Polyesters based on diethylene glycol or its esterified compounds, their preparation methods and products

Abstract

This invention relates to a polyester based on diethylene glycol or its esterified form, a method for preparing the polyester, and products thereof. The method comprises the following steps: reacting a first mixed reaction system containing diethylene glycol or its esterified form, a diol, and an esterification or transesterification catalyst under a protective atmosphere to obtain an intermediate product, wherein the diol includes alicyclic diols and / or butanediol, the alicyclic diol having at least two conformations capable of interconversion; and reacting a second mixed reaction system containing the intermediate product and a stabilizer under vacuum conditions. The resulting polyester exhibits excellent heat resistance, toughness, and biodegradability, and can be used to prepare food packaging materials, mulch films, tissue engineering materials, and other products, with wide applications.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to polyesters based on diethylene glycol or its esterifications, as well as their preparation methods and products. Background Technology

[0002] Currently, widely used polyesters include polylactic acid (PLA), polyhydroxyalkanoate (PHA), polyglycolic acid (PGA), and polybutylene succinate (PBS). Among them, polylactic acid (PLA) is the most promising candidate to replace petroleum-based polymer materials due to its biomass source and biodegradability. However, polylactic acid is hard and brittle, which is not conducive to processing into products. In addition, polylactic acid has poor heat resistance, which greatly limits its application range. Summary of the Invention

[0003] Therefore, it is necessary to provide a polyester based on diethylene glycol or its esterified form, as well as its preparation method and products, to address the above-mentioned problems. This polyester has excellent heat resistance, toughness, and biodegradability, and can be used to prepare food packaging materials, mulch films, tissue engineering materials, and other products, with a wide range of applications.

[0004] This invention provides a method for preparing polyester based on diethylene glycol or its esterified form, comprising the following steps:

[0005] A first mixed reaction system comprising diethylene glycol or its esterified form, a diol, and an esterification or transesterification catalyst is reacted under a protective atmosphere to yield an intermediate product, wherein the diol comprises an alicyclic diol and / or butanediol, the alicyclic diol having at least two interconvertible conformations; and

[0006] The second mixed reaction system containing the intermediate product and the stabilizer is reacted under vacuum conditions to obtain a polyester based on diethylene glycol or its esterification.

[0007] In one embodiment, the molar ratio of butanediol to alicyclic diol is 1:9-9:1.

[0008] In one embodiment, the alicyclic diol includes at least one of cis-1,4-cyclohexanediol, trans-1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 4,4-bicyclohexanediol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, tricyclodecanediol, or pentacyclopentadecanediol.

[0009] In one embodiment, when the alicyclic diol comprises cis-1,4-cyclohexanediethanol and trans-1,4-cyclohexanediethanol, the molar ratio of cis-1,4-cyclohexanediethanol to trans-1,4-cyclohexanediethanol is 0.25:1 to 4:1.

[0010] In one embodiment, the molar ratio of the diol to the diethylene glycol or its esterified form is 120:100-300:100.

[0011] In one embodiment, the esterification or transesterification catalyst includes at least one of zinc-based catalysts, manganese-based catalysts, titanium-based catalysts, and tin-based catalysts, and the molar ratio of the esterification or transesterification catalyst to the diethylene glycol acid or its esterified form is 0.3:1000-3.0:1000.

[0012] And / or, the stabilizer is selected from phosphorus-based stabilizers, and the molar ratio of the stabilizer to the diethylene glycol or its esterified form is 0.4:1000-3.0:1000.

[0013] In one embodiment, when the esterification or transesterification catalyst is selected from zinc-based catalysts, a polycondensation catalyst is further added in the step of reacting the second mixed reaction system containing the intermediate product and the stabilizer under vacuum conditions. The polycondensation catalyst includes at least one of titanium-based catalysts, tin-based catalysts, antimony-based catalysts, and germanium-based catalysts. The molar ratio of the polycondensation catalyst to the diethylene glycol acid or its esterified form is 0.3:1000-3.0:1000.

[0014] In one embodiment, the first mixed reaction system is reacted under a protective atmosphere at a temperature of 160°C-240°C for 2-6 hours. In the step of reacting the second mixed reaction system under vacuum conditions, the vacuum degree is within 200 Pa, the temperature is 220°C-290°C, and the time is 1.5-6 hours.

[0015] A polyester based on diethylene glycol or its esterified form is prepared by the method described above for preparing a polyester based on diethylene glycol or its esterified form.

[0016] An article made of a polyester based on diethylene glycol or its esterification as described above.

[0017] In the method for preparing polyester based on diethylene glycol or its esters provided by this invention, the ether-oxygen bonds in the structure of diethylene glycol or its esters endow the polyester segments with excellent flexibility, which is beneficial to the regular arrangement of polyester segments and promotes crystallization. Furthermore, diethylene glycol or its esters have high reactivity, which can increase the molecular weight of the polyester, thereby giving the polyester excellent heat resistance and toughness. At the same time, when the diol includes alicyclic diols, alicyclic diols have greater rigidity and spatial non-planar structure than butanediol, which can further improve the heat resistance of the polyester. Moreover, the conformations of alicyclic diols can interconvert. When the polyester is impacted, the conformational transformation can absorb some energy, thereby improving the impact resistance of the polyester, that is, improving the toughness of the polyester. In addition, diethylene glycol or its esters and diols work synergistically to further improve the heat resistance and toughness of the prepared polyester. In addition, the polyester does not contain aromatic structures in its structural formula, therefore, the polyester has excellent biodegradability.

[0018] Because the diethylene glycol-based polyester provided by this invention has excellent temperature resistance, toughness and degradation performance, the products made from this polyester can be well applied in food packaging materials, mulch films, fibers, tissue engineering materials and other fields, which greatly expands the application fields and scope of polyester. Attached Figure Description

[0019] Figure 1 It is the polybutylene diethylene glycol ester prepared in Example 1. 1 H-NMR spectrum;

[0020] Figure 2 This is the DSC curve of poly(diethylene glycol) butylene glycol ester prepared in Example 1;

[0021] Figure 3 This is the TGA spectrum of polybutylene diethylene glycol ester prepared in Example 1;

[0022] Figure 4 This is the DSC curve of the poly(diethylene glycol) butanediol-1,4-cyclohexanediethanol copolyester prepared in Example 2.

[0023] Figure 5 This is the TGA spectrum of the poly(diethylene glycol) butanediol-1,4-cyclohexanediethanol copolyester prepared in Example 2. Detailed Implementation

[0024] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] The following will further describe the polyester based on diethylene glycol or its esterified form, its preparation method, and the product provided by the present invention.

[0027] The present invention provides a method for preparing polyester based on diethylene glycol or its esterified form, comprising the following steps:

[0028] S10, a first mixed reaction system comprising diethylene glycol or its esterified form, a diol, and an esterification or transesterification catalyst is reacted under a protective atmosphere to obtain an intermediate product; and

[0029] S20 involves reacting a second mixed reaction system containing intermediates and stabilizers under vacuum conditions to obtain a polyester based on diethylene glycol or its esterified form.

[0030] In the method for preparing polyester based on diethylene glycol or its esterifications provided by the present invention, the ether oxygen bond in the structure of diethylene glycol or its esterifications imparts excellent flexibility to the polyester chain segments, which is beneficial to the regular arrangement of the polyester chain segments and promotes crystallization. Furthermore, diethylene glycol or its esterifications have high reactivity, which can increase the molecular weight of the polyester, thereby giving the polyester excellent heat resistance and toughness.

[0031] Specifically, in the first mixed reaction system of step S10, the diol includes alicyclic diols and / or butanediol. It is understood that, in one embodiment, all the diols are selected from butanediol; in another embodiment, all the diols are selected from alicyclic diols; in yet another embodiment, the diols include both butanediol and alicyclic diols; the molar ratio of the diol to diethylene glycol or its esterified form is 120:100-300:100.

[0032] In one embodiment, butanediol includes 1,2-butanediol, 1,3-butanediol and 1,4-butanediol. Compared with 1,2-butanediol and 1,3-butanediol, 1,4-butanediol can make the polyester chain segments more regularly arranged, which is more conducive to the crystallization of polyester. Therefore, butanediol is preferably selected from 1,4-butanediol.

[0033] It should be noted that when the diol includes an alicyclic diol, the alicyclic diol has at least two conformations that can interconvert. The alicyclic diol has greater rigidity and a non-planar spatial structure than butanediol, which can further improve the heat resistance of the polyester. In turn, the diethylene glycol or its esterified form and the diol work together to further improve the heat resistance and toughness of the prepared polyester.

[0034] It should be noted that, unlike cyclopropane which has only one conformation (planar conformation), the alicyclic structures in other alicyclic diols have two or more conformations, enabling conformational transformation. The conformations of alicyclic structures with different numbers of carbon atoms are named differently. Six-membered alicyclic structures have boat and chair conformations, while five-membered alicyclic structures have envelope and half-chair conformations. The conformational transformation of alicyclic diols can further improve the toughness of polyesters. For example, the six-membered alicyclic structure in 1,4-cyclohexanediethanol has both boat and chair conformations, which can interconvert. When polyester materials are subjected to impact, the six-membered alicyclic structure can absorb some energy through conformational transformation, thereby improving impact resistance, i.e., increasing toughness.

[0035] In one embodiment, the alicyclic diol comprises 1,4-cyclohexanediethanol. 1,2-Cyclohexanediethanol 1,3-Cyclohexanediethanol 4,4-Bicyclohexanediol 1,4-Cyclohexanediol 1,3-Cyclohexanediol 1,2-Cyclohexanediol Tricyclodecanediethanol Pentacyclic pentadecanediol At least one of them.

[0036] In one embodiment, 1,4-cyclohexanediethanol is selected from at least one of cis-1,4-cyclohexanediethanol or trans-1,4-cyclohexanediethanol, and the molar ratio of cis-1,4-cyclohexanediethanol to trans-1,4-cyclohexanediethanol is 0.25:1 to 4:1.

[0037] When the diol includes butanediol and alicyclic diol, in one embodiment, the molar ratio of butanediol to alicyclic diol is 1:9-9:1, and in order to better balance the crystallization ability and tensile toughness of the polyester, it is further preferred to be 7:3-5:5.

[0038] In one embodiment, the esterification or transesterification catalyst in the first mixed reaction system of step S10 includes at least one of zinc-based catalysts, manganese-based catalysts, titanium-based catalysts, and tin-based catalysts; the molar ratio of the esterification or transesterification catalyst to diethylene glycol or its esterified form is 0.3:1000-3.0:1000.

[0039] In one embodiment, the zinc-based catalyst includes, but is not limited to, zinc acetate; the manganese-based catalyst includes, but is not limited to, manganese acetate; the titanium-based catalyst includes, but is not limited to, at least one of tetrabutyl titanate, isopropyl titanate, titanium dioxide, or inorganic supported titanium catalyst; and the tin-based catalyst includes, but is not limited to, at least one of dibutyltin oxide, stannous isooctanoate, monobutyltriisooctanoate, and dioctyltin oxide.

[0040] In one embodiment, the first mixed reaction system is reacted at a temperature of 160°C-240°C for 2-6 hours under a protective atmosphere, wherein the protective atmosphere can be a nitrogen atmosphere or an inert gas atmosphere.

[0041] In the second mixed reaction system of step S20, the stabilizer is selected from phosphorus-based stabilizers, including but not limited to at least one of phosphorous acid, hypophosphite, pyrophosphate, ammonium phosphate, trimethyl phosphate, dimethyl phosphate, triphenyl phosphate, diphenyl phosphate, triphenyl phosphite, diphenyl phosphite, ammonium phosphite, and ammonium dihydrogen phosphate. The molar ratio of the stabilizer to diethylene glycol or its esterified form is 0.4:1000-3.0:1000.

[0042] In one embodiment, particularly when the esterification or transesterification catalyst is selected from zinc-based catalysts, a polycondensation catalyst is also added during the step of reacting the second mixed reaction system containing the intermediate product and the stabilizer under vacuum conditions. The polycondensation catalyst includes at least one of titanium-based, tin-based, antimony-based, or germanium-based catalysts. It is understood that the selection of titanium-based or tin-based catalysts can refer to the selection of titanium-based or tin-based catalysts in esterification or transesterification catalysts. The molar ratio of the polycondensation catalyst to diethylene glycol or its esterified form is 0.3:1000-3.0:1000.

[0043] In one embodiment, the antimony-based catalyst includes, but is not limited to, at least one of antimony trioxide, antimony glycolate, antimony acetate, and antimony polyethylene glycol; the germanium-based catalyst includes, but is not limited to, germanium dioxide and / or germanium oxide.

[0044] In one embodiment, in the step of reacting the second mixed reaction system under vacuum conditions, the vacuum degree is within 200 Pa, the temperature is 220℃-290℃, and the time is 1.5h-6h.

[0045] The present invention provides a method for preparing polyester based on diethylene glycol or its esterified form using an esterification-polymerization process. This method is simple, easy to operate, highly controllable, and easy to implement, making it suitable for large-scale industrial production. It achieves the simple preparation of polyester with excellent temperature resistance and toughness.

[0046] The present invention also provides a polyester based on diethylene glycol or its esterified form, which is prepared by the above-described method for preparing a polyester based on diethylene glycol or its esterified form.

[0047] The polyester based on diethylene glycol provided by the present invention has excellent temperature resistance and toughness. In one embodiment, the polyester based on diethylene glycol or its esterification has a glass transition temperature of -30°C to 150°C, a melting point of 60°C to 80°C, and an elongation at break of 100% to 1000%.

[0048] In addition, since polyester does not contain aromatic structures in its structural formula, it has excellent biodegradability. In one embodiment, the polyester film has rapid degradation properties in seawater, with a mass loss of 30-80% after 30 days.

[0049] The present invention also provides an article made of a polyester based on diethylene glycol or its esterification as described above.

[0050] In one embodiment, the step of preparing an article from a diethylene glycol-based polyester includes: first preparing the diethylene glycol-based polyester into polyester particles, and then further preparing it into an article.

[0051] In one embodiment, the step of preparing polyester granules from diethylene glycol-based polyester includes the following steps: melt extrusion and granulation of the diethylene glycol-based polyester.

[0052] In one embodiment, the step of preparing polyester granules into an article includes melting and extruding the polyester granules and casting the molten fluid onto a roller to obtain a cast sheet; then stretching the cast sheet longitudinally and transversely to obtain a polyester film or sheet.

[0053] The diethylene glycol-based polyester provided by this invention has excellent temperature resistance, toughness, and biodegradability. As a result, products made from this polyester can be well applied in food packaging materials, mulch films, fibers, tissue engineering materials, and other application scenarios, greatly expanding the application fields and scope of polyester.

[0054] The following specific examples will further illustrate polyesters based on diethylene glycol or its esterifications, their preparation methods, and products.

[0055] In the following examples, the proton nuclear magnetic resonance spectrum... 1 H-NMR was measured on a Bruker 400 AVANCE Ⅲ Spectrometer instrument, 400 MHz, CF3COOD.

[0056] In the following examples, the intrinsic viscosity was determined using phenol / tetrachloroethane (1:1 m / m) as solvent at 30 ± 0.05 °C using an Ubbelohde viscometer, and the intrinsic viscosity [η] of the polyester and copolyester was calculated according to formulas (1) and (2).

[0057] η sp =(t1-t0) / t0 formula (1)

[0058] [η]=[(1+1.4η sp ) 1 / 2 -1] / 0.7c Formula (2)

[0059] Where: t0 is the solvent flow time (s), t1 is the solution flow time (s), and c is the solution concentration, 5 g / L.

[0060] In the following examples, thermal analysis was performed using a differential scanning calorimeter (Mettler Toledo DSC) at a heating rate of 10 °C / min in an N2 atmosphere, with a temperature range of 25 °C to 300 °C.

[0061] In the following examples, thermogravimetric analysis (TGA) was performed on a Perkin-Elmer Diamond TG / DTA at a heating rate of 10 °C / min and a temperature range of 50–800 °C.

[0062] In the following examples, the elongation at break test was performed using an Instron 5567 universal testing machine with a sample size of 20.0 mm in length, 2.0 mm in width, and 1.0 mm in thickness, and a tensile speed of 20 mm / min.

[0063] Example 1

[0064] Diethylene glycol and 1,4-butanediol were added to the reactor at a molar ratio of 1:1.6. Then, dibutyltin oxide oxidizing catalyst with a molar amount of 1‰ of diethylene glycol was added. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180°C for esterification reaction. After 4.0 h of reaction, tetrabutyl titanate condensation catalyst with a molar amount of 1.0‰ of diethylene glycol and triphenyl phosphate stabilizer with a molar amount of 1.0‰ were added. The temperature was gradually increased to 200°C and the vacuum degree was gradually reduced to 50 Pa. After 4 hours of reaction, polybutylene diethylene glycol ester was obtained, and its structural formula is shown in formula (1), where n is 218.

[0065]

[0066] Poly(diethylene glycol) butanediol (PEG) was subjected to intrinsic viscosity, nuclear magnetic resonance (NMR), digital subtraction angiography (DSC), total magnetic resonance spectroscopy (TGA), mechanical properties, and composting degradation tests. The intrinsic viscosity of PEG was 1.27 dL / g. 1 H-NMR such as Figure 1 As shown, the DSC curve is as follows: Figure 2 As shown, from Figure 2 It can be seen that the glass transition temperature is -28℃, the melting point is 69℃, the enthalpy of fusion is 53.2 J / g, and the thermal weight loss T 5％ The temperature is 336℃, and the TGA spectrum is as follows: Figure 3 As shown, thermogravimetric analysis (T0) 5％ Poly(diethylene glycol) butanediol was prepared into strips and films at 336℃. The elongation at break of the strips was 447%, and the tensile modulus was 287 MPa. The mass loss of the film was tested under composting conditions. After 30 days of degradation, the mass loss of the film reached 49.1%.

[0067] Example 2

[0068] Diethylene glycol, 1,4-butanediol, and trans-1,4-cyclohexanediethanol were added to a reactor in a molar ratio of 1:1.2:0.4. Then, dibutyltin oxide oxidizing catalyst with a molar amount of 1‰ of diethylene glycol was added. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180℃ for esterification reaction. After 4.0h of reaction, tetrabutyl titanate condensation catalyst with a molar amount of 1.0‰ of diethylene glycol and triphenyl phosphate stabilizer with a molar amount of 1.0‰ were added. The temperature was gradually increased to 220℃ and the vacuum was gradually reduced to 50Pa. After 4h of reaction, poly(diethylene glycol) butanediol and 1,4-cyclohexanediethanol copolyester were obtained, and its structural formula is shown in formula (2), where n is 129 and m is 81.

[0069]

[0070] The intrinsic viscosity, nuclear magnetic resonance (NMR), DSC, TGA, mechanical properties, and composting degradation of poly(butylene diglycol)-1,4-cyclohexanediethanol copolyester were tested. The DSC curves are shown below. Figure 4 As shown, the TGA spectrum is as follows: Figure 5 As shown, the intrinsic viscosity of poly(butylene diglycol)-1,4-cyclohexanediethanol copolyester is 0.98 dL / g, and the glass transition temperature is 27℃. The poly(butylene diglycol)-1,4-cyclohexanediethanol copolyester was made into strips and films. The elongation at break of the strips was 413%, and the film was degraded under composting conditions for 30 days with a mass loss of 32.7%.

[0071] Example 3

[0072] Diethylene glycol, 1,4-butanediol, and pentacyclic pentadecanediol were added to the reactor in a molar ratio of 1:0.6:1. Then, dibutyltin oxide oxidizing catalyst with a molar amount of 1‰ of diethylene glycol was added. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180℃ for esterification reaction. After 4.0h of reaction, tetrabutyl titanate condensation catalyst with a molar amount of 1.0‰ of diethylene glycol and triphenyl phosphate stabilizer with a molar amount of 1.0‰ were added. The temperature was gradually increased to 220℃ and the vacuum was gradually reduced to 50Pa. After 4 hours of reaction, poly(diethylene glycol butanediol pentacyclic pentadecanediol) copolyester was obtained, and its structural formula is shown in formula (3), where n is 84 and m is 59.

[0073]

[0074] The intrinsic viscosity, nuclear magnetic resonance, DSC, TGA, mechanical properties, and composting degradation of poly(butylene diethylene glycol) pentacyclic pentadecanediol copolyester were tested. The intrinsic viscosity of poly(butylene diethylene glycol) pentacyclic pentadecanediol copolyester was 0.92 dL / g, and the glass transition temperature was 73℃. The poly(butylene diethylene glycol) pentacyclic pentadecanediol copolyester was made into strips and films. The elongation at break of the strips was 364%. The film was degraded under composting conditions for 30 days with a mass loss of 32.7%.

[0075] Example 4

[0076] Diethylene glycol, 1,4-butanediol, trans-1,4-cyclohexanediethanol, and cis-1,4-cyclohexanediethanol were added to a reactor in a molar ratio of 1:1.2:0.08:0.32. Then, 1‰ of the molar amount of diethylene glycol was added as an esterification or transesterification catalyst to oxidize dibutyltin. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180°C for esterification reaction. After 4.0 h of reaction, 1.0‰ of the molar amount of diethylene glycol was added as a polycondensation catalyst tetrabutyl titanate and 1.0‰ of the stabilizer triphenyl phosphate. The temperature was gradually increased to 220°C and the vacuum was gradually reduced to 50 Pa. After 4 hours of reaction, poly(diethylene glycol) butanediol and 1,4-cyclohexanediethanol copolyester were obtained, and its structural formula is shown in formula (4), where x is 129, y is 15, and z is 64.

[0077]

[0078] The intrinsic viscosity, nuclear magnetic resonance (NMR), DSC, TGA, mechanical properties, and composting degradation of poly(butylene glycol)-1,4-cyclohexanediethanol copolyester were tested. The intrinsic viscosity of the poly(butylene glycol)-1,4-cyclohexanediethanol copolyester was 0.81 dL / g, and the glass transition temperature was 19℃. Strips and films were prepared from the poly(butylene glycol)-1,4-cyclohexanediethanol copolyester. The elongation at break of the strips was 289%. The film underwent 47.2% mass loss after 30 days of composting degradation.

[0079] Example 5

[0080] Diethylene glycol, 1,4-butanediol, trans-1,4-cyclohexanediethanol, and cis-1,4-cyclohexanediethanol were added to a reactor in a molar ratio of 1:1.2:0.32:0.08. Then, 1‰ of the molar amount of diethylene glycol was added as an esterification or transesterification catalyst to oxidize dibutyltin. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180°C for esterification reaction. After 4.0 h of reaction, 1.0‰ of the molar amount of diethylene glycol was added as a polycondensation catalyst tetrabutyl titanate and 1.0‰ of the stabilizer triphenyl phosphate. The temperature was gradually increased to 220°C and the vacuum was gradually reduced to 50 Pa. After 4 hours of reaction, poly(diethylene glycol) butanediol and 1,4-cyclohexanediethanol copolyester were obtained, and its structural formula is shown in formula (4), where x is 132, y is 68, and z is 17.

[0081]

[0082] The intrinsic viscosity, nuclear magnetic resonance (NMR), DSC, TGA, mechanical properties, and composting degradation of poly(butylene glycol)-1,4-cyclohexanediethanol copolyester were tested. The intrinsic viscosity of the poly(butylene glycol)-1,4-cyclohexanediethanol copolyester was 0.87 dL / g, and the glass transition temperature was 23℃. Strips and films were prepared from the poly(butylene glycol)-1,4-cyclohexanediethanol copolyester. The elongation at break of the strips was 473%. The film underwent 30 days of composting degradation, resulting in a mass loss of 39.1%.

[0083] Example 6

[0084] Diethylene glycol, 1,4-butanediol, and tricyclodecanediethanol were added to the reactor in a molar ratio of 1:0.8:1. Then, 1‰ of the molar amount of diethylene glycol was added as an esterification or transesterification catalyst to oxidize dibutyltin. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180℃ for esterification reaction. After 4.0h of reaction, 1.0‰ of the molar amount of diethylene glycol was added as a polycondensation catalyst tetrabutyl titanate and 1.0‰ of the stabilizer triphenyl phosphate. The temperature was gradually increased to 230℃ and the vacuum was gradually reduced to 50Pa. After 6 hours of reaction, poly(diethylene glycol butanediol) tricyclodecanediethanol copolyester was obtained, and its structural formula is shown in formula (5), where n is 127 and m is 35.

[0085]

[0086] The intrinsic viscosity, nuclear magnetic resonance, DSC, TGA, mechanical properties, and composting degradation of poly(butylene glycol tricyclodecanediethanol) copolyester were tested. The intrinsic viscosity of the poly(butylene glycol tricyclodecanediethanol) copolyester was 0.63 dL / g, and the glass transition temperature was 57℃. The poly(butylene glycol pentacyclic pentadecanediol) copolyester was made into strips and films. The elongation at break of the strips was 402%. The film was degraded under composting conditions for 30 days with a mass loss of 43.7%.

[0087] Comparative Example 1

[0088] Using lactide as a raw material, 0.8‰ of stannous octoate was added, and the temperature was gradually raised to 150℃. The reaction was carried out for 5.0 h, and the lactide was ring-opening polymerized to obtain polylactic acid, which has a glass transition temperature of 55℃ and a melting point of 170℃. The polylactic acid was made into a sample, and the elongation at break of the sample was 5%.

[0089] Comparative Example 2

[0090] Diethylene glycol and 1,6-hexanediol were added to the reactor at a molar ratio of 1:1.6. Then, dibutyltin oxide oxidizing catalyst with a molar amount of 1‰ of diethylene glycol was added. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180°C for esterification reaction. After 4.0 h of reaction, tetrabutyl titanate condensation catalyst with a molar amount of 1.0‰ of diethylene glycol and triphenyl phosphate stabilizer with a molar amount of 1.0‰ were added. The temperature was gradually increased to 220°C and the vacuum degree was gradually reduced to 50 Pa. After 4 hours of reaction, poly(diethylene glycol) 1,6-hexanediol homopolymer was obtained, and its structural formula is shown in formula (6), where n is 216.

[0091]

[0092] The intrinsic viscosity, nuclear magnetic resonance, DSC, TGA and mechanical properties of poly(diethylene glycol) homopolymer were tested. The intrinsic viscosity of poly(diethylene glycol) homopolymer was 1.03 dL / g, the melting point was 46℃ and the enthalpy of fusion was 64.1 J / g. The poly(diethylene glycol) homopolymer was made into a sample. The elongation at break of the sample was 578% and the tensile modulus was 19 MPa.

[0093] Comparative Example 3

[0094] Diethylene glycol, 1,4-butanediol, and 1,1-cyclopropanediethanol were added to a reactor in a molar ratio of 1:1.3:0.3. Then, dibutyltin oxide oxidizing catalyst with a molar amount of 1‰ of diethylene glycol was added. Under the protection of high-purity nitrogen, the temperature was gradually increased to 180°C for esterification reaction. After 4.0 h of reaction, tetrabutyl titanate condensation catalyst with a molar amount of 1.0‰ of diethylene glycol and triphenyl phosphate stabilizer with a molar amount of 1.0‰ were added. The temperature was gradually increased to 220°C and the vacuum degree was gradually reduced to 50 Pa. After 4 hours of reaction, poly(diethylene glycol-co-diethylene glycol-cyclopropanediethanol) copolyester was obtained, and its structural formula is shown in formula (7), where n is 163 and m is 71.

[0095]

[0096] The intrinsic viscosity, nuclear magnetic resonance (NMR), DSC, TGA, and mechanical properties of poly(butylene glycol diethylene glycol) copolyester were tested. The intrinsic viscosity of poly(butylene glycol diethylene glycol) copolyester was 0.84 dL / g, the melting point was 46℃, and the enthalpy of fusion was 64.1 J / g. The poly(butylene glycol diethylene glycol) copolyester was made into a strip, and the elongation at break of the strip was 73%.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a polyester based on diethylene glycol or its esterified form, characterized in that, Includes the following steps: A first mixed reaction system comprising diethylene glycol or its esterified form, a diol, and an esterification or transesterification catalyst is reacted under a protective atmosphere to yield an intermediate product, wherein the diol comprises an alicyclic diol and butanediol, the alicyclic diol having at least two interconvertible conformations, and the molar ratio of butanediol to the alicyclic diol being 1:9 to 9:1; and The second mixed reaction system containing the intermediate product and the stabilizer is reacted under vacuum conditions to obtain a polyester based on diethylene glycol or its esterification.

2. The method for preparing polyester based on diethylene glycol or its esterified form according to claim 1, characterized in that, The alicyclic diols include at least one of 4,4-bicyclohexanediol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, tricyclodecanediol, or pentacyclopentadecanediol.

3. The method for preparing polyester based on diethylene glycol or its esterified form according to claim 2, characterized in that, The alicyclic diol includes at least one of cis-1,4-cyclohexanediethanol, trans-1,4-cyclohexanediethanol, 1,2-cyclohexanediethanol, and 1,3-cyclohexanediethanol.

4. The method for preparing polyester based on diethylene glycol or its esterified form according to claim 3, characterized in that, When the alicyclic diol comprises cis-1,4-cyclohexanediethanol and trans-1,4-cyclohexanediethanol, the molar ratio of cis-1,4-cyclohexanediethanol to trans-1,4-cyclohexanediethanol is 0.25:1 to 4:

1.

5. The method for preparing polyester based on diethylene glycol or its esterified form according to any one of claims 1-4, characterized in that, The molar ratio of the diol to the diethylene glycol or its esterified form is 120:100-300:

100.

6. The method for preparing a polyester based on diethylene glycol or its esterified form according to any one of claims 1-4, characterized in that, The esterification or transesterification catalyst includes at least one of zinc-based catalysts, manganese-based catalysts, titanium-based catalysts, and tin-based catalysts, and the molar ratio of the esterification or transesterification catalyst to the diethylene glycol acid or its esterified form is 0.3:1000-3.0:1000. And / or, the stabilizer is selected from phosphorus-based stabilizers, and the molar ratio of the stabilizer to the diethylene glycol or its esterified form is 0.4:1000-3.0:1000.

7. The method for preparing polyester based on diethylene glycol or its esterified form according to any one of claims 1-4, characterized in that, When the esterification or transesterification catalyst is selected from zinc-based catalysts, a polycondensation catalyst is also added in the step of reacting the second mixed reaction system containing the intermediate product and the stabilizer under vacuum conditions. The polycondensation catalyst includes at least one of titanium-based catalysts, tin-based catalysts, antimony-based catalysts, and germanium-based catalysts. The molar ratio of the polycondensation catalyst to the diethylene glycol acid or its esterified form is 0.3:1000-3.0:1000.

8. The method for preparing polyester based on diethylene glycol or its esterified form according to any one of claims 1-4, characterized in that, The first mixed reaction system is carried out under a protective atmosphere at a temperature of 160℃-240℃ for 2h-6h. In the second mixed reaction system, the reaction is carried out under vacuum conditions with a vacuum degree of less than 200Pa, a temperature of 220℃-290℃, and a time of 1.5h-6h.

9. A polyester based on diethylene glycol or its esterified form, characterized in that, It is prepared by the method for preparing polyester based on diethylene glycol or its esterification as described in any one of claims 1-8.

10. An article characterized in that, The article is made of polyester based on diethylene glycol or its esterified form as described in claim 9.

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