JP2013052591A - Protective coating film of emulsion coating and ceramic decorative sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a decorative sheet finished with an emulsion coating material using a ceramic substrate as a base is inferior to a conventional decorative sheet finished with a urethane coating material in surface hardness, contamination recovery properties, chemical resistance and solvent resistance, when making the use for the interior.SOLUTION: A UV clear coating film of 7-25 μm is formed as protective coating of an emulsion coating film. As for a method for forming the coating film, UV clear coating is applied uniformly in the amount of 15-25 g/mby using a rubber roller which is engraved in the shape of streaks at equal intervals in the density of 80 lines/inch by means of laser engraving, and is subjected to setting for about one minute. The UV protective coating film is hardened by being irradiated with ultraviolet rays having a main wavelength of 360 nm by 500-700 MJ/cm.

Description

  The present invention relates to a method for forming a protective coating film that compensates for the shortcomings of emulsion paints, which are water-based paints, and a decorative board having a protective film.

  In recent years, environmental pollution of organic solvents has been strongly pointed out, and water-based coatings and weak solvent UV curing (hereinafter, UV is described as UV) have progressed. In the building industry, coating materials for exterior applications are often used in weather-resistant emulsion paints such as acrylic silicone emulsion and high weather-resistant acrylic emulsion, while interior building materials have a performance different from weather resistance, that is, Emphasis is placed on chemical properties, contamination resistance, contamination recovery, solvent resistance, and surface hardness. Weather resistant emulsion paints used in exterior applications do not have sufficient performance for these performances. In order for emulsion paints to be widely used in interior applications such as factories, clean rooms and stores, these drawbacks must be remedied.

Japanese Patent No. 4478780 JP 2010-222229 A

  The surface of the ceramic substrate was treated with an impregnated sealer and UV curing sealant, and after polishing the surface, a water-based acrylic emulsion paint was applied using a roll coater and a flow coater, dried, and then coated with an acrylic emulsion. A decorative board was obtained. Since this decorative board is finished with emulsion paint, no organic solvent is used, but it is inferior in hardness, solvent resistance, chemical resistance, and stain resistance compared to conventional urethane paint finish, such as factory, store, clean room, etc. It cannot be used for parts with high required performance, and the range of use is limited. These disadvantages must be compensated for in order to be able to be used in parts with high required performance.

  Performances such as emulsion paints being weak against organic solvents, dye-based colorants soaking in the coating film and becoming unwieldy, and soft surface hardness are inherent properties of emulsion paints. In order to compensate for these properties, it is an effective means both technically and economically to form a dense UV-cured film as a protective film. A thin film is a film thickness of 7 micrometers-25 micrometers. A film thickness of 7 to 25 μm is a suitable film thickness as a protective coating film. That is, when the film thickness is less than 7 μm, it is difficult to form a uniform film and sufficient hardness cannot be obtained. On the other hand, when the film thickness is 25 μm or more, the soft emulsion coating film is cracked or peeled by shrinkage when the UV coating film is cured. The 7 μm to 25 μm-thickness UV clear film exhibits a sufficient function as a protective coating for emulsion coatings in terms of solvent resistance, chemical resistance, contamination resistance, and hardness.

Next, a UV clear coating method with a film thickness of 7 μm to 25 μm will be described. As the paint, a solventless UV (paint trade name UVO2200G5) manufactured by ICA is used. The relationship between the coating amount of the UV paint and the film thickness is approximately 25 g / m ² and 25 μm for the solventless paint. In the case of a water-based UV coating, the solid content is 37 μm and the thickness is 9 μm at 25 g / m ² . When the coating amount is 20 g / m ² to 25 g / m ² , the film thickness is 20 μm to 25 μm for a solventless paint, and 7 μm to 9 μm for a solid content of 37%.
As the coating method, among the methods described in Japanese Patent No. 4478780, a grooved roll having the shape shown in FIG. 3 (rubber hardness 60 °, groove density 80 / 吋, groove pitch (p) 0.32 mm n / m = Fig. 4 is a schematic diagram showing the relationship between the roll coater and the substrate at the time of coating, where the thickness of the calcium silicate plate is g. The interval t between the grooved roll and the backup roll is t = g−1.5, so when coating a 6 mm thick calcium silicate plate, g = 4.5 mm, and set at room temperature for 1 minute after coating. Thereafter, a cured film was obtained by passing under a three UV lamps having a main wavelength of 360 nm and an output of 80 W / cm at a line speed of 10 m / min and irradiating with UV rays of 500 MJ / cm ² .

Next, the painting method of water-based UV clear is described. The paint is UVA911G5 (solid content 37%) of ICA (Italy). The coating is applied in the manner shown in paragraph (0006) with a grooved roll shown in FIG. 3 at 20 to 25 g / m ² . Set in an atmosphere of 50 ° C to 60 ° C for 1 minute to evaporate the water in the coating and pass under three UV lamps with an output of 80 W / cm with a main wavelength of 360 nm at a line speed of 10 m / min. Then, UV irradiation of 500 MJ / cm ² was performed to obtain a cured film. The film thickness at this time was 7 μm to 9 μm.

