WO2011037361A8

WO2011037361A8 - Polyester composition and a production method therefor

Info

Publication number: WO2011037361A8
Application number: PCT/KR2010/006347
Authority: WO
Inventors: 김남일; 김상묵; 최연주
Original assignee: 에스케이씨 주식회사
Priority date: 2009-09-24
Filing date: 2010-09-16
Publication date: 2011-06-03
Also published as: WO2011037361A3; KR101127951B1; KR20110032807A; WO2011037361A2

Abstract

A polyester composition, which comprises a polymer obtained by the polycondensation of an aliphatic dihydric alcohol, an aromatic diacid and a trivalent or higher polyfunctional compound by means of an antimony-based catalyst, has outstanding colour tone and transparency and can improve light transmittance when used in container moulding or in display optical film production.

Description

Polyester composition and its manufacturing method FIELD OF THE INVENTION The present invention relates to a polyester composition which can be used in fields such as a film for forming a container, a film for display optics, and a method for producing the same. Background Art [0002] Polyethylene terephthalate (PET), which is a representative polyester, has excellent transparency, heat resistance, mechanical properties, chemical resistance, etc., and is excellent in workability. In particular, biaxially stretched PET film has been used for several years since optical properties such as liquid crystal display (LCD), plasma display (PDP), projection display, and LCD protective film and release film used in manufacturing optical products. come.

In the case of PET film used in the optical field, since color tone and transparency are required, many efforts have been made to improve these characteristics. In terms of hue, brightness is important. As measured by color meter, the higher the L value indicating whiteness and the lower b value indicating yellowness, the better the brightness can be.

The color of polyester is largely affected by the metal compound used as polymerization catalyst. For example, the antimony (Sb) -based catalyst is used in the form of antimony trioxide or antimony acetate, and since antimony is reduced to form antimony metal particles, the color of polyester is darkened and light transmittance is reduced. have. In addition, the germanium (Ge) -based catalyst is excellent Although it may have color tone and transparency, the cost of the catalyst due to the revolving metal is high, and the cost of producing the polyester polymer is greatly increased, and the improvement of the brightness when the optical film is actually produced is not sufficient. There is a problem. In addition, in the case of an aluminum (A1) catalyst, Japanese Patent Laid-Open Publication No. 2006-096789, etc., claims that a polyester polymer having excellent color and transparency can be obtained. However, this method is also difficult to manufacture a catalyst and has a high cost. There is this.

In the case of titanium (TO-based catalyst, the color tone L of the polymer is excellent, but due to excessively high activity, thermal decomposition is severe at the end of the polymerization. As a result, the color tone b becomes high, and thus the luminance decreases when used in the manufacture of an optical film. In order to control the excessive reaction activity of such a titanium catalyst, Unexamined-Japanese-Patent No. 2006-160989, 2008-231281, 2006-003687, 2008-174582, 2008-056874, 2008-024756 et al. Disclose that a polyester polymer having excellent color and transparency can be obtained by appropriately adjusting the activity of a titanium catalyst using a phosphorus (P) compound or other metal compound. In order to prepare the catalyst separately, not only new equipment and processes are required, but also improvement of precipitation of oligomer, which is a disadvantage of the titanium catalyst, This is necessary.

On the other hand, since polyester is semicrystalline, transparency is generally lowered as it is crystallized. In order to prevent such a fall of transparency, the method of suppressing crystallization to the maximum is mainly used. For example, when high transparency is required, such as a carbonated beverage container, a small amount of copolymers such as isophthalic acid (IPA) is used to reduce the crystallinity of PET and prevent crystals from forming even after molding. . However, polymers prepared in this manner may cause problems in dimensional stability when manufactured as optical biaxially oriented films.

In addition, as a method of reducing the size of the crystal, such as sodium benzoate A method of adding a nucleating agent is also used. However, because this method speeds up the overall crystallization rate, when making thick films such as optics, it is not possible to obtain a squeezing effect during cooling in the unstretched sheet fabrication process, and thermal crystals may occur even without stretching and heat treatment. have. Therefore, when the film is stretched, there is a problem that the stretchability is lowered, the thickness uniformity is worsened, and the transparency is lowered even in the final film.

Therefore, there is a demand for the development of a polyester film having both dimensional stability and transparency by having a minimum crystal size while maintaining a sufficient degree of crystallinity regardless of the processing method and shape. SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester composition excellent in color and transparency that can be used for the preparation of an optical biaxially stretched polyester film, and a method for producing the same.

