Thermoplastic polyester elastomer as well as preparation method and application thereof

Abstract

The invention provides a thermoplastic polyester elastomer as well as a preparation method and application thereof. The thermoplastic polyester elastomer comprises aromatic dibasic acid residues and aliphatic polyol residues, on the basis that the total molar weight of the aliphatic polyol residues is 100 mol%, the aliphatic polyol residues comprise 66 to 95 mol% of micromolecular diol residues, 2 to 24 mol% of polymer polyol residues and 1.5 to 10 mol% of third polyol residues; the third polyhydric alcohol residues comprise residues derived from a benzotriazole compound and residues derived from a tetramethyl piperidine compound. The thermoplastic polyester elastomer is good in light aging resistance, the surface of a workpiece is not separated out in the processing process and after the thermoplastic polyester elastomer is placed for a long time, and the requirement of automobile interiors for color change of light-color materials after light aging is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a thermoplastic polyester elastomer and its preparation method and application. Background Art

[0002] Thermoplastic polyester elastomer materials have excellent mechanical properties, chemical solvent resistance, fatigue resistance, etc., and can be directly injection molded without vulcanization. They have been widely used in fields such as automotive intake hoses, drive system dust covers, sports shoe soles, and railway gaskets.

[0003] Among them, interior parts such as automotive soft skins are generally made of materials such as polyvinyl chloride (PVC) and thermoplastic polyolefin (TPO) through processes such as sheet extrusion - thermoforming and rotational molding. However, materials such as PVC and TPO have high costs and high process energy consumption, and the surface patterns of the obtained interior parts are not delicate. The injection molding process has advantages such as short molding cycle, low cost, adjustable and delicate surface patterns, and long mold life, and can be used to produce such parts.

[0004] Currently, there have been studies on using materials such as styrenic thermoplastic elastomers (TPS) and dynamically vulcanized thermoplastic elastomers (TPV) through the injection molding process for the production of automotive soft interior skins. However, materials such as TPS and TPV have relatively low surface energy, and processes such as flame treatment, plasma treatment, and spraying high - cost primer coatings are required to increase the material polarity to achieve the adhesion between the skin layer and the polyurethane (PU) foam layer. This leads to problems such as complex processes, high part costs, and decreased production yield.

[0005] Thermoplastic polyester elastomers have high surface energy and can achieve advantages such as direct adhesion to the PU foam layer without surface treatment. However, thermoplastic polyester elastomers are prone to cracking under light conditions. To improve the light stability of thermoplastic elastomers, generally a large amount of carbon black, titanium dioxide, etc. are added, but adding materials such as carbon black makes it impossible to produce light - colored parts; or ultraviolet light absorbers, light stabilizers, etc. are blended, but the added ultraviolet light absorbers, light stabilizers, etc. are prone to exudation and cannot meet the requirements of automotive OEMs for the color change of light - colored materials after light aging.

[0006] Therefore, developing a thermoplastic polyester elastomer with good light aging resistance, no risk of exudation, and meeting the requirements of automotive interiors for the color change of light - colored materials after light aging is an urgent problem in this field. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a thermoplastic polyester elastomer and its preparation method and application. The thermoplastic polyester elastomer has good light aging resistance, and there is no exudation on the surface of the parts during the processing and long - term storage, meeting the requirements of automotive interiors for the color change of light - colored materials after light aging.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a thermoplastic polyester elastomer, which comprises aromatic dicarboxylic acid residues and aliphatic polyol residues; based on the total molar amount of aliphatic polyol residues being 100 mol%, the aliphatic polyol residues comprise 66 - 95 mol% of small molecule diol residues, 2 - 24 mol% of polymer polyol residues, and 1.5 - 10 mol% of a third polyol residue; the third polyol residue includes residues derived from benzotriazole compounds and residues derived from tetramethylpiperidine compounds.

