JPS6227196B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel interior material for buildings, and more particularly to a method for producing an interior material having excellent decorative properties and excellent conductivity. Traditionally, plastics, especially soft and hard vinyl chloride resin, have been widely used for interior materials for buildings such as wall coverings and floor coverings, but recently there has been a demand for interior materials suitable for computer rooms. The need for Interior materials for computer rooms are required to have electrical conductivity, in addition to general characteristics of conventional interior materials such as decorativeness, livability, water resistance, abrasion resistance, and stain resistance. This is to dissipate and eliminate minute amounts of static electricity generated from the computer itself, to prevent static electricity generated from these interior materials from being transmitted to the computer, and to prevent static electricity generated from the clothes and other objects of the operators operating the computers in the computer room. This has three purposes: to dissipate static electricity to the ground and dissipate it without transmitting it to the computer. However, since conventional interior materials were not developed for these purposes, they do not have these characteristics, that is, conductivity. In the case of wall covering materials, there are no materials with this characteristic, and only a few can be found in the field of flooring materials. This is used in the medical field to prevent anesthetic gas from igniting and causing an explosion due to sparks from the electric scalpel used during surgery or static electricity discharged from the clothing of doctors and nurses. ing. Conventionally, there are three types of conductive floors used for these purposes, but all of them have the drawbacks described below and are not satisfactory products, especially for computer rooms that require high comfort. Not suitable at all. That is, (1) metal joint rods are exposed on the floor surface and the gaps between the metal rods are filled with cement, etc. (2) conductive carbon black is kneaded into cement to finish the floor surface (3) conductive There is one in which carbon black is kneaded into soft PVC or rubber, processed into tiles, and then adhered to the concrete floor surface. However, in these conductive beds (1), only the metal bar part is conductive, and the other parts have no conductivity at all, so the probability of contact is small and the dissipation of static electricity is not smooth. Type (2) uses cement mixed with carbon black, so the color of the floor is limited to solid black or a color based on black, making it impossible to obtain a color suitable for an operating room. Item (3) can be said to cover the drawbacks of items (1) and (2), but since black is the basic color, it has the same drawbacks as item (2), and it also has 30× 30cm or 25×25
Since it is in the form of tiles with dimensions of cm, it is necessary to ground between each tile when pasting them, which is extremely troublesome. Recently, aluminum tile-shaped floor coverings have been commercially available for use in computer rooms, but these also have the same drawbacks as in (3) above and are extremely expensive. The present invention aims to eliminate such drawbacks and deficiencies and provide a wide and long sheet-like interior material that is beautiful and has excellent conductivity.An example of its implementation will be described with reference to the drawings. Conductive thermoplastic synthetic resin particles with a two-layer structure consisting of a black layer containing black powder and a conventional optionally colored layer are spread on a release strip to a predetermined thickness, and then rolled under heat with a press roll. A conductive interior material characterized by compressing the densified sheet between layers, then peeling off the release band, and using the densified sheet as a surface layer and laminating a highly conductive backing material on the back side of the surface layer. , wherein the conductive thermoplastic synthetic resin particles A have a two-layer structure of layer a and layer b;
is a black layer containing conductive carbon black powder, and is made of a thermoplastic synthetic resin composition having a lower softening and melting temperature than layer b; layer b is white, red, green,
This layer is a non-conductive colored layer that has been given any color suitable for an interior material, such as yellow, blue, or brown, and is made of a thermoplastic synthetic resin composition that has a higher softening and melting temperature than the black layer a. The amount of conductive carbon mixed in the black layer a varies depending on the type of carbon used and the diameter of the carbon powder, but the key is to keep the volume resistivity of the black layer a itself to about 10 ⁵ to ^{10 2} Ω・cm. Usually, the amount of carbon mixed in is 10% by weight or more of the blended composition. The particle size of the conductive thermoplastic synthetic resin particles A is determined by the purpose of the interior material, such as whether it will be used as a wall covering material, a floor covering material, or as a table top for an antistatic workbench. ,
Generally speaking, if the thickness is in the range of 0.5 to 5.0 mm, a conductive interior material having antistatic properties with a thickness of 0.4 to 2.5 mm can be obtained as a product. The thickness of the black layer a and the colored layer b is the internal division ratio of the thickness of the particle A itself.
In the case of 1.0 mm, the black layer a is 0.1 to 0.5 mm, and the colored layer b is
A range of 0.9 to 0.5 mm, ie a layer a: layer b thickness ratio of 1:9 to 1:1, is suitable. black layer a
If the thickness exceeds 1:1, the overall appearance after becoming a product will be close to black, and will be the same as or close to the conventional product 3 above,
Undesirable for use. Moreover, if the thickness of the black layer a is less than 1:9, it is advantageous in terms of decoration because it can brighten the color, but it is disadvantageous in terms of conductivity because it becomes unstable. The conductive thermoplastic synthetic resin particles A may be monochromatic or multicolored. Monochromatic means that when the colored layer B is brown, the surface layer B is composed only of particles with a black-brown two-layer structure, and polychromatic means that the colored layer B consists of brown, red, green, and white particles. Particles such as brown-black, red-black, green-black, and white-black conductive particles are prepared in advance, and before use, a mixture of appropriate amounts of these particles is applied to the surface. Layer B
means that it consists of. These combinations should be determined by the use of the interior material and color design. The thickness of the black layer a and the thickness of the colored layer b are as described above.
By laminating the layers, it is sufficient that the surface layer B has conductivity in the thickness direction, and therefore the layer a also has a ratio of 1:9 to 1:9.
Excellent conductivity can be obtained with a relatively thin combination of 2:8, and as a result, a light-colored interior material in which the presence of the black layer a is not so noticeable can be obtained. Furthermore, in this case, non-conductive colored thermoplastic synthetic resin particles A' can also be mixed with the two-layered conductive particles A. When the mixing ratio of conductive particles A containing 30% carbon black powder and the thickness ratio of black layer a to colored layer b is 2:8 and non-conductive colored particles A' is 1:1, the surface Layer B alone has no conductivity in the surface direction, but when layer B is laminated with backing material C, which has good conductivity,
A volume resistivity value of 10 ⁴ Ω・cm can be obtained.
This completely overturns the conventional idea that "conductive interior material is black interior material", and rather effectively utilizes the existence of black layer a made of carbon black as a pattern. I can do it.
