JPH0826805A - Manufacture of artificial marble article having antimicrobial activity - Google Patents

Abstract

PURPOSE:To obtain effective antibacterial activity having a long durability with a small amount of a bactericidal agent and to produce an artificial-marble article having excellent appearance and bactericidal activity, by forming a heat-hardening resin coating containing the bactericidal agent on the surface of an injection mold in advance and subjecting a resin composition to injection molding. CONSTITUTION:A heat-hardening resin coating, which contains 0.05-10wt.% of silver zeolite powder having an average particle diameter of <=40mum as the bactericidal agent, is formed on the surface of an injection mold. Subsequently, a resin composition containing mainly a heat-hardening resin and a filler is injected into the injection mold and cured. By this process, the heat-hardening resin coating having antibacterial activity is adhered and transferred to the molding surface of the resin composition. A part or the total of ion-exchangeable sites of the zeolite used as bactericidal agent are preferably replaced with silver ions and ammonium ions. Through this process, an article having excellent antibacterial activity and free from discoloration is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an artificial marble product having an antibacterial property, which is used for a sink, a washbasin, a toilet article, a household appliance such as a bathtub, a tabletop and the like.

[0002]

2. Description of the Related Art Artificial marble products have excellent characteristics such as heat resistance, hardness, abrasion resistance, water resistance and stain resistance, and are excellent in appearance and design.
It is often used for table tops, etc., but in these applications it is often used under conditions suitable for the growth of mold and bacteria due to warm and humid conditions, adhesion of nutrients, contamination, etc. In-hospital infection due to Staphylococcus (MRSA) has become a problem, and it has been desired to impart antibacterial properties to hospitals and equipment for public use, which are frequently used by an unspecified number of people.

However, general artificial marble products are
Compared to wood-based materials made from natural products, the material itself is less prone to bacterial and mold growth, but depending on the environment and conditions in which it is used, it can be prevented from being soaked or propagated by these microorganisms. There wasn't.

As a method for solving these problems,
A method in which an antibacterial agent is added to a resin composition composed of a thermosetting resin and a filler, and the mixture is dispersed and poured into a casting mold to be cured.

A method of injecting a thermosetting resin composition into a casting mold in advance and curing it, and then applying an antibacterial coating material containing an antibacterial agent on the surface of the molded product.

As described in JP-A-5-058698, a microencapsulated filler containing an antibacterial agent in mother particles to be antibacterial fillers or child particles attached to the mother particles is prepared by thermosetting a matrix. There has been a method of forming an artificial marble raw material by dispersing it in a resin and molding this.

[0007]

[Problems to be Solved by the Invention] An antibacterial agent is added to a resin composition comprising a thermosetting resin and a filler, which is a conventional production method,
In the method of obtaining an artificial marble product in which the mixed and dispersed material is poured into a casting mold and hardened, only a part of the added antibacterial agent appears on the surface, and most of it is dispersed inside the cast material. Therefore, it does not act effectively on bacteria and mold attached to the surface, and it is necessary to add a large amount of antibacterial agent to exert a sufficient antibacterial effect, which is not economically advantageous.

In the method of injecting the thermosetting resin composition into the casting mold in advance and curing it, and then applying the antibacterial coating material containing the antibacterial agent to the surface of the molded product, a small amount of the antibacterial agent is used. Although it is possible to obtain effective antibacterial properties, sufficient adhesion of the coating film cannot be obtained unless the surface of the molded product is polished.
The number of steps is increased and labor is required, and in particular, in the case of a product having a complicated shape, it is necessary to work for uniform application.
It had a defect that coating unevenness was likely to occur.

Even in the method of dispersing and molding a microencapsulated filler containing an antibacterial agent in a thermosetting matrix resin, a step of forming a capsule is required, and it takes a lot of man-hours and the antibacterial agent is partially used. It worked only effectively and was inefficient.

Further, as an antibacterial treatment method for resin molded products,
Before filling the molten synthetic resin into the cavity in the mold,
An antibacterial treatment method for a resin molded product, characterized in that a mold release agent containing an antibacterial agent is applied to the inner surface of the cavity in advance, and the above antibacterial agent is transferred onto the surface of the molded product at the time of mold release ( Japanese Patent Laid-Open No. 63-130312), but in the case of producing an artificial marble product, even if a thermosetting resin composition is cast after mixing and applying a release agent applied to a casting mold. However, the antibacterial agent dispersed in the release agent cannot be completely transferred to the surface of the molded article, does not adhere strongly, and it is difficult to impart durable and stable antibacterial property.

In the method of adding an organic antibacterial agent, many of the antibacterial agents are harmful to the human body, and generally they are unstable to heat, so that they may be deteriorated in the molding process or their effects may be deteriorated. Also, when used for a long time, it is easily affected by ultraviolet rays.

