JP2530636B2 - Special paper sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a special paper-like sheet. More specifically, it relates to a special paper-like sheet which is particularly excellent in water resistance, heat resistance, oil resistance, flame retardancy, radiation resistance and the like.

[Conventional technology]

In recent years, paper-like sheet materials are not limited to conventional applications such as recording paper, shoji paper, and wrapping paper, but are extremely widespread and have begun to expand to various fields. Its representative fields are widely applied to electric fields such as capacitors, and various filter papers.

The main properties required for paper in these fields are heat resistance,
Compatibility of strength and flexibility, water resistance, little falling off from paper-like sheets, especially less falling off from paper-like sheets even after repeated fatigue to some extent, oil resistance, flame retardancy Sex, etc.

Various methods have been disclosed for imparting such characteristics.
Typical examples are as follows.

That is, since the sheet-like material disclosed in Japanese Examined Patent Publication No. 57-24440 is mainly composed of a high heat-resistant organic material and an inorganic material, it is somewhat brittle and has a problem that the inorganic material easily falls off. ， It is something that is not enough to expand into the so-called high-tech field.

The sheet-like material disclosed in Japanese Examined Patent Publication No. 57-400 relates to gypsum paper mainly composed of natural pulp and gypsum. Gypsum paper certainly has high heat resistance, but in particular,
There is a major drawback that it is difficult to achieve both strength and flexibility, which are characteristics of paper.

Although a method for producing a non-woven fabric composed of polyphenylene sulfide and heat resistant fibers is disclosed in Japanese Patent Laid-Open No. 61-289162, the polyphenylene sulfide fibers used in this publication must be undrawn fibers. . Unstretched fibers have the advantage that they can be fused at low temperatures, but
On the contrary, there is a big defect that the heat resistance at high temperature is poor. If not stretched to some extent, the fibers are extremely weak. Particularly, those having an aromatic ring in the molecule, such as polyphenylene sulfide or polyethylene terephthalate, and having no hydrogen bond or ionic bond between the molecules, exhibit the original characteristics of the polymer only by stretching. Therefore, especially once exposed to high temperature, it becomes extremely brittle, and especially when repeatedly fatigued, it easily breaks and does not maintain a fibrous form. Further, the unstretched fiber has a drawback that the shrinkage rate is extremely high. Therefore, even if such a fiber is used as an adhesive for a sheet, the adhesive action of the sheet is lost especially at high temperatures, and in addition, the fiber itself comes off from the sheet. Further, if the processing conditions are not extremely limited, a serious problem such as deformation of the sheet during the processing occurs.

The object of this publication is a so-called non-woven fabric, not a paper-like sheet.

In other words, these paper-like special sheet materials have progressed as compared with conventional papers made of cellulose, but they have the following major problems for further widespread development.

 That is, the heat resistance is poor.

Poor water resistance. Particularly, the high temperature water resistance is poor.

Both strength and flexibility are incompatible.

There are many objects that have fallen out of the paper sheet. Especially when repeated fatigue tests are performed, the amount of lost objects increases significantly.

Low oil resistance.

Low flame retardancy.

Low radiation resistance.

[Problems to be solved by the invention]

That is, the problems solved by the present invention are as follows.

That is, low heat resistance, low water resistance, incompatibility between strength and flexibility, low oil resistance, low flame retardancy, low radiation resistance, and many falling off items from paper.

[Means for solving problems]

In view of the present situation, the present inventor arrived at the present invention as a result of earnest studies, without being bound by the conventional research concept. The present invention has the following configuration in order to solve the problem.

(1) A special paper-like sheet, which comprises at least a fiber made of an aromatic ring polymer having a melting point of 300 ° C. or higher selected from poly-phenylene-phthalamide, polybenzobisoxazole, and polybenzobisthiazole,
Special which is less than 0.3 denier and contains a polyarylene fiber of the following structural formula mainly composed of short fibers, wherein the fiber composed of the aromatic ring-containing polymer and the polyarylene fiber are bonded or welded Paper sheet.