[0010] In the present invention, the benzotriazole structure has strong absorption of ultraviolet light with a wavelength of 200 - 400 nm, which can avoid the damage of ultraviolet light to the resin matrix; the tetramethylpiperidine group can decompose the free radicals generated during the photoaging process of the material, cut off the free radical chain reaction, thereby weakening the damage of light to the resin; through the compounding of benzotriazole compounds and tetramethylpiperidine compounds, and introducing the benzotriazole structure and tetramethylpiperidine group into the molecular structure of the polyester, not only can the light aging resistance of the thermoplastic polyester elastomer be improved, but also a high content of active groups can be achieved without the risk of precipitation.

[0011] In the present invention, the molar ratio of the aromatic dicarboxylic acid residues to the aliphatic polyol residues is (0.9 - 1.1):1.

[0012] In the present invention, 66 - 95 mol% of small molecule diol residues can be, for example, 66 mol%, 68 mol%, 70 mol%, 72 mol%, 74 mol%, 76 mol%, 78 mol%, 80 mol%, 82 mol%, 84 mol%, 86 mol%, 88 mol%, 90 mol%, 92 mol%, 94 mol%, 95 mol% or the range between any of the above values.

[0013] In the present invention, 2 - 24 mol% of polymer polyol residues can be, for example, 2 mol%, 4 mol%, 6 mol%, 8 mol%, 10 mol%, 12 mol%, 14 mol%, 16 mol%, 18 mol%, 20 mol%, 22 mol%, 24 mol% or the range between any of the above values.

[0014] In the present invention, the 1.5 to 10 mol% of the third polyol residue can be, for example, 1.5 mol%, 1.6 mol%, 1.8 mol%, 2 mol%, 2.2 mol%, 2.4 mol%, 2.5 mol%, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, 8.5 mol%, 9 mol%, 9.5 mol%, 10 mol% or a range between any of the above values.

[0015] It should be noted that the "residue" in the present invention refers to the organic structure introduced into the thermoplastic polyester elastomer through a polymerization reaction by the relevant monomer, that is, the structural unit derived from the relevant monomer; for example, the aromatic dicarboxylic acid residue refers to the structural unit derived from the aromatic dicarboxylic acid.

[0016] Preferably, based on the total molar amount of the aliphatic polyol residue being 100 mol%, the molar percentage content of the residue derived from the benzotriazole compound in the aliphatic polyol residue is 0.05 to 2.1 mol%, and can be, for example, 0.05 mol%, 0.08 mol%, 0.1 mol%, 0.2 mol%, 0.4 mol%, 0.6 mol%, 0.8 mol%, 1 mol%, 1.2 mol%, 1.4 mol%, 1.6 mol%, 1.8 mol%, 2 mol% or a range between any of the above values; more preferably 0.4 to 1.5 mol%.

[0017] Preferably, the number of hydroxyl groups in the molecular structure of the benzotriazole compound is ≥2, and can be, for example, 2, 3, 4, 5 or a range between any of the above values; more preferably, the number of hydroxyl groups in the molecular structure of the benzotriazole compound is 3.

[0018] Preferably, the benzotriazole compound has the structure shown in Formula I.

[0019]

[0020] In Formula I, R1 is selected from any one of H, halogen, or a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms; R2, R3, R4, and R5 are each independently selected from H, hydroxyl group, a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms in which at least one H is substituted by a hydroxyl group, or any one of them; and the total number of hydroxyl groups in R2, R3, R4, and R5 is ≥2, and can be, for example, 2, 3, 4, 5, 6, etc.; more preferably, the total number of hydroxyl groups in R2, R3, R4, and R5 is 2; R 11 、R 12 、R 13Each independently selected from any one of H, hydroxyl group, C1-C6 straight-chain or branched-chain alkyl group or C1-C6 straight-chain or branched-chain alkyl group in which at least one H is substituted by a hydroxyl group; m and n are each independently selected from integers of 0-4, for example, can be 0, 1, 2, 3, 4; "*" represents the connection site.

