Precipitated calcium carbonate plastics

Plastics. The fastest-growing use of whiting (microcarbonate fillers) is in the plastics industry where dry, pulverized limestone is used intensively for most types of plastics. Other carbonate fillers, precipitated calcium carbonate, oyster sheU, marble, and wet-ground limestone, are also used. 

Calcium carbonate is one of the most versatile mineral fillers (qv) and is consumed in a wide range of products including paper (qv), paint (qv), plastics, mbber, textiles (qv), caulks, sealants (qv), and printing inks (qv). High purity grades of both natural and precipitated calcium carbonate meet the requirements of the Food Chemicals Codex and the United States Pharmacopeia and are used in dentifrices (qv), cosmetics (qv), foods, and pharmaceuticals (qv). 

Calcium carbonate is a common inorganic compound known as limestone. Calcium carbonate has many applications in industries such as medicine, agriculture, paint plastic and surface coatings etc. The vast majority of calcium carbonate used in industry is extracted by mining process. Pure calcium carbonate (e.g. for food or pharmaceutical use), is synthesized by passing carbon dioxide into a solution of calcium hydroxide slurry. In this process calcium carbonate precipitates out, and this grade of product is referred to as precipitate calcium carbonate (abbreviated as PCC). The common reaction is as follows ... 

Calcium carbonate occurs in nature as hmestone in various forms, such as marble, chalk, and coral. It is probably the most widely-used raw material in the chemical industry. It has numerous apphcations, primarily to produce cement, mortars, plasters, refractories, and glass as budding materials. It also is used to produce quicklime, hydrated lime and a number of calcium compounds. It is produced either as powdered or precipitated calcium carbonate. The latter consists of finer particles of greater purity and more uniform size. They also have many important commercial apphcations. Various grades of precipitated calcium carbonate are used in several products, such as textiles, papers, paints, plastics, adhesives, sealants, and cosmetics. 

Calcium carbide is used to produce acetylene. Some of the other chemicals made with lime include calcium hypochlorite, citric acid, and sodium alkalis. Lime is used to produce precipitated calcium carbonate (PCC), which is a fine-grained form of calcium carbonate. To produce PCC, lime is hydrated to produce slaked lime and the slaked lime is combined with water to produce limewater. Carbon dioxide is added to the limewater, causing calcium carbonate to precipitate as PCC. PCC is used widely in plastics production, papermaking, pharmaceuticals, and the petrochemical industry. 

Calcene [PPG]. TM for a specially prepared precipitated calcium carbonate for use in compounding rubber, paints, and plastics. The particles of grade TM are coated with stearic acid to aid in dispersion. Grade NC is not coated. 

NOTE To obtain plasticizer control data, see Table III (50 pph Ultra Fine Precipitated Calcium Carbonate) for PbO MnO cures respectively. 

Besides mixing different polymers, there are other possible ways to obtain high-impact plastics, for example copolymerization and graft polymerization or use of plasticizers in brittle polymers. These products will not be treated in this section. In the case of PVC-U, addition of ultrafine precipitated calcium carbonate (grain size 75 nm) has excellent impact cmiditioning and surface quality-enhancing effects. 

Chem. Desetp. Precipitated calcium carbonate CAS 471-34-1 EINECS/ELINCS 207-439-9 Uses Filler in pulp/paper, paints, pharmaceuticals, cosmetics, rubber, plastics... 

The calcium hydroxide byproduct is traditionally converted to calcium chloride for which there is a market. However, a significant market is developing for precipitated calcium carbonate (PCC) in several industries. Demand in the US paper industry for PCC is projected to rise to 1.8 million tonnes per annum by 1996, up from only 175 000 tonnes in 1974. Use in the plastics, adhesives, paints and coatings industries is also increasing dramatically. The first acetylene plant producing PCC has recently been successfully commissioned in Dessau, Germany [18]. 

