JP4562582B2 - Paint finishing method - Google Patents

Description

  The present invention relates to a method for finishing a wooden substrate.

  Many wooden base materials are used on wall surfaces, doors, window frames, and the like inside buildings such as houses, and various types of coating are performed for the purpose of protecting the surface and dressing. Wood base coatings can be broadly classified into transparent and opaque coatings. Among these, when opaque coating is performed, there is a feature that it can be finished in a free color according to preference.

  As an opaque coating method for a wood base material, a method is known in which a sanding sealer is applied and the surface of the coating film is polished, and then a top coating material is applied (for example, Japanese Patent Publication No. 6-51170). According to the coating method using such a sanding sealer, a finish with high smoothness can be obtained. Furthermore, since uneven suction during coating of the top coat material is suppressed, a uniform appearance can be achieved.

  By the way, in recent years, in buildings such as houses, the airtightness of the room has been increased due to the change of the architectural style, etc., but on the other hand, there is a concern about the indoor environmental pollution by volatile organic compounds (VOC). Such indoor environmental problems are being considered as social problems, and various ministries and agencies are also examining guidelines on VOCs, usage restrictions, and the like.

Against this background, low VOC is also demanded for the paint used for painting the above-mentioned woody base material. In order to meet the demand, it is necessary to secure the film-forming property while reducing the amount of VOC added as a film-forming aid or the like. In general, as one method for ensuring such film-forming properties, a method is known in which the glass transition temperature of a resin is lowered by adjusting the type and ratio of monomer components used in a synthetic resin emulsion. However, with this method, the adhesiveness of the coating film surface to be formed increases, and particularly with respect to the sanding sealer, there arises a problem that workability in the polishing process of the coating film is deteriorated.
On the other hand, if the amount of powder blended in the sanding sealer is increased, the polishing property can be improved to some extent. However, since the woody base material has a property of easily expanding and contracting due to changes in temperature, humidity, etc., increasing the amount of powder in the sanding sealer causes a problem that the formed coating film is likely to break.

Japanese Examined Patent Publication No. 6-51170

  The present invention has been made in view of the above-described problems. In a painting finishing method in which a sanding sealer is applied to a wooden base material and a coating material is applied after polishing the coating film, the sanding sealer is applied. An object of the present invention is to obtain a coating method capable of achieving a low VOC while preventing the occurrence of cracks in the coating film without causing any hindrance to the polishing workability.

  As a result of intensive studies to achieve the above object, the present inventor has come up with a coating finishing method using a sanding sealer containing a combination of specific inorganic powders, and has completed the present invention.

That is, the present invention has the following characteristics.
1. For wood base
(1) Synthetic resin emulsion (A), an inorganic powder (B) having an average particle diameter of 100 μm or less and a Mohs hardness of 2 or more, an average particle diameter of 1 to 200 μm, and the inorganic powder ( A scale-like inorganic powder (C) having an average particle size larger than B) and a Mohs hardness of less than 2 is included as an essential component, and the pigment volume concentration of the inorganic powder (B) is 1 to 20%, and the scales The pigment volume concentration of the fibrous inorganic powder (C) is 20 to 60%, and the volume ratio of the inorganic powder (B) to the scaly inorganic powder (C) is 50:50 to 2:98. Paint a sanding sealer with a volatile organic compound content of less than 5% by weight,
(2) After polishing the surface of the coating film formed by the sanding sealer,
(3) A paint finishing method characterized by coating a water-based top coating material in which the content of a volatile organic compound in the paint is less than 5% by weight.
2. The coating finishing method according to 1., wherein the synthetic resin emulsion (A) in the sanding sealer is a cross-linking reaction type synthetic resin emulsion.

  According to the present invention, in the paint finishing method of applying a sanding sealer to a wooden base material and applying a top coating material after polishing the coating film, without affecting the polishing workability after sanding sealer coating, Low VOC can be achieved while preventing cracking of the coating film.

  Hereinafter, the best mode for carrying out the present invention will be described.

[Sanding sealer]
As the sanding sealer in the present invention, the synthetic resin emulsion (A), the inorganic powder (B) having an average particle size of 100 μm or less and a Mohs hardness of 2 or more, and the average particle size of 1 to 200 μm, What contains the scaly inorganic powder (C) whose average particle diameter is larger than the said inorganic powder (B) and whose Mohs hardness is less than 2 is used as an essential component.

