WO2008140177A1

WO2008140177A1 - Composition of terephthalic acid esters for polymer resin and method of manufacturing the same

Info

Publication number: WO2008140177A1
Application number: PCT/KR2008/000992
Authority: WO
Inventors: Byoung-Kue Chun; Kye-Seok Lee; Sang-Oeb Na; Chil-Eui Hong; Kyu-Il Lee; Dong-Hwa Gong; Jae-Koo Kim; Ok-Sun Kim; Mi-Young Kim
Original assignee: Lg Chem, Ltd.
Priority date: 2007-05-11
Filing date: 2008-02-20
Publication date: 2008-11-20
Also published as: KR100868194B1; CN101679708A; CN101679708B

Abstract

The present invention provides a terephthalic acid ester composition comprising at least three different terephthalic acid compounds. In this composition, at least one of those three different compounds has the terephthalic add with a different substituent and at least two of those compounds have the terephthalic acid with an identical substituent, the molar ratio of the compound having the terephthalic add with an identical substituent is 6 - 80 mol% for the total mol of the composition, and the molar ratio of the compound having the terephthalic add with a different substituent is 20 - 94 mol%. The composition of the present invention increases physical properties of polymer resin molded product including tensile strength, heating loss, elongation, age resistance and weatherability when it is added as a plastidzer during the processing of polyvinylchloride resin

Description

COMPOSITION OF TEREPHTHALIC ACID ESTERS FOR POLYMER RESIN AND METHOD OF MANUFACTURING THE

SAME

Technical Field

[1] The present invention relates to a terephthalic acid ester composition as a potential plastidzer and a preparing method of the same, more precisely a terephthalic acid ester composition which can improve properties of polymer resin molded product including tensile strength, heating loss, elongation, age resistance and weatherability when it is added as a plastidzer during the processing of polymer resin, particularly polyvinyl- chloride resin, and a preparing method of the same. The present invention also relates to a polymer resin composition containing such a plastidzer composition and the polymer resin. Background Art

[2] Polymer resin that has been applied in various fields to serve life convenience is molded by various processing methods and thus used for the production of various householding goods or industrial articles.

[3] In particular, polyvinylchloride resin is the most common resin that can be easily molded by various processing methods such as compound extrusion molding, injection molding, calendering and sol molding, etc. Polyvinylchloride resin can be processed by one of the above methods as materials for various products including pipes, internal or external construction materials, electric wires, electric or mechanical products, toys, films, sheets, synthetic leathers, tapes, food packages and medical supplies.

[4] Various processing properties can be given to the polyvinylchloride resin by adding additives such as plastidzers, secondary plastidzers, stabilizers, pigments, fillers, foaming agents, lubricants, viscosity modifiers, etc. The plastidzer is an additive that plays a role in increasing workability by redudng the coeffident of friction between polymer resins, and different types of plastidzers have been known so far along with their different applications and uses. Most representative plastidzers are phthalate (ortho-phthalate), adipate, phosphate and trimellitate plastidzers, and among them phthalate plastidzer is the most common plastidzer.

[5] Phthalic add anhydride, the raw material of the conventional phthalate plastidzer has an unstable ring structure, which is highly sensitive to the reaction with impurities in addition to water and major material. In the meantime, terephthalic add has a very stable structure so that it can reduce causes of the decrease of purity of the product by secondary reactions. According to the world wide environmental regularity, the conventional phthalate plastidzer has been gradually limited in uses, so selection of raw material has to be reconsidered.

[6] Some of terephthalic add ester compounds have been used as a plastidzer but their properties as a plastidzer have to be improved.

[7] To overcome the above problems, the present inventors paid attention to the point that unlike phthalic add anhydride, small amount of terephthalic add remaining in terephthalic add ester compound used as a plastidzer does not affect quality of the polymer resin product, and thus the terephthalic add can be an excellent substrate candidate transferring various characteristics to the plastidzer because it can be easily bound to various kinds of alcohols. So, the present inventors made an attempt to use terephthalic add, the raw material for PET resin, instead of phthalic add anhydride which has been generally used as a phthalate (ortho-phthalate) plastidzer, in order to increase physical properties to the satisfactory level by taking advantage of the combination of terephthalic add with proper alcohol. Disclosure of Invention Technical Problem

[8] It is an object of the present invention to provide a terephthalic add ester composition that is able to improve properties of polymer resin molded product including tensile strength, heating loss, elongation, age resistance and weatherability by being added as a plastidzer to the polymer resin.

