JP2000313817A - Resin additive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin additive which is mixed, together with an antimicrobial agent containing silver, zinc, or the like, into a resin molding containing an inorganic filler and which prevents the decrease in antimicrobial effects of the antimicrobial agent by using, as the additive, at least one salt selected from among carbonates, calcium salts and lithium salts. SOLUTION: At least one salt selected from among carbonates, calcium salts and lithium salts, preferably lithium carbonate, is mixed together with at least one antimicrobial agent containing silver, zinc, or the like into a resin molding containing an inorganic filler. The amount of the additive mixed is 0.5-10 wt.% of calcium carbonate contained in the filler. The antimicrobial agent is selected from among zeolite-, molten glass- and calcium phosphate-based antimicrobial agents. A resin molding containing an inorganic filler is made antimicrobial e.g. by incorporating a mixture comprising lithium carbonate and a powder of an antimicrobial agent containing silver, zinc, or the like, into the molding or by incorporating the antimicrobial agent with lithium carbonate fixed to the surface thereof into the molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an additive for increasing the antibacterial effect of a resin molded article containing an inorganic filler, particularly calcium carbonate, and a method thereof.

[0002]

2. Description of the Related Art In recent years, various attempts have been made to impart antibacterial properties to resin molded products. However, in the case of an inorganic filler, in particular, a resin molded product containing calcium carbonate, in order to obtain an antibacterial property by an antibacterial agent containing silver, zinc, etc., in order to sufficiently obtain the effect, It was necessary to increase the amount of the antimicrobial agent added as compared with the case of other fillers. In addition, the resin molded product has disadvantages such as discoloration and an increase in cost of the molded product as the amount of the antibacterial agent increases.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and shows a sufficient antibacterial effect by adding a small amount without reducing the antibacterial effect of an antibacterial agent containing silver, zinc, or the like. It is an object of the present invention to provide a resin additive that can be used. Further, by reducing the addition rate of the antibacterial agent, it is possible to avoid the risk of discoloration and to reduce the cost compared to conventional products.

[0004]

Means for Solving the Problems The resin additive of the present invention made in order to solve the above-mentioned problem is to provide a resin molded product containing an inorganic filler together with an antibacterial agent containing silver, zinc and the like, a carbonate,
It is characterized by mixing at least one of calcium salt and lithium salt. And it is desired to use especially lithium carbonate among carbonate, calcium salt, and lithium salt. In addition to the above salts, it is preferable to use a soluble glass that contains calcium and / or lithium in the soluble glass and can elute calcium ions and / or lithium ions in water. Further, the antibacterial agent containing silver, zinc or the like is preferably at least one selected from a zeolite type, a molten glass type, and a calcium phosphate type. The present invention is particularly effective when the inorganic filler contains calcium carbonate. In this case, the mixing ratio of lithium carbonate is preferably 0.5 to 10% by weight based on the weight of calcium carbonate.

[0005] The method for imparting antibacterial effect to a resin molded product of the present invention is a method of adding a simple mixture of a powder of an antibacterial agent containing silver and zinc and lithium carbonate to a resin molded product containing an inorganic filler. In some cases, lithium carbonate is fixed to a surface of an antibacterial agent containing silver, zinc, or the like and fixedly mixed with a resin molded article containing an inorganic filler, and then added. At the time of immobilization on the inorganic filler, lithium carbonate may be preliminarily immobilized at a high concentration of a specified amount or more, and then diluted and used.

[0006]

Embodiments of the present invention will be described below in detail. A resin molded article containing an inorganic filler is mixed with an antibacterial agent containing silver, zinc, or the like and one or more of a carbonate, a calcium salt, and a lithium salt. Among salts and lithium salts, use of lithium carbonate is advantageous in terms of antibacterial effect. Further, the effect is high when the inorganic filler contains calcium carbonate. That is, it is considered as follows that the antibacterial effect is increased by mixing lithium carbonate. Calcium carbonate in the resin is

[0007]

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Dissociates as follows. The dissociated carbonate ion reacts with a metal ion, for example, a silver ion, which is an antibacterial component of the antibacterial agent, and precipitates as silver carbonate. Therefore, the antibacterial effect is reduced.

[0009]

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The lithium carbonate to be mixed dissociates in water as follows.

[0011]

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When the dissociation of the equation (3) occurs in the equation (1), the reaction proceeds to the left according to Le Chatelier's principle in the equation (1), which is a weak electrolyte. Since the lithium ions dissociated in the formula (3) attract the carbonate ions dissociated in water very strongly, the attracted carbonate ions cannot react with other ions.

