Fluorine-free oil-proof agent for paper pulp molding and preparation method of fluoride-free oil-proof agent

Abstract

The invention discloses a fluoride-free oil-proof agent for paper pulp molding and a preparation method thereof, and belongs to the technical field of paper pulp molding materials. The fluoride-free oil-proof agent is prepared from the following raw materials in parts by weight: 40 to 60 parts of long-chain alkane, 10 to 20 parts of short-chain alkane, 10 to 15 parts of film-forming agent, 5 to 10 parts of modified polysilazane, 3 to 7 parts of nano material, 1 to 3 parts of chitosan derivative, 0.1 to 3 parts of cross-linking agent, 6 to 10 parts of filler and 60 to 100 parts of solvent. Wherein the modified polysilazane is prepared by reacting polysilazane with methyltriethoxysilane and 3-halogenated propylene under the action of a catalyst and chloroplatinic acid isopropanol. The preparation method comprises the following steps: mixing long-chain alkane, short-chain alkane and a solvent, and heating to react; other components are mixed and subjected to ultrasonic treatment; and mixing the two mixtures under ultrasonic and pressure conditions. The fluoride-free oil-proof agent provided by the invention is environment-friendly and safe, has excellent oil-proof performance, and is suitable for surface treatment of paper pulp molded products.

Description

Technical Field

[0001] The invention relates to the technical field of oil-proofing agents, and in particular to a fluorine-free oil-proofing agent for pulp molding and a preparation method thereof. Background Art

[0002] As an environmentally friendly packaging material, molded pulp products are widely used in food packaging, tableware, medical device packaging, and other fields due to their biodegradability, recyclability, and low cost. However, due to their porous structure and hydrophilicity, molded pulp products are easily penetrated by grease and moisture, resulting in reduced product strength and appearance, seriously affecting their service life and application range. Therefore, waterproofing and oil-proofing pulp molded products has become a key technology to improve their practicality.

[0003] Traditional pulp molding oil-proofing agents primarily use fluorinated compounds, such as perfluorooctanoic acid and its salts (PFOA) and perfluorooctane sulfonic acid and its salts (PFOS). While these fluorinated compounds offer excellent water and oil repellency, they are difficult to degrade, easily accumulate in the environment, and pose potential health risks to humans. Consequently, they have been included in restricted or banned chemical lists in many countries. Therefore, the development of environmentally friendly, highly effective, fluorine-free oil-proofing agents has become a hot topic and a challenge in current research.

[0004] At present, a variety of fluorine-free oil-proofing agents have been developed on the market. CN118461359A discloses a fluorine-free oil-proofing agent for pulp molding, which contains short-chain alkanes, long-chain alkanes, antioxidants, film-forming agents, inorganic ash, solvents and other additives. The oil-proofing agent has certain water and oil-proofing properties, and avoids the harm of fluorine-containing and silicon-containing chemicals in traditional oil-proofing agents to the human body and the environment. CN116905275A discloses a fluorine-free pulp molding surface spray oil-proofing agent, which is prepared by compounding chitosan grafted polysiloxane with enzymatically modified starch to have certain heat oil and hot water resistance. CN117144714A proposes a fluorine-free water and oil-proofing agent for pulp molding surface impregnation, which improves the water and oil resistance by hydrogen bonding, grafting and cross-linking of modified starch, edible gelatin, chitosan and other components.

[0005] Furthermore, CN114164704B discloses a fluorine-free water and oil repellent for use in pulp molding slurries. This oil repellent can be added directly to the pulp to achieve a water and oil repellent effect by filling interfiber spaces or adhering to the fiber surface. CN114086421B describes a composite fluorine-free water and oil repellent based on the crosslinking modification of sodium alginate and polyethylene glycol and the condensation modification of a polydimethylsiloxane derivative.

[0006] However, existing fluorine-free oil repellents still face several technical challenges. First, the oil repellency of most fluorine-free oil repellents lags significantly behind that of fluorine-containing agents, particularly when exposed to high-temperature hot oils, where their effectiveness is significantly reduced. Second, existing fluorine-free oil repellents lack durability, gradually weakening their effectiveness after long-term use or repeated contact with grease. Third, while some fluorine-free oil repellents address the oil repellency issue, they also negatively impact the air permeability and biodegradability of molded pulp products. Fourth, existing fluorine-free oil repellents often struggle to balance both water and hot oil resistance, with their effectiveness significantly reduced at high temperatures. Furthermore, the complex preparation processes and high costs of some fluorine-free oil repellents limit their large-scale application.

[0007] Therefore, there is an urgent need to develop a fluorine-free oil-proof agent for pulp molding that has excellent waterproof and hot oil resistance, simple preparation process, moderate cost and is environmentally friendly, so as to meet the needs of pulp molding products in various application scenarios. Summary of the Invention

[0008] In order to solve the problem of poor water and hot oil resistance of fluorine-free oil-proofing agents for pulp molding and achieve the technical effect of improving the water and oil resistance of pulp molded products, the present invention provides a fluorine-free oil-proofing agent for pulp molding and a preparation method thereof.

