One-component transparent waterborne polyurethane emulsion waterproof paint and preparation method thereof

Abstract

The invention discloses one-component transparent waterborne polyurethane emulsion waterproof paint and a preparation method thereof and relates to polyurethane waterproof paint. The waterproof paint comprises a resin phase and a nano-material phase. The preparation method comprises the following steps: diol and a hydrophilic chain extender are dried, and other prepolymerization monomers are dried; diol, diisocyanate, fluorine-containing acrylate monomers and hydroxyl-terminated siloxane after a dehydration process are added to a four-neck flask, the mixture is heated and added with an organic tin initiator for a reaction under the protection of nitrogen, and the mixture is heated and added with dimethylolpropionic acid for continuous reaction; after a reaction system is cooled, the chain extender and acrylate monomers are added for a reaction; after a prepolymer is cooled to the temperature lower than the room temperature, a neutralizer and a cross-linking agent are added; then deionized water is added for emulsification, and mixed liquor A is obtained; a silane coupling agent is dissolved in absolute ethyl alcohol, silica microspheres are added to absolute ethyl alcohol, and mixed liquor B is obtained; the mixed liquor B is added to the mixed liquor A, the mixture is heated, and a radical initiator is added for a reaction; an organic solvent is removed, and the one-component transparent waterborne polyurethane emulsion waterproof paint is obtained.

Description

technical field [0001] The invention relates to a polyurethane waterproof coating, in particular to a one-component transparent water-based polyurethane emulsion waterproof coating and a preparation method thereof. Background technique [0002] With the rapid development of the national economy, the demand for coatings is increasing year by year. At the same time, people pay more and more attention to environmental protection, and the use of solvent-based coatings with a high content of volatile organic compounds is increasingly restricted. Waterborne polyurethane (WPU) is a green and environmentally friendly coating with polyurethane as the base material and water as the dispersion medium. Compared with traditional solvent-based polyurethanes, WPU not only retains the advantages of traditional solvent-based polyurethanes, but also has excellent properties such as non-toxic, non-flammable, and environmentally friendly. It has been widely used in coatings, adhesives, leather...

AI Technical Summary

Problems solved by technology

CN104293160A has prepared a kind of environment-friendly polyurethane coating, utilizes 2,4-xylene diisocyanate and polytetramethyl glycol to react to prepare aqueous polyurethane liquid, then adds nano-titanium dioxide, nano-silica and defoaming to this system The final environmentally friendly coating is prepared by stirring and mixing additives and film-forming aids. Although polyurethane can improve the anti-pollution and self-cleaning properties by adding inorganic nanoparticles, the dispersion of the particles is poor during the simple physical mixing process, and the coating Poor performance uniformity

CN103614065A Add water-based polyurethane emulsion, multi-functional additives, matting powder and deionized water sequentially under mechanical stirring, and then add surface additives, water-based wax emulsion, preservative and water-based thickener until the paint liquid is evenly prepared after dispersing for a certain period of time A kind of matte clear finish paint, although the product made in the present invention has higher hardness, and drying speed is also faster, but hydrophobic property is relatively poor

[0005] In recent years, due to polyurethane and its unique excellent properties, many people continue to explore and research. In 2013, Shin et al. reported a fluorine-containing waterborne polyurethane-acrylate block copolymer prepared by a solvent-free method (ShinMS , LeeYH, RahmanMM, etal.Synthesis and properties of waterbornefluorinatedpolyurethane-acrylateusingasolvent- / emulsifier-freemethod[J].Polymer,2013,54(18):4873-4882.), but this product is only pure resin polymerization, and the fluorine-containing segment acts as The soft segment exists in polyurethane, and the hardness of the coating film is low, which also makes the mechanical properties of the coating film relatively poor, and the water resistance and solvent resistance are poor.

In 2014, Luo et al. obtained water-based polyurethane through prepolymerization of diisocyanate and diol, emulsification of hydroxypropionic acid, chain extension of trimethylolpropane and 1,4-butanediol, and finally neutralization and dispersion. Emulsion (LuoQ, ShenY, LiP, et al. Synthesis and characterization of crosslinking waterbornefluorinated polyurethane‐acrylate with core‐shell structure [J]. Journal of Applied Polymer Science, 2014, 131 (21).), the organofluorine-modified waterborne polyurethane prepared in this article introduced trifunctional chain extension Compared with Shin's products, it has more network structure, which makes the cross-linking degree of the entire polyurethane molecule increase, and the hardness also improves to a certain extent, but the water resistance and solvent resistance still need to be improved.

Wu et al. reported a preparation method of transparent hydrophobic polyurethane modified by polydimethylsiloxane (WuZ, WangH, TianX, et al. The effects of polydimethylsiloxane on transparent and hydrophobic waterborne polyurethane coatings containing polydimethylsiloxane [J]. PhysicalChemistryChemicalPhysics, 2014, 16 (14-): 6787 6794.), the end-blocking agent in the article is 1,4-butanediol, and the hydrophobic performance of polyurethane is improved by adjusting the content of polysiloxane, but the drying time of the uncrosslinked coating film is long, and the viscosity of the film relatively high

In 2010, a method of adding inorganic nano-ZnO to polyurethane was reported to prepare water-based polyurethane (MishraAK, MishraRS, NarayanR, et al. Effect of nanoZnO on the phase mixing of polyurethane hybrid dispersions [J]. Progress in Organic Coatings, 2010, 67 (4): 405-413.), inorganic nano The material improves the temperature resistance of the polyurethane film, and although the contact angle with water has increased, the range is relatively small. The physical mixing modification of inorganic nanomaterials alone is not enough, and the uniformity of the physical mixing is poor. For improving the polymer film The mechanical properties are unfavorable

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