[0021] In the present invention, the aforementioned C1-C6 straight-chain or branched-chain alkyl group refers to a straight-chain or branched-chain alkyl group including 1-6 carbon atoms (for example, can be 1, 2, 3, 4, 5, 6); exemplarily includes but is not limited to methyl, ethyl, isopropyl, n-propyl, n-butyl, tert-butyl, etc.; the halogen includes any one of F, Cl, Br, I; if there is the same expression below, it means the same meaning and scope.

[0022] Preferably, the benzotriazole compound includes At least one of 3-(2H-benzotriazol-2-yl)-4-hydroxybenzeneethanol or 2-(2,4-dihydroxyphenyl)-2H-benzotriazole.

[0023] Based on the total molar amount of aliphatic polyol residues being 100 mol%, the molar percentage content of the residues derived from tetramethylpiperidine compounds in the aliphatic polyol residues is 0.5-9.5 mol%, for example, can be 0.5 mol%, 1 mol%, 1.5 mol%, 2 mol%, 2.5 mol%, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, 8.5 mol%, 9 mol%, 9.5 mol% or the range between any of the above values; more preferably 1.5-7.5 mol%.

[0024] Preferably, the tetramethylpiperidine compound has the structure shown in Formula II.

[0025]

[0026] In Formula II, R1 and R2 are each independently selected from any one of H, hydroxyl group, C1-C6 straight-chain or branched-chain alkyl group or C1-C6 straight-chain or branched-chain alkyl group in which at least one H is substituted by a hydroxyl group; and the total number of hydroxyl groups in R1 and R2 ≥ 2, for example, can be 2, 3, 4, 5, 6, etc.; more preferably, the total number of hydroxyl groups in R1 and R2 is 2.

[0027] Preferably, R1 is selected from -OH; R2 is selected from -CH2CH2OH.

[0028] Preferably, the aromatic dicarboxylic acid residue includes at least one of terephthalic acid residue, phthalic acid residue or isophthalic acid residue; more preferably, it includes at least terephthalic acid residue.

[0029] In the present invention, the molar percentage content of terephthalic acid residue in the aromatic dicarboxylic acid residue ≥ 50%, more preferably ≥ 70%.

[0030] Preferably, the small molecule diol residue includes C2-C6 aliphatic diol residues, such as C2, C3, C4, C5, C6 aliphatic diol residues.

[0031] Preferably, the small molecule diol residue includes at least one of ethylene glycol residue, 1,3-propanediol residue, 1,4-butanediol residue, 1,5-pentanediol residue or 1,6-hexanediol residue.

[0032] Preferably, the polymer polyol residue includes a polyether polyol residue.

[0033] Preferably, the polyether polyol residue includes a polytetrahydrofuran ether diol residue.

[0034] Preferably, the number average molecular weight of the polymer polyol residue is 1000-3200, such as 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200, 2400, 2600, 2800, 3000, 3200 or the range between any of the above values.

[0035] In the present invention, the number average molecular weight of the polymer polyol residue is determined by the number average molecular weight of the raw material polymer polyol. The number average molecular weight of the polymer polyol can be measured by a gel permeation chromatograph, and the instrument model is: Waters ACQUITY APC; tetrahydrofuran is selected as the mobile phase, and the sample concentration is 1mg / mL.

[0036] In the present invention, the viscosity of the dilute solution (mass concentration of 0.005g / mL) of the thermoplastic polyester elastomer is 1.0-2.0 dL / g; the test method for the viscosity includes: weighing 0.125g of the thermoplastic polyester elastomer, dissolving it in 25mL of a mixed solvent of phenol / o-dichlorobenzene (mass ratio of 60 / 40) after pulverization, filtering through a sintered glass funnel, and measuring the efflux time t1 with a capillary viscometer. The efflux time of the blank solvent is t0, and the test temperature is 25°C. Calculate the viscosity of the dilute solution of the thermoplastic polyester elastomer according to the following formula.

