JPH05271393A - Production of polyester copolymer - Google Patents

Abstract

PURPOSE:To obtain a polyester copolymer having high degree of polymerization and excellent heat resistance and injection moldability. CONSTITUTION:In producing a polyester copolymer consisting of two glycol components of 1,4-butanediol and 1,4-cyclohexanedimethanol and an acid component of 2,6-naphthalenedicarboxylic acid, first solution polycondensation and/or melt polycondensation is carried out and the prepared polycondensate is further polymerized in a solid phase at >= its melting point to produce a polyester copolymer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester copolymer having excellent heat resistance and injection moldability.

[0002]

2. Description of the Related Art In recent years, plastics have been used in a wide range of fields, and special resins having various physical properties have been actively developed. The main polyester resin is polyethylene terephthalate, which has excellent mechanical properties, electrical properties, chemical resistance, etc. and has a wide range of applications. This polyethylene terephthalate (Japanese Patent Laid-Open No. 63-30
4023) and polybutylene terephthalate (JP-A-1
-126325), a method for producing a polyester polymer having a large degree of polymerization by using a solid phase polymerization method is known, but these resins have a problem that they are not excellent in heat resistance. .. On the other hand, polyethylene cyclohexylene dimethylene naphthalate is known as a resin having high heat resistance (JP-A-1-201325, JP-A-1-20132).
Four).

[0003]

However, the polyethylene terephthalate and polybutylene terephthalate have a problem that they have a low melting point of 230 to 265 ° C. and are not excellent in heat resistance.

Further, the above-mentioned polyethylene cyclohexylene dimethylene naphthalate has not been obtained with a resin having a low intrinsic viscosity and a high degree of polymerization.

An object of the present invention is to provide a method for producing a polyester copolymer having a high degree of polymerization, excellent heat resistance, and applicable to injection moldability and the like.

[0006]

Means for Solving the Problems As a result of earnest studies to achieve the above object, the present inventors have prepared a prepolymer once and then further solid-phase polymerize it to sufficiently increase the degree of polymerization and to improve heat resistance. It was found that a copolymer having excellent properties and applicable to injection moldability can be obtained, and the present invention has been accomplished.

That is, the present invention produces a polyester copolymer in which the glycol component is composed of two components, 1,4-butanediol and 1,4-cyclohexanedimethanol, and the acid component is 2,6-naphthalenedicarboxylic acid. At this time, first, solution polycondensation and / or melt polycondensation is performed, and the obtained polycondensate is further solid-phase polymerized at a temperature below its melting point. ..

The molar ratio of the glycol component in the copolymer is preferably about 1:99 to 99: 1 of 1,4-butanediol: 1,4-cyclohexanedimethanol, and 40:60 to 1: 1.
About 0:90 is preferable. There are cis type and trans type in 1,4-cyclohexanedimethanol, but any of them may be used. It may be a mixture of cis type and trans type, and in that case, the ratio of cis type and trans type does not matter.

As a method for producing this copolymer, similar to the method for producing other polyesters, first, 1,4-butanediol or 1,4-cyclohexanedimethanol glycol and an ester of 2,6-naphthalenedicarboxylic acid are used. The resulting 2,6-naphthalenedicarboxylic acid glycol ester may be subjected to transesterification reaction to cause polycondensation, or may be subjected to direct polycondensation from acid and glycol. The first half of these polycondensation reactions is performed in a liquid state. That is, polycondensation is carried out as a solution by adding a solvent or the like, or polycondensation is carried out by heating and melting so that the resulting polycondensate does not precipitate as a solid, or they are used in combination.

As the transesterification reaction, the following modes are possible. (1) Naphthalenedicarboxylic acid lower alkyl ester and 1,
4-butanediol is reacted, and 1,4-cyclohexanedimethanol is added when the reaction has progressed to some extent, and the reaction is further continued. (2) naphthalenedicarboxylic acid lower alkyl ester, 1,
4-Butanediol and 1,4-cyclohexanedimethanol are charged in advance and the transesterification reaction is performed at once. (3) naphthalenedicarboxylic acid lower alkyl ester and 1,
The transesterification reaction of 4-butanediol and the lower alkyl ester of naphthalene dicarboxylic acid and 1,4-cyclohexanedimethanol are separately carried out, and both are mixed and used at an arbitrary ratio in the polycondensation stage.

