KR100372184B1 - Method for preparing polyester copolymer having high transparency - Google Patents

Abstract

The present invention relates to a method for preparing an environmentally friendly polyester copolymer having excellent transparency, and more specifically, dimethyl terephthalate, ethylene glycol and 1,4-cyclohexanedimethanol are mixed at a weight ratio of 1: 0.6: 0.2. At the same time, a composite catalyst consisting of antimony trioxide, tetraisopropyl di (dioctyl) phosphite titanate, neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl titanate and cobalt acetate was added to the final polyester copolymer. It relates to a method of producing an environmentally friendly polyester copolymer having excellent transparency comprising the step of mixing the ester to 100 to 3,000ppm to produce an ester of a low polymer and the polycondensation of the ester. In the present invention, it is possible to manufacture an environmentally friendly polyester copolymer having improved thermal stability and transparency, as well as a significant increase in industrial production through the development of a composite catalyst, as compared to conventional P.E.T.-based polyester copolymers.

Description

Method for preparing environmentally friendly polyester copolymer having high transparency {Method for preparing polyester copolymer having high transparency}

The present invention relates to a method for producing an environmentally friendly polyester copolymer having excellent transparency, and more specifically, in preparing a polyethylene terephthalate (PET) -based polyester copolymer to which an aliphatic or alicyclic compound is added, an antimony compound And a method for producing a polyester copolymer having excellent transparency, which is environmentally friendly, by improving the transparency and thermal stability in terms of physical properties and replacing environmental pollutants with these materials in terms of physical properties using a composite catalyst composed of titanium / phosphorus compounds. will be.

In general, the heat shrink tube that shrinks due to heat is obtained by a processing method of stretching at a high temperature higher than the melting temperature of the tube resin itself and rapidly cooling to maintain the stretched state. Conventional representative heat shrink tubes were mainly polyvinyl chloride (P.V.C.), and these P.V.C. Resins have been widely used in the fields of wire and cable connection coatings, terminal wires for mechanical wires, metal pipe welding parts, and insulation coatings for corrosion protection of pipes, capacitors, batteries, and food packaging. In particular, aluminum electrolytic capacitors used for electrical insulation, etc., had a conventional maximum operating temperature of 85 ° C, but now the performance of the product has been improved, and the operating temperature has increased to 105-130 ° C. It's happening.

P.V.C. conventionally used for this purpose. In terms of physical properties, resins have a maximum service temperature of 105 ℃, and cracks in the shrinkage tube may cause problems in durability, and decompose during heat shrinkage, degrading electrical and mechanical properties and having a high risk of fire. . In addition, P.V.C. If the resin is continuously heated from the environmental point of view, exports and imports between countries are regulated under the Green Round Agreement because the chlorine component included in the hazardous chemical substance becomes a gas, which causes fatal damage to the surrounding environment to which the resin is applied. Are restricted to regulated substances.

Therefore, there is a need for a new polyester-based heat shrink tube that is resistant to heat when using the heat shrink tube for a long time at a high temperature according to the improvement of reliability and performance of electronic components and the difficulty of export due to environmental regulations.

In such a situation, it was intended to solve this problem by using a polyester which is currently widely used as an environment-friendly resin. Among them, polyethylene terephthalate (PET) resin has a high melting temperature and is widely used in textiles, films and other industrial materials because of its excellent properties in strength, chemical resistance, heat resistance, weather resistance and electrical insulation. It is also suitable for use as a heat shrink tube. However, P.E.T. Since extrusion molding is difficult with resin alone, a third compound, for example, an aliphatic or alicyclic compound, is added alone or at the same time to facilitate extrusion molding, and then a heat shrinkable tube is manufactured. US Magazine of Polymer Engineering and Science, Vol. 28, pp. 1260-1263 (1988); US Pat. No. 5,395,987; and EP 994909).

However, these P.E.T.-based polyester copolymers contain a large amount of the third compound in order to facilitate the extrusion process. The catalyst method and the production method used in the polymer have introduced a new complex catalyst because of poor thermal stability and transparency.

