Preparation method of environment-friendly paper bag
By modifying the surface of squid ink particles and preparing a coating film using specific chemical substances, the problems of easy coating peeling, poor wear resistance, and difficulty in achieving both breathability and waterproofing in paper bag materials during waterproofing treatment were solved, thus realizing the breathability, waterproofing, and biodegradability of environmentally friendly paper bags.
Patent Information
- Application Number
- CN202511046795.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-10-17
AI Technical Summary
Existing paper bag materials have problems in waterproofing treatment, such as incompatibility between the coating and the paper substrate, easy peeling, poor abrasion resistance, and difficulty in achieving both breathability and waterproofing.
Using squid ink particles as raw material, modified squid ink particles are prepared by surface modification treatment and combining them with tetraethyl orthosilicate and perfluoroalkylalkoxysilane. These particles are then combined with modified glycidyl ester, dianhydride and alicyclic diamine to form a film-forming material, which is sprayed onto base paper to form a coating film. By utilizing the high-density core and low-density shell structure of squid ink particles, both breathability and waterproof performance are achieved.
The prepared environmentally friendly paper bags have good waterproof, breathable and degradable properties, as well as certain oil-proof properties. The coating is degradable in high-temperature acidic environments, and the coating has good flexibility and wear resistance.
Smart Images
Figure SMS_1
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of packaging material preparation, in particular to a preparation method of an environmentally friendly paper bag. BACKGROUND
[0002] As one of the most common packaging materials in life, paper bags have the characteristics of wide raw material sources, easy processing, easy degradation and recycling, and are increasingly popular with consumers and the market in the packaging field, and have considerable and sustainable development potential in the future. As a packaging material, the fibers in the paper have certain strength and structure, and the chemical additives in the sizing or surface coating of the pulp can help improve the final printability, mechanical strength and barrier properties of water, grease and other properties of the paper packaging to improve its packaging effect and quality. Since paper is mainly composed of natural plant fibers, hydrophilic cellulose and hemicellulose are its main chemical components, and there are a large number of hydroxyl groups in the molecular structure, resulting in a loose and porous paper structure with certain liquid absorption. Generally, it needs to be waterproofed. Compared with other packaging materials, paper packaging materials have special applications in some application fields, and higher air permeability is beneficial to improve packaging production efficiency and ensure the balance of air pressure inside and outside the package to prevent package breakage and expansion.
[0003] For the current paper bag material, the following problems exist: first, the waterproof coating treatment of the paper bag has the problems of mismatch between the coating and the paper base, easy peeling and poor wear resistance; second, the waterproof coating treatment almost completely covers the air permeability of the paper itself, and it is difficult to have both air permeability and waterproof performance; third, the waterproof coating hinders the degradation of the paper bag. SUMMARY
[0004] In view of at least one of the above problems, the present application provides a preparation method of an environmentally friendly paper bag.
[0005] The purpose of the present application is achieved by the following technical scheme: A preparation method of an environmentally friendly paper bag, comprising the following steps: (1) Take cuttlefish ink and dilute it with an ethanol aqueous solution, centrifuge and wash, dry, and then disperse it in a surfactant solution, remove the precipitate after standing for 1-4h, centrifuge the solution layer to separate the precipitate, and then wash and dry, and then heat to 130-200℃ under a protective atmosphere and keep for 0.5-2h, and then cool to obtain cuttlefish ink particles; (2) Disperse the cuttlefish ink particles in ethanol, add an ammonia solution, and under the condition of vigorous stirring, add tetraethyl orthosilicate and perfluoroalkylalkoxysilane, continue to stir for 3-6h, centrifuge the precipitate, and then wash with anhydrous ethanol and ethyl acetate, and dry to obtain modified cuttlefish ink particles; (3) Weigh the epoxy propyl alcohol and dissolve it in tetrahydrofuran, add diisocyanate under a protective atmosphere, and keep stirring at 30-50°C for 24-40 hours. After the reaction is completed, remove the solvent by evaporation under reduced pressure to obtain product A; dissolve the product A in a solvent, add diglycidyl ester, diacid anhydride and alicyclic diamine, and keep stirring until they are uniformly dispersed and dissolved. Then keep stirring at 110-135°C for 5-60 minutes to obtain a prepolymer solution; (4) Disperse the modified cuttlefish ink particles in the prepolymer solution, spray them on the base paper after degassing, and dry them at 150-180°C to obtain the product.
