KR20240080456A - Preparing Method for Terephthalate-Based Ester Compound - Google Patents

Abstract

A method for preparing a terephthalate-based ester compound comprises an ester exchange step of reacting polyethylene terephthalate (PET) with a glycol ether compound represented by Chemical Formula 1 in the presence of a catalyst to obtain a terephthalate-based ester compound represented by Chemical Formula 2. According to the present invention, it is possible to recycle waste PET and obtain a plasticizer compound with high profitability from waste PET.

Description

{Preparing Method for Terephthalate-Based Ester Compound}

The present invention relates to a method for producing a terephthalate-based ester compound.

As PET is the most widely used among general synthetic resins, a large amount of PET waste is generated every year, and due to its non-natural decomposition properties, it has recently become a major cause of serious environmental pollution. Accordingly, recycling of PET waste, such as discarded beverage bottles, is emerging as a major concern. There are two main ways to recycle waste PET: physical recycling and chemical recycling. In particular, for chemical recycling, waste PET is depolymerized into BHET (Bis-Hydroxyethyl Terephthalate) material and used as a raw material for PET polymerization. Waste PET can be mainly used as chemically recycled PET (C-rPET) products in terms of recycling resource utilization. However, in the case of C-rPET products, the process is relatively complicated and requires expensive equipment, or the yield of the resulting product is low, resulting in low process efficiency and economic feasibility. Therefore, research into effective recycling methods for waste PET is needed.

In addition, among currently used plasticizer products, some phthalate-based products, such as dioctyl phthalate, are subject to environmental regulations in various product groups due to problems with environmental hormones that disrupt the endocrine system, and this trend is expanding the development and use of eco-friendly plasticizers. I am ordering it. For example, di(2-ethylhexyl)phthalate, one of the commercial plasticizers, is a phthalic acid-based plasticizer, and has the problem of high viscosity and poor flexibility at low temperatures. Therefore, there is a high demand for plasticizers that have low environmental and human hazards and have physical properties equal to or higher than those of existing commercial plasticizers.

Republic of Korea Patent Publication No. 10-2016-0113034

The present invention provides a method for producing a terephthalate-based ester compound. Specifically, the present invention seeks to provide a plasticizer compound from PET flakes or waste PET flakes, with low environmental and human hazard and excellent physical properties.

However, the technical problem to be achieved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

One embodiment of the present invention includes a transesterification step of reacting PET with a glycol ether compound represented by Formula 1 below in the presence of a catalyst to obtain a terephthalate-based ester compound represented by Formula 2 below. , provides a method for producing a terephthalate-based ester compound.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R is each hydrogen; Aryl group having 6 to 20 carbon atoms; Alkylaryl group having 7 to 20 carbon atoms; Or an arylalkyl group having 7 to 20 carbon atoms,

l is an integer from 1 to 10,

m and n are each independently integers from 1 to 10.

The method for producing a terephthalate-based ester compound according to an embodiment of the present invention can produce an eco-friendly plasticizer compound with low environmental and human hazards using PET waste, thereby enabling recycling of waste PET and high profitability from waste PET. There is an advantage in being able to obtain a plasticizer compound having .

In the present invention, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are intended to indicate the presence of one or more other It should be understood that this does not exclude in advance the possibility of the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

The term “alkyl group” as used herein refers to a monovalent straight-chain, branched-chain, or ring-chain saturated hydrocarbon group consisting only of carbon and hydrogen atoms, and includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, etc. Including but not limited to this.

The term “aryl group” as used herein refers to an organic group derived from an aromatic hydrocarbon by removal of one hydrogen, and includes a single or fused ring system. Specific examples of the aryl group include phenyl group, naphthyl group, biphenyl group, anthryl group, fluorenyl group, phenanthryl group, triphenylenyl group, pyrenyl group, perylenyl group, chrysenyl group, naphthacenyl group, and fluorane. It includes, but is not limited to, a tenyl group and the like.

