Cation-based oil-proofing agent for environment-friendly paper and preparation method of cation-based oil-proofing agent

Abstract

The invention relates to the technical field of paper product oil-proofing agents, in particular to a cation-based environment-friendly oil-proofing agent for paper, which comprises the following raw materials: a natural polymer material, an environment-friendly water repellent agent, a cross-linking agent, an emulsifier and water. The natural polymer material is one or more of starch, chitosan, sodium alginate, concentrated whey protein powder, soybean protein isolate or cellulose derivatives; the environment-friendly water repellent agent is one or more of palm wax, paraffin or alkyl ketene dimer; the cross-linking agent is one or more of citric acid and ferulic acid; the emulsifier is one or more of cationic starch graft copolymer, fatty glyceride or lecithin, and the plasticizer is glycerol, polyethylene glycol and sorbitol. The oil-proof agent for the environment-friendly paper is excellent in oil-proof performance, non-toxic and biodegradable, the contact angle is larger than 90 degrees, grease permeation can be effectively prevented, it can be guaranteed that in the packaging process, dryness and cleanliness are kept, the shelf life of food is prolonged, meanwhile, packaging materials are prevented from being corroded by grease, and the integrity and reliability of packaging are improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil-proofing agents for paper products, and in particular to a cationic-based environmentally friendly oil-proofing agent for paper and a preparation method thereof. Background Art

[0002] As people pay more attention to food safety and environmental protection, paper food packaging materials are becoming more and more popular among consumers. However, traditional paper is derived from natural plant fibers, and its own waterproof and oil-proof properties are poor. In practical applications, it is necessary to enhance its ability to block moisture and grease. In recent years, petroleum-based plastics have been used as waterproof and oil-proof barrier materials for some food packaging. However, the difficulty of plastic degradation will bring white pollution to the environment.

[0003] Traditional paper oil-proofing agents mostly use fluorinated compounds (such as PFAS), which have good oil-proofing effects, but are harmful to the environment and human health and difficult to degrade. Existing environmentally friendly oil-proofing agents have poor oil-proofing effects, or have complex preparation processes and high costs. Therefore, a cationic environmentally friendly paper oil-proofing agent and a preparation method thereof are provided. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the conventional paper oil-proofing agent in the prior art that is harmful to the environment and human body and is difficult to degrade, and to propose a cationic-based environmentally friendly paper oil-proofing agent.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A cationic-based environmentally friendly oil-proof agent for paper is designed, which is characterized by comprising the following raw materials: natural polymer materials, environmentally friendly hydrophobic agents, cross-linking agents, emulsifiers and water.

[0006] Preferably, the natural polymer material is one or more of starch, chitosan, sodium alginate, concentrated whey protein, isolated soy protein or cellulose derivatives.

[0007] Preferably, the environmentally friendly hydrophobic agent is one or more of palm wax, paraffin wax or alkyl ketene dimer.

[0008] Preferably, the cross-linking agent is one or more of citric acid and ferulic acid.

[0009] Preferably, the emulsifier is one or more of cationic starch graft copolymer, fatty acid glyceride or lecithin.

[0010] Preferably, the plasticizer is one or more of glycerol, polyethylene glycol and sorbitol.

[0011] A method for preparing a cationic-based oil-proof agent for environmentally friendly paper, characterized in that it comprises the following steps: Step 1: Dissolve the natural polymer materials (chitosan and sodium alginate) in water under acidic conditions, and heat and stir until completely dissolved; Step 2: First, mix and melt the waxy raw materials (palm wax or paraffin) at a temperature of 95-120°C, add a small amount of water and emulsifier, and stir at a temperature of 85-95°C to form an emulsion of oil-in-water (W / O). After standing for 5-10 minutes, transport it to a high-speed shearing machine and add the dissolved substance obtained in step 1 to form a water-in-oil (O / W) material; Step 3: Add crosslinking agent and plasticizer, adjust pH value to 5-7, and continue high-speed shear stirring reaction for 0.5-1 hour; Step 4: Cool to room temperature 20-25°C, filter to obtain an environmentally friendly paper oil-proof agent.

[0012] Preferably, the acetylation degree of chitosan in step 1 is greater than 85%, and the viscosity of sodium alginate is 20-100 mps.

[0013] The beneficial effects of the present invention are: 1. The environmentally friendly paper oil-proof agent is simple to prepare, non-toxic and biodegradable. It can be quickly decomposed in the natural environment after use, and will not cause pollution to the soil, water sources and other ecological environments. It meets environmental protection requirements, helps to reduce white pollution and protect the ecological environment.

[0014] This environmentally friendly paper oil-proof agent has excellent oil-proof performance and a contact angle greater than 90°. It can effectively prevent grease penetration, ensure dryness and cleanliness during the packaging process, extend the shelf life of food, and at the same time avoid grease erosion on packaging materials, thereby improving the integrity and reliability of packaging.

