JPH03275109A - Filter base material - Google Patents

Abstract

PURPOSE:To obtain the filter base material easy to produce and excellent in physical properties by injecting a gas into a viscous polyarylene sulfide (PAS) to blow off the PAS and using the product PAS short fiber. CONSTITUTION:A gas is injected into a viscous PAS to blow off the PAS, and the product PAS short fiber is used to obtain a filter base material. A mat material obtained by combining the short fiber with a carbide short fiber is used when mechanical strength is required. The PAS short fiber is heat- treated at a temp. above the glass transition temp. of PAS at an optional stage between the production of the PAS short fiber and the production of the filter base material. The molten PAS flows at 500-3000g/10min. Since the filter base material is produced from the PAS fiber excellent in resistance to heat and chemicals, the base material is more easily produced than before, and the physical properties are excellent.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a polyarylene sulfide resin in a viscous state (
Hereinafter, it will be abbreviated as P'AS. ), and relates to a filter base material made of PAS short fibers obtained by injecting gas and blowing it away.

[Prior art]

It is known that PAS, particularly polyphenylene sulfide resin (hereinafter abbreviated as PPS), which is a typical PAS, is made into fibers and used as a filter base material. For example, Japanese Patent Publication No. 52-30609 discloses a filter base material made of a woven fabric made from filaments that are spun and drawn by a melt spinning method and then made from the filaments. In addition, nonwoven fabrics made by melt-spinning and stretching PPS, then crimped, then cut, carded, and then subjected to treatments such as needle punching, or nonwoven fabrics that were subjected to treatments such as needle punching after spinning (spunbond method). etc. are also known as filter base materials.

[Problem to be solved by the invention]

However, in either case, the polymer used for spinning has a melt viscosity of at least 1.000 voids or more depending on the spinning technology.
High molecular weight polymers were always used because of the need to increase the temperature. However, PPS has a relatively high melting point;
For this reason, spinning conditions must be set at fairly high temperatures, but under such harsh conditions, polymer decomposition, gas generation, and gelation are likely to occur, which can also cause nozzle clogging, making stable spinning difficult. there were.

Another disadvantage is that various steps such as crimping, cutting, and carding of the fibers are usually required before a filter base material is obtained from the PAS fibers. Moreover,
In the case of filter base materials obtained through conventional processes,
Poor recovery after filter use, so-called "settling"
It also failed to resolve its perceived shortcomings.

In this way, filter base materials made using PAS fibers made by conventional methods require many steps, and the raw material PAS has a high melt viscosity that cannot be used for general-purpose injection molding. It requires a molecular weight polymer, which poses various problems in the spinning process, and also has drawbacks in its filter properties.

An object of the present invention is to provide a filter that is inexpensive and has good physical properties using PAS fibers that have excellent heat resistance and chemical resistance.

[Means to solve the problem]

The present inventors have completed the present invention as a result of intensive research to solve the above problems.

That is, the present invention relates to a filter base material using polyarylene sulfide short fibers obtained by injecting gas into viscous polyarylene sulfide and blowing it away.

In the present invention, the means for forming PAS into fibers is different from the usual spinning method, and involves injecting and blowing gas into viscous PAS. This spinning method is a method of efficiently stretching the molten PAS yarn discharged from a nozzle by blowing gas, preferably at a temperature of about 250°C to 350°C, which is about the same as the spinning temperature. By changing the discharge pressure, gas temperature, jetting angle, flow rate, etc., the average fiber diameter can be changed from several μm to several tens of μm, and the average fiber length is 5 μm.
Fiberization of ~300 tm is possible. Among the fiberization means based on the gas injection law, in particular, the injected gas has a tangential component appearing on the outer periphery of the cross section perpendicular to the central axis of the molten PAS, and along the progress of the molten PAS. The gas has components that first gradually approach the central axis and then gradually move away from the central axis, and this gas is brought into contact with the outflowing molten PAS, using the so-called "eddy current method" (Special Publications Show). (Refer to Publication No. 58-57374)
gives curled PAS short fibers. These curled short fibers are delicately intertwined with each other, making it easy to maintain the shape of the filter base material, and also having excellent recovery properties after the filter is actually used. Furthermore, the physical properties of the fibers are good, with a tensile strength of 30 to 70 kg/cm, so their use is suitable.

