IOTA CORPORATION LTD.
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Because of its both silicone sealant and polyurethane sealant advantages and strengths, shows excellent weatherability, durability, high ability to resist deformation displacement, good bonding, coating, environmental friendly, low polluted, and the advantages of low viscosity and excellent operation, has been more and more get the attention of the domestic construction industry, and in the industrial fields such as automotive manufacturing, rail transportation, container manufacturing, equipment manufacturing, electrical and electronic fields also being used more and more promotion.
The structural characteristics of silane modified polyether are that the main chain is macromolecular polyether and the end group is silane alkyl containing hydrolyzable groups. The synthesis of silane - modified polyethers is usually accomplished by two - step method.
Step 1: allyl polyether alcohol and hydroxyl polyether were used as raw materials, dihalomethane (H2CX2) was used as chain extender, and alkaloid was used as catalyst to prepare allyl terminated polyether intermediate through chain extension reaction.
Step 2: in the presence of platinum catalyst, silane modified polyether was prepared by the reaction of the refined intermediate with methyl dimethoxy silane through terminal silylation reaction.
The curing mechanism of MS sealant is wet curing. In the presence of room temperature, moisture and appropriate catalysts (amine, tin, etc.), the alkoxy groups in the end alkoxy groups are firstly hydrolyzed into si-oh groups. Then, si-oh groups or si-oh and si-0ch condense, release water or methanol, and form Si-0 -Si bond. Finally, the crosslinking is a physical structure elastomer with Si - 0 - Si bond as the network crosslinking point and flexible polyether chain between the crosslinking points.