[9] It is another object of the present invention to provide a preparing method of the terephthalic add ester composition.

[10] It is further an object of the present invention to provide a polymer resin composition containing the terephthalic add ester composition. Technical Solution

[11] The above objects of the present invention can be achieved by the following embodiments of the present invention.

[12] The present invention is described in detail hereinafter.

[13] The present invention provides a terephthalic add ester composition containing at least three different compounds selected among terephthalic add ester compounds represented by formula 1. [14] Chemistry Figure 1

[Chem.l]

[15] Wherein, R and R' are independently C3- C12 alkyl, identical or different, and preferably C6 - ClO alkyl.

[16] In the composition of the present invention, at least one of those three different compounds has a terephthalic acid with a different substituent and at least two of those compounds have terephthalic acids with identical substituents. Considering the total mol number of those compounds as standard, the molar rate of the compound comprising the terephthalic add having an identical substituent is 6 - 80 mol% and the molar rate of the compound comprising the terephthalic add having a different substituent is 20 - 94 mol%.

[17] The substituent in terephthalic add hereinbefore and hereinafter indicates not the substituent substituted at benzene ring of terephthalic add but the substituent repladng hydrogen of terephthalic add, which is originated from alcohol in the aspect of the preparing method. In this description, the substituent substituted at benzene ring of terephthalic add is not mentioned, but as long as the terephthalic add ester having such substituent at benzene ring exhibits characteristics of a plastidzer, it can be included in the criteria of the invention or regarded as a component for the composition of the invention or entitled to be a component for the composition of the invention.

[18] The composition of the present invention contains at least three or more terephthalic add ester compounds represented by formulas 2 - 4, predsely it contains 3 - 77 mol% of terephthalic add ester compound represented by formula 2, 20 - 94 mol% of terephthalic add ester compound represented by formula 3, and 3 - 77 mol% of terephthalic add ester compound represented by formula 4.

[19] Chemistry Figure 2

[Chem.2]

R1OOC C00R1

[20] ChemistryFigure 3

[Chem.3]

[21] ChemistryFigure 4

[Chem.4]

[22] Wherein, Rl and R2 are independently different C3 - C 12 alkyl, and preferably independently different C6 - ClOalkyl. [23] The compounds represented by formulas 2 - 4, used as components for the composition of the invention, are preferably:

[24] 1) 1,4-benzenedicarboxylic add bis(2-ethylhexyl)ester; [25] CgHi₇OC OCgH/jC O₂C₈C₁₇

[27] 2) 1,4-benzenedicarboxylic add l-(2-ethylhexyl)-4-(C8-C10 branched alkyl)ester, [28]

[29]

and

[30] 3) 1,4-benzenedicarboxylic add bis(C8-C10 branched alkyl) ester

[33] Herein, the C8-C10 branched alkyl indicates that C9 alkyl is mostly included and small amount of C8 and ClO alkyl, particularly C8, is included. The alkyl herein is originated from isononyl alcohol. The isononyl alcohol is not pure C9 alcohol but the mixture of different C9 alcohols or C9 alcohol fraction that is originated from a fermentation product and includes C8 alcohol and ClO alcohol, particularly small amount of C8 alcohol. So, the isononyl alcohol in the present invention can be understood as C9 alcohol fraction and C9 alkyl in this description can be understood to be originated from the isononyl alcohol.

[34] Therefore, in the above formula, Rl is specifically C8 alkyl, R2 is C9 alkyl comprising small amount of C8 and ClO alkyl. [35] The terephthalic acid ester composition of the present invention can be used as a plasticizer for polymer resin so as to improve properties of polymer resin, particularly polyvinylchloride resin molded product including tensile strength, heating loss, elongation, age resistance and weatherability significantly.

[36] The composition of the present invention comprises at least three different terephthalic add ester compounds. For example, the composition of the invention is composed of the terephthalic add ester compounds having different substituents in their terephthalic adds (substituents are Rl and R2) and the terephthalic add ester compounds having identical substituents in their terephthalic adds (substituents of both are Rl or R2).

