KR0145752B1 - Process for preparing polyether esther copolymer - Google Patents

Abstract

The present invention provides thermal stability, melt strength and melt viscosity by adding a thioether compound having a polyfunctional group as a crosslinking agent during the preparation of a polyether ester copolymer using low molecular weight glycol, bifunctional carbolic acid and polyalkylene glycol. Relates to a process for producing high polyether ester copolymers.

Description

Method for preparing polyether ester copolymer

The present invention relates to a method for producing a high viscosity polyether ester copolymer having excellent thermal stability. More specifically, the present invention provides thermal stability and melting by adding a thioether compound having a polyfunctional group as a crosslinking agent during the preparation of a polyether ester copolymer using low-division glycol, difunctional carboxylic acid and polyalkylene glycol. A method for producing a polyether ester copolymer having high strength and melt viscosity.

Polyether ester copolymer prepared in the present invention is excellent in moldability, heat resistance, oil resistance, low temperature characteristics and mechanical properties, by using the high elasticity of the hose, tube, wire, automobile parts, electrical by extrusion or air molding It is used for various purposes such as manufacturing electronic parts, sheets, films, and highly stretchable fibers.

In general, the polyether ester copolymer is a non-crystalline long-chain soft segment of the polyether component exhibiting elasticity, the crystallinity is destroyed when subjected to a few heat, but recovers the crystallinity again when the heat is removed. It consists of crystalline short chain hard segments. Since the polyether ester copolymer has an intermediate property of rubber and plastic properties according to the composition ratio of the soft segment and the hard segment, the amount of the soft segment and the hard segment is arbitrarily adjusted depending on the purpose of use during its polymerization. Can be used to the maximum.

Although polyether ester copolymers are mainly produced by melt polymerization, polymerization is often performed at a relatively low temperature to prevent decomposition of polyalkylene glycols, and the melt viscosity of the resulting polymer is sufficient for injection molding, but extrusion molding And insufficient blow molding. On the other hand, if the solid phase polymerization method is used to increase the melt viscosity to enable extrusion molding and blow molding, it is inferior in economic efficiency because it requires a long time reaction to obtain a sufficient viscosity.

Japanese Patent Laid-Open Nos. 48-100495 and US Pat. No. 3553157 disclose a method of increasing the melt viscosity of a polyether ester copolymer by blending an epoxy compound. However, polyepoxy compounds easily increase the melt viscosity of the copolymer, but compounds with epoxy groups composed of only carbon, hydrogen, oxygen, and halogens have high viscosity when the polyether ester copolymer has low reactivity with terminal groups and does not use catalysts such as amines. It is not possible to obtain a polyether ester copolymer having a high melt viscosity by using a catalyst, which has a disadvantage in that heat resistance is poor.

Japanese Patent Laid-Open No. 51-143055 discloses a method of blending an ionomer in a polyether ester copolymer. When blending the ionomer, the melt viscosity of the polyether ester copolymer increases, but the compatibility between the ionomer and the polyether ester copolymer is poor, so the amount of the ionomer used is 10 to 15% by weight based on the weight of the copolymer. Since it is limited, sufficient melt viscosity cannot be obtained and there is a disadvantage in that the transparency of the molded fish product is poor.

Japanese Patent Laid-Open No. 52-4549 discloses a method of mixing a monocarboxylic acid sodium salt with a polyether ester copolymer. When the sodium salt is mixed, the transparency becomes good, but the synergistic effect of the melt viscosity is insufficient.

In addition, in US Patent No. 4013624, as a crosslinking agent, 0.3 to 1.2 molding% of a polyfunctional compound consisting of only a hydroxy group and a carboxyl group was added to dicarboxylic acid to induce chemical crosslinking. There was a disadvantage in that the thermal stability was lowered due to an increase in the short-term content.

Accordingly, the present inventors earnestly studied to prepare a high viscosity polyether ester copolymer having excellent thermal stability, and therefore, the present inventors reacted with ester-forming functional groups during esterification or transesterification or polycondensation reactions. By adding a multifunctional thioether compound having a functional group capable of inducing a small amount of chemical crosslinking in the polyether ester copolymer, the final polymer was found to improve not only thermal stability but also melt viscosity and melt strength. The present invention has been completed as a result of a suitable combination of the type, amount and timing of addition of the er-based compound, the catalyst and the stabilizer.

It is an object of the present invention to provide a method for producing a polyether ester copolymer having high thermal stability, melt strength and melt viscosity.

Hereinafter, the present invention will be described in more detail.

The present invention provides a polyether ester copolymer by polycondensing a product obtained by esterification or transesterification of a low molecular weight glycol, a bifunctional kyric acid and a polyalkylene glycol, wherein (a) a low molecular weight glycol, The bifunctional is esterified or transesterified by adding a catalyst and a stabilizer to the reactants of carboxylic acid and polyalgiene glycol, and when the reaction proceeds more than 90%, the stabilizer is added again to complete the reaction (b) The product is transferred to a polycondensation reactor and the polycondensation reaction is carried out in a high vacuum state by re-adding the starter, and the thioether compound having a multifunctional group is subjected to the esterification reaction or the ether exchange reaction of step (a) or step (b). The present invention relates to a method for producing a polyether ester copolymer, which is added at the time of a polycondensation reaction.

