JPH09316326A - Polybenzazole composition and fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polybenzazole composition excellent in light and heat resistances by incorporating a specific compound into a polybenzazole. SOLUTION: The composition comprises a polybenzazole and a compound represented by the formula (wherein P is a 6-16C aromatic hydrocarbon group; X and Y each is sulfur, oxygen, nitrogen, or an imino group; Z is carbon or nitrogen; and W is a mercapto, amino, or hydroxyphenyl group). The content of this compound is preferably 0.01-10wt.% based on the polybenzazole. Polybenzazole fibers obtained therefrom are preferred.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a light-resistant agent which imparts excellent light resistance and heat resistance to polybenzazole, and a light-resistant polybenzazole composition containing the light-resistant agent in polybenzazole, And a fiber obtained from the polybenzazole composition.

[0002]

2. Description of the Related Art Recently, as a high heat resistant and high strength fiber, a polymer of polybenzoxazole (PBO), polybenzimidazole (PBI) or polybenzothiazole (PBT) (hereinafter referred to as PBZ or polybenzazole) is used. Fibers are known, for example, they are extruded with a polymer solution from a spinneret, stretched the dope filament in an air gap, optionally further drawn and then washed with water or a mixture of water and an acid solvent and then dried. The method of getting by is adopted.

However, the mechanically damaged polybenzazole fiber tends to have a reduced tensile strength when exposed to oxygen or sunlight. The physical damage includes what is called a kink band that occurs when the fiber is bent or sheared in the weaving or knitting process. Kink bands can be observed as black stripes under a 200X microscope. Fibers that have not been physically damaged do not cause a significant decrease in tensile strength even when exposed to sunlight, but avoid damage when the fibers are processed into various products through weaving and knitting processes. Is very difficult.

[0004]

Therefore, there is a demand for a polybenzazole fiber having a small decrease in strength due to exposure to sunlight even when damaged, and the present invention aims to obtain polybenzazole having a small decrease in strength. This is an issue.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies, researches and studies in order to solve the above-mentioned problems, and as a result, finally completed the present invention. That is, the present invention is a polybenzazole composition characterized by containing a compound represented by the following general formula (I) (hereinafter referred to as a light stabilizer) in polybenzazole, and a fiber obtained from the composition. .

[0006]

Embedded image (In the formula, P is an aromatic hydrocarbon group having 6 to 16 carbon atoms, X, Y
May be the same or different and represent sulfur, oxygen, nitrogen or imino group, Z represents carbon or nitrogen, W represents mercapto group, amino group or hydroxyphenyl group)

In the compound represented by the general formula (I), P is a phenylene group, naphthalene group or the like having 6 to 1 carbon atoms.
6 is an aromatic hydrocarbon group, X and Y may be the same or different, sulfur or oxygen or nitrogen or an imino group, Z is carbon or nitrogen, and examples thereof include benzimidazolyl group, benzothiazolyl group and benzooxa Zolyl group,
Examples thereof include a benzotriazolyl group, and W is represented by a mercapto group, an amino group, a hydroxyphenyl group, or a derivative thereof. Specific examples include 2-mercaptobenzthiazole, 2-mercaptobenzoxazole, 2-mercaptonaphthoxazole, 2-mercaptobenzimidazole, 2-aminobenzthiazole, 2- (2-benzotriazolyl) -p-cresol, 2 Examples thereof include-(2'-hydroxy-5'-t-butylphenyl) -benzotriazole, 2- (2-hydroxyphenyl) benzoxazole and derivatives thereof, but of course the technical content of the present invention is not limited thereto. Not something.