(2) A polymer forming a paper, wherein an acidic group is added to the aryl group of the polymer.
The special paper-like sheet described in paragraph.

(3) The special paper-like sheet according to claim 1, which is obtained by adding a diphenyl ether derivative to a polyarylene fiber.

 This will be described in more detail below.

According to the present invention, it is extremely surprising that a paper-like special sheet material having epoch-making strong chemical resistance and high water resistance can be produced.

The special sheet material of the present invention comprises at least a binary polymer, one of which is a polyarylene fiber represented by the following structural formula.

The one represented by this structural formula is hereinafter referred to as PAS. A typical one is polyphenylene sulfide fiber, and a particularly preferable one is a polymer in which poly-P-phenylene sulfide (hereinafter referred to as PPS) is a main constituent unit.
Such a product has a great advantage of being extremely rich in chemical resistance and heat resistance.

Specific examples thereof include PPS, poly-P-phenylene sulfoxide, poly-P-phenylene sulfone, copolymers thereof, and modified products thereof.

Needless to say, various additives may be added to the polymer. When the radiation resistance is particularly high, diphenyl ether derivatives (diphenyl ether having various alkyl groups, aromatic rings having a large number of ether bonds, and aromatic rings having a large number of ether bonds) are used. It is also particularly preferable to add an alkyl group, an aromatic ring-bonded product, etc.) to the bonded product.

In addition, PAS fibers made of a polymer in which a sulfonic acid group, a carboxylic acid group, etc. are added to the aryl group are also particularly hydrophilic, which makes them easy to wet papermaking, and easy to color and decolorize easily. Etc. are particularly preferable.

A conventionally known method can be applied to the method for producing such a polymer, and the method is not particularly limited. Further, in order to improve the functionality of the special paper-like sheet of the present invention, a conventionally known method can be applied to add a sulfonic acid group or the like to a phenyl group,
There is no restriction. Particularly preferred methods for addition of sulfonic acid groups are, for example, sulfur trioxide treatment of fibers, fuming sulfuric acid treatment, sulfuric acid treatment, chlorosulfonic acid treatment, combined treatment of carbon tetrachloride and chlorosulfonic acid, and the like. It is also an extremely effective method to add PPS fibers to sulfonic acid-containing fiber by adding acid groups. It is also extremely effective to add a sulfonic acid group to the monomer and copolymerize the monomer with a monomer to which a sulfonic acid group has not been added.

A particularly preferable method for adding a sulfonic acid group or the like to PAS fiber is to carry out the treatment after forming the fiber, and especially after forming the ultrafine fiber or multi-surface fiber such as multi-hollow fiber (lotus root fiber). is there. If such a method is adopted, the reaction time can be shortened, and since it can be carried out at a relatively low temperature, it has a great merit that side reactions are few and can be completed completely and safely. Needless to say, the present invention is not limited to this method.

The component of the special paper-like sheet of the present invention is composed of at least such a polymer, but is composed of such a polymer.
PAS fibers are mainly 0.3 denier (hereinafter referred to as d) or less.

If it exceeds 0.3d, the sheet-like material is hardened, the flexibility is lost, and the sheet easily breaks. In addition, major defects such as a reduction in tear resistance are likely to occur. Also, as the PAS fiber becomes thicker, it becomes colored, so PAS with high whiteness
Difficult to mold fibers. Further, when the fineness is high, it is difficult to make paper.