The lower alkyl group of the above naphthalenedicarboxylic acid lower alkyl ester may be a C _{1 to} C ₄ group, and is usually a methyl group. The transesterification catalyst may be any one that can be used for the synthesis of polyester such as polyethylene terephthalate and polybutylene terephthalate.
Examples include calcium, manganese, cobalt, zinc,
Examples thereof include alkaline earth metals such as lead, tin and iron, alkoxides such as transition metals, oxides and salts such as acetates. These may be used alone or in combination of two or more. The amount of the catalyst used is about 10 to 1000 mmol% with respect to naphthalenedicarboxylic acid. The temperature of the transesterification reaction is usually about 200 to 300 ° C, preferably 220 to 260 ° C. The reaction time is required to reach a predetermined reaction rate or higher, usually 80% or higher, and the reaction may be performed until the lower alcohol produced as a result of the reaction is almost completely distilled.

The polycondensation reaction is carried out by polycondensing the above transesterification reaction product in the presence of a polycondensation reaction catalyst. This catalyst may be any catalyst that can be used for the synthesis of polyester such as polyethylene terephthalate and polybutylene terephthalate, and alkoxides, oxides, acetates and the like of metals such as titanium, tin, antimony and germanium can be used. The amount of the catalyst used may be about 10 to 1000 mmol% with respect to naphthalenedicarboxylic acid. These may be used alone or in combination of two or more. The polycondensation reaction may be carried out in a separate container after isolating the product of the obtained transesterification reaction once, or may be followed by polycondensation in the container in which the transesterification reaction has been carried out. The polycondensation may be carried out at a pressure of normal pressure to 1 mmHg or lower at about 250 to 320 ° C., and the temperature may be gradually raised.

The polycondensate obtained as described above is then solid-phase polymerized. The solid phase polymerization may be carried out under reduced pressure, under a stream of nitrogen, an inert gas or the like, or in combination thereof. The degree of pressure reduction is preferably 30 mmHg or less, and particularly preferably 1 mmHg or less. The flow rate of the air stream is preferably 1 to 1000 ml / min per 1 g of the condensate. To prevent fusion during solid phase polymerization, even if the reaction liquid is gradually cooled to stop crystallization of the polycondensate production reaction to promote crystallization of the polycondensate, the polycondensate may be formed before the solid phase polymerization starts. May be heated at a temperature below its melting point for several hours for pre-crystallization. The polymerization temperature is not higher than the melting point of the polyester copolymer produced, for example, 10
0 to 400 ° C, particularly 200 to 300 ° C is preferable. A suitable polymerization time is, for example, 5 to 24 hours.

The polymerized form of the polyester copolymer obtained by the method of the present invention may be either random type or block type. As physical properties, the intrinsic viscosity is 0.2 to 1.2 dl / g, the melting point is 200 to 400 ° C, especially 220 to 350 ° C, and the thermal decomposition starting temperature is 33.
0-450 ° C, elongation at break 5-20%, Izod impact strength with notch 1-5 kg · cm / cm ² .

[0015]

【Example】

Measurement method: Intrinsic viscosity: Determined from solution viscosity measured at 35 ° C. in a 2: 3 mixed solvent of 1,1,2,2-tetrachloroethane and phenol. Melting point: Obtained from the melting peak when the sample was heated (10 ° C./min) with a differential scanning calorimeter (DSC). Composition ratio: A polymer sample was hydrolyzed in a basic solution, and each component was quantified by gas chromatography. Elongation at break: Measured according to ASTM D-638. Izod impact strength: measured according to ASTM D-256.

Preparation of Ester Exchanger Preparation Example 1 244 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester,
189 parts of 1,4-butanediol was placed in a reactor equipped with a rectification column, heated and melted at a bath temperature of 190 ° C., then 0.25 parts of titanium tetranormal butoxide was added, and the reaction was carried out while raising the bath temperature to 260 ° C. .. When 64 parts of methanol and 14 parts of 1,4-butanediol were distilled, the reaction was stopped to obtain an ester exchange product consisting of a 2,6-naphthalenedicarboxylic acid component and a 1,4-butanediol component.

