Core-shell structure emulsion, preparation method and waterproof and oilproof paper

Abstract

The invention provides a core-shell structure emulsion, a preparation method and waterproof and oilproof paper. The emulsion with the core-shell structure comprises a shell layer and a core layer, wherein the shell layer comprises a methacryloyloxypropyl tri (trimethylsiloxane) silane copolymer and a polymerizable emulsifier; the core layer comprises a polymerizable emulsifier. The emulsion with the core-shell structure has the advantages of being good in water and oil resistance, more stable under a high-temperature condition and easy to form a film.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer chemistry, and in particular to a core-shell structure emulsion, a preparation method and waterproof and oil-proof paper. Background Art

[0002] As people's quality of life improves, they increasingly prioritize the safety, functionality, and environmental friendliness of their daily necessities. Waterproof and oil-resistant paper is finding increasing application in a wide range of everyday paper products, particularly in food packaging. This requires not only waterproof and oil-resistant properties but also the ability to prevent food contamination and environmental pollution.

[0003] Currently, most paper water and oil repellents on the market use traditional emulsifiers. These agents have poor hydrophobicity, are easily oxidized and discolored at high temperatures, hinder emulsion film formation, and have a certain impact on the environment. Summary of the Invention

[0004] To solve the above problems, the present invention provides a core-shell structure emulsion, a preparation method and waterproof and oil-proof paper. The core-shell structure emulsion of the present invention has the advantages of good waterproof and oil-proof properties, greater stability under high temperature conditions and easy film formation.

[0005] To this end, the first object of the present invention is to provide a core-shell structure emulsion.

[0006] The second object of the present invention is to provide a method for preparing a core-shell structure emulsion.

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

[0008] To achieve the first objective of the present invention, the technical solution of the present invention provides a core-shell structure emulsion, which includes: a shell layer, the shell layer includes a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer and a polymerizable emulsifier; and a core layer, the core layer includes a polymerizable emulsifier.

[0009] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: both the core and shell layers of the core-shell structure emulsion of the present invention include a polymerizable emulsifier, which can react with the monomers in the dispersed phase of the core layer, making the core-shell structure emulsion more water-resistant, more stable under high temperature conditions, less prone to oxidative discoloration, and the core-shell structure emulsion formed thereby easier to form a film; the shell layer of the core-shell structure emulsion also includes a methacryloxypropyl tris(trimethylsiloxane)silane copolymer, which combines the characteristics of an organosilicon compound and the performance of a polymer. The organosilicon compound is used to protect the surface of an object from corrosion and contamination by grease, water or other liquids. In the present invention, a small amount of methacryloxypropyl tris(trimethylsiloxane)silane copolymer in the shell layer can exert the effect equivalent to that of a sufficient amount of methacryloxypropyl tris(trimethylsiloxane)silane copolymer, so that the core-shell structure emulsion of the present invention has better water and oil resistance while reducing costs.

[0010] In one technical solution of the present invention, the methacryloxypropyl tris(trimethylsiloxy)silane copolymer includes at least one of a methacryloxypropyl tris(trimethylsiloxy)silane-alcohol copolymer, a methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer, and a methacryloxypropyl tris(trimethylsiloxy)silane-sulfonic acid amine copolymer.

[0011] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the methacryloxypropyl tris(trimethylsiloxane)silane copolymer of the present invention includes a guiding active group, and the methacryloxypropyl tris(trimethylsiloxane)silane is grafted onto the polymerizable emulsifier through the guiding active group.

[0012] 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.

[0013] 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.

[0014] In one technical solution of the present invention, the core layer also includes: an acrylate monomer, the acrylate monomer includes at least one of methyl methacrylate, butyl acrylate, ethyl acrylate and isooctyl acrylate; a long-chain acrylate monomer, the long-chain acrylate monomer includes at least one of octadecyl methacrylate and isobornyl methacrylate; a cross-linked acrylate monomer, the cross-linked acrylate monomer includes at least one of 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate; a hydrophilic monomer, the hydrophilic monomer includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, methacrylic acid, and acrylic acid; and a carboxylic acid monomer, the carboxylic acid monomer includes at least one of methacrylic acid and acrylic acid.

