Emulsion for water-based plastic table printing ink and preparation method thereof

Abstract

The invention relates to the technical field of emulsions, in particular to an emulsion for water-based plastic table printing ink and a preparation method of the emulsion for the water-based plastic table printing ink. Comprising the following components: 40%-60% of water, 5%-15% of resin, 1%-10% of an A3 emulsifier, 5%-10% of ammonia water, 0.5%-2% of an A4 surfactant, 10%-20% of methyl methacrylate B11, 12%-30% of octyl acrylate B13, 0.1%-1% of a functional monomer and 0.1%-1% of a cross-linking agent. According to the emulsion, water is used as a main solvent, and benzene series organic solvents such as methylbenzene and dimethylbenzene which are used in a large amount in a traditional emulsion are abandoned; therefore, in the ink drying process, the discharge amount of volatile organic compounds, namely VOCs, is greatly reduced and even approaches to zero, the pollution to the atmospheric environment is effectively reduced, the harm to human health is reduced, the problems of falling and fading of printed patterns caused by low adhesive force of a traditional emulsion are effectively solved, and the printing quality is improved. And the quality and the service life of printed matters are remarkably improved, and the printing quality is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of emulsions, in particular to an emulsion for water-based plastic surface printing ink and a preparation method thereof. Background Art

[0002] Traditional plastic surface printing ink emulsions mostly use benzene-based organic solvents as the main solvent, such as toluene and xylene. These organic solvents evaporate in large quantities during the ink drying process, which is not environmentally friendly and safe, and the VOCs exceed the standard. VOCs not only cause serious pollution to the atmospheric environment, forming photochemical smog, which is harmful to human health, but long-term exposure may also cause respiratory diseases, nervous system damage and even cancer risks. At the same time, benzene-based organic solvents are flammable and explosive, and there are major safety hazards in the production, storage and use of inks, which increases the company's safety management costs and risks.

[0003] Traditional water-based ink resins mostly use a single type of resin, such as ordinary acrylic resin; this type of resin has relatively weak adhesion and is difficult to firmly adhere to the plastic surface, resulting in problems such as the printed pattern easily falling off and fading during subsequent use, seriously affecting the quality and service life of the printed product; in addition, after the single resin is formed into a film, its surface hardness is low, and it is easy to scratch the printing plate and scraper during the printing process, which not only increases the replacement frequency of the printing plate and scraper and increases production costs, but also affects printing efficiency and printing accuracy; due to the high surface tension of the emulsion, the ink has poor spreading properties on the plastic surface, resulting in uneven ink transfer during printing, Problems such as uneven ink color and blurred dots reduce the printing quality. In addition, after the traditional emulsion dries, the ink film is prone to crusting, especially in high temperature and high humidity environments, the crusting problem is more serious, affecting the fluidity of the ink; during the printing process, the ink made of traditional water-based binders also has the problem of insufficient gloss, and the surface of the printed product appears dull and cannot meet the requirements of the high-end printing market for product appearance. Moreover, the rheology of the ink is not ideal, which can easily lead to network blocking during the printing process. Especially in fine printing, the network blocking problem seriously affects printing efficiency and printing quality, and increases the cleaning and maintenance costs during the printing process.

[0004] Therefore, in view of the above-mentioned problems that the traditional emulsion is not environmentally friendly and has insufficient performance, its water-based binder has poor adhesion, no glossiness, and is easy to block the network, a water-based plastic surface printing ink emulsion and its preparation method can be designed. Summary of the invention

[0005] In order to overcome the problems of traditional emulsions' insufficient environmental protection and performance, its water-based binder has weak adhesion, no glossiness, and easy clogging of the network.

