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Modular window encapsulation of glass using Polyurethane RIM (Reaction Injection Molding) has been very popular in the automotive industry over the last 10 years. RIM offers many advantages in the design of modular windows including: flexibility to design complex shapes with variable wall thicknesses, molded-in attachment studs for easy assembly, and aerodynamic styling. The automotive industry is continually looking for new advancements in technology to increase productivity and decrease the costs of processing parts. A processing advancement using IMR (Internal Mold Release) was introduced into RIM bumper fascia in 1982 with great success. To this day, IMR is an important component for automotive fascia applications. Likewise, window encapsulation with the use of IMR in RIM systems has become a key component in reducing molding cost for automotive windows. The introduction of IMR in RIM for Window Encapsulation offers many potential benefits to the molders of these parts.

Demands in the marketplace have led to the development of lightweight polyurethane elastomer systems for automotive fascia. These products can offer the automotive fascia molder the advantages of RRIM (reinforced reaction injection molding) polyurethane elastomers in a very competitive package. Current refinements developed in filler packages now allow for the application of reinforced RIM systems which exhibit improved surface quality. Moreover, the use of any of a variety of microspheres offers control of shrink and green strength of molded parts. These microspheres may be solid or hollow, rigid or flexible, and range in size from 1 micron to 300 microns. All of these systems exhibit processing characteristics similar to those of established RRIM products, pass on-car performance tests, and compete successfully with competitive lower-cost fascia materials.

Historically, structural reaction injection molding (SRIM) has been restricted to use in non-appearance applications because of problems with glass “read-out” and surface porosity. In this experimental work, a SRIM resin was developed which provides a Class-A surface on an automotive hood after passing through production bonding and painting conditions. The surface quality of production bonded and primed SRIM hoods was measured using LORIA* and D-Sight ** surface analysis techniques. The performance of bonded SRIM hoods was measured by way of stiffness and torsional rigidity tests. The physical and mechanical properties of test specimens taken from SRIM hood parts were measured. An approach for recycling SRIM hoods was proposed. In addition to achieving high surface quality, the goal of this development effort was to produce lightweight, cost-competitive Class-A SRIM parts.

SRIM (structural reaction injection molding) has been restricted to non-appearance parts because of problems with glass “read-out” and surface porosity. Development work undertaken by Miles Inc. has focused on improving SRIM surface quality by means of tooling, reinforcement, and processing. An SMC (sheet-molding compound) Fiero hood outer tool has been modified for use with our SRIM center-gated injection process. The surface quality of SRIM Fiero hoods painted with a glossy black polyurethane coating has been characterized in terms of distinctness of image (DOI), long-term distortion, and short-term waviness. In addition to achieving high surface quality, we have been able to produce lightweight, cost- and performance-competitive Class-A SRIM parts.

Energy absorbing (EA) materials are used in automobile interiors to help protect occupants from injury in the event of front or side collisions. Depending on their function (shoulder or knee bolster) and location within the automobile (instrument panel or door) different energy absorbing characteristics may be required. Polyurethane (PU) foam is ideally suited for these applications because of its chemical and design versatility and excellent energy absorbing properties. Routine measurements to characterize EA materials are often performed at relatively low velocity. Collisions which have a high probability of causing occupant injury, however, usually occur at much higher velocities. Because energy managing properties of EA materials can exhibit a dependence on velocity, testing at velocities similar to actual impact velocities is highly desired to accurately characterize a material's performance.

Two-component, flexible polyurethane coatings are used as protective and aesthetic coatings for many automotive plastic applications. Adjusting the coating flexibility to match the flexibility of the plastic allows the coated plastic to retain the impact resistance of the uncoated plastic. New developments in polyurethane chemistry allow the formulation of coatings with much lower VOC's than conventional flexible polyurethanes. These low VOC, flexible, polyurethane coatings exhibit improved room temperature polishability. This technology also shows the potential to yield coatings with improved environmental etch resistance.

In the highly competitive area of automotive fascias, Miles has already launched a comprehensive program which will assure that Polyurethane RIM elastomers remain the material of choice. Building upon the design advantages of PU-RIM, Miles is working on several programs to reduce the molded fascia costs by developing novel chemistry, unique RIM-systems and enhanced productivity. In recent years it is established that Polyurethane RIM systems offer a full range of physical properties for a variety of performance requirements for fascias, body panels and body side moldings. Miles has developed systems which meet the existing requirements on a much more competitive basis. This paper will talk about the novel low density filler package in the Bayflex 110 system, the experimental Bayflex 95 fascia system, and the experimental Bayflex 180 high performance material as well as discussing design options and achievable productivity enhancements.

Reaction Injection Molded (RIM) Polyurethanes are well-suited to automotive fascia applications. Their excellent impact resistance, paintability, and styling capabilities are well known. Efforts are underway in the automotive industry to improve the production economics associated with manufacturing RIM fascias. One method of reducing fascia material costs is to reduce the density of the polymer. This paper describes new experimental RIM systems that can be molded at a reduced density, yet still pass current OEM requirements, including on-car impact tests. These experimental RIM systems combine new filler technology and new resin formulations. The material cost for this system is competitive (based on molded part cost) with all other current methods of manufacturing fascias.