Reaction injection-molding technology

The sheer activity of these new nickel norbornene polymerization catalysts and their very rapid polymerization rates makes them potential catalysts for a new nor-bornene-RIM (reaction injection molding) technology to afford a saturated, oxidatively stable RIM part rather than the unsaturated ROMP (ring-opening metathesis polymerization) polymer that is the current commercial Telene or Metton . Fig. 4.6 illustrates the concept and also exemplifies the very rapid polymerization rates that are observed. 

Another type of tee mixer involves opposing flows of reactants with outflow through the side exit into a mixing pipe. One example is the impinging jet reactor used in reaction injection molding technology. The Tee mixer, which is frequently used for liquid-phase reactions, is easier to construct and maintain... 

In polyurethane reaction injection molding technology, self-releasing systems are under investigation. Composition of reactive components (polyols and isocyanates) is used to develop systems which do not require release agents. 

The largest segment of the CASE family of polyurethanes are elastomers. Cast polyurethane elastomers reached a new dimension when high pressure impingement mixing led to reaction injection molding (RIM). This technology is used widely in the automotive industry, and reinforced versions (RRIM) and stmctural molded parts (SRIM) have been added in more recent years. 

F. R. Jones, Reinforced Reaction Injection Molding, Handbook of Polymer Fibre Composites, (F. R. James, ed.). Polymer Science and Technology Science, New York (1994). 

Tungsten-based catalysts with a Lewis base promoter are used in the polymerization of dicyclopentadiene also isolated from the C5 stream-cracker fraction.150,155 The product poly(dicyclopentadiene) or Metton resin has unusual physical and chemical properties. It is processed together with elastomers to increase viscosity of the end product by using reaction injection molding (RIM) technology.155... 

Thermoset polyurethanes are cross-linked polymers, which are produced by casting or reaction injection molding (RIM). For cast elastomers, TDI in combination with 3,3,-dichloro-4,4,-diphen5lmethanediamine (MOCA) are often used. In the RIM technology, aromatic diamine chain extenders, such as diethyltoluenediamine (DETDA), are used to produce poly(urethane ureas) (47), and replacement of the polyether polyols with amine-terminated polyols produces polyureas (48). The aromatic diamines are soluble in the polyol and provide fast reaction rates. In 1985, internal mold release agents based on zinc stearate compatibilized with primary amines were introduced to the RIM process to minimize mold preparation and scrap from parts tom at demold. Some physical properties of RIM systems are listed in Table 7. 

Stanford, J.L. Still, R.H. Stepto, R.F.T. In "Reaction Injection Molding and Fast Polymerization Reactions" Kresta, J.E., Ed. POLYMER SCIENCE AND TECHNOLOGY SERIES Vol. 18, p.31 Plenum, 1982. 

Although the product of this early technology was a molten polymer, the rapid polymerization and high molecular weight polyamide product are clearly desirable qualities for a reaction injection molding (RIM) system. 

Quite recently, the activated anionic polymerization of CL has been found suitable for the reaction injection molding (RIM) technology (9-12) and has prompted some new studies (13-15) devoted to update the classical picture of the reaction kinetics (lj>), mostly in terms of potential industrial applications of the RIM process (13-15,17-20). Successful attempts by Hedrick et al. (11,12) to anionically synthesize a series of PCL block copolymers has led to impact-modified RIM nylon... 

Metering and Mixing of RIM Reactants", by Schneider "Reaction Injection Molding and Fast Polymerization Reactants", Polymer Science and Technology - Volume 18. 

The rapid blending of two steams that is achieved by impinging jet technology, as developed for reaction injection molding by Edwards (1984) was adapted for crystaUization by Midler et al. (1994) and further developed by others [examples Mahajan and Kirwan (1996),... 

Catalyst Selection. The choice of catalysts determines not only the rate of PUR formation by means of the fundamental reaction between isocyanates and their partner reactants, but also the contribution of some of the more exotic reactions of the isocyanates. The rate of PUR formation is, of course, of critical importance to the reaction-injection molding and reinforced-reac-tion-injection molding technology. Among the exotic reactions of the isocyanates the following may be worthy of note. 

Emphasis on reaction injection-molding (RIM) technology in the automotive industry to produce automotive exterior parts has created a large potential for thermoset polyurethane elastomers. Reaction injection molding, originally known as reaction casting, is a rapid, one-step process to produce thermoset polyurethane products from liquid monomers. In this process liquid monomers are mixed under high pressure prior to injection into the mold. The polymerization occurs in the mold. Commercial RIM... 

There is no single method for treating polymethane (PUR) waste, due to the different quantities, qualities, mixes, and cleanliness. It is estimated that some 125,000 t of RIM polyurethane is used worldwide, 85% in automotive parts, mainly in bumper fascias. Current technologies for physical recycling of PURs are mainly directed towards flexible and rigid foams, but systems have also been developed for recycling reinforced reaction injection molded (RRIM) PURs, on the... 

RIM molders n. Molders for reaction injection molding (RIM). These types of molders are lightly constructed machines and consists of preformer, clamp, metering unit and mixhead. The preformer types include thermoforming, fiber-directed, knitting, braiding, or a combination of two or more. Herman F Mark (2003) Encyclopedia of Polymer Science and Technology, John Wiley and Sons, New York. 

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