Therefore, the fineness of PAS fiber is 0.3d or less, and especially preferable is
It is less than 0.1d. More preferably, it is 0.07d or less.
The PAS fibers do not have to have a fineness that applies uniformly to the length fragrance, and the point is that the PAS fibers need only have a fineness that does not affect a portion of the fibers. That is, the thickness of the PAS fiber may fluctuate in the length direction, or may be branched into fibrils. This means that the form of the fiber is not limited to the PAS fiber, and the fiber made of the aromatic ring-containing polymer may have the same form. The method for producing such PAS fibers is not particularly limited, and conventionally known methods can be widely applied. That is, for example, a so-called polymer array fiber, a polymer blend fiber, a peelable fiber, and other thinning fibers are produced, and thereafter,
An effective ultrafine fiber manufacturing method can be adopted by peeling treatment or removing at least one component or the like. It is also a very effective means to make ultrafine fibers by means such as melt blowing and flash spinning. In addition, hollow fibers are produced by removing at least one component such as core-sheath fibers, polymer array fibers, and polymer blend fibers among the thinnable fibers. It is also an extremely effective method to form fibers (lotus-root-shaped fibers) and then beaten the fibers to form fibril-like branched fibers. It is also possible to treat the fibers with a high-pressure fluid, for example, water jet or the like, and further to form fibers that are branched into fibrid,
This is an extremely effective method.

The PAS fibers used for the special paper-like sheet of the present invention are mainly composed of short fibers. When short fibers are used as the main constituent fibers, it is easy to exert a great effect that the unit weight is uniform, the product can be made flexible, and the flexibility is increased. The fiber length varies greatly depending on the purpose and application, but 0.5 mm to 150 mm is preferable. Especially when a special paper sheet with high uniformity is used, 0.5 mm to 25 mm is preferable.
Further, when forming a high strength special paper-like sheet, it is preferable to add more long fibers. In any case, in this range, a good paper-like sheet having excellent uniformity and rich flexibility can be obtained.

The PAS ultrafine fibers are preferably drawn.
Particularly preferred is that the film is stretched 1.5 times or more. And, more preferably, it is stretched by 2 times or more. If the draw ratio is less than 1.5, the yarn becomes extremely brittle. Especially when exposed to 90 ° C or higher, the yarn becomes weak. Also, when the yarn is exposed to 90 ° C. or higher with no tension applied, the yarn shrinks extremely, and the yarn becomes extremely weak. That is, when heat resistance is required, it is preferable to stretch by 1.5 times or more. Particularly when heat resistance and sheet strength are required, it is preferable to use PAS ultrafine fibers that have been highly stretched and crystallized to a level of 2 times or more.

In order to improve the heat resistance and chemical resistance of the PAS fiber,
Furthermore, in order to impart hydrophilicity and improve papermaking properties,
It is also very good to modify PAS by applying plasma treatment or oxidizing the sulfur component of PAS, such as polyphenylene sulfonation or polyphenylene sulfoxide. In the process of such processing, PAS
Further, side chains such as —OH groups and those having intramolecular or intermolecular bonds are naturally included in the fiber of the present invention. Needless to say, the fiber may have a sulfonic acid group or the like.
However, such a treatment increases the water absorption rate and the moisture absorption rate of the special sheet material, and some fields are unsuitable for the purpose. Therefore, it is preferable to perform the treatment according to the use and purpose.

Next, the other aromatic ring-containing polymer fibrous material used at least in the present invention will be described. A particularly preferred aromatic ring polymer has a melting point of 300 ° C. or higher. If the temperature is lower than 300 ° C, the heat resistance of the entire special sheet-like material is lowered, which is not preferable.

A particularly preferred aromatic ring-containing polymer is a wholly aromatic ring polymer, or a polymer composed of an aromatic ring and a hetero ring. Typical examples of such compounds are aromatic polyamides such as poly-m-phenylene-iso-phthalamide (hereinafter referred to as PMPI), poly-p-phenylene-tere-phthalamide (hereinafter referred to as PPPT), and poly-P-benz. An amide, a copolymer of such a polymer, and a polymer represented by the following structural formula.

Further, as the aromatic imide, those represented by the following structural formulas are particularly preferable.

