A bio-based fluorine-free oil repellent and a preparation process thereof

Abstract

The application discloses a kind of bio-based fluorine-free oil-proof agent and its preparation process, it is related to oil-proof agent technical field.Cystose is a kind of natural polysaccharide, with good biodegradability and certain waterproof and oil-proof performance.The application forms stable composite system through the crosslinking effect of cystose and sodium alginate, improves the oil-proof effect of oil-proof agent by the filling effect of cellulose nanocrystal-corn alcohol soluble protein complex.Oil-proof agent changes the hydrophobicity of paper surface, so that oil droplets are not easy to adhere or penetrate.The application also adds brazilian palm wax emulsion in oil-proof agent, which provides excellent hydrophobicity and ensures more durable oil-proof effect.The application composites corn alcohol soluble protein with cellulose nanocrystal to prepare cellulose nanocrystal-soy protein complex, improves the hydrophobicity of cellulose nanocrystal, so that oil droplets are not easy to adhere or penetrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil repellent agents, and particularly relates to a bio-based fluorine-free oil repellent agent and a preparation process thereof. BACKGROUND

[0002] With the improvement of environmental awareness of consumers, more and more people tend to choose environmentally friendly oil-proof paper as the packaging of molded meal boxes and electronic products. The application of oil repellent agents in the field of paper packaging is to improve the penetration of paper-based materials into the interior of the paper when contacting liquid, to avoid leakage and pollution. The oil repellent agent can change the hydrophobicity of the surface of the paper, so that oil droplets are not easy to adhere or penetrate.

[0003] Fluorine-containing compounds have been widely used in paper packaging due to their excellent oil-repellent performance. However, the use of such compounds has been strictly limited because they are difficult to degrade and harmful to human health. Therefore, it is crucial to develop a fluorine-free oil repellent agent in the current market.

[0004] In order to solve the above problems and improve the hydrophobicity of the oil repellent agent, the present application provides a bio-based fluorine-free oil repellent agent and a preparation process thereof. SUMMARY

[0005] The present application aims to provide a bio-based fluorine-free oil repellent agent and a preparation process thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A preparation process of a bio-based fluorine-free oil repellent agent, comprising the following steps:

[0008] Step 1: Take polyhydroxyalkanoate and dichloromethane, stir until uniform, add cellulose nanocrystal-corn zein compound, stir for 1-2 h, add chitosan, stir for 2-3 h, and obtain oil-proof cellulose nanocrystal;

[0009] Step 2: Add chitosan powder to acetic acid solution and stir until completely dissolved to form a chitosan solution; dissolve sodium alginate in deionized water and stir until uniform to obtain a sodium alginate solution;

[0010] Step 3: Add the oil-proof cellulose nanocrystal to the chitosan solution and stir until uniform, add the sodium alginate solution and stir until uniform, add calcium alginate, emulsifier and glycerol, and stir until uniform to obtain a bio-based fluorine-free oil repellent agent.

[0011] More preferably, the bio-based fluorine-free oil-proof agent comprises the following ingredients by weight: 2-3 parts of chitosan solution, 2-3 parts of sodium alginate solution, 0.1-0.2 parts of calcium alginate, 0.2-0.4 parts of oil-proof cellulose nanocrystal, 1-2 parts of emulsifier, 1-2 parts of glycerol, 2-3 parts of carnauba wax emulsion.

[0012] More preferably, the preparation method of the cellulose nanocrystal-zein complex is as follows: taking zein and deionized water, heating to 70-75 DEG C, stirring for 50-70 min to obtain a zein solution; adding cellulose nanocrystal and silane coupling agent 570 to the zein solution, stirring at 60-65 DEG C for 50-70 min to obtain the cellulose nanocrystal-zein complex.

[0013] More preferably, the mass ratio of the zein, cellulose nanocrystal, silane coupling agent 570 and deionized water is (2.3-2.8):(0.4-0.6):(2-2.5):100.

[0014] More preferably, the emulsifier is Tween 80.

