JPH11228820A - Polybenzazole composition, fiber and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition with slight oxidative deterioration when exposed to sunlight, and useful for fibers and films by including a specific compound in a polybenzazole. SOLUTION: This composition is obtained by incorporating (A) a polybenzazole with (B) metallic copper and/or a copper compound wherein, preferably, the component B is included in the form of metallic copper or copper ion at 0.01-10 wt.%, based on the component A. For example, it is preferable that, as the component A, e.g. polybenzoxazole is used and, as the component B, e.g. copper, cuprous chloride (I), cuprous iodide (I) or cuprous oxalate (I) is used. Also, it is preferable that the polybenzazole is polymerized in an acidic solvent, such as a mineral acid, particularly, polyphosphoric acid, and then, the component B is mixed in the resultant polybenzazole dope.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-resistant agent which gives polybenzazole excellent light resistance and heat resistance, and a light-resistant polybenzazole composition comprising the light resistant agent in polybenzazole. And fibers and films obtained from the polybenzazole composition.

[0002]

2. Description of the Related Art Recently, a fiber made of a polymer of polybenzoxazole, polybenzimidazole or polybenzothiazole (hereinafter referred to as polybenzazole) is known as a high heat-resistant and high-strength fiber.
A method is employed in which a polymer solution is extruded from a spinneret, a dope filament is stretched in an air gap, and if necessary, further stretched, washed with water, and then dried.

[0003] Normally, fibers that have not been physically damaged do not cause a significant decrease in tensile strength when exposed to sunlight, whereas polybenzazole fibers that have been physically damaged do not contain oxygen or sunlight. When exposed to, its tensile strength tends to decrease. Physical damage includes
For example, there is a so-called kink band generated when a fiber is bent or sheared in a weaving or knitting process. The kink band can be observed as a black stripe under a microscope at a magnification of 200 times. Weaving fibers,
It is very difficult to avoid damage when processing into various products through the knitting process. Cracks tend to occur in the film.

[0004]

Therefore, there is a demand for a polybenzazole fiber having a small strength decrease due to sunlight exposure even when damaged, and the present invention aims at obtaining a polybenzazole fiber having a small strength decrease. It is an object of the present invention to obtain polybenzazole with little oxidative deterioration when exposed to sunlight.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have finally completed the present invention. That is, the present invention is a polybenzazole composition characterized in that polybenzazole contains metallic copper (hereinafter referred to as copper) and / or a copper compound, and a fiber and a film obtained from the composition.

[0006] Specific examples of copper or copper compound to be blended in the present invention include copper, copper (I) chloride, copper (I) iodide, copper (I) oxalate, copper (II) chloride, copper iodide. (II), copper oxalate (II), copper thiocyanide (I
I), copper (II) acetate, copper (II) bis (acetylacetonate), copper (II) ammonium chloride, copper carbonate (I
I), copper (II) citrate, copper cyclohexylbutyrate, copper diphosphate, copper (II) fluoride, copper (II) formate, copper (II) gluconate, copper (II) naphthenate, copper oleate ( II), copper (II) oxalate, copper (II) phthalate,
Phthalocyanine blue and the like. Particularly preferably, a monovalent copper compound is used. Further, these copper compounds may be used in combination with one or more compounds. The content of copper or copper compound with respect to polybenzazole is 0.01 to 10% by weight, preferably 0.05 to 5% by weight, particularly 0.1 to 3% by weight as copper or copper ions. Of course, the technical contents of the present invention are not limited to these.

[0007] The polybenzazole in the present invention refers to one or more polymers selected from polybenzoxazole (hereinafter referred to as PBO), polybenzothiazole (hereinafter referred to as PBT) and polybenzimidazole (hereinafter referred to as PBI). In the present invention, PBO refers to a polymer containing an oxazole ring bonded to an aromatic group,
The aromatic group need not necessarily be a benzene ring.
Further, PBO widely includes polymers composed of poly (phenylenebenzobisoxazole) and a plurality of oxazole ring units bonded to an aromatic group. Similar considerations apply to PBT and PBI. Also, PBO, P
Also included are mixtures, copolymers, block polymers of two or more polybenzazole polymers, such as mixtures of BT and / or PBI, block or random copolymers of PBO, PBT and PBI, and the like. Preferably, the polybenzazole is a lyotropic liquid crystal polymer (forms a liquid crystal at a certain concentration in a mineral acid),
In the present invention, polybenzoxazole is preferred.

