Degradable glycolic acid copolyester and method for preparing degradable glycolic acid copolyester by using titanium catalyst
By using titanium glycolate catalyst for esterification and polycondensation reaction, the pollution and hydrolysis of heavy metal catalysts in the prior art were solved, and glycolate copolyesters with high compost degradation rate and good biodegradation performance were prepared, achieving green environmental protection and cost reduction effects.
Patent Information
- Application Number
- CN202410896286.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-05
- Publication Date
- 2024-12-06
AI Technical Summary
The existing catalysts of glycolic acid copolyesters contain heavy metals or are prone to hydrolysis, which leads to environmental pollution and high production costs, and is difficult to process and mold.
The esterification and polycondensation reaction was carried out using titanium glycolate catalyst, and the utilization rate of glycolate was improved by using its high affinity and stability to prepare copolyesters with good biodegradable properties.
It avoids heavy metal pollution, reduces production costs, improves the degradability and processability of the materials, and the copolyester prepared has high compost degradation rate and good biodegradation properties.
Smart Images
Figure BDA0004929046690000051 
Figure BDA0004929046690000061 
Figure BDA0004929046690000091
Abstract
Description
Technical Field
[0001] The invention relates to the field of polymer materials, in particular to a degradable glycolic acid copolyester and a method for preparing the same using a titanium catalyst. Background Art
[0002] Polymers, with their light weight, durability, and diverse physical and chemical properties, have brought tremendous development and convenience to the fields of textiles, packaging, and medical treatment. However, the large-scale use of polymers over the years has also caused an environmental crisis. With the advancement of science and technology and the promotion of the concept of sustainable development, society is increasingly concerned about environmental pollution. In this context, biodegradable materials that combine the advantages of renewability, degradability, and biocompatibility have gradually become a hot topic in material basic and application research. Polyester has the potential to replace traditional polymers due to its excellent thermal and mechanical properties. At the same time, due to the presence of ester groups, some polyester products can be composted, naturally degraded, or alkaline degraded, providing a practical solution to environmental pollution problems.
[0003] Polyglycolic acid (PGA for short, also known as polyhydroxyacetic acid) is an aliphatic polyester polymer material with the lowest carbon number per unit, a completely decomposable ester structure, and a fast degradation rate. PGA is a crystalline polymer with a simple linear structure and a zigzag contraction of the main chain skeleton. Due to the special crystal structure, strong intermolecular forces such as hydrogen bonds, and high crystallinity of PGA, it has good comprehensive properties and has attracted widespread attention. Compared with polylactic acid and polybutylene glycol succinate, polyglycolic acid has many outstanding properties: (1) high heat resistance, with a melting point of 220-230°C, the highest among currently used biodegradable polymer materials; (2) high strength and modulus, exceeding polyetheretherketone and polyphenylene sulfide high-performance engineering plastics, and significantly higher than traditional biodegradable materials such as polylactic acid; (3) fast degradation rate. Due to the high ester content and no hydrophobic substituents in polyglycolic acid, its degradation rate is significantly higher than that of common biodegradable polyester materials such as PBS and PLA.
[0004] However, PGA has high crystallinity and melting point, is difficult to process and is easy to degrade, which to some extent limits its application range. The introduction of a second monomer or a third monomer to copolymerize with glycolic acid is used to improve the mechanical properties and processability of PGA. The excellent degradable properties of PGA can also be used to make traditional non-degradable materials degradable or improve the degradability of materials.
