JPS6128530A - Film comprising heteroaromatic polymer and its production - Google Patents

Abstract

PURPOSE:To obtain an isotropic film having excellent heat resistance and mechanical properties, by casting an optically anisotropic dope of a polymer having specified repeating units on a plane heating and coagulating the cast dope. CONSTITUTION:An optically anisotropic dope or flow-birefringent dope of a polymer having repeating units of formula I is cast on a plane and the cast dope is heated and then coagulated. In formula I, Ar is one of formulas II-VIII or their nucleus-substituted products in which the substituents are halogen, alkyl, cyano, nitro and alkoxy. Said polymer may be a copolymer containing two kinds of Ar's. It is preferable that this film has an intrinsic viscosity as determined in methanesulfonic acid at 30 deg.C of >=5, because a polymer of a lower degree of polymerization can not provide good mechanical properties. This film is isotropic, so that the ratio between the initial moduli along two arbitrary rectangularly crossing directions lies in the range in 0.5-2.0.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a film made of a heterocyclic aromatic polymer, and more particularly to an isotropic film with excellent mechanical performance at high temperatures and a method for producing the same. It is something.

(Prior art and its problems) - With the development of electronics and other technologies, there is a strong demand for flexible films that have both excellent heat resistance and mechanical properties. Aramid, aromatic polyimide, aromatic polyether ketone, and the like are known as heat-resistant organic polymers, and films of these materials are being manufactured or prototyped. Some materials have a relatively high moisture absorption rate and are unsatisfactory in terms of electrical insulation and moisture absorption dimensional stability (Aramid, aromatic polyether ketone). aramid), the molding process is complicated (aromatic polyimide), etc.
Each has drawbacks.

(Object of the Invention) In view of these drawbacks of the conventional techniques, an object of the present invention is to provide an isotropic film having both excellent heat resistance and mechanical properties, and a method for producing the same.

The present inventors have focused on the fact that polyparaphenylenebenzobisthiazole (hereinafter abbreviated as PPBT) has the highest heat resistance stability among organic polymers, and have conducted research into making a film from it.

However, since PPBT is an extremely rigid polymer,
It is difficult to obtain an isotropic film because it easily forms liquid crystals in solutions of polyphosphoric acid, methanesulfonic acid, etc., and exhibits flow birefringence even when the polymer concentration is as small as 1% by weight. It was extremely difficult.

However, we discovered the surprising fact that an isotropic film can be obtained by heating these dopes statically before solidifying them, and after further research, we arrived at the present invention.

That is, an object of the present invention is to obtain an isotropic organic film that has excellent heat resistance and excellent mechanical performance.

(Summary of the Invention) The present invention comprises substantially the following repeating units, and their halogen, alkyl, cyano, nitro,
A film whose main component is a polymer selected from the group consisting of alkoxy-nucleically substituted products (which may also be a copolymer consisting of two or more kinds of Ar), the ratio of the initial modulus in two arbitrarily selected directions orthogonal to each other. is 0.5-2.0
This film is characterized in that it is within the range of It can be manufactured by spreading heat and then solidifying it.

The polymer forming the film of the present invention has substantially the following repeating units.

and these halogens, alkyl, cyano, nitro,
selected from the group consisting of alkoxy nuclear substituted products.

Such polymers are known per se and are polymerized in known ways. For example, 2,5-diamino-1,4-benzenedithiol is dissolved in polyphosphoric acid and heated in an inert atmosphere to remove H1! L and then approximately equimolar amount of aromatic dicarboxylic acid and stirring with heating. In this case, two or more types of aromatic dicarboxylic acids may be used to form a copolymer.

The film of the present invention preferably has an intrinsic viscosity of 5 or more, particularly 8 or more, as measured in methanesulfonic acid at a temperature of 30°C, since good mechanical properties cannot be obtained if the polymer has a low degree of polymerization. is preferred.

The film of the present invention is isotropic, and therefore the ratio of the initial assimilated moduli in two arbitrarily selected orthogonal directions is 0.5 to
It is within the range of 2.0. More preferably 0.75 to 1.
It is within the range of 5. Such an isotropic film cannot be obtained simply by extruding the polymer dope of the present invention, but can only be obtained by a special method described below. A film with a ratio of initial modulus in two directions outside the range of 0.5 to 2.0 means that the PPBT polymer is oriented in a certain direction, and the film is easily torn and has no practical value. Significantly decreased.

The film of the invention is preferably transparent. This is because the more transparent the film is, the less uneven the aggregated structure is, and the mechanical properties such as strength are also better.