As the difunctional carboxylic acid of the present invention, for example, terephthalic acid or dimethyl terephthalate can be used, and as other copolymerization components, isophthalic acid, dimethyl isophthalate, adipic acid, suberic acid, sebacic acid, 1, 5-naphthalene dicarboxylic acid, 2, 6-niphthalene dicarboxylic acid, dimethyl 2, 6-naphthalate or 1, 4-cyclohexane dicarboxylic acid, etc. may be used in less than about 20 mol% of the total acid component. Can be.

Examples of low molecular weight glycols include 1,4-butanediol and other copolymerization components such as ethylene glycol 1, 3-propanediol, 1, 5-pentanediol, 1,6-hexanediol, or 1,4-cyclohexanedimethanol. It can be used in about 20 mol% or less of the whole low molecular weight glycol component.

Examples of the polyalkylene glycol used in the present invention include polyethylene glycol, polypropylene glycol or polytetramethylene glycol, and these may be used alone or in combination. Depending on the type of polyalkylene glycol used, the physical properties of the final polymer are affected. Polyethylene glycol is more hydrophilic than polypropylene glycol and polytetramethylene glycol, so that the water resistance of the polymer is lowered, but oil resistance is advantageous, and polypropylene glycol and polydetramethylene glycol are hydrophobic, and thus the polymer And hydrolyzable.

Since the polyalkylene glycol is hydrophobic, the polymer has excellent water resistance and hydrolysis resistance.

The polyalkylene glycol is preferably used in the range of 20 to 80% by weight of the polyether ester copolymer. The higher the amount of polyalkylene glycol used, the closer the physical properties to rubber than plastic. At 20% by weight or less, the elasticity and elastic recovery rate of the polyether ester copolymer decreases, and at 80% by weight or more, the mechanical properties after the high temperature heat treatment are poor and the moldability is poor. The average molecular weight of the polyalkylene glycols used is preferably in the range of 500 to 4000. If polyalkylene glycol having an average molecular weight of 500 or less is used, the mechanical properties after the high temperature heat treatment may be lowered and may not be reacted during the reaction under high temperature and high vacuum. If polyalkylene glycol having an average molecular weight of 4000 or more is used, mechanical properties decrease and it is difficult to obtain a high molecular weight polymer.

An example of a thioether compound having a multifunctional group used in the present invention is pentaerythritol tetrakis (beta-dodecylthiopropionate). The thioether compound is preferably used in the range of 0.04 mol% to 1.0 mol% with respect to the bifunctional carboxylic acid, and is added during the esterification reaction or the transesterification reaction or the polycondensation reaction. When the amount of the compound used is 0.04 mol% or less, desired thermal stability and melt strength cannot be obtained, and the range of 1.0 mol% or more is not preferable because the density of crosslinking crosslinking in the polymer is high, resulting in poor workability and deterioration of physical properties.

Examples of the catalyst used in the present invention include tetra alkyl titanates such as tetra isopropyl titanate, tetra butyl titanate, tetra ethyl titanate and tetra methyl titanate. They are used alone or as a mixture of magnesium, lithium or calcium acetate, and the amount of use is preferably in the range of 0.01 to 0.6% by weight relative to the difunctional carboxylic acid. When the amount of the catalyst used is 0.01% by weight or less, the esterification reaction or the transesterification reaction is insufficient, and the polycondensation reaction does not proceed sufficiently to obtain a polymer having a sufficient degree of polymerization. If it is more than 0,6% by weight, the reaction rate is not a problem, but the fished polymer is not good in color. The catalyst is added during the esterification or transesterification reaction and further added during the polycondensation reaction.

As the stabilizer used in the present invention, an amide compound can be used, and Irganox 1098 (product of Ciba-Geigy Co.) is particularly preferable. Its use amount is preferably in the range of 0.05 to 2% by weight based on the difunctional carboxylic acid. If it is 0.05 wt% or less, the effect as a stabilizer is insufficient, and if it is 2 wt% or more, the color of a polymer worsens and mechanical properties fall. The stabilizer is added at the beginning of the esterification or transesterification reaction and additionally at the time when the esterification or transesterification reaction is at least 90% or at the beginning of the polycondensation reaction.

In the method of the present invention, in addition to the above-mentioned components, ultraviolet absorbers, pigments, or optical brighteners generally used in the preparation of the polyether ester copolymer may be used.

Hereinafter, the present invention will be described in more detail as examples. The following examples merely illustrate the invention and are not intended to limit the invention thereto.

The physical properties of the polymers prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were measured using the following test conditions and methods, and the results are shown in Table 1.

1) Melt index: measured at 190 ° C and a load of 2160g by ASTM D-1238.

2) Melting Point: Measured by differential thermal analyzer (DSC).

3) Tensile strength: measured by ASTM D-638.

4) Heat resistance: Tensile strength retention rate is measured after 4 days in 150 ℃ hot air dryer. The higher the retention, the better the heat resistance.