[0006] The technical solution of the present invention is as follows: An emulsion for water-based plastic surface printing ink, calculated by mass percentage, includes the following components: 40% - 60% of water, 5% - 15% of resin, 1% - 10% of A3 emulsifier, 5% - 10% of ammonia water, 0.5% - 2% of A4 surfactant, 10% - 20% of methyl methacrylate B11, 2% - 30% of octyl acrylate B13, 0.1% - 1% of functional monomer, and 0.1% - 1% of crosslinking agent.

[0007] Preferably, the resin is any one or a combination of acrylic resin, polyurethane resin, and styrene-acrylic resin, and the blending ratio ranges from 1:1:1 to 1:3:2.

[0008] Preferably, the A3 emulsifier is a compound of a non-ionic emulsifier and an anionic emulsifier in a mass ratio of 1:1 - 2:1. The anionic emulsifier is specifically any one of sodium dodecylbenzenesulfonate and sodium alkylphenol polyoxyethylene ether sulfate.

[0009] Preferably, the A4 surfactant is an organosilicon surfactant or a fluorocarbon surfactant.

[0010] Preferably, the functional monomer is a monomer containing functional groups such as hydroxyl, carboxyl, and amino groups, specifically any one or more of hydroxyethyl methacrylate, acrylic acid, and methacrylamide. The functional monomer can react with the crosslinking agent to form a crosslinked structure, enhancing the adhesion and abrasion resistance of the ink.

[0011] Preferably, the crosslinking agent is any one of aziridine crosslinking agents and carbodiimide crosslinking agents. The addition of the crosslinking agent makes the emulsion form a three-dimensional network structure, improving the water resistance, solvent resistance, and hardness of the ink.

[0012] Preferably, the solid content of the emulsion is 30% - 50%, and the pH value of the emulsion is 7.5 - 9.0. Within this pH value range, the emulsion has the best stability and is beneficial to the transfer and drying of the ink during the printing process.

[0013] A preparation method of an emulsion for water-based plastic surface printing ink, which includes an emulsion for water-based plastic surface printing ink as described above, and the steps are as follows:

[0014] S1: Pre-emulsification stage

[0015] S11: Add 40% - 60% of the formula amount of water to a clean container, turn on the stirring device, and adjust the stirring speed to 200 - 300 r / min;

[0016] S12: Add 1% - 10% of the A3 emulsifier and 0.5% - 2% of the A4 surfactant in sequence, stir evenly, and make the emulsifier and surfactant fully dissolve in water;

[0017] S13: Slowly add 10% - 20% methyl methacrylate B11 and 12% - 30% octyl acrylate B13 to the above solution, and continue stirring for 30 - 60 min to form a uniform and stable pre-emulsion. During the stirring process, appropriately increase the stirring speed to 300 - 400 r / min to promote the full dispersion of the monomers in the aqueous phase;

[0018] S2: Monomer polymerization stage

[0019] S21: Transfer the above pre-emulsion to a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, heat up to 75 - 85 °C, and maintain this temperature;

[0020] S22: Add 0.1% - 1% initiator to the four-necked flask to initiate the monomer polymerization reaction;

[0021] S23: After a slight reflux phenomenon appears in the reaction system, slowly add the remaining pre-emulsion containing 0.1% - 1% functional monomer to the four-necked flask through the dropping funnel. The dropping time is controlled within 2 - 3 h, and the reaction temperature is kept stable during the dropping process;

[0022] S24: After the dropping is completed, continue the heat preservation reaction for 1 - 2 h to ensure the full polymerization of the monomers, and improve the degree of polymerization and stability of the emulsion;

[0023] S3: Neutralization and crosslinking stage

[0024] S31: After the reaction is completed, lower the temperature of the reaction system to 40 - 50 °C;

[0025] S32: Slowly add 5% - 10% ammonia water for neutralization, adjust the pH value of the emulsion to 7.5 - 9.0, and stir while adding to ensure the full progress of the neutralization reaction;

[0026] S33: Add 0.1% - 1% crosslinking agent, and continue stirring for 30 - 60 min to make the crosslinking agent fully react with the functional groups in the emulsion to form a crosslinked structure and improve the performance of the emulsion;

[0027] S4: Post-treatment stage

[0028] S41: After the stirring is completed, filter the emulsion through a 100 - 200 mesh filter screen to remove the gels and impurities existing in the emulsion, and obtain a pure emulsion for water-based plastic surface printing ink;

[0029] S42: Transfer the filtered emulsion to a clean storage container, seal it for storage, and control the storage temperature at 5 - 30 °C to avoid direct sunlight and high-temperature environment to ensure the storage stability of the emulsion.

