JPS6360715A - Heat-resistant cushion material for molding press - Google Patents

Abstract

PURPOSE:To obtain a cushion material for a molding machine which is used at the time of molding, by a method wherein wet paper composed of a specific heat-resistant polymer is molded and an arbitrary number of sheets of wet paper are laminated after water content of the wet paper has been controlled so as to fall within a specific range, which is unified by drying through dehydration under heating and pressurization. CONSTITUTION:Wet paper is molded by performing sheet forming of aqueous slurry obtained by mixing a fine inorganic fiber whose fiber diameter not containing shot practically is 0.5-1.5mum and fiber length is 70-1,000mum and pulley particles of a heat-resistant aromatic polymer whose water filtering value is 150sec or more and less than 500sec with each other. After an arbitary number of sheets of wet paper, whose water content has been controlled to 50-95%, have been laminated, the same is unified by drying through dehydration under heating and pressurization. Interlaminar bonding of sheets of paper is performed sufficiently as mentioned above and a cushion material superior in cushioning function, mechanical strength, heat resistance and durability is obtained. When water content is lower than 50%, in the case where the sheets of wet paper are dried by laminating them, interlaminar bonding of sheets of paper is weak and they are not turned into a monolithic cushion material. When the water content is higher than 95%, the wet paper is collapsable, lamination is difficult and cracks are generated during pressurization and heating.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a cushioning material for a press molding machine used in molding laminates and the like.

(B) Prior Art Cushioning materials for press molding machines are required to have sufficient heat resistance and cushioning properties since considerable heat and pressure are applied during the molding process.

Conventionally, in this field, composite materials made of asbestos fibers in the form of sheets, plates, or formed into specific shapes have often been used. However, in recent years, composite materials using rock wool fibers, which are free from the harmful effects of asbestos fibers on the human body, have come into use. (For example, JP-A No. 5
9-192795) (C) Problems to be solved In the case of rock wool composite materials, the rock wool fibers are extremely fine and brittle, so during repeated pressing, powder caused by the fibers is generated and the pressing There was a problem with the process. In order to solve this problem, a method has been adopted in which, for example, another heat-resistant sheet is attached to both sides or end faces of the cushion material using a heat-resistant adhesive. (Unexamined Japanese Patent Publication No. 61-6
(No. 1839, No. 61-70027) However, in this case, since the rock wool composite material absorbs a large amount of adhesive, a large amount of adhesive is required, and the area hardens, resulting in poor cushioning properties. Furthermore, it requires considerable skill and effort to attach the heat-resistant sheet without wrinkles.

Furthermore, there were other problems such as the lack of an adhesive with satisfactory properties that could withstand repeated pressing under high temperature and high pressure.

(D>Means for solving the problem) The above problem can be solved by using a pulp-like heat-resistant aromatic polymer that does not contain rock wool components on both the upper and lower surfaces of the cushioning material and/or any part of the intermediate layer. This problem can be solved by providing a heat-resistant sheet layer containing particles and fibrids as a main component when manufacturing the cushion material.

That is, the cushioning material in the present invention contains pulp-like particles of rock wool fiber and heat-resistant aromatic polymer in a ratio of 90-60%.
: Tsubo M80- made by mixing at a ratio of 10-40% by weight
60 g/m of wet paper and pulp-like particles of a heat-resistant aromatic polymer containing no rock wool fibers and 100 g/m of the same fibers.
50: Basis weight 5-30 consisting of a proportion of 0-50% by weight
9/m wet paper is laminated in multiple layers so that a heat-resistant layer consisting of pulp-like particles of a heat-resistant aromatic polymer and fibers is placed on at least the upper and lower surfaces of the substrate and any intermediate layer. , is a heat-resistant cushioning material characterized by being integrated by heating and pressurizing.

Therefore, it does not contain any adhesives or the like that are unfavorable in terms of performance as a finished cushioning material.

In order to increase the mechanical strength of the upper and lower layers in the above papermaking process, aromatic polyamide fibers are added to the pulp-like particles of the heat-resistant aromatic polymer as a papermaking raw material.

(E) Function of the invention Cushioning materials whose main components are rock wool and pulp-like particles of heat-resistant aromatic polymers are very useful as a substitute for cushioning materials containing asbestos, but the elastic modulus of the rock wool used is Because it was too expensive and the fiber length was too short, it had the disadvantage that rock wool powder came out during use.

