| Tech Tips |
 |
 |
Silicone Glove MoldingThe low-pressure rotocasting process today is seeing a resurgence in popularity fostered, in part, by the development of improved process controls and easier-to-handle plastics. Moldmaking methods have improved as well. Specifically, the combination of high-quality silicone rubbers with rigid polyurethane systems is yielding glove molds that facilitate both casting and demolding of one-piece hollow parts with severe undercuts, fine surface detail and/or threads and handles. Effects of Oxidation on Amine-Containing PolyurethanesAmong the highest performing elastomers in the Innovative Polymers product line are polyurea/polyurethane hybrid systems that exhibit excellent durability with high strength, high heat resistance and good elongation. Specific product lines formulated using amine curatives include the IE-644 and IE-9000 families of Shore A hardness polyurethanes, the high-performance TP-4000 polyurethanes series and the VA-1000 Shore A hardness polyurethane systems for vacuum assisted casting. UL 94 Test Standards for PlasticsOne of the key criteria in determining the suitability of plastics, such as Innovative Polymers’ polyurethanes, for building appliances, electronics and under-the-hood vehicle components is the Underwriters' Laboratories (UL) flammability rating of the materials. UL has assigned 12 different flame classifications to materials based on the results of lab-scale flame tests. Moisture ContaminationPolyurethanes are moisture sensitive materials. Polymers that are exposed to moisture may form an in-dissolvable skin on the resin surface. Calculating ShrinkageBefore casting a polyurethane part, an accurate assessment of shrinkage is a key to obtaining dimensionally accurate results. Shrink in polyurethane systems, and other thermoset plastics, is affected by several factors. Air BubblesTrapped air in a mixed polyurethane resin system can produce bubbles in the surface or wall of a cast part. To prevent the formation of voids, care must be taken during the mixing process. Soft Spots / Incomplete CureThe most common cause of incomplete curing is the use of inaccurate resin to hardener ratios and inadequate mixing of system components.
Coloring Innovative Polymers Products
Innovative Polymers provides a color-matching service for customers who purchase our polyurethanes. However, before considering polyurethane pigmentation, there are many factors to consider. Painting Cured Polyurethane PartsMany modelmakers, prototypers and molders of polyurethane parts must paint cured plastic surfaces to attain a production-quality finish. Some customers avoid painting by color-matching the selected polyurethane to the desired shade. Innovative Polymers specializes in color matching our materials to virtually any Pantone color. However, for projects that require painted surfaces, the following procedures can help ensure high-quality results. |