JPH0681270A - Fiber composite and its production - Google Patents

Abstract

PURPOSE:To improve the performance of bag filter, precise filtration filter, seal gasket, electric insulating material and printed circuit board. CONSTITUTION:This fiber composite comprises polysulfone fibers and fluorine- polymer fibers. The fiber composite has excellent heat resistance, chemical resistance, dimensional stability, electric properties and filterability, and is readily producible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber composite having excellent heat resistance and chemical resistance and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, demand for dust collectors has increased from the standpoint of industrial sophistication or environmental improvement, but due to collection effects and maintenance, the dust collectors are shifting from electric dust collectors to bag filters. As a result, the demand for the development of fibers with excellent heat resistance and chemical resistance is increasing.

As fibers that meet such requirements, m-aramid fibers, polyphenylene sulfide (hereinafter referred to as PPS) fibers, and fibers made of fluorine-based resin are known. However, the m-aramid fiber has a problem of low chemical resistance and low versatility. In addition, PPS fibers are currently low in heat resistance and limited in their use range.
Fluorine-based fibers have high heat resistance and chemical resistance and are suitable fibers in that sense, but they have a problem in terms of physical properties that they have low strength. Further, since it is slippery, there is a problem that the strength of the fiber aggregate is further weakened. Further, when it is made of short fibers, there is a problem that the fibers easily fall off. Further, there is a problem that it is extremely expensive. Also, because it is difficult to manufacture ultrafine fluorine-based fibers,
There is a problem that the performance as a filter is lowered.

Although it is possible to eliminate such defects by compounding fluorine fibers with other fibers, conventional fibers have low chemical resistance and heat resistance, and fiber composites with fluorine fibers have been made. However, the overall physical properties of the fiber composite were low, and as a result, good products could not be produced. That is, it was not possible to produce a fiber assembly having good characteristics with only the fluorine-based fibers or even with a fiber composite composed of the fluorine-based fibers and other fibers.

[0005]

An object of the present invention is to provide a fiber composite suitable for spreading to various filters such as bag filters and electrical materials, and a method for producing the same.

[0006]

The above-mentioned object of the present invention can be achieved by a fiber composite comprising polyphenylene sulfone fibers and fluorine-based fibers.

The details will be described below. First, the fibers constituting the fiber composite in the present invention will be described. At least two types of fibers are used to form the fiber composite of the present invention.
The fibers of the present invention include not only so-called fibers but also processed products thereof such as woven and knitted fabrics, yarns, rovings, nonwoven fabrics and papers.

First, the polyphenylene sulfone (hereinafter referred to as PPSO) fiber which is a constituent fiber of the present invention will be described.

The PPSO fiber can be manufactured by a conventionally known method. For example, fibers obtained by the methods disclosed in JP-A-63-182413 and JP-A-63-225636 are particularly preferable. Further, a special PPSO fiber or the like disclosed in JP-A-2-175920, in which the sea or sheath component is made of PPSO and the island or core component is made of liquid crystal polymer, is also a preferable fiber. The fineness can be appropriately selected according to the use, but when the use of the fiber composite of the present invention is a filter, it is preferable that the fiber contains 5 denier or less, particularly preferably 2 denier or less. Then, in the case of a filter having particularly high performance, it is preferable that ultrafine PPSO fibers having a denier of 1 or less are contained in the fiber composite.

The length of the PPSO fiber of the present invention is not particularly limited, but when the fiber composite of the present invention is used as a non-woven fabric or the like, if it is too short, it tends to fall off from the composite. Therefore, it is preferably 20 mm or more.

When the fiber composite of the present invention is used as paper, it may have a shorter length of 0.5-.
The one with 5.0 mm is adopted.

The fiber composite of the present invention essentially contains such PPSO fibers and fluorine-based fibers. Next, the fluorine-based fiber which is another fiber in the present invention will be described. Examples of the fluorine-based fiber include a fiber made of polytetrafluoroethylene (hereinafter referred to as PTFE), a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, a tetrafluoroethylene / hexafluoropropylene copolymer,
Any fiber such as a fiber made of a resin such as tetrafluoroethylene / ethylene copolymer can be used.
A particularly preferable fluorine-based fiber is a fiber made of PTFE. The PTFE fiber is preferable because it has both high heat resistance and chemical resistance and is inexpensive.

As the fiber, the fiber obtained by a conventionally known method can be applied. The fineness can be appropriately determined according to the application, but when the application is a filter, it is preferably a fluorine fiber having a denier of 5 or less.

If the length of the fluorine-containing fiber of the present invention is too short, it tends to fall off from the fiber composite. Therefore, when the fiber composite of the present invention is used as a non-woven fabric or the like, it should be 10 mm or more. Is preferred. In addition, when the fiber composite of the present invention is used as paper, it is even shorter.
It may be made of a fluorine fiber having a length of 5 to 5 mm.