The polybenzazole dope is a solution of polybenzazole in an acid solvent, and can be easily prepared by polymerizing a polymer in an acid solvent. The solvent is preferably a mineral acid, such as sulfuric acid, methanesulfonic acid, or polyphosphoric acid, but most preferably polyphosphoric acid. The polymer concentration in the dope is between 5 and 20
%, Preferably 6 to 16%.

The polybenzazole fiber is formed by extruding a polybenzazole dope from a spinneret. The polybenzazole film is formed by pressing a polybenzazole dope and then uniaxially or biaxially stretching it. PBO, P
BT or random, sequential or block copolymers of PBO and PBT are described, for example, in Wolfe et al., U.S. Pat. No. 4,533,693 (1985,8,6); Evers, U.S. Pat. U.S. Patent 4,
No. 578,432 (1986, 3, 25), 11 Ency. Poly. Sci. & Eng.
`` Polybenzothiazoles and Polybenzoxazoles '' 601
(J. Wiley & Sons 1988) or WW Adams et al.
Materials Science and Engineering of Rigid-Rod Pol
ymers "(Materials Research Society). Polybenzazole is considered to be rigid, quasi-rigid or flexible.

In the present invention, suitable polymers or copolymers and dopes are synthesized by known methods. For example, Wo
lfe et al., U.S. Patent No. 4,533,693 (1985,8,6);
U.S. Pat. No. 4,772,678 to Sybert et al.
2), Harris U.S. Pat. No. 4,847,350 (1989, 7, 1).
1) or US Pat. No. 5,089,591 to Gregory et al. (1992, 2, 18). In summary, suitable monomers are from about 120 ° C. to 190 ° C. under high speed stirring and high shear conditions in a non-oxidizing and dehydrating acid solution in a non-oxidizing atmosphere.
The reaction is carried out by increasing the temperature stepwise or at a constant heating rate up to ° C.

The dope is extruded from a spinneret and stretched in space to form a filament. Suitable processes are described in the references mentioned above and in U.S. Pat. No. 5,034,250. The dope that has exited the spinneret enters the space between the spinneret and the washing bath. This space is commonly referred to as an air gap, but need not be air. This space must be filled with a solvent that does not remove or react with the dope, such as air, nitrogen, argon,
Helium, carbon dioxide and the like can be mentioned.

[0012] The spun filaments are washed and a part of the solvent is removed to avoid excessive drawing. And
It is further washed and appropriately neutralized with an alkali such as sodium hydroxide, and most of the solvent is removed. Washing here refers to removing the acid solvent from the dope by bringing the fiber or filament into contact with a liquid that is compatible with the acid solvent in which the polybenzazole polymer is dissolved and does not become a solvent for the polybenzazole polymer. It is to be. Suitable cleaning liquids include water or a mixture of water and an acid solvent.
The filament preferably has a residual concentration of 8000 ppm
Hereafter, it is more preferably washed to 5000 ppm or less. Thereafter, the filament is subjected to drying, heat treatment, winding, and the like as necessary. The term “drying” as used herein refers to a step of reducing the amount of water contained in filaments or fibers. Polybenzazole fibers can be applied to ropes, cables, fiber-reinforced composite materials, cut-resistant garments, and the like.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a method for obtaining the composition of the present invention,
In other words, the method for incorporating the light-resistant agent into polybenzazole is not particularly limited, and the light-resistant agent can be incorporated in the polybenzazole polymerization step, the dope washing step, the drying step, or the post-processing step. As a method of imparting a light-fast agent at the polymerization stage of polybenzazole, a method of charging the light-fast agent at the same time as the raw material is prepared, a step-wise or light-fastening at any time when the temperature is raised at a constant heating rate and the reaction is performed. A method of adding an agent or a method of adding a light stabilizer at the end of the polymerization reaction is preferred. Polybenzazole has a porous structure as a method of imparting a lightproof agent before the washing step or drying step of the dope, dissolving the lightproof agent in water or an organic solvent, dope, filament, multifilament or film. The immersion method is preferred. As a method of application in the post-processing stage after a rigid structure is obtained, a water-insoluble light stabilizer is dissolved in an organic solvent compatible with water, multifilaments, staples, fabrics and the like are immersed, and then washed with water. A method of precipitating a light-resistant agent on the surface and inside a kink band formed by damage, removing the solvent alone, dissolving the light-resistant agent soluble in alkali in an aqueous alkali solution, immersing the multifilament, staple, fabric, film, After that, a method of washing with water or a weak acid (for example, acetic acid) to precipitate a light resistant agent inside the kink band and on the surface is preferable.