Among these, a synthetic resin emulsion (hereinafter referred to as “component (A)”) serves as a binder, and as a monomer component constituting the resin, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl ( (Meth) acrylic acid esters such as (meth) acrylate;
Carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid or its monoalkyl ester, itaconic acid or its monoalkyl ester, fumaric acid or its monoalkyl ester;
Contains amino groups such as N-methylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminoethyl vinyl ether, N- (2-dimethylaminoethyl) acrylamide, N- (2-dimethylaminoethyl) methacrylamide monomer;
Hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate;
Nitrile group-containing monomers such as acrylonitrile and methacrylonitrile;
Amide group-containing monomers such as acrylamide, methacrylamide, maleic acid amide, N-methylol (meth) acrylamide and diacetone acrylamide;
Epoxy group-containing monomers such as glycidyl (meth) acrylate, diglycidyl (meth) acrylate, and allyl glycidyl ether;
Carbonyl group-containing monomers such as acrolein, diacetone (meth) acrylamide, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone;
Alkoxysilyl groups such as vinyltrimethoxysilane, vinyltriethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane Containing monomers;
Vinyl ester monomers such as vinyl acetate and vinyl propionate;
Aromatic monomers such as styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene;
Vinylidene halide monomers such as vinylidene chloride and vinylidene fluoride;
Examples include ethylene, propylene, isoprene, butadiene, vinyl pyrrolidone, vinyl chloride, vinyl ether, vinyl ketone, vinyl amide, and chloroprene. These can be used alone or in combination of two or more. As the component (A) of the present invention, an acrylic resin emulsion using at least one (meth) acrylic ester among the above monomer components is suitable.

  (A) The minimum film forming temperature of a component is 10 degrees C or less normally, Preferably it is 5 degrees C or less, More preferably, it is 0 degrees C or less. When the minimum film-forming temperature of the component (A) is within such a range, a low VOC type sanding sealer suitable for interior finishing can be obtained. And in this invention, even if it is a case where a synthetic resin emulsion with such a low minimum film forming temperature is used, sufficient polishability can be ensured. Moreover, if minimum film forming temperature is in the said range, the followable | trackability with respect to expansion / contraction of a wooden base material can also be improved.

In this invention, abrasiveness can be improved more by using a crosslinking reaction type synthetic resin emulsion as (A) component. In addition, coating film properties such as water resistance and adhesion can be improved.
Examples of the crosslinking reaction include a carboxyl group and a metal ion, a carboxyl group and a carbodiimide group, a carboxyl group and an epoxy group, a carboxyl group and an aziridine group, a carboxyl group and an oxazoline group, a hydroxyl group and an isocyanate group, a carbonyl group and a hydrazide group, and an epoxy group. Combinations of hydrazide groups, epoxy groups and amino groups, hydrolyzable silyl groups and the like can be mentioned. Among these, preferable crosslinking reactions include a carboxyl group and an epoxy group, a carboxyl group and an oxazoline group, a carbonyl group and a hydrazide group, and an epoxy group and a hydrazide group.
The form of the cross-linking reaction type synthetic resin emulsion includes (1) a synthetic resin emulsion having a reactive functional group and a cross-linking agent capable of reacting with the reactive functional group, (2) the reactive functional group, and the reaction Any of synthetic resin emulsions having both functional groups capable of reacting with functional groups.

  Although the manufacturing method of (A) component is not specifically limited, For example, emulsion polymerization, soap-free emulsion polymerization, dispersion polymerization, feed emulsion polymerization, feed dispersion polymerization, seed emulsion polymerization, seed dispersion polymerization, etc. are employable. Among these, if a polymerization method in which the component (A) is a multilayer structure type emulsion (core-shell type emulsion or the like) is employed, it is effective in achieving both polishing properties and crack prevention properties. (A) The average particle diameter of a component is about 0.05-0.2 micrometer in general.

In the sanding sealer of the present invention, the inorganic powder (B) (hereinafter referred to as “component (B)”) having an average particle diameter of 100 μm or less and a Mohs hardness of 2 or more is used as the inorganic powder. A scaly inorganic powder (C) (hereinafter referred to as “component (C)”) having an average particle diameter of 1 to 200 μm, an average particle diameter larger than that of the component (B), and a Mohs hardness of less than 2 is used in combination. Furthermore, the pigment volume concentration of the component (B) is 1 to 20%, the pigment volume concentration of the component (C) is 20 to 60%, and the volume ratio of the component (B) to the component (C) is 50:50 to 2:98. Use both ingredients so that
In the present invention, by controlling the particle diameter, hardness, shape, and mixing ratio of the inorganic powder in this way, excellent polishing properties and crack prevention properties can be ensured.
The average particle diameter in the present invention is a median diameter measured by a laser diffraction particle size distribution measuring apparatus (for example, “SALD-2100” manufactured by Shimadzu Corporation).

