Copolyesters, processes for their preparation and use
By introducing specific structural units into the copolyester and carrying out esterification polycondensation reaction, the problem of decreased mechanical properties caused by the addition of TPEE flame retardant was solved, and a copolyester with high flame retardant performance and good mechanical properties was prepared, which is suitable for automotive parts and wire and cable fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-27
- Publication Date
- 2026-06-30
AI Technical Summary
While existing technologies improve the flame retardant properties of TPEE, they also result in a decline in mechanical properties, especially in applications such as automotive parts and wires and cables, where the addition of flame retardants leads to a loss of material properties.
By introducing structural units A, B, and C into the copolyester, the flame retardant properties are improved by utilizing halogen side chains, and the copolyester is prepared through esterification and polycondensation reactions, while maintaining the mechanical properties and damping effect of the material.
It achieves the goal of improving flame retardant properties while maintaining or enhancing the mechanical properties and damping effect of copolyester, making it suitable for industrial production.
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Figure CN122302240A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyesters, and more specifically, to a copolyester, its preparation method, and its applications. Background Technology
[0002] Polyether ester elastomer (TPEE) is a block copolyester containing hard polyester segments and soft polyether segments. The soft segments impart elasticity, while the hard segments provide processability, thus combining the excellent properties of both rubber and engineering plastics. Due to its outstanding mechanical strength, excellent resilience, and wide operating temperature range, TPEE has been widely used in automotive parts, electronics, wires and cables, and other fields.
[0003] Some automotive parts, such as intake pipes or wires and cables that come into contact with the engine, require TPEE to have high flame retardant properties. However, most TPEE elastomers use polyethers such as polytetrahydrofuran and polyethylene glycol as modified raw materials. The long aliphatic chain structure of polyethers makes TPEE products flammable, with a limiting oxygen index of <20. To improve the flame retardant properties of TPEE elastomers, most current technical solutions involve blending a large amount of flame retardant with TPEE. For example, CN112321993A describes a composite flame retardant prepared by mixing aluminum diethylphosphinate and melamine urate at a mass ratio of 2:1, with a flame retardant content of 20%-30%. However, due to the addition of a large amount of flame retardant, the mechanical properties of the TPEE material are significantly reduced. CN102391621A uses synergistic flame retardants such as phosphate esters, melamine, zinc borate, and modified nano-clay, with a flame retardant content of 20-40 wt%. Cellulose acetate is added to compensate for the loss of mechanical properties. Although this provides some compensation, the limiting oxygen index reaches over 30, resulting in a performance decrease of about 15%. CN106947223A requires the addition of 15-25 parts of alkyl hypophosphite as a flame retardant to achieve a limiting oxygen index of over 30, but the mechanical properties of the TPEE elastomer are not characterized.
[0004] Therefore, there is an urgent need to provide a copolyester that has both good flame retardant properties and good mechanical properties. Summary of the Invention
[0005] The purpose of this invention is to overcome the problem that adding flame retardants to TPEE improves its flame retardant properties while reducing its mechanical properties. This invention provides a copolyester, its preparation method, and its application. This copolyester improves its flame retardant properties while also exhibiting good mechanical properties and enhancing its damping effect.
[0006] To achieve the above objectives, the first aspect of the present invention provides a copolyester containing structural unit A of formula (I), structural unit B of formula (II), and structural unit C of formula (III); Formula (I); Formula (II); Formula (III); In this system, R1 and R2 are each independently C1-C4 alkylene groups, R3, R4, R5 and R6 are each independently hydrogen or C1-C4 alkyl groups, R7 is a C2-C10 alkylene group, and X is a halogen.
[0007] A second aspect of the present invention provides a method for preparing a copolyester, the method comprising the following steps: (1) Under esterification reaction conditions, a modified monomer having the structure shown in formula (I), a dicarboxylic acid monomer having the structure shown in formula (II), a diol monomer having the structure shown in formula (III) and a catalyst are mixed to carry out the first stage reaction to obtain a prepolymer; (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction; Formula (I); Formula (II); Formula (III); In this structure, R1 and R2 are each independently C1-C4 alkylene, R3, R4, R5 and R6 are each independently hydrogen or C1-C4 alkyl, R7 is C2-C10 alkylene, X is halogen, and the degree of polymerization of the structure shown in formula (I) is 3-30.
