Environmentally friendly slurry and preparation method thereof

Abstract

The invention discloses a kind of preparation method of environment-friendly slurry, including:Polylactic acid-glycolic acid copolymer is dissolved in cosolvent and stirred to completely dissolve to obtain mixed solution, then rare earth metal compound is added while stirring in solution, after adding, cooling is carried out and insulation is carried out, finally cooled to room temperature, filtered, and modified polylactic acid-glycolic acid copolymer solution is obtained;Epoxy resin is ultrasonically dispersed in the mixed solution of organic solvent / citrate buffer, then organic silane is added and stirred to react, after the question reaction terminates, slowly drip saturated sodium bicarbonate solution to solution pH value to 7 7.5 in product solution, then the above-mentioned modified polylactic acid-glycolic acid copolymer solution and diamino compound obtained are added sequentially, and after solution reaction, cooling and standing under natural conditions is filtered, and the obtained solution is environment-friendly slurry. The slurry made according to the present invention is easily degraded, has low viscosity, and has excellent film-forming properties, and ultimately realizes green warp sizing.

Description

Technical Field

[0001] The invention belongs to the technical field of textiles, and particularly relates to an environmentally friendly slurry and a preparation method thereof. Background Art

[0002] Warp sizing is a crucial step in textile production. Its role can be summarized as follows: sizing enhances the strength and abrasion resistance of synthetic staple fibers and fine, densely woven yarns, while also maintaining their stretch by removing hairiness. Warp sizing not only reduces yarn breakage rates during weaving and ensures the yarns can withstand the repetitive forces of the loom, but also significantly improves fabric quality and production efficiency.

[0003] The sizing agent is extremely important in the sizing process. With the continuous evolution and development of sizing, the main sizing agents currently include starch sizing, polyvinyl alcohol (PVA) sizing, and polyacrylic acid sizing. As a polymer compound, sizing is an essential component in the fabric sizing process. Starch sizing (including modified starch sizing) has become the main sizing agent in the entire sizing agent market due to its excellent affinity for cotton fibers and easy degradability. However, the sizing film formed by starch sizing is brittle and hard, making it difficult to sizing alone. It is generally compounded with polyvinyl alcohol sizing. However, due to the environmental impact of polyvinyl alcohol sizing, its use is restricted. Polyvinyl alcohol (PVA) molecules contain a large number of hydrophilic groups—hydroxyl groups—making it a typical water-soluble polymer. PVA easily forms a colorless, transparent film. The film formed by PVA not only has excellent mechanical properties, but also has a smooth surface that is not prone to adhesion. Furthermore, PVA's excellent miscibility allows it to be widely used in yarn sizing and can be mixed with other sizing agents. The resulting sizing solution is relatively stable and less prone to delamination. PVA sizing is widely used in the textile industry not only because of its excellent water solubility, film-forming properties, adhesion, and emulsification, but also because of its excellent oil and solvent resistance. However, its serious environmental pollution and high wastewater treatment costs and difficulties limit its use. Acrylic sizing is a general term for homopolymers, copolymers, or blends of acrylic monomers. Acrylic sizing not only has excellent permeability and strong adhesion to hydrophobic fibers, but also easily forms films. The resulting films are flexible, easily desized, and relatively easy to degrade. However, most commercially available acrylic sizing agents are composed of copolymers or blends of monomers, and their diverse production methods lead to diverse and complex performance characteristics.

[0004] Environmentally friendly sizing refers to sizing that produces wastewater during the printing and dyeing desizing process that causes little or no pollution to the ecological environment. Furthermore, the production and use of the sizing, as well as the resulting final product, are beneficial to human health and do not endanger human life and health. During the production and use of sizing, environmentally friendly raw materials should be used whenever possible to conserve water, reduce the extraction of natural resources, maximize the use of renewable resources, and minimize pollution to the ecological environment. In short, the basic requirements for green and environmentally friendly sizing are: maximizing the use of recyclable and biodegradable raw materials, and having no adverse effects on the environment or human health during production and use. With the continuous development of technology, environmentally friendly sizing is becoming an increasingly sought-after goal in current sizing.