[0015] More preferably, in step one, the mass ratio of the polyhydroxyalkanoate, cellulose nanocrystal-zein complex and chitosan is (0.5-0.7):(1.7-2.2):(0.1-0.2).

[0016] More preferably, the preparation method of the cellulose nanocrystal is as follows: taking bran, crushing, sieving, washing and drying to obtain bran powder; taking the bran powder and sodium hydroxide solution, stirring at 90 DEG C for 1-3 h, filtering, washing and drying to obtain treated bran powder; taking the treated bran powder, adding to deionized water, resuspending for 1-1.5 h, then adding alpha-amylase, stirring at 25-30 DEG C for 3-4 h, adjusting pH to 11, adding papain, and stirring at 75-80 DEG C for 1 h, centrifuging, washing and drying to obtain a precipitate; taking sodium hypochlorite, glacial acetic acid, sodium hydroxide and deionized water, stirring uniformly to obtain a bleaching solution; taking the precipitate and the bleaching solution, stirring at 75-80 DEG C for 1.5-2.5 h, filtering, washing and drying to obtain bran fiber; taking the bran fiber and sulfuric acid solution, stirring uniformly, hydrolyzing, centrifuging, dialyzing, ultrasonic dispersing for 30-40 min, filtering and drying to obtain cellulose nanocrystal.

[0017] More preferably, the power of the ultrasonic dispersion is 150W-200W.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1、Chitosan is a kind of natural polysaccharide, which has good biodegradability and certain waterproof and oil-proof performance. The application forms a stable composite system through the cross-linking effect of chitosan and sodium alginate, and improves the oil-proof effect of the oil-proof agent by combining the filling effect of cellulose nanocrystal-corn protein composite. The oil-proof agent changes the hydrophobicity of the paper surface, so that oil droplets are not easy to adhere or penetrate. The application also adds carnauba wax emulsion to the oil-proof agent, which provides excellent hydrophobicity and ensures more durable oil-proof effect.

[0020] 2、The application prepares cellulose nanocrystal-soy protein composite by compounding corn protein with cellulose nanocrystal. Corn protein has good biocompatibility, degradability and oil-proof performance. Compounding corn protein with cellulose nanocrystal can improve the hydrophobicity of cellulose nanocrystal, so that oil droplets are not easy to adhere or penetrate.

[0021] 3、The cellulose nanocrystal-soy protein composite is modified by using polyhydroxyalkanoate. The addition of polyhydroxyalkanoate improves the oil-proof effect of the oil-proof agent, but polyhydroxyalkanoate has poor water solubility. Compounding polyhydroxyalkanoate with cellulose nanocrystal-soy protein composite can improve the stability of polyhydroxyalkanoate, thereby improving the performance of the oil-proof agent. Chitosan is also added. The addition of chitosan improves the compatibility in the bio-based fluorine-free oil-proof agent matrix, improves the dispersibility of the oil-proof cellulose nanocrystal, improves the strength of the oil-proof paper, and further improves the hydrophobicity of the oil-proof agent. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0023] The sources of the substances involved in the application are not specially limited, and exemplarily include: pulp: item number 555, which can be purchased from Henan Huining Paper Co., Ltd.; carnauba wax emulsion: type: BX25, which can be purchased from Shanghai Jol Wax Co., Ltd.; corn protein: type: Z3625, which can be purchased from Merck.

[0024] Embodiment 1: A preparation process of a bio-based fluorine-free oil-proof agent, comprising the following steps:

[0025] Step one: 1g of chitosan powder is added to 50mL of acetic acid solution, and stirred until completely dissolved to form a chitosan solution; 1g of sodium alginate is dissolved in 50mL of water, and stirred uniformly to obtain a sodium alginate solution;

[0026] Step two: add the oil-proof cellulose nanocrystals into the chitosan solution, stir evenly, add the sodium alginate solution, stir evenly, add the calcium alginate, emulsifier Tween 80 and glycerol, carnauba wax emulsion, stir evenly, to obtain the bio-based fluorine-free oil-proof agent;

