Nano-calcium carbonate modified polyacrylate emulsion and preparation method thereof

Abstract

The present invention discloses a nano-calcium carbonate modified polyacrylate emulsion and a preparation method thereof. The emulsion is prepared from the following raw materials in parts by weight: 30-65 parts of an acrylate mixed monomer, 8-30 parts of a functional monomer, 0.1-1 parts of a modified nano-calcium carbonate emulsion, 1-5 parts of a composite emulsifier, 0.08-0.65 parts of an initiator, 2-4.5 parts of liquidambar resin, 0.02-0.2 parts of a chain transfer agent, 0.1-5 parts of a pH regulator, and 100-155 parts of deionized water. The nano-calcium carbonate modified polyacrylate emulsion can be used as a water-based coating, water-based ink, an environmentally friendly adhesive, textile printing and dyeing, leather finishing, building cement mortar, and as a functional material in other fields. The emulsion has the characteristics of fast film formation speed, good water resistance, strong adhesion, fast drying speed, simple process, wide applicability, and ease of industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of functional polymer materials, and in particular to a nano-calcium carbonate modified polyacrylate emulsion and a preparation method thereof. Background Art

[0002] Nanoparticle / polymer composites have the advantages of both inorganic nanomaterials and functional polymers. They can combine the properties of inorganic, organic and nanoparticles. They are of great significance for the development of high-performance, special-functional composite materials and have shown good development and application prospects.

[0003] However, inorganic nanoparticles have poor interfacial adhesion to polymer matrices and are prone to agglomeration. Therefore, surface modification of nanoparticles to improve the interfacial adhesion between the particles and the matrix and their dispersibility is the key to achieving the reinforcement and toughening of polymer materials by nanoparticles. Nano calcium carbonate is an important functional inorganic filler that is widely used in the fields of plastics, rubber, coatings, and papermaking. Nano calcium carbonate is very prone to agglomeration due to its small particle size and high surface activity, making it difficult to disperse evenly in the matrix. At the same time, nano calcium carbonate is an inorganic hydrophilic compound with rich hydroxyl groups on its surface, which exhibits strong hydrophilic and oleophobic properties. Its hydrophilic and oleophobic properties result in poor affinity with the matrix during the filling process, making it easy to form agglomerates, resulting in uneven distribution in the matrix, and thus forming interface defects between the two phases. In order to fully exert the nano effect of nano calcium carbonate, improve the dispersibility of nanoparticles in polymers, and enhance the wettability and bonding strength of nanoparticles and polymers, nanoparticles must be surface treated. After surface modification, the surface energy of nano-calcium carbonate is reduced, the agglomeration phenomenon in the matrix is ​​reduced, the interface bonding force is improved, the compatibility with the matrix is ​​increased, and it has a better reinforcement effect.

[0004] Polyacrylate emulsions are often used as adhesives due to their excellent adhesion and cohesiveness. They can be used alone or with the addition of other additives to create adhesives with special features. Water-based polyacrylate emulsions are now widely used in the preparation of pressure-sensitive adhesives and heat-sealing adhesives for bonding wood, paper, and rubber. Water-based acrylic coatings are also widely used in the production of water-based inks due to their high transparency, adhesion, and gloss. Furthermore, polyacrylate emulsions have important applications in the textile, papermaking, automotive leather, and other industries.

[0005] However, existing polyacrylate emulsions have disadvantages such as poor water resistance, poor adhesion, slow film formation, brittleness at low temperatures, viscosity at high temperatures, poor stability, and easy bacterial growth under humid conditions. Summary of the Invention

[0006] The invention provides a nano-calcium carbonate modified polyacrylate emulsion and a preparation method thereof, which solves the problems of slow film-forming speed, poor water resistance and insufficient adhesion of the existing polyacrylate emulsion.

[0007] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0008] A nano-calcium carbonate modified polyacrylate emulsion is prepared from the following raw materials in parts by weight: 30-65 parts of acrylate mixed monomers, 8-30 parts of functional monomers, 0.1-1 part of modified nano-calcium carbonate emulsion, 1-5 parts of composite emulsifier, 0.08-0.65 parts of initiator, 2-4.5 parts of liquidambar resin, 0.02-0.2 parts of chain transfer agent, 0.1-5 parts of pH value regulator and 100-155 parts of deionized water.

