Rosin modified acrylic emulsion, preparation method thereof and adhesive

Abstract

The invention provides a rosin modified acrylic emulsion, a preparation method thereof and an adhesive, and belongs to the technical field of pressure-sensitive adhesives. The modified rosin in the high-solid-content low-viscosity rosin modified acrylic emulsion provided by the invention forms a solubilizing effect in the preparation process, and is matched with the rosin resin emulsion, so that the rosin resin emulsion has a better binding power increasing effect; the functional monomer is added, so that the emulsion can maintain better permanent adhesion and reduce the surface tension of the emulsion while having high initial adhesion; protective colloid is added to improve the stability of an emulsion system; by adding the hard monomer, the cohesion of the emulsion can be remarkably improved, and the permanent adhesion of the emulsion is improved; the composition of the rosin modified acrylic emulsion and the use amount of each component are controlled, so that the adhesive prepared from the rosin modified acrylic emulsion has better initial adhesion and permanent adhesion.

Description

Technical Field

[0001] The invention relates to the technical field of pressure-sensitive adhesives, in particular to a rosin-modified acrylic emulsion and a preparation method thereof and an adhesive. Background Art

[0002] Self-adhesive paper labels (coated paper or thermal paper, etc.) are widely used in various industries such as food, medicine, daily chemicals, supermarkets, daily life, etc. They are widely used and used in huge quantities. Curtain coating, as a new coating method, has the advantages of fast coating speed, high production efficiency, and low coating cost. It is a better large-scale coating method. The current paper curtain coating self-adhesive adhesive mainly uses high-solid content, low-viscosity acrylic emulsion with rosin resin emulsion and wetting agent to adjust the mechanical properties and coating properties, but there are mechanical problems such as low initial adhesion or low lasting adhesion during use. Therefore, there is an urgent need for an acrylic emulsion so that the adhesive prepared therefrom has high initial adhesion and high lasting adhesion. Summary of the invention

[0003] The purpose of the present invention is to provide a rosin-modified acrylic emulsion and a preparation method thereof and an adhesive. The adhesive prepared from the rosin-modified acrylic emulsion provided by the present invention has excellent initial adhesion and sustained adhesion.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The invention provides a rosin modified acrylic emulsion, which comprises the following raw materials in parts by weight: 50-56 parts of soft monomers, 5-10 parts of hard monomers, 1.95-5 parts of functional monomers, 1-5 parts of modified rosin, 0.02-0.06 parts of molecular weight regulators, 2-5 parts of emulsifiers, 0.01-0.1 parts of protective colloids, 0.02-0.1 parts of pH buffers, 0.2-0.6 parts of initiators, 0.01-0.1 parts of oxidants, 0.01-0.1 parts of reducing agents, 0.01-1 parts of pH regulators, 0.05-0.5 parts of preservatives and 30-40 parts of water.

[0006] Preferably, the soft monomer includes one or more of n-butyl acrylate, isooctyl acrylate and ethyl acrylate.

[0007] Preferably, the hard monomer includes one or more of methyl methacrylate, styrene and vinyl versatate.

[0008] Preferably, the functional monomer includes one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and β-acryloxypropionic acid.

[0009] Preferably, the molecular weight regulator includes one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol and thioglycolic acid.

[0010] Preferably, the protective colloid comprises one or more of sodium polyacrylate, sodium polymethacrylate, sodium tripolyphosphate, gum arabic, polyethylene oxide and hydroxymethyl cellulose.

[0011] Preferably, the modified rosin includes one or more of hydrogenated rosin and hydrogenated rosin glycerol ester.

[0012] Preferably, the emulsifier includes one or more of sodium acrylamido-2-methylpropane sulfonate, sodium vinyl sulfonate, allyl polyether sulfate, fatty alcohol polyoxyethylene ether and alkenyl polyoxyethylene ether.

[0013] The present invention also provides a method for preparing the rosin-modified acrylic emulsion described in the above technical solution, comprising the following steps:

[0014] (1) mixing part of the initiator with the first part of water to obtain a primer initiator; mixing the remaining initiator with the second part of water to obtain a drop initiator; mixing part of the emulsifier with the third part of water to obtain a secondary bundled emulsifier; mixing the oxidant with the fourth part of water to obtain an oxidant solution; mixing the reducing agent with the fifth part of water to obtain a reducing agent solution; mixing the modified rosin with part of the soft monomer to obtain a modified rosin solution;

[0015] (2) mixing the sixth portion of water, the pH buffer, the molecular weight regulator, the remaining emulsifier, the modified rosin solution obtained in step (1), the remaining soft monomer, the hard monomer and the functional monomer, and pre-emulsifying the mixture to obtain a pre-emulsified solution;

[0016] (3) mixing the seventh portion of water, the protective colloid, the priming initiator obtained in step (1), the pre-emulsion obtained in step (2), the dropping initiator obtained in step (1), and the secondary bunching emulsifier obtained in step (1), and performing a polymerization reaction to obtain an emulsion;

[0017] (4) The emulsion obtained in step (3) is mixed with a part of the pH adjuster and the remaining water, and the oxidant solution obtained in step (1), the reducing agent solution obtained in step (1), the remaining pH adjuster and the preservative are added in sequence for post-treatment to obtain a rosin-modified acrylic emulsion.

[0018] The present invention also provides an adhesive, which comprises, by weight, 70-79 parts of the rosin-modified acrylic emulsion described in the above technical solution or the rosin-modified acrylic emulsion prepared by the preparation method described in the above technical solution, 20-29 parts of rosin resin emulsion and 0.3-0.5 parts of a wetting agent.