As a result, the resulting interior material is light-colored and has a granite-like appearance, and can be used not only for floor coverings, but also for wall coverings in precision parts assembly factories and electronics-related factories where static electricity generation and charging are disliked. It can be used as a workbench top. The thermoplastic synthetic resins used in the production method of the present invention include polyvinyl chloride resin and vinyl chloride copolymer, ethylene-vinyl acetate copolymer, chlorinated polyethylene, terpolymer resin such as ABS and MBS, NBR It is not particularly limited and may be any commonly used soft thermoplastic synthetic resin such as thermoplastic synthetic rubber, or may be a polymer blend system in which these are mixed together. In addition, plasticizers, stabilizers, fillers, antioxidants, binders, etc., which are generally called "compounding agents" or "additives", may be added or blended into these thermoplastic synthetic resins as necessary. This can be done arbitrarily and is not particularly limited. When the same thermoplastic synthetic resin is used for the black layer a and the colored layer b, the softening and melting temperature can be made lower than that of the layer b by adding a large amount of plasticizer to the layer a. , In the case of the same type of resin, in the case of resin with a different degree of polymerization, for example, polyvinyl chloride resin, layer a has a degree of polymerization of 800.
By using a material with a degree of polymerization of about 2000 as layer b and further changing the amount of plasticizer, it is possible to create formulations with considerably different softening and melting temperatures.
The most effective method is to use a vinyl chloride-vinyl acetate copolymer, which can produce a difference of 10 to 15°C in softening and melting temperature when the degree of polymerization is the same and the amount of plasticizer added is the same. This is extremely important in the present invention, and the synthetic resin particles A are spread in a layered manner with a predetermined thickness on a release zone, and under heating, a metal roll consisting of a metal roll and a back-up rubber roll is spread. is heated to a required temperature, and then compressed and densified through pressure rolls such as a clearance embosser in which the gap between a metal roll and a back-up rubber roll is adjusted to a predetermined gap. If the softening and melting temperature of either of them is not low, sufficient densification will not be achieved and only a sheet with many voids will be obtained. However, layer a or layer b
If one of the layers has a low softening and melting temperature, when a pressing force is applied through the press rolls, the layer with the lower softening and melting temperature deforms and flows between the particles, filling the voids and forming a dense surface layer B. On the other hand, a layer with a high softening and melting temperature is less likely to deform even when a pressing force is applied, and retains its particle shape, thereby producing a pattern effect. In the case of the present invention, the black layer a containing carbon black powder has a lower softening and melting temperature than the colored layer b, and is thinner than the colored layer b, so that the interior color can be brightened. The result is that the material is obtained. The release band used in the present invention is a release band that is rigid and does not soften even under heated conditions, such as release paper or a release cloth made of dense, thin fabric such as Tricotto and silicone resin baked onto it. Conductive synthetic resin particles are dispersed and spread in a layer to a predetermined thickness on the release strip, heated, and then compressed between press rolls. Direct pressure is applied to the softened and melted particles, making it extremely difficult to use. An excellent compression effect is obtained, resulting in a very good densified sheet. Instead of using such a release band, for example, a conductive thermoplastic synthetic resin sheet to which conductive carbon black powder has been added is used as the backing material, and conductive synthetic resin particles are scattered and spread on the upper surface of the sheet, and the same method is used. When heated and compressed, the backing material also softens and melts, causing a phenomenon of "embedding" of the softened particles, and the compressive force does not work effectively, resulting in insufficient densification. In the case of conductive interior materials, this densification is very important for developing conductivity and providing stable conductivity, and can be said to be very excellent in the present invention. The highly conductive backing material C that is laminated on the surface layer B is made by adding metal foil or conductive carbon black powder to a thermoplastic synthetic resin. Either side of B may be used, but it is optimal that the surface in contact with the metal roll of the pressure roll is the front surface, the surface that was in contact with the release band is the back surface, and the backing material C is laminated on this back surface. .
This is because although the surface of surface layer B in contact with the release zone, that is, the surface on the back-up rubber roll side, has excellent smoothness, it is somewhat insufficient in terms of densification compared to the surface in contact with the metal roll. Occasionally pinholes may be observed. This is due to the fact that during heating and softening in the heating furnace, the way the heat is applied is somewhat inhibited by the release zone, the pressing force is lost due to the elasticity of the back-up rubber roll, and the cooling effect of the back-up rubber roll. It is thought that the compression effect becomes insufficient due to this. In this point, the pressing force of the metal roll acts directly on the particle surface that is in contact with the metal roll, especially the heated metal roll, and the heated and softened particles are not cooled at that time, so that the densification due to the pressing force is not sufficient. This is because the sheet is made dense. When laminating this backing material C, it is also possible to laminate it on the side of the surface layer that was in contact with the metal roll. Lamination may also be carried out by calendar topping, extrusion lamination, coating method, etc., without departing from the scope of the present invention. Furthermore, when the interior material obtained according to the present invention is applied to a floor, wall, or workbench, the backing fabric D is often attached to the interior material in order to improve the adhesion between the underlying surface and the interior material. In this case, coarse cheesecloth or mosquito-covering material is suitable as the backing fabric. In the present invention, in addition to the conductive particles A having a two-layer structure, non-conductive colored thermoplastic synthetic resin particles A' can be mixed and used. In this case, the colored particles A' also have a two-layer structure, and either one of them By using a thermoplastic synthetic resin composition with a low softening and melting temperature, the entire surface layer B can be made into a densified sheet without voids. The combination of two-layer structures in the colored particles may be the same color or the same color system with shading, or a combination of different colors. Of course, in this case, by preparing several types of colored particles of different colors, weighing them appropriately before use, and mixing them with conductive particles A, it is possible to create an interior material with a better sense of color. You can. Of course, the non-conductive particles A' may also have a single layer structure. Furthermore, the surface layer B is a semi-conductive layer that exhibits no conductivity or no effective conductivity by itself, but exhibits excellent conductivity by laminating a highly conductive backing material C. It may be hot. Next, specific embodiments of the present invention will be explained using examples. Example 1 (1) Production of conductive thermoplastic synthetic resin particles A. 10% carbon black powder by the following formulation 1
Make a mixed sheet with a thickness of 0.2 mm.