[0037]

[0038] Wherein: [η]: is the dilute solution viscosity of the thermoplastic polyester elastomer; t1: is the time for the thermoplastic polyester elastomer solution to flow through the capillary viscometer, in s; t0: is the time for the solvent to flow through the capillary viscometer, in s; c: is the viscosity of the thermoplastic polyester elastomer solution, in g / 100mL.

[0039] In a second aspect, the present invention provides a method for preparing the thermoplastic polyester elastomer described in the first aspect, and the preparation method includes the following steps:

[0040] Mix an aromatic dicarboxylic acid, a small molecule diol, a polymer polyol, and a third polyol, and react to obtain the thermoplastic polyester elastomer.

[0041] Preferably, the raw materials for mixing further include a catalyst and / or an antioxidant.

[0042] In the present invention, the mass of the catalyst is 0.01 to 0.1% of the total weight of the preparation raw materials (i.e., the total mass of the aromatic dicarboxylic acid, the small molecule diol, the polymer polyol, and the third polyol), and for example, it can be 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, or the range between any of the above values; the catalyst includes but is not limited to titanate compounds; the mass of the antioxidant is 0.02 to 0.2% of the total weight of the preparation raw materials, and for example, it can be 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, or the range between any of the above values; the antioxidant includes but is not limited to hindered phenol antioxidants (such as antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 1019, antioxidant 330, antioxidant 3114, antioxidant 1790, antioxidant 3125, antioxidant 245, antioxidant BHT, etc.), phosphite antioxidants (such as antioxidant 168, antioxidant PEP-36, antioxidant 626, antioxidant 686, antioxidant P-EPQ), etc.

[0043] Preferably, the reaction includes: S1: React the aromatic dicarboxylic acid with the small molecule diol to obtain product A; S2: React the product A with the polymer polyol and the third polyol to obtain product B; S3: Perform a polycondensation reaction on product B to obtain the thermoplastic polyester elastomer.

[0044] Preferably, the temperature of the reaction in step S1 is 190 to 230 °C, and for example, it can be 190 °C, 195 °C, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, 225 °C, 230 °C, or the range between any of the above values; the reaction time is 0.5 to 3 h, and for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, or the range between any of the above values.

[0045] Preferably, the temperature of the reaction in step S2 is 190 - 230°C, for example, it can be 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C or the range between any of the above values; the reaction time is 0.5 - 3 h, for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h or the range between any of the above values.

[0046] Preferably, the temperature of the polycondensation reaction in step S3 is 235 - 255°C, for example, it can be 235°C, 240°C, 245°C, 250°C, 255°C or the range between any of the above values; the reaction pressure ≤ 100 Pa, for example, it can be 10 Pa, 20 Pa, 40 Pa, 60 Pa, 80 Pa, 100 Pa or the range between any of the above values; the reaction time is 2 - 4 h, for example, it can be 2 h, 2.5 h, 3 h, 3.5 h, 4 h or the range between any of the above values.

[0047] In the present invention, the reaction in step S1 is carried out in the presence of a protective atmosphere; the protective atmosphere includes but is not limited to nitrogen; the raw materials for the reaction in step S1 further include a catalyst and an antioxidant; the raw materials for the reaction in step S2 further include a catalyst.

[0048] In the present invention, the method for preparing the thermoplastic polyester elastomer includes:

[0049] In the presence of a protective atmosphere, an aromatic dicarboxylic acid, a small molecule diol and 40 - 60% of the formulated amount of a catalyst and an antioxidant are mixed, and the reaction is carried out at 190 - 230°C for 0.5 - 3 h; polymer polyol, a third polyol and the remaining catalyst are added thereto and the reaction is continued at 190 - 230°C for 0.5 - 3 h, then the temperature is raised to 235 - 255°C, the system pressure is reduced to below 100 Pa within 30 min, and the reaction is continued for 2 - 4 h; the stirring is stopped, high-purity nitrogen is charged into the system, and the material is extruded from the die orifice, cooled by water and pelletized to obtain the thermoplastic polyester elastomer.

[0050] In a third aspect, the present invention provides a polyester composition, and the polyester composition includes the thermoplastic polyester elastomer described in the first aspect.