[0008] The third aspect of this invention provides the application of the copolyester described in the first aspect and / or the copolyester obtained by the preparation method described in the second aspect in automotive manufacturing materials.
[0009] Through the above technical solution, the copolyester provided by the present invention contains structural units A, B, and C. Structural units A, B, and C participate in the construction and rearrangement of polyester macromolecular segments, effectively altering the polymer's structure and properties. While breaking the chain segment regularity, the halogens in the side chains significantly improve the flame retardant properties of the copolyester, while also exhibiting good mechanical properties. Furthermore, the presence of side chains in the polyester enhances its damping effect. The process route for this copolyester is simple and easy for continuous industrial production.
[0010] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation
[0011] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0012] In a first aspect, the present invention provides a copolyester containing structural unit A of formula (I), structural unit B of formula (II), and structural unit C of formula (III); Formula (I); Formula (II); Formula (III); In this system, R1 and R2 are each independently C1-C4 alkylene groups, R3, R4, R5 and R6 are each independently hydrogen or C1-C4 alkyl groups, R7 is a C2-C10 alkylene group, and X is a halogen.
[0013] In this invention, R1 and R2 can each be independently a straight-chain C1-C4 alkylene or a branched C2-C4 alkylene. For example, R1 and R2 can each be independently methylene, ethylene, propylene, butylene, etc.; R3, R4, R5 and R6 can each be independently hydrogen, straight-chain C1-C4 alkyl, branched C3-C4 alkyl or C3-C4 cycloalkyl. For example, they can be hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl and cyclobutyl, etc.; R7 is a C2-C10 alkylene. For example, R7 can be ethylene, propyleneene, butylene, pentylene, hexylene, heptylene, octylene, nonylene or decylene; X is a halogen, for example, F, Cl, Br and I, etc.
[0014] The copolyester provided by this invention contains structural units A, B, and C. These structural units participate in the construction and rearrangement of polyester macromolecular segments, effectively altering the polymer's structure and properties. While breaking the chain segment regularity, the halogens in the side chains significantly improve the flame retardant properties of the copolyester, while also providing good mechanical properties. Furthermore, the presence of side chains enhances the damping effect of the copolyester. The process route for this copolyester is simple and easy for continuous industrial production.
[0015] According to the present invention, preferably, the degree of polymerization of the structural unit A is 3-30, specifically 3, 10, 20, 30, or any value between the two aforementioned values. The inventors have found that, under this preferred embodiment, by having the structural unit A with the aforementioned degree of polymerization participate in the construction and rearrangement of polyester macromolecular segments, it is possible to further improve the flame retardant properties of the copolyester while also exhibiting better mechanical properties and enhancing its damping effect.
[0016] According to the present invention, in order to further improve the flame retardant properties of the copolyester while simultaneously enhancing its damping effect and mechanical properties, preferably, R1 and R2 are each independently methylene or ethylene, R3, R4, R5 and R6 are each independently hydrogen or methyl, R7 is a C2-C4 alkylene, and X is Cl or Br. More preferably, R1 and R2 are methylene, R3, R4, R5 and R6 are hydrogen, and X is Cl.
[0017] According to the present invention, preferably, the halogen content in the copolyester is 7-28 wt%, specifically 7 wt%, 11 wt%, 15 wt%, 20 wt%, 25 wt%, 28 wt%, or any value between the aforementioned two values; the content of structural unit B is 15-50 wt%, specifically 15 wt%, 30 wt%, 40 wt%, 50 wt%, or any value between the aforementioned two values. The inventors have found that, under this preferred embodiment, controlling the halogen content in the copolyester within the corresponding range can further improve the flame retardant properties of the copolyester. More preferably, the halogen content in the copolyester is 11-23 wt%.
[0018] According to the present invention, in order to further improve the flame retardant properties of the copolyester while simultaneously enhancing its damping effect and mechanical properties, preferably, the weight ratio of structural unit A to structural unit B, expressed in terms of halogen content, in the copolyester is 1:0.6-6, specifically 1:0.6, 1:2, 1:4, 1:6, or any value between the aforementioned two. It should be noted that the weight ratio of structural unit A to structural unit B, expressed in terms of halogen content, refers to the ratio of the weight of halogen in structural unit A to the weight of structural unit B.