In accordance with the above object, the present invention provides a polymer comprising a polymer in which an aliphatic catalyst is polycondensed with ethylene glycol, an aliphatic dihydric alcohol, terephthalic acid or dimethyl terephthalate, and an aromatic dihydric acid and a polyfunctional compound having a trivalent or more semi-ungung group. As the ester composition, the polyfunctional compound is contained in an amount of 50 to 2500 ppm, the difference between the color tone L value and the b value is 55 or more, and an extreme limit with the polyester composition having the same melt viscosity and composition without containing the polyfunctional compound. It provides a polyester composition, wherein the difference in viscosity is 0.015 dL / g or less.

According to another object of the present invention, the present invention comprises the step of reacting the esterification by mixing ethylene glycol which is an aliphatic dihydric alcohol and terephthalic acid or dimethyl terephthalate which is an aromatic divalent acid, and the reaction product is polymerized by an antimony catalyst. In the method for producing a polyester composition comprising the step of obtaining a final polymer composition, 50 to 2500 polyfunctional compounds having a trivalent or more semi-ungung group at the beginning or end of the esterification reaction step, or at the beginning of the polymerization reaction step It provides a method of producing a polyester composition, comprising the step of adding the reaction in ppm.

The polyester polymer composition of the present invention is excellent in color and transparency than conventional polymers, and maintains excellent color and transparency even after processing, so that it can be processed into a polyester film or a transparent container to exhibit excellent performance. . DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in more detail.

The present invention is a polyester composition comprising ethylene glycol which is an aliphatic dihydric alcohol, terephthalic acid or dimethyl terephthalate which is an aromatic dihydric acid, and a polymer in which a polyfunctional compound having a trivalent or more semi-ungung group is polycondensed by an antimony-based catalyst, 50 to 2500 ppm of the multifunctional compound is contained, the difference between the tint L value and the b value is 55 or more, the difference in the ultimate viscosity with the polyester composition having the same melting viscosity and composition without containing the polyfunctional compound is 0.015 It provides a polyester composition that is dL / g or less.

When the polyfunctional compound is added below 50ppm, the effect of improving color and transparency is not sufficient, and when it is added more than 2500ppm, the effect of improving color or transparency is not obtained, and the degree of polymerization of the actual polymer (extreme viscosity) It is not preferable because the melt viscosity rises too much compared to), and the adverse effect is obtained due to high shear shear during the melt extrusion process of the polymerization process and film forming. More preferably, the polyfunctional compound is in the range of 150 to 2000 ppm It is good to add.

In the composition of the present invention, the difference between the L value indicating the whiteness and the b value indicating the yellowness in the color index measured by the color meter indicates 55 or more, and preferably may have a difference value of 55 to 65. The larger the difference between the L value and the b value, the better. If the difference is less than 55, the brightness is not required by the present invention.

The excellent color and transparency of the polyester composition of the present invention are believed to be due to the action of the polyfunctional compound added during polymerization on the crystal structure. That is, it is presumed that the polyfunctional compound increases the crystallinity by producing very small crystals as the crystals restrict the growth of large crystals.

In addition, the composition of the present invention exhibits a difference (additional viscosity) of intrinsic viscosity from the polyester composition having the same composition and melt viscosity and no polyfunctional compound (0.01 dL / g or less), preferably 0 To 0.015 dL / g. If the value of the viscosity exceeds 0.015 dL / g, the point at the end of the reaction in the polymerization step should be changed, especially in the case of continuous polymerization, it is difficult to produce a polymer having an accurate degree of polymerization. In addition, deterioration occurs due to excessive shear force (shear) in the release of the melt pressure in the film manufacturing process is not preferable because it is a problem. In order to measure the viscosity, a composition was prepared with the same ingredients and contents as the composition of the present invention, but the polymer was prepared without the addition of a polyfunctional compound to prepare a polymer. do. At this time, it is necessary to terminate the reaction at the same stirring power value during the polymerization reaction so as to have the same melt viscosity as the composition of the present invention.

The multifunctional compound used in the present invention is not particularly limited as a compound having a trivalent or higher acid component or a trivalent or higher alcohol component. However, when the molecular weight of the multifunctional compound is too high, the effect of color improvement is improved even in a small amount. Without this, the melt viscosity of the polymer may rise too much, causing process problems in the polymerization step and the melt extrusion step for producing the film. Examples of preferred multifunctional compounds used in the present invention include tris-2-hydroxyethyl isocyanurate (THIC), pentaerythritol (PEL), trimellitic acid (trimellitic). acid, TMA) and combinations thereof.

