Modified emulsifier, emulsion, preparation method of emulsion and waterproof and oilproof paper

Abstract

The invention provides a modified emulsifier, an emulsion, a preparation method of the emulsion and waterproof and oilproof paper. The modified emulsifier comprises at least one of a polymerizable emulsifier and a polymer emulsifier, and the molecular structure of the modified emulsifier comprises a silicon acrylate functional group. According to the invention, the emulsifier is modified, so that the molecular structure of the emulsifier comprises a silicon acrylate functional group, the hydrophobicity of the modified emulsifier is improved, the stain resistance of a coating film is improved, and more choices are provided for the application of the emulsifier.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer chemistry, and in particular to a modified emulsifier, an emulsion, a method for preparing the emulsion, and waterproof and oil-proof paper. Background Art

[0002] Soap-free emulsions, a new type of emulsion that has emerged in recent years, utilize non-soap emulsifiers in the reaction process. These emulsions exhibit environmental friendliness, excellent film-forming properties, and high-temperature stability. Consequently, they are increasingly used in the preparation of coatings, adhesives, and composite materials. However, existing non-soap emulsifiers used in emulsion polymerization suffer from poor water and oil resistance, which complicates their production and use. Summary of the Invention

[0003] To address the above-mentioned issues, the present invention provides a modified emulsifier, an emulsion, a method for preparing the emulsion, and waterproof and oil-proof paper. By modifying the emulsifier to include a silicone acrylate functional group in its molecular structure, the present invention enhances the hydrophobicity of the modified emulsifier and improves the stain resistance of the coating, providing more application options.

[0004] To this end, the first object of the present invention is to provide a modified emulsifier.

[0005] The second object of the present invention is to provide a soap-free emulsion.

[0006] The third object of the present invention is to provide a method for preparing a soap-free emulsion.

[0007] A fourth object of the present invention is to provide a waterproof and oil-proof paper.

[0008] To achieve the first object of the present invention, the technical solution of the present invention provides a modified emulsifier, which includes: at least one of a polymerizable emulsifier and a high molecular weight emulsifier, and the molecular structure of the modified emulsifier includes a silicone acrylate functional group.

[0009] Compared with existing technologies, this technical solution achieves the following technical benefits: the polymerizable emulsifier not only provides emulsification but also participates in the formation of a polymer network during the polymerization reaction, enhancing the performance and stability of the final product; the high molecular weight of the polymer emulsifier forms a more stable protective layer around the dispersed phase droplets, effectively preventing the droplets from re-agglomerating, thereby improving the stability of the emulsification effect. By modifying the emulsifier to include silicone acrylate functional groups in its molecular structure, the present invention enhances the hydrophobicity of the modified emulsifier and improves the stain resistance of the coating, providing more application options.

[0010] In one technical solution of the present invention, the polymerizable emulsifier includes at least one of methacrylic acid type, acrylamide type, styrene type, maleic anhydride type, allyl type, allyl special alcohol ether sulfate, allyl phosphate, nonionic double-bond polyether and allyl alkyl succinate.

[0011] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the emulsifier of the present invention selects a polymerizable emulsifier. Compared with the traditional soap-based emulsifier, the polymerizable emulsifier contains both hydrophilic and lipophilic groups and polymerizable functional groups in its molecular structure. Therefore, they not only have the advantages of traditional surfactants, but can also undergo homopolymerization or copolymerization reaction with the core layer material in the emulsion under certain conditions, thereby improving the film-forming property and water resistance of the emulsion, and having better mechanical properties.

[0012] In one technical solution of the present invention, the polymer emulsifier includes: at least one of: cationic artificial synthetic polymer emulsifier, anionic artificial synthetic polymer emulsifier, anionic and nonionic artificial synthetic polymer emulsifier, anionic and cationic artificial synthetic polymer emulsifier, nonionic artificial synthetic polymer emulsifier, anionic natural polymer emulsifier, anionic and cationic natural polymer emulsifier, nonionic natural polymer emulsifier, and cationic natural polymer emulsifier.