The component (B) is not particularly limited as long as the average particle diameter and the Mohs hardness are within a predetermined range, and a known inorganic powder can be used. Examples of such component (B) include titanium oxide, barium sulfate, calcium carbonate, kaolin clay, calcined clay, slaked lime, calcium hydroxide, dolomite, zeolite, wollastonite, and quartz sand.
As the component (B), those having a Mohs hardness of 3.0 or more and 8.0 or less are particularly preferable, and those having a Mohs hardness of 5.0 or more and 7.0 or less are more preferable. When the hardness of (B) component is too small, there exists a possibility that grindability may fall. The Mohs hardness in the present invention is a value measured using a Mohs hardness meter (where diamond is 10). Although the shape of (B) component is not specifically limited, Usually, it is granular.
(B) The average particle diameter of a component is 100 micrometers or less normally, Preferably it is 0.1-30 micrometers, More preferably, it is 0.2-10 micrometers. When the average particle size of the component (B) is too large, the abrasiveness tends to decrease. Moreover, it becomes difficult to obtain a coating film with high smoothness.

Examples of the component (C) include iron oxide, talc, wax, graphite, etc. Among these, an inorganic powder whose particle shape is scaly can be used. Such a shape of the component (C) plays an important role in securing excellent polishing properties and crack prevention properties.
Although the Mohs hardness of (C) component is less than 2.0, Preferably it is 0.5 or more and less than 2.0, More preferably, it is 1.0 or more and 1.5 or less. When the hardness of the component (C) is too large, it is difficult to ensure sufficient physical properties in terms of polishing properties and crack prevention properties.
The average particle size of the component (C) is 1 to 200 μm, preferably 2 to 100 μm, more preferably 3 to 50 μm. In particular, the average particle size of the component (C) is desirably 3 times or more (more preferably 5 to 100 times) the average particle size of the component (B). If a component having such an average particle size is used as the component (C), it is possible to further improve the polishing properties and crack prevention properties.

  In the present invention, the mixing ratio of the component (B) is adjusted so that the pigment volume concentration is 1 to 20% (preferably 2 to 18%, more preferably 3 to 15%). The mixing ratio of the component (C) is adjusted so that the pigment volume concentration is 20 to 60% (preferably 25 to 55%, more preferably 30 to 50%). Furthermore, the volume ratio of the component (B) and the component (C) is 50:50 to 2:98 (preferably 40:60 to 5:95, more preferably 30:70 to 10:90). When the ratio of the component (B) and the component (C) is out of such a range, it becomes difficult to achieve both abrasiveness and crack prevention.

  In the sanding sealer in the present invention, the component (A) is used as a binder, but a resin component other than the component (A) can be used in combination as a binder as necessary. Examples of such a resin component include water-soluble resins such as polyvinyl alcohol, cellulose derivatives, acrylic resins, and polyurethane resins.

  The sanding sealer of the present invention can contain components other than the above-described components as long as the effects of the present invention are not significantly impaired. Examples of such components include coloring pigments, extender pigments, aggregates, fibers, thickeners, leveling agents, wetting agents, plasticizers, antifreezing agents, pH adjusting agents, antiseptics, antifungal agents, and antialgae. Agents, antibacterial agents, adsorbents, dispersants, antifoaming agents, adsorbents, ultraviolet absorbers, antioxidants, catalysts, crosslinking agents and the like. If necessary, a film-forming aid and other volatile organic compounds can be mixed, but the content thereof is preferably less than 5% by weight, more preferably less than 1% by weight in the paint.

[Paint finishing method]
In the present invention, the base material to be painted is a wooden base material in a wall surface, a door, a window frame, a ceiling, a beam, a pillar or the like inside a building. Examples of the wood base material include beech, cypress, too much, artificial materials such as teak and lauan, laminated wood / laminate, ordinary plywood, wood fiberboard / particle board, and the like. These may be flame retardant treated.