The fibers made into fibers by the above means are collected and deposited on a horizontally moving mesobelt or the like under negative pressure, and then passed through, for example, a fixed roll to form a relatively dense pine I-shaped fiber. Formed as fiber (RAS raw cotton mantle).

By adjusting the speed of the mesh conveyor, the thickness of the cloak-like fiber can be adjusted, and the obtained cloak-like fiber can be used as it is as a filter base material, so it is very easy to prepare the filter base material. It is.

As the PAS short fibers used in the filter base material according to the present invention, the form of the PAS raw cotton mantle obtained by the above-mentioned fiberization method can be used as is, or the raw cotton mantle can be needle-punched singly or laminated with several sheets to make it high. It can also be used in the form of a uniform non-woven fabric made by densification, or one in which the raw cotton is sprayed with a suitable bangu.

Furthermore, since the PAS short fibers spun by gas injection reach the belt conveyor within a short time, they sometimes form raw cotton mats without being sufficiently heat-treated. Since thermal stability may not necessarily be sufficient depending on the application, heat treatment is useful. The temperature at that time is preferably higher than the glass transition temperature of the PAS to be made into fibers.

As a heat treatment method, the short fibers or mantle may be inserted as they are into a heat treatment furnace, but in order to prevent the ultimate elongation of the PAS short fibers from becoming small and the tensile strength from decreasing, It is more desirable to heat-treat the PAS short fibers in a state that minimizes the shrinkage of the fibers, that is, under a constant length. As a method under such a fixed length, for example, a large number of needle-like objects embedded at high density,
Alternatively, the mat may be fixed by pressing down the cloak with a roller or by suction, but the method is not limited to these methods. The mat obtained by the above operation may be used as it is, or it may be opened to form a web and then made into a non-woven fabric by a suitable method such as needle punching. Further, the heat treatment may be carried out after shaping the cloak or nonwoven fabric into a shape to be actually used, and the temperature and other conditions at that time are similar to those described above.

PAS, which is the raw material for the filter base material according to the present invention, is
Structural formula (-Ar-3-), 1 (Ar: arylene group)
It is a polymer represented by Here, -A of the arylene group
r- is p-phenylene, m-phenylene, 0-phenylene, 2.6-naphthalene, 414'biphenylene, etc., or a divalent aromatic ring residue containing two 6-carbon aromatic rings, and , each aromatic ring has F, Cj! , Br+C
Substituents such as H3 may also be introduced. these are,
It may be a homopolymer, a random copolymer, or a block copolymer.

In particular, it is preferable to use linear PAS which has a relatively low viscosity.

Such PAS is based on ASTM D-1238-70, and in the case of crystalline resin, the temperature conditions are set to melting point +30°C,
In the case of amorphous resin, the melt flow value measured with the glass transition temperature + 100 °C and a load of 5 kg is 500.
~3000.

In addition, among the above-mentioned PAS, the PPs detailed below
, polyphenylene sulfide ketone resin (hereinafter referred to as PP5)
Furthermore, block copolymers consisting of a PP, S moiety and a polyphenylene sulfide sulfone (hereinafter abbreviated as ppss) moiety have excellent physical properties and are suitable for use.

PPS is a polymer containing 90 mol% or more of the structural formula. PPS is 100 (R: any one of alkyl, phenyl, alkoxy, nitro, or halogen group). Some of these structural components are formed during the polymer synthesis process or post-treatment process.

Such PPS can be produced by common methods such as (1) reaction of a halogen-substituted aromatic compound with an alkali sulfide (see U.S. Pat. No. 2,513,188, Japanese Patent Publication No. 4427671 and Japanese Patent Publication No. 45-3368); (2) thio Condensation reaction of phenols in the coexistence of an alkali catalyst or copper salt, etc. (US Patent No. 3,274,165, British Patent No. 11,606)
60) (3) Condensation reaction of aromatic compounds with sulfur chloride in the presence of a Lewis acid catalyst (Japanese Patent Publication No. 46-2725
No. 5, Hergie Patent No. 29437), etc., and can be arbitrarily selected depending on the purpose.

1 In the case of PPS used in the present invention, its melt flow (
316°C, 5kg load) is 7oo to 3oo.

8710 minutes, preferably in the range of 1000 to 20008710 minutes.

