Calcined clay filler Calcium carbonate

Typical fillers calcium carbonate, calcinated clay, aluminum hydroxide, magnesium carbonate, magnesium hydroxide, antimony trioxide, calcium borate, huntite, hydromagnesite, zinc oxide, talc, silica... 

Clays - Most commercial clays are classified as hydrous. They are undesirable for use in liquid polysulfide base compounds because of their low pH. However, calcined clays have been found to be satisfactory for use in polysulfide compounds because they are less acidic. The best use of calcined clay fillers is in conjunction with precipitated calcium carbonate fillers to produce a compound with a relatively neutral pH value. For example, calcined clay of the type similar to Icecap K has given good results. 

Mineral fillers are used for light-colored compounds. Talc has a small particle size and is a semireinforcing filler. It reduces air permeabihty and has htde effect on cure systems. Calcined clay is used for halobutyl stoppers in pharmaceutical appHcations. Nonreinforcing fillers, such as calcium carbonate and titanium dioxide, have large particle sizes and are added to reduce cost and viscosity. Hydrated siUcas give dry, stiff compounds, and their acidity reduces cure rate hence, their content should be minimized. 

Carbon blacks are usually used as fillers. The semi-reinforcing types, such as PEP (Past Extmsion Pumace) and SRE (Semi-Reinforcing Pumace) give the best performance (see Carbon, carbonblack). To lower the cost and improve the processibiUty of light compounds, or to lower the cost of black compounds, calcined clay or fine-particle calcium carbonate are used. 

While organo-silane treatments are extensively used in both thermoset and elastomer applications, their use in thermoplastics has so far been somewhat restricted. This is because they do not react with the surface of calcium carbonate, one of the principal fillers used in this type of polymer and because of the lack of a suitable reactive functionality for most of the thermoplastic polymers. Today they are principally used in conjunction with glass fibres, calcined clays, aluminium and magnesium hydroxides, micas and wollastonite. The main thermo-... 

Fillers. Fillers are used to improve strength and stiffness, to lower cost, and to control gloss. The most common filler is calcium carbonate, which ranges in size from 0.07 to well over 50 m. Some forms are treated with a stearic acid coating. Clay fillers, such as calcined clay, improve electrical properties. Glass fibers, talc, and mica improve tensile strength and stiffness, but at a loss in ductility. 

Figure 8.62 shows the compression set of rubber with different fillers at 1 1 proportion to rubber.Fillers, such as precipitated calcium carbonate, whiting, calcinated clay, each of which have limited interaction with the matrix give a substantially lower compression set. As the interaction between filler and the matrix... 

Typical fillers carbon black, calcium carbonate, dolomite, clays, calcinated clays, talc, soapstone, zinc oxide, filmed silica, borates, iron oxide, zinc oxide, magnesium carbonate, pulverized polyurethane foam, barium and strontium ferrites, magnesium aluminum silicate, nylon fibers, quartz in EMI shielding field silver plated aluminum, silver plated nickel, silver coated glass spheres, silver plated copper, silver, nickel and carbon black... 

Calcined clay and precipitated or water ground calcium carbonates of less than 3 ym are the most common fillers used with PVC. Other fillers used are shown in Table XI. 

Fillers increase the strength, impart needed rheological properties, and reduce the cost of sealants. Tensile properties are increased significantly, depending on the type of filler, its particle size, and the type of cure. Improper filler selection can ruin the performance of a polysulfide sealant. Calcium carbonates (wet or dry ground limestone, precipitated), carbon blacks (furnace, thermal), calcined clays, silica and silicate fillers, and rutile titanium dioxide are typical fillers used in polysulfide sealants. Generally, combinations of fillers are used in formulation. Plasticizers improve the working properties while... 

Graft copolymers between unsatnrated acids, especially acrylic acid and maleic anhydride (MA), and polyolefins (PE and PP) are widely used as surface modifiers and compatibilisers, sometimes in combination with bi-functional coupling agents [46], for talc, calcium carbonate and calcined clays. Such polymer coatings include polypropylene-maleic anhydride [47], polypropylene c/s-4-cyclohexene-l,2 dicarboxylic acid [48], polystearyl or polylauryl acrylate [49], polypropylene-acrylic acid, partially oxidised poly(butane diol) [50] and ethylene-vinyl acetate copolymers [51]. Acid-containing products can react with basic fillers. With most other types, they will simply adsorb on to the mineral surface, but they can form esters with some non-basic metal hydroxyls, notably silanols. 

