JPS6360691B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to decorative laminates using paper impregnated with thermosetting resins, particularly melamine-formaldehyde resins.

Conventionally, a so-called melamine decorative board is known in which a base paper having good permeability is impregnated with a thermosetting melamine/formaldehyde resin, and then laminated onto a base material and cured by heating and pressure. Also known is a technique of printing a pattern on base paper in advance to create a decorative board having a surface-resistant pattern. Furthermore, in order to further enhance the design of this surface, many techniques have been proposed to intentionally create unevenness or differences in gloss. In particular, providing unevenness or differences in gloss that are in sync with the pattern can dramatically enhance the design of the surface, and the following methods have been proposed and partially put into practical use.

A typical method is to use a shaping material such as metal or film during hot press to create irregularities or differences in gloss on the surface of the decorative board. However, in this method, it is generally difficult to accurately synchronize the pattern and the surface condition, and although it is a simple and stable method, it is difficult to achieve a sufficient effect in terms of design. A similar method for forming unevenness on the surface and matching it with the pattern is to apply a coloring agent only to the concave areas after forming the unevenness on the surface during hot-pressing, for example,
There is a so-called wiping method in which ink is applied to the entire surface and then the ink is scraped off on the convex parts, but this method has production problems such as low mechanical stability and the ink is exposed on the surface of the concave parts. As a result, the surface properties, which are one of the characteristics of melamine decorative boards, are partially degraded, which is a disadvantage in physical properties.

A method for forming surface irregularities without using a forming plate is to use a foaming ink or the like to foam the impregnated paper or during hot press to give only those areas a different surface shape. Proposed. However, with this method, it is not possible to express fine details, and there is not only a problem with the color stability of the concave portions, but also the foamed portions tend to deteriorate physically. A method has also been proposed in which defects in the physical properties of the surface are improved by removing this area by polishing or other methods after foaming, but this method requires a removal process after pressing, resulting in lower productivity and higher costs. An increase in the number of people is inevitable.

Methods for synchronized embossing include the so-called chemical embossing method, which changes the hardening speed of the resin and takes advantage of the difference in shrinkage, or a method that uses liquid repellent ink to coat the surface with liquid resin and create recesses in that area. Although these methods have been proposed, the effect of unevenness by these methods is hardly seen under the conditions of hot press, and it is difficult to say that they are effective methods.

The present invention was made in order to eliminate these drawbacks, and relates to the production of a melamine decorative board having a surface roughness and density that matches the design using an inexpensive and simple method. In the production of melamine decorative boards, which are printed, impregnated with an aqueous solution of melamine/formaldehyde resin, dried, then placed on a base material and hardened and molded by heat and pressure, inks containing basic substances and By using normal ink and using low-pressure melamine/formaldehyde resin as the impregnation resin, the glossy state of the part surface corresponding to the pattern created by the ink containing the basic substance is different from the glossy state formed by the surface of the mirror plate. A method for producing a melamine decorative board characterized by fastening, and
We provide various methods to make this more effective.

By printing on base paper with good permeability using normal ink and ink on the acidic side or alkaline side, impregnating it with a thermosetting resin promoted by an acid curing agent, pressurizing and heating it, the difference in gloss can be achieved. A method for expressing is disclosed in Japanese Patent Application Laid-Open No. 54-45376, but the inventors of the present invention specifically studied this method and concluded that it is still unsatisfactory in terms of expression effect and stability. Ta. That is,
In the case of acidic inks, there is less gloss change compared to alkaline inks, and due to additives that are liquid at room temperature such as liquid organic amines and mineral acids,
When adjusting the pH or using highly water-soluble additives such as alkali metal hydroxides, the pattern may bleed or block during the printing process, or elution into the impregnating resin aqueous solution during impregnation. lack of stability of the resin solution due to the impregnation, unevenness due to elution and movement of additives as the aqueous impregnating resin solution moves on the base paper during impregnation,
Migration of additives during pressurization and heating causes defects such as gloss blurring, and it is recognized that it is necessary to overcome such defects with additives and inks in order to stably obtain sharp effects. I came to have it. As a result of considering these points, we found that in order to produce a melamine decorative board that has a sharp effect and a difference in surface condition that is stable and in sync with the pattern, based on the principle shown above,
As an additive, it is a stable basic compound that is solid in the range from room temperature to heat processing temperature, has low solubility in water and impregnating resin, and has no deliquescent property that can be easily dispersed in the ink, especially alkaline earth metals. It was discovered that hydroxide is effective, and that a thermoplastic resin that is highly hydrophobic and melts when heated and pressurized is most suitable as an ink binder, rather than the commonly used cellulose binder. reached completion.

That is, the gist of the present invention is to apply a pattern to a base paper with good permeability using an ink containing a basic substance as a pattern ink and a normal ink, and after impregnating and drying a melamine/formaldehyde resin aqueous solution, the base paper is coated with a pattern. The difference in the surface condition in sync with the pattern is achieved by placing the ink on top and hardening and molding it by applying pressure and heating to make the surface corresponding to the ink containing the basic substance different from the surface formed by the mirror plate. In the method for producing a melamine decorative board having This is a method for producing a melamine decorative board, characterized in that a highly hydrophobic thermoplastic resin whose softening point is lower than the heating temperature during curing and molding is used as a binder for an ink containing a basic substance.

