Biodegradable high-barrier-property PGA coated paper as well as preparation method and application thereof
By blending modified polyglycolic acid and polyurethane elastomer, and employing a two-step polycondensation method and hot press roller pressing technology, the problem of instability of PGA coated paper at high temperatures was solved, the thermal stability and mechanical properties of PGA coated paper were improved, its toughness and barrier properties were enhanced, and its service life was extended.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-30
- Publication Date
- 2026-04-10
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The PGA molecular chain itself has a narrow processing window temperature and is unstable at high temperatures, which leads to a shortened service life of the prepared PGA coated paper.
High-barrier PGA coated paper is prepared by blending modified polyglycolic acid and polyurethane elastomer, using a two-step polycondensation method, and end-capping with isocyanate methacrylate, combined with PLA coating and hot roll pressing.
The processing temperature window of PGA coated paper has been expanded, improving thermal stability and mechanical properties, enhancing toughness and barrier properties, and extending service life.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of coated paper technology, specifically to biodegradable high-barrier PGA coated paper, its preparation method, and its application. Background Technology
[0002] PGA-coated paper is a composite material that combines the properties of polyglycolic acid (PGA) with the coating process. As a biodegradable material, PGA has excellent biocompatibility, degrading into water and carbon dioxide within the human body without causing environmental pollution, thus meeting current environmental and sustainability requirements. Structurally, PGA has no side-chain methyl groups, its molecular chains are regular, and it possesses excellent crystallinity and a higher melting point. Testing shows that PGA crystals have a high modulus perpendicular to the molecular chain direction, and there are strong interactions between PGA molecular chains, resulting in better heat resistance and mechanical strength. This makes PGA-coated paper a promising candidate for applications in packaging, agriculture, and other fields.
[0003] However, PGA suffers from drawbacks such as a narrow processing window, high brittleness, and poor toughness, limiting its large-scale application. High molecular weight polyglycolic acid has fewer active end groups, resulting in effective toughening. Therefore, existing technologies often modify PGA through blending, melt copolymerization, and other methods. However, the PGA molecular chain itself has a narrow processing window and is unstable at high temperatures, easily undergoing cracking and reducing its relative molecular weight, thereby shortening the service life of the prepared PGA coated paper.
[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention
[0005] The purpose of this invention is to provide biodegradable high-barrier PGA coated paper, its preparation method and application, to solve the technical problem in the prior art that the PGA molecular chain itself has a narrow processing temperature window and is unstable at high temperatures, thus shortening the service life of the prepared PGA coated paper.
[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing biodegradable high-barrier PGA coated paper includes the following steps: S1, modified polyglycolic acid, polyurethane elastomer and initiator are added to a mixer and mixed to obtain a polymer; the polymer is cooled to obtain the prepared coating material. S2 and PLA are coated onto the coated paper substrate to form an adhesive layer; a coating layer material is then laminated onto the adhesive layer, and the paper is pressed together by a hot press roller to prepare a biodegradable high-barrier PGA coated paper.
[0007] Furthermore, the method for preparing the polyurethane elastomer includes the following steps: C1. Under a nitrogen atmosphere, itaconic acid is added to ethanol and stirred to dissolve, yielding an itaconic acid solution; lactic acid, the itaconic acid solution, and glycerol are mixed to form a reaction system; the reaction system is reacted at 60-80℃ for 2-3 hours to form a prepolymer system; C2 and isophorone diisocyanate were added dropwise to the above prepolymer system, and the reaction was continued at 55-65℃ for 3-6 hours to prepare a polyurethane elastomer solution. The polyurethane elastomer solution was then rotary evaporated at 80-85℃ until the ethanol was completely dried to obtain the prepared polyurethane elastomer.
[0008] Furthermore, the ratio of itaconic acid to ethanol is 10-20 mL: 100-120 mL; the ratio of lactic acid, itaconic acid solution, glycerol, and isophorone diisocyanate is 9-18 mL: 100-120 mL: 5-10 mL: 10-20 mL.
