Preparation method of tertiary amine modified rapidly degradable polyester

Abstract

The invention belongs to the technical field of copolymerization modification of degradable polyester, and discloses a preparation method of tertiary amine modified rapidly degradable polyester, which comprises the following steps: in the presence of a catalyst and an auxiliary agent, carrying out esterification, pre-polycondensation and polycondensation on tertiary amine, dibasic acid and dihydric alcohol to prepare the tertiary amine modified rapidly degradable polyester, the structural formula of the tertiary amine is RN (CH2CH2OH) 2, R is a side group, and the side group at least contains one hydroxyl group. The preparation method is simple and easy to implement, the prepared tertiary amine modified rapidly degradable polyester can be hydrolyzed, the mass loss within 49 days can reach 3-20%, especially hydrolysis can be further accelerated after oxidation treatment, and meanwhile the breaking strength of copolyester is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of biodegradable polyester copolymer modification, and relates to a preparation method of a tertiary amine-modified polyester that can be rapidly degraded. Background Art

[0002] The development of biodegradable polyester products is of great significance for alleviating plastic pollution. However, current biodegradable polyester products, such as PBAT, PBS, PBST, etc., degrade extremely slowly in the natural environment and can only be degraded under controlled composting conditions. However, controlled composting seriously occupies land resources and does not conform to the future development trend.

[0003] To improve the degradation performance of the above-mentioned biodegradable polyester products, there are various modification methods:

[0004] 1) Introducing easily degradable segments: For example, in the patents with the authorized announcement numbers CN113736073B and CN114573965B and the patent application with the published application number CN118562108A, an ether-containing monomer (such as diglycolic acid) is introduced into the polyester molecular chain. By constructing a high-density ether bond, the hydrophilicity of the copolyester is greatly enhanced, enabling the copolyester to achieve rapid hydrolysis; the patent application with the published application number CN119591852A discloses a PBAT-PLA copolyester and its preparation method. This method introduces a PLA segment into PBAT to improve the degradation performance of the copolyester by utilizing the easy degradability of the PLA segment;

[0005] 2) Blending with easily degradable components: For example, in the patent applications with the published application numbers CN119661999A, CN119432034A, CN119350825A, and CN119639199A, PBAT is blended and modified with PLA to prepare various products, improving the application performance of the original polyester;

[0006] 3) Introducing a molecular switch for controlled degradation: For example, the patent application with the patent application number CN114507329A discloses a pH-responsive controllable degradation polyurethane and its preparation method. This method enables the product to rapidly break bonds in an acidic environment. However, the heat resistance of the silyl ether bond is poor and it is easily decomposed above 180°C, which does not meet the polymerization process requirements of common polyesters and can only be chain-extended with isocyanate.

[0007] In summary, although there are various methods for the degradation modification of biodegradable polyesters in the prior art and they all have certain effects. However, there are also some main problems as follows:

[0008] (1) Regarding the introduction of easily degradable segments: By introducing diglycolic acid and lactic acid components, this method can enhance the hydrophilicity of the copolyester well, accelerate the degradation performance, and achieve rapid hydrolysis. However, as flexible segments, diglycolic acid and lactic acid will inevitably disrupt the regular molecular chain structure of the copolyester and reduce the breaking strength of the copolyester. It is not advisable to enhance the degradation performance at the expense of strength.

[0009] (2) Regarding the blending of easily degradable components: Although the blending modification process of this method is simple and low-cost, and can also achieve toughening and strengthening, the compatibility between multiple components is the first problem to be solved. In addition, although the easily degradable components can degrade rapidly in the initial stage of degradation, they do not change the original molecular chain structure of the copolyester, and have limited effect on improving the degradation performance of the copolyester.

[0010] (3) Regarding the introduction of molecular switches for controlled degradation: Although this method can achieve the controlled degradation of polyesters, it can well maintain the mechanical properties of the copolyester during use and can also be rapidly degraded after special treatment after being discarded. However, the special treatment conditions of molecular switches are sometimes relatively harsh. For example, the environment of strong acid or strong base is highly corrosive to equipment. In addition, due to their special functions, molecular switches often introduce special compounds, which are costly or have complex preparation processes, are not conducive to large-scale preparation, and the safety of degradation products also needs to be further verified.

[0011] Therefore, it is of great significance to study a preparation method of a tertiary amine-modified rapidly degradable polyester to solve the above problems. Summary of the Invention

[0012] The purpose of the present invention is to solve the problems existing in the prior art and provide a preparation method of a tertiary amine-modified rapidly degradable polyester.

