Fillers for

Filler for cracks and fissures, particularly in highways. Mixtures of bitumen, heavy oils, polymer or sulfur are used. 

These ahoys are used as fuses, sprinkler system ahoys, foundry pattern ahoys, molds, dies, punches, cores, and mandrels where the low melting ahoy is often melted out of a mold. The ahoys are also used as solders, for the repHcation of human body parts (see Prosthetic devices), and as filler for tube bending. Lead—iadium ahoys are often used to joia metals to glass. 

Various other soft materials without the layer—lattice stmcture are used as soHd lubricants (58), eg, basic white lead or lead carbonate [598-63-0] used in thread compounds, lime [1305-78-8] as a carrier in wire drawing, talc [14807-96-6] and bentonite [1302-78-9] as fillers for grease for cable pulling, and zinc oxide [1314-13-2] in high load capacity greases. Graphite fluoride is effective as a thin-film lubricant up to 400°C and is especially useful with a suitable binder such as polyimide varnish (59). Boric acid has been shown to have promise as a self-replenishing soHd composite (60). 

Flame-Retardant Filler. Demand has increased for Mg(OH)2 as a nonhalogenated, flame-retardant filler for thermoplastics used in the aerospace, microelectronics, and cable and wire manufacturing industries (90). Producers of nonhalogenated, flame retardant fillers include Kyowa, Aluisuisse-Lonza (Magnifin product line), Morton, and a Dead Sea Periclase/Dead Sea Bromine joint venture (91). 

Specific terms have been designated according to the function and composition of various roUs. Steel roUs that impose pressure, transmit heat, and emboss a pattern onto the fabric are known as pattern roUs. Flexible surface roUs that transport the fabric and permit pressure transmission to the fabric are termed bowl roUs or bowls. Bowl roUs are usually larger in diameter than pattern roUs. The material used to make these types of roUs is chosen according to the depth of surface smoothness to be placed on the fabric being calendered, and must be compatible with the pattern roU. Cellulose pulp, cotton, wool, cotton—wool mixtures, com husk, and various polymer materials are used as fillers for the roU surface compound. 

In recent years, synthetic polymeric pigments have been promoted as fillers for paper. Pigments that ate based on polystyrene [9003-53-6] latexes and on highly cross-linked urea—formaldehyde resins have been evaluated for this appHcation. These synthetic pigments are less dense than mineral fillers and could be used to produce lightweight grades of paper, but their use has been limited in the United States. 

In the 1990s, carbon microbeads have been produced by a proprietary process using phenoHc resin. Potential appHcations are lubricants, adhesives, and conductive fillers for plastics, mbbers, and coatings (97). 

Gibbsite is aii important technical product and world production, predominantly by the Bayer process, is more than 50 million metric tons aimuaHy. Alost (90%) is calcined to alumina [1344-28-1 j, Al202, to be used for aluminum production. Tlie remainder is used by the chemical industry as filler for paper, plastics, rubber, and as the starting material for the preparation of various aluminum compounds, alumina ceramics, refractories, polishing products, catalysts, and catalyst supports. 

Eatty bisamides are used primarily to kicrease sHp, reduce blocking, and reduce static ki polymeric systems. Other specialty appHcations kiclude cosolvents or coupling agents for polyamide reskis, fillers for electrical kisulation coatings, additives for asphalt to reduce cold flow, and synthetic waxes for textile treatments (68). Bisamides have been used ki all the traditional primary amide appHcations to kicrease lubricity and have become the amide of choice because of thek better efficiency. Bisamides have the highest commercial value ki the amide market. 

Guanidines. Guanidines (10) were one of the first aniline derivatives used as accelerators. They are formed by reaction of two moles of an aromatic amine with one mole of cyanogen chloride. Diphenylguanidine (DPG) has enjoyed a resurgence ia demand as an activator for sulfenamides and a co-accelerator ia tire tread compounds which employ siUca fillers for low rolling resistance. Guanidines alone show too Htde activity to be extensively used as primary accelerators. There were no U.S. producers as of mid-1996. 

Nonblack fillers such as the precipitated siHcas can reduce both rate and state of cure. The mechanism appears to be one of a competitive reaction between mbber and filler for the zinc oxide activator. Use of materials such as diethylene glycol or triethanolamine prevents this competition thereby maintaining the desired cure characteristics. Neutral fillers such as calcium carbonate (whiting) and clays have Httie or no effect on the cure properties. 

Reinforcing Fillers. Carbon black is by far the most heavily used reinforcing filler for tire compounds. Annual tire usage of all grades of carbon black is estimated to be over three million metric tons aimuaHy. 

Because of its extreme insolubiUty, barium sulfate is not toxic the usual antidote for poisonous barium compounds is to convert them to barium sulfate by administering sodium or magnesium sulfate. In medicine, barium sulfate is widely used as an x-ray contrast medium (see Imaging TECHNOLOGY X-RAY technology). It is also used in photographic papers, filler for plastics, and in concrete as a radiation shield. Commercially, barium sulfate is sold both as natural barite ore and as a precipitated product. Blanc fixe is also used in making white sidewall mbber tires or in other mbber appHcations. 

Gokes derived from resids or blends of resids with other petroleum feedstocks give high GTE values and are utilized as fillers for aluminum anodes and certain specialty carbon and graphite products. The remaining properties differ depending on the final appHcation. Alow ash content is required for... 

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