JP2000038371A - 4,6-diaminoresorcinol-containing composition, polybenzobisoxazole afforded using the same, molded form of the polybenzobisoxazole and stabilization of 4,6- diaminoresorcinol during its storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition with excellent storage stability, capable of affording a polybenzobisoxazole formable into high-strength, high- modulus fibers or the like by including a diaminoresorcinol and a ferric compound as a reducing agent. SOLUTION: This composition is obtained by including (A) 4,6- diaminoresorcinol (salt) and (B) a ferric compound as a reducing agent at >=100 ppm, pref. >=1,000 ppm, more pref. >=2,000 ppm in terms of iron(II) based on the component A [pref. ferric chloride (tetrahydrate), ferric phosphate octahydrate, or the like]. The 2nd objective polybenzobisoxazole with an intrinsic viscosity of pref. >=20 dL/g, more pref. >=25 dL/g, but up to 45 dL/g or so is obtained by reaction between the above composition and an aromatic dicarboxylic acid. The 3rd objective molded form is obtained by forming the above polybenzobisoxazole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a composition containing 4,6-diaminoresorcinol and a salt thereof (hereinafter also referred to as DAR) having good storage stability.
The present invention also relates to a polybenzbisoxazole (hereinafter, also referred to as PBO) which can be formed into a high-strength, high-modulus fiber or heat-resistant film using the same. Furthermore, the present invention relates to a method for stabilizing the storage of DAR.

[0002]

2. Description of the Related Art DAR is a raw material of PBO that can be processed into high-strength, high-modulus fibers and heat-resistant films. This DAR has a drawback that it is very easily oxidized, and even if PBO is polymerized using the oxidized DAR as a raw material, only a low-polymerization degree PBO polymer discolored to green or purple can be obtained. Therefore, as a DAR storage stabilizer, S
Attempts have been made to stabilize DAR by adding nCl ₂ and hydrates thereof.

[0003]

In the production of PBO, polyphosphoric acid is generally used as a solvent. PB obtained
O is usually used in the form of a dope for forming fibers and the like. For example, when forming into a fiber, the dope yarn obtained by discharging the PBO dope is led to an extraction bath such as water or alcohol, where the polyphosphoric acid in the dope yarn is extracted and about 20% phosphoric acid waste liquid is removed. Become. The phosphoric acid waste liquid is concentrated and regenerated into polyphosphoric acid, and is used again as a solvent for producing PBO.

[0004] Here, the PBO dope starting from DAR using SnCl ₂ or its hydrate as a reducing agent contains the added tin as it is.
When a dope is used, tin is also extracted together with the polyphosphoric acid in the molding step, and the phosphoric acid waste liquid contains tin, which is not necessarily environmentally unfavorable to heavy metals. Such a phosphoric acid waste solution is difficult to dispose, and it becomes an obstacle when the waste solution is reused again for a PBO production solvent or other uses.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to reduce a waste liquid generated in a PBO molding process so that the waste liquid can be discarded or reused without imposing an environmental burden. An object of the present invention is to provide a storage-stabilized DAR. Another object of the present invention is to provide a PBO having a high degree of polymerization and a good yellow color tone, and a molded product of the PBO, and a further object of the present invention is to provide a method for stabilizing the storage of DAR.

[0006]

Means for Solving the Problems As a result of extensive studies to achieve the above object, the present inventors have found that the addition of an iron (II) compound to a DAR as a DAR storage stabilizer allows the storage stability of the DAR to be improved. The present inventors have found that a PBO polymer having a high degree of polymerization and a good color tone with a high degree of polymerization can be obtained, and that the waste liquid generated in the PBO molding step does not impose a load on the environment, thereby completing the invention.