[0019] The invention provides a rosin modified acrylic emulsion, which comprises the following raw materials in parts by weight: 50-56 parts of soft monomers, 5-10 parts of hard monomers, 1.95-5 parts of functional monomers, 1-5 parts of modified rosin, 0.02-0.06 parts of molecular weight regulators, 2-5 parts of emulsifiers, 0.01-0.1 parts of protective colloids, 0.02-0.1 parts of pH buffers, 0.2-0.6 parts of initiators, 0.01-0.1 parts of oxidants, 0.01-0.1 parts of reducing agents, 0.01-1 parts of pH regulators, 0.05-0.5 parts of preservatives and 30-40 parts of water. The modified rosin in the rosin-modified acrylic emulsion provided by the present invention forms a solubilizing effect during the preparation process, and the modified rosin is introduced into the emulsion core-shell structure to form an island structure as the monomer is synthesized, and has better compatibility with the rosin resin emulsion when mixed, and can better form the island structure of the rosin resin emulsion after mixing, reduce the enrichment of rosin resin during the compounding of traditional rosin resin emulsion, and make the rosin resin emulsion have a better effect of increasing the bonding force; the addition of functional monomers makes the emulsion core-shell surface have more hydroxyl and carboxyl polar functional groups, so that the emulsion has better adsorption and wettability to the adherend, and at the same glass transition temperature, the emulsion can maintain better holding force and lowering force while having high initial adhesion. Low surface tension of the emulsion; adding protective colloid, part of which is adsorbed on the surface of the core-shell structure of the emulsion, and part of which is dissolved in the water phase. The adsorbed protective colloid forms a hydration layer of a certain thickness on the surface of the emulsion particles, which can hinder the collision of latex particles and cause polymerization; the protective colloid dissolved in the water phase can increase the viscosity of the polymer emulsion, increase the resistance of the collision of latex particles, so adding protective colloid can improve the stability of the emulsion system and improve its curtain-forming property; adding hard monomers can significantly improve the cohesive force of the emulsion and improve the holding force of the emulsion; controlling the composition of the rosin-modified acrylic emulsion and the amount of each component, so that the adhesive prepared by the rosin-modified acrylic emulsion has better initial adhesion and holding force. The results of the embodiment show that the annular initial adhesion of the adhesive prepared by the rosin-modified acrylic emulsion provided by the present invention is above 19N / 25mm, the peeling force is above 10N / 25mm, the holding force is above 16h, the 10℃ PE initial adhesion is above 9N / 25mm, and the curtain-forming condition is good. DETAILED DESCRIPTION

[0020] The invention provides a rosin modified acrylic emulsion, which comprises the following raw materials in parts by weight: 50-56 parts of soft monomers, 5-10 parts of hard monomers, 1.95-5 parts of functional monomers, 1-5 parts of modified rosin, 0.02-0.06 parts of molecular weight regulators, 2-5 parts of emulsifiers, 0.01-0.1 parts of protective colloids, 0.02-0.1 parts of pH buffers, 0.2-0.6 parts of initiators, 0.01-0.1 parts of oxidants, 0.01-0.1 parts of reducing agents, 0.01-1 parts of pH regulators, 0.05-0.5 parts of preservatives and 30-40 parts of water.

[0021] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0022] By weight, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 50 to 56 parts of soft monomers, preferably 51 to 55 parts, and more preferably 52 to 54 parts.

[0023] In the present invention, the soft monomer preferably includes one or more of n-butyl acrylate, isooctyl acrylate and ethyl acrylate, and more preferably includes n-butyl acrylate and isooctyl acrylate. When the soft monomer includes n-butyl acrylate and isooctyl acrylate, the mass ratio of n-butyl acrylate to isooctyl acrylate is preferably (25-26): (26-27), and more preferably 25.35:26.652. In the present invention, the soft monomer provides pressure sensitivity for the emulsion. The present invention limits the amount and type of the soft monomer to the above range, so that the emulsion has better pressure sensitivity.

[0024] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 5 to 10 parts by weight of the hard monomer, preferably 6 to 9 parts by weight, and more preferably 7 to 9 parts by weight.

[0025] In the present invention, the hard monomer preferably includes one or more of methyl methacrylate, styrene and versatate vinyl carbonate; more preferably includes methyl methacrylate and versatate vinyl carbonate. When the hard monomer includes methyl methacrylate and versatate vinyl carbonate, the mass ratio of methyl methacrylate to versatate vinyl carbonate is preferably (3.2-5.2):2.6, more preferably (4.2-5.2):2.6.

[0026] In the present invention, the hard monomer provides cohesive strength for the emulsion. The present invention limits the amount and type of the hard monomer to the above range, and the addition of versatate vinyl carbonate can significantly improve the cohesive force of the emulsion. At the same time, the glass transition temperature of versatate vinyl carbonate is -3°C. Under the condition of the same glass transition temperature of the emulsion, more hard monomers can be added to improve the cohesive force and the lasting adhesion of the emulsion, thereby improving the initial adhesion and the lasting adhesion of the adhesive prepared therefrom.

[0027] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 1.95 to 5 parts of the functional monomer, preferably 2 to 5 parts, and more preferably 3 to 5 parts.

[0028] In the present invention, the functional monomer preferably includes one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and β-acryloxypropionic acid; more preferably includes methacrylic acid, hydroxyethyl methacrylate and β-acryloxypropionic acid. When the functional monomer includes methacrylic acid, hydroxyethyl methacrylate and β-acryloxypropionic acid, the mass ratio of methacrylic acid, hydroxyethyl methacrylate and β-acryloxypropionic acid is preferably (0.78-2): (0.78-2): 0.39, more preferably (1-1.5): (1-1.5): 0.39.

[0029] In the present invention, the addition of the functional monomer allows the core-shell surface of the emulsion to have more hydroxyl and carboxyl polar functional groups, so that the emulsion has better adsorption and wettability to the adherend, and at the same glass transition temperature, the emulsion can maintain better persistent adhesion and reduce the surface tension of the emulsion while having high initial adhesion. The present invention limits the amount and type of the functional monomer to the above range, which can further improve the initial adhesion and persistent adhesion of the adhesive prepared from the emulsion, while reducing the surface tension of the emulsion, and better curtain formation when curtain coating is adopted.

