JPH0369936B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a melamine resin decorative board used as a surface material for furniture, building materials, etc. [Prior Art] As a method for improving the design, dimensional change rate, and crack resistance of conventional melamine resin decorative boards, Japanese Patent Application Laid-Open No. 85938/1988 discloses that a melamine resin decorative board is obtained by plasticizing the melamine resin. Disclosed. [Object of the Invention] The present invention involves plasticizing melamine resin as a means for improving the dimensional change rate and cracking resistance of melamine resin decorative boards using melamine resin in all layers, and using the plasticized melamine resin to improve the dimensional change rate and crack resistance of melamine resin decorative boards. The purpose is to obtain a melamine resin decorative board. [Structure of the Invention] In the conventional technology, for plasticizing the melamine resin used in the melamine resin decorative board, a polymer of acrylic ester and/or methacrylic ester is added to the melamine resin obtained by reacting melamine and aldehyde. and methylolmelamine resin and/
Alternatively, the present invention is characterized in that a thermoplastic resin emulsion is mixed with a melamine resin. Specifically, the melamine resin is a thermoplastic resin emulsion with a solid content of 5 to 100 parts by weight per 100 parts by weight of a melamine resin in which 1 mole of melamine is reacted with 1.2 to 3.0 moles of formaldehyde. A composition obtained by mixing the above is used as an impregnating resin for the melamine resin decorative board. Thermoplastic resin emulsions used in the present invention include homopolymerization or copolymerization emulsions of acrylic resins such as methyl acrylate, methyl methacrylate, and acrylic acid methyl ester-styrene, NBR latex, SBR latex, urethane rubber latex, Examples include water-soluble emulsions such as synthetic rubber latex such as silicone rubber latex. The amount of the thermoplastic resin emulsion added is preferably 20 to 60 parts by weight in order to obtain sufficient plasticity and interlayer adhesion.Acrylic emulsion may be added if physical properties such as light resistance are taken into consideration. is preferred. The paper base material used in the present invention is the paper base material used for conventional melamine resin decorative boards.
If the surface layer and the core layer are configured to have the same color, it will be preferable in terms of appearance and design. Furthermore, if printed paper or the like is used as the paper base material of the surface layer, various patterns can be added as desired. The melamine resin decorative board of the present invention is made by laminating a plurality of sheets of melamine resin impregnated paper prepared as described above,
Obtained by hot pressure molding. [Effects of the Invention] In the melamine resin decorative board of the present invention, by adding the thermoplastic resin emulsion to the melamine resin, the distortion of the cured resin is not only reduced compared to the case of using only the melamine resin, but also the melamine resin in the entire resin is reduced. Since the resin content is reduced, the dimensional change rate and crack resistance are improved. Furthermore, since the melamine resin decorative board is constructed as described above, unlike the conventional melamine resin decorative board in which a brown layer of phenolic resin appears, the melamine resin decorative board has the same color from the surface layer to the core material layer, and the surface layer and the core material layer are the same color. Another effect is that a decorative board with excellent design can be obtained by intentionally varying the color of the material layers. Next, the present invention will be explained with reference to Examples. Example 1 1.4 mol of 37% formaldehyde aqueous solution was added to 1 mol of melamine, and the mixture was diluted with sodium hydroxide.
To the melamine resin obtained by adjusting the pH to 9.0 and reacting at reflux temperature for 60 minutes, 40 parts by weight of solids per 100 parts by weight of resin solids, 50% by weight of solids,
An anionic, non-reactive methyl acrylate and methyl methacrylate copolymer emulsion with a viscosity of 100 cps is added and mixed to obtain a plasticized modified melamine resin. The plasticized modified melamine resin has a basis weight of
120g/m ² , white surface paper containing titanium oxide with an ash content of 20% by weight, an impregnation amount of 55% by weight, and a volatile content of 8%.
Seven sheets of impregnated paper were impregnated and dried so that the paper was laminated, a phenol backing plate with leather-like embossing was added, and 25μ aluminum foil was set between the backing plate and the impregnated paper, and the temperature was 130°C. A melamine resin decorative board with a thickness of 1.2 mm is obtained by molding under the following molding conditions: a pressure of 80 Kg/cm ² , a heating pressing time of 30 minutes, and a cooling pressing time of 15 minutes. Example 2 2.0 mol of 37% formaldehyde aqueous solution was added to 1 mol of melamine, and the mixture was diluted with sodium hydroxide.
To the melamine resin obtained by adjusting the pH to 9.0 and reacting at reflux temperature for 45 minutes, a solid content of 40% by weight, which is 50 parts by weight based on 100 parts by weight of the resin solid content, is added.
NBR latex with a viscosity of 150 cps is added and mixed to obtain a plasticized modified melamine resin. The plasticized modified melamine resin is impregnated into the same paper base material as in Example 1 under the same conditions, dried, and molded under the same molding conditions to obtain a 1.2 mm thick melamine resin decorative board. Example 3 White onyx pattern printing paper with a basis weight of 80 g/m ² was impregnated with the plasticized modified melamine resin obtained in Example 1 at an impregnation amount of 30% by weight and a volatile content of 7%, and dried to obtain an impregnated printing paper. is obtained. An overlay impregnated paper of unmodified melamine resin obtained by a conventional method and six sheets of the core-containing paper obtained in Example 1 as a core material layer were laminated by sandwiching the impregnated paper of the printing paper, and the plate was made of a stainless steel mirror. A melamine resin decorative board with a thickness of 1.2 mm was obtained under the same molding conditions as in Example 1 except for using a face plate. Comparative Example 1 In Example 1, the same paper base material as in Example 1 was impregnated with melamine resin without the addition of acrylic emulsion under the same conditions and dried, and molded under the same molding conditions to form a melamine resin makeup with a thickness of 1.2 mm. A board is obtained. Comparative Example 2 In Example 2, a melamine resin without added NBR latex is used to obtain a melamine resin decorative board with a thickness of 1.2 mm. The performances of the melamine resin decorative boards obtained in the above Examples and Comparative Examples are as follows.

[Table] The decorative laminates obtained in the examples show sufficient effects in improving the dimensional change rate and crack resistance, which are the objectives of the present invention. Furthermore, as seen in Example 3, the core material layer does not turn brown due to phenolic resin unlike conventional melamine resin decorative boards, and it matches well with the pattern on the surface, resulting in a high design effect.

Claims (1)

[Claims] 1. Obtained by laminating multiple sheets of melamine resin impregnated paper and molding under hot pressure, the solid content of the melamine resin is 100% by reacting 1.2 to 3.0 moles of formaldehyde to 1 mole of melamine. A melamine resin decorative board characterized in that a composition obtained by mixing 5 to 100 parts by weight of a thermoplastic resin emulsion in terms of solid content is used as an impregnating resin.