[0027] The bio-based fluorine-free oil-proof agent comprises the following ingredients by weight: 2.5 parts of chitosan solution, 2.5 parts of sodium alginate solution, 0.15 parts of calcium alginate, 0.3 parts of oil-proof cellulose nanocrystals, 1.5 parts of emulsifier Tween 80, 1.5 parts of glycerol, and 2.5 parts of carnauba wax emulsion;

[0028] The preparation process of the oil-proof cellulose nanocrystals comprises the following steps:

[0029] S1: Preparation of cellulose nanocrystals:

[0030] Take the rice chaff, crush, and pass through an 80-mesh sieve, wash and dry; take 100 g of rice chaff powder and 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 2 h, filter, wash and dry to obtain treated rice chaff powder; take 10 g of the treated rice chaff powder and add it to 2000 mL of 80°C deionized water, resuspend for 1.3 h, then add 0.1 g of α-amylase (4000 U / g), stir at 28°C for 3.5 h, adjust the pH to 11, add 1 g of papain, and stir at 78°C for 1 h, centrifuge, wash and dry to obtain a precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide and 100 mL of deionized water, stir evenly to obtain a bleaching solution; take 4 g of the precipitate and 100 mL of the bleaching solution, stir at 78°C for 2 h, filter, wash and dry to obtain rice chaff fibers; take 4 g of the rice chaff fibers and 60 mL of 62% sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialyze, ultrasonic dispersion at 150 W ultrasonic power for 35 min, filter and dry to obtain cellulose nanocrystals;

[0031] S2: Preparation of cellulose nanocrystal-corn protein complex:

[0032] Take 2.5 g of corn protein and 100 mL of deionized water, heat to 72°C and stir for 60 min to obtain a corn protein solution; add 0.5 g of cellulose nanocrystals and 2.2 g of silane coupling agent 570 to the corn protein solution, stir at 62°C for 60 min to obtain a cellulose nanocrystal-corn protein complex;

[0033] S3: Preparation of oil-proof cellulose nanocrystals:

[0034] Take 0.6g polyhydroxyalkanoate, 30mL dichloromethane, stir evenly, add 2g cellulose nanocrystal-corn protein complex, stir for 1.5h, add 0.15g chitosan, stir for 2.5h, get oil-proof cellulose nanocrystal;

[0035] Step three: preparation of oil-proof paper:

[0036] Add 7kg bio-based fluorine-free oil-proof agent to 100kg paper pulp, stir evenly, shape, squeeze, dry, get oil-proof paper with thickness of 0.01mm.

[0037] Example 2: a preparation process of a bio-based fluorine-free oil-proof agent, including the following steps:

[0038] Step one: add 1g chitosan powder to 50mL acetic acid solution, stir until completely dissolved, form chitosan solution; dissolve 1g sodium alginate in 50mL water, stir evenly, get sodium alginate solution;

[0039] Step two: add oil-proof cellulose nanocrystal to chitosan solution, stir evenly, add sodium alginate solution, stir evenly, add calcium alginate, emulsifier Tween 80 and glycerol, carnauba wax emulsion, stir evenly, get bio-based fluorine-free oil-proof agent;

[0040] The bio-based fluorine-free oil-proof agent includes the following ingredients, by weight: 2 parts chitosan solution, 2 parts sodium alginate solution, 0.1 parts calcium alginate, 0.2 parts oil-proof cellulose nanocrystal, 1 part emulsifier Tween 80, 1 part glycerol, 2 parts carnauba wax emulsion;

[0041] The preparation process of the oil-proof cellulose nanocrystal is, including the following steps:

[0042] S1: preparation of cellulose nanocrystal:

[0043] Take the bran, crush, pass through 80 mesh screen, wash, dry; take 100 g of bran powder, 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 1 h, filter, wash, dry, get treated bran powder, take 10 g of treated bran powder, add to 2000 mL of 80°C deionized water, resuspend for 1 h, then add 0.1 g of α-amylase (4000 U / g), stir at 25°C for 3 h, adjust pH to 11, add 1 g of papain, and stir at 75°C for 1 h, centrifuge, wash, dry, get the precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide, 100 mL of deionized water, stir evenly to get bleaching solution; take 4 g of precipitate, 100 mL of bleaching solution, stir at 75°C for 1.5 h, filter, wash, dry, get bran fiber; take 4 g of bran fiber, 60 mL of 62% sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialysis, ultrasonic dispersion at 150 W ultrasonic power for 30 min, filter, dry, get cellulose nanocrystals;

[0044] S2: Preparation of cellulose nanocrystal-zipper protein complex:

[0045] Take 2.5 g of corn protein, 100 mL of deionized water, heat to 70°C, stir for 50 min to get corn protein solution; add 0.5 g of cellulose nanocrystals, 2.2 g of silane coupling agent 570 to the corn protein solution, stir at 60°C for 50 min to get cellulose nanocrystal-corn protein complex;

[0046] S3: Preparation of oil-proof cellulose nanocrystals:

[0047] Take 0.6 g of polyhydroxyalkanoate, 30 mL of dichloromethane, stir evenly, add 2 g of cellulose nanocrystal-corn protein complex, stir for 1 h, add 0.15 g of chitosan, stir for 2 h to get oil-proof cellulose nanocrystals;

[0048] Step three: preparation of oil-proof paper:

[0049] Add 7 kg of bio-based fluorine-free oil-proof agent to 100 kg of paper pulp, stir evenly, shape, press, dry to get oil-proof paper with a thickness of 0.01 mm.

[0050] Example 3: a preparation process of a bio-based fluorine-free oil-proof agent, including the following steps:

[0051] Step one: add 1 g of chitosan powder to 50 mL of acetic acid solution, stir until completely dissolved to form a chitosan solution; dissolve 1 g of sodium alginate in 50 mL of water, stir evenly to get a sodium alginate solution;

[0052] Step two: add the oil-proof cellulose nanocrystals into the chitosan solution, stir evenly, add the sodium alginate solution, stir evenly, add the calcium alginate, emulsifier Tween 80 and glycerol, carnauba wax emulsion, stir evenly, to obtain the bio-based fluorine-free oil-proof agent;

[0053] The bio-based fluorine-free oil-proof agent comprises the following ingredients by weight: 3 parts of chitosan solution, 3 parts of sodium alginate solution, 0.2 parts of calcium alginate, 0.4 parts of oil-proof cellulose nanocrystals, 2 parts of emulsifier Tween 80, 2 parts of glycerol, and 3 parts of carnauba wax emulsion;

[0054] The preparation process of the oil-proof cellulose nanocrystals comprises the following steps:

[0055] S1: Preparation of cellulose nanocrystals:

[0056] Take the rice chaff, crush, and pass through an 80-mesh sieve, wash and dry; take 100 g of rice chaff powder and 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 3 h, filter, wash and dry to obtain treated rice chaff powder; take 10 g of the treated rice chaff powder and add it to 2000 mL of 80°C deionized water, resuspend for 1.5 h, then add 0.1 g of α-amylase (4000 U / g), stir at 30°C for 4 h, adjust the pH to 11, add 1 g of papain, and stir at 80°C for 1 h, centrifuge, wash and dry to obtain a precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide and 100 mL of deionized water, stir evenly to obtain a bleaching solution; take 4 g of the precipitate and 100 mL of the bleaching solution, stir at 80°C for 2.5 h, filter, wash and dry to obtain rice chaff fibers; take 4 g of the rice chaff fibers and 60 mL of 62% sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialyze, ultrasonic dispersion at 150 W ultrasonic power for 40 min, filter and dry to obtain cellulose nanocrystals;

[0057] S2: Preparation of cellulose nanocrystal-corn protein complex:

[0058] Take 2.5 g of corn protein and 100 mL of deionized water, heat to 75°C and stir for 70 min to obtain a corn protein solution; add 0.5 g of cellulose nanocrystals and 2.2 g of silane coupling agent 570 to the corn protein solution, stir at 65°C for 70 min to obtain a cellulose nanocrystal-corn protein complex;

