Degradable protective film and method for preparing the same

Abstract

The application relates to a degradable protective film and a preparation method thereof, and belongs to the technical field of degradable protective film preparation. The protective film comprises the following raw materials in parts by weight: 75-85 parts of a biodegradable base material, 15-25 parts of an auxiliary material, and 0-3 parts of an auxiliary agent; the auxiliary material is prepared through polymerization reaction of A3 monomers, isocyanate group terminated linear fatty polyester and glycidol; and the A3 monomers are prepared through reaction of formaldehyde and 2-amino benzene mercaptan. The auxiliary material prepared through polymerization reaction of A3 monomers, isocyanate group terminated linear fatty polyester and glycidol is introduced, the temperature resistance and toughness of the finally obtained protective film are improved, and the technical problems mentioned in the background art are solved.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable protective film preparation technology, specifically, it relates to a biodegradable protective film and its preparation method. Background Technology

[0002] Protective films are widely used on the outer layers of products across various industries to enhance their protection against impacts, damage, water, corrosion, and UV rays. However, with the updating or replacement of these protected products, corresponding protective films become obsolete, leading to their accumulation. This accumulation undoubtedly burdens the environment; therefore, biodegradable protective films represent a new trend in the field of protective film manufacturing technology. Biodegradable protective films belong to biodegradable plastics, which can be completely degraded by naturally occurring microorganisms in environments such as soil, seawater, freshwater, and compost, transforming into carbon dioxide (CO2) and / or methane (CH4), water (H2O), and mineralized inorganic salts of their constituent elements, making them environmentally safe and harmless. Existing biodegradable plastics generally utilize biodegradable plastics (such as polycaprolactone (PCL) and polylactic acid (PLA)) to replace or partially replace traditional plastic raw materials and then fabricate them into films.

[0003] However, since the toughness and temperature resistance of PCL and PLA are often lower than those of traditional plastic raw materials, the toughness and temperature resistance of protective films made by relying on biodegradable plastics to replace or partially replace traditional plastic raw materials cannot meet the protective function requirements of the protective film. Summary of the Invention

[0004] The purpose of this invention is to provide a biodegradable protective film and its preparation method.

[0005] The technical problem to be solved by this invention is to address the issue that the toughness and temperature resistance of existing protective films made by relying on biodegradable plastics to replace or partially replace traditional plastic raw materials cannot meet the protective function requirements of protective films.

[0006] The first objective of this invention can be achieved through the following technical solution:

[0007] A biodegradable protective film comprises the following raw materials in parts by weight: 75-85 parts of biodegradable base material, 15-25 parts of auxiliary material, and 0-3 parts of auxiliaries.

[0008] Furthermore, the excipient is produced by polymerization of A3 monomer, isocyanate-terminated linear fatty polyester and glycidyl ether; the A3 monomer is produced by reaction of formaldehyde and 2-aminobenzenethiol.

[0009] Furthermore, the reaction between formaldehyde and 2-aminobenzenethiol is specifically carried out as follows:

[0010] After mixing formaldehyde aqueous solution, 2-aminobenzenethiol and the first organic solvent evenly, the mixture is heated to 65-70℃ and kept at this temperature for 4-12 hours. The reaction is then stopped, the solvent is recovered by rotary evaporation, and the mixture is washed and dried to obtain monomer A3.

[0011] Furthermore, the first organic solvent is one of ethanol, glycerol, and tetrahydrofuran; preferably, it is ethanol.

[0012] Furthermore, the molar ratio of formaldehyde to 2-aminobenzenethiol is 1:1.

[0013] Furthermore, the mass ratio of the A3 monomer (417), isocyanate-terminated linear fatty polyester, and glycidyl (74) is 8:80-180:2.5-3.