[0030] Preferably, the initiator in step S22 is specifically ammonium persulfate.

[0031] Advantages of the present invention: The emulsion of the present invention uses water as the main solvent, and abandons the benzene-based organic solvents such as toluene and xylene that are widely used in traditional emulsions. This significantly reduces or even approaches zero the emissions of volatile organic compounds, i.e., VOCs, during the drying process of the ink, effectively reducing the pollution to the atmospheric environment, avoiding the formation of photochemical smog, reducing the harm to human health, eliminating the safety hazards caused by the flammable and explosive characteristics of organic solvents, greatly reducing the costs and risks of enterprises in safety management, conforming to the current development trend of green environmental protection, and meeting the relevant standards and requirements of the state for environmentally friendly inks.

[0032] By compounding multiple resins such as acrylic resin, polyurethane resin, and styrene-acrylic resin, the advantages of different resins are complementary. The excellent abrasion resistance of polyurethane resin is combined with the good film-forming property of acrylic resin and the high gloss of styrene-acrylic resin, enabling the ink film formed by the emulsion to firmly adhere to the plastic surface. At the same time, functional monomers react with crosslinking agents to form a crosslinked structure, further enhancing the bonding force between the ink and the plastic substrate, effectively solving the problems of printing pattern peeling and color fading caused by the weak adhesion of traditional emulsions, and significantly improving the quality and service life of printed products.

[0033] After multiple resins are compounded into a film, it has a suitable surface hardness and is not likely to scratch the printing plate and doctor blade during the printing process, reducing the replacement frequency of the printing plate and doctor blade, lowering the production cost, while ensuring the printing efficiency and printing accuracy, and making the printing process smoother and more stable.

[0034] The A3 emulsifier is compounded with non-ionic and anionic types, and the A4 surfactant is selected from silicone or fluorocarbon surfactants, effectively reducing the surface tension of the emulsion, significantly improving the spreading property of the ink on the plastic surface, ensuring uniform ink transfer during printing, avoiding problems such as uneven ink color and blurred dots, and greatly enhancing the printing quality.

[0035] Through reasonable composition design and process control, the problem that the ink film is prone to skinning after drying of traditional emulsions is effectively solved. Even in high-temperature and high-humidity environments, the ink can still maintain good fluidity, ensuring the continuity and stability of the printing process.

[0036] The synergistic effect of multiple resins and the scientific formulation design enable the ink made from this emulsion to have a high gloss after printing. The surface of the printed product is smooth and bright, which can meet the strict requirements of the high-end printing market for the product appearance, and enhance the market competitiveness of the product.

[0037] The optimized emulsion formulation endows the ink with ideal rheology, effectively avoiding screen clogging during printing, especially in fine printing, reducing the cleaning and maintenance costs during printing, improving printing efficiency and quality, and being applicable to various complex patterns and high-precision printing requirements. Detailed implementation mode

[0038] The present invention will be further described below in conjunction with embodiments.

[0039] The present invention provides an embodiment: An emulsion for water-based plastic surface printing ink, in terms of mass percentage, comprises the following components: 40% - 60% of water, 5% - 15% of resin, 1% - 10% of A3 emulsifier, 5% - 10% of ammonia water, 0.5% - 2% of A4 surfactant, 10% - 20% of methyl methacrylate B11, 12% - 30% of octyl acrylate B13, 0.1% - 1% of functional monomer, and 0.1% - 1% of crosslinking agent.

