High-heat-resistance polyester synthesized by isocyanate functionalized isosorbide and preparation method of high-heat-resistance polyester

Abstract

The invention relates to high-heat-resistance polyester synthesized by isocyanate functionalized isosorbide and a preparation method of the high-heat-resistance polyester, and belongs to the technical field of polyester materials. The heat distortion temperature of the high-heat-resistance polyester synthesized by the isocyanate functionalized isosorbide is 91 DEG C or above, and the chromaticity b value is 0-8. The method provided by the invention can effectively solve the problem that isosorbide is easy to oxidize and turn yellow at high temperature due to low activity of terminal hydroxyl groups, and meanwhile, the conversion efficiency of isosorbide is effectively improved, so that the prepared copolyester has higher heat-resistant temperature without influencing the color of the material. The product is not easy to oxidize and turn yellow at high temperature. Functionalized isosorbide is introduced to a polyester main chain, the rigid molecular structure greatly increases the heat resistance of the polyester material, a large number of hydrogen bonds can be formed among generated carbamate bonds, and the heat resistance of the material can also be effectively improved.

Description

Technical Field

[0001] The invention relates to a high-heat-resistant polyester synthesized from isocyanate-functionalized isosorbide and a preparation method thereof, belonging to the technical field of polyester materials. Background Art

[0002] With the increasing depletion of petroleum resources and the deterioration of the environment, the development of bio-based polymer materials with renewable raw materials and environmentally friendly has urgent practical significance. Isosorbide, also known as 1,4:3,6-dianhydro-D-glucitol, is derived from sorbitol by two-step dehydration. As the only sugar diol that has achieved large-scale industrial production, isosorbide has the advantages of abundant raw material sources, rigidity and non-toxicity, and has been often used to prepare or modify polymer materials in recent years.

[0003] Aromatic polyesters have excellent mechanical properties, processing properties, chemical stability and low prices, and have been widely used in various fields. Introducing the structural unit of isosorbide-type polyester into aromatic polyesters can not only improve the heat resistance of the material, but also give the material a certain degree of biodegradability, thereby better meeting the requirements for its wide application in industry.

[0004] Existing isosorbide copolyesters are prepared by directly esterifying isosorbide with acid and diol. For example, CN107955142A contains a method for preparing isosorbide polyester; CN109134834_A contains a method for preparing isosorbide copolyester; CN109134834A contains a method for preparing isosorbide copolyester.

[0005] However, the activity of the two hydroxyl groups on isosorbide is much lower than that of other competing aliphatic diols such as ethylene glycol, so isosorbide is not effectively esterified during the esterification step. After entering the polycondensation stage, isosorbide will be extracted from the system under high temperature and high vacuum conditions, resulting in a low conversion rate of isosorbide. At the same time, the isosorbide remaining in the system is also easily oxidized and yellowed. How to overcome the low reactivity of the secondary hydroxyl group of isosorbide and better introduce the isosorbide polyester structural unit into the aromatic polyester is the key to preparing high-performance isosorbide-based copolyesters. Summary of the invention

[0006] The first object of the present invention is to provide a highly heat-resistant polyester synthesized from isocyanate-functionalized isosorbide.

[0007] To achieve the first object of the present invention, the heat deformation temperature of the isocyanate functionalized isosorbide synthesized high heat-resistant polyester is above 91° C. and the chromaticity b value is between 0 and 8.

[0008] In one embodiment, the isocyanate functionalized isosorbide is used to synthesize a high heat resistant polyester. gValue above 105℃, T d5％ Value above 401℃.

[0009] In a specific embodiment, the isocyanate functionalized isosorbide synthesized high heat resistant polyester is prepared by the following method:

[0010] A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide;

[0011] B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product;

[0012] C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester;

[0013] The amount of isosorbide added is 0-10% of the total amount of diols, preferably 0.5-1%.

[0014] The structure of isocyanate functionalized isosorbide generated by the reaction of isophorone diisocyanate and isosorbide is shown in Formula 1:

[0015]

[0016] The inert atmosphere is an atmosphere that does not react with the reaction system, such as nitrogen.

[0017] In a specific embodiment, the molar ratio of isophorone diisocyanate to isosorbide is 1.5-2.5:1.

