JPH0977042A - Container made of synthetic resin with antibacterial and anti-mold functions - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container made of a synthetic resin which can be easily manufactured at a low cost, and in addition, can display antibacterial and anti-mold functions when the empty container is stored and even after the storage with water by limiting the position where a resin layer with the antibacterial and anti-mold functions is provided, at an effective position. SOLUTION: For a container made of a synthetic resin with antibacterial and anti-mold functions, a resin layer containing a powder of a soluble glass, which can elute a suitable quantity of silver ion in water, is formed at least on the bottom part of the container and the bottom part of the side wall, by a spray method or by an applying method with brush.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin container having an antibacterial and antifungal function, and in particular, it has an antibacterial and antifungal function as a water storage container in an area where water is inconvenient and as a water supply container in the event of a disaster. The addition of an antibacterial and antifungal function not only prevents secondary damage such as poisoning due to water pollution, but also prevents the growth of bacteria and mold during storage of empty containers before filling these containers with water. The present invention relates to a container made of synthetic resin.

[0002]

2. Description of the Related Art Conventionally, in areas where water is inconvenient, it is necessary to store water in daily life, and a glass fiber reinforced polyester resin tank (hereinafter referred to as FRP) is used as a water storage container.
(Abbreviated as tank) has been used. Further, a polyethylene container with a lid (hereinafter abbreviated as a poly container) has been used as a small water storage container. In particular, plastic containers are often used not only in areas where water is inconvenient, but also as water supply storage containers in the event of an unexpected water interruption or disaster. Both of these FRP tanks and plastic containers have not been rusted by moisture, are relatively lightweight, and have excellent strength.

[0003]

However, in such a conventional synthetic resin container for storing water, the storage period of water is prolonged because the container itself does not have an antibacterial and antifungal function. However, there is a problem that bacteria not only grow in water and mold grows on the inner surface of the container near the water surface, which is not only a sanitary problem but also gives an unclean appearance.

As a means for coping with such a problem, for example, Japanese Patent Application Laid-Open No. 4-22361 discloses a resin contact lens containing a soluble glass powder capable of eluting a proper amount of silver ions in a solution. A container is disclosed.

However, in such a conventional synthetic resin container having an antibacterial and antifungal function, since the entire container is made of a resin containing glass powder capable of eluting silver ions, it is used for contact lenses. There is a problem that it is economically impossible to apply to a plastic container and a large and thick container such as a FRP tank, not to mention a small container such as a container.

The present invention has been made in view of such conventional problems, and by limiting the position of the resin layer having an antibacterial and antifungal function to an effective position, a simple process can be performed at low cost. It is an object of the present invention to provide a synthetic resin container that can be manufactured and that can prevent the growth of bacteria and fungi during storage of an empty container and after storage and storage of water.

[0007]

According to the first aspect of the present invention,
A synthetic resin container having an antibacterial and antifungal function, characterized in that a resin layer containing a soluble glass powder capable of eluting a suitable amount of silver ions in water is provided at least in the lower part of the container, The invention according to claim 2 is characterized in that, in addition to the above-mentioned constitution, the resin layer containing a powder of a soluble glass capable of eluting silver ions is a spray coat layer, and has an antibacterial and antifungal function. According to the invention of claim 3, in addition to the constitution of claim 1, the resin layer containing a soluble glass powder capable of eluting silver ions is an overcoat layer. It is a feature.