[0013] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: cationic synthetic polymer emulsifiers help to neutralize negatively charged particles and promote aggregation between particles; anionic synthetic polymer emulsifiers can effectively bind to negatively charged surfaces and provide good emulsification and dispersion efficiency; anionic and nonionic synthetic polymer emulsifiers combine the advantages of anionic and nonionic emulsifiers and are used to adapt to environments with different pH values or electrolyte concentrations; anionic and cationic synthetic polymer emulsifiers can carry positive and negative charges in their structure at the same time, making them perform well in specific applications. Unique emulsification and adsorption properties; non-ionic synthetic polymer emulsifiers are highly stable and not affected by electrolytes, and can be used in emulsions that require a lower critical micelle concentration and stronger temperature stability; anionic natural polymer emulsifiers, such as polysaccharides and proteins, can be used in the food and pharmaceutical industries and are widely accepted because of their natural origin and biocompatibility; anionic and cationic natural polymer emulsifiers play a key role in specific biological processes; non-ionic natural polymer emulsifiers have good skin affinity and moisturizing properties; cationic natural polymer emulsifiers have specific biological functions. The polymer emulsifiers of the present invention include various types, which can be synthetic or of natural origin. Above, those skilled in the art can make a selection based on the polymer emulsifier disclosed in this application in combination with specific application requirements.

[0014] To achieve the second purpose of the present invention, the technical solution of the present invention provides a soap-free emulsion, which includes: a modified emulsifier as described in any of the above technical solutions; an acrylate monomer, which includes at least one of methyl methacrylate, butyl acrylate, ethyl acrylate and isooctyl acrylate; a long-chain acrylate monomer, which includes at least one of octadecyl methacrylate and isobornyl methacrylate; a cross-linked acrylate monomer, which includes at least one of 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate and trimethylolpropane triacrylate; a hydrophilic monomer, which includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate and 4-hydroxybutyl acrylate; and a carboxylic acid monomer, which includes at least one of methacrylic acid and acrylic acid.

[0015] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: the soap-free emulsion of the present invention abandons the traditional soap-based emulsifier and uses a polymerizable emulsifier and a high-molecular emulsifier, so that the emulsion is easier to form a film, more environmentally friendly, and has better high-temperature stability. The emulsifier is modified to enhance its water and oil resistance. The emulsion is applied to a monomer emulsion including a water-soluble acrylic resin, retaining the many advantages of the water-soluble acrylic resin, such as good leveling, high gloss, good film formation, and good coating density, while also enhancing its water and oil resistance.

[0016] To achieve the third object of the present invention, the technical solution of the present invention provides a method for preparing a soap-free emulsion, which is used to prepare the soap-free emulsion according to any of the above technical solutions. The preparation method comprises: S100, adding a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier into a reactor to carry out a polymerization reaction to obtain a modified emulsifier; S200, adding acrylate monomer, long carbon chain acrylate monomer, cross-linked acrylate monomer, hydrophilic monomer and carboxylic acid monomer to the modified emulsifier, stirring evenly to obtain a pre-emulsion; S300, adding a first initiator to the pre-emulsion to obtain a soap-free emulsion.

[0017] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the preparation method of the soap-free emulsion of the present invention can prepare the soap-free emulsion by modifying the emulsifier, mixing and emulsifying. The preparation method is simple, efficient and environmentally friendly, which helps to promote the large-scale production and application of soap-free emulsion technology.

[0018] In one technical solution of the present invention, S100 specifically includes: S110, uniformly mixing a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier, and adding the mixture to a solvent; S120, heating under an inert gas atmosphere, and adding a second initiator to carry out a polymerization reaction to obtain a modified emulsifier; In S110, the monomer with silicone acrylate functional group, polymerizable emulsifier or polymer emulsifier and solvent are in a ratio of (50-80): (20-50): (80-120) in parts by mass; and / or in S120, the second initiator includes: at least one of persulfate, peroxide and azo initiator; and / or in S120, the heating temperature is 55°C-65°C; and / or in S120, the polymerization reaction temperature is 60°C-65°C; and / or in S120, the polymerization reaction time is 10h-40h.

[0019] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: the reaction is carried out under the protective atmosphere of inert gas, oxygen is excluded, and oxygen is prevented from inhibiting the polymerization reaction or causing unnecessary side reactions, thereby ensuring the stability and safety of the polymerization reaction; the feed ratio of the monomer with silicone acrylate functional group, the polymerizable emulsifier or the high molecular weight emulsifier and the solvent is adjusted to ensure the uniformity and efficiency of the reaction; the polymerization rate is regulated by controlling the heating temperature, polymerization temperature and time, and the appropriate temperature can ensure that the modified emulsifier has an ideal molecular weight and distribution of silicone acrylate functional groups.