According to the present invention, after forming a thermosetting coating film containing silver zeolite powder on the mold surface of a casting mold, the thermosetting resin composition is cast to obtain the antibacterial coating film and the antibacterial coating film. By integrating with a thermosetting resin composition to form an antibacterial surface, an efficient and durable antibacterial effect can be obtained by using a small amount of antibacterial agent, and an antibacterial agent with good appearance can be obtained. The purpose is to obtain natural marble products.

[0013]

The present invention provides a thermosetting resin coating film containing 0.05 to 10% by weight of a silver zeolite powder having an average particle diameter of 40 μm or less as an antibacterial agent on the surface of a casting mold. After being formed, a thermosetting resin and a resin composition containing a filler as a main component are injected into the casting mold to be cured, whereby the thermosetting resin coating having antibacterial properties is formed into the resin composition. It is a method for producing an antibacterial artificial marble product, which is characterized in that it adheres to or transfers to an object molding surface.
By substituting a part or all of the ion-exchangeable ions in zeolite with silver ions and ammonium ions, it is intended to obtain an artificial marble product which has an excellent antibacterial effect and has no discoloration.

Further, by adding the metal oxide in an amount of 0.05 to 20% by weight to the thermosetting resin coating film applied to the mold surface, silver ions are generated due to the effect of the coexisting metal oxide. Less elution and improved discoloration.

The silver zeolite powder used in the present invention has silver ions and ammonium ions ion-bonded to the zeolite to stabilize the silver ions inside the three-dimensional framework structure of the zeolite. Further, the antibacterial property is imparted without losing the characteristics. By combining ammonium ions,
It is possible to prevent discoloration of silver zeolite (actual fairness 6
-068844). A good antibacterial property is obtained when the content of silver ions relative to zeolite is 0.1 to 15% by weight. Further, ammonium ion is 0.5 to 0.5 with respect to silver zeolite.
It is desirable that the content is in the range of 3.0% by weight.

In the present invention, silver ion powder is added as an antibacterial agent in an amount of 0.05 to 20% by weight with respect to the thermosetting resin coating film coated on the mold surface to obtain silver ion. The elution is prevented and the safety against discoloration is significantly improved. Examples of the metal oxide used in the present invention include zinc oxide, alumina, titanium oxide,
Iron oxide, magnesium oxide, calcium oxide and the like can be added by a method of coating the surface of silver zeolite powder, or a method of simply mixing and dispersing particles in a resin liquid.

The amount of silver zeolite added to the thermosetting resin is 0.05 to 10% by weight based on the nonvolatile content of the resin liquid.
Within the above range, the antibacterial effect can be obtained without causing any problems in the manufacturing process of the artificial marble product and the color and appearance of the product. If the addition amount is 0.05% by weight or less, sufficient antibacterial properties are not exhibited, and if it is 10% by weight or more, the transparency is lowered, the antibacterial agent is precipitated in the resin liquid, and the viscosity is increased. Neither is it preferable.

In the antibacterial agent used in the present invention, silver ions are ionically bonded to zeolite, but the general properties of the zeolite itself are retained without being lost, and an antibacterial effect is added. is there. Silver zeolite is P
Has acid resistance and alkali resistance in the range of H3 to PH13,
Since it withstands temperatures up to 550 ° C., it can be used without any problem at the operating temperature for applications requiring heat resistance, and the performance is not deteriorated.

Further, in the present invention, since silver ions are used as the antibacterial metal ions, the antibacterial effect is greater than that of other antibacterial metals, and the ions eluted in trace amounts during use are not toxic and safe for the human body. is there. Further, the silver zeolite is a white powder and has an average particle diameter of 40 μm or less, preferably 0.6 to
By using a fine powder of 10 μm, it does not precipitate in the resin liquid in a short time, has a small influence on the color tone, and does not show a change in the color tone which is an obstacle to the appearance with respect to the addition amount within the above range. .

As a method for forming an antibacterial coating film on a casting mold, a thermosetting resin having an affinity for the thermosetting resin composition to be cast and capable of constituting the surface of the molded product. There is a method in which a liquid material in which an antibacterial powder is dispersed in a polymerizable monomer or a mixture thereof is applied to the mold surface, and a liquid diluted with a solvent can be used if necessary.

As the thermosetting resin constituting the antibacterial coating film, unsaturated polyester, epoxy (meth) acrylate prepolymer, melamine (meth) acrylate prepolymer, methyl (meth) acrylate prepolymer, methyl (meth) acrylate , Styrene, vinyltoluene, or other thermosetting resin, or at least one polymerizable monomer as a main component, and if necessary, a curing agent, a curing accelerator, a coloring agent, etc. are added.