[0040] The resin is any one or a combination of acrylic resin, polyurethane resin, and styrene-acrylic resin, and the compounding ratio ranges from 1:1:1 to 1:3:2.

[0041] The A3 emulsifier is a compound of a non-ionic emulsifier and an anionic emulsifier in a mass ratio of 1:1 - 2:1. The anionic emulsifier is specifically any one of sodium dodecyl benzene sulfonate and sodium alkylphenol polyoxyethylene ether sulfate.

[0042] The A4 surfactant is an organosilicon surfactant or a fluorocarbon surfactant.

[0043] The functional monomer is a monomer containing functional groups such as hydroxyl, carboxyl, and amino groups, specifically any one or more of hydroxyethyl methacrylate, acrylic acid, and methacrylamide. The functional monomer can react with the crosslinking agent to form a crosslinked structure, enhancing the adhesion and abrasion resistance of the ink.

[0044] The crosslinking agent is any one of aziridine crosslinking agents and carbodiimide crosslinking agents. The addition of the crosslinking agent enables the emulsion to form a three-dimensional network structure, improving the water resistance, solvent resistance, and hardness of the ink.

[0045] The solid content of the emulsion is 30% - 50%, and the pH value of the emulsion is 7.5 - 9.0. Within this pH value range, the emulsion has the best stability and is beneficial to the transfer and drying of the ink during printing.

[0046] A preparation method of an emulsion for water-based plastic surface printing ink, which comprises an emulsion for water-based plastic surface printing ink as described above, and the steps are as follows:

[0047] S1: Pre-emulsification stage

[0048] S11: Add 40% - 60% of the formulated amount of water into a clean container, turn on the stirring device, and adjust the stirring speed to 200 - 300 r / min;

[0049] S12: Sequentially add 1% - 10% of A3 emulsifier and 0.5% - 2% of A4 surfactant, stir evenly to fully dissolve the emulsifier and surfactant in water;

[0050] S13: Slowly add 10% - 20% of methyl methacrylate B11 and 12% - 30% of octyl acrylate B13 to the above solution, continue stirring for 30 - 60 min to form a uniform and stable pre - emulsion. During the stirring process, appropriately increase the stirring speed to 300 - 400 r / min to promote the full dispersion of monomers in the aqueous phase;

[0051] S2: Monomer polymerization stage

[0052] S21: Transfer the above pre - emulsion to a four - necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, heat up to 75 - 85 °C, and maintain this temperature;

[0053] S22: Add 0.1% - 1% of initiator to the four - necked flask to initiate the monomer polymerization reaction;

[0054] S23: After a slight reflux phenomenon appears in the reaction system, slowly add the remaining pre - emulsion containing 0.1% - 1% of functional monomer to the four - necked flask through the dropping funnel. Control the dropping time within 2 - 3 h and keep the reaction temperature stable during the dropping process;

[0055] S24: After the dropping is completed, continue the heat - preservation reaction for 1 - 2 h to ensure the full polymerization of monomers and improve the polymerization degree and stability of the emulsion;

[0056] S3: Neutralization and cross - linking stage

[0057] S31: After the reaction ends, lower the temperature of the reaction system to 40 - 50 °C;

[0058] S32: Slowly add 5% - 10% of ammonia water for neutralization, adjust the pH value of the emulsion to 7.5 - 9.0, stir while adding to ensure the full progress of the neutralization reaction;

[0059] S33: Add 0.1% - 1% of cross - linker, continue stirring for 30 - 60 min to make the cross - linker fully react with the functional groups in the emulsion to form a cross - linked structure and improve the emulsion performance;

[0060] S4: Post - treatment stage

[0061] S41: After the stirring is completed, filter the emulsion through a 100-200 mesh filter screen to remove the gels and impurities present in the emulsion, and obtain a pure emulsion for water-based plastic surface printing ink.

