JP2005097337A - Humidity-conditioning and formaldehyde-adsorbing coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein humidity-conditioning performance is hard to be improved because of the tendency of a resin emulsion to form a uniform continuous film and to consequently provide a limited water vapor permeability though a humidity-controlling coating material prepared by formulating a resin emulsion with porous lightweight aggregate is proposed to eliminate formaldehyde- or acetaldehyde-caused sick house syndrome in a newly built or reformed house. <P>SOLUTION: A humidity-conditioning coating material is obtained which is made capable of forming a nonuniform, microporous coating film by using a core-shell structure acrylic resin emulsion as a resin emulsion to improve water vapor permeability and is made markedly excellent in humidity-controlling performances and formalin decomposing and adsorbing performances by using a combination of a humidity-conditioning porous hydrated amorphous silicon dioxide with a formalin-adsorbing and -decomposing agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to humidity control performance and formaldehyde-adsorbing coating material. Specifically, acrylic resin emulsion is used as a binder component, and water-containing amorphous silicon dioxide having moisture absorption / release performance is blended as a porous aggregate. ing. Furthermore, 1,2,3.4-butanetetracarboxylic acid hydrazide is blended as a formaldehyde adsorbent. The present invention relates to a humidity-controlling and formaldehyde-adsorbing coating material in which a coating material containing these is applied to a base such as a wall or ceiling by a coating means such as a trowel, roller, brush or spray.

Conventionally, as a coating material having humidity control properties, a coating material containing diatomaceous earth and polyvinyl alcohol (Japanese Patent Laid-Open No. 3-287672) or a coating material containing diatomaceous earth and a vinyl acetate-acrylic copolymer resin emulsion (special Kaihei 3-287971) has been proposed, but these coating materials have not been sufficiently satisfactory in terms of cost. In addition, with the improvement in the sealing of houses, the concentration of moisture and harmful volatile substances in the living space has increased so much that there have been problems of adverse effects on the human body, such as atopy, allergy, and carcinogenicity. The relationship with is also being pointed out.

As a paint for indoor pollution control that can form a coating film that blocks or absorbs harmful substances such as formaldehyde and plasticizers, from a carbonyl group-containing copolymer emulsion and a hydrazine derivative having a hydrazide group or a semicarbazide group as a crosslinking agent A paint for indoor pollution control (JP-A-10-183023) characterized by blending a resin main component and a solid pigment, powdery or particulate activated carbon, and a harmful substance removing agent such as an amine compound and titanium oxide There has been proposed a coating composition (Japanese Patent Laid-Open No. 10-140045) containing at least one of powdered or fine-particle porous bodies such as activated carbon, sepiolite, and zeolite. However, there is a problem that formaldehyde adsorbed by the porous aggregate is re-dissipated with time.

JP-A-3-287672 JP-A-3-287971 JP 10-183023 A JP 10-140045 Patent No. 3053499

As a result of diligent investigations to solve the above problems, the present inventors formulated a specific acrylic resin emulsion as a binder, and contained water-containing amorphous silicon dioxide and 1,2,3,4-butanetetracarboxylic acid hydrazide. The present inventors have found that the coating material has a high humidity control performance and a high effect of absorbing harmful substances such as formalin, thereby completing the present invention.

That is, the present invention is mainly composed of an acrylic resin emulsion having a core / shell structure in which the glass transition point of the core layer is 0 ° C. or less and the glass transition point of the shell layer is 20 ° C. or more. Amorphous silicon dioxide is blended in an amount of 5 to 15% by weight based on the total solid content, and 1,2,3,4-butanetetracarboxylic acid hydrazide is blended in an amount of 0.05 to 0.5% by weight based on the total solid content. A paint for indoor pollution control is provided, and the paint is applied to the surface of an interior material applied to a floor, a wall surface and a ceiling.

