Filler cost-effectiveness

This has historically involved only minimal use of chemical additives. The product is usually unsized and, because of its low cost, the use of polyelectrolytes for retention is not usually cost-effective. However, this situation is changing as a result of the trend towards limited filler inclusion and also the increased use of deinked waste paper. Newsprint is usually made in an acidic system due to the naturally low pH of groundwood pulp but, as more recycled fibre is used, the process may eventually become neutral. 

Modern C3 materials for automotive applications, such as components of the car body, are synthesized according to the flow scheme of Fig. 9.2. Here an integrated synthesis of both filler and binder components is taken as a cost-effective approach. In high-tech applications it is more customary to independently optimize the preparation of the fiber component [15,19, 20, 36, 37] and then the C3 synthesis in separate processes with extensive quality control measures in-between. 

More than 800 million pounds of EPM and EPDM polymers were produced in the United States in 2001. Their volume ranks these materials fourth behind styrene-1,3-butadiene copolymers, poly( 1,4-butadiene), and butyl rubber as synthetic rubbers. EPM and EPDM polymers have good chemical resistance, especially toward ozone. They are very cost-effective products since physical properties are retained when blended with large amounts of fillers and oil. Applications include automobile radiator hose, weather stripping, and roofing membrane. 

Other mineral additives have been used for many years as functional extenders and fillers in adhesives and sealants. These include kaolin (hydrated aluminum silicate), bentonite (hectorite clay), talc (magnesium silicate), and attapulgite (hydrated magnesium aluminum silicate) additives.1213 Kaolin and talc are considered to be viscosity thickeners whereas attapulgite is more of a conventional thixotrope. They are considered to be very cost-effective rheological additives. 

Tribasic calcium phosphate is widely used as a capsule diluent and tablet filler/binder in either direct-compression or wet-granulation processes. The primary bonding mechanism in compaction is plastic deformation. As with dibasic calcium phosphate, a lubricant and a disintegrant should usually be incorporated in capsule or tablet formulations that include tribasic calcium phosphate. In some cases tribasic calcium phosphate has been used as a disintegrant. It is most widely used in vitamin and mineral preparations as a filler and as a binder. It is a source of both calcium and phosphorus, the two main osteogenic minerals for bone health. The bioavailability of the calcium is well known to be improved by the presence of cholecalciferol. Recent research reports that combinations of tribasic calcium phosphate and vitamin D3 are a cost-effective advance in bone fracture prevention. ... 

These current developments place an emphasis on the perfection of filler technology. This has resulted in the creation of many very high quality materials which are too expensive to use in most applications. There is a need to develop materials which arc substantially more cost-effective but still allow the conservation of matrix materials. This will be driven by environmental concerns. Product life cycle evaluation, an emerging development, will have a strong impact on the choice of fixture technologies and fillers associated with these technologies. REFERENCES... 

The presence of a filler in a polymerization reaction can often produce an improved material. Now, the challenge is to take advantage of these new findings and develop cost effective commercial processes. 

Virtually all polymers deteriorate under exposure to outdoor weathering and solar radiation, but at greatly varying rates. Polymers In solar equipment must maintain optical, mechanical, and chemical Integrity despite prolonged exposure to solar ultraviolet radiation. For most outdoor applications of polymers, solar radiation exposure Is Incidental, but for many solar applications, exposure to solar radiation Is deliberately maximized In the equipment design. Transparency Is essential for many of the potentially most cost-effective applications, and conventional approaches to ultraviolet protection such as opaque coatings and fillers are unacceptable. 

As in flat-sheet filtration, the constant flow rate of the bottle filler dictates the nnmber of cartridges to nse. It has been calculated that three 30-inch cartridges (Alter surface of 1.8 m each, flow rate 720 Fh) are required to supply a bottling line operating at 3000 bottles/h or 2250 1/h. Filter membranes must be used for several weeks, or even months, before they become completely blocked in order to make this system cost-effective. 

Fillers significantly increase the tensile properties of polysulfides. This is related to the type of filler, its particle size and the type of cure. A balance of filler particle size and type is required to achieve the optimum wetting and rheology to produce the most cost effective compounds. Consideration must be given to the pH of the filler, since this affects shelf stability or well as cure properties of the compound. Fillers must be inert and insoluble in the sealants s environment. Care must be taken that the filler is adequately dispersed to ensure optimum thixotropy and barrier properties. 

In summary, it is of paramount importance for the papermaker to have a clear idea of the performance attributes which are to be achieved by filler. With that information and a cursory understanding of how the fundamental filler characteristics scale up to application performance, cost-effective paper grade design is possible. 

There are a range of conductive polymers on the market that are based on metal fillers such as aluminum flake, brass fibers, stainless steel fibers, graphite-coated fibers, and metal-coated graphite fibers. However, the most cost effective conductive filler is carbon black. Mention should also be made of... 

TSs offer high thermal stability, good rigidity and hardness, and resistance to creep. It also means that, once cured, the resin and its RP cannot be reprocessed, except by methods of chemical breakdown. For practical purposes, as it has been done for a century, cured TS resins can be recycled most effectively if ground to fine particles. Then they can be incorporated into TSs and TPs, as cost-effective fillers. 

Since it is silica-based, glass fiber for polymer reinforcement could be thought of as a cousin to mineral fillers. But glass fiber is more carefully produced in controlled, uniform, and symmetrical shapes with extremely high aspea ratios, with particle dimensions that are (usually) visible to the human eye. Glass-fiber reinforcement is probably the most cost-effective and most proven way of reinforcing polymers to inaease tensile and flexural modulus and strength. 

The arguments presented in this chapter try not to neglect one key point that choices about fillers and fibers depend not just on the properties they supply, but also on how easily they can be processed, how they interact with the resin and other additives, and how cost-effectively they can be supplied and added to the resin. (Table 8.1 shows generally some of these basic filler/fiber/resin relationships.) Also, the chapter will attempt to address the following questions ... 

In thick, high-volume PO applications such as extruded pipe, standard (20-pm) talcs provide effective stiffness. But finer talc grades may allow reduced resin use by allowing thinner parts with equivalent beam stiffness. Reduced talc particle sizes (near 1 pm), for instance, can create a better balance of properties in thinner parts to help justify increased filler cost that results from the use of very fine talcs. Lower talc loadings may also be possible the newest high-aspect-ratio talcs are said to create the same mechanical properties at 3%-7% loadings in PP than in PP compounds loaded with 20% standard talc. Cases 8.1 and 8.2 cover applications in which different talcs supply these different functional needs [7-10]. 

---