Filled resin systems

The MACT Model point values shown for vapor-suppressed resins applied manually, mechanically or by filament winding/centrifugal casting, are applicable for unfilled resin systems only. For filled resin systems, the non vapor-suppressed point values should be used whether or not the resin contains a vapor-suppressant. Point values shown for vapor-suppressed resins assume a 35% reduction in emissions when such resins are used in an unfilled resin system. Point values for a vapor-suppressed resin used to comply with a MACT standard would be obtained from an equation that uses results of a laboratory test conducted on that resin system. 

The systems can include many options surfiice veil, chopped liners, sprayed resin systems, hoop winding strands, helical winding strands, resin bath, unidirectional tape, woven roving tape, pigmented resin surfaces, wax-resin surfaces, gel coats, BPO catalyst, epoxy resins, vinyl ester resins, filled resin systems, abrasive resin systems, polyester foam, syntactic foam, and charting film. 

UPE resins can be used as clear castings or in combination with particulate fillers or fibres. The resin was developed to meet the demand of lightweight materials in military application. The first functional use of UPE was in radome. Because of the obvious advantages of easy processability and low cost, it was used in a wide range of applications in civil sectors such as tanks, pipes, and electronic gears. Some of the important products based on cast UPE resins are encapsulation of electronic assembly, buttons, door handles, knives, umbrellas, industrial wood and furniture finishing. A filled resin system using limestone, silica, and china clay are used for floor tiles. The major use of UPE is as a matrix for fibre-reinforced composites. Such composites have wide applications in automobile and construction industries such as boats, water-skis and television antennae. Examples of applications of UPE resins are presented in Table 2.7. 

Although silanes predominate as adhesion promoters, the use of titanate, zir-conate, and other agents is growing. Titanate adhesion promoters can provide a dual function of improving the dispersion of fillers and enhancing bond performance. Titanates have been used predominantly to modify the viscosity of filled resin systems. A small percentage of titanate in a heavily filled resin system can reduce the viscosity significantly. 

Thixotropic filled resin systems such as sealants and pastes are generally not Newtonian fluids because their viscosity falls as the shear rate increases. These materials show non-Newtonian behavior. The flow of molten polymer is generally non-Newtonian because it produces lower viscosities at higher shear rates. 

Composite covers with cast functional layers are applied in the press section or in calenders. Typically, mineral filled resin systems are applied onto a fiber reinforced... 

Styrene analysis is usually a simple and reliable method. Analogous to DSC analysis, however, the resin content has to be determined by incineration to obtain a quantitative statement for fiber reinforced or filled resin systems. Quantitative analysis becomes difficult when non-reactive components and components not separable by incineration (e.g., elastomer fillers or polymer fibers) are present. Moreover, when a large number of components is involved, complicated chromatograms with peak overlapping will make analysis difficult. 

Electrical properties of filled resin systems can also be improved by filler treatment. A filler particle is naturally hydrophilic via its metal hydroxide... 

Other filled resin systems that require a coupling agent include highly filled sand cores with ftiran urea-formaldehyde and urethane resins in the foundry industry highly filled polymer concrete where polyester and epoxy binders are used to bond aggregate and cultured marble, cultured onyx, and cultured granite, where a highly filled thermoset resin is used to bond and aluminum trihydrate. 

The concept of a metal filled resin is useful in the tool and die industry, where in certain applications the costly, time-consuming fabrication of solid metal molds is being replaced by relatively inexpensive, easily fabricated metal filled resin systems. Table 8 shows how silane coupling agents can offer strength improvement in this composite system. ... 

Electrical properties of filled resin systems are also improved by filler treatment. Filler particles are naturally hydrophilic via their metal hydroxide surfaces, and the particles naturally seek to agglomerate with each other, and so transport electrical charges through resin composite. Treatment with silane-coupling agent alters the chemistry of the filler surface, allow better dispersion of the filler throughout the resin matrix, and imparts improved electrical properties to the composite. Table 15.13 indicates the improved electrical properties of a quartz-fiUed epoxy resin system with 0.3% silane admixed into the formulation. Improved insulation values, including reduced dielectric constant and reduced dissipation factor, are also denoted. 

Other filled resin systems that require a coupling agent include highly-filled sand cores with furan,... 

