High-adhesion water-based ink resin emulsion and method for preparing the same

Abstract

The application belongs to the technical field of polymer and functional coating, and discloses a high-adhesion water-based ink resin emulsion and a preparation method thereof.The preparation method comprises the following steps: obtaining a core layer monomer emulsion by emulsifying styrene and (meth) acrylate monomers; obtaining an allyl polyether modified cyclodextrin compound crosslinking agent by performing ring-opening addition reaction on a cyclodextrin compound under alkaline conditions and with an allyl epoxy group terminated polyether; obtaining a shell layer monomer emulsion by emulsifying (meth) acrylate monomers, (meth) acrylic acid monomers and the allyl polyether modified cyclodextrin compound crosslinking agent; and then performing multiple initiation polymerization on the core layer monomer emulsion and the shell layer monomer emulsion to obtain the high-adhesion water-based ink resin emulsion.The water-based ink resin emulsion is crosslinked and modified by using a specific cyclodextrin compound crosslinking agent, has significantly improved adhesion and water resistance, and can improve the tinting strength of the obtained water-based ink.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymers and functional coatings, and particularly relates to a high-adhesion water-ink resin emulsion and a preparation method thereof. BACKGROUND

[0002] The ink binder, also known as ink additive, is an important component of printing ink and is the fluid part of the ink. The rheological property, viscosity, drying property, film-forming property and printing performance of the printing ink mainly depend on the binder. The solid components in the ink can be finely ground in the manufacturing process by the wetting action of the binder, the transfer and transfer in the printing process are completed by the viscosity, and the ink film is protected by the binder to form a glossy and firm ink mark on the printed matter. The quality of water-based ink mainly depends on the quality of its binder. At present, acrylic resin emulsion is widely used as a binder in the production of water-based ink due to its high stability, good gloss, good weather resistance and good rheological property. The acrylic resin mainly improves the adhesion on substrates such as polyethylene (PE) and polyester (PET) through polar groups, but the polar groups generally have strong hydrophilicity, resulting in insufficient water resistance of the prepared ink coating.

[0003] In our previous patent CN113292682A, a modified macromonomer with a specific structure was used as a shell polymerization monomer. The long-chain polyoxyethylene ether structure can significantly improve the dispersibility and leveling and wetting properties of water-based ink and water-based latex paint; the silane coupling agent structure can impart the product with room temperature crosslinking characteristics and enhanced adhesion, making the ink or coating film more dense and enhancing the scratch resistance, water resistance and medium resistance. However, in actual application, it was found that although the introduction of the silane coupling agent structure with room temperature self-crosslinking can significantly improve the film performance and adhesion, there is still a certain degree of self-aggregation and crosslinking during long-term storage, resulting in poor storage stability of the product. In addition, the preparation process of the modified macromonomer requires a large amount of organic solvent, which has poor environmental friendliness.

[0004] Therefore, it is necessary to provide a water-ink resin emulsion that can simultaneously enhance adhesion, water resistance and stability, so as to be applied in different application scenarios. SUMMARY

[0005] In view of the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a preparation method of a high-adhesion water-ink resin emulsion.

[0006] Another purpose of the present application is to provide a high-adhesion water-ink resin emulsion prepared by the above method.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A preparation method of a high-adhesion water-based ink resin emulsion, comprising the following preparation steps:

[0009] (1) Preparation of core layer monomer emulsion: styrene, (meth)acrylate monomer and emulsifier are added to deionized water for stirring and emulsification to obtain the core layer monomer emulsion;

[0010] (2) Preparation of cyclodextrin compound crosslinking agent: the cyclodextrin compound is dissolved in an alkaline aqueous solution by heating, and then allyl epoxy-terminated polyether is added, and the reaction is carried out at 60-90℃ to obtain an allyl polyether modified cyclodextrin compound crosslinking agent;

[0011] (3) Preparation of shell layer monomer emulsion: (meth)acrylate monomer, (meth)acrylic acid monomer, allyl polyether modified cyclodextrin compound crosslinking agent and emulsifier are added to deionized water for stirring and emulsification to obtain the shell layer monomer emulsion;

[0012] (4) Preparation of resin emulsion: the core layer monomer emulsion is heated to 55-85℃, and then an initiator solution is added for polymerization to obtain the core layer emulsion; the shell layer monomer emulsion and the initiator solution are added dropwise for further polymerization to obtain the high-adhesion water-based ink resin emulsion.

[0013] Further, the (meth)acrylate monomer in steps (1) and (3) is at least one selected from methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate and isooctyl methacrylate.

[0014] Further, the mass percentage of the styrene and the (meth)acrylate monomer in step (1) is 15-30% for the styrene and 70-85% for the (meth)acrylate monomer.