When the vapor permeability of the acrylic resin emulsion having the core / shell structure in the present invention is measured, the vapor transmission amount by the measurement method specified in JISZ0208 is 150 g / m 2 · 24 h or more, and the glass transition point is from room temperature. It was confirmed that an acrylic resin emulsion having a core-shell structure composed of a low core layer and a shell layer having a glass transition point higher than room temperature has an excellent vapor permeability of 200 g / m 2 · 24 h or more.

The reason why the acrylic resin emulsion with a core / shell structure is excellent in vapor permeability is not necessarily clear, but the resin component of the core layer composed of a resin component whose glass transition point is lower than room temperature is involved in film formation, and the glass transition point is Since the shell layer of the resin component higher than normal temperature is dispersed as a broken shell in the coating film, it does not become a uniform continuous film, but micropores are formed in the coating film, and it acts as a vent hole. It is estimated that the permeability becomes high.

A core-shell structure resin emulsion is formed by using a seed particle obtained by emulsion polymerization of an acrylic monomer as a core layer, and an acrylic monomer or the like is emulsion polymerized around it to form a shell layer. Depending on the acrylic monomer employed in the core layer, the acrylic monomer employed in the shell layer, and the like, acrylic resin emulsions having core / shell structures with various properties can be obtained.

Among them, the humidity control coating material of the present invention has a film forming property at room temperature as a coating material, and the shell layer shell can be dispersed as it is in the coating film. An acrylic resin emulsion having a point of 0 ° C. or lower and a glass transition point of the shell layer of 20 ° C. or higher is suitable. If the glass transition point of the core layer is not lower than 0 ° C., film formation in the full season cannot be expected. If the glass transition point of the shell layer is not higher than 20 ° C., it is not preferable because it is difficult for the shell layer to remain dispersed in the summer.

An acrylic resin emulsion having a core / shell structure is, for example, a polymer that forms a shell layer by emulsion polymerization of a hydrophilic vinyl monomer containing a silane monomer to form a shell layer. As a seed particle, an oil-soluble polymerization initiator is added to the emulsion and absorbed in the seed particle, and then a lipophilic monomer is gradually added to the emulsion and absorbed in the seed particle and polymerized in the seed particle. An oleophilic core layer is formed in the seed particles to obtain an acrylic resin emulsion having a core / shell structure.

Examples of the monomer that forms the shell layer include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, methyl methacrylate, and ethyl methacrylate. Other comonomers include styrene, α-methylstyrene, and α-chloro. Examples thereof include styrene and vinyl toluene.

Also, vinyl trimethoxysilane, vinyltrimethoxysilane, vinyl having a polymerizable double bond in the shell layer and hydrolyzable alkoxy groups to improve the water resistance, stain resistance and durability of the coating film. Silane monomers such as triethoxysilane, vinyltriacetoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane You may use together.

As the monomer for the core layer, hydrophilic, for example, 2-ethylhexyl acrylate, isononyl acrylate, decyl acrylate, etc. are used as the main monomer, and other styrene, chlorostyrene, vinyl toluene, vinyl acetate and the like are listed as comonomer. . Also, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane with appropriate amounts of polymerizable double bonds and hydrolyzable alkoxy groups to improve the water resistance, stain resistance, durability, etc. of the coating film. Silane monomers such as vinyltriacetoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyltriethoxysilane are used in combination. Also good.

Known porous aggregates having moisture absorption / release properties include diatomaceous earth, zeolite, sepiolite, Kanuma earth, volcanic ash (Hakushu ash), charcoal, bamboo charcoal, silica gel, and the like. However, the moisture absorption / release performance is inferior to that of water-containing amorphous silicon dioxide. The hydrous amorphous silicon dioxide used in the present invention has a chemical formula of SiO ₂ · nH ₂ O, an average particle size of about 4 to 13 μm, and a pore peak radius of about 3 to 12 nm because of its high moisture absorption / release performance. Suitable for use. This lightweight aggregate is preferably added in an amount of 5 to 15% by weight in terms of total solid content in order to ensure the humidity control performance of the coating material. On the other hand, if it exceeds 15% by weight, the storage stability of the coating material is significantly lowered, which is not suitable.

