JPS6364476B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing material for artificial veneer boards. Plywood made from precious wood, which is used for furniture, cabinets, interior decoration materials, etc., is being replaced by artificial veneer made from cheaper wood such as South Sea wood due to the shortage of precious wood resources.

However, due to the manufacturing method of artificial veneer boards, the wood grain conduits run deeply perpendicular to the board surface, making it impossible to seal the surface when painting the board. However, when using a conventionally known urethane sealer, it is still not possible to seal the wood grain conduit sufficiently even after repeating the coating three or four times.

Furthermore, Japanese Patent Publication No. 52-42843 describes a sealing method using a putty whose main components are an unsaturated polyester resin and a specific silica powder. ) Transparency after applying putty is slightly inferior due to poor wettability of putty, (b)
Streaks gradually appear on the painted surface during long-term continuous putty coating, and these streaks are difficult to remove even with sanding. (c) The smoothness of the painted surface gradually decreases when scraping the putty with a reverse roll coater. There are various problems such as

As a result of intensive studies to solve these problems, the present inventors have developed an artificial putty whose main components are (a) air-drying unsaturated polyester resin, (b) hydrophobic silica, and (c) zinc stearate. The present invention was completed by discovering that it is excellent as a sealing material for veneer boards.

In the present invention, (a) air-drying unsaturated polyester resin includes trivalent alcohol monomers such as trimethylolpropane and glycerin, tetrahydric alcohol monomers such as diallyl ether, pentaerythritol, diglycerin, and ditrimethylolpropane;
Mono-hexavalent alcohols such as di, triallyl ether, dipentaerythritol, and sorbitol,
Known products containing air-drying components such as allyl ether compounds such as di-, tri-, tetra-, and pentaallyl ethers, tetrahydrophthalic anhydride and its derivatives such as tetrahydrophthalic anhydride, entomethylenetetrahydrophthalic anhydride, and dicyclopentadiene derivatives. However, it is desirable to use tung oil, linseed oil, soybean oil, cottonseed oil, safflower oil, coconut oil, tall oil, and their fatty acids as resin components in order to improve the impregnation and coating properties of conduits. Further, a small amount of epoxy acrylic resin, polyester acrylic resin, or urethane acrylic resin that has good compatibility with the air-drying unsaturated polyester resin may be used in combination.

The air-drying unsaturated polyester resin is used as a vinyl monomer solution. The ratio of the air-drying unsaturated polyester resin to the vinyl monomer is appropriately determined so that the viscosity of the filler putty is in the range of 10 ⁴ to 5×10 ⁵ centipoise. Such vinyl monomers include styrene, vinyltriene, vinyl acetate, vinyl chloride, (meth)acrylic acid ester, methylenebisacrylamide,
Examples include diallyl phthalate, triallyl isocyanate, trimethylolpropane methacrylate, glycidyl methacrylate, vinylcyclohexene monooxide, and 2-hydroxymethacrylate glycidyl ether.

When curing the filler putty after application in the present invention is carried out by heating in a hot air drying oven, far infrared ray irradiation, etc., a combination of a radical polymerization initiator, a metal soap, an amine, an amine salt, etc. as a curing catalyst,
For example, methyl ethyl ketone peroxide and cobalt octoate or cobalt naphthenate, cumene hydroperoxide and cobalt naphthenate,
Appropriate amounts of benzoin peroxide, manganese octoate, etc. are added to a vinyl monomer solution of an air-drying unsaturated polyester resin when preparing putty.

In addition, when performing ultraviolet curing by irradiation with a low-pressure mercury lamp, fluorescent lamp, medium-pressure mercury lamp, high-pressure mercury lamp, etc., use benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl disulfide, etc. as a photoinitiator. Tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, benzoyl peroxide,
Acetophenone, 2,2-dimethoxy2-phenylacetophenone, 2,2-diethoxyacetophenone, benzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, etc. are used in combination.

(b) Hydrophobic silica in the present invention is colloidal silica in which the silanol group is substituted with an alkyl group, and has an average particle size of ~20×10 ^-7 cm and an apparent specific gravity of approximately 40 to 60 g/. be. As a commercially available product
It is known as AEROSIL R-972 (Japan Aerosil product). By using this hydrophobic silica, the cured coating film has high transparency.
It satisfies the requirements that a putty should have, such as being thixotropic and easy to apply, having good wettability to wood grain conduits, having high transparency, having great sealing properties for wood grain conduits, and leaving no bubbles in the cured coating film.

The blending ratio of the (b) hydrophobic silica and (a) unsaturated polyester resin is approximately 4 to 15 parts by weight per 100 parts by weight of the unsaturated polyester resin, and the viscosity of the filler putty is 10. The amount of other ingredients is determined to be in the range of ⁴ to 5×10 ⁵ centipoise. Hydrophilic silica can also be used in an amount within about 50% by weight based on hydrophobic silica.

Next, (c) the amount of zinc stearate is approximately 1 part by weight per 100 parts by weight of (i) unsaturated polyester resin.
~5 parts by weight, and in this case also, an appropriate amount is used so that the viscosity of the filler putty falls within the range of 10 ⁴ to 5×10 ⁵ centipoise, as described above. Zinc stearate imparts thixotropic properties to the putty. It has functions such as improving polishability without reducing the transparency of the cured coating film and improving the sealing effect of conduits.

