The main material of the sealing gasket is rubber. It is required to have excellent resistance to sun-light ultraviolet aging, ozone aging and thermal oxygen aging, low compression set and creep, high and low temperature and rain-proof water, etc. In the process, the compound should also have the characteristics of easy extrusion, small shrinkage deformation, good flexibility and so on. EPDM rubber with high filling strength and multi-element physical-chemical anti-aging system has become the preferred sealant.
Basic characteristics and requirements of rubber gasket
1) The rubber gasket is a typical rubber extrusion product. In addition to the special requirements for the extrusion flow characteristics of the material, due to the external exposure and atmospheric contact, high attention must be paid to the aging resistance of the product to achieve the goal of the same service life, generally more than 20 years.
2) The shape of the rubber gasket is complicated and varied, and the changing speed is fast. Therefore, the mouth design becomes the most critical technology, which is related to the precision and speed of extrusion. CAD/CAM must be used as the technical means to ensure the dimensional tolerance of the product.
3) The gaskets are mostly composite products of rubber, plastic, metal and fiber, including solid, sponge and hollow. The surface is often coated, sprayed, chemically modified and electrostatic flocking. Therefore, the adhesion between composite material layers is a non-negligible condition, which determines the appearance quality and service durability of sealant strips.
4) In addition to the special performance requirements, the material cost has the largest impact on the production and sales, accounting for 70%~80%, which has become the main link of enterprise profit and market competition, and light weight is the guiding ideology of production and the expected requirements of use.
5) The rubber gasket requires a variety of matching and high vulcanization technology. It not only has the adjustment of different hardness of solid rubber, the matching of hard rubber, but also the control of foam size, especially the firm adhesion between them. In addition, there are TPE, PVC and other thermoplastic elastomers and plastics preparation methods.
6) The rubber gasket is not only sealing material, but also damping and buffering material. For the exposed sealing rubber gasket and decoration material, most of them have three functions, which are not only air-tight water sealing, but also noise reduction, sound insulation, comfort and beauty. No peculiar smell and pollution are allowed. Color change, frost spraying, corrosion and rusting are not allowed.
7) The rubber gasket shall be environmentally friendly. Besides energy saving in production, it shall also be flame retardant in use.
8) There are both traditional products and high-tech products , which have big differences. The rubber gasket shall meet the fine size accuracy and there shall be no defects such as exposed and elongated glass fibre thread.
9) The special property of rubber gasket is very strong , almost one specification for one kind of window or door , which is closely combined with the window or door to form a group of assembly parts and become a part of the whole window seal, which is fully matched with each other. It is required to design and assemble the door and window system synchronously, It is required to design and assemble synchronously with the door and window system to realize the cycle integration from the cooperation of profile, hardware, rubber gasket, glass and insulation strip to the simulation production and the whole window effect.
10) The rubber gasket shall be easy to install and disassemble, resistant to glass and metal scratches, and the relevant contact parts will not be deformed and damaged after being disassembled for many times. For the active gasket, it should be flexible, light and nimble, and not easy to pinch people's fingers.