Further, it is also particularly preferable that the bond between the aromatic rings of the diamine component, which is the starting material for the imide, is a Fulfide bond or a sulfone bond. Further, as the aromatic amide-imide, those represented by the following structural formula are
Particularly preferred.

Where Z is one of the following, Y is represented by any of the following.

—O—, —CO—, —SO ₂ — Further, those having an aromatic ring mainly bonded by an ether bond or the like are preferably those represented by the following structural formula.

Further, those having an aromatic ring mainly bonded by an ester bond or the like are particularly preferably those represented by the following structural formula.

On the other hand, as a polymer composed of an aromatic ring and a hetero ring, particularly preferable one is polybenzobisoxazole (hereinafter referred to as PB
O), polybenzobisthiazole (hereinafter referred to as PBT), polybenzimidazole (hereinafter referred to as PBI), and the like, which are represented by the following structural formulas are particularly preferable.

As for the morphology of such fibers, various morphologies can be adopted, like the PAS fibers. It may be fibril-shaped or thicker than ultrafine fiber PAS fiber. However, it is particularly preferred that at least part of such fibers are thin. In particular, when it is desired to obtain a high-quality paper-like material, it is preferable that the fiber made of the aromatic ring-containing polymer is 3d or less. And
Particularly preferred is that fibrillated or 0.8d or less, and aromatic ring-containing polymer fibers are mainly constituted.

The method for producing such a fiber is not particularly limited, and a conventionally known method can be applied. The so-called flash spinning method is a very effective method. Further, since such fibers are easily fibrillated by mechanical treatment, it is also extremely effective to make them ultrafine fibers by beating treatment. In addition, by injecting a high-pressure fluid, for example, a water jet stream onto fibers made of these polymers, and by using it in combination with mechanical and chemical beating treatment, ultrafine fibers and fibrillated fibers are obtained. It is also effective to It is also an effective method to add fibrils at the time of molding the fiber to facilitate fibril formation.

Therefore, the particularly preferable aromatic ring-containing polymer is easily fibrillated by such treatment. Good fibrillation makes good papermaking, and therefore makes it easy to produce good paper-like sheets.

So-called rigid fibers are easy to fibrillate, but those not copolymerized are particularly preferred because they are easy to fibrillate. Further, a polymer not copolymerized is particularly preferable because it has high heat resistance, chemical resistance, and strength. Even if the aromatic ring-containing polymer is difficult to fibrillate, it is a particularly effective method for producing ultrafine fibers of PAS. Needless to say, since it is also possible to apply a method of using fibrillated fiber, it does not cause a major obstacle.

The special sheet material of the present invention is composed of at least two polymers, that is, a fiber made of such an aromatic ring-containing polymer and a fiber made of PAS, but contains various other extenders, additives, and papermaking auxiliaries. It goes without saying that you can do it. One of the particularly preferable modes of the present invention is that the PAS fiber which is an ultrafine fiber and the fiber composed of the aromatic ring polymer are adhered or welded. Welding means that an adhesive state is achieved by melting or softening by heat. When such fibers are bonded, that is, when PAS ultrafine fibers and aromatic ring-containing polymers are in an adhesive state, other sizing agents can be dispensed with, and the heat resistance, water resistance, oil resistance, etc. of special sheet materials can be greatly improved. There is a big advantage that. In addition, the amount of the fallen substances from the special sheet material can be extremely reduced, which is extremely preferable for using the special sheet material for clean applications.

