Silicone to improve composite manufacturing
Composites were first developed over 70 years ago for use in aeronautics and later for aerospace. This revolutionary material enabled designers and engineers to craft complex and very resistant low-weight parts that could be molded in a great variety of shapes. For many years now, composites have gradually entered into our everyday lives and are today used by a wide range of manufacturers that serve consumers and industrial markets, including:
- Aeronautics and aerospace for civil and military applications
- Automotive and transport for rail, road vehicles (including sports cars) and farm equipment
- Marine applications for pleasure crafts, cruise ships and naval vessels
- Construction and civil engineering, for building and decorating homes, offices, commercial properties and for roadwork
- Chemical and industrial applications, in particular for equipment such as tanks, reservoirs and other corrosion resistant and harsh-weather applications
- Renewable energy systems, including wind and sea power turbine parts
- Oil & Gas, for pumps, valves and other critical parts
- Electronics and electrical equipment
- Household goods and equipment, including domestic appliances and HVAC
- Consumer products, from sports equipment to protective gear.
These various parts are composed by different kinds of resins, reinforced fibers and other hybrid products. One of the traditional production methods uses disposable plastic bagging sheets that are manually placed and assembled by highly skilled operators. This process is often quite expensive, time consuming and generates large amounts of waste since every mold requires a change of bagging.
A more recent alternative is to shape these products with infusion molding techniques using reusable vacuum bag (RVB) membranes made of silicones. These are more cost-effective (in particular for larger batches) and more productive than traditional bagging techniques. This technique also improves the quality and repeatability of parts produced and is also cleaner and more respectful of the environment because of reduced use of consumables.
Silicones are also used for the production of pressure pieces, which are blocks or wedges that allow to apply pressure on the composite during the composite process. Pressure pieces are particularly useful for shaping sharp edges, where it is difficult to maintain the stability of the composite complex and its fabric reinforcements. Silicone pressure pieces offer the advantage of anti-adhesion and good chemical resistance, even to aggressive resins and can be reused several times.
Silicone release coatings bring the same properties when used as coatings on interleaving sheets for "pre-preg" which is where composite fibers are "pre-impregnated" with a thermoset polymer matrix material, such as epoxy. In the final process, a layer of paper coated with silicone is used to protect the composite material from the heated presses and release the final "hard set" item.
Other applications in the composite field exist for silicones and we are convinced that there are plenty of applications to create when combining the dynamics of the composite market with the excellent properties of silicones. We invite you to get in touch with us to talk about your specific requirements or to tell us about any possible issues you may be having in molding composites. At Elkem Silicones we offer you customized services and solutions to meet your specific needs. Our team of experts will do their very best to propose services and solutions to improve your processes.