Modified polyesters, processes for their preparation and use

Abstract

The present application relates to modified copolyester material, disclose a kind of modified polyester and its preparation method and application.Modified polyester is less than or equal to 130 ℃, modified polyester and polyvinyl chloride are melt-mixed to form composite particles with weight ratio 1:0.5-2, then with toughening agent is co-extrusion mixed to be made into the composite board material with thickness 1-2cm with weight ratio 1:0.1-0.15, the impact resistance of composite board material is 390kg / mm above.Modified polyester preparation method includes: under esterification reaction condition, after modified monomer, dibasic acid monomer, dibasic alcohol monomer and catalyst are mixed, first stage reaction is carried out;Under polycondensation reaction condition, second stage reaction is carried out, modified monomer contains polyhydric alcohol with formula (I) shown structure and monomer with formula (II) shown structure, and the molar ratio of monomer with formula (II) shown structure and dibasic acid monomer is 0.4-1.5:1.Modified polyester melting point is low, and the compatibility with polyvinyl chloride is good, and the composite material formed by melt-mixing of the two has excellent strength, toughness and cold resistance.

Description

Technical Field

[0001] This invention relates to modified copolyester materials, specifically to a modified polyester, its preparation method, and its applications. Background Technology

[0002] The sole materials for shoes are mainly polyvinyl chloride (PVC), polyethylene, polyethylene copolymers, polycaprolactone, and 1,4-cyclohexanediethanol (CHDM) modified polyester PETG. These materials are mixed with impact modifiers and processed into thick shoe plates. Impact modifiers mainly include epoxy-containing ethylene copolymers, anhydride-grafted ethylene copolymers (such as maleic anhydride copolymers), and polybutylene adipate is more commonly used. Among these base materials, PVC, polyethylene, and polyethylene copolymers are relatively inexpensive, but their performance is generally average; while polycaprolactone and PETG are expensive.

[0003] Polyethylene terephthalate (PET) and polybutylene terephthalate (PET) possess excellent mechanical and heat resistance properties, but poor impact resistance, especially at low temperatures below 0°C. Because these saturated polyesters have high melting points, they require high temperatures (>280°C) to be blended with impact modifiers. At these temperatures, the impact modifiers degrade significantly due to their poor temperature resistance. Therefore, conventional polyesters cannot be directly blended with impact modifiers; low-melting-point polyesters must be used. Currently, the method for preparing low-melting-point polyesters is to add some special copolymer modifying monomers. These monomers mainly include isophthalic acid, 2-methyl-1,3-propanediol, 2,2-methyl-1,3-propanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanediethanol (CHDM). For example, the isophthalic acid modified copolyester substrate used in CN1491987A uses isophthalic acid as the modifying monomer; CN108467479A uses furan dicarboxylic acid as the polyester modifying monomer; EP2411471A1 and CN104411766A both use 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanediethanol as polyester modifying monomers.

[0004] Although low-melting-point polyesters can be synthesized using the aforementioned modified monomers, these low-melting-point polyesters have poor compatibility with polyvinyl chloride (PVC), resulting in sheets with poor toughness and unsatisfactory impact resistance when blended. Furthermore, modified monomers such as 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanediethanol are relatively expensive. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor compatibility between low-melting-point polyester and polyvinyl chloride in the prior art, resulting in poor strength and toughness of the sheets produced by mixing. This invention provides a modified polyester, its preparation method, and its application.

[0006] The inventors of this invention discovered in their research that by using specific modified monomers as comonomers of polyester, a low-melting-point modified polyester can be synthesized. This modified polyester not only has a low melting point, allowing it to be effectively mixed with toughening agents to avoid degradation of the toughening agents, but also has good compatibility with polyvinyl chloride. The composite particles obtained by melt mixing the two can be further co-extruded and mixed with toughening agents to form a composite material with excellent strength, toughness, and cold resistance, making it suitable for producing shoe sole materials.

[0007] To achieve the above objectives, the first aspect of the present invention provides a modified polyester having a melting point less than or equal to 130°C. The modified polyester is melt-blended with polyvinyl chloride at a weight ratio of 1:0.5-2 to form composite particles, and then co-extruded with a toughening agent at a weight ratio of 1:0.1-0.15 to produce a composite sheet with a thickness of 1-2 cm. The impact resistance of the composite sheet is above 390 kg / mm.

[0008] A second aspect of the present invention provides a method for preparing a modified polyester, comprising the following steps:

[0009] (1) Under esterification reaction conditions, the modified monomer, diacid monomer, diol monomer and catalyst are mixed and the first stage reaction is carried out to obtain the prepolymer.

