CN115304735A

CN115304735A - Nano chitin-based polyurethane and preparation method thereof

Info

Publication number: CN115304735A
Application number: CN202211135468.2A
Authority: CN
Inventors: 石聪灿; 王韬; 黄燕香; 唐桂明; 朱伯承; 江瑶; 江学亮
Original assignee: Guangdong Ruipeng Material Science Co ltd
Current assignee: Guangdong Ruipeng Material Science Co ltd
Priority date: 2022-09-19
Filing date: 2022-09-19
Publication date: 2022-11-08

Abstract

The invention relates to a bio-based polyurethane produced by taking catering waste, namely shrimp shells or crab shells as a raw material, belongs to the cross field of high added value utilization of biomass resources and polyurethane technology, and discloses a nanochitin-based polyurethane and a preparation method thereof. The nanometer chitin-based polyurethane comprises the following raw materials in parts by weight: 80-120 parts of nanochitin, 30-60 parts of polyisocyanate, 5-10 parts of oligomer polyol, 5-30 parts of chain extender, 5-15 parts of acid compound, 10-20 parts of organic amine compound, 20-50 parts of oxime compound, 10-30 parts of ethylene glycol and 80-120 parts of deionized water. The nano-chitin reacts with isocyanate to realize multi-site net-shaped crosslinking of molecular chains of polyurethane, so that the mechanical property of a polyurethane film formed by heating is improved.

Description

Nano chitin-based polyurethane and preparation method thereof

Technical Field

The invention discloses a nano-chitin-based polyurethane and a preparation method thereof, in particular relates to a bio-based polyurethane produced by taking catering waste, namely shrimp shells or crab shells as raw materials, and belongs to the cross field of high-added-value utilization of biomass resources and polyurethane coating technology.

Background

Polyurethane, a full name of which is polyurethane, is a high molecular compound, which was produced in 1937 by otto bayer or the like. Polyurethanes fall into the two main categories of polyester and polyether. The soft polyurethane mainly has a thermoplastic linear structure, and has better stability, chemical resistance, rebound resilience and mechanical property and smaller compression deformability than a PVC foaming material. Good heat insulation, sound insulation, shock resistance and gas defense performance, thus being used as packaging, sound insulation and filtering materials. The hard polyurethane plastic has the advantages of light weight, excellent sound insulation and heat insulation performance, chemical resistance, good electrical property, easy processing and low water absorption rate, and is mainly used for building, automobile and aviation industries and heat-insulating structural materials. The polyurethane elastomer has the performance between that of plastic and rubber, and has the advantages of oil resistance, wear resistance, low temperature resistance, aging resistance, high hardness and elasticity. Is mainly used in the shoe making industry and the medical industry. The polyurethane can also be used for preparing adhesives, coatings, synthetic leather and the like. However, the traditional polyurethane synthetic raw materials come from petroleum-based and other non-renewable resources, certain pollution is caused to the environment, and the development of green degradable bio-based polyurethane to replace the traditional polyurethane has important practical application value.

Chitin, also known as chitin and chitin, is a polysaccharide substance extracted from the shells of marine crustaceans, is the second largest bio-based green resource in the world, second only to cellulose. The chitin and the derivatives thereof can be used as the reinforcing filler of the coating, and can also be used as the synthetic raw material of coating resin or a film-forming substance. After deacetylation and protonation treatment, molecular chains of the chitin contain a large number of primary amine groups, so that the chitin and acrylic acid are easy to generate polymerization reaction, and a reticular molecular chain is formed, so that the performances such as strength after film forming are improved. The research on novel renewable and environment-friendly coatings has profound and important significance for the development of the coating industry in China.

Disclosure of Invention

The invention aims to provide a nano chitin-based polyurethane and a preparation method thereof, in particular to a bio-based polyurethane produced by taking catering waste, namely shrimp shells or crab shells as raw materials.

A nano chitin-based polyurethane is composed of the following raw materials in parts by weight: 80-120 parts of nano chitin, 30-60 parts of polyisocyanate, 5-10 parts of oligomer polyol, 5-30 parts of chain extender, 5-15 parts of acid compound, 10-20 parts of organic amine compound, 20-50 parts of oxime compound and 80-120 parts of deionized water.

In some embodiments, the nanochitin-based polyurethane comprises the following raw materials in parts by weight: 90-110 parts of nano chitin, 40-60 parts of polyisocyanate, 5-10 parts of oligomer polyol, 5-25 parts of chain extender, 5-10 parts of acid compound, 10-20 parts of organic amine compound, 20-40 parts of oxime compound and 90-120 parts of deionized water.

