JPH06220391A - Fluororesin-based coating compound - Google Patents

Abstract

PURPOSE:To obtain a hygienic fluororesin-based coating compound providing high safety, durable antimicrobial action and mildew resistance without damaging characteristics such as non-tackiness, heat resistance and wear resistance in coating of a fluororesin-based coating compound. CONSTITUTION:This fluororesin-based coating compound comprises a heat- resistant antimicrobial agent and a fluororesin. A silver-based inorganic antimicrobial agent or a copper-based inorganic antimicrobial agent is used as the heat-resistant antimicrobial agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin-based paint, and more particularly to a fluororesin-based paint having antibacterial properties and non-adhesive properties, which can be applied to metal, ceramics and general solid surfaces.

[0002]

2. Description of the Related Art Fluororesin coatings are non-sticky, heat resistant,
It is used in various industrial fields due to its abrasion resistance, chemical resistance, electrical insulation, etc., such as electric rice cookers, various pots, rice cake makers, hot plates, pans, jar pots, knives, and irons. It is used for household products such as, for example, dies for rubber and plastics, jigs for painting and plating, and industrial products such as fixing rollers for copying machines.

[0003]

However, when the above fluororesin coating material is coated, the characteristics such as non-adhesiveness, heat resistance and abrasion resistance can be utilized, but on the other hand, it is necessary to impart further antibacterial property to the surface. Was difficult. That is, when the fluororesin coating material is coated, since heat treatment is performed for finishing, conventional organic antibacterial agents such as antibiotics have problems such as poor heat resistance and decomposition and no effect. It was In particular, when a fluororesin coating film is formed on a food heating device for processing or storing food materials by indirect heating or heating from the outside, or a wall material in a high humidity environment. It was strongly desired to provide antibacterial and antifungal properties with high safety and durability.

Further, in the case of food utensils, a jar pot, a heat-retaining rice cooker, or the like whose taste and aroma do not change even if the food is stored for a long time, a container for thawing frozen food and directly contacting living things Those that can prevent the reproduction of fungi such as
That is, there has been a demand for a surface-treated product that is hygienic, highly safe, and has a long-lasting antibacterial effect.

[0005]

The fluororesin-based paint according to claim 1 of the present invention is characterized by containing a heat-resistant antibacterial agent and a fluororesin.

The fluororesin-based paint according to claim 2 of the present invention is the fluororesin-based paint according to claim 1, wherein a silver-based inorganic antibacterial agent or a copper-based inorganic antibacterial agent is used as the heat-resistant antibacterial agent. Is characterized by.

The present invention uses a fluororesin containing a heat-resistant antibacterial agent to prepare a fluororesin-based paint, and when a coating film is formed from this fluororesin-based paint, the antibacterial properties are excellent in safety and durability. Is used as a grant.

Furthermore, if a fluororesin-based coating material containing a heat-resistant antibacterial agent and a fluororesin is applied to the inner surface of the cooking utensil, the persistent antibacterial effect can prevent the deterioration of food due to the growth of microorganisms, and can be performed for a long time. Even if the food is stored, it is possible to prevent the taste and smell of the food from changing.

The fluororesin usable in the present invention includes:
Polyvinyl fluoride (PVF), polyvinylidene fluoride (PVdF), polychlorotrifluoroethylene (PCTF)
E), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer copolymer Polymer (ECTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), etc. are available, but PTF is non-adhesive.
E, ETFE, FEP, PFA and the like are preferable, and they may be used alone or in a composite composition in which they are mixed. Also,
Fluorine resin, acrylic resin, silicone rubber, fluororubber, epoxy resin, polyimide resin, polyamideimide resin, urethane resin, polyphenylene sulfide resin, polyparabanic acid amide resin, polyetherimide resin , A resin other than a fluororesin such as polyether sulphide resin and para-hydroxybenzoic acid resin may be mixed as a binder, or an appropriate amount of elastomer may be mixed. These components of the present invention can be used in the form of a liquid coating material by being dispersed in a powder form or an aqueous dispersion medium or an organic solvent dispersion medium.

