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Lightweight reinforced RIM polyurethane substrates are increasingly being specified for fully covered automotive applications such as interior door panels, instrument panels, and package shelves. In addition to offering a 30-40 % weight reduction over conventionally used substrate materials, consolidation in manufacturing steps are achieved by molding direct to polyvinylchloride (PVC), polyurethane (PU) and/or textile coverings. Weight reduction and consolidation of manufacturing steps lead to considerable part cost savings. Styling trends toward complex, deep drawn door panels, integrated with instrument panel modules, are easily fulfilled with low pressure RIM. Existing RIM capital used to produce RRIM fascia, cladding, and body panels is suitable to manufacture low density RRIM substrates (LD-RRIM).

An innovative and economical new method has been developed to fabricate glass fiber preforms in the Structural Reaction Injection Molding (SRIM) process to produce structural composite components. The method involves blowing a resin powder through a ring of flame in a commercial thermal spray gun to achieve a melt, and directing the melt onto a fiber reinforcement where the polymer solidifies on contact and binds the fibers together. The fibers are fed through a chopper gun and cocurrently deposited with the binder onto a screen in the shape of the part. A vacuum is applied to the back of the screen by a blower to hold the fibers in place. The thermal spray process has significant economical advantages over the use of mat to fabricate preforms due to lower raw material costs and waste. It also has many advantages over traditional directed fiber processes, including capital and energy savings from the elimination of the preform drying operation.

The advantage of internal mold release in the production of automotive parts such as exterior fascia and body panels is well known. Recently a new type of internal mold release technology has emerged in the area of low density RIM for interior door panels. Products have been developed for both low density reinforced RIM and structural RIM applications without sacrificing physical properties. This latest technology has the potential for producing hundreds of parts after a single application of external mold release. The exact number of parts that can be obtained will vary depending on several factors including the initial condition and design of the mold. Although able to release from aluminum or steel, adhesion to vinyl cover stock is not greatly affected. Therefore, these products can be used for both pour behind vinyl and substrate only applications.

A new plastic and processing technology known as ISP (Instant Set Polymer) has been developed that allows production of essentially any size part via liquid injection molding. Mold cycle (60 sec) is independent of part area or thickness (1/4″ to 6″). Items 12 inches thick and weighing 200 lbs have been successfully produced.

The commercial success of reaction injection molding (RIM) has led to concepts using RIM machinery to mold high modulus glass reinforced composites. This paper describes the static and dynamic mechanical properties of three different resin systems based on polyisocyanurate and polycarbamate chemistries with the use of a continuous glass mat.