[0005] CN102718955A discloses a poly (ethylene terephthalate-co-glycolate) copolyester and a preparation method thereof, wherein the copolyester is prepared and synthesized using heavy metal catalysts such as stannous chloride or antimony trioxide. However, heavy metal elements are highly toxic and difficult to degrade, and they will pollute the environment during the treatment process, threatening ecological stability and human health. CN103910860A and CN115403749A disclose a preparation method for glycolic acid copolyester, wherein catalysts such as tetrabutyl titanate or tetraisopropyl titanate are added in the esterification stage to prepare esterified polymers. The titanate catalyst has the problem of easy hydrolysis, and a catalyst needs to be added in the polycondensation stage for reaction. Summary of the invention
[0006] In view of the problem that the catalyst of glycolic acid copolyester contains heavy metals or is easily hydrolyzed, the present invention provides a degradable glycolic acid copolyester and a method for preparing the same using a titanium-based catalyst. The glycolic acid titanium catalyst is used for catalytic preparation. The glycolic acid titanium catalyst is green and eco-friendly, has high affinity for glycolic acid monomers, can improve the utilization rate of glycolic acid, and the obtained copolyester has good biodegradability.
[0007] The specific technical scheme of the present invention is: The method for preparing degradable glycolic acid copolyester using a titanium catalyst comprises the following steps: (1) putting a polyester raw material and a titanium glycolate catalyst into a reactor for esterification reaction to obtain an esterified product; the polyester raw material includes glycolic acid and a base; (2) subjecting the above esterified product to polycondensation with a stabilizer and an antioxidant to obtain a degradable glycolic acid copolyester.
[0008] The invention mixes glycolic acid, aliphatic moieties or aromatic moieties and glycolic acid titanium catalyst to carry out esterification reaction, and after the esterification reaction, adds stabilizer and antioxidant to carry out polycondensation reaction to obtain degradable glycolic acid copolyester.
[0009] Preferably, the titanium glycolate catalyst is a mixture of one or more of the following structures: More preferably
[0010] The above-mentioned titanium glycolate catalyst has affinity for glycolic acid, can improve the reactivity of glycolic acid, improve the utilization of glycolic acid, and form esters. In addition, titanium glycolate has good hydrolysis resistance and will not be deactivated in the esterification reaction. It can continue to play a catalytic role in the subsequent polycondensation reaction, and the polymerization rate is stable and controllable.
[0011] Preferably, the amount of titanium glycolate catalyst added is: the amount of titanium element added is 5-15 ppm of the theoretical total polyester mass.
[0012] Preferably, the moiety is an aliphatic moiety; the conditions for the esterification reaction are: 160-180°C, 80-140 kPa nitrogen pressure for 2-5 hours; the conditions for the polycondensation reaction are: 190-230°C, absolute pressure below 100 Pa for 3-7 hours.
[0013] Preferably, the aliphatic moiety is one or more of lactic acid, caprolactone, glycolide and lactide; and the molar ratio of the aliphatic moiety to glycolic acid is 1:9-4:1.
[0014] Preferably, the unit is an aromatic unit, and the polyester raw material also includes ethylene glycol; the conditions for the esterification reaction are: reacting at 210-235°C and 100-200kPa nitrogen pressure for 2-4h; the conditions for the polycondensation reaction are: reacting at 240-265°C and an absolute pressure below 100Pa for 3-6h.
[0015] Preferably, the aromatic moiety is one or more of terephthalic acid, bis(hydroxymethyl) terephthalate, bis(hydroxyethyl) terephthalate, furandicarboxylic acid, bis(hydroxymethyl) furandicarboxylic acid, and bis(hydroxyethyl) furandicarboxylic acid; the molar ratio of the aromatic moiety to glycolic acid is 1:9-2:3; and the molar ratio of the aromatic moiety to ethylene glycol is 1:(1.1-1.3).
[0016] Preferably, the stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate, and triphenyl phosphate; the added amount of the stabilizer is 10-30 ppm of the theoretical total polyester mass.
[0017] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant THP-24, antioxidant 168, and antioxidant 1790; the added amount of the antioxidant is 50-300 ppm of the theoretical total polyester mass.
[0018] The present invention also provides a degradable glycolic acid copolyester prepared by the method for preparing degradable glycolic acid copolyester using a titanium catalyst, wherein the 180-day composting degradation rate is greater than 72.8%. The degradable glycolic acid copolyester has good product color, high intrinsic viscosity, and good biodegradability.