[Table] Next, according to formulation 2, a sheet with a thickness of 1.8 mm was obtained.

[Table] The sheet obtained by Formulation 1 and the sheet obtained by Formulation 2 were laminated to a thickness of 2.0 mm, and then subjected to a crusher to obtain conductive particles A having an average particle diameter of 2.5 mm. The thickness ratio of layer a to layer b of this particle A is 1:9
It is. (2) Production of densified sheet B Next, the conductive particles were coated with release paper (thickness = 0.3
mm) to a thickness of 4.5 mm, heated in a heating furnace at 150°C, introduced between clearance embossers adjusted to a clearance of 2.8 mm in advance, pressed, compressed and densified, cooled, and released. Peel off the pattern to make it 2.5 thick.
A light brown sheet B having a granite-like appearance of 3 mm was obtained. This sheet B could be used alone as an interior material, and its conductivity was as follows. Insulation resistance value 5×10 ⁵ Ω or less ^*1 Charge voltage 160V ^*2 *1 Based on the Foil Test method of NFPA test method Distance between electrodes 90cm Metal foil used Aluminum electrode 5 ^16S , 2 1/2 inch diameter measuring instrument Insulation resistance Meter (Megger) Rated voltage 500V Short circuit current 2.5 to 10 milliampere *2 Rubbed 50 times with nylon stockings using a current collector potential measuring device ( ^Kasuga Denki) This fully satisfies the value of 10 ³ to 10 ⁸ Ω required for machine rooms, and a sheet with such performance and a beautiful light brown color has never been available before, making it ideal for use on computer room floors. It was suitable as a floor covering and wall covering material. Example 2 An interior material was manufactured in the same manner as in Example 1, except that a sheet of Formulation 3 with a carbon black content of 30% was used in place of the sheet of Formulation 1 of Example (1).

