JP2836626B2 - Manufacturing method of antibacterial resin molded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a resin molded product having antibacterial properties on its surface, such as a resin product used in various industrial fields and its material. Specifically, a resin in a fluid state to which an antimicrobial agent represented by an ion exchanger (zeolite or ion exchange resin) to which metal ions (silver ion, zinc ion, copper ion, tin ion, etc.) are added is molded. By doing
The present invention relates to a method for producing a resin molded product having antibacterial properties on the surface.

[Conventional technology]

In the above-mentioned resin molded article having antibacterial properties on the surface, that is, in the case of antibacterial resin molded articles, when microorganisms such as bacteria adhere to the surface, the adhered microorganisms can be killed or reproduction can be stopped. it can. Therefore, especially in the pharmaceutical industry, food industry, equipment for the production of electronic device industry, etc., pharmaceutical equipment, sanitary equipment, etc., it is required to be able to prevent or suppress the growth and propagation of microorganisms, or under favorable environment and conditions It is very suitable as a resin product used in the above or a material thereof.

Conventionally, in producing such an antibacterial resin molded product, the added antibacterial agent is uniformly distributed by stirring the resin in a fluid state such as a molten state or a liquid state.

[Problems to be solved by the invention]

However, the conventional method has the following disadvantages.

That is, since the antibacterial agent is mixed with the resin in a fluid state, the entire surface of the antibacterial agent is covered with the resin.
When a resin in a fluid state containing such an antibacterial agent is molded into a predetermined shape by a mold, the resin in a fluid state may flow along the surface of the mold on a surface in contact with the mold. Antimicrobial agents are very rarely exposed on the surface. In particular, when a liquid thermosetting resin is poured into a mold or the like and molded, the resin gradually cures from the surface side, and it takes some time until the entire resin is cured. Therefore, in the case of an antibacterial agent having a specific gravity higher than that of a resin, such as an ion exchanger bonded to a metal ion, the antibacterial agent settles in the resin for a time until the curing is completed. Therefore, when looking at the distribution of the antibacterial agent in the molding resin, the amount of the antibacterial agent exposed on the upper surface becomes very small. In addition, when a resin molded article is formed by extrusion molding or injection molding of a polyolefin resin such as polyethylene or polypropylene, or a thermoplastic resin such as polyvinyl chloride resin, a molten resin that is in a fluid state in a molding process is used in a mold. By being pressed against the surface and sliding, the antibacterial agent is pushed into the resin, and the amount of the antibacterial agent exposed on the surface is extremely small. This tendency increases as the viscosity of the resin decreases.

As a result, when using the conventional method, particularly when using a resin having a low melting point and low viscosity, the amount of the added antibacterial agent is:
It was difficult to impart sufficient antibacterial properties to the surface of the molding resin. In other words, in order to impart sufficient antibacterial properties to the surface of the molding resin, an unnecessarily large amount of antibacterial agent is required, and a cost increase cannot be avoided.

An object of the present invention is to provide a method capable of producing a resin molded product having a sufficient antibacterial property on the surface while using a small amount of an antibacterial agent.

[Means for solving the problem]

The features of the method for producing an antibacterial resin molded product according to the present invention include:
A method of producing a resin molded product having antibacterial properties on the surface by molding a resin in a fluid state to which an antibacterial agent composed of zeolite powder having metal ions bonded thereto is added. The present invention is characterized in that beads blast processing is performed on a portion to be provided with antibacterial property on the surface.

(Operation)

In the molding resin, although the antibacterial agent exposed on the surface is small, the antibacterial agent is distributed in a portion very close to the surface at a density commensurate with the added amount. In the present invention, to remove the surface of the molding resin after molding, by adjusting the removal depth according to the melting point and viscosity of the resin, the surface layer of the molding resin having a small antibacterial agent density is reduced. By removing the surface, it is possible to provide a surface on which an antibacterial agent having a density higher than that of the antibacterial agent is distributed. At this time, since the resin is removed by bead blasting, the resin having a lower hardness than the zeolite is preferentially removed, so that the antibacterial agent tends to protrude as shown in FIG. The antimicrobial agent is hardly detached, and the antibacterial property can be efficiently enhanced.

〔The invention's effect〕

As a result, according to the present invention, a surface that exposes antibacterial properties with a distribution density and a dispersion state sufficient to express sufficient antibacterial properties is provided without causing an unjustified cost increase due to an increase in the amount of the antibacterial agent used. Thus, it has become possible to provide a method for producing an antibacterial resin molded product.