The soluble glass capable of eluting silver ions used in the present invention is a glass composition having a controlled dissolution rate with respect to water stored in a synthetic resin container or moisture in the air. Weight% silver ion with excellent bactericidal effect
0.4 to 1.6% (Ag ₂ O conversion) content, and crushed to have a particle size of 5 to 60 μm is preferable. Here, the content of silver ions in the glass is 0.
If it is 4% or less, it is necessary to add a large amount of soluble glass to the synthetic resin in order to impart sufficient antibacterial properties, which not only impairs moldability, strength and other mechanical properties of the synthetic resin, but also It is economically expensive and inconvenient. Further, if the content of silver ions in the glass is 1.6% or more, not only is metallic silver deposited during melting of the soluble glass to damage the furnace, but it is also uneconomical. Furthermore, the particle size is 5 μm
When it is below, the dissolution rate of silver from the resin becomes extremely slow, so it is necessary to add a large amount of soluble glass, and when the particle size is 60 μm or more, clogging occurs when kneading into the synthetic resin. In addition to the possibility of causing process troubles, there is a risk of impairing the smoothness of the surface of the container.

The plastic container is usually molded by blow molding (also called blow molding or blow molding) or injection molding. The latter is used in particular for the production of bucket-shaped containers. As the molding resin, any thermoplastic synthetic resin can be used as long as it is used in a flexible container. However, it is preferable to use a polyolefin resin such as polyethylene or polypropylene in terms of cost and hydrophobicity.

On the other hand, since plastic water tanks and large water tanks installed on the roof of a building are insufficient in strength with plastic alone, unsaturated polyester,
Fiber-strength plastic (F
RP). As the molding method of this FRP tank, many methods such as hand-molding, matched die method, SMC method, spray-up method, filament winding method, and continuous molding can be used according to need.

The amount of the soluble glass added to the synthetic resin varies depending on the particle size, type of synthetic resin and expected antibacterial effect, but generally 0.3 to 10.0% (wt%) is preferable. The result is obtained. When the addition amount is 0.3% or less, sufficient antibacterial property cannot be obtained, while when the addition amount is 10.0% or more, the characteristics of the resin, particularly the moldability may be impaired.

Furthermore, the amount of silver ions eluted from a container made of a synthetic resin containing soluble glass has the greatest effect on the antibacterial and antifungal properties, which is the object of the present invention. It was confirmed that it is preferable to set the elution rate of silver ions from the inner surface of the container to 1 to 500 ng / cm ² / day. If the dissolution rate of silver ions is lower than this range, a sufficient antibacterial effect cannot be obtained. On the contrary, if the dissolution rate of silver ions exceeds this range, more than necessary silver ions are eluted and the sustainability of the effect is reduced.

When water containing chlorine such as tap water is put in a container, the water may be slightly clouded or the inner surface of the plastic bottle may be discolored due to the reaction between silver and chlorine even if the elution rate of silver ions is properly selected. However, the inclusion of 1% or less of the hydrotalcite compound in the resin can further improve the maintenance of the transparency of the plastic bottle,
When used for food such as drinking water, there is no fear of impairing the transparency of water, which is convenient.

Of the meltable glass used in the present invention
As a component, SiO ₂, B₂O_Three, P₂O_FiveTangle shape such as
Oxide or Na₂O , K₂O, CaO, MgO, B
aO, Al₂O_Three, TiO₂Modified ZnO, ZnO, etc.
A substance that is soluble in water when it comes into contact with water.
Silver ions dissolved in the glass composition
Those which elute can be used without particular limitation.

Poly containers are commonly used as screw-on lidded containers. At that time, if a thermoplastic resin sealing material containing a powder of soluble glass capable of eluting silver ions as described above is attached to the surface of the back side of the lid in contact with the mouth of the container, the antibacterial and antifungal effect is further enhanced. Can be demonstrated. In addition, the FRP tank is often provided with a screw-on lid or a cover lid, and the same can be said in that case.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples. Example 1 80 mol% B ₂ O ₃ , 10 mol% SiO ₂ , Na ₂ O
The antibacterial and antifungal glass obtained by adding 1.0% by weight of Ag ₂ O and melting it to a soluble glass raw material composition having a composition of 10 mol% was ground to a particle size of 5 to 20 μm. Next, the powder of the soluble glass was dispersed in an acrylic resin organic solvent solution so as to be 10% by weight. Then, the dispersed organic liquid is sprayed from a low-density polyethylene poly container having an internal volume of 18 liters through a hole for attaching a screw-type lid having a diameter of about 5 cm toward the bottom of the poly container and the lower part of the side wall. Was spray applied. It was left at room temperature of about 30 ° C. to form a dried spray coat layer. Distilled water was placed in this plastic container, and after 30 days, the amount of silver ion eluted was measured. The amount of silver ions eluted in distilled water after 30 days was 5.1 ng / cm ² . As an antibacterial test, distilled water containing 10,000 E. coli / ml was added, and the number of viable cells after 24 hours was measured. After 24 hours, the viable cell count was significantly reduced to 10 cells / ml or less.