[0020] In one technical solution of the present invention, S200 specifically includes: adding a pH regulator to a modified emulsifier, and then adding an acrylate monomer, a long-chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer and a carboxylic acid monomer, stirring evenly to obtain a pre-emulsion; wherein, in S200, the amount of the pH regulator added is 0.25wt%-1wt% of the modified emulsifier; and / or in S200, the ratio of the acrylate monomer, the long-chain acrylate monomer, the cross-linked acrylate monomer, the hydrophilic monomer and the carboxylic acid monomer in parts by mass is (40-60): (10-30): (10-30): (0-10): (0-10).

[0021] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the present invention adds a pH regulator to the modified emulsifier to improve the stability of the emulsion; and optimizes the mass ratio of the remaining monomers in the emulsion, further ensuring the uniformity and stability of the shell.

[0022] In one technical solution of the present invention, S300 specifically includes: S310, preparing an initiator solution; S320, adding 30%-50% of the pre-emulsion and 5%-35% of the initiator solution into the reactor for activation treatment to obtain an activated solution; S330, adding the remaining pre-emulsion and the remaining initiator solution, performing aging treatment, adjusting the pH to 7-8, and obtaining a soap-free emulsion; Among them, in S310, the mass concentration of the initiator solution is 0.005-0.1; and / or in S320, the temperature of the activation treatment is 70℃-80℃; and / or in S320, the time of the activation treatment is 10min-20min; and / or in S330, the temperature of the aging treatment is 75℃-85℃; and / or in S330, the time of the aging treatment is 90min-150min.

[0023] Compared with existing technologies, this technical solution achieves the following technical effects: The preparation method of the present invention uses activation treatment to fully react the initiator with some monomers to form active centers. The activation treatment is controlled at a temperature of 70°C-80°C and for 10 to 20 minutes. This temperature and time control is crucial to ensure reaction uniformity and avoid premature droplet formation. The aging treatment is carried out at 75°C-85°C for 90 to 150 minutes to ensure complete polymerization. After aging, the pH is adjusted to 7-8 to help stabilize the emulsion.

[0024] In one technical solution of the present invention, the first initiator includes at least one of persulfate, peroxide and azo initiator.

[0025] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: persulfate is a commonly used water-soluble initiator, suitable for the aqueous polymerization system of the present invention, and generates sulfate free radicals through thermal decomposition, thereby initiating the polymerization reaction of the monomer; the peroxide initiator can provide highly active free radicals to effectively start the polymerization reaction; the decomposition rate of the azo initiator is stable and easy to control.

[0026] To achieve the fourth object of the present invention, the technical solution of the present invention provides a waterproof and oil-proof paper, the surface of which is adhered with a soap-free emulsion as described in any of the above technical solutions.

[0027] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the waterproof and oil-proof paper of this technical solution includes the soap-free emulsion of any technical solution of the present invention, and thus has all the beneficial effects of the soap-free emulsion of any technical solution of the present invention, which will not be repeated here. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0029] An embodiment of the present invention provides a modified emulsifier, which includes at least one of a polymerizable emulsifier and a high molecular weight emulsifier, and a silicon acrylate functional group is included in the molecular structure of the modified emulsifier.

[0030] Polymerizable emulsifiers not only provide emulsification but also participate in the formation of a polymer network during the polymerization reaction, enhancing the performance and stability of the final product. Due to their high molecular weight, polymer emulsifiers can form a more stable protective layer around dispersed phase droplets, effectively preventing the droplets from re-agglomerating, thereby improving the stability of the emulsification effect. The present invention modifies the emulsifier to include silicone acrylate functional groups in its molecular structure, increasing the hydrophobicity of the modified emulsifier and improving the stain resistance of the coating film, thus providing more application options.

[0031] In one embodiment of the present invention, the polymerizable emulsifier includes at least one of methacrylic acid type, acrylamide type, styrene type, maleic anhydride type, allyl type, allyl special alcohol ether sulfate, allyl phosphate, nonionic double bond-containing polyether and allyl alkyl succinate.

[0032] For example, the methacrylic acid type includes methacrylate.

[0033] For example, the acrylamide type includes at least one of sodium acrylamidoisopropylsulfonate (A-2405), sodium acrylamido-2-methylpropanesulfonate (COPS-2), and A-2404.

[0034] For example, the styrene type includes polystyrene sulfonic acid (PSS).

[0035] For example, the maleic anhydride type includes maleic acid derivatives.

[0036] For example, the allyl type includes at least one of vinyl sulfonate (SVS), allyl ether sulfonate (COPS-1), allyloxy nonylphenol polyoxyethylene ether ammonium sulfate, allyloxy decyl polyoxyethylene ether ammonium sulfate, and allyloxy alkyl polyoxyethylene ether (ammonium sulfonate).

