Molding reinforced reactive injection

LRMR Reinforced liquid reaction molding (now reinforced reactive injection molding, RRIM)... 

This technology was first commercially applied to polyurethane blend [121] and patented as Rimplast (for Reactive Injection Molding), but many polymers have since been blended with polysiloxane thanks to this method polyethylene [122], polypropylene [122,123], polyamide [124-130], polyesters [128,131-133], poly(phenylene ether) [134], fluorocarbons [135] and many more. Many of them include reinforcing fillers such as fumed silica. The silicone base involved can moreover contain reactive groups such as the epoxy group [136,137]. A typical silicone base useful for these blends was de-... 

Almost 15 thousand tons of polyurethanes were used as binders for sand in foundries in 1978 but the principal non-foam in sltu-polymerizatlon of urethanes was used for reactive injection molding (RIM) and reinforced RIM (RRIM) of relatively large automotive parts.— Comparable techniques without the use of a molding press were used for the production of mortars and for maxillofacial prosthodontlcs, i.e., the replacement of facial features. 

Reinforced polyurethane resins are often used in a molding process called reactive injection molding (RIM), also known as resin-transfer molding. Polyurethanes are selected for their low viscosity and rapid polymerization. Reinforced applications include large automotive parts and building components. 

In bionanocomposites, the reinforcement content is very low, so they can be processed by the same methods used for the pure polymers. These methods are mainly limited by the fusibility of the polymer, nature of the reinforcements, and their thermal resistance (if melt processing methods are used). The most common methods are extrusion, injection molding, casting, and compression molding, with reactive extrusion a potential option [22, 59, 123, 130]. More information... 

This article is an overview of the novel technology of self-reinforced LCPs with polyesters, poly(ethylene terephthalate) (PET) and poly(ethylene naphtha-late) (PEN) [10-13, 21, 23], LCP/polyester blends in a polyester matrix form in situ fibrils which improve the mechanical properties. LCPs have an inherently low melt viscosity, and provide LCP/polyester blends that effectively lower the melt viscosity during melt spinning [24], and fast injection-molding cycles. The miscibility between the LCP and polyesters can be controlled by the degree of transesterification [25] in the reactive extrusion step, and fibril formation in LCP-reinforced polyester fibers has been studied. 

The adhesion of thermoplastic to glass cannot be explained by copolymerization of the coupling agent with the matrix. The polymers have essentially fully reacted. Chemical reactivity on the polymer backbone is now of interest. The picture is also more complex in that the number of polymers to be reinforced is much larger than for the thermosetting materials. Virtually every polymer which is being injection molded is also being used in its reinforced form. 

The latest trend in foamed composites is automotive structural parts produced by the SRIM (structural reaction-injection-molding) process. The SRIM process is a method of the reactive liquid injection molding (i.e., LIM). LIM includes RIM (reaction injection molding), RRIM (reinforced RIM) and RTM (resin transfer molding). IX M (Liquid Composite Molding) is a relatively new technical term which includes SRIM, RRIM and RTM (Resin Transfer Molding). 

When compared to injection molding (IM) that processes a plastic compound, RIM uses two liquid PUR chemical monomer components (polyol and isocyanate) that are mixed to produce the polymer (plastic). Additives such as catalysts, surfactants, fillers, reinforcements, and/or blowing agents are also incorporated in the reactive system that produces the basic polymer. Their purpose is to propagate the reaction and form a finished product possessing the desired properties (Table 5.9). 

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