In order to improve the traveling property of a film, a running property improving agent can be added to the composition of this invention. The runnability enhancer is not particularly limited, but inorganic particles or organic particles may be used. For example, an appropriate amount of inorganic particles such as silica gel, calcium carbonate, and alumina having an average particle diameter of 0.1 to 10.0 / may be included in consideration of optical properties of the film. It is good to let.

In addition, each polymer may further contain additives required for post-processing applications. For example, when it is aimed at producing a biaxially oriented film, an appropriate amount of metal acetate may be added as an electrostatic agent to produce an unstretched sheet.

In addition, in the case of manufacturing a beverage bottle or a container, it is also possible to further increase the degree of polymerization by solid-phase polymerization at a temperature slightly lower than the melting temperature in a solid chip state after melt polymerization.

In addition to the main repeating unit, the polyester composition of the present invention may contain 15% by weight or less of repeating units polymerized from other divalent acid and diol components. There is no need to limit it, but it is preferable to select a component that lowers the crystallinity and does not excessively increase the shrinkage after heat setting of the film manufacturing process. As other divalent acid components that may be used in the film of the present invention, isophthalic acid (IPA), succinic acid, glutaric acid, adipic acid, schweric acid ( suberic acid), azel One or more kinds of azelaic acid, sebacic acid and ester derivatives thereof can be used. As other diol components, ethylene glycol (EG) ᅳ di ethylene glycol (DEG), neopentyl glycol (NPG), propylene glycol (PG), 1,4-butanediol (1,4-BDO), pentanediol, nucleic acid Diol, 2,2-butylethyl-1,3-propanediol (BEPD), 2-methyl-1,3-propanediol (MPDiol), 1,4-cyclonucleodimethanol (1,4-CHDM) 1 or more types can be used. When these components are contained in a film, a single polymer obtained by copolymerizing the respective components may be applied, or various polymers may be used in combination so as to contain the respective compositions. Such a polyester composition of the present invention, esterification of ethylene glycol, which is an aliphatic dihydric alcohol, and terephthalic acid or dimethyl terephthalate, which is an aromatic dihydric acid, and polymerization reaction of the reaction product by an antimony-based catalyst to give a final polymer. In the method for producing a polyester composition comprising the step of obtaining a composition, 50 to 2500 ppm of a polyfunctional compound having a trivalent or more semi-atom group at the beginning or end of the esterification reaction step, or at the beginning of the polymerization reaction step. It is prepared by a method comprising the step of adding and reacting.

In the method for preparing a polyester composition, the polyfunctional compound is preferably added at the beginning of the esterification reaction step, and the esterification reaction step is preferably carried out while removing water as a by-product. In this, it is preferable to use a melt polymerization reaction.

In addition, the multifunctional compound is tris-2-hydroxyethyl isocyanurate (THIC), pentaerythritol (pentaerythritol, PEL), trimellitic acid (TMA) and It is preferable to select from the group which consists of these mixtures. The polyester composition of the present invention can be produced as a biaxially stretched polyester film through a melt extrusion and biaxial stretching process, the film thus produced has a light transmittance of 70% or more at 350nm measured in accordance with ASTM D 1003 It can represent more than 86% at 450nm.

Such a biaxially stretched polyester film comprises the steps of: melt extruding and rapidly solidifying the polyester composition of the present invention to obtain an unstretched sheet; Stretching the unstretched sheet in the longitudinal and transverse directions and then relaxing and heat-setting to obtain a stretched sheet; And cooling the stretched sheet. The polyester polymer of the present invention described so far has excellent color and transparency, and in particular, even if the antimony-based catalyst and phosphorus-based stabilizer are used as it is, no degradation in color and transparency occurs. As a result, it maintains excellent color and transparency even after processing, and thus can be used in a variety of applications requiring transparent containers, polyester films, and other transparency. Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are merely to illustrate the present invention, but not to limit the content of the present invention. Preparation of Polyester Compositions Examples 1-4 and Comparative Examples 1 and 2

Esterification reaction vessel (primary reaction vessel) equipped with a layered separation tower capable of stirring at 200 rpm and separating ethylene glycol and water from the reaction mixture, and Polyethylene terephthalate polycondensation semi-rigidizer with both inverter type stirrer capable of stirring at 10-50 rpm and condensation polymerization reactor (secondary reactor) equipped with vacuum pump and vacuum pump It was used as manure.

