JPH062812B2 - Method for producing copolyester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for producing a melt-anisotropic copolymerized polyester, and more specifically, it does not use acetoxybenzoic acid as a raw material monomer, but hydroxybenzoic acid is used. The present invention relates to a method for producing a melt-anisotropic copolymerized polyester, which is low in raw material cost since it is used and the process for isolating acetoxybenzoic acid is omitted, which is very simple in terms of process.

[Prior art]

In recent years, regardless of whether it is a fiber, film or molded product,
There is a high demand for materials with excellent rigidity, heat resistance, and chemical resistance. Polyester has come to be widely accepted for general molded articles, but many polyesters are not suitable for applications requiring high strength because of poor mechanical properties such as flexural modulus. In order to improve this mechanical 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, wear of the molding machine is severe, and there are many practical problems. In recent years, liquid crystalline polyester has been attracting attention as a polyester that does not require a reinforcing material and is suitable for applications requiring high strength. It has become particularly noticeable that WJ J.Jaxon and polyethylene terephthalate and acetoxy benzox have been published in Journal of Polymer Science, Volimer Chemistry Edition, Volume 14 (1976) p. 2043 and Japanese Patent Publication No. 56-18016. This is after the announcement of a thermal liquid crystal polymer consisting of an acid. Among them, Jaxon reported that this liquid crystalline polymer exhibits a rigidity of 5 times or more that of polyethylene terephthalate, a strength of 4 times or more, and an impact strength of 25 times or more, and a new possibility for highly functional resins. showed that.

[Problems to be solved by the invention]

However, although these production methods use acetoxybenzoic acid as a raw material, acetoxybenzoic acid is generally produced by reacting hydroxybenzoic acid with acetic anhydride, followed by isolation and purification. A considerably complicated process is required to obtain acetoxybenzoic acid, and it is not preferable to use acetoxybenzoic acid as a raw material in terms of equipment and cost. In view of such a point, the present inventors have conducted diligent studies and as a result, isolated acetoxybenzoic acid using hydroxybenzoic acid as a raw material without requiring the complicated process as described above.
We have found a method for easily producing a melt-anisotropic polyester without purification.

[Means for solving problems]

That is, the gist of the present invention is the general formula (I) [Wherein R ¹ is a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, a divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms, or 6 to 20 carbon atoms forming an aromatic ring] A divalent aromatic hydrocarbon group (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group), R ² Has 2 carbon atoms
To 40 divalent aliphatic hydrocarbon groups, 4 to 20 divalent alicyclic hydrocarbon groups, and 6 to 2 carbon atoms forming an aromatic ring
A divalent aromatic hydrocarbon group having 0 (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group is a halogen atom, or a carbon number of 1 to 4).
Which may be substituted with an alkyl group or an alkoxy group of), or a divalent group of a polyalkylene oxide having a molecular weight of 80 to 8000]. ^{(II) HO-R 3 -COOH} ......... (II) wherein, R ³ is 6 to 20 carbon atoms to form an aromatic ring 2
A valent aromatic hydrocarbon group (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group)] At least a logarithmic viscosity (ηiηb) is obtained by contacting 95 to 5 mol% of a carboxylic acid in the presence of an acylating agent to form a copolymerized oligomer, followed by polymerization.
Of 0.3 dl / g or more is produced.

Next, the present invention will be described in detail by the general formula (I) shown above.
A poly or oligoester represented by the general formula (I
The reaction is carried out by contacting the hydroxycarboxylic acid represented by I) in the presence of an acylating agent. In this case, i) acylation of the hydroxycarboxylic acid to produce an acyloxycarboxylic acid ii) a poly or oligoester of the acyloxycarboxylic acid 3. Production of copolymerized oligoester by acidolysis iii) Polymerization of oligoester produced by acidolysis consists of three steps, contact with an acylating agent: 80 ° C or higher 3
It is carried out below 00 ° C. When contacting at 150 ° C. or lower, the first-step reaction occurs fairly selectively, but at temperatures higher than that, the reaction of i) and the reactions of ii) and iii) may occur simultaneously. Acidolysis (transesterification reaction)
The second step for carrying out the reaction is 150 to 350 ° C., preferably 200 to 300 ° C. In this case as well, the reaction of ii) may be accompanied by the reaction of iii).

The third step of carrying out the polymerization reaction is carried out at 200 to 350 ° C, preferably 250 to 300 ° C. Further, generally, the reactions of the first step and the second step are carried out under normal pressure or under pressure, and the reactions of the third step are carried out under reduced pressure and under vacuum. Therefore, it is necessary to distill off the carboxylic acid and unreacted acylating agent in the first and second steps. Needless to say, an acylation catalyst, a transesterification catalyst, and a polymerization catalyst may be added if necessary. The molar ratio of the raw material poly or oligoester used in the present invention to the hydroxycarboxylic acid is 5 to 5.
95: 95-5.

The oligoester or polyester composed of the repeating unit represented by the general formula (I) shown above is produced from a dicarboxylic acid and a diol.

As the dicarboxylic acid, a carboxylic acid represented by the general formula (III) HOOCR ¹ COOH ... (III) and its ester are used. Specific examples of the carboxylic acid include 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, dodecane dicarboxylic acid, 3-methyl azelaic acid, glutaric acid, succinic acid, cyclohexane, 1,4 dicarboxylic acid, cyclohexane 1,3 dicarboxylic acid,
Examples thereof include cyclopentane 1,3 dicarboxylic acid, and these may be used as a mixture, and any of those represented by the general formula (III) can be used.