[0018] In a specific embodiment, the reaction temperature of step A is 70-100° C., and the reaction time is 25-40 min.

[0019] In a specific embodiment, the catalyst is at least one of tin-based, antimony-based, zinc-based or titanium-based catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate.

[0020] In a specific embodiment, the temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa;

[0021] Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:1;

[0022] The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol;

[0023] The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol;

[0024] The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0-2.0:1.

[0025] In a specific embodiment, an auxiliary agent is further added to the polycondensation reaction in step C, and the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant;

[0026] Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

[0027] The second object of the present invention is to provide a method for preparing the above-mentioned isocyanate functionalized isosorbide to synthesize high heat-resistant polyester.

[0028] To achieve the second object of the present invention, the method comprises:

[0029] A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide;

[0030] B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product;

[0031] C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester;

[0032] The amount of isosorbide added is 0-10% of the total amount of diols and is not 0, preferably 0.5-1%.

[0033] In one specific embodiment, the molar ratio of isophorone diisocyanate to isosorbide is 1.5 to 2.5:1;

[0034] The reaction temperature of step A is preferably 70-100°C, and the reaction time is 25-40 min;

[0035] The catalyst is preferably at least one of tin, antimony, zinc or titanium catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate;

[0036] Preferably, the temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa;

[0037] Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:1;

[0038] The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol;

[0039] The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol;

[0040] The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0 to 2.0:1;

[0041] Preferably, an auxiliary agent is further added to the polycondensation reaction in step C, and the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant;

[0042] Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

[0043] Beneficial effects:

[0044] 1. The method of the present invention can effectively solve the problem that the terminal hydroxyl group of isosorbide has low activity and is easily oxidized and yellowed at high temperature, and at the same time effectively improves the conversion efficiency of isosorbide, so that the prepared copolyester has a higher heat resistance temperature without affecting the color of the material.

[0045] 2. The product of the present invention is not easy to oxidize and turn yellow at high temperature. Functionalized isosorbide is introduced into the polyester main chain, and the rigid molecular structure greatly increases the heat resistance of the polyester material, and a large number of hydrogen bonds are formed between the generated carbamate bonds, which can also effectively improve the heat resistance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1This is the H NMR spectrum of the copolyester material prepared in Example 1 of the present invention.

[0047] Figure 2 This is the nuclear magnetic hydrogen spectrum of the copolyester material prepared in Comparative Example 1 of the present invention.

[0048] Figure 3 This is the H NMR spectrum of the copolyester material prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0049] To achieve the first object of the present invention, the heat deformation temperature of the isocyanate functionalized isosorbide synthesized high heat-resistant polyester is above 91° C. and the chromaticity b value is between 0 and 8.

[0050] In one embodiment, the isocyanate functionalized isosorbide is used to synthesize a high heat resistant polyester. g Value above 105℃, T d5％ Value above 401℃.

[0051] In a specific embodiment, the isocyanate functionalized isosorbide synthesized high heat resistant polyester is prepared by the following method:

[0052] A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide;

[0053] B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product;

[0054] C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester;

[0055] The amount of isosorbide added is 0-10% of the total amount of diols, preferably 0.5-1%.

[0056] In a specific embodiment, the molar ratio of isophorone diisocyanate to isosorbide is 1.5-2.5:1.

[0057] In a specific embodiment, the reaction temperature of step A is 70-100° C., and the reaction time is 25-40 min.

[0058] In a specific embodiment, the catalyst is at least one of tin-based, antimony-based, zinc-based or titanium-based catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate.

[0059] In a specific embodiment, the temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa;

[0060] Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:1;

[0061] The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol;

[0062] The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol;

[0063] The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0-2.0:1.

[0064] In a specific embodiment, an auxiliary agent is further added to the polycondensation reaction in step C, and the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant;

[0065] Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

[0066] To achieve the second object of the present invention, the method comprises:

[0067] A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide;

[0068] B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product;

[0069] C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester;

[0070] The amount of isosorbide added is 0-10% of the total amount of diols, preferably 0.5-1%.