Looking at these phenomena comprehensively, carbonate ions decrease as equation (1) proceeds to the left. Since carbonate ions generated by dissociation of lithium carbonate have no reactivity under the influence of lithium ions, the number of reactive carbonate ions decreases as a result. As a result, the carbonate ion in the formula (2) decreases, and the reaction proceeds to the left. Therefore, it is presumed that the antibacterial effect is increased because silver ions which have been precipitated as silver carbonate exist in water in an ion state.

When the mixing ratio of lithium carbonate is 0.5 wt% or less based on the weight of the inorganic filler, the antibacterial effect of the antibacterial agent cannot be improved. If added in an amount of 10 wt% or more, the resin may be deteriorated. Preferably, 1.5 to 5 wt% is good.

In addition to the above salts, it is preferable to use a soluble glass which contains calcium and / or lithium in the soluble glass and can elute calcium ions and / or lithium ions in water. Further, the antibacterial agent containing silver, zinc or the like is preferably at least one selected from a zeolite type, a molten glass type, and a calcium phosphate type.

The method for imparting antibacterial activity in the present invention includes a method of adding a powder of an antibacterial agent containing silver / zinc and the like and lithium carbonate to a resin molded product containing an inorganic filler by simply mixing them. A method in which lithium carbonate is fixed and mixed with a binder on the surface of an antibacterial agent containing silver, zinc, or the like in a resin molded product containing a system filler, and then added,
At the time of immobilization on the inorganic filler, lithium carbonate may be preliminarily immobilized at a high concentration of a specified amount or more, and then diluted and used.

[0017]

Examples are shown below. As shown in Table 1, for each of Examples 1 to 7 and Comparative Examples 1 and 2, calcium carbonate was used as an inorganic filler, and an antibacterial agent powder and lithium carbonate, calcium hydroxide, lithium sulfate, and potassium carbonate were respectively used for a resin molded product. , And sodium chloride. Among them, in Example 6, lithium carbonate was fixed to three times the specified amount of calcium carbonate, diluted and added. Example 7 used a fusing glass containing calcium and lithium. In addition, the antibacterial agent is shown by weight% with respect to the resin + filler, and the lithium carbonate, sodium carbonate, potassium carbonate and sodium chloride are shown by weight% with respect to the filler.

[0018]

[Table 1]

In the antibacterial test, a resin plate formed by each preparation was used as a sample, a solution containing Escherichia coli was dropped on the sample, left at 35 ° C. for 24 hours, the bacterial solution was washed out, and the number of viable bacteria was measured. Note that the sterilization rate indicates the ratio of the killed bacteria after 24 hours from the start. Table 2 shows the results.

[0020]

[Table 2]

As described above, a sufficient antibacterial effect is exhibited by mixing lithium carbonate with a resin containing calcium carbonate.

[0022]

The antibacterial effect of the antibacterial agent has been reduced by the inorganic filler, and the addition rate has been increased to compensate for it. However, the addition of lithium carbonate increases the antibacterial effect of the antibacterial agent. A sufficient antibacterial effect can be exhibited while suppressing the addition rate of the antibacterial agent. Therefore, the present invention has a high value as a resin additive that has eliminated the conventional problems, and there are some that greatly contribute to the industry.

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Claims (9)

[Claims] 1. A resin molded product containing an inorganic filler, a carbonate, a calcium salt, an antibacterial agent containing silver, zinc, etc.
A resin additive characterized by mixing at least one or more lithium salts. 2. The resin additive according to claim 1, wherein lithium carbonate is used among carbonates, calcium salts and lithium salts. 3. In addition to the above salts, a soluble glass containing calcium and / or lithium in the soluble glass and capable of eluting calcium ions and / or lithium ions in water is used. The resin additive according to claim 1 or 2. 4. The antibacterial agent containing silver, zinc or the like is at least one selected from the group consisting of zeolite, molten glass, and calcium phosphate. 3. The resin additive according to 3. 5. The resin additive according to claim 1, wherein the inorganic filler contains calcium carbonate. 6. The resin additive according to claim 5, wherein the mixing ratio of lithium carbonate is 0.5 to 10% by weight based on the weight of calcium carbonate. 7. A method for imparting antibacterial effect to a resin molded product, which comprises simply adding a powder of an antibacterial agent containing silver, zinc or the like and lithium carbonate to a resin molded product containing an inorganic filler and mixing them. 8. A resin molding, characterized in that lithium carbonate is fixed to a surface of an antibacterial agent containing silver, zinc, etc. using a binder, fixedly mixed, and added to a resin molded product containing an inorganic filler. How to impart antibacterial to products. 9. A method for imparting antibacterial effect to a resin molded product, wherein lithium carbonate is fixed in a high concentration of a specified amount or more in advance and then diluted before immobilization on an inorganic filler.