Summary of packing is commonly used in coatings2016.03.11 09:15
Coating is a kind of present flow state or can be liquefied solid powder or thick pulp state, can firmly adhere to the uniform coating and the coated surfaces, and the coated objects have adornment effect, protection and special effect, or several role both film forming material.
Coating product besides paint, also includes the use of a variety of synthetic resin, emulsion, etc as main raw material to produce solvent type paint, latex paint, water soluble coatings, powder coatings, etc.
Coating of inorganic fillers, also known as extender pigment, sometimes called extender pigment, can be divided into the functional filler and functional filler. The former mainly incremental effect, to reduce the cost of raw materials of coating. The latter besides have incremental effect, but also has improvement of performances of the coating or coating of some functions, such as control rheology, improve adhesion, gloss, improving covering power, to prevent corrosion and optimization of pigment volume concentration, etc.
Coating is one of the main users of the inorganic filler, the coating production of about 23 million tons per year in the world today, a total of about 6 million tons/year consumer packing. Our country has become one of the paint production country in the world, about 3 million tons/year production of coatings, consumption of inorganic filler about 800000~1 million tons/year.
The features and requirements of fillers in coatings
The packing (inert pigment), coating is usually white or slightly with the color of the refractive index of less than 1.7 type of paint. It has the basic physical and chemical properties of the coating pigment, but as a result of the refractive index similar to film-forming material, thus is transparent in the paint, do not have coloring pigment tinting strength and hiding capacity, is indispensable to a kind of pigment in the coating. Because most packing are from natural ore processing products, its chemical stability, good wear resistance, water resistance and other properties, and the price is low, backbone role in the coating. Increase the thickness of the coating by filling, mechanical performance is greatly improved, and durable, corrosion resistance, thermal insulation, extinction, etc. On the other hand it as a way of reducing coating manufacturing costs, with its low price, the price is much lower than the color pigments, on the premise of meet the film covering power, extender pigment was added to supplement the appropriate color pigments in the paint volume.
Coating used in packing, reduce the cost is not the only role. Packing is: the main role and function in coating frame, the filling effect, increase the film thickness, film plump solid; Adjust the rheological properties of coatings, such as thickening, precipitation, etc.; Mechanical strength, improve film such as improve the abrasion resistance and durability; Adjust the optical performance of coatings, change the appearance of the coating, such as extinction; Film-forming material produces chemical reaction, make into a whole, make the coating can effectively block the light penetration, improve the water resistance and weather resistance, extend the service life of coating; As filler in the paint, reduce the dosage of resin, reduce the production cost; The chemical properties of the coating, a supplementary role such as rust, moisture resistant, flame retardant, etc; Different coating grade and technical requirements of the packing is different, but the coating with the general requirements of the packing as follows; White degree should be high, especially in the coating color coating, high whiteness general requirements above 90%; Easy dispersed, it is not only beneficial to reduce coating production grinding scattered energy and time, more important is conducive to the coating performance of the play, because of filler and pigment dispersion is good or bad, on the coating performance (luster, color, durability, etc.) has a direct influence; Should have lower oil absorption, oil absorption value low to improve coating the critical pigment volume concentration (CPVC), save resin binders, and can adapt to meet the requirements of environmental protection requirements of modern high solid coatings, content is higher is prepared beforehand scattered packing pulp, talents and increasingly reduced oil absorption value of pigment (especially titanium dioxide) matching. Should be to determine the particle size and narrow particle size distribution, sieve residue should be as low as possible, coating requirements packing in many application fields have now ultra-micronization model.the ultrafine particle size, even in this way can we give play to the role of it in the space in the coating, the coating of the pigment particles were distributed evenly, so as to maximize cover, such as titanium dioxide pigment, coloring, such as color pigments and rust (such as antirust pigment) potential, have the effect of partly replace pigments; Can make the coating has good rheology (liquidity, flow resistance, suspended, thickening, etc.), make the paint without precipitation during storage, facilitating construction film, coating formed smooth level off; Should be with the basic material in the coating, paint and other additives have good compatibility but also should have certain inertia, does not react with the component; With appropriate specific surface area, because it affects the paint viscosity, rheological property, dispersion stability, sedimentation and oil absorption, etc.; Has a certain particle shape and crystal form, make the paint has to determine the refractive index of optical properties and the packing function as it should be in the coating.