The introduction of fillers for coatings and their application in coatings.

filler pigments (fillers) may be named as reminiscent of the fact that they do not have a large weight and are of value only for superficial research purposes. In practice, however, fillers have a significant impact on the performance of most coloring coatings. Because of the variety of filler types and the wide variety of performance, most coating formulaters have not yet thoroughly figured out their performance and the best application. This situation raises the possibility of using special fillers to improve the quality of coating products.White fill pigment is a mineral material with a fairly low refrengation index, which differs from each other in composition, particle size and granular shape, showing very low masking performance in light and semi-gloss coatings, but giving the coating a "high dry cover" effect (between air/pigment interfaces) on a low-cost basis in flat paint. Therefore, fillers can be used to adjust the gloss, texture, suspension, viscosity of the coating, etc. , the main types of fillers are carbonates, silicates, sulfates and oxides.particle size range of practical fillers is 0.01 to 44 m, in spherical, needle-shaped, fibrous and flaky forms. Filler particle morphology affects its packaging, film flexibility and cracking. Particle size and particle size distribution affect cover force, viscosity, coating porosity, media and surfactant requirements, gloss and fineness, etc. The reactivity between the filler and the coating substate is important and will affect the salt mist, foaming, rusting and cracking properties of the coating film.has done a lot of work in replacing one filler with another to produce comparable coating properties, and has found that when fillers replace each other with equal weight or volume, different coating properties such as consistency, durability, permeability, scrub resistance, contamination resistance, photoresisting, etc. are produced.fillers are made by grinding natural ores, or by chemical precipitation and then processing refining and granular grading, and the separation process includes wet or dry screening, flotation and centrifugal separation. Raw materials and processing processes may affect their pigment performance.Calcium carbonate or white soil: CaCO3
Is one of the most commonly used fillers in both internal and external coatings to control the gloss, mold, consistency and cost reduction of coatings. Calcium carbonate has two types of natural and synthetic (precipitation production), the particle size range is very wide, 0.05 to 44 m can be applied. Natural calcium carbonate is used in large quantities, as it is cheap, in some uses is quite appropriate. Varieties with a coarser particle size are limited to putty, seam pulp, metal primers and other high pigments that require flow and rough surfaces. Coarse-grained calcium carbonate has very low light-absorbing capacity. Medium particle size varieties are mainly used for internal flat and semi-gloss coatings as well as for housing coatings. Most of the fine particle size varieties are produced by precipitation and are used for printing inks. Calcium carbonate of both particle sizes is usually used together to achieve performance balance.
natural calcium carbonate fillers are made from limestone, marble and British calcium carbonate. Most varieties have CaCO3 content of 95% to 99%. Some varieties are dried and then flotation prepared. Finer is ground with wet, and then graded by precipitation or centrifugation. Granulation, average particle size, particle size distribution and purity vary widely among many brands.
natural calcium carbonate fillers are also widely used in outdoor housing coatings, can be used alone, can also be used with talcum powder. Compared with talcum powder, natural calcium carbonate can reduce the powder rate, improve color preservation and improve anti-pollution performance. The above uses put forward specific requirements for particle size. Fine particle size varieties, especially those called "fine" grades, can cause crack tendencies in the coating. Tests have proved that this type of calcium carbonate filler particle size should be larger, medium demand is low, activity should also be low. These fillers are also suitable for outdoor housing with latex paint to improve color preservation performance. Calcium carbonate is an alkaline substance that acts as a buffer in water-based coatings, but cannot be used with alkali-sensitive color pigments, such as iron blue and chromium green; Calcium carbonate cannot be used in acidic catalytic melamine polyester paint because it neutralizes the reaction with the catalyst. As a type, caCO3 content of precipitation or synthetic calcium carbonate fillers is 98% to 99%, with small particle size, narrow particle size distribution, high oil absorption and higher brightness than natural products. One of the better brands of particle size range of 0.03 to 8 m, is belonging to the collate range. It has been reported that the optimum particle size is about 0.2 m for internal latex paint and paper coating cover. Precipitated calcium carbonate is best suited for applications where maximum dry cover is required. Some varieties have been surfaced with pine or fatty acids, further improving their wetting and dispersion properties, and are used in light coatings without significant loss of light. In some formulations, the permeability of surface pores can be reduced, thus increasing the closing effect of the head coating.Magnesium silicate or talcum powder: 2MgO-4SiO2-H2O
This is a class of minerals with abundant reserves, mined around the world, with crystalline and related physical characteristics varying from origin to origin, usually a mixture of various crystal types. The effect of industrial talc powder on coating performance is controlled by its structure type or mixture type, average particle size and particle size distribution. Because most talc powder products are basically fibrous or flaky, their classification is also based on this. Fibrous talcum powder outdoor durability is the best, but in the paint is less mobile, coating film flatness is not enough. Flaky talc powder gives the coating excellent brushability, leveling, coating flatness and photoresistability, but also gives the coating or ink a "lubrication" performance. The small amount of granular talc powder, but with the best adhesion and wearability, indicates that it is suitable for polishable closed paint or surface coatings.
