JPH02293123A - Manufacture of antibacterial resin molding - Google Patents

Abstract

PURPOSE:To obtain a resin molding the surface of which is provided with sufficient antibacterial properties even while reducing consumption of an antibacterial agent, by a method wherein after molding of resin where the antibacterial agent is added to the same and the same is in a fluidized state, elimination processing of an objective part for giving of the antibacterial properties out of the surface of the molding resin is performed. CONSTITUTION:A fluid resin 1 to which antibacterial agent is added is molded. Then the antibacterial agent 2 underneath a surface layer part 1a is exposed to the surface by scraping off the surface layer part 1a of the molded resin 1 and a resin molding having sufficient antibacterial properties on the surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing resin molded products having antibacterial properties on their surfaces, such as resin products and their materials used in various industrial fields. Specifically, we mold resin in a fluid state to which an antibacterial agent is added, typically an ion exchanger (zeolite, ion exchange resin, etc.) to which metal ions (e.g., ion, zinc ion, copper ion, tin ion, etc.) are added. The present invention relates to a method for producing a resin molded product having antibacterial properties on its surface.

[Conventional technology]

With the above-mentioned resin molded products with antibacterial properties on the surface, in other words, antibacterial resin molded products, if microorganisms such as bacteria adhere to the surface, it is possible to kill the attached microorganisms or stop their reproduction. can. Therefore, production equipment, medical equipment, sanitary equipment, etc. in the pharmaceutical industry, food industry, electronic device industry, etc. are required to be able to prevent or suppress the growth and propagation of microorganisms, or under favorable environments and conditions. It is very suitable for resin products used in and as a material for them.

Conventionally, to produce such antibacterial resin molded products,
The added antibacterial agent was evenly distributed by stirring the resin in a fluid state such as a molten state or a liquid state.

[Problem to be solved by the invention]

However, the conventional method has the following drawbacks.

In other words, since the antibacterial agent is mixed into the resin in a fluid state, the entire surface of the antibacterial agent is covered with the resin. When fluidized resin mixed with such an antibacterial agent is molded into a predetermined shape using a mold, the fluidized resin may flow along the surface of the mold on the surface that comes into contact with the mold. Antimicrobial agents are rarely exposed on surfaces.

In particular, when a liquid thermosetting resin is poured into a mold or the like and molded, the resin gradually hardens from the surface side, and it takes a certain amount of time for the entire resin to harden. Therefore, in the case of an antibacterial agent having a specific gravity greater than that of the resin, such as an ion exchanger bonded to metal ions, the antibacterial agent settles in the resin for a period of time until curing is completed. Therefore, when looking at the distribution of the antibacterial agent in the molded resin, very little of the antibacterial agent is exposed on the upper surface. In addition, when forming resin molded products by extrusion molding or injection molding polyolefin resins such as polyethylene, polypropylene, or thermoplastic resins such as polyvinyl chloride resin, the molten resin in a fluid state is molded into the mold during the molding process. By sliding against the surface, the antibacterial agent is pushed into the resin, and very little of the antibacterial agent is exposed on the surface. This tendency is greater as the viscosity of the resin is lower.

As a result, when using conventional methods, it is difficult to impart sufficient antibacterial properties to the surface of the molded resin, considering the amount of antibacterial agent added, especially when using a resin with a low melting point and low viscosity. In other words, in order to impart sufficient antibacterial properties to the surface of the molded resin, a larger amount of antibacterial agent than necessary is required, which inevitably increases costs.

The purpose of the present invention is to reduce the amount of antibacterial agents used while
The object of the present invention is to provide a method for producing a resin molded product having sufficient antibacterial properties on the surface.

[Means to solve the problem]

The feature of the method for producing an antibacterial resin molded article according to the present invention is that after molding the resin in a fluid state to which an antibacterial agent has been added, a deletion process is performed on the portion of the surface of the molded resin to which antibacterial properties are to be imparted. .

[For production]

In a molded resin, only a small amount of antibacterial agent is exposed on the surface, but the antibacterial agent is distributed in areas very close to the surface at a density commensurate with the amount added.

In the present invention, since the surface of the molded resin is removed after molding, the removal depth is adjusted according to the melting point and viscosity of the resin, so that the surface layer of the molded resin where the density of the antibacterial agent is low is removed. By removing the antibacterial agent, it is possible to obtain a surface having a high density distribution of the antibacterial agent commensurate with the amount of the antibacterial agent added.

〔Effect of the invention〕

As a result, according to the present invention, an antibacterial agent having a surface that exposes antibacterial properties with a distribution density sufficient to exhibit sufficient antibacterial properties can be obtained without causing an unreasonable cost increase due to an increase in the amount of antibacterial agents used. We are now able to provide a method for producing resin molded products.

〔Example〕

Next, examples of the present invention will be shown.

A method for producing an antibacterial resin molded product having an antibacterial property on the surface by molding a fluidized resin to which an antibacterial agent has been added. Perform deletion processing on the part to be added.

The antibacterial agent is fine particles having a particle size of about 0.1 to 3 μm, which are made by bonding metal ions to an ion exchanger. The ion exchanger is an ion exchange resin, a synthetic zeolite, a natural zeolite, etc., and the metal ions are silver ions, copper ions, etc.
These include tin ions and zinc ions. It is a well-known fact that such antibacterial agents have the antibacterial ability to kill microorganisms such as bacteria or stop their reproductive ability when they come into contact with them. .

The resins include various types of heat-resistant resins such as polyolefin resins (polyethylene, polypropylene, etc.), polyvinyl chloride resins, acrylonitrile butadiene resins (8BS resins), unsaturated polyester resins, polyether resins, fluororesins, epoxy resins, etc. Mention may be made of plastic and thermosetting resins.