[0037] For example, the allyl specialty alcohol ether sulfate includes at least one of NRS-10, NRS-1025, NRS-1230, V-10S, V-20S, and V-1025S.

[0038] For example, the allyl phosphate includes at least one of allyl phosphate ammonium salt (anionic type, COP-3), APE2003, APE-2005, APE-2012, UCAN-3, UCAN-4, V-100P, and V-200P.

[0039] For example, the nonionic double-bond-containing polyether is at least one of AE-100, AE-200, AE-300, AE-320, AE-3218, and AE-330.

[0040] For example, the allyl alkyl succinate includes at least one of NRS-138, NRS-320, M-10S, M-12S, M-16S, M-20S, and M-30S.

[0041] The emulsifier of the present invention is a polymerizable emulsifier. Compared with traditional soap-based emulsifiers, polymerizable emulsifiers contain both hydrophilic and lipophilic groups and polymerizable functional groups in their molecular structure. Therefore, they not only have the advantages of traditional surfactants, but can also undergo homopolymerization or copolymerization reactions with core layer materials in the emulsion under certain conditions, thereby improving the film-forming property and water resistance of the emulsion and improving the mechanical properties.

[0042] In one embodiment of the present invention, the polymer emulsifier includes: at least one of: cationic synthetic polymer emulsifier, anionic synthetic polymer emulsifier, anionic and nonionic synthetic polymer emulsifier, anionic and cationic synthetic polymer emulsifier, nonionic synthetic polymer emulsifier, anionic natural polymer emulsifier, anionic and cationic natural polymer emulsifier, nonionic natural polymer emulsifier, and cationic natural polymer emulsifier.

[0043] For example, the cationic synthetic polymer emulsifier includes at least one of Jinhao JH-5020A, DMDAAC / MA / AM, quaternary ammonium salt monomer and acrylamide copolymer, polyvinylbenzyltrimethylamine salt, alkylaminoacrylate copolymer, modified polyethyleneimine, and 1-dodecyl-4-vinylpyridinium bromide.

[0044] For example, the anionic synthetic polymer emulsifier includes at least one of potassium sulfonate of BA / AA and St / MA copolymers, condensed naphthylbenzene sulfonate, and polyacrylate.

[0045] For example, the synthetic polymer emulsifier having both anionic and nonionic properties includes at least one of MAA / SMA / PEGMA and MA / St / PEGMA.

[0046] For example, anionic and cationic synthetic polymer emulsifiers include amino acids.

[0047] For example, the non-ionic synthetic polymer emulsifier includes at least one of PVA, polyethers, polyesters, glucose starch maltose grafted polystyrene (side chain modified), and propylene glycol and ethylene glycol block copolymers.

[0048] For example, the anionic natural polymer emulsifier includes at least one of (2-hydroxy-3-dodecyloxy)propyl carboxymethyl chitosan (HDP-CMCHS), HNP-CMCHS, HBP-CMCHS, carboxymethyl starch, and lignin sulfonate.

[0049] For example, the anionic and cationic natural polymer emulsifier includes at least one of APCTSS, tetradecyl ammonium chloride-modified carboxymethyl cellulose, dodecyl ammonium chloride-modified carboxymethyl starch, and betaines.

[0050] For example, nonionic natural polymer emulsifiers include HBP-HPCHS, HDP-HPCHS, HBP-SCCHS, C 12 -C 24 Hydroxyethyl cellulose, PEAGE modified HEC, PFAPATs modified HEC, HEC / NPEO N A / MMA、CMC / R 12 EO N A. CMC / NPEO N A. CMC / R 12 EO N At least one of A / St, starch succinate, starch acetate, starch octenylsuccinate, starch dodecenylsuccinate, SPAN, TWEEN (both of which are developed based on sorbitol), glucosamide, and dodecyl glucoside.

[0051] For example, cationic natural polymer emulsifiers include glucosamine diacetate.