[37] These different compounds having different substituents can be differently functioning without damaging plastidty of polymer resin, suggesting that these compounds play a role in enhancement of properties of polymer resin molded product such as tensile strength, heating loss, elongation, age resistance and weatherability significantly but not redudng workability. This enhancement or improvement of plastidty and workability of polymer resin can be realized by regulating the ratio of components of the composition.

[38] The content of each component forming the composition of the invention is preferably regulated in the above mentioned range. If the content of the terephthalic add ester compound having a different substituent represented by formula 3 is too small, the composition will be dominated by the terephthalic add ester compound having an identical substituent represented by formula 2 or 4. Considering that the compound represented by formulas 2 or 4 is used as the conventional plastidzer, the composition of the invention may not be different from the conventional one in its combination of components and characteristics, suggesting that the advantages of the composition of the invention cannot be fully exposed. On the contrary, if the content of the terephthalic add ester compound having an identical substituent represented by formula 3 is too high, the composition having the mentioned component ratio cannot be produced by the following simple preparing method of the invention and instead the complicated production process and unsatisfied productivity remain as problems to be solved.

[39] The substituent of the terephthalic add ester compound that is used as one component of the composition of the invention is preferably alkyl group having proper carbon number. If the alkyl group having smaller number of carbon is used, anti- transitivity will be poor. On the contrary, if the alkyl group having greater number of carbon is used, compatibility with polymer resin will be reduced. Therefore, in the present invention, the substituent is preferably C3 - C 12 alkyl, more preferably C6 - ClO alkyl and most preferably C8 - C9 alkyl.

[40] 'Different substituents' herein include those substituents identical in carbon number but different in structure. Therefore, 2-ethylhexyl and n-octyl have to be understood as 'different substituents' herein. [41] The present invention also provides a preparing method of the terephthalic add ester composition by a single ester reaction. That is, the preparing method of the terephthalic acid ester composition of the invention comprises the steps of reacting terephthalic acid with at least two different alcohols via esterilication, precisely reacting 10 - 40 mol% of terephthalic acid with 60 - 90 mol% of at least two different alcohols having C3 - C12 alkyl in the presence of a catalyst for esterilication; and obtaining the terephthalic acid ester composition.

[42] In this method, when the alcohols are two different alcohols, the molar ratio of the first alcohol to the second alcohol is 1:9 - 9:1. At this time, at least two different alcohols are preferably 2-ethylhexanol and isononyl alcohol and the molar ratio of 2-ethylhexanol to isononyl alcohol is 1:9 - 9:1.

[43] The catalyst herein is preferably a metal alkoxide compound or an acid catalyst, which is particularly a metal alkoxide compound selected from the group consisting of titanate group including tetraisobutyl titanate and tetraisopropyl titanate; and tin group including dibutyl tinoxide or an acid catalyst selected from the group consisting of acids including paratoluene sulfonic acid and sulfuric acid.

[44] The esterification is induced in the presence of nitrogen in order to shut out air flowing from outside of the reaction system. To eliminate water generated during the reaction, bubbling of nitrogen in the reaction solution is preferably induced. The esterification is preferably induced at 200 - 300⁰C for 4 - 24 hours. And the esterification is performed in an organic solvent, particularly in an organic solvent selected from the group consisting of xylene, toluene, dimethylformamide (DMF), n-hexane and benzene.

[45] It is a unique characteristic of the present invention to use the composition comprising at least three different terephthalic acid ester compounds as a plastidzer for the processing of polymer resin, particularly polyvinylchloride resin, to improve properties of polymer resin molded product. The composition of the invention includes at least three different terephthalic add ester compounds prepared by introdudng alkyl substituents originated from at least two different alcohols into two substituents of terephthalic adds via esterification.

[46] Thus, the preparing method of the terephthalic add ester composition of the invention comprises the step of reacting terephthalic add with at least two different alcohols having C3 - C 12 alkyl, more preferably C6 - ClO alkyl, in the presence of a catalyst for esterification.