[0009] The acrylic ester mixed monomer is a mixture of any two of ethyl acrylate, n-butyl acrylate, n-octyl acrylate, isooctyl acrylate and isobutyl methacrylate.

[0010] The functional monomer is composed of the following components in parts by weight: 2-8 parts of dimethylol propionic acid, 2-10 parts of acrylic acid and 4-12 parts of 1,6-hexanediol diacrylate.

[0011] The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 10-12 parts of nano-calcium carbonate, 40-45 parts of anhydrous ethanol, 40-45 parts of deionized water, 0.5-1.2 parts of acryloyloxyethyltrimethylammonium chloride, 0.2-0.6 parts of dispersant, and 0.1-0.5 parts of pH regulator.

[0012] The preparation method of the modified nano calcium carbonate emulsion comprises the following steps:

[0013] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0014] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 6.5-7.5 with 2% by mass sodium hydroxide solution, and emulsify with a disperser for 10 minutes to obtain modified nano-calcium carbonate emulsion.

[0015] The composite emulsifier is composed of a nonionic emulsifier and a reactive emulsifier in a mass ratio of 1:2.5; the nonionic emulsifier is alkylphenol polyoxyethylene ether, and the reactive emulsifier is any one of allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate, allyl polyethoxy sulfonate, sodium vinyl sulfonate and sodium allyl hydroxypropyl sulfonate;

[0016] The structural formula of allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate is as follows:

[0017]

[0018] Wherein, the initiator is potassium persulfate or ammonium persulfate.

[0019] Wherein, the chain transfer agent is ethylene glycol.

[0020] Wherein, the pH value regulator is a sodium hydroxide solution with a mass fraction of 2%.

[0021] A method for preparing a nano-calcium carbonate modified polyacrylate emulsion comprises the following steps:

[0022] (1) Add the initiator to 80-100 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0023] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 55-65°C and stir for 30 minutes;

[0024] (3) Heat to 80±2℃, add acrylate mixed monomer, functional monomer, modified nano calcium carbonate emulsion, sweet gum resin and chain transfer agent to the reaction bottle in sequence, add 70% initiator solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% initiator solution at one time, react for 90-120 minutes; then add the remaining 10% initiator solution at one time, heat to 88-90℃, and react for 60 minutes;

[0025] (4) Add a pH regulator to adjust the pH value of the reaction system to 3.8 ± 0.2, stir for 10 minutes, cool to room temperature, and discharge the product.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The modified nano-calcium carbonate emulsion is added during the preparation process of the polyacrylate emulsion of the present invention to improve the emulsion's adhesive strength, film-forming properties, water resistance, mechanical properties, and stability. The introduction of acryloyloxyethyltrimethylammonium chloride to surface-modify the nano-calcium carbonate effectively improves the dispersibility of the nano-calcium carbonate particles in the polymer emulsion and enhances the emulsion's stability and binding strength. Furthermore, as a quaternary ammonium salt, acryloyloxyethyltrimethylammonium chloride itself has bactericidal and antibacterial properties. Adding an excess of acryloyloxyethyltrimethylammonium chloride imparts excellent antibacterial and mildew-proof properties to the nano-calcium carbonate-modified polyacrylate emulsion, effectively resolving the problem of existing polyacrylate emulsions being susceptible to bacterial growth under humid conditions.

[0028] The OP-10 in the composite emulsifier of the present invention is a nonionic emulsifier that is easily soluble in water, acid and alkali resistant, has strong emulsification and good wetting power, penetration, hard water resistance, and antistatic properties. During the emulsion polymerization process, it adheres to the surface of the polymer emulsion particles by physical adsorption. The reactive emulsifiers, allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate, allyl polyethoxy sulfonate, sodium vinyl sulfonate, or sodium allyl hydroxypropyl sulfonate, contain both hydrophilic and lipophilic emulsifying groups in their molecular structure, as well as reactive groups such as double bonds, carboxyl groups, hydroxyl groups, and sulfonic acid groups. In addition to being used as an emulsifier during the polymerization reaction, it can also undergo copolymerization with acrylate monomers and functional monomers, permanently bonding to the polymer emulsion particles. This overcomes the problem of conventional emulsifiers remaining in the polymer, significantly improves the physical and chemical properties of the emulsion, and enhances the adhesion, water resistance, and stability of the emulsion.