[0052] Cationic synthetic polymer emulsifiers help neutralize negatively charged particles and promote interparticle aggregation; anionic synthetic polymer emulsifiers effectively bind to negatively charged surfaces, providing excellent emulsification and dispersion performance; anionic-nonionic synthetic polymer emulsifiers combine the advantages of both anionic and nonionic emulsifiers and are designed to adapt to environments with varying pH values or electrolyte concentrations; anionic and cationic synthetic polymer emulsifiers can carry both positive and negative charges within their structure, giving them unique emulsification and adsorption properties in specific applications; nonionic synthetic polymer emulsifiers are highly stable and unaffected by electrolytes, making them suitable for emulsions requiring a low critical micelle concentration and strong temperature stability; anionic natural polymer emulsifiers, such as polysaccharides and proteins, are used in the food and pharmaceutical industries and are widely accepted for their natural origin and biocompatibility; anionic and cationic natural polymer emulsifiers play key roles in specific biological processes; nonionic natural polymer emulsifiers exhibit good skin compatibility and moisturizing properties; and cationic natural polymer emulsifiers possess specific biological functions. The polymer emulsifiers of the present invention include various types, which can be artificially synthesized or naturally derived. Those skilled in the art can select the polymer emulsifiers disclosed in this application based on specific application requirements.

[0053] An embodiment of the present invention provides a soap-free emulsion, which includes: a modified emulsifier as described in any of the above embodiments; an acrylate monomer, which includes at least one of methyl methacrylate, butyl acrylate, ethyl acrylate, and isooctyl acrylate; a long-chain acrylate monomer, which includes at least one of octadecyl methacrylate and isobornyl methacrylate; a cross-linked acrylate monomer, which includes at least one of 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate; a hydrophilic monomer, which includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, and 4-hydroxybutyl acrylate; and a carboxylic acid monomer, which includes at least one of methacrylic acid and acrylic acid.

[0054] The soap-free emulsion of the present invention abandons traditional soap-based emulsifiers and uses polymerizable emulsifiers and high-molecular emulsifiers, making the emulsion easier to form a film, more environmentally friendly, and better in high-temperature stability. The emulsifier is modified to enhance its water and oil resistance. The emulsion is applied to a monomer emulsion including a water-soluble acrylic resin, retaining the advantages of the water-soluble acrylic resin, such as good leveling, high gloss, good film formation, and good film density, while also enhancing its water and oil resistance.

[0055] An embodiment of the present invention provides a method for preparing a soap-free emulsion, which is used to prepare the soap-free emulsion according to any of the above embodiments. The preparation method comprises: S100, adding a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier into a reactor to carry out a polymerization reaction to obtain a modified emulsifier; S200, adding acrylate monomer, long carbon chain acrylate monomer, cross-linked acrylate monomer, hydrophilic monomer and carboxylic acid monomer to the modified emulsifier, stirring evenly to obtain a pre-emulsion; S300, adding a first initiator to the pre-emulsion to obtain a soap-free emulsion.

[0056] By way of example, monomers including silicon acrylate functional groups include methacryloxypropyltris(trimethylsiloxy)silane.

[0057] The preparation method of the soap-free emulsion of the present invention can prepare the soap-free emulsion by modifying the emulsifier, mixing and emulsifying. The preparation method is simple, efficient and environmentally friendly, and is conducive to promoting the large-scale production and application of soap-free emulsion technology.

[0058] In one embodiment of the present invention, S100 specifically includes: S110, uniformly mixing a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier, and adding the mixture to a solvent; S120, heating under an inert gas atmosphere, and adding a second initiator to carry out a polymerization reaction to obtain a modified emulsifier; In S110, the monomer with silicone acrylate functional group, polymerizable emulsifier or polymer emulsifier and solvent are in a ratio of (50-80): (20-50): (80-120) in parts by mass; and / or in S120, the second initiator includes: at least one of persulfate, peroxide and azo initiator; and / or in S120, the heating temperature is 55°C-65°C; and / or in S120, the polymerization reaction temperature is 60°C-65°C; and / or in S120, the polymerization reaction time is 10h-40h.

[0059] The reaction is carried out under a protective atmosphere of inert gas to exclude oxygen, prevent oxygen from inhibiting the polymerization reaction or causing unnecessary side reactions, and ensure the stability and safety of the polymerization reaction; adjust the feed ratio of the silicone acrylate functional monomer, polymerizable emulsifier or high molecular emulsifier and solvent to ensure the uniformity and efficiency of the reaction; and control the heating temperature, polymerization temperature and time to regulate the polymerization rate. The appropriate temperature can ensure that the modified emulsifier has an ideal molecular weight and distribution of silicone acrylate functional groups.