[0013] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0014] A preparation method of a tertiary amine-modified rapidly degradable polyester, in the presence of a catalyst and an auxiliary agent, a tertiary amine, a dibasic acid and a diol are subjected to esterification, pre-polycondensation and polycondensation reactions to obtain a tertiary amine-modified rapidly degradable polyester;

[0015] The tertiary amine is a polyhydroxy tertiary amine compound, and the structural formula is RN(CH 2 CH 2 OH) 2 , where R is a side group, and the side group contains at least one hydroxyl group;

[0016] The addition amount of the tertiary amine is 0.3 - 1.2% of the molar content of the dibasic acid. When the addition amount is low, the catalytic effect of the tertiary amine is insufficient. When the addition amount is too high, a crosslinked network is easily formed, which will limit the processing application of the material in a rheological field mainly dominated by stretching;

[0017] In a 60°C aqueous environment, the tertiary amine-modified rapidly degradable polyester can undergo hydrolysis, with a mass loss of 3.2 - 20% in 49 days;

[0018] After oxidation treatment of the tertiary amine-modified rapidly degradable polyester, the number-average molecular weight decreases by 3 - 40%. Oxidation treatment refers to immersion in a 30 wt% hydrogen peroxide solution at 30°C for 8 hours;

[0019] After the tertiary amine-modified rapidly degradable polyester is subjected to oxidation treatment and then treated in a 60°C aqueous environment, the mass loss is 11.3 - 40% in 49 days.

[0020] In the present invention, the dibasic acid can also be replaced with an esterified product of the dibasic acid, and similar effects can also be obtained.

[0021] In the present invention, a polyhydroxy tertiary amine is used for copolymer modification of the polyester. To ensure the reaction, the number of hydroxyl functional groups must be greater than or equal to 2. However, polyhydroxy tertiary amines with 2 functional groups, such as N-methyldiethanolamine and N-ethyldiethanolamine, are extremely prone to oxidative degradation at high temperatures (150°C) and do not meet the polyester polymerization process. After screening, it is found that polyhydroxy tertiary amines (hydroxyl ≥ 3) have good thermal stability and can be used for polyester copolymer modification.

[0022] On the one hand, the tertiary amine contains lone pair electrons, which can enhance the hydrophilicity of the copolyester. In addition, the tertiary amine is weakly basic in aqueous solution. For example, the pH value of a 1 mol% triethanolamine aqueous solution at 25°C is 10.5 - 11.5. Constructing a weakly basic environment in the copolyester molecular chain can catalyze the cleavage of ester bonds near the tertiary amine and accelerate degradation; on the other hand, although branching will limit the degradation rate of the copolyester, when the tertiary amine is close to unstable groups (such as ester bonds, and the hydroxyl group in the tertiary amine forms an ester bond after an esterification reaction), a cope elimination reaction can occur at a significantly lower temperature. After the tertiary amine is oxidized, β-H can directly undergo an elimination reaction to generate hydroxylamine and olefins, destroying the branched structure and accelerating degradation.

[0023] In addition, the tertiary amine used in the present invention contains multiple hydroxyl functional groups. The polyhydroxy structure can form a branched network during the polymerization process, increasing molecular chain entanglement, thereby enhancing the melt viscosity and improving the processability; the branched entanglement can also slightly enhance the breaking strength of the copolyester.

[0024] As a preferred technical solution:

[0025] For the preparation method of a tertiary amine-modified rapidly degradable polyester as described above, the tertiary amine is triethanolamine or bis(2-hydroxyethyl)amino(tris(hydroxymethyl))methane, preferably triethanolamine.

[0026] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the dibasic acid is dibasic acid I, or a mixed acid of dibasic acid I and dibasic acid II. Dibasic acid I is one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. Dibasic acid II is terephthalic acid. The molar percentage of dibasic acid I in the dibasic acid is 50-60% or 100%. The diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol.

[0027] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the molar ratio of the dibasic acid to the diol is 1:1.1-1.3.

[0028] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the catalyst is tetrabutyl titanate or antimony glycolate, and the catalyst addition amount is 300-1000 ppm of the mass of the dibasic acid.

[0029] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the additives are a heat stabilizer and an anti-ether agent. The heat stabilizer is triphenyl phosphate or triphenyl phosphite, and the anti-ether agent is sodium acetate anhydrous. The addition amounts of both the heat stabilizer and the anti-ether agent are 300-1000 ppm of the mass of the dibasic acid.

