Degradable protective film and preparation method thereof

Abstract

The invention relates to a degradable protective film and a preparation method thereof, and belongs to the technical field of preparation of degradable protective films. 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 from an A3 monomer, isocyanate-terminated linear aliphatic polyester and glycidol through a polymerization reaction; and the monomer A3 is prepared from formaldehyde and 2-aminobenzenethiol through a reaction. By introducing the auxiliary material prepared from the A3 monomer, the isocyanate-terminated linear aliphatic polyester and the glycidol through the polymerization reaction, the temperature resistance and the toughness of the finally obtained protective film are improved, and the technical problems mentioned in the background technology are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of degradable protective films, and in particular, relates to a degradable protective film and a preparation method thereof. Background Art

[0002] Protective films are widely used as the outer layer of products in various industries to improve the products' protection against collision, damage, water, corrosion or UV. However, with the renewal or replacement of the protected products, the corresponding protective films are discarded, resulting in the accumulation of discarded protective films. These accumulated protective films undoubtedly put a burden on the environment. Therefore, degradable protective films are a new trend in the field of protective film preparation technology. Degradable protective films are degradable plastics. This type of plastic can be completely degraded by microorganisms existing in nature into carbon dioxide (CO 2 ) or / and methane (CH 4 ), water (H 2 O) and the mineralized inorganic salts of the elements it contains, etc., are safe and harmless to the environment. Existing degradable plastics generally use biodegradable plastics (such as polycaprolactone (PCL), polylactic acid (PLA)) to replace or partially replace traditional plastic raw materials and make 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 replacing biodegradable plastics or partially using traditional plastic raw materials cannot meet the protective function requirements of the protective films. Summary of the invention

[0004] The object of the present invention is to provide a degradable protective film and a preparation method thereof.

[0005] The technical problem to be solved by the present invention is to solve the problem that the toughness and temperature resistance of the existing protective film made by replacing biodegradable plastics or partially traditional plastic raw materials cannot meet the protective function requirements of the protective film.

[0006] The first object of the present invention can be achieved by the following technical solutions:

[0007] A degradable 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.

[0008] Furthermore, the auxiliary material is prepared by polymerization reaction of A3 monomer, isocyanate-terminated linear fatty polyester and glycidol; and the A3 monomer is prepared by reaction of formaldehyde and 2-aminobenzenethiol.

[0009] Furthermore, the reaction of formaldehyde and 2-aminobenzenethiol is specifically performed as follows:

[0010] After the formaldehyde aqueous solution, 2-aminobenzenethiol and the first organic solvent are uniformly mixed, the mixture is heated to 65-70° C. and kept warm for reaction for 4-12 hours. The reaction is stopped, the solvent is recovered by rotary evaporation, and the mixture is washed and dried to obtain A3 monomer.

[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), the isocyanate-terminated linear fatty polyester, and the glycidol (74) is 8:80-180:2.5-3.

[0014] In the present invention, the 1,3,5-triazine structure formed by the reaction of amino group and formaldehyde in the A3 monomer and the benzene structure connected to the 1,3,5-triazine structure are used, both of which are rigid structures. This rigid structure is used as the hard chain of the auxiliary material, and the linear fatty polyester chain in the isocyanate-terminated linear fatty polyester is used as the soft chain to prepare an auxiliary material capable of toughening and strengthening and rigidity enhancement, which is introduced into the degradable biodegradable base material to improve the toughness of the final protective film. At the same time, the high temperature resistance of the triazine structure also gives the auxiliary material a high temperature resistance enhancement characteristic, and the auxiliary material is introduced into the degradable biodegradable base material. The excipients in the present invention are biodegradable, and thus the heat resistance of the protective film finally obtained is improved, thereby solving the problems mentioned in the background technology, and the protective function of the protective film finally obtained can meet the protective performance requirements; moreover, the linear fatty polyester chain is biodegradable, therefore, the excipients in the present invention are biodegradable; and, the excipients in the present invention are hyperbranched polymers, have lower viscosity, better fluidity and active end groups (epoxy groups), have good compatibility with biodegradable base materials, and do not need to introduce a compatibilizer. At the same time, its active end groups (epoxy groups) promote the curing and film formation during the preparation of the protective film.