The term “alkylaryl group” as used herein refers to an organic group in which one or more hydrogens of an aryl group are replaced by an alkyl group, such as methylphenyl group, ethylphenyl group, n-propylphenyl group, iso-propylphenyl group, n-butylphenyl group, It includes, but is not limited to, iso-butylphenyl group, tert-butylphenyl group, etc.

The term “arylalkyl group” as used herein refers to an organic group in which one or more hydrogens of an alkyl group are replaced by an aryl group, and includes, but is not limited to, phenylpropyl group, phenylhexyl group, etc.

In this specification, the “alkylaryl group” and “arylalkyl group” may be the same as the examples of the alkyl group and aryl group described above, but are not limited thereto.

Hereinafter, the present invention will be described in detail.

One embodiment of the present invention includes a transesterification step of reacting PET with a glycol ether compound represented by Formula 1 below in the presence of a catalyst to obtain a terephthalate-based ester compound represented by Formula 2 below. , provides a method for producing a terephthalate-based ester compound.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R is each hydrogen; Aryl group having 6 to 20 carbon atoms; Alkylaryl group having 7 to 20 carbon atoms; Or an arylalkyl group having 7 to 20 carbon atoms,

l is an integer from 1 to 10,

m and n are each independently integers from 1 to 10.

According to one embodiment of the present invention, the PET may be PET flakes. Specifically, the PET may be waste PET flakes. The present invention can help in the recycling of PET waste by obtaining a plasticizer compound with low environmental and human hazards using waste PET flakes as a raw material.

According to one embodiment of the present invention, the transesterification step may be to induce a transesterification reaction between PET and a specific glycol ether represented by Formula 1.

According to one embodiment of the present invention, the glycol ether compound is methyl glycol ether (MG, Methyl Glycol), methyl di glycol ether (MDG, Methyl Di Glycol ether), methyl tri glycol ether (MTG, Methyl Tri Glycol ether), Methyl Poly Glycol ether (MPG), Ethyl Glycol ether (EG), Ethyl Di Glycol ether (EDG), Butyl Glycol ether (BG), Butyl Di Glycol ether (BG) Glycol ether (BDG, Butyl Di Glycol ether), Butyl Tri Glycol ether (BTG, Butyl Tri Glycol ether), Butyl Poly Glycol ether (BPG, Butyl Poly Glycol ether), Methyl Propylene Glycol ether (MPG, Methyl Propylene Glycol ether), Methyl Propylene Di Glycol ether (MPDG, Methyl Propylene Di Glycol ether), Methyl Propylene Tri Glycol ether (MPTG, Methyl Propylene Tri Glycol ether), Phenyl Glycol ether (PhG, Phenyl Glycol ether), Phenyl Di Glycol Ether (PhDG, Phenyl Di It may be one glycol ether selected from the group consisting of (glycol ether). Specifically, according to one embodiment of the present invention, the glycol ether compound represented by Formula 1 includes at least one of butyl diglycol ether (BDG, Butyl Diglycol ether) and butyl triglycol ether (BTG, Butyl Triglycol ether). can do. More specifically, the glycol ether compound represented by Formula 1 may be butyl diglycol ether (BDG, Butyl Diglycol ether) or butyl triglycol ether (BTG, Butyl Triglycol ether).

According to an exemplary embodiment of the present invention, the transesterification reaction in the transesterification step may be as shown in the following reaction formula.

[Reaction formula]

The above reaction equation is an example, and the repeating unit n here may be an arbitrary value.

According to an exemplary embodiment of the present invention, the content of PET may be 10% by weight or more and 40% by weight or less, based on the total weight of the PET, catalyst, and glycol ether compound. Specifically, with respect to the total weight of the PET, catalyst, and glycol ether compound, the content of PET may be 10% by weight to 30% by weight, and 15% to 25% by weight. If the PET content is outside the range, the reactivity of the transesterification reaction may decrease, causing a decrease in the yield of the terephthalate-based ester compound.