[0010] (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction;

[0011] The modified monomer contains a polyol having the structure shown in formula (I) and a monomer having the structure shown in formula (II).

[0012] Among them, R I and R II Each of the monomers is independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, and n is a positive integer from 4 to 11; R1, R2, R3 and R4 are each independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, more preferably hydrogen; the molar amount of the monomer having the structure shown in formula (II) accounts for 30-60% of the total molar amount of the monomer and the dicarboxylic acid monomer.

[0013] A third aspect of the present invention provides the application of the modified polyester described above and / or the modified polyester obtained by the above method in shoe sole materials.

[0014] A fourth aspect of the present invention provides a method for preparing a composite material, the method comprising the following steps:

[0015] S1. The modified polyester described above and / or the modified polyester obtained by the above method are mixed with polyvinyl chloride and additives, and then melt-blended to obtain composite particles.

[0016] S2. The composite particles are mixed with the toughening agent and then co-extruded and compounded.

[0017] The modified polyester provided by this invention not only has a low melting point, which allows it to be effectively mixed with toughening agents to avoid degradation of the toughening agents, but also has good compatibility with polyvinyl chloride. The composite particles obtained by melt mixing of the two can be further co-extruded and mixed with toughening agents to form composite materials with excellent strength, toughness and cold resistance, making them suitable for producing shoe sole materials.

[0018] The preparation method provided by this invention involves directly mixing multiple monomers and then carrying out esterification and polycondensation reactions to obtain modified polyesters. The method is simple to operate, has strong process controllability, and is suitable for industrial production. Detailed Implementation

[0019] 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.

[0020] The first aspect of the present invention provides a modified polyester having a melting point of 130°C or less. The modified polyester is melt-blended with polyvinyl chloride at a weight ratio of 1:0.5-2 to form composite particles, and then co-extruded with a toughening agent at a weight ratio of 1:0.1-0.15 to form a composite sheet with a thickness of 1-2 cm. The impact resistance of the composite sheet is above 390 kg / mm.

[0021] In this invention, the melting point is tested and characterized according to Method A (microscopic method) of 5.3.1 in GB / T 14190-2008 "Test Methods for Fiber Grade Polyester Chips (PET)".

[0022] In this invention, when preparing composite sheets using the modified polyester provided by this invention for performance testing, a twin-screw extruder is used. The specific method is as follows: the modified polyester provided by this invention is mixed with polyvinyl chloride (PVC) and optional additives in a twin-screw extruder (the weight ratio of modified polyester to PVC is 1:0.5-2), and the mixture is heated to 90-110°C and held for 25-35 minutes to obtain a mixture. Then, the mixture is plasticized and melt-extruded in a twin-screw extruder. The main extruder speed is 150-250 r / min, the pressure is 10-15 MPa, and the operating temperature is: from the feed port to the die, zone 1 temperature 100-120°C, zone 2 temperature 130-140°C, zone 3 temperature 140-150°C, and zone 4 temperature 150-160°C. After extrusion, stretching, and cooling... The composite particles are obtained by pelletizing and drying; the composite particles and toughening agent are co-extruded and compounded in a screw extruder at a weight ratio of 1:0.1-0.15 to produce a composite board with a thickness of 1-2 cm; the additives are zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate and dioctyl phthalate, and the toughening agent is selected from at least one of polybutylene succinate, polyethylene succinate, polycaprolactone and polybutylene adipate; the weight ratio of modified polyester, polyvinyl chloride, zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate, dioctyl phthalate and toughening agent is 1:0.8-1.2:0.01-0.05:0.02-0.08:0.02-0.08:0.01-0.05:0.02-0.08:0.2-0.3.

[0023] In this invention, the impact resistance test of the composite sheet is conducted according to the method in ASTM-D3763, "Standard Test Method for High-Speed ​​Puncture Performance of Plastics Using Load and Displacement Sensors," with 10 samples per batch. Preferably, the impact resistance of the composite sheet is above 400 kg / mm², more preferably above 410 kg / mm². The modified polyester provided by this invention, while having a low melting point, can form good compatibility with polyvinyl chloride (PVC). It can not only be effectively mixed with toughening agents to avoid degradation of the toughening agents, but also the material formed by mixing PVC and toughening agents has excellent strength, toughness, and cold resistance, strong impact resistance, and good flexural resistance, making it effective for use in the production of shoe sole materials.