According to the present invention, the oxidative deterioration of the polybenzazole composition when exposed to sunlight is improved as compared with a composition not provided with these compounds. It is considered that the decrease in tensile strength is caused by photooxidative degradation of the polymer. Damage to the fiber facilitates the permeation of oxygen into the fiber, thereby enabling an oxidative degradation reaction by light. The compound imparted to the fiber in the present invention blocks the transmission of light into the fiber (for example, an ultraviolet absorbing effect), or converts oxygen or benzazole ion radical as a reversible electronic conductor into a stable neutral substance. It is believed that they do work, but the invention is not bound by this consideration.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples, and appropriate modifications may be made within a range that can conform to the gist of the preceding and following examples. In addition, it is of course possible to implement them, and all of them are included in the technical scope of the present invention. In addition, each characteristic value in an Example was measured by the following method.

(1) Light exposure test: Using a water-cooled xenon arc type weather meter (manufactured by Atlas Co., type Ci35A), a film was fixed to a metal frame, and the film was set in the apparatus. Quartz was used for the inner filter glass, and outer filter glass was used. Using borosilicate, type S, irradiance:
Irradiation was performed continuously at 0.35 W / m ² (at 340 nm), black panel temperature: 60 ° C. ± 3 ° C., and humidity in the test tank: 50% ± 5% for 20 hours.

(2) Infrared absorption spectrum: After the above-mentioned film-like polybenzazole was irradiated with xenon light, the infrared absorption spectrum of the surface was measured by a micro ATR method. 1680c newly appearing after xenon light irradiation with a common absorption intensity of 1620 cm ^-1 before and after xenon light irradiation
The absorption intensity at m ^-1 was normalized.

(3) Tensile strength retention rate: After twisting (twist coefficient 6.0) 140 times with respect to 1 m of polybenzazole multifilament, and adjusting the humidity, JIS-L10
13 according to Tensilon tester (A & D, model RT
M250). Using a 100 kg load cell, the gripping distance was 20 cm, and the pulling speed was 20 cm / min of the gripping distance, and the measurement was repeated ten times to obtain an average value. Then, the evaluation was made based on the tensile strength holding ratio with respect to the tensile strength of the spun yarn of the blank not subjected to the light exposure treatment and not subjected to the light exposure treatment.

REFERENCE EXAMPLE 1 Method for producing polybenzazole film A sol phosphoric acid solution (PBO-doped or PBT-doped) was prepared. 100 g of the dope and 0.3 g of the light stabilizer were added to Haak.
e Rheocord 90 in a nitrogen atmosphere at 200 ° C
For 20 minutes. The obtained dope is treated at 200 ° C. for 15 minutes.
Pressure was applied at 0 kgf / cm ² for 15 seconds to form the polybenzazole into a film. This was washed with water to remove the solvent, and then dried under reduced pressure for 24 hours.

Reference Example 2 Method for Producing Polybenzazole Fiber The polybenzazole dope prepared in Reference Example 1 was used at a spinning temperature of 150 ° C. at a pore diameter of 160 μm and a pore number of 3
Extrude the filaments from the 40 nozzles into a first cleaning bath arranged to converge at an appropriate location into a multifilament, the filament diameter being 11.5 microns,
1.5 denier fiber was obtained. In the air gap between the spinning nozzle and the first cleaning bath, a quench chamber was provided so that the filament could be drawn at a more uniform temperature. The air gap length was 30 cm. The filament was spun into air at 60 ° C. Take-up speed 2
The spinning draw ratio was set to 30 m / min. Water washing was performed until the residual phosphoric acid concentration in the polybenzazole fiber became 5000 ppm or less.