The film of the present invention preferably has a strength of 51qr/mnf or more and a strength of 100kg/mn? It has an initial modulus of or above. Furthermore, it has excellent heat resistance, and the decomposition temperature measured by thermogravimetric analysis, for example, reaches as high as 600°C (in air).

Next, a method for manufacturing the film of the present invention will be described.

In producing the film, it is first necessary to create an optically anisotropic dope or a fluid birefringent dope from the polymer produced by the method described above. When a dope without optical anisotropy or flow birefringence is formed, the mechanical properties of the film often reach an insufficient level.

In order to impart optical anisotropy or flow birefringence to the PPBT dope, the polymer concentration, the degree of polymerization of PPBT, the temperature,
Select the type of solvent, etc. as appropriate. Among them, the contribution of polymer concentration is very large, and PPB is a very rigid polymer.
In the case of T, it exhibits flow birefringence at about 1% by weight or more (that is, it is optically isotropic under static conditions but exhibits optical anisotropy under shear deformation), and at about 6 to 9% by weight or more Shows optical anisotropy (meaning it shows optical anisotropy even under static conditions).

Therefore, the polymer concentration in the dope used in the production method of the present invention is preferably about 1% by weight or more, more preferably 6% by weight or more. Examples of the solvent in this case include polyphosphoric acid, methanesulfonic acid, chlorosulfuric acid, 98% by weight or more of sulfuric acid, and fluorosulfuric acid. Two or more of these may be used in combination. Sulfuric acid is 100%
A substance with a concentration higher than that, that is, fuming sulfuric acid may be used.

Further, a small amount of hydrofluoric acid, halogenated alkyl sulfonic acid, halogenated aromatic sulfonic acid, trihalogenated acetic acid, phosphorus pentoxide, etc. may be mixed with the above-mentioned solvent. Among these, especially in the case of polyphosphoric acid, it is possible to use the liquid produced by the polymerization reaction as it is, or after concentrating or diluting it, as a so-called direct dope.

Whether the dope has optical anisotropy can be determined by at least one method selected from the "T" test rDDAJ test, observation between polarizing elements, stirring scattered light, etc.
-8474 publication, column 17, line 11 to line 22, last line)
Whether or not a material has flow birefringence can be determined by whether or not it has optical anisotropy when shearing deformation is applied. For convenience, if metallic luster is observed when the dope is stirred, the sufficient condition for optical anisotropy or flow birefringence is satisfied (although this is not a necessary condition).

The dope of the present invention may also contain conventional additives, such as fillers, anti-glare agents, UV stabilizers, heat stabilizers, antioxidants, pigments, solubilizers, etc.

As mentioned above, the dope used in the present invention is kept at room temperature (approximately 20
It has optical anisotropy or flow birefringence at temperatures up to 30°C), but when forming the film, it undergoes the usual operations such as degassing, filtration, and weighing as necessary, before solidifying. It is necessary to first cast the dope onto the planar body and then heat the dope at the same time. Although it is not known exactly how the dope is affected by heating the dope just before solidification, it is likely that the optically isotropic phase in the dope will increase, liquid crystal domain boundaries will become unclear, and monodomain formation will occur. It is presumed that there is a function of

The method of forming a film in the method of the present invention does not require the use of any special method; for example, a method in which the film is uniformly cast onto a glass plate or a metal plate and then formed in a coagulation bath, or a method in which all or most of the bones are placed in a coagulation bath. A method using a immersed rotating drum or a method in which a Teflon sheet or metal sheet is rotated in the form of a belt and a portion thereof is immersed in a coagulation bath can be used. However, heating the dope cast onto these planar bodies is essential in order to obtain a film with isotropically uniform mechanical properties such as initial modulus. The heating temperature varies depending on the conditions of the dope used, but is preferably at least about 80°C, more preferably about 100°C or higher, and most preferably about 120°C or higher.

The upper limit is determined based on the decomposability and operability of PPBT, and is, for example, about 250°C.

The heating method is not particularly limited, and for example, a method of electrically or steam heating the dope transfer curved pipe, high-frequency dielectric heating of the dope flow coming out of the guide or dope on the sheet body, or irradiation of infrared rays. A method of blowing hot air or a method of heating a planar body and then transferring heat may be used, or a combination of these methods may be used. The heating time is approximately 0.1% in consideration of operability and decomposability of the polymer.
The time is preferably at least seconds and at most 15 minutes.