[0006] In some preferred embodiments, the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, alkyl phenol polyoxyethylene ether, and sodium ethylene ether sulfate.
[0007] In some preferred embodiments, the concentration of the surfactant solution is 0.5-5 wt%.
[0008] In some preferred embodiments, the dispersion ratio of the cuttlefish ink particles to the ethanol in step (2) is 1:(40-50).
[0009] In some preferred embodiments, the concentration of the ammonia solution is 28 wt%, and the volume ratio of the ethanol to the ammonia solution is (4-5):1.
[0010] In some preferred embodiments, the mass ratio of the cuttlefish ink particles to the tetraethyl orthosilicate and perfluoroalkyl alkoxysilane is 1:(0.1-0.3):(1-1.5).
[0011] In some preferred embodiments, the perfluoroalkyl alkoxysilane is one or more of perfluorooctyl trimethoxysilane, perfluorodecyl trimethoxysilane, perfluorooctyl triethoxysilane, perfluorodecyl triethoxysilane, perfluorooctyl dimethyl methoxysilane, and perfluorodecyl dimethyl methoxysilane.
[0012] In some preferred embodiments, the diisocyanate in step (3) is one or more of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexyl methane diisocyanate, toluene diisocyanate, and 4,4'-diphenyl methane diisocyanate.
[0013] In some preferred embodiments, the molar ratio of the epoxy propyl alcohol to the diisocyanate is 2:1.
[0014] In some preferred embodiments, the mass ratio of the product A to the diglycidyl ester, the diacid anhydride and the cycloaliphatic diamine is 1: (2-2.8): (2.7-3.6): (0.48-0.8).
[0015] In some preferred embodiments, the diglycidyl ester is one or more of 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, dimer acid diglycidyl ester.
[0016] In some preferred embodiments, the diacid anhydride is one or more of phthalic anhydride, maleic anhydride, dimethyl maleic anhydride, 2-methyl-3-propyl maleic anhydride.
[0017] In some preferred embodiments, the cycloaliphatic diamine is one or more of isophorone diamine, cyclohexane diamine, methylcyclohexane diamine, 4,4'-diaminodicyclohexyl methane.
[0018] In some preferred embodiments, the dispersion concentration of the modified cuttlefish ink particles in the prepolymer solution is 0.05-0.3 g / mL.
[0019] In some preferred embodiments, the solid content of the prepolymer solution is 28-56%.
[0020] In some preferred embodiments, the spraying amount of the base paper is 2-25 mL / m 2 .