[0051] Preferably, the polyester composition further includes at least one of a filler, an auxiliary agent or a pigment.

[0052] In the present invention, the mass percentage content of the thermoplastic polyester elastomer in the polyester composition ≥ 30%, preferably ≥ 40%, further preferably ≥ 50%, more preferably ≥ 60%.

[0053] In the present invention, various fillers, additives, pigments, etc. can be added according to actual needs; exemplarily, the fillers include but are not limited to mineral powder, glass fiber, carbon fiber, etc.; the additives include but are not limited to flame retardants (such as melamine cyanurate, melamine polyphosphate, hypophosphite, aluminum hydroxide, magnesium hydroxide, phosphate ester flame retardants, etc.), antioxidants (such as antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 168, antioxidant 626, etc.), ultraviolet light absorbers (such as UV-P, UV-O, UV-9, UV-531, UV-1164, UV-1577, UV-1600, UV-3030, UV-329, UV-326, UV-360, UV-328, etc.), light stabilizers (such as light stabilizer 944, light stabilizer 622, light stabilizer 770, light stabilizer 3853, light stabilizer 3529, light stabilizer 3346, light stabilizer LA-63, light stabilizer UV-123, light stabilizer 119, light stabilizer 3030, light stabilizer 2020, light stabilizer 5050, light stabilizer 144, light stabilizer UV-3034, light stabilizer 3150, light stabilizer 3159, etc.), etc.

[0054] In the present invention, the preparation method of the polyester composition includes: mixing each component uniformly and then extruding to obtain the polyester composition; the temperature of the extrusion is 180 - 230 °C; the extrusion is carried out in a twin-screw extruder; the length-diameter ratio of the twin-screw extruder is 36 - 60:1, and the residence time of the material in the screw is 40 - 60 s.

[0055] In the fourth aspect, the present invention provides an automotive interior trim, and the material of the automotive interior trim includes the thermoplastic polyester elastomer described in the first aspect or the polyester composition described in the third aspect.

[0056] The numerical ranges described in the present invention not only include the above-listed point values, but also include any point values between the above numerical ranges not listed. Due to space limitations and for the sake of brevity, the specific point values included in the ranges are not exhaustively listed in the present invention.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0058] The thermoplastic polyester elastomer provided by the present invention introduces a benzotriazole structure and a tetramethylpiperidine group into the molecular structure of the polyester, and through the compounding of the two, it can not only improve the light aging resistance of the thermoplastic polyester elastomer, but also there is no precipitation on the surface of the parts during the processing process and after long-term placement, meeting the requirements of the automotive interior trim for the color change of light-colored materials after light aging. Detailed Embodiments

[0059] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0060] The materials used in the present invention can be obtained by purchasing commercially or prepared by conventional methods; unless otherwise specified, the materials used in all examples and comparative examples of the present invention are as follows:

[0061] Terephthalic acid: commercially available industrial grade purified terephthalic acid, produced by INEOS CHEMICAL.

[0062] Isophthalic acid: commercially available industrial grade isophthalic acid, produced by LOTTE CHEMICAL.

[0063] 1,4-Butanediol: commercially available industrial grade 1,4-butanediol, produced by Xinjiang Blue Mountain Tunhe.

[0064] 1,6-Hexanediol: purchased from Energy Chemical.

[0065] Polytetrahydrofuran ether diol (PTMG): PTMGs with different degrees of polymerization are produced by Korea PTG.

[0066] The third polyol:

[0067] Benzotriazole compound 1: Chiguard R-455 from Qitech.

[0068] Benzotriazole compound 2: 3-(2H-benzotriazol-2-yl)-4-hydroxy phenethyl alcohol, commercially available.

[0069] Tetramethylpiperidine compound 1: Self-made, and the specific preparation method refers to the following literature: Cui Jialing, Zhang Shengjian, Luo Shu, Li Ting, Zhang Hong, "Zhejiang Chemical Industry", 2006V37, I1, p1-2.

