JPH0627184B2 - Method for producing copolyester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing a copolyester having a high elastic modulus and a high strength. The copolyester produced in this manner forms a thermotropic liquid crystal, and is therefore easily molded and can be commercialized as a molding material, a film, or a fiber.

[Conventional technology]

In recent years, regardless of whether it is a fiber, film or molded product,
There is a strong demand for materials with excellent rigidity, heat resistance and chemical resistance. Polyester has been widely recognized as a general molded product, but since many polyesters have poor flexural modulus and flexural strength, they have not been suitable for applications requiring high elastic modulus and strength. In order to improve this mechanical physical property, a method of blending a reinforcing material such as calcium carbonate or glass fiber is known, but since the specific gravity of the material becomes large, the advantage of the lightweight characteristic of plastic is reduced, and further At the time of molding, the molding machine is heavily worn and there are many practical problems.

In recent years, liquid crystalline polyester has been attracting attention as a polyester suitable for applications requiring a high elastic modulus and high strength without requiring a reinforcing material. Especially, it has been attracting a lot of attention that Journal of Polymer Science Polymer Chemistry Edition 14 (1976) p. 2043 and Japanese Patent Publication No. 56-1801.
This is because WJ Jackson published a thermal liquid crystal polymer composed of polyethylene terephthalate and acetoxybenzoic acid in JP-A-6. Among them, Jackson said that this liquid crystal polymer has a rigidity 5 times or more that of polyethylene terephthalate.
It was reported that it exhibits more than double the strength and more than 25 times the impact strength, and shows a new possibility for high-performance resins.

However, since this liquid crystalline polymer uses P-acetoxybenzoic acid, the monomer cost is high, and since acetic acid is distilled out during the polymerization, a reactor made of a special material such as titanium is required. Inevitably, the drawbacks that lead to higher costs in terms of both product and product are inevitable. In addition, there is a defect that insoluble and infusible particles (different polymer) are present in the produced polymer.

[Object of the Invention]

In view of such a point, the present inventors have conducted diligent studies, and as a result, a polymer showing melt anisotropy (that is, showing a thermotropic liquid crystal) is obtained by using a hydroxy group without using an acetoxy compound as in the conventional method. We have found a way to make directly from compounds. According to this method, the monomer cost can be drastically reduced, there is no problem with the materials that are normally used for the reactor, the cost can be reduced from the aspect of the equipment, and insoluble and infusible particles (heterogeneous (Polymer) does not exist, the polymerization rate is high, and a polymer having a high degree of polymerization can be easily obtained.

Incidentally, in JP-A-52-26593, it has been found that a titanium-based catalyst is used to directly produce a hydroxy compound, but it is difficult to obtain a polymer having high rigidity by this method.

[Structure of Invention]

The gist of the present invention is the general formula (A) [In the formula, at least 60 mol% or more of R ¹ is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms in which carbonyl bonds are separated by at least 4 or more carbon atoms, and 40 mol% or less Is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a carbonyl bond separated by 3 or less carbon atoms, or
And a divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group). May be). R ² is a divalent aliphatic hydrocarbon group having 2 to 40 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and a divalent aliphatic group having 6 to 20 carbon atoms forming an aromatic ring. Aromatic hydrocarbon group (however, the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms), or a polyalkylene oxide having a molecular weight of 80 to 8000. A divalent group is shown. ]
The starting oligoester or polyester formed from the dicarboxylic acid consisting of the repeating unit of ## STR3 ## and the diol is 5 to 95 mol% in terms of the amount of the repeating unit constituting these, and the hydroxycarboxylic acid represented by the general formula (B) HO-R ³ COOH ... (B) [wherein R ³ has the same meaning as R ¹ in the formula (A) above] is reacted with 95 to 5 mol% to form an oligomer, and then as a catalyst. A method for producing a melt-anisotropic polyester is characterized by producing a melt-anisotropic copolyester by polymerizing in the presence of a tin compound.