After applying the antibacterial coating film component to the mold surface, the thermosetting resin composition is cast, but after the coating film is cured to a semi-cured state, casting is carried out by a so-called gel coat molding method. It can also be carried out, and a more uniform antibacterial surface layer is formed by the gel coat molding method.

As the resin component of the thermosetting resin composition used for casting, at least one of melamine (meth) acrylate prepolymer, epoxy (meth) acrylate, methyl (meth) acrylate prepolymer, and unsaturated polyester resin is used. It is constituted and contains a polymerizable monomer such as methyl (meth) acrylate, styrene and vinyltoluene as required.

As the filler, powders of aluminum hydroxide, silica, causium carbonate, suishuite, glass, etc.,
Particles obtained by crushing the thermosetting resin composition are used. As the colorant, an inorganic pigment is used, but particles of a colored resin cured product are also used.

Due to the effect of the filler and the pigment, the shrinkage rate is lowered, and the dimensional stability and strength are improved. In addition, it is possible to express a stone pattern, and a texture and design similar to marble can be obtained.

The ratio of resin component to filler is generally
20-40 parts by weight of resin component and 80-60 by weight of filler
The range of parts is desirable, but there is a difference depending on the viscosity of the resin, the type and particle size of the filler, etc., and can be appropriately selected.

As the curing agent added to the resin composition of the present invention, an organic peroxide curing agent such as methyl ethyl ketone peroxide is used, and in molding by room temperature curing, a curing accelerator such as cobalt naphthenate is used as a curing accelerator. Agents are used together.

The above-mentioned various materials are mixed by stirring with a mixing device to prepare a resin composition for casting. By mixing with a closed stirring mixer under reduced pressure, bubbles are mixed. Can be prevented.

The resin composition that has been uniformly mixed is poured into a preset mold before the curing reaction occurs, and after curing in a room heated to room temperature or relatively low temperature. , Remove the molded product from the mold. After demolding, the molded product is further heat-cured and cured to obtain the physical properties required as an artificial marble.

The casting mold used in the present invention is made of metal or reinforced plastic, and a mold release agent is applied to the mold surface in advance. The release agent is a method of forming a release film with polyvinyl alcohol, or a method in which a solution of silicone resin, fluororesin, wax, etc. dissolved in a volatile solvent is applied and dried to treat the mold surface for antibacterial treatment. The artificial marble product, which is a molded product coated with a flexible coating, can be easily demolded from the mold.

[0031]

EXAMPLES The parts and% described in the examples below represent parts by weight and% by weight, respectively. Example 1 As an antibacterial agent to be added to a resin solution for coating film for forming an antibacterial coating film on a mold surface, silver zeolite obtained by ion exchange of silver ion and ammonium ion with A type zeolite,
The silver ion in the silver zeolite is 2.5% and the ammonium ion is 1.5%, and the addition amount is 20% with respect to the silver zeolite powder having an average particle diameter of 0.8 μm and the silver zeolite. A zinc oxide-coated silver zeolite powder coated with zinc oxide was used.

A polyvinyl alcohol aqueous solution is applied to the mold surface of an FRP mold for making a vanity counter,
After drying, apply a silicone resin-based mold release agent from above and apply the following coating resin solution to the mold surface on the counter side using a spray gun to a thickness of about 0.5 mm. Then, the coating film was allowed to stand in a room at 30 ° C. for 1.5 hours to gel, and an antibacterial gel coat coating film was formed.

20 parts of a melamine methacrylate prepolymer obtained by condensing melamine, paraformaldehyde and 2-hydroxyethyl methacrylate as a resin liquid for coating film, and fumaric acid, phthalic anhydride, isophthalic acid and propylene glycol are condensed. 0.2 part of the above zinc oxide-coated silver zeolite powder was added to 100 parts of an unsaturated polyester consisting of a 55% styrene monomer solution of the obtained polyester, and further, a methyl ethyl ketone peroxide 55% dibutyl phthalate solution as a curing agent. 5
Parts and 1 part of a 6% cobalt naphthenate styrene monomer solution as a curing accelerator were added and mixed with stirring.

Next, 6 parts of the above-mentioned melamine methacrylate prepolymer, 24 parts of unsaturated polyester, 40 parts of aluminum hydroxide powder, 20 parts of silicic acid anhydride powder, 10 parts of calcium carbonate powder and a curing agent methyl ethyl ketone peroxide 55% dibutyl. 0.4 parts of phthalate solution and 0.2 parts of cobalt naphthenate 6% styrene monomer solution as a curing accelerator were added, and the mixture was stirred for 30 minutes while reducing the internal pressure to Hg 100 mm using a reduced pressure stirring and mixing device,
The mixture is defoamed to prepare a resin composition in a uniform slurry state.