[0071] In one specific embodiment, the molar ratio of isophorone diisocyanate to isosorbide is 1.5 to 2.5:1;

[0072] The reaction temperature of step A is preferably 70-100°C, and the reaction time is 25-40 min;

[0073] The catalyst is preferably at least one of tin, antimony, zinc or titanium catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate;

[0074] Preferably, the temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa;

[0075] Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:1;

[0076] The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol;

[0077] The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol;

[0078] The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0 to 2.0:1;

[0079] Preferably, a small amount of auxiliary agent is also added to the polycondensation reaction in step C, and the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant;

[0080] Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

[0081] The specific implementation modes of the present invention are further described below in conjunction with embodiments, but the present invention is not limited to the scope of the embodiments.

[0082] Example 1

[0083] (1) Under a nitrogen atmosphere, isophorone diisocyanate and treated isosorbide are added to a reactor and reacted under the action of a catalyst, dibutyltin dilaurate, wherein the molar ratio of isophorone diisocyanate to isosorbide is 2:1, dibutyltin dilaurate accounts for 300 ppm of the total amount of isosorbide and isophorone diisocyanate, the temperature is set to 80°C, the reaction time is 30 minutes, and isocyanate functionalized isosorbide is generated.

[0084] (2) After the above reaction is completed, terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, and n-butyl titanate are continuously added to the reactor under nitrogen atmosphere, the molar ratio of diol to dibasic acid is 1.3:1, the molar ratio of isosorbide, ethylene glycol and 1,4-cyclohexanedimethanol in diol is 0.5:2.5:7, and n-butyl titanate accounts for 600ppm of the total amount of terephthalic acid, isosorbide, ethylene glycol, isophorone diisocyanate, and 1,4-cyclohexanedimethanol. N2 is replaced and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0085] (3) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280 ° C, and the material is discharged after the polycondensation reaction for 3 hours.

[0086] Example 2

[0087] (1) Under a nitrogen atmosphere, isophorone diisocyanate and treated isosorbide are added to a reactor and reacted under the action of a catalyst, dibutyltin dilaurate, wherein the molar ratio of isophorone diisocyanate to isosorbide is 2:1, dibutyltin dilaurate accounts for 300 ppm of the total amount of isosorbide and isophorone diisocyanate, the temperature is set to 80°C, the reaction time is 30 minutes, and isocyanate functionalized isosorbide is generated.

[0088] (2) After the above reaction is completed, terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, and n-butyl titanate are continuously added to the reactor under nitrogen atmosphere, the molar ratio of diol to dibasic acid is 1.3:1, the molar ratio of isosorbide, ethylene glycol and 1,4-cyclohexanedimethanol in diol is 1:2.5:6.5, and n-butyl titanate accounts for 600ppm of the total amount of terephthalic acid, isosorbide, ethylene glycol, isophorone diisocyanate and 1,4-cyclohexanedimethanol. N2 is replaced and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0089] (3) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280 ° C, and the material is discharged after the polycondensation reaction for 3 hours.

[0090] Example 3

[0091] (1) Under a nitrogen atmosphere, isophorone diisocyanate and treated isosorbide are added to a reactor and reacted under the action of a catalyst, dibutyltin dilaurate, wherein the molar ratio of isophorone diisocyanate to isosorbide is 2:1, dibutyltin dilaurate accounts for 300 ppm of the total amount of isosorbide and isophorone diisocyanate, the temperature is set to 80°C, the reaction time is 30 minutes, and isocyanate functionalized isosorbide is generated.

[0092] (2) After the above reaction is completed, terephthalic acid, isophthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, and n-butyl titanate are continuously added to the reactor under nitrogen atmosphere, the molar ratio of diol to dibasic acid is 1.3:1, wherein the molar ratio of terephthalic acid to isophthalic acid in dibasic acid is 9:1, the molar ratio of isosorbide, ethylene glycol and 1,4-cyclohexanedimethanol in diol is 0.5:2.5:7, and n-butyl titanate accounts for 600ppm of the total amount of terephthalic acid, isophthalic acid, isosorbide, ethylene glycol, isophorone diisocyanate, and 1,4-cyclohexanedimethanol. N2 is substituted and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4 hours, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0093] (3) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280 ° C, and the material is discharged after the polycondensation reaction for 3 hours.