[0024] According to the present invention, preferably, the melting point of the modified polyester is less than or equal to 120°C, more preferably, the melting point of the modified polyester is 100°C-120°C. Based on the low melting point of the modified polyester in this application, it can be compounded with toughening agents at lower temperatures, reducing or avoiding the degradation of toughening agents at high temperatures, which is beneficial to improving the impact resistance of the modified polyester.

[0025] According to the present invention, preferably, the modified polyester has a glass transition temperature of 60-70℃, an intrinsic viscosity of 0.7-0.85 dL / g, and a terminal carboxyl group content of 20-35 mol / t. This modified polyester has a low melting point, good compatibility with polyvinyl chloride, and a certain degree of increase in glass transition temperature, resulting in good processing performance.

[0026] In this invention, the glass transition temperature of the modified polyester is calculated using differential scanning calorimetry (DSC), the intrinsic viscosity is tested according to method 5.1 of GB / T14190-2017 Test Method for Fiber Grade Polyester Chips, and the terminal carboxyl groups are tested according to method 5.4 of GB / T14190-2017 Test Method for Fiber Grade Polyester Chips. The process of calculating the glass transition temperature using DSC includes: under nitrogen protection, using DSC thermal analysis, the temperature is increased from 25℃ to 290℃ at a heating rate of 10℃ / min, held for 5 min, then decreased to 25℃ at a rate of 400℃ / min, then increased again from 25℃ to 290℃ at a heating rate of 10℃ / min, held for 5 min, and finally decreased to 100℃ at a rate of 10℃ / min. The glass transition temperature Tg is then calculated based on the second heating curve.

[0027] According to the present invention, preferably, the modified polyester contains structural unit A represented by formula (I),

[0028] Among them, R I and R II Each component is independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, and n is a positive integer from 4 to 11. The inventors have discovered that, in this preferred embodiment, the modified polyester contains a large number of side-position -OH groups, which form a certain polar interaction with the polar side-position -Cl groups in polyvinyl chloride, resulting in good compatibility between the modified polyester and polyvinyl chloride (PVC).

[0029] According to the present invention, the above-mentioned structural unit A can be obtained by infrared and nuclear magnetic resonance detection analysis. Preferably, the content of structural unit A represented by formula (I) in the modified polyester is less than or equal to 1% by weight, more preferably 0.1-1% by weight. The inventors have found that, under this preferred embodiment, the compatibility between the modified polyester and polyvinyl chloride is better.

[0030] According to the present invention, preferably, the modified polyester further comprises structural unit B represented by formula (II) and structural unit C represented by formula (III).

[0031]

[0032] In this embodiment, R1, R2, R3, R4, R5, R6, R7, and R8 are each independently hydrogen or C1-C4 alkyl groups, such as hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; preferably hydrogen or methyl, more preferably hydrogen. The inventors have discovered that, in this preferred embodiment, structural unit A and structural unit B can cooperate to lower the melting point of the modified polyester and improve the compatibility between the modified polyester and polyvinyl chloride, resulting in shoe sole materials made from this modified polyester exhibiting better strength and toughness, and excellent flexural and bending resistance test results.

[0033] According to the present invention, preferably, the molar amount of structural unit B accounts for 30-60% of the total molar amount of structural unit B and structural unit C. The molar amounts of structural unit B and structural unit C can be determined by gas chromatography, respectively. The inventors have found that, under this preferred embodiment, it is advantageous to further reduce the melting point of the modified polyester and reduce the raw material cost for polyester modification.

[0034] According to the present invention, preferably, the modified polyester further contains antimony or titanium, more preferably, the content of antimony or titanium in the modified polyester is less than or equal to 0.05% by weight, more preferably less than or equal to 0.03% by weight.

[0035] A second aspect of the present invention provides a method for preparing a modified polyester, comprising the following steps:

[0036] (1) Under esterification reaction conditions, the modified monomer, diacid monomer, diol monomer and catalyst are mixed and the first stage reaction is carried out to obtain the prepolymer.

[0037] (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction;

[0038] The modified monomer contains a polyol having the structure shown in formula (I) and a monomer having the structure shown in formula (II).

[0039]

[0040] Among them, R I and R II Each of them is independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, and n is a positive integer from 4 to 11; R1, R2, R3 and R4 are each independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, more preferably hydrogen;

[0041] The molar amount of the monomer having the structure shown in formula (II) accounts for 30-60% of the total molar amount of the monomer and the dicarboxylic acid monomer.