[0019] The beneficial effects produced by the present invention are: (1) The glycolic acid copolyester containing aliphatic units or the glycolic acid copolyester containing aromatic units prepared by the present invention is biodegradable. The use of glycolic acid titanium catalyst in the preparation process avoids the high toxicity and difficulty in degradation of heavy metal elements, does not cause pollution to the environment, is green and ecologically friendly, and is harmless to human health. The glycolic acid titanium catalyst has a stable structure, good water tolerance, and a stable and controllable polymerization rate. The structure of the glycolic acid ligand can improve the affinity of glycolic acid, increase the utilization rate of glycolic acid, and reduce production costs.
[0020] (2) The process conditions required for glycolic acid to react with different monomers are different. Different process conditions are used to obtain glycolic acid copolyesters or aromatic copolyesters containing aliphatic units through esterification and polycondensation. Under different process conditions, the glycolic acid titanium catalyst can exert a stable catalytic effect, improve the utilization rate of glycolic acid, and has strong adaptability. The prepared glycolic acid copolyesters or aromatic glycolic acid copolyesters containing aliphatic units have good hue, high intrinsic viscosity, and good biodegradability. DETAILED DESCRIPTION
[0021] The technical solution of the present invention is further described below through specific embodiments.
[0022] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the embodiments, unless otherwise specified, are all conventional methods in the art. Unless otherwise specified, parts are all weight parts, temperatures are expressed in ° C or at ambient temperature, and pressures are atmospheric pressure or near atmospheric pressure. There are many variations and combinations of reaction conditions (such as component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges) and conditions that can be used to optimize the purity and yield of the product obtained by the method, and only reasonable routine experiments will be required to optimize such method conditions.
[0023] Example The invention discloses a degradable glycolic acid copolyester, which is a glycolic acid copolyester containing aliphatic units or a glycolic acid copolyester containing aromatic units.
[0024] The preparation method of glycolic acid copolyester containing aliphatic units comprises the following steps: (A1) Glycolic acid, aliphatic moieties and a titanium glycolate catalyst are placed in a reaction vessel for esterification to obtain an esterified product. The aliphatic moieties are one or more of lactic acid, caprolactone, glycolide and lactide; the molar ratio of the aliphatic moieties to the glycolic acid is 1:9-4:1. The conditions for the esterification reaction are: reacting at 160-180° C. and 80-140 kPa nitrogen pressure for 2-5 hours; (A2) subjecting the esterified product to polycondensation with a stabilizer and an antioxidant to obtain a degradable glycolic acid copolyester. The polycondensation reaction is carried out at 190-230° C. and an absolute pressure of less than 100 Pa for 3-7 hours.
[0025] The method for preparing the glycolic acid copolyester containing aromatic moieties comprises the following steps: (B1) Glycolic acid, aromatic moiety, ethylene glycol and glycolate titanium catalyst are put into a reaction kettle for esterification reaction to obtain an esterified product. The aromatic moiety is one or more of terephthalic acid, bis(hydroxymethyl)terephthalate, bis(hydroxyethyl)terephthalate, furandicarboxylic acid, bis(hydroxymethyl)furandicarboxylic acid and bis(hydroxyethyl)furandicarboxylic acid; the molar ratio of the aromatic moiety to glycolic acid is 1:9-2:3; the molar ratio of the aromatic moiety to ethylene glycol is 1:(1.1-1.3). The conditions of the esterification reaction are: reaction at 210-235°C and 100-200 kPa nitrogen pressure for 2-4 hours.
[0026] (B2) subjecting the above esterified product, stabilizer and antioxidant to polycondensation reaction to obtain degradable glycolic acid copolyester. The polycondensation reaction conditions are: reacting at 240-265° C. and an absolute pressure lower than 100 Pa for 3-6 hours.
[0027] In the above preparation method, the titanium glycolate catalyst is a mixture of one or more of the following structures: The amount of titanium added is 5-15 ppm based on the theoretical total polyester mass.
[0028] The stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate and triphenyl phosphate; the added amount of the stabilizer is 10-30ppm of the theoretical total polyester mass.