Many brands of talcum powder are designed and produced for special purposes or purposes, with particle sizes varying from large particle sizes that are fairly coarse and have very low oil absorption to "ultra-fine" levels with high oil absorption, with Hegman fineness values as high as 7. There are also surface-treated, low oil absorption, Hegman fine value of only 6 to 7 talcum powder varieties, such varieties are suitable for photomagnetic grade. The performance of talc powder also varies according to the requirements. The dry powder brightness of talc powder is high, and the color is good in both water and oily systems. Talcum powder is easy to moisten and disperse in all liquid coatings, such as organic solvents, varnishes, alkalic acids and water-based systems; Talc powder has excellent suspension in coatings and can also help other pigments in the system to remain suspended.
powder with a coarser particle size is suitable for some coatings that require rough coating or "toothed", such as interior paint, primer, and tinted paint. The medium particle size variety (Hegman fineness value is about 4) is suitable for house paint and can also be used as a general filler. Ultra-fine-grade talc powders with Hegman fineness values of 5 to 7 are suitable for controlling the gloss, consistency and flow-on properties of semi-gloss coatings. Talcum powder is used in large quantities in glue, crack fillers and putty. Special products according to the requirements of different decisions to choose coarse particle size or fine particle size talc powder.
can be used in a variety of industrial coatings, especially primers. Steel structure with primer can be all or part of talcum powder, can improve the precipitation of the coating, coating mechanical force and re-coating. Talcum powder is preferred for many products and flash primers and transport vehicles. Tablet magnesium silicate, including talc, is suitable for metal primers because of its improved polishing and water resistance, where water resistance may be derived from flaky particles extending the way moisture passes through the coating.aluminium silicate or porcelain soil, kaolin: Al2O3,2SiO2,2H2O
porcelain soil (kaolin) fillers are composed of aluminum silicate, produced in the United States Carolina, Georgia and England and other places. Initially, porcelain soil was consumed as a cheap filler in the paper industry and is still widely used. In recent years, manufacturers are making porcelain soil suitable for the development of the coating industry. Originally produced simply by air drying and flotation, it has now been replaced by washing, strict granularity control, calcination and surface treatment, thus improving the grade of the product. In these reforms, calcination is the most important process, so it is very large. The majority of porcelain particles are thin flakes, or hexagonal flakes. The most versatile variety has a particle size of approximately 10 m. All varieties of porcelain soil have varying degrees of hydromassiveness, chemically neutral, non-calcined varieties of oil absorption of 25 to 44, calcined varieties of 48 to 58. The brightness is 80% to 92% reflective. Porcelain fillers weigh about 21.6 pounds per gallon, about 1 pound less than calcium carbonate. Because its flaky body can enhance the mechanical force of the coating, so porcelain soil can give the coating film softness. If used in house coatings, powder resistance is stronger than talc powder. Porcelain soil has been widely used in metal primers to improve its polishing performance. Calcined porcelain soil is increasingly used in indoor flat-light wall paint and coatings that require a flat coating. The particle size of these varieties is extremely fine and is used in colored half-light and light-available coatings to reduce floating color and floating tendencies. In solvent-based coatings, some varieties of porcelain soil tend to sink, but after calcination and surface treatment of varieties can overcome the above disadvantages. Due to porcelain soil hydro-water, so it is a good filler for water-based coatings, they have good suspension properties in water-based coatings, easy to disperse, and give the coating a good brush coating and leveling. Porcelain soil is usually used with other fillers.sulfate: CaSO4 and CaSO4-2H2O
Filled pigments exist in two basic forms: waterless gypsum and gypsum (or gypsum powder). Only the first form is widely used in the coatings industry. Waterless gypsum can be made by calcining gypsum. The waterless gypsum is bright and well dispersed in coatings and can be used in some light coatings as well as other types of products that require their special properties.