The melt-anisotropic copolymerized polyester of the present invention is polymerized after reacting a polyester or oligoester with an oxycarboxylic acid to form an oligomer. Such polymerization is carried out by using aromatic hydroxy group terminals and aromatic carboxyl groups. It is necessary to react the ends, and when a catalyst generally used for the polymerization of polyester is used, the reaction progresses slowly and the degree of polymerization does not increase, or even if polymerized, there is much sublimation of hydroxycarboxylic acid in the polymer. Since it does not enter, it is difficult to produce a melt anisotropic polyester, but by using a tin compound as a catalyst, it is possible to easily produce a melt anisotropic copolyester having a high degree of polymerization and a high polymerization rate.

When the polyester or oligoester is reacted with an oxycarboxylic acid to form an oligomer, the temperature is 2
It is carried out at 00 to 300 ° C. for 15 minutes to 5 hours, and the polymerization is carried out at 240 to 350 ° C., preferably 250 to 330 ° C. for 0.5 hours to 15 hours under high vacuum. In the reaction, the residual amount of the oxycarboxylic acid compound is relative to the charged amount,
It is carried out until it is usually 70 mol% or less, preferably 50 mol% or less, particularly preferably 40 mol% or less.

Next, the production method will be described in more detail. The raw material polyester or oligoester represented by the general formula (A) is used. The carboxylic acid HOOCR ¹ COOH (F) represented by the general formula (F) and its ester are used for producing Examples of carboxylic acids are terephthalic acid, methoxyterephthalic acid, ethoxyterephthalic acid, fluoroterephthalic acid, chloroterephthalic acid, methylterephthalic acid, isophthalic acid, phthalic acid,
Methoxyisophthalic acid, diphenylmethane 4,4'-dicarboxylic acid, diphenylmethane 3,3'-dicarboxylic acid, diphenyl ether 4,4'-dicarboxylic acid, diphenyl-
4,4'-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene 1,5 dicarboxylic acid, naphthalene 1,4 dicarboxylic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, dodecanedicarboxylic acid, 3-methyl Examples thereof include azelaic acid, glital acid, succinic acid, cyclohexane 1,4 dicarboxylic acid, cyclohexane 1,3 dicarboxylic acid and cyclopentane 1,3 dicarboxylic acid. These may be mixed and used, and any of those represented by the general formula (F) can be used.

The other raw material component, diol, has the general formula
The diol represented by (G) is used, and HOR ² OH (G) Specific examples thereof include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3 butanediol, 1,4 -Butanediol, neopentyl glycol,
1,6 hexanediol, 1,12-dodecanediol, cyclohexane 1,4 diol, cyclohexane 1,3 diol,
Cyclohexane 1,2-diol, cyclopentane 1,3-diol and the like can be mentioned, but they may be used as a mixture, and any of those represented by the general formula (G) can be used.

As the polyester or oligoester represented by the general formula (A) used in the present invention, any of those represented by the general formula (A) can be used, but polyethylene terephthalate, polybutylene terephthalate and those Are preferred, and polyethylene terephthalate and its oligomers are particularly preferred.

Next, the reaction method will be described. The raw material polyester or oligoester represented by the general formula (A) and the following general formula
An oxycarboxylic acid represented by (B) is brought into contact with HO—R ³ COOH (B) and heated at 150 to 350 ° C. under normal pressure to form a copolymerized oligomer, and then under post-pressurization and further under vacuum. The polymerization is carried out to complete the reaction. It is also possible to share (G) and (F) when making contact with (A) and (B).

As the oxyacid represented by the general formula (B), para-hydroxybenzoic acid, 4-hydroxy-3-chlorobenzoic acid, meta-hydroxybenzoic acid, 4-hydroxy-3,5-dimethylbenzoic acid, 2-oxy6-naphthoic acid, 1-oxy-5-naphthoic acid, 1-hydroxy-4-naphthoic acid, Schuringer acid, vanillic acid, 4-hydroxy-3-methylbenzoic acid and the like can be mentioned. It is preferable to use parahydroxybenzoic acid alone in order to maintain the melt anisotropy, but any of the oxycarboxylic acids represented by the general formula (B) can be used.

