Sponge Profiles and Solid Profiles
Durometer is used to describe both sponge profiles and solid profiles. By fabricating dual durometer rubber into a single part, a seal can have areas with different physical properties. With window seals, for example, the harder rubber attaches to the window frame and the softer rubber faces the glass window.
Solid profiles are harder than sponge profiles and, therefore, most resistant to compression. Most solid profiles range from under 30 duro to over 120 duro, depending on their shape. At 40 duro, solid rubber profiles have the consistency of pencil erasers. At 90 duro, they are hard like hockey pucks.
Sponge rubber can also be shaped into various rubber products. Typically, however, sponge profiles are characterized as soft, medium, and firm. By combining sponge and solid rubber into a single component (such as bulb trim seals), different zones of hardness are achieved.
Bulb Trim Seals and Complex Rubber Profiles
Elasto Proxy offers a variety of dual durometer seals for a wide range of applications. Simple, standard bulb trim seals can have a 70 duro retainer and a medium foam bulb. Complicated rubber profiles may require different colors or plastics.
Tooling costs are higher for custom, complex parts; however, a wide range of standard, in-stock dual durometer profiles are available. When choosing standard dual durometer seals, consider product specifications such as materials, applications, dimensions, quantity per box, and quantity per coil.
Seal Materials and Sealing Applications
Standard dual durometer bulb seals are usually made of EPDM or TPE. A type of synthetic rubber, EPDM provides insulation against hot and cold temperatures. Applications include door seals and window seals for building andconstruction products, automotive applications, and mobile specialty vehicles. EPDM is also in green power projects.
Thermoplastic elastomers (TPE) are rubber-like materials that combine the processing strengths of thermoplastics with the best qualities of thermoset rubbers. Thermoplastics are temperature-sensitive plastics that become soft when heated, and then harden when cooled. Thermoset rubbers resume their normal shape after being stretched, twisted, or distorted.