Generally P.E.T. In the first step, the dimethyl terephthalate (or terephthalic acid) and ethylene glycol are heated to a reaction temperature of 200 to 250 ° C. under normal pressure (or pressurization). Roxyethyl) terephthalate and its oligomer were obtained, and then the reaction temperature was raised to 260 to 290 ° C, followed by polycondensation reaction under high pressure reduction to PET. Resin is manufactured. However, these P.E.T. Since the production of the resin is carried out for a long time at a high temperature under a metal catalyst, various undesirable side reactions are involved, resulting in the resulting polymer being colored or opaque in yellow and deteriorating thermal stability. Therefore, a method of preparing a transparent and excellent thermal stability polyester even at a high reaction rate is very important. At present, the most commonly used polycondensation catalysts are antimony compounds, in particular antimony trioxide, because they are appropriate in price and relatively excellent in catalytic activity. However, when antimony trioxide is used alone, it is difficult to dissolve with ethylene glycol and has a problem of poor transparency of the finally obtained polyester polymer.

Conventionally, methods for shortening the reaction time or manufacturing polyester having excellent color and thermal stability have been proposed, but it is difficult to find satisfactory. For example, antimony / cobalt / alkali metal compounds are used (JP-A-83-177,216), antimony / cobalt / phosphorus compounds are used (JP-A-78-51,295), and antimony / tin compounds are used ( Japanese Patent Application Laid-Open No. 74-31,317), titanium / copper compound (US Patent No. 4,929,777), antimony / tin / cobalt / alkali metal / phosphorus compound (Japanese Patent Publication No. 87-265,324), etc. Although this is known, even with these methods, the color, transparency and thermal stability of the PET copolymer are not improved at the same time and there is no great advantage in terms of shortening the reaction time.

Accordingly, the present inventors have studied steadily to prepare a polyester copolymer having improved thermal stability and transparency and being environmentally friendly, and thus have completed the present invention.

Accordingly, it is an object of the present invention to provide a method for producing an environmentally friendly polyester copolymer having excellent transparency and thermal stability.

Method for producing a polyester of the present invention for achieving the above object is a mixture of dimethyl terephthalate, ethylene glycol and 1,4-cyclohexane dimethanol in a weight ratio of 1: 0.6: 0.2, at the same time antimony trioxide, tetraisopropyl di A mixed catalyst consisting of (dioctyl) phosphite titanate, neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl titanate and cobalt acetate was mixed at 100 to 3,000 ppm with respect to the final polyester copolymer. Reacting to produce an esterified oligomer; And polycondensation the esterified product.

Looking at the present invention in more detail as follows.

In the present invention, when dimethyl terephthalate, ethylene glycol and / or 1,4-cyclohexanedimethanol are esterified to obtain an ester of a low polymer, it is subsequently polycondensed to prepare a PET-based polyester copolymer. It is characterized by using a complex catalyst in which an antimony compound and a titanium / phosphorus compound are dissolved in ethylene glycol as a reaction catalyst.

The amount of the catalyst used in the present invention is preferably 100 to 3,000 ppm, more preferably 400 to 1,000 ppm, based on the total amount of the antimony compound and the titanium / phosphorus compound relative to the finally obtained polyester copolymer. In addition, the addition time may be added before or after the ester reaction, but most preferably, it is added before the ester reaction.

The mixing ratio of the antimony compound and the titanium / phosphorus compound is preferably 1: 0.5 to 5.0 by weight, and if less than 0.5, the color of the final polymer tends to be green, and if it exceeds 5.0, the color of the final polymer is yellow. Banding tends to In addition, when preparing a complex catalyst solution consisting of antimony compound and titanium / phosphorus compound, the heating temperature is preferably 20 ℃ to 200 ℃, more preferably 100 to 150 ℃. At this time, when the heating temperature exceeds 200 ° C., the titanium / phosphorus compound tends to be carbonized.

The antimony compounds used for the complex catalyst include antimony trioxide, antimony tetraoxide, antimony oxide such as antimony pentoxide, antimony halide such as antimony trichloride, and antimony carboxylate such as antimony triacetate, but preferably antimony trioxide. .