The amount of the antibacterial agent added may be at least 4% by weight of the resin, but from the viewpoint of both antibacterial properties and economic efficiency, it is preferably about 4 to 10%.

The means for producing a resin in a fluid state to which a predetermined amount of the antibacterial agent has been added is as follows: (A) Adding and mixing a predetermined amount of an antibacterial agent to a resin raw material in powder or pallet form, and then melting the resin raw material; CB) means for adding a predetermined amount of antibacterial agent to the melted resin or liquid thermosetting resin raw material and stirring and mixing; (C) in (A) above, a dispersant is added in advance as the antibacterial agent; (D) In (B) above, the dispersant is added to the resin raw material in a fluidized state together with the antibacterial agent.
Alternatively, a means of using a dispersant mixed in advance as an antibacterial agent; (E) In (A) above, a predetermined amount or more of an antibacterial agent is added to make the original resin raw material containing a predetermined amount or more of an antibacterial agent. For example, the resin material is first prepared, and then the original resin raw material and the resin raw material containing no antibacterial agent are mixed by adjusting the mixing ratio so that the amount of the antibacterial agent added becomes a predetermined amount.

The amount of the dispersant added in (C) CD) is about 10% of the antibacterial agent by weight, and in (E) above, the amount of the antibacterial agent added to the original resin raw material is about 10% by weight of the antibacterial agent in the original resin raw material. 20
% or more.

When using (C)CD), the antibacterial agent can be evenly dispersed in the molded resin, and when using (E), the antibacterial agent and the resin can be dispersed by increasing the amount of the antibacterial agent added. In order to improve the blendability of the resin, it can be evenly dispersed in the molding resin.

Examples of the means for molding the fluidized resin include injection molding, extrusion molding, press molding, hand lay-up molding, centrifugal molding, and FW molding.

In the above-mentioned molding resin, the antibacterial agent is generally covered with the resin in a fluid state, and the fluid resin flows into the part that comes into contact with the mold surface.
As shown in the figure, the surface layer portion (IA) of the molded resin (1)
contains no antibacterial agent (2) or has a low content of antibacterial agent (2), and a portion containing a sufficient amount of antibacterial abrasive (2) is formed under the surface layer (IA). The thickness of the surface layer (l^) varies depending on the melting point and viscosity of the resin, the difference in specific gravity between the antibacterial agent and the resin, etc., but it is generally It is several microns.

Therefore, when the surface layer portion (IA) is formed of molded resin, there is very little or no antibacterial agent (2) exposed on the surface (1a) of the molded resin, so that sufficient antibacterial property (antibacterial ability) is obtained. ). As shown in FIG.
The antibacterial agent under the surface layer (IA) is removed by scraping off the IA).
2) is to be exposed on the surface. Specific methods for this generally include blasting, cutting, and polishing, but it is a process in which scratches are simply created by rubbing the surface with a wire brush or the like without using special equipment. Also good.

Next, we will show examples of experiments conducted by the present inventors to confirm the usefulness of the method of the present invention.

Experimental Example 1 As an antibacterial agent, zeolite powder bound with silver ions (particle size of about 3 μm) was prepared, and as resin raw materials, three of polyethylene resin, polypropylene resin, and polyvinyl chloride resin were prepared.
I prepared one. Then, resin beads containing 4% and 6% antibacterial agents were made by injection molding from each of the three resin raw materials, each of these resin beads was divided into two, and one surface was subjected to deletion processing by bead blasting. A test piece with deletion processing and a test piece without deletion processing were prepared. Among the resin beads, those using polyethylene resin and polypropylene resin as resin raw materials are as described above (
Those produced by method E) and using polyvinyl chloride resin as the resin raw material were produced by the method (C) described above. In addition,
In method (E), the amount of antibacterial agent added to the original resin raw material is 20%.
%, and in method (C), an antibacterial agent mixed with 10% of a dispersant was added and mixed to polyvinyl chloride resin and melted.

And 10ce Ei of E. coli! A bacterial solution containing 1/ml of bacteria was prepared, and the bacteria WL1mE was dropped onto the surface of each test piece, and after being left at 25°C for 18 hours, an antibacterial confirmation test was conducted to count the number of bacteria. The results are shown in Table 1.

As is clear from Table 1, for all resins, the number of bacteria can be reduced by one order of magnitude when deletion processing is performed, compared to when no processing is performed, indicating that the method of the present invention can improve antibacterial properties. Table 1 Experimental Example 2 The same antibacterial agent as in the previous example was prepared, and the unsaturated polyester resin was prepared as a resin raw material. A polyester resin liquid was prepared.

Then, as shown in Fig. 3, a glass flaking cloak is placed on the metal plate (3) coated with a mold release agent, and a blended unsaturated polyester resin (4) to which an antibacterial agent has been added is coated to a thickness of about 1 inch. Next, a glass Chosopdo strand cloak was placed on top of it, and an unsaturated polyester resin (5) without antibacterial agents was coated to a thickness of about 10 mm. After curing, the resin layer was removed from the metal plate. Peel it off to make a resin piece,
Each of these resin pieces was divided into two parts, and the surface of the resin layer to which the antibacterial agent was added in one piece was subjected to deletion processing using bead plast, and the test piece with deletion processing and the test piece without deletion processing were separated. Created. In addition,
Three sets of test pieces were made.

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

The results are shown in Table 2.

Table 2 It is.

(a)... Antibacterial agent, (1)... Molding resin, (1a)... Surface.

As is clear from Table 2, it was found that antibacterial properties could be improved.

[Brief explanation of drawings]

Claims (1)

[Claims] A method for producing resin molded products with antibacterial properties on the surface by molding a fluidized resin to which an antibacterial agent has been added. A method for producing antibacterial resin molded products that involves deletion processing.