In addition, bead blasting makes it easier to perform blasting with a uniform particle size than other blasting processes, and it is easier to uniformly scrape the surface of the part of the molding resin to which antibacterial properties are imparted, and to improve antibacterial properties efficiently. Especially effective.

〔Example〕

 Next, examples of the present invention will be described.

A method of producing an antibacterial resin molded article having antibacterial properties on the surface by molding a resin in a fluid state to which an antibacterial agent has been added. Deletion processing is performed on the portion to be given.

The antibacterial agent is a fine particle having a particle diameter of about 0.1 to 3 μm obtained by binding a metal ion to an ion exchanger. The ion exchanger is a synthetic zeolite, a natural zeolite, or the like,
The metal ions are silver ions, copper ions, tin ions, zinc ions, and the like. It is a well-known fact that such an antibacterial agent has an antibacterial ability that kills the contacted microorganism or stops its reproductive ability by contact with a microorganism such as bacteria (bacteria). .

Examples of the resin include various thermoplastic resins such as a polyolefin resin (eg, polyethylene and polypropylene), a polyvinyl chloride resin, an acrylonitrile butadiene resin (ABS resin), an unsaturated polyester resin, a polyether resin, a fluororesin, and an epoxy resin. A thermosetting resin can be used.

The amount of the antibacterial agent to be added may be at least 4% by weight of the resin, but is preferably about 4 to 10% in view of the balance between the antibacterial property and economy.

As a means for preparing a resin in a fluid state to which the antimicrobial agent is added in a predetermined amount, (A) after adding a predetermined amount of the antimicrobial agent to a powdery or pallet-shaped resin raw material and mixing, melting the resin raw material, Means for stirring, [B] means for adding a predetermined amount of an antibacterial agent to a molten resin or a liquid thermosetting resin raw material and stirring and mixing, [C] in the above [A], a dispersant is previously used as an antibacterial agent [D] In the above [B], a dispersant is added to the resin material in a fluid state together with the antibacterial agent, or a dispersant is previously added and mixed as the antibacterial agent. [E] In the above [A], a predetermined amount or more of an antibacterial agent is added to first prepare an original resin raw material containing a predetermined amount or more of an antimicrobial agent, and then a resin not containing the original resin raw material and an antibacterial agent is prepared. The amount of antibacterial agent to be added Means such as mixing by adjusting the mixing ratio physician so that can be given.

In the above [C] and [D], the amount of the dispersant added is about 10% by weight of the antibacterial agent, and in the above [E], the amount of the antibacterial agent in the original resin raw material is the same as the original resin raw material in weight. 20% of
That is all.

In the case of [C] and [D], the antibacterial agent can be evenly dispersed in the molding resin. In the case of [E], the antibacterial agent and the resin can be dispersed by increasing the amount of the antibacterial agent. In order to improve the conformity with the resin, it can be evenly dispersed in the molding resin.

Injection molding,
Examples include extrusion molding, press molding, hand lay-up molding, centrifugal molding, and FW molding.

In general, in the molding resin, the antibacterial agent is covered with the resin in a fluid state, and the resin in the fluid state flows into a portion in contact with a mold surface.
As shown in (b), the surface layer portion (1A) of the molding resin (1) does not contain the antimicrobial agent (2) or the content of the antimicrobial agent (2) is small, and the surface layer portion (1A)
A) A portion sufficiently containing the antibacterial agent (2) is formed below. The thickness of the surface layer (1A) is determined by the melting point and viscosity of the resin,
Although it varies depending on the specific gravity difference between the antibacterial agent and the resin, it is generally several microns for a low-melting-point, low-viscosity polyolefin resin such as polyethylene or polypropylene.

Therefore, when the surface layer portion (1A) is formed with the molding resin, the antibacterial agent (2) exposed on the surface (1a) of the molding resin is very small or not present, so that sufficient antibacterial properties (antibacterial activity) are obtained. A) with a surface.

As shown in FIG. 2, the removal processing is for shaving off the surface layer (1A) and exposing the antibacterial agent (2) under the surface layer (1A) to the surface. As a specific means, bead blasting can be mentioned.

Next, experimental examples performed by the present inventors to confirm the usefulness of the method of the present invention will be described.

