JPH045314Y2 - - Google Patents

Description

[Detailed explanation of the idea]

B. Purpose of the invention Industrial application field The present invention relates to a cushioning material used when hot press molding or simple press molding of decorative boards, resin boards such as PVC boards, various resin laminates, plywood, etc. Prior Art Conventionally, asbestos millboard has been used as a cushioning material for presses, but it has been replaced by rubber cushioning materials due to hygiene problems. However, this rubber cushioning material is easily deteriorated by heat and has poor durability, so there is a desire for a product to be developed to replace it. In recent years, as a product developed in this field, for example,
Publication No. 7646, Publication of Utility Model Publication No. 1983-7648, Japanese Patent Application Publication No. 1983-
Cushioning materials such as those disclosed in Publication No. 192795 have been proposed. The product disclosed in Japanese Utility Model Application Publication No. 58-7646 is a heat-resistant nonwoven fabric impregnated with a resin, etc., and the same nonwoven fabric is laminated on the surface. A release layer made of fluororesin is formed on the surface of the mold. However, although these have good heat resistance, their durability is still unsatisfactory. Furthermore, the material disclosed in JP-A-59-192795 is a cushioning material made of fine inorganic fibers and pulp-like particles of an aromatic polymer, and although it has improved durability, it does not have antistatic properties. In addition, since it has poor thermal conductivity, it has major drawbacks in terms of workability, thermal efficiency, and productivity. Problems that the invention aims to solve In view of the current situation as described above, the inventors of this invention
Patent application (Japanese Patent Application No. 60-177436, Japanese Patent Application Publication No. 177436,
62-37102) Invention "Cushioning material for press"
In this paper, a felt-like material was provided as a novel and extremely useful cushioning material that has antistatic properties and improved thermal conductivity. The present invention can be said to be an improved or applied product of the invention of the previous application, ``Cushioning material for press'' (hereinafter simply referred to as ``the invention''). That is, the invention is different from conventional cushioning materials,
It prevents the generation of static electricity, eliminates static shock for workers, prevents the generation of defective products due to adsorption of impurities, and improves thermal conductivity to improve performance and productivity, and can be used as is. Of course, this is a good thing, but since this product contains inorganic fibers, the inorganic fibers that fall off may cause discomfort to the operator, or they may adhere to the object to be pressed, resulting in defective products. It happens that something like this occurs. The present invention has been made to solve this problem, and is made by laminating woven fabric or non-woven fabric on both or one side of the felt-like product of the above-mentioned invention. By the way, there have been cushioning materials for presses in which non-woven fabrics, etc. are laminated on both or one side of the cushioning material, but these are used for purposes such as maintaining cushioning properties, preventing adhesion to hot press plates and mirror plates, and improving strength. The purpose of this invention is completely different from that of the present invention, which is to prevent fibers from falling off, and the surface layer of the present invention is not simply a woven or nonwoven fabric, but is also designed to remove static electricity and improve thermal conductivity. However, the characteristics of the felt-like material of the invention are not impaired in any way. In addition, since the present invention is also a laminated structure, it goes without saying that it also exhibits effects such as improved strength. B. Structure and operation of the invention The structure of the invention is such that a felt material made of organic fibers, a conductive filler, inorganic fibers, and a binder is coated with a fabric made of conductive fibers and organic fibers on both sides or one side of the felt material. The gist is a cushioning material for presses characterized by a laminated layer of cloth or non-woven fabric, and the most suitable material for this conductive filler or conductive fibrous material is selected from carbon, graphite, and metal. It has become a thing. First, since the felt-like material in the present invention is similar to the above-mentioned invention, the felt-like material in the invention, that is, the present invention, will be briefly explained. In other words, this felt-like material is made by blending a conductive filler and a binder into a press cushioning material containing organic fibers, particularly heat-resistant organic fibers and inorganic fibers, and molding it into a felt shape. The organic fibers are synthetic fibers such as aromatic polyamide, fluorine, phenol, and nylon, or cellulose pulp, and these can be used alone or in combination, and their shape is that of ordinary fibers. However, it is more preferable to use pulp-like fibers. Further, the conductive filler is a substance selected from carbon, graphite, and metal, and has a powder-like or fibrous form. It is necessary to mix a large amount of powder or short fibrous material, but care must be taken because if the amount is too large, the porosity will decrease and the cushioning properties will deteriorate. The purpose of this conductive filling is not only to prevent static electricity, that is, to provide conductivity, but also to improve thermal conductivity. In other words, it is possible to increase thermal efficiency during hot press molding, quickly heat the object to be pressed, and improve productivity. However, if the thermal conductivity is too high, a sudden temperature rise may adversely affect the performance of some objects to be pressed, so care must be taken. This improvement in thermal conductivity has the effect of reducing heat accumulation, suppressing thermal deterioration, and extending the life of the press, as well as reducing variations in heat conduction and reducing the incidence of defective products in pressed objects. It shows itself. The inorganic fibers in this felt-like material include:
Glass fibers, rock wool, alumina silicate fibers, etc. are preferred, and amorphous fibers containing silicon are particularly desirable. Furthermore, the binder blended into this felt-like material is preferably a heat-resistant resin, particularly a silicon-containing resin. When this silicon-containing resin is used, it has good adhesion to the silicon-containing amorphous fibers, has high heat resistance, makes it easy to ensure cushioning properties, and has a long life. This binder improves the overall strength and at the same time is effective in ensuring an appropriate porosity, that is, maintaining cushioning properties. As described above, the felt-like material of the present invention is a mixture of organic fibers, conductive fillers, inorganic fibers, and binders as essential components. It has become something you can get if you do it. Since this felt-like material contains inorganic fibers, it is likely that the material will fall off, which poses the aforementioned problems, and it is desirable to prevent this. Means for solving the problem By laminating a woven fabric or non-woven fabric made of a conductive fibrous material selected from carbon, graphite, and metal and organic fiber on both or one side of the above-mentioned felt-like material, the fallen objects can be removed. In addition to preventing this, the strength was improved, and the antistatic properties and thermal conductivity of the felt material were not impaired. FIG. 1 is an enlarged schematic longitudinal cross-sectional view of one embodiment of the cushioning material of the present invention. FIG. 2 is an enlarged longitudinal sectional view of another embodiment of the cushioning material of the present invention. As shown in these figures, the present invention has a surface layer 2 laminated on both sides (FIG. 1) or one side (FIG. 2) of a felt-like material 1. This felt-like material 1 is as described above, and has moderate cushioning properties, excellent durability and strength, and its most important features are anti-static properties and good thermal conductivity. It has become extremely useful as a cushioning material during press molding. The present invention provides a surface layer 2 in the form of a woven or non-woven fabric on both or one side of the felt-like material 1.
The fibers that make up this woven or nonwoven fabric are made of conductive fibrous materials and organic fibers. The material of this conductive fibrous material is carbon, graphite,
It is selected from metals, and like the felt-like material 1, it not only imparts antistatic properties to the surface layer 2, but also improves thermal conductivity. Therefore, from the point of view of electrical conductivity and thermal conductivity, it is most preferable for this conductive fibrous material to be a metal fiber, but it is not necessary to have such high conductivity if only to remove static electricity. Also, since very high thermal conductivity is not required, carbon fibers and graphite fibers can also satisfactorily achieve the purpose. The fiber length of this conductive fibrous material does not need to be particularly limited, but it is appropriate to have a fiber diameter of 1 to 25 mm, and a fiber diameter of 1 to 50 μm is preferable. The thinner the material, the higher the cost. The organic fibers in the surface layer 2 preferably have high heat resistance, and aromatic polyamide fibers, phenolic fibers, fluorine fibers, etc. can be suitably used. Please note that thermoplastic organic fibers with a melting point of 200°C or less cannot be used. The reason for this is that when hot pressing is performed, it melts and adheres to the hot plate and mirror plate. Therefore, it is desirable that the organic fiber be one that does not have a thermal melting point and is directly carbonized by high temperatures. However, since this heat pressing is usually carried out at a temperature of about 200°C, thermoplastic fibers can also be used as long as they have a melting point of 200°C or higher. The fiber length and fiber diameter of this organic fiber do not need to be particularly limited, and any form conventionally used as constituent fibers of woven or nonwoven fabrics may be used. The mixing ratio of the conductive fibrous material and organic fiber is 3 to 95% of the conductive fibrous material to the organic fiber.
It can be selected within a wide range, and may be appropriately determined within this range depending on the material of the conductive fibrous material, the type of the object to be pressed, the type and thickness of the felt material 1, etc. As a method for joining the surface layer 2 made of woven or non-woven fabric and the felt-like material 1, for example, a heat-sensitive curing powder adhesive is sprinkled on both or one side of the felt-like material 1, and the surface layer 2 and the surface layer 2 are bonded together by heat pressing. A method of bonding by pressing and thermosetting the powder adhesive can be suitably used. Example As organic fibers, 5 parts by weight of pulp aromatic fiber (trade name: Kevlar, manufactured by Dupont) and 10 parts by weight of phenol fiber (2d x 6 mm, trade name: Kynor, manufactured by Nippon Kynor) were used, and inorganic fibers were used. As the conductive filler, 85 parts by weight of rock wool (average diameter 4μ x average fiber length 120μ, trade name S-Fiber, manufactured by Nippon Steel Chemical Industry Co., Ltd.) was used, and as a conductive filler, carbon fiber (10μ x 3mm, trade name Creca) was used. Manufactured by Kureha Chemical Industry Co., Ltd.)
After dispersing these in water, 5 parts by weight of silicone acrylic resin emulsion (manufactured by Hoechst Synthesis) was added, and a fixing agent was added to fix the resin to the fibers. A sheet with a thickness of 1.2 mm and a density of 0.67 g/cm ³ was produced by papermaking and drying. Five of these sheets were pasted together using thermosetting silicone adhesive, and the surface was covered with a woven fabric blend of aramid fiber and carbon fiber (carbon fiber amount: 10
%) and hot pressed at 180°C and 70Kg/cm ² to obtain a board with a thickness of 4.5mm. Comparative Example A board was obtained in the same manner as in the above Example except that an aramid fiber woven fabric was used instead of the aramid fiber and carbon fiber blend fabric. These were used as cushioning materials for molding PVC resin plates. In addition, resin plate molding is heated at 170℃ and 20Kg/ ^cm2 .
This was done using a cycle of 40 minutes and 40 minutes of cooling. These initial physical properties and physical properties after 500 cycles of use were measured. The results are shown in the table below.