[0030] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the esterification temperature is 160-220 °C, the esterification pressure is 0.1-0.6 MPa, and the end condition of esterification is that the water output exceeds 95% of the theoretical value.

[0031] The pre-polycondensation temperature is 180-240 °C, the pre-polycondensation time is 0.5-1.5 h, and the pre-polycondensation pressure is 1-10 kPa.

[0032] The polycondensation temperature is 200-260 °C, the polycondensation pressure ≤ 80 Pa, and the polycondensation time is 1-3 h. The introduction of the tertiary amine can rapidly shorten the polycondensation time.

[0033] A preparation method of a tertiary amine-modified rapidly degradable polyester as described in any one of the above, wherein the intrinsic viscosity of the tertiary amine-modified rapidly degradable polyester is 1.06-1.20 dL / g, the number average molecular weight is greater than 30000 g / mol, the colorimetric value b is 3-10, and the static water contact angle is 72°-80.5°.

[0034] A preparation method of a tertiary amine-modified rapidly degradable polyester as described above, wherein the breaking strength of the tertiary amine-modified rapidly degradable polyester is 14.0-34.2 MPa, which is slightly improved compared with that without tertiary amine modification.

[0035] Beneficial effects:

[0036] (1) The tertiary amine used in the present invention contains lone pairs of electrons, which can effectively improve the hydrophilicity of the enhanced copolyester. At the same time, the tertiary amine shows weak alkalinity in aqueous solution and can also catalyze the cleavage of ester bonds near the tertiary amine, accelerating degradation. In addition, after the tertiary amine is oxidized, β-H can directly undergo an elimination reaction to generate hydroxylamine and olefins, destroying the branched structure and accelerating degradation.

[0037] (2) The tertiary amine adopted in the present invention contains multiple hydroxyl functional groups. The multi-hydroxyl structure can form a branched network during the polymerization process, increasing the entanglement of molecular chains, thereby enhancing the melt viscosity and improving the processability; the branched entanglement can also slightly enhance the breaking strength of the copolyester. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a mechanical property curve graph of commercial PBAT of the present invention and the tertiary amine-modified rapidly degradable polyester prepared in Examples 1-2;

[0039] Figure 2 It is a schematic diagram of the hydrophilicity of commercial PBAT of the present invention and the tertiary amine-modified rapidly degradable polyester prepared in Examples 1-2;

[0040] Figure 3 It is a schematic diagram of the degradation performance of commercial PBAT of the present invention and the tertiary amine-modified rapidly degradable polyester prepared in Examples 1-2 in a neutral water environment. DETAILED DESCRIPTION OF THE INVENTION

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0042] The test methods for relevant performance indicators in the following examples and comparative examples are as follows:

[0043] Intrinsic viscosity: The tertiary amine-modified rapidly degradable polyester prepared in each example was used as a sample, and then the intrinsic viscosity of the sample was measured with reference to the standard of GB / T 14190-2017 "Test Methods for Fiber Grade Polyester (PET) Chips".

[0044] Colorimetric value b: The tertiary amine-modified rapidly degradable polyester prepared in each example was used as a sample, and then the colorimetric value b of the sample was measured with reference to the standard of GB / T 17931-2018 "Polyethylene Terephthalate (PET) Resin for Bottles".

[0045] Tensile strength: The tertiary amine-modified rapidly degradable polyesters prepared in each example were used as samples, and then the tensile strength of the samples was determined with reference to the ISO 527 standard "Plastics - Determination of tensile properties".

[0046] Mass loss: The tertiary amine-modified rapidly degradable polyesters prepared in each example were used as samples, and then the samples were hot-pressed into films with dimensions of 10 mm × 10 mm × 0.3 mm. Subsequently, the films were immersed in PBS buffer solution at 60 °C (pH = 7.2, bath ratio = 1:125) for 49 days of degradation. At the same time, the mass changes of the samples before and after degradation were recorded, and the mass loss was calculated.