Additives used in final products Fillers barium and strontium ferrites, boron carbide, calcinated clays, calcium carbonate, carbon black, carbon-silica dual phase filler, clays, dolomite, fumed silica, iron oxide, magnesium aluminum silicate, magnesium carbonate, mica, montmorillonite, nickel zinc ferrite, nylon fibers, pulverized polyurethane foam, quartz, silica carbide, soapstone, talc, zinc oxide Plasticizers naphthenic oil, polybutene, aromatic oil, esters of dicarboxylic acid Plasticizers adipates, aromatic mineral oil, paraffin oil, phosphates, phthalates, polyethylene glycol, processing oil, sebacates Antistatics dIhydrogen phosphate of 8-amlnocaprolc add. Iodine doping Antistatics carbon black, quaternary ammonium salt, zinc oxide whisker Antiblocking diatomaceous earth Release propylene wax Slip erucamide+stearamide ... 

The classes of fillers used in formulating polysulfide oligomers are calcium carbonate (wet or dry ground limestone, chalks, or precipitated carbonates), carbon blacks (furnace and thermal), clays (calcined), silica and silicate fillers, and titanium dioxide (rutile is chalk resistant and preferred over anatase). In general, sealants are prepared using a combination of fillers to attain desired properties. 

The most commonly employed fillers in plasticized PVC are the precipitated forms of calcium carbonate (CaCOy) and related minerals such as dolomite (calcium magnesium carbonate). CaCOj fillers are diroated with fatty acids to improve physical properties of PVC, particularly flex life and elongation at break. The effect of calcium carbonate fillers on fusion properties of PVC is reviewed (47). Other fillers include china clay, calcined clay, asbestos, barytas, talc, alumina and kieselguhr and silicates. Micaceous-talc fillers in PVC which are polyblended with acrylonitrile rubber shows an extraordinary effect. Small amounts improve elongation and energy to break. 

Other fillers - Kaolin and Ti02 are used in alkaline papermaking, but to a much lesser extent that in acid papermaking. Kaolins are cheaper in some eases than calcimn earbonate, and satisfy some filling requirements for alkaline. Calcium carbonate does not opacify well so TiOa must be used for some papers. The extender pigments, especially calcined clay and talc, are used and perform better than calcium carbonate when opacifying is needed. 

Non-black fillers may also be employed, but it is important to use neutral or medium high pH grades such as silane-treated calcined clay, synthetic sodium aluminum silicate, platy talc, neutral pH silicas, diatomaceous earth, hydrated aluminum silicate, calcium meta silicate, precipitated calcium carbonate, and so on. An indication of non-black filler requirements for one point of hardness increase is shown in Table 5.10. 

Calcium carbonate provides a modest increase in volume resistivity in PVC, but very much less than calcined clay. One can expect 10-20 phr to approximately double volume resistivity at constant plasticizer level. Usually, however, loadings of calcium carbonate are accompanied by increases in plasticizer level. For a typical ester plasticizer, the decrease in volume resistivity fiom increased plasticizer offsets, or more than offsets, the decrease from adding filler. This can be avoided by using combinations of calcium carbonate with the minimum needed level of ester plasticizer, plus a secondary plasticizer having good electrical properties, such as chlorinated paraffin (Paroil , Dover Chemical) or polymerized aromatic oil (Kenflex A, Kenrich Petrochemical). These approaches are typically used in jacket compounds having insulation resistance specifications. Insulation compounds... 

At significant levels of flammable plasticizer, highly FR vinyl compositions require not only additives such as antimony trioxide, zinc borate, or proprietary combinations, but also replacement of calcium carbonate or calcined clay with an FR filler such as ATH or BMC. Results in flame tests are generally enhanced by coating the FR filler to improve dispersion and surface contact with the vinyl matrix and by fine particle size. These factors favor development of char with poor thermal conductivity, and probably promote release of water of hydration to the flame. 

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