The fluorinated fiber of the present invention may be composed of one kind of fluorinated fiber or may be composed of several kinds of fluorinated fiber. Further, the fineness of the constituent fibers is not particularly limited and may be denier mixed.

Next, the PPSO fiber and the fluorine-based fiber in the fiber composite will be described. The ratio of the two is not particularly limited, but from the viewpoint of strength, filtration performance, electrical characteristics, etc. of the fiber composite, the weight ratio is preferably PPSO fiber / fluorine fiber = 10 to 90/90 to 10.

Especially when the fiber composite is used as a filter having high filtration performance, it is preferable that the ratio of the PPSO fibers composed of fine fibers is high, and the weight ratio of PPSO fibers / fluorine-based fibers = 40-90 / 60-. It is preferably 10. Next, the distribution state of both fibers in the fiber composite can be appropriately determined depending on the application. For example, when used as a bag filter, it is also effective to increase the composite ratio of PPSO fibers on one side of the fiber composite and increase the composite ratio of fluorine-based fibers on the other side. Particularly in the case of deep layer filtration, it is an effective method to remove coarse dust with a layer having a large proportion of fluorine-based fibers composed of thick fibers, and then performing microfiltration with a layer having a large proportion of PPSO fibers composed of thin fibers. is there. If such a configuration is adopted, the filtering effect is high, and dust can be quickly removed.

PP is formed on both sides of the woven fabric made of fluorine fibers.
It may be a composite of SO fibers and needle punched. The yarn used for needle punching is made of fluorine fiber and P
It may be a mixture of PSO fibers.

When the fiber composite of the present invention is used as an electric material, a sheet in which PPSO fibers and fluorine-based fibers are uniformly mixed and the ratio of fluorine-based fibers is increased to provide excellent heat resistance. It is preferable because a sheet having a low dielectric constant can be produced.

Further, in particular, when the fiber composite of the present invention is used as a filter for filtering a chemical solution, the PPSO fiber is rich in hydrophilicity, so that the penetration of the chemical solution is excellent and dust can be easily removed, which is preferable.

The fiber composite of the present invention is particularly preferably that the PPSO fiber and the fluorine-based fiber are fused.

It is not necessary that all the fibers constituting the present invention are fused, but if some of the fibers are fused, separation of the fibers from the fiber composite can be reduced.

Next, a method for producing the fiber composite of the present invention will be described. First, a PPS fiber and / or a polyphenylene sulfide sulfone (referred to as PPSS) fiber and a fluorine-based fiber or a processed product thereof are compounded to form a composite composed of at least two-component fibers.

The PPS fiber or PPSS fiber can be produced by a conventionally known method, but the ultrafine PPS fiber or the ultrafine PPSS fiber can be produced by, for example, PPS and other resins as described in Japanese Patent Publication No. 50-13849. Is polymerized as a polymer array fiber, and the polymer array fiber is compounded as it is with a fluorine-based fiber, and then the other resin is removed to produce a composite of ultrafine PPS fiber and fluorine-based fiber. be able to. The fiber composite may be obtained by removing the other resin from the polymer array fiber to form an ultrafine PPS fiber, and then composite with a fluorine-based fiber. Also, a felt in which both fibers are compounded may be obtained by laminating PPS fibers or PPSS fibers on one side or both sides of a fluorinated fiber woven fabric and needle punching.

In the present invention, the composite thus obtained is treated with an organic peroxide. Typical organic peroxides are peracetic acid, perbutyric acid, and perpropionic acid.

The time for treating the composite with such an organic peroxide varies greatly depending on the fineness of the PPS fiber or PPSS fiber, and the type, temperature, and concentration of the organic peroxide. There is a need.

The specific method of treatment is also not particularly limited. For example, a method of rolling the composite in a roll shape, immersing the composite in a bath of organic peroxide, and performing batch treatment,
A method in which the composite is continuously fed into a bath of organic peroxide and continuously treated can be preferably adopted.

By this treatment, PPS fiber and PPSS
The fiber composite of the present invention can be obtained by modifying the fibers into PPSO fibers and then optionally removing the organic peroxide.

When it is required that the fiber composite of the present invention has particularly high dimensional stability and is resistant to falling off, the PPSO fiber and the fluorine-based fiber can be fused by heat. . That is, the fiber composite is heat-treated to fuse the fluorine-based fiber and the PPSO fiber. The heat treatment temperature can be appropriately set according to the melting point of the fluorine-based fibers constituting the fiber composite, and the fusion heat treatment can be performed.

The heat treatment can be carried out by holding the fiber composite with a conveyor belt, a pin tenter, a clip tenter or the like in a heated atmosphere. Further, the heat treatment can be performed with a heating roll or a hot press.

By this treatment, the PPSO fiber and the fluorine-based fiber are fused and formed into a fiber composite having stable characteristics.