[0047] Example 1

[0048] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0049] (1) Preparation of raw materials;

[0050] Tertiary amine: Triethanolamine;

[0051] Dicarboxylic acid: A mixed acid of 1,6-hexanedioic acid and terephthalic acid, and the molar percentage of 1,6-hexanedioic acid in the dicarboxylic acid is 50%;

[0052] Diol: 1,4-butanediol;

[0053] Catalyst: Tetrabutyl titanate;

[0054] Heat stabilizer: Triphenyl phosphite;

[0055] Anti-ether agent: Sodium acetate anhydrous;

[0056] (2) The tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer, and anti-ether agent were mixed evenly and then subjected to an esterification reaction under the conditions of a pressure of 0.2 MPa and a temperature of 200 °C until the water output exceeded 95% of the theoretical value, and then the esterification reaction was terminated; among them, the addition amount of the tertiary amine was 0.5% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol was 1:1.2, the addition amount of the catalyst was 500 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer was 500 ppm of the mass of the dicarboxylic acid, and the addition amount of the anti-ether agent was 500 ppm of the mass of the dicarboxylic acid;

[0057] (3) The product after the esterification reaction in step (2) was pre-polycondensed at a temperature of 240 °C and a pressure of 5 kPa for 1 h, and then polycondensed at a temperature of 260 °C and a pressure of 50 Pa for 1.8 h to obtain the tertiary amine-modified rapidly degradable polyester.

[0058] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.15 dL / g, the number-average molecular weight is 58667 g / mol, the colorimetric value b is 7.6, the static water contact angle is 79.9°, and the breaking strength is 21 MPa;

[0059] In a water environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester after 49 days is 7.6%;

[0060] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreases by 12.7%;

[0061] After soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester is then treated in a water environment at 60 °C, and the mass loss after 49 days is 14.7%.

[0062] Example 2

[0063] A preparation method of a tertiary amine-modified rapidly degradable polyester is basically the same as that of Example 1, except that: in step (2), the addition amount of the tertiary amine is 1% of the molar content of the dibasic acid, and in step (3), the polycondensation time is 1.4 h.

[0064] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.15 dL / g, the number-average molecular weight is 62893 g / mol, the colorimetric value b is 8.2, the static water contact angle is 76.8°, and the breaking strength is 19.6 MPa;

[0065] In a water environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester after 49 days is 3.9%;

[0066] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreases by 20.8%;

[0067] After soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester is then treated in a water environment at 60 °C, and the mass loss after 49 days is 18.8%.

[0068] The mechanical properties, hydrophilicity and degradation properties of the tertiary amine-modified rapidly degradable polyesters prepared in Examples 1-2 and commercial PBAT (manufacturer: BASF, grade: ecoflex C1200) were compared, and the results are as Figures 1 to 3 shown. It can be seen from the figure that compared with commercial PBAT, the tertiary amine-modified rapidly degradable polyesters prepared in Examples 1-2 can enhance the breaking strength and hydrolysis performance of the copolyester after introducing triethanolamine.

[0069] Example 3

[0070] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0071] (1) Preparation of raw materials;

[0072] Tertiary amine: triethanolamine;

[0073] Dicarboxylic acid: a mixed acid of 1,4-butanedioic acid and terephthalic acid, and the molar percentage of 1,4-butanedioic acid in the dicarboxylic acid is 50%;

[0074] Diol: 1,4-butanediol;

[0075] Catalyst: tetrabutyl titanate;

[0076] Heat stabilizer: triphenyl phosphate;

[0077] Ether-proof agent: anhydrous sodium acetate;

[0078] (2) After mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and ether-proof agent evenly, carry out an esterification reaction under the conditions of a pressure of 0.3 MPa and a temperature of 220 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; among them, the addition amount of the tertiary amine is 0.8% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.15, the addition amount of the catalyst is 600 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 800 ppm of the mass of the dicarboxylic acid, and the addition amount of the ether-proof agent is 500 ppm of the mass of the dicarboxylic acid;

[0079] (3) Pre-polycondense the product after the esterification reaction in step (2) for 1.5 h under the conditions of a temperature of 230 °C and a pressure of 1 kPa, and then polycondense for 2 h under the conditions of a temperature of 255 °C and a pressure of 80 Pa to obtain the tertiary amine-modified rapidly degradable polyester.

[0080] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.06 dL / g, the number-average molecular weight is 51891 g / mol, the colorimetric b value is 8.9, the water static contact angle is 79.1°, and the breaking strength is 25.8 MPa;

[0081] In a 60 °C water environment, the mass loss of the tertiary amine-modified rapidly degradable polyester in 49 days is 3%;

[0082] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreases by 18.4%;

[0083] After soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester is then treated in a 60 °C water environment, and the mass loss in 49 days is 17.5%.