[0029] The antioxidant is one or more of antioxidant 1010, antioxidant THP-24, antioxidant 168, and antioxidant 1790; the added amount of the antioxidant is 50-300ppm of the theoretical total polyester mass.
[0030] The present invention also provides the degradable glycolic acid copolyester prepared by the preparation method of the degradable glycolic acid copolyester. The degradable glycolic acid copolyester has good hue, high intrinsic viscosity and good biodegradability.
[0031] Example 1 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 4.5 mol of glycolic acid and 0.5 mol of lactic acid, as well as titanium glycolate in an amount of 7 ppm of the theoretical total polyester weight, were added to the polyester. The mixture was put into a reactor and subjected to esterification reaction at 160°C and 100 kPa under a nitrogen atmosphere for 4 hours to obtain an esterified product.
[0032] (2) Then, phosphoric acid in an amount of 20 ppm of the theoretical total polyester mass and antioxidant THP-24 in an amount of 50 ppm of the theoretical total polyester mass are mixed and added into the reactor, and a polycondensation reaction is carried out at 190° C. and 80 Pa under vacuum conditions for 5 hours to obtain a degradable glycolic acid copolyester.
[0033] Example 2 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 1 mol of glycolic acid, 3 mol of glycolide and 1 mol of lactic acid, and titanium glycolate in an amount of 5 ppm of the theoretical total polyester weight were added. Put it into a reactor and carry out esterification reaction at 175°C and 140 kPa under nitrogen atmosphere for 2 hours to obtain an esterified product; (2) Then, triethyl phosphate in an amount of 30 ppm of the theoretical total polyester mass and antioxidant 1790 in an amount of 100 ppm of the theoretical total polyester mass were mixed and added into the reactor, and polycondensation reaction was carried out at 225° C. and 40 Pa under vacuum conditions for 3 h to obtain degradable glycolic acid copolyester.
[0034] Example 3 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 2 mol of glycolic acid, 2 mol of caprolactone and 1 mol of lactide, and titanium glycolate in an amount of 15 ppm of the theoretical total polyester weight were added. Put it into a reactor, and carry out esterification reaction at 180°C and 80 kPa under nitrogen atmosphere for 5 hours to obtain an esterified product; (2) Then, trimethyl phosphate in an amount of 10 ppm of the theoretical total polyester mass and antioxidant 1010 in an amount of 300 ppm of the theoretical total polyester mass were mixed and added into the reactor, and a polycondensation reaction was carried out at 230° C. and 90 Pa under vacuum conditions for 7 hours to obtain a degradable glycolic acid copolyester.
[0035] Example 4 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 4.5 mol of glycolic acid, 0.4 mol of terephthalic acid, 0.1 mol of furandicarboxylic acid and 0.6 mol of ethylene glycol, and titanium glycolate in an amount of 9 ppm of the theoretical total polyester weight were added. Put it into a reactor and carry out esterification reaction at 210°C and 100 kPa in a nitrogen atmosphere for 4 hours to obtain an esterified product; (2) Then, triphenyl phosphate in an amount of 25 ppm of the theoretical total polyester mass and antioxidant 1010 and antioxidant 168 in an amount of 250 ppm of the theoretical total polyester mass were mixed and added into a reactor, and a polycondensation reaction was carried out at 240° C. and a vacuum condition of 50 Pa for 6 h to obtain a degradable glycolic acid copolyester.
[0036] Example 5 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 3.5 mol of glycolic acid, 1.5 mol of bis(hydroxymethyl) terephthalate, 1.65 mol of ethylene glycol, and titanium element were added in an amount of 10 ppm of glycolate titanium to the theoretical total polyester mass. Put it into a reactor and perform esterification reaction at 225°C and 150 kPa in a nitrogen atmosphere for 3 hours to obtain an esterified product; (2) Then, triphenyl phosphate in an amount of 15 ppm of the theoretical total polyester mass and antioxidant 1010 in an amount of 90 ppm of the total polyester mass were mixed and added into the reactor, and a polycondensation reaction was carried out at 250° C. and 40 Pa under vacuum conditions for 4 hours to obtain a degradable glycolic acid copolyester.