That is, the present invention is as follows. (1) 4,6-diaminoresorcinol or a salt thereof,
A composition comprising an iron (II) compound. (2) The composition according to (1), wherein the iron (II) compound is contained in an amount of 100 ppm or more in terms of iron (II) based on 4,6-diaminoresorcinol or a salt thereof. (3) The composition according to the above (1) or (2), wherein the iron (II) compound is iron (II) chloride or its tetrahydrate, or iron (II) phosphate octahydrate. (4) storing 4,6-diaminoresorcinol or a salt thereof in the presence of an iron (II) compound;
A method for preserving and stabilizing 6-diaminoresorcinol or a salt thereof. (5) A polybenzobisoxazole obtained by reacting the composition of any of the above (1) to (3) with an aromatic dicarboxylic acid. (6) The polybenzobisoxazole according to the above (5), which has an intrinsic viscosity of 20 dl / g or more. (7) A molded article obtained by molding the polybenzobisoxazole according to (5) or (6).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The DAR-containing composition of the present invention contains DAR and an iron (II) compound.

In the present invention, the DAR can be prepared by a conventional method. For example, JP-A-2-500743, JP-A-7-242604, JP-A-2-136
No. 5,410,083; U.S. Pat.
453,542, JP-T-5-502028, JP-A-1-238561, JP-A-3-24038, and the like.

[0010] The DAR obtained by the above method is usually used as a dihydrochloride.
It is not limited to the dihydrochloride, but may be an inorganic acid salt such as disulfate or diphosphate, or an organic acid salt such as terephthalate or diacetate.

The iron (II) compound used in the present invention is D
It is a reducing agent for preventing the oxidation of AR and stabilizing the storage, and is not particularly limited as long as it is a compound containing iron (II) and has a reducing power. Hydrates, iron (II) chloride anhydride or tetrahydrate, iron (II) fumarate, iron (II) lactate, iron (II) oxalate dihydrate, iron (II) sulfate anhydride and Heptahydrate, iron (II) sulfide, iron (II) phosphate octahydrate and the like.

The compounding amount of the iron (II) compound varies depending on the kind thereof, but is preferably 100 ppm or more, more preferably, 100 ppm or more in terms of iron (II) based on DAR. Is at least 1,000 ppm, particularly preferably at least 2,000 ppm. This compounding amount is 1
When it is less than 00 ppm, the storage stabilizing effect of DAR is not sufficient, and when DAR is used after short-term storage, it may be acceptable, but it is not suitable for long-term storage of several months. The upper limit of the amount is not particularly limited.
The effect is enough if it is added as much as 000 ppm.
Inclusion of more than this not only causes an increase in cost,
A large amount of iron (I) is contained in the phosphoric acid waste liquid generated in the PBO molding process.
I) Many unfavorable points such as contamination of compounds.

The iron (II) compound is added to the DAR,
Alternatively, it is added during the DAR manufacturing process. It is necessary to add these iron (II) compounds evenly and uniformly. For this purpose, a method of dissolving an iron (II) compound in a solvent such as hydrochloric acid and spraying it onto a DAR and then drying to remove the solvent, or a method of melting the iron (II) compound and adding it to the DAR is adopted. Is done. For this reason, it is preferable that the iron (II) compound easily dissolves in hydrochloric acid or the like or has a low melting point. When the iron (II) compound is mixed with the DAR in a solid state, the DAR and the iron (II) compound are not uniformly mixed, resulting in unevenness, and a portion where the storage stability of the DAR is poor may be locally generated. Absent. In the case where the phosphoric acid waste liquid generated in the PBO molding step is reused, it is preferable that the phosphoric acid waste liquid does not contain sulfur, an organic substance, or the like, which may inhibit the polymerization of PBO. Considering these facts, among the above-mentioned iron (II) compounds, iron (II) chloride and its tetrahydrate and iron (II) phosphate octahydrate can be suitably used. The iron (II) compound is preferably in the form of a hydrate because it dissolves uniformly in the solvent as well as is rapidly dissolved.

As described above, the presence of the iron (II) compound prevents DAR from oxidation and stabilizes storage. By reacting such DAR with an aromatic dicarboxylic acid as a raw material of PBO, PBO having a high degree of polymerization can be obtained. Its intrinsic viscosity is 20 dl / g or more, especially 25 dl / g
g or more, and the upper limit thereof is not particularly limited, but is 45 dl.
/ G.