[0084] Example 4

[0085] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0086] (1)Preparation of raw materials;

[0087] Tertiary amine: triethanolamine;

[0088] Dicarboxylic acid: composed of succinic acid and adipic acid with a molar ratio of 1:1;

[0089] Diol: 1,4-butanediol;

[0090] Catalyst: tetrabutyl titanate;

[0091] Heat stabilizer: triphenyl phosphate;

[0092] Anti-ether agent: anhydrous sodium acetate;

[0093] (2)After mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and anti-ether agent evenly, carry out an esterification reaction under the conditions of a pressure of 0.3 MPa and a temperature of 180 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; among them, the addition amount of the tertiary amine is 1% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.2, the addition amount of the catalyst is 800 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 400 ppm of the mass of the dicarboxylic acid, and the addition amount of the anti-ether agent is 400 ppm of the mass of the dicarboxylic acid;

[0094] (3)Pre-polycondense the product after the esterification reaction in step (2) for 1.5 h under the conditions of a temperature of 200 °C and a pressure of 3 kPa, and then polycondense for 1.6 h under the conditions of a temperature of 220 °C and a pressure of 70 Pa to obtain a tertiary amine-modified rapidly degradable polyester.

[0095] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.09 dL / g, the number average molecular weight is 53875 g / mol, the colorimetric value b is 5.9, the static water contact angle is 76.1°, and the breaking strength is 17.6 MPa;

[0096] In a 60 °C water environment, the mass loss of the tertiary amine-modified rapidly degradable polyester in 49 days is 12.8%;

[0097] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number average molecular weight decreases by 25.1%;

[0098] After being treated by soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in an aqueous environment at 60 °C, and the mass loss was 33.1% after 49 days.

[0099] Example 5

[0100] A preparation method of a tertiary amine-modified rapidly degradable polyester comprises the following steps:

[0101] (1) Preparation of raw materials;

[0102] Tertiary amine: triethanolamine;

[0103] Dicarboxylic acid: 1,4-butanedioic acid;

[0104] Diol: 1,4-butanediol;

[0105] Catalyst: tetrabutyl titanate;

[0106] Heat stabilizer: triphenyl phosphite;

[0107] Anti-ether agent: sodium acetate anhydrous;

[0108] (2) After mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and anti-ether agent evenly, carry out an esterification reaction under the conditions of a pressure of 0.1 MPa and a temperature of 160 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; wherein, the addition amount of the tertiary amine is 1.2% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.2, the addition amount of the catalyst is 1000 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 300 ppm of the mass of the dicarboxylic acid, and the addition amount of the anti-ether agent is 300 ppm of the mass of the dicarboxylic acid;

[0109] (3) Carry out pre-polycondensation on the product after the esterification reaction in step (2) for 0.5 h under the conditions of a temperature of 180 °C and a pressure of 6 kPa, and then carry out polycondensation for 1.3 h under the conditions of a temperature of 210 °C and a pressure of 30 Pa to obtain the tertiary amine-modified rapidly degradable polyester.

[0110] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.17 dL / g, the number-average molecular weight is 63675 g / mol, the colorimetric value b is 3, the static water contact angle is 74.9°, and the breaking strength is 34.2 MPa;

[0111] In an aqueous environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester is 5.7% after 49 days;

[0112] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreased by 25.8%;

[0113] After being treated by soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in a water environment at 60 °C, and the mass loss was 20.2% after 49 days.

[0114] Example 6

[0115] A preparation method of a tertiary amine-modified rapidly degradable polyester comprises the following steps:

[0116] (1) Preparation of raw materials;

[0117] Tertiary amine: Triethanolamine;

[0118] Dicarboxylic acid: 1,10-Decanedioic acid;

[0119] Diol: 1,6-Hexanediol;

[0120] Catalyst: Antimony glycolate;

[0121] Heat stabilizer: Triphenyl phosphate;

[0122] Ether-proofing agent: Sodium acetate anhydrous;

[0123] (2) After uniformly mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and ether-proofing agent, carry out an esterification reaction under the conditions of a pressure of 0.2 MPa and a temperature of 200 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; wherein, the addition amount of the tertiary amine is 1.2% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.25, the addition amount of the catalyst is 500 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 700 ppm of the mass of the dicarboxylic acid, and the addition amount of the ether-proofing agent is 700 ppm of the mass of the dicarboxylic acid;

[0124] (3) Pre-polycondense the product after the esterification reaction in step (2) for 1.5 h under the conditions of a temperature of 220 °C and a pressure of 10 kPa, and then polycondense for 1.1 h under the conditions of a temperature of 230 °C and a pressure of 60 Pa to obtain the tertiary amine-modified rapidly degradable polyester.

[0125] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.15 dL / g, the number-average molecular weight is 57345 g / mol, the colorimetric b value is 5.7, the static water contact angle is 72°, and the breaking strength is 14 MPa;

[0126] In a water environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester is 20% after 49 days;

[0127] After the tertiary amine-modified rapidly degradable polyester is soaked in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreases by 36.8%;

[0128] After being treated by soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in a water environment at 60 °C, and the mass loss was 40% after 49 days.