[0062] S42: Transfer the filtered emulsion to a clean storage container, seal it, and control the storage temperature at 5-30 °C to avoid direct sunlight and high-temperature environments, ensuring the storage stability of the emulsion.

[0063] The initiator in step S22 is specifically ammonium persulfate.

[0064] Example 1

[0065] The present invention provides an example: An emulsion for water-based plastic surface printing ink, by mass percentage, includes the following components: water 40%, resin 5%, A3 emulsifier 1%, ammonia water 5%, A4 surfactant 0.5%, methyl methacrylate B11 10%, octyl acrylate B13 12%, functional monomer 0.1%, and crosslinking agent 0.1%.

[0066] The resin is any one or a combination of acrylic resin, polyurethane resin, and styrene-acrylic resin, and the mixing ratio ranges from 1:1:1.

[0067] A3 emulsifier is a compound of a non-ionic emulsifier and an anionic emulsifier in a mass ratio of 1:1. The anionic emulsifier is specifically any one of sodium dodecylbenzenesulfonate and sodium alkylphenol polyoxyethylene ether sulfate.

[0068] A4 surfactant is an organosilicon surfactant or a fluorocarbon surfactant.

[0069] The functional monomer is a monomer containing functional groups such as hydroxyl, carboxyl, and amino groups, specifically any one or more of hydroxyethyl methacrylate, acrylic acid, and methacrylamide. The functional monomer can react with the crosslinking agent to form a crosslinked structure, enhancing the adhesion and abrasion resistance of the ink.

[0070] The crosslinking agent is any one of aziridine crosslinking agents and carbodiimide crosslinking agents. The addition of the crosslinking agent makes the emulsion form a three-dimensional network structure, improving the water resistance, solvent resistance, and hardness of the ink.

[0071] The solid content of the emulsion is 30%, and the pH value of the emulsion is 7.5 - 9.0. Within this pH value range, the emulsion has the best stability and is beneficial to the transfer and drying of the ink during the printing process.

[0072] A preparation method of an emulsion for water-based plastic surface printing ink, which includes an emulsion for water-based plastic surface printing ink as described above, and its steps are as follows:

[0073] S1: Pre-emulsification stage

[0074] S11: Add 40% of the formulated amount of water into a clean container, turn on the stirring device, and adjust the stirring speed to 200 - 300 r / min;

[0075] S12: Sequentially add 1% of emulsifier A3 and 0.5% of surfactant A4, stir evenly to fully dissolve the emulsifier and surfactant in water;

[0076] S13: Slowly add 10% of methyl methacrylate B11 and 12% of octyl acrylate B13 into the above solution, continue stirring for 30 - 60 min to form a uniform and stable pre - emulsion. During the stirring process, appropriately increase the stirring speed to 300 - 400 r / min to promote the full dispersion of monomers in the aqueous phase;

[0077] S2: Monomer polymerization stage

[0078] S21: Transfer the above pre - emulsion into a four - necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, heat up to 75 - 85 °C, and maintain this temperature;

[0079] S22: Add 0.1% of initiator into the four - necked flask to initiate the monomer polymerization reaction. The initiator specifically uses ammonium persulfate;

[0080] S23: After a slight reflux phenomenon appears in the reaction system, slowly add the remaining pre - emulsion containing 0.1% of functional monomer into the four - necked flask through the dropping funnel. The dropping time is controlled within 2 - 3 h, and the reaction temperature is kept stable during the dropping process;

[0081] S24: After the dropping is completed, continue the heat - preservation reaction for 1 - 2 h to ensure the full polymerization of monomers, and improve the polymerization degree and stability of the emulsion;

[0082] S3: Neutralization and cross - linking stage

[0083] S31: After the reaction ends, lower the temperature of the reaction system to 40 - 50 °C;

