Formulation fillers

Fillers. Addition of fillers is not common in polychloroprene latex formulations. Fillers are used to reduce cost and control rheology, solids content and modulus. However, cohesion and adhesion are reduced. Calcium carbonate, clay and silica are some of the fillers than can be added. Alumina trihydrate is often used when resistance to degradation by flame is important. 

In some formulations filler or extender resin can be used—partly for economy and partly to reduce the viscosity (especially for harder products, with low plasticizer contents). Often, however, the particle sizes of such additives are of the order of 35 pm, much larger than are the particles of the paste resins (5 to 20 pm), and because of this they cannot be used in formulations for thin coatings—that is, of weights less than 200 gm J. 

The applications and performance characteristics of waterborne epoxy adhesives can be significantly improved by the incorporation of additives and modifiers into the adhesive formulation. Fillers such as calcium carbonate, talc, and silicas are often used to adjust the viscosity of the liquid adhesive and the thermal expansion, modulus, and strength characteristics of the cured adhesive film. 

This chapter, in the view of some readers, may contain information too general to be useful. At the same time, it is very important to stress that the development of high technology products requires adequate effort from the formulators. Fillers produced today are no longer just low cost filling materials but are sophisticated multifunctional additives. They can contribute to a decreased total cost of final products but only if the functions which they were designed for are fully utilized in the product design. This requires sufficient effort and data to produce results. REFERENCES... 

In PVC coating formulation fillers play a role. Filler choice mostly depends on the way the filler affect viscosity. The filler should not absorb the plasticizers nor interfere with the pseudoplastic behavior of the paste which is determined by the resin properties and by the choice of plasticizers. Fillers must be completely dispersed, since the gaps between the coated substrate and the knife are very small. There must be no lumps. Fillers should not interfere with deaeration which is... 

The monomers, comonomers (hardeners), catalysts, and initiators are the components of the formulation that define the thermosetting polymer. Depending on the desired properties of the final material, a variety of other components may be part of the initial formulation. Fillers... 

There are several factors which determine the results of impact modification. They include PVC molecular weight, condition of material surface, materials thickness, temperature of service, type and structure of impact modifier, its particle size and concentration, UV degradation and stabilization of impact modifier, method of incorporation (dispersion mechanism), shell thickness of core-shell impact modifiers, interaction with other components of formulation (fillers, ther-... 

An example WG formulation is shown in Table 12.8. Fillers such as kaolin clays or precipitated silicas are used to dilute the AI and maintain a constant level of Al in the formulation. Fillers are generally mixed with the AI, and the two milled together to achieve intimate mixing and consistent particle size for these two components. 

The arc resistance of a plastic is very dependent upon its molecular structure and the presence and amount of any additives in the formulation. Fillers have a significant effect upon the arc resistance and materials such as alumina and silica can give considerable improvements. Arc resistance is also very dependent on the condition of the surface and is easily reduced by moisture, salts or even grease from skin contact. 

Generally, fillers in sealant formulation are used as additives to boost the viscosity of the sealant and get better gap-filling properties and to reduce the material cost of the sealants. In sealant formulation, fillers cannot affect reinforcement and improved strength. However, they can affect other properties such as water resistance and hardness, etc. The most common filler used in sealant is calcium carbonate, because of its many advantages such as abundant resource, low cost, and stabUity. Other fillers are clays, silica, titanium dioxide, carbon black, and iron oxide. O Table 13.9 lists commonly used fillers in sealant formulations and functions in sealant systems. 

Soybean flour can be used as the main component in adhesive formulations, but it is commonly added as extender for phenolic systems, or blended with casein or other adhesives. They are packaged as dry powders that contain both proteins and carbohydrates. The flour is dispersed in aqueous sodium hydroxide for preparing the adhesive, and also calcium hydroxide is added to extend the open time and to improve water resistance. Soybean glues have a limited water resistance, but recover their strength on drying. They are also susceptible to mold growth, and some fungicides need to be included in the commercial formulations. Fillers are used to reduce cost, but they also lower the performance of the adhesive. Some commonly used fillers are wood and walnut-shell flours, and also clay. 

Alkyds are formulated from polyester resins, cross-linking monomers, and fillers of mineral or glass. The unsaturated polyester resins used for thermosetting alkyds are the reaction products of polyfunctional organic alcohols (glycols) and dibasic organic acids. 

The cured polymers are hard, clear, and glassy thermoplastic resins with high tensile strengths. The polymers, because of their highly polar stmcture, exhibit excellent adhesion to a wide variety of substrate combinations. They tend to be somewhat britde and have only low to moderate impact and peel strengths. The addition of fillers such as poly (methyl methacrylate) (PMMA) reduces the brittleness somewhat. Newer formulations are now available that contain dissolved elastomeric materials of various types. These mbber-modifted products have been found to offer adhesive bonds of considerably improved toughness (3,4). 

Product Concentrate. An aerosol s product concentrate contains the active ingredient and any solvent or filler necessary. Various propellent and valve systems, which must consider the solvency and viscosity of the concentrate—propellent blend, may be used to deUver the product from the aerosol container. Systems can be formulated as solutions, emulsions, dispersions, or pastes. 

Although the use of simple diluents and adulterants almost certainly predates recorded history, the use of fillers to modify the properties of a composition can be traced as far back as eady Roman times, when artisans used ground marble in lime plaster, frescoes, and po22olanic mortar. The use of fillers in paper and paper coatings made its appearance in the mid-nineteenth century. Functional fillers, which introduce new properties into a composition rather than modify pre-existing properties, were commercially developed eady in the twentieth century when Goodrich added carbon black to mbber and Baekeland formulated phenol— formaldehyde plastics with wood dour. 

Plastics. In the plastics industry, the term filler refers to particulate materials that are added to plastic resins in relatively large, ie, over 5%, volume loadings. Except in certain specialty or engineering plastics appHcations, plastics compounders tend to formulate with the objective of optimizing properties at minimum cost rather than maximizing properties at optimum cost. Table 2 fists typical plastic fillers and their uses. 

The processes used commercially for the manufacture of film and sheeting materials are generaUy similar in basic concept, but variations in equipment or process conditions are used to optimize output for each type of film or sheeting material. The nature of the polymer to be used, its formulation with plasticizers (qv), fillers (qv), flow modifiers, stabilizers, and other modifiers, as weU as its molecular weight and distribution are aU critical to the... 

Olefin Polymers. The flame resistance of polyethylene can be increased by the addition of either a halogen synergist system or hydrated fillers. Similar flame-retarder packages are used for polypropylene (see Olefin polymers). Typical formulations of the halogen synergist type are shown in Table 15 the fiUer-type formulations are in Table 16. 

Fillers (qv) are occasionally used in flexible slab foams the two most commonly used are calcium carbonate (whiting) and barium sulfate (barytes). Their use level may range up to 150 parts per 100 parts of polyol. Various other ingredients may also be used to modify a flexible foam formulation. Cross-linkers, chain extenders, ignition modifiers, auxiHary blowing agents, etc, are all used to some extent depending on the final product characteristics desired. 

Formulation Aids. Formulation aids, which include carriers, binders, fillers (qv), plasticizers (qv), and film-formers, are ingredients used in processing to impart a particular physical state or textural characteristic. Table 5 gives an overview of the formulation aids used in the food industry. 

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