[0129] Example 7

[0130] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0131] (1) Preparation of raw materials;

[0132] Tertiary amine: Triethanolamine;

[0133] Dicarboxylic acid: 1,5-Pentanedioic acid;

[0134] Diol: Ethylene glycol;

[0135] Catalyst: Antimony glycolate;

[0136] Heat stabilizer: Triphenyl phosphite;

[0137] Ether inhibitor: Sodium acetate anhydrous;

[0138] (2) After mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and ether inhibitor evenly, carry out an esterification reaction under the conditions of a pressure of 0.6 MPa and a temperature of 180 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; wherein, the addition amount of the tertiary amine is 0.5% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.1, the addition amount of the catalyst is 300 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 300 ppm of the mass of the dicarboxylic acid, and the addition amount of the ether inhibitor is 300 ppm of the mass of the dicarboxylic acid;

[0139] (3) Pre-polycondense the product after the esterification reaction in step (2) for 1 h under the conditions of a temperature of 200 °C and a pressure of 10 kPa, and then polycondense for 2 h under the conditions of a temperature of 210 °C and a pressure of 30 Pa to obtain the tertiary amine-modified rapidly degradable polyester.

[0140] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.08 dL / g, the number-average molecular weight is 50676 g / mol, the colorimetric value b is 5.4, the water static contact angle is 78.7°, and the breaking strength is 16.7 MPa;

[0141] In a water environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester is 15.4% after 49 days;

[0142] After soaking the tertiary amine-modified rapidly degradable polyester in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number-average molecular weight decreased by 20.1%;

[0143] After being treated by soaking in 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in an aqueous environment at 60 °C, and the mass loss was 27.8% after 49 days.

[0144] Example 8

[0145] A preparation method of a tertiary amine-modified rapidly degradable polyester comprises the following steps:

[0146] (1) Preparation of raw materials;

[0147] Tertiary amine: triethanolamine;

[0148] Dicarboxylic acid: 1,7-heptanedicarboxylic acid;

[0149] Diol: 1,3-propanediol;

[0150] Catalyst: tetrabutyl titanate;

[0151] Heat stabilizer: triphenyl phosphate;

[0152] Ether-proof agent: sodium acetate anhydrous;

[0153] (2) The tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and ether-proof agent are mixed evenly and then subjected to an esterification reaction under the conditions of a pressure of 0.6 MPa and a temperature of 200 °C until the water output exceeds 95% of the theoretical value, and then the esterification reaction ends; wherein, the addition amount of the tertiary amine is 1% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.2, the addition amount of the catalyst is 800 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 500 ppm of the mass of the dicarboxylic acid, and the addition amount of the ether-proof agent is 500 ppm of the mass of the dicarboxylic acid;

[0154] (3) The product after the esterification reaction in step (2) is pre-polycondensed at a temperature of 220 °C and a pressure of 1 kPa for 1 h, and then polycondensed at a temperature of 220 °C and a pressure of 60 Pa for 1.8 h to obtain the tertiary amine-modified rapidly degradable polyester.

[0155] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.12 dL / g, the number average molecular weight is 55545 g / mol, the colorimetric value b is 8.1, the water static contact angle is 75.9°, and the breaking strength is 15.4 MPa;

[0156] In an aqueous environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester is 16.8% after 49 days;

[0157] After the tertiary amine-modified rapidly degradable polyester is soaked in 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number average molecular weight decreases by 28.8%;

[0158] After being treated in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in an aqueous environment at 60 °C, and the mass loss was 34.2% after 49 days.

[0159] Example 9

[0160] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0161] (1) Preparation of raw materials;

[0162] Tertiary amine: Triethanolamine;

[0163] Dicarboxylic acid: A mixed acid of 1,8-octanedicarboxylic acid and terephthalic acid, and the molar percentage of 1,8-octanedicarboxylic acid in the dicarboxylic acid is 60%;

[0164] Diol: Ethylene glycol;

[0165] Catalyst: Antimony glycolate;

[0166] Heat stabilizer: Triphenyl phosphite;

[0167] Ether inhibitor: Sodium acetate anhydrous;

[0168] (2) After mixing the tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and ether inhibitor evenly, carry out an esterification reaction under the conditions of a pressure of 0.6 MPa and a temperature of 220 °C until the water output exceeds 95% of the theoretical value, and then end the esterification reaction; among them, the addition amount of the tertiary amine is 1.2% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.1, the addition amount of the catalyst is 300 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 300 ppm of the mass of the dicarboxylic acid, and the addition amount of the ether inhibitor is 300 ppm of the mass of the dicarboxylic acid;

[0169] (3) Pre-polycondense the product after the esterification reaction in step (2) for 1 h under the conditions of a temperature of 240 °C and a pressure of 5 kPa, and then polycondense for 1 h under the conditions of a temperature of 250 °C and a pressure of 40 Pa to obtain the tertiary amine-modified rapidly degradable polyester.

