Extender pigment knowledge is introduced

[View:1794 ] [Update:2013-6-15]

    White mineral constitution is pigment with low refractive index. They each are not identical in composition particle size shape, in high gloss and semi-gloss paint show very small covering power, but they have the "cover" high extinction performance of the paint (air interface), reduce the cost of paint. They are also used to control the luster, markings, suspension, viscosity, etc. Body paint the main types of the carbonate, silicate, sulphate and oxide.

   Supply inert pigment particle size ranges from 0.01 to 44 mu m have different shapes, including ball, needle, fibrous and flake. Particle shape affects the accumulation of paint, paint film softness, cracking up, etc., particle size and particle size distribution affect the covering power, viscosity, coating porosity, binders, and the demand of surfactant, luster, fineness, etc. Whether extender pigment and binders react in relation to salt spray, foam, resistance to corrosion and cracking.

   And studies have been reported using an inert pigment replace another extender pigment and the best way to get quite a performance. Research found that when using an inert pigment replace another extender pigment in equal weight or volume, will produce significantly different paint performance, such as: viscous resistance, durability, permeability, scrub resistance, stain, paint not infiltration, etc.

   Constitution is paints by grinding ore or split stone shape, or by chemical precipitation and according to the need to be refined and size grading process. Is used to separate their dimensions, wet or dry sieving, centrifugal separation, flotation. The sources of the raw material and processing process will affect the performance of the paint.

Calcium carbonate powder or old:

   The extender pigment is widely used in indoor or outdoor paint to control the luster, mold, thickening, reduce the cost. It in natural and synthetic (precipitation) on the two types have a lot of USES, and its particle size range is very wide, from 0.05 to more than 44 microns.

   Natural calcium carbonate dosage is bigger, because it is cheap, and in some ways is equal to or better than synthetic performance. Coarse level limit for putty, fill holes compounds, metal primers and other products, they need high pigment content, liquidity and rough surface. These levels have low extinction effect. Moderate levels of calcium carbonate particles used in architectural coatings and indoor light or semi-gloss lacquer. Levels of fine particles of calcium carbonate, mainly is the precipitated calcium carbonate, used in printing ink. Products often use two level on the formula to get the balance of the required performance.

   The source of natural calcium carbonate extender pigment is limestone and marble, most level contains 95-99% of the calcium carbonate.

Some level through crushing and air classification. Finer level is by wet grinding and subsidence or centrifugal graded to get different levels in the shape of particles, average particle size, particle size distribution and the purity is very different.

   Natural calcium carbonate extender pigment is widely used in indoor construction paint, can be used alone or in combination with talcum powder. Compared with talcum powder, calcium carbonate can decrease the pulverization rate, improve light color paint color retention and increase resistance to mold. Need special size of the particles, in the application of fine particles has a tendency to craze and large particles can solve this problem, it has a low demand and low activity, these inert pigment used in outdoor also emulsioni paint to improve color retention.

   Calcium carbonate in the coating system play a buffer role. Because the inert pigment is alkaline, it will not be able to with the alkali sensitive colored pigments such as chrome iron and green together, can't and soluble iron or copper salt together, cause contamination. Calcium carbonate can't use the acid catalytic curing of melamine polyester system, because it wants and catalyst.

   As one level, precipitation or synthetic calcium carbonate pigment content from 98% to more than 98%, compared with those of natural calcium carbonate with small particle size and narrow particle size distribution, high oil absorption and brightness. Good levels of particle size can be change from 0.03 to 8 microns, has entered the colloid. According to reports, the interior latex paint and paper coating is one of the best particle size was 0.2 mu m. Precipitated calcium carbonate is used in the maximum extinction effect. Some level surface with rosin or fatty acid treatment, the level and allow more easily with the gloss of product can have no obvious loss of luster. In some formulations, it reduce the infiltration of porous surface, so that increase the sealing effect and decrease the infiltration of paint.

Talcum powder:

   Talcum powder used as rock to different parts of the crystal shape is different, resulting in a physical properties change. Talcum powder is a mixture of several kinds of commonly used specific talcum powder paint performance of goods is decided by the structure of the type or types of compounds, the average particle size and particle size distribution. Since most talcum powder is mainly fibrous or flaky. This is the basis of the general classification. Fibrous talcum powder is usually regarded as the best outdoor durability and pigments suspended, but there are some shortcomings in terms of liquidity and smoothness. Laminar talcum powder coating, coating with superior liquidity and smoothness and enamel does not penetrate. It also increases the "lubricant" of coating and printing ink. Less granular talcum powder, has the best adhesion force and grinding performance, indicating that it can be used in the grinding of sealer and 2 way pulp.

   Talcum powder made from many levels, each kind of design has a specific purpose and objectives. Particle size ranging from coarser lower oil absorption to "super fine" high oil absorption, high fineness to 7. Also have grade talcum powder, surface treatment has low oil absorption, fineness scraper for 6 to 7, with the light in the enamel. Talcum powder has many desirable properties, both used in paint and water-based paint, dry film for high brightness and color. Talcum powder wetting and dispersion is very easy, in all of the liquid paint, such as organic solvent alkyd and water, stirring speed often needs no more than moderate speed. Its suspension is also very good, and help other pigments suspended.

   Coarser level in some need to rough paint film, such as wall primer, intermediate layer and paint markings. Smooth level (fineness scraper for about 4) is commonly used in architectural paint, as well as general purpose constitution of paint. Fineness scraper for 5-7 ultrafine talc powder is used in control and half light gloss enamel, consistency and sag. Talcum powder is widely used in joint of cement, the cracks in the packing and caulking agent. These special needs products according to the level of need to use coarse or fine.

   Talcum powder is widely used in various kinds of industrial paint variety, especially the primer and intermediate layer. Primer on steel structure with fibrous talcum powder as pigment all or part of the constitution, it improved the sedimentation, besmear again film strength and flexibility. Many industrial fast drying primer and vehicles using talcum powder paint formula is beneficial. Lamellar silicate including soapstone for the middle layer coating of metal, it tends to improve grinding resistance and water resistance. This is because the flake extended the moisture increase the moisture resistance through the path of the paint film.


   Clay (kaolin) as the inert pigment, its main ingredient is aluminum silicate. First, in the clay is mainly used in papermaking industry, is now being widely used, in recent years, clay has been applied as a inert pigment in the coating industry. Simple air drying and classified products through washing, the strict control of particle size, calcining, and surface treatment and upgrade. Calcination is the most significant of these improvement methods, so the method also entered the mass production.

   Clay particle shape layer mostly flake and hexagonal shape, so the ratio of the width and thickness can be obtained after stratified particles, layered approach similar to sand, pottery clay used caustic soda solution through pressure cooking to improve its porosity, oil absorption, pH and brightness, and density is less than calcined clay, it (including calcining clay, etc.) is known as the "structure" paint, covering capacity, tinting strength can be improved in the coatings and extinction. For example flat emulsioni paint used in the indoors, can replace part of titanium dioxide without affecting quality. Widespread use of the level of its fineness is about 10 microns, all level have different degrees of hydrophilicity, and is almost neutral in chemistry. Oil absorption range from the calcination of 25 to 44 to calcine level 48-58 mu mu m m. The brightness of the different levels of change, reflection coefficient from 80-92%.