A test plate for performance evaluation shown in Table 1 was prepared. The test board preparation details are shown below.
On the surface of a calcium silicate plate (substrate name: Ecolux manufacturer name: NICHIAS, size: 910 × 1820 × 6 mm, specific gravity: 0.8), potassium silicate 20% silica 3% lithium nitrite 0.2 % Of inorganic impregnating solution (trade name: Kotobuki Primer K, manufacturer: Kotobuki Kogyo Co., Ltd.) dissolved in water, and 100 g / m ² was applied and impregnated with a sponge roll coater after being diluted with water. Dried for minutes.

Next, using a reverse roll coater, an ultraviolet curable sealant (trade name: AC-12, maker name: DIC, 165 g / m ² ) is applied and rubbed. Then, it was passed through a UV lamp with an output of 80 W / cm having a main wavelength of 360 nm and irradiated with UV at 350 to 400 MJ / cm ² to be cured. The surface was subjected to a smooth polishing finish by attaching # 240 and # 280 sandpaper to a double wide belt sander.

After the polishing, the plate surface temperature is preheated to 50 to 55 ° C., and a water-based acrylic emulsion paint (trade name: Walla White FC manufacturer name: NATCO Co., Ltd.) is 110 g / m ² using a roll coater and a flow coater. After coating and setting for 3 minutes, it was dried by passing it through a jet dryer set at 80 ° C., 100 ° C., and 120 ° C. for 3 minutes, and the surface temperature was lowered to 40 ° C. or less, and then stacked. In this way, a painted plate was made without using any organic solvent. Let this acrylic emulsion finish decorative board be [A] (FIG. 1).

Curing type clear (trade name: UVO2200G5, manufacturer name: ICA (Italy)) was applied at 25 g / m ² , set, and cured by UV irradiation. The decorative board thus obtained is designated as [B] (see FIG. 2).

Next, a method for preparing a water-based paint test plate will be described.
Section 0010 (the surface of the decorative board [A] obtained in paragraph (0010) is treated with the method described in paragraph (0007) and aqueous UV clear (trade name: UVA911G5, manufacturer name: ICA (Italy)) is 20 g / Then, m ^{2 was} applied, setting and UV irradiation were carried out, and the decorative board thus obtained was designated as [C].

Table 1 shows the hardness, solvent resistance and stain resistance of each of [A], [B] and [C] and the comparative example.
As a comparative example, a decorative calcium silicate board (trade name: clean panel manufacturer: Kotobuki Kogyo Co., Ltd.) finished with acrylic urethane enamel was similarly tested and listed in Table 1.
In the solvent resistance evaluation, the degree of change is observed after 6 hours after coating with a watch glass drop.
In the stain resistance evaluation, a line is drawn with a width of 2 cm and wiped with various chemicals after 2 hours.

  Judging from Table 1, the 7 μm to 25 μm UV clear thin film functions as a protective coating for the emulsion coating. That is, in the solvent resistance test, [A] was slightly glossy, but [B] and [C] were not changed. It was good compared with the urethane coating film of the comparative example. The surface pencil hardness [A] was HB to F and the comparative example was H, but [C] was equivalent to the comparative example and [B] was 2H, which was better than the comparative example. Regarding the stain resistance, the results of red ink and red crayon were the same as or better than the comparative example. Regarding the oil-based magic, the neutral detergent did not dissolve the magic and could not be wiped off, but if it was wiped off using xylene, all of [A], [B], [C] and the comparative example were wiped off. From the above results, the acrylic emulsion alone was inferior to the current acrylic urethane enamel in solvent resistance, stain resistance, and surface hardness. However, the current solvent-based coating was formed by forming the UV clear of the thin film of the present invention as a protective film. It was found that the performance equivalent to or better than the membrane can be obtained.

  As described above, since the organic solvent is not used in the manufacturing stage, the organic solvent is not evaporated in the drying stage, so that the working environment and the global environment are not deteriorated. In addition, the disadvantages of emulsion paints are that the surface is soft, scratches easily, dirt easily penetrates, dirt soaked is difficult to wipe off, softens easily with various organic solvents, chemical resistance is weak, etc. It is removed with a UV clear protective film. 7-25μm thin film has good adhesion to emulsion coating, and has a conventional acrylic urethane enamel finish that can withstand the harsh use conditions of factory interiors, store interiors, clean rooms, etc. It can be used in the same way as calcium silicate board.

Cross section of acrylic emulsion finish decorative calcium silicate board [A] Sectional view [B] of an acrylic emulsion-finished decorative calcium silicate board with a protective coating according to the present invention The schematic sectional drawing which shows the front view and groove shape of the groove roll coater used for this invention. Side view of roll coater during painting.

  The present invention provides a base treatment using a conventional organic solvent in which an isocyanate-impregnated sealer using an organic solvent, which has been conventionally used as a base treatment, is applied to reinforce the base material and performs a sealing treatment using UV sealing. Although it is effective for the method, it is considered that it will be beneficial in the future to perform the surface treatment using the substrate reinforcing method described in JP 2010-222229 A as a countermeasure against environmental pollution without using any organic solvent. . Next, an example of a production method that does not use an organic solvent will be described.

