Chitin-based acrylic resin and preparation method thereof

Abstract

The invention relates to chitin-based acrylic resin and a preparation method thereof, and belongs to the technical field of intersection of high value-added utilization of biomass resources and acrylic resin. The chitin-based acrylic resin is prepared from the following components in parts by weight: 30 to 50 parts of acrylic modified chitin, 20 to 30 parts of acrylic monomer, 10 to 20 parts of polyaldehyde monomer, 5 to 10 parts of polybasic organic amine, 1 to 5 parts of emulsifier, 0.1 to 0.5 part of initiator, 0.2 to 0.4 part of defoaming agent and 80 to 120 parts of deionized water. According to the method, forestry and agricultural residues are used as raw materials, chitin with small molecular chains is obtained through deacetylation treatment, meanwhile, a large number of primary amino groups with high chemical reactivity are exposed on the surfaces of the molecular chains of the chitin, and 3-formyl-2-butenoic acid is further utilized to react with the chitin, so that the yield of the chitin is increased. Acrylic acid groups are successfully grafted to chitin molecular chains to be subjected to polymerization reaction with acrylic acid monomers to form macromolecule resin, meanwhile, the macromolecule resin is subjected to cross reaction with polyaldehyde and polybasic organic amine to generate net-shaped crosslinking, and the strength of the acrylic resin after film forming is improved.

Description

Technical Field

[0001] The present invention belongs to the cross - technical field of high - value utilization of biomass resources and acrylic resins, and particularly relates to a chitin - based acrylic resin and a preparation method thereof. Background Art

[0002] In the mid - 19th century, alkyd resins were synthesized in Germany. In 1912, General Electric Company in the United States made alkyd resins by condensing phthalic anhydride and glycerol to replace the electrical insulating material - shellac. In 1927, R.H. Kienle in the United States developed a manufacturing method for alkyd resins suitable for various uses based on the characteristics that the properties of resins vary depending on polybasic acids. In particular, resins for coatings were manufactured using phthalic anhydride or maleic anhydride, and were industrially produced by General Electric Company in the same year. The output of alkyd resin coatings is very large, accounting for about 20% - 25% of the total coating industry. However, with the continuous development of the scale of human production and life, global oil and gas resources are rapidly decreasing. It is predicted that the world's oil resources will be exhausted within 100 years. Green and renewable bio - based materials have become the most ideal alternative resources for oil and are also important new materials for the development of polymer chemical industry technology.

[0003] In the field of coating applications, bio - based materials, especially vegetable oils, have been widely used to prepare new types of green and environmentally friendly coatings. This is because vegetable oils have the characteristics of non - toxicity, low volatility, biodegradability, and abundant and easily available raw materials. Since the 19th century, a series of studies on vegetable oil - based polymers have been carried out. For example, after the glycerol triester in vegetable oil undergoes glycerol alcoholysis, monoglycerides are obtained for preparing alkyd resins; drying oils or fatty acids are first maleated and then transesterified with epoxy prepolymers to prepare fatty acid - modified epoxy coatings; after epoxidation of soybean oil, it is combined with acrylate to prepare epoxidized soybean oil acrylate resin; monoglycerides are also a kind of polyol and can react with diisocyanates to prepare polyurethanes. Vegetable oils used for preparing water - based polyurethanes include sunflower oil, castor oil, rapeseed oil, soybean oil, etc.; tung oil forms a biodegradable coating directly after thermal cross - linking polymerization. However, as the human dietary demand for vegetable oils is also increasing, using vegetable oils as raw materials for alkyd resins results in relatively high production costs.

[0004] Chitin, also known as chitosan and chitin, is a polysaccharide substance extracted from the shells of marine crustaceans and is the second - largest bio - based green resource in the world, second only to cellulose. Chitin and its derivatives can be used as reinforcing fillers for coatings, and can also be used as raw materials for synthesizing coating resins or film - forming substances. After deacetylation and protonation treatment, the molecular chain of chitin contains a large number of primary amine groups, which are extremely easy to polymerize with acrylic acid and form a network - shaped molecular chain, improving properties such as the strength after film - formation.

[0005] For this reason, the English literature "Preparation and Characterization of Hybrid Chitosan / Acrylic resin Emulsions and Their Films, Tamaki Wada et al, 《Macromolecular Materials and Engineering》, Vol. 291, No. 7, pp. 809 - 819" discloses the preparation of chitosan / acrylic resin emulsion by emulsion polymerization of chitosan and acrylic acid. The specific method is to mix two emulsifiers ER - 20\ER - 30, deionized water, chitosan, methyl methacrylate, and 2 - ethylhexyl acrylate, homogenize them using a homogenizer, then add an initiator to the homogenized solution, stir at 60 °C for 2 hours, and react at 70 °C for two hours to obtain the emulsion. This article uses chitosan as a raw material and utilizes the addition reaction of the amino group of chitosan with acrylic acid. However, this method has two deficiencies. First, the molecular chain of chitosan is relatively large, and when directly reacting with acrylic acid, the chemical reactivity is relatively low. Second, there is no chemical bond connection between chitosans, and a network cross - link cannot be formed, resulting in a relatively low film strength after film formation. Summary of the Invention

