JPS6318421Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a gas or This invention relates to a filter element that allows liquid to pass through, and particularly to a filter element made of wet paper that has excellent oil resistance.

Conventionally, knitted fabrics, nonwoven fabrics, and paper made of various natural fibers, organic chemical fibers, and inorganic fibers have been widely used as filter element materials.

However, in fields where oil resistance is required, glass fiber is mainly used. Glass fiber filters are more expensive than filters using general-purpose organic chemical fibers, and are not compatible with organic synthetic fibers, making it difficult to mix them together.

The inventors of the present invention conducted various studies in light of these problems and found that a filter element made of wet paper that contains composite fibers containing EVA as one component is superior in both quality and manufacturing process. .

In other words, the filter element according to the present invention not only has high filter efficiency, but also exhibits the oil resistance characteristic of EVA, and has good oil resistance, and can continuously remove foreign substances from various oils over a long period of time. can. Furthermore, unlike general non-woven fabric filters, the cake layer has good removability and can be backwashed and reused. These performances can be arbitrarily controlled by selecting ranges such as fiber fineness and paper making conditions.

On the other hand, in the process of wet paper making for filter elements of the present invention, it is easy to bond with wet heat while absorbing water.
Also, there is no problem with adhesion after the water evaporates. or
Since EVA has a binder effect, it is possible to heat-fuse the fibers together during the drying process during the normal papermaking process, without having to mix other heat-sealable fibers or apply a secondary bonding process. A bond is formed and the paper has extremely strong paper strength.

The EVA of the present invention is a saponified ethylene/vinyl acetate copolymer having an ethylene content of 30 to 70 mol% and a degree of saponification of the vinyl acetate portion of 98 mol% or more. When the ethylene content is below 30 mol%, thermal decomposition makes it impossible to perform hot-melt composite spinning using EVA in combination with any thermoplastic polymer.
Moreover, when the melting point is 180°C or higher, it becomes difficult to perform adhesive processing. Also, if the ethylene content is 70 mol% or more, EVA
The oil resistance of the material decreases rapidly, it is difficult to bond with wet heat during the papermaking process, and it tends to stick when bonded with dry heat, which is also undesirable. If the degree of saponification is less than 98 mol%, the selection range of the other composite component will be narrowed during hot-melt composite spinning, and it will tend to stick during the fiber or paper manufacturing process.

Other thermoplastic polymers that can be composite-spun with EVA include polyolefins, polyesters, polyamides, and other materials that can be melt-spun.

The composite fiber of the present invention is used in an amount of 50% or more by weight as the paper material obtained by wet papermaking. Other materials may include pulp, natural fibers such as linen, organic chemical fibers such as vinylon, ester, and rayon, or inorganic fibers such as glass fiber.

Paper making and filter element molding can be carried out using known equipment.

Next, the present invention will be explained using examples.

Example 1 Polyethylene terephthalate (PET) was used as the core component, and the ethylene content was 45 mol% and the degree of saponification was 99.5%.
With EVA as the sheath component, core component/sheath component = 70/30
(weight ratio), then stretched and cut to produce PET with a fineness of 1.5 dr and a fiber length of 5 mm.
A composite fiber consisting of EVA and EVA was obtained, and this was short-cut to obtain papermaking raw material. 70% by weight of this composite fiber and 30% by weight of pulp were mixed and dispersed at a concentration of 0.1% using PEO (manufactured by Steel Chemical Co., Ltd.) as a sticky agent and ZONDES KV (manufactured by Matsumoto Yushi Co., Ltd.) as a dispersant, and then used for ordinary short net paper making. The paper was mixed in a machine and passed through a dryer set at 140°C to obtain paper with a thickness of 0.5 mm.

This paper is pasted on both sides of the frame, and 12 of these filter elements are combined to form a filter.
A mixture of carbon black and heavy oil A was passed through this filter. At this time, the excess area is 5300cm ²
It was possible to process the carbon black at an overpressure of approximately 0.3 kg/cm ² up to approximately 400 g of carbon black adsorption.

On the other hand, the conventional mesh filter made of non-woven polyethylene fabric requires an overpressure of approximately 3.0 kg/cm ² and has an overarea of 9000 cm ² and an adsorption amount of carbon black of 200 g, making the filter of the present invention far superior. Excellent processing ability and oil resistance.

[Brief explanation of drawings]

FIG. 1 shows a schematic diagram of the filter element of the present invention. 1...Wet paper making for filters, 2...Mounting frame.

Claims (1)

[Scope of utility model registration request] Wet-processed paper containing 50% by weight or more of composite fibers made of a saponified ethylene/vinyl acetate copolymer with an ethylene content of 30 to 70 mol% and a degree of saponification of the vinyl acetate portion of 98 mol% or more and another thermoplastic polymer. A filter element made of paper obtained by the above-mentioned process, which is characterized by its excellent oil resistance.