JPH0364533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel method for producing a copolyester having high elastic modulus and high strength. Since the copolymerized polyester thus produced forms thermotropic liquid crystals, it is easy to mold and can be commercialized as molding materials, films, and fibers.

[Conventional technology]

In recent years, there has been an increasing demand for materials with excellent rigidity, heat resistance, and chemical resistance, whether fibers, films, or molded products. Polyester has come to be widely accepted for use in general molded products, but many polyesters have poor flexural modulus and bending strength, so they are not suitable for applications that require high modulus of elasticity and high strength. In order to improve this mechanical property, it is known to blend reinforcing materials such as calcium carbonate and glass fiber, but this increases the specific gravity of the material, which reduces the lightweight advantage of plastic. During molding, the molding machine is subject to severe wear and there are many practical problems.

In recent years, liquid crystalline polyester has attracted attention as a polyester that does not require a reinforcing material and is suitable for applications requiring high elastic modulus and high strength. The Journal of Polymer Science and Polymer Science has attracted particular attention.
Chemistry Edition Volume 14 (1976) 2043
This was after W.J. Jackson published a thermal liquid crystal polymer consisting of polyethylene terephthalate and acetoxybenzoic acid in pages 1 and 18016/1983. Among these, Jackson claims that this liquid crystal polymer has a rigidity more than five times that of polyethylene terephthalate.
It was reported that it exhibited more than 4 times the strength and 25 times more impact strength, demonstrating new possibilities for high-performance resins.

On the other hand, we first write the general formula (A) [In the formula, R ¹ is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or/and a divalent aliphatic group having 1 to 40 carbon atoms. group (however, 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), and 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 aromatic group having 6 to 20 carbon atoms forming an aromatic ring. 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 having 1 to 4 carbon atoms, or an alkoxy group), or a divalent polyalkylene oxide with a molecular weight of 80 to 8000 The raw material oligoester or polyester consisting of repeating units represented by [representing a radical] is 5 to 95 mol% in terms of the amount of repeating units constituting these, and the general formula
(B) HO−R ³ COOH ... (B) [In the formula, R ³ is a divalent aromatic group having 6 to 20 carbon atoms that forms an aromatic hydrocarbon group (however, the hydrogen of the aromatic hydrocarbon group Atom is halogen atom, carbon number 1~
4, which may be substituted with an alkyl group or an alkoxy group]
5 mol% is reacted to produce a copolymerized oligomer (first step), then an acylating agent is added to perform acylation (second step), and polymerization is further carried out under reduced pressure (third step). (Japanese Patent Application No. 59-42266, Japanese Patent Application No. 59-101572).

In addition, a method has been filed in Japanese Patent Application No. 60-20761 for increasing the polymerization rate and significantly reducing the amount of sublimate, but the copolyester produced in this way did not have sufficient thermal stability. .

[Purpose of the invention]

In view of these points, we have carefully considered the following:
We have discovered a method for producing copolyester with good thermal stability.

That is, the present invention provides a method for producing a copolymerized polyester comprising the three steps described above, namely, the first step of producing a copolymerized oligomer, the second step of adding an acylating agent to perform acylation, and the third step of further polymerizing under reduced pressure. Before the end of the second step, the diol represented by the general formula (C) HOR ⁴ OH ... (C) (in which R ⁴ has the same meaning as R ¹ in the general formula (A)) is added to (B). A method for producing a copolyester characterized by adding 1 to 40 mol % of the amount of the copolyester and reacting it.

[Structure of the invention]

The present invention will be explained in further detail.

The copolyester produced by the conventional method is contained in the oligoester produced in the first step. (In the formula, R ² and R ³ are in formulas (A) and (B)
Since a ^{unit represented} by
There is an excess of COOH groups at the end. Therefore, in addition to OH groups, COOH groups in the copolymer react with acylating agents to form acid anhydride bonds, and terminal carboxylic acids may remain in the final copolymerized polyester, resulting in the copolymerization. It is thought that polyester has become unstable to heat.

Therefore, in the present invention, the excess -COOH group is removed by adding a diol represented by the general formula (C) equivalent to or more than the excess -COOH group, and then the second step of acylation is performed or the acylation It has now become possible to produce a copolymerized polyester with excellent thermal stability by adding a diol while carrying out the above steps and carrying out a polycondensation reaction under reduced pressure.

