Application of talc and transparent powder in wood coatings

China Coatings Online News Information First, the composition and characteristics of talcum powder
The main component of talc is hydrated magnesium silicate, molecularly 3MgO.4SiO2. H2O, English name: Talc. Talc belongs to a single oblique crystal system. The crystals are false six-square or diamond-shaped flakes. Ore is usually formed into dense blocky, leafy, radioactive, fibrous complexes. Colorless transparent or white, but light green, light yellow, light brown, light red or even black due to a small amount of impurities; Soft, Mohs hardness 1-1.5, gravity 2.7 to 2.8. Talc micro-powder is made from sliding stone screening, cleaning, drying, ingredients, grinding, grading, packaging and other processes refined, for white powder, has a slippery feeling, with obvious lubricity, fire resistance, acid resistance, insulation, high melting point, chemical inertness, strong adsorption and other excellent physical and chemical characteristics. Talc powder according to the composition, origin, color of different, but also have different classifications, because of its natural many excellent quality, is widely used in paint, paint, plastic, paper, ceramics, cosmetics, pharmaceuticals, food, daily necessities and other industries.
II, talcum powder classification and use
1, chemical grade talcum powder
use: mainly used in rubber, plastics, paints, coatings and other chemical industries as modified fillers. Features: Increase the stability of product shape, increase adhesion, filling, covering force, sand light, increase the intensity of the shear, bending strength, pressure strength, reduce deformation, elongation rate, coefficient of thermal expansion, etc., high whiteness, uniform granularity, good dispersion and so on.
2, ceramic grade talcum powder
use: for the manufacture of high-frequency porcelain, radio porcelain, a variety of industrial ceramics, architectural ceramics, daily ceramics and ceramic glaze. Features: high temperature unchanged color, forging after whiteness enhancement, uniform density, good gloss, smooth surface.
3, cosmetic grade talc powder
: is the cosmetics industry's high-quality fillers. Features: Contains a large amount of silicon. It has the effect of blocking infrared light, thus enhancing the sun protection and anti-infrared performance of cosmetics. At the same time, talc powder slippery, pearly luster, on the skin has a certain protection and protective effect, easy to clean, non-toxic, harmless.
4, pharmaceutical, food-grade talcum powder
: for pharmaceutical, food industry additives. Features: Non-toxic, tasteless, high whiteness, good compatible, good gloss, soft taste, smoothness and so on. The PH value is 7-9, which does not change or degrade the materiality of the original product. Is the food, pharmaceutical industry high-quality stable filling additives.
5, paper grade talc powder
use: for a variety of high and low-grade paper industry products as filling. Features: Paper-grade talcum powder has the characteristics of high whiteness, stable granularity and low wear and tear. Paper made from talcum powder can achieve smooth surface, delicate, high gloss, good toughness, strong moisture absorption and so on, adding formula can save atomic material, improve the service life of the lipid mesh.
6, other uses talcum powder
talcum powder performance determines its use is quite extensive, in addition to the above-mentioned uses, but also can be applied such as wire and cable production isolation, mold release, daily life moisture absorption, lubrication, sports and casting lines. The main use of talcum powder slip, soft, dry and high temperature resistance and other characteristics.
, transparent powder overview
"transparent powder" is a common name in the paint industry, due to its excellent transparency, good appearance and better filling. In order to highlight its main characteristics for the first time and first impression, so take the common name "transparent powder". In fact, transparent powder is not a single powder, it in addition to the main ingredients of natural mineral rock, but also added a special synthetic accessories mixed grinding modified modulation. The main components are magnesium, aluminum, calcium composite silicate, belong to inorderable salts. In addition, containing some sulfates and impurities, transparent powder is a new type of functional transparent filler, with high transparency, good hardness, excellent color, high gloss, good resistance to collapse and less dust when used and so on. Widely used in oily furniture paint, decoration paint, adhesive, ink, and plastic. At first transparent powder was only used in oily wood paint, in more than 10 years, the market from strange, understand, careful use, familiar, a large number of applications, and now widely used. Transparent powder has undergone a revolutionary change.
, the classification and characteristics of transparent powder
transparent powder is divided into crystalline water and crystalline water-free varieties. The variety of crystalline water refers to the molecular structure of the product contains chemical structure water (i.e. H2O), its volatile parts are generally 15%-20%, the volatilization of the amount depends on the crystalline rock itself, but also depends on the control of the production process. In general, volatile varieties have relatively high transparency, so many technicians worry that volatiles will not affect the use and effectiveness of paint? In fact, the real impact of paint quality is the physical water of transparent powder, that is, surface water, physical water will participate in some direct or indirect reactions, affecting the use and performance of the coating, and most transparent powder production enterprises have their physical water control below 0.5%, which in the case of ensuring its transparency to maintain other performance of the product, such as dispersion, anti-fog, dryness, side effects and so on. However, transparent powder containing crystalline water in the process of use, such as improper treatment easy to absorb moisture, the phenomenon of coagulation, must be used to achieve normal dispersion effect. In response to this production enterprises are also improving, the current occurrence of this phenomenon is also less, another point, transparent powder although good transparency, but it is also like gas-phase silicon dioxide, there is a certain blue light phenomenon, in some dark substrates if the construction is too thick or excessive one-time use, easy by the blue light phenomenon caused by fog, whitening, which is also some enterprise technicians do not want to see the phenomenon, so in use also subject to some limitations.