In addition, a typical titanium / phosphorus compound used for the complex catalyst is a titanium / phosphorus compound having an ether bond represented by Ti (OR) ₄ . R in Ti (OR) ₄ is the same as or different from each other an aliphatic or alicyclic alkyl group having 2 to 18 carbon atoms, or an aromatic aryl group, and at least one of the four (OR) s is substituted with HP (O) (OR '), wherein R' is the same as or different from each other, an aliphatic or alicyclic alkyl group having 2 to 18 carbon atoms, or an aromatic aryl group, and is the same as or different from R.

Examples of the titanium / phosphorus compound include tetra (2,2-diallyloxymethyl) butyl di (ditridecyl) phosphito titanate, tetranormalbutyl di (diisopropyl) phosphito titanate, tetraisopropyl di ( Dimethyl) phosphito titanate, tetraisopropyl di (dioctyl) phosphito titanate, and the like.

Titanium compounds that can additionally be used with the titanium / phosphorus compounds are, for example, monoalkoxy titanate compounds such as isopropyl triisostearoyl titanate, chelate titanate compounds such as dicumylphenyloxoethylene titanate Neoalkoxy titanate compounds such as neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl titanate, or cycloheteroatomitanate compounds such as cyclo (dioctyl) pyrophosphate dioctyl titanate This is possible.

In addition, you may use the 1 type (s) or 2 or more types of several antimony compounds and titanium / phosphorus type compound mentioned above together, respectively.

The activity of the catalysts used in the present invention is good at 200 to 240 ° C. for the transesterification reaction, and 220 to 260 ° C. for the direct esterification reaction, and the polycondensation reaction temperature is 260 to 300 ° C., particularly preferably 280 to 290 degreeC. In addition, the catalytic activity works well in either the normal pressure or the pressurization method, and the final vacuum degree in the polycondensation reaction is less than 1 Torr to give good results. In addition, other reaction catalysts or additives may be used without departing from the object of the present invention. For example, there are complementary agents such as cobalt acetate, antifoaming agents, quenchers, nucleating agents, antistatic agents and flame retardants.

The present invention is effectively applied when a PET-based polyester copolymer is prepared by reacting dimethyl terephthalate and its derivatives, aliphatic glycols and alicyclic glycols containing ethylene glycol and / or 1,4-cyclohexanedimethanol as main components. . At this time, the reaction ratio of dimethyl terephthalate and its derivatives and ethylene glycol is preferably 1: 0.5 by weight, and the reaction ratio of dimethyl terephthalate and its derivatives, ethylene glycol and 1,4-cyclohexanedimethanol is weight ratio (or molar ratio). Is preferably 1: 0.6: 0.2. In addition, the polyester copolymer may be prepared by further adding at least one third component in addition to the above components.

In the present invention, the third component is phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenylmethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, malonic acid and succinic acid. , Dicarboxylic acid, glutaric acid, adipic acid, azelinic acid, sebacic acid, cyclohexanedicarboxylic acid, decalinic dicarboxylic acid and the like, 1,3-propanediol, 1,2-propanediol, 1,4 Glycol components such as butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, bisphenol A, and trimellitic acid, trimesic acid and pyromellitic acid , Polyfunctional crosslinking agent compounds such as trimethyrolpropane, glycerin and the like.

Meanwhile, a phosphorus compound is generally used as a heat stabilizer commonly added in the manufacture of polyester. In the present invention, a phosphorus compound is included in the titanium / phosphorus compound so that thermal stability may be imparted to the polyester copolymer without addition thereof. have. However, a phosphorus compound can be added as needed. Examples of phosphorus compounds usable in the present invention include phosphoric acid, metaphosphoric acid, trimethylphosphate, triethylphosphate, triphenylphosphate, trioctylphosphate, dimethylpyrophosphate, diethylphosphate, diethylpyrophosphate, diphenylpyrophosphate, dicyclo Phosphoric acid series such as hexyl pyrophosphate, dioctyl pyrophosphate and the like and phosphorous acid series such as phosphorous acid, dimethyl phosphite, diethyl phosphite, dicyclohexyl phosphite, diphenyl phosphite, dioctyl phosphite, and the like can be used.