The amount of oxycarboxylic acid used is (B) / (A) + (B)
95 mol%, preferably 30 to 80 mol%, when (F) or (G) is shared, (B) / (A) + (F) + (B), (B) / (A) +
5-9 as (G) + (B) or (B) / (A) + (F) + (G) + (B)
It is 5 mol%, preferably 30 to 80 mol%.

Specific examples of the tin compound as the catalyst include n-butylstannoic acid, methylstannoic acid, isopropylstannoic acid, and 2
Ethylhexylstannoic acid, phenylstannoic acid, nonylphenylstannoic acid, n-dodecylstanonic acid, p-
Chlorophenyl stannonic acid, p-nitrophenyl stannonic acid, p-tolyl stannonic acid, p-anisyl stannonic acid, di-n-butyltin oxide, dimethyltin oxide, di-n-hexyltin oxide, diphenyltin oxide, dinonylphenyls Zoxide, n-butyl, n
-Hexyl tin oxide, diisopropyl tin oxide, di-p-tolyl tin oxide, di-p-nitrophenyl tin oxide, n-butyl hydroxy tin oxide,
Examples include dimethyltin diacetate, tributyltin acetate, stannous acetate, stannous oxalate, dibutyltin dilaurate, dibutyltin malate, tetrabutyltin, and tetrabutoxytin, but any tin compound can be used, especially stannone. Acid compounds and tin oxides [ (R ⁴ , R ⁵ and R ⁶ are each an alkyl group, an aryl group or an aralkyl group)] are preferable in that a high polymer can be easily obtained.

Moreover, these may be mixed and used. The amount used is 1 to 50,000 ppm with respect to all raw materials (number of moles),
It is preferably 10 to 5,000 ppm. Further, such a catalyst, if it is present at the time of polymerization, is added to the copolymer or oligomer when the copolymerized oligomer is produced by the reaction between the oligo or polyester and the oxy acid, or when it is added at the time of the polymerization, a polymer having a high degree of polymerization is added. Is obtained. The inherent viscosity of the obtained polyester is usually 0.2 dl / g or more, preferably 0.3 dl / g or more, more preferably 04 dl / g or more.

〔Example〕

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Ηinh is 0.5 g / dl in a mixed solution of phenol and 1,1,2,2-tetrachloroethane = 1: 1 (weight ratio).
At 30 ° C. The determination of the melt anisotropy was based on the presence or absence of optical anisotropy in the melted state. The apparatus used was a Nikon polarization microscope POH type equipped with a heat stage manufactured by Zeus.

Also, with Intesco's Instron type rheometer, D =
Using a nozzle with a taper of 45 ° at 1.0 mmφ and L = 10 mm, at 240 ° C. with a shear rate of = 1000 sec ^-1 , the fiber was made into a fiber at a withdrawal ratio (λ) = 4, and the elastic modulus (Es) of that fiber Uses Toyo Seiki's Dynamitsu Jiran Tester PMR-5R to determine the polymer density (ρ) to 1.
Determined as 38 g / ml.

Example 1 A glass polymerization tube equipped with a stirring blade pressure reducing port was charged with 77.35 g of p-hydroxybenzoic acid, 46.12 g of polyethylene terephthalate oligomer (ηinh = 0.12 dl / g) and 0.15 g of n-butylstannoic acid, and nitrogen. The exhaust gas replacement is repeated three times, and finally nitrogen is filled and sealed. The polymerization tube is immersed in an oil bath at 248 ° C., and the content melts after 30 minutes, so stirring is started and the acidolysis is continued for 1 hour. Thereafter, the bath temperature is raised to 283 ° C. over 1 hour, and when the bath temperature reaches 283 ° C., a vacuum system is applied, and the inside of the polymerization tube is depressurized to remove it. The pressure in the system was adjusted to 10 mmHg in 1 hour and 30 minutes, and the reaction was continued for 1 hour. Thereafter, the bath temperature is raised to 300 ° C. in 30 minutes, and then the pressure is reduced to 0.3 mmHg in vacuum over 1 hour. The polymerization is continued as it is for 2 hours. After completion of the polymerization, the glass polymerization tube is split and the polymer produced is taken out. This polymer was light brown and opaque and had a value of ηinh of 1.34 dl / g. Observation of this polymer with a polarizing microscope equipped with a hot stage showed 175 ° C.
With the above, flow started and optical anisotropy was exhibited. The sublimation of the monomer to the reduced pressure system was small.