The polybenzazole in the present invention means polybenzoxazole (PBO), polybenzothiazole (PBT) or polybenzimidazole (PBI).
One or more polymers selected from In the present invention, PBO means a polymer containing an oxazole ring bonded to an aromatic group, and the aromatic group does not necessarily have to be a benzene ring. Further, PBO broadly includes polymers composed of poly (phenylenebenzobisoxazole) and a plurality of oxazole ring units bonded to an aromatic group. A similar idea applies to PBT and PBI. Also, two or more PBZs such as a mixture of PBO, PBT and / or PBI, a block or random copolymer of PBO, PBT and PBI, etc.
Also included are mixtures of polymers, copolymers, block polymers. Preferably, the polybenzazole is a lyotropic liquid crystal polymer (forming a liquid crystal at a specific concentration in mineral acid), with polybenzoxazole being preferred in the present invention.

A solution of PBZ polymer (referred to as polymer dope) can be easily prepared by polymerizing the polymer in an acid solvent. The solvent is preferably a mineral acid, for example sulfuric acid, methanesulfonic acid or polyphosphoric acid, most preferably polyphosphoric acid. The polymer concentration in the dope is 5 to 20%, preferably 6 to 1
6%.

Polybenzazole fibers are formed by extruding a polybenzazole dope through a spinneret. Polybenzazole dope is an acid solvent solution of polybenzazole. Random, sequential or block copolymers of PBO, PBT or PBO and PBT are described, for example, in Wolfe et al., US Pat. No. 4,703,103 (1987,10,2).
7), U.S. Pat.No. 4,533,724 (1985,8,6), U.S. Pat.
4,533,693 (1985,8,6), Evers U.S. Pat.No. 4,359,56
7 (1982, 11, 16), U.S. Pat.
86,3,25), 11 Ency.Poly.Sci. & Eng. `` Polybenzothia
zoles and Polybenzoxiazoles '' 601 (J. Wiley & Sons 19
88) or WWAdams et al., `` The Materials Science an
d Engineering of Rigid-Rod Polymers '' (Materials R
esearch Society 1989) etc. Polybenzazoles are considered to be rigid, quasi-rigid or flexible.

In the present invention, suitable polymers or copolymers and dopes are synthesized by known methods, eg Wol.
fe et al., U.S. Pat.No. 4,533,693 (1985,8,6), Sybe
rt et al., U.S. Pat.No. 4,772,678 (1988,9,22), Ha.
rris U.S. Pat.No. 4,847,350 (1989,7,11) or Gregory et al. U.S. Pat.No. 5,089,591 (1992,2,
18). In summary, the preferred monomers are heated in a non-oxidizing, dehydrating acid solution in a non-oxidizing atmosphere under rapid stirring and high shear conditions at a stepwise or constant heating rate from about 120 ° C to 190 ° C. It can be made to react by raising it.

The dope is extruded from the spinneret, stretched in space and formed into filaments. Suitable manufacturing methods are described in the references cited above and in US Pat. No. 5,034,250. The dope exiting the spinneret enters the space between the spinneret and the wash bath. This space, commonly referred to as the air gap, need not be air. This space needs to be filled with a solvent that does not remove the solvent or react with the dope, and examples thereof include air, nitrogen, argon, helium, and carbon dioxide.

After spinning, the filaments are washed to avoid excessive drawing and some of the solvent is removed. Then, it is further washed and appropriately neutralized with sodium hydroxide to remove most of the solvent. The term "washing" as used herein means that the fiber or filament is brought into contact with a liquid that is compatible with the acid solvent in which the polybenzazole polymer is dissolved and is not a solvent for the polybenzazole polymer,
Removing the acid solvent from the dope. Suitable cleaning liquids include water and mixtures of water and acid solvents. The filament preferably has a residual concentration of 8000 ppm or less,
More preferably, it is washed to 5000 ppm or less. After that, the filament is dried, heat-treated, wound, etc., if necessary. The drying here is a step of reducing the amount of water contained in the filament or fiber. The PBZ fiber can be applied to ropes, cables, fiber reinforced composite materials, cut resistant clothing and the like.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As a method for obtaining the composition of the present invention,
That is, the method of incorporating the light-proofing agent into the polybenzazole is not particularly limited, and the polybenzazole may be incorporated in the polymerization step, the dope washing step, the drying step or the post-processing step. Polybenzazole has a porous structure.As a method of applying the lightproofing agent before the washing step or the drying step of the dope, the lightproofing agent is dissolved in water or an organic solvent and the dope, filament or multifilament is dipped. The method is preferred. As a method of applying in a post-processing stage having a rigid structure, a water-insoluble light-proofing agent is dissolved in an organic solvent compatible with water, multifilaments, staples, fabrics, etc. are immersed, and then washed with water. To remove the solvent only, the method of depositing the lightproofing agent on the surface and inside the kink band formed by damage, dissolving the lightproofing agent that dissolves in alkali in an alkaline aqueous solution, dipping multifilament, staple, fabric, etc., later A method of washing with water or a weak acid (for example, acetic acid) to deposit the lightproofing agent inside and on the surface of the kink band is preferable.