waterless calcium sulfate is slightly soluble in water and forms a gypsum, so slender crystals are formed when stored in latex paint. However, it is this water solubility that allows it to react with certain parts of latex paint, so the application of waterless gypsum powder is very limited.heavy crystals or sulphate: BaSO4
Practical nicotic acid-filled pigments come in two forms: after grinding heavy crystal powder and precipitated palladium sulfate. Recent progress in the production of heavy crystalline powder through grinding and rinsing processes has been to improve the color and fineness, and the precipitation method of sulphate with excellent chroma and finer particle sizes has not been widely used in the coatings industry because the former meets the requirements and is less costly. The main uses of vanadium sulfate are industrial primers, including automotive primers. Because of its low oil absorption, high density, granular or spherical structure, it has good filling properties, helps with luster and has good light preservation. Radon sulfate is almost always used in these coatings, which are important for the luster of the head paint. Chemical properties make it valuable in a chemically resistant coating that is applied under high acidic conditions.Silica dioxide: SiO2
There are three different types of practical silica: (
1) ordinary silica made from grinding and grading quartz; This type of filler is difficult to disperse and easy to sink the lumps. Because it is not wear-resistant, it can change color severely when grinding in roller or ball grinding. It is the main filler used in wood filler, for this reason, it has a good comprehensive performance, low oil absorption leads to low shrinkage, with the substation does not react, coating film roughness is good.
(2) diatom soil or a fixed-shaped silica: this type of silica is widely used due to good lighting. The content of silica is about 83% to 95%. Most products are white and a few are light gray, light powder or beige. Low surface density, high oil absorption, coupled with irregular structure, these combined factors make it produce a high light-absorbing effect, thickening capacity and good suspension performance. Diatom soil is widely used in internal flat-light wall coatings. Due to the large pores and brittle texture, it has a negative effect on the de-fouling and scrubbing resistance of flat-gloss wall coatings, but is brighter than most other fillers after friction and washing. This type of silicon dioxide has also been used in outdoor housing coatings to dissipate light, and has been reported to contribute to comprehensive durability, depending on consistency, brush coating and fluidity results. It is advantageous to use only high-speed stirring or pebble grinding for short dispersion in paint, otherwise the brittle particles of this silicon dioxide may be destroyed, greatly reducing their light-down capacity and suspension in the coating. Since it is not realistic to significantly reduce the particle size of silica in coating production, it is important to carefully select the brand of diatom soil and measure the fineness with a Hegman meter.
(3) Synthetic silica: This is also an ana fixed-shaped silicon dioxide, produced by synthetic method, with strong light-down capacity, suitable for nitro spray paint, varnish and magnetic paint to reduce gloss. Mica: K2O-3Al2O3-6SiO2-2H2O
Mica contains several minerals with different compositions and properties, and the above-style white cloud mica is a common raw material for mica powder fillers. Mica exist in the form of multi-layered crystalline sheets like books. When the ore is stripped into pieces under the action of compressed air, it is then moistened and dried to make a mica filler. Wet-grinding varieties are the most versatile and have a fairly large particle size of about 325 eyes (43 m). There are also varieties with particle sizes of only 5 to 10 m. Mica has a unique flaky structure, which is the root cause of its special properties, including enhancing the mechanical force of the coating, increasing the length of the path that water or moisture must pass through the coating film. Adding a small amount of mica powder to oily house paint prevents cracks, and also has crack resistance and improved scrubing in wall latex paint. The proportion of mica powder used in coatings is generally very low, only 5% of the total amount of pigment. A small amount of mica can be used as a special part of some U.S. federal specification structural steel primers to improve salt spray resistance and durability. In outdoor coatings, mica give the coating a bright light by reflecting light, which is important for some products. Calcium silicate: CaSiO3
Calcium silicate made from silica ash has a needle-like structure, good brightness and low oil absorption, suitable for oily house coatings, flat or semi-light interior coatings and latex coatings. Its pH is about 9.9, which acts as a buffer in latex paint under alkaline conditions.
synthetic calcium silicate is a type of hydrated calcium silicate, produced by hydrothermal reaction of diatom soil and lime. The granules can vary from "garden-shaped" to needle-shaped. The average particle size of all varieties is 1.6 to 3.8 m, which is in the colleome range. Its better variety is white. This type of filler has superior properties over diatom soil, and its high oil absorption means strong de-lighting capacity and high dry covering effect. Apply proportions to coatings.