Organosilicon-modified aqueous polyurethane-acrylate composite coating agent and preparation method thereof

Abstract

The invention belongs to the technical field of chemical industry, and particularly relates to an organosilicon-modified aqueous polyurethane-acrylate composite coating agent and a preparation method thereof. The method comprises the following steps of: performing hydroxyl condensation reaction by using hydroxyl-terminated silicone oil and polyoxyethylene ether to prepare polyoxyethylene ether-containing hydroxyl silicone oil resin; introducing the polyoxyethylene ether-containing hydroxyl silicone oil resin into isocyanate-terminated polyurethane prepolymer by using a chemical bonding method; preparing organosilicon-modified aqueous polyurethane-acrylate dispersion through a self-emulsification method; and finally preparing the organosilicon-modified aqueous polyurethane-acrylate composite coating agent. According to the method, the problems of poor compatibility among the three components, i. e., organosilicon, polyurethane and acrylate and poor mechanical property of an aqueous composite coating layer of the organosilicon-modified aqueous polyurethane-acrylate composite coating agent are solved well. The preparation method provided by the invention has the advantages of simple process, convenience, high product quality, high input-output ratio and the like. The coating agent has high compatibility and superior mechanical property and is a new-generation environmentally-friendly high-performance chemical product.

Description

[0001] technical field [0002] The invention belongs to the technical field of chemical industry, and in particular relates to an organosilicon-modified waterborne polyurethane-acrylate composite coating agent and a preparation method thereof. Background technique [0003] Although silicone resin has excellent weather resistance and low surface energy, its coating has low mechanical strength and poor adhesion; polyacrylate resin has excellent light resistance, acid, alkali and salt corrosion resistance and excellent flexibility. However, its coating is extremely sensitive to temperature, has poor weather resistance, water resistance, and solvent resistance; polyurethane resin has excellent low temperature resistance, chemical solvent resistance, abrasion resistance, and strong adhesion, but its construction requirements are high. In order to overcome these shortcomings, a variety of polymer composite modifications are often used to improve its performance. Polyurethane / acry...

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Problems solved by technology

However, there are still many shortcomings in the above method. For example, due to the large difference in solubility parameters between silicone and polyacrylate and polyurethane, the silicone-modified acrylate-polyurethane system will undergo phase separation, so that the transparency of the coating will decrease. Cracking, adhesion, impact strength, bending resistance and other comprehensive mechanical properties are also affected, so it is necessary to adopt various methods to enhance the compatibility of silicone and polyurethane components to improve their mechanical properties

[0005] Chinese patent (application) CN1528800A discloses a silicone-modified acrylic polyurethane hybrid aqueous dispersion and its preparation method, obtaining a silicone-modified acrylic polyurethane hybrid aqueous dispersion with an interpenetrating network structure and a core-shell structure body, the silicone-modified acrylic polyurethane hybrid aqueous dispersion prepared by the invention has good heat resistance and solvent resistance, and also has good dispersion stability, the preparation process is simple, and the prepared silicone-modified acrylic polyurethane hybrid Water dispersions are widely used, and can be used as a base material component in one-component waterborne wood coatings and architectural coatings, and are stable in storage, but the process is complicated, and there is microphase separation in the obtained polyurethane-acrylate-organic silicon system. As a result, the mechanical properties of this type of material are not ideal, and it is difficult to apply industrially; Chinese patent (application) CN1664032A discloses a kind of acrylate emulsion as the main film-forming substance, adding water-based polyurethane emulsion, styrene-butadiene emulsion and silicone emulsion as modified The modified acrylic waterproof coating with additives avoids the shortcomings of a simple polymer emulsion waterproof coating such as poor waterproof effect and poor aging resistance. The advantages of cold construction, direct brushing and easy operation; Chinese patent (application) CN101153180A and CN101153181A disclose a kind of preparation method of modified acrylic roof waterproof coating, they use water-based polyurethane emulsion, ethylene-polyvinyl acetate emulsion and Silicone emulsion, etc. are modified by physical blending of modifier and pure acrylate emulsion, which has the advantages of high bonding strength, good waterproof and anti-seepage effect, heat resistance and frost resistance, good elongation performance, cold construction and direct painting, etc.; Chinese patent (application) CN101177553A discloses a composite UV-curable water-based paint and its preparation method, which is made by mixing epoxy-acrylate, polyurethane-acrylate, water-based photoinitiator and silicone defoamer; Chinese patent (application) CN101463222A discloses a UV-curable coating with urethane acrylate and silicone acrylate resin as the main resin. The UV-curable coating has good antifouling effect, scratch resistance, High gloss and adhesion; Chinese patent (application) CN101349028A discloses an improved fruit-growing bagging paper coating made from emulsified paraffin, polyurethane-acrylate emulsion and water-soluble silicone resin, so that the fruit-growing bag The bag has strong water resistance, air permeability and wet strength; Chinese patent (application) CN101280061A discloses a synthesis method of a silicone-polyurethane-acrylate ternary composite polymer emulsion. The method first uses hydroxyl-terminated polydimethyl Siloxane, N-methyldiethanolamine, toluene diisocyanate, polyisopropylene glycol, etc. have prepared water-based silicone-modified polyurethane, and then polymerized it with acrylic monomer to produce stable silicone-polyurethane-acrylate Emulsion, drying it to obtain a silicone-polyurethane-acrylate film; Chinese patent (application) CN101735599A discloses a UV-curable silicone-modified polyurethane-acrylate aqueous dispersion and a preparation method thereof. The method first Add polyester or polyether diol, hydroxyl-terminated silicone oil and trimethylolpropane dropwise to diisocyanate to react to obtain silicone-modified polyurethane prepolymer, and then add polymethylol propionic acid to In the above-mentioned organosilicon-modified polyurethane prepolymer, the organosilicon-modified polyurethane prepolymer after chain extension is obtained by reaction, and then the organosilicon-modified prepolymer after chain extension is treated with hydroxyethyl methacrylate or hydroxypropyl acrylate The body is subjected to end-capping reaction to obtain a silicone-modified polyurethane acrylate oligomer. Finally, a neutralizing agent such as triethylamine is added to neutralize the system, diluted with water, stirred, and emulsified to obtain a UV-curable silicone-modified polyurethane acrylic acid Ester water dispersion, the coating film after ultraviolet light curing has better water resistance and adhesion; but the invention patent disclosed above still has many deficiencies, such as its complicated process, high cost, and the obtained polyurethane-acrylate - There is microphase separation in the silicone system, which leads to the unsatisfactory mechanical properties of this type of composite coating agent, making it difficult for industrial application

[0006] At present, the waterborne polyurethane-acrylate composite coating agent modified by silicone at home and abroad is still not good in terms of mechanical properties, the compatibility of the composite system is not good, and it is environmentally friendly. The requirements are also high. In addition, with the development of new materials and new synthesis preparation technologies, a group of silicone-polyurethane-acrylate composite coating agents with good compatibility and mechanical properties have emerged, which is a new type of composite coating agent. The development of

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