[0021] The beneficial effects of the present application are: In view of the problems of the paper bag waterproof treatment in the prior art, such as difficult to have both air permeability and waterproof performance, easy to fall off the coating, poor wear resistance, difficult to degrade and the like, the application provides a preparation method of an environmentally friendly paper bag, taking the ink particles of proper particle size of cuttlefish as raw materials, and modifying the ink particles with tetraethyl orthosilicate and perfluorodecyltriethoxysilane, taking modified glycidyl ether, diglycidyl ester, diacid anhydride and alicyclic diamine as a film forming material, so as to obtain a paper bag material with good waterproof performance, air permeability and degradability, and also with a certain degree of oil resistance, wherein the ink particles of cuttlefish have a two-layer structure of high-density inner core and low-density outer shell, and after being stabilized by heat treatment and then being surface treated, the high-density inner core provides mechanical support, and the low-density outer shell is used for surface treatment and provides air permeability, so that the coating has both air permeability and waterproof performance, the ink of cuttlefish is a viscous suspension liquid composed of black particles invisible to the naked eye, and there are about 200mg particles in every milliliter of the ink, i.e. 20% (W / V), the ink particles of cuttlefish are spherical, and the diameter varies between 90-250nm, the fresh ink of cuttlefish contains water, pigment, protein, saccharide, lipid and the like, the black particles have a two-layer structure of high-density inner core and low-density outer shell, the inner core is cuttlefish melanin, the melanin is a polymer of indolequinone, and is combined with or not combined with protein, and the outer core part is a protein polysaccharide compound connected to the melanin; further, the application takes modified glycidyl ether, diglycidyl ester, diacid anhydride and alicyclic diamine as a film forming material, the coating has the characteristic structures of epoxy resin, polyester and polyurethane, and gives the coating good flexibility and wear resistance, and the coating can also be degraded by ester exchange in a high-temperature acidic environment, and has good degradability. DETAILED DESCRIPTION
[0022] The application is further described in combination with the following examples. Example 1
[0023] A preparation method of an environmentally friendly paper bag, comprising the following steps: (1) taking ink of cuttlefish, diluting in 60% ethanol aqueous solution, centrifugal washing 3 times, drying, dispersing the dried ink powder in 1.3wt% sodium dodecyl benzene sulfonate solution, removing the precipitate after standing for 2h, centrifuging (8000rpm x 30min) the solution layer, separating the precipitate, and then washing and drying the precipitate, and then heating to 160℃ under a protective atmosphere and keeping for 40min, and then cooling to obtain ink particles of cuttlefish; (2) The cuttlefish ink particles are dispersed in anhydrous ethanol, 28% ammonia solution is added, tetraethyl orthosilicate and perfluorodecyl triethoxysilane are added under the condition of 800 rpm intense stirring, stirring is continued for 4 h, the precipitate is separated by centrifugation, the precipitate is washed with anhydrous ethanol and ethyl acetate in turn, and the modified cuttlefish ink particles are obtained after drying; the dispersion ratio of the cuttlefish ink particles to the anhydrous ethanol is 1:45, the volume ratio of the anhydrous ethanol to the ammonia solution is 4.5:1; the mass ratio of the cuttlefish ink particles to the tetraethyl orthosilicate and perfluorodecyl triethoxysilane is 1:0.2:1.25; (3) Epoxypropanol is weighed and dissolved in tetrahydrofuran, hexamethylene diisocyanate is added under a protective atmosphere, and the reaction is stirred at 40°C for 28 h; after the reaction is completed, the tetrahydrofuran is removed by evaporation under reduced pressure to obtain product A; the product A is dissolved in a xylene solvent, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic anhydride and isophorone diamine are added, and the mixture is uniformly dispersed and dissolved by stirring and heating; the mixture is stirred and heated at 125°C for 30 min to obtain a prepolymer solution; the molar ratio of the epoxypropanol to the hexamethylene diisocyanate is 2:1; the mass ratio of the product A to the 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, the phthalic anhydride and the isophorone diamine is 1:2.44:3.03:0.68, and the solid content of the prepolymer solution is 48%; (4) The modified cuttlefish ink particles are dispersed in the prepolymer solution, and the mixture is sprayed on a base paper after degassing, and dried at 160°C to obtain a paper bag; the dispersion concentration of the modified cuttlefish ink particles in the prepolymer solution is 0.12 g / mL, and the spraying amount of the base paper is 6 mL / m 2 . Example 2
