JPH0675874B2 - Method for producing resin member having antibacterial property - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing a resin member having an antibacterial property, more specifically, a resin member carrying an antibacterial agent on the surface of the member.

(Prior Art) As a conventional method for supporting an antibacterial agent on a resin member, there is, for example, the following method.

Polyurethane, SBR, NBR, other synthetic rubber, polyacrylic acid ester, solvent system of binder resin such as nylon, water-based solutions or dispersions mixed with various antibacterial agents, the resulting treatment agent into a sheet A method of applying and solidifying and drying the resin liquid (for example, JP-A-55-165927), emulsifying the antibacterial agent with a surfactant to 2 to 30% by weight, and dipping,
A method in which the surface of a component is applied by spraying or brush coating and then dried (JP-A-59-124428), and when the component is made of a resin material such as polypropylene, polyester, polystyrene, etc. There is a method of mixing and kneading about 0.1 to 10% by weight at the time of manufacturing the raw material pellet (JP-A-59-124428).

(Problems to be Solved by the Invention) However, in such a conventional method, the types of the binder resin and the resin for forming the member are selected depending on the application, but they are stable in the state of being a product. Therefore, the antibacterial agent encapsulated in the resin does not easily exude to the surface, and therefore only the antibacterial agent that appears on the surface of the resin is effective, so the utilization rate is low, and it appears on the surface. Since such a substance easily disappears, the antibacterial effect has a relatively short lasting effect, and the method of simply applying an antibacterial agent has a problem in that the antibacterial effect quickly disappears due to dropping or the like and the antibacterial effect is also insufficient.

(Means for Solving Problems) In order to solve the above-mentioned conventional problems, the present invention provides a foamed polyurethane or the like having high antibacterial agent utilization rate and excellent antibacterial effect durability. To provide a method for producing a resin member, in the present invention, in producing a resin molded article having antibacterial properties by foaming a foamable material such as a urethane foam material in a casting mold, The method is characterized in that, before pouring the foamable material into a mold, a liquid in which an antibacterial agent is dispersed or dissolved is applied to the inner surface of the mold and then the foamable material is poured.

The method of the present invention will be described below with reference to the case where a urethane foam material is used as the foamable material.

A resin member having an antibacterial property made of urethane foam (hereinafter referred to as foam) obtained by the method of the present invention is particularly useful as a member constituting a ventilation path of an automobile air conditioner.

The antibacterial agent used in the present invention may be a commonly used one, but it is also one embodiment of the present invention to use an antibacterial agent having reactivity with an incyanate group, and as an example of such an antibacterial agent Include those mainly containing thiobendazole or parachlorometaxylenol.

The foam material used in the present invention is a general material, and is usually composed of a polyol, a tertiary amine, water and an isocyanate.

Polyethylene glycol (PE
G), polypropylene glycol (PPG) and the like and mixtures thereof.

Examples of the isocyanate include methylene diisocyanate (MDI) and tolylene diisocyanate (TDT).

The tertiary amine includes tolylenediamine, triethylamine and the like, and a mixture thereof can also be used.

When an antibacterial agent having reactivity with an isocyanate group is used as described above, the foam material has a molar ratio of the isocyanate group to the hydroxyl group of the polyol (hereinafter referred to as an isocyanate index) of more than 100%, It is preferably 105 or more.

Foam materials are generally prepared by weighing polyols and isocyanates in almost equimolar amounts and putting them in separate containers.
The amine and water are added to the container containing the polyol, and the liquid in which the antibacterial agent is dispersed or dissolved is applied to the inner surface of the mold, that is, the surface in contact with the injected foam material, and foaming of the foam material begins. Pour into the mold quickly before foaming and then remove from the mold.

(Operation) Next, the operation will be described.

In the method of the present invention, the antibacterial agent is applied to the inner surface of the mold and then the foam material is poured therein to foam,
The urethane and the antibacterial agent have a physical adsorption force, and thus are harder to disappear than those simply coated, and the antibacterial agent itself has a significantly improved utilization rate because of the antibacterial agent on the surface.

The physical adsorption force in this case is that the antibacterial agent comes into contact during the resin formation process on the surface, so that the creamy urethane in the initial stage of the reaction cures with the antibacterial agent entrapped as shown in Fig. 1. Is what you get.

Therefore, since the antibacterial agent is present on the surface and the antibacterial agent enters into the base material like a wedge, it is hard to disappear and an antibacterial treated resin member having a high effect persistence can be obtained.

When the antibacterial agent to be used next reacts with the isocyanate group, the antibacterial agent applied to the mold surface reacts with the isocyanate group remaining after the reaction, and the antibacterial agent is fixed on the surface of the mold urethane, which has an antifungal effect. Efficiently. This reaction will be described below by taking parachlorometaxylenol as an antibacterial agent as an example.

Furthermore, in this case, the antibacterial agent is applied to the mold, and the foam material liquid is poured into the mold to cause foaming. Therefore, in addition to fixing by the chemical reaction as described above, the antibacterial agent and the antibacterial agent are used as described above. The agent has a physical adsorption force, and the antibacterial agent is physically strongly adsorbed on the foam surface layer and is less likely to disappear, so that the antibacterial effect lasts longer.