In the present invention, the sanding sealer is first applied to such a wooden substrate.
In painting the sanding sealer, a known painting device can be used. For example, a spray, a roller, a brush, a trowel, a spatula, or the like can be used as the coating instrument. Among these, a roller or a brush is preferable.
The coating amount of the sanding sealer may be appropriately set according to the coating instrument to be used, the desired surface shape, etc., but is usually 0.05 to 0.5 kg / m ² , preferably 0.1 to 0.2 kg / m is ^2. It is also possible to dilute the paint with water during painting.

In the present invention, after the coating film of the sanding sealer is dried, the coating film surface is polished. The sanding sealer may be painted and dried at ordinary temperature (about 5 to 35 ° C.), and the drying time may be about 3 to 48 hours.
In the present invention, a smooth base surface can be formed by this polishing treatment. In particular, in the present invention, a highly smooth base surface can be easily obtained. In addition, the labor spent for the polishing process can be reduced.
The polishing process may be performed by a known method using abrasive cloth or the like. What is necessary is just to select the particle size of abrasive cloth suitably according to a desired smoothness degree. Two or more types of abrasive cloth can be used for the treatment. The powder generated by polishing may be removed by air blow or waste.

  After the polishing process, the top coat material is applied. In the present invention, as the top coating material, an aqueous top coating material in which the content of the volatile organic compound in the paint is less than 5% by weight (preferably less than 1% by weight) is used. By using such a water-based top coating material, it is possible to suppress total VOC generation in the entire coating process.

  As the water-based top coating material, for example, a glossy synthetic resin emulsion paint specified in JIS K5660, a synthetic resin emulsion paint specified in JIS K5663, or the like can be used. Examples of the binder for the aqueous topcoat material include a vinyl acetate resin emulsion, an alkyd resin emulsion, an epoxy resin emulsion, an acrylic resin emulsion, a urethane resin emulsion, an acrylic silicon resin emulsion, a fluororesin emulsion, and a composite system thereof. These can be used alone or in combination of two or more. These binders may have crosslinking reactivity, and when a binder having crosslinking reactivity is used, the water resistance and chemical resistance of the coating film can be improved. Further, by using a multilayer structure type emulsion such as a core-shell type emulsion as these binders, it is possible to improve film-forming properties, crack prevention properties, stain resistance and the like.

The gloss level of the water-based top coating material is not particularly limited, and may be any of a matte type, a three-minute gloss type, a semi-gloss type, a gloss type, etc., and should be appropriately selected according to a desired finished appearance. Can do. In particular, in the present invention, the lower layer sanding sealer can also exert the effect of relaxing the expansion and contraction of the wood base material. Therefore, even if a water-based coating material of a type in which the pigment volume concentration is increased and the gloss is reduced is used. The cracking of the film can be suppressed. The pigment volume concentration of such an aqueous top coat is usually about 30 to 80% (preferably 40 to 70%).
The color tone of the water-based top coating material is not particularly limited, and can be freely selected according to a desired finish feeling.

In the application of the water-based top coating material, known coating instruments such as sprays, rollers, and brushes can be used. The coating amount of the aqueous top coating material is usually about 0.1 to 0.4 kg / m ² . It is also possible to dilute the paint with water during painting. The drying time of the aqueous topcoat material is usually about 3 to 48 hours at room temperature.

  Examples are given below to clarify the features of the present invention.

(Manufacture of sanding sealers)
200 parts by weight of synthetic resin emulsion 1, 30 parts by weight of inorganic powder 2, 220 parts by weight of flaky inorganic powder, 220 parts by weight of water, 10 parts by weight of dispersant, 6 parts by weight of thickener, Sanding sealer [1] was produced by mixing and stirring 4 parts by weight of a foaming agent by a conventional method.
Next, sanding sealers [2] to [8] were produced according to the formulation shown in Table 1.
In addition, the following were used as a raw material in sanding sealer manufacture.