[0030] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 1 to 5 parts of modified rosin, preferably 2 to 4 parts.

[0031] In the present invention, the modified rosin preferably includes one or more of hydrogenated rosin and hydrogenated rosin glycerol ester.

[0032] In the present invention, the modified rosin forms a solubilizing effect during the preparation process, and the modified rosin is introduced into the emulsion core-shell structure to form an island structure as the monomer is synthesized, and has better compatibility with the rosin resin emulsion, and can better form the island structure of the rosin resin emulsion after the mutual mixing, reduce the enrichment of rosin resin when the traditional rosin resin emulsion is compounded, and make the rosin resin emulsion have a better effect of increasing the bonding force. The present invention limits the amount and type of modified rosin within the above range, which can further improve the initial adhesion and the lasting adhesion of the adhesive prepared by the emulsion.

[0033] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.02 to 0.06 parts by weight of a molecular weight regulator, preferably 0.03 to 0.04 parts by weight.

[0034] In the present invention, the molecular weight regulator preferably includes one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol and thioglycolic acid.

[0035] In the present invention, the molecular weight regulator is used to control the molecular weight of the emulsion. The present invention limits the amount and type of the molecular weight regulator to the above range, which can make the emulsion have a suitable molecular weight and further improve the initial adhesion, lasting adhesion and curtain formation of the adhesive.

[0036] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 2 to 5 parts by weight of an emulsifier, preferably 3 to 4 parts by weight.

[0037] In the present invention, the emulsifier preferably includes one or more of sodium acrylamido-2-methylpropane sulfonate, sodium vinyl sulfonate, allyl polyether sulfate, fatty alcohol polyoxyethylene ether and alkenyl polyoxyethylene ether, and more preferably includes allyl polyether sulfate and fatty alcohol polyoxyethylene ether. When the emulsifier includes allyl polyether sulfate and fatty alcohol polyoxyethylene ether, the mass ratio of the allyl polyether sulfate and the fatty alcohol polyoxyethylene ether is preferably (2.5-3):0.26, more preferably 2.99:0.26.

[0038] In the present invention, the emulsifier is used to emulsify the monomer and provide a reaction environment. The present invention limits the amount and type of the emulsifier to the above range, the allyl polyether sulfate anionic emulsifier improves the cohesion and chemical stability of the emulsion, and the fatty alcohol polyoxyethylene ether nonionic emulsifier improves the mechanical stability and adhesion of the emulsion, which can further improve the initial adhesion, lasting adhesion and curtain formation of the adhesive.

[0039] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.01 to 0.1 parts of protective colloid, preferably 0.02 to 0.08 parts.

[0040] In the present invention, the protective colloid preferably includes one or more of sodium polyacrylate, sodium polymethacrylate, sodium tripolyphosphate, gum arabic, polyethylene oxide and hydroxymethyl cellulose.

[0041] In the present invention, part of the protective colloid is adsorbed on the surface of the core-shell structure of the emulsion, and part of it is dissolved in the aqueous phase. The adsorbed protective colloid forms a hydration layer of a certain thickness on the surface of the emulsion particles, which can hinder the collision and aggregation of the latex particles; the protective colloid dissolved in the aqueous phase can increase the viscosity of the polymer emulsion and increase the resistance to the collision of the latex particles. Therefore, adding the protective colloid can improve the stability of the emulsion system, make the emulsion discharge less slag, and make the reaction more stable, which is conducive to large-scale production; at the same time, it improves the curtain-forming property of the adhesive. The present invention limits the amount and type of the protective colloid to the above range, which can make the reaction more stable, reduce the emulsion discharge slag, and the adhesive has better curtain-forming property.

[0042] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.02 to 0.1 parts of pH buffer, preferably 0.03 to 0.08 parts.

[0043] In the present invention, the pH buffer preferably includes one or more of sodium bicarbonate, ammonium bicarbonate, sodium carbonate, ammonium carbonate, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, potassium bicarbonate and potassium carbonate.

[0044] In the present invention, the pH buffer provides a suitable pH value for the reaction. The present invention limits the amount and type of the pH buffer to the above range, which can make the emulsion have a suitable pH value during synthesis and is conducive to the formation of the emulsion.

[0045] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.2 to 0.6 parts by weight of the initiator, preferably 0.3 to 0.5 parts by weight.

[0046] In the present invention, the initiator preferably includes one or more of potassium persulfate, ammonium persulfate and sodium persulfate.

[0047] In the present invention, the initiator is used to initiate the reaction of the monomers. The present invention limits the amount and type of the initiator to the above range, so that each raw material can react fully and have a suitable reaction rate.

[0048] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.01 to 0.1 parts by weight of an oxidant, preferably 0.02 to 0.08 parts by weight.

[0049] In the present invention, the oxidant preferably includes one or more of tert-butyl hydroperoxide and hydrogen peroxide.

[0050] In the present invention, the oxidant is used to remove the monomers remaining from the reaction and reduce the odor and VOC of the emulsion. The present invention limits the amount and type of the oxidant to the above range, which can fully remove the monomers remaining from the reaction.

[0051] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.01 to 0.1 parts of reducing agent, preferably 0.02 to 0.08 parts.

[0052] In the present invention, the reducing agent preferably includes one or more of sodium sulfite, sodium bisulfite, sodium formaldehyde sulfoxylate and sodium isoascorbate.

[0053] In the present invention, the reducing agent is used to remove the residual oxidant. The present invention limits the amount and type of the reducing agent to the above range, so that the oxidant can be fully removed.

[0054] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.01 to 1 part of a pH regulator, preferably 0.1 to 0.8 part.

[0055] In the present invention, the pH regulator preferably includes one or more of ammonia water, sodium hydroxide, potassium hydroxide and triethanolamine. In the present invention, the mass concentration of ammonia water is preferably 22-26%, more preferably 25%.