[0015]

According to the present invention, the tensile strength retention of damaged polybenzazole fibers when exposed to sunlight is improved as compared to fibers to which these compounds are not added. The decrease in tensile strength is considered to be caused by photooxidative deterioration of the polymer. The damage of the fiber facilitates the permeation of oxygen into the inside of the fiber, so that the oxidative deterioration reaction by light becomes possible. The compound imparted to the fiber in the present invention blocks the transmission of light into the fiber (for example, an ultraviolet absorbing effect), and changes oxygen and benzazole ion radicals as reversible electron conductors into stable neutral substances. Although believed to work, the invention is not bound by this discussion.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples and is appropriately modified within a range compatible with the gist of the preceding and following statements. It is, of course, also possible to add and implement, and all of them are included in the technical scope of the present invention. The characteristic values in the examples were measured by the following methods.

Light exposure test: Using a water-cooled xenon arc weatherometer (manufactured by Atlas, model Ci35A), wrapping the fiber around a metal frame and setting it in the device, quartz on the inner filter glass and borosilicate on the outer filter glass. , Type S, irradiance: 0.35W /
m2 (at 340nm), black panel temperature: 83 ℃ ± 3 ℃,
Humidity in the test tank: Continuous irradiation was performed at 50% ± 5% for 24 hours.

Tensile strength retention rate: PBO multifilament 1m twisting treatment 140 times (twisting factor 6.
0), and after humidity control, it was measured by a Tensilon tester (manufactured by A & D, model RTM250) according to JIS-L1013. Using a 100 kg load cell, gripping interval 20
cm, the pulling speed was 20 cm / min of the gripping interval, and the average value was obtained by repeating the measurement at least 10 times. Then, the tensile strength retention rate was evaluated with respect to the tensile strength of the blank spun yarn that was not subjected to the light resistance treatment and was not subjected to the light exposure treatment.

MBI amount: The total amount of MBI existing inside and outside the filament was determined by measuring sulfur in the PBO multifilament treated with a light-resistant agent by an oxygen flask combustion-ion chromatography method.

Example 1, 22 N-N-Dimethylformamide (D) was prepared by changing the amount of 2-mercaptobenzimidazole (hereinafter referred to as MBI).
MF) was dissolved in 30 ml to prepare a treatment solution, and polybenzoxazole (hereinafter referred to as PBO) undried multifilament (165d, 40yard, about 0.67)
g) was immersed in the treatment solution for 7 hours at room temperature. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. Wipe off excess water with a paper towel, 90 ℃
For 24 hours under vacuum. Tensile strength retention and MB of the obtained PBO multifilament after 24-hour light exposure
The amount of I is shown in Table 1.

Examples 3 and 4 The treatment solution was prepared by changing the amount of MBI and dissolving it in 30 ml of 7 w / v% sodium hydroxide solution, and the same undried PBO multifilament as that used in Example 1 was used. It was immersed in the treatment solution at room temperature for a period of time. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer.
The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 5 A treatment solution was prepared by dissolving 0.25 g of MBI in 30 ml of 7 w / v% sodium hydroxide solution, and the same undried PBO multifilament as in Example 1 was added to the treatment solution at room temperature for 7 hours. Soaked. The excess treatment solution was wiped off with a paper towel, immersed in acetic acid for 5 minutes or more, and washed with running water for 5 minutes or more. Wipe off excess water with a paper towel, 90
After vacuum drying at 24 ° C. for 24 hours, the same evaluation as in Example 1 was performed. Table 1 shows the results.

