JPH0782644A - Production of polyimide fibrous molded form - Google Patents

Abstract

PURPOSE:To form in high productivity a highly heat-resistant, stiff filter having backwashable cell structure by imparting wavy shape on nonwoven fabric or felt consisting of specific polyimide fibers through preheating, molding and cooling processes followed by cutting and jointing. CONSTITUTION:Nonwoven fabric or felt consisting of highly heatresistant polyimide fibers made up of recurring unit of the formula is introduced into a preheating chamber where said fabric or felt is preheated with a preheating caterpillar-type mold; the fabric or felt is then conveyed into a hot molding chamber where it is imparted, laterally or longitudinally, with wavy form periodically differing in height at regular intervals using a hot molding caterpillar-type mold, and then introduced into a cooling chamber where it is cooled with a cooling caterpillar-type mold; the resultant fabric or felt is cut to a specified dimension, thus obtaining the objective air-permeable wavy-surfaced polyimide fibrous molded form 0.5-1g/cm<2>. These molded forms are then mutually laminated to form a self-standing, stiff, wavy-surfaced filter of specified design. By the way, grooved rolls may be used in place of the above-mentioned respective caterpillar-type molds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a flame-retardant and highly heat-resistant air-permeable molded article made of an aromatic polyimide.

[0002]

2. Description of the Related Art A nonwoven fabric or felt made of highly heat resistant polyimide is heated at a temperature exceeding the glass transition point of the polyimide for an appropriate period of time, so that the shrinkage of the aromatic polyimide fiber and the mutual promotion of the fiber promoted by it. A method for forming a breathable molded body by fusion is disclosed in Japanese Patent Application Laid-Open No. 2-5033.
No. 33 publication. Although it is possible to mold a simple molded product such as a flat plate shape or a cylindrical shape using this technique, it is difficult to manufacture a filter having a surface corrugation that can stand on its own. Further, since a mold is used, a great deal of labor is required to attach the non-woven fabric or the felt, and it takes a long time for heating, heating and cooling, resulting in a high production cost.

[0003]

SUMMARY OF THE INVENTION The present invention solves the drawbacks of the prior art and provides a breathable molded article having the following characteristics:
An object of the present invention is to provide a method of manufacturing with low labor and high productivity. In other words, even large ones can be obtained, which can be made as thin and compact as possible, various mesh breathability is obtained, clogging is less likely to occur, long life, high heat resistance, and the desired shape of the molded product can be obtained. In addition, it has a large surface area, and has a cell structure capable of efficiently performing backwashing.

[0004]

The above-mentioned objects of the present invention are achieved by the method for producing a polyimide fiber molding of the present invention. That is, (1) a highly heat-resistant polyimide fiber having a repeating unit represented by the following general formula (1), having air permeability and a bulk density of 0.5 g / cm ^{3 to} 1 g / cm ^3.
In the method for producing a polyimide fiber molded body that is,
After molding the high heat-resistant polyimide fiber into a non-woven fabric or felt, the pre-heating consisting of a caterpillar mold or a grooved roll, each step of molding and cooling is passed through the non-woven fabric or felt in a horizontal or vertical direction to give a corrugation. Then, a method for producing a polyimide fiber molded body is characterized in that a corrugated non-woven fabric or felt is bonded to each other to produce a filter having a rigid surface corrugation that can be self-supporting.

[0005]

[Chemical 2]

(2) In the method for producing a polyimide fiber molded body which is corrugated in the horizontal direction or the vertical direction, backwashing is performed by periodically forming corrugations having different heights at regular intervals. It is possible to obtain a breathable polyimide fiber molded body having a cell structure capable of efficiently carrying out.

A specific example of a corrugated molding apparatus composed of a caterpillar mold suitable for realizing the steps of preheating, molding and cooling for molding the corrugated molded article of the present invention will be described below. However, the present invention is not limited to the specific examples described below. Further, in the corrugating apparatus of the present invention, the corrugating apparatus can be constituted by grooved rolls instead of the caterpillar mold for each of the steps of preheating, molding and cooling.

