JPH03368Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to a cushion material for high-temperature, high-pressure molding presses used in the production of synthetic resin laminates, PVC sheets, printed circuit boards, multilayer boards, etc. Conventional technology and its problems Phenol resin laminates, epoxy resin laminates, etc. are produced by laminating the required number of so-called B-stage prepregs, which are made by impregnating a base material such as paper or glass cloth with resin and pre-curing it. Depending on the temperature, decorative paper, steel foil, etc. are layered and sandwiched between the mirror plates, and the cushion material is placed between the press heating plates to adjust the temperature.
It is manufactured by fluidizing and curing the resin under heating and pressure at 150 to 190°C and a pressure of about 40 to 100 kg/cm ² and then molding it. Conventionally, cushion materials used in such applications have been made by laminating woven fabrics made of glass fiber with rubber sheets such as butyl rubber interposed between them to form a plate-shaped body, and thin plates such as aluminum sheets are attached to the upper and lower outer surfaces of the plate-shaped body. A cushion material for molding presses that is bonded and integrated has been proposed (Utility Model Publication No. 14165, 1983). However, due to the fact that this cushion material uses a heat-resistant rubber sheet as a main component to provide the desired cushioning properties, the rubber sheet is generally used repeatedly under high temperature and high pressure. So-called fatigue occurs relatively early in the cushioning material, and this permanent deformation causes dimensional changes in the vertical and lateral directions, resulting in uneven thickness and uneven pressure distribution and heat conduction rate. There was an essential problem that its useful life was relatively short. In addition, for the purpose of improving such problems, as one of the other conventional techniques, the core portion is composed of a heat-resistant fibrous nonwoven fabric impregnated with resin or rubber and hardened, and heat-resistant A cushion material has been proposed in which a cushionable surface fiber layer made of non-woven fiber fabric is formed (Utility Model Application Publication No. 7646/1983). However, even with the cushion material of this prior proposal, due to repeated use under high temperature and high pressure, there is an undeniable tendency for harmful fatigue to occur in the core portion relatively early, and sufficient satisfaction can be obtained in terms of durability. It wasn't something. The present invention has been developed in view of the problems of the prior art described above.
It was completed as a result of intensive research with the aim of suppressing harmful deformation while maintaining the required cushioning properties, which is one of the main characteristics required for cushioning materials for molding presses. That is, an object of the present invention is to provide a cushion material for a molding press that has excellent durability and exhibits little dimensional change, and thus does not cause a significant change in thickness. Means for Solving the Problems The present invention, as a means to achieve the above-mentioned object, eliminates or significantly reduces the existence of a single rubber sheet layer, which is the main cause of sagging, and The main feature is that the main constituent material is fiber cloth, which has excellent expansion and contraction control properties. That is, in the present invention, a plurality of heat-resistant fiber cloths
At least one of their contact surfaces is characterized by having a plate-shaped core part that is laminated and integrated through a thin binder layer made of rubber or resin that has been integrally coated in advance by means of coating or impregnation. The object of the present invention is to provide a cushion material for a molding press, in which surface fiber layers made of heat-resistant fibers are integrally laminated and bonded on both sides of the plate-shaped core portion via an adhesive layer. Detailed Description of the Structure In the above structure, as the material of the heat-resistant fiber cloth, inorganic fibers and organic fibers are used alone or in combination. Examples of inorganic fibers include glass fibers and metal fibers, and examples of organic fibers include synthetic fibers such as polyamide fibers, aromatic polyamides, and polyester fibers, and natural fibers. Further, the binder layer coated on at least one surface of the heat-resistant fiber cloth serves to maintain the required elastic restoring force for a long period of time and to bond the cloths together with the fiber cloth. As the resin used for this purpose, heat-resistant resins such as polyester resins, epoxy resins, acrylic resins, silicone resins, polyamide resins, and polyimide resins are used. In addition, the rubber may be a rubber paste prepared by diluting heat-resistant rubber compounds such as fluoro rubber, silicone rubber, butyl rubber, or ethylene/propylene rubber alone or in a blend with a solvent such as toluene or xylene, or a heat-resistant rubber compound as exemplified above. Rubber latex is used. The most common and simple method for coating the heat-resistant fiber cloth with the above-mentioned resin or rubber is the roll coater method using a coating machine, the bar coater method, etc., but the dipping method