JPH0327678B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing reinforced paper that is used for furniture, interior decoration materials, etc. by being bonded to plywood, particle board substrates, etc. (Prior art) Synthetic resin decorative boards using plywood, particle board, etc. as substrates are decorative paper impregnated with melamine resin, urea resin, phenol resin, etc. on the surface of the substrate, or decorative paper impregnated with or painted with unsaturated polyester resin. Conventionally, decorative boards have been used by applying paper and applying heat and pressure to form a single piece. In recent years, in addition to these, a type of decorative paper called ``Finished Oil'' has been manufactured in which decorative paper is impregnated with resin in advance to strengthen the paper spacing, and if necessary, a top coat is applied. It becomes a decorative board just by laminating it, which greatly simplifies the lamination process. Generally, the method for making these finishing oils is to print on paper with good permeability, then impregnate it with a mixture of acrylic resin and melamine resin, and dry it. In other words, by mixing a relatively flexible acrylic resin and a hard and permeable melamine resin at a certain ratio, a reinforced paper with a certain flexibility and interpaper strength is made. It is what it is. (Problems to be Solved by the Invention) The method of applying decorative paper impregnated with melamine resin or urea resin to the surface of the substrate and applying heat and pressure has the drawback that it requires many steps, costs, and special equipment when producing the decorative board. have. In addition, the method of using Finnish Dofu oil is as follows:
Since the mixed resin of acrylic resin and melamine resin is exposed on the surface of the paper, crosslinking of the melamine progresses over time, and after a certain period of time, it becomes impossible to laminate the paper to the substrate using ordinary vinyl acetate adhesive. It has a fatal flaw. Further, as the melamine hardens, the paper becomes brittle, resulting in problems such as paper breakage during lamination or post-processing. In addition, in order to solve these problems, it is possible to reduce the crosslinking property by lowering the mixing ratio of melamine resin to acrylic resin. Due to the decrease in the strength of the paper itself, it is no longer possible to obtain sufficient inter-sheet strength as a reinforced paper. Also, if the amount of acrylic resin is increased, the paper quality will become too flexible.
When it is attached to a base material, irregularities on the surface of the base material occur on the surface of the decorative board, which tends to cause so-called "eye discoloration". The present invention solves the above-mentioned drawbacks of the prior art and provides a method for producing reinforced paper that improves the deterioration of adhesion suitability over time. (Means for Solving the Problems) The structure of the present invention is such that in a method of manufacturing reinforced paper by impregnating decorative base paper or decorative paper with good permeability with a mixed solution of acrylic resin emulsion and melamine resin, the resin is mixed. A composition in which 10 to 50 parts by weight of a polyvinyl acetate resin emulsion with an average particle size of 20 μ or more is added to the liquid in terms of solid content per 100 parts by weight of the solid content of the mixed liquid is applied from the back side of the decorative base paper or decorative paper. This is a method for producing reinforced paper characterized by impregnation. The present invention will be explained in more detail below. As decorative paper or base paper with good permeability,
Decorative paper with a printed pattern on titanium paper with a size degree of 5 seconds or less, non-size paper, etc., or decorative base paper before printing is used. In general, the basis weight of the paper may be 30 to 80 g/ ^m2 , which is used as base paper for building materials, but since it is coated and impregnated with a water-based resin, it is desirable that the paper has a wet strength of 200 g/15 mm or more. The impregnating resin used in the present invention is an acrylic emulsion with good impregnating properties that has been conventionally used for finishing oils.
Polyacetic acid with an average particle size of 20μ or more per 100 parts by weight of resin solid content of the mixed solution to which 20 to 100 parts by weight of water-soluble melamine resin as a crosslinking agent is added per part by weight It is made by adding 10 to 50 parts by weight of a vinyl emulsion resin and diluting it with water or the like to a desired viscosity of about 10 centipoise to 500 centipoise. The present invention consists of applying and impregnating the above-described impregnating resin from the back side of the decorative paper or decorative base paper with good permeability at a resin solid content of 50 to 200 parts by weight per 100 parts by weight of the paper. As the coating method, known methods such as gravure coating, roll coating, and air knife coating can be selected. In addition, the reinforced paper obtained by the method of the present invention is
If necessary, print using a known method in the post-process,
It is also optional to perform post-processing such as top coating. (Function) By impregnating decorative paper or decorative base paper with resin from the back side as described above, the acrylic emulsion resin and melamine resin with small particle sizes penetrate into the inside of the paper and form the outer layer on the back side. A resin layer mainly composed of vinyl acetate resin with large particle size is formed on the paper. (Effects) Since the present invention has the above configuration and operation, it has the following effects. Since a layer mainly made of vinyl acetate resin is formed on the back surface, it is possible to adhere to the base material with the vinyl acetate resin even after a long period of time has passed after coating and impregnating the resin. Since there is a layer mainly made of vinyl acetate resin on the back side, even if the melamine inside the paper layer crosslinks over time and the paper becomes hard, it will not break easily compared to paper impregnated with only melamine and acrylic emulsion. The paper quality is less likely to become brittle, making it extremely convenient to handle. Since the inside of the paper is impregnated with melamine resin and acrylic resin, it has sufficient paper strength and surface performance equivalent to ordinary finishing oil. (Example) Using an air knife coater, the composition shown in Table 1 was applied to titanium paper (size degree: 2 seconds) with a basis weight of 80 g/m ² , and the resin solid content was 80 g/m ² from the back side of the paper. It was coated and impregnated so that

[Table] For comparison, the same paper was coated with the composition shown in Table 2 using an air knife coater so that the resin solid content was 80 g/m ² from the back side.

[Table] The two types of reinforced paper obtained as described above are
24 hours after application and impregnation, 15g/m ² (solid content) of acrylic urethane resin was applied to each surface.
Various tests as shown in Table 3 were conducted.

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【table】

Claims (1)

[Claims] 1. In a method of manufacturing reinforced paper by impregnating decorative base paper or decorative paper with good permeability with a mixture of acrylic resin emulsion and melamine resin, a polyvinyl acetate resin with an average particle size of 20μ or more is added to the resin mixture. The solid content of the emulsion is 100%.
A method for producing reinforced paper, which comprises applying and impregnating a composition containing 10 to 50 parts by weight of a solid content per part by weight from the back side of decorative base paper or decorative paper.