Preparation Example 2 244 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester,
Put 289 parts of 1,4-cyclohexanedimethanol (trans isomer / cis isomer = 70/30) into a reactor equipped with a rectification column, and set the bath temperature to 240.
After heating and melting at 0 ° C, 0.24 part of titanium tetra-normal butoxide was added, and the reaction was carried out while raising the bath temperature to 270 ° C. When 64 parts of methanol and 6.4 parts of 1,4-cyclohexanedimethanol were distilled, the reaction was stopped to obtain an ester exchange product consisting of a 2,6-naphthalenedicarboxylic acid component and a 1,4-cyclohexanedimethanol component.

Preparation of Polyester Copolymer Example 1 The transesterification product obtained in Preparation Example 1 was used so that the 1,4-butanediol component was 0.215 mol, and the transesterification product obtained in Preparation Example 2 was used. Put 1,4-cyclohexanedimethanol component in each polymerization reaction vessel to 0.215mol, heat-melt mix under nitrogen atmosphere, and gradually increase the internal temperature.
The temperature was raised to 295 ° C and a high vacuum of 1 torr or less was simultaneously obtained. While maintaining this temperature and pressure, a polycondensation reaction was carried out for 60 minutes to obtain a polycondensate.

The above polycondensate was placed in a flask and the internal pressure was adjusted.
After heating at 160 ℃ for 10 hours while maintaining 0.2 to 0.5 Torr, 230 ℃
Was heated in an oil bath for 20 hours for solid phase polymerization. The intrinsic viscosity of the treated polyester copolymer was 0.92 dL / g and the melting point was 283 ° C.

A specimen obtained by injection molding at a nozzle temperature of 300 ° C. has a breaking elongation of 40% and a notched Izod impact strength of 3.
It was 8 kg · cm / cm ² .

Example 2 The polycondensate obtained in Example 1 was placed in a flask and heated at 160 ° C. for 10 hours while maintaining the internal pressure at 0.2 to 0.5 Torr, then 250
Solid-state polymerization was carried out by heating in an oil bath at ℃ for 13 hours. The intrinsic viscosity of the treated polyester copolymer was 1.10 dL / g and the melting point was 282 ° C.

A specimen obtained by injection molding at a nozzle temperature of 300 ° C. has a breaking elongation of 45% and a notched Izod impact strength of 4.
It was 0 kg · cm / cm ² .

Example 3 The polycondensate obtained in Example 1 was placed in a reaction tube, and the internal temperature was kept at 160 ° C. for 10 hours under a nitrogen stream of 10 ml per 1 g of polycondensate, and then kept at 250 ° C. Solid-state polymerization was carried out by heating for 13 hours. The intrinsic viscosity of the treated polyester copolymer is
The melting point was 0.93 dL / g and the melting point was 281 ° C.

A specimen obtained by injection molding at a nozzle temperature of 300 ° C. has a breaking elongation of 42% and a notched Izod impact strength of 3.
It was 8 kg · cm / cm ² .

Example 4 The transesterification product obtained in Preparation Example 1 was adjusted so that the content of 1,4-butanediol was 0.18 mol, and the transesterification product obtained in Preparation Example 2 was changed to 1,4-cyclohexanediene. Put each methanol component into the reaction vessel for polymerization so that it was 0.27 mol, heat melt under nitrogen atmosphere and mix, then gradually increase the internal temperature.
The temperature was raised to 305 ° C. and, simultaneously, a high vacuum of 1 Torr or less was set. While maintaining this temperature and pressure, a polycondensation reaction was carried out for 60 minutes to obtain a polycondensate. The obtained polycondensate was placed in a flask and heated at 160 ° C. for 10 hours while maintaining the internal pressure at 0.2 to 0.5 Torr, and then heated in an oil bath at 250 ° C. for 13 hours to carry out solid phase polymerization. The intrinsic viscosity of the treated polyester copolymer is 0.88
The dL / g and the melting point were 296 ° C.

The breaking elongation of the test piece obtained by injection molding at a nozzle temperature of 310 ° C. was 38%, and the notched Izod impact strength was 3.
It was 6 kg · cm / cm ² .