[Table] The appearance of the interior material obtained in this way is Example 1
However, the conductivity was several orders of magnitude better than that of Example 1. Insulation resistance value 3.2×10 ⁴ Ω Charge voltage 60V Example 3 A highly conductive backing material C with a carbon black content of 18% according to formulation 4 was placed on the back side of the sheet B obtained in Example 1.
were laminated.

[Table] The conductivity of the interior material of this laminated backing material was as follows. Insulation resistance value 2.6×10 ⁴ Ω Charge voltage 0 Example 4 On the back side of the sheet obtained in Example 2, a backing material C similar to that in Example 3 was laminated. The conductivity of the interior material of this laminated backing material was as follows. Insulation resistance value 1.2×10 ⁴ Ω Charge voltage 0 Examples 5 to 9 The conductive particles A used in Example 2 and the two-layer structure non-conductive colored particles A′ according to the following formulations 5 and 6 were mixed as shown below. By mixing in the same proportions, an interior material for laminated backing material was obtained in the same manner as in Example 4.

【table】

[Table] Make it a child.

[Table] These interior materials are a mixture of light brown and light green, and are beautiful and the presence of black does not bother you at all, making them suitable for use in hospital operating rooms.

[Brief explanation of the drawing]

The drawings show examples of the conductive interior material manufactured according to the present invention, in which Fig. 1 is a cross-sectional view of conductive thermoplastic synthetic resin particles, and Fig. 2 is a cross-sectional view of the surface layer made of a densified sheet. 3 and 3 are cross-sectional views of the interior material, and FIG. 4 is a cross-sectional view of another embodiment.
A is a conductive particle, A' is a non-conductive particle, B is a surface layer made of a densified sheet, a is a black layer, and b is a colored layer.

Claims (1)

[Claims] 1 Synthetic resin particles have a two-layer structure of a conductive black layer containing conductive carbon black powder and a non-conductive colored layer that is customarily colored, and the softening melting temperature of the black layer is higher than that of the colored layer. The particles are conductive thermoplastic synthetic resin particles whose temperature is lower than the temperature, and the particles are spread alone or in a mixed state with non-conductive colored synthetic resin particles in a layer of a predetermined thickness on the upper surface of the release strip, and then heated. The particles were heated and softened in a furnace, then introduced between pressure rolls adjusted to a predetermined gap to press and compress the particle layer, and then the release band was peeled off to form a densified sheet. After that, the densified sheet is used as a surface layer, and a backing material made of a highly conductive thermoplastic synthetic resin sheet to which metal foil or conductive carbon black powder is added is laminated. Method.