[0070] 2,4-Dihydroxybenzophenone, sourced from commercial.

[0071] Examples 1 to 13, Comparative Examples 1 to 6

[0072] Examples 1 to 13 and Comparative Examples 1 to 6 respectively provide a thermoplastic polyester elastomer, which comprises aromatic dicarboxylic acid residues and aliphatic polyol residues; the molar ratio of the aromatic dicarboxylic acid residues to the aliphatic polyol residues is 1:1; the content composition of the aromatic dicarboxylic acid residues (based on the total molar content of the aromatic dicarboxylic acid residues being 100 mol%) and the composition of the aliphatic polyol residues (based on the total molar content of the aliphatic polyol residues being 100 mol%) are shown in Tables 1 to 3; wherein, " / " indicates that there is no such residue in the thermoplastic polyester elastomer.

[0073] Among them, the content of each residue in the thermoplastic polyester elastomer is determined by 1 1H NMR. The thermoplastic polyester elastomer is dissolved in CDCl3 / CF3COOD (volume ratio about 9 / 1), and tested on a Bruker 400 MHz nuclear magnetic resonance spectrometer. The molar content of each residue is calculated according to the integral area. Taking terephthalic acid, isophthalic acid, 1,4-butanediol, PTMG, benzotriazole compound 1, and tetramethylpiperidine compound 1 as examples, the content of each residue is calculated according to the following formula.

[0074] Terephthalic acid:

[0075] Isophthalic acid:

[0076] 1,4-Butanediol

[0077]

[0078] PTMG

[0079]

[0080] Benzotriazole compound 1

[0081]

[0082] Tetramethylpiperidine compound 1

[0083]

[0084] Wherein: S 8.1 (terephthalic acid), S 7.59 (isophthalic acid), S 4.5 (1,4-butanediol), S 3.6 (PTMG), S 2.0 (1,4-butanediol), S 1.7 (PTMG)S 1.4 (benzotriazole compound 1), S 1.2 (tetramethylpiperidine compound 1) are respectively1 The integral areas of the absorption peaks at 8.1 ppm, 7.59 ppm, 4.5 ppm, 3.6 ppm, 2.0 ppm, 1.7 ppm, 1.4 ppm, and 1.2 ppm in the HNMR spectrum.

[0085] The preparation method of the thermoplastic polyester elastomer includes:

[0086] Mix an aromatic dicarboxylic acid, a small molecule diol, a catalyst (tetrabutyl titanate, with a mass of 0.025% of the total mass of the aromatic dicarboxylic acid, small molecule diol, polymer polyol, and third polyol) and antioxidant 1010 (with a mass of 0.05% of the total mass of the aromatic dicarboxylic acid, small molecule diol, polymer polyol, and third polyol), and react at 210 °C for 1.5 h; add a polymer polyol, a third polyol, and a catalyst (tetrabutyl titanate, with a mass of 0.025% of the total mass of the aromatic dicarboxylic acid, small molecule diol, polymer polyol, and third polyol) and continue to react at 210 °C for 1.5 h, then raise the temperature to 245 °C, reduce the system pressure to below 100 Pa within 30 min, and continue to react for 3 h; stop stirring, fill the system with high-purity nitrogen, extrude the material from the die orifice, cool it with water, pelletize it, and obtain the thermoplastic polyester elastomer.

[0087] Table 1

[0088]

[0089]

[0090] Table 2

[0091]

[0092] Table 3

[0093]

[0094]

[0095] Application Example

[0096] A polyester composition, in parts by weight, the polyester composition includes 70 parts of a thermoplastic polyester elastomer and 30 parts of a flame retardant Exolit OP 1230 (produced by Clariant); the thermoplastic polyester elastomers are respectively the thermoplastic polyester elastomers provided in Examples 1 to 13 and Comparative Examples 1 to 6. The preparation method of the polyester composition includes: mixing each component evenly, feeding it into a twin-screw extruder through a loss-in-weight metering scale, extruding at 210 °C, cooling, pelletizing, and drying to obtain the polyester composition. Among them, the ratio of the length to the diameter of the twin-screw extruder used is 44:1, and the residence time of the material in the screw is 50 s.