[0009] Furthermore, the preparation method of the modified polyglycolic acid includes the following steps: A1. Glycolic acid is added to a laboratory vacuum reactor and melt-polymerized at 150-160℃ and 60-70MPa for 2-3 hours to synthesize oligomeric glycolic acid. A2. Add tetrabutyl titanate, phenol and solvent to the above vacuum reactor, and continue polycondensation at 165-175℃ and 75-80MPa for 3-6 hours to obtain a mixture of polycondensates. A3. Under an inert gas atmosphere, isocyanate methacrylate is added to the condensation polymer mixture to form a closed reaction system. The reaction system is refluxed at 80-100℃ for 3-6 hours. Then, ethanol is removed by rotary evaporation, the solid is collected by filtration, the solid is washed with deionized water and dried to constant weight, which is the prepared modified polyglycolic acid.
[0010] Furthermore, the ratio of glycolic acid, tetrabutyl titanate, phenol, and solvent is 200-300 mL: 0.5-1 mL: 5-10 g: 20-30 mL.
[0011] Further, in step A3, the ratio of the condensation polymer mixture to isocyanate methacrylate is 100-120 mL: 1-5 mL.
[0012] Further, in step S1, the weight ratio of modified polyglycolic acid, polyurethane elastomer and initiator is 50-100:10-20:0.5-1, the mixing temperature is 210-220℃ and the mixing time is 3-5 min; in step S2, the coating thickness of the adhesive layer material is 1-2 mm; the pressing temperature is 80-90℃, the pressure is 0.8-1 MPa and the pressing time is 3-5 min.
[0013] As another aspect of the present invention, a method for preparing biodegradable high-barrier PGA coated paper provides a method for preparing biodegradable high-barrier PGA coated paper.
[0014] As another aspect of the present invention, the application of a biodegradable high-barrier PGA coated paper in the fields of fire-retardant packaging materials, biodegradable materials or flame-retardant materials.
[0015] The present invention has the following beneficial effects: 1. The modified polyglycolic acid prepared in this invention is divided into two steps: the first step is primary polymerization to form oligoglycolic acid; the second step is continued polycondensation to obtain a mixture of condensation polymers. In the primary polymerization stage, the oligoglycolic acid has a lower molecular weight, thus retaining a larger number of active end groups. In the polycondensation stage, a small amount of phenol is added to improve the benzene ring structure and rigidity of the synthesized polyglycolic acid. Furthermore, isocyanate methacrylate is used as a capping agent for end-group functionalization. On the one hand, the modified polyglycolic acid after end-capping treatment has stronger thermal stability and mechanical properties; on the other hand, unsaturated double bonds are introduced into the prepared modified polyglycolic acid. The above-mentioned modified polyglycolic acid can appropriately extend the processing temperature window, which is beneficial to the thermal stability of its melt blend with polyurethane elastomer.
[0016] 2. Lactic acid, itaconic acid, and glycerol undergo esterification to form a prepolymer system. Excess hydroxyl groups in the prepolymer system react with the isocyanate groups of isophorone diisocyanate to produce the prepared polyurethane elastomer. Polyurethane elastomers prepared from biodegradable lactic acid and glycerol have good biodegradability. Reacting excess hydroxyl functional groups with isophorone diisocyanate yields a polyurethane elastomer containing unsaturated bonds. The polyurethane elastomer prepared in this invention reacts with modified polyglycolic acid to improve the plastic deformation capacity of the prepared PGA coated paper, thereby improving its toughness. Furthermore, during the mixing process, the modified polyglycolic acid and polyurethane elastomer crosslink through unsaturated bonds, increasing the density and barrier properties of the coating layer material in the PGA coated paper. Detailed Implementation
[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1
[0018] This embodiment provides a method for preparing modified polyglycolic acid for biodegradable high-barrier PGA coated paper, including the following steps: A1. Select a 500mL laboratory vacuum reactor. The reactor has a discharge port at the bottom, and a nitrogen inlet, a temperature sensor, and a mechanical stirrer are connected sequentially to its side. Add 200mL of glycolic acid to the reactor. Set the reactor temperature to 150℃ and the pressure to 60MPa. Melt polycondensation is performed for 2 hours to synthesize oligomeric glycolic acid.
[0019] A2. Add 0.5 mL of tetrabutyl titanate, 5 g of phenol and 20 mL of ethanol to the vacuum reactor. Set the pressure of the vacuum reactor to 75 MPa and the temperature of the vacuum reactor to 165 °C. Continue polycondensation for 3 h to obtain a polycondensate mixture.