[0170] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.2 dL / g, the number average molecular weight is 66785 g / mol, the colorimetric value b is 10, the water static contact angle is 74°, and the breaking strength is 17.8 MPa;

[0171] In an aqueous environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester after 49 days is 10.7%;

[0172] After the tertiary amine-modified rapidly degradable polyester is soaked in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the number average molecular weight decreases by 40%;

[0173] After being treated by soaking in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in a water environment at 60 °C, and the mass loss was 38.6% after 49 days.

[0174] Example 10

[0175] A preparation method of a tertiary amine-modified rapidly degradable polyester comprises the following steps:

[0176] (1) Preparation of raw materials;

[0177] Tertiary amine: bis(2-hydroxyethyl)amino(tris(hydroxymethyl))methane;

[0178] Dicarboxylic acid: dimethyl adipate;

[0179] Diol: 1,5-pentanediol;

[0180] Catalyst: tetrabutyl titanate;

[0181] Heat stabilizer: triphenyl phosphate;

[0182] Anti-ether agent: anhydrous sodium acetate;

[0183] (2) The tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and anti-ether agent are mixed evenly and then subjected to an esterification reaction under the conditions of a pressure of 0.6 MPa and a temperature of 220 °C until the water output exceeds 95% of the theoretical value, and then the esterification reaction ends; wherein, the addition amount of the tertiary amine is 0.3% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.3, the addition amount of the catalyst is 800 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 1000 ppm of the mass of the dicarboxylic acid, and the addition amount of the anti-ether agent is 1000 ppm of the mass of the dicarboxylic acid;

[0184] (3) The product after the esterification reaction in step (2) is pre-polycondensed at a temperature of 210 °C and a pressure of 3 kPa for 1 h, and then polycondensed at a polycondensation temperature of 220 °C and a polycondensation pressure of 40 Pa for 2.5 h to obtain the tertiary amine-modified rapidly degradable polyester.

[0185] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.08 dL / g, the number average molecular weight is 42757 g / mol, the colorimetric b value is 7.4, the water static contact angle is 80.5°, and the breaking strength is 15.2 MPa;

[0186] In a water environment at 60 °C, the mass loss of the tertiary amine-modified rapidly degradable polyester is 5.2% after 49 days;

[0187] The number-average molecular weight of the tertiary amine-modified rapidly degradable polyester decreased by 3.2% after being immersed in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h;

[0188] After being immersed in a 30 wt% hydrogen peroxide solution at 30 °C for 8 h, the treated tertiary amine-modified rapidly degradable polyester was further treated in an aqueous environment at 60 °C, and the mass loss was 11.3% after 49 days.

[0189] Example 11

[0190] A preparation method of a tertiary amine-modified rapidly degradable polyester is as follows:

[0191] (1) Preparation of raw materials;

[0192] Tertiary amine: bis(2-hydroxyethyl)amino(tris(hydroxymethyl)methane);

[0193] Dicarboxylic acid: a mixed acid of 1,9-nonanedioic acid and terephthalic acid, and the molar percentage of 1,9-nonanedioic acid in the dicarboxylic acid is 60%;

[0194] Diol: 1,4-butanediol;

[0195] Catalyst: tetrabutyl titanate;

[0196] Heat stabilizer: triphenyl phosphate;

[0197] Anti-ether agent: anhydrous sodium acetate;

[0198] (2) The tertiary amine, dicarboxylic acid, diol, catalyst, heat stabilizer and anti-ether agent are mixed evenly and then subjected to an esterification reaction under the conditions of a pressure of 0.2 MPa and a temperature of 200 °C until the water output exceeds 95% of the theoretical value, and then the esterification reaction is terminated; among them, the addition amount of the tertiary amine is 0.8% of the molar content of the dicarboxylic acid, the molar ratio of the dicarboxylic acid to the diol is 1:1.3, the addition amount of the catalyst is 800 ppm of the mass of the dicarboxylic acid, the addition amount of the heat stabilizer is 1000 ppm of the mass of the dicarboxylic acid, and the addition amount of the anti-ether agent is 1000 ppm of the mass of the dicarboxylic acid;

[0199] (3) The product after the esterification reaction in step (2) is pre-polycondensed at a temperature of 220 °C and a pressure of 8 kPa for 1.5 h, and then polycondensed at a temperature of 220 °C and a pressure of 50 Pa for 1.4 h to obtain the tertiary amine-modified rapidly degradable polyester.

