Flow Control Fillers

Uses Extender, pigment, flatting agent for paint systems filler, flow control agent tor NR, SR, latexes, polymers Features In paints, offers inc. contrast ratios improves reflectance and decreases yellowness exc. salt spray resist, and fast grinding in primers disperses easily tor improved processability improves thermal shock resist. 

Uses TiOj extender, pigment for papermaking filler, flow control agent for NR, SR, latexes, polymers dispersant Regulatory Canada DSL Manut/Distrib. Thiele Kaolin Trade Names Burgess No. 30 Karaya Karaya gum. See Karaya (Sterculia urens) gum Karaya (Sterculia urens) gum CAS 9000-36-6 EINECS/ELINCS 232-539-4 FEMA 2605 INS416... 

The higher molecular-weight soHd epoxy resins are used in formulations that usually consist of a resin, hardener, reinforcing filler, pigments, flow control agents, and other modifiers. In addition to using conventional hardeners in these formulations, epoxy resins can also be hardened with other resins, ie, acryhcs or polyesters. 

It should also be emphasized that the epoxy resins are only building blocks in the development of epoxy-based adhesives. The formulation will ultimately involve one or more epoxy resins curing agents modifiers, such as plasticizers, flexibilizers, accelerators, stabilizers, and flow control agents and fillers. In general, flexibility can be controlled by the parameters shown in Table 3.8. 

Fillers are often useful in epoxy-polyamide adhesives (41). Fillers aid flow control—particularly at elevated temperatures. Other properties contributed by fillers are exhibited in the cured system. For example, they can increase the modulus of elasticity, modify the coefficient of thermal expansion, increase heat resistance, and even affect bond strength. Of course, the excellent wetting properties of polyamides Increase the dispersion efficiency of these fillers. The type of filler selected and the amount used also have a pronounced effect on adhesive quality. A few of these effects are illustrated in Tables VI and VII (37). (See also Table VIII.)... 

Silica, then, is an important part of all or nearly all silicone sealants. If the sealant is clear, silica s probably the only filler. If the sealant is opaque, silica may or may not be present for reinforcement but it s almost always present for flow control. The single drawback to fumed silica is cost therefore, only a minimum quantity is used and there is a continual search for ways to use less. 

Fillers and other additives are used to make molded objects from phenolic resins to reduce shrinkage during cure, improve strength, and provide flow control. Representative materials added are mineral flour, wood flour, nutshell flour, pressed olive stones, lignite, and natural rubber. Crosslinked phenolics containing inorganic or organic fillers are schematically illustrated in Scheme 35. 

Mica belongs to the fillers that are added to phenolic resins in order to reduce their shrinkage during cure, to improve their strength and to provide flow control. Furthermore, mica adds outstanding dielectric properties, high thennal and chemical resistance to phenolics, and it lows their water absorption. 

Although Newtonian behavior is a useful starting point for many systems, more complex behavior is very common, especially in formulated adhesives that often have high solids content, contain fillers and flow controllers, or consist of high molecular weight hot-melts. When materials are non-Newtonian, it is appropriate to refer to the measured viscosities as apparent viscosities in recognition of the more complex rate-dependent behavior. 

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