[0094] Example 4

[0095] (1) Under a nitrogen atmosphere, isophorone diisocyanate and treated isosorbide are added to a reactor and reacted under the action of a catalyst, dibutyltin dilaurate, wherein the molar ratio of isophorone diisocyanate to isosorbide is 2:1, dibutyltin dilaurate accounts for 300 ppm of the total amount of isosorbide and isophorone diisocyanate, the temperature is set to 80°C, the reaction time is 30 minutes, and isocyanate functionalized isosorbide is generated.

[0096] (2) After the above reaction is completed, terephthalic acid, isophthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, and n-butyl titanate are continuously added to the reactor under nitrogen atmosphere, the molar ratio of diol to dibasic acid is 1.3:1, wherein the molar ratio of terephthalic acid to isophthalic acid in dibasic acid is 9:1, the molar ratio of isosorbide, ethylene glycol and 1,4-cyclohexanedimethanol in diol is 1:2.5:6.5, and n-butyl titanate accounts for 600ppm of the total amount of terephthalic acid, isophthalic acid, isosorbide, ethylene glycol, isophorone diisocyanate, and 1,4-cyclohexanedimethanol. N2 is substituted and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0097] (3) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280 ° C, and the material is discharged after the polycondensation reaction for 3 hours.

[0098] Comparative Example 1

[0099] (1) Under nitrogen atmosphere, terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, and n-butyl titanate are added to a reactor, the molar ratio of diol to dibasic acid is 1.3:1, the molar ratio of ethylene glycol to 1,4-cyclohexanedimethanol in diol is 2.5:7.5, and n-butyl titanate accounts for 600ppm of the total feed amount. N2 is replaced and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0100] (2) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280°C, and the material is discharged after the polycondensation reaction for 3 hours.

[0101] The nuclear magnetic hydrogen spectrum of the copolyester material prepared in Comparative Example 1 is as follows Figure 1 shown.

[0102] Comparative Example 2

[0103] (1) Under nitrogen atmosphere, terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, isosorbide, and n-butyl titanate are added to a reactor, the molar ratio of diol to dibasic acid is 1.3:1, the molar ratio of isosorbide, ethylene glycol, and 1,4-cyclohexanedimethanol in diol is 0.5:2.5:7, and n-butyl titanate accounts for 600ppm of the total feed amount. N2 is replaced and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0104] (2) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280°C, and the material is discharged after the polycondensation reaction for 3 hours.

[0105] The nuclear magnetic hydrogen spectrum of the copolyester material prepared in Comparative Example 2 is as follows Figure 2 shown.

[0106] Comparative Example 3

[0107] (1) Under nitrogen atmosphere, terephthalic acid, ethylene glycol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and n-butyl titanate are added to a reactor, the molar ratio of diol to dibasic acid is 1.3:1, the molar ratio of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, ethylene glycol, and 1,4-cyclohexanedimethanol in diol is 2:2.5:5.5, and n-butyl titanate accounts for 600ppm of the total feed amount. N2 is replaced and the pressure is increased to 0-0.1MPa. The temperature in the reactor is set at 235°C and the esterification reaction is stirred for 4h, and the pressure is maintained at 0.25-0.3MPa to generate a prepolymer.

[0108] (2) After the esterification is completed, the pressure is slowly released to 0 MPa, and the ethylene glycol solution prepared with the heat stabilizer is added to the kettle body. The amount of heat stabilizer added is 25 ppm of the total feed amount, and vacuum polycondensation is carried out. The vacuum process is divided into two stages: low vacuum and high vacuum. In the low vacuum stage, the vacuum degree is controlled at more than 200 Pa, and in the high vacuum stage, the vacuum degree is controlled within 80 Pa. The temperature in the kettle is set at 280°C, and the material is discharged after the polycondensation reaction for 3 hours.

[0109] The test results of the above comparative examples and embodiments are shown in Table 1.