[0019] In this invention, the method for determining the structural units B and C of the copolyester and their content includes: using an infrared spectrometer and a nuclear magnetic resonance spectrometer to identify the presence of structural units B and C in the copolyester; simultaneously, structural units B and C have characteristic hydrogen chemical shifts in the nuclear magnetic resonance, and the molar ratio of different units is calculated based on the peak area to achieve content determination.
[0020] In this invention, the halogen content in the copolyester can be determined by elemental content detection method.
[0021] According to the present invention, preferably, the copolyester has a limiting oxygen index greater than 22 and a tensile strength of 10-35 MPa, specifically 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, or any value between the aforementioned two values; and an elongation at break of 400-1000%, specifically 400%, 600%, 800%, 1000%, or any value between the aforementioned two values. The copolyester having the above performance parameters exhibits good flame retardant properties and mechanical properties. More preferably, the copolyester has a limiting oxygen index greater than 30, a tensile strength of 17-35 MPa, and an elongation at break of 480-950%.
[0022] In this invention, the limiting oxygen index of the copolyester is tested according to the "FZ / T 50017-2011 Test Method for Flame Retardant Properties of Polyester Fibers - Oxygen Index Method". The test process includes: fixing the sample vertically in a transparent combustion tube containing an upward-flowing mixture of oxygen and nitrogen gas, igniting the top of the sample, observing the combustion characteristics of the sample, comparing the burning length of the sample with a given criterion, estimating the minimum oxygen concentration through a series of tests at different oxygen concentrations; each sample is tested three times, and the average value is taken.
[0023] In this invention, the tensile strength and elongation at break of the copolyester are tested in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.
[0024] During their research, the inventors of this invention unexpectedly discovered that by involving structural units A, B, and C in the construction and rearrangement of polyester macromolecular segments, in addition to improving the flame retardant properties of the copolyester, its damping effect can also be enhanced, thereby improving the vibration reduction and noise reduction effects of the copolyester, without compromising its original mechanical properties. Preferably, the damping factor of the copolyester is greater than 0.18. More preferably, the damping factor of the copolyester is greater than 0.28.
[0025] In this invention, the damping factor of the copolyester is tested in accordance with GB / T 18258-2000 Test Method for Damping Performance of Damping Materials.
[0026] According to the present invention, preferably, the copolyester further contains a metallic element. The inventors have found that, under this preferred embodiment, the flame retardant properties of the copolyester can be further improved, and it also exhibits good polyester properties.
[0027] In this invention, the metal element in the copolyester can improve the flame retardant properties of the copolyester, thereby improving its polyester properties. To further improve the flame retardant and polyester properties of the copolyester, preferably, the metal element is titanium and / or tin.
[0028] According to the present invention, in order to further improve the flame retardant properties and polyester properties of the copolyester, preferably, the content of metal elements in the copolyester is 120-350 ppm, specifically 120 ppm, 200 ppm, 300 ppm, 350 ppm, or any value between the two aforementioned values.
[0029] The content of the above-mentioned metal elements can be determined by elemental content detection method.
[0030] Secondly, the present invention provides a method for preparing a copolyester, the method comprising the following steps: (1) Under esterification reaction conditions, a modified monomer having the structure shown in formula (I), a dicarboxylic acid monomer having the structure shown in formula (II), a diol monomer having the structure shown in formula (III) and a catalyst are mixed to carry out the first stage reaction to obtain a prepolymer; (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction; Formula (I); Formula (II); Formula (III); R1 and R2 can each be independently a straight-chain C1-C4 alkylene or a branched C2-C4 alkylene. For example, R1 and R2 can each be independently methylene, ethylene, propylene, butylene, etc.; R3, R4, R5, and R6 can each be independently hydrogen or C1-C4 alkyl. The C1-C4 alkyl can be a straight-chain C1-C4 alkyl, a branched C3-C4 alkyl, or a C3-C4 cycloalkyl, for example, hydrogen, methyl, ethyl, or n-alkyl. Propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl, and cyclobutyl, etc.; R7 is a C2-C10 alkylene, for example, R7 is ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, or decylene; X is a halogen, such as F, Cl, Br, and I, etc.; the degree of polymerization of the structure shown in formula (I) is 3-30, specifically 3, 10, 20, 30, or any value between the two aforementioned values.
[0031] According to the present invention, the preparation method of the copolyester is simple and suitable for industrial production.