The aromatic dicarboxylic acids used in the present invention include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenylenedicarboxylic acid and their hydroxyl groups, alkyl having 1 to 4 carbon atoms. And derivatives substituted with an alkoxy or halogen atom having 1 to 4 carbon atoms; and reactive derivatives thereof such as esterified products and acid halides thereof.

The obtained PBO is a homopolymer or a copolymer having a structural unit represented by the following general formula (I).

[0017]

Embedded image

Here, Z in the formula is the following general formula (II)
A divalent aromatic residue represented by (V).

[0019]

Embedded image

Where R ¹ , R ² Represents the same or different and each represents a hydrogen atom, a hydroxyl group, an alkyl having 1 to 4 carbons, an alkoxy having 1 to 4 carbons or a halogen atom.

Hereinafter, a preferred embodiment of the present invention in the production of PBO will be described, but the present invention is not limited thereto. First, DAR (dihydrochloride) is synthesized according to the method described in JP-T-2-500743. This D
The AR solution is sprayed evenly with a hydrochloric acid solution of iron (II) chloride or its tetrahydrate as a storage stabilizer using a spray. Thereafter, by vacuum drying while heating and stirring at 40 to 100 ° C. in a drier, iron (II) chloride or its tetrahydrate is converted to iron (II) in an amount of 100 to 5,000 pp.
A DAR containing m is obtained. In order to check the storage stability of this DAR, PBO was stored at 30 ° C in air for 3 months.
Used for polymerization of

The polymerization of PBO usually has a polymer concentration of 5 to 5.
The used amount of the raw material is adjusted to be 20% by weight. DAR obtained above, micronized terephthalic acid,
H ₃ PO ₄ concentration of 105 to 122% polyphosphoric acid, phosphorus pentoxide, for example, Patent No. such as Wolfe 4,53
By heating and mixing at 70 to 220 ° C. according to the method described in US Pat. No. 3,693, PBO dope with good storage stability, yellow dope color and high polymerization degree can be obtained.

The PBO dope thus obtained is:
It is formed into a desired molded product, for example, a fiber, a film, or the like.
As a method of forming into fibers, for example, the following method is generally used.

The polymer dope of PBO is supplied to the spinning section and discharged from a spinneret into a gas such as air at a temperature of usually 100 ° C. or higher. The discharged dope yarn (yarn before extracting polyphosphoric acid) is taken up at a constant speed by a stress isolation device such as a godet roll and stretched in a gas such as air. The dope yarn solidified by cooling after discharge is guided to an extraction bath using an aqueous or alcoholic solution. The yarn that has passed through the extraction bath passes through the godet roll, and finally contains 1.0% or less of polyphosphoric acid contained in the yarn in the extraction bath.
Washing is preferably performed until the concentration becomes 0.5% or less. Further, the fiber bundle is neutralized with an aqueous alkali solution such as sodium hydroxide,
Wash with water. After such treatment, drying is performed by a dryer using hot air or the like. The single fibers constituting the fiber bundle thus obtained have a sufficient strength of 35 g / d or more and a sufficiently high elastic modulus of about 1000 g / d or more.

As a method of forming into a film, for example,
The following method is common. PBO polymer dope
Extruded with a T-die, this highly viscous film dope
Is cast on a metal roll and cooled. This film
Both sides with unstretched polyethylene terephthalate film.
After laminating the surface, it is stretched in
The lentephthalate film is peeled off. The resulting file
After the solid dope is washed with water and solidified, it is heat-
Get The film thus obtained has a surface smoothness,
Good slipperiness and scratch resistance.
00kg / mm ^TwoWith high tensile modulus
is there.

In the present invention, since an iron (II) compound is used as a storage stabilizer for DAR, the phosphoric acid waste liquid generated in the PBO molding step does not contain heavy metals which are not preferable for the environment. Accordingly, such a phosphoric acid waste liquid can be discarded without imposing an impact on the environment, and the waste liquid can be regenerated into polyphosphoric acid and used again as a PBO production solvent, or can be reused for other uses.