[0024] A paper bag preparation method comprises the following steps: (1) Take cuttlefish ink, dilute with 60% ethanol aqueous solution, centrifugal wash 3 times, dry, disperse the dried ink powder in 1.3 wt% sodium dodecyl benzene sulfonate solution, remove the precipitate after standing for 2 h, centrifugal separate (8000 rpm x 30 min) the solution layer, separate the precipitate, wash, dry and cool the precipitate to obtain cuttlefish ink particles; (2) The squid ink particles were dispersed in anhydrous ethanol, 28% ammonia solution was added, and tetraethyl orthosilicate and perfluorodecyltriethoxysilane were added under vigorous stirring at 800 rpm, and stirring was continued for 4 hours. The precipitate was separated by centrifugation, and the precipitate was washed with anhydrous ethanol and ethyl acetate in turn, and dried to obtain modified squid ink particles; the dispersion ratio of the squid ink particles to the anhydrous ethanol was 1:45, the volume ratio of the anhydrous ethanol to the ammonia solution was 4.5:1; the mass ratio of the squid ink particles to the tetraethyl orthosilicate and perfluorodecyltriethoxysilane was 1:0.2:1.25; (3) Weigh glycidol and dissolve it in tetrahydrofuran, add hexamethylene diisocyanate under a protective atmosphere, and react at 40°C with stirring for 28 hours. After the reaction is completed, remove tetrahydrofuran under reduced pressure to obtain product A; dissolve the product A in xylene solvent, add 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic anhydride and isophorone diamine, heat and stir until uniformly dispersed and dissolved, and stir at 125°C for 30 minutes to obtain a prepolymer solution; the molar ratio of the glycidol to the hexamethylene diisocyanate is 2:1; the mass ratio of the product A to the 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, the phthalic anhydride and the isophorone diamine is 1:2.44:3.03:0.68, and the solid content of the prepolymer solution is 48%; (4) The modified squid ink particles are dispersed in the prepolymer solution, sprayed on the base paper after degassing, and dried at 160°C; the dispersion concentration of the modified squid ink particles in the prepolymer solution is 0.12 g / mL, and the spraying amount of the base paper is 6 mL / m 2 . Example 3
[0025] A method for preparing a paper bag comprises the following steps: (1) Nano-silica with a particle size of 90-250 nm was dried and dispersed in a 1.3 wt% sodium dodecylbenzenesulfonate solution. After standing for 2 h, the precipitate was removed. The solution layer was centrifuged (8000 rpm × 30 min) to separate the precipitate. The precipitate was washed and dried, and then heated to 160 ° C under a protective atmosphere and kept warm for 40 min. After cooling, silica particles were obtained. (2) The silica particles are dispersed in anhydrous ethanol, a 28% ammonia solution is added, and tetraethyl orthosilicate and perfluorodecyltriethoxysilane are added under vigorous stirring at 800 rpm, and stirring is continued for 4 hours. The precipitate is separated by centrifugation, and the precipitate is washed with anhydrous ethanol and ethyl acetate in sequence, and dried to obtain modified silica particles; the dispersion ratio of the silica particles to the anhydrous ethanol is 1:45, the volume ratio of the anhydrous ethanol to the ammonia solution is 4.5:1; the mass ratio of the silica particles to the tetraethyl orthosilicate and perfluorodecyltriethoxysilane is 1:0.2:1.25; (3) Weigh glycidol and dissolve it in tetrahydrofuran, add hexamethylene diisocyanate under a protective atmosphere, and react at 40°C with stirring for 28 hours. After the reaction is completed, remove tetrahydrofuran under reduced pressure to obtain product A; dissolve the product A in xylene solvent, add 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic anhydride and isophorone diamine, heat and stir until uniformly dispersed and dissolved, and stir at 125°C for 30 minutes to obtain a prepolymer solution; the molar ratio of the glycidol to the hexamethylene diisocyanate is 2:1; the mass ratio of the product A to the 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, the phthalic anhydride and the isophorone diamine is 1:2.44:3.03:0.68, and the solid content of the prepolymer solution is 48%; (4) The modified silica particles are dispersed in the prepolymer solution, sprayed on the base paper after degassing, and dried at 160°C; the dispersion concentration of the modified silica particles in the prepolymer solution is 0.12 g / mL, and the spraying amount of the base paper is 6 mL / m 2 . Example 4