[0200] The intrinsic viscosity of the finally obtained tertiary amine-modified rapidly degradable polyester is 1.10 dL / g, the number-average molecular weight is 48432 g / mol, the colorimetric value b is 9.5, the static water contact angle is 76.8°, and the breaking strength is 15.9 MPa;

[0201] In a 60°C water environment, the mass loss of the tertiary amine-modified rapidly degradable polyester is 14.2% after 49 days;

[0202] When the tertiary amine-modified rapidly degradable polyester is immersed in a 30 wt% hydrogen peroxide solution at 30°C for 8 h, the number-average molecular weight decreases by 20.2%;

[0203] After being immersed in a 30 wt% hydrogen peroxide solution at 30°C for 8 h and then treated in a 60°C water environment, the mass loss of the treated tertiary amine-modified rapidly degradable polyester is 29.7% after 49 days.

Claims

1. A method for preparing a tertiary amine-modified rapidly degradable polyester, characterized in that: In the presence of a catalyst and an auxiliary agent, tertiary amine, dibasic acid and diol are subjected to esterification, pre-polycondensation and polycondensation to obtain tertiary amine-modified fast-degradable polyester. The structural formula of tertiary amines is RN(CH2CH2OH)2, where R is a side group, and the side group contains at least one hydroxyl group; The amount of tertiary amine added is 0.3~1.2% of the molar content of the dibasic acid; The number average molecular weight of the tertiary amine-modified rapidly degradable polyester decreases by 3-40% after oxidation treatment, wherein the oxidation treatment refers to immersion in a 30 wt % hydrogen peroxide solution at 30° C. for 8 hours; The tertiary amine-modified rapidly degradable polyester is treated by oxidation and then in a 60° C. water environment, and the mass loss in 49 days is 11.3-40%.

2. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 1, characterized in that: The tertiary amine is triethanolamine or bis(2-hydroxyethyl)amino(trihydroxymethyl)methane.

3. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 1, characterized in that: The dibasic acid is dibasic acid I, or a mixed acid of dibasic acid I and dibasic acid II, dibasic acid I is one or more of 1,4-succinic acid, 1,5-pentanedioic acid, 1,6-hexanedioic acid, 1,7-heptanedioic acid, 1,8-octanedioic acid, 1,9-nonanediol and 1,10-decanedioic acid, dibasic acid II is terephthalic acid, and the molar percentage of dibasic acid I in the dibasic acid is 50-60% or 100%; the diol is ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol or 1,6-hexanediol.

4. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 3, characterized in that: The molar ratio of dibasic acid to diol is 1:1.1~1.

3.

5. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 1, characterized in that: The catalyst is tetrabutyl titanate or antimony glycol, and the amount of catalyst added is 300-1000ppm of the mass of the dibasic acid.

6. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 1, characterized in that: The auxiliary agents are heat stabilizer and anti-ether agent, the heat stabilizer is triphenyl phosphate or triphenyl phosphite, the anti-ether agent is anhydrous sodium acetate, and the addition amounts of the heat stabilizer and the anti-ether agent are both 300-1000ppm of the mass of the dibasic acid.

7. The method for preparing a tertiary amine modified rapidly degradable polyester according to claim 1, characterized in that: The esterification temperature is 160~220℃, the esterification pressure is 0.1~0.6MPa, and the esterification end condition is that the water output exceeds 95% of the theoretical value; The pre-condensation temperature is 180~240℃, the pre-condensation time is 1~2.5h, and the pre-condensation pressure is 1~10kPa; The polycondensation temperature is 200~260℃, the polycondensation pressure is ≤80Pa, and the polycondensation time is 1~3h.

8. The method for preparing a tertiary amine modified rapidly degradable polyester according to any one of claims 1 to 7, characterized in that: The intrinsic viscosity of the tertiary amine-modified rapidly degradable polyester is 1.06-1.20 dL / g, the number average molecular weight is greater than 30,000 g / mol, the color b value is 3-10, and the water static contact angle is 72°-80.5°.

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