[0032] According to the present invention, in order to further improve the flame retardant properties of the copolyester while simultaneously enhancing its damping effect and mechanical properties, preferably, R1 and R2 are each independently methylene or ethylene, R3, R4, R5 and R6 are each independently hydrogen or methyl, R7 is a C2-C4 alkylene, and X is Cl or Br. More preferably, R1 and R2 are methylene, R3, R4, R5 and R6 are each independently hydrogen, and X is Cl.
[0033] In this invention, when R1 and R2 are each independently methylene and X is Cl, the modified monomer is polyepoxychloropropane, CAS number 24969-06-0.
[0034] In this invention, when R3, R4, R5 and R6 are each independently hydrogen or methyl, the dicarboxylic acid monomer can, by example, be terephthalic acid, 2-methyl-1,4-phthalic acid, or 2,5-dimethyl-1,4-phthalic acid, and more preferably terephthalic acid; when R7 is a C2-C4 alkylene oxide, the diol monomer can, by example, be ethylene glycol, propylene glycol, or butanediol, and more preferably butanediol.
[0035] According to the present invention, the molecular weight of the modified monomer can be 500-15000. To further improve the flame retardant properties of the copolyester while simultaneously enhancing its damping effect and mechanical properties, preferably, the molecular weight of the modified monomer is 3000-8000, specifically 3000, 5000, 8000, or any value between the aforementioned two. It should be noted that the molecular weight of the modified monomer refers to its number-average molecular weight.
[0036] In this invention, when the modified monomer is polyepoxychloropropane with a molecular weight of 500-15000, polyepoxychloropropane can be obtained commercially or prepared by oneself.
[0037] In this invention, polyepoxychloropropane with a molecular weight of 500-15000 can be prepared according to the method in CN101701063A. For example, the preparation process of polyepoxychloropropane with a molecular weight of 3200 is as follows: 35 ml of dichloromethane and 0.001 mol of ethoxytriphenylphosphine tetrafluoride are added sequentially to a three-necked flask equipped with a stir bar. After stirring at room temperature for 25 minutes, 0.5 ml of boron trifluoride is added, and the system temperature is lowered to 0°C. Then, 18 ml of epichlorohydrin is added dropwise, maintaining the temperature at 0°C by controlling the dropping rate to 1-2 drops / second and using an ice-water bath. After reacting for 8 hours, 10 ml of a methanol solution containing 10% NaOH is added, and the reaction is terminated after stirring at room temperature for 50 minutes. The crude product is then separated. The crude product is then repeatedly washed with distilled water until neutral; then, small molecules such as solvents are removed by rotary evaporation under reduced pressure at 70°C; the number-average molecular weight of polyepoxychloropropane can be determined by gel permeation chromatography (GPC) using polystyrene as a standard and tetrahydrofuran (THF) as the mobile phase.
[0038] According to the present invention, in order to further improve the reaction efficiency and product yield, and improve the performance of the copolyester, preferably, the catalyst contains a titanium-based catalyst and / or a tin-based catalyst.
[0039] According to the present invention, there is no particular limitation on the type of titanium-based catalyst or tin catalyst. In order to further improve the reaction efficiency and product yield, and improve the performance of copolyester, preferably, the titanium-based catalyst is selected from at least one of tetrabutyl titanate, titanium glycolate and isopropyl titanate, and more preferably tetrabutyl titanate and / or titanium glycolate; the tin-based catalyst is monobutyltin and / or tetrabutyltin.
[0040] According to the present invention, in order to improve the flame retardant properties and damping effect of the copolyester while further improving the mechanical properties of the copolyester, preferably, the molar ratio of the diacid monomer to the diol monomer is 0.2-0.4:1, specifically 0.2:1, 0.3:1, 0.4:1, or any value between the two aforementioned values.
[0041] According to the present invention, in order to further improve the mechanical properties of the copolyester while enhancing its flame retardant properties and damping effect, preferably, the amount of the modified monomer relative to 100g of the diacid monomer is 30-350g, specifically 30g, 100g, 150g, 200g, 250g, 300g, 350g, or any value between the aforementioned two values; the amount of the catalyst is 0.09-0.5g, specifically 0.09g, 0.2g, 0.3g, 0.4g, 0.5g, or any value between the aforementioned two values. More preferably, relative to 100g of the diacid monomer, the amount of the modified monomer is 58-200g, and the amount of the catalyst is 0.09-0.32g.
