Basic overview of high temperature sealants
High temperature sealant, as the name suggests, is used for bonding and sealing protection in the environment under high temperature conditions. It is a one-component silicone paste sealant, industrial use, high-quality sealing compound, suitable for smooth and flat sealing surface ( Butt joints) with high temperature and pressure conditions.
Silicone high temperature sealant is a high temperature sealing adhesive made of organic silica gel as the main body, defoamer, leveling agent, curing agent and other polymer materials.
The limit of high temperature resistance of sealant
- High temperature resistant sealant is a high temperature resistant silicone sealant, which can be continuously maintained at -65°C without affecting performance. It can withstand high temperature intermittently, has long-lasting elasticity, good high temperature sealing function and high electrical insulation function , Excellent anti-oil, anti-grease and anti-vibration properties, it is a special colloid that has strong interstitial ability, wide operating temperature range, high pressure resistance, corrosion resistance and oil-carrying conditions.
- A variety of special additives are added to the high temperature-resistant sealant, and the inorganic structural adhesive with high temperature resistance to 538 ℃ is prepared by mixing. Drops or shortens due to changes in heat and cold.
- The fully cured silicone sealant can continue to be useful when the temperature reaches 204°C (400oF), but when the temperature is as high as 218°C (428oF), the useful time will be shortened.
- It is a silicone structural sealant, and its construction temperature range should be controlled between 5-40 °C. After full curing, its useful temperature should be kept at 204 degrees, and its useful life will be shortened when it exceeds 218 degrees.
- The high temperature sealant can be used in the temperature range of -55℃ to 200℃, and the higher temperature should not exceed 250℃ in a short time.
How long does the high temperature sealant take to dry?
- Sticking time
Different properties of silicone surface dry time and curing time are not the same. Acid glue, neutral transparent glue should generally be 10 minutes, neutral variegated glue should generally be 30 minutes.
- Curing time
(1) The curing time of the high temperature sealant increases with the increase of the bonding thickness. For example, the acid sealant with a thickness of 12 mm may take 3 to 4 days to fully solidify, but in this process, it is generally 24 hours The inner 3mm outer layer is cured.
(2) If the place where the sealant is used is partially or completely closed, the curing time is determined by the tightness of the seal. In an absolutely airtight place, it is possible to remain uncured forever.
How to use high temperature sealant
- Put the rubber nozzle on the hose, and then cut the nozzle obliquely;
- Clean the surface of the product material, and apply glue on the bonding and sealing position of the product;
- Aim at the bonding part and paste it, and press it to fit tightly;
- The initial positioning time is about 15-30 minutes, and the test is done after 24 hours.
What should I pay attention to when using high temperature sealant?
- The bonding surface should be kept dry and tidy, and there should be no residue of dust or oil.
- Cut the beak according to the actual needs, try not to cut it as large as possible, so as to avoid waste.
- The adhesive layer needs to be scraped flat before the surface is dry. Once cured, it will not be able to be scraped.
- After the sealant is completely cured, cut off the excess part directly with a blade.
Some industries do not have special requirements for the temperature resistance of sealants, and ordinary sealants can be selected. If the temperature of the working environment is too high, ordinary products cannot resist high temperature, and high temperature sealant can be used. It can be used for a long time at high temperature and will not be easily melted.