[0084] S32: Slowly add 5% of ammonia water for neutralization, adjust the pH value of the emulsion to 7.5 - 9.0, stir while adding to ensure the full progress of the neutralization reaction;

[0085] S33: Add 0.1% of cross - linker, continue stirring for 30 - 60 min to fully react the cross - linker with the functional groups in the emulsion to form a cross - linked structure and improve the emulsion performance;

[0086] S4: Post - treatment stage

[0087] S41: After stirring is completed, filter the emulsion through a 100 - 200 mesh filter screen to remove the gels and impurities present in the emulsion, obtaining a pure emulsion for water-based plastic surface printing ink;

[0088] S42: Transfer the filtered emulsion to a clean storage container, seal it for storage, and control the storage temperature at 5 - 30 °C, avoiding direct sunlight and high-temperature environments to ensure the storage stability of the emulsion.

[0089] Example 2

[0090] The present invention provides an example: An emulsion for water-based plastic surface printing ink, in terms of mass percentage, includes the following components: 60% water, 15% resin, 10% A3 emulsifier, 10% ammonia water, 2% A4 surfactant, 20% methyl methacrylate B11, 30% octyl acrylate B13, 1% functional monomer, and 1% crosslinking agent.

[0091] The resin is any one or a combination of acrylic resin, polyurethane resin, and styrene-acrylic resin, and the mixing ratio ranges from 1:3:2.

[0092] The A3 emulsifier is a compound of a non-ionic emulsifier and an anionic emulsifier in a mass ratio of 2:1. The anionic emulsifier is specifically any one of sodium dodecylbenzenesulfonate and sodium alkylphenol polyoxyethylene ether sulfate.

[0093] The A4 surfactant is an organosilicon surfactant or a fluorocarbon surfactant.

[0094] The functional monomer is a monomer containing functional groups such as hydroxyl, carboxyl, and amino groups, specifically any one or more of hydroxyethyl methacrylate, acrylic acid, and methacrylamide. The functional monomer can react with the crosslinking agent to form a crosslinked structure, enhancing the adhesion and abrasion resistance of the ink.

[0095] The crosslinking agent is any one of aziridine crosslinking agents and carbodiimide crosslinking agents. The addition of the crosslinking agent enables the emulsion to form a three-dimensional network structure, improving the water resistance, solvent resistance, and hardness of the ink.

[0096] The solid content of the emulsion is 50%, and the pH value of the emulsion is 7.5 - 9.0. Within this pH value range, the emulsion has the best stability and is beneficial to the transfer and drying of the ink during the printing process.

[0097] A preparation method of an emulsion for water-based plastic surface printing ink, which includes an emulsion for water-based plastic surface printing ink as described above, and its steps are as follows:

[0098] S1: Pre-emulsification stage

[0099] S11: Add 60% of the formulated amount of water into a clean container, turn on the stirring device, and adjust the stirring speed to 200 - 300 r / min;

[0100] S12: Add 10% of A3 emulsifier and 2% of A4 surfactant in sequence, stir evenly to fully dissolve the emulsifier and surfactant in water;

[0101] S13: Slowly add 20% of methyl methacrylate B11 and 30% of octyl acrylate B13 into the above solution, continue to stir for 30 - 60 min to form a uniform and stable pre - emulsion. During the stirring process, appropriately increase the stirring speed to 300 - 400 r / min to promote the full dispersion of monomers in the aqueous phase;

[0102] S2: Monomer polymerization stage

[0103] S21: Transfer the above pre - emulsion to a four - necked flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, heat up to 75 - 85 °C, and maintain this temperature;

[0104] S22: Add 1% of initiator into the four - necked flask to initiate the monomer polymerization reaction. The initiator specifically uses ammonium persulfate;

[0105] S23: After a slight reflux phenomenon appears in the reaction system, slowly add the remaining pre - emulsion containing 1% functional monomer into the four - necked flask through the dropping funnel. The dropping time is controlled within 2 - 3 h, and the reaction temperature is kept stable during the dropping process;