[0015] Further, the emulsifier in steps (1) and (3) is at least one selected from sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), sodium fatty alcohol polyoxyethylene ether sulfate (AES), fatty alcohol polyoxyethylene ether (AEO) and alkyl phenol polyoxyethylene ether (APEO).

[0016] Further, the cyclodextrin compound in step (2) is any one selected from cyclodextrin (including α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin), hydroxyethyl cyclodextrin, hydroxypropyl cyclodextrin, carboxymethyl cyclodextrin and aminocyclodextrin.

[0017] Further, the alkaline aqueous solution in step (2) is a sodium hydroxide solution with a mass fraction of 0.5-5%.

[0018] Furthermore, the molecular weight of the allyl epoxy-terminated polyether in step (2) is 200 to 800; the molar ratio of the allyl epoxy-terminated polyether to the cyclodextrin compound is 2 to 7:1.

[0019] Furthermore, the mass percentages of the (meth)acrylate monomer, (meth)acrylic acid monomer, and allyl polyether modified cyclodextrin compound crosslinker added in step (3) are: 30% to 60% of the (meth)acrylate monomer, 20% to 40% of the (meth)acrylic acid monomer, and 10% to 50% of the allyl polyether modified cyclodextrin compound crosslinker.

[0020] Furthermore, the initiator in step (4) is selected from at least one of ammonium persulfate (APS) and potassium persulfate (KPS).

[0021] Furthermore, in step (4), the solid content of the core layer monomer emulsion is 35% to 60%, the solid content of the shell layer monomer emulsion is 35% to 60%, and the mass ratio of the core layer monomer emulsion to the shell layer monomer emulsion is 1:0.5 to 2.

[0022] A high-adhesion ink resin emulsion is prepared by the method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The ink resin emulsion of the present invention is prepared by multiple cross-linking polymerization using a variety of acrylic ester monomers and functional monomers as main raw materials, and has excellent adhesion to films and chemical and physical resistance.

[0025] (2) The ink resin emulsion of the present invention is cross-linked and modified using a specific cyclodextrin compound cross-linking agent, which can significantly improve the cohesive strength of the polymer and improve the water resistance of the coating; at the same time, the cyclodextrin compound cross-linking unit can provide a large number of polar groups, which has good dispersibility and binding force on the water-based ink color paste and good binding force on the substrate, and can significantly improve the tinting power of the resulting water-based ink and improve the adhesion of the coating. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0027] Example 1

[0028] A method for preparing a high-adhesion ink resin emulsion comprises the following steps:

[0029] (1) Preparation of core layer monomer emulsion: Weigh each raw material by mass, add 20 parts of styrene, 60 parts of methyl methacrylate, 20 parts of butyl methacrylate and 8 parts of emulsifier AEO into 120 parts of deionized water, stir and emulsify, and obtain core layer monomer emulsion.

[0030] (2) Preparation of a cyclodextrin compound crosslinker: 113.5 parts of β-cyclodextrin were heated and dissolved in a 2% by mass sodium hydroxide aqueous solution, and then 150 parts of an allyl epoxy-terminated polyether with a molecular weight of 500 were added. The mixture was heated to 75°C and kept warm for 2 hours to carry out a ring-opening reaction to obtain an allyl polyether-modified cyclodextrin compound crosslinker.

[0031] (3) Preparation of shell monomer emulsion: 40 parts of methyl methacrylate, 30 parts of methacrylic acid, 30 parts of allyl polyether modified cyclodextrin compound crosslinker and 4 parts of emulsifier AEO were added to 120 parts of deionized water and stirred and emulsified to obtain shell monomer emulsion.

[0032] (4) Preparation of resin emulsion: The core layer monomer emulsion is heated to 75°C, and then the initiator APS solution is added to carry out polymerization reaction for 2 hours to obtain the core layer emulsion; the shell layer monomer emulsion and the initiator APS solution are then added dropwise to continue the polymerization reaction. The dropping time of the shell layer monomer emulsion is 1.5 hours, and the dropping time of the initiator solution is 0.5 hours. After the shell layer monomer emulsion is added, the reaction is continued at the same temperature for 2 hours to obtain a high-adhesion ink resin emulsion.

[0033] Example 2

[0034] A method for preparing a high-adhesion ink resin emulsion comprises the following steps:

[0035] (1) Preparation of core layer monomer emulsion: Weigh each raw material by mass, add 15 parts of styrene, 60 parts of methyl methacrylate, 25 parts of isooctyl acrylate and 6 parts of emulsifier AEO into 120 parts of deionized water, stir and emulsify, and obtain core layer monomer emulsion.

