Classification of building sealants
1, according to the basic polymer classification
Including: silicone, polyurethane, polysulfide, acrylic, butyl, asphalt and oily resin modified products. One silicone, polysulfide, polyurethane three room temperature curing elastic sealant in China the most widely used, especially silicone sealant products.
Silicone sealant because of its special molecular structure, its molecular structure both inorganic and organic polymer characteristics. The raw rubber of the silicone gum is a polymer composed of Si-O as the main chain. Its bond can be 106Kcal / mol, while the usual polymer materials CO and CC bond energy are small, respectively, 80 and 85.2cal / mol, in other words, if the interruption of Si-O chemical bond, the inevitable need for higher energy, So the silicone rubber stability, with superior anti-UV, ozone resistance, weather resistance, temperature and single component, two-component application of various forms of characteristics, and can be based on the needs of the building to create different performance requirements of the product , Especially in the construction of hidden frame glass curtain wall structure is irreplaceable in other materials. And China's silicone sealant production of raw materials industry relative to the development of polysulfide, polyurethane scale and mature, the current silicone sealant products accounted for more than 60% of China's construction sealant use. Foreign modified silicone products in the construction of the application is also more current China is limited to other areas.
Construction of polysulfide sealant as early as the 20th century, 60 years used in the field of aircraft, aviation and other oil-resistant, solvent-resistant adhesive seal in the 80's in China is also used in the construction of the seal, due to raw material production costs High, has been basically replaced by silicone products. However, the polysulfide sealant has good anti-breathability and oil resistance and solvent resistance. It is still widely used in the manufacture of hollow glass, partly for the construction of seawater, garbage dump, oil storage structure and steel structure anticorrosive seal.
Polyurethane molecular structure of the diversity, you can create a wide range of different modulus products for a lot of material bonding. And because of its flexible molecular chain, its resistance to vibration and fatigue performance is very good, especially for different materials, bonding and bonding of flexible materials, and there are very excellent low temperature performance, in many industries Very wide. In the field of construction of the material in the United States, Japan, Germany and other developed countries close to the application of silicone products, in China due to the backwardness of raw materials industry, the development of sealant products subject to certain constraints. There are also less flexible elastomer products that include butyl, acrylic, asphalt and oily resins. The elasticity of such products is small, can be applied to the construction joints of mechanical parts of the low displacement requirements.
2, according to the ability to sort the classification of the performance of the seal products used to determine the main sealant based on the standard.
Whether it is the international standard ISO11600 or the United States ASTMC920, Japan's JISA5758, the British BS5889, Germany DIN18540,18545 standards are based on the product's anti-displacement ability to grade. China's current new building sealant product standards are in accordance with ISO11600-2000 "architectural sealant classification and requirements" to develop. According to the test of the cold stretch / hot compression range can be divided into the following levels: 25LM level, 25IM level, 20LM level, 20HM level, 12.5, 12.5E level, 12.5P level, 7.5P level. ISO11600-2000 standard grading performance indicators in Table 1-3:
JC / T881-2001 Sealant for concrete construction joint: YJC / T882-2001 Sealant for joint of glass curtain wall, JC / T883-2001 Sealant for stone building glue
3, single-channel sealing seepage increased by 16 times the estimated life of 4 years bending angle group box insulating glass
No angle infiltration
No connectors required
It is stabilized by a hot melt sealant containing a desiccant
Double-channel sealed moisture permeability calculation life of 85 years