Water-based acrylic emulsion and preparation method thereof

Abstract

The invention provides a water-based acrylic emulsion and a preparation method thereof, and belongs to the technical field of printing. The water-based acrylic emulsion prepared by the invention is prepared from the following components in parts by mass: 20 to 40 parts of methyl methacrylate, 5 to 10 parts of acrylic acid, 10 to 20 parts of hydroxyethyl acrylate, 20 to 30 parts of epoxy acrylic acid, 2 to 8 parts of styrene, 0.5 to 2 parts of a coalescing agent, 0.05 to 0.3 part of an emulsifier, 0.2 to 0.4 part of an initiator, 0.5 to 3 parts of a salt-resistant additive and 20 to 50 parts of deionized water. By adjusting the components of the acrylic emulsion, adopting multiple monomers for polymerization and adding the auxiliaries, the polymerization speed and performance of the emulsion are improved, water-based ink is prepared from the prepared water-based acrylic emulsion, and the stability, adhesive force and salt resistance of the ink can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of printing, and in particular to a water-based acrylic emulsion and a preparation method thereof. Background Art

[0002] As a material used to form graphic information, ink is extremely important in the printing industry and can directly determine whether the color and clarity of the image on the printed product have a good effect. Printing ink can be divided into letterpress ink, lithographic ink, gravure printing ink and mesh ink. The components of ink are generally colorants, binders, fillers, etc. Among them, the colorant gives the printed product a variety of tones, the binder can make the colorant adhere to the surface of the substrate, and the filler can give the ink appropriate properties, so that the ink meets the printing applicability of various printing processes.

[0003] With the continuous improvement of people's living standards, environmental protection and greenness have become the general trend of the printing and packaging industry today. Compared with organic solvent-based inks, water-based inks with water as the solvent are widely used because of their extremely low VOC content and the advantages of significantly reducing the harm to ink users. Water-based inks, also known as liquid inks, are mainly made of water-soluble resins, organic pigments, solvents and related additives through composite grinding. Water-based inks are particularly suitable for packaging and printing products with strict hygiene requirements such as tobacco, alcohol, food, beverages, medicines, and children's toys.

[0004] Water-based acrylic emulsions use water as the main solvent and have the characteristics of low VOC content. They have good stain resistance, scrub resistance, light resistance, acid and alkali resistance, and have been widely used in the printing field. However, the water-based acrylic emulsions used in the printing field in the prior art have the disadvantages of poor adhesion and stability, and are easy to fall off from objects. They are not suitable for high temperature and high salinity environments, and are prone to deformation and discoloration at high temperatures and high salinity.

[0005] Chinese patent CN116790153B discloses a moisture-proof ink for corrugated cardboard, which is divided into component A, component B and component C; calculated by weight, the component A is 1-3 parts of cross-linking monomer a, 5-8 parts of solvent and 0.05-0.08 parts of oxidant; the component B is 1-3 parts of cross-linking monomer b, 5-8 parts of solvent, 0.05-0.08 parts of reducing agent and 7-10 parts of water; the component C is 10-15 parts of cross-linking monomer c, 5-8 parts of pigment, 10-15 parts of water-based acrylic emulsion and 7-10 parts of water. This patent uses the existing water-based acrylic emulsion as raw material, and generates an organic film by polymerization with other monomers to improve the acid and alkali resistance and moisture resistance of the ink.

[0006] Chinese patent CN117866481B discloses a highly adhesive water-based printing ink and a preparation method thereof, wherein the ink comprises the following components: 100 parts of water-based acrylic emulsion, 14-28 parts of pigment, 5-10 parts of modifier, 1.2-2.4 parts of dispersant, 0.7-1.4 parts of defoamer, 1.5-3 parts of wetting agent, 1-2 parts of thickener and 20-30 parts of deionized water. This patent uses the existing water-based acrylic emulsion as raw material, and improves the adhesion and high temperature stability of the ink by modifying it with a modifier.

[0007] Although the above method solves the problems of water-based ink to a certain extent, the ink preparation process is complicated. Therefore, it is an urgent problem to improve the water-based acrylic emulsion so that it can directly prepare water-based ink with good stability and adhesion and simplify the preparation process of water-based ink. Summary of the invention

[0008] In view of this, the object of the present invention is to provide an aqueous acrylic emulsion for use in the printing field, which can improve the stability and adhesion of ink.

