JPH062813B2 - Method for producing copolyester - Google Patents

Description

The present invention relates to a method for producing a copolyester having a high rigidity and a high breaking elongation.

[Prior art]

In recent years, regardless of whether it is a fiber, film or molded product,
There is a growing demand for materials with excellent rigidity, heat resistance and chemical resistance. Polyester has come to be widely accepted for general molded product applications, but many polyesters
Since it has poor mechanical properties such as flexural modulus, it is not suitable for applications requiring high 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 lightweight which is a 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. No need for reinforcements,
As a polyester suitable for applications requiring high strength, liquid crystalline polyester has recently been attracting attention. It has become particularly popular that Journal of Polymer Science Polymer Chemistry Edition 14 (1976) p. 2043 and Japanese Patent Publication 56.
This is because WJ Jaxon published a thermal liquid crystal polymer composed of polyethylene terephthalate and acetoxybenzoic acid in −18016.

[Problems to be solved by the invention]

This liquid crystalline polymer has a rigidity of 5 times or more that of polyethylene terephthalate and a strength of 4 times or more, but the breaking elongation is very low. In view of such circumstances, the present inventors have conducted diligent studies, and as a result, found a method for producing a copolyester having high rigidity, high strength, large elongation at break and good moldability.

[Structure of Invention]

The gist of the present invention is the general formula (I) [In the formula, R ¹ is an alicyclic hydrocarbon divalent radical having 4 to 20 carbon atoms, an aliphatic hydrocarbon divalent radical having 1 to 40 carbon atoms, or an aromatic having 6 to 20 carbon atoms to form an aromatic ring. Group hydrocarbon divalent radical (provided that the hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, a C ₁ -C ₄ alkyl group or an alkoxy group), and R ² represents the number of carbon atoms. 2-40 aliphatic hydrocarbon divalent radicals, carbon number 4
To 20 alicyclic hydrocarbon divalent radicals, aromatic hydrocarbon divalent radicals 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, C ₁ -C may be substituted with an alkyl group or an alkoxy group of _4), or molecular weight consisting of polyalkylene oxide divalent radical indicates a] of repeating units of 80 to 8,000 raw oligoester or polyester of the general formula (II) HO-R ³ -COOH (II) [wherein, R ³ is an aromatic hydrocarbon divalent radical having 6 to 20 carbon atoms forming an aromatic ring (provided that a hydrogen atom of the aromatic ring of the aromatic hydrocarbon group is present). Represents a halogen atom, or a C ₁ -C ₄ alkyl group or an alkoxy group).
R ⁵ represents an alkyl group] to form a copolymerized oligomer, and then an acylating agent is added to acetylate to carry out further polymerization. At that time, the polymerization temperature is 280 to 35.
It exists in the manufacturing method of the copolyester characterized by performing at 0 degreeC.

Generally, when producing a polyester typified by polyethylene terephthalate, if the polymerization temperature is set to a high temperature, the decomposition reaction is prioritized over the polymerization, so that the degree of polymerization is difficult to increase. Although a method of carrying out polymerization is used, the reaction rate is slow in solid-state polymerization and the process is complicated.

The present invention has a logarithmic viscosity ηinh of 0.85 dl / g without solid phase polymerization.
This is a method for easily producing the above-mentioned copolyester simply by raising the polymerization temperature, which is a method that has never been considered in the conventional wisdom. As described above, the reason why a polymer having a high degree of polymerization is obtained is generally that a monofunctional OH compound, which is a by-product of decarboxylation of an oxycarboxylic acid, is acetylated to form an acyloxy compound (J). Oligomers or polymers in which (J) reacts with the carboxylic acid end of the oligomer or polymer and has R ³ O groups at the ends (K) (K) reacts with the oligomer or polymer (L) having a terminal acetoxy to give a polymer, but the reaction in the final step is 280 to 350 ° C, preferably 285 to 330 ° C.
Therefore, since it is easy to proceed, it is assumed that high ηinh (η ≧ 0.85dl / g) can be easily obtained.

The copolyester of the present invention can be produced by catalytically reacting a polyester or oligoester with an oxycarboxylic acid to form a copolymer oligomer, followed by acetylation and polymerization, and then deacetic acid. In order to describe the production method in more detail, the production method of such a copolyester is generally represented by the general formula:
Raw material polyester or oligoester having a repeating unit represented by (I) The reaction ratio of the raw material polyester or oligoester and the oxycarboxylic acid is 5:95 to 95: 5 in terms of the molar ratio of the former repeating unit (II) and the latter oxycarboxylic acid.
Is.

The carboxylic acid HOOCR ¹ COOH (F) represented by the general formula (F) and its ester are used for producing the starting polyester (I). 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.

Further, specific examples of the diol HOR ² OH represented by the general formula (G) used for producing (I) ... (G) include ethylene glycol, 1,3-propanediol, and 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
Examples thereof include diols, but these 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 formula (I) used in the present invention, any of those represented by the general formula (I) can be used, but polyethylene terephthalate, polybutylene terephthalate and those thereof are easily available. Oligomers are preferable, and polyethylene terephthalate and its oligomers are particularly preferable.

Next, the reaction method will be described. The starting polyester or oligoester represented by the general formula (I) and the oxycarboxylic acid represented by the general formula (II) are converted into HO-R ³ COOH (II) (wherein R ³ Are shown above.) After contacting and heating at 150 to 350 ° C. under normal pressure to form a copolymer oligomer, an acetylating agent is added to effect acetylation and polymerization, and further decompression is performed under reduced pressure. It is carried out by carrying out acetic acid to complete the reaction. It is also possible to share (G) and (F) when making contact with (I) and (II). Further, the polymerization temperature is 280 to 35
It is necessary to carry out at 0 ° C. Especially 290-330
A polymer having a high degree of polymerization can be easily obtained by carrying out at a temperature of ℃.

As the oxyacid represented by the general formula (II), 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 (II) can be used.

The amount of oxycarboxylic acid used is (II) / (I) + (II), (II) /
(I) + (F), (II) / (I) + (G) + (II) or (II) / (I) + (F)
It is 30 to 80 mol% as + (G) + (II). Acetic anhydride is used as a typical acetylating agent, but the acetylating agent is not limited thereto. If necessary, a transesterification catalyst, an acetylation catalyst and a polymerization catalyst may be used.

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

The copolyester obtained in this way has ηinh
It is 0.85 dl / g or more, and there are no insoluble and infusible particles.

Also, with Intesco Instron type rheometer, D = 1.
Using a nozzle with a taper of 45 ° at 0 mmφ and L = 10 mm, at 240 ° C., shear rate (γ ′) = 1000 sec ^-1 withdrawal ratio
Fiber formation was performed at (λ) = 4, and the physical properties were measured. In this case, the melt viscosity was small in spite of the large ηinh, and the fiber could be easily formed. The fiber was measured for elastic modulus and ultimate elongation using a 100 kg Tensilon manufactured by Toyo Baldwin. For the elastic modulus (Es) of the fiber, Toyo Seiki Dynamo Mogillastaster PMR-5R is used.
The ρ (density) of the polymer was determined as 1.38 g / ml.

〔Example〕

Examples will be shown below, but the present invention is not limited to these examples.

Example 1 Polyethylene terephthalate oligomer (ηinh = 0.11d
l / g) 46.12 g (0.24 mol) of para-hydroxybenzoic acid
77.35 g (0.56 mol) and stannous acetate 0.037 g were charged into a polymerization tube equipped with a stirrer, purged with nitrogen three times, and then the polymerization tube was placed at 240 ° C. in an oil bath previously prepared for 30 minutes. After being dissolved, the mixture is stirred at 240 ° C. for 1 hour to carry out acidolysis.

Next, 71.46 g (0.56 mol) of acetic anhydride was added, and the mixture was stirred for 1 hour and 30 minutes while distilling off acetic acid. While the acetic acid was distilled off, the bath temperature was raised from 240 ° C. to 300 ° C. in 30 minutes, and then the pressure was gradually reduced to a vacuum of mmHg to completely distill off the acetic acid. Furthermore, nitrogen was fed into the polymerization tube to return it to normal pressure, 0.064 g of zinc acetate dihydrate was added, and the mixture was stirred under a vacuum of 0.1 mmHg for 6 hours to complete the polymerization.

The ηinh of this polymer was 1.10 dl / g and no insoluble matter was present.

Fiber conversion was performed under the conditions described in the text, and the melt viscosity in that case was 1350 poise, and Es was
51.7GPa, ultimate elongation 5.2%, tensile strength 46.9kg / mm ²
It was.

Example 2 The procedure of Example 1 was repeated except that the acetylation time was changed to 3 hours and the polymerization time was changed to 3.5 hours. As a result, ηinh = 0.93 dl / g polymer was obtained without insoluble matter, and the melt viscosity was 1030 poise, Es = 50.5 GPa, ultimate elongation 3.9%, and tensile strength 46.9 kg / mm ² .

Example 3 61.49 g of polyethylene terephthalate oligomer (0.3
2 mol), 66.30 g (0.48 mol) of para-hydroxybenzoic acid
Was performed in the same manner as in Example 1 except that was used. As a result, a polymer having no insoluble matter and ηinh = 0.87 dl / g was obtained, and the polymer had a melt viscosity of 1030 poise and Es of 36.9.
GPa, ultimate elongation 3.8% and tensile strength 39.3%.

Example 4 53.80 g of polyethylene terephthalate oligomer (0.2
8 mol), hara hydroxybenzoic acid 71.83 g (0.52 mol)
Was performed in the same manner as in Example 1 except that was used. As a result, a polymer having no insoluble matter and ηinh = 1.04 dl / g was obtained. The polymer had a melt viscosity of 1270 poise, Es = 34.2, ultimate elongation of 4.2%, tensile strength of 40.2%, and coefficient of linear expansion of 1 × 10 ^{−. 6} /
It was ℃.

Comparative Example 1 Polyethylene terephthalate (ηinh = 0.64dl / g) 3
8.4 g (0.20 mol) and paraacetoxybenzoic acid 54.1 g
(0.30 mol) was used to carry out polymerization in the same manner as in the method described in Japanese Patent Publication No. 56-18016 (the method of Example 1).
Although a polymer of 0.61 dl / g was obtained, a small amount of insoluble matter was present when ηinh was measured, and the content was filtered and removed. Melt viscosity
150 Poise, Es = 38.7GPa, Ultimate Elongation 1.4%, Tensile Strength 2
It was 9.1 kg / mm ² , and the ultimate elongation was small.

Comparative Example 2 The procedure of Example 3 was repeated except that the polymerization temperature was changed to 275 ° C., and a polymer having no insoluble matter and ηinh = 0.60 dl / g was obtained. The Es was 33.1 GPa and the ultimate elongation was 1.9%, and the ultimate elongation was small.

〔The invention's effect〕

According to the method of the present invention, the rigidity is high, the strength is high, the elongation at break is large, the moldability is good, and the insoluble and infusible particles (different structure)
It is easy to obtain a polymer free from

Claims (1)

[Claims] 1. A general formula (I) [In the formula, R ¹ has 6 to 20 carbon atoms to form an alicyclic hydrocarbon divalent radical having 4 to 20 carbon atoms, an aliphatic hydrocarbon divalent radical having 1 to 40 carbon atoms, or an aromatic ring. Aromatic hydrocarbon divalent radical (provided that the aromatic hydrogen atom of the aromatic hydrocarbon group may be substituted with a halogen atom, a C ₁ -C ₄ alkyl group or an alkoxy group), and R ² is carbon. Aliphatic hydrocarbon divalent radical having 2 to 40 carbon atoms, alicyclic hydrocarbon divalent radical having 4 to 20 carbon atoms, aromatic divalent hydrocarbon radical having 6 to 20 carbon atoms forming an aromatic ring (however, , The hydrogen atom of the aromatic ring of the aromatic hydrocarbon group may be substituted with a halogen atom, a C _{1 to} C ₄ alkyl group or an alkoxy group), or a polyalkylene oxide divalent radical having a molecular weight of 80 to 8000] Raw oligoer consisting of repeating units of Ether or polyester of the general formula (I
Hydroxycarboxylic acid represented by I) HO-R ³ -COOH (II) [In the formula, R ³ is an aromatic hydrocarbon divalent radical 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 aromatic hydrocarbon group is a halogen atom, which may be substituted with a C ₁ -C ₄ alkyl group or an alkoxy group)] to form a copolymerized oligomer, followed by acylation. A method for producing a copolyester, which comprises adding an agent, acetylating, and further polymerizing at a polymerization temperature of 280 to 350 ° C.