[0006] Aiming at the above deficiencies, the purpose of the present invention is to provide a chitin - based acrylic resin and its preparation method, especially using agricultural and forestry waste, namely shrimp shells or crab shells, as raw materials. As Figure 1 shown, chitin is deacetylated to obtain chitosan with a smaller molecular chain, and at the same time, a large number of primary amino groups with high chemical reactivity are exposed on the surface of the chitosan molecular chain. Further, 3 - formyl - 2 - butenoic acid (synthesized by hydrolysis of methyl 3 - formyl - 2 - butenoate (CAS: 96928 - 85 - 7)) is reacted with chitosan, and acrylic acid groups are successfully grafted onto the chitosan molecular chain to polymerize with acrylic acid monomers to form a high - molecular resin. At the same time, cross - reactions are carried out with polyaldehydes and polyamines to generate network cross - links, improving the strength of the acrylic resin film after film formation.

[0007] The specific technical solution is as follows:

[0008] A chitin - based acrylic resin, calculated by weight fraction, the composition of the chitin - based acrylic resin is: 30 - 50 parts of acrylic - modified chitosan, 20 - 30 parts of acrylic acid monomers, 10 - 20 parts of polyaldehyde monomers, 5 - 10 parts of polyamines, 1 - 5 parts of emulsifiers, 0.1 - 0.5 parts of initiators, 0.2 - 0.4 parts of defoamers, and 80 - 120 parts of deionized water; the preparation method of the acrylic - modified chitosan includes the following steps:

[0009] S1 Pretreatment: Wash the collected shrimp and crab shells, dry them in the sun, and grind them into powder to obtain crude chitin. Then, soak 100 - 300 g of chitin in hydrochloric acid with a concentration of 5 - 8 wt% and a volume of 300 - 500 mL, react at a temperature of 20 - 30 °C and a stirring speed of 200 - 500 revolutions per minute for 1 - 3 hours, filter, wash with deionized water until the filtrate is neutral, take the filter residue, and dry it at a temperature of 50 °C; Then, soak 100 - 300 g of the dried chitin powder in a NaOH solution with a concentration of 5 - 10 wt% and a volume of 100 - 300 mL, react at a temperature of 20 - 30 °C and a stirring speed of 500 - 700 revolutions per minute for 1 - 3 hours, filter, wash with deionized water until the filtrate is neutral, take the filter residue, and dry it at a temperature of 50 °C; Finally, soak 100 - 300 g of the alkali-treated and dried chitin in a NaClO solution with a concentration of 0.3 - 0.9 wt%, react at a temperature of 20 - 30 °C and a stirring speed of 500 - 700 revolutions per minute for 1 - 3 hours, filter, wash with deionized water until the filtrate is neutral, take the filter residue, and dry it at a temperature of 50 °C to obtain purified chitin;

[0010] S2 Deacetylation: Soak the purified chitin powder in a NaOH solution with a concentration of 30 - 40 wt% and a volume of 200 - 400 mL for partial deacetylation treatment, and add 0.5 - 1.5 g of NaBH 4 , react at 80 - 90 °C and a stirring speed of 500 - 700 revolutions per minute for 1 - 3 hours, filter, wash with deionized water until the filtrate is neutral, take the filter residue, then drop 1 wt% acetic acid to adjust the pH value of the chitin suspension to 3.0 - 4.0 to obtain a deacetylated chitin solution, i.e., chitosan solution, and store it in a 4 °C environment for later use.

[0011] S3 Acrylic modification of chitosan: By mass fraction, add 10 - 30 parts of chitosan solution, 10 - 20 parts of 3 - formyl - 2 - butenoic acid, and 2 - 5 parts of hydrochloric acid to the multi-functional reaction kettle in sequence. Under a stirring speed of 500 - 1000 revolutions per minute, react the reactants at 30 - 40 °C for 1 - 3 hours, then add NaHCO 3 solution to neutralize the acid in the filter residue, stop the reaction, filter, wash with methanol 3 times, then wash with deionized water until the filtrate is neutral, take the filter residue, and vacuum dry it at 30 - 40 °C to obtain acrylic - modified chitosan.

[0012] In some of the embodiments, the preparation method of the 3 - formyl - 2 - butenoic acid in S3 includes the following steps:

[0013] S4 Add methyl 3-formyl-2-butenoate to a multi-functional reaction kettle, add sodium hydroxide to adjust the pH to 11.6 - 13.8, and react for 2 - 6 hours at a stirring speed of 200 - 500 revolutions per minute and a temperature of 30 - 50 °C;

[0014] S5 Add hydrochloric acid to the solution after the reaction of S4 until the pH of the mixture is 1 - 3, then raise the temperature to 76.8 - 85 °C and perform distillation to collect the distillate;

[0015] S6 Add anhydrous magnesium sulfate to the obtained distillate for drying to remove the excess water and obtain 3-formyl-2-butenoic acid.