[0009] In order to solve the above-mentioned purpose, the present invention provides an aqueous acrylic emulsion, comprising the following components in parts by weight: 20-40 parts of methyl methacrylate, 5-10 parts of acrylic acid, 10-20 parts of hydroxyethyl acrylate, 20-30 parts of epoxy acrylate, 2-8 parts of styrene, 0.5-2 parts of a film-forming aid, 0.05-0.3 parts of an emulsifier, 0.2-0.4 parts of an initiator, 0.5-3 parts of a salt-resistant aid, and 20-50 parts of deionized water.

[0010] Preferably, the aqueous acrylic emulsion comprises the following components in parts by mass: 30 parts of methyl methacrylate, 6 parts of acrylic acid, 13 parts of hydroxyethyl acrylate, 25 parts of epoxy acrylate, 5 parts of styrene, 0.8 parts of film-forming aid, 0.12 parts of emulsifier, 0.3 parts of initiator, 1.1 parts of salt-resistant aid, and 40 parts of deionized water.

[0011] Preferably, the film-forming aid is at least one of alcohol ester dodecanedione, dipropylene glycol monomethyl ether and dipropylene glycol monobutyl ether.

[0012] Preferably, the emulsifier is at least one of sodium dodecyl sulfate and sodium dodecyl sulfonate.

[0013] Preferably, the initiator is any one of potassium persulfate and sodium persulfate.

[0014] Preferably, the salt-resistant additive is aluminum tripolyphosphate.

[0015] Another object of the present invention is to provide a method for preparing an aqueous acrylic emulsion, the preparation method comprising the following steps:

[0016] (1) Weighing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylic acid, styrene, film-forming aid, emulsifier, initiator, salt-resistant aid and deionized water in proportion;

[0017] (2) mixing an emulsifier and deionized water to obtain an emulsifier solution;

[0018] (3) mixing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylate and styrene to obtain a mixed monomer;

[0019] (4) taking part of the emulsifier solution prepared in step (2) and mixing it with the mixed monomer prepared in step (3) to obtain an emulsified monomer;

[0020] (5) The temperature of the emulsified monomers in step (4) is raised, an initiator is added, the mixture is kept warm and stirred evenly, and then the remaining emulsifier solution and other raw materials are added, and the mixture is mixed evenly to obtain the aqueous acrylic emulsion.

[0021] Preferably, the mass ratio of the emulsifier solution to the mixed monomer in step (4) is 1-1.5:30-50.

[0022] Preferably, the heating temperature in step (5) is 60-70°C.

[0023] Preferably, the insulation temperature in step (5) is 60-70° C., and the insulation time is 20-40 min.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The invention provides an aqueous acrylic emulsion and a preparation method thereof. By adjusting the components of the acrylic emulsion, polymerizing multiple monomers, and adding an auxiliary agent to improve the polymerization speed and performance of the emulsion, the aqueous acrylic emulsion prepared by the invention is used to prepare aqueous ink, thereby improving the stability, adhesion and salt resistance of the ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of the preparation method of the aqueous acrylic emulsion. DETAILED DESCRIPTION

[0027] The invention provides an aqueous acrylic emulsion, which is composed of the following components in parts by mass: 20-40 parts of methyl methacrylate, 5-10 parts of acrylic acid, 10-20 parts of hydroxyethyl acrylate, 20-30 parts of epoxy acrylate, 2-8 parts of styrene, 0.5-2 parts of a film-forming aid, 0.05-0.3 parts of an emulsifier, 0.2-0.4 parts of an initiator, 0.5-3 parts of a salt-resistant aid, and 20-50 parts of deionized water.

[0028] In a specific embodiment of the present invention, the aqueous acrylic emulsion is composed of the following components in parts by mass: 30 parts of methyl methacrylate, 6 parts of acrylic acid, 13 parts of hydroxyethyl acrylate, 25 parts of epoxy acrylate, 5 parts of styrene, 0.8 parts of film-forming aid, 0.12 parts of emulsifier, 0.3 parts of initiator, 1.1 parts of salt-resistant aid, and 40 parts of deionized water.