[0056] In the present invention, the pH regulator is used to adjust the pH value of the emulsion and improve the storage stability of the emulsion. The present invention limits the amount and type of the pH regulator to the above range, which can make the emulsion have a suitable pH value and further improve its storage stability.

[0057] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 0.05 to 0.5 parts by weight of the preservative, preferably 0.05 to 0.4 parts by weight.

[0058] In the present invention, the preservative preferably includes one or more of a kasone preservative and a 1,2-benzisothiazolin-3-one preservative. In the present invention, the preservative is used to improve the antiseptic property of the emulsion. The present invention limits the amount and type of the preservative to the above range, which can further improve the antiseptic property of the emulsion.

[0059] Based on 50 to 56 parts by weight of the soft monomer, the raw materials for preparing the rosin-modified acrylic emulsion of the present invention include 30 to 40 parts of water, preferably 32 to 38 parts.

[0060] In the present invention, the water is preferably deionized water. The present invention limits the amount of water to the above range, which can make the emulsion have a suitable solid content and viscosity, and further improve the initial adhesion, lasting adhesion and curtain forming condition of the adhesive prepared therefrom.

[0061] In the present invention, the solid content of the rosin-modified acrylic emulsion is preferably 63-65%; the viscosity of the rosin-modified acrylic emulsion is preferably 210-460 CPS; the pH value of the rosin-modified acrylic emulsion is preferably 6-7, more preferably 6.5; the surface tension of the rosin-modified acrylic emulsion is preferably 38-42 mN / m.

[0062] The invention controls the composition of the rosin modified acrylic emulsion and the amount of each component, so that the adhesive prepared by the rosin modified acrylic emulsion has better initial adhesion and lasting adhesion, and has excellent curtain-forming property when curtain coating is adopted.

[0063] The present invention also provides a method for preparing the rosin-modified acrylic emulsion described in the above technical solution, comprising the following steps:

[0064] (1) mixing part of the initiator with the first part of water to obtain a primer initiator; mixing the remaining initiator with the second part of water to obtain a drop initiator; mixing part of the emulsifier with the third part of water to obtain a secondary bundled emulsifier; mixing the oxidant with the fourth part of water to obtain an oxidant solution; mixing the reducing agent with the fifth part of water to obtain a reducing agent solution; mixing the modified rosin with part of the soft monomer to obtain a modified rosin solution;

[0065] (2) mixing the sixth portion of water, the pH buffer, the molecular weight regulator, the remaining emulsifier, the modified rosin solution obtained in step (1), the remaining soft monomer, the hard monomer and the functional monomer, and pre-emulsifying the mixture to obtain a pre-emulsified solution;

[0066] (3) mixing the seventh portion of water, the protective colloid, the priming initiator obtained in step (1), the pre-emulsion obtained in step (2), the dropping initiator obtained in step (1), and the secondary bunching emulsifier obtained in step (1), and performing a polymerization reaction to obtain an emulsion;

[0067] (4) The emulsion obtained in step (3) is mixed with a part of the pH adjuster and the remaining water, and the oxidant solution obtained in step (1), the reducing agent solution obtained in step (1), the remaining pH adjuster and the preservative are added in sequence for post-treatment to obtain a rosin-modified acrylic emulsion.

[0068] The present invention mixes part of the initiator with the first part of water to obtain a primer initiator; mixes the remaining initiator with the second part of water to obtain a drop-initiator; mixes part of the emulsifier with the third part of water to obtain a secondary bundled emulsifier; mixes the oxidant with the fourth part of water to obtain an oxidant solution; mixes the reductant with the fifth part of water to obtain a reductant solution; and mixes the modified rosin with part of the soft monomer to obtain a modified rosin solution.

[0069] The present invention mixes part of the initiator with the first part of water to obtain a primer initiator.

[0070] In the present invention, the mass of the partial initiator is preferably 40-50% of the mass of the total initiator, more preferably 42-46%. In the present invention, the mass ratio of the initiator to water in the primer initiator is preferably 0.13:(1.5-1.7).

[0071] The present invention mixes the remaining initiator with the second part of water to obtain the dropwise initiator.

[0072] In the present invention, the mass ratio of the initiator to water in the dropwise added initiator is preferably 0.1625:(3.5-4.0).

[0073] The present invention mixes part of the emulsifier with the third part of water to obtain a secondary bundled emulsifier.

[0074] In the present invention, the mass of the partial emulsifier is preferably 25-30% of the mass of the total emulsifier.

[0075] In the present invention, the mass ratio of the emulsifier to water in the secondary bunching emulsifier is preferably 0.91:(1.5-1.8).

[0076] The present invention mixes the oxidant with the fourth portion of water to obtain an oxidant solution.

[0077] In the present invention, the mass ratio of the oxidant to water in the oxidant solution is preferably 0.065:(0.5-0.6).

[0078] The present invention mixes the reducing agent with the fifth part of water to obtain a reducing agent solution.

[0079] In the present invention, the mass ratio of the reducing agent to water in the reducing agent solution is preferably 0.065:(0.5-0.6).

[0080] The invention mixes the modified rosin with part of the soft monomer to obtain the modified rosin solution.

[0081] In the present invention, the mass of the partial soft monomers is preferably 40-50% of the mass of the total soft monomers, and more preferably 45-50%.

[0082] In the present invention, in the modified rosin solution, the mass ratio of the modified rosin to the soft monomer is preferably (1.3-3.25):25.35.

[0083] After obtaining the primer initiator, the dripping initiator, the secondary bunching emulsifier, the oxidant solution, the reducing agent solution and the modified rosin solution, the present invention mixes the sixth part of water, the pH buffer, the molecular weight regulator, the remaining emulsifier, the modified rosin solution, the remaining soft monomer, the hard monomer and the functional monomer and then pre-emulsifies them to obtain a pre-emulsified liquid.

[0084] In the present invention, the mass ratio of the sixth part of water to the pH buffer is preferably (14-15):0.065.