In terms of weight, calcium carbonate is the most important filler for plastics and it is also widely used in rubber and paints. Calcium carbonate is, in fact, much more than chalk (as it is universally described in the plastics industry). The term covers natural chalk, limestone, and marble - and also precipitated calcium carbonate, which has a very fine particle size, is relatively expensive, and offers some interesting properties in polymer compounds. 

Fillers like precipitated calcium carbonate might be used in a plastic composition to reduce the overall cost of the formulation or to improve its optical properties. With fillers such as carbon black (used in tire formulations) or glass fibers (used in fiber-reinforced unsaturated polyester, GRP), the primary role of the filler is to improve the mechanical properties of the composite. 

Abstract A new low density mineral material has been synthesized via a simple, flexible, cheap and easy to control process. This material is a synthetic carbonate produced by carbonation of a solid phase composed of a calcic part and a magnesian part. Typically, its production process includes the calcination of a raw dolomite (general formula CaC03.MgC03) into the oxide form, followed by an at least partial hydration of this oxide and a subsequent carbonation step. This process is thus close to the well-known process used for the production of Precipitated Calcium Carbonate (PCC), a common filler and pigment in plastic, paper and rubber, except that the raw material is a dolomite instead of a limestone. It has to be pointed out that flue gases from different industries can be used as a source of CO2 for the carbonation. 

Coohng water is then circulated and the batch cooled while mixing to 35—40 °C. In some cases, with high-shear input, soft fillers such as calcium carbonate can be added with the resin, particularly with modest levels of plasticizer, improving output. This is infrequently done in the laboratory, other than to simulate a factory procedure. It should be avoided with submicron fillers such as precipitated calcium carbonate, since these often will absorb plasticizer more rapidly than the resin does, leading to intractable lumps. When using ultrafine fillers, lubricants as well as plasticizer should be incorporated first. 

Various additives and fillers may be employed. Calcium carbonate, talc, carbon black, titanium dioxide, and wollastonite are commonly used as fillers. Plasticizers are often utilized also. Plasticizers may reduce viscosity and may help adhesion to certain substrates. Thixotropes such as fumed silica, structured clays, precipitated silica, PVC powder, etc. can be added. Adhesion promoters, such as silane coupling agents, may also be used in the formulation [69]. 

In the North American market, water heaters are almost always made with the cold water inlet and hot water outlet lines coming out of the top of the tank. The hot water outlet opens right into the top of the tank and so draws off the hottest water. The hot water has risen to the top of the tank because of its lower density. The cold water on the inlet side is directed to the bottom of the tank by a plastic dip-tube. In some models the dip-tube is curved or bent at the end to increase the turbulence at the bottom of the tank. This is to keep any sediment from settling on the bottom of the tank. As sediment— usually calcium carbonate or lime—precipitated out of the water by the increased temperature builds up, it will increase the thermal stress on the bottom of a gas-fired water heater and increase the likelihood of tank failure. On electric water heaters the sediment builds up on the surface of the elements, especially if the elements are high-density elements. Low-density elements spread the same amount of power over a larger surface of the element so the temperatures are not as high and lime doesn t build up as quickly. If the lower elements get completely buried in the sediment, the element will likely overheat and burn out. 

Instruct others to maintain a safe distance. Wear self-contained breathing apparatus, eye protection, butyl rubber gloves, and a laboratory coat. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. When the hydrofluoric acid has been absorbed, scoop the mixture into a plastic pail and transport to the fume hood. Slowly add to a pail of cold water. Add an excess of calcium carbonate or calcium hydroxide. Let the precipitate settle for 24 hours. Decant the solution to the drain. Allow the solid residue (calcium fluoride and bentonite) to dry and package for disposal in accordance with local regulations.7,8... 

Hiflex - surface treated calcium carbonate for easy compounding in water pipes, cables, etc. Precipitated USP Grade - 3 grades for pharmaceutical, cosmetic, and food industries 402 - surface modified calcium carbonate for PVC plastisols and other plastics ECC International, Cornwall, UK... 

There are three principal forms of CaC03 used as fillers in plastics— milled, precipitated, and coated. More than 90% of calcium carbonate is used as milled mineral. 

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