These thermoset materials give a unique combination of moulded properties which are unmatched by any other plastic raw materials in the same price range, making them ideal for a wide range of applications, particularly in the domestic field. Of especial importance is their ability to not soften or melt on heating as thermoplastics do, this being a result of irreversible cross linking of the polymer that takes place during the moulding process (compression or injection) under conditions of heat and pressure.
Urea formaldehyde (UF) materials combine a virtually unlimited range of colours and excellent colour retention with good electrical properties, solvent resistance, high flame retardance, high rigidity, surface hardness and scratch resistance and permanent anti-static properties.
Uses : Electrical components, closures, toilet seats
The melamine formaldehyde (MF) materials give mouldings with a superior surface performance to UF materials. Their excellent stain resistance and low formaldehyde extraction properties make them suitable for food contact applications such as table and kitchenware whilst their greater heat resistance makes them ideal for such items as ashtrays.
Uses : Tableware, Kitchenware, Knobs and components for white goods, electrical accessories
Phenolic (Bakelite) moulding compounds are based on a phenol-formaldehyde resin processed with inert fillers, cross-linking agents, accelerators, and pigments or dyestuffs. They can be readily tailored to suit specific property or mouldability requirements. They are low cost thermosetting materials capable of being moulded under heat and pressure to give flow then permanent setting to a desired form.
Phenolic mouldings have good electrical properties, heat resistance, moisture resistance, dimensional stability, high surface hardness and mechanical strength.
Uses : Electrical components, knobs and components for white goods, meter parts, automotive components, cookware handles and fittings.
Dough (Bulk) Molding Compound (DMC sometimes referred to as Bulk Moulding Compound usually abbreviated to BMC) is a thermoset plastic resin blend of various inert fillers, fiber reinforcement, catalysts, stabilizers, and pigments that form a viscous, putty like, compound for compression or injection molding. DMC is highly filled and reinforced with short fibers. Glass reinforcement represents between 10% and 30%, with glass length typically between 1mm and 12.5mm.
Depending on the end-use application, compounds are formulated to achieve close dimensional control, flame and track resistance, high dielectric strength, corrosion and stain resistance, superior mechanical properties, low shrink, and color stability. Its excellent flow characteristics and electrical and flame resistant properties make DMC well suited to a wide variety of applications requiring precision in detail and dimensions. The material is available in a wide variety of colors, and can tolerate powder-coat or water-based paint.
Uses : Electrical components, white goods components, hifi components, cookware, telecommunication components, lighting components.
Sheet Molding Compound (SMC) is used in compression molding, often of larger parts, where higher mechanical strengths need to be achieved. Glass reinforcement is between 10% and 60%, and glass length is slightly longer than DMC, between 12.5mm and 25mm.
As with DMC, thermoset SMC is a mixture of polymer resin, inert fillers, fiber reinforcement, catalysts, pigments and stabilizers, release agents, and thickeners. Manufacture of SMC is a continuous in-line process. The material is sheathed both top and bottom with a polyethylene or nylon plastic film to prevent auto-adhesion. The paste is spread uniformly onto the bottom film. Chopped glass fibers are randomly deposited onto the paste. The top film is introduced and the sandwich is rolled into a pre-determined thickness. The sheet is allowed to mature for 48 hours.
SMC can be molded into complex shapes. High mechanical properties and excellent surface appearance make SMC ideal for automotive Class ‘A’ body panels, high-strength electrical parts, business equipment cabinets, personal watercraft, and various structural components.
Uses : Automotive components, mass transit components, building and construction components. Lighting components.
R.E. Davison will advise you on the best material for your product.