JPS6115819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endless type decorative sheet that is flexible and has a surface performance equivalent to that of a thermosetting resin decorative sheet. Conventionally, thermosetting resin decorative laminates have been produced using a so-called press method, in which decorative paper and core base paper are impregnated with thermosetting resin, laminated and laminated at high temperature and pressure.
Alternatively, a method is known in which a necessary number of endless sheets of thermosetting resin-impregnated paper are stacked on top of each other and manufactured by a continuous lamination method. Therefore, in the conventional method, high temperature and high pressure are necessary conditions for laminating and molding paper impregnated with thermosetting resin. Further, such decorative boards have drawbacks such as being difficult to bend and making it difficult to obtain thin decorative boards. The present invention has been made in consideration of this point, and relates to a decorative sheet in which a flexible decorative layer and a resin-impregnated reinforced core layer are bonded together with an adhesive. Normally, in order to make a decorative sheet for the desired purpose using a decorative board, it is desirable to impregnate the inside with a resin to increase the strength within the layers of the base paper. In this case, it is well known that impregnation with a thermoplastic dispersion improves the reinforcing effect and flexibility, but it is difficult to disperse the plastic particles into the cellulose by just impregnating with a thermoplastic dispersion, or the plastic particles disappear during drying. Due to the lack of reinforcing effect inside the decorative paper, a defect occurs in that the center layer is easily torn. The thermoplastic dispersion can be completely penetrated into the interior of the decorative board by applying a cationic active liquid to the base paper in advance, or by pre-impregnating it with a polycationic compound, then immersing it in an anionic synthetic resin liquid and drying it. It is known that penetration is achieved satisfactorily. In the present invention, decorative paper is coated with a thermoplastic dispersion from one side (preferably the back side) and then dried. In this case, as described above, the plastic particles are not completely dispersed in all layers of the decorative paper, and the desired performance value cannot be obtained in terms of the strength within the layers of the cardboard. By coating and impregnating a thermosetting resin on one side (preferably the back side) of the decorative paper obtained in this way and drying it, primary reinforcement can sufficiently improve the intralayer strength of the decorative paper and at the same time meet the required performance as a decorative sheet. This can be obtained by ensuring that Regarding the core layer, it is desirable to give the aforementioned thermoplastic dispersion a sizing effect and to add a small amount of amino resin to the thermosetting resin in order to increase the impregnation and dispersion effect, and further to use an anionic active wetting agent. . A core base paper such as kraft paper is impregnated with the thermoplastic dispersion and dried to obtain a desired core. In this case, a porous core base paper with long fibers is selected to have a different impregnating and dispersing property than the above-mentioned high-density decorative paper. Thereafter, a decorative sheet is obtained by adhering and integrating the decorative layer and the core layer by a dry lamination method using a thermoplastic resin. The decorative sheet thus obtained has a surface performance equivalent to that of a thermosetting resin decorative board and is highly flexible, so it retains the ability to be processed into curved surfaces. Note that a sheet with a pressure-sensitive adhesive attached to the back side is also highly flexible and suitable for processing curved surfaces. Next, the present invention will be specifically explained as follows. The resin to be coated and impregnated from one side (preferably the back side) of the decorative paper for reinforcement is a thermoplastic dispersion of polyacrylate, polyvinyl acetate, polyvinyl chloride, or polymethacrylate, or an acrylate ester group, a methacrylate ester group, or methyl. Reticulated synthetic resin dispersion based on methacrylamide alone, SBR, NBR
It is a resin dispersion liquid such as. When these resin dispersions alone require impregnating properties, the impregnating effect can be achieved by using a resin dispersion to which an anionically active wetting agent is added. The resin dispersion is coated and impregnated from one side (preferably the back side) of the decorative paper using a coating dryer, and then heated and dried at 100 to 180°C to volatilize the water and simultaneously crosslink the thermoplastic resin. Improves the inner strength of advanced decorative paper. The intralayer strength of the base paper with only this primary impregnation can only ensure a plane tensile strength of 3 to 5 kg/cm ² . On the other hand, as the resin for impregnating the coating on the surface layer side, a thermosetting resin such as a fast-curing type melamine resin, amino alkyd resin, unsaturated polyester resin, diallyl phthalate resin, etc. is used. The curing agent, curing accelerator, etc. may be selected according to the type of resin, heat drying conditions, pot life of the resin, etc. As for the erasing agent, for example, an inorganic powder containing silicon oxide may be selected that is suitable for the manufacturing conditions. The thermosetting resin is coated on the surface layer side of the decorative paper and at the same time impregnated inside. Thereafter, curing is accelerated by heating and drying at 110 to 180°C. The intralayer strength of the thus obtained decorative sheet increases to 8 Kg/cm ² to 15 Kg/cm ² in plane tensile strength. Next, the resins used for reinforcing the core layer include a reticulated synthetic resin dispersion based on acrylic ester groups, methacrylic ester groups, and methyl methacrylamide alone;
In order to improve the sizing effect and the impregnating and dispersing properties of plastic particles, a small amount of methylolated melamine is added to resin dispersions such as SBR and NBR, and an anionic active wetting agent is also used. The thermoplastic dispersion is impregnated into core paper using a coating dryer, and then
By heating and drying at ℃, water is volatilized and at the same time crosslinking of the resin is promoted and the interlayer strength of the core paper is improved. The in-layer strength of the core paper increases to 8Kg/cm ² to 12Kg/cm ² in plane tensile strength. The above-mentioned decorative sheet is obtained using the core layer thus obtained.
