Coating classification: matting agent for water-based Wood Matt varnish

Core tip: Introduction: With the increasing requirements of environmental protection and health, water-based coatings, especially water-based wood coatings, have been widely used in the market because of their advantages of low pollution and non combustible construction According to its luster, water-based wood coatings can be divided into matte, semi gloss and bright In practical application, waterborne emulsion has many difficulties in Matt varnish, especially the dispersion of traditional matting powder, storage stability of coatings, transparency of coating film and rheological properties of coatings In the process and formulation, a lot of adjustment is needed to make satisfactory matching species Shenyang steel structure fireproof coating construction expert punde Building Fire Engineering Co., Ltd Recommended introduction: since its establishment, Shenyang punde Construction Fire Engineering Co., Ltd has cultivated a group of professional construction teams with excellent equipment, rich experience and serious responsibility with advanced and scientific management methods and strict engineering quality assurance and after-sales service system It has undertaken a number of fire system installation projects, which has been praised by customers Every idea and special requirement of you will be fully considered by us and fully realized in the construction technology, which will become the cornerstone of our successful long-term development We are looking forward to your invitation, to provide you with quality services and high-quality technical support! All construction coatings have passed ISO9001 Introduction: with people's increasing requirements for environmental protection and health, water-based coatings, especially water-based wood coatings, are favored by people and widely used in the market due to their advantages of low pollution and convenient non combustible construction According to its luster, water-based wood coatings can be divided into matte, semi gloss and bright In practical application, waterborne emulsion has many difficulties in Matt varnish, especially the dispersion of traditional matting powder, storage stability of coatings, transparency of coating film and rheological properties of coatings In the process and formulation, a lot of adjustment is needed to make satisfactory matching Types: there are three kinds of common matting agents: metal soap, wax and functional body filler The metal soap is a kind of matting agent commonly used in solvent coatings in the early days It disperses in the coating with very fine particle suspension When the film is formed, it is distributed on the surface of the film to produce micro roughness and reduce the reflection of the surface light of the film It mainly includes aluminum stearate, zinc, calcium, etc Because the polarity difference between them and water-based resin is too large, it is difficult to disperse them in water, so they can not be used in water-based wood coatings Wax is also an earlier matting agent After coating construction, wax gradually precipitates out in the drying process of the paint film, forming fine crystals, floating on the surface of the paint film, and forming a rough surface, so as to play a role in extinction, but the wax layer on the surface of the paint film will also prevent the evaporation of solvents, affecting the drying of the paint film There are mainly low-molecular-weight polyethylene, polypropylene and so on They can not only dull, but also give the film good scratch resistance and good feel In solvent based coatings, wax and silica matting agent are usually used together The matting wax used in solvent based coatings can not be dispersed in water-based resins and can not be used directly Therefore, some businesses have made it into water-based emulsion wax so that it can be used in water-based systems However, there are few matting water-based emulsion waxes that can be truly commercialized for water-based systems, and there are problems of compatibility with water-based resins If the compatibility is not good, it will cause water-based emulsion wax or water-based resins to occur in the system Demulsification or gel Ø functional physical filler functional physical filler belongs to inorganic filling type matting agent When the paint film is dry, due to the light density, it will float on the surface of the paint film, making the surface of the paint film slightly rough, thus playing a matting role The functional fillers mainly include diatomite, synthetic silica, etc Among them, the synthetic fumed silica has high extinction, its refractive index is about 1.46, which is the most similar to the refractive index of resin (1.4-1.6), and has little influence on the transparency of paint film It is not easy to whiten when it is coated on the surface of wood, especially dark wood, so it is widely used in solvent based matte wood coating Extinction mechanism: luster is the reflection characteristic of the object surface to the light When the incident light hits the paint film surface, it will reflect and scatter If the surface of the paint film is flat, the larger the reflective part is, the higher the glossiness is Otherwise, if the surface of the paint film is uneven and very rough, the scattering part will increase, and the glossiness will be low, that is to say, the effect of extinction will be produced The addition of the matting agent makes the surface of the paint film rough and uneven, which causes the random reflection of light to weaken the reflected light intensity, so as to achieve the goal of matting Obviously, if the matting agent is added, the rougher the surface of the paint film, the better the matting effect Preparation process: O basic formulation, waterborne wood coatings based on matting emulsion and basic formulation of waterborne wood coatings based on matting powder are as follows: O preparation process of waterborne wood coatings based on matting emulsion: add waterborne latex into containers in a row, stir evenly and add defoamer 1 Stir for 5 min at 600 R / min; mix film-forming aid 1, film-forming aid 2, rheological aid, wetting leveling agent, thickener and H2O evenly, then slowly add them into the fast mixing container, stir for 10 min at 1200 R / min; add defoamer 2 and preservative, stir for 5 min, and then filter out The preparation process of waterborne wood coatings based on matting powder: adding waterborne emulsion, dispersant and defoamer 1 into containers, stirring evenly, adding dispersing powder, dispersing 1200 r/min rapidly to fineness of less than 30 m, and making film builder 1 , film forming aid 2, rheological aid, wetting leveling agent, thickener and H2O are mixed evenly, then they are slowly added into the fast mixing container, and stirred for 10 minutes at 1200 R / min; defoamer 2, preservative are added and stirred for 5 minutes, and then filtered out Use: the matting agent is easy to form aggregates in the process of transportation and storage Different from the general pigments and fillers, it does not need to use the equipment with strong shear force to disperse the matting agent If the sanding machine and three roller mill are used for grinding, the matting agent will be excessively dispersed, but the matting effect will be reduced There are two ways to add matting agent: direct adding method and prefabricated matting paste adding method The two methods have their own characteristics The process of direct addition method is simple For any system, the amount of matting agent can be determined according to the required gloss of the paint film, and the formulation parameters of the paint, such as solid grading, can be adjusted according to the needs In addition, the solid content of the paint prepared with low solid content resin (such as waterborne polyurethane, etc.) can be increased, and the thickness of a brush can be increased, thus increasing the fullness of the paint film However, due to the poor wettability of the water-based resin, it is difficult to disperse when the matting agent is directly added to the water-based resin than the solvent system, which requires longer dispersion time, which may cause the water-based resin with poor mechanical stability to produce agglomerates or even demulsification The addition method of pre prepared matting slurry only needs to disperse the matting slurry evenly in a short time, which improves the production efficiency, especially suitable for large-scale production However, the concentration of the matting agent in the matting pulp is generally lower than 20 %The effective concentration of the matting slurry prepared by the matting agent with high porosity is lower If the coating with low gloss is prepared, the solid content of the coating will be reduced seriously In addition, the matting slurry contains other components After being added to the coating, the final formulation of the coating will be affected Especially, the formulation of the coating with different gloss is quite different The formulation designer must take these changes into consideration and make the formulation according to the needs Adjust accordingly to ensure that the performance of the final coating is not affected 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,