[0027]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the examples.

1. Intrinsic viscosity of PBO Dissolve PBO dope in methanesulfonic acid; B. R
oitman et al. (Macromolecules)
1993, 26 , 5174-5184).
It was obtained by measuring at ° C. 2. Measurement of iron (II) content in DAR This was obtained by generating a chelate ion of iron-phenanthroline and measuring its absorbance at 510 nm. 3. Decomposition degree of DAR DAR is dissolved in an aqueous HCl solution degassed with nitrogen,
It was obtained by measuring the absorbance at 320 nm specific to the decomposition product.

Example 1 6.5 g of iron (II) chloride tetrahydrate was dissolved in 20 ml of an aqueous hydrochloric acid solution. On the other hand, DAR was synthesized according to the method described in Japanese Patent Publication No. Hei 2-500743, and the above-mentioned iron chloride solution was evenly sprayed on 1,000 g of the DAR by spraying. Thereafter, the resultant was dried under reduced pressure while stirring with a rotary evaporator. During drying, the temperature was kept at 40-100 ° C. After drying, the amount of iron (II) in the DAR was measured by absorbance.
It was 1800 ppm. After storing the above DAR at 30 ° C. in the air for 3 months, and measuring the degree of decomposition,
0.0%.

Example 2 6.0 g of iron (II) phosphate octahydrate was dissolved in 20 ml of aqueous hydrochloric acid. This solution was treated with D in the same manner as in Example 1.
AR was sprayed and dried with an evaporator. After drying, D
When the amount of iron (II) in AR was measured by absorbance, 200
It was 0 ppm. After storing the above DAR at 30 ° C. in the air for 3 months, the degree of decomposition was 0.0%.

EXAMPLE 3 4,6-Diaminoresorcinol terephthalate (DAR / T) was prepared by the method described in US Pat. No. 5,276,128.
A) was synthesized, and the same iron (II) chloride as in Example 1 was added thereto.
An aqueous solution of hydrochloric acid of tetrahydrate was evenly sprayed using a sprayer and dried with an evaporator. After drying, the amount of iron (II) was measured by absorbance and found to be 2200 ppm.
After the above DAR / TA was stored in the air at 30 ° C. for 3 months, the degree of decomposition was 0.0%.

Example 4 PBO was polymerized using the DAR obtained in Example 1.
Example 4 After adding 14.49 kg of diphosphorus pentoxide to 43.86 kg of 116-117% polyphosphoric acid under a nitrogen stream.
DAR containing 1800 ppm of iron (II) obtained in
10 kg and 7.10 kg of terephthalic acid pulverized to an average particle size of 2 μm and pulverized were added, and 80 g in a tank reactor was added.
Stir and mix at ° C. Further, the mixture was stirred and mixed at 150 ° C. for 10 hours, oligomerized, and then polymerized using a twin screw extruder heated to 200 ° C. to obtain a polymer dope of PBO. The polymer dope has a yellow color and an intrinsic viscosity of 38.
dl / g.

Example 5 Using the DAR obtained in Example 2 as in Example 4,
BO was polymerized. The color of the obtained polymer dope was yellow, and the intrinsic viscosity was 45 dl / g.

Example 6 DAR / TA obtained in Example 3 was 13.1 kg, 11
63.3% polyphosphoric acid 43.3kg, diphosphorus pentoxide 15.0k
g was weighed in a tank reactor and mixed with stirring at 80 ° C. Further, the mixture was stirred and mixed at 150 ° C. for 10 hours, oligomerized, and then polymerized using a twin screw extruder heated to 200 ° C. to obtain a polymer dope of PBO. The color of the polymer dope was yellow, and the intrinsic viscosity was 43 dl / g.