[0016] In some embodiments, the acrylic monomer can be one or a combination of more of n-alkyl acrylate, alkyl acrylate, acrylate, n-alkyl methacrylate, alkyl methacrylate, and methacrylate.

[0017] In some embodiments, the polyaldehyde can be one or a combination of more of glutaraldehyde, malonaldehyde, and succinaldehyde.

[0018] In some embodiments, the polyamine can be one or a combination of more of hexamethylenetetramine, ethylenediamine, hexamethylenediamine, and diphenylmethane diamine.

[0019] In some embodiments, the emulsifier can be one or a combination of more of sodium dodecyl sulfate, 2-acrylamido-methyl-propyl sulfate, and 2-acrylamido-methyl-propyl ammonium sulfate.

[0020] In some embodiments, the initiator can be one or a combination of more of benzoyl peroxide and tert-butyl peroxide.

[0021] In some embodiments, the defoamer can be one or a combination of more of polysiloxane, GP type glycerol polyether, and ethylene glycol siloxane.

[0022] The present invention also provides a preparation method of the above chitin-based acrylic resin, and the preparation method of the chitin-based acrylic resin includes the following steps:

[0023] S4 In a multi-functional reaction kettle, sequentially add chitin modified with acrylic acid, polyaldehyde monomer, emulsifier, defoamer, and deionized water according to the formula weight. While introducing nitrogen, stir at a speed of 200 - 500 r / min for 10 - 20 minutes, react at a temperature of 30 - 40 °C for 0.5 - 1 hour, and then continue to introduce nitrogen for 5 minutes;

[0024] Stop introducing nitrogen gas, add polyamine according to the formula, and react at a temperature of 30 - 40 °C and a stirring speed of 200 - 500 r / min for 0.5 - 1 hour;

[0025] S6 Add acrylic monomer and initiator in sequence according to the formula, heat up to 50 - 60 °C, adjust the stirring speed to 1000 - 2000 r / min, keep warm for 1 - 2 hours, continue to introduce nitrogen gas to take out water vapor and remove free water, then quickly heat up to 100 - 110 °C to initiate the polymerization reaction, and reflux for 2 - 4 hours. The water generated by the reaction is separated by a water separator;

[0026] S7 After the reaction ends, take samples every 30 minutes for acid value testing. When the acid value is 40 - 50 mg KOH / g, stop the reaction, cool down to 40 - 50 °C and keep warm, disperse at a stirring speed of 8000 - 12000 r / min for 30 - 60 minutes, then disperse at a stirring speed of 1000 - 2000 r / min for 30 - 60 minutes, and finally cool down to 30 °C and filter to obtain the chitin-based acrylic resin.

[0027] The present invention has the following advantages:

[0028] (1) Using shrimp shells and crab shells as raw materials, the production cost is relatively low. At the same time, it can reduce the burden on the environment caused by directly discarding shrimp shells and crab shells, which conforms to the production concept of sustainable development;

[0029] (2) The formula does not involve the use of organic solvents, and no gas harmful to human health will be generated during the subsequent use of acrylic resin, which conforms to the production concept of green environmental protection;

[0030] (3) The present invention uses agricultural and forestry waste, namely shrimp shells or crab shells, as raw materials. After deacetylating chitin, chitin with a smaller molecular chain is obtained. At the same time, a large number of highly chemically reactive primary amino groups are exposed on the surface of the chitin molecular chain. Further, 3 - formyl - 2 - butenoic acid (synthesized by hydrolysis of methyl 3 - formyl - 2 - butenoate (CAS: 96928 - 85 - 7)) is used to react with chitin, and acrylic groups are successfully grafted onto the chitin molecular chain. Through polymerization reaction with acrylic monomers, a high - molecular resin is formed. At the same time, cross - reactions with polyaldehydes and polyamines generate network cross - links, improving the strength of the acrylic resin film after film - forming. Brief Description of the Drawings

[0031] Figure 1 Chemical reaction molecular schematic diagram of preparing chitin - based acrylic resin from chitin;

[0032] Figure 2 Scanning electron microscope images of chitosan prepared in Examples 1 - 3;

[0033] Figure 3 Titration curve graphs of chitosan prepared in Examples 1 to 3. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, technical process steps, specific implementation conditions and materials in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Example 1