Next, regarding the ratio of PAS ultrafine fibers and fibers containing aromatic ring-containing polymers, it varies greatly depending on the use of the special sheet-like material of the present invention, and cannot be said to be unequivocal. Especially when heat resistance is required, it is preferable that the ratio of the fibers containing the aromatic ring polymer is higher. On the other hand, especially when chemical resistance is required, it is preferable that the proportion of PAS ultrafine fibers is higher. In any case, it should be decided according to the purpose and use. However, it is preferable that the ratio of the fiber containing the aromatic ring polymer is at least 10% by weight (hereinafter referred to as Wt%) with respect to the total amount of the special sheet material. If it is less than 10 Wt%, improvement in physical properties such as heat resistance cannot be expected so much. And it is particularly preferable that the amount is 50 Wt% or more, and further preferable is 80 Wt%.
Wt% is a fiber composed of an aromatic ring-containing polymer.
With such a ratio, the heat resistance is significantly improved. On the other hand, the PAS ultrafine fibers are preferably at least 2 Wt% or more.

If it is less than 2 Wt%, the effect of adding PAS fiber is not significant. PAS
The ratio of PAS ultrafine fibers varies significantly depending on the denier of the ultrafine fibers. Therefore, the ratio of PAS ultrafine fibers should be optimized in consideration of the denier of the fibers and the dispersion state (dispersibility) in the special sheet material. Should be.

As a matter of course, it goes without saying that various additives such as lubricants, extenders, brighteners, and various kinds of inorganic fine particles which are insulators may be added. It is also effective to add fibrillated fibrils other than the above.

The basis weight (weighing) and density of the special paper-like sheet of the invention vary greatly depending on its application, and cannot be said unequivocally. It should be decided appropriately depending on the application.

When making the special paper-like sheet of the present invention, as a measure of the density of PAS fibers, it is preferable that the density is low in the case of filter paper, while 0.6-0.7 in the case of medium-quality paper-like special paper-like sheet.
g / cm ^3, in the case of high-quality paper-like special paper-like sheet, 0.9~1g / cm ^3,
Also, 1.2-1.4 g /
Especially preferred is cm ³ . Those having these densities can be obtained by appropriately treating the sheet-like material in the papermaking process and the post-process.

Next, the method for producing the special paper sheet of the present invention will be briefly described.

Regarding PAS fiber and fiber containing aromatic ring polymer,
The method described above is a particularly preferable method. Wet papermaking is particularly preferably used. As a matter of course, static electricity or the like may be used to form a sheet. The PAS fiber may be ultrafine before papermaking or may be ultrafine after papermaking. In particular, in the case of thin fibers such as polymer array fibers and polymer blend fibers, it is more preferable to cut the fibers, make them extremely thin, and then easily form a special paper-like sheet. The papermaking process is not particularly limited, and the conventional method can be used without any problems. In addition, before and after the papermaking process, heat pressing is appropriately performed to perform fusion treatment of PAS ultrafine fibers and aromatic ring-containing polymer, gloss treatment (glossing treatment), lubrication treatment, etc. It doesn't matter.

This will be described in more detail with reference to the following examples. Needless to say, the present invention is not limited to these examples.

〔Example〕

 Hereinafter, it will be described in more detail with reference to examples.

Example 1 A polymer array fiber was produced under the following conditions.

Sea component = polystyrene Island component = PPS island / sea (weight ratio) = 50/50 Number of islands = 36 Spinning temperature = 315 ° C Spinning speed = 1000 m / min Stretching ratio = 2.2 Stretching temperature = 90 ° C Fiber-resistant monofilament denier 3.5d Next, the fibers are aligned and towed, further cut into about 5 mm, and the short fibers are treated with trichlene to remove the polystyrene component. Ultrafine PAS short fibers were obtained. Next, the synthetic pulp mainly composed of DuPont PMPI was mixed and stirred in water so that the former was 10 Wt% and the latter was 90 Wt%, dispersed in water, and then poured onto a 100-mesh stainless wire mesh. Papermaking was carried out in order to obtain a sheet. The papermaking process was easy because the dispersion liquid of synthetic pulp and ultrafine PAS short fibers was uniformly dispersed.

Next, the sheet-like material was passed through a dryer at 315 ° C. to heat-bond the synthetic pulp and the ultrafine PAS short fibers to obtain a special paper-like sheet of the present invention.