[0085] In the present invention, the sixth part of water, pH buffer, molecular weight regulator, remaining emulsifier, the modified rosin solution, remaining soft monomer, hard monomer and functional monomer are preferably mixed as follows: firstly, the sixth part of water, pH buffer, molecular weight regulator and remaining emulsifier are mixed and stirred for 10 to 20 minutes, and then the modified rosin solution, remaining soft monomer, functional monomer and hard monomer are added in sequence.

[0086] In the present invention, the pre-emulsification is preferably carried out under stirring conditions; the stirring rate is preferably 30 to 40 Hz, more preferably 35 Hz; the stirring time is preferably 20 to 40 min, more preferably 30 min.

[0087] After obtaining the pre-emulsion, the present invention mixes the seventh part of water, the protective colloid, the primer initiator, the pre-emulsion, the dripping initiator and the secondary bundled emulsifier, and then performs polymerization reaction to obtain an emulsion.

[0088] In the present invention, the mass ratio of the seventh part of water to the protective colloid is preferably (9.5-10):0.052.

[0089] In the present invention, the seventh part of water, the protective colloid and the primer initiator, the pre-emulsion, the dripping initiator and the secondary bunching emulsifier are preferably mixed as follows: after the seventh part of water and the protective colloid are mixed, they are kept warm at 73-77°C for 50-70 minutes, the temperature is raised to 78-82°C and the primer initiator is added, and when the temperature is raised to 83-85°C, the pre-emulsion is dripped, and the dripping initiator is dripped after the pre-emulsion has been dripped for 20-40 minutes, and the dripping of the pre-emulsion is stopped when the pre-emulsion has been dripped to 55-65% of the total mass, the secondary bunching emulsifier is added, and the pre-emulsion is continued to be dripped after stirring for 4-6 minutes, and after the dripping initiator is finished, the temperature is kept at 85-87°C for 80-100 minutes.

[0090] In the present invention, the temperature when the pre-emulsion is added is preferably 84-86°C; the addition time of the pre-emulsion is preferably 3.5-4.5h, more preferably 4h; the dropping speed of the pre-emulsion in the first 20-40min is preferably 45-55% of the subsequent dropping speed of the pre-emulsion, more preferably the dropping speed of the pre-emulsion in the first 30min is preferably 50% of the subsequent dropping speed of the pre-emulsion.

[0091] In the present invention, the time for dripping the initiator is preferably 3.5 to 4.5 hours, more preferably 4 hours.

[0092] After obtaining the emulsion, the present invention mixes the emulsion with part of the pH regulator and the remaining water, and sequentially adds the oxidant solution, the reducing agent solution, the remaining pH regulator and the preservative for post-treatment in order to obtain the rosin-modified acrylic emulsion.

[0093] The preferred method of the present invention is as follows: a part of the pH regulator and the remaining water are mixed to obtain a diluted pH regulator solution, the emulsion is cooled to 65-75° C., the diluted pH regulator solution is added until the pH value of the system is 5-6, an oxidant solution is added dropwise, a reducing agent solution is added dropwise after 5-10 minutes, the temperature is lowered to 45-55° C. after 20-40 minutes, the remaining pH regulator is added until the pH value of the system is above 6, and a preservative is added.

[0094] In the present invention, the mass ratio of the part of the pH adjuster to the remaining water is preferably 1:(0.5-1.5), more preferably 1:1.

[0095] In the present invention, the time for adding the oxidant solution dropwise is preferably 8 to 12 minutes, more preferably 10 minutes; the time for adding the reducing agent dropwise is preferably 20 to 40 minutes, more preferably 30 minutes.

[0096] After the post-treatment is completed, the present invention preferably filters the post-treatment product to obtain a rosin-modified acrylic emulsion.

[0097] In the present invention, the filtration is preferably performed using a filter bag; the mesh size of the filter bag is preferably 300 meshes.

[0098] The rosin modified acrylic emulsion prepared by the preparation method of the invention has high solid content, good stability, small emulsion slag amount, good wettability and is suitable for curtain coating.

[0099] The present invention also provides an adhesive, which comprises, by weight, 70-79 parts of the rosin-modified acrylic emulsion described in the above technical solution or the rosin-modified acrylic emulsion prepared by the preparation method described in the above technical solution, 20-29 parts of rosin resin emulsion and 0.3-0.5 parts of a wetting agent.

[0100] The adhesive provided by the present invention comprises 70 to 79 parts by weight of rosin-modified acrylic emulsion, preferably 72 to 78 parts, and more preferably 74 to 77 parts. The present invention limits the amount of rosin-modified acrylic emulsion to the above range, which can further improve the initial adhesion, lasting adhesion and curtain formation of the adhesive.

[0101] Based on 70 to 79 parts by weight of the rosin-modified acrylic emulsion, the adhesive provided by the present invention includes 20 to 29 parts, preferably 22 to 28 parts, and more preferably 23 to 26 parts, of the rosin resin emulsion.

[0102] In the present invention, the solid content of the rosin resin emulsion is preferably 50-60%, more preferably 55%. The present invention has no special limitation on the source of the rosin resin emulsion, and a commercial product well known to those skilled in the art can be used. In an embodiment of the present invention, the rosin resin emulsion is preferably 780G rosin resin emulsion. The present invention limits the amount of the rosin resin emulsion to the above range, which can further improve the initial adhesion and the lasting adhesion of the adhesive.

[0103] Based on 70 to 79 parts by mass of the rosin-modified acrylic emulsion, the adhesive provided by the present invention includes 0.3 to 0.5 parts of a wetting agent, preferably 0.4 to 0.5 parts. The present invention has no particular limitation on the source of the wetting agent, and a commercial product well known to those skilled in the art can be used. In an embodiment of the present invention, the wetting agent is preferably a wetting agent OT-75.

[0104] In the present invention, the wetting agent is used to improve the leveling property and surface tension of the adhesive. The present invention limits the amount of the wetting agent to the above range, which can further improve the leveling property of the adhesive and make it have a suitable surface tension.