The present invention is carried out by reacting a polyester or oligoester represented by the general formula (A) with an oxycarboxylic acid to form a copolymerized oligomer, followed by acylation and further polymerization under reduced pressure. In order to produce polyester or oligoester represented by formula (A), carboxylic acid represented by general formula (E) HOOCR ¹ COOH ... (E) (wherein R ¹ has the same meaning as in general formula (A) ) and their esters are used; examples of carboxylic acids 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,
Examples include azelaic acid, suberic acid, dodecane dicarboxylic acid, 3-methyl azelaic acid, glitaric acid, succinic acid, cyclohexane 1,4 dicarboxylic acid, cyclohexane 1,3 dicarboxylic acid, and cyclopentane 1,3 dicarboxylic acid. These may be used as a mixture, and any of those represented by the general formula (E) can be used.

Also, specific examples of diols represented by general formula (F) used to produce general formula (A) HOR ² OH ... (F) (wherein R ² has the same meaning as in general formula (A)) Examples 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, cyclobenpentane 1,3-diol, diethylene glycol, polyethylene glycol, hydroquinone,
Examples include resorcinol, bisphenol A, methylhydroquinone, chlorohydroquinone, and 2,6-naphthalene diol, but these may be used in combination, and any of those represented by general formula (F) can be used. be.

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

Examples of the oxyacid of formula (B) include parahydroxybenzoic acid, 4-hydroxy3-chlorobenzoic acid, metahydroxybenzoic acid, 4-hydroxy3,5-dimethylbenzoic acid, 2-oxy6-naphthoic acid, and 1-hydroxybenzoic acid.
Examples include oxy-5-naphthoic acid, 1-hydroxy-4-naphthoic acid, Schulinger's acid, vanillic acid, and 4-hydroxy-3-methylbenzoic acid. Although it is preferable to use parahydroxybenzoic acid alone in order to maintain melt anisotropy, any oxycarboxylic acid represented by the general formula (B) can be used, or a mixture of these can be used. I don't mind.

In addition, the reaction between the oxycarboxylic acid (B) and the polyester and oligoester represented by the general formula (A) is
carried out at 200-350°C, preferably 220-300°C,
The reaction is carried out for a period of 5 minutes to 10 hours, preferably 20 minutes to 5 hours.

The reaction is carried out until the remaining amount of the oxycarboxylic acid compound is generally 70 mol% or less, preferably 50 mol% or less, particularly preferably 40 mol% or less, based on the charged amount.

Although the reaction can be carried out without a catalyst, it can be carried out with the addition of a catalyst if necessary.

As the diol (C) used in the present invention, any of those represented by the general formula (C) can be used, but
Specific examples include hydroquinone, resorcinol, methylhydroquinone, chlorohydroquinone, acetylhydroquinone, acetoxyhydroquinone, nitrohydroquinone, dimethylaminohydroquinone, 1,4-dihydroxynaphthol,
1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, 2,7-dihydroxynaphthol, 2,
2'-bis(4-hydroxyphenyl)propane,
2,2'-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2'-bis(4-hydroxy3,5-dichlorophenyl)-propane,
2,2'-bis(4-hydroxy-3-methylphenyl)-propane, 2,2'-bis(4-hydroxy-3-chlorophenyl)propane, bis(4-
hydroxyphenyl)-methane, bis(4-hydroxy-3,5-dimethylphenyl)-methane,
Bis(4-hydroxy-3,5-dichlorophenyl)-methane, bis(4-hydroxy-3,5-
dibromophenyl)-methane, 1,1-bis(4
-hydroxyphenyl)cyclohexane, 4,
4'-dihydroxydiphenylbis(4-hydroxyphenyl)-ketone, bis(4-hydroxy-
3,5-dimethylphenyl)-ketone, bis(4
-hydroxy-3,5-dichlorophenyl)-ketone, bis(4-hydroxyphenyl) sulfide, bis(4-hydroxy-3-chlorophenyl) sulfide, bis(4-hydroxyphenyl) sulfone, bis(4- Hydroxy-3,5-
dichlorophenyl) ether, and the like.

The compound represented by formula (C) may be added at any time before the completion of the second stage, but it is particularly preferably added after the completion of the first stage reaction.

