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CN-121975464-A - Low-viscosity high-solid-content explosion-proof color water-based transfer adhesive and preparation method thereof

CN121975464ACN 121975464 ACN121975464 ACN 121975464ACN-121975464-A

Abstract

The invention discloses an explosion-proof color water-based transfer adhesive with low viscosity and high solid content and a preparation method thereof, and belongs to the technical field of water-based adhesives. The preparation method comprises the steps of firstly preparing polyurethane prepolymer by taking hydroxyl-terminated hydrogenated polybutadiene, 2-dimethylolpropionic acid, isocyanate and the like as raw materials, then adding hydroxyethyl methacrylate into the polyurethane prepolymer for grafting, using an acrylic acid monomer to replace an organic solvent such as acetone and the like to reduce the viscosity of a system before neutralization, emulsifying and chain extending after neutralization and salification to prepare WPU emulsion swelled with acrylate monomers, finally adding glycidyl methacrylate and SG1 initiator to controllably polymerize the acrylate monomers to prepare core-shell crosslinking WPUA composite emulsion, and then adding a crosslinking agent to crosslink epoxy groups in the glycidyl methacrylate. The water-based transfer adhesive disclosed by the invention has the advantages of uniform molecular weight, uniform molecular weight distribution and particle size, low viscosity, high solid content and excellent and stable explosion-proof performance.

Inventors

  • MAO YIDING
  • HE MINGHUI
  • XIE YI
  • LIN JIANXIONG

Assignees

  • 中丰田光电科技(珠海)有限公司

Dates

Publication Date
20260505
Application Date
20260205

Claims (10)

  1. 1. The preparation method of the explosion-proof color water-based transfer adhesive with low viscosity and high solid content is characterized by comprising the following steps: S1, mixing hydroxyl-terminated hydrogenated polybutadiene, 2-dimethylolpropionic acid, isocyanate and N, N-dimethylamide, heating, and after the 2, 2-dimethylolpropionic acid is completely dissolved, keeping the temperature and stirring until the two are fully mixed; S2, adding hydroxyethyl methacrylate for end-capping reaction after the-NCO content in the system reaches a theoretical value, cooling after the-NCO content in the system reaches the theoretical value, and adding an acrylic acid monomer for viscosity reduction; S3, adding triethylamine into the system prepared in the step S2, then preserving heat for neutralization reaction, continuously cooling the system after the reaction is finished, and then adding deionized water for high-speed stirring and emulsification; s4, adding glycidyl methacrylate and stirring after emulsification is completed, so as to obtain aqueous polyurethane/acrylic ester monomer dispersion; S5, refluxing the aqueous polyurethane/acrylic ester monomer dispersion liquid prepared in the step S4, stirring and heating, and dropwise adding an initiator SG1 for reaction to obtain a core-shell crosslinked aqueous polyurethane composite emulsion; And S6, when the anti-explosion water-based transfer adhesive is used, adding a cross-linking agent into the core-shell cross-linked water-based polyurethane composite emulsion prepared in the step S5 to obtain the anti-explosion water-based transfer adhesive.
  2. 2. The preparation method of the explosion-proof aqueous transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that the weight parts of each component in the step S1 are 50-70 parts of hydroxyl-terminated hydrogenated polybutadiene, 2-6 parts of 2, 2-dimethylolpropionic acid, 10-30 parts of isocyanate, 2-4 parts of N, N-dimethylamide and 0.01-1 part of catalyst.
  3. 3. The preparation method of the explosion-proof color water-based transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that in the step S1, the temperature is raised to 60-65 ℃ before heat preservation and stirring, the heat preservation and stirring treatment time is 0.5-1 h, the temperature is raised to 80-90 ℃ after adding a catalyst, the catalyst is stannous octoate or dibutyltin dilaurate, and the reaction time of the catalytic reaction is 2-3 h.
  4. 4. The preparation method of the explosion-proof aqueous transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that the weight part of hydroxyethyl methacrylate in the step S2 is 2-10 parts, and the acrylic monomer comprises 5-20 parts by weight of methyl methacrylate and 5-20 parts by weight of butyl acrylate.
  5. 5. The preparation method of the explosion-proof aqueous transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that in the step S2, after cooling to 70-75 ℃, hydroxyethyl methacrylate is added for end-capping reaction, the reaction time of the end-capping reaction is 1.5-2 h, and after cooling to 40-45 ℃, an acrylic acid monomer is added for viscosity reduction.
  6. 6. The preparation method of the explosion-proof aqueous transfer glue with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that in step S3, the weight portion of triethylamine is 2-6 portions, the weight portion of deionized water is 50-150 portions, the reaction time of the neutralization reaction is 0.5-1 h, the temperature is reduced to below 30 ℃ after the neutralization reaction is finished, and deionized water is added to stir and emulsify at the rotating speed of 10000-15000 r/min.
  7. 7. The preparation method of the explosion-proof aqueous transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that the amount of the glycidyl methacrylate in the step S4 is 2-10 parts by weight, and the stirring time is 0.5-1 h.
  8. 8. The preparation method of the explosion-proof color water-based transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that in step S5, the weight part of the initiator SG1 is 0.1-1 part, and the initiator SG1 is added to react for 4-5 hours after the temperature is raised to 80-90 ℃.
  9. 9. The preparation method of the explosion-proof aqueous transfer adhesive with low viscosity and high solid content, which is disclosed in claim 1, is characterized in that the cross-linking agent in the step S6 is at least one of diethylenetriamine, triethylenetetramine and isophorone diamine, and the weight part of the cross-linking agent is 1-5 parts.
  10. 10. A low-viscosity high-solid-content explosion-proof aqueous transfer adhesive is characterized by being prepared by the preparation method according to any one of claims 1-9.

