Manufacturing method of thermoplastic polyester elastomer

Abstract

To provide a method for effectively recovering and utilizing polyester waste.SOLUTION: A method for preparing a thermoplastic polyester elastomer comprises: providing a polyester recyclate comprising polyethylene terephthalate (PET); subjecting the polyester recyclate to a depolymerization reaction with ethylene glycol; subjecting the product obtained by the depolymerization reaction to a transesterification reaction with an aliphatic diol; and subjecting the product obtained by the transesterification reaction to a polymerization reaction with a long-chain poly (alkyldiol) to obtain the thermoplastic polyester elastomer. The catalysts used in the depolymerization reaction, the transesterification reaction, and the polymerization reaction each include a chelate-type titanium catalyst.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a thermoplastic polyester elastomer. [Background technology]

[0002] Polyester products such as textiles (e.g. clothing), PET bottles, and plastic bags are widely used in our daily lives, which generates a lot of polyester waste. How to effectively recover and utilize this polyester waste is an important issue. Summary of the Invention

[0003] The present invention provides a method for producing a thermoplastic polyester elastomer, which can effectively recover and reuse discarded polyester products and reduce production costs.

[0004] The method for producing a thermoplastic polyester elastomer of the present invention includes the steps of providing a polyester recycle containing polyethylene terephthalate, depolymerizing the polyester recycle with ethylene glycol, transesterifying the product obtained by the depolymerization with an aliphatic diol, and polymerizing the product obtained by the transesterification with a long-chain poly(alkyl diol) to obtain a thermoplastic polyester elastomer. The catalysts used in the depolymerization, transesterification, and polymerization reactions each contain a chelate-type titanium catalyst.

[0005] In one embodiment of the present invention, the above-mentioned chelate-type titanium catalyst is selected from at least one of the group consisting of phosphate titanate ester chelate, citrate titanium chelate, and hydroxy acid ester titanate ester chelate.

[0006] In one embodiment of the present invention, the catalyst used in the depolymerization reaction, the catalyst used in the ester exchange reaction, and the catalyst used in the polymerization reaction are all the same.

[0007] In one embodiment of the present invention, the long chain poly(alkyl diol) comprises polyethylene glycol or polytetramethylene ether glycol.

[0008] In one embodiment of the present invention, the above-mentioned aliphatic diol is selected from at least one of the group consisting of diols having 3 to 10 carbon atoms.

[0009] In one embodiment of the present invention, the product obtained from the above-mentioned transesterification reaction comprises bis-hydroxypropyl terephthalate and / or bis-hydroxybutyl terephthalate.

[0010] In one embodiment of the present invention, the amount of the long chain poly(alkyl diol) added during the polymerization reaction accounts for 20% to 60% by weight of the total weight of the reactants of the polymerization reaction.

[0011] In one embodiment of the present invention, the above-mentioned polymerization reaction is carried out in a vacuum environment.

[0012] In one embodiment of the present invention, the reaction temperature of the above-mentioned polymerization reaction is between 200°C and 300°C.

[0013] In one embodiment of the present invention, the above-mentioned method further comprises adding an antioxidant during the polymerization reaction.

[0014] Based on the above, the method for producing a thermoplastic polyester elastomer of the present invention is to produce a thermoplastic polyester elastomer by subjecting recycled polyester to depolymerization, transesterification, and polymerization, and can effectively recover and reuse discarded polyethylene terephthalate (PET) to reduce the environmental load, thereby achieving the effects of environmental protection and recycling economy. In addition, the catalysts used in the depolymerization, transesterification, and polymerization reactions each contain a chelate-type titanium catalyst, so that a good catalytic effect can be achieved using a relatively small amount of catalyst, and the overall production cost can be reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0016] In the present invention, a range expressed as "one value to another value" is a summary expression that avoids listing all values ​​within the range in the specification. Thus, the description of a particular numerical range covers any numerical value within that numerical range and any smaller numerical range defined by any value within that numerical range, as if such any numerical value and smaller numerical range were described in the specification.

[0017] The following is a description of the implementation of the present invention through certain specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed herein. The present invention can also be implemented or applied through other different specific embodiments, and each detail of the present specification can be modified and changed based on different perspectives and applications without departing from the concept of the present invention. The following embodiments further describe the technical contents related to the present invention in detail, but the disclosed contents are not used to limit the protection scope of the present invention. Furthermore, the term "or" used in this specification can include any one or more combinations of the relevant listed items according to the actual situation.

[0018] Hereinafter, a method for producing a thermoplastic polyester elastomer according to one embodiment of the present invention will be described in detail.

[0019] First, a polyester reclaimed material is provided that includes polyethylene terephthalate (PET). By way of example, the polyester reclaimed material may be polyester fabric, plastic bottle flakes, or the like. In some embodiments, the polyester reclaimed material further includes dyes or other impurities.

[0020] In some embodiments, the polyester regenerated material may be pretreated to remove impurities, and the pretreatment may be other suitable procedures, such as a decolorization treatment. The decolorization treatment may be achieved, for example, by immersing the polyester regenerated material in an extraction solvent by extraction to extract impurities, but the present invention is not limited thereto as long as the impurities of the polyester regenerated material 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 monomethyl ether, and ethylene glycol.

[0021] Then, the polyester regenerated material is subjected to a depolymerization reaction. For example, ethylene glycol may be used as a depolymerization liquid, and the polyester regenerated material may be depolymerized with ethylene glycol to obtain a product containing bis(2-hydroxyethyl terephthalate) (BHET).

[0022] The depolymerization reaction may be carried out in an environment containing a depolymerization catalyst to increase the reaction rate, and the depolymerization catalyst may contain a chelate-type titanium catalyst. The chelate-type titanium catalyst is highly active, is not easily deactivated, and can be uniformly dispersed in the depolymerization liquid, so that a small amount of catalyst can effectively catalyze the depolymerization reaction. In addition, no complicated pretreatment is required before use of the chelate-type titanium catalyst, and the production process can be simplified.

[0023] The chelate-type titanium catalyst refers to a chelate formed by coordinating titanium ions with a chelating agent. In some embodiments, the chelate-type titanium catalyst may be selected from at least one of the group consisting of a phosphate titanate chelate, a citrate titanium chelate, and a hydroxy acid ester titanate chelate. The phosphate titanate chelate is obtained, for example, by the chelation reaction of butyl titanate with diethyl phosphate, dibutyl phosphate, or monobutyl phosphate. The citrate titanium chelate is, for example, TYTANTM AQ5000 from Borica. The hydroxy acid ester titanate chelate is, for example, by the chelation reaction of butyl titanate with a hydroxy acid ester, and may be, for example, TYTANTM AQ5860 from Borica.

[0024] In some embodiments, the product obtained from the depolymerization reaction further comprises oligomers.

[0025] In some embodiments, the depolymerization liquid accounts for 30 wt% to 80 wt% of the total weight of the reactants of the depolymerization reaction, and preferably 40 wt% to 70 wt%, although 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%, preferably 1.0 wt% to 5.0 wt%, of the total weight of the reactants in the depolymerization reaction, but the present invention is not limited thereto. In some embodiments, the amount of titanium added in the depolymerization catalyst accounts for 10 ppm to 200 ppm, preferably 50 ppm to 150 ppm, of the total weight of the reactants in the depolymerization reaction.

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

[0028] The depolymerization product is then transesterified, for example, by transesterifying the depolymerization product with an aliphatic diol to convert polyethylene terephthalate to bis-hydroxypropyl terephthalate (BHPT) or bis-hydroxybutyl terephthalate (BHBT).

[0029] The transesterification reaction may be carried out in an environment containing a transesterification catalyst to increase the reaction rate, and the transesterification catalyst may contain a chelate-type titanium catalyst. The material of the chelate-type titanium catalyst can be referred to the material related to the depolymerization catalyst described above, and will not be described here repeatedly. The chelate-type titanium catalyst is highly active, difficult to be deactivated, and can be uniformly dispersed in the aliphatic diol, so that a small amount of catalyst can effectively catalyze the transesterification reaction. In addition, no complicated pretreatment is required before using the chelate-type titanium catalyst, and the production process can be simplified.

[0030] In some embodiments, the transesterification catalyst may be the same as or different from the depolymerization catalyst, and the invention is not limited in this respect.

[0031] In some embodiments, the aliphatic diol is selected from at least one of the group consisting of diols having from 3 to 10 carbon atoms. In some embodiments, the aliphatic diol may include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, or other suitable aliphatic diol.

[0032] In some embodiments, the molar ratio of polyethylene terephthalate to aliphatic diol during the transesterification reaction 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 It is between.

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

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

[0036] The product of the transesterification is then polymerized with a long-chain poly(alkyl diol) to obtain a thermoplastic polyester elastomer. The resulting thermoplastic polyester elastomer contains soft and hard segments, the soft segments being primarily composed of the long-chain poly(alkyl diol) and the hard segments being primarily composed of polybutylene terephthalate (PBT) obtained by condensation polymerization of BHBT. In some embodiments, the hard segments of the thermoplastic polyester elastomer are primarily composed of polypropylene terephthalate (PPT) obtained by condensation polymerization of BHPT.

[0037] The polymerization reaction may be carried out in an environment containing a polymerization catalyst to increase the reaction rate, and the polymerization catalyst may include a chelate-type titanium catalyst. The material of the chelate-type titanium catalyst may refer to the material related to the depolymerization catalyst described above, and will not be described again here. The chelate-type titanium catalyst is highly active, difficult to be deactivated, and can be uniformly dispersed in the reactants, so that a small amount of catalyst can effectively catalyze the polymerization reaction. In addition, no complicated pretreatment is required before using the chelate-type titanium catalyst, and the manufacturing process can be simplified.

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

[0039] In some embodiments, a co-catalyst may be added during the polymerization reaction to increase the activity of the catalyst. The co-catalyst may include, for example, sodium acetate or other suitable co-catalyst.

[0040] In some embodiments, the long chain poly(alkyl diol) comprises polyethylene glycol (PEG) or polytetramethylene ether glycol (PTMEG).

[0041] In some embodiments, the amount of long chain poly(alkyl diol) added during the polymerization reaction comprises 20% to 60% by weight of the total weight of the polymerization reactants.

[0042] In some embodiments, the polymerization reaction is carried out in a vacuum environment, i.e., 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, which allows the thermoplastic polyester elastomer to achieve a target intrinsic viscosity, for example, 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 oxidative degradation. The antioxidant may be selected from at least one of the group consisting of pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], tris(2,4-di-tert-butylphenyl)phosphite, and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0045] In some embodiments, the polymerization reaction may be preceded by a prepolymerization, which involves heating the reactants to 200° C.-300° C. and reducing the pressure from ambient to 20 Torr within 1 hour.

[0046] The thermoplastic polyester elastomer obtained by polymerization may then be granulated by a single screw granulator or a twin screw granulator to form thermoplastic polyester elastomer granules for easy subsequent application.

[0047] In some embodiments, the thermoplastic polyester elastomer produced by the production method of the present embodiment has good hue quality, for example, an L value of 60 or more, an a value between -3 and +3, and a value of 3 or less, but the present invention is not limited thereto. The above-mentioned L value, a value, and b value refer to the CIE Lab color space commonly used in the industry, where the L value represents luminance, the a value represents green and red values, and the b value represents blue and yellow values.

[0048] In the production method of this embodiment, since the depolymerization catalyst, the ester exchange catalyst, and the polymerization catalyst are all chelate-type titanium catalysts, the catalytic effect can be achieved using a relatively small amount of catalyst, and the overall production cost can be reduced. Alternatively, from another perspective, when the same amount of catalyst is used, the production method of this embodiment can efficiently (for example, in a shorter time) obtain a thermoplastic polyester elastomer having required properties (for example, viscosity, color quality, etc.).

[0049] The method for producing the thermoplastic polyester elastomer of the present invention will be described in detail below with reference to experimental examples, although the present invention is not limited to these experimental examples.

[0050] Example 1

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

[0052] Thereafter, 6470 g of 1,4-butanediol was added to the product obtained after depolymerization to carry out an ester exchange reaction, of which the ester exchange reaction temperature was about 425°C and the flow rate was 0.2 kg / cm 2 The reaction was carried out for 3 hours under a pressure of 1000 MPa and a nitrogen purge to obtain a BHBT ester compound.

[0053] The obtained BHBT ester compound was transferred to a polymerization tank after reducing the pressure. Then, 1248 g of PTMEG1000 (FAS PTMG, 1000 molecular weight, purchased from Formosa Asahi), 1248 g of PTMEG2000 (FAS PTMG, 2000 molecular weight, purchased from Formosa Asahi), 1664 g of PTMEG3000 (FAS PTMG, 3000 molecular weight, purchased from Formosa Asahi), 8 g of antioxidant (pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate], Irganox® 1010, purchased from BASF), 2 g of sodium acetate (cocatalyst, purchased from Air Water Performance Chemicals), and titanium citrate chelate (polymerization catalyst) with 50 ppm titanium loading (TYTAN AQ5000, purchased from Borica) were mixed with the BHBT ester compound.

[0054] Then, preliminary polymerization was carried out, the pressure was reduced from normal pressure to 20 Torr within 1 hour, and the target material temperature was set to 250°C. Then, the main polymerization reaction was carried out, the vacuum was fully opened, the pressure was reduced from 20 Torr to 0.5 Torr, the material temperature was set to 250°C-260°C, the reaction time was about 1-2 hours, and the product reached a viscosity of about 1.4dL / g-1.6dL / g, thus obtaining a thermoplastic polyester elastomer.

[0055] Example 2

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

[0057] Example 3

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

[0059] Comparative Example 1

[0060] Comparative Example 1 was prepared in a similar manner to that of Example 1, and the polymerization catalyst used in Comparative Example 1 was butyl titanate (TYTAN TNBT, purchased from Borica).

[0061] Comparative Example 2

[0062] Comparative Example 2 is similar to the preparation method of Example 1, and the polymerization catalyst used in Comparative Example 2 is isopropyl titanate (TYTAN TIPT, purchased from Borica).

[0063] Table 1 shows the main polymerization time, viscosity and color quality of the obtained products (color quality is represented by L, a, b) in Examples 1 to 3 and Comparative Examples 1 and 2.

[0064] [Table 1]

[0065] As can be seen from Table 1, under the same production conditions, the thermoplastic polyester elastomers produced in Examples 1 to 3 using a chelate-type titanium catalyst as a polymerization catalyst can reach a thermoplastic polyester elastomer that meets the viscosity and color requirements in a shorter time than Comparative Example 1 (using butyl titanate as a polymerization catalyst) and Comparative Example 2 (using isopropyl titanate as a polymerization catalyst). In addition, since the chelate-type titanium catalyst is difficult to deactivate, there is no need to add a separate catalyst in the transesterification reaction of Examples 1 to 3, and the amount of catalyst used can be reduced.

[0066] In summary, the method for producing a thermoplastic polyester elastomer of the present invention is to produce a thermoplastic polyester elastomer by subjecting recycled polyester to depolymerization, transesterification, and polymerization, and effectively recover and reuse discarded PET to reduce the environmental load, thereby achieving the goals of environmental protection and circular economy. In addition, the catalysts used in the depolymerization, transesterification, and polymerization reactions each contain a chelate-type titanium catalyst, which can increase the reaction rate and have good catalytic effect to reduce the overall production cost.

[0067] Although the present invention has been disclosed in the above embodiments, they are not used to limit the present invention, and a person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, and therefore the protection scope of the present invention should be as defined by the appended claims.

Claims

1. Providing a polyester reclaimed product comprising polyethylene terephthalate; subjecting the polyester regenerated product to a depolymerization reaction with ethylene glycol; subjecting the product obtained by the depolymerization reaction to a transesterification reaction with an aliphatic diol; the product obtained by the transesterification reaction is polymerized with a long-chain poly(alkyl diol) to obtain a thermoplastic polyester elastomer; Including, The catalysts used in the depolymerization reaction, the ester exchange reaction, and the polymerization reaction each contain a chelate-type titanium catalyst. A method for producing a thermoplastic polyester elastomer.

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

3. The method for producing a thermoplastic polyester elastomer according to claim 1 , wherein the catalyst used in the depolymerization reaction, the catalyst used in the ester exchange 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 , wherein the long chain poly(alkyl diol) comprises polyethylene glycol or polytetramethylene ether glycol.

5. The method for producing a thermoplastic polyester elastomer according to claim 1, wherein the aliphatic diol is selected from at least one of the group consisting of diols having 3 to 10 carbon atoms.

6. The method for producing a thermoplastic polyester elastomer according to claim 1, wherein the product obtained by the transesterification reaction comprises bis-hydroxypropyl terephthalate and / or bis-hydroxybutyl terephthalate.

7. 2. The method of claim 1, wherein the amount of the long chain poly(alkyl diol) added during the polymerization reaction accounts for 20% to 60% by weight of the total weight of the reactants of the polymerization reaction.

8. The method for producing a thermoplastic polyester elastomer according to claim 1 , wherein the polymerization reaction is carried out in a vacuum environment.

9. The method for producing a thermoplastic polyester elastomer according to claim 1, wherein the reaction temperature of the polymerization reaction is between 200°C and 300°C.

10. The method for producing the thermoplastic polyester elastomer according to claim 1, further comprising adding an antioxidant during the polymerization reaction.

Images