[0036] The collected shrimp shells and crab shells were washed, dried in the sun, and ground into powder to obtain crude chitin. Then, 100 g of chitin was soaked in 500 mL of hydrochloric acid with a concentration of 5 wt%, and reacted at a temperature of 30 °C and a stirring speed of 500 revolutions per minute for 3 hours. After filtration, it was washed with deionized water until the filtrate was neutral. The filter residue was taken and dried at a temperature of 50 °C. Then, 100 g of the dried chitin powder was soaked in 300 mL of NaOH solution with a concentration of 5 wt%, and reacted at a temperature of 30 °C and a stirring speed of 700 revolutions per minute for 3 hours. After filtration, it was washed with deionized water until the filtrate was neutral. The filter residue was taken and dried at a temperature of 50 °C. Finally, 100 g of the alkali-treated and dried chitin was soaked in a NaClO solution with a concentration of 0.3 wt%, and reacted at a temperature of 30 °C and a stirring speed of 700 revolutions per minute for 3 hours. After filtration, it was washed with deionized water until the filtrate was neutral. The filter residue was taken and dried at a temperature of 50 °C to obtain purified chitin. The purified chitin powder was soaked in 400 mL of NaOH solution with a concentration of 30 wt% for partial deacetylation treatment, and 0.5 g of NaBH 4 , and reacted at 90 °C and a stirring speed of 500 revolutions per minute for 3 hours. After filtration, it was washed with deionized water until the filtrate was neutral. The filter residue was taken, and then acetic acid with a concentration of 1 wt% was dropped to adjust the pH value of the chitin suspension to 3.6, and a deacetylated chitin solution, that is, a chitosan solution, was obtained. The results of scanning electron microscopy characterization are as Figure 2 shown in a. The chitosan has a fibrous structure, with a length distribution of 120 - 480 nm and a width distribution of 18 - 45 nm.

[0037] Example 2

[0038] The collected shrimp shells and crab shells are washed, dried in the sun, and ground into powder to obtain crude chitin. Then, 200 g of chitin is soaked in hydrochloric acid with a concentration of 6 wt% and a volume of 400 mL, and reacted at a temperature of 25 °C and a stirring speed of 400 revolutions per minute for 2 hours. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C. Then, 200 g of the dried chitin powder is soaked in an NaOH solution with a concentration of 8 wt% and a volume of 200 mL, and reacted at a temperature of 25 °C and a stirring speed of 600 revolutions per minute for 2 hours. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C. Finally, 200 g of the alkali-treated and dried chitin is soaked in an NaClO solution with a concentration of 0.6 wt%, and reacted at a temperature of 25 °C and a stirring speed of 600 revolutions per minute for 2 hours. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C to obtain purified chitin. The purified chitin powder is soaked in an NaOH solution with a concentration of 35 wt% and a volume of 300 mL for partial deacetylation treatment, and 1 g of NaBH 4 , and reacted at 85 °C and a stirring speed of 600 revolutions per minute for 2 hours. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken, and then acetic acid with a concentration of 1 wt% is dropped in to adjust the pH value of the chitin suspension to 4.0, that is, the chitosan solution, and the results of scanning electron microscopy characterization are as Figure 2 shown in b. The chitosan has a fibrous structure, with a length distribution of 220 - 680 nm and a width distribution of 20 - 25 nm.

[0039] Example 3

[0040] The collected shrimp and crab shells are washed, dried in the sun, and ground into powder to obtain crude chitin. Then, 300 g of chitin is soaked in 300 mL of hydrochloric acid with a concentration of 8 wt%, and reacted at a temperature of 20 °C and a stirring speed of 200 revolutions per minute for 3 hours. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C. Then, 300 g of the dried chitin powder is soaked in 300 mL of NaOH solution with a concentration of 10 wt%, and reacted at a temperature of 20 °C and a stirring speed of 500 revolutions per minute for 1 hour. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C. Finally, 300 g of the chitin after alkali treatment and drying is soaked in 0.9 wt% NaClO solution, and reacted at a temperature of 20 °C and a stirring speed of 500 revolutions per minute for 1 hour. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken and dried at a temperature of 50 °C to obtain purified chitin. The purified chitin powder is soaked in 200 mL of NaOH solution with a concentration of 30 wt% for partial deacetylation treatment, and 1.5 g of NaBH 4 , and reacted at 90 °C and a stirring speed of 500 revolutions per minute for 1 hour. After filtration, it is washed with deionized water until the filtrate is neutral. The filter residue is taken, and then 1 wt% acetic acid is dropped in to adjust the pH value of the chitin suspension to 3.0, that is, the chitosan solution. The results of scanning electron microscopy characterization are as Figure 2 shown in c. The chitosan has a fibrous structure, with a length of about 360 - 520 nm and a width of about 18 - 22 nm.

