Precipitated calcium carbonate adhesives sealants

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. 

Chem. Descrip. Precipitated calcium carbonate CAS 471-34-1 EINECS/ELINCS 207-439-9 Uses Reinforcing agent, filler for rubber (SBR, NR, NR, CR), PVC plasti-sols, paints/coatings, extruded and molded goods, adhesives, sealants, sundries... 

Good dispersion of the precipitated calcium carbonate in the adhesive or sealant is essential to optimize the reinforcement and rheological properties. Frequently blends of ground and precipitated calcium carbonates are used to optimize cost/performance. The ratio of ground to precipitated typically ranges from 1 1 to 3 1. 

Air floated and water-washed grades of kaolin are widely used in paper, packaging and construction adhesives based on starch, emulsion and latex based waterborne systems. They are also used in fabric adhesives, mastics and caulking compoimds. Calcined kaolin is used as a low moisture reinforcing agent in one or two part construction and automotive sealants based on butyl, methane and silicone elastomers. Calcined kaolin is less acidic and so can be used with precipitated calcium carbonate in polysulfide sealants. Typical loading of kaolin fillers are 5 to 25% in adhesives, 5 to 20 % in sealants, and 25 to 50 % in mastics. 

Statt, B.K. et al, 1992, "Precipitated Silicas in Adhesives and Sealants", Supplier Short Course on Additives, Adhesive and Sealant Council, Washington, DC, April, pp IV, 1-30. Tapper, M., Mathnr, K, 1992," Use of Calcium Carbonates in Sealants", ibid, pp n, 1-19. Washabaugh, F.J., 1992, "Kaohn, Talc and Attapulgite", Supplier Short Course on Additives, Adhesive and Sealant Council, Washington, DC, April, pp III, 1-19. 

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