JPS6137108B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a melamine decorative board with excellent post-forming properties. Conventionally, in order to impart post-form properties to melamine decorative boards, the melamine resin used has been modified to impart flexibility.
For example, post-formed decorative boards have been produced by modifying melamine resins with guanamines such as acetoguanamine and benzoguanamine, aromatic sulfonamides, polyhydric alcohols, polyesters, sugars, and the like. It is true that the post-form decorative laminate manufactured in this way has good bending workability, but in recent years, post-form decorative laminates have been widely used as interior material surface panels, and as a result, the design has improved. However, there is a growing demand for smaller bending radii, and the post-form performance of conventional melamine decorative boards is insufficient to meet this demand. It also had drawbacks such as inferior general performance. Therefore, an object of the present invention is to obtain a post-formed decorative board that has excellent general properties such as water resistance, and has better bending workability than ever before. The present invention is characterized by the melamine resin of the melamine decorative board, and the surface paper or pattern paper used in the present invention can be those used for conventional decorative boards. In addition, the base materials such as paper and cloth conventionally used as the core layer and the thermosetting resins coated or impregnated thereon are also phenol resins, epoxy resins, diallyl phthalate resins, polyester resins, melamine resins, etc. What is used for boards is used. Melamine resin to be applied or impregnated on surface paper and pattern paper for decorative laminates is prepared by mixing 1.5 to 3.0 moles of formaldehyde such as formalin or paraform to 1 mole of melamine, reacting with an alkaline catalyst in a conventional manner, and diluting with an organic solvent. Diglycidyl ether, polyglycidyl ether, or monoglycidyl ether is added to the reaction product of melamine and aldehyde obtained by
Weight% (based on the weight of the reactant of melamine and aldehyde) Water-soluble acrylic copolymer emulsion 1~
It is obtained by mixing 30% by weight (based on the weight of the reactant of melamine and aldehyde). The aldehyde/melamine molar ratio is at least
1.5, and when the amount of aldehyde is less than this value, the reaction product of melamine and aldehyde becomes insoluble in water. Also, the molar ratio of aldehyde/melamine is
If it exceeds 3.0, the curing of the resin will proceed more than necessary and sufficient postform properties will not be obtained. Preferably the aldehyde/melamine molar ratio is from about 1.8 to about
It is 2.5. There are various aldehydes, and mixtures thereof may also be used, but formaldehyde is preferred because it is easily available and inexpensive. The amount of diglycidyl ether, polyglycidyl ether, or monoglycidyl ether to be added alone or in any mixture is 1 to the weight of the reactant of melamine and aldehyde.
If it is less than 30% by weight, sufficient post-forming properties cannot be obtained, and if it is more than 30% by weight, the decorative laminate becomes too soft and the resin becomes yellowish and yellows when heated, making it undesirable as a decorative laminate. In order to obtain good and well-balanced general performance, the amount is preferably about 1 to about 10% by weight based on the weight of the melamine and aldehyde reactants. Although these glycidyl ethers may be added during the reaction of melamine and aldehyde, the reaction product requires a short storage time at room temperature, which is not preferred in practice. If the water-soluble acrylic copolymer emulsion is less than 1% by weight based on the weight of the melamine and aldehyde reactants, sufficient post-forming properties cannot be obtained.
If it exceeds 30% by weight, the impregnation of the resin into the surface paper/patterned paper will be poor, making it impossible to obtain a desirable appearance as a decorative board, and the resin liquid itself will become cloudy and the color tone of the decorative board will become whitish, which is undesirable. In order to obtain good and well-balanced general performance, the amount is preferably about 1 to about 15% by weight based on the weight of the melamine and aldehyde reactants. That is, simply adding diglycidyl ether, polyglycidyl ether, or monoglycidyl ether alone or in any mixture thereof to the melamine resin reactant imparts post-form properties to the melamine decorative board obtained using the same, but water-soluble By using this method in combination with acrylic copolymerization, it is intended to further impart post-forming properties to the melamine decorative board. As a result of intensive research in order to impart post-forming properties to melamine decorative boards, the present invention was developed by combining diglycidyl ether, polyglycidyl ether, or monoglycidyl ether alone or in any mixture thereof with an aqueous acrylic copolymer emulsion. I have found that using it is extremely effective. As the melamine resin, in addition to the reaction product of melamine and aldehyde, if a plasticized modified melamine resin obtained by reacting or adding known p-toluenesulfonamide, acetoguanamine, or benzoguanamine is used, the post-form property can be improved. It is even better than the one that uses melamine resin. The amount of paratoluenesulfonamide, acetoguanamine or benzoguanamine added is 0.1 to 1.5 mol per 1 mol of melamine. If it is less than 0.1 mol, processability is poor, and if it exceeds 1.5 mol, insoluble matter will precipitate, making it impossible to obtain a stable melamine resin. Preferably 0.3 to 1 mole of melamine
It is 0.8 mole. A composition obtained by mixing diglycidyl ether, polyglycidyl ether, or monoglycidyl ether alone or in an arbitrary mixture with the melamine resin reaction product obtained as described above is applied to the surface paper and patterned paper for decorative laminates. The impregnated and dried impregnated paper is coated with a thermosetting resin on a base material such as paper or cloth, or the required number of impregnated and dried impregnated papers are stacked on top of a laminate, and a release film, mirror plate, etc. According to the method, a melamine decorative board is obtained by molding and molding by heating and pressurizing. Next, the present invention will be explained based on Examples and Comparative Examples. Example 1 2.0 formaldehyde per mole of melamine
Add mole and adjust the pH to 8.5 to 9.0 with sodium hydroxide, then react at reflux temperature for 40 minutes to produce melamine.