[0015] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the core layer of the core-shell structure emulsion of the present invention also includes a monomer of a water-soluble acrylic resin. The water-soluble acrylic resin has many advantages such as good leveling, high gloss, good film formation and good coating density, which can significantly improve the safety and reliability of the construction and curing process, and retain the advantages of solvent-based acrylic resin in mechanical properties, protective properties and decorative properties.

[0016] To achieve the second object of the present invention, the technical solution of the present invention provides a method for preparing a core-shell structure emulsion, which is used to prepare the core-shell structure emulsion according to any of the above technical solutions. The preparation method comprises: S100, adding a core layer raw material and a first initiator into a reactor and emulsifying them to obtain an emulsion; S200, adding the shell layer raw material and the second initiator to the emulsion obtained in S100, performing a polymerization reaction, and obtaining a core-shell structure emulsion.

[0017] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: the core-shell structure emulsion obtained by the core-shell structure emulsion of the present invention is stable and not prone to stratification or agglomeration; the preparation method is simple, which helps to promote the large-scale production and industrial application of emulsion coating technology.

[0018] In one technical solution of the present invention, S100 specifically includes: S110, adding an acrylate monomer, a long carbon chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer, a carboxylic acid monomer, and a polymerizable emulsifier into a high-speed stirrer and stirring to obtain a core layer liquid; S120, preparing a first initiator into an aqueous solution, taking 1% wt-10% wt of the first initiator aqueous solution and 1% wt-10% wt of the core layer liquid to obtain a pre-emulsion; S130, adding the remaining first initiator aqueous solution and the remaining core layer liquid dropwise to the pre-emulsion to obtain an emulsion.

[0019] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the core layer raw materials of the present invention are first mixed and sheared and dispersed uniformly by high-speed stirring; then a preliminary emulsification structure is formed by pre-emulsification to improve the stability of the emulsion, adjust the rate of the polymerization reaction, and avoid too fast or too slow polymerization reaction; finally, the remaining first initiator and the core layer liquid are emulsified to ensure the quality, stability and uniformity of the product.

[0020] In one technical solution of the present invention, in S120, the stirring temperature is 75°C-90°C; and / or in S120, the stirring time is 10 min-20 min; and / or in S130, the stirring temperature is 75°C-90°C; and / or in S130, the stirring time is 30 min-90 min; and / or in S100, the first initiator includes at least one of persulfate, peroxide and azo initiator.

[0021] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the present invention specifically controls the reaction conditions of the core layer emulsification, ensuring the progress of the emulsification reaction and the stability and performance of the final emulsion.

[0022] In one technical solution of the present invention, S200 specifically includes: S210, preparing a methacryloxypropyl tris(trimethylsiloxy)silane copolymer; S220, uniformly mixing a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer, a polymerizable emulsifier, and a second initiator, and performing a polymerization reaction to obtain a shell polymer; S230, adding the shell polymer to the emulsion obtained in S100, reacting to obtain a core-shell structure emulsion.

[0023] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the present invention first synthesizes a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer so that its molecular chain has a guiding active group; then the shell polymer is added to the emulsion to obtain an emulsion with a core-shell structure having stability and specific functional properties.

[0024] In one technical solution of the present invention, in S220, the temperature of the polymerization reaction is 80°C-85°C; and / or in S220, the temperature of the polymerization reaction is 80°C-85°C; and / or in S230, the reaction time is 10 min-20 min; and / or in S200, the second initiator includes at least one of persulfate, peroxide and azo initiator.

[0025] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the present invention specifically controls the reaction conditions of S200 to ensure the progress of the polymerization reaction and the stability and performance of the final emulsion.

[0026] To achieve the third 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 core-shell structure 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 core-shell structure emulsion of any technical solution of the present invention, and thus has all the beneficial effects of the core-shell structure 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 core-shell structure emulsion, comprising: a shell layer comprising a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer and a polymerizable emulsifier; and a core layer comprising a polymerizable emulsifier.

[0030] The core-shell structure emulsion of the present invention includes a polymerizable emulsifier in both the core and shell layers. The polymerizable emulsifier can react with monomers in the dispersed phase of the core layer, thereby making the core-shell structure emulsion more water-resistant, more stable under high-temperature conditions, less susceptible to oxidative discoloration, and more likely to form a film. The shell layer of the core-shell structure emulsion also includes a methacryloxypropyl tris(trimethylsiloxane)silane copolymer. The methacryloxypropyl tris(trimethylsiloxane)silane copolymer combines the characteristics of an organic silicon compound with the performance of a polymer. The organic silicon compound is used to protect the surface of an object from corrosion and contamination by grease, water or other liquids. In the present invention, a small amount of methacryloxypropyl tris(trimethylsiloxane)silane copolymer in the shell layer can achieve the same effect as a sufficient amount of methacryloxypropyl tris(trimethylsiloxane)silane copolymer, thereby making the core-shell structure emulsion of the present invention have better water and oil resistance while reducing costs.