Comparative Example 1 The same undried PBO multifilament used in Example 1 was immersed in DMF for 7 hours at room temperature. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 1.
Table 1 shows the results.

[0024]

[Table 1] As is clear from Table 1, the tensile strength retention of the PBO fibers to which the light resistant agent MBI is added is 24 to 77%, but PB treated only with DMF having no light resistant agent.
It can be seen that the O fiber has a low value of 19%.

Examples 6 to 8 MBI (5 g) was dissolved in DMF (20 ml) to give a treatment solution.
PBO spun yarn (264d, 20year, about 0.5g)
Was immersed in the treatment solution at room temperature for different times. Wipe off excess treatment solution with a paper towel, wash with running water for 5 minutes or more, and then wipe off excess water with a paper towel.
It was vacuum dried at 0 ° C. for 24 hours. The MBI amount and the tensile strength retention of the obtained PBO spun yarn were measured by the following measuring methods. The results are shown in Table 2.

Tensile strength retention rate: JIS-after humidity control
According to L1095, it was measured by a Tensilon tester (A & D, model RTM250). Using a load cell of 5 kg, the gripping interval was 20 cm, the pulling speed was 20 cm / min of the gripping interval, and measurement was repeated at least 20 times to obtain an average value. Then, the tensile strength retention rate was evaluated with respect to the tensile strength of the blank spun yarn that was not subjected to the light resistance treatment and was not subjected to the light exposure treatment.

Examples 9 and 10 The amount of 10 MBI was changed and dissolved in 20 ml of DMF to give a treatment solution, and the PBO spun yarn used in Example 6 was immersed in the treatment solution for 48 hours at room temperature. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. The results are shown in Table 2.

Comparative Example 2 The untreated PBO spun yarn of Example 6 was evaluated as in Example 6. The results are shown in Table 2.

Comparative Example 3 The untreated PBO spun yarn of Example 6 was treated with D for 48 hours.
Immersion in MF at room temperature. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. The results are shown in Table 2.

Examples 11 and 12 5 g of MBI was dissolved in 20 ml of DMF to prepare a treatment solution.
The untreated PBO spun yarn of Example 6 was immersed in the treatment solution for 48 hours at room temperature. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. After wiping off excess water with a paper towel, ultrasonic cleaning was performed again with the DMF solution for a different time. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. The results are shown in Table 2.

Example 13 5 g of MBI was dissolved in 20 ml of DMF to prepare a treatment solution,
The untreated PBO spun yarn of Example 6 was immersed in the treatment solution for 1 hour at 100 ° C. The excess treatment solution was wiped off with a paper towel and washed with running water for 5 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. The results are shown in Table 2.

[0032]

[Table 2] As is clear from Table 2, the tensile strength retention of the PBO spun yarn to which the MBI, which is a light stabilizer, is shown is 31 to 43%, but the PB treated with only DMF having no light stabilizer is used.
It can be seen that the O spun yarn has a low value of 20%. When ultrasonic cleaning is used (Examples 11 and 12), the MBI applied amount in 10 seconds is 2.9% and the MBI applied amount in 60 seconds is 2.7%. It can be seen that the amount of MBI applied is smaller than that of the same but the strong retention rate is maintained.

Example 14 5 g of 2-aminobenzothiazole was dissolved in 20 ml of DMF to give a treated solution, which was the untreated PBO of Example 6.
The spun yarn was immersed in the treatment solution for 1 hour at 100 ° C. Wipe off excess processing solution with a paper towel, and
It was washed with running water for more than a minute. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. Table 3 shows the results.