[0026] A method for preparing a paper bag comprises the following steps: (1) Take squid ink, dilute it with 60% ethanol aqueous solution, centrifuge and wash it three times, dry it, disperse the dried ink powder in 1.3wt% sodium dodecylbenzenesulfonate solution, let it stand for 2 hours, remove the precipitate, take the solution layer and centrifuge it (8000rpm×30min), separate the precipitate, wash and dry the precipitate, then heat it to 160℃ under protective atmosphere and keep it warm for 40min, and cool it to obtain squid ink particles; (2) the cuttlefish ink particles are dispersed in anhydrous ethanol, 28% ammonia water solution is added, tetraethyl orthosilicate and perfluorodecyl triethoxysilane are added under the condition of 800 rpm intense stirring, the stirring is continued for 4 h, the precipitate is separated by centrifugation, the precipitate is washed with anhydrous ethanol and ethyl acetate in sequence, and the modified cuttlefish ink particles are prepared after drying; the dispersion ratio of the cuttlefish ink particles to the anhydrous ethanol is 1:45, the volume ratio of the anhydrous ethanol to the ammonia water solution is 4.5:1; the mass ratio of the cuttlefish ink particles to the tetraethyl orthosilicate and perfluorodecyl triethoxysilane is 1:0.2:1.25; (3) 4,5-epoxy cyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic anhydride and isophorone diamine are added in a xylene solvent, the temperature is increased and stirred until uniformly dispersed and dissolved, the temperature is kept at 125℃ and stirred for 30 min, and a prepolymer solution is obtained; the mass ratio of the 4,5-epoxy cyclohexane-1,2-dicarboxylic acid diglycidyl ester to the phthalic anhydride and the isophorone diamine is 2.44:3.03:0.68, and the solid content of the prepolymer solution is 48%; (4) the modified cuttlefish ink particles are dispersed in the prepolymer solution, sprayed on a base paper after degassing, and dried at 160℃ to obtain the paper bag; the dispersion concentration of the modified cuttlefish ink particles in the prepolymer solution is 0.12 g / mL, and the spraying amount of the base paper is 6 mL / m 2 . Example 5
[0027] A paper bag preparation method comprises the following steps: (1) take cuttlefish ink, dilute with 60% ethanol water solution, centrifugal wash 3 times, dry, disperse the dried ink powder in 1.3wt% sodium dodecyl benzene sulfonate solution, remove the precipitate after standing for 2 h, centrifugal (8000 rpm x 30 min) the solution layer, separate the precipitate, wash and dry the precipitate, then heat to 160℃ and keep for 40 min under a protective atmosphere, and cool to obtain cuttlefish ink particles; (2) the cuttlefish ink particles are dispersed in anhydrous ethanol, 28% ammonia water solution is added, tetraethyl orthosilicate and perfluorodecyl triethoxysilane are added under the condition of 800 rpm intense stirring, the stirring is continued for 4 h, the precipitate is separated by centrifugation, the precipitate is washed with anhydrous ethanol and ethyl acetate in sequence, and the modified cuttlefish ink particles are prepared after drying; the dispersion ratio of the cuttlefish ink particles to the anhydrous ethanol is 1:45, the volume ratio of the anhydrous ethanol to the ammonia water solution is 4.5:1; the mass ratio of the cuttlefish ink particles to the tetraethyl orthosilicate and perfluorodecyl triethoxysilane is 1:0.2:1.25; (3) take epoxy propyl alcohol and dissolve in tetrahydrofuran, under the protection of atmosphere, add hexamethylene diisocyanate, keep warm stirring at 40℃ for 28h, after the reaction is completed, remove tetrahydrofuran under reduced pressure, obtain product A; dissolve the product A in xylene solvent, add 4,5-epoxy cyclohexane-1,2-dicarboxylic acid diglycidyl ester and isophorone diamine, warm stirring to uniformly disperse and dissolve, keep warm stirring at 125℃ for 30min, obtain prepolymer solution; the molar ratio of the epoxy propyl alcohol to the hexamethylene diisocyanate is 2:1; the mass ratio of the product A to the 4,5-epoxy cyclohexane-1,2-dicarboxylic acid diglycidyl ester, the isophorone diamine is 1:2.44:0.68, the solid content of the prepolymer solution is 48%; (4) disperse the modified cuttlefish ink particles in the prepolymer solution, after degassing, spray on base paper, dry at 160℃ to obtain; the dispersion concentration of the modified cuttlefish ink particles in the prepolymer solution is 0.12g / mL, the spraying amount of the base paper is 6mL / m 2 .