[0031] In one embodiment of the present invention, the methacryloxypropyl tris(trimethylsiloxy)silane copolymer includes at least one of a methacryloxypropyl tris(trimethylsiloxy)silane-alcohol copolymer, a methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer, and a methacryloxypropyl tris(trimethylsiloxy)silane-sulfonic acid amine copolymer.

[0032] For example, in the methacryloyloxypropyl tris(trimethylsiloxy)silane-alcohol copolymer, the alcohol monomer includes a hydroxy compound or a hydroxy ester compound.

[0033] For example, in the methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer, the carboxylic acid monomer includes at least one of an alkali-soluble resin or a polyethylene-acrylic acid copolymer.

[0034] For example, the polymerizable emulsifier includes sulfonamide monomers; and the methacryloxypropyl tris(trimethylsiloxy)silane-sulfonamide copolymer includes methacryloxypropyl tris(trimethylsiloxy)silane-polymerizable emulsifier copolymer.

[0035] The methacryloxypropyl tris(trimethylsiloxane)silane copolymer of the present invention comprises a directing reactive group, and the methacryloxypropyl tris(trimethylsiloxane)silane is grafted onto a polymerizable emulsifier via the directing reactive group.

[0036] 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.

[0037] For example, the methacrylic acid type includes methacrylate.

[0038] For example, the acrylamide type includes at least one of sodium acrylamidoisopropylsulfonate (A-2405), sodium acrylamido-2-methylpropanesulfonate (COPS-2), and A-2404.

[0039] For example, the styrene type includes polystyrene sulfonic acid (PSS).

[0040] For example, the maleic anhydride type includes maleic acid derivatives.

[0041] 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).

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] In one embodiment of the present invention, the core layer also includes: an acrylate monomer, the acrylate monomer includes at least one of methyl methacrylate, butyl acrylate, ethyl acrylate and isooctyl acrylate; a long-chain acrylate monomer, the long-chain acrylate monomer includes at least one of octadecyl methacrylate and isobornyl methacrylate; a cross-linked acrylate monomer, the cross-linked acrylate monomer includes at least one of 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate; a hydrophilic monomer, the hydrophilic monomer includes at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, methacrylic acid, and acrylic acid; a carboxylic acid monomer includes at least one of methacrylic acid and acrylic acid.

[0048] The core layer of the core-shell structure emulsion of the present invention also includes monomers of a water-soluble acrylic resin. The water-soluble acrylic resin has many advantages such as good leveling, high gloss, good film formation and good coating density, which can significantly improve the safety and reliability during the construction and curing process, and retains the advantages of solvent-based acrylic resin in mechanical properties, protective properties and decorative properties.

[0049] An embodiment of the present invention provides a method for preparing a core-shell structure emulsion, which is used to prepare the core-shell structure emulsion as described in any of the above embodiments. The preparation method comprises: S100, adding a core layer raw material and a first initiator into a reactor and emulsifying them to obtain an emulsion; S200, adding the shell layer raw material and the second initiator to the emulsion obtained in S100, performing a polymerization reaction, and obtaining a core-shell structure emulsion.

[0050] The core-shell structure emulsion obtained by the core-shell structure emulsion of the present invention is stable and not prone to stratification or agglomeration; the preparation method is simple, and is helpful to promote the large-scale production and industrial application of emulsion coating technology.

[0051] In one embodiment of the present invention, S100 specifically includes: S110, adding an acrylate monomer, a long carbon chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer, a carboxylic acid monomer, and a polymerizable emulsifier into a high-speed stirrer and stirring to obtain a core layer liquid; S120, preparing a first initiator into an aqueous solution, taking 1% wt-10% wt of the first initiator aqueous solution and 1% wt-10% wt of the core layer liquid to obtain a pre-emulsion; S130, adding the remaining first initiator aqueous solution and the remaining core layer liquid dropwise to the pre-emulsion to obtain an emulsion.