The amount of the compound represented by the general formula (C) is preferably 1 to 40 mol% of the amount of the hydroxycarboxylic acid (B), and in particular, as mentioned above, the formation of the unit (D) causes an excess of COOH groups. It is preferable to use the equivalent amount or more. The amount can be ascertained in advance by analyzing the reaction solution at the end of the first stage.

If it is less than 1 mol% of (B), the terminal COOH group will still be excessive and the purpose will not be achieved, which is not preferable.
If the amount exceeds 40 mol%, sublimation will increase, which is not preferable.

It is not preferable to add (C) after the completion of the second stage acylation because it has adverse effects such as a decrease in the polymerization rate and the occurrence of sublimation.

As for the addition method, it may be added in bulk,
It may be added after being diluted with a diluent.

The second step, acylation, is carried out using an acylating agent (acylating agent)/{(B)+2(C)} of 1.0 times or more, preferably 1.2 times or more in mole; The dripping time is at least 10 minutes, preferably
Conducted over 20 minutes. Contact with acylating agent is 80
It is carried out at a temperature of ℃~350℃, preferably 100℃~
carried out at 300°C, more preferably between 120°C and 260°C,
Pressure may be applied.

Alternatively, acylation may be carried out by lowering the temperature of the system to a temperature below the boiling point of the acylating agent. The reaction is carried out for 10 minutes or more to 10 hours, preferably 20 minutes or more to 5 hours.

The diol of general formula (C) may be added before this acylation is completed.

In addition, acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride, etc. are used as acylating agents, but any commonly used acylating agent can be used, and among them, reactivity and cost are From this point of view, acetic anhydride is a typical example.

Next, the third stage of polymerization is carried out at 200°C to 350°C, preferably 220°C to 330°C. In this case, it is preferable to gradually reduce the pressure at the beginning, and if the pressure is gradually reduced from 760 mmHg to 1 mmHg. The time required for this is 30 minutes or more, preferably 60 minutes or more, and it is particularly important to gradually reduce the pressure from 10 mmHg/minute to 1 mmHg/minute.

The second and third stages can also be carried out without a catalyst, but may be carried out in the presence of a catalyst if necessary.

Catalysts used in the first, second and third stages include transesterification catalysts, polycondensation catalysts,
An acylation catalyst and a decarboxylic acid catalyst are used, and these may be used in combination. The amount used is preferably 5 to 50000 ppm based on the polymer.
It is 50-5000ppm.

Also, ηinh is phenol and tetrachloroethane =
Measurement was performed at 30°C at 0.5 g/dl in a 1:1 (weight ratio) mixed solution. ηinh of the final product is 0.3 dl/g or more, preferably 0.35 dl/g or more.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example 1 51.8 g (0.375 mol) of p-hydroxybenzoic acid and 72.1 g of polyethylene terephthalate oligomer (ηinh = 0.12 dl/g) (as the amount of repetition unit) were placed in a glass polymerization tube equipped with a stirring blade, a nitrogen inlet, and a pressure reduction port. 0.375 mol) and 0.037 g of stannous acetate.
Repeat depressurization and nitrogen substitution three times, and finally fill with nitrogen and place under nitrogen flow at a flow rate of 0.5/min.
When the polymerization tube is immersed in an oil bath at 260°C, the contents will melt in about 30 minutes, so start stirring and continue transesterification for 2 hours to produce a copolymerized oligomer.

After that, the temperature was lowered to 140°C in about 30 minutes, 8.25 g (0.075 mol) of hydroquinone was added, and then 67 g (0.657 mol) of acetic anhydride was added dropwise over 30 minutes, and stirring was continued for another 1 hour to perform acylation. .
After that, the temperature of the oil bath was raised to 275℃ over 2 hours, and 0.068g of zinc acetate dihydrate was added.
Apply vacuum gradually. Polymerization was then carried out for 3 hours after a high vacuum of 0.3 mmHg was established. The product is taken out by breaking the glass polymerization tube and turned into chips at 130℃.
Vacuum dry overnight. The obtained polymer was milky white and opaque, and had ηinh=0.76.

Even after further vacuum drying at 120°C for 130 hours, this polymer had excellent thermal stability with ηinh=0.75.

Furthermore, the IR results showed that there was no acid anhydride bond at all.

Example 2 62.2 g (0.45 mol) of p-hydroxybenzoic acid and 57.7 g (0.30 mol) of polyethylene terephthalate oligomer (ηinh = 0.12 dl/g) were added to a glass polymerization tube equipped with a stirring blade, a nitrogen inlet, and a pressure reduction port. 0.036 g of tin was charged, vacuum and nitrogen substitution was repeated three times, and finally the tank was filled with nitrogen and placed under a nitrogen stream at a flow rate of 0.5/min. When the polymerization tube is immersed in an oil bath at 260°C, the contents will melt in about 30 minutes, so start stirring and continue transesterification for 2 hours to produce a copolymerized oligomer. Thereafter, 8.25 g (0.075 mol) of hydroquinone was added, and then 122.4 g of acetic anhydride was added dropwise over 30 minutes, and stirring was continued for an additional hour to effect acylation. The temperature of the oil bath is then raised to 275° C. over 1 hour, 0.068 g of zinc acetate dihydrate is added, and reduced pressure is gradually applied. After a high vacuum of 0.3 mmHg was established, polymerization was carried out for 2 hours. The obtained polymer had ηinh=0.87. Add this polymer to 120
Even after oven drying at ℃ for 130 hours, ηinh＝
It had excellent thermal stability of 0.85.

The IR results showed that there was no acid anhydride bond at all.

Comparative Example 1 Exactly the same as Example 2 was carried out except that hydroquinone was added.

The resulting polymer had ηinh=0.78.

However, when this polymer was vacuum dried at 120°C for 72 hours, the ηinh value decreased significantly to 0.53.

The IR results showed that acid anhydride bonds were present at approximately 10% of the ester bonds.

Example 3 In place of hydroquinone in Example 1, 2,2'-
The same procedure as in Example 1 was carried out except that 25.6 g of bis(4-hydroxyphenyl)propane (bisphenol A) was added.

The resulting polymer has ηinh=0.71 and is dried at 120℃.
It had excellent thermal stability with ηinh=0.70 after 120 hours.

As a result of IR measurement, there was no acid anhydride bond at all.

Example 4 The same procedure as Example 1 was carried out except that hydroquinone was added from the beginning.

The obtained polymer had ηinh=0.72.

〔Effect of the invention〕

As described above, according to the method of the present invention, a copolymerized polyester having excellent thermal stability can be obtained.

Claims (1)

[Claims] 1 General formula (A) [In the formula, R ¹ is a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or/and a divalent aliphatic group having 1 to 40 carbon atoms. 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 having 1 to 4 carbon atoms, or an alkoxy group), and R ² is a group having 2 to 40 carbon atoms. divalent aliphatic hydrocarbon group, divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, divalent aromatic hydrocarbon group having 6 to 20 carbon atoms forming an aromatic ring (however, 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),
or a polyalkylene oxide divalent radical with a molecular weight of 80 to 8,000] is 5 to 95 mol% based on the amount of the repeating units constituting the raw oligoester or polyester.
and the general formula (B) HO−R ³ COOH ...(B) [In the formula, R ³ is a carbon number of 6 to
20 (however, the hydrogen atom of the aromatic hydrocarbon group is a halogen atom, and the number of carbon atoms is 1 to 1)
Hydroxycarboxylic acid 95-5, which may be substituted with an alkyl group or an alkoxy group in 4
From 3 steps: reacting mol% to make a copolymerized oligomer (first step), then adding an acylating agent to perform acylation (second step), and further polymerizing under reduced pressure (third step). In the reaction, the second
Before the end of the step, the diol represented by the general formula (C) HOR ⁴ OH ... (C) (wherein R ⁴ has the same meaning as R ¹ in the general formula (A)) is added in an amount of 1 to 1 of the amount of (B). A method for producing a copolyester characterized by adding 40 mol% and reacting. 2. The manufacturing method according to claim 1, wherein 60% or more of R ¹ in formula (A) is a 1,4-phenylene group. 3. The manufacturing method according to claim 1, wherein in formula (A), ^R2 is an aliphatic hydrocarbon group having 2 to 6 carbon atoms. 4. The manufacturing method according to claim 1, wherein R ¹ in formula (A) is a 1,4 phenylene group. 5. The production method according to claim 1, wherein in formula (A), R ² is an aliphatic hydrocarbon group having 2 carbon atoms. 6. The manufacturing method according to claim 1, wherein R ³ in formula (B) is a 1,4 phenylene group.