphate. You may let me. As the alkali metal ion, lithium ion, sodium ion and the like are preferably used, and not only one kind but also several kinds may be intercalated into the layered phosphate.

As the layered phosphate serving as a support for metal ions having an antibacterial action and alkali metal ions, phosphates of tetravalent metals such as zirconium phosphate and titanium phosphate, and aluminum tripolyphosphate can be preferably used. . Tetravalent metal phosphates are available from A. Clearfield, G. Albe
rti and U. Costantino “Inorganic Ion Exchange Mat
erials ", A. Clearfield ed, CRC Press, Inc., USA, although compendium is described in Chapter 3 (1982), M ⁴ (HP
O ₄ ) ₂ . It is represented as nH ₂ O (M ⁴ ; tetravalent metal) and is generally well known such as monohydrate α-type and dihydrate γ-type. These are solid acids that are sparingly soluble in water and have cation exchange ability. The ion exchange capacity is based on the hydrogen phosphate group (HPO ₄
^2- ) protons, and the theoretical ion exchange capacity is 6.64 meq / g for α-type zirconium phosphate (hereinafter abbreviated as α-ZrP) and α-type titanium phosphate (hereinafter α-Ti).
7.76 meq / g, γ-type zirconium phosphate (hereinafter abbreviated as γ-ZrP) 6.27 meq / g,
γ-type titanium phosphate (hereinafter abbreviated as γ-TiP) is 7.25.
It is meq / g. Aluminum tripolyphosphate is represented by AlH ₂ P ₃ O ₁₀ · 2H ₂ O (hereinafter abbreviated as AlP), and has a theoretical ion exchange capacity of 6.29 meq / g.
Is.

The reaction in which the metal ion having an antibacterial action and the alkali metal ion intercalate the layered phosphate is considered to be an ion exchange reaction with the proton of the hydrogen phosphate group. In the production of the antibacterial phosphate intercalation compound of the present invention, a part or all of the ion-exchangeable protons of the above-mentioned layered phosphate are converted by an ion exchange method into a metal ion and an alkali metal ion having an antibacterial action. It can be carried out at room temperature to high temperature by a general batch method or column method. As described above, after intercalating metal ions and alkali metal ions having antibacterial action into layered phosphate by ion exchange, the solid phase is filtered and washed with water to remove unreacted ions and then dried. Thereby, a layered phosphate in which a metal ion having an antibacterial action and an alkali metal ion are intercalated, that is, an antibacterial phosphate intercalation compound is obtained.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples, but this example is merely for illustrative purposes.
The invention is not limited by these examples.

Example 1 (Method for Producing Antibacterial Phosphate Intercalation Compound of the Present Invention) For 20 g of a layered phosphate, a metal nitrate (AgNO ₃ , Cu (NO) having an antibacterial action having the composition shown in Table 1 was used. ₃ )
₂ , Zn (NO ₃ ) ₂ ) aqueous solution (400 ml) is added, and then a predetermined amount (shown in Table 1) of an aqueous solution of alkali metal hydroxide (LiOH, NaOH) is gradually added with stirring, and the mixture is stirred for about 4 hours. Continued contact. Thus, the metal ion having an antibacterial action and the alkali metal ion were intercalated in the layered phosphate. Next, the solid phase is separated by filtration and washed with water 1
It was dried at 00 to 110 ° C for about 5 hours to obtain the antibacterial phosphate intercalation compound of the present invention.

Comparative Example 1 (Conventional Method for Producing Antibacterial Composition Not Containing Alkali Metal Ion) An alkali metal hydroxide was prepared by using 400 ml of an aqueous solution of a metal salt of a metal having the composition shown in Table 1 and having an antibacterial effect. In the same manner as in Example 1 except that the aqueous solution of
A conventional antibacterial composition containing no alkali metal ion was prepared.

The contents of the metal ions and the alkali metal ions having the antibacterial action of the samples prepared in Example 1 and Comparative Example 1 are shown in Table 2.

Example 2 (Antibacterial Test) The minimum inhibitory concentration (hereinafter abbreviated as MIC) against various bacteria of the antibacterial composition obtained in Example 1 and Comparative Example 1 was measured by an agar dilution method. The measurement was performed in the following manner:

On a sterile petri dish, 10 ml of ordinary agar medium containing different concentrations of the antibacterial composition is prepared. A fixed amount of the test bacterial solution is placed on each of these media, dried and cultured at 30 ° C. Then, when there is no change (growth or decrease) in the state of the bacterium, the minimum concentration (MIC) of the concentration of the antibacterial composition is determined from the medium in which the growth is completely inhibited. Staphylococcus aureus (Staphylococcus aureus), Escherichiacoli (Escherichia coli), Bacillus subtil
is (Bacillus subtilis) and Pseudomonas aeruginosa (Pseudomonas aeruginosa) were used.

The results are shown in Table 3. It can be said that the smaller the MIC value is, the stronger the antibacterial activity is, but it can be seen that the antibacterial activity is equal to that of the conventional product.

Example 3 (Discoloration test) The discoloration test was carried out by the following method: (Resin kneading discoloration test) Each of the samples obtained in Example 1 and Comparative Example 1 was added to 100 parts of low-density polyethylene powder. 5
Parts and 5 parts of titanium oxide were added, mixed well, and heated and melted in a crucible at 190 ° C. for 20 minutes. After cooling and after 50 hours of light irradiation using a fade odometer, the color changes were compared. The color is expressed by the Munsell value in comparison with the Munsell color chart. The results are shown in Table 4.

(Discoloration test of the antibacterial phosphate intercalation compound itself) The change in color immediately after the preparation and after 50 hours of light irradiation with a fade odometer were compared. The color was represented by the Munsell value as in the resin kneading test. The results are shown in Table 5.

[0020]

The antibacterial phosphate intercalation compound of the present invention is
An antibacterial resin composition having the same level of antibacterial activity as a conventional antibacterial composition containing no alkali metal ion, and discoloration over time compared to conventional products or discoloration when kneaded with a resin or the like and after kneading Much less color change over time (see Tables 4 and 5).

Also, in producing the antibacterial phosphate intercalation compound of the present invention, it has an alkali metal ion and an antibacterial action as compared with the method of intercalating only the metal ion having an antibacterial action into the layered phosphate. Simultaneous ion exchange with metal ions improves the yield of metal ions having an antibacterial effect (see Table 1 and Table 2).

[0022]

[0023]

[0024]

[0025]

[0026]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C01D 1/00 9041-4G C08K 3/32 KAG 7167-4J 9/02 KCN 7167-4J

Claims (2)

[Claims] 1. An antibacterial phosphate intercalation compound comprising a layered phosphate in which an alkali metal ion and a metal ion having an antibacterial action are intercalated. 2. The metal ion having an antibacterial effect is selected from silver ion, copper ion or zinc ion.
The antibacterial phosphate intercalation compound according to.