[0020] A3. A three-necked flask was filled with inert nitrogen gas. 100 mL of the condensation polymer mixture was added to the flask, followed by 1 mL of isocyanate methacrylate. The flask was then sealed to form the reaction system. The reaction was continued under reflux at 80 °C for 3 h. The ethanol was then removed by rotary evaporation, and the solid was collected by filtration. The solid was washed with deionized water and dried at 70 °C to constant weight, which yielded the prepared modified polyglycolic acid. Example 2
[0021] This embodiment provides a method for preparing modified polyglycolic acid for biodegradable high-barrier PGA coated paper, including the following steps: A1. A 500mL laboratory vacuum reactor was selected. The reactor has a discharge port at the bottom, and a nitrogen inlet, a temperature sensor, and a mechanical stirrer are connected sequentially to its side. 255mL of glycolic acid was added to the reactor. The reactor temperature was set to 155℃, and the pressure to 65MPa. Melt polycondensation was carried out for 2.5 hours to synthesize oligomeric glycolic acid.
[0022] A2. Add 0.6 mL of tetrabutyl titanate, 6 g of phenol and 25 mL of ethanol to the vacuum reactor. Set the pressure of the vacuum reactor to 78 MPa and the temperature of the vacuum reactor to 170 °C. Continue polycondensation for 3 h to obtain a polycondensate mixture.
[0023] A3. A three-necked flask was filled with inert nitrogen gas. 110 mL of the condensation mixture was added to the three-necked flask, followed by 3 mL of isocyanate methacrylate. The mixture was reacted at 90 °C for 5 h. The ethanol was then removed by rotary evaporation, and the solid was collected by filtration. The solid was washed with deionized water and dried at 75 °C to constant weight, which is the prepared modified polyglycolic acid. Example 3
[0024] This embodiment provides a method for preparing modified polyglycolic acid for biodegradable high-barrier PGA coated paper, including the following steps: A1. Select a 500mL laboratory vacuum reactor. The reactor has a discharge port at the bottom, and a nitrogen inlet, a temperature sensor, and a mechanical stirrer are connected sequentially to its side. Add 300mL of glycolic acid to the reactor. Set the reactor temperature to 160℃ and the pressure to 70MPa. Melt polycondensation is carried out for 3 hours to synthesize oligomeric glycolic acid.
[0025] A2. Add 1 mL of tetrabutyl titanate, 10 g of phenol and 30 mL of ethanol to the vacuum reactor. Set the pressure of the vacuum reactor to 80 MPa and the temperature of the vacuum reactor to 175 °C. Continue polycondensation for 4 h to obtain a polycondensate mixture.
[0026] A3. A three-necked flask is filled with inert nitrogen gas. 120 mL of the condensation mixture is added to the three-necked flask. 5 mL of isocyanate methacrylate is then added to the three-necked flask. The reaction is continued at 100 °C for 6 h. The ethanol is then removed by rotary evaporation, and the solid is collected by filtration. The solid is washed with deionized water and dried at 80 °C to constant weight, which is the prepared modified polyglycolic acid. Example 4
[0027] This embodiment provides a method for preparing a biodegradable, high-barrier PGA coated paper polyurethane elastomer, including the following steps: C1. Add 9 mL of lactic acid to a 250 mL three-necked flask and evacuate the flask to place it under a nitrogen atmosphere. Add 10 mL of itaconic acid to 100 mL of ethanol and stir to dissolve, obtaining an itaconic acid solution. Add 100 mL of the itaconic acid solution and 5 mL of glycerol to the three-necked flask using a syringe to form a reaction system. Transfer the three-necked flask to a water bath and react the system at 60 °C for 2 hours to form a prepolymer system.
