High-adhesion water-based ink resin emulsion and preparation method thereof

Abstract

The invention belongs to the technical field of polymers and functional coatings, and discloses a high-adhesion water-based ink resin emulsion and a preparation method thereof. The preparation method comprises the following steps: emulsifying styrene and (methyl) acrylate monomers to obtain a core layer monomer emulsion; the preparation method comprises the following steps: carrying out ring-opening addition reaction on a cyclodextrin compound and allyl epoxy-terminated polyether under an alkaline condition to obtain an allyl polyether modified cyclodextrin compound cross-linking agent; emulsifying a (methyl) acrylate monomer, a (methyl) acrylic acid monomer and an allyl polyether modified cyclodextrin compound cross-linking agent to obtain a shell layer monomer emulsion; and carrying out 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 disclosed by the invention is subjected to crosslinking modification by adopting a specific cyclodextrin compound crosslinking agent, so that the adhesive force and the water resistance are remarkably improved, and the tinting strength of the obtained water-based ink can be improved.

Description

Technical Field

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

[0002] Ink binder, also known as ink additive, is an important component of printing ink and the fluid part of ink. The rheology, viscosity, drying, film-forming and printing performance of printing ink mainly depend on the binder. The solid components in the ink can be ground into powder during the manufacturing process by relying on the wetting effect of the binder, and the transfer during the printing process can be completed by relying on its viscosity. On the printed matter, the drying film-forming property of the binder makes the print form a glossy and fast ink film to protect the pigment. 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 advantages such as high stability, good gloss, good weather resistance and good rheological properties. Acrylic resin mainly improves the adhesion on substrates such as polyethylene (PE) and polyester (PET) through polar groups, but the polar groups are generally highly hydrophilic, resulting in insufficient water resistance of the prepared ink coating.

[0003] In our previous patent CN113292682A, a modified macromonomer with a specific structure is used as a shell polymerization monomer, in which the long-chain polyoxyethylene ether structure can significantly improve the dispersibility and leveling wettability of water-based inks and water-based latex paints; the silane coupling agent structure can give the product room-temperature cross-linking characteristics and enhance adhesion, making the ink or coating film more dense, and enhancing scratch resistance, water resistance, and medium resistance. However, in the actual application process, it was found that although the introduction of a silane coupling agent structure with room-temperature self-crosslinking can significantly improve the coating performance and adhesion, there is also a certain degree of self-polymerization and cross-linking during long-term storage, resulting in a deterioration in the storage stability of the product. In addition, the amount of organic solvent used in the preparation process of the modified macromonomer is relatively large, and the environmental protection is slightly poor.

[0004] Therefore, it is necessary to provide an ink resin emulsion that can simultaneously enhance adhesion, water resistance and stability so as to be applied to application scenarios with different requirements. Summary of the invention

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

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

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a high-adhesion ink resin emulsion comprises the following preparation steps:

[0009] (1) Preparation of core layer monomer emulsion: adding styrene, (meth)acrylate monomer and emulsifier into deionized water and stirring and emulsifying to obtain core layer monomer emulsion;

[0010] (2) Preparation of a cyclodextrin compound crosslinking agent: heating a cyclodextrin compound to dissolve it in an alkaline aqueous solution, then adding an allyl epoxy-terminated polyether, and reacting at 60 to 90° C. to obtain an allyl polyether-modified cyclodextrin compound crosslinking agent;

[0011] (3) Preparation of shell monomer emulsion: adding (meth)acrylate monomer, (meth)acrylic acid monomer, allyl polyether modified cyclodextrin compound crosslinking agent and emulsifier into deionized water, stirring and emulsifying, to obtain shell monomer emulsion;

[0012] (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; and then the shell layer monomer emulsion and the initiator solution are added dropwise to continue the polymerization reaction to obtain a high-adhesion ink resin emulsion.

[0013] Furthermore, 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] Furthermore, the mass percentages of styrene and (meth)acrylate monomers in step (1) are: styrene 15% to 30% and (meth)acrylate monomers 70% to 85%.

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

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

[0017] Furthermore, the alkaline aqueous solution in step (2) refers to a sodium hydroxide solution with a mass fraction of 0.5 to 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 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.

[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 thin 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 for the water-based ink color paste and good binding force for 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 is further described in detail below in conjunction with 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 preparation 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 cyclodextrin compound crosslinking agent: 113.5 parts of β-cyclodextrin were heated and dissolved in a 2% sodium hydroxide aqueous solution, and then 150 parts of allyl epoxy-terminated polyether with a molecular weight of 500 were added, and 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 crosslinking agent.