Example 1 0.3 g of copper (I) chloride was mixed with 100 g of PBO dope as in Reference Example 1, pressed under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBO film. P obtained
Table 1 shows the ratio of the infrared absorption spectrum (1680 cm ^-1 / 1620 cm ^-1 ) of the BO film after exposure to xenon light for 20 hours.

Example 2 0.3 g of copper (I) iodide was mixed with 100 g of PBO dope as in Reference Example 1 and pressed under heating to form a film.
After washing with water, it was dried under reduced pressure to obtain a PBO film. Ratio of infrared absorption spectrum of the obtained PBO film after exposure to xenon light for 20 hours (1680 cm ⁻¹ / 1620 cm ⁻¹ )
Are shown in Table 1.

Example 3 To 100 g of PBO dope, 0.3 g of copper (I) oxalate was mixed as in Reference Example 1, pressurized under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBO film. . The ratio of the infrared absorption spectrum of the obtained PBO film after exposure to xenon light for 20 hours (1680 cm ⁻¹ / 1620 cm)
^-1 ) is shown in Table 1.

Example 4 0.3 g of copper (I) thiocyanate was added to 100 g of PBO dope.
Were mixed as in Reference Example 1, pressed under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBO film. Ratio of infrared absorption spectrum of the obtained PBO film after exposure to xenon light for 20 hours (1680 cm ⁻¹ / 1620c)
m ^-1 ) are shown in Table 1.

Example 5 0.3 g of phthalocyanine blue was added to 100 g of PBO dope.
Were mixed as in Reference Example 1, pressed under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBO film. Ratio of infrared absorption spectrum of the obtained PBO film after exposure to xenon light for 20 hours (1680 cm ⁻¹ / 1620c)
m ^-1 ) are shown in Table 1.

Example 6 0.3 g of copper (I) chloride was mixed with 100 g of PBT dope as in Reference Example 1, pressed under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBT film. P obtained
Table 1 shows the ratio (1680 cm ⁻¹ / 1620 cm ⁻¹ ) of the infrared absorption spectrum of the BT film after exposure to xenon light for 20 hours.

Example 7 0.3 g of copper (I) iodide was mixed with 100 g of PBT dope as in Reference Example 1 and pressed under heating to form a film.
After washing with water, it was dried under reduced pressure to obtain a PBT film. Ratio of infrared absorption spectrum of the obtained PBT film after exposure to xenon light for 20 hours (1680 cm ⁻¹ / 1620 cm ⁻¹ )
Are shown in Table 1.

Example 8 0.3 g of copper (I) chloride was mixed with 100 g of a random copolymer dope of PBO and PBT as in Reference 1, pressed under heating to form a film, washed with water, and dried under reduced pressure. A copolymer film was obtained. Ratio of infrared absorption spectrum of the obtained copolymer film after exposure to xenon light for 20 hours (168)
The 0cm ^-1 / 1620cm ^-1) shown in Table 1.

COMPARATIVE EXAMPLE 1 100 g of PBO dope was added to Haake Rheocord.
After heating and stirring at 200 ° C. in 90, pressure was applied under heating to form a film, washed with water, and dried under reduced pressure to obtain a PBO film. Ratio of infrared absorption spectrum of the obtained PBO film after exposure to xenon light for 20 hours (1680 cm ^-1)
/ 1620 cm ^-1 ) is shown in Table 1.

Comparative Example 2 0.3 g of tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane was mixed with 100 g of PBO dope as in Reference Example 1, and heated under heating. The film was pressurized, washed with water, and dried under reduced pressure to obtain a PBO film. Table 1 shows the ratio of the infrared absorption spectrum (1680 cm ^-1 / 1620 cm ^-1 ) of the obtained PBO film after exposure to xenon light for 20 hours.

[0031]

[Table 1]

Example 9 In the same manner as in Reference Example 2, 30 g of copper (I) chloride was added to 10 kg of PBO dope, and the mixture was stirred at 200 ° C. for 20 minutes in a nitrogen stream. This was spun and washed with water to obtain an undried multifilament of PBO.
For 24 hours to obtain a PBO multifilament. Table 2 shows the tensile strength retention of the obtained PBO multifilament after light exposure for 20 hours.

