1. How can single component organic silicone products achieve optimal curing performance?
Single component condensation cured silicone rubber products are cured using moisture in the air. During curing, from the surface to the inside, condensation cured silicone rubber can cure for 3 mm within 24 hours under conditions of 25 ℃ and 50% RH; It takes 7 days to achieve the inherent physical properties.
2. Why is there a difference in surface drying time between winter and summer?
The surface drying and curing speed of single component condensation cured silicone rubber products are closely related to environmental temperature. In winter, when humidity and temperature are low, the surface drying and curing speed of the adhesive is slow, while in summer, when humidity and temperature are high, the surface drying and curing speed of the adhesive is fast.
3. Why is there a difference in viscosity between winter and summer?
The viscosity of the adhesive will vary with temperature, with a decrease in viscosity during high temperatures in summer and the opposite in winter, but it will be within the acceptable range.
4. How to improve the curing speed?
When the curing thickness is greater than 6mm, it is recommended to use two rounds of adhesive pouring; Increasing temperature and humidity can accelerate the curing speed of the product, but the temperature should not exceed 50 ℃. Increasing humidity has a better effect than increasing temperature.
5. Why is white silicone prone to yellowing?
The ketone oxime cross-linking agent, amino silane type tackifier, and catalyst contained in the ketone oxime type silica gel may undergo surface yellowing due to the oxidation of amino groups or some chemical reactions of the catalyst under long-term ultraviolet light irradiation or high temperature environments above 80 ℃. To improve the yellowing phenomenon, special formulas are required, such as solar silicone, which has good resistance to yellowing. In the absence of complete solidification of dealcoholized silica gel, the titanate catalyst that did not participate in the reaction will display its yellow color under heating conditions, causing the colloid to turn yellow.
6. How is the temperature resistance of silicone?
The general temperature range of silicone is -40 ℃ -200 ℃, and the long-term use temperature does not exceed 150 ℃. Special high-temperature resistant adhesives such as iron red silicone have a temperature range of -40 ℃ -250 ℃, and the long-term use temperature does not exceed 180 ℃. Temperature resistance is closely related to whether the colloid has fully cured, and heating before it is fully cured can cause adverse phenomena such as bubbles, cracking, and smoking.
7. How does the "mist" phenomenon of ketone oxime type silica gel occur in a closed system?
When ketone oxime silica gel is used in closed systems, such as lighting, car lights, and other industries, it sometimes produces a phenomenon similar to "mist" on the inner surface of glass, which greatly reduces the transparency of glass and affects its transparency and aesthetics. This is due to the inability of ketone oxime released during the curing of deioxime type silica gel in a closed system to be released into the atmosphere in a timely manner and to aggregate and adhere to the surface of the glass; The use of dealcoholized silica gel can easily avoid such aerosol phenomena, as the products released during solidification are alcohols, which are gases at room temperature and do not aggregate and adhere to the glass surface.
8. How to remove silicone?
Before the silica gel is solidified: scrape off the uncured paste with a putty knife, and then clean the residue with Petroleum ether (kerosene). After silicone curing: First, mechanically scrape off as much silicone as possible with a knife or razor, and then use a solvent (kerosene or acetone) to remove various oil residue or silicone. Soak the silicone overnight in this solvent and let it swell before cleaning.
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