As the diol, a compound represented by the general formula (IV) is used. HOR ² OH ... (IV) Specific examples are ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,12-dodecanediol, 1,3-butadiol, cyclohexane 1,4 diol, cyclohexane 1,3 diol, cyclohexane 1,2 diol, cyclo Pentane 1,3-
Diol, 1,4 cyclohexanedimethanol, p-xylylenediol, 4,4'-thiodiphenol, 4,4'-methylenediphenol, 4,4'dihydroxybiphenyl,
Hydroquinone, resorcinol, 4,4'-sulfonidiphenol, bisphenol A, methylhydroquinone, 2,
6-naphthalene diol, 1,4-naphthalene diol, chlorohydroquinone, 4,4'-cyclohexylidenephenol, diethylene glycol, di-n-butylene glycol, polyethylene glycol, polytetramethylene glycol, etc. are used as a mixture. Alternatively, any of those represented by the general formula (IV) can be used.

As the polyester or oligoester represented by the formula (I) used in the present invention, any of those represented by the general formula (I) can be used, but due to their easy availability, they are polystyrene terephthalate, polybutylene terephthalate and those. Are preferred, and polyethylene terephthalate and its oligomers are particularly preferred.

As the hydroxycarboxylic acid represented by the general formula (II) HO-R ³ -COOH ... (II), para-hydroxybenzoic acid, meta-hydroxybenzoic acid, 2-hydroxy 6-naphthoic acid, 1-hydroxy 5-naphthoic acid 1
-Hydroxy 4-naphthoic acid, 4-hydroxy 3-chlorobenzoic acid, 4-hydroxy 3,5-dimethylbenzoic acid,
Examples thereof include syringer acid, vanillic acid, and 4-hydroxy-3-methylbenzoic acid. Para-hydroxybenzoic acid maintains melt anisotropy and is also preferable for cost reduction, but is represented by the general formula (II). Any of these can be used, and they can also be used as a mixture.

Further, as the acylating agent, acetic anhydride, propionic anhydride, butyric anhydride, benzoic acid anhydride, etc. are used, but any generally usable acylating agent can be used. Acetic anhydride is typical from the viewpoint of cost.

The amount used is usually 0 relative to the hydroxycarboxylic acid.
The amount used is 5 times or more, preferably 0.75 times or more.

Further, the copolymerized polyester according to the present invention may be incorporated with a small amount of a copolymerization component according to various purposes.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

The logarithmic viscosity (ηiηh) is 0.5g /, using a mixed solvent of tetrachloroethane / phenol 1/1 (weight ratio) as the viscosity solution.
It was measured at a concentration of dl at 30 ° C.

The elastic modulus (sonic modulus) is measured by using melt extruded strands with a melt indexer (Takara Kogyo Co., Ltd.) and using a dynamic modular tester-PPM-5R manufactured by Toyo Seiki Co., Ltd. to propagate through the strand polymer. The sound velocity (υ) was measured and calculated from the Laplace's formula shown below.

E = ρυ ² E: Sonicus modula ρ: Density (measured with a density gradient tube) υ: Sound velocity Example 1 Polyethylene terephthalate oligomer (ηiηh 0.10d
l / g) 57.6 g (0.3 mol) and p-hydroxybenzoic acid 6
2.1 (0.45 mol) acetic anhydride 45.9 g and stannous acetate 0.036
g and were charged in a stirring polymerization tube, and after purging with nitrogen three times, the polymerization tube was placed in an oil bath at 150 ° C. and stirred for 1 hour,
1 hour at 170 ℃ while distilling acetic acid, 240 more
Stir at 1 ° C for 1 hour. The temperature of the oil bath was raised to 275 ° C, and the pressure was gradually reduced while distilling out acetic acid.
It was set to mmHg. Next, the polymerization system was returned to normal pressure with N ₂ , 0.066 g of zinc acetate dihydrate was added, and then the mixture was placed under a vacuum of 0.18 mmHg to give 6
Polymerization was completed by stirring for a time.

The ηiηh of this polymer was 0.77 dl / g, and the S. pneumoniae was 2 Gpa.

Example 2 Polyethylene terephthalate polymer (ηiηh = 0.6
4 dl / g) at 240 ° C. for 1 hour at atmospheric pressure, and at 275 ° C. for 1 hour at atmospheric pressure, and under vacuum (0.
Example 1 except that the polymerization was carried out at 275 ° C. for 4 hours at 2 mmHg).
The same reaction as above was carried out to obtain a polymer having ηiηh = 0.61dl / g. This polymer has a sonic module of 14 Gp
It was a.

〔The invention's effect〕

As described above, according to the method of the present invention, a copolyester having excellent physical properties can be obtained by a simplified process.

Claims (1)

[Claims] 1. A general formula (I) [Wherein R ¹ is a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, a divalent aliphatic hydrocarbon group having 1 to 40 carbon atoms, or 6 to 20 carbon atoms forming an aromatic ring] A divalent aromatic hydrocarbon group (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group), R ² is a divalent aliphatic hydrocarbon group having 2 to 40 carbon atoms, 4 to 20 carbon atoms
A divalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms forming an aromatic ring (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group is a halogen atom, It may be substituted with an alkyl group or an alkoxy group having 1 to 4 carbon atoms) or a polyalkylene oxide divalent group having a molecular weight of 80 to 8000]. And the general formula (II) HO-R ³ -COOH (II) [wherein R ³ is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms forming an aromatic ring (provided that the aromatic group is aromatic. The hydrogen atom of the aromatic ring of the group hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group).
95% to 5% by mole of a hydroxycarboxylic acid represented by the formula (9) is contacted in the presence of an acylating agent to form a copolymerized oligomer, and then the polymerization is carried out.
A method for producing a copolyester, which comprises producing a copolyester having an ηh) of 0.3 dl / g or more.