[0009] The objective of the present invention is achieved through the following technical solution: A fluorine-free oil-proof agent for pulp molding, comprising the following raw materials in parts by weight: 40-60 parts of long-chain alkanes, 10-20 parts of short-chain alkanes, 10-15 parts of film-forming agents, 5-10 parts of modified polysilazane, 3-7 parts of nanomaterials, 1-3 parts of chitosan derivatives, 0.1-3 parts of cross-linking agents, 6-10 parts of fillers, and 60-100 parts of solvents.

[0010] The fluorine-free oil-proofing agent for pulp molding prepared in the present invention has excellent oil-proofing properties and can effectively prevent grease from penetrating pulp molded products. Through the synergistic effect of long-chain alkanes and short-chain alkanes, a dense hydrophobic layer is formed; the modified polysilazane provides excellent oleophobic properties; the nanomaterial enhances the mechanical strength and stability of the oil-proofing agent; the chitosan derivative improves the binding force between the oil-proofing agent and the pulp; the cross-linking agent enables the components to form a network structure, enhancing the oil-proofing effect; the filler further improves the coverage and stability of the oil-proofing agent. The fluorine-free oil-proofing agent does not contain fluoride, is environmentally friendly and safe, and is degradable, in line with the current development trend of green environmental protection. At the same time, the oil-proofing agent has good film-forming properties and can form a uniform and dense oil-proofing layer on the surface of pulp molded products, effectively blocking grease penetration.

[0011] Preferably, the modified polysilazane comprises the following raw materials in parts by weight: 10-20 parts of polysilazane, 1-3 parts of methyltriethoxysilane, 1-5 parts of 3-halogenated propylene, 0.1-1.0 parts of catalyst, 40-60 parts of organic solvent, and 0.1-1.0 parts of isopropyl chloroplatinate.

[0012] Preferably, the catalyst is at least one of butylammonium fluoride, tetrabutylammonium bromide, and tetrabutylammonium hydrogen sulfate.

[0013] Preferably, the organic solvent is at least one of ethyl acetate, butyl acetate, n-butyl ether, toluene, and cyclohexane.

[0014] Preferably, the modified polysilazane is prepared by the following method:

[0015] A1. Add methyltriethoxysilane, 3-halopropylene and a catalyst to an organic solvent according to parts by weight, mix well, heat to 45-65° C., stir and react for 1-3 hours to obtain a reactant, which is set aside;

[0016] A2. Add the reactants obtained in step A1 and isopropyl chloroplatinic acid to polysilazane according to parts by weight, heat to 50-80° C. and react for 3-5 hours, then cool to obtain modified polysilazane.

[0017] The modified polysilazane prepared by the above-mentioned raw materials and methods in the present invention can provide excellent oleophobic properties for oil repellent. The modification mechanism of modified polysilazane is mainly to react chemically with polysilazane by methyltriethoxysilane and 3-halogenated propene, introduce hydrophobic groups (such as methyl, halogen atoms), thereby reducing the surface energy of the material, improving hydrophobic properties and antifouling properties; catalysts and organic solvents play a role in promoting the reaction and providing a reaction medium during the reaction. By adjusting the type and ratio of raw materials, the performance of modified polysilazane can be further optimized so that the modified organic polysilazane finally obtained has excellent hydrophobic properties, and stains are not easily attached to its surface or are easily wiped off after being attached to its surface, thus having antifouling and self-cleaning functions, and adding an oil repellent can effectively improve the hydrophobic and oleophobic properties of the oil repellent.

[0018] Preferably, the long-chain alkane is at least one of emulsified paraffin, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and polypropylene wax.

[0019] Preferably, the short-chain alkane is at least one of short-chain vinyl alkyl ether and short-chain vinyl carboxylate.

[0020] Preferably, the film-forming agent is at least one of polyvinyl pyrrolidone, polyvinyl alcohol, nanocellulose, carboxymethyl cellulose, sodium alginate, chitosan, and guar gum.

[0021] Preferably, the nanomaterial is nanosilica or nanoclay.

[0022] Preferably, the chitosan derivative is at least one of carboxymethyl chitosan, hydroxypropyl chitosan, chitosan quaternary ammonium salt, and chitosan graft copolymer.

[0023] Preferably, the cross-linking agent is at least one of glutaraldehyde, epichlorohydrin, and glycidyl methacrylate.

[0024] Preferably, the filler is at least one of bentonite, diatomaceous earth, barite, talc, kaolin, mica powder, magnesium powder, and volcanic ash.

[0025] Preferably, the solvent is deionized water or ethylene glycol.

[0026] The present invention also provides a method for preparing a fluorine-free oil-proofing agent for pulp molding, comprising the following steps:

[0027] S1. Add a long-chain alkane, a short-chain alkane, and a solvent to a reaction apparatus according to parts by weight, heat to 60-80° C., and stir to react for 1-3 hours to obtain a mixture A, which is set aside;

[0028] S2. Mixing the film-forming agent, modified polysilazane, nanomaterial, chitosan derivative, crosslinking agent and filler in parts by weight and ultrasonically treating the mixture to obtain a mixture B for later use;

[0029] S3. Add mixture B to mixture A and place in a 40-50 kHz ultrasonic device for ultrasonic treatment for 5-10 minutes. Stir and mix at a pressure of 1.0-1.5 MPa for 60-1000 minutes. After cooling, obtain a fluorine-free oil repellent.