[0097] Among them, benzotriazole compound 1 (with a mass of 1 wt% of the thermoplastic polyester elastomer) and tetramethylpiperidine compound 1 (with a mass of 2.5 wt% of the thermoplastic polyester elastomer) were directly mixed and extruded with 70 parts of thermoplastic polyester elastomer (the composition of the thermoplastic polyester elastomer is only different from that of Example 1 in that there is no structural unit derived from benzotriazole compound 1 and tetramethylpiperidine compound 1 in the molecular structure, and the others are the same as those in Example 1) and 30 parts of flame retardant as a control group.

[0098] Performance testing

[0099] (1) Light aging resistance: The polyester composition was injection-molded into 2-mm sheet specimens and placed in a xenon lamp aging chamber. The operating conditions of the aging chamber were as follows: window glass filter, irradiance of 0.55 W / (m 2 ·nm) @ 340 nm, blackboard temperature of 89 °C, chamber temperature of 60 °C, relative humidity of 50%, and continuous light exposure for 500 h. The color difference was measured using an integrating sphere spectrophotometer, and the gray scale rating was tested according to ISO 105-A2;

[0100] (2) Exudation resistance: The resin composition was injection-molded into sheet specimens of 100 × 100 × 2 mm and placed for 6 months at a temperature of 23 °C and a humidity of 50%. A Leica optical microscope was used to observe whether there was exudation on the surface of the specimens; after the thermoplastic polyester elastomer was dried, 100 consecutive molds were injection-molded, and the surface of the mold was observed for exudation.

[0101] The specific test results are shown in Table 4.

[0102] Table 4

[0103]

[0104] As can be seen from Table 4, for the thermoplastic polyester elastomer provided by the present invention, a benzotriazole structure and a tetramethylpiperidine group are introduced into the molecular structure of the polyester, and through the compounding of the two, not only the light aging resistance of the thermoplastic polyester elastomer can be improved, but also there is no exudation on the surface of the specimens during the processing and after long-term storage, meeting the requirements of the automotive interior for the color change of light-colored materials after light aging; after 500 h of light exposure, the color difference of the thermoplastic polyester elastomer is ≤ 1.59, and the gray scale rating is above 4; the exudation resistance is good.

[0105] The above specific embodiments have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thermoplastic polyester elastomer, characterized in that The thermoplastic polyester elastomer comprises an aromatic dibasic acid residue and an aliphatic polyol residue; Based on the total molar amount of the aliphatic polyol residue being 100 mol%, the aliphatic polyol residue comprises 66 to 95 mol% of small molecule diol residues, 2 to 24 mol% of polymer polyol residues and 1.5 to 10 mol% of a third polyol residue; The third polyol residue includes a residue derived from a benzotriazole compound and a residue derived from a tetramethylpiperidine compound.

2. The thermoplastic polyester elastomer according to claim 1, characterized in that Based on the total molar amount of the aliphatic polyol residue as 100 mol%, the molar percentage of the residue derived from the benzotriazole compound in the aliphatic polyol residue is 0.05 to 2.1 mol%, more preferably 0.4 to 1.5 mol%; Preferably, the number of hydroxyl groups in the molecular structure of the benzotriazole compound is ≥2, and more preferably, the number of hydroxyl groups in the molecular structure of the benzotriazole compound is 3.

