JPH0929010A - Thermoplastic resin 3-layer filter plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a thermoplastic resin multilayer filter plate provided with elasticity higher than those of both outer face layers and high strength by forming both outer face layers and a central layer of resin of same quality and containing a filler in the central layer. SOLUTION: A filter plate is composed of three layers, and three layers are composed of thermoplastic resin of same quality such as polypropylene resin and provided with resistance to corrosion, resistance to chemicals and the like. A filter such as talc or mica is contained in a central layer to provide elasticity higher than those of both outer face layers. Both outer layers are provided with cutting processability by the arrangement, and the whole strength is improved by the central layer of high elasticity, and the filter plate durable in the use at the high temperature and under the high pressure is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin filter plate used in a filter press (batch pressure type solid-liquid separator).

[0002]

2. Description of the Related Art Conventionally, a filter plate for a filter press uses a single type of thermoplastic resin to be heated and melted by an extrusion method or a pressing method to form a rectangular plate or an original plate of an approximate shape, which causes distortion. The product was obtained by forming into a predetermined shape by a molding method in which the product was removed and then mechanically cut. However, because the whole is the same resin, in order to increase the strength to withstand high temperature and high pressure use, the plate thickness must be increased, and the plate thickness is reduced without decreasing the strength due to the machine length. When I wanted to, I had to use expensive resin. Therefore, there is a problem that the use conditions of the filter plate are restricted due to the cost, weight and size restrictions.

It is also possible to add a filler to the resin to increase the rigidity, but a resin containing a large amount of the filler is difficult to perform precision cutting, and a smooth cutting surface cannot be obtained, It is not practical because the fine irregularities formed become brittle.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and its gist is a thermoplastic resin filter plate for a filter press, which comprises both outer surface layers and a central layer. Is a resin of the same quality, and since the central layer contains a filler, the elastic modulus is higher than both outer surface layers.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The thermoplastic resin used as the material of the filter plate in the present invention is a resin having corrosion resistance and chemical resistance, and typically, a polypropylene resin which is a relatively inexpensive resin can be mentioned. Further, ABS resin, polyethylene resin, etc. may be used. The filter plate is composed of three layers, and the three layers are composed of the same resin, but the core layer contains a filler, so that the elastic modulus is higher than that of both outer surface layers.

As the filler, one or more kinds of natural minerals such as talc, mica, asbestos and kaolin, and synthetic fillers such as glass fiber and glass flakes can be used, and generally about 100 to 1000. Fine powder or fine needle-shaped particles of about mesh size are preferable. The amount of the filler added is preferably about 10 to 40% by weight from the viewpoint of strength to be obtained and easiness of plate molding. By including a filler in the central layer, for example, in the case of polypropylene resin, about 10,000 to 30,000 kg without filling
Elastic modulus in the range of f / cm ² (JIS K 71
13) is larger than its original value and is about 20,000-
It can be increased up to 80,000 kgf / cm ² . The method of mixing the resin and the filler may be a method of kneading when molding into a plate shape, a floating suspension method, or the like.

It is preferable that both outer surface layers contain substantially no filler, but a small amount of filler can be added as long as the machinability is not impaired. As for the thickness ratio between both outer surface layers and the center layer, the strength improves as the center layer thickness increases, but both outer surface layers need to have a thickness of at least the cutting depth,
The thickness ratio can be set depending on the final shape of the filter plate and the like.

In order to obtain such a laminate, a method of forming both the outer surface layer and the central layer by a pressing method, an extrusion molding method or the like, and then thermocompression bonding can be used. Since both outer surface layers and the center layer are made of the same resin, they can be firmly fused at the interface. As another method, a method of coextruding both outer surface layers and the center layer can be used.

In order to make a filter plate, a rectangular plate or an original plate having an approximate shape is prepared as in the conventional case, the strain is removed, and then the outer surface is mechanically cut. However, no filler is added to the outer surface layer. Since only a small amount is added, precise cutting can be performed without any problems. Since the outer peripheral portion is not required to be finely cut, it can be cut without any trouble even if the central layer is present.

[0011]

According to the present invention, both outer surface layers and the central layer are made of the same resin, and the central layer contains a filler.
Since the thermoplastic resin three-layer filter plate has a higher elastic modulus than both outer surface layers, both outer surface layers have good machinability,
Since the core layer with high elastic modulus improves the overall strength, it can be used as a filter plate that can withstand high temperature and high pressure use without increasing the plate thickness, suppressing cost up and greatly increasing machine length. be able to.

Claims (1)

[Claims] 1. A filter plate made of a thermoplastic resin for a filter press, wherein both outer surface layers and the center layer are made of the same resin, and the center layer contains a filler so that the outer layer is more elastic than the both outer surface layers. Thermoplastic resin three-layer filter plate characterized by a high rate.