[0028] The waterproof and oil-proof performance of the sprayed surface of the paper bag prepared in Examples 1-5 before and after rubbing is measured, a DSA20 type video tension contact angle tester is used to observe the contact angle of water droplets on the surface of the sprayed surface of the paper bag, deionized water and toluene are used as test solutions respectively, the rubbing is specifically that 1500 mesh sandpaper is selected, the coating is abraded by pulling 350mm distance according to the load of 200g, a total of 5 times; the folding resistance of the sprayed surface is also tested (referring to GB / T 457-2008, folding 30 times, observing the coating condition); the air permeability (referring to industry standard QB / T 1460-2006) and the degradation performance (keeping warm at 280℃ for 2h in glacial acetic acid, after washing and drying, weighing, taking the blank control as 100%) of the paper bag before and after spraying are also detected, and the detection results are shown in the following table.
[0029]
[0030] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.
Claims
1. A method for preparing an environmentally friendly paper bag, characterized in that: The following steps are involved: (1) squid ink is diluted with ethanol-water solution, washed by centrifugation, dried, and dispersed in a surfactant solution. The solution layer is allowed to stand for 1-4 hours to remove the precipitate. The solution layer is centrifuged to separate the precipitate. After washing and drying, the solution is heated to 130-200°C under a protective atmosphere and kept warm for 0.5-2 hours. The squid ink particles are obtained after cooling. (2) dispersing the squid ink particles in ethanol, adding an ammonia solution, adding ethyl orthosilicate and perfluoroalkylalkoxysilane under vigorous stirring, continuing stirring for 3-6 hours, centrifuging and separating the precipitate, washing with anhydrous ethanol and ethyl acetate in sequence, and drying to obtain modified squid ink particles; (3) Weigh glycidol and dissolve it in tetrahydrofuran, add diisocyanate under a protective atmosphere, and stir and react at 30-50°C for 24-40 hours. After the reaction is completed, evaporate the solvent under reduced pressure to obtain product A; dissolve the product A in a solvent, add diglycidyl ester, dianhydride and alicyclic diamine, heat and stir until uniformly dispersed and dissolved, and stir and heat at 110-135°C for 5-60 minutes to obtain a prepolymer solution; (4) The modified squid ink particles are dispersed in the prepolymer solution, sprayed on the base paper after degassing, and dried at 150-180°C.
2. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The surfactant is one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and sodium vinyl ether sulfate.
3. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The mass ratio of the squid ink particles to the ethyl orthosilicate and the perfluoroalkylalkoxysilane is 1:(0.1-0.3):(1-1.5).
4. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The perfluoroalkylalkoxysilane is one or more of perfluorooctyltrimethoxysilane, perfluorodecyltrimethoxysilane, perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, perfluorooctyldimethylmethoxysilane, and perfluorodecyldimethylmethoxysilane.
5. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The diisocyanate in step (3) is one or more of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate; and the molar ratio of the glycidol to the diisocyanate is 2:
1.
6. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The mass ratio of the product A to the diglycidyl ester, the dianhydride and the alicyclic diamine is 1:(2-2.8):(2.7-3.6):(0.48-0.8).
7. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The diglycidyl ester is one or more of 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, phthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, and dimer acid diglycidyl ester.
8. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The dianhydride is one or more of phthalic anhydride, maleic anhydride, dimethylmaleic anhydride, and 2-methyl-3-propylmaleic anhydride.
9. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The alicyclic diamine is one or more of isophorone diamine, cyclohexane diamine, methylcyclohexane diamine, and 4,4'-diaminodicyclohexylmethane.
10. The method for preparing an environmentally friendly paper bag according to claim 1, characterized in that: The dispersion concentration of the modified squid ink particles in the prepolymer solution is 0.05-0.3 g / mL.