Comparative Example 1 194 parts of dimethyl terephthalate and 130 parts of ethylene glycol were placed in a reactor equipped with a rectification column, heated and melted at a bath temperature of 190 ° C., and then titanium tetranormal butoxide was added.
25 parts was added, and the reaction was carried out while raising the bath temperature to 240 ° C. When 64 parts of methanol and 8 parts of ethylene glycol were distilled, the reaction was stopped to obtain an ester exchange product composed of a terephthalic acid component and an ethylene glycol component. The obtained transesterification product was placed in a polymerization reaction vessel, heated and melted in a nitrogen atmosphere, and then the internal temperature was gradually raised to 290 ° C., and at the same time, a high vacuum of 1 Torr or less was set. The polycondensation reaction was carried out while maintaining this temperature and pressure. The obtained polycondensate was placed in a flask, heated at 160 ° C. for 10 hours while keeping the internal pressure at 0.2 to 0.5 Torr, and heated at 230 ° C. in an oil bath for 13 hours to carry out solid phase polymerization. The intrinsic viscosity of the treated polyester copolymer was 0.98 dL / g and the melting point was 269 ° C.

Comparative Example 2 194 parts of terephthalic acid dimethyl ester and 189 parts of 1,4-butanediol were placed in a reactor equipped with a rectification column, heated and melted at a bath temperature of 190 ° C., and then titanium tetranormal butoxide of 0.1 part was added.
24 parts was added, and the reaction was carried out while raising the bath temperature to 260 ° C. The reaction was stopped when 64 parts of methanol and 14 parts of 1,4-butanediol were distilled out to obtain an ester exchange product consisting of a terephthalic acid component and a 1,4-butanediol component. The obtained transesterification product was placed in a polymerization reaction vessel, heated and melted in a nitrogen atmosphere, and then the internal temperature was gradually raised to 260 ° C., and at the same time, a high vacuum of 1 Torr or less was set. While maintaining this temperature and pressure, a polycondensation reaction was carried out for 60 minutes. Put the obtained polycondensate in the flask, while maintaining the internal pressure at 0.2 ~ 0.5 Torr 130
After heating at ℃ for 10 hours, it was heated in an oil bath at 200 ℃ for 13 hours to carry out solid phase polymerization. The intrinsic viscosity of the treated polyester copolymer was 1.08 dL / g and the melting point was 238 ° C.

Comparative Example 3 The transesterification product obtained in Preparation Example 1 was mixed with 1,4-butanediol component in an amount of 0.215 mol, and the transesterification product obtained in Preparation Example 2 was converted into 1,4-cyclohexanediene. Put each methanol component in the polymerization reaction vessel to 0.215 mol, heat and melt mix under a nitrogen atmosphere, then gradually increase the internal temperature.
The temperature was raised to 295 ° C. and, simultaneously, a high vacuum of 1 Torr or less was set. While maintaining this temperature and pressure, a polycondensation reaction was carried out for 60 minutes.

The composition ratio of the glycol component of the obtained polycondensate was 1,4-butanediol / 1,4-cyclohexanedimethanol = 33/67, the intrinsic viscosity was 0.69 dL / g, and the melting point was 27.
It was 6 ° C.

A specimen obtained by injection molding at a nozzle temperature of 300 ° C. has a breaking elongation of 12% and a notched Izod impact strength of 2.
It was 9 kg · cm / cm ² .

[0032]

As is apparent from the above, according to the present invention, the following various advantages are achieved. -It is possible to obtain a resin having high heat resistance that cannot be realized with polyethylene terephthalate or polybutylene terephthalate; -Manufacturing a resin having a higher degree of polymerization than polyethylene cyclohexylene dimethylene naphthalate and suitable for injection molding.・ Polybutylene cyclohexylene dimethylene naphthalate having a large degree of polymerization can be obtained, so that the elongation at break of the molded product,
Improves mechanical properties such as Izod impact strength; ・ Because low molecular weight volatile by-products can be removed, when applied to electronic materials or food-related materials, residual low molecular weight components are extracted after molding and used for other purposes. No fear of damage;

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsuhiko Murao 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A glycol component is 1,4-butanediol.
When a polyester copolymer comprising two components of 1,4-cyclohexanedimethanol and an acid component of 2,6-naphthalenedicarboxylic acid was produced, first, solution polycondensation and / or melt polycondensation was performed to obtain a polyester copolymer. Process for producing polyester copolymer, characterized in that polycondensate is further solid-phase polymerized at a temperature below its melting point