The fiber composite of the present invention has heat resistance, chemical resistance, good electrical properties, slipperiness and non-adhesiveness, and
Since it retains hydrophilicity and hydrophobicity at the same time, it can be used for various purposes.

The typical application will be illustrated. Bag filters, chemical filters, food filters, mold release materials, battery separators, heart patches, artificial blood vessels, artificial skin, printed circuit board substrates, electrical insulation materials, learning materials, industrial felts, engine oil filters, wiping cloths. ,
Wind stabilizer, copy cleaner, insulation,
Gaskets, safety clothes, lab clothes, waterproof materials, demisters, dryer canvases, ion exchange base materials, etc.

[0034]

The present invention will be described in more detail with reference to the following examples.

Example 1 3 denier PPS fiber and 5 denier PTFE fiber were mixed so that the former was 75% by weight and the latter was 25% by weight, passed through a card cloth wrapper, and needle punched, The felt had a basis weight of about 450 g / m ² .
Next, wind the felt on a stainless steel tube with a hole, and 2
The PPS fiber in the felt was modified into PPSO fiber by immersing in 0% peracetic acid solution, flowing the peracetic acid solution from the inside of the cylinder to the outside, and treating the rolled felt.

This sheet is a sheet that withstands heat of 300 ° C., withstands nitric acid mist, has excellent filtering performance, and has excellent dust drop properties, and is a good bag filter base material. It was something.

Example 2 5 denier PTFE fiber and 2 denier PPSO fiber were mixed so that the former amount was 20% by weight and the latter amount was 80% by weight, passed through a card cloth wrapper, and needle punched, The felt had a basis weight of about 400 g / m ² .

Next, the felt was passed through a roll heated to 330 ° C. and hot-pressed.
A felt having PSO fibers fused was obtained.

This sheet has excellent dimensional stability, and
The heat resistance and chemical resistance were good, and the constituent fibers did not fall off.

Example 3 A polymer array type base having 16 islands was used, and island component / sea component = PPS / polystyrene = 70/30 (weight ratio).
And further drawn 3.5 times to obtain 5 denier fibers. The fiber was crimped and then cut into 51 mm cotton.

Next, the cotton and 5 denier PTFE fiber were mixed so that the former amount was 85% by weight and the latter amount was 15% by weight, passed through a card cloth wrapper, and needle punched to give a basis weight. The felt was 460 g / m ² .
Next, the felt was washed with trichlene to remove polystyrene as a sea component. The felt after the removal treatment was used in Example 1.
Treat the PPS fiber in the felt with PPSO
Denatured into fibers. This sheet can withstand the heat of 300 ℃,
Further, it is a sheet having resistance to nitric acid mist and hydrofluoric acid, and having excellent filtering performance and dust drop-off property, and is suitable as a filter substrate for precision industry.

Example 4 The 5 denier fiber of Example 3 was cut into 3 mm, washed with trichlene to remove sea components, and 3 mm of ultrafine PPS.
Fiber was obtained. Next, the fibers were immersed in a 20% peracetic acid solution to obtain ultrafine PPSO fibers.

Next, 2 denier PTFE fiber and the ultrafine PPSO fiber were used in the former 75% by weight and the latter 25% by weight.
Was adjusted so as to obtain paper, and a paper-making material having a thickness of 2 mm was obtained. Next, when the paper-like material was treated with a hot roll heated to 325 ° C., a paper-like material having a thickness of 0.7 mm was obtained. Further, the 2-denier PTFE fiber and the ultrafine PPSO fiber were partially fused, and the dimensional stability was excellent, and the fibers did not drop off from the paper-like material. The paper-like material was effective as a microfiltration filter, an electric insulating material, and a printed circuit board.

[0044]

EFFECTS OF THE INVENTION A fiber composite having good heat resistance, chemical resistance, dimensional stability, electrical characteristics, and filtration performance, and those fiber composites can be easily produced.

Since the fiber of the present invention has such characteristics, it may be possible to improve the performance of an efficient bag filter, precision filtration filter, high-performance seal gasket, electrical insulating material, printed circuit board and the like. it can.

Claims (4)

[Claims] 1. A fiber composite comprising polyphenylene sulfone fibers and fluorine-based fibers. 2. A fiber composite, wherein the fluorine-based fiber is made of polytetrafluoroethylene, and the fluorine-based fiber and the polyphenylene sulfone fiber are fused. 3. The fiber composite according to claim 1, wherein the polyphenylene sulfone fiber is an ultrafine fiber having a denier of less than 1 denier. 4. A polyphenylene sulfide fiber and / or a polyphenylene sulfide sulfone fiber and a fiber-fluorine-based fiber are composited to form a composite of at least two kinds of fibers, and the composite is treated with an organic peroxide to form a composite. A method for producing a fiber composite, characterized in that the constituent polyphenylene sulfide fiber and / or the polyphenylene sulfide sulfone fiber is a polyphenylene sulfone fiber.