Experimental Example 1 A zeolite powder (particle diameter: about 3 μm) bound with silver ions was prepared as an antibacterial agent, and three resin materials, a polyethylene resin, a polypropylene resin, and a polyvinyl chloride resin, were prepared as resin raw materials. And from each of the three resin raw materials,
A resin piece containing 4% and 6% of antibacterial agent is made by injection molding,
Each of the resin pieces was divided into two parts, and one of the surfaces was subjected to deletion processing by peas blasting to produce a test piece with deletion processing and a test piece without deletion processing. Among the resin pieces, those using a polyethylene resin and a polypropylene resin as a resin raw material are prepared by the method of [E] described above, and those using a polyvinyl chloride resin as a resin raw material are obtained by the method of [C] described above. Produced. In addition, in the method [E], the amount of the antibacterial agent of
In the method [C], an antibacterial agent to which a dispersing agent of 10% was added and mixed was added to the polyvinyl chloride resin and melted.

Then, a bacterial solution containing 10 ⁷ cell / ml of Escherichia coli was prepared, and 1 ml of the bacterial solution was dropped on the surface of each test piece. After placing at 25 ° C. for 18 hours, an antibacterial confirmation test for counting the number of bacteria was performed. . Table 1 shows the results.

As is clear from Table 1, for each resin,
It has been found that the number of bacteria can be reduced by one digit when the deletion processing is performed compared to the non-processing, and the antibacterial property can be improved according to the method of the present invention.

Experimental Example 2 The same antibacterial agent as in the above example was prepared, and an unsaturated polyester resin was prepared as a resin raw material. The unsaturated polyester resin added with 2%, 4%, 6% and 10% of the antibacterial agent The liquid was prepared. Then, as shown in FIG. 3, a glass framing mat is placed on a metal plate (3) coated with a release agent, and a mixed unsaturated polyester resin (4) to which an antibacterial agent has been added is added to a thickness of about 1 mm. After coating, and then placing a glass chopped strand mat on top of it, applying an anti-microbial-free unsaturated polyester resin (5) to a thickness of about 10 mm and curing it, then peeling off the resin layer from the metal plate A resin piece is manufactured, each of the resin pieces is divided into two parts, and the surface of the resin layer to which the antibacterial agent is added in one of the pieces is subjected to bead blasting processing, and a test piece with a deleted processing and a deleted processing are performed. And the test piece without it. Note that three sets of test pieces were produced.

Then, the same antibacterial test as in Experimental Example 1 was performed on each test piece.

 Table 2 shows the results.

As is clear from Table 2, it was found that the antibacterial property can be improved.

[Brief description of the drawings]

The drawings show an embodiment of the method for producing an antibacterial resin molded product according to the present invention. FIGS. FIG. 3 is a cross-sectional view of the molding resin after the removal processing, and FIG. 3 is a cross-sectional view showing the resin molding method in the second embodiment. (A): antimicrobial agent; (1): molding resin; (1a): surface.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsunobu Masuda 1-3-3-23 Dojimahama, Kita-ku, Osaka-shi, Osaka Prefecture Inside Takuma Co., Ltd. (72) Inventor Nobuyuki Tanaka 1-3-23 Dojimahama, Kita-ku, Osaka-shi, Osaka No. TAKUMA CORPORATION (72) Inventor Goro Fujiwara 1-33-23 Dojimahama, Kita-ku, Osaka-shi, Osaka Prefecture TAMACHI CORPORATION (72) Inventor Shinya Matsumoto 1023-1 Yamazaki, Oshima, Mishima-gun, Osaka Suntory Shares (72) Inventor Hiroaki Sasaki 1023-1 Oaza Yamazaki, Shimamoto-cho, Mishima-gun, Osaka Prefecture Suntory Ltd. Technology Development Center (72) Taiji Tsubota 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka Suntory Limited Research Center (72) Inventor Kiyoshi Miura 41-3 Higashikujo Nishikawabecho, Minami-ku, Kyoto-shi, Kyoto (72) Inventor Kunihiko Nakai 90 Maeda, Fuji City, Shizuoka Prefecture Inside Fuji Kako Co., Ltd. (56) Reference JP-A-63-209656 (JP, A) JP-A-60-174802 (JP, A) JP-A 62-241939 (JP) , A) JP-A-2-243159 (JP, A) JP-A-1-294470 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 67/00-71/00

Claims (1)

(57) [Claims] 1. A method for producing a resin molded article having an antibacterial property on a surface by molding a resin in a fluid state to which an antibacterial agent comprising zeolite powder to which metal ions are bound is added. A method for producing an antibacterial resin molded product in which bead blasting is performed on a portion to be provided with antibacterial activity on the surface of the molding resin.