JPS60161461A - Top coating agent for decorative sheet - Google Patents

Abstract

PURPOSE:The titled top coating agent, consisting of a specific water-soluble melamine resin, matting agent, a curing catalyst and an aqueous medium, and suitable for surface protection and decoration by application to printed decorative sheet surfaces. CONSTITUTION:A top coating agent consisting of (A) a water-soluble melamine resin consisting essentially of polyethylene glycol-modified melamine, (B) a matting agent, (C) a curing catalyst, e.g. p-toluenesulfonic acid, and (D) an aqueous medium, e.g. water. The top coating agent is applied to a printing base material sheet by a roll coater, gravure coater, etc. The coating weight thereof is preferably 5-20g/m<2> expressed in terms of solid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a top coat agent for various types of decorative sheets, and more specifically, to a top coat agent for various types of decorative sheets, and more specifically, it is a water-based top coat that can be applied to a decorative surface to maintain surface elasticity and beautify. Regarding drugs.

A large number of decorative sheets have been produced in the past, but these decorative sheets are coated with a substrate sheet, which is printed with various types of printing, and then coated with an oil-based liquid mainly based on aminoalkyds. These conventional top coat agents form the top layer.

Firstly, there is a process disadvantage in that a relatively high temperature is required for curing the top coat paint.Secondly, there is a disadvantage in terms of equipment in that a large amount of solvent vapor is generated during drying. The coating film formed on the coating has a strong texture that makes it glare, and even if a matte pigment is used in combination, it has the disadvantage that it is not possible to create a natural surface like that of natural wood. Furthermore, in recent years, three-dimensional patterns have been formed in which the wood III-like conduit portions are formed into concave shapes, but in the case of conventional top coat agents, when known polymerization retardation methods and liquid repellent methods are used, the concave portions are formed in concave shapes. There are disadvantages such as insufficient cutting depth and the need for multiple treatments.

As a result of intensive research in order to solve the above-mentioned drawbacks of the prior art, the present inventor found that when using a certain water-soluble resin paint as a top coat agent in the production of decorative sheets, there are many drawbacks as mentioned above. The present invention was completed by discovering that an excellent decorative sheet can be obtained with sufficient pressure reduction;
This top coating agent for decorative sheets is composed of a curing catalyst and an aqueous medium, and is characterized in that the main component of the water-soluble melamine resin is polyethylene glycol-modified methylol melamine.

To explain the present invention in detail, 1. The water-bathable melamine resin used in the present invention and which mainly characterizes the present invention is a polyethylene resin having a molecular weight of about 100 to 5,000, in which methysel melamine having 3 to 6 methylol groups and 1 mole is mixed with polyethylene resin having a molecular weight of about 100 to 5,000. A water-soluble resin obtained by modifying with glycol, and the matting agent is a conventionally known matte pigment or extender pigment, and any of those conventionally used can be used in the present invention. I can do it. The curing catalyst is a catalyst that crosslinks the melamine resin, and any of various organic or inorganic solid substances can be used, but in the present invention, para-toluenesulfonic acid is preferred. In addition, the aqueous medium is one that has water as its main component and may also contain an organic solvent that is miscible with water such as alcohol.

The essential components of the top coating agent of the present invention are the above-mentioned 9, and each component is about 50 to 80 parts by weight of a water-soluble melamine resin, about 5 to 10 parts by weight of a matting agent, and a curing catalyst in 100 parts by weight of the paint. is preferably used in a proportion of about 10-15 parts by weight. In addition to the above-mentioned components, the top coating agent of the present invention also contains pigments such as titanium oxide, iron oxide (yellow ocher, Bengara, iron black, etc.), polyazo, phthalocyanine blue, phthalocyanine green, quinacridone, and various other additives. They can be added and mixed as needed. In particular, about 0.5 to 2
By including a silicone liquid repellent having a tt degree of water resistance, the adhesive tape removability of the final decorative sheet product can be significantly improved.

The aqueous top coat agent composition of the present invention exhibits particularly remarkable effects when used as a top coat agent for various decorative sheets. That is, conventional amino alkyd oil-based top coat agents.