[0029] Preferably, the film-forming aid is at least one of alcohol ester dodecahydrate, dipropylene glycol monomethyl ether, and dipropylene glycol monobutyl ether; more preferably, the film-forming aid is formed by mixing alcohol ester dodecahydrate and dipropylene glycol monomethyl ether in a mass ratio of 1:2; or the film-forming aid is formed by mixing alcohol ester dodecahydrate and dipropylene glycol monomethyl ether in a mass ratio of 1:1; or the film-forming aid is formed by mixing alcohol ester dodecahydrate and dipropylene glycol monobutyl ether in a mass ratio of 1:1.

[0030] Preferably, the emulsifier is at least one of sodium dodecyl sulfate and sodium dodecyl sulfonate; more preferably, the emulsifier is sodium dodecyl sulfate.

[0031] Preferably, the initiator is any one of potassium persulfate and sodium persulfate; more preferably, the initiator is potassium persulfate.

[0032] Preferably, the salt-resistant additive is aluminum tripolyphosphate.

[0033] Another object of the present invention is to provide a method for preparing an aqueous acrylic emulsion, the preparation method comprising the following steps:

[0034] (1) Weighing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylic acid, styrene, film-forming aid, emulsifier, initiator, salt-resistant aid and deionized water in proportion;

[0035] (2) mixing an emulsifier and deionized water to obtain an emulsifier solution;

[0036] (3) mixing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylate and styrene to obtain a mixed monomer;

[0037] (4) taking part of the emulsifier solution prepared in step (2) and mixing it with the mixed monomer prepared in step (3) to obtain an emulsified monomer;

[0038] (5) The temperature of the emulsified monomers in step (4) is raised, an initiator is added, the mixture is kept warm and stirred evenly, and then the remaining emulsifier solution and other raw materials are added, and the mixture is mixed evenly to obtain the aqueous acrylic emulsion.

[0039] The preparation method flow chart of the aqueous acrylic emulsion of the present invention is as follows Figure 1 .

[0040] In a specific embodiment of the present invention, the mass ratio of the emulsifier solution to the mixed monomer in step (4) is 1-1.5:30-50.

[0041] In a specific embodiment of the present invention, the temperature of the heating in step (5) is 60-70°C.

[0042] In a specific embodiment of the present invention, the insulation temperature in step (5) is 60-70° C., and the insulation time is 20-40 min.

[0043] The present invention is further described below in conjunction with examples. In the specific examples of the present invention, unless otherwise specified, the experimental methods or test methods are all conventional methods; the raw materials and additives are all obtained from conventional commercial channels or prepared by conventional methods; the addition amounts of the raw materials are all by mass; and the ratios are all by mass ratios.

[0044] Embodiments 1 to 5

[0045] A water-based acrylic emulsion, the raw material composition (mass fraction) is shown in Table 1.

[0046] The preparation method of the aqueous acrylic emulsion comprises the following steps:

[0047] (1) Weighing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylic acid, styrene, film-forming aid, emulsifier, initiator, salt-resistant aid and deionized water in proportion;

[0048] (2) mixing an emulsifier and deionized water to obtain an emulsifier solution;

[0049] (3) mixing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylate and styrene to obtain a mixed monomer;

[0050] (4) taking part of the emulsifier solution prepared in step (2) and mixing it with the mixed monomer prepared in step (3) to obtain an emulsified monomer; wherein the mass ratio of the emulsifier solution to the mixed monomer is 1:40.

[0051] (5) The temperature of the emulsified monomers in step (4) is raised to 65° C., an initiator is added, and the mixture is kept at 65° C. for 30 min and stirred evenly. Then, the remaining emulsifier solution and other raw materials are added and mixed evenly to obtain the aqueous acrylic emulsion.

[0052] Comparative Examples 1-5

[0053] The raw material composition of the aqueous acrylic emulsion was changed to prepare the aqueous acrylic emulsion. The raw material composition (mass fraction) is shown in Table 2.