[0036] (2) Preparation of a cyclodextrin compound crosslinker: 144.3 parts of hydroxyethyl-β-cyclodextrin were heated and dissolved in a 1% by mass sodium hydroxide aqueous solution, and then 40 parts of an allyl epoxy-terminated polyether with a molecular weight of 200 were added. The mixture was heated to 75°C and kept warm for 2 hours to carry out a ring-opening reaction to obtain an allyl polyether-modified cyclodextrin compound crosslinker.

[0037] (3) Preparation of shell monomer emulsion: 60 parts of ethyl methacrylate, 20 parts of methacrylic acid, 20 parts of allyl polyether modified cyclodextrin compound crosslinker and 4 parts of emulsifier AEO were added to 120 parts of deionized water and stirred and emulsified to obtain shell monomer emulsion.

[0038] (4) Preparation of resin emulsion: The core layer monomer emulsion is heated to 75°C, and then the initiator APS solution is added to carry out polymerization reaction for 2 hours to obtain the core layer emulsion; the shell layer monomer emulsion and the initiator APS solution are then added dropwise to continue the polymerization reaction. The dropping time of the shell layer monomer emulsion is 1.5 hours, and the dropping time of the initiator solution is 0.5 hours. After the shell layer monomer emulsion is added, the reaction is continued at the same temperature for 2 hours to obtain a high-adhesion ink resin emulsion.

[0039] Example 3

[0040] A method for preparing a high-adhesion ink resin emulsion comprises the following steps:

[0041] (1) Preparation of core layer monomer emulsion: Weigh each raw material by mass, add 30 parts of styrene, 40 parts of ethyl methacrylate, 30 parts of butyl acrylate and 10 parts of emulsifier AEO to 120 parts of deionized water, stir and emulsify, and obtain core layer monomer emulsion.

[0042] (2) Preparation of a cyclodextrin compound crosslinker: 154.2 parts of hydroxypropyl-β-cyclodextrin were heated and dissolved in a 0.5% by mass sodium hydroxide aqueous solution, and then 400 parts of an allyl epoxy-terminated polyether with a molecular weight of 800 were added. The mixture was heated to 75°C and kept warm for 2 hours to perform a ring-opening reaction to obtain an allyl polyether-modified cyclodextrin compound crosslinker.

[0043] (3) Preparation of shell monomer emulsion: 50 parts of butyl methacrylate, 40 parts of methacrylic acid, 10 parts of allyl polyether modified cyclodextrin compound crosslinker and 5 parts of emulsifier AEO were added to 120 parts of deionized water and stirred and emulsified to obtain shell monomer emulsion.

[0044] (4) Preparation of resin emulsion: The core layer monomer emulsion is heated to 75°C, and then the initiator APS solution is added to carry out polymerization reaction for 2 hours to obtain the core layer emulsion; the shell layer monomer emulsion and the initiator APS solution are then added dropwise to continue the polymerization reaction. The dropping time of the shell layer monomer emulsion is 1.5 hours, and the dropping time of the initiator solution is 0.5 hours. After the shell layer monomer emulsion is added, the reaction is continued at the same temperature for 2 hours to obtain a high-adhesion ink resin emulsion.

[0045] Comparative Example 1

[0046] A method for preparing a high-adhesion ink resin emulsion, compared with Example 1, wherein no allyl polyether-modified cyclodextrin compound cross-linking agent is added to the shell monomer emulsion, comprises the following preparation steps:

[0047] (1) The preparation of the core layer monomer emulsion is the same as in Example 1.

[0048] (2) Preparation of shell monomer emulsion: 40 parts of methyl methacrylate, 30 parts of methacrylic acid and 4 parts of emulsifier AEO were added to 120 parts of deionized water and stirred and emulsified to obtain a shell monomer emulsion.

[0049] (3) Preparation of resin emulsion: The core layer monomer emulsion is heated to 75°C, and then the initiator APS solution is added to carry out polymerization reaction for 2 hours to obtain the core layer emulsion; then the shell layer monomer emulsion and the initiator APS solution are added dropwise to continue the polymerization reaction. The dropping time of the shell layer monomer emulsion is 1.5 hours, and the dropping time of the initiator solution is 0.5 hours. After the shell layer monomer emulsion is added, the reaction is continued at the temperature for 2 hours to obtain a high-adhesion ink resin emulsion.

[0050] Comparative Example 2

[0051] A method for preparing a high-adhesion water-based ink resin emulsion, compared with Example 1, uses an equal amount of pentaerythritol triacrylate crosslinking agent instead of an allyl polyether modified cyclodextrin compound crosslinking agent, and the rest are the same.

[0052] The performance of the ink resin emulsions obtained in the above examples and comparative examples in the production of water-based inks was tested. One part of the ink resin emulsion was added to one part of the aqueous color paste and dispersed evenly. The mixture was then applied to a PE film and dried to cure. Adhesion fastness was tested according to GB / T 13217.7-2023. Water resistance was tested by immersing the film in 48°C warm water for 48 hours and then drying it at 80°C before testing adhesion fastness. Tinting strength was tested according to GB / T 13217.6-2008. The test results are shown in Table 1 below.