As the heat-resistant antibacterial agent, a known antibacterial, bactericidal and mildew-proof substance (a substance having a bacteriostatic action) having heat resistance, that is, a fluororesin coating film is formed. Any one can be used as long as the effect is not impaired by the temperature and the antibacterial effect is not significantly decreased with time. Examples thereof include metals such as silver, copper, zinc, and tin, and organic or inorganic compounds containing the same. In consideration of safety and sustainability of effects, silver-based inorganic antibacterial agents, copper-based Inorganic antibacterial agents are preferred.

As the silver-based inorganic antibacterial agent, for example, fine particles in which silver is supported on ceramics are preferable in terms of durability and discoloration resistance. Commercially available products are those manufactured by Toagosei Kagaku Co., Ltd. Novalon (trade name) is mentioned. Examples of ceramics that can be used in the silver-based inorganic antibacterial agent include porous fine powders containing alumina, calcined white porcelain, titanium oxide, silica, ferrous oxide, etc. as main components and having an average particle size of 5 μm or less, preferably 1 μm or less. .

The heat-resistant antibacterial agent may be contained in any amount as long as the effect of the heat-resistant antibacterial agent is exhibited.
It is preferable to use a dispersion of 50% by weight as a fluororesin-based coating material, and more preferably 3 to 30% by weight. If it is less than 1% by weight, the antibacterial property is insufficient,
If it is added in an amount of 50% by weight or more, the coating film strength of the fluororesin-based coating composition is lowered, which is not preferable.

Any of a stirring mixing method, a tumbler mixing method, a shaking mixing method, a ball mill mixing method and a roller mill mixing method may be used for mixing the heat resistant antibacterial agent and the fluororesin.

The solvent, dispersant and binder component used are finally determined from the dispersibility, coatability and film forming ability. From the viewpoint of the antibacterial effect per addition amount of the heat-resistant antibacterial agent, it is preferable that the heat-resistant antibacterial agent is unevenly distributed on the surface of the fluororesin coating material. Therefore, the object to be coated is coated with the fluororesin mixed with the binder in advance. In the two-layer coating on which the fluororesin layer is further formed, it is preferable to disperse and mix the heat-resistant antibacterial agent with the fluororesin on the surface from the viewpoints described above and from the viewpoint of coating strength.

It is sufficient that the object to be coated does not deteriorate near the baking temperature, and if it is a solid such as various metals, glass, ceramics including ceramics, and heat resistant plastic, it can be coated regardless of its shape and size. . The surface of the article to be coated must be thoroughly washed before painting. Wash with solvent,
Dipping with acid, alkali, detergent, shower, bubbling, ultrasonic cleaning, and other general cleaning methods are used.

Thereafter, the following treatment may be carried out in order to further improve the adhesion between the coating film and the article to be coated. That is, sand blast, shot blast, grit blast, honing, paper scratch, hairline treatment, thermal spraying of metal or ceramics, alumite treatment, boehmite treatment, cracking treatment, chemical etching, and chemical conversion coating treatment are added.

The following two main coating methods are used. When heat resistant antibacterial agent and fluororesin are dissolved or dispersed, brush coating, dipping, air spraying, electrostatic spraying, spatula coating, roller coating, curtain coating, spin coating using centrifugal force, electric permanent coating In the case of mixing the respective powders of the heat-resistant antibacterial agent and the fluororesin, the coating method is powder spraying, electrostatic spraying, fluidized dipping, electrostatic fluidized dipping, probe backing, and pressure molding.

After coating as described above, if dried, the heat resistant antibacterial agent and the solid content of the fluororesin remain and a coating film is formed. If the coating is repeated at this stage, the required film thickness can be obtained. The drying temperature is determined by the type of solvent, but in the case of powder coating, baking treatment can be performed immediately after coating. The baking temperature is near the melting point of the fluororesin used.
Then, after the baking treatment, it is allowed to cool and used as it is, or it is subjected to polishing, cutting, and pressing treatments so that the dimensional accuracy and the surface roughness become predetermined.

