Diluent fillers

For a number of purposes the unmodified epoxide resins may be considered to have certain disadvantages. These disadvantages include high viscosity, high cost and too great a rigidity for specific applications. The resins are therefore often modified by incorporation of diluents, fillers, and flexibilisers and sometimes, particularly for surface coating applications, blended with other resins. 

Most epoxy formulations contain diluents, fillers or reinforcement materials, and toughening agents. Diluents may be reactive (mono- and diepoxides) or nonreactive (di-n-butyl phthalate). Toughening (flexibilizing) agents such as low-molecular-weight polyesters or... 

Lactose has a sweetish taste, and is used extensively in the pharmaceutical industry. It is the second most widely used compound and is employed as a diluent, filler or binder in tablets, capsules and other oral product forms, a-lactose is used for the production of lactitol, which is present in diabetic products, low calorie sweeteners and slimming products. As lactose is only 30 per cent as sweet as sugar it is used as a sugar supplement, and also in food and confectionery. It is used in infant milk formulas. 

Table 1 List of commonly used tablet diluent/fillers ...

Microcrystalline cellulose Glidant 0.2-0.5 Primarily used as diluents/filler... 

Cadila Laboratories Ltd. of Ahmedabad, India have developed an expert system for the formulation of tablets for active ingredients based on their physical, chemical, and biological properties. The system first identifies the desirable properties in the excipients for optimum compatibility with the active ingredient and then selects those that have the required properties based on the assumption that all tablet formulations comprise at least one binder, one disintegrant, and one lubricant. Other excipients such as diluents (fillers) or glidants are then added as required. 

Numerous thermal analysis studies have been performed by other groups on resin composites, which are used for small anterior restorations that do not experience substantial stress and with caution for posterior teeth because of concern about wear [1-3]. The polymer matrix contains the oligomer bis-GMA (bisphenol A-glycidyl methacrylate) or urethane dimethacrylate, and triethylene glycol dimethacrylate is a diluent. Filler particles are silane-coated for chemical bonding with tire matrix. Free-radical polymerization is carried out by chemical... 

One-part epoxy adhesives include solvent-free liquid resins, solutions in solvent, liquid resin pastes, fusible powders, sticks, pellets and paste, supported and unsupported films, and preformed shapes to fit a particular joint. Two-part epoxy adhesives are usually comprised of the resin and the curing agent, which are mixed just prior to use. The components may be liquids, putties, or liquid and hardener powder. They may also contain plasticizers, reactive diluents, fillers, and resinous modifiers. The processing conditions are determined by the curing agent employed. In general, two-part systems are mixed, applied within the recommended pot life (a few minutes to several hours), and cured at room temperature for up to 24 hours, or at elevated temperatures to reduce the cure time. Typical cure conditions range from 3 hours at 60°C to 20 minutes at 100 C. ... 

The processing behavior (mainly viscosity and substrate wetting) and other properties of an epoxy system can be modified by diluents, fillers, toughening agents, thixotropic agents, etc. Most commercial epoxy resin systems contain modifying agents. 

Raw limestone is used to produce whiting (ground limestone) as an economical diluent filler in rubber compounding. It is also used as a feedstock to manufacture precipitated calcium carbonate, which is also used as a little more costly, but better, filler for extending a rubber formulation. 

Powdered taic is another economical diluent filler however, it is commonly used instead of ciay or ground iimestone because talc possesses some lubricity properties that allow it to function as a processing aid. Also, talc particles are platelets in shape, which can impart a better barrier to gas permeability than either clay or whiting. 

Other economic diluent fillers, such as clay, whiting, and talc, are available for use in rubber. 

There are but a few producers of ground coal, but there is no significant history of shortages either. Other economic diluent fillers are usually readily available. 

Most talcs and diy-groimd calcium carbonates are degrading fillers beeause of their large particles size, although the planar shape of the talc particles eontributes some improvement in reinforcement potential. The soft elays would fall into a class of diluent fillers that do not eontribute reinforeement, yet are not so large that they degrade properties. 

Plasticizers and oils, which can be incorporated in extremely large quantities into certain elastomer compounds, are commercially important for two main reasons. They depress the glass transition temperature and hence improve the working temperature range of an elastomer selected on the basis of other properties. Secondly, they allow the incorporation of more diluent filler than the surface adsorption properties of the polymer would normally allow, hence reducing the volumetric cost of the compound. 

Chem. Descrip. Partially hydrogenated soy and cottonseed oils Uses Diluent, filler, binder, lubricant, disintegranL solubilizer, carrier, emulsifier, moisturizer, and emollient in phamn. (tablets, capsules, suppositories, emulsions, ointments) moisturizer, lubricant in cosmetics (creams/lotions, lip and sun care preps.)... 

This is the economical filler par excellence, in ground, air floated and precipitated forms. It is used mainly as a diluent filler, although suitably treated precipitated types have a certain reinforcing effect. Because calcium carbonate is attacked by acids, even weak acids, its use should be avoided in compounds where the finished product could be in contact with these chemicals. 

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