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    Home > Coatings News > Paints and Coatings Market > Common knowledge of coatings: modification and application of Waterborne Polyurethane Coatings

    Common knowledge of coatings: modification and application of Waterborne Polyurethane Coatings

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
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    Core tip: the waterborne polyurethane coating combines the advantages of high hardness, strong adhesion, corrosion resistance and solvent resistance of polyurethane coating with the low VOC content of waterborne coating, which conforms to the "three prerequisites" (resources, energy, no pollution) and "four e principles" (economy, efficiency, ecology, energy) for the development of coating industry However, the general polyurethane emulsion has poor self consistency, low solid content and poor water resistance of latex film In order to better improve the comprehensive performance of waterborne polyurethane coatings and expand the application scope, it is necessary to use WPU Which is the price of Dajin diatom mud Recommended brief introduction: which is the price of Dajin diatom mud? How to buy genuine diatom mud? Guangdong diatom mud agent suggests placing a basin of cold water in the air conditioning room, so that the diatom mud wall can breathe effectively The feature of the breathing wall is obvious When the indoor air is dry, the diatom mud wall will release the absorbed water quickly Put it out to help regulate the indoor dry humidity It is suggested to place a basin of cold water in the air conditioning room, so that the wall of diatom mud can breathe effectively The feature of the wall that can breathe is obvious When the indoor air is relatively dry, the wall of diatom mud will absorb the water Home of coatings: waterborne polyurethane coating combines the advantages of high hardness, strong adhesion, corrosion resistance and solvent resistance of polyurethane coating with the low VOC content of waterborne coating, which conforms to the "three prerequisites" (resources, energy, pollution-free) and "four e principles" (economy, efficiency, ecology, energy) for the development of coating industry However, the general polyurethane emulsion has poor self consistency, low solid content and poor water resistance of latex film In order to better improve the comprehensive performance of waterborne polyurethane coating and expand its application range, WPU emulsion needs to be modified properly This paper mainly introduces the research of waterborne polyurethane coatings, such as epoxy resin modification, polysiloxane and acrylic acid composite modification, nano modification, etc., and points out that the modification of waterborne polyurethane coatings is imperative and is gradually becoming an important pillar in the coating industry 1、 The modification technology of waterborne polyurethane coating can obtain better performance than physical blending by introducing other chemical components into the polyurethane molecular chain, which is the current development direction of waterborne polyurethane The common modification methods are as follows: (1) epoxy resin modified epoxy resin has many excellent properties, such as many kinds, easy to cure, high mechanical strength, strong adhesion, low molding shrinkage, good chemical stability, good electrical insulation, high modulus, high strength and so on Through the grafting reaction of epoxy resin and polyurethane, the branching point can be introduced into the main chain of polyurethane so as to form part of the network structure, and the epoxy modified polyurethane emulsion can be prepared The waterborne epoxy modified polyurethane coating can be prepared with the epoxy resin modified polyurethane emulsion, and the mechanical property, heat resistance and adhesion force of the film can be improved Zheng Shuqin and other synthetic epoxy resin E-44 modified waterborne polyurethane emulsion has good appearance and stability, and its water resistance and heat resistance have been greatly improved (2) The two most remarkable characteristics of organosilicon modified organosilicon polymer are oxidation resistance and low surface energy The silicone modified polyurethane can synthesize the excellent properties of the two, and make up for the defects of the poor hydrolysis resistance of the water-borne polyurethane, so that the modified waterborne polyurethane coating shows good hydrophobicity, surface enrichment, low-temperature flexibility and excellent biocompatibility Li mizhuan et al Synthesized organosilicon waterborne polyurethane by introducing organosilicon monomer into the end capped waterborne polyurethane Its water absorption property is about 17.1%, and its water resistance is greatly improved (three) polyacrylate modified polyurethane emulsion and polyacrylic emulsion have the advantages of low cost, safety, non combustible, non-toxic and no pollution to the environment compared with their solvent products Pure PA emulsion has defects of wear resistance, water resistance and chemical resistance Single PU emulsion also has some shortcomings, such as stability, self thickening and optical retention of film, which is limited in application PUA composite emulsion has two advantages, such as wear resistance, corrosion resistance and brightness, flexibility, elasticity, water resistance, good mechanical properties and good weatherability Therefore, it is known as the "third generation waterborne polyurethane" and has become a trend of today's coatings (4) Silicone acrylate double modified waterborne