Example 15 0.5 g of 2- (2-hydroxyphenyl) benzoxazole was dissolved in 20 ml of DMF to prepare a treatment solution, and the untreated PBO spun yarn in Example 6 was placed in the treatment solution for 100 hours for 1 hour. Soaked at ℃. The excess treatment solution was wiped off with a paper towel and washed with running water for 15 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. Table 3 shows the results.

Example 16 5 g of 2- (2-benzotriazolyl) -p-cresol
Was dissolved in 20 ml of DMF to prepare a treated solution, and the untreated PBO spun yarn of Example 6 was immersed in the treated solution for 1 hour at 100 ° C. The excess treatment solution was wiped off with a paper towel and washed with running water for 15 minutes or longer. The excess water was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. Table 3 shows the results.

Example 17 5 g of 2-mercaptobenzthiazole was added to 20 ml of DMF.
Untreated P in Example 6
The BO spun yarn was immersed in the treatment solution for 1 hour at 100 ° C. Wipe off excess processing solution with a paper towel,
After vacuum drying at 90 ° C. for 24 hours, the same evaluation as in Example 6 was performed. Table 3 shows the results.

Example 18 5 g of 2-mercaptobenzoxazole was added to 20 m of DMF.
The untreated PBO spun yarn in Example 6 was dissolved in 1 l to prepare a treatment solution, which was immersed in the treatment solution for 1 hour at 100 ° C. The excess treatment solution was wiped off with a paper towel, vacuum dried at 90 ° C. for 24 hours, and then evaluated in the same manner as in Example 6. Table 3 shows the results.

Comparative Example 4 5 g of benzoxazole was dissolved in 20 ml of DMF to give a treatment solution, and the untreated PBO spun yarn of Example 6 was immersed in the treatment solution at 100 ° C. for 1 hour. Wipe off excess processing solution with a paper towel and leave at 90 ° C for 24 hours.
After vacuum drying for an hour, the same evaluation as in Example 6 was performed. Table 3 shows the results.

Comparative Example 5 Antioxidant IRGANOX-565 from Ciba Geigy: 5 g in DM
F20 ml was dissolved in F to give a treatment solution, and the untreated PBO spun yarn in Example 6 was placed in the treatment solution for 1 hour and then for 1 hour.
It was immersed at 00 ° C. The excess treatment solution was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then, Example 6 was used.
Was evaluated in the same way as Table 3 shows the results.

Comparative Example 6 5 g of IRGANOX-1098, an antioxidant from Ciba Geigy, was DM
F20 ml was dissolved in F to give a treatment solution, and the untreated PBO spun yarn in Example 6 was placed in the treatment solution for 1 hour and then for 1 hour.
It was immersed at 00 ° C. The excess treatment solution was wiped off with a paper towel and vacuum dried at 90 ° C. for 24 hours, and then, Example 6 was used.
Was evaluated in the same way as Table 3 shows the results.

[0041]

[Table 3] As is clear from Table 3, the tensile strength retention of the PBO spun yarn provided with the light-proofing agent specified in the present invention is 33 to 42%.
However, it can be seen that the PBO spun yarn treated with other compounds has a low value of 23 to 25%.

[0042]

As is clear from Tables 1 to 3, the composition and the fiber having the above-mentioned constitutions have little decrease in the tensile strength even after being exposed to sunlight for a long time, so that the use thereof is possible. The field can be expanded dramatically, and it will greatly contribute to the industrial world.

Claims (3)

[Claims] 1. A polybenzazole composition comprising polybenzazole containing a compound represented by the following general formula (I). Embedded image (In the formula, P is an aromatic hydrocarbon group having 6 to 16 carbon atoms, X, Y
May be the same or different and represent sulfur, oxygen, nitrogen or imino group, Z represents carbon or nitrogen, W represents mercapto group, amino group or hydroxyphenyl group) 2. The polybenzazole composition according to claim 1, wherein the compound represented by the general formula (I) is contained in an amount of 0.01 to 10% by weight based on polybenzazole. 3. A polybenzazole fiber obtained from the polybenzazole composition according to claim 1.