[0041] Example 4

[0042] Using an electronic analytical balance, 0.2 g of chitin powder and chitin nanowhisker samples dried to constant weight at 105 °C are accurately weighed in a beaker respectively, and then standard solutions of 0.1 mol / L HCl and 0.1 mol / L NaOH are prepared respectively. At 25 °C, first add 20 mL of HCl solution to the beaker and stir magnetically for 30 min to dissolve the sample. Subsequently, add 30 mL of deionized water. Insert the pH glass electrode on the Eco potentiometric titrator into the solution to be measured, and at the same time titrate with the prepared 0.1 mol / L NaOH solution. The instrument automatically records the change in the pH value of the solution during the titration process and the volume of the consumed NaOH standard solution. Plot the pH value against the titration volume of the NaOH standard solution, and the pH-V NaOH titration curve can be obtained. Make the first derivative curve of the pH value against V NaOH , and the ΔpH-ΔV NaOH double jump titration curve can be obtained. According to the definition of the degree of deacetylation, calculate the degree of deacetylation according to the following formula:

[0043]

[0044] Among them, m 干重 is the mass of deacetylated chitin; V 1 and V 2 respectively represent the volumes consumed by 0.1 mol / L NaOH at two inflection points; c represents the concentration of NaOH; the degree of deacetylation and the amino group content w NH2 are based on percentages, and each sample is tested three times repeatedly and the average value is taken. The test results are as Figure 3 shown. The degrees of deacetylation of Examples 1, 2, and 3 are 38.9%, 42.6%, and 46.7% respectively. The results show that after the deacetylation treatment, a large number of primary amino groups are exposed in the chitin molecular chain.

[0045] Example 5

[0046] Methyl 3-formyl-2-butenoate was added to a multi-functional reaction kettle, and sodium hydroxide was added to adjust the pH to 12.7. At a stirring speed of 300 revolutions per minute and a temperature of 40 °C, the reaction was carried out for 4 hours. The reaction solution was added with hydrochloric acid until the pH of the mixture was 2, and then the temperature was raised to 79.4 °C for distillation, and the distillate was collected; the obtained distillate was added with anhydrous magnesium sulfate for drying to remove the excess water, and 3-formyl-2-butenoic acid was obtained.

[0047] Example 6

[0048] By mass, 10 parts of a chitin solution, 10 parts of 3-formyl-2-butenoic acid, and 2 parts of hydrochloric acid were successively added to a multi-functional reaction kettle. At a stirring speed of 500 revolutions per minute, the reactants were reacted at 40 °C for 3 hours, and then NaHCO 3 solution was added to neutralize the acid in the filter residue, the reaction was stopped, filtered, washed 3 times with methanol, and then washed with deionized water until the filtrate was neutral. The filter residue was taken and vacuum dried at 40 °C to obtain acrylic acid-modified chitin.

[0049] Example 7

[0050] By mass, 20 parts of a chitin solution, 15 parts of 3-formyl-2-butenoic acid, and 3 parts of hydrochloric acid were successively added to a multi-functional reaction kettle. At a stirring speed of 800 revolutions per minute, the reactants were reacted at 35 °C for 2 hours, and then NaHCO 3 solution was added to neutralize the acid in the filter residue, the reaction was stopped, filtered, washed 3 times with methanol, and then washed with deionized water until the filtrate was neutral. The filter residue was taken and vacuum dried at 35 °C to obtain acrylic acid-modified chitin.

[0051] Example 8

[0052] By mass parts, 30 parts of chitin solution, 20 parts of 3-formyl-2-butenoic acid, and 5 parts of hydrochloric acid were successively added to a multi-functional reaction kettle. While stirring at a speed of 500 revolutions per minute, the reactants were reacted at 30 °C for 1 hour, and then NaHCO 3 solution was added to neutralize the acid in the filter residue, the reaction was stopped, filtered, washed 3 times with methanol, and then washed with deionized water until the filtrate was neutral. The filter residue was taken and vacuum dried at 40 °C to obtain acrylic acid-modified chitin.

[0053] Example 9

[0054] In a multi-functional reaction kettle, according to the formula weight, acrylic acid-modified chitin, glutaraldehyde, sodium dodecyl sulfate, polysiloxane, and deionized water were successively added. While introducing nitrogen, stirring was carried out at a speed of 200 r / min for 20 minutes, and the reaction was carried out at a temperature of 30 °C for 1 hour, and then nitrogen was continuously introduced for 5 minutes; the introduction of nitrogen was stopped, and hexamethylenetetramine was added according to the formula amount, and the reaction was carried out at a temperature of 30 °C and a stirring speed of 200 r / min for 1 hour; according to the formula amount, n-alkyl acrylate and benzoyl peroxide were successively added, heated to 50 °C, the stirring speed was adjusted to 1000 r / min, kept warm for 2 hours, and nitrogen was continuously introduced to carry out the water vapor, remove the free water, and then quickly heated to 100 °C to initiate the polymerization reaction, and the reflux reaction was carried out for 4 hours. The water generated by the reaction was separated by a water separator; after the reaction was completed, a sample was taken every 30 minutes for acid value testing. When the acid value was 40-50 mg KOH / g, the reaction was stopped, cooled to 40 °C and kept warm, dispersed at a stirring speed of 8000 r / min for 60 minutes, and then dispersed at a stirring speed of 1000 r / min for 60 minutes. Finally, it was cooled to 30 °C, filtered, and the chitin-based acrylic resin was obtained.

