Silicone rubber what classification how do I select the _ _ raw rubber vulcanizing agent type all have
Silicone rubber what types according to the different characteristics such as high temperature wear resistance of these features, silicone rubber press vulcanization mechanism how to classify, raw rubber, how to choose types of vulcanizing agent what are, take you get to know the common knowledge of the industry.
Silicone rubber feature classification 1.
Universal: using vinyl silicone rubber and reinforcing agent etc, vulcanizing machine belongs to moderate intensity physical and mechanical properties, tensile strength 4.
9 to 6.
, elongation is: 200 ~ 300%, the dosage, the most common one of the largest class of rubber.
High strength type (
High resistance to tear)
: using vinyl silicone rubber or low phenyl silicone rubber, with high specific surface area of the gas phase silica or after modification of silica as reinforcing agent, and adding suitable processing aid and special additives, etc comprehensive improvement measures, improve the crosslinking structure (
Produce concentrated crosslinking)
, improve the tear strength, the tensile strength of the rubber for 7.
8 ~ 9.
80 ~ 100年kgl / cm2)
, the breaking elongation is 500% ~ 1000%, tear strength, 29.
4 ~ 49 kn / m。
High temperature resistant type: the vinyl silicone rubber or low phenyl silicone rubber, the type of reinforcing agent and heat-resistant additives by the appropriate choice, can be made of 300 ~ 350 ℃ high temperature silicone rubber.
Low temperature type: mainly adopts low phenyl silicone rubber, brittleness temperature can reach -
120 ℃, in -
90 ℃ without loss of elasticity.
Low compression permanent deformation type: the vinyl silicone rubber, vinyl to dedicated organic peroxide vulcanizing agent.
When the compression ratio is 30%, the compression under 150 ℃ for 24 ~ 72 hours after compression permanent deformation at 7.
0 ~ 15% (
Ordinary silicon rubber is 20 ~ 30%)
Wire, cable type: mainly adopts vinyl silicone rubber, selection of electrical insulation good gas phase silica as reinforcing agent, has the good delivery performance.
Resistance to oil solvent: mainly adopts ammonia silicone rubber, generally adopts the general type and high strength type two kinds.
Flame retardant 9.
Conductive type 10.
Heat shrinkable type.
Avoid secondary sulfide type: the vinyl content is higher of vinyl silicone rubber, raw rubber and compound control through the PH value, adding special additives.
The rubber industry manual P544)
Silicone rubber sponge: in a vinyl silicone rubber of join nitroso compounds, diazonium and azo organic foaming agent, can be made of sponge holes evenly.
Silicone rubber press vulcanization mechanism can be divided into three types of silicone rubber press vulcanization mechanism can be divided into three categories: organic peroxide caused by free radical crosslinking type, condensation reaction, addition reaction.
Compound mainly includes: reinforcing agent, vulcanizing agent and some special additives, general needs 5 ~ 6 components can be composed of practical formula.
The formula design note: 1.
The raw rubber, silicone rubber is high saturation are usually not sulphur vulcanization, adopt heat curing, heat curing by organic peroxide as curing agent, therefore, must not be found in the raw rubber can with peroxide decomposition product of active substance (
Such as tank some organic carbon black, promoting agent and stabilizer, etc. )
, otherwise, it will affect sulfide.
Silica gel products generally used at high temperature, the compound should be stable at high temperatures, therefore usually do choose inorganic oxide reinforcing agent.
Silicone rubber in trace amounts of acid and alkali under the action of polarity chemical reagents such as easy to cause the cracking and rearrangement of siloxane, results in the decrease of silicone rubber heat resistance.
So it must be taken into account when choosing chelating agent of acid and alkali, also should consider the acid and alkaline peroxide decomposition products, so as not to affect the performance of the vulcanizates.
Silicone rubber for nonpolar rubber)
The choice of raw rubber, raw rubber of choice: on the basis of product performance and the conditions of use of choice with different properties of raw rubber.
Vinyl silicone rubber: products requires the use of temperature in -
Within the scope of 70 ~ 250 ℃, can adopt vinyl silicone rubber.
Low phenyl silicone rubber: products requires the use of high - temperature
Within the scope of 90 ~ 300 ℃, can use low phenyl silicone rubber.
Fluorine silicone: products require high and low temperature fuel oil resistant and solvent resistance, using fluorine silicone curing agent type hot vulcanized silicone rubber vulcanizing agent: there are mainly organic peroxide, aliphatic azo compound, inorganic compound, high-energy rays, etc.
Commonly used organic peroxides.
Beautiful morning has double m and double minimum)
Reason: organic peroxide is stable at room temperature, but quickly decomposes at high temperatures can produce free radicals, so that the silicone rubber crosslinking.
Silicone rubber vulcanizing agent commonly used: BP, DCBP, TBPB, DTPB, DCP, DBPMH.
Above is about the classification of silicone rubber, raw rubber, how to choose vulcanizing agent types of related to arrange, hope everyone to classification of silicone rubber, raw rubber selection of vulcanizing agent types have a deeper understanding of, choose the silicone products factory in foshan, guangdong area preferred rubber plant 10 old factory professional and more efficient.