varieties without crystalline water are no longer explained, the main ingredient is SiO2, the content of more than 90%, for natural crystalline quartz processing mixed powder, its whiteness is mostly lower than the varieties containing crystalline water, excellent transparency, especially in the polyurethane system, better transparency, it has high temperature, weather resistance, acid-alkali resistance, high insulation characteristics.
It is characterized by the finished paint will not produce blue light, good re-coating, overcome the ills of crystalline water varieties, but its color and polishing than crystalline water varieties slightly worse, stability and storage is better. Varieties without crystalline water because of its relatively high hardness, so the production enterprises in the production process is relatively difficult, electricity consumption and so on is also relatively rising, so its comprehensive cost is higher than the varieties containing crystalline water, and in the processing process, its dust content, noise is also higher than the varieties containing crystalline water, all kinds of defects are doomed to be limited in its application, only in some special or relatively high requirements, the cost limit is not limited to use in the formula, it can reflect different performance!
5, the use of transparent powder
1, wood coating: can be applied to PU, PE, NC transparent wood paint primer and UV light curing paint to increase transparency, oil run, hardness, improve resistance to collapse, can also be used for water-based wood paint, oily white paint and other solid color primer to improve the paint film gloss and antioxidant, increase the fluidity of lacquer fluidity.
2, oily adhesive: can be used in adhesives to improve solid content, adhesion, hardness, dryness and other physical and chemical properties.
3, artificial stone: in the stone can improve its transparency, gloss, hardness, reduce the comprehensive cost.
4, plastic fillers: improve product hardness, refrater resistance, acidity and alkalinity, electrical insulation, dimensional stability, creep resistance, crack resistance, high transparency, good toughness.
6. The problems that transparent powder should pay attention to in use
(i), transparent powder compared with traditional fillers, has the following significant characteristics:
1, high transparency: due to the refringing rate of transparent powder itself and the vast majority of synthetic resins The refring rate is very close, so the high filling amount of transparent powder basically does not affect the transparency of the finished product;
2, high hardness gloss: due to its low oil absorption rate, high solidity, can improve the surface gloss, hardness and wear-resistant scratch resistance of the product, at the same time, also partially affect the sand performance of the product
; Compared with other products with the same amount of oil absorption, its sedativeity is significantly better than that of other products, which can improve the appearance of the product.
4, good anti-collapse: the product is good filling, hardness than talcum powder and other slightly higher, deformation, shrinkage is small, add paint and other products with high filling, anti-collapse function, even for the thicker wood-printed substrate also has a better filling effect.
5, good dispersion: uniform granularity, good fineness, a variety of resins have a good immersion, compatible, no sanding, roller grinding, ordinary high-speed dispersion machine high-speed (1200-1500r/min) dispersed 10-18 minutes or so can reach the desired fineness.
6, strong stability: this product is an inert material, with strong acid resistance, strong alkali corrosion, high temperature resistance, flame retardant properties and other advantages, with a variety of resins, additives and solvents will not occur chemical reactions, storage stability is good. Due to special treatment, very little dust is raised during use, which is more environmentally friendly, hygienic and safer to use than traditional transparent fillers. Can be used in a variety of fireproof, flame retardant coatings.
(ii), the use of several issues of concern
1, for products containing chemical structure water (i.e. crystalline water), please avoid the use of high temperature baking related products (such as paint, etc.), glass transparent powder in the application is not subject to this restriction, and has insulation, high temperature resistance and other characteristics.
Products containing crystalline water are made of paint, paint liquid micro-blue phase, the production of paint for dark substrates, paint, such as construction is too thick and easy to whiten, please use with other powders, or after the experiment to determine the appropriate amount of added use.
2, due to the high hardness of transparent powder (especially glass-type transparent powder), smoothness will cause the paint film difficult to polish, the need to adjust the formulation system, adjust the drying speed of the paint film, appropriately increase the cost of the polishing agent. 3, transparent powder oil absorption is low, anti-sinking is relatively difficult. In the coating system, relative to resin, talcum powder, zinc stingate and other raw materials, transparent powder precipitation is relatively fast, because its proportion is larger than resin, low oil absorption value, so precipitation is fast, requiring the anti-sinking system to make appropriate adjustments to adapt to the market requirements for product anti-precipitation.
4, transparent powder containing crystalline water is prone to water loss, but also easy to absorb moisture, so its packaging must be moisture-proof, stored in a cool and dry place. The requirements for products in the storage and transportation process are also relatively high.
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