Fiber conversion was performed under the conditions described in the text.
Was 18 GPa.

Examples 2 to 9 Polymerization was performed in the same manner as in Example 1 except that various tin compound catalysts were used instead of n-butylstannonic acid and the polymerization time was changed. The catalyst was used in an amount such that the number of moles of tin atom was the same as in Example 1. The results are shown in Table-1.

Example 10 A polyethylene terephthalate polymer (ηinh = 0.64 dl / instead of the polyethylene terephthalate oligomer)
g) was used and the same reaction as in Example 1 was conducted except that the acidolysis temperature was 275 ° C. ηinh = 0.98 dl / g
A polymer of When the polymer was fiberized under the above conditions, Es was 20 GPa.

Comparative Example 1 Using titanyl potassium oxalate as a catalyst, the reaction was carried out under the same conditions as in Example 1 of JP-A-52-26593 to obtain a polymer having ηinh = 0.50 dl / g. When this polymer was fiberized under the above conditions, Es =
It was 5.5 GPa.

Comparative Example 2 The reaction was performed under the same conditions as in Example 1 except that the catalyst was potassium tininyl oxalate, and ηinh = 0.52 dl / g
A polymer of Furthermore, when this polymer was fiberized under the above conditions, Es was 5.3 GPa.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 61-181825 (JP, A) JP 61-78830 (JP, A) JP 61-14225 (JP, A) JP 60- 245630 (JP, A)

Claims (6)

[Claims] 1. A general formula (A) [In the formula, at least 60 mol% or more of R ¹ is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms in which carbonyl bonds are separated by at least 4 or more carbon atoms, and 40 mol% or less Is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a carbonyl bond separated by 3 or less carbon atoms, or
And a divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group is substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group). May be). R ² is a divalent aliphatic hydrocarbon group having 2 to 40 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and a divalent aliphatic group having 6 to 20 carbon atoms forming an aromatic ring. Aromatic hydrocarbon group (however, the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms), or a polyalkylene oxide having a molecular weight of 80 to 8000. A divalent group is shown. ]
The starting material oligoester or polyester formed from a dicarboxylic acid consisting of the repeating unit of ## STR3 ## and a diol is 5 to 95 mol% in terms of the amount of the repeating unit constituting these, and the hydroxycarboxylic acid represented by the general formula (B) is 95 to 5%.
Mol% HO—R ³ COOH (B) (wherein R ³ has the same meaning as R ¹ in formula (A) above) to form an oligomer, and then as a catalyst. The method for producing a melt-anisotropic polyester, which comprises producing a melt-anisotropic copolymerized polyester by polymerizing in the presence of the tin compound. 2. In the formula (A), 60 mol% or more of R ¹ is 1,4
-The production method according to claim 1, which is a phenylene group. 3. The production method according to claim 1, wherein R ² in the formula (A) is a divalent aliphatic hydrocarbon group having 2 to 6 carbon atoms. 4. The process according to claim 1, wherein R ¹ in the formula (A) is a 1,4 phenylene group. 5. The production method according to claim 1, wherein R ² in the formula (A) is a divalent aliphatic hydrocarbon group having 2 carbon atoms. 6. The method according to claim 1, wherein R ³ in the formula (B) is a 1,4 phenylene group.