[0005] Currently, starch sizing (including modified starch sizing) accounts for the majority of the sizing market, with starch-based sizing accounting for 74% of the total sizing market. However, the other two types of sizing applications each account for approximately 10%. In addition to these three main sizing materials, other independently developed sizing materials account for approximately 3%. However, since each of the three main sizing materials has its own advantages and disadvantages, actively developing independently developed sizing materials remains the primary research goal.

[0006] Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable functional polymer organic compound formed by the random polymerization of two monomers, lactic acid and glycolic acid. It exhibits excellent biocompatibility, is non-toxic, and exhibits excellent encapsulation and film-forming properties. It is widely used in pharmaceuticals, medical engineering materials, and modern industry. However, a search revealed that PLGA is currently rarely used in the preparation of textile slurries. The present invention utilizes the fundamental properties of PLGA and employs a suitable method to prepare an environmentally friendly slurry. Summary of the Invention

[0007] In response to the above problems, the present invention aims to provide an environmentally friendly sizing agent and a method for preparing the same. The sizing agent prepared according to the present invention exhibits excellent properties, such as easy degradation, low viscosity, and good film-forming properties. It can replace traditional sizing agents in the sizing process of high-ratio polyester-cotton blended yarns, ultimately achieving environmentally friendly warp sizing.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] One aspect of the present invention provides a method for preparing an environmentally friendly slurry, the method comprising the following steps:

[0010] A polylactic acid-co-glycolic acid copolymer is dissolved in a co-solvent at a mass-to-volume ratio of 1 g:10-30 mL and stirred until completely dissolved to obtain a mixed solution, then the mixed solution is heated to 80-100° C. and the temperature is maintained constant, and a rare earth metal compound is added to the solution while stirring. After the addition is complete, the temperature is lowered to 40-60° C. and kept warm for 2-5 hours. After the insulation is completed, the solution is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified polylactic acid-co-glycolic acid copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:1-5 g;

[0011] Ultrasonic dispersion of epoxy resin in a mixture of an organic solvent / citrate buffer solution, followed by addition of organosilane and stirring the mixture at 100-120° C. for 1-3 hours. After the reaction is completed, a saturated sodium bicarbonate solution is slowly added dropwise to the product solution until the pH of the solution reaches 7-7.5. The modified polylactic acid-glycolic acid copolymer solution and the diamino compound obtained above are then added in sequence. The solution is stirred at 35-45° C. for 8-12 hours, cooled naturally, allowed to stand for 12-18 hours, and then filtered. The resulting solution is an environmentally friendly slurry.

[0012] During the above reaction process, the epoxy resin and the organosilane are added in a volume ratio of 1-3 mL: 0.1-0.5 mL; the product solution, the modified polylactic acid-glycolic acid copolymer solution and the diamino compound are added in a volume mass ratio of 1 mL: 5-10 mL: 0.04-0.08 g.

[0013] Furthermore, the polylactic acid-glycolic acid copolymer consists of 60-80% of lactic acid and 20-40% of glycolic acid.

[0014] Furthermore, the co-solvent is any one of chloroform, dichloromethane, tetrahydrofuran, acetone, and ethyl acetate.

[0015] Furthermore, the rare earth metal compound is selected from the chloride, hydroxide, nitrate, carbonate or sulfate of any one or more rare earth metals.

[0016] Furthermore, the rare earth metal is selected from any one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0017] Furthermore, the epoxy resin is selected from any one of bisphenol S epoxy resin, bisphenol F epoxy resin, bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, and novolac epoxy resin, or a mixture of two or more thereof; the molecular weight of the epoxy resin is 4000-8000.

[0018] Furthermore, the organic solvent / citrate buffer mixture is formed by mixing 30-50% by volume of the organic solvent and 50-70% by volume of the citrate buffer.

[0019] Furthermore, the organic solvent is selected from one or a mixture of two or more of N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0020] Furthermore, the organosilane is one or a mixture of two or more of methyltrimethoxysilane, tetramethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, ethyltriethoxysilane and tetrapropoxysilane.

[0021] Furthermore, the diamino compound is one or more selected from 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene, and o-tolidine.