[0106] S24: After the dropping is completed, continue the heat - preservation reaction for 1 - 2 h to ensure the full polymerization of monomers, and improve the polymerization degree and stability of the emulsion;

[0107] S3: Neutralization and cross - linking stage

[0108] S31: After the reaction ends, lower the temperature of the reaction system to 40 - 50 °C;

[0109] S32: Slowly add 10% of ammonia water for neutralization, adjust the pH value of the emulsion to 7.5 - 9.0, stir while adding to ensure the full progress of the neutralization reaction;

[0110] S33: Add 1% of cross - linker, continue to stir for 30 - 60 min to make the cross - linker fully react with the functional groups in the emulsion to form a cross - linked structure and improve the emulsion performance;

[0111] S4: Post - treatment stage

[0112] S41: After the stirring ends, filter the emulsion through a 100 - 200 - mesh filter screen to remove the gels and impurities existing in the emulsion, and obtain a pure emulsion for water - based plastic surface printing ink;

[0113] S42: Transfer the filtered emulsion to a clean storage container, seal it, and store it at a temperature controlled between 5 and 30 °C, avoiding direct sunlight and high-temperature environments to ensure the storage stability of the emulsion.

[0114] Experimental Examples

[0115] Take Examples 1 and 2 as Experimental Example 1 and Experimental Example 2 respectively, and a common traditional ink emulsion on the market as Experimental Example 3. Divide them into three groups for experimental treatment. The traditional ink emulsion uses benzene-based organic solvents as the main solvent and a single acrylic resin as the water-based binder.

[0116] 1) Environmental friendliness test

[0117] Use a gas chromatography-mass spectrometry (GC-MS) instrument to determine the types and contents of organic solvents volatilized during the drying process of the two emulsions, and calculate the VOCs emissions.

[0118] 2) Adhesion test

[0119] According to the GB / T 9286-1998 standard, use the cross-cut method to determine the adhesion grade of the ink on the plastic surface.

[0120] 3) Glossiness test

[0121] Use a glossiness meter to measure the glossiness value of the printed matter surface.

[0122] 4) Observation of screen clogging

[0123] During the fine printing process, observe and record the screen clogging situation of the two inks, and count the number of screen clogging times.

[0124] 5) Water resistance test

[0125] Immerse the printed matter in water for 24 hours, and observe the ink peeling and discoloration situations.

[0126] 6) Solvent resistance test

[0127] Use common organic solvents, including ethanol or acetone, to wipe the surface of the printed matter, and observe the ink dissolution and peeling situations.

[0128] 7) Hardness test

[0129] Use a pencil hardness meter to determine the hardness grade of the printed matter surface.

[0130] 8) Printing suitability test

[0131] It includes the wettability, spreadability, ink color uniformity, dot sharpness, etc. of the ink on the plastic surface, and subjective evaluation and objective measurement are carried out through printed samples.

[0132] The above experimental data are as follows:

[0133]

[0134] It can be seen from the above comparative experiments that the emulsion for water-based plastic surface printing ink designed by the present invention is significantly superior to the traditional ink emulsion in terms of environmental protection, adhesion, gloss, screen clogging, water resistance, solvent resistance, hardness and printing suitability, etc.

Claims

1. A water-based plastic surface printing ink emulsion, characterized in that: Calculated by mass percentage, it includes the following components: 40% to 60% of water, 5% to 15% of resin, 1% to 10% of A3 emulsifier, 5% to 10% of ammonia water, 0.5% to 2% of A4 surfactant, 10% to 20% of methyl methacrylate B11, 12% to 30% of octyl acrylate B13, 0.1% to 1% of functional monomer and 0.1% to 1% of cross-linking agent.

2. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: The resin is a compound of any one or more of acrylic resin, polyurethane resin and styrene-acrylic resin, and the compounding ratio ranges from 1:1:1 to 1:3:

2.

3. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: The A3 emulsifier is a compound of a nonionic emulsifier and an anionic emulsifier in a mass ratio of 1:1-2:

1. The anionic emulsifier is specifically any one of sodium dodecylbenzene sulfonate and sodium alkylphenol polyoxyethylene ether sulfate.

4. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: A4 surfactant is a silicone surfactant or a fluorocarbon surfactant.

5. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: The functional monomer is a monomer containing a hydroxyl group, a carboxyl group, or an amino group, specifically any one or more of hydroxyethyl methacrylate, acrylic acid, or methacrylamide. The functional monomer can react with a crosslinking agent to form a crosslinking structure, thereby enhancing the adhesion and abrasion resistance of the ink.

6. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: The crosslinking agent is any one of an aziridine crosslinking agent and a carbodiimide crosslinking agent. The addition of the crosslinking agent enables the emulsion to form a three-dimensional network structure, thereby improving the water resistance, solvent resistance and hardness of the ink.

7. The water-based plastic surface printing ink emulsion according to claim 1, characterized in that: The solid content of the emulsion is 30% to 50%, and the pH value of the emulsion is 7.5-9.

0. Within this pH value range, the emulsion has the best stability and is conducive to the transfer and drying of the ink during the printing process.

8. A method for preparing an emulsion for water-based plastic surface printing ink, characterized in that The method comprises the following steps: S1: Pre-emulsification stage S11: Add 40% to 60% of the formula amount of water into a clean container, turn on the stirring device, and adjust the stirring speed to 200 to 300 r / min; S12: adding 1% to 10% of A3 emulsifier and 0.5% to 2% of A4 surfactant in sequence, stirring evenly to fully dissolve the emulsifier and surfactant in water; S13: slowly add 10% to 20% of methyl methacrylate B11 and 12% to 30% of octyl acrylate B13 to the above solution, continue stirring for 30 to 60 minutes to form a uniform and stable pre-emulsion, and appropriately increase the stirring speed to 300 to 400 r / min during the stirring process to promote the monomers to be fully dispersed in the water phase; S2: Monomer polymerization stage S21: Transfer the pre-emulsion to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, raise the temperature to 75-85° C., and maintain the temperature; S22: adding 0.1% to 1% of an initiator into the four-necked flask to initiate a monomer polymerization reaction; S23: After the reaction system has a slight reflux phenomenon, the remaining pre-emulsified liquid containing 0.1% to 1% of the functional monomer is slowly added to the four-necked flask through a dropping funnel. The dropping time is controlled within 2 to 3 hours. The reaction temperature is kept stable during the dropping process; S24: After the addition is completed, continue to keep the temperature for 1 to 2 hours to ensure that the monomers are fully polymerized and to improve the degree of polymerization and stability of the emulsion; S3: Neutralization and cross-linking stage S31: After the reaction is completed, the temperature of the reaction system is lowered to 40-50° C.; S32: Slowly add 5% to 10% ammonia water for neutralization, adjust the pH value of the emulsion to 7.5-9.0, and stir while adding to ensure that the neutralization reaction is fully carried out; S33: adding 0.1% to 1% of a cross-linking agent, and continuing stirring for 30 to 60 minutes to allow the cross-linking agent to fully react with the functional groups in the emulsion to form a cross-linking structure and improve the performance of the emulsion; S4: Post-processing stage S41: After the stirring is completed, the emulsion is filtered through a 100-200 mesh filter to remove gel and impurities in the emulsion to obtain a pure water-based plastic surface printing ink emulsion; S42: Transfer the filtered emulsion to a clean storage container, seal it and keep it at a temperature between 5 and 30°C. Avoid direct sunlight and high temperature environment to ensure the storage stability of the emulsion.

9. The method for preparing the water-based plastic surface printing ink emulsion according to claim 8, characterized in that: The initiator in step S22 is specifically ammonium persulfate.

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