JPH0438585B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a decorative laminate having wear resistance and high electrical conductivity.

[Conventional technology]

In general, thermosetting resin decorative boards have excellent properties such as heat resistance, abrasion resistance, stain resistance, and impact resistance, and have been used for office desks, work tables, and the like.

In particular, wear resistance is an important property of decorative laminates.
Conventionally, as shown in the cross-sectional view of Fig. 1, an abrasion resistance imparting agent mainly composed of silicon oxide and a reinforcing filler such as α-cellulose fine powder are applied to the upper surface of the patterned paper layer of a decorative board. Some synthetic resin layers are formed by mixing (Japanese Patent Publication No. 45-33297,
(See Special Publication No. 47-30635). However, in the pressurizing process, the wear-resistant synthetic resin layer B is located on the top layer of the decorative board and comes into direct contact with the surface of the metal forming plate, such as a mirror stainless steel plate, which is the pressurizing tool. However, due to its long-term and repeated use, the surface of the metal forming plate is worn out or has minute scratches.

In addition, due to uneven impregnation and application of the resin solution mixed with the wear resistance imparting agent, the wear resistance imparting agent may become unevenly distributed, and furthermore, there are disadvantages such as coloration due to silicon oxide, translucent areas, uneven gloss, etc. It was hot.

On the other hand, other wear-resistant decorative laminates (U.S. Patent No.
4255480, JP-A-55-67459) is the second
As shown in the figure, a wear-resistant thin film layer (a) containing aluminum oxide is coated on the surface of the patterned paper layer (4) via an organic binder layer (c).

However, in this decorative board, as in FIG. may cause minor scratches. In addition, since a wear-resistant thin film layer is formed on the surface of the patterned paper, when impregnated or coated with a synthetic resin solution, it is difficult for the resin solution to penetrate into the patterned paper layer. There are disadvantages such as formation of layers.

Furthermore, other wear-resistant decorative boards are shown in Figure 3.
A surface resin layer 2 made of a decorative overlay sheet of melamine resin is formed on the surface of a patterned paper layer 4 made of mixed paper mixed with an abrasion resistance imparting agent of aluminum oxide.

However, although this decorative board is not as noticeable as the decorative board shown in FIGS. 1 and 2 above, it may have the same drawbacks as described above depending on the resin flow of the surface resin layer during the pressure and heating process. Also, uneven formation of the pattern layer 2 (pattern printing unevenness) may occur due to printing, and the cost increases.

As mentioned above, abrasion-resistant decorative laminates have been proposed in the past, but these days, in addition to the abrasion resistance, these decorative laminates are designed to be used for computers, etc.
With the remarkable spread of electronic devices, there is a social demand for providing electrical conductivity to prevent static electricity problems when the devices are placed on the device. That is, since the thermosetting resin decorative board is insulating, it is easily charged with electricity and there is a high risk of the above-mentioned trouble occurring, and a decorative board that eliminates this problem is desired. Regarding such conductivity, conventional decorative boards include those in which a metal foil such as copper foil or aluminum foil is laminated on the surface layer. However, during drilling and other installation processes, the metal foil tends to peel or peel off from the processed parts, and the plate is also prone to warping, twisting, and other deformations, and on the other hand, it has the disadvantages of being relatively expensive. .

In addition, as other decorative laminates that have been given conductivity, there is also one that uses conductive paper on the surface of the laminate, which is made by mixing 20% or less carbon fiber with natural pulp fibers (Utility Model Application No. 58-38438). (see official bulletin).

However, when making the conductive paper, organic natural pulp fibers and inorganic carbon fibers are not compatible with each other, and from the viewpoint of manufacturing costs, single-sided conductive paper with carbon fibers arranged on the surface layer of one side of the natural pulp fiber base paper is difficult to compatibility with. Moreover, the base paper tends to be impregnated with thermosetting resin or coated unevenly, and since one side is the surface, the appearance such as color tone and design is not necessarily in a desirable state. It also had the disadvantage of being a relatively expensive decorative board.