The coating film thus formed contains a heat-resistant antibacterial agent, but it cannot reduce the inherent non-adhesiveness of the fluororesin. In addition, the fluororesin-based coating material containing the heat-resistant antibacterial agent can be directly applied to form a coating film, or the fluororesin-based coating material can be formed into a film and attached to form a fluororesin coating film. And
The same effect as the coating film formation can be obtained.

Regarding the heat-resistant antibacterial agent, the particle size and specific gravity of the particles are similar to those of the fluororesin paint (specific gravity of silver-based inorganic antibacterial agent particles supported on ceramics is 2.5 to 3.0,
The specific gravity of the fluororesin particles is 2.1 to 2.2, the average particle size of the silver-based inorganic antibacterial agent particles is 5 μm or less, the particle size of the fluororesin particles, the liquid paint is 0.2 to 0.4 μm, and the powdery paint is 5 to 5. 35μ
m), they both form a uniform distribution during the initial film formation before baking, and the fluororesin component has the property of migrating to the upper layer of the film during baking. This is because it is considered that the extreme surface layer of the final formed film is covered with the fluororesin due to the fact that the specific gravity is slightly lighter than that of the inorganic antibacterial agent and it has thermal fluidity.

The fluororesin-based coating material of the present invention is non-adhesive,
Any of those which are required to have heat resistance, abrasion resistance, chemical resistance, electric insulation, and antibacterial properties can be suitably used.

The above-mentioned fluororesin paint containing the heat-resistant antibacterial agent and fluororesin is used for the inside of electric rice cookers, electric pots, pans, rice cake cookers, hot plates, pots, pans, ovens, roasters, etc. Or food heating equipment such as tempura used for them, jar pots, food storage equipment containers such as heat-retaining lunch boxes, frozen food thaw plates,
Kitchen knives, storage containers such as closed containers for food, cooking utensils, various food utensils, kitchen utensils such as triangular corners and drainers, toiletries such as cups and toothbrushes, bath products such as washbasins, bathtubs and soap dishes, It can be applied to sanitary equipment such as water faucet, hand sanitizer, drip board, etc., medical supplies, refrigerators, home appliances such as dishwashers.

In the case of food appliances, a fluororesin paint containing a persistent antibacterial agent and a fluororesin may be applied to at least the surface in contact with food.
From the viewpoint of durability and safety, a silver-based inorganic antibacterial agent is preferable.

The food appliance of the present invention is particularly suitable for food preservation and cooking equipment in which bacteria such as organisms easily propagate, and jar pots, electric pots, heat-retaining electric rice cookers, etc. for keeping food for a long time. The effect is remarkable when used.

[0025]

【Example】

Example 1 Hereinafter, the antibacterial effect of the fluororesin coating material of the present invention will be described with reference to examples.

The surface of an aluminum plate having a size of 4 cm × 4 cm was degreased with trichlene and activated by sandblasting with alumina particles, and the resin content of a commercially available one-coat PTFE coating (product name 420-108 manufactured by DuPont) was
5 Wt% of silver-supported ceramic fine powder (average particle size: 0.5 μm, Toa Gosei Chemical Co., Ltd., trade name Novalon)
Is coated and mixed on the surface of a commercially available primer, dried at 100 ° C. for 10 minutes, baked at 380 ° C. for 15 minutes, and allowed to cool in the air to obtain a metal plate of the present invention 1, which is PTFE.
Replace the paint with a commercially available two-layer coated product and use PTFE for the undercoat layer.
Paint mixed with adhesive (Product name: EK manufactured by Daikin Co., Ltd.
1908GY), using a surface PTFE coating (trade name EK-4612WS manufactured by Daikin Co., Ltd.) for the resin component,
A metal plate prepared in the same manner as the product 1 of the present invention was used as the product 2 of the present invention except that a ceramics fine powder supporting 5 Wt% of silver (trade name Novalon manufactured by Toagosei Co., Ltd.) was added and mixed. Comparative products 1 and 2 were prepared as metal plates coated with a coating film in which the ceramic fine powder supported by the same method as above was not mixed. After inoculating these surfaces with an Escherichia coli solution, the surfaces were wrapped and the viable cell count after storage at 27 ° C. for 3 hours was measured. The same operation was performed without using the sample as a control. The results are shown in Table 1.