[47] The preferable content of terephthalic add in the total reactant is 10 - 40 mol%. If the content of terephthalic add is too low, even if the purpose of the invention can be achieved anyhow, excessive alcohol components are necessarily used, suggesting that a bunch of non-reacted alcohol components are remaining wasted or additional efforts have to be made to recover those non-reacted alcohol components which does not favor economic efficiency and productivity. On the contrary, if the content of terephthalic add is too high, non-reacted terephthalic add and the compound having one substituent introduced in terephthalic add (terephthalic add mono-alkyl ester) will be over-produced, which does not favor the productivity and properties of the product even if the excessive components are completely eliminated by purifying process. Theoretically, terephthalic add has two esteriflcation sites, so that the content of alcohol has to be two times the mol of terephthalic add. But, in general, the alcohol which is 1.5 times the terephthalic add can be accepted without causing any of the above mentioned problems. Therefore, the preferable content of terephthalic add is 10 - 40 mol% for the total mol of reactant, and the preferable content of alcohol is 60 - 90 mol% for the total mol of reactant. However, the content is not always limited thereto, since the object of the invention still can be achieved by an additional process, even if the content out of the above range is added for esterification.

[48] The preparing method of the invention is not much different from the conventional esteriflcation except that the reactant of the invention includes at least two different alcohols and the reaction product of the invention includes at least three different terephthalic add ester compounds. Therefore, the method of the invention can be performed under the conventional esterification conditions.

[49] In the present invention, the catalyst for esteriflcation is preferably a metal alkoxide compound or an add catalyst. The metal alkoxide compound can be exemplified by titanium tetraalkoxide [Ti(OR)₄] such as tetraisobutyl titanate and tetraisopropyl titanate; and tin dialkoxide [Sn(OR)₂] such as dibutyl tinoxide. The oxide catalyst can be exemplified by paratoluene sulfonic add and sulfuric add. The preferable content of such catalyst is 0.001 - 1 weight part for 100 weight part of the reaction mixture. If the amount of the catalyst is too small, reaction effidency will be reduced. On the contrary, if the content of the catalyst is too high, discoloration of a product might be induced.

[50] The esterification of the present invention can be performed in an organic solvent, which is exemplified by xylene, toluene, dimethylformamide (DMF), n-hexane and benzene. The esteriflcation is preferably performed at 200 - 300⁰C for 4 - 24 hours in the presence of nitrogen in order to prevent air and moisture from outside of the reaction system. To eliminate water generated by condensation of the esterification, bubbling of nitrogen in the reaction solution is preferably induced. If necessary, the reaction can be performed under vacuum or reduced pressure to achieve other objects.

[51] Upon completion of the esterification, the method of the invention can include a purifying process to eliminate remaining terephthalic acid, small amount though, and non-reacted excessive alcohol components. Particularly, the solvent and non-reacted excessive alcohol can be eliminated by distillation under the reduced pressure. Such elements can also be eliminated by neutralizing terephthalic acid or terephthalic acid mono-alkyl ester by alkali solution and washing thereof. The alkali solution herein is exemplified by 2 - 25% sodium carbonate, 2 - 25% sodium sulfate solution, 2 - 25% potassium hydroxide solution and 2 - 25% sodium hydroxide solution. The elimination of non-reacted elements or byproducts is followed by dehydration using an absorbent. Then, the absorbent is eliminated by filtering to give the composition of the invention.

[52] The method of the invention is characterized by esterification of terephthalic acid and at least two different alcohols in order to prepare the composition comprising at least three different terephthalic acid ester compounds. Compared with the previous method in which the composition is prepared by mixing at least three different terephthalic acid ester compounds prepared separately, the method of the invention has advantages in production, precisely the method realizes simplification of production line, favors productivity and economic efficiency, and provides a plastidzer composition having various physical properties needed for the use for various polymer resins by regulating reaction conditions and concentration or molar ratio of reactants, types and numbers of reactants, etc.

[53] In a preferred embodiment of the invention, terephthalic acid (referred as "HOOC-

TP-COOH" hereinafter) and 2 different alcohols (referred as "RlOH" and "R20H" respectively) were used for esterification. In this example, the product was the mixture of three different terephthalic acid ester compounds, which are R1-00C-TP-C00-R1, R1-OOC-TP-COO-R2 and R2-OOC-TP-COO-R2. At this time, in case each esterification of terephthalic acid at each reaction site was independent, which meant each reaction result did not affect one another, and the content of terephthalic acid was 1 mol and contents of RlOH and R20H were respectively 1 mol, and if the reaction finished completely and the reaction speed of each esterification of RlOH and R20H were equal, the product would be the mixture of