[0014] In this invention, the 1,3,5-triazine structure formed by the reaction of amino groups and formaldehyde in the A3 monomer, and the benzene structure linked to the 1,3,5-triazine structure, are both rigid structures. Using this rigid structure as the hard chain of the excipient, and the linear fatty polyester chain in the isocyanate-terminated linear fatty polyester as the soft chain, an excipient capable of toughening, strengthening, and rigidifying is prepared. This excipient is introduced into the biodegradable matrix to improve the toughness of the final protective film. Simultaneously, the high-temperature resistance of the triazine structure also endows the excipient with high-temperature resistance enhancement properties, further enhancing its performance when introduced into the biodegradable matrix. In the decomposition of the base material, the temperature resistance of the final protective film is improved, thereby solving the problems mentioned in the background art and enabling the protective function of the final protective film to meet the protective performance requirements. Moreover, the linear aliphatic polyester chain is biodegradable, therefore, the excipients in this invention are biodegradable. Furthermore, the excipients in this invention are hyperbranched polymers with lower viscosity, better flowability, and active end groups (epoxy groups), which have good compatibility with biodegradable base materials and do not require the introduction of compatibilizers. At the same time, their active end groups (epoxy groups) promote the curing and film formation during the preparation of the protective film.

[0015] Furthermore, the preparation of the excipients includes:

[0016] After uniformly mixing A3 monomer, isocyanate-terminated linear fatty polyester, second organic solvent and first catalyst, the mixture is heated to a second reaction temperature and reacted for a second time period at the second reaction temperature. Then glycidyl is added and reacted for a third time period at a third reaction temperature. The reaction is then terminated and after post-treatment, the excipient is obtained.

[0017] Further, the second organic solvent is one of chloroform, benzene, and toluene; preferably, it is chloroform.

[0018] Furthermore, the first catalyst is one of the organotin catalysts.

[0019] Furthermore, the second reaction temperature is 50-65℃.

[0020] Furthermore, the second time period is 2-6 hours.

[0021] Furthermore, the third time period is 3-6 hours.

[0022] Furthermore, the isocyanate-terminated linear fatty polyester is prepared by a capping reaction of a linear fatty polyester made by reacting 1,6-adipic acid and 1,4-butanediol with terephthalic diisocyanate.

[0023] Furthermore, the molar ratio of 1,6-adipic acid and 1,4-butanediol is 1:1.5-2.

[0024] Furthermore, the reaction conditions for the 1,6-adipic acid and 1,4-butanediol are as follows: under the presence of a third organic solvent and an esterification catalyst, the reaction temperature is 90-150℃ and the reaction time is 4-10h.

[0025] Furthermore, the third organic solvent is one of tetrahydrofuran, chloroform, benzene, and toluene.

[0026] Furthermore, the reaction conditions for the end-capping reaction are as follows: under the conditions of a fourth organic solvent and an organotin catalyst, the reaction temperature is 50-70℃ and the reaction time is 2-6h.

[0027] Furthermore, the fourth organic solvent is one of acetone, chloroform, benzene, and toluene.

[0028] Furthermore, the relative molecular mass of the isocyanate-terminated linear fatty polyester is 3000-5000, preferably 3000-4000 or 4000-5000.

[0029] Furthermore, the biodegradable base material is polycaprolactone and / or polylactic acid.

[0030] As a further embodiment of the technical solution of the present invention, the biodegradable base material is composed of polycaprolactone and modified polycaprolactone mixed in a mass ratio of 10:0-2, wherein the content of modified polycaprolactone is 0 or more.

[0031] As a further embodiment of the technical solution of the present invention, the modified polycaprolactone is prepared by reacting a fluorinated amino polymer with caprolactone monomer.

[0032] As a further embodiment of the present invention, the fluorinated amino polymer is prepared by free radical polymerization of hexafluorobutyl acrylate and 4-vinylaniline.

[0033] As a further embodiment of the technical solution of the present invention, the mass ratio of hexafluorobutyl acrylate to 4-vinylaniline is 30-50:50-70.

[0034] As a further embodiment of the technical solution of the present invention, the reaction conditions for the reaction of hexafluorobutyl acrylate and 4-vinylaniline are: 60-90℃ and 6-12h.

[0035] As a further embodiment of the technical solution of the present invention, the relative molecular mass of the fluorinated amino polymer is 3000-6000, preferably 3000-4000, 4000-5000 or 5000-6000.

