Views: 252 Author: Site Editor Publish Time: 2020-09-11 Origin: Site
Can Silicone/Liquid Silicone be UV Resistant?
What is Silicone?
Silicone called polysiloxane, is an inorganic polymer comprising of carbon, hydrogen and oxygen, any of a diverse class of fluids, resins, or elastomers based on polymerized siloxanes, substances whose molecules consist of chains made of alternating silicon and oxygen atoms. Silicone's chemical inertness, resistance to water and oxidation, and stability at both high and low temperatures have led to a wide range of industries.
What's the General Proeprties of Silicone? Does silicone itself resist UV?
Heat/Cold Resistance: The siloxane bond that form the backbone of silicone are highly stable and their binding energy is higher than of carbon bond. Silicone Rubber withstands high and low temperature than organic rubbers. It withstands 200°C for 10000 hours or more. Silicone rubber can withstand -60°C to -70°C, which is better than typical organic rubber between -20°C to -30°C.
Good Weatherability: Silicone rubbers have excellent weatherability. Ozone created by corona discharge deteriorates most organic rubbers, but has almost no effect on silicone rubber. What's more, silicone rubber can be exposed to wind, rain, and UV rays for a certain periods with no change in it physical properties. So silicone rubber itself has UV resistance property, while for some product need higher UV resistant demands, silicone can not meet the requirement. Will need to add UV Resistant agent in to the material to test and to achieve the requirement.
From silicone's general properties we know that Silicone itself is UV resistant, but if the level is high, will need to add anti-UV agent to achieve better results. Normally sunlight, especially the ultraviolet radiation in sunlight, is often an important reason for the aging of silicone insulation materials. Therefore, it is very necessary to perform artificial accelerated aging tests on silicone by simulating sunlight.
Silicone is a highly active adsorption material, which is usually prepared by reacting sodium silicate and sulfuric acid and undergoing a series of post-treatment processes such as aging and acid foaming. Due to the use of time and high temperature or aging in a complex environment, some of its parameters will change, such as increased hardness, reduced strength, shorter elongation, etc.; characteristics can be distinguished from the color, such as yellower than normal.
The purpose of the aging test is to use the laboratory equipment in the shortest time to simulate the change of the insulation performance of the insulating material under long-term operation in actual operation. As a result, scientists from foreign experimental research departments have done a lot of research and experimental exploration, and finally determined the experimental method of simulated accelerated aging of insulating materials.
What is Anti-ultraviolet Silicone?
Anti-ultraviolet silicone has excellent resistance to severe cold and high temperature. Common silicone can withstand high temperatures between 200 and 300 degrees, while anti-ultraviolet can work at high temperatures up to 350 degrees for a long time. In the working environment of low temperature -60 degrees, good weather resistance: moisture-proof, anti-vibration, anti-ultraviolet, waterproof, will not change due to bad weather conditions, generally suitable for molding, extrusion, calendering and supply.
Anti-ultraviolet silicone's Excellent Properties:
1. UV protection
2. Corona resistance
5. Superior thermal conductivity
6. Good electrical insulation performance
7. Strong sealing
For many silicone gaskets need be exposed outdoors, Anti-UV silicone is best choice. Generally divided into five levels, level 1, level 2, level 3, level 4, and level 5. The higher the level, the higher the yellowing resistance level.
Anti-UV Silicone's Applications:
Lead wires of motors and home electronic goods
Heater wires of rice cookers, etc.
Refrigerator defroster wires