[0028] C2. Add 10 mL of isophorone diisocyanate dropwise to the above prepolymer system at a rate of 1 mL / min, and continue the reaction at 55 °C for 3 h to prepare a polyurethane elastomer solution. Pour the polyurethane elastomer liquid into a glass petri dish and rotary evaporate at 80 °C until the solvent is completely dried to obtain the prepared polyurethane elastomer. Example 5
[0029] This embodiment provides a method for preparing a biodegradable, high-barrier PGA coated paper polyurethane elastomer, including the following steps: C1. Add 12 mL of lactic acid to a 250 mL three-necked flask and evacuate the flask to place it under a nitrogen atmosphere. Add 15 mL of itaconic acid to 110 mL of ethanol and stir to dissolve, obtaining an itaconic acid solution. Add 110 mL of the itaconic acid solution and 8 mL of glycerol to the three-necked flask using a syringe to form a reaction system. Transfer the three-necked flask to a water bath and react the system at 70 °C for 2.5 h to form a prepolymer system.
[0030] C2. 15 mL of isophorone diisocyanate was added dropwise to the above prepolymer system at a rate of 1.5 mL / min, and the reaction was continued at 60 °C for 5 h to prepare a polyurethane elastomer solution. The polyurethane elastomer liquid was poured into a glass petri dish and rotary evaporated at 82 °C until the solvent was completely dried to obtain the prepared polyurethane elastomer. Example 6
[0031] This embodiment provides a method for preparing a biodegradable, high-barrier PGA coated paper polyurethane elastomer, including the following steps: C1. Add 18 mL of lactic acid to a 250 mL three-necked flask and evacuate the flask to a nitrogen atmosphere. Add 20 mL of itaconic acid to 120 mL of ethanol and stir to dissolve, obtaining an itaconic acid solution. Add 120 mL of the itaconic acid solution and 10 mL of glycerol to the three-necked flask using a syringe to form a reaction system. Transfer the three-necked flask to a water bath and react the system at 80 °C for 3 hours to form a prepolymer system.
[0032] C2, 20 mL of isophorone diisocyanate was added dropwise to the above prepolymer system at a rate of 2 mL / min, and the reaction was continued at 65 °C for 6 h to prepare a polyurethane elastomer solution. The polyurethane elastomer liquid was poured into a glass petri dish and rotary evaporated at 85 °C until the solvent was completely dried to obtain the prepared polyurethane elastomer. Example 7
[0033] This embodiment provides a method for preparing biodegradable high-barrier PGA coated paper, including the following steps: S1. By weight, 50 parts of the modified polyglycolic acid prepared in Example 1, 10 parts of the polyurethane elastomer prepared in Example 4, and 0.5 parts of benzoyl peroxide were added to a mixer and mixed. The temperature of the mixer was set to 210°C and the mixing time was 3 minutes to obtain the polymer. The polymer was allowed to cool naturally to room temperature, which is the prepared coating material.
[0034] S2. Using coated paper as the substrate, PLA is applied to the substrate surface as an adhesive layer material with a coating thickness of 1 mm to form an adhesive layer; a coating layer material is then applied to the adhesive layer and pressed by a hot press roller at a temperature of 80°C, a pressure of 0.8 MPa, and a pressing time of 3 min to prepare a biodegradable high-barrier PGA coated paper. Example 8
[0035] This embodiment provides a method for preparing biodegradable high-barrier PGA coated paper, including the following steps: S1. By weight, 80 parts of the modified polyglycolic acid prepared in Example 2, 15 parts of the polyurethane elastomer prepared in Example 5, and 0.8 parts of benzoyl peroxide were added to a mixer and mixed. The temperature of the mixer was set to 215°C and the mixing time was 5 minutes to obtain the polymer. The polymer was allowed to cool naturally to room temperature, which is the prepared coated paper material.
[0036] S2. Using coated paper as the substrate, PLA is applied to the substrate surface as the adhesive layer material with a coating thickness of 1.5 mm to form an adhesive layer; a coating layer material is then applied to the adhesive layer and pressed by a hot press roller at a temperature of 85℃, a pressure of 0.9 MPa, and a pressing time of 4 min to prepare a biodegradable high-barrier PGA coated paper. Example 9
[0037] This embodiment provides a method for preparing biodegradable high-barrier PGA coated paper, including the following steps: S1. By weight, 100 parts of the modified polyglycolic acid prepared in Example 3, 20 parts of the polyurethane elastomer prepared in Example 6, and 1 part of benzoyl peroxide were added to a mixer and mixed. The temperature of the mixer was set to 220°C and the mixing time was 5 minutes to obtain the polymer. The polymer was allowed to cool naturally to room temperature, which is the prepared coating material.