Acrylic resin emulsion 1: Non-crosslinked acrylic resin emulsion (methyl methacrylate-2-ethylhexyl acrylate-acrylic acid copolymer, solid content 50 wt%, minimum film forming temperature 0 ° C. or less)
Acrylic resin emulsion 2: Cross-linked acrylic resin emulsion (methyl methacrylate-2-ethylhexyl acrylate-diacetone acrylamide-acrylic acid copolymer, cross-linking agent: adipic acid dihydrazide, solid content 50% by weight, minimum film forming temperature 0 ° C. or less )
Inorganic powder 1: Titanium oxide (average particle size 0.3 μm, Mohs hardness 6.0, specific gravity 4.2)
Inorganic powder 2: heavy calcium carbonate (average particle diameter 4 μm, Mohs hardness 3.0, specific gravity 2.6)
Scale-like inorganic powder: talc (average particle size 10 μm, Mohs hardness 1.0, specific gravity 2.7)
・ Dispersant: Polycarboxylic acid dispersant ・ Thickener: Urethane thickener ・ Defoamer: Silicone defoamer

(Test Example 1)
Sanding sealer [1] is applied to a 90 × 45 cm plywood board at a coating amount of 0.15 kg / m ² , dried in standard conditions (temperature 23 ° C., relative humidity 50%) for 24 hours, and then the coating surface is coated. Polishing was performed with # 240 sandpaper, and the polishing powder was sufficiently removed by air blow. Next, a pale yellow acrylic resin emulsion paint (JIS K 5663 applicable product, VOC content less than 1%, pigment volume concentration 48%) was applied at a coating amount of 0.3 kg / m ² and cured in a standard state for 168 hours.
By the above method, a smooth colored finish surface could be obtained. Further, there was no difficulty in the sharpening operation in the polishing treatment, and the sharpened surface was flat, and the polishing workability was generally good. The test specimen thus obtained was subjected to a total of 10 cracking resistance tests with a cycle of "Leave for 24 hours at 23 ° C and 90% relative humidity → Leave for 24 hours at 50 ° C and 5% relative humidity". The state of the coating film was observed, but no abnormality such as coating film cracking was observed.

(Test Example 2)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [2] was used instead of the sanding sealer [1]. As a result, the polishing workability was good and a smooth colored finished surface could be obtained. Abnormalities such as coating film cracking were not observed in the crack resistance test.

(Test Example 3)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [3] was used instead of the sanding sealer [1]. As a result, the polishing workability was good and a smooth colored finished surface could be obtained. Abnormalities such as coating film cracking were not observed in the crack resistance test.

(Test Example 4)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [4] was used instead of the sanding sealer [1]. As a result, the polishing workability was good and a smooth colored finished surface could be obtained. Abnormalities such as coating film cracking were not observed in the crack resistance test.

(Test Example 5)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [5] was used instead of the sanding sealer [1]. As a result, a smooth colored finish surface could be obtained. Polishing workability was even better than Test Examples 1-4. Abnormalities such as coating film cracking were not observed in the crack resistance test.

(Test Example 6)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [6] was used instead of the sanding sealer [1]. As a result, a smooth colored finish surface could be obtained. Polishing workability was even better than Test Examples 1-5. Abnormalities such as coating film cracking were not observed in the crack resistance test.

(Test Example 7)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [7] was used instead of the sanding sealer [1]. In Test Example 7, a smooth colored finish surface could be obtained, but the polishing workability was inferior to Test Examples 1-6.

(Test Example 8)
Coating was performed in the same manner as in Test Example 1 except that the sanding sealer [8] was used instead of the sanding sealer [1]. In Test Example 8, a smooth colored finish surface could be obtained, but the polishing workability was inferior to Test Examples 1-6. Further, in the crack resistance test, a part of the coating film was cracked.

Claims (2)

For wooden substrates
(1) Synthetic resin emulsion (A), an inorganic powder (B) having an average particle diameter of 100 μm or less and a Mohs hardness of 2 or more, an average particle diameter of 1 to 200 μm, and the inorganic powder ( A scale-like inorganic powder (C) having an average particle size larger than B) and a Mohs hardness of less than 2 is included as an essential component, and the pigment volume concentration of the inorganic powder (B) is 1 to 20%, and the scales The pigment volume concentration of the fibrous inorganic powder (C) is 20 to 60%, and the volume ratio of the inorganic powder (B) to the scaly inorganic powder (C) is 50:50 to 2:98. Paint a sanding sealer with a volatile organic compound content of less than 5% by weight,
(2) After polishing the surface of the coating film formed by the sanding sealer,
(3) A paint finishing method characterized by coating a water-based top coating material in which the content of a volatile organic compound in the paint is less than 5% by weight.   2. The paint finishing method according to claim 1, wherein the synthetic resin emulsion (A) in the sanding sealer is a cross-linking reaction type synthetic resin emulsion.