1,2,3,4-butanetetracarboxylic acid hydrazide used as a formaldehyde adsorbent is an aldehyde-specific catcher agent developed for the purpose of chemical removal of acetaldehyde, and is described in Japanese Patent No. 3053499. The catcher agent is characterized by a chemical bond with aldehydes and no release after formaldehyde adsorption. This catcher agent is preferably added in an amount of 0.05 to 0.5% by weight in terms of total solid content in order to ensure the adsorption performance of formaldehyde. Also, if it exceeds 0.5% by weight, there is no problem, but it is not suitable because the difference in performance becomes small and the cost increases.

As fillers, aluminum hydroxide, calcium carbonate, cinnabar sand, ceramic powder, glass powder, porcelain clay, clay, talc, kaolin, slaked lime, pearlite, magnesium carbonate, etc. with a particle size of about 5 to 300 μm, solid content adjustment, viscosity Blended for adjustment of coating properties, cost adjustment, etc. Among them, aluminum hydroxide includes hydroxyl groups, so the flame retardancy of coating materials can be improved, and since it is white, it is convenient for various toning of coating materials. is there. The blending amount of the filler is suitably 10 to 60% by weight in terms of the solid content of the coating material. If it is 10% by weight or less, the viscosity of the coating material becomes too low, and the coating property is lowered. If it is 60% by weight or more, the viscosity of the coating material becomes too high, and the applicability is lowered.

As a pigment used for coloring, an appropriate amount of titanium oxide, white carbon, iron oxide, bengara, etc. is blended and toned. The pigment particle size is preferably 50 μm or less. When the particle size is 50 μm or more, it is not preferable because the production work is difficult because the particles remain agglomerated and it takes time, and the storage property is deteriorated.

As other compounding materials, a dispersant, an antifoaming agent, an antifungal agent and the like are blended.
As the dispersant, for example, sodium polycarboxylate, ammonium polycarboxylate, organic acid ester-based, ether-based or reactive surfactant, alcohol ethoxy-based or naphthalene-based inorganic salt, etc. are used. Sodium polycarboxylate that does not cause environmental pollution is preferred.

As the antifoaming agent, silica silicone type, polyether type, mineral oil type, metal soap type, polyamide type, modified silicone type, wax emulsion type, etc. can be used, among them from the point of defoaming property and water dispersibility. Mineral oil systems are suitable.

As the fungicides, organic nitrogen sulfur compounds, nitrogen-containing organic cyclic compounds, nitrogen-containing halogen compounds, special urea compounds, etc. are used, among them organic nitrogen sulfur compounds based on mold prevention, sustainability and environmental aspects. Is preferred.

Humidity control and formaldehyde adsorption by adding formaldehyde catcher agent consisting of porous aggregate hydrous amorphous silicon dioxide and 1,2,3,4-butanetetracarboxylic acid hydrazide to highly moisture-permeable acrylic resin emulsion It was possible to obtain a coating material that is extremely excellent in properties and does not release the adsorbed formaldehyde gas. Porous aggregate not only provides humidity control function, but also has formaldehyde adsorption function, and if this coating material is applied as a surface finish on indoor walls, ceilings, etc., excellent humidity control performance And formaldehyde adsorptivity can be exhibited.

Hereinafter, the present invention will be described in detail according to examples and comparative examples. The blending ratio is described in parts by weight. Note that the present invention is not limited to this.

