Method for producing thermoplastic polyester elastomer

Abstract

The invention provides a manufacturing method of a thermoplastic polyester elastomer. A polyester recovery is provided, the polyester recovery including polyethylene terephthalate (PET). And carrying out a depolymerization reaction on the polyester recovered material and ethylene glycol. And carrying out transesterification reaction on a product obtained by the depolymerization reaction and aliphatic dihydric alcohol. And carrying out polymerization reaction on a product obtained by the transesterification reaction and long-chain polyalkyl dihydric alcohol to obtain the thermoplastic polyester elastomer. Catalysts used in the depolymerization reaction, the transesterification reaction and the polymerization reaction respectively comprise a chelating titanium catalyst.

Description

Technical Field

[0001] The invention relates to a method for preparing a thermoplastic polyester elastomer, and in particular to a method for preparing a thermoplastic polyester elastomer. Background Art

[0002] Polyester products, including textiles (such as clothes), PET bottles, plastic bags, etc., are widely used in our daily lives, and therefore generate a lot of polyester waste. How to effectively recycle and utilize these polyester wastes is an important issue. Summary of the invention

[0003] The present invention is directed to a method for producing a thermoplastic polyester elastomer, which can effectively recycle discarded polyester products and reduce production costs.

[0004] According to an embodiment of the present invention, a method for manufacturing a thermoplastic polyester elastomer comprises the following steps. A polyester recyclate is provided, wherein the polyester recyclate comprises polyethylene terephthalate. The polyester recyclate is subjected to a depolymerization reaction with ethylene glycol. The product obtained by the depolymerization reaction is subjected to a transesterification reaction with an aliphatic diol. The product obtained by the transesterification reaction is subjected to a polymerization reaction with a long-chain polyalkylene glycol to obtain a thermoplastic polyester elastomer. The catalysts used in the depolymerization reaction, the transesterification reaction and the polymerization reaction each comprise a chelated titanium catalyst.

[0005] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the chelated titanium catalyst is at least one selected from the group consisting of phosphate titanate chelate, citrate titanium chelate and hydroxy acid ester titanate chelate.

[0006] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the catalyst used in the depolymerization reaction, the catalyst used in the transesterification reaction, and the catalyst used in the polymerization reaction are all the same.

[0007] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the long-chain polyalkylene glycol includes polyethylene glycol or polytetramethylene ether glycol.

[0008] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the aliphatic diol is at least one selected from the group consisting of C3 to C10 diols.

[0009] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the product obtained by the transesterification reaction includes dihydroxypropyl terephthalate and / or dihydroxybutyl terephthalate.

[0010] In the method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention, the amount of the long-chain polyalkylene glycol added in the polymerization reaction accounts for 20 wt % to 60 wt % of the total weight of the reactants in the polymerization reaction.

[0011] In the method for manufacturing a thermoplastic polyester elastomer according to an embodiment of the present invention, the above-mentioned polymerization reaction is carried out under a vacuum environment.

[0012] In the method for manufacturing a thermoplastic polyester elastomer according to an embodiment of the present invention, the reaction temperature of the polymerization reaction is between 200 and 300 degrees.

[0013] In the method for manufacturing a thermoplastic polyester elastomer according to an embodiment of the present invention, the method further comprises adding an antioxidant into the polymerization reaction.

[0014] Based on the above, the manufacturing method of the thermoplastic polyester elastomer of the present invention is to obtain the thermoplastic polyester elastomer by subjecting polyester recyclate to depolymerization reaction, transesterification reaction and polymerization reaction, which can effectively recycle the discarded polyethylene terephthalate (PET) and reduce the environmental burden, so as to achieve the effect of environmental protection and circular economy. In addition, the catalysts used in the depolymerization reaction, transesterification reaction and polymerization reaction each include a chelated titanium catalyst, so that a good catalytic effect can be achieved with a small amount of catalyst, thereby reducing the overall manufacturing cost. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are exemplary and the present invention is not limited thereto.

[0016] In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values ​​in the range one by one in the specification. Therefore, the description of a specific numerical range covers any value in the numerical range and a smaller numerical range defined by any value in the numerical range, just as the arbitrary value and the smaller numerical range are written in the description text of the specification.

[0017] The following is an explanation of the embodiments of the present invention through specific specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. The following embodiments will further describe the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention. In addition, the term "or" used herein may include any one or more combinations of the associated listed items depending on the actual situation.

[0018] The following is a detailed description of a method for producing a thermoplastic polyester elastomer according to an embodiment of the present invention.

[0019] First, a polyester recyclate is provided, which includes polyethylene terephthalate (PET). For example, the polyester recyclate can be polyester textiles, PET bottle flakes, or the like. In some embodiments, the polyester recyclate also includes dyes or other impurities.

[0020] In some embodiments, the polyester recyclate may be pre-treated to remove impurities, and the pre-treatment may include, for example, bleaching treatment or other suitable procedures. The bleaching treatment may be performed by, for example, extracting the impurities by immersing the polyester recyclate in an extraction solvent to extract the impurities, thereby achieving a bleaching effect, but the present invention is not limited thereto, as long as the impurities in the polyester recyclate can be removed. In some embodiments, the extraction solvent may be selected from at least one of the group consisting of toluene, xylene, acetic acid, propylene glycol methyl ether, and ethylene glycol.

[0021] Then, the polyester recycle is subjected to a depolymerization reaction. For example, ethylene glycol can be used as a depolymerization liquid to carry out a depolymerization reaction between the polyester recycle and ethylene glycol to obtain a product including ethylene terephthalate (Bis (2-HydroxyEthylTerephthalate), BHET).

[0022] The depolymerization reaction can be carried out in an environment containing a depolymerization catalyst to increase the reaction rate, wherein the depolymerization catalyst can include a chelated titanium catalyst. The chelated titanium catalyst has high activity, is not easily deactivated, and can be evenly dispersed in the depolymerization liquid, so a small amount of catalyst can be used to effectively catalyze the depolymerization reaction. In addition, the chelated titanium catalyst does not need to undergo complicated pre-treatment before use, which can simplify the process.

[0023] Chelated titanium catalyst refers to a chelate formed by the coordination of titanium ions and chelating agents. In some embodiments, the chelated titanium catalyst can be selected from at least one of the group consisting of phosphate titanate chelate, citrate titanium chelate and hydroxy acid ester titanate chelate. Phosphate titanate chelate is obtained by chelating butyl titanate with diethyl phosphate, dibutyl phosphate or monobutyl phosphate. Citrate titanium chelate can be, for example, Borica's TYTANTM AQ5000. Hydroxy acid ester titanate chelate is obtained by chelating butyl titanate with hydroxy acid ester, for example, Borica's TYTANTM AQ5860.

[0024] In some embodiments, the product obtained from the depolymerization reaction also includes oligomers.

[0025] In some embodiments, the depolymerization liquid accounts for 30 wt % to 80 wt % of the total weight of the reactants in the depolymerization reaction, preferably 40 wt % to 70 wt %, but the present invention is not limited thereto.

[0026] In some embodiments, the amount of the depolymerization catalyst added is 0.3 wt% to 8 wt% of the total weight of the reactants of the depolymerization reaction, preferably 1.0 wt% to 5.0 wt%, but the present invention is not limited thereto. In some embodiments, the amount of titanium added to the depolymerization catalyst is 10 ppm to 200 ppm of the total weight of the reactants of the depolymerization reaction, preferably 50 ppm to 150 ppm.

[0027] In some embodiments, the depolymerization reaction time is between 1 hour and 6 hours, preferably between 3 hours and 5 hours, but the present invention is not limited thereto.

[0028] Then, the product obtained from the depolymerization reaction is subjected to a transesterification reaction. For example, the product obtained from the depolymerization reaction is subjected to a transesterification reaction with an aliphatic diol to convert ethylene terephthalate into bis-hydroxypropyl terephthalate (BHPT) or bis-hydroxybutylterephthalate (BHBT).

[0029] The transesterification reaction can be carried out in an environment containing a transesterification catalyst to increase the reaction rate, wherein the transesterification catalyst can include a chelated titanium catalyst. The materials of the chelated titanium catalyst can refer to the above-mentioned materials for the depolymerization catalyst, which will not be repeated here. Since the chelated titanium catalyst has high activity, is not easy to deactivate, and can be evenly dispersed in the aliphatic diol, a small amount of catalyst can be used to effectively catalyze the transesterification reaction. In addition, the chelated titanium catalyst does not need to undergo complicated pre-treatment before use, which can simplify the process.

[0030] In some embodiments, the transesterification catalyst may be the same as or different from the depolymerization catalyst, but the present invention is not limited thereto.

[0031] In some embodiments, the aliphatic diol is selected from at least one of the group consisting of C3 to C10 diols. In some embodiments, the aliphatic diol may include 1,2-propylene glycol, 1,2-propanediol, 1,4-butanediol or other suitable aliphatic diols.

[0032] In some embodiments, in the transesterification reaction, the molar ratio of ethylene terephthalate to aliphatic diol is between 1:1 and 1:5.

[0033] In some embodiments, the reaction temperature of the transesterification reaction is between 210°C and 260°C, and the reaction pressure is between normal pressure and 3.5 kg / cm 2 between.

[0034] In some embodiments, the transesterification reaction time is between 1 hour and 6 hours, preferably between 3 hours and 5 hours, but the present invention is not limited thereto.

[0035] In some embodiments, the esterification rate of the transesterification reaction is between 90% and 99.5%.

[0036] Afterwards, the product obtained from the transesterification reaction is polymerized with a long-chain polyalkylene glycol to obtain a thermoplastic polyester elastomer. The obtained thermoplastic polyester elastomer includes a soft segment and a hard segment, wherein the soft segment is mainly composed of a long-chain polyalkylene glycol, and the hard segment is mainly composed of polybutylene terephthalate (PBT) obtained by polycondensation of BHBT. In some other embodiments, the hard segment of the thermoplastic polyester elastomer is mainly composed of polypropylene terephthalate (PPT) obtained by polycondensation of BHPT.

[0037] The polymerization reaction can be carried out in an environment containing a polymerization catalyst to increase the reaction rate, wherein the polymerization catalyst can include a chelated titanium catalyst. The materials of the chelated titanium catalyst can refer to the materials of the above-mentioned depolymerization catalyst, which will not be repeated here. Since the chelated titanium catalyst has high activity, is not easy to deactivate, and can be evenly dispersed in the reactants, a small amount of catalyst can be used to effectively catalyze the polymerization reaction. In addition, the chelated titanium catalyst does not need to undergo complicated pre-treatment before use, which can simplify the process.

[0038] In some embodiments, the polymerization catalyst may be the same as or different from the depolymerization catalyst and / or the transesterification catalyst, but the present invention is not limited thereto.

[0039] In some embodiments, an auxiliary catalyst may be added to the polymerization reaction to enhance the activity of the catalyst. The auxiliary catalyst may include, for example, sodium acetate or other suitable auxiliary catalysts.

[0040] In some embodiments, the long-chain polyalkylene glycol includes polyethylene glycol (PEG) or polytetramethylene ether glycol (PTMEG).

[0041] In some embodiments, the amount of the long-chain polyalkylene glycol added in the polymerization reaction accounts for 20 wt % to 60 wt % of the total weight of the reactants in the polymerization reaction.

[0042] In some embodiments, the polymerization reaction is performed under vacuum, that is, the reaction pressure is about 0.5 Torr or less. In some embodiments, the reaction temperature of the polymerization reaction is between 200°C and 300°C.

[0043] In some embodiments, the polymerization reaction time is between 1 hour and 3 hours, preferably between 1 hour and 2 hours, so that the thermoplastic polyester elastomer reaches a target intrinsic viscosity, such as 0.6 to 2.0 dL / g, but the present invention is not limited thereto.

[0044] In some embodiments, an antioxidant may be added during the polymerization reaction to prevent the resulting thermoplastic polyester elastomer from being degraded due to oxidation. The antioxidant may be at least one selected from the group consisting of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropionate, tris(2,4-di-tert-butyl)phenyl phosphite, and n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0045] In some embodiments, before the polymerization reaction, a prepolymerization may be performed, which includes heating the reactants to 200° C. to 300° C. and reducing the pressure from normal pressure to 20 Torr within 1 hour.

[0046] Then, the thermoplastic polyester elastomer obtained by polymerization can be granulated by a single-screw granulator or a twin-screw granulator to form thermoplastic polyester elastomer pellets, so as to facilitate subsequent applications.

[0047] In some embodiments, the thermoplastic polyester elastomer prepared by the manufacturing method of this embodiment has good hue quality, for example, the L value is above 60, the a value is between -3 and +3, and the b value is below 3, but the present invention is not limited thereto. The above L value, a value, and b value refer to the CIE Lab color space commonly used in the industry, where the L value indicates brightness, the a value indicates green-red value, and the b value indicates blue-yellow value.

[0048] In the manufacturing method of the present embodiment, since the depolymerization catalyst, transesterification catalyst and polymerization catalyst are all chelated titanium catalysts, the catalytic effect can be achieved while using a smaller amount of catalyst, thereby reducing the overall manufacturing cost; or, from another perspective, while using the same amount of catalyst, the manufacturing method of the present embodiment can efficiently (for example, in a shorter time) obtain a thermoplastic polyester elastomer with desired properties (for example, viscosity, color quality, etc.).

[0049] The following experimental examples are used to explain the method for producing the thermoplastic polyester elastomer of the present invention in detail. However, the following experimental examples are not intended to limit the present invention.

[0050] Example 1

[0051] 3840 g of recycled PET bottle flakes were subjected to a depolymerization reaction with 1837 g of ethylene glycol and 8.29 g of titanium citrate chelate (containing 100 ppm of titanium) (as a depolymerization catalyst and a transesterification catalyst) (purchased from Borica TYTAN AQ5000), wherein the depolymerization temperature was about 230° C. and the depolymerization pressure was about 0.8 kg / cm when the bottle flakes were not completely dissolved. 2 , after the bottle pieces are completely dissolved, adjust to about 3.0kg / cm 2 , and the reaction continued for 2 hours.

[0052] Then, 6470 g of 1,4-butanediol was added to the product obtained after the depolymerization reaction to perform a transesterification reaction, wherein the temperature of the transesterification reaction was about 245° C. and the pressure was 0.2 kg / cm 2 The reaction was carried out for 3 hours under nitrogen purge to obtain BHBT ester.

[0053] The obtained BHBT ester was decompressed and transferred to a polymerization tank. Then, 1,248 g PTMEG1000 (purchased from Formosa Plastics FAS PTMG, molecular weight: 1000), 1,248 g PTMEG2000 (purchased from Formosa Plastics FAS PTMG, molecular weight: 2000), 1,664 g PTMEG3000 (purchased from Formosa Plastics FAS PTMG, molecular weight: 3000), 8 g antioxidant (pentaerythritol tetrakis (3,5-di-tert-butyl-4-hydroxy) phenylpropionate, purchased from BASF 1010), 2g of sodium acetate (auxiliary catalyst) (made from Air Water Performance Chemical) and 50ppm of titanium added titanium chelate (polymerization catalyst) (purchased from Borica TYTAN AQ5000) were mixed with the BHBT ester.

[0054] After that, prepolymerization is performed, and the pressure is gradually reduced from normal pressure to 20 Torr within 1 hour, and the target material temperature is 250° C. Then, the main polymerization reaction is performed, and the vacuum is fully opened, and the pressure is reduced from 20 Torr to 0.5 Torr, and the material temperature is about 250° C. to 260° C. The reaction time is about 1 hour to 2 hours, and the product reaches a viscosity of about 1.4 dL / g to 1.6 dL / g to obtain a thermoplastic polyester elastomer.

[0055] Example 2

[0056] The process of Example 2 is similar to that of Example 1, except that the polymerization catalyst used in Example 2 is hydroxy acid ester titanate chelate (purchased from Borica TYTAN AQ5860).

[0057] Example 3

[0058] Example 3 is similar to the process of Example 1, except that the polymerization catalyst used in Example 3 is a phosphate titanate chelate. The phosphate titanate chelate is prepared from butyl titanate (purchased from Borica TYTAN TNBT) and monobutyl phosphate (purchased from Chengbei Chemical JAMP-4P). In the polymerization reaction, the ratio of titanium addition to phosphorus addition is 5:2.

[0059] Comparative Example 1

[0060] The process of Comparative Example 1 is similar to that of Example 1, except that the polymerization catalyst used in Comparative Example 1 is titanium butoxide (purchased from Borica TYTAN TNBT).

[0061] Comparative Example 2

[0062] The process of Comparative Example 2 is similar to that of Example 1, except that the polymerization catalyst used in Comparative Example 2 is titanium isopropoxide (purchased from Borica TYTAN TIPT).

[0063] The main polymerization time, viscosity and hue quality (wherein the hue quality is represented by L, a, b) of Examples 1 to 3 and Comparative Examples 1 to 2 are recorded in Table 1.

[0064] Table 1

[0065]

[0066] As shown in Table 1, under the same process conditions, the thermoplastic polyester elastomers produced in Examples 1 to 3 using the chelated titanium catalyst as the polymerization catalyst can achieve the thermoplastic polyester elastomers that meet the viscosity and color requirements in a shorter time compared to Comparative Example 1 (using butyl titanate as the polymerization catalyst) and Comparative Example 2 (using isopropyl titanate as the polymerization catalyst). In addition, due to the property that the chelated titanium catalyst is not easily deactivated, no additional catalyst is required in the transesterification reaction of Examples 1 to 3, which can reduce the amount of catalyst used.

[0067] In summary, the manufacturing method of the thermoplastic polyester elastomer of the present invention is to obtain the thermoplastic polyester elastomer by subjecting the polyester recyclate to depolymerization reaction, transesterification reaction and polymerization reaction, which can effectively recycle the waste PET and reduce the environmental burden, so as to achieve the goals of environmental protection and circular economy. In addition, the catalysts used in the depolymerization reaction, transesterification reaction and polymerization reaction each include a chelated titanium catalyst, so that the reaction rate can be increased, the catalytic effect is good, and the overall manufacturing cost is reduced.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing a thermoplastic polyester elastomer, characterized in that: include: Providing a polyester recyclate, the polyester recyclate comprising polyethylene terephthalate; carrying out a depolymerization reaction of the polyester recycled material and ethylene glycol; performing a transesterification reaction on the product obtained from the depolymerization reaction and an aliphatic diol; and The product obtained by the transesterification reaction is polymerized with a long-chain polyalkylene glycol to obtain a thermoplastic polyester elastomer. The catalysts used in the depolymerization reaction, the transesterification reaction and the polymerization reaction each include a chelated titanium catalyst.

2. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The chelated titanium catalyst is at least one selected from the group consisting of phosphate titanate chelate, citrate titanium chelate and hydroxy acid ester titanate chelate.

3. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The catalyst used in the depolymerization reaction, the catalyst used in the transesterification reaction and the catalyst used in the polymerization reaction are all the same.

4. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The long-chain polyalkylene glycol includes polyethylene glycol or polytetramethylene ether glycol.

5. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The aliphatic diol is at least one selected from the group consisting of C3 to C10 diols.

6. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The product obtained from the transesterification reaction includes dihydroxypropyl terephthalate and / or dihydroxybutyl terephthalate.

7. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The amount of the long-chain polyalkylene glycol added in the polymerization reaction accounts for 20 wt % to 60 wt % of the total weight of the reactants in the polymerization reaction.

8. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The polymerization reaction is carried out under a vacuum environment.

9. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: The reaction temperature of the polymerization reaction is between 200 and 300 degrees.

10. The method for producing a thermoplastic polyester elastomer according to claim 1, characterized in that: It also includes adding an antioxidant to the polymerization reaction.

Images