Example 1
Inorganic impregnating agent (trade name: Kotobuki primer) described on the surface of a calcium silicate plate (trade name: Ecolux specific gravity 0.8 manufacturer name: Nichias Co., Ltd.) having a size of 910 mm × 1820 mm × 6 mm as a ceramic building material : Potassium silicate 20%, Silica 3%, Lithium nitrite 0.2%, Water approx. 77% Manufacturer name: Kotobuki Kogyo Co., Ltd.) is diluted twice with water and 100 g / m ² is sponge roll coater And dried with hot air at 60 ° C. for 1 minute. Next, a solventless UV sealant (trade name: AC-12, manufacturer: DIC Corporation) is applied using a reverse coater so as to rub 165 g / m ² . Immediately after that, the sealant is cured by irradiating 350 to 400 MJ / cm ² with an ultraviolet lamp having an output of 80 W / cm having a main wavelength of 360 nm. The surface is polished with a double wide belt sander equipped with sandpaper of # 240 and # 280, the polishing powder is removed with a brush, and the ground treatment is completed by a method not using an organic solvent. Next, the polished surface is preheated to 55 ° C. to 60 ° C., and a water-based acrylic emulsion paint (trade name: for Walla White FC, manufacturer name: NATCO Co., Ltd.) is 110 g / m ² using a roll coater and a flow coater. Apply. After coating, set at room temperature for 3 minutes to adjust the surface coating, then pass through a jet dryer with 3 zones set at 80 ° C, 100 ° C and 120 ° C for 3 minutes to dry, then pass through the cooling zone to the surface The material temperature is set to 40 ° C. or lower and accumulated. Next, using a grooved roll having a density of 80 / 吋 shown in FIG. 4 described in Japanese Patent No. 4478780, a solvent-free UV clear (product name: UVO2200G5 manufacturer) with a roll interval of 4.5 mm for a plate thickness of 6 mm Name: ICA (Italy)) 20 g / m ² applied, UV light of 600 MJ / cm ² is irradiated with an UV lamp with an output of 80 W / cm having a main wavelength of 360 nm to obtain a protective film by curing the surface. It was. This embodiment is a manufacturing method that is gentle to environmental pollution that does not use any organic solvent from the base treatment to the formation of the protective film.

(Example 2)
A ground treatment is carried out in the same manner as in Example 1, and subsequently an aqueous acrylic emulsion paint is similarly applied and dried. The plate temperature at the outlet of the drying furnace is set to be 30 ° C. to 40 ° C., and a water-based UV paint (trade name: UVA911G5, manufacturer name: ICA (Italy)) is applied. The coating method is performed by the method described in Japanese Patent No. 4478780, and a grooved roll having a density of 80 / inch shown in FIG. 4 is used and the roll interval is set to 4.5 mm, and 20 g / m ^{2 is} applied for 120 seconds. During the setting, water was evaporated and the coating was leveled, and passed through an ultraviolet lamp having a main wavelength of 360 nm, and irradiated with ultraviolet rays of 600 MJ / cm ² to cure the surface. This paint is a water-based UV paint with a solid content of 37% and 63% water. Therefore, the coating thickness of 20 g / m ² is about 7 μm. This method is also an environmentally friendly manufacturing method that does not use any organic solvent as a solvent from the base treatment to the formation of a protective coating film.

  Since it is a coating that does not use any organic solvent, it does not deteriorate the working environment or the global environment. Moreover, since VOC does not remain in a base material, it can be used immediately after construction. The product is suitable for interior decoration and renovation materials for schools and nursing homes. It can also be used in places with high required performance such as clean rooms.

DESCRIPTION OF SYMBOLS 1 Calcium silicate board 2 Impregnation sealer layer 3 Sealing layer 4 Enamel layer 5 Protective coating layer 6 Grooved roll 7 Backup roll 8 UV curable transparent clear paint d Groove depth g Thickness m Groove concave part n Groove convex part p Groove pitch t Roll interval

Claims (4)

  The surface of ceramic base materials such as calcium silicate boards and fiber reinforced cement boards is treated with an impregnated sealer and UV-curing sealant, and the surface is polished to create a smooth paint base, followed by an aqueous emulsion. A ceramic decorative veneer characterized in that a paint is applied and colored, and an ultraviolet curable transparent clear is formed on the surface as a protective layer.   2. The ceramics decorative board according to claim 1, wherein the impregnation sealer is water-based, and the ultraviolet curable transparent clear is water-based or solvent-free.   The ceramics decorative board according to claim 1 or 2, wherein a thickness of the protective coating layer made of the ultraviolet curable transparent clear is 7 to 25 µm.   The coating means for the protective coating layer is a roll coater composed of a coating roll and a receiving roll, and the coating roll is formed with grooves by laser engraving at a density of 80 / inch, and the receiving roll corresponding to the coating roll. The manufacturing method of the ceramics type decorative board of any one of Claims 1-3 which set the space | interval with a roll to board thickness-(1.5mm-2.0mm), and apply | coat the said ultraviolet curing transparent clear. .