[0042] In this invention, the aforementioned dicarboxylic acid monomer, diol monomer, modified monomer, and catalyst can all be obtained commercially or prepared by means of methods disclosed in the prior art.
[0043] According to the present invention, preferably, in step (1), the conditions for the esterification reaction include at least: a temperature of 190-230°C, specifically 190°C, 200°C, 210°C, 220°C, 230°C, or any value between the two aforementioned values; a gauge pressure of 0-0.4 MPa, specifically 0 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, or any value between the two aforementioned values; and the conditions for the termination of the esterification reaction process include at least: the amount of water produced is greater than 95% of the theoretical amount of water produced.
[0044] According to the present invention, preferably, in step (2), the conditions for the polycondensation reaction include at least: a temperature of 240-260°C, specifically 240°C, 250°C, 260°C, or any value between the two aforementioned values; an absolute pressure of 0-100 Pa, specifically 0 Pa, 50 Pa, 100 Pa, or any value between the two aforementioned values; and the conditions for the end of the polycondensation reaction process include at least: the stirring power reaching a preset value. The inventors have found that, under this preferred embodiment, the product of the esterification reaction has a better polycondensation effect, improving the stability of the structure and properties of the copolyester.
[0045] In this invention, both the first-stage reaction and the second-stage reaction are carried out under stirring conditions, with the stirring speed controlled at 25-50 rpm.
[0046] It should be noted that the preset value of the stirring power in this invention is the rated power value of the reactor used. Different reactors have different rated power values.
[0047] According to a particularly preferred embodiment of the present invention, a method for preparing a copolyester is provided, the method comprising the following steps: (1) Under esterification reaction conditions, a modified monomer having the structure shown in formula (I), a diacid monomer having the structure shown in formula (II), a diol monomer having the structure shown in formula (III) and a catalyst are mixed and the first stage reaction is carried out at a temperature of 190-230℃ and a gauge pressure of 0-0.4MPa to obtain a prepolymer. (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction at a temperature of 240-260℃ and an absolute pressure of 0-100Pa; Formula (I); Formula (II); Formula (III); Wherein, R1 and R2 are each independently methylene or ethylene, R3, R4, R5 and R6 are each independently hydrogen or methyl, R7 is C2-C4 alkylene, and X is Cl or Br; the molecular weight of the modified monomer having the structure shown in formula (I) is 3000-8000. The catalyst contains a titanium-based catalyst and / or a tin-based catalyst; the titanium-based catalyst is tetrabutyl titanate and / or titanium glycolate; the tin-based catalyst is monobutyltin and / or tetrabutyltin; the molar ratio of the diacid monomer to the diol monomer is 0.2-0.4:1; relative to 100g of the diacid monomer, the amount of the modified monomer is 58-200g, and the amount of the catalyst is 0.09-0.32g.
[0048] In the preferred embodiments described above, the prepared copolyester not only improves the flame retardant properties but also enhances the damping effect and mechanical properties of the copolyester. Furthermore, the preparation method is simple, easy to synthesize, and has significant market potential.
[0049] Thirdly, the present invention provides the application of the copolyester described in the first aspect and / or the copolyester obtained by the preparation method described in the second aspect in automotive manufacturing materials.
[0050] The present invention will be described in detail below with reference to embodiments, but this does not limit the scope of the invention.
[0051] In the following examples, polyepoxychloropropanes with molecular weights of 1000, 3000, 4000, 5000, 8000, 10000, and 15000 were all purchased in-house. Unless otherwise specified, all other raw materials or reagents were conventional commercial products.
[0052] In the following examples, the halogen content and metal element content in the copolyester were determined by elemental content detection method.
[0053] The contents of structural units B and C in the copolyester were obtained through infrared and nuclear magnetic resonance (NMR) analysis; the specific composition was obtained through gas / liquid chromatography (GC). Specifically, the GC method involved methanol hydrolysis of the copolyester, with tetraethylene glycol dimethyl ether as an internal standard, and detection using an HP5890 GC. FTIR spectroscopy primarily utilized a Fourier transform infrared spectrometer to rapidly compare and analyze the chemical composition and molecular structure of the particulate polyester by measuring its infrared spectrum.