[0036] In a further embodiment of the present invention, fluorinated branches are introduced into the molecular chain of modified polycaprolactone by introducing fluorinated amino polymers, thereby endowing the protective film with additional corrosion resistance.

[0037] As a further aspect of the technical solution of the present invention, the copolymerization reaction of the fluorinated amino polymer and the caprolactone monomer includes:

[0038] After uniformly mixing the fluorinated amino polymer, caprolactone monomer, organotin catalyst and fifth organic solvent, the mixture was stirred and reacted at 100-140℃ for 12-24 hours under nitrogen protection. The reaction was then stopped, and after post-treatment, modified polycaprolactone was obtained.

[0039] As a further embodiment of the technical solution of the present invention, the fifth organic solvent is one of N,N-dimethylformamide, toluene, and xylene.

[0040] As a further embodiment of the technical solution of the present invention, the mass ratio of the fluorinated amino polymer to the caprolactone monomer is 2-4:10.

[0041] Furthermore, the auxiliary agent is one or more of antioxidants and / or lubricants.

[0042] The antioxidants or lubricants mentioned are additives well-known in the field of this invention, and the present invention does not limit their types.

[0043] The second objective of this invention can be achieved through the following technical solution:

[0044] A method for preparing a biodegradable protective film, comprising:

[0045] After the biodegradable base material, auxiliary materials and additives are mixed evenly, a mixture is obtained. The mixture is then processed into a film by blowing film machine or by melt casting and rapid cooling to obtain a biodegradable protective film.

[0046] The beneficial effects of this invention are:

[0047] This invention improves the temperature resistance and toughness of the final protective film by introducing an auxiliary material made from A3 monomer, isocyanate-terminated linear fatty polyester and glycidyl ether through polymerization, thus solving the technical problems mentioned in the background art. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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.

[0049] Example 1

[0050] Preparation of fluorinated amino polymers:

[0051] Hexafluorobutyl acrylate and 4-vinylaniline were added to benzene at a mass ratio of 30:70, along with an initiator (AI BN, with an added mass of 1.5% of the total mass of hexafluorobutyl acrylate and 4-vinylaniline). After stirring and mixing evenly, the mixture was heated to 80°C and kept at this temperature with stirring for 6 hours. The reaction was then stopped, the mixture was rotary evaporated, deionized water was added to precipitate the precipitate, and the mixture was dried to obtain a fluorinated amino polymer. Subsequently, the relative molecular mass of the obtained fluorinated amino polymer was measured to be 3600.

[0052] Example 2

[0053] Preparation of fluorinated amino polymers:

[0054] Hexafluorobutyl acrylate and 4-vinylaniline were added to benzene at a mass ratio of 50:50, along with an initiator (AI BN, with an added mass of 2.5% of the total mass of hexafluorobutyl acrylate and 4-vinylaniline). The mixture was stirred and mixed thoroughly under nitrogen protection, then heated to 85°C and stirred for 12 hours. The reaction was then stopped, the mixture was rotary evaporated, deionized water was added to precipitate the precipitate, and the mixture was dried to obtain a fluorinated amino polymer. The relative molecular mass of the obtained fluorinated amino polymer was measured to be 5500.

[0055] Example 3

[0056] Preparation of isocyanate-terminated linear fatty polyesters:

[0057] X1. Mix 0.1 mol 1,6-adipic acid, 0.15 mol 1,4-butanediol, 0.8 g p-toluenesulfonic acid and 100 mL chloromethane evenly, heat to 105 °C, and stir for 8 h. Then, evaporate by rotary evaporation, wash with water, and dry to obtain linear fatty polyester.

[0058] X2. The linear fatty polyester obtained in step X1, terephthalic diisocyanate (in excess, the molar mass of which is equal to the molar mass of 1,4-butanediol added, i.e., the amount added is 0.15 mol), 1.1 g of dibutyltin dilaurate and 150 mL of acetone are mixed evenly, and the mixture is stirred at 60 °C for 3 h under nitrogen protection. The reaction is then stopped, and the mixture is washed and dried to obtain isocyanate-terminated linear fatty polyester (relative molecular mass of 3500).