[0055] Table 1 Raw material ratio of chitin-based acrylic resin in Example 9

[0056] Acrylic-modified chitin 30 parts n-alkyl acrylate 20 parts Glutaraldehyde 10 parts Hexamethylenetetramine 5 parts Sodium dodecyl sulfate 1 part Benzoyl peroxide 0.1 part Polysiloxane 0.2 part Deionized water 80 parts

[0057] The acrylic acid-based modified chitin used in this example was the acrylic acid-based modified chitin prepared in Example 5.

[0058] According to GB / T 6739-1996 "Pencil Test Method for Film Hardness", the strength of the prepared chitin-based acrylic resin film (cured at 50 °C for 3 hours) was tested by the manual method, and the test results showed that the film strength > B.

[0059] According to GB / T 23985-2009 "Determination of Volatile Organic Compounds (VOC) Content in Paints and Varnishes - Difference Method", the VOC of the prepared resin film was tested, and the result was VOC ≤ 36.3.

[0060] The water resistance of the prepared resin film was tested according to GB / T 1727-1992. After soaking for 48 hours, the water absorption rate was 11.8%.

[0061] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 123.48 kPa.

[0062] Example 10

[0063] In a multi-functional reaction kettle, according to the formula weight, acrylic acid-modified chitin, malondialdehyde, 2-acrylamido-methyl-propyl sodium sulfate, GP-type glycerol polyether, and deionized water were added in sequence. While introducing nitrogen, stirring was carried out at a speed of 300 r / min for 15 minutes, and the reaction was carried out at a temperature of 35 °C for 1 hour, and then nitrogen was introduced continuously for 5 minutes; the introduction of nitrogen was stopped, and ethylenediamine was added according to the formula amount, and the reaction was carried out at a temperature of 35 °C and a stirring speed of 300 r / min for 1 hour; according to the formula amount, acrylic alkyl ester and tert-butyl peroxide were added in sequence, the temperature was heated up to 55 °C, the stirring speed was adjusted to 1500 r / min, and it was kept warm for 1.5 hours, and nitrogen was introduced continuously to carry out the water vapor, remove the free water, and then quickly raise the temperature to 105 °C to initiate the polymerization reaction, and the reflux reaction was carried out for 3 hours, and the water generated by the reaction was separated by a water separator; after the reaction was completed, samples were taken every 30 minutes for acid value testing. When the acid value was 40-50 mg KOH / g, the reaction was stopped, the temperature was lowered to 45 °C and kept warm, dispersed at a stirring speed of 10000 r / min for 45 minutes, and then dispersed at a stirring speed of 1500 r / min for 45 minutes, and finally the temperature was lowered to 30 °C, and filtered to obtain the chitin-based acrylic resin.

[0064] Table 2 Raw material ratio of chitin-based acrylic resin in Example 10

[0065] Acrylic-modified chitin 40 parts Alkyl acrylate 25 parts Malonaldehyde 15 parts Ethylenediamine 7 parts 2-Acrylamido-2-methylpropanesulfonic acid sodium salt 3 parts tert-Butyl hydroperoxide 0.3 part GP-type glycerol polyether 0.3 part Deionized water 100 parts

[0066] The acrylic acid-based modified chitin used in this example was the acrylic acid-based modified chitin prepared in Example 6.

[0067] According to GB / T 6739-1996 "Pencil Test Method for Film Hardness", the strength of the prepared chitin-based acrylic resin film (cured at 50 °C for 3 hours) was tested by the manual method, and the test results showed that the film strength > B.

[0068] The VOC of the prepared resin film was tested according to GB / T 23985-2009 "Determination of Volatile Organic Compounds (VOC) Content in Paints and Varnishes - Difference Method", and the result was VOC ≤ 42.7.

[0069] The water resistance of the prepared resin film was tested according to GB / T 1727-1992. After soaking for 48 hours, the water absorption rate was 9.89%.

[0070] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 142.89 kPa.

[0071] Example 11

[0072] In a multi-functional reaction kettle, according to the formula weight, acrylic acid-modified chitin, succinaldehyde, 2-acrylamido-methyl-propyl ammonium sulfate, ethylene glycol siloxane, and deionized water were added in sequence. While introducing nitrogen, stirring was carried out at a speed of 500 r / min for 10 minutes, and the reaction was carried out at a temperature of 40 °C for 0.5 hour, and then nitrogen was introduced continuously for 5 minutes; nitrogen introduction was stopped, and diphenylmethane diamine was added according to the formula amount, and the reaction was carried out at a temperature of 40 °C and a stirring speed of 500 r / min for 0.5 hour; according to the formula amount, methacrylate and benzoyl peroxide were added in sequence, the temperature was raised to 60 °C, the stirring speed was adjusted to 2000 r / min, and it was kept warm for 1 hour, and nitrogen was introduced continuously to carry out the water vapor out and remove the free water, and then the temperature was quickly raised to 110 °C to initiate the polymerization reaction, and the reflux reaction was carried out for 2 hours, and the water generated by the reaction was separated by a water separator; after the reaction was completed, samples were taken every 30 minutes for acid value testing. When the acid value was 40-50 mg KOH / g, the reaction was stopped, the temperature was lowered to 40-50 °C and kept warm, and it was dispersed at a stirring speed of 12000 r / min for 30 minutes, and then dispersed at a stirring speed of 2000 r / min for 30 minutes. Finally, the temperature was lowered to 30 °C and filtered to obtain the chitin-based acrylic resin.