R1-OOC-TP-COO-R1:R1-OOC-TP-COO-R2:R2-OOC-TP-COO-R2 at the ratio of 1:2:1. [54] If the contents of RlOH and R20H are different, for example 0.5 mol and 1.5 mol,

Rl substituted product decreases in number and R2 substituted product increases in number and Rl and R2 substituted product would be generated by a small amount. This result can be expected by regulating the alcohol component ratio. And even when the amount of alcohol added therein is larger than that of terephthalic acid, the consistent result is expected. For example, when RlOH is added by 2 moles and R2OH is added by 3 moles, the ratio of the product will be adjusted aαjording to the ratio of alcohol components.

[55] Reaction speed of RlOH is different from that of R20H. So, in real reaction, the reaction speeds of alcohol components must be an important factor affecting the ratio of components of the reaction product. That is, even if each alcohol component is added by equal amount, if the content of alcohol components is larger than that of terephthalic acid, for example 2 mol of RlOH and 2 mol of R20H are added to 1 mol of terephthalic acid, the alcohol component having fast reaction speed is more substituted than the alcohol component having slow reaction speed.

[56] In actual esterilication, there are still chances that two different reaction sites of terephthalic acid are not completely independent or the reaction cannot be completely finished or other reaction conditions affect differently from expected. Nevertheless, the above presumption is logical, supporting the idea that molar ratio of reactants and reaction speed are major factors affecting the component ratio of the product. Therefore, compositions having the different component ratios can be prepared by regulating such factors in this invention.

[57] If three different alcohols (RlOH, R20H and R30H) are used for esterification, 6 different terephthalic add ester compounds, R1-OOC-TP-COO-R1, R1-OOC-TP-COO-R2, R1-OOC-TP-COO-R3, R2-OOC-TP-COO-R2, R2-OOC-TP-COO-R3 and R3-OOC-TP-COO-R3, are generated. The ratio of these products is affected by the amounts of reactants added and reaction speeds thereof, as mentioned above. If three different alcohols are added by equal amount and the total mol of alcohol is two times the total terephthalic acid and if the reaction is performed completely, the ratio would be 1:2:2:1:2:1. That is, the ratio of total terephthalic acid ester compound having an identical substituent to total terephthalic acid ester compound having a different substituent would be 1:2, suggesting that the total amount of terephthalic acid ester compound having a different substituent would be bigger than that resulted from the reaction using two different alcohols. These characteristics can be considered to select the types of alcohols and to determine the contents of them. [58] In this invention, the ratio of the product can be regulated by using numbers of alcohol components based on the above presumption and conditions, but if too many reactants are taking place in one reaction, the result might be changed by not only major factors expected but also other minor factors, indicating that it is not easy to control the reaction. So, the reaction product generated from the esteriflcation of two different alcohols and the reaction product generated from the other esteriflcation of two or three different alcohols can be mixed at a proper ratio to produce a plasticizer composition having improved physical properties of the invention. This method has various advantages compared with the conventional method in which each component is prepared separately and the prepared components are mixed to produce a composition.

[59] The present invention further provides a polymer resin composition comprising the ester plasticizer composition. In this invention, the content of the plasticizer composition in the polymer resin composition is preferably 5 - 250 weight part for 100 weight part of the polymer resin composition. If the content is less than 5 weight part, workability of the polymer resin will be reduced. On the contrary if the content is more than 250 weight part, physical properties of the composition will be reduced according to the increase of transfer from the polymer resin.

[60] Various additives can be added according to the purpose of use of the polymer resin, to realize the wanted characteristics of the resin. For example, secondary plastidzers, stabilizers, pigments, fillers, foaming agents, lubricants, viscosity modifiers, etc, can be added.

[61] The plasticizer composition of the invention can be applied to the polymer resin exemplified by polyvinylchloride resin, acrylic resin, ABS resin, urethane resin, olefin resin, engineering plastic resin and polyester resin, but not always limited thereto.

[62] The polymer resin composition of the invention can be used for the production of compounds, electric wire compounds, tarpaulins, hoses, profiles, wallpapers, films, food packages, medical supplies, synthetic leathers, sheets, tapes, auto pars, toys, electric or mechanical parts, etc. Best Mode for Carrying Out the Invention

[63] Practical and presently preferred embodiments of the present invention are illustrative as shown in the following Examples.