[0105] The invention controls the composition and dosage of the adhesive so that the adhesive has better initial adhesion, lasting adhesion and curtain-forming property.

[0106] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0107] Example 1

[0108] A rosin-modified acrylic emulsion is prepared from the following raw materials, measured by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate, from Guangzhou Bingding Chemical Trading Co., Ltd.), 7.8 parts of hard monomers (including 2.6 parts of versatate vinyl carbonate (Hansen VV-10, USA) and 5.2 parts of methyl methacrylate (from Guangzhou Bingding Chemical Trading Co., Ltd.), 1.95 parts of functional monomers (including 0.78 parts of methacrylic acid, 0.78 parts of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid, from Guangzhou Bingding Chemical Trading Co., Ltd.), 1.3 parts of hydrogenated rosin, 0. 0.052 parts of molecular weight regulator n-dodecyl mercaptan (Phillips, USA), 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sulfate sodium salt and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate (Shandong Jinli Chemical Co., Ltd.), 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kasson preservative (Jinan Delan Chemical Co., Ltd.) and 32.8465 parts of deionized water;

[0109] The preparation method of the rosin-modified acrylic emulsion is as follows: (1) dissolving 0.13 parts of ammonium persulfate (the mass of ammonium persulfate is 44.4% of the total mass) in 1.693 parts of deionized water to obtain 1.823 parts of a primer initiator (the mass ratio of ammonium persulfate to water is 0.13:1.693); dissolving 0.1625 parts of ammonium persulfate in 3.90 parts of deionized water to obtain 4.0625 parts of a dropwise initiator (the mass ratio of ammonium persulfate to water is 0.1625:3.9); dissolving 0.91 parts of allyl polyether sulfate in 1.69 parts of deionized water as a secondary bunching emulsifier (the mass of allyl polyether sulfate is 28% of the total emulsifier mass, the mass of allyl polyether sulfate and water is 28% of the total emulsifier mass); The mass ratio of tert-butyl hydroperoxide is 0.91:1.69); 0.065 parts of tert-butyl hydroperoxide are dissolved in 0.585 parts of deionized water to prepare an oxidant solution (the mass ratio of tert-butyl hydroperoxide to water is 0.065:0.585); 0.065 parts of sodium formaldehyde sulfoxylate are dissolved in 0.585 parts of deionized water to prepare a reducing agent solution (the mass ratio of sodium formaldehyde sulfoxylate to water is 0.065:0.585); 1.30 parts of hydrogenated rosin are added to 25.35 parts of butyl acrylate (the mass ratio of hydrogenated rosin to butyl acrylate is 1.3:25.35, and the mass of butyl acrylate is 48.75% of the mass of the total soft monomer) and filtered at 35 Hz for 30 minutes to prepare 26.65 parts of hydrogenated rosin solution;

[0110] (2) adding 14.30 parts of deionized water, 0.065 parts of sodium bicarbonate (the mass ratio of water to sodium bicarbonate is 14.3:0.065), 0.052 parts of n-dodecyl mercaptan, 2.08 parts of allyl polyether sulfate and 0.26 parts of fatty alcohol polyoxyethylene ether to a pre-emulsification tank, stirring for 15 minutes, and sequentially adding 26.65 parts of hydrogenated rosin solution in step (1), 26.652 parts of isooctyl acrylate, 0.78 parts of methacrylic acid, 0.78 parts of hydroxyethyl methacrylate, 0.39 parts of β-acryloxypropionic acid, 2.60 parts of tert-butyl vinyl carbonate and 5.20 parts of methyl methacrylate, and stirring at 35 Hz for 30 minutes to obtain 79.809 parts of pre-emulsion;

[0111] (3) Add 9.90 parts of deionized water and 0.052 parts of sodium polyacrylate (the mass ratio of water to sodium polyacrylate is 9.9:0.052) to the reaction kettle, heat to 75°C and keep warm for 60 minutes. After it is completely dissolved, heat to 80°C and add the primer initiator in step (1). When the temperature rises to 84°C, add 79.809 parts of the pre-emulsion in step (2) dropwise. The reaction temperature is controlled between 84 and 86°C. The pre-emulsion is added dropwise for 4 hours, with half the speed in the first half hour. Add dropwise, add dropwise at full speed for the last 3.5 hours, start adding the dropwise initiator in step (1) half an hour after the emulsion has been added dropwise, the dropping time is 4 hours, stop adding the pre-emulsion when the pre-emulsion has been added to 60% of the total mass, i.e., 47.71 parts of the pre-emulsion have been added dropwise, add the secondary bunching emulsifier prepared in step (1), continue to add dropwise the pre-emulsion after stirring for five minutes, and after the dropwise initiator has been added dropwise, control the temperature between 85 and 87° C. and keep warm for 90 minutes to obtain an emulsion;

[0112] (4) The emulsion in step (3) is cooled to 70° C., 0.39 parts of diluted ammonia water (the mass ratio of ammonia water (mass concentration is 25%) to deionized water is 1:1), the pH value is adjusted to 5.5, the oxidant solution in step (1) is added dropwise, and the dripping is completed within 10 minutes. After pausing for 10 minutes, the reducing agent solution in step (1) is added dropwise, and the dripping is completed within 30 minutes. The mixture is kept warm for 30 minutes, cooled to 50° C., 0.195 parts of ammonia water (mass concentration is 25%) are added to adjust the pH value to 6.5, 0.065 parts of preservative are added, and the material is filtered through a 300-mesh filter bag to obtain a rosin-modified acrylic emulsion.

[0113] Example 2

[0114] A rosin-modified acrylic emulsion is prepared from the following raw materials, calculated by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate), 7.8 parts of hard monomers (including 2.6 parts of tert-butyl carbonate and 5.2 parts of methyl methacrylate), 2.39 parts of functional monomers (including 1 part of methacrylic acid, 1 part of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid), 1.3 parts of hydrogenated rosin, and 0.052 parts of a molecular weight regulator, dialkyl mercaptan, 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sulfate sodium salt and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate, 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kathon preservative and 32.8465 parts of deionized water;

[0115] The preparation method of the rosin-modified acrylic emulsion is the same as that of Example 1.