[0030] The beneficial effects of the present invention are:

[0031] 1. The chitosan derivatives used in the present invention can be combined with pulp fibers through hydrogen bonds or electrostatic interactions, significantly improving the adhesion of the coating and solving the problem of weak bonding between traditional oil repellents and pulp molded products.

[0032] 2. The long-chain alkanes and short-chain alkanes in the present invention act as hydrophobic modifiers and are combined with chitosan derivatives through chemical bonds or physical adsorption, thereby effectively reducing the surface energy of the coating and improving the water and oil repellency.

[0033] 3. The cross-linking agent used in the present invention undergoes a cross-linking reaction with the chitosan derivative and the hydrophobic modifier to form a stable three-dimensional network structure, which significantly improves the water resistance and oil resistance of the coating.

[0034] 4. The nanomaterials added in the present invention form a micro-nano structure through the interaction with the base material and the hydrophobic modifier, further improving the waterproof and oil-proof properties of the coating.

[0035] 5. The modified polysilazane introduced in the present invention significantly improves the hydrophobicity, oil resistance and adhesion of the oil repellent, so that the pulp molded products can effectively resist the erosion of hot oil.

[0036] 6. The chitosan derivatives used in the present invention are compounded with synthetic polymer materials to achieve an organic combination of environmental protection and oil-proof performance, which is in line with the current development trend of green environmental protection. DETAILED DESCRIPTION

[0037] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the embodiments. The contents mentioned in the embodiments are not intended to limit the present invention.

[0038] Example 1

[0039] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 50 parts of long-chain alkanes, 15 parts of short-chain alkanes, 12 parts of film-forming agents, 8 parts of modified polysilazane, 5 parts of nanomaterials, 2 parts of chitosan derivatives, 1 part of a cross-linking agent, 8 parts of fillers, and 80 parts of solvents.

[0040] Among them, emulsified paraffin is selected as the long-chain alkane; short-chain vinyl alkyl ether is selected as the short-chain alkane; polyvinyl alcohol is selected as the film-forming agent; nano-silicon dioxide is selected as the nanomaterial; carboxymethyl chitosan is selected as the chitosan derivative; glutaraldehyde is selected as the cross-linking agent; bentonite is selected as the filler; and deionized water is selected as the solvent.

[0041] The modified polysilazane comprises the following raw materials in parts by weight: 15 parts polysilazane, 2 parts methyltriethoxysilane, 3 parts 3-halopropylene, 0.5 parts catalyst, 50 parts organic solvent, and 0.5 parts isopropyl chloroplatinate. The 3-halopropylene is 3-chloropropylene, the catalyst is butylammonium fluoride, and the organic solvent is ethyl acetate.

[0042] The modified polysilazane is prepared by the following method:

[0043] A1. Add 2 parts of methyltriethoxysilane, 3 parts of 3-chloropropylene and 0.5 parts of butylammonium fluoride to 50 parts of ethyl acetate, mix well, heat to 55°C and stir for 2 hours to obtain a reactant, which is set aside.

[0044] A2. Add the reactant obtained in step A1 and 0.5 parts of isopropyl chloroplatinate to 15 parts of polysilazane, heating to 65° C. for 4 hours, and cooling to obtain modified polysilazane.

[0045] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0046] S1. Add 50 parts of long-chain alkane, 15 parts of short-chain alkane and 80 parts of solvent into a reaction apparatus according to parts by weight, heat to 70° C., and stir to react for 2 hours to obtain a mixture A, which is set aside;

[0047] S2. According to parts by weight, 12 parts of a film-forming agent, 8 parts of a modified polysilazane, 5 parts of a nanomaterial, 2 parts of a chitosan derivative, 1 part of a cross-linking agent, and 8 parts of a filler were mixed and ultrasonically treated to obtain a mixture B for later use;

[0048] S3. Add mixture B to mixture A and place in a 45 kHz ultrasonic device for ultrasonic treatment for 8 minutes. Stir and mix at a pressure of 1.2 MPa for 120 minutes. After cooling, obtain a fluorine-free oil repellent.

[0049] The fluorine-free oil-proofing agent for pulp molding prepared in this example exhibits excellent oil-proofing properties, effectively preventing grease from penetrating pulp molded products. The synergistic effect of long-chain and short-chain alkanes forms a dense hydrophobic layer; the modified polysilazane provides excellent oleophobic properties; the nanomaterial enhances the agent's mechanical strength and stability; the chitosan derivative improves the agent's binding to the pulp; the crosslinking agent forms a network structure among the components, enhancing the oil-proofing effect; and the filler further improves the agent's coverage and stability.