etc. It is also permissible to impregnate a fiber cloth with a binder so that both surfaces thereof are coated with a thin layer of binder. The binder layer does not necessarily need to be provided in advance on all fiber cloths to be laminated. In short, it is sufficient that at least one of the contact surfaces of the mutually laminated fiber cloths is coated. Therefore, in order to obtain advantages in manufacturing the cushion material, in particular to ensure that air bubbles are not left inside during lamination, for example, one intermediate layer may be made of one sheet without a binder layer. It is advantageous to use the fiber cloth as it is, and to laminate one or more fiber cloths on both sides of which a binder layer is formed only on one side by a coating method. In this case, it is preferable to use glass cloth as the intermediate fiber cloth without one binder layer. The reason why the means for forming the binder layer is limited to coating or impregnation is to enable the formation of a layer as thin as possible within the range that can achieve the purpose of bonding the fiber cloths together. The amount of binder in the binder layer is, for example, in the case of rubber glue, set to about 500 to 1000 g/m ² per unit area of the fiber cloth, particularly preferably about 700 g/m ² as a coating amount. . The number of layers of fiber cloth as mentioned above is 3 to 7.
There are about 5 pieces, preferably about 5 pieces, and the core formed by these pieces is usually a hard plate-like body with a thickness of about 1.5 to 2.5 mm. The surface fiber layers laminated and bonded on both sides of the core portion form a relatively soft cushion layer, and include heat-resistant fiber cloth made of the same material as that used for the core portion, or non-woven fabric, Alternatively, it may be further composed of a laminate of fiber cloth and nonwoven fabric. Here, when using nonwoven fabric,
The nonwoven fabric has a basis weight of 300~ without impregnation with a binder.
50 to 400 fibers/cm ² for complex fibers of about 1500g/m ²
A needle-punched material is preferably used. As the adhesive layer for bonding and integrating the surface fiber layer to both sides of the core part, a prepreg prepared by impregnating a base material such as a nonwoven fabric or cloth with a resin and precuring it, a heat-resistant adhesive, a hot melt film, or the like is used. Examples of prepreg include nylon nonwoven fabric impregnated with epoxy resin, glass cloth impregnated with polyimide resin or epoxy-silicon modified resin, and heat-resistant adhesives such as polyamide resin and polyimide resin. As hot melt films, fluororesin-based, polyamideimide resin-based, fluoro-rubber-based, silicone rubber-based, etc.
Each is listed as a specific example. In addition, in order to further improve the thermal conductivity and heat dispersion of the cushion material itself for molding presses, a rigid heat transfer sheet having higher thermal conductivity may be interposed between the core portion and the surface fiber layer, if necessary. Sometimes I let them do it. For example, this rigid heat transfer sheet has a thickness of
A metal foil of iron, aluminum, or an alloy thereof having a thickness of approximately 0.01 to 0.1 mm, a heat-resistant synthetic resin sheet containing metal fibers or metal powder dispersed therein, or a porous sheet thereof may be used. Furthermore, if necessary, a release layer may be additionally formed on the surface of the heat-resistant surface fiber layer. The release layer may be, for example, a fluororesin-based synthetic resin film, silicone rubber, a cloth made of heat-resistant fibers such as aromatic polyamide fibers, a metal plate such as steel foil,
It is made of heat-resistant paper such as aromatic polyamide paper, and is bonded and integrated onto the surface fiber layer via the same adhesive layer as described above. To manufacture the cushion material for molding press according to the present invention as described above, first, the core part is laminated and integrated by hot pressing, and then a surface fiber layer is overlaid on both sides with an adhesive layer interposed therebetween, and the whole is hot pressed again. This is done by laminating them together, or by layering the fiber cloth with a binder that makes up the core, then layering a surface fiber layer via an adhesive layer, and then joining and integrating the whole thing at once using a hot press. . Effects of the Invention The present invention has the following effects based on the above-described configuration. The cushioning material itself for a molding press exhibits little wear and dimensional change, making it possible to manufacture products such as synthetic resin laminates with high uniformity and precision over a long period of time. That is, in the cushion material for molding presses of the present invention, the core portion in the middle of its thickness is composed of a laminate of a plurality of fiber cloths that themselves have excellent expansion/contraction regulating effects, particularly heat-resistant fiber cloths, and Since the fiber cloths are laminated and integrated through a thin adhesive layer that has been integrally coated on at least one of their contact surfaces by coating or impregnating, the rubber The layer of binder made of synthetic resin is present inside as an extremely thin layer, and does not cause any harmful effects as a cause of sag in the thickness direction of the cushion material.