[0054] The limiting oxygen index of copolyester was tested according to the "FZ / T 50017-2011 Test Method for Flame Retardant Properties of Polyester Fibers - Oxygen Index Method". The test process included: fixing the sample vertically in a transparent combustion tube with an upward-flowing mixture of oxygen and nitrogen gas, igniting the top of the sample, observing the combustion characteristics of the sample, comparing the burning length of the sample with the given criteria, and estimating the minimum oxygen concentration through a series of tests at different oxygen concentrations; each sample was tested three times and the average value was taken.
[0055] The tensile strength and elongation at break of the copolyester were tested in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.
[0056] The damping factor of the copolyester was tested according to GB / T 18258-2000 Test Method for Damping Performance of Damping Materials.
[0057] Example 1 274.65g of terephthalic acid, 446g of 1,4-butanediol, 160g of polyepoxychloropropane (molecular weight 4000) and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterification was carried out at a temperature of 190-230℃ and a gauge pressure of 0MPa. Esterification was stopped when the esterification rate was ≥95%. Polycondensation was then carried out at a temperature of 240-260℃ and a pressure of 0-100Pa. After the stirring current reached the rated value, the product was discharged to obtain a copolyester.
[0058] Example 2 235.42g of terephthalic acid, 446g of 1,4-butanediol, 208g of polyepoxychloropropane (molecular weight 3000) and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterification was carried out at a temperature of 190-230℃ and a gauge pressure of -0.2MPa. Esterification was stopped when the esterification rate was ≥95%. Polycondensation was then carried out at a temperature of 240-260℃ and a pressure of 0-100Pa. After the stirring current reached the rated value, the product was discharged to obtain a copolyester.
[0059] Example 3 196.18g of terephthalic acid, 425.45g of 1,4-butanediol, 260g of polyepoxychloropropane (molecular weight 5000) and 0.3g of monobutyltin catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0060] Example 4 The copolyester was prepared according to the method of Example 1, except that 0.5 g of tetrabutyl titanate catalyst was replaced with 0.25 g of titanium glycol.
[0061] Example 5 156.95g of terephthalic acid, 340.37g of 1,4-butanediol, 312g of polyepoxychloropropane (molecular weight 8000) and 0.5g of tetrabutyltin catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0062] Example 6 The copolyester was prepared according to the method of Example 1, except that the amount of polyepoxychloropropane was replaced with 90g.
[0063] Example 7 118g of terephthalic acid, 255.27g of 1,4-butanediol, 364g of polyepoxychloropropane (molecular weight 10000) and 0.5g of tetrabutyltin catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0064] Example 8 The copolyester was prepared according to the method of Example 1, except that the molecular weight of polyepoxychloropropane was replaced with 15,000.
[0065] Example 9 The copolyester was prepared according to the method of Example 1, except that the molecular weight of polyepoxychloropropane was replaced with 1000.
[0066] Comparative Example 1 274.65g of terephthalic acid, 446g of 1,4-butanediol, 156g of polytetrahydrofuran (average molecular weight 1000, purchased from Maclean's reagent, model P816810) and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterification was carried out at a temperature of 190-230℃ and a pressure of 0-0.4MPa. Esterification was stopped when the esterification rate was ≥95%. Polycondensation was then carried out at a temperature of 240-260℃ and a pressure of 0-100Pa. After the stirring current reached the rated value, the product was discharged to obtain a copolyester.
[0067] Comparative Example 2 118g of terephthalic acid, 255.27g of 1,4-butanediol, 364g of polytetrahydrofuran (average molecular weight 2900, purchased from Maclean's reagent, model P903556) and 0.5g of tetrabutyltin catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0068] Comparative Example 3 274.65g of terephthalic acid, 446g of 1,4-butanediol, 156g of polytetrahydrofuran (average molecular weight 2900, purchased from Maclean's reagent, model P903556), 50g of 2-carboxyethylphenylphosphonic acid (CEPPA), and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0069] Comparative Example 4 274.65g of terephthalic acid, 446g of 1,4-butanediol, 156g of polytetrahydrofuran (average molecular weight 2900, purchased from Maclean's reagent, model P903556) and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterification was carried out at a temperature of 190-230℃ and a pressure of 0-0.4MPa. Esterification was stopped when the esterification rate was ≥95%. Polycondensation was then carried out at a temperature of 240-260℃ and a pressure of 0-100Pa. After the stirring current reached the rated value, the product was discharged to obtain a copolyester.