[0050] This fluorine-free oil repellent contains no fluoride, is environmentally friendly, safe, and biodegradable, in line with current trends in green environmental protection. It also exhibits excellent film-forming properties, forming a uniform, dense oil-repellent layer on the surface of pulp molded products, effectively preventing grease penetration.

[0051] Example 2

[0052] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 40 parts of long-chain alkanes, 10 parts of short-chain alkanes, 10 parts of film-forming agents, 5 parts of modified polysilazane, 3 parts of nanomaterials, 1 part of chitosan derivatives, 0.1 parts of cross-linking agents, 6 parts of fillers, and 60 parts of solvents.

[0053] Among them, microcrystalline wax is selected as the long-chain alkane; short-chain vinyl carboxylate is selected as the short-chain alkane; nanocellulose is selected as the film-forming agent; nanoclay is selected as the nanomaterial; hydroxypropyl chitosan is selected as the chitosan derivative; epichlorohydrin is selected as the cross-linking agent; diatomaceous earth is selected as the filler; and ethylene glycol is selected as the solvent.

[0054] The modified polysilazane includes the following raw materials in parts by weight: 10 parts of polysilazane, 1 part of methyltriethoxysilane, 1 part of 3-halogenated propylene, 0.1 part of a catalyst, 40 parts of an organic solvent, and 0.1 part of isopropyl chloroplatinate.

[0055] Wherein, the 3-halogenated propylene is selected from 3-bromopropylene, the catalyst is selected from tetrabutylammonium bromide, and the organic solvent is selected from butyl acetate.

[0056] The modified polysilazane is prepared by the following method:

[0057] A1. According to parts by weight, 1 part of methyltriethoxysilane, 1 part of 3-bromopropylene and 0.1 part of tetrabutylammonium bromide were added to 40 parts of butyl acetate and mixed evenly. The mixture was heated to 45° C. and stirred for reaction for 1 hour to obtain a reactant, which was set aside.

[0058] A2. Add the reactant obtained in step A1 and 0.1 part of isopropyl chloroplatinate to 10 parts of polysilazane according to parts by weight, heat to 50° C. and react for 3 hours. Cool and obtain modified polysilazane.

[0059] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0060] S1. Add 40 parts of long-chain alkane, 10 parts of short-chain alkane and 60 parts of solvent into a reaction apparatus according to parts by weight, heat to 60°C, and stir to react for 1 hour to obtain a mixture A, which is set aside;

[0061] S2. Mix 10 parts of a film-forming agent, 5 parts of a modified polysilazane, 3 parts of a nanomaterial, 1 part of a chitosan derivative, 0.1 parts of a cross-linking agent, and 6 parts of a filler according to parts by weight, and then perform ultrasonic treatment to obtain a mixture B for later use;

[0062] S3. Add mixture B to mixture A and place in a 40 kHz ultrasonic device for ultrasonic treatment for 5 minutes. Stir and mix at a pressure of 1.0 MPa for 60 minutes. After cooling, obtain a fluorine-free oil repellent.

[0063] The fluorine-free oil repellent for pulp molding prepared in this example exhibits excellent oil repellency despite the relatively low dosage of each component. Microcrystalline wax, as a long-chain alkane, provides basic hydrophobicity; short-chain carboxylic acid vinyl ester, as a short-chain alkane, enhances the permeability of the oil repellent; nanocellulose, as a film-forming agent, provides excellent film-forming properties; nanoclay enhances the barrier properties of the oil repellent; hydroxypropyl chitosan improves the compatibility of the oil repellent with paper pulp; epichlorohydrin, as a crosslinker, stabilizes the network structure of the components; and diatomaceous earth, as a filler, enhances the coverage and stability of the oil repellent.

[0064] Example 3

[0065] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 60 parts of long-chain alkanes, 20 parts of short-chain alkanes, 15 parts of film-forming agents, 10 parts of modified polysilazane, 7 parts of nanomaterials, 3 parts of chitosan derivatives, 3 parts of cross-linking agents, 10 parts of fillers, and 100 parts of solvents.

[0066] Among them, the long-chain alkane is Fischer-Tropsch wax; the short-chain alkane is a mixture of short-chain vinyl alkyl ether and short-chain carboxylic acid vinyl ester, with a ratio of 1:1; the film-forming agent is polyvinyl pyrrolidone; the nanomaterial is nanosilica; the chitosan derivative is chitosan quaternary ammonium salt; the cross-linking agent is glycidyl methacrylate; the filler is kaolin; and the solvent is deionized water.

[0067] The modified polysilazane includes the following raw materials in parts by weight: 20 parts of polysilazane, 3 parts of methyltriethoxysilane, 5 parts of 3-halogenated propylene, 1.0 part of a catalyst, 60 parts of an organic solvent, and 1.0 part of isopropyl chloroplatinate.

[0068] Wherein, the 3-halogenated propylene is 3-fluoropropylene, the catalyst is tetrabutylammonium hydrogen sulfate, and the organic solvent is toluene.