The waveform shaping device used in the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view of a waveform shaping device used in the present invention, and FIG. 2 is a plan view thereof. In FIG. 1 and FIG. 2, in the corrugating apparatus, the felt raw fabric 1 is sent out from the sending section to the preheating chamber 3, and then the heating forming chamber 4,
The process comprises cutting through the cutting chamber 9 through the cooling chamber 5. In the following, description will be given with reference to a side view of the apparatus of FIG. In FIG. 1, a pair of preheating caterpillar molds 6 and a heating molding chamber 4 facing the preheating chamber 3 are provided.
Is equipped with a pair of heat-molding caterpillar molds 7 facing each other, and a pair of cooling caterpillar molds 8 facing each other in the cooling chamber 5, respectively. It is fed between the preheating caterpillar molds 3 of 3 and preheated. The preheated felt 2 is then fed between the heat-molding caterpillar molds 7 of the heat-molding chamber 4 to be heat-molded into a wave shape, and then the cooling chamber 5
It is sent between the cooling caterpillar-type molds 8 to be cooled and set, and then discharged to the cutting table 9 and cut into a desired size. 1
Reference numeral 0 is a cut corrugated sintered body.

3 and 4 show a corrugating apparatus of the present invention constituted by a grooved roll. 3 is a side view of the corrugating apparatus having a grooved roll configuration, and FIG. 4 is a plan view thereof. In the corrugating apparatus constituted by the grooved rolls shown in FIGS. 3 and 4, the pair of preheating grooved rolls 11 facing the preheating chamber 3 and the pair of heating molding grooves facing the heating molding chamber 4. A pair of rolls 13 with cooling grooves facing each other are provided in the attached roll 12 and the cooling chamber 5, and the felt raw fabric 1 to the felt 2 of the sending-out portion are preheated in the same manner as in the case of the corrugated forming device of the caterpillar mold configuration. After being subjected to various steps of heat molding and cooling, it is formed into a corrugated shape, and it appears on the cutting table 9 and is cut into a desired size.

[0010]

The method for manufacturing a surface corrugated filter according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the examples described below.

Example 1 Draw ratio 1: 5 made from benzophenone-3,3 ', 4,4'-tetracarboxylic dianhydride and 4,4'-methylene-bis- (tolylene isocyanate), thick A needle felt 2 having a basis weight of 475 g / m ² , a thickness of 2.5 mm, and a width of 1,630 mm, which was preformed from a 30 μm-thick polyimide fiber by a needle punch method, was used as a sample. Using the corrugated forming device of the present invention composed of the caterpillar type mold shown in FIG. 1, from the felt 2 preformed by the needle punching method and wound on the felt raw fabric 1, the following air permeability is obtained. To produce a corrugated polyimide fiber molding having a surface corrugation.

The felt 2 sent out from the felt original fabric 1 was introduced into a preheating chamber 3 heated to 300 ° C. and preheated by a preheating caterpillar mold 6. The preheated felt 2 is then transferred to the heat forming chamber 4 held at 340 ° C., and the cross section of the heat forming caterpillar mold 7 is perpendicular to the traveling direction of the felt 2 at a height of 25 mm shown in FIG. Was formed. Then, it is introduced into the cooling chamber 5, cooled to 70 ° C. by the cooling caterpillar mold 8, and then, on the cutting table 9,
It was cut into 000 mm to form a corrugated polyimide fiber molding 14 having a corrugated surface. And cut 2
The molded products were adhered to obtain a self-supporting box-shaped box-shaped filter 15 having a height of 50 mm, a width of 1,000 mm, and a length of 1,500 mm shown in FIG. The chemical formula of the polyimide used in Example 1 is as shown in chemical formula I.

[0013]

[Chemical 3]

Example 2 A needle felt 2 preformed by the same needle punch method as that used in Example 1 was used as a sample. Using the corrugating device constituted by the grooved roll shown in FIG. 3 from the felt 2 preformed by the needle punching method and wound on the felt raw fabric 1, the surface corrugated having the following breathability is obtained. To produce the polyimide fiber molded article.

The felt 2 fed from the felt raw fabric 1 was introduced into the preheating chamber 3 in which the needle felt 2 was heated to about 300 ° C., and preheated by the preheating grooved roll 11. The preheated felt 2 is then transferred to the heat forming chamber 4 kept at 340 ° C., and the roll 12 with the heat forming groove changes the height of the wave for every three waves shown in FIG. 7 along the traveling direction of the felt 2. A 5 mm high corrugation was formed. Then, it was introduced into the cooling chamber 5, cooled to 70 ° C. by the roll 13 with the cooling groove, and then cut into 1,500 mm by the cutting table 9 to form the polyimide corrugated polyimide fiber molded body 16 having the air permeability. Then, the cut two molded bodies are stuck together and the height shown in FIG. 8 is 60 mm, the width is 1,000 mm, and the length is 1,5.
A box-shaped filter 17 having a cell structure of 00 mm having a corrugated surface that can be self-supported and capable of backwashing efficiently was obtained.