[0110] Table 1 Test results of comparative examples and embodiments

[0111] <![CDATA[T g (℃)]]> <![CDATA[T d5％ (℃)]]> Heat deformation temperature(℃) Chroma (b value) Comparative Example 1 90.7 403.4 80.1 3.4 Comparative Example 2 107.6 402.3 91.2 21.7 Comparative Example 3 105.6 401.8 90.8 3.6 Example 1 108.4 401.7 94.4 5.3 Example 2 121.3 402.1 106.5 7.7 Example 3 105.9 402.3 91.3 5.1 Example 4 117.5 401.6 101.7 7.4

[0112] According to the data analysis in Table 1, the copolyester synthesized by isocyanate-functionalized isosorbide in the present invention has a higher glass transition temperature and excellent heat resistance. In particular, the color of the copolyester synthesized after modification is greatly improved compared with the copolyester synthesized by directly adding isosorbide, and the b value can be within 8, which can meet the use requirements in the fields of spinning, film blowing, packaging, billboards, etc.

Claims

1. Synthesis of high heat-resistant polyester by isocyanate-functionalized isosorbide, characterized in that: The heat deformation temperature of the isocyanate functionalized isosorbide synthesized high heat-resistant polyester is above 91° C., and the chromaticity b value is between 0 and 8.

2. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 1, characterized in that: The isocyanate functionalized isosorbide is used to synthesize high heat resistant polyester g Value above 105℃, T d5％ Value above 401℃.

3. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 1 or 2, characterized in that: The isocyanate functionalized isosorbide synthesized high heat-resistant polyester is prepared by the following method: A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide; B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product; C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester; The amount of isosorbide added is 0-10% of the total amount of diols and is not 0, preferably 0.5-1%.

4. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 3, characterized in that: The molar ratio of isophorone diisocyanate to isosorbide is 1.5-2.5:

1.

5. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 3, characterized in that: The reaction temperature of step A is 70-100° C., and the reaction time is 25-40 min.

6. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 3, characterized in that: The catalyst is at least one of tin-based, antimony-based, zinc-based or titanium-based catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate.

7. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 3, characterized in that: The temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa; Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:

1. The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol; The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol; The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0-2.0:

1.

8. The method for synthesizing high heat-resistant polyester from isocyanate-functionalized isosorbide according to claim 3, characterized in that: In step C, an auxiliary agent is further added to the polycondensation reaction, wherein the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant; Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

9. The method for preparing high heat-resistant polyester by isocyanate-functionalized isosorbide according to any one of claims 1 to 8, characterized in that: The method comprises: A. Under the action of a catalyst, isophorone diisocyanate reacts with isosorbide to form isocyanate functionalized isosorbide; B. subjecting the isocyanate-functionalized isosorbide to an esterification reaction with terephthalic acid and an aliphatic diol under an inert gas atmosphere and a catalyst to obtain a first intermediate product; C. subjecting the first intermediate product to a polycondensation reaction to obtain an isosorbide-based copolyester; The amount of isosorbide added is 0-10% of the total amount of diols, preferably 0.5-1%.

10. The method for preparing high heat-resistant polyester by isocyanate-functionalized isosorbide according to claim 9, characterized in that: The molar ratio of isophorone diisocyanate to isosorbide is 1.5 to 2.5:1; The reaction temperature of step A is preferably 70-100°C, and the reaction time is 25-40 min; The catalyst is preferably at least one of tin, antimony, zinc or titanium catalysts; the mass of the catalyst in step A is preferably 100 to 1000 ppm of the total mass of isosorbide and isophorone diisocyanate; Preferably, the temperature of the esterification reaction in step B is 230°C to 250°C, the time of the esterification reaction is 3 to 4 hours, and the pressure of the esterification reaction is 0.25 to 0.3 MPa; Preferably, isophthalic acid is further added in the reaction in step B, and the molar ratio of terephthalic acid to isophthalic acid is 1 to 20:1; The aliphatic diol in step B is preferably at least one of ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol or 1,8-octanediol; The mass of the catalyst in step B is preferably 200 to 1000 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol; The molar ratio of the added amount of the diol to the dibasic acid is preferably 1.0 to 2.0:1; Preferably, an auxiliary agent is further added to the polycondensation reaction in step C, and the amount of the auxiliary agent added is preferably 20 to 200 ppm of the total mass of isosorbide, isophorone diisocyanate, terephthalic acid and aliphatic diol, and the auxiliary agent preferably includes a heat stabilizer and an antioxidant; Preferably, the temperature of the polycondensation reaction is 270-300° C., the time of the polycondensation reaction is 2-3 hours, and the vacuum degree of the polycondensation reaction is 0.1 Pa-200 Pa.

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