[0037] Example 6 A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 4 mol of glycolic acid, 1 mol of dihydroxyethyl terephthalate and 1.3 mol of ethylene glycol, and titanium glycolate in an amount of 8 ppm of the theoretical total polyester weight were added. Put it into a reactor and carry out esterification reaction at 235°C and 200 kPa in a nitrogen atmosphere for 2 h to obtain an esterified product; (2) Then, phosphoric acid and trimethyl phosphate in an amount of 25 ppm by weight of the theoretical total polyester and an antioxidant THP-24 in an amount of 300 ppm by weight of the theoretical total polyester were mixed and added into the reactor, and a polycondensation reaction was carried out at 265° C. and 30 Pa under vacuum conditions for 3 h to obtain a degradable glycolic acid copolyester.
[0038] Example 7 The difference from Example 4 is that the catalyst titanium glycolate is A mixture with a molar ratio of 1:1:1:2. Specifically: A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 4.5 mol of glycolic acid, 0.4 mol of terephthalic acid, 0.1 mol of furandicarboxylic acid and 0.6 mol of ethylene glycol, and 9 ppm of titanium element added to the theoretical total polyester weight were added to a reactor, and an esterification reaction was carried out at 210° C. and 100 kPa in a nitrogen atmosphere for 4 hours to obtain an esterified product; the glycolic acid titanium is The mixture was mixed in a molar ratio of 1:1:1:2.
[0039] (2) Then, triphenyl phosphate in an amount of 25 ppm of the theoretical total polyester mass and antioxidant 1010 and antioxidant 168 in an amount of 250 ppm of the theoretical total polyester mass were mixed and added into a reactor, and a polycondensation reaction was carried out at 240° C. and a vacuum condition of 50 Pa for 6 h to obtain a degradable glycolic acid copolyester.
[0040] Example 8 The difference from Example 4 is that the catalyst titanium glycolate is Specifically: A method for preparing degradable glycolic acid copolyester using a titanium catalyst, comprising the following steps: (1) 4.5 mol of glycolic acid, 0.4 mol of terephthalic acid, 0.1 mol of furandicarboxylic acid and 0.6 mol of ethylene glycol, and titanium glycolate in an amount of 9 ppm of the theoretical total polyester weight were added. The mixture was put into a reactor and subjected to esterification reaction at 210°C and 100 kPa in a nitrogen atmosphere for 4 hours to obtain an esterified product.
[0041] (2) Then, triphenyl phosphate in an amount of 25 ppm of the theoretical total polyester mass and antioxidant 1010 and antioxidant 168 in an amount of 250 ppm of the theoretical total polyester mass were mixed and added into a reactor, and a polycondensation reaction was carried out at 240° C. and a vacuum condition of 50 Pa for 6 h to obtain a degradable glycolic acid copolyester.
[0042] Comparative Example 1 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 4.5 mol of glycolic acid and 0.5 mol of lactic acid, as well as tetrabutyl titanate with a titanium element addition amount of 7 ppm of the theoretical total polyester weight, are put into a reactor, and an esterification reaction is carried out at 160° C. and 100 kPa in a nitrogen atmosphere for 4 hours to obtain an esterified product; (2) Then, phosphoric acid in an amount of 20 ppm of the theoretical total polyester mass and antioxidant THP-24 in an amount of 50 ppm of the theoretical total polyester mass are mixed and added into the reactor, and a polycondensation reaction is carried out at 190° C. and 80 Pa under vacuum conditions for 5 hours to obtain a degradable glycolic acid copolyester.
[0043] Comparative Example 2 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 1 mol of glycolic acid, 3 mol of glycolide and 1 mol of lactic acid, and titanium glycolate with a titanium element addition amount of 2 ppm of the theoretical total polyester weight are put into a reactor, and an esterification reaction is carried out at 175° C. and 140 kPa in a nitrogen atmosphere for 2 hours to obtain an esterified product; (2) Then, triethyl phosphate in an amount of 30 ppm of the theoretical total polyester mass and antioxidant 1790 in an amount of 100 ppm of the theoretical total polyester mass were mixed and added into the reactor, and polycondensation reaction was carried out at 225° C. and 40 Pa under vacuum conditions for 3 h to obtain degradable glycolic acid copolyester.