[0069] The modified polysilazane is prepared by the following method:

[0070] A1. Add 3 parts of methyltriethoxysilane, 5 parts of 3-fluoropropylene and 1.0 part of tetrabutylammonium hydrogen sulfate to 60 parts of toluene, mix well, heat to 65° C. and stir for 3 hours to obtain a reactant, which is set aside.

[0071] A2. Add the reactant obtained in step A1 and 1.0 part of isopropyl chloroplatinate to 20 parts of polysilazane, heating to 80° C. for reaction for 5 hours, and cooling to obtain modified polysilazane.

[0072] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0073] S1. Add 60 parts of long-chain alkane, 20 parts of short-chain alkane and 100 parts of solvent into a reaction apparatus according to parts by weight, heat to 80° C., and stir to react for 3 hours to obtain a mixture A, which is set aside;

[0074] S2. Mix 15 parts of a film-forming agent, 10 parts of a modified polysilazane, 7 parts of a nanomaterial, 3 parts of a chitosan derivative, 3 parts of a cross-linking agent, and 10 parts of a filler according to parts by weight, and then perform ultrasonic treatment to obtain a mixture B for later use;

[0075] S3. Add mixture B to mixture A and place in a 50 kHz ultrasonic device for 10 min, and stir and mix at a pressure of 1.5 MPa for 1000 min. After cooling, obtain a fluorine-free oil repellent.

[0076] The fluorine-free oil-proofing agent for pulp molding prepared in this example uses relatively high amounts of each component, resulting in excellent oil-proofing properties. Fischer-Tropsch wax, as a long-chain alkane, provides excellent hydrophobicity; a mixture of short-chain vinyl alkyl ether and short-chain vinyl carboxylate, as a short-chain alkane, provides a synergistic effect; polyvinyl pyrrolidone, as a film-forming agent, provides excellent film-forming properties; nanosilica enhances the mechanical strength and stability of the oil-proofing agent; chitosan quaternary ammonium salt improves the binding force between the oil-proofing agent and the pulp; glycidyl methacrylate, as a crosslinking agent, enables the components to form a dense network structure; and kaolin, as a filler, further improves the coverage and stability of the oil-proofing agent.

[0077] Example 4

[0078] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 45 parts of long-chain alkanes, 12 parts of short-chain alkanes, 13 parts of film-forming agents, 7 parts of modified polysilazane, 4 parts of nanomaterials, 2 parts of chitosan derivatives, 1.5 parts of cross-linking agents, 7 parts of fillers, and 70 parts of solvents.

[0079] Among them, polyethylene wax is selected as the long-chain alkane; short-chain vinyl alkyl ether is selected as the short-chain alkane; carboxymethyl cellulose is selected as the film-forming agent; nano-silica is selected as the nanomaterial; chitosan graft copolymer is selected as the chitosan derivative; glutaraldehyde is selected as the cross-linking agent; talc powder is selected as the filler; and deionized water is selected as the solvent.

[0080] The modified polysilazane includes the following raw materials in parts by weight: 12 parts of polysilazane, 1.5 parts of methyltriethoxysilane, 2 parts of 3-halogenated propylene, 0.3 parts of a catalyst, 45 parts of an organic solvent, and 0.3 parts of isopropyl chloroplatinate.

[0081] Wherein, 3-halogenated propylene is selected from 3-chloropropylene, butylammonium fluoride is selected as the catalyst, and n-butyl ether is selected as the organic solvent.

[0082] The modified polysilazane is prepared by the following method:

[0083] A1. Add 1.5 parts of methyltriethoxysilane, 2 parts of 3-chloropropylene and 0.3 parts of butylammonium fluoride to 45 parts of n-butyl ether, mix well, heat to 50° C. and stir for 1.5 hours to obtain a reactant, which is set aside.

[0084] A2. Add the reactant obtained in step A1 and 0.3 parts of isopropyl chloroplatinate to 12 parts of polysilazane, heating to 60° C. for reaction for 3.5 hours, and cooling to obtain modified polysilazane.

[0085] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0086] S1. Add 45 parts of long-chain alkane, 12 parts of short-chain alkane and 70 parts of solvent to a reaction apparatus according to parts by weight, heat to 65°C, and stir to react for 1.5 hours to obtain a mixture A, which is set aside;

[0087] S2. Mix 13 parts of a film-forming agent, 7 parts of a modified polysilazane, 4 parts of a nanomaterial, 2 parts of a chitosan derivative, 1.5 parts of a cross-linking agent, and 7 parts of a filler, according to parts by weight, and perform ultrasonic treatment to obtain a mixture B for later use.

[0088] S3. Add mixture B to mixture A and place in a 42 kHz ultrasonic device for ultrasonic treatment for 7 minutes. Stir and mix at a pressure of 1.1 MPa for 180 minutes. After cooling, obtain a fluorine-free oil repellent.

[0089] The fluorine-free oil-proofing agent for pulp molding prepared in this example exhibits excellent oil-proofing properties and stability. Polyethylene wax, as a long-chain alkane, provides excellent hydrophobicity; short-chain vinyl alkyl ether, as a short-chain alkane, enhances the permeability of the oil-proofing agent; carboxymethyl cellulose, as a film-forming agent, provides good film-forming properties; nanosilica enhances the mechanical strength and stability of the oil-proofing agent; chitosan graft copolymer improves the binding force between the oil-proofing agent and the pulp; glutaraldehyde, as a crosslinking agent, enables the components to form a stable network structure; and talc, as a filler, enhances the coverage and stability of the oil-proofing agent.