[0015] This environmentally friendly paper oil-proof agent is suitable for a variety of scenarios, such as paper-plastic mold boxes, food packaging paper, fast food packaging paper, etc. It can meet the needs of different food packaging and provide the food industry with an efficient and environmentally friendly packaging experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of the preparation process of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0018] Raw material composition: Natural polymer materials (one or more of starch, chitosan, sodium alginate, whey protein concentrate, soy protein isolate or cellulose derivatives).

[0019] Environmentally friendly hydrophobic agent (such as one or more of palm wax, paraffin, fatty acid ester, alkyl ketene dimer).

[0020] Cross-linking agent (such as one or more of citric acid and ferulic acid).

[0021] Emulsifier (such as one or more of natural starch synthetic emulsifier, fatty acid glyceride, lecithin).

[0022] Water is used as solvent.

[0023] Preparation steps: Step 1: Synthesis of cationic emulsifier: Dissolve natural polymer materials such as corn starch, waxy corn starch, linalool starch and oxidized starch. Preferably, waxy corn starch and linalool starch and oxidized low-viscosity starch are dissolved in water at a concentration of 10-25%, preferably 15-20%, and stir until completely dissolved. Under alkaline conditions, add an etherifying agent and heat to cationize the starch solution. The pH value is 8-13, preferably 12-13. The heat preservation time is 2-5 hours, preferably 3-5 hours, and the temperature is 65-85°C, preferably 70-80°C.

[0024] Adjust the pH value of the cationic starch solution to 3-7. Preferably, it is 4-5. Add acrylamide and methacryloyloxyethyl trimethyl ammonium chloride, dimethylaminoethyl methacrylate, acryloyloxyethyl trimethyl ammonium chloride and initiators ammonium persulfate and potassium persulfate for graft copolymerization. Methacryloyloxyethyl trimethyl ammonium chloride and acryloyloxyethyl trimethyl ammonium chloride are preferred. React for 1-3 hours to prepare a cationic emulsifier.

[0025] Step 2: Add chitosan with a degree of acetylation of 85-99% into a dilute acid solution and dissolve it at a concentration of 2-15%, preferably with a degree of acetylation of 95-99%. Dissolve low-viscosity sodium alginate in a dilute acid solution at 5-10%, and 1% viscosity at 10-100 mcp, preferably 20-50 mcp.

[0026] Step 3: Mix paraffin wax and palm wax according to the ratio. Add alkyl ketene dimer and heat to melt at 90-120℃, preferably 90-105℃, add the above-prepared cationic emulsifier (accounting for 20-80% of the melt, preferably 25-35%) and a small amount of hot water, stir at high speed to form an oil-in-water emulsion, let it stand for 5-10 minutes, quickly pour in the heated chitosan and sodium alginate liquid, and stir for 15-30 minutes.

[0027] Step 4: Add plasticizers glycerol, polyethylene glycol, sorbitol, preferably sorbitol, and crosslinkers citric acid and ferulic acid, preferably ferulic acid, and stir for 20 minutes.

[0028] Step 5: Cool to room temperature and filter to obtain an environmentally friendly oil-proof agent for paper.

[0029] Example 1 Pulp preparation: weigh 12 grams of citrus pulp board and bamboo pulp board (7:3), add water and beat into a pulp liquid with a concentration of 1%, add 0.3 grams (15%) of alkyl ketene dimer emulsion water repellent, stir for 4 minutes, then add 0.36 grams of the prepared oil-proof agent (measured as a percentage of the absolute dry pulp weight), and stir evenly.

[0030] The prepared slurry is poured into a pulp forming machine, and after vacuuming and filtering the water, it is placed in a forming mold and pressed into a paper bowl at 150-180° C., and the preferred film forming temperature is 165-175° C.

[0031] Pour in 60℃ soybean vegetable oil, let it stand for 30 minutes, pour out the vegetable oil and observe the oil penetration on the back. At the same time, use a precision balance to weigh and calculate the oil absorption value. The oil absorption value is 5.2 grams, which is used to determine the oil-proof effect.

[0032] Example 2 Pulp preparation: weigh 12 grams of citrus pulp board and bamboo pulp board (7:3), add water and beat into a pulp liquid with a concentration of 1%, add 0.3 grams (15%) of alkyl ketene dimer emulsion water repellent, stir for 4 minutes, then add 0.48 grams of the prepared oil-proof agent (measured as a percentage of the absolute dry pulp weight), and stir evenly.

[0033] The prepared slurry is poured into a pulp forming machine, and after vacuuming and filtering the water, it is placed in a forming mold and pressed into a paper bowl at 150-180° C., and the preferred film forming temperature is 165-175° C.

[0034] Pour in 60℃ soybean vegetable oil, let it stand for 30 minutes, pour out the vegetable oil and observe the oil penetration on the back. At the same time, use a precision balance to weigh and calculate the oil absorption value. The oil absorption value is 4.6 grams, which is used to determine the oil-proof effect.