[0027]

[Table 1]

As is clear from Table 1, the metal plate coated with the fluororesin-based coating material of the present invention showed an excellent antibacterial effect even though it was treated at a high temperature during the fluororesin processing.

Example 2 (1) Electric Rice Cooker A container of an electric rice cooker made of aluminum having an inner diameter of about 20 cm and a depth of about 12 cm was degreased with trichlene and activated by sand blasting with alumina particles to be commercially available. PT
To the resin component of the FE coating, 30 Wt% silver fine powder supporting ceramics (average particle size 0.5 μm, Toa Gosei Kagaku Co., Ltd., trade name Novalon) was added and mixed, and the coating was applied on the commercially available primer surface. After drying at 10 ° C for 10 minutes and baking at 380 ° C for 15 minutes, the container was left to cool in the atmosphere to prepare a test container, and the same method as the test container was used. The prepared product was prepared as a comparative container. Both of them were mixed with commercially available standard rice in the same process and cooked in the same process (washed rice → flooded 1 hour → cooked rice), then kept at 40 ° C. for 12 hours and compared, and cooked in a container according to this example, The cooked rice was fluffy, sweet and sticky, and had almost the same taste and appearance as freshly cooked, but the rice preserved in the comparative container was obviously inferior in flavor to freshly cooked rice.

(2) Jarpot A fluororesin-based film containing a silver-based inorganic antibacterial agent is formed on the inner surface of an aluminum die cast or ceramics container used as the inner layer of the jar pot, like the electric rice cooker. Was prepared as a test pot, and similarly to the test pot, a test pot coated with a coating film to which no silver-based inorganic antibacterial agent was added and mixed was prepared as a comparative pot. 9 tap water for both
After warm water heated to 0 ° C. was put therein, the bottle was stoppered and allowed to stand for 6 hours, the taste of the warm water was compared. As a result, the warm water of the comparative pot clearly showed a change in taste as compared with the warm water of the test pot.

As is apparent from Example 2, the apparatus surface-treated with the fluororesin coating material of the present invention has excellent performance with no change in taste and aroma due to alteration even if food or water is stored for a long time. Indicated.

Although an electric rice cooker and a jar pot have been described above, an electric pot, a baking mold for cakes and cuties, an oven top plate, and a hot plate (hot plate).
The present invention can be applied in various modes that require antibacterial properties, such as cooking tools for heat treatment, food containers including kitchen utensils, and other cooking utensils.

Further, it is also possible to form a fluororesin film by forming a film of a fluororesin paint containing a heat-resistant antibacterial agent and attaching it.

[0034]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it is hygienic and highly safe without impairing the properties such as non-adhesiveness, heat resistance, and abrasion resistance when a fluororesin coating material is coated. As a result, a fluororesin-based coating which gives a long-lasting antibacterial and antifungal property was obtained. Furthermore, when the food was stored for a long time in a container coated with the fluororesin-based coating material of the present invention, it showed an excellent effect that the taste and aroma did not change due to alteration.

Claims (2)

[Claims] 1. A fluororesin-based coating material containing a heat-resistant antibacterial agent and a fluororesin. 2. The fluororesin-based paint according to claim 1, wherein the heat-resistant antibacterial agent is a silver-based inorganic antibacterial agent or a copper-based inorganic antibacterial agent.