Description

Low-viscosity high-solid-content explosion-proof color water-based transfer adhesive and preparation method thereof Technical Field The invention relates to the technical field of aqueous adhesives, in particular to an explosion-proof aqueous transfer adhesive with low viscosity and high solid content and a preparation method thereof. Background The anti-counterfeiting laser paper has been widely applied to fields of high-grade cosmetics, wine packaging, medicine packaging, propaganda products and the like due to the unique vision and anti-counterfeiting effect. The laser transfer paper does not contain a plastic film layer, belongs to a green environment-friendly material which is plastic-removed, light-weighted, degradable and recyclable, but the existing laser transfer paper generally has the problem of easy color bursting of paper, namely, obvious cracks formed by the ink of the laser transfer paper at an indentation line and an aluminum layer after printing, which not only can make the appearance of a printed matter rough and unattractive, but also can cause inaccurate information transmission and reduce the use value and commercial value of the product. The reason for influencing the burst color of laser transfer paper depends not only on the bending resistance of the paper itself, but also on the raw materials used in the preparation process. The transfer glue is an indispensable key part in the preparation of the laser transfer paper, plays a role in bonding the laser information layer and the paper, and plays an important role in the explosion-proof performance of the laser transfer paper. At present, common aqueous transfer glues can be classified into styrene-butadiene transfer glue, acrylic transfer glue and polyurethane transfer glue. Styrene-butadiene transfer adhesive has been widely used in laser transfer paper due to its good weather resistance, ageing resistance and low price, but the existence of styrene units makes the molecular chain of styrene-butadiene adhesive contain more rigid structures, limiting the rotation and bending of the molecular chain, so that when the styrene-butadiene transfer adhesive is subjected to external force, the molecular chain is difficult to buffer the external force through self deformation, thereby exhibiting poor flexibility. The acrylic acid transfer glue has the advantages of high curing speed, high transparency and the like, a compact three-dimensional network structure is formed through quick crosslinking reaction in the curing process, and the high crosslinking density improves the bonding strength, but also limits the ductility of molecular chains, so that the toughness of the glue layer is insufficient. The polyurethane transfer glue contains isocyanate groups and urethane groups, the proportion and the structure of soft segments and hard segments in a molecular chain can be controlled by adjusting the formula of polyurethane resin, so that the water-based polyurethane transfer glue with different hardness is prepared, the bending resistance of the material is enhanced to a certain extent, but the defects that 1, the viscosity of the polyurethane transfer glue is too high, the usage amount of water is too high, the solid content of the water is relatively low, and the solid content is mostly about 30%, and the overall cost is greatly improved still exist. 2. The polyol raw materials of the synthetic polyurethane transfer adhesive are mainly polyether polyol and polyester polyol, and the polyether type water-based polyurethane has good low-temperature performance and flexibility, good water resistance, but low mechanical strength, so that the explosion-proof color effect is not ideal, and the polyester type water-based polyurethane has high mechanical strength, good adhesive force and is not resistant to hydrolysis. In addition, the aqueous polyurethane prepared from hydroxyl-terminated hydrogenated polybutadiene (HTPB) and isocyanate (IPDI) has excellent mechanical properties, but the water resistance of a coating film is still to be improved due to the hydrophilic groups in the structure. Meanwhile, most of polyurethane transfer glue is linear molecules, and is formed into a film through solvent volatilization, so that the polyurethane transfer glue has poor heat resistance and does not contain a cross-linked network structure, and further the explosion-proof color effect is influenced. 3. The polyurethane glue has uneven molecular weight, molecular weight distribution, particle size and particle size distribution, and also has unsatisfactory explosion-proof color effect and unstable performance. In view of the foregoing, there is a need to develop an explosion-proof aqueous transfer gel with low viscosity, high solid content, low cost, excellent and stable color and a preparation method thereof. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide a preparation method of an explosion-proof aqueou