This combination of papermaking makes it possible to almost completely prevent the powder from falling off. The method of joining sheets together using an adhesive has the advantage that it can be easily carried out using the conventional circular mesh method.

Furthermore, the sheet used for paper binding (~ is the aromatic polyamide fiber and pulp-like particles used in the cushioning material, so it is very compatible with the fibers and pulp-like particles, and the special adhesive (~)
It does not require heat resistance and a certain degree of elasticity.

By providing a heat-resistant wet paper layer in the middle layer of the cushioning material, which is a wet paper made solely of pulp-like particles of a heat-resistant aromatic polymer, or a mixed paper made of pulp-like particles and fibers of a heat-resistant aromatic polymer. It is also possible to improve the delamination strength, which has been weak in the past, even in thick cushioning materials.

The present invention uses fine inorganic fibers and pulp-like particles of an aromatic polymer, but the elastic modulus of the fine inorganic fibers and the pulp-like particles of an aromatic polymer are significantly different (the former is more than the latter high elastic modulus) and fine front Ia, ii
The fibers and the pulp-like particles of the heat-resistant aromatic polymer have significantly different shapes, and this combination of different shapes increases the porosity, which preferably provides an excellent cushioning function.

In general, in a sheet made only of polymers, the fibers and the bulb particles are made of the same polymer, so they are compatible with each other, and the elastic modulus is lower than that of non-Ia fibers.
There are few voids between the fibers and the pulp particles, and the cushioning function is also unsatisfactory.

The inorganic fibers referred to in the present invention include rock wool, ceramic fibers, glass fibers, etc., and have fiber diameters of o, 5-'15*,
Those with an R fiber length of 70-1000 tans are used. Also,
It is essential not to include so-called shot that does not become fibers at the time of fiberization.

If shots are included, the texture is poor and the shots tend to come off easily, and the strength is also negative.

Furthermore, when used as a cushioning material, it is undesirable as it may damage the end plate. When the fiber diameter is less than 0.511rt,
The resulting cushioning material has a low porosity, which is undesirable. On the other hand, if it exceeds 15 IIn, the inorganic fibers protrude from the surface, making it undesirable to the touch. Furthermore, if the fiber length is less than 70 IIn, the yield during paper making will be poor, and the physical properties of the resulting sheet will be poor, making it impractical. On the other hand, the fiber length is 10ooII! If it exceeds t, the uniform dispersibility in water will be extremely poor and the R fibers will bunch up, resulting in poor thickness uniformity and smoothness of the resulting cushion material, and the cushion material will tend to curl.

The pulp-like particles of the heat-resistant aromatic polymer used in the present invention are composed of aromatic polyamide or aromatic polyamide-imide.

The pulp-like particles used in the present invention refer to fibrous, thin film-like, or ribbon-like particles having a large number of protrusions that can be made into a paper-like structure using a paper machine, and are aromatic particles. It is obtained by introducing a solution of the polymer into a precipitant and precipitating it as fine particles. For example, Japanese Patent Publication No. 37-5732 discloses an example of its production method, but the production method is not limited thereto, and any polymer particles having the ability to form wet paper may be used.

The pulp-like particles of the polymer used in the present invention are those exhibiting a freeness value of 150 seconds or more and less than 500 seconds according to the test method described below. The drainage value is 160 seconds or more, 40
More preferably, the time is less than 0 seconds.

Coarse pulp-like particles exhibiting a value of less than 150 seconds have too long fiber length, and the dispersibility of the slurry mixed with inorganic 11 fibers is significantly deteriorated, and the formation is poor during paper layer formation (paper making), resulting in poor physical strength. I only get bad seats. On the other hand, the filtration value is 50
Fine pulp-like particles exceeding 0 seconds had good dispersibility, but poor paper layer formation, dewatering and water squeezing properties, and were not preferable in terms of papermaking efficiency.

Note that the freeness value in the present invention is a value for evaluating the freeness of pulp obtained by the following test method.