[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 crosslinking agent and 4 parts of emulsifier AEO were added to 120 parts of deionized water and stirred for emulsification to obtain a 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; 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 by keeping warm 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 preparation 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 cyclodextrin compound crosslinking agent: 144.3 parts of hydroxyethyl-β-cyclodextrin were heated and dissolved in a 1% sodium hydroxide aqueous solution, and then 40 parts of an allyl epoxy-terminated polyether with a molecular weight of 200 were added, and 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 crosslinking agent.

[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 crosslinking agent and 4 parts of emulsifier AEO were added to 120 parts of deionized water and stirred for emulsification to obtain a 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; 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 by keeping warm 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 preparation 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 into 120 parts of deionized water, stir and emulsify, and obtain core layer monomer emulsion.

[0042] (2) Preparation of cyclodextrin compound crosslinking agent: 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, and 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 crosslinking agent.

[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 crosslinking agent and 5 parts of emulsifier AEO were added to 120 parts of deionized water and stirred for emulsification to obtain a 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; 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 by keeping warm 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, the shell monomer emulsion does not add an allyl polyether modified cyclodextrin compound cross-linking agent, comprising 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 for emulsification 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 ink resin emulsion, compared with Example 1, uses an equal amount of pentaerythritol triacrylate cross-linking agent to replace the allyl polyether modified cyclodextrin compound cross-linking agent, and the rest is the same.

[0052] The application performance of the ink resin emulsion obtained in the above examples and comparative examples in the preparation of water-based ink was tested. 1 part of the ink resin emulsion was added to 1 part of the water-based color paste and dispersed evenly, and then applied to the surface of the PE film and dried and solidified. The adhesion fastness was tested according to GB / T13217.7-2023. The water resistance test was conducted by soaking in 48°C warm water for 48 hours and drying at 80°C to test the adhesion fastness. The tinting strength test was based on GB / T13217.6-2008. The test results are shown in Table 1 below.

[0053] Table 1

[0054] Test sample Adhesion fastness Water resistance Tinting Strength 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] It can be seen from the comparison results of Examples 1 to 3 and Comparative Example 1 in Table 1 that the shell emulsion of the present invention is cross-linked and modified with a specific cyclodextrin compound cross-linking agent, which can significantly improve the adhesion, water resistance and tinting power of the resulting water-based ink coating. It can be seen from the comparison results of Example 1 with Comparative Examples 1 and 2 that the use of conventional pentaerythritol triacrylate cross-linking agent has an adverse effect on the tinting power of the resulting water-based ink coating, and the effect of improving adhesion is not significant. The reason is that the high content of pentaerythritol triacrylate cross-linking agent leads to an excessively large cross-linking density of the product, and the excessive embedding of polar groups leads to the poor binding and dispersibility of the resin emulsion to the color paste, and the binding force with the substrate film is reduced.

[0056] The above embodiments are preferred implementation modes of the present invention, but the implementation modes 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 equivalent replacement methods and are included in the protection scope 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: adding styrene, (meth)acrylate monomer and emulsifier into deionized water and stirring and emulsifying to obtain core layer monomer emulsion; (2) Preparation of a cyclodextrin compound crosslinking agent: heating a cyclodextrin compound to dissolve it in an alkaline aqueous solution, then adding an allyl epoxy-terminated polyether, and reacting at 60 to 90° C. to obtain an allyl polyether-modified cyclodextrin compound crosslinking agent; (3) Preparation of shell monomer emulsion: adding (meth)acrylate monomer, (meth)acrylic acid monomer, allyl polyether modified cyclodextrin compound crosslinking agent and emulsifier into deionized water, 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; and then the shell layer monomer emulsion and the initiator solution are 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, characterized in that: 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, characterized in that: The mass percentages of styrene and (meth)acrylate monomers in step (1) are: styrene 15% to 30% and (meth)acrylate monomers 70% to 85%.

4. The method for preparing a high-adhesion ink resin emulsion according to claim 1, characterized in that: The emulsifier in steps (1) and (3) is at least one selected from sodium dodecyl 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, characterized in that: 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 to 800; the molar ratio of the allyl epoxy-terminated polyether to the cyclodextrin compound is 2 to 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.