(Examples and Comparative Examples) Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 1 As a polyol Triether polyol FA-703 (manufactured by Sanyo Kasei), as isocyanate Methylene diisocyanate MR-200 (manufactured by Nippon Polyurethane) and C1 triethylamine as an amine were used.

In the first container, 10 g, 0.05g and 0.2g of water, and put it in the second container. Weighed 4.0g.

Also, as an antibacterial agent, 0.1 g of thiobendazole (TBZ) was dispersed in 10 g of ethanol, and 1 g of this dispersion was used in a mold (l ₁ = 20 cm, l ₂ = 60 cm, l ₃ = 20 cm, shown in FIG. 2). T = 3cm)
And then the above foam materials are mixed and forcibly stirred and then poured into a mold [mold-1]
Got

Comparative Example 1 The foam material shown in Example 1 was molded without applying the antibacterial agent dispersion liquid to the mold, and after demolding, the antibacterial agent dispersion liquid of Example 1 was the same as [Ex-1]. Coated on the surface of the foam to obtain a mold foam [ratio -1].

Example 2 In Example 1 Except that the amount was changed to 4.5 g.
2] was obtained.

Comparative Example 2 Molded foam [Comparative-2] was prepared in the same manner as Comparative Example 1 except that the foam material was the same as that used in Example 2.
Got

Next, for the mold foams [Execution-1], [Execution-2], [Ratio-1] and [Ratio-2] obtained in Examples 1-2 and Comparative Examples 1-2, the antibacterial agent was maintained as follows. The sex was evaluated. Each foam is cut at intervals of 3 cm, and the foam 4 is attached to the connecting portion of the duct 3 of the evaporator of the air conditioner as shown in FIG. In the figure, 5 indicates a cleaning unit. The foam was removed every three months, the adhering antibacterial agent was washed off with ethanol, and the amount was measured by liquid chromatography. Fig. 4 shows [Actual-2].
The foam of [Ratio-2] is shown in FIG.
For comparison, FIG. 5 also shows the results measured for the foam [Ex-1].

From Fig. 4, in case of applying antibacterial agent in-mold at the time of molding [Execution-1], 0.1 mg or more is adhered even after 12 months have passed, but in case of just applying [Ratio-1], it is 0.1 mg in 9 months. It is below.

In addition, from Fig. 5 [Actual-1], 0.1 mg was maintained until 18 months, and in [Actual-2], 0.1 mg or more was adhered even after 2 years, but in [Comparison-2], it was 0.1 mg in 9 months. below mg.

Further, regarding the effect of the antibacterial agent, each foam was subjected to the following MIL standard medium, inoculated with black mojito (Aspergillus) floating in the air, and its growth state was examined. The obtained results are shown in Fig. 6 for [Ex-1] and [Ratio-1].
[Actual-2] and [Ratio-2] are shown in FIG. The 7th
For comparison, the figure also shows the measurement results for the foam [Ex-1].

(MIL _{Medium) KH 2 PO 4: 0.7g,} NH 4 NO 3: 1.0g, ZnSO 4 · 7H 2 O: 0.002g, K 2 HP
O ₄ : 0.7g, NaCl: 0.005g, MnSO ₄・ 7H ₂ O: 0.001g, MgSO ₄・ 7H
_{2 O: 0.7g, FeSO 4 ·} 7H 2 O: 0.002g, H 2 O: 1000ml, dextrose: 1.
0%, Evaluation point in the figure Good (1)> Medium (2)> Very small (3)> Very small (4)
> No growth (5), as shown in Figures 6 and 7, the effect gradually decreases when the amount of antibacterial agent adhered falls below 0.1 mg, but 0.1 mg
From the above, it can be seen that the effect continues.

(Effects of the Invention) As described above, in the present invention, when a resin member having an antibacterial property is manufactured by the mold foam method, an antibacterial agent is applied to the inner surface of the mold before pouring the foam material into the mold. Since the foam material is then injected, the surface of the foam is hardened by entraining the antibacterial agent, and the antibacterial agent does not easily disappear and the antibacterial property continues for a long time. When the one that reacts with the isocyanate group is used, the isocyanate group remaining after the reaction and the antibacterial agent react and are fixed, and the rust-proof effect is more effective, the utilization rate is high, and the durability is large.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a state in which an antibacterial agent is physically attached to a foam produced by the method of the present invention, FIG. 2 is a perspective view of a mold used in Examples and Comparative Examples, and FIG. 3 is a foam. The antibacterial agents of the foams of Examples 1 and 2 and Comparative Examples 1 and 2 are sectional views of the connecting portion of the duct of the air conditioner evaporator to which the foam is attached to evaluate the durability of the antibacterial agent of Examples 1 and 2 and Comparative Examples 1 and 2. Graphs showing changes with time in the amount of adhesion, FIGS. 6 and 7 are graphs showing changes with time in microbial growth of the foams of Examples 1-2 and Comparative Examples 1-2. 1,4 ... urethane foam 2 ... antibacterial agent, 3 ... duct 5 ... cooling unit

Claims (1)

[Claims] 1. When a foamable material is poured into a mold and foamed in the mold to produce a resin member having antibacterial properties, the foamable material is applied to the inner surface of the mold before being injected into the mold. A method for producing a resin member having antibacterial properties, which comprises applying an antibacterial agent and then pouring the foamable material.