[64] However, it will be appreciated that those skilled in the art, on consideration of this disclosure, may make modifications and improvements within the spirit and scope of the present invention. [65]

[66] Examples

[67] Example 1

[68] To a 2 liter 4 neck round flask equipped with a stirrer and a condenser were added the reaction mixture prepared by mixing 1.806 mol of terephthalic acid, 3.611 mol of 2-ethylhexanol and 3.611 mol of isononyl alcohol and 0.0042 mol of the catalyst tet- raisopropyl titanate, followed by homogeneous mixing. Temperature was raised to 22O⁰C, followed by reaction for 9 hours in the presence of nitrogen. Upon completion of the reaction, non-reacted substances were eliminated under the reduced pressure at 150 - 22O⁰C. The reaction mixture was then neutralized with 10% sodium hydroxide and washed with 10% sodium sulfate. The reaction mixture was dehydrated under the reduced pressure and filtered to give the ester plastidzer composition. The component ratio of the composition was as follows; 9.8 mol% of 1,4-benzenedicarboxylic acid bis(2-ethylhexyl) ester, 54.2 mol% of 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(isononyl) ester, 36 mol% of 1,4-benzenedicarboxylic acid bis (isononyl) ester.

[69] Example 2

[70] To a 2 liter 4 neck round flask equipped with a stirrer and a condenser was added the reaction mixture prepared by mixing 1.806 mol of terephthalic acid, 3.609 mol of 2-ethylhexanol and 3.611 mol of isononyl alcohol, and the following experiment was performed by the same manner as described in example 1. The component ratio of the composition was as follows; 19.1 mol% of 1,4-benzenedicarboxylic acid bis(2-ethylhexyl) ester, 50.9 mol% of 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(isononyl) ester, 30 mol% of 1,4-benzenedicarboxylic acid bis (isononyl) ester.

[71] Example 3

[72] An experiment was performed by the same manner as described in example 1 except that the reaction mixture prepared by mixing 1.806 mol of terephthalic acid, 5.023 mol of 2-ethylhexanol and 2.162 mol of isononylalcohol was used. The component ratio of the composition was as follows; 37.6 mol% of 1,4-benzenedicarboxylic acid bis(2-ethylhexyl) ester, 47.9 mol% of 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(isononyl) ester, 14.5 mol% of 1,4-benzenedicarboxylic acid bis (isononyl) ester.

[73] Example 4

[74] An experiment was performed by the same manner as described in example 1 except that the reaction mixture prepared by mixing 1.806 mol of terephthalic acid, 5.744 mol of 2-ethylhexanol and 1.44 mol of isononylalcohol was used. The component ratio of the composition was as follows; 56.3 mol% of 1,4-benzenedicarboxylic acid bis(2-ethylhexyl) ester, 38.4 mol% of 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(isononyl) ester, 6.3 mol% of 1,4-benzenedicarboxylic acid bis(isononyl) ester.

[75] Example 5

[76] An experiment was performed by the same manner as described in example 1 except that the reaction mixture prepared by mixing 1.806 mol of terephthalic acid, 6.501 mol of 2-ethylhexanol and 0.722 mol of isononylalcohol was used. The component ratio of the composition was as follows; 64.4 mol% of 1,4-benzenedicarboxylic acid bis(2-ethylhexyl) ester, 25.3 mol% of 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(isononyl) ester, 10.3 mol% of 1,4-benzenedicarboxylic acid bis(isononyl) ester.

[77] The terephthalic acid ester compositions prepared in examples 1 - 5 were used as a plasticizer for the processing of polyvinyl chloride resin samples. The samples were tested for physical properties by the methods described below and the results are shown in Table 1. The content of the plasticizer composition was 42 weight parts for 100 weight part of the polymer resin and no other additives were used.

[78] Comparative Example 1

[79] Samples were prepared by using the conventional plasticizer, di-

2-ethylhexylphthalate, which were tested for physical properties by the same method as described in examples and the results are shown in Table 1.

[80] Comparative Example 2

[81] Samples were prepared by using the conventional plasticizer, dioctylterephthalate, which were tested for physical properties by the same method as described in examples and the results are shown in Table 1.

[82] Table 1 [Table 1]

[83] (Performance evaluation)

[84] The ester plastidzer compositions prepared in examples and comparative examples 1 and 2 were tested for physical properties by the following methods.

