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Structural Reaction Injection Molding (SRIM) is generally regarded as a thoroughly developed technology and is currently utilized in many automotive applications; most prominently door panels but also other applications, for example package trays and headliners. The traditional production process involves the placement of a glass fiber mat into a mold prior to injection of a suitable liquid resin system. Upon removal of the part, the glass mat is thoroughly encapsulated by the resin system forming a structural composite material. In the new Long Fiber Injection (LFI) process, the glass fibers are injected along with the resin mixture onto the production mold. This new process demonstrates a new approach to high productivity, low cost manufacture of LD-SRIM composites.

Glass mat reinforced structural polyurethane foam or low density structural reaction injection molding (LD-SRIM) has found a niche in the manufacture of high quality, light weight, automotive, interior trim substrates. Current trends in the automotive industry indicate the need for cost reductions without sacrificing quality. A high productivity LD-SRIM system has been developed which meets this need. This cost reduction is achieved by the incorporation of an internal mold release agent and a 25 % decrease in demold time compared to current LD-SRIM technology. These technological advancements give the trim component manufacturer an increase in productivity by eliminating the time and labor required to apply external mold release and a shorter demold time. These advancements also provide for a significant reduction in the volatile organic compounds and cost associated with external mold release agents.

ICI Polyurethanes has developed a series of structural reaction injection molding resins for automotive interior trim applications. These new resin systems are CFC-free polyurethane foams specifically designed for glass mat reinforcement. These light weight composites can be described as low density structural RIM, LD-SRIM. LD-SRIM can offer a weight reduction of 50% over competitive materials with similar physical properties in applications such as door panels. A LD-SRIM composite with 20% glass reinforcement and a specific gravity of 0.55 g/cm3 has a flexural modulus of 2370 MPa. The LD-SRIM process has several benefits such as the consolidation of manufacturing steps achieved through molding in fasteners or decorative materials and the design flexibility inherent to liquid molding technology.

Cream foam is a polyurethane technology designed for molding foam articles such as automotive headrests or armrests directly into their decorative coverstocks. This process allows for the single step molding of covered foam articles eliminating the secondary step of attaching the cover needed in conventional operations. The advantage cream foam offers over conventional molded foam is that penetration of the stitched seams and foam backing of the coverstock is avoided or controlled. Cream foam technology has improved with the development of a MDI-based polyurethane system that reduces penetration of the foam and fabric bilaminate coverstocks by 25% and the molded foam density by 15%. These improvements result in a cost reduction in the manufacturing of arm or head rests.

Management of manufacturing scrap and post-consumer scrap from automobiles will increasingly influence both the acceptance of plastics and choice of plastics in the automotive industry. Polyurea elastomers made by reaction injection molding (RIM) offer many processing, property and cost advantages desired by the automotive industry but their crosslinked nature has generally implied that the scrap cannot be recycled by a widely used recycling method, thermal processing. Recently introduced ICI Polyurethanes imine-polyurea materials for automotive exterior applications can be thermally processed using extruders into sheets, profiles, tubes, moldings etc. The extruded materials have good mechanical integrity and many end-use applications are possible.

A new polyurea RIM elastomer suitable for molding large parts and offering significant improvements in high temperature properties, impact strength and dimensional stability relative to current automotive grade RIM elastomers has been developed by ICI Polyurethanes (Rubicon Chemicals Inc.). The evolution of RIM materials leading to the development of this innovative product is described herein. Related advances in the in-situ treatment of flaked glass reinforcements leading to improvements in demold toughness, heat sag, and coefficient of linear thermal expansion are also detailed. Physical properties illustrating the benefits of this new polyurea RIM system are compared to amorphous nylon and a polyphenylene oxide/nylon alloy.

Weight reduction with maintained part performance is a continuing trend throughout the automotive industry. Acoustical insulation parts (carpet underlay and dash insulators) are no exception. Several years ago, ICI Polyurethanes led the industry in establishing a molded density standard of 48 kg/m3. Although this is the current production standard, the technology drive is toward even lower weights. Recent technological demonstrations show that molded densities of 35-38 kg/m3 are achievable. In addition to removing weight, acoustical performance can be maintained with no deficiencies in physical characteristics.