[0060] In one embodiment of the present invention, S200 specifically includes: adding a pH regulator to a modified emulsifier, and then adding an acrylate monomer, a long-chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer and a carboxylic acid monomer, stirring evenly to obtain a pre-emulsion; wherein, in S200, the amount of the pH regulator added is 0.25wt%-1wt% of the modified emulsifier; and / or in S200, the ratio of the acrylate monomer, the long-chain acrylate monomer, the cross-linked acrylate monomer, the hydrophilic monomer and the carboxylic acid monomer in parts by mass is (40-60): (10-30): (10-30): (0-10): (0-10).

[0061] The present invention adds a pH regulator to the modified emulsifier to improve the stability of the emulsion; and optimizes the mass ratio of other monomers in the emulsion to further ensure the uniformity and stability of the shell.

[0062] In one embodiment of the present invention, S300 specifically includes: S310, preparing an initiator solution; S320, adding 30%-50% of the pre-emulsion and 5%-35% of the initiator solution into the reactor for activation treatment to obtain an activated solution; S330, adding the remaining pre-emulsion and the remaining initiator solution, performing aging treatment, adjusting the pH to 7-8, and obtaining a soap-free emulsion; Among them, in S310, the mass concentration of the initiator solution is 0.005-0.1; and / or in S320, the temperature of the activation treatment is 70℃-80℃; and / or in S320, the time of the activation treatment is 10min-20min; and / or in S330, the temperature of the aging treatment is 75℃-85℃; and / or in S330, the time of the aging treatment is 90min-150min.

[0063] The preparation method of the present invention uses an activation treatment to fully react the initiator with some monomers to form active centers. The activation treatment is controlled at a temperature of 70°C-80°C and for 10 to 20 minutes. This temperature and time control is crucial to ensure reaction uniformity and avoid premature droplet formation. The aging treatment is carried out at 75°C-85°C for 90 to 150 minutes to ensure complete polymerization. After aging, the pH is adjusted to 7-8 to help stabilize the emulsion.

[0064] In one embodiment of the present invention, the first initiator includes at least one of persulfate, peroxide and azo initiator.

[0065] Persulfate is a commonly used water-soluble initiator suitable for the aqueous polymerization system of the present invention. It generates sulfate free radicals through thermal decomposition, which in turn initiates the polymerization reaction of the monomer. Peroxide initiators can provide highly active free radicals to effectively start the polymerization reaction. Azo initiators have a stable decomposition rate and are easy to control.

[0066] An embodiment of the present invention provides a waterproof and oil-proof paper, the surface of which is adhered with a soap-free emulsion according to any of the above embodiments.

[0067] The waterproof and oil-proof paper of this embodiment includes the soap-free emulsion of any embodiment of the present invention, and thus has all the beneficial effects of the soap-free emulsion of any embodiment of the present invention, which will not be described in detail here.

[0068] [Example 1] This embodiment provides a soap-free emulsion, and the preparation method thereof is as follows.

[0069] S100, adding 50 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 50 parts by mass of hydroxyethyl methacrylate to a reactor, performing a polymerization reaction, and obtaining a modified emulsifier; S200, adding 0.5 wt% of sodium bicarbonate to the modified emulsifier, and then adding 50 parts by mass of methyl methacrylate, 20 parts by mass of butyl acrylate, 20 parts by mass of octadecyl methacrylate and 10 parts by mass of hydroxyethyl methacrylate, stirring evenly to obtain a pre-emulsion; S300, adding a first initiator to the pre-emulsion to obtain a soap-free emulsion; S100 specifically includes: S110, adding 50 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 50 parts by mass of hydroxyethyl methacrylate to a reactor, and adding the mixture to 100 parts by mass of propylene glycol methyl ether acetate; S120, under a nitrogen atmosphere, heating to 60° C., adding AIBN, and reacting at 60° C. for 20 h to obtain a modified emulsifier with a solid content of approximately 50%; S300 specifically includes: S310, dissolving 5 parts by mass of sodium persulfate in 100 parts by mass of deionized water to prepare an initiator solution; S320, adding 50% of the pre-emulsion and 20% of the initiator solution into the reactor, activating at 75° C. for 15 minutes to obtain an activated solution; S330, add the remaining pre-emulsion and the remaining initiator solution (dropwise completed in 3 hours), heat to 80°C and mature for 2 hours, adjust the pH to 7-8, and obtain a soap-free emulsion; [Example 2] This embodiment provides a soap-free emulsion, and its preparation method is similar to that of Example 1, except that, in S100, 40 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 60 parts by mass of polystyrene sulfonic acid are added to a reactor for polymerization reaction to obtain a modified emulsifier.