[0022] Compared with the prior art, the present invention achieves the following beneficial effects: based on the good biocompatibility, non-toxicity, and excellent encapsulation and film-forming properties of polylactic acid-glycolic acid copolymer, the present invention uses the copolymer as the main raw material to prepare textile slurry. The present invention first prepares the polylactic acid-glycolic acid copolymer into a solution and then reacts it with a rare earth metal compound. The rare earth metal compound modifies the polylactic acid-glycolic acid copolymer, increases the surface charge of the polylactic acid-glycolic acid copolymer, and thus increases the reactivity of the polymer. Secondly, the epoxy resin is dispersed in a mixed solution consisting of an organic solvent and a citrate buffer solution, the epoxy resin is ring-opened by the carboxyl group in the mixed solution, and then reacted with an organosilane, utilizing the structural remodeling effect of the organosilane on the epoxy resin, to form a super surface active and small size effect and macroscopic quantum tunneling effect between the molecules, thereby improving the molecular force between the modified polylactic acid-glycolic acid copolymer solution, and adjusting the solution pH to neutral or weakly alkaline after the reaction, and then adding the modified polylactic acid-glycolic acid copolymer solution and the diamino compound for stirring and reacting to obtain the final product slurry. These several reactants provide abundant carboxyl groups and amino groups for the entire reaction system, so that the prepared slurry has excellent film-forming properties and improves the hydrophilicity of the slurry. The slurry obtained according to the method of the present invention has the characteristics of good fluidity, strong bonding force, not easy to form a skin, good film-forming property, etc. The slurry of the present invention is easily degraded, will not cause pollution to the environment during the desizing process, and ultimately achieves green and environmentally friendly sizing. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1:

[0025] A poly(lactic acid-co-glycolic acid) copolymer (composed of 70% lactic acid and 30% glycolic acid) is dissolved in tetrahydrofuran at a mass-to-volume ratio of 1 g:20 mL, and stirred until completely dissolved to obtain a mixed solution; the mixed solution is then heated to 90° C. and maintained at this temperature; a rare earth metal compound (a mixture of lanthanum chloride and cerium hydroxide in a mass ratio of 1:1, the same below) is added to the solution while stirring; after the addition is complete, the temperature is lowered to 50° C. and maintained for 3.5 hours; after the maintenance is completed, the solution is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified poly(lactic acid-co-glycolic acid) copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:3 g;

[0026] The epoxy resin (bisphenol S type epoxy resin, molecular weight of 4000-8000) was ultrasonically dispersed in a mixture of organic solvent / citrate buffer (mixed by 40% volume fraction of N,N-dimethylformamide and 60% volume fraction of citrate buffer) in a volume ratio of 2mL:0.3mL, and then methyltrimethoxysilane was added and stirred at 110°C for 2h. After the reaction, a saturated sodium bicarbonate solution was slowly added dropwise to the product solution until the pH of the solution was 7-7.5. Then, the modified polylactic acid-glycolic acid copolymer solution and p-phenylenediamine obtained above were added in a volume mass ratio of 1mL:7.5mL:0.06g of the product solution, the modified polylactic acid-glycolic acid copolymer solution and p-phenylenediamine, and the solution was stirred at 40°C for 10h, cooled and allowed to stand for 15h under natural conditions, and then filtered. The resulting solution was an environmentally friendly slurry.

[0027] Example 2:

[0028] A poly(lactic acid-co-glycolic acid) copolymer (composed of 60% lactic acid and 40% glycolic acid) is dissolved in tetrahydrofuran at a mass-to-volume ratio of 1 g:30 mL and stirred until completely dissolved to obtain a mixed solution; the mixed solution is then heated to 100° C. and a rare earth metal compound (a mixture of lanthanum chloride and neodymium chloride in a mass ratio of 1:2, the same below) is added to the solution while stirring after the addition is completed; the mixture is cooled to 60° C. and kept warm for 2 hours; after the insulation is completed, the mixture is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified poly(lactic acid-co-glycolic acid) copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:5 g;