[0029] Liquidambar resin in this invention is a newly developed natural resin, second only to rosin in natural reserves. It has similar tackifying properties to rosin and can be used as a new tackifying resin in the synthesis of polyacrylate emulsions to enhance the adhesive force of polymer emulsions, increase the initial viscosity of the emulsion, reduce the surface tension of the emulsion, and improve the wetting ability of the adherend. It also has significant environmental benefits.

[0030] The chain transfer agent in the present invention is ethylene glycol, which can effectively control the degree of polymerization (molecular weight) of the polymer, thereby controlling the viscosity of the emulsion and affecting the structure and properties of the emulsion.

[0031] The dispersant in this invention is readily soluble in water and can be miscible and mixed with various surfactants. It is acid-, alkali-, and hard water-resistant, and has excellent dispersibility and emulsification properties. It can effectively enhance the compatibility between components and improve the stability of the emulsion.

[0032] The nano-calcium carbonate-modified polyacrylate emulsion of the present invention can be used as water-based paint, water-based ink, environmentally friendly adhesive, textile printing and dyeing, leather finishing, building cement mortar, and as a functional material in other fields. It has the characteristics of fast film-forming speed, good water resistance, strong adhesion, fast drying speed, simple process, wide applicability, and easy industrial production. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] In the following examples, the dispersant is dispersant IW purchased from Haian Petrochemical Plant in Jiangsu Province, and its chemical composition is a condensate of fatty alcohol and ethylene oxide.

[0035] Example 1

[0036] The invention provides a nano-calcium carbonate modified polyacrylate emulsion, which is prepared from the following raw materials in parts by weight: 35 parts of ethyl acrylate, 25 parts of n-butyl acrylate, 8 parts of dimethylolpropionic acid, 10 parts of acrylic acid, 8 parts of 1,6-hexanediol diacrylate, 0.5 part of modified nano-calcium carbonate emulsion, 3 parts of a composite emulsifier, 0.32 parts of potassium persulfate, 2.5 parts of liquidambar resin, 0.2 parts of ethylene glycol, 2.5 parts of a sodium hydroxide solution with a mass fraction of 2%, and 105 parts of deionized water.

[0037] The composite emulsifier is composed of alkylphenol polyoxyethylene ether (OP-10) and allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate (DNS-86) in a mass ratio of 1:2.5;

[0038] The modified nano-calcium carbonate emulsion is prepared from the following raw materials: nano-calcium carbonate, anhydrous ethanol, acryloyloxyethyl trimethyl ammonium chloride, deionized water, a dispersant and a pH regulator.

[0039] The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 11 parts nano-calcium carbonate, 42 parts anhydrous ethanol, 42 parts deionized water, 0.8 parts acryloyloxyethyl trimethyl ammonium chloride, 0.4 parts dispersant, and 0.2 parts pH regulator. The preparation method of the modified nano-calcium carbonate emulsion includes the following steps:

[0040] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0041] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 7.2 with 2% by mass sodium hydroxide solution, and emulsify with an ANN AD500S-H dispersing homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion.

[0042] This embodiment also provides a method for preparing the above-mentioned nano-calcium carbonate modified polyacrylate emulsion, comprising the following steps:

[0043] (1) Add potassium persulfate to 90 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0044] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 60°C and stir for 30 minutes;

[0045] (3) Heat to 80±2°C, add ethyl acrylate, n-butyl acrylate, functional monomer, modified nano-calcium carbonate emulsion, sweet gum resin and ethylene glycol to the reaction flask in sequence, add 70% potassium persulfate solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% potassium persulfate solution at one time and react for 100 minutes; then add the remaining 10% potassium persulfate solution at one time, heat to 88-90°C and react for 60 minutes;

[0046] (4) Add 2% by mass of sodium hydroxide solution, adjust the pH value of the reaction system to 3.9, stir for 10 minutes, cool to room temperature, and discharge the product.