In some of these embodiments, the preparation of the nanochitin comprises the steps of:

(1) Impurity removal: soaking shrimp shells or crab shells collected in the seafood market in 5wt% sodium hydroxide solution for 12-24 hours, then washing the shrimp shells or the crab shells with water, and drying at 80-100 ℃ to obtain chitin;

(2) Crushing: crushing chitin by using a crusher, and screening by using a 60-mesh sieve;

(3) Deacetylation: soaking the crushed chitin in 30wt% sodium hydroxide solution, reacting at the constant temperature of 80-100 ℃ for 12-24 hours, then filtering, washing filter residues with distilled water until the filtrate is neutral, and taking the filter residues to obtain deacetylated chitin;

(4) Protonation: adding a proper amount of water into deacetylated chitin, slowly dripping glacial acetic acid, adjusting the pH value of the mixed solution to 3-3.5, reacting at room temperature for 3-6 hours, and filtering to remove filtrate to obtain chitin;

(5) Homogenizing: dispersing the chitin by a high-pressure homogenizer to obtain the nano chitin.

In some of these embodiments, the polyisocyanate is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl cyanuric acid.

In some of these embodiments, the oligomer polyol is polytetrahydrofuran ether glycol, polypropylene glycol, and the polyester polyol mainly comprises at least one of polyhexamethylene glycol adipate, polycarbonate diol, polybutylene adipate, polycaprolactone diol, and polypropylene glycol.

In some of these embodiments, the chain extender is at least one of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, glycerol, trimethylolpropane, 1,4-cyclohexanediol, 2,2-dimethylolbutyric acid, 2,2-dimethylolpropionic acid, oleic diethanolamide.

In some of these embodiments, the acid compound is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and benzoic acid.

In some of these embodiments, the organic amine compound is at least one of diethanolamine, triethanolamine, methyldiethanolamine, diisopropylamine, 1,2-dimethylpropylamine, 1,2-propanediamine, 1,4-butanediamine, and hexanediamine.

In some of these embodiments, the oxime based compound is at least one of acetaldoxime, dimethylketoxime, dimethylglyoxime, butyraldoxime.

The invention also provides a preparation method of the nano chitin-based polyurethane, which comprises the following steps: adding polyisocyanate and oligomer polyol into a multifunctional reaction kettle according to the formula weight, stirring at the rotating speed of 300-500 revolutions per minute, introducing nitrogen for 5-20 minutes to remove air in the reaction kettle, heating to 80-100 ℃, reacting at constant temperature for 0.5-1 hour, adding a chain extender, quickly heating to 105-110 ℃, adding an oxime compound, reacting for half an hour, adding an organic amine compound, continuously reacting at constant temperature for 1-2 hours, adding an acid compound, continuously reacting for 1-3 hours, cooling to 25 ℃, and stirring and reacting for 2-3 hours at the rotating speed of 1000-1500 revolutions per minute; then introducing nitrogen for 20-30 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 80-100 ℃, reducing the stirring speed to 200-500 r/min, adding nano chitin, reacting for 2-5 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce the viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain the nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film.

The invention has the following advantages:

(1) The shrimp shell and the crab shell are mostly discarded as wastes, and the shrimp shell and the crab shell are used as production raw materials, so the production cost is low;

(2) The solvent in the formula is a mixture of water and polyethylene glycol, so that the solvent is less harmful to human bodies, belongs to a green solvent, does not generate gas harmful to human health in the subsequent use of polyurethane, and accords with the production concept of green environmental protection;

(3) The shrimp shells and the crab shells are utilized in a high-valued manner, so that the carbon emission of the shrimp shells and the crab shells in the traditional utilization mode is reduced;

(4) The nano chitin can be used as a filler to enhance the film forming strength of polyurethane, and each unit of a molecular chain at least contains one primary amine group, and can be used as a reaction center to react with the polybasic isocyanic acid to form a net-shaped cross-link, so that the film forming strength of the polyurethane is improved.