[85] Preparation of samples for heating loss and measurement

[86] The composition was prepared as 0.8 mm thick sheet by using roll mill at 165⁰C for

3 minutes. 200 g of the sheet was turned into 0.4 mm thick sample by using a press at 185⁰C for 10 minutes. 24 hours later, the sample was weighed. Heating loss was calculated by the following formula. Heating loss (weight%) = 1 - (weight after the reaction at 185⁰C for 10 minutes) / 20Og x 100.

[87] Preparation of samples for physical properties

[88] The polyvinylchloride resin composition of the invention was prepared as 0.5 mm thick sheet by using roll mill at 18O⁰C for 3 minutes. 200 g of the sheet was used to prepare 1 mm thick sample by using a press at 18O⁰C, 15 MPa for 3 minutes and 10 MPa for 2 minutes.

[89] Tensile strength

[90] Tensile strength was measured by ASTM D638. Particularly, the sample was extended at the cross head speed of 200 mm/min by using the test machine U.T.M. The break point was measured and tensile strength was calculated by the following formula. Tensile strength (kgf/mnf) = load value (kgf) / {thickness (mm) X (mm)}.

[91] Elongation [92] Elongation was measured by ASTM D638. Particularly, the sample was extended at the cross head speed of 200 mm/min by using the test machine U.T.M. The break point was measured and elongation was calculated by the following formula. Elongation (%) = {extension / primary length} X 100.

[93] Tensile strength after heating

[94] The sample was heated in a 100⁰C gear oven for 168 hours and then tensile strength was measured by ASTM D638. Particularly, the sample was extended at the cross head speed of 200 mm/min by using the test machine U.T.M. The break point was measured and tensile strength was calculated by the following formula. Tensile strength (kgf/mnf) = load value (kgf) / {thickness (mm) X (mm)}. The results obtained by ASTM D638 at room temperature were divided by the results obtained after heating, which was represented by %.

[95] Elongation after heating

[96] The sample was heated in a 100⁰C gear oven for 168 hours and then elongation was measured by ASTM D638. Particularly, the sample was extended at the cross head speed of 200 mm/min by using the test machine U.T.M. The break point was measured and elongation was calculated by the following formula. Elongation (%) = {extension / primary length} X 100. The results obtained by ASTM D638 at room temperature were divided by the results obtained after heating, which was represented by %.

[97] The ester plastidzers prepared in examples by using terephthalic acid,

2-ethylhexanol and isononyl alcohol were confirmed to have better physical properties including tensile strength and elongation, in particular excellent heating loss, tensile strength after heating and elongation after heating, compared with the conventional plastidzers of comparative examples 1 and 2. Therefore, unlike other conventional plastidzers, the compositions of the invention can improve aging resistance and weatherability of polymer resin molded product when it is added as a plastidzer. Industrial Applicability

[98] The ester plastidzer composition of the present invention plays a role in improvement of such physical properties as heating loss, weatherability and aging resistance, which had been very poor when the conventional plastidzer was used, and is at the same time functioning as an excellent plastidzer without damaging other physical properties of polymer resin such as elongation and tensile strength.

[99]

[100] Those skilled in the art will appredate that the conceptions and spedfic embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims.

Claims

[1] A terephthalic add ester composition, wherein at least three different compounds selected among terephthalic add ester compounds represented by formula 1 are included, at least one of those three different compounds has the terephthalic add with a different substituent and at least two of those compounds have the terephthalic add with an identical substituent, the molar ratio of the compound having the terephthalic add with an identical substituent is 6 - 80 mol% for the total mol of the composition, and the molar ratio of the compound having the terephthalic add with a different substituent is 20 - 94 mol%. [Chemistry Figure 1]

Wherein, R and R' are independently identical or different C3 - C 12 alkyl.

[2] The terephthalic add ester composition according to claim 1, wherein the composition contains at least three terephthalic add ester compounds represented by formulas 2 - 4, and contains 3 - 77 mol% of terephthalic add ester compound represented by formula 2, 20 - 94 mol% of terephthalic add ester compound represented by formula 3, and 3 - 77 mol% of terephthalic add ester compound represented by formula 4 for the total mol of compounds represented by formulas 2 - 4.