[0047] Example 2

[0048] The invention provides a nano-calcium carbonate modified polyacrylate emulsion, which is prepared from the following raw materials in parts by weight: 45 parts of n-octyl acrylate, 15 parts of isooctyl acrylate, 8 parts of dimethylol propionic acid, 7 parts of acrylic acid, 12 parts of 1,6-hexanediol diacrylate, 0.7 parts of modified nano-calcium carbonate emulsion, 5 parts of a composite emulsifier, 0.38 parts of potassium persulfate, 4.5 parts of liquidambar resin, 0.15 parts of ethylene glycol, 5 parts of a sodium hydroxide solution with a mass fraction of 2%, and 100 parts of deionized water.

[0049] The composite emulsifier is composed of alkylphenol polyoxyethylene ether (OP-10) and allyl polyethoxy sulfonate (SE-10N) in a mass ratio of 1:2.5.

[0050] The modified nano-calcium carbonate emulsion is made from the following raw materials in parts by weight: 10 parts nano-calcium carbonate, 45 parts anhydrous ethanol, 40 parts deionized water, 1.2 parts acryloyloxyethyl trimethyl ammonium chloride, 0.2 parts dispersant, and 0.1 parts pH regulator. The preparation method of the modified nano-calcium carbonate emulsion includes the following steps:

[0051] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0052] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 6.8 with 2% by mass sodium hydroxide solution, and emulsify with an ANN AD500S-H dispersing homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion.

[0053] This embodiment also provides a method for preparing the above-mentioned nano-calcium carbonate modified polyacrylate emulsion, comprising the following steps:

[0054] (1) Add potassium persulfate to 80 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0055] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 65°C and stir for 30 minutes;

[0056] (3) Heat to 80±2°C, add n-octyl acrylate, isooctyl acrylate, functional monomer, modified nano-calcium carbonate emulsion, sweet gum resin and ethylene glycol to the reaction flask in sequence, add 70% potassium persulfate solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% potassium persulfate solution at one time and react for 90 minutes; then add the remaining 10% potassium persulfate solution at one time, heat to 88-90°C and react for 60 minutes;

[0057] (4) Add 2% by mass of sodium hydroxide solution, adjust the pH value of the reaction system to 4.0, stir for 10 minutes, cool to room temperature, and discharge the material.

[0058] Example 3

[0059] The invention provides a nano-calcium carbonate modified polyacrylate emulsion, which is prepared from the following raw materials in parts by weight: 30 parts of isooctyl acrylate, 35 parts of isobutyl methacrylate, 2 parts of dimethylol propionic acid, 10 parts of acrylic acid, 12 parts of 1,6-hexanediol diacrylate, 1 part of modified nano-calcium carbonate emulsion, 1 part of a composite emulsifier, 0.65 parts of ammonium persulfate, 2 parts of liquidambar resin, 0.2 parts of ethylene glycol, 0.1 part of a sodium hydroxide solution with a mass fraction of 2%, and 110 parts of deionized water.

[0060] The composite emulsifier is composed of alkylphenol polyoxyethylene ether (OP-10) and sodium vinyl sulfonate (SVS) in a mass ratio of 1:2.5.

[0061] The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 12 parts nano-calcium carbonate, 40 parts anhydrous ethanol, 45 parts deionized water, 0.5 parts acryloyloxyethyl trimethyl ammonium chloride, 0.6 parts dispersant, and 0.3 parts pH regulator. The preparation method of the modified nano-calcium carbonate emulsion includes the following steps:

[0062] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0063] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 7.5 with 2% by mass sodium hydroxide solution, and emulsify with an ANN AD500S-H dispersing homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion.