[0090] Example 5

[0091] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 55 parts of long-chain alkanes, 18 parts of short-chain alkanes, 14 parts of film-forming agents, 9 parts of modified polysilazane, 6 parts of nanomaterials, 2.5 parts of chitosan derivatives, 2 parts of cross-linking agents, 9 parts of fillers, and 90 parts of solvents.

[0092] Among them, polypropylene wax is selected as the long-chain alkane; short-chain carboxylic acid vinyl ester is selected as the short-chain alkane; sodium alginate is selected as the film-forming agent; nanoclay is selected as the nanomaterial; carboxymethyl chitosan is selected as the chitosan derivative; epichlorohydrin is selected as the cross-linking agent; mica powder is selected as the filler; and ethylene glycol is selected as the solvent.

[0093] The modified polysilazane includes the following raw materials in parts by weight: 18 parts of polysilazane, 2.5 parts of methyltriethoxysilane, 4 parts of 3-halogenated propylene, 0.8 parts of a catalyst, 55 parts of an organic solvent, and 0.8 parts of isopropyl chloroplatinate.

[0094] Wherein, the 3-halogenated propylene is selected from 3-bromopropylene, the catalyst is selected from tetrabutylammonium bromide, and the organic solvent is selected from cyclohexane.

[0095] The modified polysilazane is prepared by the following method:

[0096] A1. According to parts by weight, 2.5 parts of methyltriethoxysilane, 4 parts of 3-bromopropylene and 0.8 parts of tetrabutylammonium bromide were added to 55 parts of cyclohexane, mixed evenly, and heated to 60° C. with stirring for reaction for 2.5 hours to obtain a reactant, which was set aside;

[0097] A2. Add the reactant obtained in step A1 and 0.8 parts of isopropyl chloroplatinate to 18 parts of polysilazane, heating to 75° C. for reaction for 4.5 hours, and cooling to obtain modified polysilazane.

[0098] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0099] S1. Add 55 parts of long-chain alkane, 18 parts of short-chain alkane and 90 parts of solvent to a reaction apparatus according to parts by weight, heat to 75°C, and stir to react for 2.5 hours to obtain a mixture A, which is set aside;

[0100] S2. According to parts by weight, 14 parts of a film-forming agent, 9 parts of a modified polysilazane, 6 parts of a nanomaterial, 2.5 parts of a chitosan derivative, 2 parts of a cross-linking agent, and 9 parts of a filler were mixed and ultrasonically treated to obtain a mixture B for later use;

[0101] S3. Add mixture B to mixture A and place in a 48 kHz ultrasonic device for ultrasonic treatment for 9 minutes. Stir and mix at a pressure of 1.3 MPa for 500 minutes. After cooling, obtain a fluorine-free oil repellent.

[0102] The fluorine-free oil-proofing agent for pulp molding prepared in this example exhibits excellent oil-proofing properties and stability. Polypropylene wax, as a long-chain alkane, provides excellent hydrophobicity; short-chain carboxylic acid vinyl ester, as a short-chain alkane, enhances the permeability of the oil-proofing agent; sodium alginate, as a film-forming agent, provides good film-forming properties; nanoclay enhances the barrier properties of the oil-proofing agent; carboxymethyl chitosan improves the affinity of the oil-proofing agent with pulp; epichlorohydrin, as a crosslinking agent, forms a stable network structure among the components; and mica powder, as a filler, enhances the coverage and stability of the oil-proofing agent.

[0103] Example 6

[0104] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 50 parts of long-chain alkanes, 15 parts of short-chain alkanes, 12 parts of film-forming agents, 8 parts of modified polysilazane, 5 parts of nanomaterials, 2 parts of chitosan derivatives, 1 part of a cross-linking agent, 8 parts of fillers, and 80 parts of solvents.

[0105] Among them, the long-chain alkane is a mixture of emulsified paraffin and microcrystalline wax in a ratio of 3:2; the short-chain alkane is a mixture of short-chain vinyl alkyl ether and short-chain carboxylic acid vinyl ester in a ratio of 2:1; the film-forming agent is chitosan; the nanomaterial is a mixture of nano-silica and nano-clay in a ratio of 1:1; the chitosan derivative is hydroxypropyl chitosan; the cross-linking agent is glycidyl methacrylate; the filler is magnesium powder; and the solvent is deionized water.

[0106] The modified polysilazane includes the following raw materials in parts by weight: 15 parts of polysilazane, 2 parts of methyltriethoxysilane, 3 parts of 3-halogenated propylene, 0.5 parts of a catalyst, 50 parts of an organic solvent, and 0.5 parts of isopropyl chloroplatinate.