[0042] The inventors discovered that, under the action of two modifying monomers, a polyol having the structure shown in formula (I) and a monomer having the structure shown in formula (II), mutually cooperative structural units A and B can be formed in the modified polyester, effectively reducing the melting point of the modified polyester and improving the compatibility of the modified polyester with polyvinyl chloride (PVC).

[0043] As a specific embodiment of the present invention, the structural formula of the polyol is shown in formula (IV). m is a positive integer from 3 to 10. The polyol shown in formula (IV) is a linear condensation compound of resorcinol and formaldehyde, which can be prepared by condensation reaction of resorcinol and formaldehyde as substrates. The inventors have found that, in this preferred embodiment, the polyol, as a modifying monomer, can better modify polyester and produce a modified polyester with good compatibility with PVC.

[0044] According to the present invention, preferably, the monomer having the structure shown in formula (II) is isophthalic acid, which is inexpensive and has a good modification effect on polyester copolymers.

[0045] In this invention, the diacid monomer can be any diacid that can be used to prepare polyester. Preferably, the diacid monomer is an acid or ester having the structure shown in formula (III). R5, R6, R7, and R8 are each independently hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, and more preferably hydrogen. Exemplarily, the dicarboxylic acid monomer can be terephthalic acid, dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, etc. The inventors have discovered that, in this preferred embodiment, the modified polyester contains structural unit B of formula (II) and structural unit C of formula (III), resulting in better compatibility between the polyester and PVC, and consequently, better impact resistance of the composite board.

[0046] In this invention, the diol monomer can be any diol that can be used to prepare polyester, preferably an aliphatic diol, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, etc., and more preferably ethylene glycol.

[0047] According to the present invention, preferably, the catalyst is an antimony-containing catalyst or a titanium-containing catalyst, more preferably selected from antimony glycolate, antimony acetate, antimony trioxide, titanium glycolate, nano titanium dioxide or tetrabutyl titanate; the amount of catalyst can be the same as that of conventional polyester. For example, based on 100 parts by weight of the dicarboxylic acid monomer, the amount of catalyst is 0.05-0.2 parts by weight.

[0048] In this invention, the polyols, monomers having the structure shown in formula (II), dicarboxylic acid monomers, diol monomers and catalysts are all commercially available or can be prepared by methods disclosed in the prior art.

[0049] According to the present invention, preferably, based on the total amount of the modified monomer, diacid monomer, diol monomer and catalyst, the amount of the polyol is less than or equal to 1% by weight, more preferably 0.1-1% by weight. In this preferred embodiment, the molar amount of the monomer having the structure shown in formula (II) accounts for 30-60% of the total molar amount of the monomer and diacid monomer, and the weight of the polyol accounts for less than 1% of the total weight of all substrates, which is beneficial to lowering the melting point of the modified polyester and further improving its compatibility with PVC.

[0050] In this invention, the termination condition for the first-stage reaction can be determined by the experimenter based on the actual situation; preferably, it can be determined based on the product's water output reaching the theoretical value. After the first-stage reaction, the pressure needs to be released to atmospheric pressure, and the temperature is gradually increased to enter a low-vacuum stage for the second-stage reaction. The termination condition for the second-stage reaction can also be determined by the experimenter based on the actual situation; preferably, it can be determined based on the stirring power reaching the rated value.

[0051] According to the present invention, preferably, in step (1), the esterification reaction conditions include at least: oxygen isolation, a temperature of 200-260°C, and a pressure of 2.2-2.8 MPa. The inventors have found that, under this preferred embodiment, polyols, monomers having the structure shown in formula (II), diol monomers, and diacid monomers exhibit better esterification effects, thereby enabling the subsequently obtained modified polyester to have higher processing performance. Oxygen isolation is typically achieved by introducing an inert gas such as nitrogen or helium into the reaction system. The first-stage reaction is carried out under stirring conditions, and the stirring rate can be determined by the experimenter based on the actual situation.

[0052] According to the present invention, preferably, in step (2), the polycondensation reaction conditions include at least: a temperature of 270-290°C and a pressure of less than 100 Pa. The inventors have found that under this preferred embodiment, the prepolymer can exhibit better polycondensation effect, thereby enhancing the modification effect of both the polyol and the monomer having the structure shown in formula (II) on the polyester.

[0053] According to a particularly preferred embodiment of the present invention, the method for preparing modified polyester includes the following steps:

[0054] (1) Under oxygen-isolated conditions, the polyol, isophthalic acid, dicarboxylic acid, aliphatic diol and antimony-containing catalyst shown in formula (IV) are mixed and the first stage reaction is carried out at a temperature of 200-260℃ and a pressure of 2.2-2.8MPa until the water output reaches the theoretical value, and the prepolymer is obtained.