[0052] The core layer raw materials of the present invention are first mixed and uniformly dispersed by shearing through high-speed stirring; then a preliminary emulsification structure is formed through pre-emulsification to improve the stability of the emulsion, adjust the rate of the polymerization reaction, and avoid excessively fast or excessively slow polymerization reactions; finally, the remaining first initiator and the core layer liquid are emulsified to ensure the quality, stability and uniformity of the product.

[0053] In one embodiment of the present invention, in S120, the stirring temperature is 75°C-90°C; and / or in S120, the stirring time is 10 min-20 min; and / or in S130, the stirring temperature is 75°C-90°C; and / or in S130, the stirring time is 30 min-90 min; and / or in S100, the first initiator includes at least one of persulfate, peroxide and azo initiators.

[0054] The present invention specifically controls the reaction conditions of the core layer emulsification to ensure the progress of the emulsification reaction and the stability and performance of the final emulsion.

[0055] In one embodiment of the present invention, S200 specifically includes: S210, preparing a methacryloxypropyl tris(trimethylsiloxy)silane copolymer; S220, uniformly mixing a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer, a polymerizable emulsifier, and a second initiator, and performing a polymerization reaction to obtain a shell polymer; S230, adding the shell polymer to the emulsion obtained in S100, reacting to obtain a core-shell structure emulsion.

[0056] For example, when the shell includes a methacryloxypropyl tris(trimethylsiloxane) silane-alcohol copolymer, S210 specifically includes: S211, an alcohol monomer and methacryloxypropyl tris(trimethylsiloxane) silane carry out an alcohol dehydroxylation sulfonylation reaction; S212, an amino monomer is added to the monomer obtained in S211, and an amino monomer is carried out to carry out a dehydroxylation reaction to obtain a methacryloxypropyl tris(trimethylsiloxane) silane-alcohol copolymer; wherein the amino monomer includes acrylamide.

[0057] For example, when the shell includes a methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer, S210 specifically includes: S211, esterification reaction of tert-butyl alcohol monomer and methacryloxypropyl tris(trimethylsiloxy)silane; S212, adding an alcohol monomer to the monomer obtained in S211, performing a substitution reaction, and obtaining a methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer; wherein the alcohol monomer includes at least one of hydroxyethyl methacrylate and 4-hydroxybutyl acrylate.

[0058] For example, when the shell includes a methacryloxypropyl tris(trimethylsiloxane)silane-sulfonic acid amine copolymer, S210 specifically includes: reacting an amino monomer with methacryloxypropyl tris(trimethylsiloxane)silane to obtain a methacryloxypropyl tris(trimethylsiloxane)silane-sulfonic acid amine copolymer; wherein the amino monomer includes at least one of PMADMA and PMAEMA. Those skilled in the art can select the methacryloxypropyl tris(trimethylsiloxane)silane copolymer disclosed in the present invention based on specific application requirements.

[0059] The invention first synthesizes a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer to have a guiding active group on its molecular chain; then adds a shell polymer into an emulsion to obtain an emulsion with a core-shell structure having stability and specific functional properties.

[0060] For example, the directing active groups on the molecular chain of the methacryloxypropyltris(trimethylsiloxy)silane copolymer are unsaturated bonds.

[0061] In one embodiment of the present invention, in S220, the temperature of the polymerization reaction is 80°C-85°C; and / or in S220, the temperature of the polymerization reaction is 80°C-85°C; and / or in S230, the reaction time is 10 min-20 min; and / or in S200, the second initiator includes at least one of persulfate, peroxide and azo initiator.

[0062] The present invention specifically controls the reaction conditions of S200 to ensure the progress of the polymerization reaction and the stability and performance of the final emulsion.

[0063] An embodiment of the present invention provides a waterproof and oil-proof paper, the surface of which is adhered with a core-shell structure emulsion according to any of the above embodiments.

[0064] The waterproof and oil-proof paper of this embodiment includes the core-shell structure emulsion of any embodiment of the present invention, and thus has all the beneficial effects of the core-shell structure emulsion of any embodiment of the present invention, which will not be described in detail here.

[0065] [Example 1] This embodiment provides a core-shell structure emulsion, and the preparation method thereof is as follows.