[0059] Example 4

[0060] Preparation of isocyanate-terminated linear fatty polyesters:

[0061] X1. Mix 0.1 mol 1,6-adipic acid, 0.2 mol 1,4-butanediol, 0.8 g p-toluenesulfonic acid and 100 mL chloromethane evenly, heat to 120 °C, and stir for 8 h. Then, evaporate by rotary evaporation, wash with water, and dry to obtain linear fatty polyester.

[0062] X2. The linear fatty polyester obtained in step X1, terephthalic diisocyanate (in excess, the molar mass of which is equal to the molar mass of 1,4-butanediol added, i.e., the amount added is 0.2 mol), 1.2 g of dibutyltin dilaurate and 150 mL of acetone are mixed evenly, and the mixture is stirred at 65 °C under nitrogen protection for 6 h. The reaction is then stopped, the mixture is washed and dried to obtain isocyanate-terminated linear fatty polyester (relative molecular mass of 4000).

[0063] Example 5

[0064] Preparation of excipients:

[0065] i. Mix formaldehyde aqueous solution (mass fraction 37%, containing 0.1 mol formaldehyde), 0.1 mol 2-aminobenzylthiol and 100 mL ethanol evenly, heat to 70 °C and keep the reaction at this temperature for 4 h, stop the reaction, rotary evaporate the solvent, wash and dry to obtain monomer A3.

[0066] ii. Mix 8g of A3 monomer, 120g of isocyanate-terminated linear fatty polyester prepared in Example 3, 200mL of chloroform and 2.2g of stannous octoate evenly, heat to 60°C and keep warm for 3h, then add 2.5g of glycidyl ether and react for 3h for the third time period, then stop the reaction, rotary evaporate, wash and obtain excipient.

[0067] Example 6

[0068] Preparation of excipients:

[0069] i. Mix formaldehyde aqueous solution (mass fraction 37%, containing 0.1 mol formaldehyde), 0.1 mol 2-aminobenzylthiol and 100 mL ethanol evenly, heat to 65 °C and keep the reaction at this temperature for 12 h, stop the reaction, rotary evaporate the solvent, wash and dry to obtain monomer A3.

[0070] ii. Mix 8g of A3 monomer, 130g of isocyanate-terminated linear fatty polyester prepared in Example 4, 200mL of chloroform and 2.3g of stannous octoate evenly, heat to 65°C and keep warm for 2h, then add 3g of glycidyl ether and react for 3-6h in the third time period, then stop the reaction, rotary evaporate, wash and obtain excipient.

[0071] Example 7

[0072] Preparation of modified polycaprolactone:

[0073] 20g of the fluorinated amino polymer prepared in Example 1, 100g of caprolactone monomer, 2.5g of stannous octoate and 150mL of N,N-dimethylformamide were mixed evenly and stirred at 140°C for 12h under nitrogen protection. The reaction was then stopped, and the mixture was rotary evaporated and dried to obtain modified polycaprolactone.

[0074] Example 8

[0075] Preparation of modified polycaprolactone:

[0076] 40g of the fluorinated amino polymer prepared in Example 2, 100g of caprolactone monomer, 2.5g of stannous octoate and 150mL of N,N-dimethylformamide were mixed evenly and stirred at 100°C for 24h under nitrogen protection. The reaction was then stopped, and the mixture was rotary evaporated and dried to obtain modified polycaprolactone.

[0077] Example 9

[0078] Preparation of protective film:

[0079] Prepare the raw materials according to the proportions in Table 1. Then heat the prepared raw materials (80-120℃) and mix them evenly to obtain a mixture. Then use a blown film machine to form a film to obtain a biodegradable protective film.

[0080] Table 1 (parts by weight)

[0081]

[0082] Comparative Example 1

[0083] Preparation of protective film:

[0084] Prepare the raw materials according to the proportions in Table 2. Then heat and mix the prepared raw materials evenly to obtain a mixture. Use a blown film machine to form a film to obtain a biodegradable protective film.