[0116] Example 3

[0117] A rosin-modified acrylic emulsion is prepared from the following raw materials, measured by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate), 6.8 parts of hard monomers (including 2.6 parts of tert-butyl carbonate and 4.2 parts of methyl methacrylate), 3.39 parts of functional monomers (including 1.5 parts of methacrylic acid, 1.5 parts of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid), 1.3 parts of hydrogenated rosin, and 0.052 parts of a molecular weight regulator. n-dodecyl mercaptan, 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sulfate sodium salt and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate, 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kathon preservative and 32.8465 parts of deionized water;

[0118] The preparation method of the rosin-modified acrylic emulsion is the same as that of Example 1.

[0119] Example 4

[0120] A rosin-modified acrylic emulsion is prepared from the following raw materials, measured by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate), 5.8 parts of hard monomers (including 2.6 parts of tert-butyl carbonate and 3.2 parts of methyl methacrylate), 4.39 parts of functional monomers (including 2 parts of methacrylic acid, 2 parts of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid), 1.3 parts of hydrogenated rosin, and 0.052 parts of a molecular weight regulator, dialkyl mercaptan, 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sulfate sodium salt and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate, 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kathon preservative and 32.8465 parts of deionized water;

[0121] The preparation method of the rosin-modified acrylic emulsion is the same as that of Example 1.

[0122] Example 5

[0123] A rosin-modified acrylic emulsion is prepared from the following raw materials, measured by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate), 5.8 parts of hard monomers (including 2.6 parts of tert-butyl carbonate and 3.2 parts of methyl methacrylate), 4.39 parts of functional monomers (including 2 parts of methacrylic acid, 2 parts of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid), 1.5 parts of hydrogenated rosin, and 0.052 parts of a molecular weight regulator, dialkyl mercaptan, 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sulfate sodium salt and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate, 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kathon preservative and 32.8465 parts of deionized water;

[0124] The preparation method of the rosin-modified acrylic emulsion is the same as that of Example 1.

[0125] Example 6

[0126] A rosin-modified acrylic emulsion is prepared from the following raw materials, calculated by weight: 52.002 parts of soft monomers (including 25.35 parts of butyl acrylate and 26.652 parts of isooctyl acrylate), 5.8 parts of hard monomers (including 2.6 parts of tert-butyl carbonate and 3.2 parts of methyl methacrylate), 4.39 parts of functional monomers (including 2 parts of methacrylic acid, 2 parts of hydroxyethyl methacrylate and 0.39 parts of β-acryloxypropionic acid), 2 parts of hydrogenated rosin, and 0.052 parts of a molecular weight regulator, n-dodecyl acrylate. Alkyl mercaptan, 3.25 parts of emulsifier (including 2.99 parts of allyl polyether sodium sulfate and 0.26 parts of fatty alcohol polyoxyethylene ether), 0.052 parts of protective colloid sodium polyacrylate, 0.065 parts of pH buffer sodium bicarbonate, 0.2925 parts of initiator ammonium persulfate, 0.065 parts of oxidant tert-butyl hydroperoxide, 0.065 parts of reducing agent sodium formaldehyde sulfoxylate, 0.39 parts of pH regulator ammonia water (mass concentration 25%), 0.065 parts of Kathon preservative and 32.8465 parts of deionized water;

[0127] The preparation method of the rosin-modified acrylic emulsion is the same as that of Example 1.

[0128] Example 7

[0129] The versatate vinyl carbonate in Example 1 was omitted, the amount of methyl methacrylate was replaced by 6.6 parts, the amount of isooctyl acrylate was replaced by 27.852 parts, and the other parameters were the same as those in Example 1.

[0130] Comparative Example 1

[0131] The hydrogenated rosin in Example 1 was omitted, and other parameters were the same as those in Example 1.

[0132] Comparative Example 2

[0133] The protective colloid sodium polyacrylate in Example 1 was omitted, and other parameters were the same as those in Example 1.

[0134] The viscosity, solid content, pH value, sieve residue and surface tension of the emulsions in Examples 1 to 7 and Comparative Examples 1 to 2 were tested. The results are shown in Table 1.

[0135] Table 1 Viscosity, solid content, pH value, sieve residue and surface tension of the emulsions in Examples 1 to 7 and Comparative Examples 1 to 2

[0136]

[0137]

[0138] It can be seen from Table 1 that the emulsion of the present invention achieves the purpose of high solid and low viscosity, and the addition of a very small amount of protective colloid helps to reduce the slag discharge of the emulsion.

[0139] Application Example 1

[0140] An adhesive is prepared from 76.5 parts of the rosin-modified acrylic emulsion in Example 1, 23 parts of the rosin resin emulsion and 0.5 parts of a wetting agent OT-75.

[0141] Application Example 2

[0142] An adhesive is prepared from 76.5 parts of the rosin-modified acrylic emulsion in Example 2, 23 parts of the rosin resin emulsion and 0.5 parts of a wetting agent OT-75.

[0143] Application Example 3

[0144] An adhesive is prepared from 76.5 parts of the rosin-modified acrylic emulsion in Example 3, 23 parts of the rosin resin emulsion and 0.5 parts of a wetting agent OT-75.

[0145] Application Example 4

[0146] An adhesive is prepared from 76.7 parts of the rosin-modified acrylic emulsion in Example 4, 23 parts of a rosin resin emulsion and 0.3 parts of a wetting agent OT-75.

[0147] Application Example 5

[0148] An adhesive is prepared from 76.7 parts of the rosin-modified acrylic emulsion in Example 5, 23 parts of a rosin resin emulsion and 0.3 parts of a wetting agent OT-75.