[0044] Comparative Example 3 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 2 mol of glycolic acid, 2 mol of caprolactone and 1 mol of lactide, as well as titanium glycolate with a titanium element addition amount of 15 ppm of the theoretical total polyester mass, are put into a reactor, and an esterification reaction is carried out at 180° C. and 80 kPa in a nitrogen atmosphere for 5 hours to obtain an esterified product; (2) Then, trimethyl phosphate in an amount of 10 ppm of the theoretical total polyester mass and antioxidant 1010 in an amount of 300 ppm of the theoretical total polyester mass were mixed and added into the reactor, and polycondensation reaction was carried out at 230° C. and 300 Pa under vacuum conditions for 7 h to obtain degradable glycolic acid copolyester.
[0045] Comparative Example 4 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 4.5 mol of glycolic acid, 0.4 mol of terephthalic acid, 0.1 mol of furandicarboxylic acid and 0.6 mol of ethylene glycol, and stannous octoate added in an amount of tin element equal to 9 ppm of the theoretical total polyester weight are added into a reactor, and an esterification reaction is carried out at 210° C. and 100 kPa in a nitrogen atmosphere for 4 hours to obtain an esterified product; (2) Then, triphenyl phosphate in an amount of 25 ppm of the theoretical total polyester mass and antioxidant 1010 and antioxidant 168 in an amount of 250 ppm of the theoretical total polyester mass were mixed and added into a reactor, and a polycondensation reaction was carried out at 240° C. and a vacuum condition of 50 Pa for 6 h to obtain a degradable glycolic acid copolyester.
[0046] Comparative Example 5 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 0.5 mol of glycolic acid, 4.5 mol of bis(hydroxymethyl) terephthalate, 4.95 mol of ethylene glycol, and titanium glycolate with a titanium element added in an amount of 10 ppm of the theoretical total polyester mass are put into a reaction kettle, and an esterification reaction is carried out at 225° C. and 150 kPa in a nitrogen atmosphere for 3 hours to obtain an esterified product; (2) Then, triphenyl phosphate in an amount of 15 ppm of the theoretical total polyester mass and antioxidant 1010 in an amount of 90 ppm of the total polyester mass were mixed and added into the reactor, and a polycondensation reaction was carried out at 250° C. and 40 Pa under vacuum conditions for 4 hours to obtain a degradable glycolic acid copolyester.
[0047] Comparative Example 6 A method for degrading glycolic acid copolyester, comprising the following steps: (1) 4 mol of glycolic acid, 1 mol of dihydroxyethyl terephthalate, 1.3 mol of ethylene glycol, and titanium glycolate with an addition amount of titanium element equal to 8 ppm of the theoretical total polyester weight are put into a reaction kettle, and esterification reaction is carried out at 245° C. and 200 kPa in a nitrogen atmosphere for 2 hours to obtain an esterified product; (2) Then, phosphoric acid and trimethyl phosphate in an amount of 25 ppm by weight of the theoretical total polyester and an antioxidant THP-24 in an amount of 300 ppm by weight of the theoretical total polyester were mixed and added into the reactor, and a polycondensation reaction was carried out at 265° C. and 30 Pa under vacuum conditions for 3 h to obtain a degradable glycolic acid copolyester.
[0048] Performance Testing The chemical structure, intrinsic viscosity, glass transition temperature (Tg), melting point (Tm) and 180-day composting degradation rate of the copolyesters prepared in Examples 1-6 and Comparative Examples 1-7 were tested respectively. The results are shown in Table 1.