[0059] S3: Preparation of oil-proof cellulose nanocrystals:

[0060] Take 0.6 g of polyhydroxyalkanoate, 30 mL of dichloromethane, stir evenly, add 2 g of cellulose nanocrystal-corn protein complex, stir for 2 h, add 0.15 g of chitosan, stir for 3 h, and obtain oil-proof cellulose nanocrystal;

[0061] Step three: preparation of oil-proof paper:

[0062] Add 7 kg of bio-based fluorine-free oil-proof agent to 100 kg of paper pulp, stir evenly, shape, press, and dry to obtain oil-proof paper with a thickness of 0.01 mm.

[0063] Comparative example 1: no corn protein is added, and the rest is the same as example 1:

[0064] Step one: add 1 g of chitosan powder to 50 mL of acetic acid solution and stir until completely dissolved to form a chitosan solution; dissolve 1 g of sodium alginate in 50 mL of water and stir evenly to obtain a sodium alginate solution;

[0065] Step two: add the oil-proof cellulose nanocrystal to the chitosan solution, stir evenly, add the sodium alginate solution, stir evenly, add calcium alginate, emulsifier Tween 80, and glycerol, and stir evenly to obtain a bio-based fluorine-free oil-proof agent;

[0066] The bio-based fluorine-free oil-proof agent includes the following ingredients by weight: 2.5 parts of chitosan solution, 2.5 parts of sodium alginate solution, 0.15 parts of calcium alginate, 0.3 parts of oil-proof cellulose nanocrystal, 1.5 parts of emulsifier Tween 80, 1.5 parts of glycerol, and 2.5 parts of carnauba wax emulsion;

[0067] The preparation process of the oil-proof cellulose nanocrystal includes the following steps:

[0068] S1: preparation of cellulose nanocrystal:

[0069] Take the bran, crush, pass through 80 mesh screen, wash, dry; take 100 g of bran powder, 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 2 h, filter, wash, dry, get treated bran powder, take 10 g of treated bran powder, add to 2000 mL of 80°C deionized water, resuspend for 1.3 h, then add 0.1 g of α-amylase (4000 U / g), stir at 28°C for 3.5 h, adjust pH to 11, add 1 g of papain, and stir at 78°C for 1 h, centrifuge, wash, dry, get the precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide, 100 mL of deionized water, stir evenly to get bleaching solution; take 4 g of precipitate, 100 mL of bleaching solution, stir at 78°C for 2 h, filter, wash, dry, get bran fiber; take 4 g of bran fiber, 60 mL of 62% sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialysis, ultrasonic dispersion at 150 W ultrasonic power for 35 min, filter, dry, get cellulose nanocrystals;

[0070] S2: Preparation of oil-proof cellulose nanocrystals:

[0071] Take 0.6 g of polyhydroxyalkanoate, 30 mL of dichloromethane, stir evenly, add 2 g of cellulose nanocrystals, stir for 1.5 h, add 0.15 g of chitosan, stir for 2.5 h, get oil-proof cellulose nanocrystals;

[0072] Step three: Preparation of oil-proof paper:

[0073] Add 7 kg of bio-based fluorine-free oil-proof agent to 100 kg of paper pulp, stir evenly, shape, press, dry, get oil-proof paper with thickness of 0.01 mm.