[0035] Example 3 Pulp preparation: weigh 12 grams of citrus pulp board and bamboo pulp board (7:3), add water and beat into a pulp liquid with a concentration of 1%, add 0.3 grams (15%) of alkyl ketene dimer emulsion water repellent, stir for 4 minutes, then add 0.6 grams of the prepared oil-proof agent (measured as a percentage of the absolute dry pulp weight), and stir evenly.

[0036] The prepared slurry is poured into a pulp forming machine, and after vacuuming and filtering the water, it is placed in a forming mold and pressed into a paper bowl at 150-180° C., and the preferred film forming temperature is 165-175° C.

[0037] Pour in 60℃ soybean vegetable oil, let it stand for 30 minutes, pour out the vegetable oil and observe the oil penetration on the back. At the same time, use a precision balance to weigh and calculate the oil absorption value. The oil absorption value is 3.3 grams, which is used to determine the oil-proof effect.

[0038] Example 4 Pulp preparation: weigh 12 grams of citrus pulp board and bamboo pulp board (7:3), add water and beat into a pulp liquid with a concentration of 1%, add 0.3 grams (15%) of alkyl ketene dimer emulsion water repellent, stir for 4 minutes, then add 0.72 grams of the prepared oil-proof agent (measured as a percentage of the absolute dry pulp weight), and stir evenly.

[0039] The prepared slurry is poured into a pulp forming machine, and after vacuuming and filtering the water, it is placed in a forming mold and pressed into a paper bowl at 150-180° C., and the preferred film forming temperature is 165-175° C.

[0040] Pour in 60℃ soybean vegetable oil, let it stand for 30 minutes, pour out the vegetable oil and observe the oil penetration on the back. At the same time, use a precision balance to weigh and calculate the oil absorption value to be 2.5 grams to determine the oil-proof effect.

[0041] Note: Pour 50 grams of 60℃ vegetable oil into a standard sample paper bowl (absolute dry weight: 12 grams), let it stand for 30 minutes and pour it out. The calculated oil absorption value is 7.0-2.5 grams for qualified products and 5.0-2.5 grams for high-quality products to determine the oil-proof effect.

[0042] Project Name Comparative Example Embodiment 1 Embodiment 1 Embodiment 3 Embodiment 4 Paper dry pulp weight (g) 12 12 12 12 12 Waterproofing agent 15% (g) 0.3 0.3 0.3 0.3 0.3 Oil-proof agent 35% (g) No 0.36 0.48 0.6 0.72 Oil absorption value (g) 15 5.2 4.6 3.3 2.5 Visual inspection Full penetration Point penetration Impermeable Impermeable Impermeable The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cationic-based oil-proofing agent for environmentally friendly paper, characterized in that: The invention comprises the following raw materials: natural polymer material, environmentally friendly hydrophobic agent, cross-linking agent, emulsifier, plasticizer and water.

2. The cationic-based environmentally friendly paper oil-proofing agent according to claim 1, characterized in that: The natural polymer material is one or more of starch, chitosan, sodium alginate, concentrated whey protein, isolated soy protein or cellulose derivatives.

3. The cationic-based environmentally friendly paper oil-proofing agent according to claim 1, characterized in that: The environmentally friendly hydrophobic agent is one or more of palm wax, paraffin wax or alkyl ketene dimer.

4. The cationic-based environmentally friendly paper oil-proofing agent according to claim 1, characterized in that: The cross-linking agent is one or more of citric acid and ferulic acid.

5. The cationic-based environmentally friendly paper oil-proofing agent according to claim 1, characterized in that: The emulsifier is one or more of cationic starch graft copolymer, fatty acid glyceride or lecithin.

6. The cationic-based environmentally friendly paper oil-proofing agent according to claim 1, characterized in that: The plasticizer is one or more of glycerol, polyethylene glycol or sorbitol.

7. A method for preparing a cationic-based oil-proof agent for environmentally friendly paper, characterized in that: The following steps are involved: Step 1: Dissolve the natural polymer materials (chitosan and sodium alginate) in water under acidic conditions, and heat and stir until completely dissolved; Step 2: Mix and melt the waxy raw materials (palm wax or paraffin) at a temperature of 95-120°C, add a small amount of water and emulsifier, stir at a temperature of 85-95°C to form an emulsion of water-in-oil (W / O), let it stand for 5-10 minutes, then transport it to a high-speed shearing machine and add the dissolved substance obtained in step 1 to form a water-in-oil (O / W) material; Step 3: Add crosslinking agent and plasticizer, adjust pH value to 5-7, and continue high-speed shear stirring reaction for 0.5-1 hour; Step 4: Cool to room temperature 20-25°C, filter to obtain an environmentally friendly paper oil-proof agent.

8. The method for preparing the cationic-based oil-proofing agent for environmentally friendly paper according to claim 7, characterized in that: The acetylation degree of chitosan in step 1 is greater than 85%, and the viscosity of sodium alginate is 20-100 mps.

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