This special paper-like sheet is slightly yellowish, but at 200 ℃
Even if it is left in the air for a long time, it has excellent heat resistance such as maintaining sufficient shape (for heat resistance test, a paper sheet was cut into a width of 3 cm and a length of 20 cm, and a clamp length of 15 cm was used. Then, a load of 100 g was applied to the lower end of the paper, and a creep test was performed for 1 hour under heating, and the rupture state of the paper was observed. Judged),
In addition, it is very flexible and extremely water resistant (the water resistance test was performed by cutting a paper sheet into a width of 3 cm and a length of 20 cm,
Make sure that the clamp length is 15 cm and that the bottom of the paper is 20
A load of g was applied, and a creep test was performed for 1 hour in water at 50 ° C, and the rupture condition of the paper was observed. It was judged that a rupture of more than half of the width of 3 cm was not heat resistant), and flexibility Rich,
In addition, it is extremely resistant to chemicals such as no change even when immersed in oil, has excellent flame retardancy, has extremely high electrical insulation, and has excellent radiation resistance. In addition to being used in the conventional paper field, it was also applicable to high-grade filter paper and electrically insulating paper. In addition, there were very few fallen objects from this special paper sheet, and it could be used with confidence in various precision filter papers.

Example 2 A PPS composite fiber was prepared under the same conditions as in Example 1 except that the draw ratio of the PPS composite fiber was 3.5 times, made into ultrafine fibers in the same manner as in Example 1, and then PPS ultrafine fibers and PMPI.
The former and the latter were mixed such that the mixing ratio was 15 Wt% for the former and 85 Wt% for the latter, and paper was made in the same manner as in Example 1 below. Next, the papermaking sheet was passed between calender rolls heated to 300 ° C. and pressed to obtain a high-quality paper having a specific gravity of about 1 g / cm ³ and a thickness of about 50 μm. This special sheet material has a heat resistance of 240 ℃,
It also has high water resistance, excellent fold resistance, no change even when immersed in oil, and extremely high chemical resistance. It also has excellent flame retardancy and extremely high electrical insulation. high,
It could be used not only in the field of conventional paper but also in high-grade filter paper and electrically insulating paper. Moreover, the amount of fallen substances from this special paper-like sheet was smaller than that of Example 1, and it was sufficiently usable in the so-called high-tech field.

Example 3 The special sheet material of Example 2 was subjected to plasma treatment to perform polyphenylene sulfonation treatment of PPS. Surprisingly, the special sheet-like material has excellent heat resistance such that it retains its shape sufficiently even when left in the air at 300 ° C., and Example 2
It had the same physical properties as.

Example 4 In Example 1, the sea and the island were replaced with each other, and a fiber having a fineness of 1.2d after stretching was produced. The draw ratio was 3.6 times. Both spinning and drawing could be carried out smoothly. Thereafter, it was cut in the same manner as in Example 1 (the fiber length of the cut was mainly 1 cm or less) and further treated with trichlene to remove the island component to obtain a multi-hollow PAS fiber of about 0.6d. Then, the multi-hollow PAS fiber was fibrillated by applying a model beater.

The fibrillation could be carried out well, and a fibril-like material was obtained that was partially ultrafine to 0.1d or less (photographed with a scanning electron microscope and d was measured).

Then, PPPT was dissolved in concentrated sulfuric acid by a method similar to the method disclosed in Japanese Examined Patent Publication No. 55-14167, spun by a test spinning machine, and further heat-treated to prepare a fiber having a PPPT of about 1.7 denier. Then, the fiber was knitted into a flat knit, and then the plain knit was treated with high-pressure water (200 kg / cm ² ) from both sides of the flat knit to fibrillate the PPPT. The plain knit was then released and re-threaded, then the thread was cut with a ceramic cutter to about 1 cm or less. Next, the single fiber was put into a beating machine and further fibrillated. The fibrillation was sufficiently and better than PPS.