[0055] Where m is a positive integer from 3 to 10;

[0056] (2) The first stage reaction system is released to normal pressure, and the temperature is gradually increased to enter the low vacuum stage. After the low vacuum time is about 45 minutes, the prepolymer is subjected to the second stage reaction at a temperature of 270-290℃ and a pressure of less than 100Pa until the stirring power reaches the rated value and the material is discharged.

[0057] The modified polyester provided by the present invention is mixed with polyvinyl chloride to form composite particles, which are further compounded with a toughening agent to form a sheet material. This composite material exhibits excellent toughness, cold resistance, and strength, and all performance tests show excellent results. Based on this, a third aspect of the present invention provides the application of the modified polyester described above and / or the modified polyester obtained by the above method in shoe sole materials.

[0058] A fourth aspect of the present invention provides a method for preparing a composite material, the method comprising the following steps:

[0059] S1. The modified polyester described above and / or the modified polyester obtained by the above method are mixed with polyvinyl chloride and additives, and then melt-blended to obtain composite particles.

[0060] S2. The composite particles are mixed with the toughening agent and then co-extruded and compounded.

[0061] In this invention, the additives can improve the mixing effect of modified polyester and polyvinyl chloride. Preferably, the additives contain zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate, and dioctyl phthalate. The toughening agent can improve the impact resistance of the composite material. Preferably, the toughening agent is selected from at least one of polybutylene succinate, polyethylene succinate, polycaprolactone, and polybutylene adipate, more preferably polybutylene succinate.

[0062] According to the present invention, preferably, the modified polyester and polyvinyl chloride are mixed at a weight ratio of 1:0.5-2, and simultaneously additives such as zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate, and dioctyl phthalate are added, followed by melt mixing to obtain composite particles. The inventors have found that this preferred embodiment is beneficial for improving the strength and toughness of the composite material, better meeting the performance requirements of shoe sole materials.

[0063] According to the present invention, by way of example, the weight ratio of modified polyester, polyvinyl chloride, zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate, dioctyl phthalate and toughening agent is 1:0.8-1.2:0.01-0.05:0.02-0.08:0.02-0.08:0.01-0.05:0.02-0.08:0.2-0.3.

[0064] In this invention, the melt-blending process of modified polyester with polyvinyl chloride and additives, as well as the co-extrusion blending process of composite particles with toughening agents, can both be carried out using conventional equipment, such as a twin-screw extruder. Exemplarily, after mixing modified polyester with polyvinyl chloride and additives, the mixture is heated to 90-110°C and held for 25-35 minutes to obtain a mixture. This mixture is then plasticized and melt-extruded in a twin-screw extruder to obtain composite particles. At this time, the extruder's main motor speed is 150-250 r / min, the pressure is 10-15 MPa, and the operating temperature is as follows: from the feed port to the die, zone 1 temperature 100-120°C, zone 2 temperature 130-140°C, zone 3 temperature 140-150°C, and zone 4 temperature 150-160°C. After extrusion, stretching, cooling, pelletizing, and drying, the composite particles are obtained. Further, the composite particles and toughening agents are co-extruded and blended in the screw extruder to extrude the composite material. The thickness of the composite material (sheet) can be greater than or equal to 1 cm.

[0065] The sheet material prepared by the above method has excellent toughness, cold resistance and strength, and the performance test results are excellent, making it suitable for the production and manufacturing of shoe soles.

[0066] The present invention will be described in detail below through embodiments.

[0067] In the following embodiments, the detection methods for each parameter and performance are as follows:

[0068] (1) Bending test - The sample size is 20×20cm. Fold it once in the horizontal direction and once in the vertical direction to check for breakage. Repeat the test 10 times for 10 samples. If one breaks, it is considered unqualified.

[0069] (2) Impact resistance test - The test shall be conducted in accordance with the method in ASTM-D3763 Standard Test Method for High-Speed ​​Puncture Performance of Plastics Using Load and Displacement Sensors. Each batch shall consist of 10 samples. If the average value is less than 250 kg / mm, it shall be considered unqualified.

[0070] (3) ROSS room temperature bending (23℃) and cold bending (-10℃) test - The test is conducted according to the method in "ASTM-D1052 Ross bending test". The maximum number of room temperature bending tests is 75,000, and the maximum number of cold bending tests is 25,000. The sample is considered unqualified if there is cracking or breakage at the center cut of the sample.