[0074] Comparative example 2: without using polyhydroxyalkanoate to modify cellulose nanocrystal-soy protein composite, the rest is the same as example 1:

[0075] Step one: add 1 g of chitosan powder to 50 mL of acetic acid solution, stir until completely dissolved to form a chitosan solution; dissolve 1 g of sodium alginate in 50 mL of water, stir evenly to get sodium alginate solution;

[0076] Step two: add oil-proof cellulose nanocrystals to the chitosan solution, stir evenly, add sodium alginate solution, stir evenly, add calcium alginate, emulsifier Tween 80 and glycerol, carnauba wax emulsion, stir evenly to get bio-based fluorine-free oil-proof agent;

[0077] The bio-based fluorine-free oil-proof agent comprises the following ingredients by weight: 2.5 parts of chitosan solution, 2.5 parts of sodium alginate solution, 0.15 parts of calcium alginate, 0.3 parts of oil-proof cellulose nanocrystal, 1.5 parts of emulsifier Tween 80, 1.5 parts of glycerol, 2.5 parts of carnauba wax emulsion;

[0078] The preparation process of the oil-proof cellulose nanocrystal comprises the following steps:

[0079] S1: Preparation of cellulose nanocrystal:

[0080] Take the rice chaff, crush, and pass through an 80-mesh sieve, wash and dry; take 100 g of rice chaff powder and 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 2 h, filter, wash and dry to obtain treated rice chaff powder; take 10 g of the treated rice chaff powder and add it to 2000 mL of 80°C deionized water, resuspend for 1.3 h, then add 0.1 g of α-amylase (4000 U / g), stir at 28°C for 3.5 h, adjust the pH to 11, add 1 g of papain, and stir at 78°C for 1 h, centrifuge, wash and dry to obtain a precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide and 100 mL of deionized water, stir to obtain a bleaching solution; take 4 g of the precipitate and 100 mL of the bleaching solution, stir at 78°C for 2 h, filter, wash and dry to obtain rice chaff fiber; take 4 g of the rice chaff fiber and 60 mL of 62% sulfuric acid solution, stir to hydrolyze, centrifuge, dialyze, ultrasonic disperse at 150 W ultrasonic power for 35 min, filter and dry to obtain cellulose nanocrystal;

[0081] S2: Preparation of cellulose nanocrystal-Zein complex:

[0082] Take 2.5 g of zein and 100 mL of deionized water, heat to 72°C and stir for 60 min to obtain a zein solution; add 0.5 g of cellulose nanocrystal and 2.2 g of silane coupling agent 570 to the zein solution, stir at 62°C for 60 min to obtain a cellulose nanocrystal-zein complex;

[0083] S3: Preparation of oil-proof cellulose nanocrystal:

[0084] Take 2 g of the cellulose nanocrystal-zein complex and 30 mL of deionized water, stir for 1.5 h, add 0.15 g of chitosan, and stir for 2.5 h to obtain oil-proof cellulose nanocrystal;

[0085] Step three: preparation of oil-proof paper:

[0086] Add 7 kg of bio-based fluorine-free oil-proof agent to 100 kg of paper pulp, stir evenly, shape, press, dry, and obtain oil-proof paper with a thickness of 0.01 mm.

[0087] Comparative Example 3: The cellulose nanocrystal-soy protein composite was not modified with chitosan, and the rest was the same as Example 1.

[0088] Step one: add 1 g of chitosan powder to 50 mL of acetic acid solution, stir until completely dissolved to form a chitosan solution; dissolve 1 g of sodium alginate in 50 mL of water, stir evenly to obtain a sodium alginate solution;

[0089] Step two: add the oil-proof cellulose nanocrystal to the chitosan solution, stir evenly, add the sodium alginate solution, stir evenly, add calcium alginate, emulsifier Tween 80 and glycerol, carnauba wax emulsion, stir evenly to obtain a bio-based fluorine-free oil-proof agent;

[0090] The bio-based fluorine-free oil-proof agent comprises the following ingredients by weight: 2.5 parts of chitosan solution, 2.5 parts of sodium alginate solution, 0.15 parts of calcium alginate, 0.3 parts of oil-proof cellulose nanocrystal, 1.5 parts of emulsifier Tween 80, 1.5 parts of glycerol, 2.5 parts of carnauba wax emulsion;

[0091] The preparation process of the oil-proof cellulose nanocrystal comprises the following steps:

[0092] S1: Preparation of cellulose nanocrystal:

[0093] Take the rice chaff, crush, pass through an 80-mesh sieve, wash and dry; take 100 g of rice chaff powder, 1000 mL of 4% sodium hydroxide solution, stir at 90°C for 2 h, filter, wash and dry to obtain treated rice chaff powder; take 10 g of treated rice chaff powder, add to 2000 mL of 80°C deionized water, resuspend for 1.3 h, then add 0.1 g of α-amylase (4000 U / g), stir at 28°C for 3.5 h, adjust the pH to 11, add 1 g of papain, and stir at 78°C for 1 h, centrifuge, wash and dry to obtain a precipitate; take 1.8 g of sodium hypochlorite, 7.5 g of glacial acetic acid, 2.8 g of sodium hydroxide, 100 mL of deionized water, stir evenly to obtain a bleaching solution; take 4 g of the precipitate, 100 mL of the bleaching solution, stir at 78°C for 2 h, filter, wash and dry to obtain rice chaff fiber; take 4 g of rice chaff fiber, 60 mL of 62% sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialyze, ultrasonic dispersion at 150 W ultrasonic power for 35 min, filter and dry to obtain cellulose nanocrystal;

[0094] S2: Preparation of cellulose nanocrystal-corn protein composite:

[0095] Take 2.5 g of zein, 100 mL of deionized water, heat to 72℃, stir for 60 min, get zein solution; add 0.5 g of cellulose nanocrystal, 2.2 g of silane coupling agent 570 to the zein solution, stir at 62℃ for 60 min, get cellulose nanocrystal-zein complex;

[0096] S3: Preparation of oil-proof cellulose nanocrystal:

[0097] Take 0.6 g of polyhydroxyalkanoate, 30 mL of dichloromethane, stir evenly, add 2 g of cellulose nanocrystal-zein complex, stir for 2 h, get oil-proof cellulose nanocrystal;

[0098] Step three: Preparation of oil-proof paper:

[0099] Add 7 kg of bio-based fluorine-free oil-proof agent to 100 kg of paper pulp, stir evenly, shape, squeeze, dry, get oil-proof paper with thickness of 0.01 mm.

[0100] Experiment:

[0101] Take the oil-proof paper prepared by example 1 to example 3, comparative example 1 to comparative example 3, test its performance, refer to GB / T12914-2018 to test the tensile index of the oil-proof paper; test the water contact angle of the oil-proof paper to characterize its hydrophobicity, test the hot oil penetration time of the oil-proof paper under room temperature environment with 90℃ edible hot oil, the data obtained are shown in the following table:

[0102] Tensile index kN / m 2 ]]> Water contact angle / ° Protection against 90°C hot oil / min Example 1 33.47 107 175 Example 2 33.43 106 170 Example 3 33.49 107 175 Comparative Example 1 31.25 94 135 Comparative Example 2 32.88 101 155 Comparative Example 3 27.61 97 145

[0103] Conclusion: From the data comparison, the hydrophobicity of the cellulose nanocrystal is reduced, the oil resistance is poor, and the paper will appear hot oil penetration phenomenon after 155 min in the comparative example 1 without adding zein. The oil resistance of the cellulose nanocrystal is poor in the comparative example 2 without using polyhydroxy fatty acid ester to modify the cellulose nanocrystal-soy protein composite. The compatibility of the cellulose nanocrystal-soy protein composite in the matrix is poor, the strength of the oil-proof paper is poor, the tensile index is low, the oil-proof effect of the oil-proof agent is poor, and the hydrophobicity of the paper is reduced in the comparative example 3 without using chitosan to modify the cellulose nanocrystal-soy protein composite. In the examples 1-3 of the application, the zein is compounded with the cellulose nanocrystal to prepare the cellulose nanocrystal-soy protein composite. The zein has good biocompatibility, degradability and oil-proof performance. The hydrophobicity of the cellulose nanocrystal can be improved by compounding the zein with the cellulose nanocrystal, so that the oil droplets are not easy to adhere or penetrate. The oil-proof effect of the oil-proof agent is improved by using the polyhydroxy fatty acid ester to further modify the cellulose nanocrystal-soy protein composite, and the compatibility in the biobased fluorine-free oil-proof agent matrix is improved by adding the chitosan, the dispersibility of the oil-proof cellulose nanocrystal is improved, and the hydrophobicity of the oil-proof agent is further improved.