[0064] This embodiment also provides a method for preparing the above-mentioned nano-calcium carbonate modified polyacrylate emulsion, comprising the following steps:

[0065] (1) Add ammonium persulfate to 100 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0066] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 55°C and stir for 30 minutes;

[0067] (3) Heat to 80±2°C, add isooctyl acrylate, isobutyl methacrylate, functional monomer, modified nano calcium carbonate emulsion, liquidammonia resin and ethylene glycol to the reaction flask in sequence, add 70% ammonium persulfate solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% ammonium persulfate solution at one time, react for 120 minutes; then add the remaining 10% ammonium persulfate solution at one time, heat to 88-90°C, and react for 60 minutes;

[0068] (4) Add 2% by mass of sodium hydroxide solution, adjust the pH value of the reaction system to 3.7, stir for 10 minutes, cool to room temperature, and discharge the product.

[0069] Example 4

[0070] The invention provides a nano-calcium carbonate modified polyacrylate emulsion, which is prepared from the following raw materials in parts by weight: 25 parts of ethyl acrylate, 40 parts of isooctyl acrylate, 7 parts of dimethylolpropionic acid, 9 parts of acrylic acid, 12 parts of 1,6-hexanediol diacrylate, 0.8 parts of modified nano-calcium carbonate emulsion, 4.5 parts of a composite emulsifier, 0.45 parts of ammonium persulfate, 4.0 parts of liquidambar resin, 0.15 parts of ethylene glycol, 0.2 parts of a sodium hydroxide solution with a mass fraction of 2%, and 125 parts of deionized water.

[0071] The composite emulsifier is composed of alkylphenol polyoxyethylene ether (OP-10) and sodium allyl hydroxypropyl sulfonate (COPS-1) in a mass ratio of 1:2.5.

[0072] The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 10 parts nano-calcium carbonate, 41 parts anhydrous ethanol, 44 parts deionized water, 0.6 parts acryloyloxyethyltrimethylammonium chloride, 0.5 parts dispersant, and 0.2 parts pH regulator. The preparation method of the modified nano-calcium carbonate emulsion includes the following steps:

[0073] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0074] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 7.4 with 2% by mass sodium hydroxide solution, and emulsify with an ANN AD500S-H dispersing homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion.

[0075] This embodiment also provides a method for preparing the above-mentioned nano-calcium carbonate modified polyacrylate emulsion, comprising the following steps:

[0076] (1) Add ammonium persulfate to 90 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0077] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 60°C and stir for 30 minutes;

[0078] (3) Heat to 80±2°C, add ethyl acrylate, isooctyl acrylate, functional monomer, modified nano calcium carbonate emulsion, liquidammonia resin and ethylene glycol to the reaction flask in sequence, add 70% ammonium persulfate solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% ammonium persulfate solution at one time, react for 105 minutes; then add the remaining 10% ammonium persulfate solution at one time, heat to 88-90°C, and react for 60 minutes;

[0079] (4) Add 2% by mass of sodium hydroxide solution, adjust the pH value of the reaction system to 3.6, stir for 10 minutes, cool to room temperature, and discharge the product.

[0080] Example 5

[0081] The invention provides a nano-calcium carbonate modified polyacrylate emulsion, which is prepared from the following raw materials in parts by weight: 30 parts of n-butyl acrylate, 30 parts of n-octyl acrylate, 6 parts of dimethylol propionic acid, 10 parts of acrylic acid, 10 parts of 1,6-hexanediol diacrylate, 0.8 parts of modified nano-calcium carbonate emulsion, 4 parts of a composite emulsifier, 0.5 parts of potassium persulfate, 3.5 parts of liquidambar resin, 0.08 parts of ethylene glycol, 1.1 parts of a sodium hydroxide solution with a mass fraction of 2%, and 110 parts of deionized water.

[0082] The composite emulsifier is composed of alkylphenol polyoxyethylene ether (OP-10) and allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate (DNS-86) in a mass ratio of 1:2.5.