In addition to electrical uses, epoxy casting resins are utilized in the manufacture of tools, ie, contact and match molds, stretch blocks, vacuum-forrning tools, and foundry patterns, as weU as bench tops and kitchen sinks. Systems consist of a gel-coat formulation designed to form a thin coating over the pattern which provides a perfect reproduction of the pattern detail. This is backed by a heavily filled epoxy system which also incorporates fiber reinforcements to give the tool its strength. For moderate temperature service, a Hquid bisphenol A epoxy resin with an aHphatic amine is used. For higher temperature service, a modified system based on an epoxy phenol novolak and an aromatic diamine hardener may be used. 

Figure 12-8A. Piston rings. The piston rod is manufactured from heat-treated stainless steel and is coated with wear-resistant overlays, such as ceramic, chromium oxide, and tungsten carbide applied by plasma techniques. Piston rod cross-head attachment has mechanical preloading system for the threads. Rider rings and seal rings are manufactured from PTFE filled resins fillers are matched to the gas, piston speed, and liner specifications. Typical fillers are glass, carbon, coke, or ceramic. (Used by permission Bui. BCNA-3P100. Howden Process Compressors Incorporated. All rights reserved.)...

For thermoplastic composites, results of flammability tests are generally reported on the basis of oxygen index values and/or UL-94 ratings (e.g. (11-12). The general problems associated with composites and multicomponent systems have not been addressed in depth and published data pertain primarily to specific glass-filled resins offered by manufacturers, or to composite systems designed to meet the specifications of a particular end use. 

Thermal expansion differences exist between the tooth and the polymer as well as between the polymer and the filler. The tooth has a thermal expansion coefficient of 11 x 10-6/°C while conventional filled composites are 2-4 times greater [63, 252], Stresses arise as a result of these differences, and a breakdown between the junction of the restoration and the cavity margin may result. The breakdown leads to subsequent leakage of oral fluids down the resulting marginal gap and the potential for further decay. Ideal materials would have nearly identical thermal expansion of resin, filler, and tooth structure. Presently, the coefficients of thermal expansion in dental restorative resins are controlled and reduced by the amount and size of the ceramic filler particles in the resin. The microfilled composites with the lower filler loading have greater coefficient of thermal expansions that can be 5-7 times that of tooth structure. Acrylic resin systems without ceramic filler have coefficients of thermal expansion that are 9 times that of tooth structure [202-204, 253],... 

On-aircraft repairs of composite using a rapid-cure resin system of composite component with UV light irradiation based on TRI patenP have been developed by the U.S. Air Force Research Laboratory. Alternating layers of the acrylate-based resin system and woven fiberglass (the widely used wet la)mp procedure) are applied to fill the hole and form a UV curable composition. The width of the patch can be up to 2 ft (0.6 m) and the depth as much as 0.2 in. (5 mm). The cure time using a 400 W UVA lamp is reported to be 20 min. Although it is essentially a depot repair, it can be done field when necessary to return an aircraft to service. Because of the necessity to cure relatively thick repair patches, Us-acylphosphine oxide was used as a photoinitiator. An example of the patented UV curable resin system used for the repairs is in Table 11.1. 

It should be pointed out that diluents are not the only way to lower the viscosity of filled epoxy resins systems. Surface active agents can also be added to the system. They provide better wetting of the filler by the epoxy resin matrix. This can lead to substantial viscosity reduction for systems having equivalent filler concentration. The surface active agent, in turn, could also be used to produce formulations with higher filler loading at equivalent viscosity. These surface active agents are discussed in Chap. 10. 

Benzoyl peroxide is an antimicrobial and keratolytic agent used in the treatment of acne it is also added to some foods. It is a catalyst for cross-linking in the production of plastics and is occasionally used in acrylic resin systems (for example composite dental fillings, dental prostheses) in which it is formed during the cross-linking process. 

Expansion of gas-filled beads by application of heat or expansion of these beads in a polymer mass by the heat of reaction, e.g. expansion of polystyrene beads in a polyurethane or epoxy resin system. 

AMS 3699-83 Resin System, Epoxy, Carbon Microballoon Filled, 135 C (375 F) Cure, 7 pp... 

Covers a two-part epoxy-resin system in the form of a bisphenol "A" epoxy resin filled with fumed silica and carbon microspheres and a separate aromatic diamine curing agent. 

Fusabond [DuPont]. TM for resin used for coupling in mineral-filled polypropylene systems. Works best with long glass fiber systems. The resins act to bond the filler into the polymer matrix. Also improves surface wetting and dispersion of the filler. It enhances tensile and impact strength of the composite. 

---