[Chemistry Figure 2]

[Chemistry Figure 3]

[Chemistry Figure 4]

Wherein, Rl and R2 are independently different C3 - C 12 alkyl.

[3] The terephthalic add ester composition according to claim 2, wherein the compounds represented by formulas 2 - 4 are respectively:

1) 1,4-benzenedicarboxylic acid bis (2-ethylhexyl)ester;

C₈H₁₇OCOC₆H₄CO₂C₈C₁₇

2) 1,4-benzenedicarboxylic acid l-(2-ethylhexyl)-4-(C8-C10 branched alkyl)ester,

and

3) 1,4-benzenedicarboxylic acid bis(C8-C10 branched alkyl) ester

[4] The terephthalic acid ester composition according to claim 2, wherein the Rl is C8 alkyl and the R2 is C9 alkyl. [5] The terephthalic add ester composition according to any one of claim 1 - claim

4, wherein the ester composition is used as a plastidzer for the production of polymer resin.

[6] A method for preparing a terephthalic add ester composition comprising the steps of reacting terephthalic add with at least two different alcohols having C3 - C12 alkyl via esteriflcation in the presence of the catalyst for esteriflcation; and obtaining the terephthalic add ester composition containing at least three different compounds selected among those terephthalic add ester compounds represented by formula 1 in which at least one of those three different compounds has the terephthalic add with a different substituent and at least two of those compounds have the terephthalic add with an identical substituent, the molar ratio of the compound having the terephthalic add with an identical substituent is 6 - 80 mol% for the total mol of the composition, and the molar ratio of the compound having the terephthalic add with a different substituent is 20 - 94 mol%. [Chemistry Figure 1]

Wherein, R and R' are independently identical or different C3 - C 12 alkyl.

[7] The method for preparing a terephthalic add ester composition according to claim 6, wherein the content of the terephthalic add is 10 - 40 mol% and the content of the alcohol is 60 - 90 mol% for the total mol of the reactants.

[8] The method for preparing a terephthalic add ester composition according to claim 6, wherein the two different alcohols are 2-ethylhexanol and isononyl alcohol and the ratio of the 2-ethylhexanol to the isononyl alcohol is 1:9 - 9:1.

[9] The method for preparing a terephthalic add ester composition according to claim 6, wherein the catalyst is a metal alkoxide compound or an add catalyst.

[10] The method for preparing a terephthalic add ester composition according to claim 6, wherein the catalyst is a metal alkoxide compound selected from the group consisting of tetraisobutyl titanate, tetraisopropyl titanate and dibutyl tinoxide or an add catalyst selected from the group consisting of paratoluene sulfonic add and sulfuric add.

[11] The method for preparing a terephthalic add ester composition according to claim 6, wherein the esterilication is performed in the presence of nitrogen in order to prevent air from the outside of the reaction system and bubbling of nitrogen is induced in the reaction solution to eliminate water generated during the reaction.

[12] The method for preparing a terephthalic acid ester composition according to claim 6, wherein the esterilication is performed at 200 - 300⁰C.

[13] The method for preparing a terephthalic acid ester composition according to claim 12, wherein the esterilication is performed for 4 - 24 hours.

[14] The method for preparing a terephthalic acid ester composition according to claim 6, wherein the esterilication is performed in an organic solvent selected from the group consisting of xylene, toluene, dimethylformamide (DMF), n- hexane and benzene.

[15] A polymer resin composition comprising 100 weight part of polymer resin and

20 -150 weight part of one of the terephthalic acid ester compositions of claim 1 - claim 5 as a plastidzer.

[16] The polymer resin composition according to claim 15, wherein the polymer resin is selected from the group consisting of polyvinylchloride resin, acrylic resin, ABS resin, urethane resin, olefin resin, engineering plastic resin and polyester resin.

[17] The polymer resin composition according to claim 15, wherein the polymer resin composition additionally includes one or more additives selected from the group consisting of secondary plastidzers, stabilizers, pigments, fillers, foaming agents, lubricants and viscosity modifiers.

[18] The polymer resin composition according to claim 15, wherein the polymer resin composition is used for the production of compounds, electric wire compounds, tarpaulins, hoses, profiles, wallpapers, films, food packages, medical supplies, synthetic leathers, sheets, tapes, auto pars, toys and electric or mechanical parts.