[0066] S100, adding a core layer raw material and a first initiator into a reactor and emulsifying them to obtain an emulsion; S200, adding the shell layer raw material and the second initiator to the emulsion obtained in S100, performing a polymerization reaction, and obtaining the core-shell structure emulsion; S100 specifically includes: S110, adding 60 parts by mass of methyl methacrylate, 20 parts by mass of butyl acrylate, 20 parts by mass of octadecyl methacrylate, and 400-500 parts by mass of water into a high-speed stirrer, stirring to obtain a core layer liquid; S120, preparing a first initiator aqueous solution by combining 5 parts by mass of persulfate and 100 parts by mass of water, taking 10 parts by mass of the first initiator aqueous solution and 10 parts by mass of the core layer liquid, and activating them at 75° C. for 15 minutes to obtain a pre-emulsion; S130, adding the remaining first initiator aqueous solution and the remaining core layer liquid dropwise to the pre-emulsified product, heating to 80° C., reacting for 60 minutes, and obtaining an emulsion; S200 specifically includes: S210, pre-preparing a methacryloyloxypropyl tris(trimethylsiloxy)silane-hydroxyethyl methacrylate random copolymer solution by a solution polymerization process; S220, uniformly mixing a methacryloyloxypropyl tris(trimethylsiloxy)silane-hydroxyethyl methacrylate random copolymer solution, 0.5 parts by mass of a sodium bicarbonate pH adjuster, 2 parts by mass of COPS-1, and 10 parts by mass of a second initiator, a persulfate, and performing a polymerization reaction to obtain a shell polymer; S230, adding the shell polymer to the emulsion obtained in S100, reacting at 80° C. for 15 min, adjusting the pH of the system to 7-8, cooling and discharging the material to obtain a core-shell structure emulsion; S210 specifically includes: S211, 80 parts by mass of methacryloyloxypropyl tris(trimethylsiloxy)silane and 20 parts by mass of hydroxyethyl methacrylate were stirred and mixed uniformly and slowly added to 100 parts by mass of propylene glycol methyl ether acetate solvent; S212, pass nitrogen for 30 minutes to ensure that the oxygen inside the system is removed as much as possible; S213. Raise the temperature to 60°C, add 1 part by mass of oil-soluble initiator AIBN in portions, and control the temperature at 60°C to react for 10 hours to obtain a methacryloyloxypropyl tris(trimethylsiloxy)silane-hydroxyethyl methacrylate random copolymer solution with a solid content of approximately 50%.

[0067] [Example 2] This embodiment provides a core-shell structure emulsion, and its preparation method is similar to that of Example 1, except that, in S211, 50 parts by mass of methacryloxypropyl tris(trimethylsiloxy)silane and 50 parts by mass of hydroxyethyl methacrylate are stirred and mixed uniformly and slowly added to 100 parts by mass of propylene glycol methyl ether acetate solvent.

[0068] [Example 3] This comparative example provides a core-shell structure emulsion, and its preparation method is similar to that of Example 2, except that S210 further includes: S214, adding 2 parts by mass of sodium hydroxide alkaline reagent to the solution obtained in S213 to assist dissolution, and then adding sulfonyl chloride (the molar ratio of sulfonyl chloride to hydroxyethyl methacrylate is 0.2-0.8:1); S215. Stir and react at room temperature under normal pressure for 2 h, then add acrylate monomer (the molar ratio of acrylate monomer to sulfonyl chloride is 0.5-2:1) and react at 60°C for 3 h.

[0069] [Comparative Example 1] This comparative example provides a core-shell structure emulsion, and its preparation method is similar to that of Example 1, except that in S220, COPS-1 is replaced by a traditional anionic non-compound emulsifier (SDS: peregal = 2:1).

[0070] [Comparative Example 2] This comparative example provides a core-shell structure emulsion, and its preparation method is similar to that of Example 1, except that experimental steps S212 and S213 are omitted.

[0071] Paper product processing methods: 1. Surface sizing: Test paper type: pure wood pulp thin paper, weight 40g / m 2 .

[0072] 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).

[0073] 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.

[0074] Table 2 shows the performance test results of pure wood pulp tissue paper.

[0075] 2. Surface coating: Test paper type: pure wood pulp kraft paper, weight 120g / m 2 .

[0076] 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.

[0077] Table 1 shows the performance test results of pure wood pulp kraft paper.

[0078] 3. Wet end addition: Pulp molded bowl: weight 25g, composed of pulp + sugarcane pulp board.