Example 7 The dope obtained in Example 4 was maintained at a temperature of 170 ° C.
The liquid is sent from an extruder to a gear pump, spun out from a spinneret having 668 holes at 170 ° C., and the discharged yarn is cooled using cooling air at a temperature of 60 ° C., and then brought into contact with a phosphoric acid solution. I took it. The yarn thus obtained is washed until the polyphosphoric acid content becomes 0.5%,
After neutralization with aqueous sodium hydroxide solution, further washing
Dried at 00 ° C. The obtained yarn had a strength of 38 g / d and an elastic modulus of 1034 g / d.

Example 8 The polymer dope of PBO obtained in Example 4 was passed through a filter having a nominal opening of 20 μm, and then passed through a T-die to a depth of 150 μm.
The extruded high-viscosity film-shaped dope was cast on a metal roll in a clean room in a nitrogen atmosphere and cooled. This film-shaped dope was laminated on both sides with a separately prepared unstretched polyethylene terephthalate film. The whole laminate of the dope and the unstretched polyethylene terephthalate film was stretched three times in a transverse direction at 100 ° C. with a tenter, and the laminated polyethylene terephthalate film was peeled off and removed. The obtained film-shaped dope was washed and solidified with a fixed length width while holding both ends, and then, while holding both ends with a tenter, 2
It was heat-set at 80 ° C. to obtain a 3 μm thick PBO biaxially oriented film. The resulting film has good surface smoothness,
Also, the slip property and the scratch resistance were good. The tensile modulus was 2000 kg / mm ² or more.

COMPARATIVE EXAMPLE 1 DAR synthesized by the method described in Japanese Patent Publication No. 2-500743 was stored in the air at 30 ° C. for 3 months without adding a reducing agent. 4.0% when measured
Met. The color of the PBO polymer doped in the same manner as in Example 4 was purple, and the intrinsic viscosity was 15 dl / g.

Comparative Example 2 In place of iron (II) chloride tetrahydrate in Example 1, P
After the addition of d and storage in air at 30 ° C. for 3 months, the degree of decomposition was 3.8%. The color of the polymer dope obtained by polymerization in the same manner as in Example 4 was purple, and the intrinsic viscosity was 13 dl / g.

[0039]

As is apparent from the above description, according to the present invention, the same effect as that of the conventional tin compound was obtained on the storage stability of 4,6-diaminoresorcinol. Further, since heavy metals such as tin are not contained in the phosphoric acid waste liquid generated in the PBO molding process, not only is disposal possible without imposing a large burden on the environment,
The phosphoric acid waste liquid is regenerated into polyphosphoric acid and reused again as a PBO production solvent, or easily reused for other uses, and it is economically advantageous in the production of polybenzobisoxazole, contributing to the industry. It is big to do.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4F071 AA58 AA88 AB15 AB25 AC12 BC01 BC07 4H006 AA01 AA02 AA03 AB46 AD33 BE62 BJ50 BN30 BU46 4J043 PA02 QB15 QB34 RA52 SA06 SA71 TA06 TA12 TA26 TA41 TA66 UA121 VA122 UA122 UA122 VA012 UA122 UA122 XA35 ZB04 ZB11

Claims (7)

[Claims] 1. A composition comprising 4,6-diaminoresorcinol or a salt thereof and an iron (II) compound. 2. An iron (II) compound is added to 4,6-diaminoresorcinol or a salt thereof in an amount of 10% in terms of iron (II).
The composition according to claim 1, which is contained in an amount of 0 ppm or more. 3. The method according to claim 1, wherein the iron (II) compound is iron (II) chloride or tetrahydrate thereof, or iron (II) phosphate octahydrate. Composition. 4. A method for preserving and stabilizing 4,6-diaminoresorcinol or a salt thereof, comprising storing 4,6-diaminoresorcinol or a salt thereof in the presence of an iron (II) compound. 5. A polybenzbisoxazole obtained by reacting the composition according to claim 1 with an aromatic dicarboxylic acid. 6. The polybenzobisoxazole according to claim 5, wherein the intrinsic viscosity is 20 dl / g or more. 7. A molded article obtained by molding the polybenzobisoxazole according to claim 5 or 6.