Drawings

FIG. 1 atomic force microscopy of nanochitins prepared in example 1;

FIG. 2 stretch profile of polyurethane film prepared in example 2;

FIG. 3 stretch profile of polyurethane film prepared in example 3;

FIG. 4 stretch profile of polyurethane film prepared in example 4;

FIG. 5 stretch profile of polyurethane film prepared in example 5;

FIG. 6 stretch profile of polyurethane film prepared in example 6;

FIG. 7 stretch profile of polyurethane film prepared in example 7.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings, technical process steps, specific implementation conditions and materials in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

Soaking shrimp shells or crab shells collected in a seafood market in a 5wt% sodium hydroxide solution for 18 hours, then washing the shrimp shells or the crab shells clean with water, and drying at 90 ℃ to obtain chitin; crushing chitin by using a crusher, and screening by using a 60-mesh sieve; soaking the crushed chitin in 25wt% sodium hydroxide solution, reacting at the constant temperature of 90 ℃ for 18 hours, then filtering, washing filter residue with distilled water until the filtrate is neutral, and taking the filter residue to obtain deacetylated chitin; adding a proper amount of water into deacetylated chitin, slowly dripping glacial acetic acid, adjusting the pH value of the mixed solution to 3, reacting at room temperature for 4.5 hours, and filtering to remove filtrate to obtain chitin; dispersing the chitin by a high-pressure homogenizer to obtain the nano chitin. As shown in FIG. 1, the shape of the chitosan is tested by an atomic force microscope, and the length of the chitosan is 180-700 nm, and the width of the chitosan is about 20-30 nm.

Example 2

Table 1 example 2 raw material ratio for polyurethane synthesis

Nano chitin	80 portions
		Hexamethylene diisocyanate	45 portions of
Tetrahydrofuranether glycols	5 portions of
		1,4 butanediol	15 portions of
Formic acid	5 portions of
		Triethanolamine	10 portions of
Acetaldoxime	20 portions of
		Deionized water	100 portions of

Adding hexamethylene diisocyanate and tetrahydropalmiran glycol into a multifunctional reaction kettle according to the mass part ratio shown in table 1, stirring at the rotating speed of 300 revolutions per minute, introducing nitrogen for 20 minutes to remove air in the reaction kettle, heating to 100 ℃, reacting at constant temperature for 0.5 hour, adding 1,4-butanediol, quickly heating to 105 ℃, adding acetaldehyde oxime, reacting for half an hour, adding triethanolamine, reacting at constant temperature for 1 hour, adding formic acid, reacting for 3 hours, cooling to 25 ℃, and stirring at the rotating speed of 1200 revolutions per minute for reacting for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 100 ℃, reducing the stirring speed to 300 revolutions per minute, adding nano chitin, reacting for 3 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce the viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nanochitin polyurethane film was tested by a universal tester, and as shown in fig. 2, the tensile strength of the polyurethane film reached 95.1MPa.

Example 3

TABLE 2 EXAMPLE 3 raw material ratios for polyurethane Synthesis

Nano chitin	90 portions of
		Diphenylmethane diisocyanate	50 portions of
Polypropylene glycol	10 portions of
		Ethylene glycol	10 portions of
Benzoic acid	10 portions of
		Diethanolamine (DEA)	10 portions of
Dimethyl ketoxime	30 portions of
		Deionized water	120 portions of

In a multifunctional reaction kettle, adding diphenylmethane diisocyanate and polypropylene glycol according to the mass part ratio shown in Table 2, stirring at the rotating speed of 300-500 rpm, introducing nitrogen for 20 minutes to remove air in the reaction kettle, heating to 100 ℃, reacting at constant temperature for 0.5-1 hour, adding ethylene glycol, quickly heating to 105 ℃, adding dimethylketoxime, reacting for half an hour, adding diethanolamine, continuing to react at constant temperature for 2 hours, adding benzoic acid, continuing to react for 3 hours, cooling to 25 ℃, and stirring and reacting at the rotating speed of 1500 rpm for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 100 ℃, reducing the stirring speed to 500 r/min, adding nano chitin, reacting for 4 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nanochitin polyurethane film was measured by a universal tester, and as a result, as shown in fig. 3, the tensile strength of the polyurethane film reached 115.8MPa.