That is, the pulp particles are adjusted to a 0.3% aqueous dispersion (20°C), and 1 liter of this is collected. When this slurry is transferred to a cylindrical container with an internal diameter of 102 m (the bottom is lined with a 78-mesh wire mesh), the time required to obtain 500 r111 of filtrate is called the filtration value, expressed in seconds.

As mentioned above, the heat-resistant cushion material for molding presses of the present invention has a fiber system substantially free of shot, with a fiber content of 0.5-15%.
Wet paper is produced by wet papermaking of an aqueous slurry made by mixing fine non-*gi4 fibers with a fiber length of 70 to 1000 m and pulp-like particles of a heat-resistant aromatic polymer with a freeness value of 150 seconds to less than 500 seconds. It is obtained by laminating any number of sheets of wet paper with a moisture content adjusted to 50-95%, and then dehydrating and drying them under heat and pressure to integrate them. The weight ratio of the fibers to the pulp-like particles of the heat-resistant aromatic polymer is appropriately selected within the range of 50:50-95:5.

According to the present invention, pulp-like particles of a heat-resistant aromatic polymer and inorganic fibers are mixed to form an aqueous slurry,
Wet paper is formed using a paper machine such as a cylinder type or an inclined wire type.

The moisture content of wet paper is reduced to 50-95 by inhalation or squeezing.
%. If the moisture content of wet paper is less than 50%,
When wet paper is layered and dried, the adhesion between the paper layers is weak and the paper does not form an integrated cushioning material. Also, if the moisture content is more than 95%, the wet paper will crumble and it will be difficult to form the VI layer.
Cracks occur during pressure heating.

As described above, a cushioning material with sufficient adhesion between paper layers, a uniform and integrated structure, and excellent cushioning function, mechanical strength, heat resistance and durability can be obtained.

(F) Example 30 parts of pulp-like particles of a heat-resistant aromatic polymer and 70 parts of shot-free fine rock wool fibers having an average fiber length of 250IIft and an average diameter of 4°11In were mixed, and the solid content temperature Make a 1% aqueous slurry.

When a wet paper is formed from this aqueous slurry using a cylinder paper machine, the tsubo f! Mix 15 g/m wet paper. As shown in Fig. 1, the required number of sheets of this composite wet paper were laminated so that the layers consisting only of the pulp-like material of the heat-resistant aromatic polymer were on both the top and bottom surfaces, and then hot pressed at 4ONy/crA, 140'C. They were dried under pressure and heat to obtain a board-like object.

Comparative Example 1 A cushioning material (Japanese Unexamined Patent Publication No. 192795/1989) made of a mixed wet paper made of only rock wool fibers and a pulp-like material of a heat-resistant aromatic polymer as the conventional one was used as a comparative example.

Comparative Example 2 Further, as the cushioning material used in Comparative Example 1, a melamine-treated twill weave Nomex cloth was heated and integrated using a nitrile rubber adhesive.

The above cushioning material is an epoxy resin laminate plate.

(G) Effects of the Invention According to the present invention, it is possible to relatively easily obtain a cushioning material having satisfactory properties that can withstand repeated pressing at high temperatures and pressures.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a cross section of a wet paper web after lamination according to an embodiment of the present invention. Leather LJD □-ra□□-ra□□□□□□□□□-4” 127 Hani Shifu・1 sentence゛To pull”+Single bond 1 1 521 Kikeno & ↓

Claims (1)

[Claims] 1) Fiber diameter that does not substantially contain shot is 0.5-15
Wet paper and inorganic fibers made from an aqueous slurry made by mixing fine inorganic fibers with a fiber length of 70-1000 μm and pulp-like particles of a heat-resistant aromatic polymer with a freeness value of 150 seconds or more and less than 500 seconds. After molding a wet paper made of a heat-resistant polymer that does not contain any Heat-resistant cushioning material for integrally molded press cushions. 2) The wet paper made of a heat-resistant polymer is a wet paper made solely of pulp-like particles of a heat-resistant aromatic polymer, or a mixed paper of pulp-like particles and fibers of a heat-resistant aromatic polymer. 1
Cushion material as described in section. 3) The cushioning material according to claims 1-2, wherein heat-resistant wet paper is provided on both upper and lower surfaces of the cushioning material. 4) The cushioning material according to claims 1-2, wherein heat-resistant wet paper is provided on both upper and lower surfaces of the cushioning material and in the middle layer.