[0079] 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%.

[0080] 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.

[0081] Table 3 shows the performance test results of pulp molded bowls.

[0082] 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 (mainly used for oil-proof evaluation of paper and plastic products).

[0083] 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.

[0084] 2. Waterproof evaluation: ①Cobb test: The test standard is GB / T1540-2002 or ISO 535:1991.

[0085] 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 is considered a pass. This method is also directly applicable to paper and plastic products.

[0086] 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 core-shell structure emulsions of Examples 1-3 of the present invention have the advantages of good water and oil resistance, greater stability under high temperature conditions, and easy film formation; Comparative Example 1 uses a traditional emulsifier, and the emulsion of Comparative Example 2 contains an ordinary random copolymer. The emulsions of Comparative Examples 1-2 have poor water and oil resistance, poor stability under high temperature, and lower film-forming properties than the core-shell structure emulsions of Examples 1-3 of the present invention.

[0087] 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.

[0088] The writing methods of "S100" and "S200" 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.

[0089] 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 core-shell structure emulsion, characterized in that The core-shell structure emulsion comprises: a shell layer comprising a methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer and a polymerizable emulsifier; A core layer includes a polymerizable emulsifier.

2. The core-shell structure emulsion according to claim 1, characterized in that The methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer comprises: At least one of a methacryloxypropyl tris(trimethylsiloxy)silane-alcohol copolymer, a methacryloxypropyl tris(trimethylsiloxy)silane-carboxylic acid copolymer, and a methacryloxypropyl tris(trimethylsiloxy)silane-sulfonic acid amine copolymer.

3. The core-shell structure emulsion 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.

4. The core-shell structure emulsion according to claim 1, characterized in that The nuclear layer further comprises: 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 includes 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, 4-hydroxybutyl acrylate, methacrylic acid, and acrylic acid; The carboxylic acid monomer includes at least one of methacrylic acid and acrylic acid.

5. A method for preparing a core-shell structure emulsion, for preparing the core-shell structure emulsion according to any one of claims 1 to 4, characterized in that: The preparation method comprises: S100, adding a core layer raw material and a first initiator into a reactor and emulsifying them to obtain an emulsion; S200, adding the shell layer raw material and the second initiator to the emulsion obtained in S100, performing a polymerization reaction, and obtaining the core-shell structure emulsion.

6. The preparation method according to claim 5, characterized in that The S100 specifically includes: S110, adding an acrylate monomer, a long carbon chain acrylate monomer, a cross-linked acrylate monomer, a hydrophilic monomer, a carboxylic acid monomer, and a polymerizable emulsifier into a high-speed stirrer and stirring to obtain a core layer liquid; S120, preparing a first initiator into an aqueous solution, taking 1% wt-10% wt of the first initiator aqueous solution and 1% wt-10% wt of the core layer liquid to obtain a pre-emulsion; S130, adding the remaining first initiator aqueous solution and the remaining core layer liquid dropwise to the pre-emulsion to obtain an emulsion.

7. The preparation method according to claim 6, characterized in that In S120, the stirring temperature is 75°C-90°C; and / or In S120, the stirring time is 10 min-20 min; and / or In S130, the stirring temperature is 75°C-90°C; and / or In S130, the stirring time is 30 min-90 min; and / or In S100, the first initiator includes at least one of persulfate, peroxide, and azo initiator.

8. The preparation method according to claim 5, characterized in that The S200 specifically includes: S210, preparing a methacryloxypropyl tris(trimethylsiloxy)silane copolymer; S220, uniformly mixing the methacryloyloxypropyl tris(trimethylsiloxy)silane copolymer, the polymerizable emulsifier, and the second initiator, and performing a polymerization reaction to obtain a shell polymer; S230, adding the shell polymer to the emulsion obtained in S100, reacting to obtain the core-shell structure emulsion.

9. The preparation method according to claim 8, characterized in that In S220, the polymerization reaction temperature is 80°C-85°C; and / or In S220, the polymerization reaction temperature is 80°C-85°C; and / or In S230, the reaction time is 10 min-20 min; and / or In S200 , the second initiator includes at least one of persulfate, peroxide, and azo initiators.

10. A waterproof and oil-proof paper, characterized in that: The core-shell structure emulsion according to any one of claims 1 to 4 is attached to the surface of the waterproof and oil-proof paper.

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