Method for manufacturing RIM composites

In a method of manufacturing a composite RIM article, by use of a RIM mold with a female body including a cavity therein separated by a divider to divide the cavity into lower and upper air-filled spaces which are filled respectively with a low viscosity RIM mixture and a high viscosity RIM mixture by simultaneously injecting the respective mixtures as separate streams into one or the other of the lower and upper air-filled spaces in an amount to fill such spaces, the improvement comprising:

• preforming the divider from glass fibers to form open pores throughout the divider;
• filling one space receiving the high viscosity material at a rate which prevents it from passing into the pores of the glass fibers;
• and filling the other space at a rate which permits the low viscosity material to penetrate and fill the pores of the glass fibers without passing into the one space to prevent significant amounts of the low viscosity material mixing with the high viscosity material;
• and reacting the RIM materials in the mold to concurrently form a high strength armature in the space receiving the low viscosity material, a foam cover in the other space and a high strength interface boundary therebetween.