Acrylic pressure sensitive type, EVA on the back side of the sheet
Select a hotmel type, rubber type, etc. that is suitable for the purpose of use. Next, a typical example will be described. Example 1 Aqueous dispersion of modified acrylic acid ester copolymer with excellent self-crosslinking properties, solid content 30%, viscosity 50 cp,
A resin for primary impregnation was prepared by adding 0.2 parts of an anionically active wetting agent to particles having an average particle size of 0.1 to 0.3μ. The basis weight is
The resin is coated and impregnated from the back side of 55 g/m ² of decorative base paper and controlled using a round rod so that the amount is 20 to 25% by weight. Thereafter, it was heated and dried for 5 minutes in a dryer at 160°C to prepare a primary impregnated sheet. Next, use plastic type melamine resin with a solid content of 45
%, viscosity 55cp is coated from the surface side of the primary impregnated sheet to give a coating of 10 to 15% on the primary impregnated sheet.
Control with a round bar to maintain the weight%.
Thereafter, it was heated and dried at 150°C for 10 minutes to create a decorative sheet. Next, solids are removed using styrene-butadiene latex.
45%, viscosity 100cp, average particle size 0.1-0.15, 20 parts methylolated melamine, 0.2 parts anionic active wetting agent.
180 g/m ² of base paper for core is impregnated with the added material and dried by heating. The amount of adhesion is controlled at 35-40% by weight. This core paper and the aforementioned decorative sheet were dry laminated with polyethylene resin to obtain an endless decorative sheet. This decorative sheet shows the performance as shown in the attached table. Example 2 A resin for primary impregnation was prepared by adding 0.2 parts of an anionic wetting agent to SBR having a solid content of 50% and a viscosity of 60 cp. Coat and impregnate the resin from the back side of decorative paper with a basis weight of 55 g/m ² and control it with a round bar so that it becomes 25 to 30% by weight. Then, heat dry it for 5 minutes in a dryer at 140 ° C. , a primary impregnated sheet was created. Next, with amino alkyd resin, the solid content is 40%.
%, viscosity 60 cp from the surface side of the primary impregnated sheet.
Control it with a round bar so that it is 20% by weight. Thereafter, a decorative sheet was prepared by heating and drying at 130°C for 5 minutes. Next, we use a modified acrylic ester copolymer with a self-crosslinking solid content of 30% and a viscosity of 30%.
It is impregnated into 180 g/m ² of base paper for a core prepared by adding 0.2 parts of an anionic wetting agent to 50 cp and an average particle size of 0.1 to 0.3 μ and dried by heating. The amount of adhesion is controlled at 35-40% by weight. This core paper was integrated with the aforementioned decorative sheet by a wet method to obtain an endless decorative sheet. An acrylic pressure-sensitive type adhesive with a film thickness of 80 to 100 μm was applied to the back side of the sheet to obtain a sheet with separate paper. The performance of the decorative sheet used here is shown in the attached table. 【table】

Claims (1)

[Claims] 1. A decorative surface sheet obtained by coating or impregnating a decorative paper with a thermoplastic resin dispersion liquid on one side and a fast-curing type thermosetting resin on the other side, and then curing with heat. This endless type decorative sheet is made by applying or impregnating a thermoplastic resin dispersion containing a small amount of a thermosetting resin into a kraft liquid and pasting it onto a core paper obtained by heating and curing. 2 A decorative surface sheet obtained by coating or impregnating decorative paper with a thermoplastic resin dispersion on one side and a fast-curing type thermosetting resin on the other side, and then heating and curing the paper, An endless type decorative sheet that is attached to a core paper obtained by coating or impregnating kraft paper with a thermoplastic resin dispersion containing a plastic resin and curing it by heating, and has an adhesive and release paper on the back side.