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High-temperature resistant silicone mold
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Frequently Asked Questions
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The durability of casting for a condensed two-component RTV silicone rubber model is affected not only by the mechanical strength of the silicone rubber, but also by the degree of structuring of the model surface, the type of casting material, and the number of castings per day. These physical and chemical influences cause the demolding properties to gradually disappear, and eventually the casting and model surface damage cannot be used continuously.
In the case of unsaturated polyester casting, the styrene contained in this olefin resin easily penetrates the interface of the silicone rubber model during the curing process inside the silicone rubber model, and polymerizes inside the silicone rubber, forming an interpenetrating network structure of silicone rubber and polystyrene on the surface of the model. As the concentration of polystyrene on the surface of the model increases, the demolding property gradually decreases, and a white hard shell is formed. This damage is usually called "burning the mold." The surface of the burned mold is easily attached to the casting resin, and the model surface is damaged during demolding, losing its usability.
In the case of polyurethane casting resin, the isocyanate component will also chemically attack the surface of the silicone rubber model. That is, the Si---OH group formed by the hydrolysis of the excess crosslinking agent in the silicone rubber reacts with the isocyanate to form a copolymer, which, like unsaturated polyester, causes mold burning, causing the demolding property to gradually decrease and eventually lose its practicality.
To suppress this mold burning phenomenon, there have been schemes such as applying a release agent to the surface of the silicone rubber model and adding an internal release agent to the base material. There are also solutions from the silicone rubber itself formulation, such as the polymer/crosslinking agent content, filler type and amount, and catalyst type and amount, but they all have shortcomings such as insufficient forming accuracy, complex process, and inconspicuous anti-burning mold. A more effective method is to add an anti-burning agent to the base material or curing agent.
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Contact Us
Tel: 89948454 / 83212351
Fax: 0086-755-89948030
Q Q: 2355542596
Email: hyd@szrl.net
Address: building a, No. 3, Hongling 1st Road, Liulian Shibi Industrial Zone, Pingdi Town, Longgang District, Shenzhen
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