The top coating agent of the present invention does not select such substrates or printing inks, and is selective to printing inks used to print wood grains and other patterns on base sheets for decorative laminates. It has the advantage that it can be used in combination both with substrates and with printing inks. Furthermore, since the top coat agent is water-based, there is no need for pre-drying or high curing temperatures as with conventional top coat agents, and there are advantages in terms of equipment as there is less generation of solvent vapor. A particularly remarkable effect is the use of a small amount of matting agent, which allows the surface of the coating to have a natural feel similar to that of natural wood. On the other hand, in the case of conventional top coat agents, the surface of the coating film has too much texture, and if a large amount of matting agent is used to weaken this texture, the applicability becomes poor, and the problem of still too strong texture cannot be solved. Met. In addition, when used in the production of conventional decorative sheets with three-dimensional patterns that utilize polymerization retardation and repelling phenomena, in the case of conventional top coat agents, the top coat agent is pre-dried after application to form concave portions. The advantage of the present invention is that the coating film is formed at a relatively low temperature without requiring pre-drying, whereas the cut of the concave portion formed in the corner, which is thermally cured at high temperatures, is insufficient. It has the advantage that very sharp concave portions can be formed without collapse of the concave portions, and in particular, sufficient resistance to cellophane tape peeling can be imparted with one application.

Next, to explain the method for producing a decorative sheet using the top coating agent of the present invention, the base materials used are conventionally known ones, such as various types of paper, processed paper, paper, polyethylene, polyester, etc. Other synthetic resin films or coats, aluminum foils, aluminum sheets, metal materials such as steel plates, various types of wood plywood, or laminates thereof can all be used. Of course, such a substrate sheet may be treated with various base paints or impregnating agents as required.

Next, an arbitrary pattern is printed on the base sheet as described above, but the printing ink for such printing can be used as is, the normal printing ink conventionally used in the production of decorative laminates. A printing method may also be used.

The top coat agent of the present invention is applied onto the printed base sheet obtained as described above, but when producing a three-dimensional decorative sheet in which recesses are formed in the top coat layer, printing may be applied. A substance that retards the polymerization and curing of the top coat agent (
Printing inks (e.g., melamine alkyd-based printing inks) that contain substances that repel liquids (e.g., polymerization inhibitors and polymerization retarders) and top coat agents (e.g., silicone-based liquid repellents)
It is necessary to print synchronously.

In such a case, the present inventor has found that when using the top coating agent of the present invention, an alkaline cutter is good as a polymerization inhibiting or spreading retardant, and as a liquid repellent, an alkaline base of higher fatty acids such as calcium stearate is preferable. It has been found that metal salts are particularly effective. Namely, since the top coating agent of the present invention is aqueous, it acts quickly with a polymerization inhibitor or retardant, and is quickly liquid-repelled by the alkyl group of the higher fatty acid salt.

Further, if necessary, the printed base sheet as described above or the specially printed base sheet as described above can be transferred to the next step, but the base sheet may be made of impregnated material such as paper or processed paper. If this is the case, by impregnating these printing base sheets with a resin impregnating agent such as acrylic resin, urea resin, or melamine resin before topcoat treatment, the peel strength of the printing in the concave areas formed after topcoat treatment can be significantly reduced. We also found that it can be increased.

Next, the top coating agent of the present invention is applied to the printing base sheet as described above, and the top coating agent of the present invention can be coated using a conventionally known method such as a roll coater, a gravure coater, a bar coater, an air knife coater, a flow coater, It can be applied by any method such as a spray coater, and the coating amount is preferably about 5 to 2 Of in terms of solid content. There is no need to pre-dry it after application, for example about 100~1
By heat treating at a temperature of 50° C. for about 30 seconds to 2 minutes, the desired decorative board can be obtained.

Contrary to expectations, the decorative board obtained in this way has excellent surface strength, and the surface has no glare or strong artificial texture, and has a very excellent natural wood-like feel. In the case of three-dimensional decorative sheets that have concave portions on the surface layer, the notches in the concave portions are sharp, creating a more natural look than when conventional top coat agents are used. .

Next, the present invention will be specifically explained with reference to Examples.

Note that the ``-'' or ``-'' in the middle of the first sentence is based on weight.

Example 1 Polyethylene glycol modified methyl etherified methylolmelane resin (polyethylene glycol molecular weight approximately 1
,000) 60 parts, matting agent (Silo()'162)
A top coating agent (1) for decorative boards of the present invention was obtained by mixing 5 parts of /<5 parts of radruene sulfonic acid, 1 part of a water-dispersible silicone liquid repellent, and 30 parts of water.

