Low modulus and high elongation seal silicone-Hong...

Low modulus, high elongation seal silicone is specifically adapted to the modern construction industry special silica gel. Because of its excellent resistance to high and low temperature performance, in the range of -50~2500C to maintain low temperature flexibility and high temperature heat-resistant, silicone has been widely used in various types of building envelope and a caulking adhesive sealing material. According to the stress strain behavior of silicone sealants, divided into high, medium and low modulus type. The low modulus type with high flexibility, excellent adhesion and under the low stress and high elongation characteristics, especially suitable for high-rise buildings, large concrete facilities joint special engineering requirements, such as large displacement expansion joint filleting etc.. This kind of sealing material with dynamic bonding and sealing effect, under large deformation conditions, not only can keep on the bonding and sealing performance, but also has the weather resistant, aging resistant, medium and temperature range is wide wait for a characteristic.   Realization of low modulus method   Modulus, high elongation is generally required to satisfy the tensile stress at 100% <0. 4M Pa, elongation at break of > 800, shore A hardness < 20 ( dumbbell like ). According to the rubber elasticity theory, effect of rubber elastic stress strain characteristics of the main factors include: filler reinforcing effect, elastomer crosslinked network perfect degree, cross-linking density and its distribution, plasticizing effect.   Large molecular weight, adding filler of polysiloxane and use of plasticizers and other methods, can reduce the modulus, improved elongation, but can lead to problems such as difficulties in construction, low tensile strength as well as for natural stone and other pollution etc.. Low modulus is mainly by changing the network topology, control of cross-linking density degree and distribution to achieve. For the expansion of low modulus silicone sealant use, may pass on the basis of room temperature vulcanized silicone rubber polymer structure modification and the use of different additives, which can meet with the requirements of different sealing materials, especially for silicone polymers and other materials are modified, so that the sealing materials more perfect performance.