[0071] (4) The melting point shall be tested according to Method A (microscopic method) of 5.3.1 in GB / T 14190-2008 "Test Methods for Fiber Grade Polyester Chips (PET)".

[0072] (5) The glass transition temperature was calculated by differential scanning calorimetry (DSC). The specific process was as follows: under nitrogen protection, DSC thermal analysis was used to raise the temperature from 25℃ to 290℃ at a rate of 10℃ / min and hold it for 5min. Then, the temperature was lowered to 25℃ at a rate of 400℃ / min. Then, the temperature was raised from 25℃ to 290℃ at a rate of 10℃ / min and held for 5min. Finally, the temperature was lowered to 100℃ at a rate of 10℃ / min. The glass transition temperature Tg was calculated based on the second heating curve.

[0073] (6) The intrinsic viscosity was tested according to method 5.1 in GB / T14190-2017 Test Method for Fiber Grade Polyester Chips.

[0074] (7) The terminal carboxyl group was tested according to method 5.4 in GB / T14190-2017 Test Method for Fiber Grade Polyester Chips.

[0075] In the following examples, unless otherwise specified, the raw materials and reagents used are all conventional commercial products; atmospheric pressure refers to a gauge pressure of 0.

[0076] Example 1

[0077] Add 3.5 kg of terephthalic acid (PAT), 1.5 kg of isophthalic acid, 3 kg of ethylene glycol, 11 g of the polyol shown in formula (V), and 3 g of antimony glycol to a 20 L reactor.

[0078]

[0079] Esterification was carried out at a temperature of 230℃ and a pressure (gauge pressure) of 2.5MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 280℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0080] Example 2

[0081] Add 3 kg of terephthalic acid (PAT), 2 kg of isophthalic acid, 3 kg of ethylene glycol, 57 g of the polyol shown in formula (V), and 3 g of antimony trioxide to a 20 L reactor.

[0082] Esterification was carried out at a temperature of 230℃ and a pressure (gauge pressure) of 2.5MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 280℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0083] Example 3

[0084] Add 2 kg of terephthalic acid (PAT), 3 kg of isophthalic acid, 3 kg of ethylene glycol, 47 g of the polyol shown in formula (V), linear condensate of resorcinol and formaldehyde (A), and 3 g of antimony glycol to a 20 L reactor.

[0085] Esterification was carried out at a temperature of 230℃ and a pressure (gauge pressure) of 2.5MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 280℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0086] Example 4

[0087] Add 2.5 kg of terephthalic acid (PAT), 2.5 kg of isophthalic acid, 3 kg of ethylene glycol, 35 g of the polyol shown in formula (VI), and 3 g of antimony glycol to a 20 L reactor.

[0088]

[0089] Esterification was carried out at a temperature of 220℃ and a pressure (gauge pressure) of 2.6MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 270℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0090] Example 5

[0091] Add 2.7 kg of terephthalic acid (PAT), 2.3 kg of isophthalic acid, 3 kg of ethylene glycol, 25 g of the polyol shown in formula (VII), and 3 g of antimony glycol to a 20 L reactor.

[0092]

[0093] Esterification was carried out at a temperature of 260℃ and a pressure (gauge pressure) of 2.1MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 290℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0094] Example 6

[0095] The modified polyester was prepared according to the method of Example 3, except that the amount of polyol shown in formula (V) was replaced with 100g.

[0096] Example 7

[0097] The modified polyester was prepared according to the method of Example 3, except that the amount of antimony glycol was replaced with 15g.

[0098] Example 8

[0099] The modified polyester was prepared according to the method of Example 3, except that antimony glycolate was replaced with tetrabutyl titanate.

[0100] Example 9

[0101] The modified polyester was prepared according to the method of Example 3, except that the polyol shown in formula (V) was replaced with the polyol shown in formula (VIII).

[0102]

[0103] Comparative Example 1

[0104] Add 2.5 kg of terephthalic acid (PAT), 2.5 kg of isophthalic acid, 3 kg of ethylene glycol, and 3 g of antimony glycol to a 20 L reactor. Esterification is carried out at a temperature of 220 °C and a pressure (gauge pressure) of 2.6 MPa. When the water output reaches the theoretical value, esterification is stopped, the pressure is released to atmospheric pressure, and stirring is continued for 10 min. The temperature is gradually increased to enter the low vacuum stage. After about 45 min of low vacuum, the high vacuum polycondensation stage (pressure < 100 Pa) is entered. Polycondensation is carried out at a temperature of 270 °C. When the stirring power reaches the rated value, the material is discharged to obtain modified polyester.