In addition, the binder layer exists in a partially impregnated state between the fibers of the fiber cloth due to the hot-press molding of the core portion, and also acts as a binder between the fibers of the cloth itself. It supplements the elastic restoring force of the cloth, prevents the fiber interlacing structure from collapsing, and also prevents the cloth itself from becoming sagging. Therefore, even if large pressure is repeatedly applied to the core portion, the dimensional change and settling of the thickness are small, and the thickness does not decrease significantly over time. On the other hand, since the core part is composed of fiber cloth and a binder layer made of rubber or resin, it is required for cushion materials to have these material properties as well as a surface fiber layer. While it possesses the necessary cushioning properties to a comparable degree, as mentioned above, the thickness changes little over time, making it possible to transmit uniform pressure over the entire surface during use. At the same time, the heat transfer rate in the thickness direction of the core part can be controlled to be almost constant at all times, resulting in excellent temperature rise characteristics, which can always exert a constant and good thermal effect on the laminate being molded, making it uniform. This enables high-quality manufacturing. The service life of the cushion material can be significantly increased. That is, as mentioned above, the core part is less likely to set, and the dimensional accuracy and thickness accuracy of the cushion material can be maintained well over a long period of time.
The life of the cushion material itself can be further improved compared to conventional products. It can be manufactured relatively easily and has excellent thickness accuracy. That is, not only the fiber cloth with a binder layer, which is a component of the core part, but also the adhesive layer made of prepreg, etc., and the surface fiber layer are all sheet-like or film-like, which are easy to handle. Since they can be manufactured by stacking them in a predetermined order and hot-pressing them, the manufacturing process can be carried out easily and efficiently, and since there is no intervening thick sheet-like rubber layer, the hot-pressing process during manufacturing can be There is no fear that the thickness accuracy will deteriorate due to deformation of the rubber layer, and the thickness accuracy can be extremely excellent throughout. Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. Example 1 This is shown in Fig. 1 and was manufactured according to the following specifications. The core part 1 is made by placing a glass cloth 2 weighing 210 g/m ² in the center, and laminating and integrating two sheets of fiber cloth 3 on each side with a binder layer 4 formed on one side. And so. Above fiber cloth 3
is made of 6.6 nylon fiber with a thickness of 0.35 mm and a weight of 200 g/ ^m2 , and the binder layer 4 is a 30% rubber solution prepared by diluting a butyl rubber compound with toluene, which is coated with a fiber cloth 3 using a bar coater. It was coated on one side of the paper at a rate of 70 g/m ² and air-dried for 2 days. The overall thickness of the fiber cloth 3 with the binder layer 4 thus obtained is approximately 0.45
mm and weighed 410 g/m ² . The surface fiber layer 5, which also acts as a release layer on both sides of the core portion, was made of a twilled aromatic polyamide fiber cloth with a thickness of 0.40 mm and a weight of 210 g/m ² . Further, as the adhesive layer 6 for bonding these together, a prepreg sheet made of a thin nylon fiber nonwoven fabric impregnated with an epoxy resin adhesive was used. Then, the above materials are layered in a predetermined order and heated and pressed using a hot press at a temperature of 160°C, a pressure of 20 kg/cm, and a pressure time of 60 minutes, and the whole is laminated and bonded into one piece at once, resulting in an overall thickness of approximately A cushion material A for a molding press with a thickness of 2.0 mm was obtained. Example 2 Glass cloth with a weight of 210 g/m ² was used as the heat-resistant fiber cloth 3 constituting the core part 1 of Example 1,
Otherwise, a desired cushion material was obtained in exactly the same manner as in Example 1. Embodiment 3 In the structure of the core part 11, which is shown in FIG.