[0015] Furthermore, the preparation of the auxiliary material includes:

[0016] The A3 monomer, the isocyanate-terminated linear fatty polyester, the second organic solvent and the first catalyst are uniformly mixed, heated to a second reaction temperature, and reacted at the second reaction temperature for a second period of time, then glycidol is added, and reacted at a third reaction temperature for a third period of time, the reaction is terminated, and after post-treatment, an auxiliary material is obtained.

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

[0018] Furthermore, the first catalyst is an organotin catalyst.

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

[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 prepared by the reaction of 1,6-adipic acid and 1,4-butanediol and p-phenylene diisocyanate.

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

[0024] Furthermore, the reaction conditions of the 1,6-hexanediol and 1,4-butanediol are: in the presence of a third organic solvent and an esterification catalyst, the reaction temperature is 90-150° C., and the reaction time is 4-10 hours.

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

[0026] Furthermore, the reaction conditions of the end-capping reaction are: in the presence of a fourth organic solvent and an organic tin catalyst, the reaction temperature is 50-70° C., and the reaction time is 2-6 hours.

[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 solution 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, and the content of the modified polycaprolactone is greater than 0.

[0031] As a further solution of the technical solution of the present invention, the modified polycaprolactone is prepared by reacting a fluorine-containing chain amino polymer and a caprolactone monomer.

[0032] As a further solution of the technical solution of the present invention, the fluorine-containing chain amino polymer is prepared by free radical polymerization of hexafluorobutyl acrylate and 4-vinylaniline.

[0033] As a further solution 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 solution of the technical solution of the present invention, in the reaction of hexafluorobutyl acrylate and 4-vinylaniline, the reaction conditions are: 60-90° C. and the reaction time is 6-12 hours.

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

[0036] In a further embodiment of the technical solution of the present invention, fluorine-containing chain amino polymers are introduced into the molecular chains of modified polycaprolactone to impart the protective film with an additional function of corrosion resistance.

[0037] As a further embodiment of the technical solution of the present invention, the copolymerization reaction of the fluorine-containing chain amino polymer and the caprolactone monomer comprises:

[0038] After uniformly mixing the fluorine-containing chain amino polymer, caprolactone monomer, organic tin catalyst and the fifth organic solvent, stirring and reacting for 12-24 hours at 100-140° C. under nitrogen protection, stopping the reaction, and post-treating to obtain modified polycaprolactone.

[0039] As a further solution 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 solution of the technical solution of the present invention, the mass ratio of the fluorine-containing chain amino polymer to the caprolactone monomer is 2-4:10.

[0041] Furthermore, the auxiliary agent is one or more of an antioxidant and / or a lubricant.

[0042] The antioxidant or lubricant is an additive well known in the art, and the invention does not limit its type.

[0043] The second object of the present invention can be achieved by the following technical solutions:

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

[0045] After the biodegradable base material, auxiliary materials and adjuvants are uniformly mixed to obtain a mixture, the mixture is passed through a film blowing machine or melt casting to be quenched into a film to obtain a degradable protective film.

[0046] Beneficial effects of the present invention:

[0047] The invention improves the heat resistance and toughness of the protective film finally obtained by introducing auxiliary materials prepared by polymerization reaction of A3 monomer, isocyanate-terminated linear fatty polyester and glycidol, thereby solving the technical problems mentioned in the background technology. DETAILED DESCRIPTION

[0048] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0049] Example 1

[0050] Preparation of fluorinated chain amino polymers:

[0051] Hexafluorobutyl acrylate and 4-vinylaniline were added to benzene in a mass ratio of 30:70, and an initiator (AI BN, the added mass was 1.5% of the total mass of hexafluorobutyl acrylate and 4-vinylaniline) was added, and after stirring and mixing evenly, the mixture was heated to 80°C and stirred for 6 hours. The reaction was stopped, and the mixture was rotary evaporated, deionized water was added for precipitation, and the mixture was dried to obtain a fluorine-containing chain amino polymer. Subsequently, the relative molecular mass of the obtained fluorine-containing chain amino polymer was measured to be 3600.