[0149] Application Example 6

[0150] An adhesive is prepared from 76.7 parts of the rosin-modified acrylic emulsion in Example 6, 23 parts of the rosin resin emulsion and 0.3 parts of the wetting agent OT-75.

[0151] Application Example 7

[0152] An adhesive is prepared from 76.7 parts of the rosin-modified acrylic emulsion in Example 7, 23 parts of a rosin resin emulsion and 0.3 parts of a wetting agent OT-75.

[0153] Comparative application example 1

[0154] An adhesive is prepared from 71 parts of the acrylic emulsion in Comparative Example 1, 28.5 parts of the rosin resin emulsion and 0.5 parts of the wetting agent OT-75.

[0155] Comparative Application Example 2

[0156] An adhesive is prepared from 76.5 parts of the acrylic emulsion in Comparative Example 2, 23 parts of the rosin resin emulsion and 0.5 parts of the wetting agent OT-75.

[0157] Test Case

[0158] The adhesives in Application Examples 1 to 7 and Comparative Application Examples 1 to 2 were coated on a 61 g / m 2 White release paper with silicone coating, the coating amount is 19.0±1g / m 2 After coating, put it into a 95℃ oven for 8 minutes and take it out. Then transfer the film to 80g / m 2 The gluing surface of the mirror coated paper is finally laminated to 61g / m 2 The silicon-coated surface of the white release paper was balanced for 72 hours under standard conditions (temperature 23±2°C, humidity 50±5%), and its loop initial adhesion, peeling force, sustained adhesion, and 10°C PE initial adhesion were tested and the curtaining was observed. The results are shown in Table 2. Among them, initial adhesion: tested according to the "loop initial adhesion test" FTM9; peeling force: tested according to the "90° peeling force test" FTM2; sustained adhesion: tested according to the "sustaining adhesion test on the standard panel" FTM8; 10°C PE initial adhesion: the label to be tested and the PE test plate were placed at 10°C for 24 hours for initial adhesion test.

[0159] Table 2 Composition of adhesives in application examples 1 to 7 and comparative application examples 1 to 2 and their ring initial adhesion, peel strength, sustained adhesion, 10℃ PE initial adhesion and curtain formation

[0160]

[0161]

[0162] As can be seen from Table 2, the mechanical properties of the adhesive prepared by adding modified rosin, functional monomers methacrylic acid, hydroxyethyl methacrylate, β-acryloxypropionic acid, and hard monomer tert-butyl vinyl carbonate and synthetic emulsion are as follows: initial adhesion>19N / 25mm, peel strength>10N / 25mm, lasting adhesion>16h, low temperature 10℃ PE initial adhesion>9N / 25mm, good curtain forming property, which solves the problem of low or unbalanced mechanical properties of existing adhesives.

[0163] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A rosin-modified acrylic emulsion, comprising the following raw materials, by weight: 50-56 parts of soft monomers, 5-10 parts of hard monomers, 1.95-5 parts of functional monomers, 1-5 parts of modified rosin, 0.02-0.06 parts of molecular weight regulators, 2-5 parts of emulsifiers, 0.01-0.1 parts of protective colloids, 0.02-0.1 parts of pH buffers, 0.2-0.6 parts of initiators, 0.01-0.1 parts of oxidants, 0.01-0.1 parts of reducing agents, 0.01-1 parts of pH regulators, 0.05-0.5 parts of preservatives and 30-40 parts of water.

2. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The soft monomer includes one or more of n-butyl acrylate, isooctyl acrylate and ethyl acrylate.

3. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The hard monomer includes one or more of methyl methacrylate, styrene and vinyl versatate.

4. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The functional monomers include one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and β-acryloxypropionic acid.

5. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The molecular weight regulator includes one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol and thioglycolic acid.

6. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The protective colloid includes one or more of sodium polyacrylate, sodium polymethacrylate, sodium tripolyphosphate, gum arabic, polyethylene oxide and hydroxymethyl cellulose.

7. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The modified rosin includes one or more of hydrogenated rosin and hydrogenated rosin glycerol ester.

8. The rosin-modified acrylic emulsion according to claim 1, characterized in that: The emulsifier includes one or more of sodium acrylamido-2-methylpropane sulfonate, sodium vinyl sulfonate, allyl polyether sulfate, fatty alcohol polyoxyethylene ether and alkenyl polyoxyethylene ether.

9. The method for preparing the rosin-modified acrylic emulsion according to any one of claims 1 to 8, comprising the following steps: (1) mixing part of the initiator with the first part of water to obtain a primer initiator; mixing the remaining initiator with the second part of water to obtain a drop initiator; mixing part of the emulsifier with the third part of water to obtain a secondary bundled emulsifier; mixing the oxidant with the fourth part of water to obtain an oxidant solution; mixing the reducing agent with the fifth part of water to obtain a reducing agent solution; mixing the modified rosin with part of the soft monomer to obtain a modified rosin solution; (2) mixing the sixth portion of water, the pH buffer, the molecular weight regulator, the remaining emulsifier, the modified rosin solution obtained in step (1), the remaining soft monomer, the hard monomer and the functional monomer, and pre-emulsifying the mixture to obtain a pre-emulsified solution; (3) mixing the seventh portion of water, the protective colloid, the priming initiator obtained in step (1), the pre-emulsion obtained in step (2), the dropping initiator obtained in step (1), and the secondary bunching emulsifier obtained in step (1), and performing a polymerization reaction to obtain an emulsion; (4) The emulsion obtained in step (3) is mixed with a part of the pH adjuster and the remaining water, and the oxidant solution obtained in step (1), the reducing agent solution obtained in step (1), the remaining pH adjuster and the preservative are added in sequence for post-treatment to obtain a rosin-modified acrylic emulsion.

10. An adhesive comprising, by weight, 70-79 parts of the rosin-modified acrylic emulsion according to any one of claims 1 to 8 or the rosin-modified acrylic emulsion prepared by the preparation method according to claim 9, 20-29 parts of rosin resin emulsion and 0.3-0.5 parts of a wetting agent.

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