According to one embodiment of the present invention, the transesterification step may be performed under a temperature range of 200°C or more and 250°C or less. Specifically, the transesterification step may be performed under a temperature range of 210°C or more and 240°C or less. Furthermore, the transesterification step may be performed in the above temperature range for 3 to 7 hours. The reaction time in the transesterification step can be calculated from the time the reactants are heated and reach the temperature range.

According to one embodiment of the present invention, the reaction time in the transesterification step may be performed for 7 to 12 hours. The reaction time in the transesterification step can be calculated from the time the reaction temperature is reached by raising the temperature of the reactants.

According to one embodiment of the present invention, the transesterification step may produce ethylene glycol ether as a reaction by-product. Therefore, the transesterification step needs to remove ethylene glycol ether, a by-product of the reaction.

According to one embodiment of the present invention, the transesterification step may be performed under an inert atmosphere. Specifically, the transesterification step may be performed under a nitrogen atmosphere. Additionally, in order to effectively remove ethylene glycol ether generated as the transesterification step progresses, nitrogen gas, an inert gas, can be directly injected into the reaction solution until the reaction is completed.

According to one embodiment of the present invention, after the transesterification step, the step of removing unreacted glycol ether and reaction by-products may be further included under a vacuum atmosphere and a temperature of 130°C or more and 180°C or less. The product, a terephthalate-based ester compound, may cause yellowing in a high-temperature vacuum atmosphere due to the presence of oxygen atoms in the chain. Therefore, in order to prevent the color change of the product terephthalate ester compound and remove the unreacted glycol ether and the reaction by-product ethylene glycol ether, the reaction temperature in the transesterification step is 130 ℃ or more and 180 ℃ or less. It needs to be performed over a range of temperatures.

According to one embodiment of the present invention, the vacuum atmosphere in the step of removing the unreacted glycol ether compound and reaction by-products may be performed by vacuum decompression with temperature control as described above. At this time, the pressure in the vacuum decompression may be 5 mmHg or less, 3 mmHg or less, or 1 mmHg or less. Additionally, the step of removing the unreacted glycol ether compound and reaction by-products may be performed for 30 minutes to 5 hours under the vacuum conditions and/or temperature range.

According to one embodiment of the present invention, after the transesterification step, a primary filtration step of removing impurities using an aqueous sodium sulfate solution may be further included. The first filtration step may be performed after the step of removing unreacted glycol ether and reaction by-products described above. The product, a terephthalate-based ester compound, has a specific gravity of 1 or more, making it difficult to perform a washing process using water. Therefore, by adding an aqueous sodium sulfate solution, phase separation is induced so that the product, the terephthalate-based ester compound, is located in the upper layer and the impurities are located in the lower layer, and then the lower layer is removed to remove the impurities. More specifically, in the first filtration step, the produced terephthalate-based ester compound is cooled to a temperature of 110°C to 130°C, and 8% to 15% aqueous sodium sulfate solution is added in an amount of 5 to 10 parts by weight based on the terephthalate-based ester compound. After adding in parts by weight, it may be stirred for 2 to 3 hours and impurities in the lower layer may be removed. Then, a process of removing moisture may be added under a vacuum atmosphere for 40 to 80 minutes until a predetermined moisture content is reached.

According to one embodiment of the present invention, after the transesterification step, a secondary filtration step of removing impurities using an adsorbent may be further included. The secondary filtration step is to increase the purity of the prepared isophthalate-based ester compound and can be performed using an adsorbent. As an example, the secondary filtration step may be performed by mixing a powdered adsorbent such as porous silica, diatomaceous earth, and/or white earth with the reaction product to adsorb impurities. At this time, the content of the powdered adsorbent may be 1 part by weight or more and 10 parts by weight or less based on 100 parts by weight of the reaction product, but is not limited thereto, and may vary depending on the type of the powdered adsorbent and/or the type of the glycol ether compound. It can be adjusted accordingly.

According to one embodiment of the present invention, the catalyst may be a catalyst used in a conventional transesterification step. Specifically, the catalyst may include at least one of an organometallic catalyst and an acid catalyst. More specifically, the organometallic catalyst includes Ti/Sn/Zn-based organometallic catalysts, such as tetra-isobutyl titanate (TIBT), tetra-isopropyl titanate (TIPT), Contains one member selected from the group consisting of dibutyl tin oxide (DBTO), monobutyltin oxide (MBTO), tin(II) oxalate, and zinc acetate. can do. Additionally, the acid catalyst may include one selected from the group consisting of paratoluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and sulfuric acid. More specifically, the catalyst in the transesterification step may be tin oxalate (Tin(II) oxalate).

According to one embodiment of the present invention, the content of the catalyst may be 0.1 part by weight to 1 part by weight based on the PET. If it is outside the above range, it may cause a decrease in response efficiency or discoloration of the product.

According to an exemplary embodiment of the present invention, in Formula 2, R ₁ and R ₂ are each independently an alkyl group having 1 to 20 carbon atoms; Alternatively, it may be an aryl group having 6 to 20 carbon atoms. Specifically, R ₁ and R ₂ may each independently be an alkyl group having 1 to 20 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms.

According to an exemplary embodiment of the present invention, R ₁ and R ₂ may each independently be an unsubstituted straight-chain or branched alkyl group of 1 to 20 atoms.

According to an exemplary embodiment of the present invention, in Formula 2, R ₁ and R ₂ may be the same or different from each other.

According to an exemplary embodiment of the present invention, in Formula 2, m and n may each independently be an integer of 1 to 7, an integer of 1 to 5, and specifically an integer of 1 to 3.

According to an exemplary embodiment of the present invention, in Formula 2, m and n may be the same or different from each other. According to an exemplary embodiment of the present invention, Formula 2 may be the following Formula 2-1 or 2-2.

[Formula 2-1]

[Formula 2-2]

According to an exemplary embodiment of the present invention, through the above production method, the terephthalate-based ester compound can be obtained with an acid value of 0.1 KOHmg/g or less, a moisture content of 1,000 ppm or less, and a purity of 95% or more.

One embodiment of the present invention provides a terephthalate-based ester compound represented by Formula 2, prepared by the above-described production method.

Furthermore, another embodiment of the present invention provides a resin composition containing the above terephthalate-based ester compound and a resin as a plasticizer. As described above, the terephthalate-based ester compound according to the present invention is not a substance harmful to the human body such as environmental hormones, so it can minimize the human hazard when applied as a plasticizer, and has physical properties equivalent to or better than those of commercial plasticizers. Furthermore, the terephthalate-based ester compound according to the present invention can suppress yellowing and achieve excellent physical properties in appearance.

According to one embodiment of the present invention, the resin may be a resin known in the field of plasticizer application. For example, a mixture of one or more types selected from polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), thermoplastic elastomer, and polylactic acid may be used, but is not limited thereto.

According to one embodiment of the present invention, the resin in the resin composition is a polyvinyl chloride (PVC) resin, and the content of the terephthalate-based ester compound is 5 to 120 parts by weight, or 40 parts by weight, based on 100 parts by weight of the resin. It may be from 80 parts by weight to 80 parts by weight. If the content is less than the above content, the viscosity of the compound formulation is low and processability may be reduced, and if the content is more than the above content, a bleeding effect (a phenomenon in which the plasticizer comes out to the surface of the molded product) may occur.

According to one embodiment of the present invention, the resin composition may further include a stabilizer and an auxiliary stabilizer as needed, and the additive may be a stabilizer (Barium zinc) and stearic acid, and the amount is 0 to 100 parts by weight based on 100 parts by weight of the resin. It may be 20 parts by weight, preferably 1 to 5 parts by weight.

Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be illustrated in the drawings and explained in detail in the detailed description below. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

[Example 1]

Add 170 g of PET flakes (about 19.5 wt%) and 700 g of butyl diglycol ether (BDG) into a 500 ml four-necked round bottom flask equipped with a stirrer and condenser, and add a titanium-based catalyst (TIPT, tetra). A transesterification reaction was performed by adding 0.51 g (0.3 parts by weight compared to PET flake) of isopropyl titanate). At this time, the reaction temperature was slowly raised and stirred at a speed of 100 rpm for 10 hours at about 230°C, and nitrogen gas was directly added to the reaction solution at a flow rate of 100 cc/min to remove ethylene glycol ether, a reaction by-product.

Then, the temperature of the reaction solution was lowered to about 160°C, and unreacted glycol ether (BDG) and residual ethylene glycol ether were removed under reduced vacuum pressure (<1 mmHg) for 3 hours.

In order to remove impurities in the reaction product, the temperature of the reaction solution was lowered to about 120°C, about 50 mL of 10% aqueous sodium sulfate solution was added, and the mixture was stirred for about 2 hours. Then, the lower layer liquid containing impurities was separated and removed. Then, moisture was removed under a vacuum atmosphere for about 60 minutes until the moisture content was below an appropriate level.

Finally, for decolorization and purification, about 10 g of powdered adsorption media based on porous silica was added, stirred for about 30 minutes, and then filtered to obtain an acid value of about 0.1 KOHmg/g or less, purity of 97.9%, and color ( APHA) The eco-friendly plasticizer di-butyl-diglycol terephthalate (DBDTP) with a value of 128 was obtained.

[Example 2]

Proceeding in the same manner as in Example 1, except that butyl triglycol ether (BTG) was used instead of butyl diglycol ether (BDG), a DI having a purity of 98.1% and a color (APHA) of 157 was obtained. -Butyl-triglycol terephthalate (Di-butyl triglycol terephthalate, DBTTP) was obtained.

[Example 3]

Proceeding in the same manner as Example 1, except that zinc acetate, a zinc-based catalyst, was used instead of the titanium-based catalyst (TIPT, tetra isopropyl titanate), the plasticizer di-butyl with a purity of 95.2% and a color (APHA) of 95 was used. -Di-butyl diglycol terephthalate (DBDTP) was obtained.

[Example 4]

Proceeding in the same manner as Example 2, except that zinc acetate, a zinc-based catalyst, was used instead of the titanium-based catalyst (TIPT, tetra isopropyl titanate), di-butyl-purity 96.5% and color (APHA) 108 were obtained. Triglycol terephthalate (Di-butyl triglycol terephthalate, DBTTP) was obtained.

[Example 5]

Proceeded in the same manner as Example 1, except that Tin(II) oxalate, a tin-based catalyst, was applied instead of titanium-based catalyst (TIPT, tetra isopropyl titanate), and purity was 99.1% and color (APHA) was 34. Di-butyl diglycol terephthalate (DBDTP) was obtained.

[Example 6]

Proceeding in the same manner as in Example 2, except that Tin(II) oxalate, a tin-based catalyst, was applied instead of the titanium-based catalyst (TIPT, tetra isopropyl titanate), a plasticizer with a purity of 99.5% and a color (APHA) of 42 was obtained. Di-butyl triglycol terephthalate (DBTTP) was obtained.

The physical properties of the isophthalate-based ester compounds obtained according to Examples 1 to 6 were shown in Table 1 below.

reaction product water
(%) color
(APHA) Sanga
(KOHmg/g) moisture
(ppm) Example 1 DBDTP 97.9 128 0.07 452 Example 2 DBTTP 98.1 157 0.09 432 Example 3 DBDTP 95.2 95 0.08 725 Example 4 DBTTP 96.5 108 0.06 458 Example 5 DBDTP 99.1 34 0.07 716 Example 6 DBTTP 99.5 42 0.05 480

- Purity (%): Purity (Ester Content) of the sample was analyzed by gas chromatography (GC-Mass analyzer) according to ASTM D3465.

- Color (APHA): APHA (American Public Health Association) color measurement was conducted in accordance with JIS K6751/D5386, and the APHA COLOR value was confirmed with the naked eye using Pt/Co standard reagent.

- Acid value (KOH mg/g): According to JIS K 6751, dissolve 1 g to 5 g of sample in isopropyl alcohol, add 2 to 3 drops of phenolphthalein solution, and then dissolve it to 0.1. It was titrated with an aqueous potassium hydroxide (KOH) solution of N concentration, and the acid value was measured using the following calculation formula.

Acid Value = (appropriate amount Х 5.6 Х factor)/sample amount

Here, the titration amount is the consumption amount (ml) of the KOH aqueous solution of 0.1 N concentration used in the titration, the factor is the correction coefficient of the KOH aqueous solution (factor = 1 for the KOH aqueous solution of 0.1 N concentration), and the sample amount is the weight of the sample. it means.

- Moisture (ppm): Moisture content in the sample (Moisture content by Karl Fischer) was measured according to ASTM D1364.

According to Table 1, it was found that Examples 1 to 6 all had excellent purity, color, acid value, and moisture content, and in particular, Examples 1 to 6 were prepared by applying tin oxalate (Tin(II) oxalate), a tin-based catalyst. It was confirmed that Examples 5 and 6 showed the highest purity and color (APHA) values.

[Application example 1]

Di-butyl diglycol terephthalate (DBDTP) synthesized in Example 5 was added by content (0, 10, 30, 50 parts by weight) to 100 parts by weight of polyvinyl chloride (PVC) resin. The characteristics of each resin are listed in Table 2.

[Application example 2]

Di-butyl triglycol terephthalate (DBTTP) synthesized in Example 6 was added by content (0, 10, 30, 50 parts by weight) to 100 parts by weight of polyvinyl chloride (PVC) resin. , the characteristics of each resin are listed in Table 2.

Plasticizer content
(part by weight) Tg
(℃) PVC - 84.1 Application example 1
(DBDTP) 10 69.1 30 39.9 50 29.0 Application example 2
(DBTTP) 10 61.2 30 35.2 50 20.2

The Tg was measured with a differential scanning calorimeter (DSC-Q200 (TA Instruments)) at a temperature increase rate of 10°C/min. The lower the Tg, the better the plasticization efficiency.

According to Table 2, when the terephthalate-based ester compound according to the example was added to the PVC resin as a plasticizer, as the content of the plasticizer increased, the Tg gradually lowered to the point where the flexibility of the PVC resin could be secured. This means that the free volume of the polymer chain increases when the structure of the alcohol that occupies the non-polar part of the plasticizer becomes longer or has a more complex structure. As the content of the terephthalate-based ester compound according to the example increases, plasticization increases. It was confirmed that efficiency was improved.

[Application example 3]

Based on 100 parts by weight of polyvinyl chloride (PVC) resin, 50 parts by weight of di-butyl diglycol terephthalate (DBDTP) plasticizer synthesized in Example 5, 5 parts by weight of stabilizer (Barium zinc), and stearic acid. 0.3 parts by weight were mixed. Then, a roll mill was used to work at 170 ℃ for 5 minutes, and a press was used to work at 180 ℃ for 5 minutes (low pressure) and 2 minutes (high pressure) to produce a sheet with a thickness of 3 mm. did.

[Application example 4]

A sheet was manufactured in the same manner as Application Example 3, except that di-butyl triglycol terephthalate (DBTTP) synthesized in Example 6 was used as a plasticizer.

[Comparative Application Example 1]

A sheet was manufactured in the same manner as Application Example 3, except that Dioctyl terephthalate (DOTP) was used as a plasticizer.

[Comparative Application Example 2]

A sheet was manufactured in the same manner as Application Example 3, except that diethyl hexylcyclohexane (DEHCH) was used as a plasticizer.

The physical properties of the sheets according to Application Examples 3 and 4 and Comparative Application Examples 1 and 2 are shown in Table 3.

Application example 3
(DBDTP) Application example 4
(DBTTP) Comparative application example 1
(DOTP) Comparative application example 2
(DEHCH) Hardness (Shore A) 80.8 79.6 86.1 79.1 Sheet heating loss (%) 0.18 0.12 0.52 0.89 Fulfillment loss (%) 0.3 0.2 1.5 0.7 Tensile strength (kgf/cm2) 246 254 225 220 Elongation (%) 358 352 306 322

- Hardness (ASTM D2240): To measure shore A hardness, the hardness tester ("C" type) needle was fully lowered into the specimen (3T) and the hardness value that appeared 10 seconds later was read. Hardness was tested at three locations for each specimen and then the average value was calculated.

- Sheet heating loss: After working the prepared specimen at 100°C for 72 hours, the weight of the specimen was measured.

Sheet heating loss (% by weight) = initial specimen weight - (100℃, specimen weight after 72 hours of work) / initial specimen weight Х 100

- Migration loss (migration resistance): An oil-absorbing film made of polypropylene was placed on/under the PVC sheet, and a load of 2 kg was applied at 80°C to promote migration of the plasticizer. After being left for 3 days, the change in weight of the film was calculated.

Transition loss = (Initial film weight - Film weight after transition) / (Initial film weight) x 100.

- Tensile strength (ASTM D638): Using INSTRON's UTM 4466 tensile tester, the cross head speed was pulled to 200 mm/min, and then the point where the specimen was cut was measured.

Tensile strength (kgf/㎟) = load value (kgf) / thickness (mm) Х width (mm)

- Elongation (ASTM D882): The elongation until the sheet breaks under the same conditions as the above tensile strength was determined.

Elongation (%) = length after stretching / initial length Х 100

According to Table 3, the physical properties of the polyvinyl chloride resin film using the terephthalate-based ester compound synthesized according to Examples 5 and 6 as a plasticizer are the physical properties of the polyvinyl chloride resin film using DOTP or DEHCH, which are existing commercialized plasticizers. In comparison, the hardness, tensile strength, and elongation were at the same level or higher, and in particular, sheet heating loss and migration loss were confirmed to have superior physical properties compared to existing commercialized plasticizers.

Claims (7)

In the presence of a catalyst, PET (Polyethylene terephthalate) is reacted with a glycol ether compound represented by the following Chemical Formula 1, to obtain a terephthalate-based ester compound represented by the following Chemical Formula 2, a terephthalate-based ester exchange step comprising: Method for producing ester compounds:
[Formula 1]

[Formula 2]

In Formulas 1 and 2,
R is each hydrogen; Aryl group having 6 to 20 carbon atoms; Alkylaryl group having 7 to 20 carbon atoms; Or an arylalkyl group having 7 to 20 carbon atoms,
l is an integer from 1 to 10,
m and n are each independently integers from 1 to 10. In claim 1,
A method for producing a terephthalate-based ester compound, wherein the glycol ether compound represented by Formula 1 includes at least one of butyl diglycol ether (BDG, Butyl Diglycol ether) and butyl triglycol ether (BTG, Butyl Triglycol ether). . In claim 1,
A method for producing a terephthalate-based ester compound, wherein the content of PET is 10% by weight or more and 40% by weight or less, based on the total weight of the PET, catalyst, and glycol ether compound. In claim 1,
A method for producing a terephthalate-based ester compound, wherein the reaction temperature in the transesterification step is 200 ℃ or more and 250 ℃ or less. In claim 1,
After the transesterification step, the method for producing a terephthalate-based ester compound further includes the step of removing unreacted glycol ether and reaction by-products at a temperature of 130 ℃ or more and 180 ℃ or less and a vacuum atmosphere. In claim 1,
After the transesterification step, a first filtration step of removing impurities using an aqueous sodium sulfate solution; and a secondary filtration step of removing impurities using an adsorbent. In claim 1,
A method for producing a terephthalate-based ester compound, wherein the PET is waste PET flakes.