[0073] Table 3 Raw material ratio of chitin-based acrylic resin in Example 11

[0074] Acrylic-modified chitin 50 parts Methacrylate 30 parts Succinaldehyde 20 parts Diphenylmethane diamine 10 parts 2-Acrylamido-2-methylpropanesulfonic acid ammonium salt 5 parts Benzoyl peroxide 0.5 part Ethylene glycol siloxane 0.4 part Deionized water 120 parts

[0075] The acrylic acid-based modified chitin used in this example was the acrylic acid-based modified chitin prepared in Example 7.

[0076] According to GB / T 6739-1996 "Pencil Test Method for Film Hardness", the strength of the prepared chitin-based acrylic resin film (cured at 50 °C for 3 hours) was tested by the manual method, and the test results showed that the film strength > B.

[0077] The VOC of the prepared resin film was tested according to GB / T 23985-2009 "Determination of Volatile Organic Compounds (VOC) Content in Paints and Varnishes - Difference Method", and the result was VOC ≤ 50.9.

[0078] The water resistance of the prepared resin film was tested according to GB / T 1727-1992. After soaking for 48 hours, the water absorption rate was 8.76%.

[0079] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 123.48 kPa.

[0080] Example 12

[0081] The process parameters were the same as those in Example 8. The formulation was the same except that glutaraldehyde and hexamethylenetetramine in Example 9 were not added.

[0082] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 79.68 kPa.

[0083] Example 13

[0084] The process parameters were the same as those in Example 10. The formulation was the same except that malondialdehyde and ethylenediamine in Example 9 were not added.

[0085] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 89.71 kPa.

[0086] Example 14

[0087] The process parameters were the same as those in Example 11. The formulation was the same except that succinaldehyde and diphenylmethane diamine in Example 10 were not added.

[0088] The tensile strength of the formed resin film (cured at 50 °C for 3 hours) was tested with a universal tensile testing machine, and the film strength was 72.56 kPa.

[0089] By comparing the film strengths of Example 9 and Example 12, Example 10 and Example 13, and Example 11 and Example 14, it can be seen that the introduction of polyaldehyde and organic polyamine can promote the formation of a network crosslink between chitin molecules and improve the film strength.

[0090] All technicians should note that although the present invention has been described according to the above specific embodiments, the inventive concept of the present invention is not limited to this invention only. Any modification using the inventive concept of the present invention will be included in the scope of protection of the patent right of this patent.

Claims

1. A chitin-based acrylic resin, characterized in that The chitin-based acrylic resin is composed of 30-50 parts of acrylic acid-modified chitin, 20-30 parts of acrylic acid monomer, 10-20 parts of polyaldehyde monomer, 5-10 parts of polyorganic amine, 1-5 parts of emulsifier, 0.1-0.5 parts of initiator, 0.2-0.4 parts of defoamer and 80-120 parts of deionized water by weight. The preparation method of acrylic acid-modified chitin comprises the following steps: S1 pretreatment: The collected shrimp shells and crab shells are washed, dried, and ground into powder to obtain crude chitosan, and then 100-300g of chitosan is soaked in a hydrochloric acid solution with a concentration of 5-8wt% and a volume of 300-500mL, and reacted for 1-3 hours at a temperature of 20-30°C and a stirring speed of 200-500 rpm, filtered, and washed with deionized water until the filtrate is neutral, and the filter residue is taken and dried at a temperature of 50°C; then, 100-300g of the dried chitosan powder is soaked in a NaOH solution with a concentration of 5-10wt% and a volume of 100-300mL. The chitosan was treated with alkali and dried for 1 to 3 hours at a temperature of 20 to 30° C. and a stirring speed of 500 to 700 rpm, and then the chitosan was filtered, washed with deionized water until the filtrate was neutral, and the residue was dried at a temperature of 50° C.; finally, 100 to 300 g of the chitosan treated with alkali and dried was immersed in a NaClO solution having a concentration of 0.3 to 0.9 wt %, and then the chitosan was reacted for 1 to 3 hours at a temperature of 20 to 30° C. and a stirring speed of 500 to 700 rpm, and then the chitosan was filtered, washed with deionized water until the filtrate was neutral, and the residue was dried at a temperature of 50° C. to obtain purified chitosan; S2 deacetylation: the purified chitosan powder is immersed in a NaOH solution with a concentration of 30-40wt% and a volume of 200-400mL for partial deacetylation, and 0.5-1.5g of NaBH4 is added, and the mixture is reacted at 80-90°C and a stirring speed of 500-700 rpm for 1-3 hours, filtered, and washed with deionized water until the filtrate is neutral, the filter residue is taken, and then acetic acid with a concentration of 1wt% is dripped into the chitosan suspension to adjust the pH value to 3.0-4.0, thereby obtaining a deacetylated chitosan solution, i.e., a chitin solution, which is stored in a 4°C environment for standby use; S3 Acrylic acid modification of chitin: 10-30 parts of chitin solution, 10-20 parts of 3-formyl-2-butenoic acid and 2-5 parts of hydrochloric acid are added to a multifunctional reactor in sequence according to their mass proportions. The reactants are reacted at 30-40°C for 1-3 hours under a stirring speed of 500-1000 rpm. Then, NaHCO3 solution is added to neutralize the acid in the filter residue. The reaction is stopped, filtered, washed with methanol 3 times, and then washed with deionized water until the filtrate is neutral. The filter residue is taken and vacuum dried at 30-40°C to obtain acrylic acid-modified chitin.