[0029] The epoxy resin (bisphenol F epoxy resin, molecular weight 4000-8000) was ultrasonically dispersed in a mixture of organic solvent / citrate buffer (composed of 30% volume fraction of N-methylpyrrolidone and 70% volume fraction of citrate buffer) in a volume ratio of 3 mL:0.5 mL, and then tetramethoxysilane was added and stirred at 100 ° C for 3 hours. After the reaction, a saturated sodium bicarbonate solution was slowly added dropwise to the product solution until the pH of the solution was 7-7.5. Then, the modified polylactic acid-glycolic acid copolymer solution and 3,4'-diaminodiphenyl ether obtained above were added in a volume mass ratio of 1 mL:5 mL:0.04 g to the product solution, the modified polylactic acid-glycolic acid copolymer solution and 3,4'-diaminodiphenyl ether, and the solution was stirred at 45 ° C for 8 hours, cooled and allowed to stand for 12 hours under natural conditions, and then filtered. The resulting solution was an environmentally friendly slurry.

[0030] Example 3:

[0031] A poly(lactic acid-co-glycolic acid) copolymer (composed of 80% lactic acid and 20% glycolic acid) is dissolved in tetrahydrofuran at a mass-to-volume ratio of 1 g:10 mL and stirred until completely dissolved to obtain a mixed solution, and then the mixed solution is heated to 80° C. and maintained at the same temperature, and a rare earth metal compound (a mixture of neodymium chloride, lutetium hydroxide, and neodymium hydroxide in a mass ratio of 1:1:1, the same below) is added to the solution while stirring; after the addition is complete, the temperature is lowered to 40° C. and kept warm for 5 hours. After the insulation is completed, the mixture is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified poly(lactic acid-co-glycolic acid) copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:1 g;

[0032] The epoxy resin (bisphenol A epoxy resin, molecular weight of 4000-8000) was ultrasonically dispersed in a mixture of organic solvent / citrate buffer (mixed by 50% volume fraction of dimethyl sulfoxide and 50% volume fraction of citrate buffer) in a volume ratio of 1 mL:0.1 mL, and then methyltriethoxysilane was added and stirred at 120°C for 1 hour. After the reaction, a saturated sodium bicarbonate solution was slowly added dropwise to the product solution until the pH of the solution was 7-7.5. Then, the modified polylactic acid-glycolic acid copolymer solution and 4,4'-diaminodiphenyl ether obtained above were added in a volume mass ratio of 1 mL:10 mL:0.08 g to the product solution, the modified polylactic acid-glycolic acid copolymer solution and 4,4'-diaminodiphenyl ether, and the solution was stirred at 35°C for 12 hours, cooled and allowed to stand for 18 hours under natural conditions, and then filtered. The resulting solution was an environmentally friendly slurry.

[0033] Comparative Example 1:

[0034] Poly(lactic acid-co-glycolic acid) (composed of 70% lactic acid and 30% glycolic acid) was dissolved in tetrahydrofuran at a mass volume ratio of 1 g:20 mL and stirred until completely dissolved to obtain a poly(lactic acid-co-glycolic acid) solution;

[0035] Epoxy resin (bisphenol S type epoxy resin, molecular weight 4000-8000) was ultrasonically dispersed in a mixture of organic solvent / citrate buffer (mixed by 40% volume fraction of N,N-dimethylformamide and 60% volume fraction of citrate buffer) in a volume ratio of 2mL:0.3mL, and then methyltrimethoxysilane was added and stirred at 110°C for 2h. After the reaction, a saturated sodium bicarbonate solution was slowly added dropwise to the product solution until the pH of the solution was 7-7.5. Then, the polylactic acid-glycolic acid copolymer solution and p-phenylenediamine obtained above were added in a volume mass ratio of 1mL:7.5mL:0.06g to the product solution, the polylactic acid-glycolic acid copolymer solution, and p-phenylenediamine. The solution was stirred for reaction at 40°C for 10h, cooled and allowed to stand for 15h under natural conditions, and then filtered to obtain a slurry.

