Method for producing a 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 Art

[0002] Polyester products such as fabrics (e.g., clothing), PET bottles, and plastic bags are widely used in daily life, and for this reason, a large amount of polyester waste is generated. How to effectively recover and utilize these polyester wastes is an important issue.

Summary of the Invention

[0003] The present invention provides a method for producing a thermoplastic polyester elastomer that can effectively recover and reuse waste polyester products to reduce manufacturing costs.

[0004] The method for producing a thermoplastic polyester elastomer of the present invention includes providing a polyester recycled material containing polyethylene terephthalate, subjecting the polyester recycled material 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(alkyl diol) to obtain a thermoplastic polyester elastomer. The catalysts used in the depolymerization reaction, transesterification reaction, and polymerization reaction 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 phosphoric acid ester titanic acid ester chelate, citric acid titanium chelate, and hydroxy acid ester titanic acid ester chelate.

[0006] In one embodiment of the present invention, the catalysts used in the above-mentioned depolymerization reaction, transesterification reaction, and polymerization reaction are all the same.

[0007] In one embodiment of the present invention, the above-mentioned long-chain poly(alkyl diol) includes 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 by the above-mentioned transesterification reaction includes bis-hydroxypropyl terephthalate and / or bis-hydroxybutyl terephthalate.

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

[0011] In one embodiment of the present invention, the above-mentioned polymerization reaction is carried out under 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 manufacturing method further includes adding an antioxidant during the polymerization reaction.

[0014] Based on the above, the manufacturing method of the thermoplastic polyester elastomer of the present invention manufactures a thermoplastic polyester elastomer by subjecting polyester recycled materials to a depolymerization reaction, a transesterification reaction, and a polymerization reaction, effectively recovering and recycling the discarded polyethylene terephthalate (PET) to reduce the environmental load, and thus achieving the effects of environmental protection and circular economy. In addition, the catalysts used in the depolymerization reaction, the transesterification reaction, and the polymerization reaction each contain a chelate-type titanium catalyst. Therefore, a good catalytic effect can be achieved using a relatively small amount of catalyst, and the overall manufacturing cost can be reduced.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are 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. Therefore, the description of a specific numerical range covers any numerical value within the range and a smaller value range defined by any value within the range, as if any numerical value and a smaller numerical range were described in the specification.

[0017] The following is an explanation of the implementation method of the present invention according to specific specific embodiments, and those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and each detail in this specification can also be modified and changed based on different perspectives and applications without departing from the concept of the present invention. The following embodiments further explain the technical content related to the present invention, but the disclosed content is not used to limit the protection scope of the present invention. Furthermore, the term "or" used in this specification can include any one or a combination of multiple of the related 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, provide a polyester recycled material containing polyethylene terephthalate (PET). By way of example, the polyester recycled material may be a polyester fabric, PET bottle flakes, or the like. In some embodiments, the polyester recycled material further contains dyes or other impurities.

[0020] In some embodiments, impurities may be removed by performing pretreatment on the recycled polyester. The pretreatment may be other appropriate procedures such as, for example, a decolorization treatment. The decolorization treatment may achieve the effect of decolorization by immersing the recycled polyester in an extraction solvent by an extraction method to extract impurities, but the present invention is not limited thereto, and it is sufficient if the impurities of the recycled polyester 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] Thereafter, a depolymerization reaction is performed on the recycled polyester. For example, ethylene glycol may be used as the depolymerization solution, and the recycled polyester may be subjected to a depolymerization reaction 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. Among them, the depolymerization catalyst may include a chelate-type titanium catalyst. The chelate-type titanium catalyst has high activity, is difficult to deactivate, and can be uniformly dispersed in the depolymerization solution, so that the depolymerization reaction can be effectively catalyzed with a small amount of catalyst. In addition, complicated pretreatment is not required before using the chelate-type titanium catalyst, and the manufacturing process can be simplified.

[0023] The chelate-type titanium catalyst refers to a chelate formed by the coordination of 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 phosphate ester titanate chelate, citric acid titanium chelate, and hydroxy acid ester titanate chelate. The phosphate ester titanate chelate can be obtained, for example, by the chelation reaction of butyl titanate with diethyl phosphate, dibutyl phosphate, or monobutyl phosphate. The citric acid titanium chelate is, for example, TYTANTM AQ5000 from Borica. The hydroxy acid ester titanate chelate can be obtained, 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 in the depolymerization reaction further contains oligomers.

[0025] In some embodiments, the depolymerization solution 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 addition amount of the depolymerization catalyst is 0.3 wt% to 8 wt% of the total weight of the reactants in the depolymerization reaction, preferably 1.0 wt% to 5.0 wt%, but the present invention is not limited thereto. In some embodiments, the titanium addition amount of the depolymerization catalyst accounts for 10 ppm to 200 ppm of the total weight of the reactants in the depolymerization reaction, preferably 50 ppm to 150 ppm.

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

[0028] Thereafter, a transesterification reaction is performed on the product obtained from the depolymerization reaction. For example, by subjecting the product obtained from the depolymerization reaction to a transesterification reaction with an aliphatic diol, polyethylene terephthalate is converted into 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 among them, the transesterification catalyst may contain a chelate-type titanium catalyst. The material of the chelate-type titanium catalyst can refer to the materials related to the above-mentioned depolymerization catalyst, and will not be repeatedly described here. The chelate-type titanium catalyst has high activity, is difficult to deactivate, and can be uniformly dispersed in the aliphatic diol, so it can effectively catalyze the transesterification reaction with a small amount of catalyst. In addition, complicated pretreatment is not required before using the chelate-type titanium catalyst, and the manufacturing process can be simplified.

[0030] In some embodiments, the transesterification catalyst may be the same as or different from the depolymerization catalyst, and the present invention does not limit this.

[0031] In some embodiments, the aliphatic diol is selected from at least one of the group consisting of diols having 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 diols.

[0032] In some embodiments, during the transesterification reaction, the molar ratio of polyethylene terephthalate to the 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 time of the transesterification reaction 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 90% - 99.5%.

[0036] Thereafter, the product obtained from the transesterification reaction is polymerized with a long-chain poly(alkyl diol) to obtain a thermoplastic polyester elastomer. The obtained thermoplastic polyester elastomer contains a soft segment and a hard segment. Among them, the soft segment is mainly composed of a long-chain poly(alkyl diol), and the hard segment is mainly composed of polybutylene terephthalate (PBT) obtained by polycondensing BHBT. In some embodiments, the hard segment of the thermoplastic polyester elastomer is mainly composed of polypropylene terephthalate (PPT) obtained by polycondensing BHPT.

[0037] The polymerization reaction may be carried out in an environment containing a polymerization catalyst to increase the reaction rate. Among them, the polymerization catalyst may include a chelate-type titanium catalyst. The material of the chelate-type titanium catalyst can refer to the materials related to the depolymerization catalyst described above, and will not be repeated here. The chelate-type titanium catalyst has high activity, is difficult to deactivate, and can be uniformly dispersed in the reactants, so it can effectively catalyze the polymerization reaction with a small amount of catalyst. In addition, complicated pretreatment is not required before the use of 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 present invention does not limit this.

[0039] In some embodiments, an auxiliary catalyst may be added during the polymerization reaction to increase 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 poly(alkyl diol) includes polyethylene glycol (PEG) or polytetramethylene ether glycol (PTMEG).

[0041] In some embodiments, the addition amount during the polymerization reaction of the long-chain poly(alkyl diol) 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 carried out under a vacuum environment, 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, thereby achieving a target intrinsic viscosity, such as 0.6 to 2.0 dL / g, for the thermoplastic polyester elastomer, but the present invention is not limited thereto.

[0044] In some embodiments, by adding an antioxidant during the polymerization reaction, it may be possible to avoid the thermoplastic polyester elastomer obtained from deteriorating due to oxidation. 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, prepolymerization may be carried out first before the polymerization reaction, including heating the reactants to 200 °C to 300 °C and reducing the pressure from normal pressure to 20 Torr within 1 hour.

[0046] Thereafter, in order to facilitate subsequent applications, granulation may be performed on the thermoplastic polyester elastomer obtained by polymerization using a single-screw granulator or a twin-screw granulator to form thermoplastic polyester elastic granules.

[0047] In some embodiments, the thermoplastic polyester elastomer produced by the production method of this embodiment has good hue quality such as, for example, an L value of 60 or more, an a value between -3 and +3, and a b 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. The L value represents luminance, the a value represents the value of green and red, and the b value represents the value of blue and yellow.

[0048] In the production method of this embodiment, since the depolymerization catalyst, the transesterification 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. Or, from another perspective, when using the same amount of catalyst, the production method of this embodiment can efficiently (for example, in a shorter time) obtain a thermoplastic polyester elastomer having the required properties (such as viscosity, hue quality, etc.).

[0049] Hereinafter, the production method of the thermoplastic polyester elastomer of the present invention described above will be described in detail with experimental examples. However, the following experimental examples do not limit the present invention.

[0050] Example 1

[0051] 3840 g of recycled PET bottle flakes and 1837 g of ethylene glycol were subjected to a polymerization reaction with 8.29 g of titanium citrate chelate (containing 100 ppm of titanium) (used as a depolymerization catalyst and a transesterification catalyst) (TYTAN AQ5000 purchased from Borica). Among them, the depolymerization temperature was 230 °C, and the depolymerization pressure was about 0.8 kg / cm when the bottle flakes were not completely dissolved yet. 2 , and about 3.0 kg / cm after the bottle flakes were completely dissolved. 2It was adjusted and 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 a transesterification reaction. Among them, the transesterification reaction temperature was about 425°C and 0.2 kg / cm 2 The reaction was carried out for 3 hours under a pressure of and under 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. Thereafter, 1248 g of PTMEG1000 (FAS PTMG purchased from Formosa Asahi, molecular weight 1000), 1248 g of PTMEG2000 (FAS PTMG purchased from Formosa Asahi, molecular weight 2000), 1664 g of PTMEG3000 (FAS PTMG purchased from Formosa Asahi, molecular weight 3000), 8 g of an antioxidant (pentaerythritol tetrakis[3-(3’,5’-di-tert-butyl-4’-hydroxyphenyl)propionate], Irganox (registered trademark) 1010 purchased from BASF), 2 g of sodium acetate (auxiliary catalyst) (purchased from Air Water Performance Chemicals), and titanium citrate chelate (polymerization catalyst) with a titanium addition amount of 50 ppm (TYTAN AQ5000 purchased from Borica) were mixed with the BHBT ester compound.

[0054] Thereafter, prepolymerization 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. Thereafter, 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 to 260°C, and the reaction time was set to about 1 hour to 2 hours until the product reached a viscosity of about 1.4 dL / g to 1.6 dL / g, thereby obtaining a thermoplastic polyester elastomer.

[0055] Example 2

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

[0057] Example 3

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

[0059] Comparative Example 1

[0060] Comparative Example 1 is similar to the manufacturing method of Example 1. The polymerization catalyst used in Comparative Example 1 is butyl titanate (TYTAN TNBT purchased from Borica).

[0061] Comparative Example 2

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

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

[0064]

Table 1

[0065] As can be seen from Table 1, under the same manufacturing conditions, the thermoplastic polyester elastomers produced in Examples 1 to 3 using the chelate-type titanium catalyst reached the thermoplastic polyester elastomers that meet the viscosity and hue requirements within a shorter time compared with Comparative Example 1 (using butyl titanate as the polymerization catalyst) and Comparative Example 2 (using isopropyl titanate as the polymerization catalyst). In addition, since the chelate-type titanium catalyst has the characteristic of being difficult to deactivate, it is not necessary to separately add a catalyst in the transesterification reaction of Examples 1 to 3, and the amount of catalyst used can be reduced.

[0066] In summary, the manufacturing method of the thermoplastic polyester elastomer of the present invention manufactures a thermoplastic polyester elastomer by subjecting polyester recycled materials to a depolymerization reaction, a transesterification reaction, and a polymerization reaction, effectively recovers and reuses the discarded PET to reduce the environmental load, and can achieve the goals of environmental protection and a circular economy. In addition, the catalysts used in the depolymerization reaction, the transesterification reaction, and the polymerization reaction each contain a chelate-type titanium catalyst. Therefore, the reaction rate can be increased, and it has a good catalytic effect and can reduce the overall manufacturing cost.

[0067] Although the present invention has been disclosed as above in the embodiments, it is not used to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the appended patent claims.

Claims

1. Providing a polyester recycled material containing polyethylene terephthalate; Subjecting the polyester recycled material to a depolymerization reaction with ethylene glycol; Subjecting the product obtained from the depolymerization reaction to a transesterification reaction with an aliphatic diol; Obtaining a thermoplastic polyester elastomer by subjecting the product obtained from the transesterification reaction to a polymerization reaction with a long-chain poly(alkyl diol); including; The catalysts used in the depolymerization reaction, the transesterification reaction, and the polymerization reaction each contain a chelate-type titanium catalyst, and the chelate-type titanium catalyst is selected from at least one of the group consisting of titanium phosphate ester chelate, titanium citrate chelate, and hydroxy acid ester titanium chelate; A method for producing a thermoplastic polyester elastomer.

2. The method for producing a thermoplastic polyester elastomer according to Claim 1, wherein the catalysts used in the depolymerization reaction, the transesterification reaction, and the polymerization reaction are all the same.

3. The method for producing a thermoplastic polyester elastomer according to Claim 1, wherein the long-chain poly(alkyl diol) contains polyethylene glycol or polytetramethylene ether glycol.

4. 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.

5. The method for producing a thermoplastic polyester elastomer according to Claim 1, wherein the product obtained from the transesterification reaction contains bis-hydroxypropyl terephthalate and / or bis-hydroxybutyl terephthalate.

6. The method for producing a thermoplastic polyester elastomer according to Claim 1, wherein the addition amount of the long-chain poly(alkyl diol) during the polymerization reaction accounts for 20% to 60% by weight of the total weight of the reactants in the polymerization reaction.

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

8. 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.

9. The method for producing a thermoplastic polyester elastomer according to Claim 1, further including adding an antioxidant during the polymerization reaction.

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