polyurethane combines polyurethane acrylate organosiloxane to prepare waterborne coatings It integrates the advantages of acrylate, polyurethane and silicone resin materials, and water as the dispersion medium meets the requirements of environmental protection The three are organically combined, and can be made into soap or soap free emulsion according to different requirements and advantages of synergy They are used as coating agents and leather finishing agents for textiles Wang Haihong and other emulsion polymerization methods were used to prepare silicone modified acrylic polyurethane emulsion with core shell structure The results showed that the adhesion, stability, hardness and gloss of silicone modified acrylic polyurethane emulsion increased significantly (5) Nano materials modified by nano materials have special properties such as surface effect, small size effect, optical effect and quantum size effect, which can make the materials obtain new functions Adding a proper amount of Nano-SiO2 to the exterior wall coating can improve the weatherability of the emulsion paint to a new level, and also greatly improve the aging resistance The practical application shows that after adding a small amount of Nano-SiO2 into the interior and exterior wall coatings, the anti ultraviolet and anti-aging test performance of the coatings can be improved from 250h to 600H, and the anti scrubbing test performance can be increased by more than 10 times, and the drying time can be greatly reduced Moreover, the problems of poor suspension stability, poor thixotropy and poor finish of the raw materials are also well solved Hsu-ChiangKuan and [13] synthesized a kind of nano carbon tube / waterborne polyurethane nanocomposite The waterborne polyurethane emulsion was stable, the thermal stability of the film increased by 26, the tensile strength increased by 370%, and the tensile modulus increased by 170.6% (6) Vegetable oil modified waterborne polyurethane vegetable oil is a kind of renewable resource The preparation of waterborne polyurethane with vegetable oil can further reflect the environmental protection awareness Zhou Yingping and other water-borne polyurethane resin coatings synthesized with vegetable oil at room temperature not only have good weather resistance, but also have the advantages of no pollution of waterborne coatings, which is an environment-friendly coating, It can be used not only as water-based interior and exterior wall coating, but also as wood decoration coating and fabric printing and dyeing coating Qiu Wei and other dry gas vegetable oils were used as raw materials to modify them and then implanted them into semi sealed PU chains The self emulsifying single component water PU was prepared The emulsion had good stability and excellent mechanical properties 2、 Application of waterborne polyurethane the original waterborne polyurethane is mainly used in fiber and leather treatment agents With the continuous improvement of performance, the application scope is more and more extensive, including coating, adhesive, treatment agent, emulsion polymer polymer emulsion and so on (1) coating agent (1) leather coating polyurethane material is flexible and wearable, and can be used as coating agent for natural leather and artificial leather instead of acrylate resin emulsion leather finishing agent The finished leather feels soft and full It can be used in shoes, clothes, women's bags, etc (2) Fabric coating is a new technology developed in textile finishing, which has high benefit and is one of the development directions of textile industry at home and abroad PU coating is the best one among all kinds of coating agents It has excellent film-forming and elasticity It is gradually replacing the solvent type PU coating agent with pollution and danger (3) As anionic electrophoretic paint, waterborne PU for automotive paint is a new technology, which has excellent performance and is the focus of development in various countries Water based Pu can also be used as the middle layer of automobile coating, with excellent performance Its adhesion, stone impact resistance, salt spray resistance and other properties can meet the application requirements (2) Adhesive water-based Pu can be used as adhesive for fabrics, non-woven fabrics, etc it is more suitable for the adhesion of porous surface materials and materials prone to solvent swelling, and generally has good adhesion performance This kind of adhesive generally requires two-component water-based Pu, which has better adhesive strength, water resistance and aging resistance than single component Water-based Pu can also be used as composite film adhesive with good performance 3、 Conclusion in order to improve the comprehensive performance of waterborne polyurethane coatings and expand the scope of application, in recent years, the modification of waterborne polyurethane has become a hot spot, many researchers have carried out in-depth and comprehensive research on the modification methods are also changing with each passing day With the continuous improvement of environmental protection, human health and coating quality requirements, the development of high-grade waterborne polyurethane coating is imperative With its excellent performance, the developing waterborne polyurethane coating is gradually replacing the traditional solvent based coating, which has been widely used in the fields of architecture, decoration and so on Waterborne polyurethane coating is gradually becoming an important pillar in the coating industry Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,
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