This resin composition was poured into the FRP mold and allowed to stand in a chamber at a temperature of 30 ° C. to cure, then the cast product was removed from the mold, and further heated in a heating and curing chamber at a temperature of 70 ° C. After heating for 4 hours, the after-treatment was performed to obtain a vanity table as an antibacterial artificial marble product.

Comparative Example 1 A coating film on the mold surface was prepared in the same manner as in Example 1 except that the zinc oxide-coated silver zeolite powder in Example 1 was not added to the resin solution for coating film to be coated on the molding mold surface. Forming and casting of the resin composition were carried out to obtain a vanity top plate. Example 1 and Comparative Example 1
The product was tested for antibacterial properties. Table 1 shows the test results.

[0037]

[Table 1]

Test method Antibacterial property, plastic plate antibacterial activity measurement method (shake flask method) is used. 1. Test strain: E. coli IFO 330
1) 2. Preparation of test material: A test piece having a thickness of 5 mm x 1 cm x 1 cm was cut out from a part of the vanity top plate of Example 1 and Comparative Example 1 so that the painted surface would be the surface and used as a test material. 3. Antibacterial activity measurement method: (a) 0.2% of TWEEN 80
The added phosphate buffer solution (E. coli is suspended in PH 7.0 to adjust the number of cells to about 1.0 × 10 ⁶ cells / ml. This number is used as an E. coli test solution. (B) Container with cap Put 30 sheets of the test material in and add 10 ml of the E. coli test solution prepared in (a), (c) Horizontal shaking culture of the E. coli test solution containing the test material in (b) at 25 ° C. for 24 hours and 48 hours, respectively. (Shaking frequency about 150 times / minute) (d)
At the start of the test, after shaking, and after 48 hours, the Escherichia coli test solution containing the test material is subjected to the same test as described above and controlled.

[0039]

EFFECT OF THE INVENTION In the antibacterial artificial marble product obtained by the present invention, the coating film containing the antibacterial agent forms the surface layer of the artificial marble product. Therefore, even if a relatively small amount of the antibacterial agent is added, Sufficient antibacterial effect is obtained. Further, as an antibacterial agent, the silver zeolite powder used in the present invention has silver ions and ammonium ions bound thereto, and the silver ions are incorporated in the skeletal structure of the zeolite, so that elution is extremely small, The antibacterial effect does not decrease over a long period of time. Moreover, discoloration is reduced by the effect of ammonium ions, and the discoloration prevention effect is remarkably improved by coating with zinc oxide, so that the appearance and quality of the product are not affected. Compared with organic antibacterial agents and the like, silver zeolite powder does not cause harm to the human body such as toxicity and is durable, and therefore exhibits a continuous antibacterial effect under hot and humid conditions and environmental conditions that easily pollute.

Since the antibacterial coating layer on the surface is firmly adhered and integrated with the cast resin composition, it is not peeled off by impact or the like. The coating film surface, which is the surface of the antibacterial artificial marble product, contacts the molding die surface and hardens, so that the finished state of the die surface directly becomes the coating film surface finish, and the desired finished appearance is reproduced.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area C08K 9/12 KCR C08L 101/00 // (C04B 26/06 14:36 14:30) 111: 54

Claims (4)

[Claims] 1. A silver zeolite powder having an average particle diameter of 40 μm or less is used as an antibacterial agent on the surface of a casting mold in an amount of 0.05 to 10 μm.
After forming a thermosetting resin coating film containing 1% by weight of the thermosetting resin, a thermosetting resin and a resin composition containing a filler as a main component are injected into the casting mold to cure the cast resin. A method for producing an antibacterial artificial marble product, which comprises depositing and transferring a thermosetting resin coating film on the molding surface of the resin composition. 2. An antibacterial agent comprising silver zeolite powder contained in a thermosetting resin coating film, wherein some or all of the ion-exchangeable ions in the zeolite are replaced with silver ions and ammonium ions. Claim 1 characterized by the above-mentioned.
A method for producing the described antibacterial artificial marble product. 3. The method for producing an antibacterial artificial marble product according to claim 1, wherein 0.05 to 20% by weight of a metal oxide is added to the thermosetting resin coating film. . 4. A melamine (meth) acrylate prepolymer, an epoxy (meth) acrylate, a methyl (meth) acrylate prepolymer, an unsaturated polyester as a resin component in a resin composition which is injected into a casting mold and cured. 4. An inorganic powder component containing at least one selected from the group consisting of aluminum hydroxide, alumina and causium carbonate as a filler. Manufacturing method of antibacterial artificial marble products.