[0038] S2. Using coated paper as the substrate, PLA is applied to the surface of the substrate as an adhesive layer material with a coating thickness of 1-2 mm to form an adhesive layer; a coating layer material is then applied to the adhesive layer and pressed by a hot press roller at a temperature of 90℃, a pressure of 1MPa, and a pressing time of 5 minutes to prepare a biodegradable high-barrier PGA coated paper.
[0039] Comparative Example 1 The difference between this comparative example and Example 9 is that phenol was not added in step A2 when preparing the modified polyglycolic acid.
[0040] Comparative Example 2 The difference between this comparative example and Example 9 is that ethyl isocyanate methacrylate was not added in step A3 when preparing the modified polyglycolic acid.
[0041] Comparative Example 3 The difference between this comparative example and Example 9 is that the steps for preparing the polyurethane elastomer are as follows: C1. Add 18 mL of lactic acid to a 250 mL three-necked flask and evacuate the flask to a nitrogen atmosphere. Add 20 mL of itaconic acid to 120 mL of ethanol and stir to dissolve, obtaining an itaconic acid solution. Add 120 mL of the itaconic acid solution and 10 mL of glycerol to the three-necked flask using a syringe to form a reaction system. Transfer the three-necked flask to a water bath and react the system at 80 °C for 3 hours to form a prepolymer system.
[0042] C2. Pour the prepolymer system into a glass petri dish and rotary evaporate at 85°C until the solvent is completely dried to obtain the prepared polyurethane elastomer.
[0043] Performance testing: 1. The biodegradable high-barrier PGA coated papers prepared in Examples 7-9 and Comparative Examples 1-3 were made into dumbbell-shaped samples; the tensile strength and elongation at break of the samples were tested according to GB / T528-2009. The tensile rate of the instrument was set to 20 mm / min, and the test temperature was 25℃.
[0044] 2. The biodegradable high-barrier PGA coated paper prepared in Examples 7-9 and Comparative Examples 1-3 was cut into samples with a length of 80 mm, a width of 10 mm, a notch depth of 2 mm, and a thickness of 4 mm. The notched impact strength of the samples was determined using a cantilever beam combined impact testing machine according to GB / T1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams".
[0045] Table 1. Sample performance test data
[0046] Data Analysis: As shown in Table 1, the biodegradable high-barrier PGA films prepared in Examples 7-9 of this invention possess excellent mechanical properties, exhibiting high tensile strength, elongation at break, and notched impact strength. In Comparative Example 1, phenol was not added during the preparation of modified polyglycolic acid, resulting in the absence of a benzene ring structure and a decrease in mechanical properties.
[0047] 3. Take 10 mg of the biodegradable high-barrier PGA coated paper prepared in Examples 7-9 and Comparative Examples 1-3, and use a thermal analyzer to determine the glass transition temperature and melting point of the high-barrier PGA coated paper.
[0048] 4. Take 10 mg of the biodegradable high-barrier PGA coated paper prepared in Examples 7-9 and Comparative Examples 1-3 respectively, and soak it in a test tube containing phosphate buffer solution at pH 7.4. Then place the test tube in a constant temperature water bath at 37°C. After 5 days, take out the sample, wash the surface with deionized water, and vacuum dry it at 50°C to constant weight. The degree of degradation is calculated using the following formula: Degradation rate (%) = (D0 - D / D0) × 100% Where D0 is the weight of the biodegradable high-barrier PGA coated paper before degradation; D is the weight of the biodegradable high-barrier PGA coated paper after 5 days of degradation; three groups of samples were measured in parallel, and their average value was taken.
[0049] Table 2. Sample performance test data
[0050] Data Analysis: The biodegradable high-barrier PGA coating materials prepared in Examples 7-9 of this invention exhibit excellent thermal stability, as evidenced by their high glass transition temperature and melting point. However, in Comparative Example 2, the modified polyglycolic acid was not end-capped with isocyanate methacrylate; in Comparative Example 3, isophorone diisocyanate was not end-capped when preparing the polyurethane elastomer. The thermal stability of the biodegradable high-barrier PGA coating paper prepared in Comparative Examples 2 and 3 decreased, as evidenced by a decrease in both the glass transition temperature and melting point. The polyurethane elastomers prepared in Examples 7-9 and Comparative Examples 1-3, as crosslinkers of polyglycolic acid and polyurethane elastomers, all possess good environmental performance, exhibiting high degradability.
