Rubber seals are used in many industrial, commercial and consumer settings. Many kinds of manufacturing equipment require use of rubber seals, especially in manufacturing processes that involve pressurized liquids or gasses.
Machinery that is sensitive to dust accumulation or environmental conditions may also be shielded by some variety of rubber sealant.
Rubber seals are an essential component in aerospace and marine applications in which atmospheric stabilization is necessary. In consumer contexts, rubber seals can be found in garden hoses, swimming pool pump systems, kitchens, bathrooms, as insulation and weatherstripping and in many other applications.
A rubber seal can be a gel, film, putty or strip and will adhere to glass, ceramics, concrete, paper, bricks, other molded rubber materials, textiles, leather, metal, wood, plastic and many composite materials and porous surfaces.
Rubber is an elastometer and can be created from harvesting and processing natural latex; it can also be produced synthetically by processing certain hydrocarbons. Both natural and synthetic rubber must undergo a series of shaping and treatment processes in order to become useful rubber seals.
There are several processes by which rubber can be shaped and strengthened. Rubber seals can be extruded, injection molded or subject to other thermoforming (heat forming) processes, though extrusion and injection molding are the most common methods.
Extrusion involves forcing molten rubber through a die, which is a specially shaped hole in a metal plate. When molten rubber is forced through a die, it takes the shape of the die; this method is used to create long profiles, strips and channels.
In the context of rubber seals, extrusion is used primarily to create long, thin seals for moisture control purposes. Examples of extruded rubber seals include weatherstripping and rubber trim. Injection molding can produce more complex and specialized rubber seals. The injection molding process involves forcing molten rubber into a mold cavity that is shaped like the desired seal.
The rubber fills the mold and takes its shape, and upon emerging it cools, hardens and becomes a finished rubber seal. Non-extruded rubber sealants are used in contexts when a seal needs to fit into, around or between surfaces. Such sealants often are intended to be applied by end-users as liquids or gels that harden after a short time.
Examples of applications for these varieties of sealant include caulking and waterproofing materials.