Example 3 A needle felt 2 preformed by the same needle punch method as that used in Example 1 was used as a sample. Example 1
The width of the needle felt 2 was 1,630 mm, but in the present Example 3, the width of the needle felt 2 was 800 m.
m. Using the corrugated forming device constituted by the grooved rolls shown in FIG. 3 from the felt 2 preformed by the needle punching method and wound on the felt original fabric 1, the wave height is 40 mm in the same manner as in the case of Example 2. A corrugated polyimide fiber molding having a corrugated surface was manufactured. However,
The molded body cut by the cutting table 9 has the length 10 shown in FIG.
It was a long polyimide fiber molded body 18 of m. Subsequently, both sides of the long polyimide fiber molded body 18 are joined to form a cylindrical shape, and a long cylindrical filter 19 having a diameter of 115 mm and a length of 10 m having eight corrugations shown in FIG.
Got

[0017]

EFFECTS OF THE INVENTION The method for producing a polyimide fiber molding of the present invention is highly heat resistant, has various air permeability, and has a smooth surface, so that it is difficult for the powder to adhere and the adhered powder can be easily peeled off. -It can be removed and has a long life with less clogging. Further, it is flame-retardant, and a non-woven fabric or felt made of aromatic polyimide fiber having excellent heat resistance is formed by a caterpillar mold or grooved rolls in which felts are arranged in tandem, preheating, forming and cooling the non-woven fabric or felt in each step. It has become possible to produce a self-supporting, rigid surface corrugated filter by corrugating it through the transverse or longitudinal direction and then joining the corrugated nonwovens or felts together. In addition, it is possible to obtain a long tubular filter having a surface corrugation which is rigid so as to be self-supporting by forming a tubular shape by joining both sides after corrugating the felt in a vertical direction.

[Brief description of drawings]

FIG. 1 is a side view of a corrugating apparatus of the present invention configured by a caterpillar mold.

FIG. 2 is a plan view of a corrugating apparatus of the present invention configured by a caterpillar mold.

FIG. 3 is a side view of the corrugating apparatus of the present invention configured by a grooved roll.

FIG. 4 is a plan view of the corrugating apparatus of the present invention configured by a grooved roll.

FIG. 5 is a perspective view showing a surface corrugated polyimide fiber molded body of the present invention.

FIG. 6 is a perspective view showing a surface corrugated box-shaped filter of the present invention produced by joining polyimide fiber molded bodies.

FIG. 7 is a perspective view showing a self-supporting surface corrugated polyimide fiber molding of the present invention.

FIG. 8 is a perspective view showing a box-shaped filter having a backwashable cell structure of the present invention.

FIG. 9 is a perspective view showing a long, self-supporting polyimide fiber molding of the present invention.

FIG. 10 is a perspective view showing a long tubular filter of the present invention.

[Explanation of symbols]

 1 Felt original fabric 2 Felt 3 Preheating chamber 4 Heating molding chamber 5 Cooling chamber 6 Preheating caterpillar mold 7 Heating molding Caterpillar mold 8 Cooling caterpillar mold 9 Cutting table 10 Sintered body 11 Preheating grooved roll 12 Heating molding Roll with groove 13 Roll with cooling groove 14 Polyimide fiber molded body 15 Box type filter 16 Polyimide fiber molded body 17 Box type filter 18 Long polyimide fiber molded body 19 Long cylindrical filter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location D06C 23/04 B

Claims (2)

[Claims] 1. A made of a high heat resistant polyimide fiber having a repeating unit represented by the following general formula (1), breathable, the bulk density of 0.5g / cm ³ ~1g / cm ³ Polyimide In a method for producing a fiber molded body, after molding the high heat-resistant polyimide fiber into a nonwoven fabric or felt, preheating consisting of a caterpillar mold or a grooved roll,
A filter having a corrugated surface that is self-sustainable by corrugating the nonwoven fabric or felt through the transverse or vertical direction in each step of molding and cooling and then joining the corrugated nonwoven fabric or felt to each other. A method for producing a polyimide fiber molded body, which comprises: [Chemical 1] 2. The method for producing a polyimide fiber molded body having a corrugation in the horizontal direction or the vertical direction, wherein corrugations having different heights are periodically formed at regular intervals. Manufacturing method of polyimide fiber molding.