A formaldehyde reactant was obtained. Methyl alcohol is added to obtain a melamine resin with a solid content of 50%, and 5% by weight of diglycidyl ether and 5% by weight of a water-soluble acrylic copolymer emulsion are mixed and stirred to obtain a melamine resin varnish. Overlay base paper (weight 25 g/m ² ) is impregnated with a resin content of 65% and volatile content 7% and dried, and decorative laminate pattern paper (weight 120 g/m ² ) is impregnated with a resin content of 50% and volatile content 7%. It was impregnated and dried so that Next, kraft paper (weight 190 g/m ² ) was impregnated in a normal phenol formaldehyde resin and dried to adjust the resin content to 35% and volatile content to 9% to obtain phenol-impregnated paper. Next, three sheets of this phenol-impregnated paper were stacked, one sheet of resin-impregnated pattern paper and one sheet of resin-impregnated overlay paper were layered one after another on top of this, a mirror plate was set on top of the overlay paper, and molded under hot pressure. Heat pressure and molding conditions are temperature 130
℃, pressure 100Kg/cm ² , heat pressing time 40 minutes, and cooling pressing time 30 minutes to produce a 0.75 mm thick glossy melamine decorative board with good post-forming properties. Example 2 Formaldehyde 2.3 per mole of melamine
Add 0.3 mole of acetoguanamine, adjust the pH to 8.5 with caustic potassium, and react for 60 minutes at reflux temperature. When the cloudiness point at 20°C with respect to water reached 600±50%, 0.2 mol of para-toluenesulfonamide was added, and the reaction was further carried out at reflux temperature for 10 minutes, cooled to room temperature, and methyl alcohol was added. A modified melamine resin with a solid content of 50% was obtained. To this, 3% by weight of polyglycidyl ether and 5% by weight of water-soluble acrylic co-weight emulsion were mixed and stirred to obtain a modified melamine resin varnish, and a resin amount of 55% was applied to pattern paper for decorative boards (wood grain pattern 80g/m ² ). %, and the volatile content was 7%. Two sheets of phenol-impregnated paper obtained in the same manner as in Example 1 were laminated on this, a mirror plate was set on top of the resin-impregnated pattern paper, and the material was hot-pressed and molded in the same manner as in Example 1 to give a gloss of 0.55 mm. A melamine decorative board with good post-forming properties was obtained. Comparative Example 1 In Example 2, only the polyglycidyl ether obtained in Example 2 and the modified melamine resin without mixing the water-soluble acrylic copolymer emulsion were applied to decorative board pattern paper (wood grain pattern 80 g/m ² ) with a resin amount of 55%. It was impregnated and dried to a volatile content of 7%. This was used as a surface layer and molded under hot pressure in the same manner as in Example 2 to a thickness of 0.55mm.
A glossy post-form type melamine decorative board was obtained. Comparative Example 2 Only 3% by weight of polyglycidyl ether was mixed and stirred into the modified melamine resin obtained in Example 2 to obtain a modified melamine resin varnish, which was impregnated and dried in the same manner as in Comparative Example 1, except for the same as in Example 2. A post-form type decorative board was obtained in exactly the same manner. The performance of the decorative boards obtained in the above Examples and Comparative Examples is shown in the following table. 【table】

Claims (1)

[Scope of Claims] 1 A required number of sheets of impregnated paper coated or impregnated with a thermosetting resin and dried on a base material such as paper or cloth are laminated to form a core layer, and a surface layer is formed on top of the core layer for use as surface paper or decorative board. In a melamine decorative board obtained by heating and pressurizing a laminate of patterned paper coated with melamine resin or impregnated with dry impregnated paper, 1.5 to 3.0 moles of formaldehyde per mole of melamine is used as the melamine resin. Add diglycidyl ether, polyglycidyl ether, or monoglycidyl ether alone or in any mixture 1 to 30% by weight (based on the weight of the melamine and aldehyde reactant) to the reactant of melamine and aldehyde, and water-soluble acrylic. 1 to 30% by weight of copolymer emulsion
(based on the weight of the reactants of melamine and aldehyde)
A melamine resin decorative board characterized by using a composition obtained by mixing. 2. Claim 1 in which a modified melamine resin obtained by reacting or adding 1.5 to 3.0 moles of formaldehyde and 0.1 to 1.5 moles of paratoluenesulfonamide, acetoguanamine, or benzoguanamine to 1 mole of melamine is used as the melamine resin. A melamine resin decorative board.