[0051] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.
[0052] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0053] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. Process for the preparation of biodegradable high-barrier PGA-coated paper, characterized in that, It comprises the following steps: S1, the modified polyglycolic acid, polyurethane elastomer and initiator are added into the internal mixer to be mixed, and a polymer is obtained; the polymer is cooled, and the prepared laminated film material is obtained; S2, the PLA is coated on the copper plate paper substrate to form a bonding layer; the bonding layer is overlaid with the laminated film material, and is pressed by a hot press roller to prepare the biodegradable high-barrier PGA laminated paper.
2. The process for the preparation of biodegradable high barrier PGA-coated paper according to claim 1, characterized in that, The preparation method of the polyurethane elastomer comprises the following steps: C1, under the nitrogen atmosphere, itaconic acid is added into ethanol to be stirred and dissolved to obtain an itaconic acid solution; lactic acid, the itaconic acid solution and glycerol are blended to form a reaction system; the reaction system is reacted at 60-80 DEG C for 2-3 h to form a prepolymer system; C2, isophorone diisocyanate is added dropwise into the above prepolymer system, and the reaction is continued at 55-65 DEG C for 3-6 h to prepare a polyurethane elastomer solution; the polyurethane elastomer solution is rotary evaporated at 80-85 DEG C until the ethanol is completely dried, and the prepared polyurethane elastomer is obtained.
3. The method for preparing biodegradable high-barrier PGA coated paper according to claim 2, characterized in that, The amount ratio of itaconic acid to ethanol is 10-20 mL:100-120 mL; the amount ratio of lactic acid, itaconic acid solution, glycerol and isophorone diisocyanate is 9-18 mL:100-120 mL:5-10 mL:10-20 mL.
4. The method of claim 1, wherein the biodegradable high-barrier PGA-coated paper is characterized by, The preparation method of the modified polyglycolic acid comprises the following steps: A1, a laboratory vacuum reactor is added with glycolic acid, and is subjected to melt polycondensation at 150-160 DEG C and 60-70 MPa for 2-3 h to synthesize oligomeric glycolic acid; A2, tetrabutyl titanate, phenol and a solvent are added into the above vacuum reactor, and are subjected to polycondensation at 165-175 DEG C and 75-80 MPa for 3-6 h to obtain a polycondensate mixture; A3, under the inert gas atmosphere, isocyanatoethyl methacrylate is added into the polycondensate mixture to form a reaction system; the reaction system is closed and is subjected to reflux reaction at 80-100 DEG C for 3-6 h, and then the ethanol is removed by rotary evaporation, the solid is collected by filtration, the solid is washed with deionized water, and is dried to constant weight, and the prepared modified polyglycolic acid is obtained.
5. The process for the preparation of biodegradable high barrier PGA-coated paper according to claim 4, characterized in that, The amount ratio of glycolic acid, tetrabutyl titanate, phenol and the solvent is 200-300 mL:0.5-1 mL:5-10 g:20-30 mL.
6. The method for preparing biodegradable high-barrier PGA coated paper according to claim 4, characterized in that, In step A3, the amount ratio of the polycondensate mixture to isocyanatoethyl methacrylate is 100-120 mL:1-5 mL.
7. The method for preparing biodegradable high-barrier PGA coated paper according to claim 1, characterized in that, In step S1, the weight ratio of the modified polyglycolic acid, the polyurethane elastomer and the initiator is 50-100:10-20:0.5-1, the mixing temperature is 210-220 DEG C, and the mixing time is 3-5 min; in step S2, the coating thickness of the bonding layer material is 1-2 mm; the pressing temperature is 80-90 DEG C, the pressing pressure is 0.8-1 MPa, and the pressing time is 3-5 min.
8. A biodegradable, high-barrier PGA-coated paper, characterized by, The biodegradable high-barrier PGA laminated paper is prepared by the preparation method of the biodegradable high-barrier PGA laminated paper according to any one of claims 1-7.
9. Use of a biodegradable, high-barrier PGA-coated paper according to claim 8, characterized in that, It is applied to the field of fireproof packaging materials, degradable materials or flame-retardant materials.