[0070] [Example 3] This embodiment provides a soap-free emulsion, and its preparation method is similar to that of Example 1, except that, in S100, 60 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 40 parts by mass of hydroxyethyl methacrylate are added to a reactor to carry out a polymerization reaction to obtain a modified emulsifier.

[0071] [Comparative Example] This comparative example provides a soap-free emulsion, and its preparation method is similar to that of Example 1, except that, in S100, 50 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 50 parts by mass of hydroxyethyl methacrylate are added to the reactor without performing a polymerization reaction.

[0072] Paper product processing methods: 1. Surface sizing: Test paper type: pure wood pulp thin paper, weight 40g / m 2 .

[0073] Preparation of sizing solution: Oxidized cassava starch is used as sizing starch, which is gelatinized at high temperature and diluted with water to 7.5% solid content, and the waterproof and oil-repellent agent is added in an amount of 1%-5% by weight of the concentration in the starch solution (the amount is the wet weight of the waterproof and oil-repellent agent, not the dry weight).

[0074] Processing steps: Surface sizing of paper products (control the coating amount at 1-2g / m 2 ), and dried at 150℃ for 40s to obtain the treated paper products.

[0075] Table 2 shows the performance test results of pure wood pulp tissue paper.

[0076] 2. Surface coating: Test paper type: Kraft paper, dry weight 120g / m 2 .

[0077] Treatment steps: Apply the waterproof and oil-proof agent evenly on the paper to be treated through a wire rod, and control the coating amount to 5-10g / m 2 range, and dried at 150°C for 40s to obtain a treated paper product.

[0078] Table 1 shows the performance test results of pure wood pulp kraft paper.

[0079] 3. Wet end addition: Pulp molded bowl: weight 25g, pulp composition: sugarcane pulp board + bamboo pulp board.

[0080] Processing steps: the pulp board is subjected to pulping treatment, the beating degree reaches 23-27sr, the pulp concentration is 1%, and the synthesized waterproof and oil-proof agent is added in an amount of 1-10wt% of the dry paper weight, preferably 3-6%.

[0081] The treated pulp is filtered through a paper bowl mold according to a specified weight, and then the water is filtered out by vacuum extraction. The paper mold after preliminary dehydration is dried at 190°C for 90 seconds to obtain a treated paper plastic bowl.

[0082] Table 3 shows the performance test results of pulp molded bowls.

[0083] Performance testing: 1. Oil repellency evaluation: ①TAPPI T559 Kit Test ②High temperature oil resistance test: Drip 95°C hot oil (salad oil, peanut oil, rapeseed oil) onto the surface of the paper product, or pour the hot oil into the pulp mold (or make the treated paper into a container that can hold liquids), observe for 30 minutes to see if there is any penetration, and then rate and score it (mainly used in the pulp molding industry).

[0084] 5 points: no surface discoloration after 30 minutes, no oil absorption; 4 points: After 30 minutes, the surface edge changes color slightly and absorbs oil to a certain extent; 3 points: after 30 minutes, the surface changes color and there is slight spotting; 2 points: severe penetration after 30 minutes; 1 point means serious penetration within 5 minutes.

[0085] 2. Waterproof evaluation: ①Cobb test: The test is carried out according to GB / T1540-2002 or ISO 535:1991.

[0086] ②Hot water resistance test: This method directly tests the ability of paper to resist hot water. Generally, the treated paper can be made into a container that can hold liquids, and 100°C boiling water is poured into it. The paper is observed for 30 minutes to see if there is any leakage. If there is no leakage, it passes the test. This method is also directly applicable to pulp molded products.

[0087] Table 1 Performance test results of kraft paper in the examples and comparative examples Table 2 Performance test results of tissue paper in Examples and Comparative Examples Table 3 Performance test results of paper bowls in Examples and Comparative Examples As can be seen from Tables 1-3, the soap-free emulsions of Examples 1-3 of the present invention have good water and oil resistance, are more stable under high temperature conditions, and are less likely to change color due to modification of the polymer emulsifier and the polymerizable emulsifier.

[0088] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0089] The writing methods of "S100", "S200" and "S300" in this specification are for the convenience of describing the embodiments of the present invention. The present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the order of the specific embodiments written in the above manner.

[0090] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A modified emulsifier, characterized in that: The modified emulsifier includes at least one of a polymerizable emulsifier and a high molecular weight emulsifier, and the molecular structure of the modified emulsifier includes a silicon acrylate functional group.