[0105] Comparative Example 2

[0106] Add 4.4 kg of terephthalic acid (PAT), 0.6 kg of isophthalic acid, 3 kg of ethylene glycol, 47 g of the polyol shown in formula (V), and 3 g of antimony glycol to a 20 L reactor;

[0107] Esterification was carried out at a temperature of 230℃ and a pressure (gauge pressure) of 2.5MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 280℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0108] Comparative Example 3

[0109] Add 5 kg of terephthalic acid (PAT), 3 kg of ethylene glycol, 47 g of the polyol shown in formula (V), and 3 g of antimony glycol to a 20 L reactor.

[0110] Esterification was carried out at a temperature of 230℃ and a pressure (gauge pressure) of 2.5MPa. When the water output reached the theoretical value, esterification was stopped, the pressure was released to normal, and stirring was continued for 10 minutes. The temperature was gradually increased to enter the low vacuum stage. After about 45 minutes of low vacuum, the high vacuum polycondensation stage (pressure <100Pa) was entered. Polycondensation was carried out at a temperature of 280℃. When the stirring power reached the rated value, the material was discharged to obtain the modified polyester.

[0111] Test Example 1

[0112] The contents of structural unit A (as shown in Formula (I), molar amount of structural unit B (as shown in Formula (II), molar amount of structural unit C (as shown in Formula (III)) and metal element content in the modified polyesters prepared in Examples 1-9 and Comparative Examples 1-3 are shown in Table 1. Structural unit A was obtained by infrared and nuclear magnetic resonance detection analysis, and the molar amounts of structural unit B and structural unit C were determined by gas chromatography.

[0113] Table 1

[0114]

[0115] Test Example 2

[0116] The melting point, glass transition temperature, intrinsic viscosity, and terminal carboxyl groups of the modified polyesters prepared in Examples 1-9 and Comparative Examples 1-3 were tested. The results are shown in Table 2.

[0117] Table 2

[0118] serial number Melting point, °C Glass transition temperature, °C Intrinsic viscosity, dL / g Terminal carboxyl group content, mol / t Example 1 125.6 65.2 0.762 28 Example 2 120.2 63.3 0.782 23.6 Example 3 110.7 60.5 0.795 33 Example 4 116.5 62.3 0.765 28 Example 5 118.2 62.0 0.776 24.6 Example 6 107.9 61.2 0.789 33.8 Example 7 110.6 60.4 0.793 34.5 Example 8 110.5 60.4 0.797 20.6 Example 9 110.3 60.8 0.789 32 Comparative Example 1 118.7 60.0 0.785 25 Comparative Example 2 225.0 70.3 0.753 22.4 Comparative Example 3 253.9 78.2 0.745 22.8

[0119] Test Example 3

[0120] The modified polyesters obtained in Examples 1-9 and Comparative Examples 1-3 were used to prepare composite sheets for use as shoe sole materials with polyvinyl chloride (PVC). The specific method was as follows: 5 kg of modified polyester was mixed evenly with 5 kg of PVC, 0.1 kg of zinc oxide, 0.2 kg of epoxy resin, 0.2 kg of triethyl phosphate, 0.1 kg of dibutyltin dilaurate, and 0.2 kg of dioctyl phthalate. The mixture was then heated to 100°C and held at that temperature for 30 minutes to obtain a final mixture. The material is melted and extruded in a twin-screw extruder. The extruder main unit speed is 200 r / min, the pressure is 12 MPa, and the operating temperature is as follows: from the feed port to the die head, the temperature of zone 1 is 110℃, the temperature of zone 2 is 135℃, the temperature of zone 3 is 145℃, and the temperature of zone 4 is 155℃. After extrusion, drawing, cooling, pelletizing, and drying, composite particles are obtained. The dried composite particles are co-extruded and compounded with 1.2 kg of toughening agent polybutylene adipate in the screw extruder to form a composite board with a thickness of 1.5 cm.

[0121] The composite boards corresponding to Examples 1-9 and Comparative Examples 1-3 were subjected to flexural endurance tests, impact tests, and ROSS room temperature flexural (23℃) and cold flexural (-10℃) tests. The results are shown in Table 3.

[0122] Table 3

[0123]

[0124] The modified polyester provided by this invention has a low melting point, which can be reduced to about 110°C, and the composite board made by blending it with PVC has excellent toughness and impact resistance, and can be used as a material for shoe production.

