What is the difference between solid silica gel with liquid silicone?
Common silicone shell is divided into solid silica gel and liquid silicone, do you know the difference between the solid silica gel and liquid silicone?
Solid silicone industry based on sodium silicate (sodium silicate) as raw material, hydrolysis produce gel in the acid medium, and then made from silica gel by aging, washing, drying process, according to the water content is different, for the translucent or white solid. Goods sold are irregular granular, globular, micro spherical silica gel, which has good wear resistance, used as the catalyst carrier in fluidized bed operation.
When used as catalyst carrier, is usually the silicone impregnated in solution containing catalytic active component, make the solution absorption in silica gel inside the pore, drying, activation and other procedures, the active component in the silicone surface. Made of silica gel pore structure on the nature of the load type catalyst has important influence, such as pore volume, pore size distribution of silica gel, etc. Traditionally, the average pore diameter is less than 15 ~ 20 a silica gel, said fine silica; The average pore diameter greater than 40 ~ 50 a, called the coarse silica gel. Fine pore structure of the silica gel with high specific surface area, which is beneficial to catalytic dispersion of active components. But fine pore structure is not conducive to the spread of the reactant molecules, reach hidden deep in the depths of the pore of the catalytic active component, thus will reduce the catalyst utilization rate of the inner surface, and deep in the pores generated by the product molecules escape hole, not easily also easy to cause deep side effects. Silica gel on the pore structure and manufacturing method and condition, such as gelling, aging, washing of pH, temperature, time, etc. By reaming process will be commercially available silicone reaming, common method is to place it in the hot kettle of water or add salt aqueous solution (such as sodium carbonate, sodium acetate) extrusion processing, for example: at 320 ℃, 10 mpa hot-pressing process can make the surface and average pore diameter than 135 m2 / g and 123 a respectively of silica gel to 26.9 m2 / g and 508 a.
In addition to the solid silica gel, silica sol liquid silicon sol is important carrier of the material, industry usually by ion exchange method makes the silica sol sodium silicate sodium off system. It is translucent milky liquid, the content of silica in the sold goods is commonly 20% ~ 30%, and the most high is 50%, the colloidal particles diameter of 100 ~ 200 a, some items of 1300 a. A high concentration of silica sol is usually with the aid of trace amounts of sodium oxide to maintain its stability. Colloidal silica drying after into porous solids. For example, in production by oxidation of propylene ammoniation of acrylonitrile (oxygen) phosphorus molybdenum - bi - / silicon oxide catalyst, is to contain active component solution mixed with silica sol, the spray drying method into micro spherical catalyst.
Organic silicon rubber by linear polysiloxane with reinforcing filler, under the condition of heating pressure sulfide generated special synthetic elastomer. It perfectly balanced mechanical properties and chemical properties, and thus can satisfy the requirement of many demanding applications today.
High performance of silicone rubber in the following areas:
1, high and low temperature stability
2, the inert (and tasteless, odourless)
3, transparent, easy to color
4, wide range of hardness, 10-80 Shao Er hardness
5, resistant to chemicals used in
6, weather resistance,
7, the sealing performance
8 and electrical properties
9, resistant to compression deformation
In addition to the outstanding performance, compared with conventional organic elastomer, silicone rubber are particularly easy to manufacture. Silicone rubber easy flow, thus it can be in mold under the condition of low energy consumption, calendering, extrusion. Easy processing means high production efficiency.
Silicone rubber can provide the following form:
Mixing adhesive: this ready-to-use materials can be according to your color and catalytic processing equipment and end use.
Base material: this kind of silicone polymer also contains reinforcing filler. Rubber base material can be further and pigments and additives mixed, mixed gel formation, meet your color and other manufacturing requirements.
Liquid silicone: this two-component liquid rubber system can enter the appropriate pump injection molding equipment, and then the thermal curing into molded rubber parts.
Fluorine and silicone rubber mixing glue and base material: fluorine and silicone rubber keep many of the key properties of organic silicon, in addition, it also has excellent resistance to chemicals, fuel and oil resistance.
Liquid, raw material costs and the cost of production, is a solid-state high. To make the finished product, basically is not easy to distinguish.