2. The chitin-based acrylic resin according to claim 1, characterized in that The preparation method of 3-aldehyde-2-butenoic acid described in S3 comprises the following steps: S4: adding 3-formyl-2-butenoic acid methyl ester to a multifunctional reaction kettle, adding sodium hydroxide to adjust the pH to 11.6-13.8, and reacting for 2-6 hours at a stirring speed of 200-500 rpm and a temperature of 30-50° C.; S5: adding hydrochloric acid to the solution after the reaction in S4 until the pH of the mixed solution is 1 to 3, then heating to 76.8 to 85° C., distilling, and collecting fractions; S6: adding anhydrous magnesium sulfate to the obtained fraction for drying, removing excess water, and obtaining 3-formyl-2-butenoic acid.

3. The chitin-based acrylic resin according to claim 1, wherein The acrylic monomer may be a combination of one or more of n-alkyl acrylate, alkyl acrylate, acrylate, n-alkyl methacrylate, alkyl methacrylate, and methacrylate.

4. The chitin-based acrylic resin according to claim 1, characterized in that The polyaldehyde may be a combination of one or more of glutaraldehyde, malondialdehyde and succindialdehyde.

5. The chitin-based acrylic resin according to claim 1, characterized in that The polyvalent organic amine may be a combination of one or more of hexamethylenetetramine, ethylenediamine, hexamethylenediamine, and diphenylmethanediamine.

6. The chitin-based acrylic resin according to claim 1, characterized in that The emulsifier may be a combination of one or more of sodium dodecylsulfate, sodium 2-acrylamido-methyl-propyl sulfate, and ammonium 2-acrylamido-methyl-propyl sulfate.

7. The chitin-based acrylic resin according to claim 1, characterized in that The initiator can be a combination of benzoyl peroxide and tert-butyl peroxide.

8. The chitin-based acrylic resin according to claim 1, characterized in that The defoaming agent can be a combination of one or more of polysiloxane, GP type glycerol polyether, and ethylene glycol siloxane.

9. The method for preparing a chitin-based acrylic resin according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: S7: In a multifunctional reactor, acrylic acid-modified chitin, polyaldehyde monomer, emulsifier, defoamer, and deionized water are added in sequence according to the formula weight, and nitrogen is introduced while stirring at a speed of 200 to 500 r / min for 10 to 20 minutes, reacting at a temperature of 30 to 40° C. for 0.5 to 1 hour, and then nitrogen is continued to be introduced for 5 minutes; S8: Stop introducing nitrogen, add polyvalent organic amine according to the formula, and react for 0.5 to 1 hour at a temperature of 30 to 40°C and a stirring speed of 200 to 500 r / min; S9: according to the formula, add acrylic acid monomer and initiator in sequence, heat to 50-60°C, adjust the stirring speed to 1000-2000r / min, keep warm for 1-2 hours, continue to introduce nitrogen to take out water vapor and remove free water, then quickly heat to 100-110°C to initiate polymerization, reflux reaction for 2-4 hours, and separate the water produced by the reaction with a water separator; S10 After the reaction is completed, samples are taken every 30 minutes for acid value testing. When the acid value is 40-50 mg KOH / g, the reaction is stopped, the temperature is lowered to 40-50° C. and kept warm, and the mixture is dispersed for 30-60 minutes at a stirring speed of 8000-12000 r / min, and then dispersed for 30-60 minutes at a stirring speed of 1000-2000 r / min, and finally the temperature is lowered to 30° C. and filtered to obtain the chitin-based acrylic resin.

Images