[0107] The 3-halopropylene is a mixture of 3-chloropropylene and 3-bromopropylene in a ratio of 1:1, the catalyst is tetrabutylammonium hydrogen sulfate, and the organic solvent is a mixture of ethyl acetate and toluene in a ratio of 1:1.

[0108] The modified polysilazane is prepared by the following method:

[0109] A1. Add 2 parts of methyltriethoxysilane, 3 parts of 3-halopropylene and 0.5 parts of tetrabutylammonium hydrogen sulfate to 50 parts of organic solvent, mix well, heat to 55° C. and stir for 2 hours to obtain a reactant, which is set aside.

[0110] A2. Add the reactant obtained in step A1 and 0.5 parts of isopropyl chloroplatinate to 15 parts of polysilazane, heating to 65° C. for 4 hours, and cooling to obtain modified polysilazane.

[0111] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0112] S1. Add 50 parts of long-chain alkane, 15 parts of short-chain alkane and 80 parts of solvent into a reaction apparatus according to parts by weight, heat to 70° C., and stir to react for 2 hours to obtain a mixture A, which is set aside;

[0113] S2. According to parts by weight, 12 parts of a film-forming agent, 8 parts of a modified polysilazane, 5 parts of a nanomaterial, 2 parts of a chitosan derivative, 1 part of a cross-linking agent, and 8 parts of a filler were mixed and ultrasonically treated to obtain a mixture B for later use;

[0114] S3. Add mixture B to mixture A and place in a 45 kHz ultrasonic device for ultrasonic treatment for 8 minutes. Stir and mix at a pressure of 1.2 MPa for 120 minutes. After cooling, obtain a fluorine-free oil repellent.

[0115] The fluorine-free oil-proofing agent for pulp molding prepared in this example exhibits excellent oil-proofing properties and stability through the synergistic effect of multiple components. A mixture of emulsified paraffin and microcrystalline wax, as a long-chain alkane, provides more comprehensive hydrophobicity; a mixture of short-chain vinyl alkyl ether and short-chain vinyl carboxylate, as a short-chain alkane, provides synergistic enhancement; chitosan, as a film-forming agent, provides good film-forming properties; a mixture of nanosilica and nanoclay enhances the mechanical strength and barrier properties of the oil-proofing agent; hydroxypropyl chitosan improves the oil-proofing agent's affinity for paper pulp; glycidyl methacrylate, as a crosslinking agent, enables the components to form a stable network structure; and magnesium powder, as a filler, enhances the coverage and stability of the oil-proofing agent.

[0116] Example 7

[0117] A fluorine-free oil-proofing agent for pulp molding comprises the following raw materials in parts by weight: 42 parts of long-chain alkanes, 11 parts of short-chain alkanes, 11 parts of film-forming agents, 6 parts of modified polysilazane, 4 parts of nanomaterials, 1.5 parts of chitosan derivatives, 0.5 parts of cross-linking agents, 7 parts of fillers, and 65 parts of solvents.

[0118] Among them, polyethylene wax is selected as the long-chain alkane; short-chain vinyl alkyl ether is selected as the short-chain alkane; guar gum is selected as the film-forming agent; nano-silica is selected as the nanomaterial; chitosan quaternary ammonium salt is selected as the chitosan derivative; glutaraldehyde is selected as the cross-linking agent; volcanic ash is selected as the filler; and deionized water is selected as the solvent.

[0119] The modified polysilazane includes the following raw materials in parts by weight: 11 parts of polysilazane, 1.2 parts of methyltriethoxysilane, 1.5 parts of 3-halogenated propylene, 0.2 parts of a catalyst, 42 parts of an organic solvent, and 0.2 parts of isopropyl chloroplatinate.

[0120] Wherein, 3-halopropylene is selected from 3-chloropropylene, butylammonium fluoride is selected as the catalyst, and ethyl acetate is selected as the organic solvent.

[0121] The modified polysilazane is prepared by the following method:

[0122] A1. According to parts by weight, 1.2 parts of methyltriethoxysilane, 1.5 parts of 3-chloropropylene, and 0.2 parts of butylammonium fluoride were added to 42 parts of ethyl acetate and mixed evenly. The mixture was heated to 50° C. and stirred for 1.5 hours to obtain a reactant, which was set aside.

[0123] A2. Add the reactant obtained in step A1 and 0.2 parts of isopropyl chloroplatinate to 11 parts of polysilazane, heating to 55° C. for reaction for 3.5 hours, and cooling to obtain modified polysilazane.

[0124] The preparation method of the fluorine-free oil-proofing agent for pulp molding comprises the following steps:

[0125] S1. Add 42 parts of long-chain alkane, 11 parts of short-chain alkane and 65 parts of solvent to a reaction apparatus according to parts by weight, heat to 65°C, and stir to react for 1.5 hours to obtain a mixture A, which is set aside;

[0126] S2. According to parts by weight, 11 parts of a film-forming agent, 6 parts of a modified polysilazane, 4 parts of a nanomaterial, 1.5 parts of a chitosan derivative, 0.5 parts of a cross-linking agent, and 7 parts of a filler were mixed and ultrasonically treated to obtain a mixture B for later use;

[0127] S3. Add mixture B to mixture A and place in a 42 kHz ultrasonic device for ultrasonic treatment for 6 minutes. Stir and mix at a pressure of 1.1 MPa for 90 minutes. After cooling, obtain a fluorine-free oil repellent.