Example 4

TABLE 3 EXAMPLE 4 raw Material proportioning for polyurethane Synthesis

Nano chitin	120 portions of
		Isophorone diisocyanate	60 portions of
Polyhexanediol adipate	10 portions of
		Trimethylolpropane	20 portions of
Hydrochloric acid	5 portions of
		Methyldiethanolamine	15 portions of
Dimethylglyoxime	40 portions of
		Deionized water	120 portions of

Adding isophorone diisocyanate and poly (hexanediol adipate) according to the mass part ratio shown in the table 3 into a multifunctional reaction kettle, stirring at the rotating speed of 300-500 revolutions per minute, introducing nitrogen for 15 minutes to remove air in the reaction kettle, heating to 90 ℃, reacting at constant temperature for 0.5 hour, adding trimethylolpropane, quickly heating to 105 ℃, adding dimethylglyoxime, reacting for half an hour, adding methyldiethanolamine, reacting at constant temperature for 1 hour, adding hydrochloric acid, reacting for 2 hours, cooling to 25 ℃, and stirring at the rotating speed of 1000 revolutions per minute for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 100 ℃, reducing the stirring speed to 200 revolutions per minute, adding nano chitin, reacting for 5 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce the viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nano chitin polyurethane film is tested by a universal tester, and the result is shown in figure 4, and the tensile strength of the polyurethane film can reach 100.8MPa.

Example 5

TABLE 4 example 5 raw material ratio of synthetic acrylic resin

Nano chitin	100 portions of
		Toluene diisocyanate	50 portions of
Polycarbonate diol	10 portions of
		2,2-Dimethylolpropionic acid	10 portions of
Acetic acid	10 portions of
		1,2-propanediamine	20 portions of
Dimethyl ketoxime	30 portions of
		Deionized water	100 portions of

Adding toluene diisocyanate and polycarbonate diol into a multifunctional reaction kettle according to the mass part ratio shown in Table 4, stirring at the rotating speed of 500 revolutions per minute, introducing nitrogen for 20 minutes to remove air in the reaction kettle, heating to 100 ℃, reacting at constant temperature for 1 hour, adding 2,2-dimethylolpropionic acid, quickly heating to 110 ℃, adding dimethyl ketoxime, reacting for half an hour, adding 1,2-propanediamine, reacting at constant temperature for 2 hours, adding acetic acid, reacting for 1 hour, cooling to 25 ℃, and stirring at the rotating speed of 1500 revolutions per minute for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 100 ℃, reducing the stirring speed to 400 revolutions per minute, adding nano chitin, reacting for 4 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce the viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nanochitin polyurethane film was measured by a universal tester, and as a result, as shown in fig. 5, the tensile strength of the polyurethane film reached 71.8MPa.

Example 6

TABLE 5 EXAMPLE 6 raw material compounding ratio for acrylic resin synthesis

Nano chitin	80 portions
		Polymethylene polyphenyl cyanuric acid	40 portions of
Polybutylene adipate	5 portions of
		1,4-cyclohexanediol	10 portions of
Phosphoric acid	10 portions of
		Hexamethylene diamine	10 portions of
Dimethylglyoxime	40 portions of
		Deionized water	120 portions of

Adding polymethylene polyphenyl polycyanate and poly butylene adipate into a multifunctional reaction kettle according to the mass part ratio of Table 5, stirring at the rotating speed of 500 revolutions per minute, introducing nitrogen for 20 minutes to remove air in the reaction kettle, heating to 100 ℃, reacting at constant temperature for 0.5-1 hour, adding 1,4-cyclohexanediol, quickly heating to 110 ℃, adding dimethylglyoxime, reacting for half an hour, adding hexamethylene diamine, continuously reacting at constant temperature for 1 hour, adding phosphoric acid, continuously reacting for 2 hours, cooling to 25 ℃, and stirring at the rotating speed of 1500 revolutions per minute for reacting for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 100 ℃, reducing the stirring speed to 500 r/min, adding nano chitin, reacting for 5 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nanochitin polyurethane film was measured by a universal tester, and as a result, as shown in fig. 6, the tensile strength of the polyurethane film reached 91.6MPa.

Example 7

TABLE 6 example 7 raw material ratio for synthesizing acrylic resin

Nano chitin	120 portions of
		Dicyclohexylmethane diisocyanate	60 portions of
Polycaprolactone diol	10 portions of
		Glycerol	25 portions of
Sulfuric acid	15 portions of
		1,2-Dimethylpropylamine	20 portions of
Dimethyl ketoxime	50 portions of
		Deionized water	120 portions of