As such, in the present invention, not only can the industrial production be significantly increased by using the composite catalyst which improves the reaction rate than the existing catalyst, but also a polyester copolymer having improved transparency and thermal stability can be prepared. In particular, by increasing the viscosity of the composite catalyst, mechanical properties and the like are improved to have a sufficient property for practical use, it is possible to provide a high-quality polyester having excellent thermal stability and excellent color and transparency compared to the conventional method.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example 1

194.19 g of dimethyl terephthalate, 46.88 g of 1,4-cyclohexanedimethanol and 630 ppm of a combined catalyst were charged into the reactor. The composition of 630ppm of the complex catalyst was 300ppm of antimony trioxide, 150ppm of tetraisopropyldi (dioctyl) phosphite titanate, 150ppm of neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl titanate, and 30ppm of cobalt acetate. First, 194.19 g of ethylene glycol was mixed, and then prepared by heating at about 70 ° C. for about 90 minutes. The reaction temperature is 230 ℃, transesterified at atmospheric pressure to terminate the reaction at residence time 3 hours, the esterified product is transferred to a polycondensation reactor, gradually raised the temperature to a final temperature of about 285 ℃ and gradually reduced the pressure The final pressure was set at 1.0 Torr or less. The reaction was terminated at 2 hours of polycondensation reaction time and extruded into cooling water through the lower nozzle of the reactor to obtain a P.E.T.-based copolymer in a chip state. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. Detailed results for this are shown in Table 1 below.

Example 2

194.19 g of dimethyl terephthalate, 130.35 g of ethylene glycol, and 630 ppm of a combined catalyst (300 ppm of antimony trioxide and tetraisopropyldi (dioctyl) phosphite titanate 150 ppm, neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl Titanate 150ppm, cobalt acetate 30ppm) was put into the reactor and reacted for 3 hours while removing the water produced at 230 ℃ by removing the system out of the PET Oligomer was obtained. The resulting oligomer was placed in a reactor and reacted at 285 ° C. under 1.0 Torr under reduced pressure for 2 hours to complete the polycondensation reaction. A polymer was obtained. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. The results are shown in Table 1 below.

Comparative Example 1

194.19 g of dimethyl terephthalate, 130.35 g of ethylene glycol, and 600 ppm of zinc acetate were added to a reactor, and the produced water was reacted for about 3 hours while flowing out of the system at 230 ° C. to remove P. T. oligomer. 300 ppm of antimony trioxide and 100 ppm of trimethyl phosphate were put into a reactor, and the resulting oligomer was reacted at 285 ° C. under a reduced pressure of 0.2 Torr for 2 hours to complete the polycondensation reaction to obtain a P. E. polymer. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. The results are shown in Table 1 below.

Comparative Examples 2 to 3

In Example 1, 109.38 g of ethylene glycol was added with only 150 ppm of tetraisopropyldi (dioctyl) phosphite titanate and 150 ppm of neopentyl (diallyl) oxytri (N-ethylenediamino) ethyl titanate. Only 300 ppm of antimony trioxide was added to ethylene glycol, and the reaction was carried out in Comparative Example 4. 46.88 g of cyclohexanedimethanol was added thereto, 194.19 g of dimethyl terephthalate was added thereto, and the reaction was carried out under the same conditions as in Example 1 to finally obtain a P.E.T.-based copolymer. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. The results are shown in Table 1 below.

Example 3

Only the composite catalyst composition (300 ppm of antimony trioxide and 300 ppm of tetraoctyldi (ditridecyl) phosphito titanate) was different for the polyester copolymer having the same reactant composition as in Example 1. The remaining reaction raw materials, ester reaction and polycondensation reaction conditions were reacted under the same conditions as in Example 1 to finally obtain a P.E.T.-based copolymer. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. The results are shown in Table 1 below.

Comparative Example 4

Only the composite catalyst composition (300 ppm antimony trioxide and 300 ppm tetrabutyl titanate) was changed for the polyester copolymer having the same reactant composition as in Example 1. The remaining reaction raw materials, ester reaction and polycondensation reaction conditions were the same as in Example 1, and 100 ppm of trimethyl phosphate as a heat stabilizer was added to the polycondensation reaction to finally obtain a P.E.T.-based copolymer. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined. The results are shown in Table 1 below.