As a base paper with good permeability, a paper containing titanium of about 80 to 120 g/m ² is usually used, but there is no particular limitation. Desirably, from the life of the impregnated paper when impregnated with melamine resin, and the stability of the difference in surface condition during curing.
It is preferable to use so-called neutral paper with a pH of around 7. Normal inks may be oil-based or water-based with cellulose binders, which are generally used for printing on impregnated paper, as long as they do not significantly impair resin penetration and adhesion with base paper and other overprinting inks. There are no particular limitations. The base material is typically a wood-based material such as particle board, but it may be of any material as long as it has the properties required as a product and is compatible with the process, and may be molded at the same time as the impregnated paper is laminated. Melamine/formaldehyde resin is used as the impregnating resin. The acid curing agent (including a latent curing agent) may be one commonly used as a curing agent, and of course may contain a penetration aid and other additives as necessary. Typical melamine/formaldehyde resins include low-pressure melamine, which is used for molding at pressures of about 15 to 25 kg/ ^cm2 , and fast-curing types, which are characterized by short molding times. In Although,
There are no particular limitations on the purpose of the present invention, and the equipment,
You can choose according to your conditions.

As basic substances, strong inorganic alkalis such as typical alkali metal hydroxides, and organic amines such as monoethanolamine and ethylenediamine are unsuitable, and they are not suitable for use in thermal environments ranging from room temperature to molding temperatures.・Basic compounds that are chemically stable and have virtually no deliquescent property or water solubility, especially Mg
Hydroxides of alkaline earth metals such as (OH) ₂ , Ba(OH) ₂ and Ca(OH) ₂ are suitable.

The melamine decorative board manufactured by the method of the present invention can be produced by a simple method without substantially changing the conventional manufacturing process, and has a surface that stably has a three-dimensional effect that is in sync with the pattern, with almost no increase in price. Especially in terms of wood grain patterns, it becomes a beautiful decorative board that visually resembles the real thing, and is used in a wide range of applications such as furniture, interior decoration, walls, ceilings, and floors. Examples are shown below.

Example 1 On 80g/m ² titanium-containing acid-free paper, print a wood grain pattern blur plate and bone plate with ink using a normal cellulose binder, and then print a conduit plate with ink of composition 1 below. A base paper for impregnation was created by printing. This is impregnated with an aqueous solution of melamine/formaldehyde resin for ordinary low-pressure melamine decorative laminates containing acid hardeners and penetrants, dried, and then
Prepare impregnated paper containing resin equivalent to 150% of the weight, place it on a 9 mm thick particle board, stack a 70% glossy mirror plate and cushion material in order, and heat the mirror plate to 150%
It was pressed for 4 minutes at a temperature of 20 kg/cm ² and then cooled.

Composition 1 Binder: Vinyl chloride/vinyl acetate
Copolymer (≒800) 18 parts by weight Additive: Calcium hydroxide 20 Solvent: Methyl ethyl ketone/toluene
86 〃 Pigment Appropriate amount As a result, a melamine decorative board with a three-dimensional effect and a surface with a matte conduit portion was obtained.

Example 2 A tile pattern was printed on 80 g/m ² titanium-containing acid-free paper with an ink using a normal cellulose binder and an ink with the following composition 2, and then a normal fast-curing type melamine decorative board resin was printed on this. Impregnated with aqueous solution and dried at 120℃ for 3 minutes to 160% of base paper weight
Create impregnated paper containing resin equivalent to the weight and make it 9mm thick.
The glossy mirror plate was heated to 150°C in advance and layered with the cushion material ^.
After pressing for 50 seconds, it was immediately taken out and cooled.

Composition 2 Binder: Vinyl chloride/vinyl acetate/
Acrylic copolymer (≒760)
15 parts by weight Additive: Magnesium hydroxide 18 〃 Solvent: Methyl ethyl ketone 80% Toluene 20% 88 〃 Pigment Appropriate amount As a result, the luster of the joints printed with composition 2 ink disappears and the other parts become glossy three-dimensional. A tile-like melamine decorative board with a nice feel was obtained.

Example 3 On 100 g/m ² titanium-containing acid-free paper, the blurred and boning versions of the wood grain pattern were printed with ink using a normal cellulose binder, and the conduit version was printed with ink of composition 3, and then the normal paper was printed. Impregnated paper was prepared by impregnating and drying an aqueous solution of melamine/formaldehyde resin for low-pressure melamine decorative boards so that the weight of the resin after drying was 170% of the base paper. This impregnated paper was layered on top of a chip sheet containing wood chips and a urea resin curing agent, which had been temporarily pressed after mixing, and a 70° glossy mirror plate and cushion material were layered one after another and pressed at 150℃ at 20kg/cm ² for 6 minutes. After cooling, it was taken out. As a result, the gloss of the conduit part disappeared and a surface-decorated chipboard having a three-dimensional effect that matched the wood grain pattern was obtained.

Composition 3 Binder: Vinyl chloride/vinyl acetate
Copolymer (≒800) 18 parts by weight Additives: Barium hydroxide 20% Calcium hydroxide 80% 22 Solvent: Methyl ethyl ketone 80% Toluene 20% 86 Pigment Appropriate amount

Claims (1)

[Claims] 1. A pattern is created on base paper with good permeability using normal ink and ink containing a basic substance that is solid in the range from room temperature to molding heating temperature and is not water-soluble or deliquescent. A method for producing a melamine decorative board, which is characterized in that it is coated, then impregnated with an aqueous solution of melamine/formaldehyde resin, dried, placed on a base material, and hardened and molded by hot pressing using a mirror plate. 2. The method for producing a melamine decorative board according to claim 1, characterized in that an alkaline earth metal hydroxide is used as the basic substance. 3. The method for producing a melamine decorative board according to claim 1, characterized in that a thermoplastic or thermosetting resin that is hydrophobic and has a property of softening below the molding temperature is used as the binder for the ink containing a basic substance. 4. The method for producing a melamine decorative board according to claim 3, characterized in that a thermoplastic resin mainly composed of vinyl chloride/vinyl acetate copolymer is used as the binder for the ink containing a basic substance.