[0049] The chemical structure was tested using a 600MHz nuclear magnetic resonance spectrometer produced by Brucker, Switzerland, to obtain the glycolic acid content in glycolic acid copolyester; the intrinsic viscosity was tested using an Ouster viscometer; the Tg and Tm were tested using a differential scanning calorimeter; and the 180-day composting degradation rate was tested according to GB / T 19277.2-2013.
[0050] Table 1. Statistical table of test results of degradable glycolic acid copolyester From the data in Table 1, we can see that: (1) In the esterification stage, a titanium glycolate catalyst having a titanium content of 7 ppm based on the theoretical total polyester mass is added. Compared with the glycolic acid copolyester prepared using tetrabutyl titanate as a catalyst (Comparative Example 1), the glycolic acid copolyester prepared using titanium glycolate as a catalyst (Example 1) has better hydrolysis resistance in the esterification stage, still has high catalytic activity in the polycondensation stage, and the polymerization rate is stable and controllable. The prepared glycolic acid copolyester has a high molecular weight, and the polyester chips have an intrinsic viscosity of 0.65 dL / g, which is higher than 0.32 dL / g prepared using tetrabutyl titanate.
[0051] (2) Compared with adding a small amount of catalyst titanium glycolate in the esterification stage (Comparative Example 2), adding a sufficient amount of catalyst titanium glycolate (Example 2) can effectively increase the polycondensation reaction rate and avoid the problem of slow reaction rate caused by too little catalyst addition. The glycolate copolyester prepared in Example 2 has a higher molecular weight and a higher intrinsic viscosity polyester chip.
[0052] (3) Compared with the process conditions of different vacuum degrees (Comparative Example 3), the process conditions of vacuum degree lower than 100 Pa (Example 3) are necessary for preparing copolyester chips with high molecular weight and high intrinsic viscosity during polycondensation. Low vacuum degree is conducive to the devolatilization of small molecular substances, creating conditions for the polycondensation of macromolecular chain segments.
[0053] (4) Compared with the glycolic acid copolyester prepared using stannous octoate as a catalyst (Comparative Example 4), the glycolic acid copolyester prepared using titanium glycolate as a catalyst (Example 4) has better affinity for glycolic acid monomers, can improve the reactivity of glycolic acid in the reaction of three different monomers, and significantly improve the utilization rate of glycolic acid. The glycolic acid content in the copolyester is increased from 51.9% to 86.0%, which can reduce production costs. In addition, the degradation rate of the copolyester powder in the 180-day composting degradation rate test is 90.2%, and the prepared glycolic acid copolyester has a high glycolic acid content and good biodegradability. In addition, compared with heavy metal tin catalysts, titanium glycolate is a green titanium glycolate catalyst that can achieve green production of copolyesters. The obtained copolyester chips do not contain heavy metals and will not cause pollution to the environment during the treatment process, and have the characteristics of green environmental protection and eco-friendliness.
[0054] (5) The amount of glycolic acid monomer added during the preparation of glycolic acid copolyesters containing aromatic units also has a great influence on the degradability of glycolic acid copolyesters. Too high an amount of aromatic units added will make the prepared copolyester difficult to degrade. The glycolic acid copolyester prepared under the conditions of an input ratio of 0.5 mol of glycolic acid and 4.5 mol of bis(hydroxymethyl terephthalate) (Comparative Example 5) has a low glycolic acid content, and its powder has a degradation rate of only 15.6% in a 180-day composting degradation rate test. In comparison, the glycolic acid copolyester prepared under the conditions of an input ratio of 3.5 mol of glycolic acid and 1.5 mol of bis(hydroxymethyl terephthalate) (Example 5) has a glycolic acid content of 66.30%, and the degradation rate of the polyester powder in a 180-day composting degradation rate test is 72.8%.
[0055] (6) Comparing the process conditions of different esterification temperatures (Example 6 and Comparative Example 6), the esterification temperature of Comparative Example 6 was increased to 245°C, and the content of glycolic acid in the prepared polyester was significantly reduced, and the 180-day composting degradation rate also dropped to 63.8%. The content of glycolic acid in the copolyester chips (Example 6) prepared at an esterification temperature of 235°C was 76.4%, and the 180-day composting degradation rate was 83.5%. Although the high esterification temperature can increase the reaction rate to a certain extent, it will also lead to thermal degradation of glycolic acid, resulting in the loss of glycolic acid, thereby reducing the content of glycolic acid in the copolyester and causing the degradation performance of glycolic acid copolyester containing aromatic units to deteriorate.