[0083] The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 11 parts nano-calcium carbonate, 44 parts anhydrous ethanol, 42 parts deionized water, 1.0 part acryloyloxyethyl trimethyl ammonium chloride, 0.5 part dispersant, and 0.5 part pH regulator. The preparation method of the modified nano-calcium carbonate emulsion includes the following steps:

[0084] (1) Place nano-calcium carbonate and anhydrous ethanol in a single-necked flask and ultrasonically emulsify for 30 minutes. Place the mixture in a three-necked flask with stirring, add acryloyloxyethyl trimethyl ammonium chloride, and ultrasonically emulsify for 15 minutes. Heat the mixture to 80±2°C and ultrasonicate for 2 hours. Pour out the suspension, filter, and wash. Place the filter cake in a vacuum oven at 105°C and dry it for 2 hours to obtain modified nano-calcium carbonate.

[0085] (2) Add modified nano-calcium carbonate, deionized water and dispersant into a beaker, adjust the pH value to 7.0 with 2% by mass sodium hydroxide solution, and emulsify with an ANN AD500S-H dispersing homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion.

[0086] This embodiment also provides a method for preparing the above-mentioned nano-calcium carbonate modified polyacrylate emulsion, comprising the following steps:

[0087] (1) Add potassium persulfate to 90 times the amount of deionized water and stir evenly to obtain an initiator solution;

[0088] (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask, control the temperature at 60°C and stir for 30 minutes;

[0089] (3) Heat to 80±2°C, add n-butyl acrylate, n-octyl acrylate, functional monomer, modified nano-calcium carbonate emulsion, sweet gum resin and ethylene glycol to the reaction flask in sequence, add 70% potassium persulfate solution dropwise within 60 minutes, keep warm and react for 60 minutes; add 20% potassium persulfate solution at one time, react for 110 minutes; then add the remaining 10% potassium persulfate solution at one time, heat to 88-90°C, and react for 60 minutes;

[0090] (4) Add 2% by mass of sodium hydroxide solution, adjust the pH value of the reaction system to 3.8, stir for 10 minutes, cool to room temperature, and discharge the product.

[0091] Comparative Example 1

[0092] The emulsifier used in this embodiment is alkylphenol polyoxyethylene ether (OP-10), and the other components are the same as those in Example 1 and will not be described in detail here.

[0093] Comparative Example 2

[0094] This embodiment does not add the modified nano calcium carbonate emulsion, and the rest is the same as that of Example 1, which will not be repeated here.

[0095] Performance Testing

[0096] The performance tests were performed on the nano-calcium carbonate modified polyacrylate emulsions prepared in Examples 1-5, Comparative Example 1 and Comparative Example 2.

[0097] For the emulsion water resistance test, apply an appropriate amount of adhesive to the label and adhere it to a beer bottle. After drying 20 labeled beer bottles at room temperature for 48 hours, place them in an ice-water mixture. Rotate the bottles every two hours and record the time it takes for each label to fall off. The time it takes for the tenth label to fall off is the adhesive's water resistance.

[0098] Emulsion stability test: Weigh 400g of sample into a 500mL beaker and test the sample viscosity every 24 hours at room temperature for 60 consecutive days. If the viscosity value changes by less than 2%, it is considered stable; if the viscosity value changes by more than 2%, it is considered unstable. The test results are as follows:

[0099] Table 1 Appearance, solid content, monomer conversion rate and viscosity test results

[0100] Polyacrylate emulsion Appearance Solid content / % Monomer conversion rate / % Viscosity / (mPa·s,25℃) Example 1 Milky white uniform (bluish) 46.0 98.6 1750 Example 2 Milky white uniform (bluish) 47.9 98.7 1710 Example 3 Milky white uniform (bluish) 45.6 98.1 1590 Example 4 Milky white uniform (bluish) 44.8 98.8 1680 Example 5 Milky white uniform (bluish) 45.7 98.6 1650 Comparative Example 1 Milky white uniform (bluish) 45.5 91.5 840 Comparative Example 2 Milky white uniform (with blue light) 44.8 98.2 1020

[0101] Table 2 Minimum film forming temperature, water resistance and stability test results

[0102] Although the embodiments of the present invention have been described above, it will be apparent to those skilled in the art that modifications and substitutions made without departing from the principles and spirit of the present invention are intended to fall within the scope of protection claimed by the present invention.