Adding dicyclohexylmethane diisocyanate and polycaprolactone diol into a multifunctional reaction kettle according to the mass part ratio shown in the table 6, stirring at the rotating speed of 400 revolutions per minute, introducing nitrogen for 20 minutes to remove air in the reaction kettle, heating to 90 ℃, reacting at constant temperature for 0.5 hour, adding glycerol, quickly heating to 110 ℃, adding dimethylketoxime, reacting for half an hour, adding 1,2-dimethylpropylamine, reacting at constant temperature for 2 hours, adding sulfuric acid, reacting for 3 hours, cooling to 25 ℃, and stirring at the rotating speed of 1200 revolutions per minute for 2 hours; then introducing nitrogen for 20 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 90 ℃, reducing the stirring speed to 500 revolutions per minute, adding nano chitin, reacting for 3 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce viscosity, dispersing and emulsifying in a high-speed dispersion machine, and distilling under reduced pressure to remove water to obtain nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film. The tensile strength of the nanochitin polyurethane film was measured by a universal tester, and as a result, as shown in fig. 7, the tensile strength of the polyurethane film reached 112.9MPa.

The skilled person should understand that: although the invention has been described in terms of the above specific embodiments, the inventive concept is not limited thereto and any modification applying the inventive concept is intended to be included within the scope of the patent claims.

Claims

1. The nano chitin-based polyurethane is characterized by comprising the following raw materials in parts by weight: 80-120 parts of nano chitin, 30-60 parts of polyisocyanate, 5-10 parts of oligomer polyol, 5-30 parts of chain extender, 5-15 parts of acid compound, 10-20 parts of organic amine compound, 20-50 parts of oxime compound and 80-120 parts of deionized water.

2. The nanochitin-based polyurethane of claim 1, wherein the nanochitin is prepared by the steps of:

(3) Deacetylation: soaking the crushed chitin in 20-30 wt% sodium hydroxide solution, reacting at the constant temperature of 80-100 ℃ for 12-24 hours, then filtering, washing filter residue with distilled water until the filtrate is neutral, and taking the filter residue to obtain deacetylated chitin;

3. The nanochitin-based polyurethane of claim 1, wherein the polyisocyanate is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and polymethylene polyphenyl polyisocyanate.

4. Nanochitin-based polyurethane according to claim 1, wherein the oligomeric polyol is polytetrahydrofuran ether glycol, polypropylene glycol, polyester polyol mainly comprising at least one of polyhexamethylene glycol adipate, polycarbonate glycol, polybutylene adipate, polycaprolactone glycol, polypropylene glycol.

5. The nanochitin-based polyurethane of claim 1, wherein the chain extender is at least one of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, glycerol, trimethylolpropane, 1,4-cyclohexanediol, 2,2-dimethylolbutyric acid, 2,2-dimethylolpropionic acid, oleic acid diethanolamide.

6. The nanochitin-based polyurethane of claim 1, wherein the acid compound is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and benzoic acid.

7. The nanochitin-based polyurethane of claim 1, wherein the organic amine compound is at least one of diethanolamine, triethanolamine, methyldiethanolamine, diisopropylamine, 1,2-dimethylpropylamine, 1,2-propylenediamine, 1,4-butylenediamine, and hexamethylenediamine.

8. The nanochitin-based polyurethane of claim 1, wherein the oxime-based compound is at least one of acetaldoxime, dimethylketoxime, dimethylglyoxime, butyraldehyde oxime.

9. A process for the preparation of nanochitin-based polyurethane according to any one of claims 1 to 8, comprising the steps of:

adding polyisocyanate and oligomer polyol into a multifunctional reaction kettle, stirring at the rotating speed of 300-500 revolutions per minute, introducing nitrogen for 5-20 minutes to remove air in the reaction kettle, heating to 80-100 ℃, reacting at constant temperature for 0.5-1 hour, adding a chain extender, quickly heating to 105-110 ℃, adding an oxime compound, reacting for half an hour, adding ethylene glycol, continuing to react at constant temperature for 1-2 hours, sequentially adding an acid compound and an organic amine compound, continuing to react for 1-3 hours, cooling to 25 ℃, and stirring and reacting for 2-3 hours at the rotating speed of 1000-1500 revolutions per minute; then introducing nitrogen for 20-30 minutes, removing water vapor generated in the reaction kettle due to reaction, rapidly heating to 80-100 ℃, reducing the stirring speed to 200-500 r/min, adding nano chitin, reacting for 2-5 hours at constant temperature, pouring out the reactant from the reaction kettle, adding deionized water to reduce the viscosity, dispersing and emulsifying in a high-speed dispersion machine, and removing water by reduced pressure distillation to obtain the nano chitin-based polyurethane emulsion; and coating the glass plate with nano chitin-based polyurethane and curing to obtain the nano chitin-based polyurethane film.