[0056] (7) Compared with Example 4, the catalyst structure of Example 7 is The catalyst structure of Example 8 is a single In Examples 7 and 8, the acetic acid content in the glycolic acid copolyesters prepared (80.7% and 82.5%) was lower than 86.0% in Example 4, and the 180-day composting degradation rate of the copolyesters (87.4% and 90.6%) was also lower than 95.2% in Example 4. The reason is that the catalyst structure in Example 4 is a single It is a structure prepared by complete coordination of Ti and glycolic acid in a molar ratio of 1:2. The cyclic structure has good stability and better affinity for glycolic acid, which can promote the reaction of glycolic acid monomer with aromatic or fatty moieties. The structure of titanium glycolate is When the coordination is incomplete, the structure on the right is still the titanate structure before coordination; the structure of titanium glycolate is Because of the incomplete or over-coordination problem, the chain structure is unstable, so the catalytic effect in the reaction is not as good as that of a single structure.
[0057] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A method for preparing degradable glycolic acid copolyester using a titanium catalyst, characterized in that: The steps include: (1) putting a polyester raw material and a glycolic acid titanium catalyst into a reactor for esterification reaction to obtain an esterified product; the polyester raw material includes glycolic acid and a base; (2) subjecting the above esterified product to polycondensation with a stabilizer and an antioxidant to obtain a degradable glycolic acid copolyester.
2. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1, characterized in that: The titanium glycolate catalyst is a mixture of one or more of the following structures:
3. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1 or 2, characterized in that: The addition amount of the glycolate titanium catalyst is: the addition amount of the titanium element is 5-15 ppm of the theoretical total polyester mass.
4. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1, characterized in that: The unit is an aliphatic unit; the conditions for the esterification reaction are: reacting at 160-180° C. and 80-140 kPa nitrogen pressure for 2-5 hours; the conditions for the polycondensation reaction are: reacting at 190-230° C. and an absolute pressure lower than 100 Pa for 3-7 hours.
5. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 4, characterized in that: The aliphatic moiety is one or more of lactic acid, caprolactone, glycolide and lactide; the molar ratio of the aliphatic moiety to glycolic acid is 1:9-4:
1.
6. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1, characterized in that: The unit is an aromatic unit, and the polyester raw material also includes ethylene glycol; the conditions for the esterification reaction are: reacting at 210-235° C. and 100-200 kPa nitrogen pressure for 2-4 hours; the conditions for the polycondensation reaction are: reacting at 240-265° C. and an absolute pressure lower than 100 Pa for 3-6 hours.
7. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 6, characterized in that: The aromatic moiety is one or more of terephthalic acid, bis(hydroxymethyl) terephthalate, bis(hydroxyethyl) terephthalate, furandicarboxylic acid, bis(hydroxymethyl) furandicarboxylic acid, and bis(hydroxyethyl) furandicarboxylic acid; the molar ratio of the aromatic moiety to glycolic acid is 1:9-2:3; and the molar ratio of the aromatic moiety to ethylene glycol is 1:(1.1-1.3).
8. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1, characterized in that: The stabilizer is one or more of phosphoric acid, trimethyl phosphate, triethyl phosphate and triphenyl phosphate; the added amount of the stabilizer is 10-30ppm of the theoretical total polyester mass.
9. The method for preparing degradable glycolic acid copolyester using a titanium catalyst according to claim 1 or 8, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant THP-24, antioxidant 168, and antioxidant 1790; the added amount of the antioxidant is 50-300ppm of the theoretical total polyester mass.
10. The degradable glycolic acid copolyester prepared by the method for preparing degradable glycolic acid copolyester using a titanium-based catalyst according to any one of claims 1 to 9.