[0036] Comparative Example 2:

[0037] Poly(lactic acid-co-glycolic acid) (composed of 70% lactic acid and 30% glycolic acid) was dissolved in tetrahydrofuran at a mass volume ratio of 1 g:20 mL and stirred until completely dissolved to obtain a poly(lactic acid-co-glycolic acid) solution;

[0038] An epoxy resin (bisphenol S epoxy resin, molecular weight 4000-8000) was ultrasonically dispersed in a mixture of an organic solvent / citrate buffer (composed of a mixture of 40% by volume of N,N-dimethylformamide and 60% by volume of citrate buffer) in a volume ratio of 2 mL:0.3 mL to obtain an epoxy resin solution. The polylactic acid-glycolic acid copolymer solution and p-phenylenediamine obtained above were then added in a volume mass ratio of 1 mL:7.5 mL:0.06 g of the epoxy resin solution, the polylactic acid-glycolic acid copolymer solution, and p-phenylenediamine. The solution was stirred and reacted at 40° C. for 10 hours, then cooled and allowed to stand under natural conditions for 15 hours, and then filtered. The resulting solution was the slurry.

[0039] Comparative Example 3:

[0040] A poly(lactic acid-co-glycolic acid) copolymer (composed of 70% lactic acid and 30% glycolic acid) is dissolved in tetrahydrofuran at a mass-to-volume ratio of 1 g:20 mL, and stirred until completely dissolved to obtain a mixed solution; the mixed solution is then heated to 90° C. and maintained at this temperature; a rare earth metal compound (a mixture of lanthanum chloride and cerium hydroxide in a mass ratio of 1:1, the same below) is added to the solution while stirring; after the addition is complete, the temperature is lowered to 50° C. and maintained for 3.5 hours; after the maintenance is completed, the solution is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified poly(lactic acid-co-glycolic acid) copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:3 g;

[0041] The modified polylactic acid-glycolic acid copolymer solution obtained above and p-phenylenediamine were mixed in a volume mass ratio of 7.5 mL:0.06 g, stirred and reacted at 40° C. for 10 h, cooled and allowed to stand for 15 h under natural conditions, and then filtered to obtain a slurry.

[0042] Test Example 1: Performance testing of different slurries

[0043] Experimental objects: Examples 1-3 and Comparative Examples 1-3

[0044] Experimental methods:

[0045] 1. Slurry viscosity test: The slurry of each example was prepared into a slurry with a volume fraction of 6%, and the viscosity was measured using an NDJ-5S digital rotational viscometer. The test conditions were a temperature of 25°C ± 0.5°C, using rotor 1, and setting the speed to 60 rpm;

[0046] 2. The slurry adhesion test adopts the roving method, and the specific process is as follows:

[0047] (1) The slurry of each example was prepared into 1000 ml of slurry with a volume fraction of 1%, poured into a constant temperature stirrer at 95°C and stirred for 1 hour until uniform, and sealed with plastic wrap to prevent evaporation of water.

[0048] (2) Select pure cotton combed 14.5tex yarn as required, and wind 20 roving strips on an aluminum alloy frame for later use.

[0049] (3) Place the prepared sample and aluminum alloy frame into the slurry. After immersion for 5 minutes, lift the aluminum alloy frame and let it dry naturally. Cut the dried sample and place it under constant temperature and humidity conditions of 20°C and 65% relative humidity for 24 hours.

[0050] (4) The dried roving was tested for breaking strength using a Lai YG065 electronic textile strength tester. The test conditions were: clamping distance 100 mm; tensile speed 50 mm / min.

[0051] Experimental results: as shown in Table 1.

[0052] Table 1 Viscosity and adhesion test of different slurries

[0053] Project Number Viscosity (mPa·s) Adhesion force (N) Example 1 4.76 80.6 Example 2 4.84 76.9 Example 3 4.87 77.2 Comparative Example 1 3.92 63.6 Comparative Example 2 3.36 56.6 Comparative Example 3 3.31 58.7

[0054] It can be seen from the results in Table 1 that, compared with Comparative Examples 1-3, the viscosity of the slurries of Examples 1-3 of the present invention is not much different, but the adhesion is significantly higher, which shows that the slurries of the present invention have excellent adhesion.

[0055] Test Example 2: Sizing Performance Test

[0056] Experimental objects: Examples 1-3 and Comparative Examples 1-3

[0057] Test method: Based on GB / T3916-2013. The raw yarn was a 90 / 10 polyester / cotton blend. The breaking strength and elongation of the raw yarn were 374.5 cN and 6.19%, respectively.