100 mol parts of terephthalic acid and 120 mol parts of ethylene glycol were added to the first reaction vessel, and pentaerythritol (PEL) was added in an amount of 25, 50, 500, 1500, 2500 and 3000 ppm relative to the total polymer as a polyfunctional compound. ， Pressurized nitrogen to 1.2kgf / oif and warmed up to remove the byproduct water for about 4 hours at 25CTC to complete the first esterification reaction.

After completion of reaction, triethylphosphate (TEP) was added as a stabilizer to 230 ppm based on the total polymer-to-phosphorus (P) component and stirred for about 5 minutes. Thereafter, as a polymerization catalyst, antimony trioxide (Sb ₂ 0 ₃ ) was added in an amount of 190 ppm based on antimony (Sb) relative to the entire polymer, and stirred for about 5 minutes. The primary reaction product thus obtained was transferred to a secondary reaction machine to carry out polymerization reaction under vacuum of 28 C and 0.5 torr or less. The reaction was terminated when the load of the stirrer motor became 20 kW to obtain the final polyester composition.

The properties of each polyester composition thus obtained are summarized in Table 1 below. Comparative Example 3 A polyester composition was obtained by adding the pentaerythrite, a polyfunctional compound, in the same manner as in Example except that (PEL) was not added. The intrinsic viscosity (IV) of the polyester composition thus obtained was measured and used as the reference value for derivation of the viscosity. Preparation of Biaxially Stretched Polyester Film In order to evaluate the light transmittance of the polymer obtained by the method of Examples 1 to 4 and Comparative Examples 1 to 3, a biaxially stretched film was obtained as follows.

First, each polymer was precrystallized in a paddle dryer at a temperature of 12 CTC and then dried in a tower dryer using 18 CTC dry air. It was melt extruded at 285 ^° C. and then quenched from above with cooling maintained at 26 ^° C. through a T-die to obtain an amorphous sheet.

The amorphous sheet was stretched 3.2 times in the longitudinal direction using the circumferential speed difference between in a stretching roll at 100 ^° C. while auxiliary heating with a radiator heater. This was preheated while rising to 110-12CTC in the tenter, and stretched 3.6 times in the transverse direction under the hot air through the stretching section divided into 13CTC and 14CC.

The stretched sheet was heat-set in a hot air at 230 ^° C., and then cooled with 3.5% relaxation at 18 CTC to obtain a biaxially stretched polyester film having a thickness of 185 iin.

The light transmittances at 380 nm and 450 nm for each film thus obtained are shown in Table 1 below. Evaluation of Properties of Polyester Compositions and Films The properties of the compositions obtained by the examples or comparative examples of the present invention or films prepared using the same were evaluated in the following manner.

(1) limit viscosity (IV) After dissolving each polymer composition in an orthochlorophenol (OCP) solution, the ultimate viscosity value of the polymer was obtained by measuring the dropping time in a Ubelrod tube at a temperature of 30 ^° C. (2) Viscosity Viscosity (Difference Value from Intrinsic Viscosity of Reference Polyester) The polyester composition of Comparative Example 3, in which the reaction was terminated when the stirrer motor power reached 20 kW while polymerizing in a conventional manner without adding a polyfunctional compound. The ultimate viscosity (IV) of was measured and set as the reference value. Intrinsic viscosity (IV) of each of the polyester compositions of Examples 1 to 4 and Comparative Examples 1 and 2, in which the reaction was terminated when the polyfunctional compound was added and the polymerization proceeded to reach the same 20 kW. Was measured and the difference value in the said reference value was made into a viscosity. (3) Polymer Hue Each polymer composition was measured in reflection mode through color meter (Model: SE2000, Nippondenshoku) to obtain whiteness (L) and yellowness (b), respectively. The average value was taken.

(4) Light transmittance of the film Each biaxially stretched polyester film processed using the polyester composition of the Examples and Comparative Examples was 350 using a light transmittance meter (Model: Utrascan PRO, Hunterlab) according to ASTM D 1003 Light for wavelengths from 800 nm The transmittance was obtained. Although the difference is relatively small in the long wavelength region of 500 nm or more depending on the sample, the difference in light transmittance was apparent in the short wavelength region of 450 nm or less, and the light transmittance was compared at wavelengths of 350 nm and 450 nm for evaluation.