[Problem that the invention seeks to solve]

The purpose of the present invention is to improve the various drawbacks of conventional wear-resistant decorative laminates, and to create a decorative laminate that has excellent abrasion resistance and does not cause grinding scratches on the surface of the metal forming plate during the pressurization process during manufacturing. It is about providing.

Another object of the present invention is to improve the various drawbacks of conventional conductive decorative laminates, to be effective in preventing the generation of static electricity, to have excellent conductivity, and to prevent the metal foil from turning over during processing and the decorative laminate during storage. An object of the present invention is to provide a conductive decorative board that does not cause warping or the like.

Furthermore, another object of the present invention is to provide a conductive decorative board with excellent wear resistance and a plain pattern on the surface of the decorative board.

[Means and examples for solving the problem]

The present invention is based on the fact that titanium oxide is originally incorporated into plain pattern base paper for decorative laminates in order to provide shading properties, and that titanium oxide is white or light-colored and is made electrically conductive by doping with silver, tin, etc. However, the use of various mineral substances and conductive substances that can provide conventional abrasion resistance may impair the design of the decorative laminate surface, especially the transparency of expensive resins. In view of this, the present invention was completed based on the new finding that it is most advantageous to selectively use titanium oxide, which has electrical conductivity, and aluminum oxide, which has wear resistance.

That is, the present invention provides a decorative laminate including at least one base material layer 6 and a plain patterned base paper 4 for decorative laminates laminated thereon, wherein the surface of the plain patterned base paper 4 for decorative laminates is coated with aluminum oxide. It has a thin film layer 2 of a certain thickness containing at least titanium oxide, and on top of the thin film layer 2, it further has a thin film layer 1 of a certain thickness mainly composed of a thermoset melamine resin. The above object is achieved by a wear-resistant conductive decorative board characterized in that the thin film layer 1 is formed as the outermost layer of the decorative board.

Examples and embodiments of the present invention
This will be explained based on FIG.

The thin film layer 2 formed on the surface of the plain pattern base paper 4 for decorative laminates that is commonly used is located below the surface protective layer to be described later, and forms an intermediate protective layer. Aluminum oxide and conductive titanium oxide are in the form of fine powder,
Uniformly dispersed and maintained.

The intermediate protective layer 2 is formed by applying a coating agent consisting of a mixture of the aluminum oxide and titanium oxide, and a printing ink binder containing pigments and/or dyes as necessary, to a certain thickness using a conventional method. It is formed by impregnating or coating plain pattern base paper 4 for decorative boards.

In this case, the average particle size of the aluminum oxide is 20~
It is preferably 40 μm and contained in an amount of 0.5 to 10% by weight based on the solid content of the coating agent. If the diameter is 20 μm or less, a relatively large amount of aluminum oxide must be mixed into the coating agent in order to achieve wear resistance of 300 times or more according to the JIS-K-6902 tapered abrasion test, resulting in economical and cosmetic problems. This is because it is disadvantageous in terms of the occurrence of cracks on the plate surface. Furthermore, the mineral is
It has low conductivity and is not preferred in terms of providing conductivity. On the other hand, if it is 40 μm or more, the amount of aluminum oxide mixed in will be small, but when the melamine resin is thermally cured, which will be described later, the aluminum oxide particles will break through the outermost melamine hardened layer and be exposed. This will damage the surface of 3 and cause wear and tear.

The solid content refers to resin solid content such as the binder of printing ink, that is, the resin composition after removing the solvent by scattering, and inorganic composition such as additives such as aluminum oxide, titanium oxide, and pigments. Refers to the total amount of things.

On the other hand, the average particle size of the titanium oxide is 0.5 to 10 μm.
It is preferable that the content is 30 to 80% by weight based on the total amount of the coating agent. This is because it is optimal for uniform dispersion in a coating agent, and also produces a surface conductivity, that is, a surface electrical resistance, in a preferable range of 10 ⁵ to 10 ⁸ ohms after forming a decorative board, which will be described later.

Further, it is more preferable to dope the surface of the titanium oxide particles with silver, tin, aluminum, etc., which have excellent conductivity and are white or light-colored. Further, if the particles are secondary agglomerated, it is more advantageous for uniform dispersion in the coating agent and improved conductivity.