Claims

1. A nano calcium carbonate modified polyacrylate emulsion, characterized in that The invention is prepared from the following raw materials in parts by weight: 30-65 parts of acrylate mixed monomer, 8-30 parts of functional monomer, 0.1-1 part of modified nano calcium carbonate emulsion, 1-5 parts of composite emulsifier, 0.08-0.65 parts of initiator, 2-4.5 parts of liquidambar resin, 0.02-0.2 parts of chain transfer agent, 0.1-5 parts of pH value regulator and 100-155 parts of deionized water. The modified nano-calcium carbonate emulsion is prepared from the following raw materials in parts by weight: 10-12 parts of nano-calcium carbonate, 40-45 parts of anhydrous ethanol, 40-45 parts of deionized water, 0.5-1.2 parts of acryloyloxyethyltrimethylammonium chloride, 0.2-0.6 parts of a dispersant, and 0.1-0.5 parts of a pH regulator; The preparation method of the modified nano calcium carbonate emulsion comprises the following steps: (1) Nano-calcium carbonate and anhydrous ethanol were placed in a single-necked flask and ultrasonically emulsified for 30 minutes. The mixture was placed in a three-necked flask with stirring, and acryloyloxyethyl trimethyl ammonium chloride was added and ultrasonically emulsified for 15 minutes. The mixture was heated to 80±2°C and ultrasonicated for 2 hours. The suspension was poured out, filtered, and washed. The filter cake was placed in a vacuum oven at 105°C and dried for 2 hours to obtain modified nano-calcium carbonate. (2) adding modified nano-calcium carbonate, deionized water, and a dispersant into a beaker, adjusting the pH value to 6.5-7.5 with a 2% sodium hydroxide solution, and emulsifying the mixture with a homogenizer for 10 minutes to obtain a modified nano-calcium carbonate emulsion; The composite emulsifier is composed of a nonionic emulsifier and a reactive emulsifier in a mass ratio of 1:2.5; the nonionic emulsifier is alkylphenol polyoxyethylene ether, and the reactive emulsifier is any one of allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate, allyl polyethoxy sulfonate, sodium vinyl sulfonate and sodium allyl hydroxypropyl sulfonate; The structural formula of allyloxy nonylphenol polyoxyethylene (10) ether ammonium sulfate is as follows: The chain transfer agent is ethylene glycol.

2. A nano-calcium carbonate modified polyacrylate emulsion according to claim 1, characterized in that: The acrylic acid ester mixed monomer is a mixture of any two of ethyl acrylate, n-butyl acrylate, n-octyl acrylate, isooctyl acrylate and isobutyl methacrylate.

3. A nano calcium carbonate modified polyacrylate emulsion according to claim 1, characterized in that The functional monomer is composed of the following components in parts by weight: 2-8 parts of dimethylol propionic acid, 2-10 parts of acrylic acid and 4-12 parts of 1,6-hexanediol diacrylate.

4. The nano-calcium carbonate modified polyacrylate emulsion according to claim 1, wherein: The initiator is potassium persulfate or ammonium persulfate.

5. The nano-calcium carbonate modified polyacrylate emulsion according to claim 1, characterized in that: The pH value regulator is a sodium hydroxide solution with a mass fraction of 2%.

6. A method for preparing the nano-calcium carbonate modified polyacrylate emulsion according to any one of claims 1 to 5, characterized in that The steps include: (1) Add the initiator to 80-100 times the amount of deionized water and stir evenly to obtain an initiator solution; (2) Add the remaining deionized water and composite emulsifier into a four-necked reaction flask and stir at 55-65°C for 30 minutes; (3) Raise the temperature to 80±2°C, add the acrylic ester mixed monomer, functional monomer, modified nano-calcium carbonate emulsion, liquidambar resin and chain transfer agent to the reaction flask in sequence, add 70% of the initiator solution dropwise over 60 minutes, and keep warm for 60 minutes; add 20% of the initiator solution at once and react for 90-120 minutes; then add the remaining 10% of the initiator solution at once, raise the temperature to 88-90°C, and react for 60 minutes; (4) Add a pH regulator to adjust the pH value of the reaction system to 3.8±0.2, stir for 10 minutes, cool to room temperature, and discharge the product.

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