2 was used, and the surface fiber layer 21 was constituted by a laminate of a heat-resistant fiber nonwoven fabric 22 and a heat-resistant fiber cloth 23. Therefore, the nonwoven fabric 22
This embodiment differs from the first embodiment in that an adhesive layer 24 is further interposed between the fiber cloth 23 and the fiber cloth 23. Other constituent items, molding conditions, etc. are the same as in Example 1, and corresponding parts are designated by the same reference numerals and detailed explanation thereof will be omitted. In addition, the above nonwoven fabric 2
In No. 2, a 6.6 nylon fiber with a basis weight of 1000 g/m ² was needle-punched at a density of 300 fibers/cm ² . The outermost fiber cloth 23, which also serves as a release layer, was made of the same aromatic polyamide fiber as in Example 1. The cushion material B according to this example has an overall thickness of approximately
It was 5.0mm. Comparative Example 1 According to the prior art described above (Utility Model Publication No. 37-14165), two rubber sheets with a thickness of 0.7 mm and three glass cloths made of the same material as those used in Example 1 were alternately used. A core portion was formed by laminating and integrating the layers, and surface fiber layers similar to those in Example 1 were formed on both sides of the core portion to obtain a cushion material with a thickness of approximately 2.0 mm. Comparative Example 2 Another conventional technology mentioned above (Utility Model No. 58-
7646), a nonwoven fabric made of aromatic polyamide fiber with a basis weight of 700 g/m ² and a number of needle punches of 200/cm ² impregnated with 30 wt% melamine resin was used as the material for the core part. Surface fiber layers similar to those in Example 1 were formed on both sides of the core portion to obtain a cushion material with a thickness of 1.8 mm. [Comparative Test] In order to investigate the durability performance of each cushion material according to Examples 1 to 3 and Comparative Examples 1 and 2 above, they were
Take a test piece of size 300mm x 300mm and heat it at 180℃
After heating and pressurizing for 80Kg/ ^cm2 x 60 minutes, we repeated a heat-pressure test in which the pressure was decompressed for 20 minutes, measured the dimensional changes in the plane direction of each cushion material after 200 heat-pressure tests, and calculated their elongation rates. I asked for it. The results are shown in Table 1 below.

[Table] As shown in the results in Table 1 above, the cushion material based on the present invention clearly exhibits less fatigue and is superior in durability compared to the core structure based on the conventional technology. was confirmed.

[Brief explanation of the drawing]

FIGS. 1 and 2 are configuration diagrams showing different embodiments of each invention. 1, 11...Core part, 2...Glass cloth, 3
...Fiber cloth, 4...Binder layer, 5,21...
Surface fiber layer, 6...Adhesive layer, 22...Nonwoven fabric,
23...Fiber cloth.

Claims (1)

[Claims for Utility Model Registration] (1) A thin layer of rubber or resin in which a plurality of sheets of heat-resistant fiber cloth are integrally coated on at least one of their contact surfaces by means of coating or impregnation. It is characterized by having a plate-shaped core part that is laminated and integrated through a binder layer, and surface fiber layers made of heat-resistant fibers are laminated and adhesively integrated on both sides of the plate-shaped core part through an adhesive layer. Cushion material for molding presses. (2) The cushion material for a molding press according to claim 1, wherein the binder layer is formed by applying rubber glue. (3) The core part consists of one heat-resistant fiber cloth without a binder layer in the middle, and one or more heat-resistant fiber cloths each having a binder layer formed by coating on one side on both sides. A cushion material for a forming press according to claim 1 or 2, which is a laminated material. (4) The cushion material for a forming press according to claim 3, wherein the intermediate heat-resistant fiber cloth having no binder layer is made of glass fiber cloth.