[Table] The compression ratio is the value when a load of 20Kg/cm ² is applied at 170℃, and it is calculated as the initial thickness - thickness at load / initial thickness x 100, and the recovery ratio is the value when a load of 20Kg/cm2 is applied. It is indicated by the percentage of the initial thickness that is restored when restored. In both Examples and Comparative Examples, there was no inorganic fiber falling off, and compared to products without woven fabric, handling was very good, and the number of defective products was significantly reduced.
In addition, when looking at the initial physical properties of Examples and Comparative Examples, there are no major differences other than a large difference in electrical conductivity; however, in practical tests, the Comparative Examples exhibited frequent adhesion of dust, etc. due to static electricity, and after 450 cycles. From now on,
There were many defective products due to variations in heat conduction. This is thought to be because the comparison example has a large amount of internal heat accumulation, and as a result, internal deterioration is likely to occur. In fact, when we looked at the internal state of the cushioning material after the test, we found that the comparative example had greater discoloration and more advanced deterioration than the example. In this way, the present invention is based on the above-mentioned invention (patent application filed in 1983-
By applying a woven or non-woven fabric containing conductive fibers to the cushioning material of No. 177436), it not only prevents adhesion to the mirror plate, improves strength, and prevents fibers from falling off, but also fully maintains the characteristics of the cushioning material of the invention. It is something that can be demonstrated. C. Effects of the invention As explained in detail above, the present invention is based on the felt-like material disclosed in the above-mentioned patent application (Japanese Patent Application No. 177436/1982) as a useful cushioning material, that is, imparting antistatic properties and heat conduction. This is a further improved press cushioning material that aims to improve the efficiency, and is made by laminating woven or nonwoven fabric containing conductive fibers on both or one side of this felt-like material, and its effects are as follows: This means that it prevents the inorganic fibers from falling off and improves workability, and at the same time prevents the production of defective products because there is no adhesion of fallen matter. Moreover, the surface layer of the present invention prevents adhesion to the mirror plate and improves its strength.Furthermore, since this surface layer contains conductive fibrous material, it reduces the properties of the felt-like material described above. It also has the remarkable effect of maintaining and improving excellent antistatic properties and thermal conductivity.

[Brief explanation of the drawing]

FIG. 1 is an enlarged schematic longitudinal cross-sectional view of one embodiment of the cushioning material of the present invention. FIG. 2 is an enlarged longitudinal sectional view of another embodiment of the cushioning material of the present invention. 1...Felt-like material, 2...Surface layer.

Claims (1)

[Claims for Utility Model Registration] 1. Woven or non-woven fabric made of conductive fibers and organic fibers on both or one side of a felt-like product made by blending organic fibers, conductive fillers, inorganic fibers, and binders. A cushioning material for presses characterized by laminated layers. 2. The cushioning material for a press according to claim 1, wherein the conductive filler and the conductive fibrous material are both selected from carbon, graphite, and metal.