PP5 is a highly heat-resistant resin whose main constituent is a repeating unit (in the formula, the -CO- group and -3- group are bonded to the hala position via a Hensen ring). In order to have high heat resistance, it is preferable that the content of the repeating unit as a main constituent exceeds 50% by weight, more preferably 60% by weight or more. If the content of the repeating unit is 50% by weight or less, the crystallinity of the resin may decrease, and the heat resistance may also decrease accordingly. Different types of repeating units other than the above-mentioned repeating units include (excluding those in which -CO- and -3- groups are bonded to the hala position through the Hensen ring) 2. The lower alkyl group, m is O to 4. (integer), etc.

The melt flow to PP5 (390℃, 5kg load) is:
500-3000g/10 minutes, preferably 700-15
It is in the range of 00 g/10 minutes.

In addition, there is a professional (PPS) consisting of a PPS part and a PP5S part.
) as a repeating unit and a block copolymer consisting of a polymer part as a repeating unit, disclosed in JP-A-62-
It can be obtained by the manufacturing method disclosed in JP-A No. 115030, JP-A-63278935, and the like. For example, PP5S with a terminal chlorphenyl group obtained by reacting sodium sulfide and bis(p-chlorophenyl)sulfone in N-methylpyrrolidone, and sodium sulfide and p-chlorphenyl
-dichlorobenzene in N-methylpyrrolidone and heating terminal sodium sulfide group type PPS3 4 in N-methylpyrrolidone.

The proportion of ppss moieties in the block copolymer is 10
The range is 99 mol%, preferably 30 to 70 mol%.

In addition, the block copolymer contains P that may be contained during production.
A homopolymer of PS, a homopolymer of PP5S, and a random copolymer of phenylene sulfide sulfone and phenylene sulfide may be included as long as they do not impair the effects of the present invention.

Melt flow of such a block copolymer (316 °C, 5
kg load) is in the range of 500 to 3000 g/10 minutes, preferably 700 to 1500 g/10 minutes.

The filter base material according to the present invention uses a mat-like material of PAS short fibers made into fibers by gas injection, as well as
Particularly in applications where mechanical strength is required, it is desirable to use a cloak-like material in which the short fibers are combined with short carbonized fibers.

The short carbonized fibers have an aspect ratio of 50 or more,
Preferably 200 to 1500 carbon fibers are used.

The form of the cloak-like product may be PAS short fibers as they are, PAS raw cotton cloaks opened and then mixed with carbonized short fibers, or needle-punched non-woven fabrics, or PAS raw cotton mats and mat-like materials. PAS is made by needle-punching a layered layer of carbon fiber.
Carbon fiber laminated nonwoven fabric is preferred. Heat treatment is applied to the cloak,
Alternatively, it may be applied to the nonwoven fabric as it is, or it may be applied after shaping the bottom into the shape to be actually used.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Based on STM D-1238-70, temperature 316°C
, melt flow 1300g/measured under a load of 5kg.
PPS for 10 minutes was spun using the eddy current method, and the fiber length was 80 to 150 cm, the bulk density was about 0.01 g/cIn3, and the apparent thickness was about 2 On+.
The air permeation rate measured with a Gurley densometer is 36
000 (cm2/sec-atm) was obtained.

This is designated as MAT-1.

Example 2 A load of 5 g/am2 was applied to MAT-1, and this was
The cloak was left for 5 minutes in a constant temperature bath kept at 0.degree. C., and the resulting heat-treated cloak was designated as MAT-2.

The bulk density of MAT-2 is approximately 0.2 g/ω3, and the air permeation density measured with a Gurley densometer is 200 (c+n2/
sec-atm), and the apparent thickness was about 111.

Example 3 MAT-1 was punched to a needle depth of 20 tm using a needle punch machine.
By needle punching at a needle density of 120 needles/cflI2 and 400 strokes per minute, a fabric weight of 600 was obtained.
g/m2, with an apparent thickness of 7 inches, and
It is called AT-3. The bulk density of MAT-3 is 0.03g/c
The air permeation rate measured with an m3 Gurley densometer was 10,000 (Cm''/sec-atm).

In addition, this MAT-3 was attached to the exhaust duct and used for one month. The wind speed at the center of the exhaust duct is approximately 1 m/sec.
Met. The thickness of MAT-3 after use was measured and was 6u.

Comparative Example 1 Based on ^STM D-1238-70, temperature 316°C
, melt flow 300 g/1 measured under the condition of 5 kg load.
0 minute PPS was spun by a normal melt spinning method to obtain a single PPS fiber with a diameter of 28 μm.