[0128] The fluorine-free oil-proofing agent for pulp molding prepared in this example exhibits excellent oil-proofing properties and stability. Polyethylene wax, as a long-chain alkane, provides excellent hydrophobicity; short-chain vinyl alkyl ether, as a short-chain alkane, enhances the permeability of the oil-proofing agent; guar gum, as a film-forming agent, provides good film-forming properties; nanosilica enhances the mechanical strength and stability of the oil-proofing agent; chitosan quaternary ammonium salt improves the binding force between the oil-proofing agent and the pulp; glutaraldehyde, as a crosslinking agent, enables the components to form a stable network structure; and volcanic ash, as a filler, enhances the coverage and stability of the oil-proofing agent.

[0129] Comparative Example 1

[0130] The difference between this comparative example and the above-mentioned Example 6 is that no modified polysilazane is added when preparing the oil-proofing agent in this comparative example. The rest of the contents of this comparative example are the same as those of Example 6 and will not be repeated here.

[0131] The oil-proofing agent prepared in Example 6 and the oil-proofing agent prepared in Comparative Example 1 were used to prepare a molded product of the same size and the performance test was conducted.

[0132] After testing, it was found that the oil-proof grade of the pulp molding made using the oil-proof agent in Example 6 could reach 11, the water contact angle was greater than 123.6°, there was no negative seepage, no leakage, and no deformation after 30 minutes of hot water at 100°C, and the mechanical strength of the pulp molding sample fully met the requirements of GB / T 36787-2018; the oil-proof grade of the products obtained in the comparative example was less than 5, and the water contact angle was less than 92.5°.

[0133] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the scope of protection of the present invention.

Claims

1. A fluorine-free oil-proofing agent for pulp molding, characterized in that: The invention comprises the following raw materials in parts by weight: 40-60 parts of long-chain alkane, 10-20 parts of short-chain alkane, 10-15 parts of film-forming agent, 5-10 parts of modified polysilazane, 3-7 parts of nanomaterial, 1-3 parts of chitosan derivative, 0.1-3 parts of cross-linking agent, 6-10 parts of filler and 60-100 parts of solvent.

2. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The modified polysilazane comprises the following raw materials in parts by weight: 10-20 parts of polysilazane, 1-3 parts of methyltriethoxysilane, 1-5 parts of 3-halogenated propylene, 0.1-1.0 parts of a catalyst, 40-60 parts of an organic solvent, and 0.1-1.0 parts of isopropyl chloroplatinate.

3. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The modified polysilazane is prepared by the following method: A1. Add methyltriethoxysilane, 3-halopropylene and a catalyst to an organic solvent according to parts by weight, mix well, heat to 45-65° C., stir and react for 1-3 hours to obtain a reactant, which is set aside; A2. Add the reactants obtained in step A1 and isopropyl chloroplatinic acid to polysilazane according to parts by weight, heat to 50-80° C. and react for 3-5 hours, then cool to obtain modified polysilazane.

4. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The long-chain alkane is at least one of emulsified paraffin, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and polypropylene wax; the short-chain alkane is at least one of short-chain vinyl alkyl ether and short-chain vinyl carboxylate.

5. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The film-forming agent is at least one of polyvinyl pyrrolidone, polyvinyl alcohol, nanocellulose, carboxymethyl cellulose, sodium alginate, chitosan and guar gum.

6. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The nano material is nano silicon dioxide or nano clay; and the solvent is deionized water or ethylene glycol.

7. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The chitosan derivative is at least one of carboxymethyl chitosan, hydroxypropyl chitosan, chitosan quaternary ammonium salt, and chitosan graft copolymer.

8. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The cross-linking agent is at least one of glutaraldehyde, epichlorohydrin, and glycidyl methacrylate.

9. The fluorine-free oil-proofing agent for pulp molding according to claim 1, characterized in that: The filler is at least one of bentonite, diatomaceous earth, barite, talc, kaolin, mica powder, magnesium powder and volcanic ash.

10. A method for preparing the fluorine-free oil-proofing agent for pulp molding according to any one of claims 1 to 9, characterized in that: The steps include: S1. Add a long-chain alkane, a short-chain alkane, and a solvent to a reaction apparatus according to parts by weight, heat to 60-80° C., and stir to react for 1-3 hours to obtain a mixture A, which is set aside; S2. Mixing the film-forming agent, modified polysilazane, nanomaterial, chitosan derivative, crosslinking agent and filler in parts by weight and ultrasonically treating the mixture to obtain a mixture B for later use; S3. Add mixture B to mixture A and place in a 40-50 kHz ultrasonic device for ultrasonic treatment for 5-10 minutes. Stir and mix at a pressure of 1.0-1.5 MPa for 60-1000 minutes. After cooling, obtain a fluorine-free oil repellent.