Next, the PPS ultrafine fibers of Example 2 were 5 Wt%, the fibrillated PPS ultrafine fibers were 10 Wt%, and the fibrillated PPPT was 85 Wt.
% To prepare high-quality paper in the same manner as in Example 2 below. This special sheet-like material is extremely smooth and flexible, and has the same characteristics as those of Example 2, and is heat-resistant, that is, it is hardly affected by the organic solvent.
It was a sheet material with excellent chemical resistance, water resistance, and flame retardancy.

Example 5 The PPS ultrafine fibers of Example 2 were treated with 40% peracetic acid to produce poly-P-phenylenesulfone ultrafine fibers,
Further, the poly-P-phenylene sulfone fiber was immersed in 30% fuming sulfuric acid for 10 seconds to add a sulfonic acid group to the aryl group. Next, it was further treated with an aqueous solution of sodium hydroxide to convert the sulfonic acid group into sodium sulfonate. Next, the synthetic pulp mainly composed of PMPI of Example 1 was mixed so that the former was 45 Wt% and the latter was 55 Wt%, and treated in the same manner as in Example 2 to obtain a special sheet material. In addition,
The papermaking process was particularly good. Next, when a cationic coloring agent was partially applied to the special paper-like sheet by a screen method and subjected to coloring treatment, good coloring and high fastness were obtained. That is, a paper having excellent heat resistance and capable of being colored well was obtained. Note that the special sheet material also had an ion exchange function.

Example 6 Diphenyl ether in PPS of Example 1 has about 1 carbon atoms.
5 parts by weight of the diphenyl ether derivative having two alkyl groups of 5 was added to 100 parts by weight of PPS, and spinning was carried out at a spinning temperature of 300 ° C. The spinning was very successful despite the low temperature. Next, the yarn could be smoothly drawn up to 3.9 times. Thereafter, the same treatment as in Example 2 was carried out to obtain high-quality paper. This paper had the same physical properties as in Example 2, but was particularly excellent in radiation resistance.

Comparative Example 1 Only the island component of Example 1 was spun alone and treated in the same manner as in Example 1 to obtain 3.5d PPS single yarn. This fiber was used in Example 1
The same treatment as described above was performed to obtain a paper-like sheet. However, the paper could not be made satisfactorily, probably because the fibers were thick. The partially formed paper-like sheet was rough and hard, and easily broken, so it was not usable like ordinary paper.

Comparative Example 2 The 3.5d PPS fiber of Comparative Example 1 and a commercially available 2d aromatic amide fiber manufactured by Teijin Ltd. under the trade name "Conex" was cut into about 5 mm, and the former was 10 Wt%, The latter is 90Wt
% So as to obtain
Paper was made, but the paper could not be made satisfactorily because the fiber was thick. The partially formed paper sheet is coarse and hard,
Moreover, it was fragile and could not be used like ordinary paper.

Comparative Example 3 The undrawn yarn of the polymer array fiber made of PPS and polystyrene of Example 1 was gathered to form a tow, and further, about 5 mm.
Then, the sea component was removed with carbon tetrachloride. Next, the former produced synthetic pulp mainly composed of DuPont PMPI.
Wt% and the latter were adjusted so as to be 90 Wt%, and then treated in the same manner as in Example 1 to obtain a paper-like sheet. Paper making was carried out almost in the same manner as in Example 1. Next, the sheet was passed through a drier at 315 ° C, and a test was conducted to heat-bond the synthetic pulp and the ultrafine PAS short fibers. Part of the PPS melted and fell off from the sheet, causing the shape of the sheet to collapse. Oops. Also,
The remaining sheet, which was not broken, was brittle and easily torn.