[0058] Experimental results: as shown in Table 2.

[0059] Table 2 Sizing performance test results

[0060]

[0061] It can be seen from Table 2 that, compared with Comparative Examples 1-3, the sizing performance of Examples 1-3 of the present invention is significantly better.

[0062] Test Example 2: Biodegradation Rate of Different Slurries

[0063] Experimental objects: Examples 1-3 and Comparative Examples 1-3

[0064] Experimental method: GB / T41010-2021 standard was adopted to simulate the biological decomposition process of slurry in a natural aqueous environment.

[0065] Experimental results: as shown in Table 3.

[0066] Table 3 Biodegradation rate results of different slurries

[0067]

[0068]

[0069] It can be seen from the results in Table 3 that, compared with Comparative Examples 1-3, the slurry degradation rates of Examples 1-3 of the present invention are significantly improved.

[0070] Anything not described in detail in the present invention is well known to those skilled in the art.

[0071] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified and replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing an environmentally friendly slurry, characterized in that: The method comprises the following steps: A polylactic acid-co-glycolic acid copolymer is dissolved in a co-solvent at a mass-to-volume ratio of 1 g:10-30 mL and stirred until completely dissolved to obtain a mixed solution, then the mixed solution is heated to 80-100° C. and the temperature is maintained constant, and a rare earth metal compound is added to the solution while stirring. After the addition is complete, the temperature is lowered to 40-60° C. and kept warm for 2-5 hours. After the insulation is completed, the solution is cooled to room temperature, and the unreacted rare earth metal compound is filtered out to obtain a modified polylactic acid-co-glycolic acid copolymer solution; the mixed solution and the rare earth metal compound are added at a volume-to-mass ratio of 100 mL:1-5 g; Ultrasonic dispersion of epoxy resin in a mixture of an organic solvent / citrate buffer solution, followed by addition of organosilane and stirring the mixture at 100-120° C. for 1-3 hours. After the reaction is completed, a saturated sodium bicarbonate solution is slowly added dropwise to the product solution until the pH of the solution reaches 7-7.

5. The modified polylactic acid-glycolic acid copolymer solution and the diamino compound obtained above are then added in sequence. The solution is stirred at 35-45° C. for 8-12 hours, cooled naturally, allowed to stand for 12-18 hours, and then filtered. The resulting solution is an environmentally friendly slurry. In the above reaction process, the epoxy resin and the organosilane are added in a volume ratio of 1-3 mL: 0.1-0.5 mL; the product solution, the modified polylactic acid-glycolic acid copolymer solution and the diamino compound are added in a volume mass ratio of 1 mL: 5-10 mL: 0.04-0.08 g; The organosilane is one or a mixture of two or more of methyltrimethoxysilane, tetramethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, ethyltriethoxysilane and tetrapropoxysilane; The diamino compound is one or more selected from 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, p-phenylenediamine, m-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene, and o-tolidine.

2. The method according to claim 1, characterized in that The polylactic acid-glycolic acid copolymer consists of 60-80% of lactic acid and 20-40% of glycolic acid.

3. The method according to claim 1, characterized in that The co-solvent is any one of chloroform, dichloromethane, tetrahydrofuran, acetone and ethyl acetate.

4. The method according to claim 1, wherein The rare earth metal compound is selected from the chloride, hydroxide, nitrate, carbonate or sulfate of any one or more rare earth metals.

5. The method according to claim 4, characterized in that The rare earth metal is selected from any one of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

6. The method according to claim 1, characterized in that The epoxy resin is selected from any one of bisphenol S epoxy resin, bisphenol F epoxy resin, bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, and novolac epoxy resin, or a mixture of two or more thereof; the molecular weight of the epoxy resin is 4000-8000.

7. The method according to claim 1, characterized in that The organic solvent / citrate buffer mixture is prepared by mixing 30-50% by volume of the organic solvent and 50-70% by volume of the citrate buffer.

8. The method according to claim 7, characterized in that The organic solvent is selected from one or a mixture of two or more of N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

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