The sealing material of the present invention is obtained in the form of a putty by kneading the above-mentioned components using a triple roll or the like. Using this putty, first apply the artificial veneer using a natural roll coater at a relatively slow speed of 10 to 30 m/min while expelling air from inside the conduit. Next, use a reverse roll coater for 3~
Excess putty is scraped off at a speed of 10 m/min, and the amount of putty applied is approximately 2 to 15 g/ ^shaku2 . According to the above application method, a sufficient sealing effect can be obtained by applying up to two times. When curing by ultraviolet irradiation after application, it is desirable to internally cure the pot life of the putty by using a peroxide catalyst or a polyisocyanate in combination, taking into account the fast curing speed and the light-shielding area. Also, before applying putty, if you use a small amount of urethane sealer or quick-drying urethane acrylic paint as a primer to prevent tar from forming on the artificial veneer, a beautiful finish can be obtained.

When curing the artificial veneer after applying putty by irradiating it with ultraviolet rays, use a high-pressure mercury lamp, medium-pressure mercury lamp, single irradiation, or a combination of a low-pressure mercury lamp and a fluorescent lamp. 30 to 60 seconds with high pressure mercury lamp, medium pressure mercury lamp (80W/cm)
Then, irradiate for about 2 to 6 seconds. When curing by heating, stacking can be performed in a heating furnace or by far-infrared irradiation at a temperature of 40 to 70°C for 5 to 15 minutes.

The surface of the artificial veneer plywood sealed in this way is polished to make it even smoother. Next, a top coat of wax type, non-wax type polyester resin paint, acrylic resin paint, alkyd resin paint, urethane polyester resin paint, acrylic urethane resin paint, amino alkyd resin paint, nitrocellulose lacquer, etc. is applied to this polished surface. Apply. This results in an artificial veneer with high transparency, smoothness, and depth.

Next, the present invention will be specifically explained with reference to Examples. In the examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 Gocerac #780 (air-drying styrene solution of unsaturated polyester resin: manufactured by Nippon Gosei Kagaku Kogyo) 100
0.5 parts of cobalt octoate, 10 parts of hydrophobic silica (AEROSIL R-972 manufactured by Nippon Aerosil Co., Ltd.), and 3 parts of zinc stearate were added to the mixture, and the mixture was kneaded with two passes on a three-roll roll to form a transparent filler putty. I got it. The viscosity of this putty is 2 x 10 ⁴ centipoise (B
type viscometer (6 rpm).

Add Permek N (MEK Peroxide 55) to the putty.
% solution) at a ratio of 1% by weight, this was applied to artificial veneer plywood using a natural coater (application roll 30 rpm, feed roll 30 rpm), and then a reverse roll coater (scraping roll 10 rpm,
When the excess putty was scraped off using a feed roll (30 rpm), the coating amount was 4 g/ ^shaku2 and the coated surface was smooth.

After leaving this at room temperature for 1 hour, heating it at 60℃ for 10 minutes to cure it, and polishing the coated surface with #320 sandpaper, no pinholes were observed.
It turned out that the seal was complete. Furthermore, a polysanding paint based on Goceramic #750 (air-drying unsaturated polyester resin manufactured by Nippon Gosei Kagaku Kogyo) was spray-painted on top of it at a rate of 30 g/ ^shaku2 , and immediately placed in an oven at 60°C to heat cure. No foaming was observed from the painted surface, and it was confirmed that the sealing was complete, and the resulting artificial veneer plywood was highly transparent and had an excellent sense of depth.

Example 2 Goceramic #785 (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.:
Air-drying unsaturated polyester resin styrene solution)
100 parts, 3 parts of benzoin isopropyl ether,
Add 8 parts of AEROSIL R-972 and 4 parts of zinc stearate, knead with 2 passes on a triple roll,
A transparent filler putty was obtained. The viscosity of this putty is 4
×10 It was ⁴ centipoise.

After adding 5 parts of DeSmodyl L-75 to 100 parts of this putty and kneading it thoroughly, artificial veneer plywood was coated in the same manner as in Example 1, and the amount of coating was 3.5 g/ ^shaku2 .
The coated surface was smooth. This painted board was immediately cured by irradiating it with a high-pressure mercury lamp for 30 seconds (27W/cm x 4 lamps, conveyor speed 2m/min), and when the coated surface was polished with #320 sandpaper, no pinholes were observed. It turned out that the seal was complete.

Furthermore, apply 20g/ ^shaku2 of polysanding paint on top of that.
Spray paint at a ratio of was confirmed.

Control Example 1 Artificial veneer plywood was coated with a known urethane sealer using a natural coater at a ^rate of 3 g/square, and after being left overnight, the urethane sealer was further coated for 3 cycles. Then, after sanding with #320 sandpaper, the polysanding paint of Example 1 was spray-painted at a rate of 30 g/ ^shaku2 .
When it was heated and cured in an oven at 60°C, bubbles with a diameter of 0.3 to 1.0 mm were generated all over the painted surface.

Control Example 2 In place of the hydrophobic silica in Example 1, 50 parts of talc (Nitsu Talc: Nippon Talc Products) and OH-type silica (AEROSIL #380: Nippon Aerosi Products) were used.
A putty was obtained in the same manner as in Example 1 using 3 parts.
The viscosity of the putty was 5×10 ⁵ centipoise.

Using this putty, artificial veneer plywood was applied in the same manner as in Example 1, and after curing, polysanding paint was applied. As a result, almost no pinholes were observed, but the transparency was poor and there was no sense of depth. .

Claims (1)

[Scope of Claims] 1. A sealing material for artificial veneer boards consisting of a putty whose main component is (a) air-drying unsaturated polyester resin (b) hydrophobic silica (c) zinc stearate.