3. The thermoplastic polyester elastomer according to claim 1 or 2, characterized in that: The benzotriazole compound has a structure shown in Formula I; In formula I, R1 is selected from any one of H, halogen, or C1-C6 straight-chain or branched alkyl; R2, R3, R4, and R5 are each independently selected from H, hydroxyl, C1-C6 straight-chain or branched alkyl, C1-C6 straight-chain or branched alkyl in which at least one H is substituted by hydroxyl, or Any one of; and the total number of hydroxyl groups in R2, R3, R4, and R5 is ≥ 1, and more preferably the total number of hydroxyl groups in R2, R3, R4, and R5 is 2; R 11 , R 12 , R 13 Each is independently selected from any one of H, hydroxyl, C1-C6 straight-chain or branched alkyl, or C1-C6 straight-chain or branched alkyl in which at least one H is substituted by hydroxyl; m, n are each independently selected from integers of 0-4; "*" represents a connection site; Preferably, the benzotriazole compound includes At least one of 3-(2H-benzotriazol-2-yl)-4-hydroxyphenylethanol or 2-(2,4-dihydroxyphenyl)-2H-benzotriazole.

4. The thermoplastic polyester elastomer according to any one of claims 1 to 3, characterized in that Based on the total molar amount of the aliphatic polyol residues as 100 mol%, the molar percentage of the residues derived from tetramethylpiperidine compounds in the aliphatic polyol residues is 0.5 to 9.5 mol%, more preferably 1.5 to 7.5 mol%. Preferably, the tetramethylpiperidine compound has a structure shown in Formula II; In formula II, R1 and R2 are each independently selected from any one of H, hydroxyl, C1-C6 straight chain or branched alkyl, or C1-C6 straight chain or branched alkyl in which at least one H is substituted by a hydroxyl group; and the total number of hydroxyl groups in R1 and R2 is ≥ 2, more preferably the total number of hydroxyl groups in R1 and R2 is 2; Preferably, R1 is selected from -OH; R2 is selected from -CH2CH2OH.

5. The thermoplastic polyester elastomer according to any one of claims 1 to 4, characterized in that The aromatic dibasic acid residue comprises at least one of a terephthalic acid residue, a phthalic acid residue or an isophthalic acid residue; Preferably, the small molecule diol residue comprises a C2-C6 aliphatic diol residue; Preferably, the small molecule diol residue includes at least one of an ethylene glycol residue, a 1,3-propylene glycol residue, a 1,4-butylene glycol residue, a 1,5-pentanediol residue or a 1,6-hexanediol residue.

6. The thermoplastic polyester elastomer according to any one of claims 1 to 5, characterized in that: The polymer polyol residues include polyether polyol residues; Preferably, the polyether polyol residue comprises a polytetramethylene glycol residue; Preferably, the number average molecular weight of the polymer polyol residue is 1000 to 3200; Preferably, the viscosity of a dilute solution of the thermoplastic polyester elastomer with a mass concentration of 0.005 g / mL is 1.0 to 2.0 dL / g.

7. A method for preparing a thermoplastic polyester elastomer according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: The aromatic dibasic acid, the small molecule diol, the polymer polyol and the third polyol are mixed and reacted to obtain the thermoplastic polyester elastomer.

8. The preparation method according to claim 7, characterized in that: The mixed raw materials also include a catalyst and / or an antioxidant; Preferably, the reaction comprises: S1: reacting an aromatic dibasic acid with a small molecular diol to obtain product A; S2: reacting the product A with a polymer polyol and a third polyol to obtain a product B; S3: subjecting the product B to a polycondensation reaction to obtain the thermoplastic polyester elastomer; Preferably, the reaction temperature in step S1 is 190-230° C., and the reaction time is 0.5-3 h; Preferably, the reaction temperature in step S2 is 190-230° C., and the reaction time is 0.5-3 h; Preferably, the temperature of the polycondensation reaction in step S3 is 235-255° C., the reaction pressure is ≤100 Pa, and the reaction time is 2-4 h.

9. A polyester composition, characterized in that The polyester composition comprises the thermoplastic polyester elastomer according to any one of claims 1 to 6; Preferably, the polyester composition further comprises at least one of a filler, an auxiliary agent or a pigment.

10. An automobile interior, characterized in that: The material for automobile interior decoration comprises the thermoplastic polyester elastomer according to any one of claims 1 to 6 or the polyester composition according to claim 9.

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