Moisture absorption and desorption test method According to the evaluation method of humidity control performance / the measurement method prescribed by the Japan Finishing Industry Association.
A. Preparation of test body Applying 2 kg / m ^{2 of the} humidity control coating material of Example and Comparative Example to a gypsum board having a thickness of 9.5 mm, a length of 300 mm, and a width of 300 mm, and leaving it in the curing room for 12 days. A test specimen is coated and sealed with a silicone resin sealant and left in a constant temperature and humidity room at a temperature of 20 ± 2 ° C. and a humidity of 45 ± 5% for 48 hours.
B. Test Method After measuring the weight of the test specimen in advance, the specimen is allowed to stand for 24 hours in a thermo-hygrostat adjusted to a temperature of 20 ± 2 ° C. and a humidity of 90 ± 5%, and the weight is measured. Next, after standing for 24 hours in a thermostatic chamber adjusted to a temperature of 20 ± 2 ° C. and a humidity of 45 ± 5%, the weight is measured.
This operation is repeated twice to calculate the moisture absorption / release characteristic value.

Formaldehyde adsorption performance test
Insert a test specimen (effective area 100cm2) into a 5L two-way cock tedlar bag, seal it with a heat seal, suck in the remaining air in the bag, and then inject nitrogen-based formaldehyde gas (about 16ppm). Using a gas detector tube {No.91L made by Gastec Co., Ltd.}, measure the residual gas concentration in the bag over time.

Formaldehyde adsorption / heat release test
Insert a test specimen (effective area 100cm2) into a 1L two-way cock tedlar bag, seal it with a heat seal, suck in the remaining air in the bag, and then inject nitrogen-based formaldehyde gas (about 15ppm). Store at room temperature for 60 hours. Residual gas in the bag is suctioned and replaced with nitrogen gas, heated at 40 ° C for 3 hours, then the gas in the bag is passed through the DNPH collection tube to derivatize the carbonyl compound, and acetonitrile is used. The derivative was extracted and quantitative analysis was performed by HPLC.

Example 1
An acrylic resin emulsion having a core / shell structure, a glass transition point of the core layer of 0 ° C., and a glass transition point of the shell layer of 20 ° C. and a resin solid content of 50% (moisture permeability of 200 g / m 2 · 24 h or more, hereinafter AE1) Hydrous amorphous silicon dioxide {Shionogi Pharmaceutical Co., Ltd., Carplex (registered trademark)}, 1,2,3,4-butanetetracarboxylic acid hydrazide as a catcher agent, water in the mixing container with the formulation shown in Table 1 And mixed thoroughly to prepare a humidity-adjusting formaldehyde-adsorbing coating material.

Comparative Example 1
From the formulation of Example 1, a coating material containing no catcher agent was prepared.

Comparative Example 2
From the formulation of Example 1, a coating material containing no hydrous amorphous silicon dioxide was prepared.

Comparative Example 3
From the formulation of Example 1, water-containing amorphous silicon dioxide and a catcher agent were not contained, and instead, diatomaceous earth was put into a mixing container and thoroughly mixed to prepare a coating material.

Comparative Example 4
From the formulation of Example 1, a coating material was prepared by blending water-containing amorphous silicon dioxide, a general-purpose coating material not containing a catcher agent {moisture permeability of 150 g / m 2 · 24 h or more, JQ-20 manufactured by Aika Industry Co., Ltd.}. .

Table 1 shows the humidity control performance test, formaldehyde adsorption performance test, and formaldehyde adsorption / heat release amount test of Examples and Comparative Examples prepared as described above.

Claims (4)

A moisture-controllable formaldehyde containing a porous aggregate and a formaldehyde adsorbent and having an acrylic resin emulsion as a binder, the acrylic resin emulsion having a core / shell structure Adsorbent coating material. The humidity control property and formaldehyde adsorption according to claim 1, wherein an acrylic resin emulsion having a core / shell structure in which the glass transition point of the core layer is 0 ° C or lower and the glass transition point of the shell layer is 20 ° C or higher is used. Sex coating material. The humidity-adjusting and formaldehyde-adsorbing coating material according to claim 1 or 2, wherein the porous aggregate is mixed in an amount of 5 to 15 wt% in the solid content. The humidity-controlling and formaldehyde-adsorbing coating material according to claim 1, wherein the mixing ratio of the formaldehyde adsorbent is 0.05 to 0.5 wt% in the solid content.