Comparative Example 4 The former is 50 Wt of the synthetic pulp mainly composed of the extra fine undrawn PPS fiber of Comparative Example 3 and PMPI manufactured by DuPont.
%, And the latter was adjusted to 50 Wt%, and then treated in the same manner as in Example 1 to obtain a paper-like sheet. There were no major problems in papermaking. Next, the sheet was exposed to a high temperature, and was first placed in high-temperature air at 120 ° C to weld the ultrafine PPS fibers and the synthetic pulp mainly composed of PMPI. I couldn't make a decent sheet because it contracted uniformly. Further, a product obtained by placing the sheet in a high temperature air of 270 ° C. and welding the both had a rough and hard feel, and was easily broken when the sheet was folded several times.

Comparative Example 5 According to the method of Example 1 of Japanese Patent Publication No. 55-14163,
That is, isotactic polypropylene was dissolved in methylene dichloride, and the solution was sprayed under high pressure to form a cotton-like material, which was then beaten to obtain fibrillated isotactic polypropylene. Next, the synthetic pulp composed mainly of PMPI manufactured by DuPont, which was used in Example 1, was mixed in the same manner as in Example 1 to produce a paper-like sheet-like material.
The case was able to make paper well, and a good paper-like sheet was made. However, the sheet had no heat resistance at 150 ° C. That is, it could not be used at high temperature.
Also, if it is rubbed with radiation, perhaps because the isotactic polypropylene was easily destroyed by exposure to radiation.
The isotactic polypropylene was easily removed from the paper-like sheet.

Comparative Example 6 50 Wt% of a commercially available natural pulp and the synthetic pulp mainly composed of PMPI used in Example 1 were mixed and made into a paper-like sheet. The case was able to make paper well, and a good paper-like sheet was made. However, this sheet was not water resistant. It also burned easily.

〔The invention's effect〕

By adopting the configuration of the present invention, the following great effects are brought about.

A special paper sheet with extremely high heat resistance can be obtained.

A special paper-like sheet with extremely high water resistance can be obtained.

A special paper sheet with extremely high chemical resistance can be obtained.

In particular, wholly aromatic polyamides, polyimides, polyaramids, and paper sheets made of PBT, PBO, etc. and PPS, etc. are extremely flame-retardant. Further, such a paper-like sheet has all the above features.

In particular, paper-like sheets with a structure in which aromatic ring-containing polymers and PAS fibers such as PPS are adhered (welded) have very few falling off from the sheets. It also has all the characteristics of
It also has the characteristics of specifying an aromatic ring-containing polymer.

In particular, if PAS fibers with an acidic group such as a sulfonic acid group added to the aryl group are used and made into a special paper sheet, it can be easily colored with a cationic adhesive and is difficult to fall off.

Especially when a heat-resistant material is used as the sizing agent, the special paper-like sheet has extremely high heat resistance.

Particularly, an acidic group such as a sulfonic acid group was added to the aryl group.
When PAS fiber is used, a special paper-like sheet having an ion exchange function is obtained, and its heat resistance, hot water resistance, and chemical resistance are extremely high, so the application of ion exchange paper has spread dramatically. .

In particular, when PAS fiber with a diphenyl ether derivative added is used, a sheet with extremely high radiation resistance is obtained.

Claims (3)

(57) [Claims] 1. A special paper-like sheet, which is a fiber made of an aromatic ring-containing polymer having a melting point of 300 ° C. or higher selected from at least poly-phenylene-phthalamide, polybenzobisoxazole and polybenzobisthiazole. , 0.3 denier or less, and containing a polyarylene fiber of the following structural formula consisting mainly of short fibers, characterized in that the fiber comprising the aromatic ring polymer and the polyarylene fiber are bonded or welded Special paper-like sheet. 2. The special paper-like sheet according to claim 1, wherein an acidic group is added to the aryl group of the polymer forming the paper. 3. A special paper-like sheet according to claim 1, which is obtained by adding a diphenyl ether derivative to polyarylene fibers.