[0104] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments but can be implemented in other embodiments without departing from the scope of the application. The scope of the application is therefore only defined by the appended claims and not by the above description, which is intended to be exemplary rather than limiting. It is intended to embrace all technical equivalents falling within the meaning and range of equivalents of the essential features of the claims.

Claims

1. A process for the preparation of a bio-based, fluoro-free, oil repellent, characterized in that: The method comprises the following steps: Step one: take polyhydroxyalkanoate, dichloromethane, stir evenly, add cellulose nanocrystal-corn zein complex, stir for 1-2h, add chitosan, stir for 2-3h, get oil-proof cellulose nanocrystal; Step two: add chitosan powder to acetic acid solution, stir until completely dissolved, form chitosan solution; dissolve sodium alginate in deionized water, stir evenly, get sodium alginate solution; Step three: add oil-proof cellulose nanocrystal to chitosan solution, stir evenly, add sodium alginate solution, stir evenly, add calcium alginate, emulsifier and glycerol, carnauba wax emulsion, stir evenly, get bio-based fluorine-free oil-proof agent; The preparation method of the cellulose nanocrystal-corn zein complex is: take corn zein, deionized water, heat to 70-75℃, stir for 50-70min, get corn zein solution; add cellulose nanocrystal and silane coupling agent 570 to the corn zein solution, stir at 60-65℃ for 50-70min, get cellulose nanocrystal-corn zein complex; In step one, the mass ratio of polyhydroxyalkanoate, cellulose nanocrystal-corn zein complex and chitosan is (0.5-0.7):(1.7-2.2):(0.1-0.2).

2. The process for preparing a bio-based fluoro-free oil repellent according to claim 1, characterized in that: The bio-based fluorine-free oil-proof agent comprises the following ingredients, by weight: 2-3 parts of chitosan solution, 2-3 parts of sodium alginate solution, 0.1-0.2 parts of calcium alginate, 0.2-0.4 parts of oil-proof cellulose nanocrystal, 1-2 parts of emulsifier, 1-2 parts of glycerol, 2-3 parts of carnauba wax emulsion.

3. The process for preparing a bio-based fluoro-free oil repellent according to claim 1, characterized in that: The mass ratio of corn zein, cellulose nanocrystal, silane coupling agent 570 and deionized water is (2.3-2.8):(0.4-0.6):(2-2.5):

100.

4. The process for preparing a bio-based fluoro-free oil repellent according to claim 1, characterized in that: The emulsifier is Tween 80.

5. The preparation process of a bio-based fluorine-free oil repellent according to claim 1, characterized in that: The preparation method of the cellulose nanocrystal is: take rice bran, crush, sieve, wash, dry, get rice bran powder; take rice bran powder and sodium hydroxide solution, stir at 90℃ for 1-3h, filter, wash, dry, get treated rice bran powder, take the treated rice bran powder, add to deionized water, resuspend for 1-1.5h, then add alpha-amylase, stir at 25-30℃ for 3-4h, adjust pH to 11, add papain, and stir at 75-80℃ for 1h, centrifuge, wash, dry, get precipitate; take sodium hypochlorite, glacial acetic acid, sodium hydroxide and deionized water, stir evenly, get bleaching solution; take the precipitate and the bleaching solution, stir at 75-80℃ for 1.5-2.5h, filter, wash, dry, get rice bran fiber; take the rice bran fiber and sulfuric acid solution, stir evenly, hydrolyze, centrifuge, dialyze, ultrasonic dispersion for 30-40min, filter, dry, get cellulose nanocrystal.

6. The process for preparing a bio-based fluoro-free oil repellent according to claim 5, characterized in that: The power of ultrasonic dispersion is 150W-200W.

7. A bio-based fluorine-free oil-proof agent prepared by the preparation process of claim 1-6.