[0070] Comparative Example 5 274.65g of terephthalic acid, 446g of 1,4-butanediol, and 0.5g of tetrabutyl titanate catalyst were added to a reactor and esterified at 190-230℃ and 0-0.4MPa. Esterification was terminated when the esterification rate was ≥95%. Polycondensation was then carried out at 240-260℃ and 0-100Pa. The product was discharged after the stirring current reached the rated value to obtain a copolyester.
[0071] Table 1
[0072] Table 2
[0073] As shown in Table 1, compared with Comparative Examples 1-5, the copolyesters prepared by the method provided by the present invention in Examples 1-9 have better flame retardant properties, as well as better damping effect and mechanical properties, and have significant market prospects.
[0074] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A copolyester, characterized in that, The copolyester contains structural unit A as shown in formula (I), structural unit B as shown in formula (II), and structural unit C as shown in formula (III); Formula (I); Formula (II); Formula (III); In this system, R1 and R2 are each independently C1-C4 alkylene groups, R3, R4, R5 and R6 are each independently hydrogen or C1-C4 alkyl groups, R7 is a C2-C10 alkylene group, and X is a halogen.
2. The copolyester according to claim 1, characterized in that, The degree of polymerization of structural unit A is 3-30.
3. The copolyester according to claim 1, characterized in that, R1 and R2 are each independently methylene or ethylene, R3, R4, R5 and R6 are each independently hydrogen or methyl, R7 is C2-C4 alkylene, and X is Cl or Br. Preferably, the copolyester contains 7-28 wt% halogen and 15-50 wt% structural unit B. Preferably, in the copolyester, the weight ratio of structural unit A to structural unit B, calculated in terms of halogens, is 1:0.6-6.
4. The copolyester according to any one of claims 1 to 3, characterized in that, The copolyester has a limiting oxygen index greater than 22, a tensile strength of 10-35 MPa, and an elongation at break of 400-1000%. Preferably, the damping factor of the copolyester is greater than 0.
18.
5. The copolyester according to any one of claims 1 to 3, characterized in that, The copolyester also contains metallic elements; Preferably, the metallic element is titanium and / or tin; Preferably, the content of metal elements in the copolyester is 120-350 ppm.
6. A method for preparing a copolyester, characterized in that, The method includes the following steps: (1) Under esterification reaction conditions, a modified monomer having the structure shown in formula (I), a dicarboxylic acid monomer having the structure shown in formula (II), a diol monomer having the structure shown in formula (III) and a catalyst are mixed to carry out the first stage reaction to obtain a prepolymer; (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction; Formula (I); Formula (II); Formula (III); In this structure, R1 and R2 are each independently C1-C4 alkylene, R3, R4, R5 and R6 are each independently hydrogen or C1-C4 alkyl, R7 is C2-C10 alkylene, X is halogen, and the degree of polymerization of the structure shown in formula (I) is 3-30.
7. The preparation method according to claim 6, characterized in that, R1 and R2 are each independently methylene or ethylene, R3, R4, R5 and R6 are each independently hydrogen or methyl, R7 is C2-C4 alkylene, and X is Cl or Br. Preferably, the molecular weight of the modified monomer is 3000-8000; Preferably, the catalyst contains a titanium-based catalyst and / or a tin-based catalyst; Preferably, the titanium-based catalyst is selected from at least one of tetrabutyl titanate, titanium glycolate, and isopropyl titanate, and more preferably tetrabutyl titanate and / or titanium glycolate; the tin-based catalyst is monobutyltin and / or tetrabutyltin.
8. The preparation method according to claim 6 or 7, characterized in that, The molar ratio of the diacid monomer to the diol monomer is 0.2-0.4:1; Preferably, relative to 100g of the dicarboxylic acid monomer, the amount of the modified monomer is 30-350g, and the amount of the catalyst is 0.09-0.5g.
9. The preparation method according to claim 6 or 7, characterized in that, In step (1), the conditions for the esterification reaction include at least: a temperature of 190-230℃; and a gauge pressure of 0-0.4MPa. Preferably, in step (2), the conditions for the polycondensation reaction include at least: a temperature of 240-260°C and an absolute pressure of 0-100Pa.
10. The use of the copolyester according to any one of claims 1 to 5 and / or the copolyester obtained by the preparation method according to any one of claims 6 to 9 in automotive manufacturing materials.