As can be seen in Table 1, the polyester composition according to Examples 1 to 4 of the present invention exhibited excellent color tone (Lb) and viscosity, and produced a biaxially stretched polyester film The excellent light transmittance was shown at 350 nm and 450 nm. On the other hand, the polyester compositions according to Comparative Examples 1 and 3 with little or no addition of the multifunctional compound appeared poor in terms of color tone (Lb) and light transmittance of the film. In addition, the polyester composition according to Comparative Example 2 in which the polyfunctional compound was added in excess was poor in terms of viscosity. In the above, the present invention has been described with reference to the above embodiments, which are only examples, and the present invention includes various modifications and other equivalent embodiments that are obvious to those skilled in the art. It should be understood that they can be performed within the scope of the appended claims.

Claims

Claim range

1.A polyester composition comprising ethylene glycol which is an aliphatic dihydric alcohol, terephthalic acid or dimethyl terephthalate which is an aromatic dihydric acid, and a polymer in which a polyfunctional compound having a trivalent or more semi-ungung group is expanded and condensed with an antimony-based catalyst,

50 to 2500 ppm of the polyfunctional compound is contained, the difference between the tint L value and the b value is 55 or more, the difference in the ultimate viscosity with the polyester composition having the same melt viscosity and composition without containing the polyfunctional compound is 0.015 A polyester composition, which is dL / g or less.

2. The method of paragraph 1,

The polyfunctional compound is a polyester composition, characterized in that the compound having a trivalent or higher acid component or a trivalent or higher alcohol component.

3. The method of paragraph 1,

The polyfunctional compounds include tris-2-hydroxyethyl isocyanurate (THIC), pentaerythritol (PEL), trimellitic acid (TA) and their Polyester composition, characterized in that selected from the group consisting of.

4. The method of paragraph 1,

The polyester composition, characterized in that it further comprises a metal acetate as an electrostatic agent, polyester composition.

5. The method of paragraph 1, The polyester composition, characterized in that it further comprises silica gel, calcium carbonate or alumina particles having an average particle diameter of 0.1 to 10.0 / Λη, polyester composition.

6. The method of paragraph 1,

The polyester composition is,

Isophthalic acid (IPA), succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid and At least one divalent acid component selected from the group consisting of ester derivatives thereof; And

Ethylene glycol (EG), diethylene glycol (DEG), neopentyl glycol (NPG), propylene glycol (PG), 1,4-butanedi (1,4-BDO), pentanediol, nucleic acid di, 2,2 -Butylethyl — 1 selected from the group consisting of 1,3—propanediol (BEPD), 2—methyl-1,3-propanediol (MPDiol) and 1,4-cyclonucleic acid dimethanol (1,4-CHDM) At least one further repeating unit polymerized from at least one diol component,

The polyester composition, characterized in that it further comprises up to 15% by weight based on the total weight of the polyester composition.

7. Ester glycolation of ethylene glycol, an aliphatic dihydric alcohol, and terephthalic acid or dimethyl terephthalate, an aromatic dihydric acid; and polymerization reaction of the reaction product with an antimony-based catalyst to obtain a final polymer composition. In the method for producing the composition,

At the beginning or the end of the esterification reaction step, or at the beginning of the polymerization reaction step, adding a polyfunctional compound having a trivalent or higher reaction step at 50 to 2500 ppm to react the method, preparing a polyester composition .

8. The method of clause 7, wherein

The polyfunctional compound, characterized in that the addition of the esterification reaction step at the beginning, characterized in that the polyester composition production method.

9. The product of clause 7,

The esterification step is characterized in that the reaction by removing the by-product water, polyester manufacturing method.

10. The method of clause 7,

The polymerization reaction step, characterized in that the use of melt polymerization reaction, the method of producing a polyester composition.

11. The method of clause 7,

The polyfunctional compound may include tris-2-hydroxyethyl isocyanurate (THIC), pentaerythritol (PEL), trimellitic acid (TMA) and their Method for producing a polyester composition, characterized in that selected from the group consisting of a mixture.

12. A biaxially stretched polyester film prepared by melt extrusion and biaxially stretching the polyester composition according to item 1, wherein the light transmittance measured according to ASTM D 1003 is at least 70% at 350 nm and at least 86% at 450 nm.