Example 2 P ₂ O ₂ 50 mol%, Al ₂ O ₃ 3 mol%, MgO 4
An antibacterial and antifungal glass composed of 0 mol%, Na ₂ O 5 mol% and Ag ₂ O 2 mol% was crushed to a particle size of 10 to 40 μm. Next, 10% by weight of this soluble glass powder was added to a styrene diluted solution of an unsaturated polyester resin and kneaded sufficiently. Then, this unsaturated polyester resin liquid,
Diameter of FRP tank with a capacity of 200 liters is about 60 cm
The bottom of the cylindrical FRP tank and the lower part of the side wall were brush-painted through the hole for the cover lid and left to dry at room temperature of about 30 ° C. to form an overcoat layer having antibacterial and antifungal properties. Tap water was placed in this FRP tank, and the elution amount of silver ions was measured after one week, and a result of 4.1 ng / cm ² was obtained. As an antibacterial and antifungal test, after releasing the tap water after the above-mentioned silver ion elution amount test, a container in which water drops were slightly attached to the inner wall surface of the FRP tank was covered with a lid and left for 2 months. The inside of the FRP tank was rinsed and the number of bacteria was measured. For comparison, the FRP tank that did not have the same antibacterial and antifungal carver coat layer was sprayed with tap water, discarded excess water, and left for 2 months in the same manner with water droplets slightly adhering to the inner wall surface. Then, the number of bacteria was measured. The number of bacteria, mold and yeast in the FRP tank with the carver coat layer was 0, but the untreated one had about 50 bacteria, mold,
The number of yeasts was about 30.

[0018]

According to the first aspect of the present invention, a resin layer having an antibacterial and antifungal function containing a soluble glass powder capable of eluting silver ions is provided on the bottom surface or lower side wall of a synthetic resin container. Since it is installed only in the part, it is possible to manufacture a container that effectively exhibits the antibacterial and antifungal function of the antibacterial and antifungal resin at low cost, and also to propagate bacteria and mold even when storing empty containers and after starting to use water storage. Can be prevented and a clean state can be maintained for a long period of time.

According to the second aspect of the present invention, the resin layer having the antibacterial and antifungal function can be easily formed by using a spray gun, and the poly container having the antibacterial and antifungal function can be used as a conventional poly container. Can be manufactured easily and at low cost.

According to the third aspect of the present invention, the resin layer having an antibacterial and antifungal function can be easily formed by brushing, and a large water tank such as an FRP tank can be formed by the conventional FRP.
The tank can be easily and inexpensively converted into a tank having an antibacterial and antifungal function.

Claims (3)

[Claims] 1. A synthetic resin having an antibacterial and antifungal function, characterized in that a resin layer containing a soluble glass powder capable of eluting a proper amount of silver ions in water is provided at least in a lower portion of a container. Container. 2. The synthetic resin container having an antibacterial and antifungal function according to claim 1, wherein the resin layer containing a powder of soluble glass capable of eluting silver ions is a spray coat layer. 3. The synthetic resin container having an antibacterial and antifungal function according to claim 1, wherein the resin layer containing a powder of soluble glass capable of eluting silver ions is an overcoat layer.