The atmosphere during heating is usually air, but it may be dehumidified to prevent the dope from partially solidifying during casting or heating, or it may be an inert atmosphere such as nitrogen or argon to suppress the decomposition of the polymer. is also one of the preferred embodiments.

Things that can be used as the coagulating liquid for the dope used in the present invention include water, an aqueous solution of about 50% by weight or less of an acid solvent (i.e., polyphosphoric acid, methanesulfonic acid, etc. used for preparing the dope), methanol, ethanol, ethylene glycol, about 50% by weight or less. 3
Examples include an aqueous solution of caustic soda of 0% by weight or less. The temperature of the coagulation bath is not particularly limited, and is usually between 5 and 80℃.
It is carried out in the range of °C.

The production speed of the film of the present invention during continuous production is not particularly limited, but is usually selected between 1 and 150 m/min.

Since the coagulated film as it is contains acid, it is necessary to completely remove the acid content in order to produce a film with excellent mechanical properties. Water is usually used as the cleaning solution, but if necessary, it is also possible to use warm water or neutralize with an alkaline aqueous solution and then rinse with water.
Further, the cleaning method may include running the film in a cleaning liquid or spraying the cleaning liquid.

The film from which the solvent has been removed must be dried.

Here, drying refers to the operation of removing cleaning liquid etc. adhering to the film, and any method may be used as long as the cleaning liquid etc. is removed, such as air drying at room temperature, heated inert gas, such as air, nitrogen, argon. Drying may be performed in an atmosphere such as in a vacuum cleaner or on a heating roll. The drying temperature is not particularly limited, but in consideration of the drying ability and the decomposability of the polymer, a temperature above room temperature and below about 700°C is preferably used, but in special cases where a film with little heat shrinkage is to be produced, about 100°C is used. ℃ or more and about 700°C or less is preferably used. Further, during drying, if excessive tension is applied only in either the width direction or the winding direction, the film will become directional, which is undesirable, and drying is usually carried out under no tension or isotropic tension.

Thus, the film formed by the method of the present invention,
It has excellent mechanical properties as it is formed, that is, when it is simply solidified, washed with water, and dried (without tension or under slight tension), even without stretching heat treatment. However, depending on the purpose, it is also possible to perform biaxial stretching to impart even better mechanical properties.

In producing the film by the method of the present invention, the above steps may be carried out batchwise or continuously, and in a preferred embodiment, the film may be produced while running continuously throughout the entire process. There is one. Further, an oil agent, an identification dye, etc. may be applied to the film in an arbitrary step.

(Effects of the Invention) The first effect of the present invention is that, for the first time, it has been possible to successfully obtain a film having isotropic properties from PPBT, which has the highest heat resistance among organic polymers. The film of the present invention has an almost isotropic initial modulus and also has no anisotropy in strength and elongation. Therefore, it does not tend to tear in any particular direction. Furthermore, the film of the present invention has good mechanical properties even without a stretching step after forming, has a strength of 5 kIr/mrrl or more, and has a strength of 100 kg/mrl or more.
It has an initial modulus greater than or equal to rF. In addition, it is flame retardant and has good chemical resistance.

The film of the present invention is useful as an electrical insulating material, a wire covering material, an electronic circuit board, a magnetic memory material support, a filtration membrane, a packaging material, etc. by making use of the above-mentioned properties.

(Examples of the Invention) Examples of the present invention are shown below, but these do not limit the present invention. Note that parts or percentages in Examples are parts by weight or weight percentages unless otherwise specified. show. In addition, the strength and elongation and Young's modulus are measured using a constant speed extension type strength and elongation measuring device.
Cut the film sample into a rectangle of 100 cranes x 20 m,
A load-elongation curve was drawn at an initial gripping length of 50° C.m and a tensile speed of 25/min, and calculations were made from this.

Example 1 Wolfe et al. (Macromolecules.

14S, p. 915 (1981)), 7 g of 2,5-diamino-1,4-benzenethiol dichloro, ride 3B, was weighed in a nitrogen box and thoroughly degassed. It was added to a cylindrical separable flask equipped with a stirring blade containing 209 g of polyphosphoric acid, stirred at room temperature under a nitrogen atmosphere for about 24 hours, and then heated to 65°C for about 3 hours.
Stirring was continued for 0 hours to completely remove hydrogen chloride. Next, 26.2 g of terephthalic acid was added, and 287 g of degassed polyphosphoric acid was added, and the mixture was stirred at 110°C for about 5 hours, then the temperature was raised to 165°C, and the mixture was stirred at 165°C for 12 hours. The temperature was raised to 180°C and stirred at 180°C for 12 hours, and finally the temperature was raised to 190°C and stirred at 190°C for 5 hours to complete the polymerization reaction. A portion of the resulting PPBT polymer was isolated and the intrinsic viscosity measured in methanesulfonic acid at 25°C was 8°2.