This was made into a nonwoven fabric with an apparent thickness of 7 m and a weight of 600 g/m using the same spunbond method as in Example 3. However, in order to have the same bulk density as MAT-3 (0.03 g/cm''), it had to be treated to have an average shrinkage of 30 peaks/inch.

This nonwoven fabric was attached to an exhaust duct in the same manner as MAT-3 in Example 3, and used for one month. The apparent thickness after use was measured to be 4 fl.

Example 4 78 MAT-3 was loaded with 5 g/cm2 and 19
The felt was left in a constant temperature bath kept at 0° C. for 3 minutes, and the resulting felt was designated as MAT-4. The properties of MAT-4 are that the apparent thickness is approximately LNN, the bulk density is 0.58/cm", and the air permeation rate measured with a Gurley densometer is 150 (cm2/s).
ec-atm).

Example 5 After opening MAT-2 using a card machine, needle bunching was performed in the same manner as in Example 3 to obtain a fabric weight of 750 g/m.
The nonwoven fabric of No. 2 is referred to as MAT-5.

The properties of MAT-5 include a bulk density of 0.04 g/cm3 and an air permeation rate of 7.000 as measured by a Gurley densometer.
(cm2/sec-atm) Example 6 A resol type phenolic resin (“Pryophen” manufactured by Dainippon Ink and Chemicals Co., Ltd.) was diluted so that the nonvolatile content was about 8 wt%, and it was diluted with MAT5. It was evenly distributed on both sides by spraying and then impregnated by rolling. The ratio of resin solid content to nonwoven fabric weight is 0
．． 35 times, and the basis weight was 900 g/m''. After impregnation, the felt was dried at 110°C for 3 minutes.
-6. The properties of MAT-6 are bulk density 0.06g/c
The air permeation rate measured by m' Gurley densometer was 5,000 (cfn''/sec-atm).

Example 7 After opening MAT-2, carbon fiber Dona Carbo ■5210
(pitch-based carbon fiber, manufactured by Tonatsuku Co., Ltd.) and needle bunched to give a basis weight of 600 g/m3 in the same manner as in Example 3 to obtain a nonwoven fabric. This will be referred to as MAT-7.

The properties of this material include a bulk density of 0.05 g/cm' and an air permeation rate of 8000 (cm2) measured with a Gurley densometer.
/sec-atm).

Example 8 Based on ASTM D-1238-70, temperature 316°C
The melt flow measured under the condition of 1 load of 5 kg was 540 g/
A block copolymer (containing 40 mol% of PPSS) consisting of a 10-minute PPS part and a PPSS part was spun by the eddy current method, and this was directly received on a helt conveyor to obtain a fiber length of 50 ~], 30 ms, and a bulk density of Approximately 0. O], g9 0 70m3, apparent thickness is approximately 2011, air permeation rate measured with Gurley densometer is 40000 (cm2/
sec-atm) was obtained.

Example 9 Based on ASTM 04238-70 method, temperature 390'
C, the melt flow measured under the condition of 5 kg load is ↓500
g/10 minutes of polyphenylene sulfide ketone was spun by a vortex method, and this was directly received on a helt conveyor,
Fiber length 60-1.50 W, bulk density approximately 0. O1g/c
m3 apparent thickness is approximately 2011, Gurley densometer
The air permeation rate measured at 38,000 (cm215e
ca tm) mat was obtained.

〔Effect of the invention〕

The filter base material of the present invention, which uses PAS short fibers made into fibers by gas injection, is easier to manufacture than conventional filter base materials and has good physical properties.

Claims (4)

[Claims] 1. A filter base material made of polyarylene sulfide short fibers obtained by injecting gas into viscous polyarylene sulfide and blowing it away. 2. A filter base material made of a fiber composition comprising short polyarylene sulfide fibers and short carbon fibers obtained by injecting gas into viscous polyarylene sulfide and blowing it away. 3. A claim in which polyarylene sulfide short fibers are used as the filter base material, which have been heat-treated at a temperature equal to or higher than the glass transition temperature of the polyarylene sulfide at any stage from after producing the polyarylene sulfide staple fibers to producing the filter base material. The filter base material according to Items 1 and 2. 4. Melt flow of polyarylene sulfide is 500~3
000g/10min (according to ASTM D-1238-70, temperature conditions are set to melting point + 30℃ for crystalline resin, glass transition temperature + 100℃ for amorphous resin, load 5kg)
) The filter base material according to any one of claims 1 to 3, wherein the filter base material is in the range of: