JPH0796611B2 - Ultra high molecular weight polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultra high molecular weight polyester. More specifically, it relates to an ultra-high molecular weight polyester having an intrinsic viscosity of 2.0 or more and good solubility.

[Conventional technology]

Polyesters are usually obtained by directly esterifying an aromatic dicarboxylic acid with a glycol or transesterifying an alkyl ester of an aromatic dicarboxylic acid with a glycol to obtain a glycol ester and / or a low polymer thereof, which is then subjected to high vacuum. It is produced by heating, stirring and polycondensing.

[Problems to be solved by the invention]

The above method of polycondensation by heating and stirring under high vacuum is
At present, it is widely used industrially, but this method requires a vacuum device for maintaining a high vacuum and a high power for stirring a highly viscous substance.

Further, in industrial materials such as tire cords, higher physical properties are required, and therefore high molecular weight polyester is used. Since such a polyester having a higher molecular weight is difficult to stir, a method is generally adopted in which the polymer after melt polycondensation is further solid-phase polymerized in an inert gas stream for a long period of time. However, even in this method, only an intrinsic viscosity of about 1.0 to 1.5 is usually obtained, and it is difficult to completely dissolve it in a solvent.

On the other hand, there is also a report that when a polymer is pulverized into a fine powder and solid-phase polymerized, a polyester having a molecular weight of about 120,000 can be obtained (Cryogenic Properties of Polymers, 249, Dekke
r), in this case, it is stated that it is partially insoluble in the viscosity measuring solvent, and it is presumed that the molecular weight is obviously increased by the crosslinking reaction.

[Means for solving problems]

In order to solve the above problems, the inventors of the present invention have finally made the present invention by diligently, researching and exerting their efforts and completely converting the conventional technical idea. That is, the present invention is a polyester obtained from terephthalic acid or its alkyl ester and ethylene glycol, which has an intrinsic viscosity of 2.0 or more and an insoluble polyester content of 10% by weight or less.

In addition to terephthalic acid or its alkyl ester and ethylene glycol used in the present invention, some of the following components may be contained. Examples of the aromatic dicarboxylic acid or its alkyl ester include aromatic compounds such as isophthalic acid, 5-sodium sulfoisophthalic acid, and 2,6-naphthalene dicarboxylic acid, which have two carboxyl groups directly on the benzene ring or naphthalene ring. , Other ρ-β-oxyethoxybenzoic acid, 4,4'-dicarboxyldiphenyl, 4,4'-dicarboxylbenzophenone, bis (4-carboxylphenyl) ethane or their alkyl esters such as methyl, ethyl and propyl Examples of the alkylene glycol include propylene glycol, butanediol, neopentyl glycol, and other alkylene glycols having 2 to 6 carbon atoms, other diethylene glycol, cyclohexanedimethanol, and ethylene oxide addition of bisphenol A. The thing etc. are mentioned.

The intrinsic viscosity in the present invention is a value obtained by the following method.

Using a mixed solvent of P-chlorophenol / tetrachloroethane (3/1), the intrinsic viscosity measured at 30 ° C.
Converted to phenol / tetrachloroethane (6/4).

[Μ] 60/40 Phenol / TCE = 0.8352 ・ [μ] 3/1 ・ PCP /
TCE + 0.005 Next, as a method for obtaining the ultrahigh molecular weight polyester of the present invention, terephthalic acid or its alkyl ester and ethylene glycol are subjected to an esterification reaction or a transesterification reaction by a conventional method to obtain an oligomer. As it is, or in the presence of the polycondensation catalyst as it is or in the presence of the oligomer which has been initially condensed and the amount of the heat medium and the polycondensation catalyst which are 1 to 100 times, preferably 2 to 10 times the amount of the oligomer, under normal pressure, reduced pressure or pressure.
The polyester of the present invention can be obtained by heating and stirring at 200 to 300 ° C, preferably 220 to 280 ° C for about 1 to 20 hours.
At this time, prior to the polycondensation reaction, an oligomer is first added to a heat medium at a temperature lower than the polycondensation temperature, for example, less than 240 ° C. or the heat medium is added to the oligomer and stirred to form fine particles of the oligomer, and then the heat medium is The temperature may be raised to carry out the polycondensation reaction. During the reaction, the by-product glycol transferred to the heat medium is removed by being accompanied with an inert gas by blowing an inert gas such as nitrogen gas, carbon dioxide gas, helium gas, or argon gas into the reaction system, or It is removed by replacing the heat carrier with a new heat carrier.
The state of the oligomer or polymer in the heat medium is polycondensed in the molten state or the solid state depending on the heating temperature.

As a method other than the above, first, the aromatic dicarboxylic acid or its alkyl ester is subjected to an esterification reaction or a transesterification reaction with glycol by a conventional method to obtain an oligomer, and the obtained oligomer is subjected to a high vacuum by a conventionally known method. After obtaining a polyester having an intrinsic viscosity of 0.5 to 0.7 by employing the method of lower melt polycondensation or the method of polycondensation in the specific heat medium proposed by the inventors, the obtained polyester is then chipped. Then, it is transferred to a solid-state polymerization tank. In the solid phase polymerization tank, the obtained polyester chips and the heat medium are heated at a normal pressure, reduced pressure or pressure of about 150 to 240 ° C., preferably at 210 to 230 ° C. for about 1 to 20 hours under stirring for about 1 to 20 hours to obtain an ultra high molecular weight polyester. Is obtained.

In the above method, the heat medium means a thermally stable organic compound which can be treated as a fluid within the reaction temperature,
There are compounds selected from aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and aromatic ethers. In the present invention, a heating medium which swells polyester but does not dissolve, for example, the following general formula I And one or more compounds represented by II are preferable, and specifically,
Examples thereof include triethylbiphenyl, tetraethylbiphenyl, dimethylbiphenyl, trimethylbiphenyl, tripropylbiphenyl, diethylbiphenyl, cyclohexylbenzene, hydrogenated triphenyl, hydrogenated biphenyl, hydrogenated terphenyl and the like. The heat medium may be purified by a known method, distillation, or the like before use.

In the above method, as the polycondensation catalyst, known catalysts for producing conventional polyesters such as antimony, titanium, germanium, cobalt, manganese, tungsten, and tin compounds can be used, but in the present invention, tungsten soluble in polyester is used. Compounds or tin compounds are preferred, such as tungstic acid or salts thereof, stannous acetate, stannous bromide, stannic bromide, stannous salt,
Examples include stannic chloride.

[Operation] The operation of the present invention is as follows. That is, the polycondensation reaction of the polyester is an equilibrium reaction with the byproduct glycol, and a high molecular weight polymer cannot be obtained unless the byproduct glycol is removed outside the polymer system. It is considered that the heat medium is partially impregnated in the polymer to swell the polymer and the by-produced glycol is extracted from the polymer to promote the polycondensation reaction. The reason why the polyester of the present invention is easily soluble in a solvent despite its high viscosity is unknown.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 An oligomer obtained by direct esterification of terephthalic acid and ethylene glycol (in a catalyst having a 500 ml internal volume, equipped with a stirrer, an inert gas inlet, a gas outlet, and a lower outlet) , Containing 0.05 mol% tungstic acid as tungsten with respect to the acid component and having an intrinsic viscosity of 0.35.) 5 g, and 250 ml of hydrogenated triphenyl as a heat medium, while blowing nitrogen gas at 2.0 l / min, The mixture was kept at 250 ° C and stirred with heating. Waste gas, a part of the heat medium, and by-product ethylene glycol were discharged from the outlet, and a new heat medium was added to keep the liquid surface constant during this period. At the 4th and 6th hours, the entire heat transfer medium was replaced with a new one.

After 8 hours, polyethylene terephthalate was taken out, thoroughly washed with acetone and then dried. The obtained polyester was white, the intrinsic viscosity was 2.3, and the insoluble polyester measured by the above-mentioned measurement method was 0% by weight.

Next, the polymer attached inside the reactor was treated with m-cresol 20.
The intrinsic viscosity of the polyester obtained by dissolving in 0 ml, reprecipitating with methanol, washing, and drying was 2.3.

Example 2 The same method as in Example 1 was carried out except that triethylbiphenyl was used as the heating medium. The intrinsic viscosity of the polymer after reacting for 8 hours was 2.0, and the insoluble polyester was 0% by weight.

Comparative Example Polyester chips obtained by direct esterification of terephthalic acid and ethylene glycol in the same reactor as that used in Example 1 and then ordinary melt polymerization (containing 0.05 mol% antimony as a polymerization catalyst, Intrinsic viscosity is 0.
60. ) Was used to perform crystallization treatment at 150 ° C.
50 g of this polyester chip was placed in a glass tube and kept at 230 ° C. while flowing dry nitrogen at 2.0 l / min.

After 8 hours, the polyester was taken out and the intrinsic viscosity was measured by the same method as in Example 1 and found to be 0.90. The obtained polyester was colored in pale yellow.

Example 3 In a 300 ml separable flask equipped with a stirrer having a turbine type stirring blade, a thermometer, a solvent and inert gas inlet, and a gas outlet, 5 g of the same tungsten-containing oligomer as in Example 1 and heat were added. Medium hydrogenated triphenyl 200m
The solution was put in a flask and kept at a constant temperature of 240 ° C. and reacted with vigorous stirring. In addition, the nitrogen gas heated during this period
While blowing at 2.0 l / min, a new solvent was added so as to keep the liquid surface constant. 8 hours later, cool down,
The polymer was taken out, thoroughly washed with acetone, and then dried. The intrinsic viscosity of the obtained polyester is 3.03,
Insoluble polyester was 0% by weight.

Example 4 The same procedure as in Example 5 was carried out except that 5 g of an oligomer containing stannous acetate in an amount of 0.05 mol% in terms of tin and having an intrinsic viscosity of 0.34 was used as the oligomer. The intrinsic viscosity of the obtained polyester was 3.02, and the insoluble polyester was 0% by weight.

Example 5 The same as Example 5 except that 50 g of the oligomer used in Example 4 and 250 ml of the heat medium hydrogenated triphenyl were placed in a reactor and maintained at 237 ° C. while gradually raising the temperature and polycondensed for 12 hours. The same was done. The intrinsic viscosity of the obtained polyester was 3.03, and the insoluble polyester was 0% by weight.

Example 6 In Example 5, the same reaction as in Example 5 was carried out except that 50 g of the oligomer used in Example 1 was used. The intrinsic viscosity of the obtained polyester was 2.56, and the insoluble polyester was 0% by weight.

Example 7 In Example 5, the reaction was performed in the same manner as in Example 5 except that triethylbiphenyl was used as the heating medium. The intrinsic viscosity of the obtained polyester was 2.79 and the insoluble polyester was 0% by weight.

Example 8 50 g of a molten oligomer obtained in the same manner as in Example 1 (however, containing 0.05 mol% of antimony as a polycondensation catalyst and having an intrinsic viscosity of 0.348) was used as a heating medium at room temperature and 200 ml of triphenyl hydride. When added to and stirred, the mixture solidified to particles having an average particle diameter of 1 to 2 mm, and an oligomer dispersion liquid was obtained. This oligomer dispersion was heated to 200 ° C., heated and stirred for 2 hours, further heated to 235 ° C., and subjected to polycondensation reaction for 20 hours.

The product obtained was cooled to 150 ° C. and then filtered, the polymer was thoroughly washed with acetone and dried. As a result, the obtained polyester was white, the intrinsic viscosity was 2.2, and the insoluble polyester was 0% by weight.

Comparative Example 2 A polyester having an intrinsic viscosity of 0.615 (containing 0.05 mol% of antimony as a polymerization catalyst) obtained by conventional melt polymerization was pulverized to a particle size of about 1.4 to 2.4 mm and depressurized (0.1 Torr).
Under stirring, the mixture was heated and stirred at 215 ° C. After 170 hours, finally the intrinsic viscosity
I got 1.59 polyester, but 1 insoluble polyester
It was also 1.5% by weight.

Reference Examples 1 to 5 The ultrahigh molecular weight polyethylene terephthalate of the present invention shown in Table 1 (Reference Examples 1 to 3) and conventional polyethylene terephthalate (Reference Examples 4 and 5) were dissolved in trifluoroacetic acid / dichloroethane (1/1). And about 4 by solvent casting method
A 0 μ thick film was prepared. The obtained film was stretched in silicone oil at 150 ° C to about 80% of the maximum stretching ratio, and then heat set at 220 ° C for 1 minute. The breaking strength of this stretched film was measured by Tensilon. The results are shown in Table 1.

The maximum draw ratio is 1 cm x 3 cm from the unstretched film.
Was prepared and stretched in silicone oil at 150 ° C., and the maximum stretching ratio was measured.

[Advantages of the Invention] By adopting the ultrahigh molecular weight polyethylene terephthalate of the present invention, it can be expected to have higher physical properties and higher performance in the field of industrial materials such as tire cords and films.

It can be applied to high strength and high physical properties fibers and other molded products.

Since it has good solubility, it can be solution cast into fibers and films.

There are immeasurable future uses in various fields.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 52-85293 (JP, A) JP-A 50-45090 (JP, A) JP-A 49-39694 (JP, A) JP-A 61- 241316 (JP, A) JP 61-103925 (JP, A) JP 61-98728 (JP, A) JP 61-91219 (JP, A)

Claims (4)

[Claims] 1. An ultra high molecular weight polyester which is a polyester obtained from terephthalic acid or its alkyl ester and ethylene glycol and has an intrinsic viscosity of 2.0 or more and an insoluble polyester content of 10% by weight or less. 2. The ultra high molecular weight polyester according to claim 1, which has an intrinsic viscosity of 2.5 or more. 3. The ultra high molecular weight polyester according to claim 1, which has an intrinsic viscosity of 3.0 or more. 4. The ultra high molecular weight polyester according to claim 1, wherein the insoluble polyester is 5% by weight or less.