At the end of the polymerization, the polyphosphoric acid contained 8% by weight of the polymer, and exhibited optical anisotropy in the range from room temperature to about 200°C. Polyline some of this dope.

A 2.0% by weight dope was prepared by diluting with acid. This dope exhibited birefringence under shear stress.

The diluted dope was cast onto a glass plate in an oven heated to 90° C. using an applicator with 0.25 fi spacing. After standing in air at 90°C for about 3 minutes, it was placed in water at room temperature to solidify. After washing with water overnight, 80
A film with a thickness of about 15 μm was obtained by constant length drying in an oven at °C. The film is transparent and has a strength of 9.6 kg/m cd and 8.9 in the direction of the applicator, in the direction perpendicular to it, and in the direction 45° to it, respectively.
kg/m rd, 9.0 ksr/m-, and the initial moduli are 370 kg/m, cd, 280, respectively.
kg/mar, 330 kg/mrrr.

Further, even when this film was heated from room temperature to 250°C, no dimensional change was observed. Also, 10 Ω'''11-1'
It showed only 11-1 or less, indicating good electrical insulation.

Example 2 Using the same method as in Example 1, the as-polymerized dope was used to form a film at about 180°C. In this case, a mirror-finished stainless steel plate is heated to 180°C, a dope preheated to about 150°C is cast onto it in a nitrogen atmosphere, heated for about 10 minutes, and then Coagulation was performed using a 10% aqueous phosphoric acid solution at 50°C as a coagulation liquid.

The film obtained by washing with water and drying as in the case of the diluted dope had a thickness of 48 μm. When the strength was measured in the same way as the film obtained from the diluted dope, it was 12.11 g/
mn? , 9.31g/mnr, 9.9 b/mrr
r, and the initial modulus is 490 kg/mr+? ,
3201g/mn? , 290 kg/mn? Met.

Example 3 PPBT with an intrinsic viscosity of 15.3 was obtained in the same manner as in Example 1, and this was remelted in methanesulfonic acid at room temperature to 50°C to prepare a 12% by weight optically anisotropic dope.

After degassing, the dope is pumped using a metering gear pump and discharged into a space heated to about 200°C, and while the dope stream is heated with an infrared lamp, it flows onto a stainless steel belt moving at about 5 m/min. It was extended. The stainless steel belt holding the dope was constructed to enter a heating chamber in which a nitrogen stream of about 200 to 210°C was circulated, so that it could be heated to about 200°C from both the top and bottom. After the dope remained in this heating chamber for about 7 minutes, it was immersed together with the belt in a coagulation bath consisting of a 10% methanesulfonic acid aqueous solution, and then peeled off from the belt. The taken out film was washed with a 0.3% caustic soda aqueous solution, then water, and dried at 150° C. for a fixed length. As a result, a transparent and strong film was obtained, whose strength in the winding direction and initial modulus were 16±4 kg, respectively.
/ m rd, 350±70ksr/mnf, the strength and initial modulus in the direction perpendicular to the width are 11±2kg, respectively.
/mrrr, 260±30kg/mrd. Note that these data show the average value and existence range of the measured values when η=7.

Claims (3)

[Claims] (1) A polymer having substantially the following repeating units ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (Here, Ar is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and these halogens, alkyls, cyano, nitro,
A film whose main component is a copolymer selected from the group consisting of alkoxy nuclear substituted products, which may be a copolymer containing two or more types of Ar, and whose initial modulus ratio in two arbitrarily selected mutually orthogonal directions is 0.5. A film made of a heterocyclic aromatic polymer, characterized in that the molecular weight is within the range of 2.0 to 2.0. (2) The film according to claim 1, comprising a polymer having an intrinsic viscosity of 5 or more when measured in methanesulfonic acid at a temperature of 30°C. (3) A polymer having substantially the following repeating units▲There are mathematical formulas, chemical formulas, tables, etc.▼ (Here, Ar is ▲There are mathematical formulas, chemical formulas, tables, etc.▼,
▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and these halogens, alkyls, cyano, nitro,
An optically anisotropic dope or a fluid birefringent dope (selected from the group consisting of alkoxy nuclear substituted products and may be a copolymer containing two or more types of Ar) is cast onto a planar body, heated, and then solidified. A method for producing a film made of a heterocyclic aromatic polymer characterized by