[0125] 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 modified polyester, characterized in that, The modified polyester has a melting point of less than or equal to 130°C. The modified polyester and polyvinyl chloride are melt-blended at a weight ratio of 1:0.5-2 to form composite particles. Then, the modified polyester and toughening agent are co-extruded and blended at a weight ratio of 1:0.1-0.15 to form a composite board with a thickness of 1-2 cm. The impact resistance of the composite board is above 390 kg / mm. The modified polyester 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). (I), (II), (III), where R I R II R1, R2, R3, R4, R5, R6, R7 and R8 are each independently hydrogen or C1-C4 alkyl, and n is a positive integer from 4 to 11; The content of structural unit A shown in formula (I) of the modified polyester is less than or equal to 1% by weight, and the molar amount of structural unit B accounts for 30-60% of the total molar amount of structural unit B and structural unit C.

2. The modified polyester according to claim 1, characterized in that, The melting point of the modified polyester is less than or equal to 120°C; The modified polyester has a glass transition temperature of 60-70℃, an intrinsic viscosity of 0.7-0.85 dL / g, and a terminal carboxyl group content of 20-35 mol / t.

3. The modified polyester according to claim 1 or 2, characterized in that, R I R II R1, R2, R3, R4, R5, R6, R7, and R8 are each independently hydrogen or methyl; The content of structural unit A shown in formula (I) of the modified polyester is 0.1-1 by weight.

4. The modified polyester according to claim 1 or 2, characterized in that, R1, R2, R3, R4, R5, R6, R7, and R8 are hydrogen.

5. The modified polyester according to claim 1 or 2, characterized in that, The modified polyester contains antimony or titanium. The modified polyester contains less than or equal to 0.05% by weight of antimony or titanium.

6. The modified polyester according to claim 5, characterized in that, The modified polyester contains less than or equal to 0.03% by weight of antimony or titanium.

7. A method for preparing a modified polyester, characterized in that, Includes the following steps: (1) Under esterification reaction conditions, the modified monomer, diacid monomer, diol monomer and catalyst are mixed and the first stage reaction is carried out to obtain the prepolymer. (2) Under polycondensation reaction conditions, the prepolymer is subjected to a second-stage reaction; The modified monomer contains a polyol having the structure shown in formula (I) and a monomer having the structure shown in formula (II), wherein the diacid monomer is an acid or ester having the structure shown in formula (III). (I)， (II), (III), where R I R II R1, R2, R3, R4, R5, R6, R7 and R8 are each independently hydrogen or C1-C4 alkyl, and n is a positive integer from 4 to 11; The molar amount of the monomer having the structure shown in formula (II) accounts for 30-60% of the total molar amount of the monomer and the dicarboxylic acid monomer.

8. The preparation method according to claim 7, characterized in that, R I R II R1, R2, R3, R4, R5, R6, R7 and R8 are each independently hydrogen or methyl.

9. The preparation method according to claim 8, characterized in that, R1, R2, R3, R4, R5, R6, R7, and R8 are hydrogen.

10. The preparation method according to claim 7, characterized in that, The diol monomer is an aliphatic diol; The catalyst is an antimony-containing catalyst or a titanium-containing catalyst; Based on the total amount of the modified monomer, dicarboxylic acid monomer, diol monomer and catalyst, the amount of the polyol is less than or equal to 1 wt%.

11. The preparation method according to claim 10, characterized in that, The catalyst is selected from antimony glycolate, antimony acetate, antimony trioxide, titanium glycolate, nano titanium dioxide, or tetrabutyl titanate.

12. The preparation method according to any one of claims 7 to 11, characterized in that, In step (1), the esterification reaction conditions include at least: oxygen isolation, temperature of 200-260℃, and pressure of 2.2-2.8MPa; In step (2), the polycondensation reaction conditions include at least the following: temperature of 270-290℃ and pressure of less than 100Pa.

13. The use of the modified polyester according to any one of claims 1 to 6 and / or the modified polyester prepared by the method according to any one of claims 7 to 12 in shoe sole materials.

14. A method for preparing a composite material, characterized in that, The method includes the following steps: S1. The modified polyester according to any one of claims 1 to 6 and / or the modified polyester prepared by the method according to any one of claims 7 to 12 are mixed with polyvinyl chloride and additives, and then melt-blended to obtain composite particles. S2. The composite particles are mixed with a toughening agent and then co-extruded and compounded. The additives contain zinc oxide, epoxy resin, triethyl phosphate, dibutyltin dilaurate, and dioctyl phthalate. The toughening agent is selected from at least one of polybutylene succinate, polyethylene succinate, polycaprolactone, and polybutylene adipate.

Images