Example 1

970 g of dimethyl terephthalate, 567 g of 1,4-butanediol and 1200 g of polytetramethylene glycol (average molecular weight 1000) were placed in a reactor, 6.97 g of pentaerythritol tetrakis (beta-dodecylthiopropionate), 0.49 g of tetrabutyl titanate, and After the addition of 1.94 g of Irganox 1098 (IRGANOX 1098 (Shibagaiki Co., Ltd.)), a transesterification reaction was carried out at a normal pressure while gradually increasing the temperature from 140 ° C to 00 ° C. At a point where 90% of the theoretical amount of the methanol flowed out, 3.88 g of Irganox 1098 was added as a stabilizer, and after completion of the transesterification reaction, the product was transferred to the condensation reactor. 2.91 g of tetrabutyl titanate was added and the pressure was slowly maintained under a vacuum of 0.1 Torr under reduced pressure, and the reaction proceeded at 250 ° C. for 150 minutes.

Thereafter, nitrogen was injected to release the vacuum, and the polymer was discharged and cooled to obtain a final product, and dried under reduced pressure. The physical properties of the final product were measured and shown in Table 1 below.

Example 2

Example 1 and 1 except that the addition time of pentaerythritol tetrakis (beta-dodecylthiopropionate) was added at the time when 90% of the theoretical amount of the methanol flowed out during the transesterification reaction instead of the initial transesterification reaction. The polymer was prepared in the same manner and the physical properties of the final product are shown in Table 1.

Example 3

The polymer was prepared in the same manner as in Example 1, except that 931.2 g of dimethyl terephthalate and 38.8 g of dimethyl isophthalate were used instead of 970 g of dimethyl terephthalate. The physical properties of the final product are shown in Table 1.

Example 4

The polymer was prepared in the same manner as in Example 1 except that polytetramethylene glycol (average molecular weight 2000) was used instead of polytetramethylene glycol (average molecular weight 1000). The physical properties of the final product are shown in Table 1.

Example 5

The polymer was prepared in the same manner as in Example 1, except that 538.65 g of 1,4-butanediol and 19.53 g of ethylene glycol were used instead of 567 g of 1,4-butanediol. The physical properties of the final product are shown in Table 1.

Comparative Example 1

A polymer was prepared in the same manner as in Example 1 except that pentaerythritol tetrakis (beta-dodecylthiopropionate) was not used, and the physical properties of the final product are shown in Table 1.

Comparative Example 2

A polymer was prepared in the same manner as in Example 1, except that 0.82 g of pentaerythritol was used instead of 6.97 g of pentaerythritol tetrakis (beta-dodecylthiopropionate), and the physical properties of the final product are shown in Table 1.

Comparative Example 3

A polymer was prepared in the same manner as in Example 1, except that 1.15 g of trimellitic anhydride was used instead of 6.97 g of pentaerythritol tetrakis (beta-dodecylthiopropionate), and the physical properties of the final product are shown in Table 1. .

Claims (8)

In preparing a polyether ester copolymer by subjecting a product obtained by esterification or transesterification of low molecular weight glycol, difunctional carboxylic acid and polyalkylene glycol to (a) low molecular weight glycol, self-soluble caro A catalyst and an amide-based safety agent are added to the reaction product of the acid and the polyalkylene glycol, followed by esterification reaction or transesterification reaction, and when the reaction proceeds more than 90%, the safety agent is added again to complete the reaction, and then (b ) The product is transferred to a polycondensation reactor and the catalyst is re-added to polycondensation in a high vacuum state, wherein the bifunctional carboxylic acid is 0.04 to 1.0 mol% of pentaerythritol tetrakis (beta-dodecylthiopropionate). (a) during the esterification or transesterification reaction, or (b) during the condensation reaction. Process for producing a polyether ester copolymer as when. The method of claim 1, wherein the low molecular weight glycol is used alone or 4-butanediol or 20 mol% or less of ethylene glycol, 1, 3-propanediol, 1, 5-pentanediol, 1, 6-hexanediol or Method for use with 1, 4-cyclohexanedimethanol. The bifunctional carboxylic acid according to claim 1, wherein terephthalic acid or dimethyl terephthalate is used alone or 20 mol% or less of isophthalic acid, dimethylisophthalate, adipic acid, suberic acid, sebacic acid, 1, 5- Process with naphthalate or 1, 4-cyclohexane dicarboxylic acid. The method according to claim 1, wherein the polyalkylene glycol is polyethylene glycol, polypropylene glycol, polytetramethylene glycol or a mixture thereof having an average molecular weight of 500 to 4000. The method according to claim 1 or 4, wherein the amount of the polyalkylene glycol is 20 to 80% by weight based on the total weight of the polyetherester copolymer. The method according to claim 1, wherein the amount of the amide stabilizer is 0.05 to 2% by weight of the bifunctional carboxylic acid component. The method of claim 1 wherein the catalyst is a mixture of tetraalkyl titanate or tetraalkyl titanate with magnesium, lithium or calcium acetate. 8. The process according to claim 7, wherein the amount of the catalyst used is 0.01 to 0.6% by weight of the bifunctional carboxylic acid component.