Example 4

Complex catalyst (600 ppm antimony trioxide, tetraisopropyldi (dioctyl) phosphito titanate 300ppm, neopentyl (diallyl) oxytri (N-ethylenediamino) under the same conditions of ester reaction and polycondensation reaction as in Example 1 ) Only 300 ppm of ethyl titanate and 60 ppm of cobalt acetate were doubled to 1260 ppm. The remaining reaction raw materials, ester reaction and polycondensation reaction conditions were reacted under the same conditions as in Example 1 to finally obtain a P.E.T.-based copolymer. The polymer thus obtained was filmed by press molding at a temperature of about 40 ° C. above the melting point, and the overall properties were examined.

In Table 1 below, 0.25 g of the sample obtained in Examples and Comparative Examples was dissolved in 25 ml of a mixed solvent (25 parts of phenol: 35 parts of 1,1,2,2-tetrachloroethane: 40 parts of parachlorophenol) and 25 Intrinsic viscosity (η _int ) was calculated with a Ubelrod viscometer at ° C. In addition, the sample was dissolved in benzyl alcohol and the acid terminal was measured by neutralization titration. Also, the color of the polymer was measured in a film state using a color difference meter. Usually, the larger the L value, the smaller the b value, the better the color. The maximum melting point (T m ) was examined with a differential scanning calorimeter.

Exam number Intrinsic viscosity Mountain terminal concentration [COOH] brightness ecliptic Melting point (Tm) (㎗ / g) Equivalent / tons L b ℃ Example 1 0.60 23 80 1.2 250 Example 2 0.64 24 77 1.5 255 Comparative Example 1 0.63 26 67 1.9 254 Comparative Example 2 0.56 35 51 2.7 247 Comparative Example 3 0.45 47 40 4.6 240 Example 3 0.59 26 75 1.8 249 Comparative Example 4 0.57 27 73 1.9 248 Example 4 0.60 26 79 1.7 249

As described above, the present invention provides a method for producing an environmentally friendly polyester copolymer having excellent thermal stability and transparency. That is, the present invention provides a PET-based polyester copolymer composed of dimethyl terephthalate, ethylene glycol and / or 1,4-cyclohexanedimethanol, which is a starting material of polyethylene terephthalate, an antimony compound, and a titanium / phosphorus compound. Conventional PET using a complex catalyst It is to produce an environmentally friendly polyester copolymer having improved viscosity, thermal stability and excellent transparency at the polymer level.

As such, through the development of a composite catalyst that improves the reaction rate than the conventional catalyst, not only the industrial production is greatly increased, but also the polyester copolymer having improved transparency is prepared. In particular, by increasing the viscosity of the composition, it is possible to provide a polyester composition having a property sufficient to improve the mechanical properties and the like to practical use.

Claims (10)

Dimethyl terephthalate, ethylene glycol and 1,4-cyclohexanedimethanol are mixed at a weight ratio of 1: 0.6: 0.2, and simultaneously antimony trioxide, tetraisopropyl di (dioctyl) phosphito titanate, neopentyl (diallyl) Mixing a mixed catalyst consisting of oxytri (N-ethylenediamino) ethyl titanate and cobalt acetate at 100 to 3,000 ppm with respect to the final polyester copolymer to produce an esterified oligomer; And Polycondensing the esterified product; Method for producing an environmentally friendly polyester copolymer having excellent transparency, characterized in that it comprises a. delete delete The mixing ratio of the antimony trioxide and tetraisopropyl di (dioctyl) phosphite titanate is 1: 0.5 to 5.0 by weight, and the neopentyl (diallyl) oxytri (N-ethylenediamino) The content of ethyl titanate is 150 to 300 ppm relative to the final polyester copolymer, and the content of cobalt acetate is 30 to 60 ppm relative to the final polyester copolymer. Way. The method of claim 1, wherein the composite catalyst is dissolved in ethylene glycol in a temperature range of 20 ° C to 200 ° C. delete delete delete delete The method according to claim 1, wherein the reaction temperature of the ester reaction is 200 to 260 ° C and the temperature of the polycondensation reaction is 260 to 300 ° C.