[0054] Table 1

[0055]

[0056] Table 2

[0057]

[0058]

[0059] The performance of the aqueous acrylic emulsion prepared in Examples 1 to 5 was tested. The specific method was as follows: 45 parts by weight of the aqueous acrylic emulsion, 20 parts by weight of a pigment (white pigment MR-939A rutile titanium dioxide (P.W6)), and 35 parts by weight of 75% alcohol were mixed and shaken for 3 hours to prepare a water-based ink, which was then tested.

[0060] Viscosity test reference: GB / T 13217.4-2020 "Ink viscosity test method";

[0061] Initial drying test reference: GB / T13217.5-2008 "Initial drying test method for liquid ink";

[0062] Adhesion fastness (coated paper) test reference: GB / T 13217.7-2009 "Test method for adhesion fastness of liquid ink"; 25℃ refers to the test results under the conditions of temperature 25℃ and humidity 65%; 60℃ refers to the test results under the conditions of temperature 60℃ and humidity 65%;

[0063] Salt water resistance test: Using PE film as the substrate, the film with ink attached is placed in NaCl solutions of different concentrations to test the durability, corrosion resistance and stability of the ink in a salt water environment.

[0064] The test results of Examples 1 to 5 are shown in Table 3:

[0065] Table 3

[0066]

[0067] The test results of Comparative Examples 1 to 5 are shown in Table 4:

[0068] Table 4

[0069]

[0070] 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 water-based acrylic emulsion, characterized in that: The invention comprises the following components in parts by weight: 20-40 parts of methyl methacrylate, 5-10 parts of acrylic acid, 10-20 parts of hydroxyethyl acrylate, 20-30 parts of epoxy acrylate, 2-8 parts of styrene, 0.5-2 parts of film-forming aid, 0.05-0.3 parts of emulsifier, 0.2-0.4 parts of initiator, 0.5-3 parts of salt-resistant aid and 20-50 parts of deionized water.

2. A water-based acrylic emulsion according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 30 parts of methyl methacrylate, 6 parts of acrylic acid, 13 parts of hydroxyethyl acrylate, 25 parts of epoxy acrylate, 5 parts of styrene, 0.8 parts of film-forming aid, 0.12 parts of emulsifier, 0.3 parts of initiator, 1.1 parts of salt-resistant aid and 40 parts of deionized water.

3. A water-based acrylic emulsion according to claim 1, characterized in that: The film-forming aid is at least one of alcohol ester dodecanedione, dipropylene glycol monomethyl ether and dipropylene glycol monobutyl ether.

4. A water-based acrylic emulsion according to claim 1, characterized in that: The emulsifier is at least one of sodium lauryl sulfate and sodium lauryl sulfonate.

5. A water-based acrylic emulsion according to claim 1, characterized in that: The initiator is any one of potassium persulfate and sodium persulfate.

6. A water-based acrylic emulsion according to claim 1, characterized in that: The salt-resistant additive is aluminum tripolyphosphate.

7. The method for preparing the aqueous acrylic emulsion according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Weighing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylic acid, styrene, film-forming aid, emulsifier, initiator, salt-resistant aid and deionized water in proportion; (2) mixing an emulsifier and deionized water to obtain an emulsifier solution; (3) mixing methyl methacrylate, acrylic acid, hydroxyethyl acrylate, epoxy acrylate and styrene to obtain a mixed monomer; (4) taking part of the emulsifier solution prepared in step (2) and mixing it with the mixed monomer prepared in step (3) to obtain an emulsified monomer; (5) The temperature of the emulsified monomers in step (4) is raised, an initiator is added, the mixture is kept warm and stirred evenly, and then the remaining emulsifier solution and other raw materials are added, and the mixture is mixed evenly to obtain the aqueous acrylic emulsion.

8. The method for preparing the aqueous acrylic emulsion according to claim 7, characterized in that: The mass ratio of the emulsifier solution to the mixed monomer in step (4) is 1-1.5:30-50.

9. The method for preparing the aqueous acrylic emulsion according to claim 7, characterized in that: The temperature of the heating in step (5) is 60-70°C.

10. The method for preparing the aqueous acrylic emulsion according to claim 7, characterized in that: The insulation temperature in step (5) is 60-70° C. and the insulation time is 20-40 min.

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