The volume properties of the flow resistance of liquids, quasi-liquids, or quasi-solids, that is, internal friction or internal resistance between molecules as they flow in response to external forces.Usually the viscosity is proportional to the hardness.
The ability of a material to resist partial pressure of hard objects into its surface is called hardness.Silicone rubber has a range of 10 to 80 shaoshi hardness, which gives the designer full freedom to choose the required hardness to achieve the best specific function.Various intermediate hardness values can be achieved by mixing the polymer substrate, filler and auxiliaries in different proportions.Similarly, the time and temperature of heating and curing can also change the hardness without damaging other physical features.
Tensile strength is the amount of force required per unit of range to cause a rubber sample to tear.The tensile strength range of hot-desulfurized SSR is between 4.0 and 12.5MPa.The tensile strength range of fluorosilicone rubber is between 8.7 and 12.1MPa.The tensile strength of liquid silicone rubber ranges from 3.6 to 11.0MPa.
Resistance to incision or nicking when applying force on a sample with an incision.Even when cut and placed under extremely high torsional stress, hot desulfurized SSR is not torn.The tear strength range of hot-desulfurized SSR is between 9 and 55 kN/m.The tear strength range of fluorosilicone rubber is between 17.5-46.4kn /m.The tear strength of liquid silicone rubber ranges between 11.5 and 52 kN/m.
Usually refers to "ultimate rupture elongation" or the percentage increase relative to the original length of the sample when it breaks.The typical elongation of hot - sulphur solid silicone rubber ranges from 90 to 112 %.The general elongation of fluorosilicone rubber is between 159 and 699%.The typical elongation of liquid silicone rubber is between 220 and 900%.Different processing methods and hardener selection can greatly change the elongation.The elongation of silicon rubber is closely related to temperature.
6. Operation time.
The operation time starts from the moment the colloid is added to the vulcanizing agent.This operation time and the later curing time are not completely separated. The gel has been curing reaction since the moment the curing agent is added. This operation time means that the curing reaction of the product for 30 minutes will not affect the quality of the finished product.Therefore, the more time saved in the process of product operation, the more favorable to the finished product.
Some say cure time.That means that after this long period of time the vulcanization of silicone is basically over.This is basically the end of the product which means that the product is available, but in fact there is a very small amount of the curing reaction that is not finished.So products made with silicone rubber, such as molds, often need to be put up for a while before they are put into use.