[0052] Example 2

[0053] Preparation of fluorinated chain amino polymers:

[0054] Hexafluorobutyl acrylate and 4-vinylaniline were added to benzene in a mass ratio of 50:50, and an initiator (AI BN, the added mass was 2.5% of the total mass of hexafluorobutyl acrylate and 4-vinylaniline) was added. After stirring and mixing evenly under nitrogen protection, the mixture was heated to 85° C. and stirred for 12 hours. The reaction was stopped, rotary evaporated, deionized water was added for precipitation, and dried to obtain a fluorine-containing chain amino polymer. Subsequently, the relative molecular mass of the obtained fluorine-containing chain amino polymer was measured to be 5500.

[0055] Example 3

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

[0057] X1. Mix 0.1 mol 1,6-hexanediol, 0.15 mol 1,4-butanediol, 0.8 g p-toluenesulfonic acid and 100 mL methyl chloride, heat to 105°C, stir and react for 8 hours, rotary evaporate, wash with water and dry to obtain linear fatty polyester;

[0058] X2. Evenly mix the linear fatty polyester obtained in step X1, p-phenylene diisocyanate (excess, the molar mass added is equal to the molar mass of 1,4-butanediol added, i.e., the added amount is 0.15 mol), 1.1 g of dibutyltin dilaurate and 150 mL of acetone, stir and react for 3 h at 60 ° C under nitrogen protection, stop the reaction, wash and dry to obtain an isocyanate-terminated linear fatty polyester (relative molecular mass is 3500).

[0059] Example 4

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

[0061] X1. Mix 0.1 mol 1,6-hexanediol, 0.2 mol 1,4-butanediol, 0.8 g p-toluenesulfonic acid and 100 mL methyl chloride, heat to 120°C, stir and react for 8 hours, rotary evaporate, wash with water and dry to obtain linear fatty polyester;

[0062] X2. Evenly mix the linear fatty polyester obtained in step X1, p-phenylene diisocyanate (excess, the molar mass added is equal to the molar mass of 1,4-butanediol added, i.e., the added amount is 0.2 mol), 1.2 g of dibutyltin dilaurate and 150 mL of acetone, stir and react for 6 h at 65 ° C under nitrogen protection, stop the reaction, wash and dry to obtain an isocyanate-terminated linear fatty polyester (relative molecular mass 4000).

[0063] Example 5

[0064] Preparation of excipients:

[0065] i. After uniformly mixing a formaldehyde aqueous solution (mass fraction of 37%, containing 0.1 mol formaldehyde), 0.1 mol 2-aminobenzenethiol and 100 mL ethanol, the mixture was heated to 70° C. and kept warm for 4 h. The reaction was stopped, the solvent was recovered by rotary evaporation, and the mixture was washed and dried to obtain A3 monomer;

[0066] ii. After 8g of A3 monomer, 120g of the isocyanate-terminated linear fatty polyester prepared in Example 3, 200mL of chloroform and 2.2g of stannous octoate were mixed uniformly, heated to 60°C, and kept warm for 3h, followed by adding 2.5g of glycidol and reacting for 3h in the third time period, the reaction was terminated, rotary evaporated, washed, and the auxiliary material was obtained.

[0067] Example 6

[0068] Preparation of excipients:

[0069] i. After uniformly mixing a formaldehyde aqueous solution (mass fraction of 37%, containing 0.1 mol formaldehyde), 0.1 mol 2-aminobenzenethiol and 100 mL ethanol, the mixture was heated to 65° C. and kept warm for 12 h. The reaction was stopped, the solvent was recovered by rotary evaporation, and the mixture was washed and dried to obtain A3 monomer;

[0070] ii. After 8g A3 monomer, 130g of the isocyanate-terminated linear fatty polyester prepared in Example 4, 200mL of chloroform and 2.3g of stannous octoate were mixed uniformly, heated to 65°C, and kept warm for 2h, followed by adding 3g of glycidol and reacting for 3-6h in the third time period, the reaction was terminated, rotary evaporated, washed, and the auxiliary material was obtained.

