Mineral adhesives

Mineral adhesives include silicates and phosphates for high temperature use and naturally derived products such as bitumen and asphalt. 

Let us now examine changes in mineral adhesion that are related to the choice of drum material [137]. For the separation of powders such as quartz, magnetite, hematite, pyrite, barite, asbestos, and j3-spodumene, the yield of the retained fraction on brass and aluminum surfaces was found to vary from 26 to 50%, and on tin plate and steel from 46 to 66%. The adhesion of these powders to tin plate and steel was greater than the adhesion to brass or aluminum. 

Silicate [12627-13-3] Silicate adhesives Silicate esters Silicate grouts Silicate minerals Silicates... 

Vapors emitted from the materials of closed storage and exhibit cases have been a frequent source of pollution problems. Oak wood, which in the past was often used for the constmction of such cases, emits a significant amount of organic acid vapors, including formic and acetic acids, which have caused corrosion of metal objects, as well as shell and mineral specimens in natural history collections. Plywood and particle board, especially those with a urea—formaldehyde adhesive, similarly often emit appreciable amounts of corrosive vapors. Sealing of these materials has proven to be not sufficiently rehable to prevent the problem, and generally thek use for these purposes is not considered acceptable practice. 

The Hercules viscometer was originally designed for paper and paperboard coatings, but its use has been extended to paints, adhesives, mineral slurries, emulsions, and starch solutions. The iastmment, noted for being robust and rehable, is particularly well suited for quaUty control and product formulation. It is capable of measuting viscosity over a moderate range 1-10 mPa-s) up to high shear rates (115,000 ). A more recent model is the... 

Talc is sold for use in a wide variety of appHcations, including paper (qv), ceramics (qv), roofing, paint (qv), plastics, mbber (qv), cosmetics (qv), pharmaceuticals (qv), adhesives (qv), sealants (qv), and animal feedstuffs (see Feeds and feed additives). In all of these appHcations it is a functional ingredient with specific beneficial properties. Talc is rarely used as a filler because it is much more expensive than alternative minerals such as limestone and clay. 

When freshly mixed, the carboxyHc acid groups convert to carboxjiates, which seems to signify chemical adhesion mainly via the calcium of the hydroxyapatite phase of tooth stmcture (32,34—39). The adhesion to dentin is reduced because there is less mineral available in this substrate, but bonding can be enhanced by the use of minerali2ing solutions (35—38). Polycarboxylate cement also adheres to stainless steel and clean alloys based on multivalent metals, but not to dental porcelain, resin-based materials, or gold alloys (28,40). It has been shown that basic calcium phosphate powders, eg, tetracalcium phosphate [1306-01-0], Ca4(P0 20, can be substituted for 2inc oxide to form strong, hydrolytically stable cements from aqueous solution of polyacids (41,42). 

Plasticizers and Processing Aids. Petroleum-based oils are commonly used as plasticizers. Compound viscosity is reduced, and mixing, processing, and low temperature properties are improved. Air permeabihty is increased by adding extender oils. Plasticizers are selected for their compatibihty and low temperature properties. Butyl mbber has a solubihty parameter of ca 15.3 (f /cm ) [7.5 (cal/cm ) ], similar to paraffinic and naphthenic oils. Polybutenes, paraffin waxes, and low mol wt polyethylene can also be used as plasticizers (qv). Alkyl adipates and sebacates reduce the glass-transition temperature and improve low temperature properties. Process aids, eg, mineral mbber and Stmktol 40 ms, improve filler dispersion and cured adhesion to high unsaturated mbber substrates. 

Panel filters may use either viscous or dry filter media. Viscous filters are so called because the filter medium is coated with a tacky liquid of high viscosity (e.g., mineral oil and adhesives) to retain the dust. The filter pad consists of an assembly of coarse fibers (now usually metal, glass, or plastic). Because the fibers are coarse and the media are highlv porous, resistance to air flow is low and high filtration velocities can be used. 

Asbestos may be used for improved heat and chemical resistance and silica, mica and china clay for low water absorption grades. Iron-free mica powder is particularly useful where the best possible electrical insulation characteristics are required but because of the poor adhesion of resin to the mica it is usually used in conjunction with a fibrous material such as asbestos. Organic fillers are commonly used in a weight ratio of 1 1 with the resin and mineral fillers in the ratio 1.5 1. 

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