Example 2 Polyethylene glycol modified methylol melamine resin (
A top coating agent (1) for decorative boards of the present invention was obtained by mixing 60 parts of polyethylene glycol (with a molecular weight of about 700), 8 parts of a matting agent (Syroid 162), 5 parts of paratoluenesulfone IP, and 27 parts of water.

Example 3 Nitro-hetylulose 15 was added to thin paper with a basis weight of 50 t/rt.
Peta printing, blur printing, pattern printing and accent printing were carried out using a conventional printing ink consisting of 40 parts of pigment, 40 parts of pigment, and 45 parts of solvent using a gravure printing method. The entire surface of this printing paper was coated with the aqueous top coat agent of Example 1 using a gravure coating method at 10 f/n? (solid content) applied at a ratio of 150
Dry cured for 30 seconds at °C. The surface of the obtained decorative sheet was neatly leveled without uneven penetration of the top coat agent. When this decorative sheet was bonded to the surface of a particle board using a urea resin adhesive at 150° C. and 5% for 90 seconds, an excellent decorative board was obtained.

Example 4 On titanium base paper with a basis weight of 100 f/wl, solid printing and soft printing were performed using a gravure printing method using a normal gravure ink consisting of 5 parts of cellulose acetate, 20 parts of pigment, and 75 parts of solvent. Next, an ink consisting of 20 parts of styrene maleic acid resin, 30 parts of pigment, 720 parts of triethanol ag, 20 parts of water, and 10 parts of ethylene glycol is used for gravure printing on the areas on the surface of the printing paper where the concave portions are to be formed. Printing was done using this method. After thoroughly drying the ink, apply the top coat agent of Example 2 to the entire printed surface using a reverse coater at 92 Of/rr! (solid content) and heat-cured at 150° C. for 60 seconds. The obtained decorative sheet had an excellent natural wood texture, and the conduit portions of the pattern were sharply cut. In addition, the decorative sheet was coated with a urea resin adhesive at 150°C for 50 minutes.
An excellent embossed decorative board was obtained when it was laminated to particle board under the conditions of 90 seconds and 90 seconds.

Example 5 Peta printing and blur printing were performed on thin paper with a basis weight of 30 seconds 9 using a gravure printing method using a conventional printing ink consisting of 15 parts of nitrocellulose, 40 parts of pigment, and 45 parts of solvent, and then the concave portions of the printed paper were The area to be formed was printed by gravure printing using an ink consisting of 20 parts of melamine resin, 10 parts of alkyd resin, 10 parts of pigment, 45 parts of solvent, 15 parts of paratoluenesulfone W, and 1110 parts of silicon lt.

Next, the aqueous top coat agent of the present invention of Example 1 was applied to the entire surface of the above printing paper using a gravure coating method at a ratio of 109/rl (solid content), and dried and cured at 150° C. for 30 seconds. The surface of the obtained decorative sheet had a very natural wood feel without being too strong, and the conduit portions of the pattern were sharp with sharp cuts. When the decorative sheet was laminated to the surface of a verticle board using a urea adhesive at 150° C. for 5 seconds and 90 seconds, a decorative board with an excellent wood feel was obtained.

Example 6 5 parts of cellulose acetate resin was added to titanium base paper with a basis weight of 80.
Blur printing was carried out using a gravure printing method using a conventional gravure ink consisting of 20 parts of pigment and 75 parts of solvent.

Next, printing was carried out on the surface of the printed matter in which concave portions were to be formed using an ink consisting of 10 parts of a water-soluble resin, 10 parts of calcium stearate, and 70 parts of water using a gravure printing method. After drying the ink, the printing paper is impregnated with an acrylic resin impregnating agent, and after drying, the top coat agent of the present invention of Example 2 is applied to the entire printed surface using a reverse coater at 20 f/n.
? (solid content) and processed in the same manner as in Example 6. As in Example 6, a decorative board having an excellent natural wood feel and uneven texture was obtained.

Claims (1)

[Claims] A top coating agent for decorative sheets, which comprises a water-soluble melamine resin, a matting agent, a curing catalyst, and an aqueous medium, and is characterized in that the main component of the water-soluble melamine resin is polyethylene glycol-modified methylol melamine.