[0071] Example 7

[0072] Preparation of modified polycaprolactone:

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

[0074] Example 8

[0075] Preparation of modified polycaprolactone:

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

[0077] Example 9

[0078] Preparation of protective film:

[0079] The raw materials are prepared according to the raw material ratio in Table 1, and then the prepared raw materials are heated (80-120° C.) and mixed evenly to obtain a mixture, and the mixture is formed into a film by a film blowing machine to obtain a degradable protective film.

[0080] Table 1 (parts by weight)

[0081]

[0082] Comparative Example 1

[0083] Preparation of protective film:

[0084] The raw materials are prepared according to the raw material ratio in Table 2, and then the prepared raw materials are heated and mixed evenly to obtain a mixture, and the mixture is formed into a film by a film blowing machine to obtain a degradable protective film.

[0085] Table 2 (parts by weight)

[0086]

[0087]

[0088] Among them, during the polylactic acid film blowing process in Comparative Example 1-1, the film was fragile and could not form a complete film.

[0089] The protective films obtained in Example 9 and Comparative Examples 1-2 and 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] From the data in Table 3, it can be seen that the films obtained from 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 the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0094] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A degradable protective film, characterized in that: The composition 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 auxiliary agent; The auxiliary material is prepared by polymerization reaction of A3 monomer, isocyanate-terminated linear fatty polyester and glycidol; The A3 monomer is prepared by reacting formaldehyde and 2-aminobenzenethiol.

2. A degradable protective film according to claim 1, characterized in that: The mass ratio of the A3 monomer, the isocyanate-terminated linear fatty polyester and glycidol is 8:80-180:2.5-3.

3. The degradable protective film according to claim 1, characterized in that: The preparation of the auxiliary material comprises: The A3 monomer, the isocyanate-terminated linear fatty polyester, the second organic solvent and the first catalyst are uniformly mixed, heated to a second reaction temperature, and reacted at the second reaction temperature for a second period of time, then glycidol is added, and reacted at a third reaction temperature for a third period of time, the reaction is terminated, and after post-treatment, an auxiliary material is obtained.

4. A degradable protective film according to claim 3, characterized in that: The second organic solvent is one of chloroform, benzene and toluene; the first catalyst is one of organic tin catalysts; the second reaction temperature is 50-65°C; the second time period is 2-6h; and the third time period is 3-6h.

5. The degradable protective film according to claim 1, characterized in that: The molar ratio of the formaldehyde to 2-aminobenzenethiol is 1:

1.

6. The degradable protective film according to claim 1, characterized in that: The isocyanate-terminated linear fatty polyester is prepared by a terminal reaction of a linear fatty polyester prepared by the reaction of 1,6-adipic acid and 1,4-butanediol and p-phenylene diisocyanate.

7. A degradable protective film according to claim 6, characterized in that: The molar ratio of the 1,6-hexanedioic acid to 1,4-butanediol is 1:1.5-2, and the reaction conditions of the 1,6-hexanedioic acid and 1,4-butanediol are: in the third organic solvent and the esterification reaction catalyst, the reaction temperature is 90-150°C, and the reaction time is 12-24h; the reaction conditions of the end-capping reaction are: in the fourth organic solvent and the organic tin catalyst, the reaction temperature is 50-70°C, and the reaction time is 4-12h.

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

9. The degradable 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 fluorine-containing chain amino polymer and a caprolactone monomer; and the fluorine-containing chain amino polymer is prepared by a free radical polymerization reaction of hexafluorobutyl acrylate and 4-vinylaniline.

10. A method for preparing a degradable protective film according to any one of claims 1 to 9, characterized in that: include: The biodegradable base material, auxiliary materials and adjuvants are uniformly mixed to obtain a mixture, and the mixture is made into a film to obtain a degradable protective film.

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