Example 10 In the same manner as in Reference Example 2, 30 g of copper (I) iodide was added to 10 kg of PBO dope, followed by stirring at 200 ° C. for 20 minutes in a nitrogen stream. This is spun and washed to obtain an undried multifilament of PBO.
Vacuum dried at 24 ° C. for 24 hours to obtain a PBO multifilament. Table 2 shows the tensile strength retention of the obtained PBO multifilament after light exposure for 20 hours.

Example 11 In the same manner as in Reference Example 2, 30 g of copper (I) oxalate was added to 10 kg of PBO dope,
Stirred for minutes. This was spun and washed with water to obtain an undried multifilament of PBO.
Vacuum drying was performed at 0 ° C. for 24 hours to obtain a PBO multifilament. Table 2 shows the tensile strength retention of the obtained PBO multifilament after light exposure for 20 hours.

Example 12 In the same manner as in Reference Example 2, 30 g of copper (I) thiocyanate was added to 10 kg of PBO dope, and the mixture was stirred at 200 ° C. for 20 minutes in a nitrogen stream. This is spun and washed with water to produce PB
An undried multifilament of O was obtained, and this filament was vacuum dried at 90 ° C. for 24 hours to obtain a PBO multifilament. 20 of the obtained PBO multifilament
Table 2 shows the tensile strength retention after the light exposure for hours.

Example 13 In the same manner as in Reference Example 2, 30 g of phthalocyanine blue was added to 10 kg of PBO dope, and the mixture was stirred at 200 ° C. for 20 minutes in a nitrogen stream. This is spun and washed with water to produce PB
An undried multifilament of O was obtained, and this filament was vacuum dried at 90 ° C. for 24 hours to obtain a PBO multifilament. 20 of the obtained PBO multifilament
Table 2 shows the tensile strength retention after the light exposure for hours.

Example 14 In the same manner as in Reference Example 2, 30 g of copper (I) iodide was added to 10 kg of PBT dope, followed by stirring at 200 ° C. for 20 minutes in a nitrogen stream. This was spun and washed with water to obtain an undried multifilament of PBT.
Vacuum drying was performed at 24 ° C. for 24 hours to obtain a PBT multifilament. Table 2 shows the tensile strength retention of the obtained PBT multifilament after light exposure for 20 hours.

Comparative Example 3 In the same manner as in Reference Example 2, 10 kg of PBO dope was stirred at 200 ° C. for 20 minutes in a nitrogen stream. This is spun and washed with water to obtain an undried multifilament of PBO, and the filament is vacuum dried at 90 ° C. for 24 hours to obtain a PBO.
A multifilament was obtained. Table 2 shows the tensile strength retention of the obtained PBO multifilament after light exposure for 20 hours.

Comparative Example 4 In the same manner as in Reference Example 2, tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane 3
After adding 0 g, the mixture was stirred at 200 ° C. for 20 minutes under a nitrogen stream. This is spun and washed with water to obtain an undried multifilament of PBO.
After vacuum drying for a time, a PBO multifilament was obtained. Table 2 shows the tensile strength retention of the obtained PBO multifilament after light exposure for 20 hours.

[0040]

[Table 2]

As is clear from Tables 1 and 2, the PBO to which the monovalent copper compound of the present invention has been added can be a PBO having no light-fastening agent or tetrakis [3-
It can be seen that oxidation is suppressed and the tensile strength is improved as compared with the system provided with (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane.

[0042]

As described above, the composition, fiber and film having the above-mentioned constitution are less oxidized even after being exposed to sunlight for a long time, so that the field of use can be greatly expanded and contribute to the industry. It is big to do.

Claims (4)

[Claims] 1. A polybenzazole composition comprising polybenzazole containing metallic copper and / or a copper compound. 2. The method according to claim 1, wherein the copper metal and / or the copper compound is present in the polybenzazole in an amount of 0.04 as copper metal or copper ion.
The polybenzazole composition according to claim 1, which is contained in an amount of 1 to 10% by weight. 3. A polybenzazole fiber obtained from the polybenzazole composition according to claim 1. 4. A polybenzazole film obtained from the polybenzazole composition according to claim 1.