The pigment or dye added as necessary is
A hue adjusting agent and/or conditioner having a color similar to that of the decorative board pattern base paper, and containing at least one of yellow lead, zinc sulfide, and other inorganic and/or organic materials in an amount of 0.1 to 40% by weight based on the total amount of the coating agent. Advantageously, it is contained. In addition to increasing the color tone of the plain pattern base paper, it is possible to create complex colors that cannot be obtained by solid printing alone on the plain pattern base paper, and fine powder of titanium oxide is mixed in the coating agent. concealment is enhanced,
This is because the stability of color tone is significantly improved.

The decorative paper printing ink binder has an extremely high affinity with the plain pattern base paper, and is coated with each of the substances described above. The main component is at least one of oil-soluble or water-soluble methylcellulose, ethylcellulose, nitrocellulose, and cellulose acetate, and is contained in an amount of 15 to 30% by weight in terms of solid content based on the total amount of the coating agent. It is advantageous to have

The coating agent made of the above-mentioned substances is coated on the surface of the plain pattern base paper 4 to a thickness of 15 to 45 μm so as to obtain suitable conductivity and abrasion resistance.

Coating methods include dip methods such as impregnation and size press, coating methods such as gravure coating, air knife coating, and roll coating.
It is not limited to these.

It should be noted that the present invention mainly uses plain light-colored pattern base paper rather than paper having various patterns. The plain pattern base paper has a basis weight of 60~
140g/ ^m2 , and titanium oxide as a shadowing agent is incorporated in 0 to 40% by weight of the entire paper, and if necessary, pigments and/or dye coloring agents are incorporated in 0.1 to 10% by weight. This is advantageous in providing a beautiful surface finish.

Next, the thin film layer 1 formed on the intermediate protective layer 2 serves as a strong outermost protective layer, and is formed by applying a water-dispersed resin solution containing melamine resin as a main component to the coated plain pattern. The top surface of the paper is impregnated and coated using a conventional method.

The water-dispersed resin solution containing the melamine resin as a main component has a resin solid content of at least 30% of the total amount.
It is particularly preferable to use water or a mixed solution of water and alcohol containing 60% by weight and further containing a methylolmelamine formaldehyde condensate as a main component. The reason for this is that melamine resin has the best hardness and transparency among various thermosetting resins, and because it is a water-dispersed resin solution, it is mainly used as an oil-soluble printing ink binder that forms the intermediate protective layer 2. This is because it is not compatible with the coating as a component and is convenient for impregnating and coating the solution to form the top layer coating.

The melamine resin has a volatile component in its air-dried solid state, and the total weight of the plain pattern paper impregnated with the water-dispersed resin solution is
A content of 70 to 100% by weight in terms of air-dried solid content is advantageous in imparting wear resistance.

The thickness of the outermost layer is usually from several microns to several tens of microns.

Finally, the base material layer 6 located below the plain pattern base paper 4 for decorative laminates is made of thermosetting resin impregnated core paper, particle board, plywood, mesh board, thermoplastic resin impregnated core paper, etc. It is not limited.

The decorative board of the present invention is manufactured by using a conventional method to prepare a deposited body consisting of the plain pattern atoms 4 (hereinafter referred to as pre-regs) and the base material layer 6 covered with the intermediate protective layer 2 and the outermost protective layer 1. Then, heat and pressurize. The heating and pressing conditions vary depending on the type and amount of thermosetting resin used (impregnated or applied amount), but the heating temperature is approximately 120°C to 170°C, the heating time is approximately 5 minutes to 30 minutes, and the heating time is approximately 5 minutes to 30 minutes. The pressure is 20-80Kg/ ^cm2 .

[Effect]

The decorative board of the present invention is constructed as described above, and does not use a conventional overlay sheet, that is, a chemically engineered paper whose core paper is thin paper mainly composed of α-cellulose impregnated with melamine resin, and has a surface protective layer 1.
The surface protective layer 1 is mainly composed of melamine resin and does not contain aluminum oxide. Therefore, wear and tear on the forming plate during production of the decorative laminate of the present invention is prevented.