[0053] Table 1

[0054] Test sample adhesion water resistance coloring power Example 1 100％ 94％ 102％ Example 2 97％ 90％ 99％ Example 3 96％ 87％ 97％ Comparative Example 1 85％ 61％ 92％ Comparative Example 2 88％ 80％ 86％

[0055] Comparisons of Examples 1-3 with Comparative Example 1 in Table 1 demonstrate that crosslinking and modification of the shell emulsion of the present invention with a specific cyclodextrin compound crosslinker significantly improves the adhesion, water resistance, and tinting strength of the resulting water-based ink coating. Comparisons of Example 1 with Comparative Examples 1 and 2 demonstrate that the use of a conventional pentaerythritol triacrylate crosslinker adversely affects the tinting strength of the resulting water-based ink coating and does not significantly improve adhesion. This is because a high content of pentaerythritol triacrylate crosslinker results in an excessively high crosslink density, resulting in excessive embedding of polar groups, which impairs the resin emulsion's binding and dispersibility to the color paste and reduces its bonding to the substrate film.

[0056] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a high-adhesion ink resin emulsion, characterized in that: The method comprises the following preparation steps: (1) Preparation of core layer monomer emulsion: Styrene, (meth)acrylate monomer and emulsifier are added to deionized water and stirred and emulsified to obtain core layer monomer emulsion; (2) Preparation of a cyclodextrin compound crosslinker: dissolving a cyclodextrin compound in an alkaline aqueous solution by heating, then adding an allyl epoxy-terminated polyether, and reacting at 60-90° C. to obtain an allyl polyether-modified cyclodextrin compound crosslinker; (3) Preparation of shell monomer emulsion: adding (meth)acrylate monomer, (meth)acrylic acid monomer, allyl polyether modified cyclodextrin compound crosslinker and emulsifier into deionized water and stirring and emulsifying to obtain shell monomer emulsion; (4) Preparation of resin emulsion: The core layer monomer emulsion is heated to 55-85°C, and then an initiator solution is added to carry out polymerization reaction to obtain a core layer emulsion; the shell layer monomer emulsion and the initiator solution are then added dropwise to continue the polymerization reaction to obtain a high-adhesion ink resin emulsion.

2. The method for preparing a high-adhesion ink resin emulsion according to claim 1, wherein: The (meth)acrylate monomer in steps (1) and (3) is at least one selected from methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, and isooctyl methacrylate.

3. The method for preparing a high-adhesion ink resin emulsion according to claim 1, wherein: The mass percentages of styrene and (meth)acrylate monomers in step (1) are: styrene 15% to 30%, (meth)acrylate monomers 70% to 85%.

4. The method for preparing a high-adhesion ink resin emulsion according to claim 1, wherein: The emulsifier in steps (1) and (3) is at least one selected from sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

5. The method for preparing a high-adhesion ink resin emulsion according to claim 1, wherein: The cyclodextrin compound in step (2) is selected from any one of cyclodextrin, hydroxyethyl cyclodextrin, hydroxypropyl cyclodextrin, carboxymethyl cyclodextrin, and amino cyclodextrin; the alkaline aqueous solution refers to a sodium hydroxide solution with a mass fraction of 0.5 to 5%.

6. The method for preparing a high-adhesion ink resin emulsion according to claim 1, characterized in that: The molecular weight of the allyl epoxy-terminated polyether in step (2) is 200-800; the molar ratio of the allyl epoxy-terminated polyether to the cyclodextrin compound is 2-7:

1.

7. The method for preparing a high-adhesion ink resin emulsion according to claim 1, characterized in that: The mass percentages of the (meth)acrylate monomer, (meth)acrylic acid monomer, and allyl polyether modified cyclodextrin compound crosslinking agent added in step (3) are: 30% to 60% of the (meth)acrylate monomer, 20% to 40% of the (meth)acrylic acid monomer, and 10% to 50% of the allyl polyether modified cyclodextrin compound crosslinking agent.

8. The method for preparing a high-adhesion ink resin emulsion according to claim 1, characterized in that: The initiator in step (4) is selected from at least one of ammonium persulfate and potassium persulfate.

9. The method for preparing a high-adhesion ink resin emulsion according to claim 1, characterized in that: In step (4), the solid content of the core layer monomer emulsion is 35% to 60%, the solid content of the shell layer monomer emulsion is 35% to 60%, and the mass ratio of the core layer monomer emulsion to the shell layer monomer emulsion is 1:0.5 to 2.

10. A high-adhesion ink resin emulsion, characterized in that: It is prepared by the method according to any one of claims 1 to 9.