[0085] Table 2 (parts by weight)

[0086]

[0087]

[0088] In Comparative Example 1-1, the polylactic acid film was fragile during the blown film process and could not form a complete film.

[0089] The protective films obtained in Example 9, Comparative Examples 1-2, and Comparative Examples 1-3 were subjected to physical property tests, and the test results are shown in Table 3. In the degradation rate test, the composting time was 180 days.

[0090] Table 3

[0091]

[0092] As can be seen from the data in Table 3, the films obtained in Examples 9-1 to 9-5 of the present invention have good tensile elongation at break, degradation performance and heat resistance.

[0093] 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.

[0094] The above description is merely an example and illustration 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 invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A biodegradable protective film, characterized in that, The raw materials include the following parts by weight: 75-85 parts of biodegradable base material, 15-25 parts of excipients, and 0-3 parts of auxiliary agents; The excipients are made by polymerization of A3 monomer, isocyanate-terminated linear fatty polyester and glycidyl ether. The A3 monomer is prepared by reacting formaldehyde and 2-aminophenylthiol. The reaction of formaldehyde and 2-aminophenylthiol is specifically carried out as follows: Formaldehyde aqueous solution, 2-aminophenylthiol, and the first organic solvent are mixed evenly, heated to 65-70℃, and the reaction is maintained at this temperature for 4-12 hours. The reaction is then stopped, the solvent is recovered by rotary evaporation, and the mixture is washed and dried to obtain monomer A3. The molar ratio of formaldehyde to 2-aminobenzenethiol is 1:1; The mass ratio of the A3 monomer, isocyanate-terminated linear fatty polyester, and glycidyl is 8:80-180:2.5-3.

2. The biodegradable protective film according to claim 1, characterized in that, The preparation of the excipients includes: After uniformly mixing A3 monomer, isocyanate-terminated linear fatty polyester, second organic solvent and first catalyst, the mixture is heated to a second reaction temperature and reacted for a second time period at the second reaction temperature. Then glycidyl is added and reacted for a third time period at a third reaction temperature. The reaction is then terminated and after post-treatment, the excipient is obtained.

3. The biodegradable protective film according to claim 2, characterized in that, The second organic solvent is one of chloroform, benzene, and toluene; the first catalyst is one of organotin catalysts; the second reaction temperature is 50-65℃; the second time period is 2-6h; and the third time period is 3-6h.

4. The biodegradable protective film according to claim 1, characterized in that, The isocyanate-based capped linear fatty polyester is prepared by capping a linear fatty polyester made from the reaction of 1,6-adipic acid and 1,4-butanediol with terephthalic diisocyanate.

5. The biodegradable protective film according to claim 4, characterized in that, The molar ratio of 1,6-adipic acid to 1,4-butanediol is 1:1.5-2. The reaction conditions for 1,6-adipic acid and 1,4-butanediol are: under the third organic solvent and esterification catalyst, the reaction temperature is 90-150℃ and the reaction time is 12-24h. The reaction conditions for the end-capping reaction are: under the fourth organic solvent and organotin catalyst, the reaction temperature is 50-70℃ and the reaction time is 4-12h.

6. The biodegradable protective film according to claim 1, characterized in that, The biodegradable base material is polycaprolactone and / or polylactic acid.

7. The biodegradable protective film according to claim 1, characterized in that, The biodegradable base material is composed of polycaprolactone and modified polycaprolactone mixed in a mass ratio of 10:0-2; the modified polycaprolactone is prepared by reacting a fluorinated amino polymer and caprolactone monomer; the fluorinated amino polymer is prepared by free radical polymerization of hexafluorobutyl acrylate and 4-vinylaniline.

8. A method for preparing a biodegradable protective film according to any one of claims 1-7, characterized in that, include: After the biodegradable base material, excipients and additives are mixed evenly, a mixture is obtained. The mixture is then made into a film to obtain a biodegradable protective film.

Images