Furthermore, an intermediate protective layer 2 below the surface protective layer 1
Since aluminum oxide having a Mohs hardness of 7 or more and having a relatively large particle size is uniformly mixed, the hardness and strength of the surface protective layer are reinforced. Therefore, even without using an overlay sheet,
It produces a surface hardness equivalent to the abrasion resistance of the overlay sheet, that is, a practically necessary hardness of 300 times or more of abrasion by JIS-K-6902 taper type abrasion test.

On the other hand, the titanium oxide mixed into the intermediate protective layer 2 prevents and removes static electricity that is likely to occur on the surface of the plastic molded product. In addition, mixing in the form of fine powder will not cause the metal foil to turn over during decorative board processing.

Incidentally, when the intermediate protective layer 2 is formed, the electrical resistance value of the surface of the intermediate protective layer 2 at room temperature is 10 ³ to 10 ⁶ ohms depending on the amount of titanium oxide mixed. However, after the surface protective layer 1 is formed, the electrical resistance at the outermost surface of the decorative board is reduced by the thin film 1.
The value decreases to 10 ⁵ to 10 ³ ohms, which is a suitable value, that is, a suitable value and range necessary to completely eliminate the drawback of being easily charged due to its insulating properties.

The uniformly dispersed mixture of white or light-colored aluminum oxide and titanium oxide and the transparency of the melamine resin result in a beautiful finish on the plain surface of the decorative board.

〔Concrete example〕

A solution prepared by mixing 15 parts of conductive titanium oxide fine powder and 3 parts of aluminum oxide with 30 parts of a cellulose acetate-based printing medium solution containing about 40% solids was added to a printing paper for decorative boards. Amount 80g/ ^m2
Apply 27g/ ^m2 on the surface of the pattern base paper and let it dry.
The coated decorative paper having a surface electrical resistance value of 10 ³ to ^{10 5} ohms is impregnated with a melamine resin solution in a conventional manner, coated and dried, and the pre-printed paper is coated as the top layer of the decorative board. As shown in the figure, it was laminated on a base material layer and heated and pressurized to obtain a wear-resistant conductive decorative plate of the present invention. When the electrical resistance value of the surface of this decorative board was measured, it was 2.7×10 ⁵ ohms, and the abrasion resistance value of the tapered abraser was 560 times.

〔Effect of the invention〕

The advantages of the present invention are as follows.

It is possible to provide a wear-resistant conductive decorative board with excellent aesthetic appearance on the plain surface finish of the decorative board.

We can provide conductive decorative boards that have excellent radio wave shielding effects and antistatic effects for electrical equipment,
Further, during the processing of the decorative board, it is possible to provide a conductive decorative board that does not cause peeling of the metal foil or the like as a conductivity-imparting substance, and is free from warping or distortion of the board due to the properties of the metal foil.

Furthermore, such characteristics can improve the efficiency of manufacturing operations and reduce costs.

It is possible to provide a conductive decorative board that has excellent abrasion resistance and is less expensive without using an overlay sheet.

In addition, the decorative board does not cause polishing scratches on the surface of the mirror-finished metal molding board during its manufacture, allowing the manufacturing equipment to be used continuously for a long period of time.

[Brief explanation of drawings]

Figures 1 to 3 are cross-sectional views of conventional thermosetting resin decorative laminates, Figures 4 to 6 are schematic enlarged cross-sectional views of the surface protective layer of the decorative laminate of the present invention, and Figure 7 is the main FIG. 2 is a cross-sectional view of the configuration when hot-pressing the abrasion-resistant conductive decorative laminate of the invention. DESCRIPTION OF SYMBOLS 1... Surface protective layer, 2... Intermediate protective layer, 3... Metal forming template, 4... Plain pattern base paper, 5... Solid ink layer, 6... Base material.

Claims (1)

[Scope of Claims] 1 A decorative laminate comprising at least one base material layer 6 and a plain patterned base paper 4 for decorative laminates laminated thereon, wherein the surface of the plain patterned base paper 4 for decorative laminates is coated with aluminum oxide. and titanium oxide, and on top of the thin film layer 2 there is a thin film layer 1 mainly composed of a thermoset melamine resin, with the thin film layer 1 as the top layer. A wear-resistant conductive decorative board characterized by: