High-transparency thermoplastic polyester elastomer and preparation method thereof

Abstract

The invention relates to a high-transparency thermoplastic polyester elastomer and a preparation method thereof.The method comprises the following steps that raw material monomers and a catalyst are mixed, the raw material monomers comprise binary acid monomers and dihydric alcohol monomers, the binary acid monomers comprise cyclic binary acid or ester thereof, and the dihydric alcohol monomers comprise dihydric alcohol monomers; the dihydric alcohol monomers comprise aliphatic dihydric alcohol, cyclic dihydric alcohol and polyether dihydric alcohol, carrying out esterification reaction in the atmosphere of protective gas to obtain an oligomer, carrying out pre-polycondensation on the oligomer, and carrying out final polycondensation under a vacuum condition to obtain the high-transparency thermoplastic polyester elastomer. Compared with the prior art, the prepared high-transparency thermoplastic polyester elastomer is good in light transmittance and controllable in mechanical property and light transmittance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a highly transparent thermoplastic polyester elastomer and its preparation method. Background Technology

[0002] Elastomers generally refer to materials that can recover their significant deformation after the removal of external force. Rubber is the earliest and most widely used elastomer by humankind. However, due to its thermosetting properties, rubber has limitations in terms of single-processability and recyclability. Subsequently, since the Bayer Company first prepared polyurethane (PU) in the 1940s, it was discovered that thermoplastic elastomers (TPEs) could effectively replace rubber in many applications due to their ease of multiple processing, and thus experienced rapid development.

[0003] Thermoplastic polyester elastomers (TPEEs) are typically polyether ester copolymers with highly crystalline, high-melting-point polyester blocks as hard segments and amorphous polyethers with low glass transition temperatures as soft segments. They are also known as polyester thermoplastic elastomers or polyester rubber. The amorphous polyether phase imparts resilience to the material, while the partially crystallized polyester hard segments form crystalline microdomains, acting as physical crosslinking points. TPEEs possess the elasticity of rubber and the strength of engineering plastics. The soft segments give them elasticity, making them rubber-like; the hard segments give them processability, making them plastic-like. Compared to rubber, they have better processability and a longer service life; compared to engineering plastics, they also have high strength, but with better flexibility and dynamic mechanical properties. TPEEs exhibit high strength, high elasticity, oil resistance, acid and alkali resistance, high temperature resistance, radiation resistance, and excellent dynamic mechanical properties. They have a wide operating temperature range of -50 to 180°C and a hardness range of 25 to 80 D. The initial research and development of TPEEs aimed to produce highly elastic fibers for the textile industry. However, TPEE has now become an irreplaceable high-performance new elastomer material, widely used in automotive, electronics, railway, and other fields. However, TPEE materials exhibit opacity due to the high degree of microphase separation between the hard polyester segment and the soft polyether segment, as well as the high crystallinity of the hard segment, hindering its application. Therefore, selecting suitable monomers to polymerize the soft and hard segments is an effective way to improve the transparency of polyester elastomers, broaden their applications, and achieve high-value utilization. Transparent polyester elastomers possess the excellent mechanical properties and unique optical properties of traditional polyester elastomers, and can be used as bulletproof glass interlayers, transparent protective products, automotive parts, etc. Developing a highly transparent TPEE is of great significance.

[0004] Patent CN117304656A discloses a high-transparency thermoplastic polyester elastomer and its preparation method. Specifically, the method involves mixing TPEE, plasticizer, nucleating agent, antioxidant, lubricant, and other additives, and processing the mixture using a twin-screw extruder to obtain the high-transparency thermoplastic polyester elastomer. The resulting transparent TPEE exhibits excellent mechanical properties, but the material is a semi-transparent product with a light transmittance of only 15.8%, and no mechanism-based approach is used to control and prepare a product with higher transparency.

[0005] Patent CN113429749A discloses a highly transparent, low melt flow index thermoplastic polyester elastomer and its preparation method. Specifically, the method involves mixing TPEE, a clearing agent, a nucleating agent, and an antioxidant, and then processing the mixture through twin-screw extrusion to obtain a highly transparent polyester material. The resulting material has a low melt flow index and good light transmittance, but its mechanical properties are poor. It only alters the lattice size by adding a clearing agent to make the material appear transparent macroscopically; it does not utilize in-situ polymerization to prepare TPEEs with different mechanical properties and light transmittance.

[0006] Patent CN117343502A discloses a transparent and toughened PET material and its preparation method. Specifically, the method involves mixing polyethylene terephthalate (PET), polyethylene terephthalate-1,4-cyclohexanediethanol (PCTG), and an antioxidant, and then extruding the mixture using a twin-screw extruder to prepare the transparent and toughened PET material. The patent details the preparation of the modified PCTG, which involves mixing terephthalic acid, ethylene glycol, 1,4-cyclohexanediethanol, and silver nanowires, and then polymerizing in situ to generate a modified PCTG masterbatch. The resulting modified PCTG exhibits good compatibility with PET, significantly improving the light transmittance and toughness of PET. Furthermore, the addition of silver nanowires enhances the material's antibacterial properties. However, the addition of metal through blending modification may pose a risk of metal leaching during prolonged use.

[0007] Patent CN117402335A discloses a transparent PET material, its manufacturing method, and PET products. Specifically, the method involves esterifying terephthalic acid and ethylene glycol to produce ethylene terephthalate, followed by copolymerizing the ethylene terephthalate with isophthalic acid and 1,4-cyclohexanediethanol to prepare the transparent PET material. The resulting transparent PET material, through in-situ polymerization with isophthalic acid and 1,4-cyclohexanediethanol, alters the thermal behavior of the PET material, giving it high light transmittance. However, the material is a rigid plastic and cannot meet the market demand for flexible automotive interior materials.

[0008] Existing technologies for preparing transparent polyester elastomers are insufficient to achieve the preparation of highly transparent materials with balanced performance. Generally, inorganic substances such as metal salts are mixed into high molecular weight TPEE through blending modification. However, the modified fillers have problems such as poor compatibility, easy precipitation, and short service life.

[0009] Therefore, it is necessary to develop a highly transparent thermoplastic polyether ester elastomer based on molecular structure to fundamentally solve the problem.

[0010] Patent CN115073716A discloses a butenediol-based aliphatic-aromatic copolyester elastomer and its preparation method. The method involves esterification and polymerization of a diol containing 1,4-butenediol, an organic acid containing an aromatic diacid, an antioxidant, and a polymerization inhibitor under the action of a catalyst to obtain the butenediol-based aliphatic-aromatic copolyester elastomer. This patent exhibits excellent heat resistance and a high glass transition temperature, which can effectively reduce production costs; however, the patent does not demonstrate the mechanical properties and corresponding melt flow index of the aliphatic-aromatic polyester elastomer, thus limiting its application in flexible automotive interior trim.

[0011] Patent CN118388754A discloses a bio-based polyether ester elastomer and its preparation method. Using polyether glycol as the basic unit, a series of bio-based polyether ester elastomers with varying ether bond contents were synthesized through multi-component copolymerization design. The polyether ester elastomers were prepared by condensation polymerization of various monomers, including polyether glycol, aliphatic diol, and diacid. The bio-based polyether ester elastomer prepared by this patent exhibits good oil resistance and low-temperature resistance; however, since aromatic groups are not used as reactants, the material's mechanical strength and heat resistance are deficient, making it unsuitable for flexible automotive interior trim.

[0012] Patent CN110862524A discloses a bio-based high-transparency polymer film and its preparation method. First, using A, B, and isosorbide as main raw materials, a low-crystallinity biodegradable polyester is obtained through esterification or transesterification, pre-condensation, and final condensation reactions. Then, the low-crystallinity biodegradable polyester is subjected to hot-pressing treatment to obtain the bio-based high-transparency polymer film. In this case, A is furan dicarboxylic acid or its alkyl ester, and B is a fatty diol. However, this patent uses bio-based raw materials, resulting in higher production costs. Furthermore, the patent primarily applies to films and does not mention mechanical properties, making it unsuitable for flexible automotive interior trim. Summary of the Invention

[0013] The purpose of this invention is to overcome at least one defect of the prior art and provide a highly transparent thermoplastic polyester elastomer and its preparation method. The highly transparent thermoplastic polyester elastomer prepared by this invention has good light transmittance, and its mechanical properties and light transmittance are controllable.

[0014] The objective of this invention can be achieved through the following technical solutions:

[0015] One of the technical solutions of the present invention is to provide a highly transparent thermoplastic polyester elastomer, wherein the chemical structural formula of the unit of the elastomer is as follows:

[0016]

[0017] Wherein, a, b, and c are all non-zero integers, a:(a+b) is 0.1 to 0.95, c:(a+b+c) is 0.05 to 0.8, R1 is an alkyl group with 2 to 18 carbon atoms, R2 is an alicyclic, aromatic, or furan ring, wherein the aromatic ring is selected from one or more of benzene ring, biphenyl ring, and naphthalene ring, R3 is a polyether or polyester of a certain molecular weight, and R4 is an aliphatic saturated ring.

[0018] As a preferred technical solution, a:(a+b) is 0.5 to 0.95, c:(a+b+c) is 0.1 to 0.6, R1 is an alkyl group with 2 to 5 carbon atoms, R2 is a six-membered alicyclic ring or a benzene ring, and R3 is a polyether with a certain molecular weight.

[0019] One of the technical solutions of the present invention is to provide a method for preparing the aforementioned high-transparency thermoplastic polyester elastomer, the method comprising the following steps:

[0020] The raw material monomers and catalyst are mixed. The raw material monomers include diacid monomers and diol monomers. The diacid monomers include cyclic diacids or their esterifications. The diol monomers include aliphatic diols, cyclic diols and polyether diols. An esterification (ester exchange) reaction is carried out under a protective gas atmosphere to obtain oligomers. The oligomers are pre-condensed and then final-condensed under vacuum conditions to obtain a highly transparent thermoplastic polyester elastomer.

[0021] Further, the cyclic dicarboxylic acid or its esterified form is selected from one or more of terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, phthalic acid, dimethyl phthalate, 1,4-cyclohexanedicarboxylic acid, and dimethyl 1,4-cyclohexanedicarboxylic acid.

[0022] Furthermore, the aliphatic diol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol, and neopentanediol.

[0023] Furthermore, the cyclic diol is selected from one or more of 1,4-cyclohexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and isosorbide.

[0024] Furthermore, the polyether diol is selected from one or more of polyethylene glycol, polypropylene glycol, and polytetramethylene ether diol, and the number average molecular weight of the polyether diol is 200 to 2000.

[0025] Furthermore, the molar ratio of the dicarboxylic acid monomer to the diol monomer is 1:(1.05-3).

[0026] As a preferred technical solution, the molar ratio of the dicarboxylic acid monomer to the diol monomer is 1:(1.1~3).

[0027] Furthermore, the catalyst is selected from one or more catalysts with 1 to 12 carbon atoms selected from organoaluminum compounds, organotin compounds, and titanates.

[0028] Furthermore, the molar ratio of the catalyst to the raw material monomer is (0.0002~0.005):1.

[0029] As a preferred technical solution, the molar ratio of the catalyst to the raw material monomer is (0.0002~0.002):1.

[0030] As a preferred technical solution, the protective gas is selected from one or more of nitrogen, helium, and argon.

[0031] Furthermore, the esterification reaction is carried out at a temperature of 150–280°C, a rotation speed of 100–300 r / min, and a time of 0.5–4 h.

[0032] The pre-polymerization temperature is 180–280℃, the pressure is 3–10 kPa, and the time is 0.5–2 h.

[0033] The final polycondensation temperature is 180–280°C, the vacuum degree is 50–300 Pa, and the time is 1–8 h.

[0034] As a preferred technical solution, the esterification reaction is carried out at a temperature of 160–260°C for a time of 0.5–2 hours.

[0035] The pre-polymerization temperature is 180–260°C, and the time is 0.5–1 hour.

[0036] The final polycondensation temperature is 220–280°C, and the time is 1–6 hours.

[0037] As a preferred technical solution, the final polycondensation is followed by vacuum drying.

[0038] As a preferred technical solution, the vacuum drying temperature is 20-60℃, the vacuum degree is 300-500Pa, and the time is 6-24h.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The highly transparent thermoplastic polyester elastomer prepared by the preparation method of the present invention has high molecular weight, high transparency and good mechanical properties;

[0041] (2) The preparation method of the present invention reduces the crystallization properties of the material by adding different components in the in-situ polymerization stage, and prepares a highly transparent thermoplastic polyester elastomer while maintaining excellent mechanical properties.

[0042] (3) The preparation method of the present invention achieves control of molecular structure, molecular weight and ratio of soft and hard segments through in-situ polymerization. The preparation process is simple to operate and can be adjusted on the original process. By changing the formula, highly transparent thermoplastic polyester elastomers with different mechanical properties, softness and hardness, thermal behavior and light transmittance can be prepared. They can be used in transparent films, optical materials, medical materials and automotive parts that require high transparency. Attached Figure Description

[0043] Figure 1 This is the gel permeation chromatography (GPC) spectrum of the highly transparent thermoplastic polyester elastomer in Example 1 of the present invention;

[0044] Figure 2 This is a differential scanning calorimetry (DSC) single-stage cooling curve of the high-transparency thermoplastic polyester elastomer in Example 1 of the present invention;

[0045] Figure 3 This is a DSC secondary heating curve of the high-transparency thermoplastic polyester elastomer in Example 1 of the present invention;

[0046] Figure 4 This is an engineering stress-strain curve of the highly transparent thermoplastic polyester elastomer in Embodiment 1 of the present invention. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0048] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0049] In this embodiment and the comparative example, the raw material monomers of cyclic dicarboxylic acids or their esters, aliphatic diols, cyclic diols and polyether diols were all purchased from Maclean Biotechnology Co., Ltd., and the catalysts were purchased from Titan Technology Co., Ltd.

[0050] The highly transparent thermoplastic polyester elastomer in this embodiment has the following chemical structural formula:

[0051]

[0052] Wherein, a, b, and c are all non-zero integers, R1 is an alkyl group with 2 to 18 carbon atoms, preferably with 2 to 5 carbon atoms, R2 is an alicyclic, aromatic, or furan ring, the aromatic ring being selected from one or more of benzene ring, biphenyl ring, and naphthalene ring, preferably R2 is a six-membered alicyclic or benzene ring, R3 is a polyether or polyester of a certain molecular weight, preferably a polyether of a certain molecular weight, and R4 is an aliphatic saturated ring.

[0053] The test and characterization methods used for the elastomers in this embodiment and the comparative example are as follows:

[0054] T1, Intrinsic Viscosity (IV): The intrinsic viscosity of the elastomer was measured using an NCY-4 automatic viscometer from Shanghai Sida Co., Ltd.

[0055] The solvent used was a phenol / 1,1,2,2-tetrachloroethane mixed solution with a mass ratio of 1:1. The test was conducted using an Ubbelohde viscometer with an inner diameter of 0.84 mm in a constant temperature water bath at a temperature of 25±0.05℃.

[0056] The thermal properties of the elastomer, including T2, melting temperature, and crystallization temperature, were studied using a TA Q2000 differential scanning calorimeter (USA).

[0057] Under nitrogen atmosphere, 5–10 mg of elastomer was heated to 240 °C at a rate of 10 °C / min and held at that temperature for 10 min.

[0058] Then, the sample was cooled to 40°C at a rate of 10°C / min, and the cooling curve was recorded once, with the corresponding crystallization temperature (Tc) read.

[0059] Finally, the sample was heated to 240℃ at a rate of 10℃ / min, the secondary heating curve was recorded, and the corresponding melting temperature (Tm) was read.

[0060] T3, Molecular Weight: The molecular weight of the elastomer was determined using a Waters 1515 gel permeation chromatography system (USA).

[0061] The chromatographic column used was an Agilent PLgel 5μm MIXED-C, the mobile phase was hexafluoroisopropanol, the flow rate was 0.3 mL / min, and the standard substance was polymethyl methacrylate (PMMA).

[0062] T4. Mechanical properties: The tensile properties of the elastomer are tested using a universal testing machine.

[0063] The elastomer was hot-pressed into a 1 mm thick film, cut into dumbbell-shaped strips, placed at room temperature for 20 min, and subjected to tensile testing at a speed of 50 mm / min. At least five tests were performed on each elastomer.

[0064] T5. Light transmittance: The light transmittance of the elastomer was measured using a WGT-S light transmittance meter in accordance with GB / T 2410-2008, "Determination of light transmittance and haze of transparent plastics".

[0065] Example 1:

[0066] A highly transparent thermoplastic polyester elastomer and its preparation method are disclosed, with the specific steps as follows:

[0067] 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of polytetramethylene ether glycol (PTMG-1000) with a number average molecular weight of 1000 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190°C and the rotation speed was set to 200 rpm. n. An esterification (ester exchange) reaction was carried out for 1 hour to obtain oligomers. The oligomers were then subjected to pre-polymerization at 220℃ and 4kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and a high vacuum of 100Pa was used for final polymerization for 1.5 hours. During this period, the torque change was observed and the speed was gradually reduced. After the speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and a vacuum of 300Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0068] like Figure 1 As shown, based on the PMMA standard molecular weight curve, the number-average molecular weight of the high-transparency thermoplastic polyester elastomer in Example 1 was calculated to be 1.78 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.95 × 10 4 g / mol.

[0069] like Figure 2 As shown, based on the extreme value of the first cooling curve, the crystallization temperature of the high-transparency thermoplastic polyester elastomer in Example 1 is 69.9℃.

[0070] like Figure 3 As shown, based on the extreme values ​​of the secondary heating curve, the melting temperature of the high-transparency thermoplastic polyester elastomer in Example 1 was found to be 118.8℃.

[0071] like Figure 4As shown, the tensile strength of the high-transparency thermoplastic polyester elastomer at fracture in Example 1 was 24.62 MPa, and the elongation at break was 545.0%. Based on the slope of the curve in the initial stage of stretching, the tensile modulus of Example 1 was calculated to be 186.20 MPa.

[0072] The intrinsic viscosity of the elastomer in Example 1 was 1.43 dL / g, and the number-average molecular weight was 1.78 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.95 × 10 4 g / mol, crystallization temperature 69.9℃, melting temperature 118.8℃, tensile strength of the sample 24.62MPa, tensile modulus 186.20MPa, elongation at break 545.0%, and light transmittance 68%.

[0073] Example 2:

[0074] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.63 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.759), 0.35 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.297), 0.2 mol of PTMG-1000 (molar ratio of diacid monomer to diol monomer is 1:1.31), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000404:1) are added to the reaction vessel and mixed.

[0075] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0076] Add 0.9 mol of dimethyl terephthalate, 0.63 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.759), 0.35 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.297), and 0.2 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.31) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000404:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0077] In Example 2, the intrinsic viscosity of the elastomer was 1.33 dL / g, and the number-average molecular weight was 1.26 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.50 × 10⁻⁶ g / mol 4 g / mol, crystallization temperature 69.68℃, melting temperature 123.4℃, tensile strength of the sample 19.63MPa, tensile modulus 130.26MPa, elongation at break 763.1%, and light transmittance 86%.

[0078] Example 3:

[0079] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.45 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.529), 0.25 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.227), 0.4 mol of PTMG-1000 (molar ratio of diacid monomer to diol monomer is 1:1.22), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.00042:1) are added to the reaction vessel and mixed.

[0080] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0081] Add 0.9 mol of dimethyl terephthalate, 0.45 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.529), 0.25 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.227), and 0.4 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.22) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.00042:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0082] The intrinsic viscosity of the elastomer in Example 3 was 1.13 dL / g, and the number-average molecular weight was 1.03 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.05 × 10⁻⁶ g / mol 4 g / mol, with no crystallization temperature or melting temperature, no obvious peaks were observed in the test curve, the tensile strength of the sample was 21.54 MPa, the tensile modulus was 110.34 MPa, the elongation at break was 963.8%, and the light transmittance was 93%.

[0083] Example 4:

[0084] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of PTMG-500 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) are added to the reaction vessel and mixed.

[0085] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0086] Add 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), and 0.1 mol of... PTMG-500 (molar ratio of diacid monomer to diol monomer of 1:1.36) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0087] The intrinsic viscosity of the elastomer in Example 4 was 1.47 dL / g, and the number-average molecular weight was 1.93 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 6.13 × 10 4 g / mol, crystallization temperature 128.8℃, melting temperature 183.2℃, tensile strength of the sample 33.58MPa, tensile modulus 214.13MPa, elongation at break 429.3%, and light transmittance 53%.

[0088] Example 5:

[0089] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of PTMG-2000 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) are added to the reaction vessel and mixed.

[0090] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0091] Add 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), and 0.1 mol of... PTMG-2000 (molar ratio of diacid monomer to diol monomer of 1:1.36) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0092] In Example 5, the intrinsic viscosity of the elastomer was 1.35 dL / g, and the number-average molecular weight was 1.26 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.01×10 4 g / mol, crystallization temperature 103.5℃, melting temperature 143.7℃, tensile strength of the sample 19.86MPa, tensile modulus 160.28MPa, elongation at break 715.1%, and light transmittance 83%.

[0093] Example 6:

[0094] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.8 mol of dimethyl terephthalate, 0.1 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of PTMG-1000 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) are added to the reaction vessel and mixed.

[0095] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0096] Add 0.8 mol of dimethyl terephthalate, 0.1 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.36) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0097] The intrinsic viscosity of the elastomer in Example 6 was 1.24 dL / g, and the number-average molecular weight was 1.18 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.61 × 10⁻⁶ g / mol. 4 The sample has a tensile strength of 25.53 MPa, a tensile modulus of 175.86 MPa, an elongation at break of 618.6%, and a light transmittance of 75%, with a crystallization temperature and melting temperature of g / mol.

[0098] Example 7:

[0099] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.7 mol of dimethyl terephthalate, 0.2 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of PTMG-1000 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) are added to the reaction vessel and mixed.

[0100] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0101] Add 0.7 mol of dimethyl terephthalate, 0.2 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (the molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.36) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0102] The intrinsic viscosity of the elastomer in Example 7 was 1.17 dL / g, and the number-average molecular weight was 1.11 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.31 × 10⁻⁶ g / mol. 4 The sample has a tensile strength of 19.31 MPa, a tensile modulus of 113.54 MPa, an elongation at break of 663.3%, and a light transmittance of 83%, with a crystallization temperature and melting temperature of g / mol.

[0103] Example 8:

[0104] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.5 mol of dimethyl terephthalate, 0.4 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), 0.1 mol of PTMG-1000 (molar ratio of diacid monomer to diol monomer is 1:1.36), and 0.00084 mol of tetrabutyl titanate (molar ratio of catalyst to raw material monomer is 0.000396:1) are added to the reaction vessel and mixed.

[0105] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0106] Add 0.5 mol of dimethyl terephthalate, 0.4 mol of dimethyl 1,4-cyclohexanedicarboxylate, 0.72 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.878), 0.4 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.328), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.36) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000396:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0107] The intrinsic viscosity of the elastomer in Example 8 was 1.38 dL / g, and the number-average molecular weight was 1.37 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.11 × 10⁻⁶ g / mol. 4 g / mol, crystallization temperature 109.8℃, melting temperature 173.3℃, ​​tensile strength of the sample 26.28MPa, tensile modulus 163.29MPa, elongation at break 529.3%, and light transmittance 92%.

[0108] Example 9:

[0109] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 1.08 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.915), 0.2 mol of 1,4-cyclohexanediethanol (the molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.478), 0.1 mol of PTMG-1000 (the molar ratio of diacid monomer to diol monomer is 1:2.51), and 0.00084 mol of tetrabutyl titanate (the molar ratio of catalyst to raw material monomer is 0.000266:1) are added to the reaction vessel and mixed.

[0110] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0111] Add 0.9 mol of dimethyl terephthalate, 1.08 mol of 1,4-butanediol (molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.915), 0.2 mol of 1,4-cyclohexanediethanol (molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.478), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:2.51) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000266:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0112] The intrinsic viscosity of the elastomer in Example 9 was 1.37 dL / g, and the number-average molecular weight was 1.54 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.23 × 10 4 g / mol, crystallization temperature 133.7℃, melting temperature 183.7℃, tensile strength of the sample 27.34MPa, tensile modulus 210.67MPa, elongation at break 445.6%, and light transmittance 54%.

[0113] Example 10:

[0114] A highly transparent thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.36 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.783), 0.6 mol of 1,4-cyclohexanediethanol (the molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.566), 0.1 mol of PTMG-1000 (the molar ratio of diacid monomer to diol monomer is 1:1.18), and 0.00084 mol of tetrabutyl titanate (the molar ratio of catalyst to raw material monomer is 0.000429:1) are added to the reaction vessel and mixed.

[0115] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0116] Add 0.9 mol of dimethyl terephthalate, 0.36 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.783), 0.6 mol of 1,4-cyclohexanediethanol (the molar ratio of cyclic diol to the sum of aliphatic diol, polyether diol and cyclic diol is 0.566), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.18) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000429:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain a highly transparent thermoplastic polyester elastomer, which is the final product.

[0117] The intrinsic viscosity of the elastomer in Example 10 was 1.32 dL / g, and the number-average molecular weight was 1.13 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.65 × 10 4 The sample has a tensile strength of 24.43 MPa, a tensile modulus of 123.94 MPa, an elongation at break of 494.5%, and a light transmittance of 87%, with a crystallization temperature and melting temperature of g / mol.

[0118] Comparative Example 1:

[0119] A thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol, 0.72 mol of ethylene glycol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), 0.1 mol of PTMG-1000 (the molar ratio of diacid monomer to diol monomer is 1:1.71) and 0.00084 mol of tetrabutyl titanate (the molar ratio of catalyst to raw material monomer is 0.000344:1) are added to the reaction vessel and mixed.

[0120] The specific steps for preparing the above-mentioned thermoplastic polyester elastomer are as follows:

[0121] Add 0.9 mol of dimethyl terephthalate, 0.72 mol of 1,4-butanediol, 0.72 mol of ethylene glycol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.71) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000344:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain thermoplastic polyester elastomer, which is the final product.

[0122] The intrinsic viscosity of the elastomer in Comparative Example 1 was 1.04 dL / g, and the number-average molecular weight was 1.02 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.25 × 10 4 The sample has a concentration of g / mol, a crystallization temperature of 151℃, a melting temperature of 213℃, a tensile strength of 23.54 MPa, a tensile modulus of 121.4 MPa, an elongation at break of 554.5%, and a light transmittance of 41%.

[0123] Comparative Example 2:

[0124] A thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 0.2 mol of dimethyl isophthalate, 1.44 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), 0.1 mol of PTMG-1000 (the molar ratio of diacid monomer to diol monomer is 1:1.4) and 0.00084 mol of tetrabutyl titanate (the molar ratio of catalyst to raw material monomer is 0.000318:1) are added to the reaction vessel and mixed.

[0125] The specific steps for preparing the above-mentioned thermoplastic polyester elastomer are as follows:

[0126] Add 0.9 mol of dimethyl terephthalate, 0.2 mol of dimethyl isophthalate, 1.44 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.4) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000318:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 hour to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 hour. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 hours. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 hours to obtain thermoplastic polyester elastomer, which is the final product.

[0127] The intrinsic viscosity of the elastomer in Comparative Example 2 was 1.43 dL / g, and the number-average molecular weight was 2.24 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 4.94 × 10 4 g / mol, crystallization temperature 146℃, melting temperature 167.3℃, tensile strength of the sample 31.57MPa, tensile modulus 60.2MPa, elongation at break 1277.9%, and light transmittance 54%.

[0128] Comparative Example 3:

[0129] A thermoplastic polyester elastomer is basically the same as in Example 1, except that in step S1, 0.9 mol of dimethyl terephthalate, 1.44 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), 0.1 mol of PTMG-1000 (the molar ratio of diacid monomer to diol monomer is 1:1.71) and 0.00084 mol of tetrabutyl titanate (the molar ratio of catalyst to raw material monomer is 0.000344:1) are added to the reaction vessel and mixed.

[0130] The specific steps for preparing the above-mentioned highly transparent thermoplastic polyester elastomer are as follows:

[0131] Add 0.9 mol of dimethyl terephthalate, 1.44 mol of 1,4-butanediol (the molar ratio of aliphatic diol to the sum of aliphatic diol and polyether diol is 0.935), and 0.1 mol of... PTMG-1000 (molar ratio of diacid monomer to diol monomer of 1:1.71) and 0.00084 mol tetrabutyl titanate (molar ratio of catalyst to raw material monomer of 0.000344:1) were added to a reactor and mixed. Under nitrogen protection, the temperature was raised to 190℃ and the rotation speed was set to 200 r / min for esterification (ester exchange) reaction for 1 h to obtain oligomers. The oligomers were pre-polymerized at 220℃ and 4 kPa for 1 h. The methanol generated by the pre-polymerization was collected in the condensate and reached more than 90% of the theoretical methanol content. The temperature was raised to 270℃ and under a high vacuum of 100 Pa for final polymerization for 1.5 h. During the process, the torque change was observed and the rotation speed was gradually reduced. After the rotation speed was reduced to the minimum and the torque reached the maximum, the product was discharged. The product was then dried at 30℃ and under a vacuum of 300 Pa for 12 h to obtain thermoplastic polyester elastomer, which is the final product.

[0132] The intrinsic viscosity of the elastomer in Comparative Example 3 was 1.37 dL / g, and the number-average molecular weight was 2.58 × 10⁻⁶. 4 g / mol, weight-average molecular weight is 5.75 × 10 4 The sample has a g / mol content, a crystallization temperature of 149.9℃, a melting temperature of 202.6℃, a tensile strength of 34.1MPa, a tensile modulus of 116.7MPa, an elongation at break of 1125.7%, and a light transmittance of 14%.

[0133] The raw material information for the above-mentioned thermoplastic polyester elastomers is shown in Table 1.

[0134] Table 1. Raw material information of thermoplastic polyester elastomers in the examples and comparative examples.

[0135]

[0136] The performance information of the above thermoplastic polyester elastomers is shown in Table 2.

[0137] Table 2 shows the performance information of the thermoplastic polyester elastomers in the examples and comparative examples.

[0138]

[0139] As shown in Tables 1 and 2, it can be seen from Examples 1 to 3 that by changing the ratio of aliphatic diol, cyclic diol and polyether diol, the ratio of soft and hard segments and the degree of transparency of the elastomer can be adjusted, and a highly transparent thermoplastic polyester elastomer with a high molecular weight and high light transmittance can be prepared to meet different hardness and elasticity requirements.

[0140] As can be seen from Examples 1, 4 and 5, by changing the molecular weight of polyether diol, different highly transparent thermoplastic polyester elastomers can be obtained, thereby affecting the tensile strength, elongation at break, light transmittance and other properties of the elastomer.

[0141] As can be seen from Examples 1, 6 to 10, by changing the type and ratio of cyclic dicarboxylic acid or its ester, aliphatic diol and cyclic diol, highly transparent thermoplastic polyester elastomers with different light transmittance and tensile properties can be obtained. The addition of cyclic diol disrupts the regular hard segment crystallization, resulting in a significant change in the crystallization behavior of the elastomer, thereby changing the mechanical properties and light transmittance of the elastomer.

[0142] As can be seen from Example 1 and Comparative Examples 1 to 3, the addition of cyclic diols can significantly disrupt the hard segment crystals of the elastomer, thus preparing a highly transparent thermoplastic polyester elastomer with high light transmittance.

[0143] The performance test results of the examples and comparative examples show that the high transparency thermoplastic polyester elastomer prepared by the present invention can be controlled in terms of its mechanical properties, hardness, thermal behavior and light transmittance by designing the molecular structure and adjusting the molecular weight and the ratio of soft and hard segments, thereby meeting the application requirements.

[0144] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A highly transparent thermoplastic polyester elastomer, characterized in that, The chemical structural formula of the unit cell of this elastomer is as follows: Wherein, a, b, and c are all non-zero integers, a:(a+b) is 0.1 to 0.95, c:(a+b+c) is 0.05 to 0.8, R1 is an alkyl group with 2 to 18 carbon atoms, R2 is an alicyclic, aromatic, or furan ring, wherein the aromatic ring is selected from one or more of benzene ring, biphenyl ring, and naphthalene ring, R3 is a polyether or polyester, and R4 is an aliphatic saturated ring.

2. A method for preparing a highly transparent thermoplastic polyester elastomer as described in claim 1, characterized in that, The method includes the following steps: The raw material monomers and catalyst are mixed. The raw material monomers include diacid monomers and diol monomers. The diacid monomers include cyclic diacids or their esterifications. The diol monomers include aliphatic diols, cyclic diols and polyether diols. The esterification reaction is carried out under a protective gas atmosphere to obtain oligomers. The oligomers are pre-condensed and then final-condensed under vacuum conditions to obtain a highly transparent thermoplastic polyester elastomer.

3. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The cyclic dicarboxylic acid or its esterified form is selected from one or more of terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, phthalic acid, dimethyl phthalate, 1,4-cyclohexanedicarboxylic acid, and dimethyl 1,4-cyclohexanedicarboxylic acid.

4. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The aliphatic diol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol, and neopentanediol.

5. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The cyclic diol is selected from one or more of 1,4-cyclohexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and isosorbide.

6. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The polyether diol is selected from one or more of polyethylene glycol, polypropylene glycol, and polytetramethylene ether diol, and the number average molecular weight of the polyether diol is 200 to 2000.

7. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The molar ratio of the dicarboxylic acid monomer to the diol monomer is 1:(1.05-3).

8. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The catalyst is selected from one or more catalysts with 1 to 12 carbon atoms selected from organoaluminum compounds, organotin compounds, and titanates.

9. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The molar ratio of the catalyst to the raw material monomer is (0.0002~0.005):

1.

10. The method for preparing a highly transparent thermoplastic polyester elastomer according to claim 2, characterized in that, The esterification reaction was carried out at a temperature of 150–280°C, a rotation speed of 100–300 r / min, and a time of 0.5–4 h. The pre-polymerization temperature is 180–280℃, the pressure is 3–10 kPa, and the time is 0.5–2 h. The final polycondensation temperature is 180–280°C, the vacuum degree is 50–300 Pa, and the time is 1–8 h.

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