Reaction injection molding mold filling

Reaction injection molding (RIM) is a fast, low-pressure, low-temperature, low-cost process for one-step conversion of reactive liquids into large finished solid plastic products. Liquid polyol and liquid diisocyanate are mixed by impingement, pumped instantly to fill a large mold cavity, and polymerize/ cure rapidly to form a thermoset polyurethane product. The cured polymer may be a stiffly flexible product such as automotive bumper covers, front ends, and trim or a rigid foamed product such as furniture and housings (cabinets) for computers, business machines, TY and radio. 

Structural reaction injection molded (SRIM) sandwich panel composites incorporating recycled RRIM granulate have been developed in Europe, comprising two layers of glass reinforcement on either side of a core layer of granulated RRIM. The filling can be composed of either painted or unpainted material and can be preformed to shape before resin injection. 

Monomer and initiatra- are filled into PMMA mold. Temporal and spatial control of polymaizatiort process by means of introductimr and dissipation of heat tatergy and variation of the initiatra- amount Reaction injection molding (RIM)... 

In thermally initiated reaction injection molding the relative slow polymerization starts at elevated temperatures (up to 150 °C) after filling of the microstructured mold inserts with the low viscosity resin. Typical polymerization times necessary for a... 

The matrix polymer must quickly fill the cavity of the mold and wet all fibers in the structural reaction injection molding process. Macosko analyzed the flow in terms of flow of liquid throughout the entire cavity and in terms of... 

Highly filled reformulated versions of thermoplastic polyolefin (TPO), acrylonitrile-butadiene-styrene (ABS), and polycarbonate (PC)/ABS blends are found in bumper applications around the world. Today, TPO dominates this market worldwide. Other than these polymers and blends, thermosets often enter into this market as reaction-injection-molded (RIM) products. 

Bruins PF (ed) (1976). Unsaturated Polyester Technology, Gordon Breach Science, New York. Castro, J (1980). Mold Filling and Curing Studies for the Polyurethane Reaction Injection Molding Process, Doctoral Dissertation, University of Minnesota, Minneapolis, Minnesota. Castro JM, Macosko CW (1982). AIChE J. 28 250. 

Macosko, C. W., RIM Fundamentals of Reaction Injection Molding , Hanser, New York, 1989. The book emphasizes fundamentals and discusses the operations of material delivery, mixing, mold filling, curing, for urethanes and nonurethanes, and reinforced RIM. Additional references are provided with each chapter. 

In reaction injection molding, two liquids that can react with each other are injected simultaneously into the mold. As reaction occurs, the viscosity increases and, for this reason, we want the filling stage to be over before an appreciable amount of reaction has taken place. With reference to Figure 15.22, what should be the minimum value of the constant flow rate Q if the two components are injected in equal concentrations and if the reaction follows second-order kinetics, that is,... 

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