2. The modified emulsifier according to claim 1, characterized in that The polymerizable emulsifier includes at least one of methacrylic acid type, acrylamide type, styrene type, maleic anhydride type, allyl type, allyl special alcohol ether sulfate, allyl phosphate, nonionic double-bond polyether and allyl alkyl succinate.

3. The modified emulsifier according to claim 1, characterized in that The polymer emulsifier includes: at least one of: cationic artificial synthetic polymer emulsifier, anionic artificial synthetic polymer emulsifier, anionic and nonionic artificial synthetic polymer emulsifier, anionic and cationic artificial synthetic polymer emulsifier, nonionic artificial synthetic polymer emulsifier, anionic natural polymer emulsifier, anionic and cationic natural polymer emulsifier, nonionic natural polymer emulsifier, and cationic natural polymer emulsifier.

4. A soap-free emulsion, characterized in that The emulsion comprises: The modified emulsifier according to any one of claims 1 to 3; an acrylate monomer, wherein the acrylate monomer comprises at least one of methyl methacrylate, butyl acrylate, ethyl acrylate, and isooctyl acrylate; A long carbon chain acrylate monomer, wherein the long carbon chain acrylate monomer comprises at least one of octadecyl methacrylate and isobornyl methacrylate; A cross-linked acrylate monomer, wherein the cross-linked acrylate monomer comprises at least one of 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate; A hydrophilic monomer, wherein the hydrophilic monomer comprises at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, and 4-hydroxybutyl acrylate; The carboxylic acid monomer includes at least one of methacrylic acid and acrylic acid.

5. A method for preparing a soap-free emulsion, for preparing the soap-free emulsion according to claim 4, characterized in that: The preparation method comprises: S100, adding a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier into a reactor to carry out a polymerization reaction to obtain a modified emulsifier; S200, adding an acrylate monomer, a long carbon chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer, and a carboxylic acid monomer to the modified emulsifier, and stirring uniformly to obtain a pre-emulsion; S300, adding a first initiator to the pre-emulsion to obtain the soap-free emulsion.

6. The preparation method according to claim 5, characterized in that The S100 specifically includes: S110, uniformly mixing a monomer including a silicon acrylate functional group and a polymerizable emulsifier or a high molecular weight emulsifier, and adding the mixture to a solvent; S120, heating under an inert gas atmosphere, and adding a second initiator to carry out a polymerization reaction to obtain a modified emulsifier; Wherein, in S110, the monomer of the silicone acrylate functional group, the polymerizable emulsifier or the polymer emulsifier and the solvent are in a mass ratio of (50-80): (20-50): (80-120); and / or In S120, the second initiator includes: at least one of persulfate, peroxide and azo initiator; and / or In S120, the heating temperature is 55°C-65°C; and / or In S120, the polymerization reaction temperature is 60° C.-65° C.; and / or In S120, the polymerization reaction time is 10 hours to 40 hours.

7. The preparation method according to claim 5, characterized in that The step S200 specifically includes: adding a pH adjuster to the modified emulsifier, and then adding an acrylate monomer, a long carbon chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer, and a carboxylic acid monomer, and stirring uniformly to obtain a pre-emulsion; Wherein, in S200, the amount of the pH regulator added is 0.25wt%-1wt% of the modified emulsifier; and / or In S200, the mass ratio of the acrylate monomer, the long carbon chain acrylate monomer, the cross-linked acrylate monomer, the hydrophilic monomer and the carboxylic acid monomer is (40-60): (10-30): (10-30): (0-10): (0-10).

8. The preparation method according to claim 5, characterized in that The S300 specifically includes: S310, preparing an initiator solution; S320, adding 30%-50% of the pre-emulsion and 5%-35% of the initiator solution into the reactor for activation treatment to obtain an activated solution; S330, adding the remaining pre-emulsion and the remaining initiator solution, performing aging treatment, adjusting the pH to 7-8, and obtaining the soap-free emulsion; Wherein, in S310, the mass concentration of the initiator solution is 0.005-0.1; and / or In S320, the activation treatment temperature is 70°C-80°C; and / or In S320, the activation treatment time is 10 min-20 min; and / or In S330, the temperature of the aging treatment is 75°C-85°C; and / or In S330, the aging treatment time is 90 minutes to 150 minutes.

9. The preparation method according to claim 5, characterized in that The first initiator includes at least one of persulfate, peroxide and azo initiator.

10. A waterproof and oil-proof paper, characterized in that: The soap-free emulsion according to claim 4 is adhered to the surface of the waterproof and oil-proof paper.

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