Introduction
There are many liquid silicone rubber misconceptions associated with wide applications and performance. Liquid silicone rubber is easily found in everywhere around us. Such as appliances, electronics, automotive, beverage, construction, and toys. The silicone family is consisting of enormous variety of compound, it is the most withe widestde used material family in the world.
We are trying to explain each misconception with accurate information, in order to prevent practitioners from applying silicone materials with full confidence.
Misconception List
Silicone is a Chemical Ingredient
As normal silicone parts are lubricating oils, cosmetic ingredient, or soft coverage in our mind, it is easily confused with silicon. In fact, silicone is referred to a material family of chemicals with different physical forms: liquid, gel, solid. While silicone rubbers are long macro-molecules with silicon (Si) and oxygen (O) bonds, they have different properties depending on specific arrangement.
Silicone Rubbers are Synthetic Materials
Silicone rubbers, or liquid silicone rubbers, are synthetic materials by complex synthesis process, which is created by humans. However, the raw materials for silicone is completely natural, silica or sand is in form of silicon and oxygen. Therefore, we should clarify the confusion of silicon, silica and silicone. Silicon is a chemical element, while silica is a compound of silicon dioxide. In addition, silica is the raw materials to produce silicone family of materials.
Liquid Silicone Rubbers are Only Processed and Applied in High Temperature
There are different type of silicone for different temperatures and conditions. Room Temperature Vulcanization (RTV) silicone rubber can be processed and applied at room temperature. Otherwise, we can also modify liquid silicone rubber materials by additives. In order to mold and vulcanize these LSR at low temperatures for electrical and electronic applications.
Liquid Silicone Rubbers are Tacky
As in our tactile feel of silicone rubber, we tend to determine all silicone rubber are sticky and tacky. However, depends on processing and application requirements, we will modify liquid silicone rubber to eliminate the sticky feeling on final LSR parts surface. Such as, in medical application with liquid silicone rubber, the surface must be as smooth as possible without any tacky. In this case, we should modify the silicone rubber formulation with Mica additives, or change the processing conditions.
Silicone Rubbers are Soft and Flexible
In reason of our common, silicone rubber parts are soft and flexible. People believe that all silicone rubbers have low hardness and low mechanical properties. However, there are many methods to increase silicone rubber hardness, like creating more crosslinks in molecular structure, or adding specific fillers. Such as, the optical liquid silicone rubber can reach to hardness of 70 Share without any elasticity. We can provide different grades of liquid silicone rubber with hardness from 30 Shore to 80 Shore.
Silicone Rubbers Generate Fumes in Burning Process
People always confuse silicone rubber and thermoplastics, they believe that all these materials will generate fumes and gases in burning process. Therefore, this is a main disadvantage for certain application in extreme environment with high temperature. Actually, silicone materials are natural self-extinguishing. Furthermore, we also can add flame retardants into silicone rubber, depends on detail compounding. In order to eliminate gases and fumes generation completely with standard requirements.
Silicone Rubbers Result to Atmospheric Contamination
In reason of silicone rubber is inorganic natural, its compounds or mixtures don’t contain chemical types with atmospheric contamination. The normal chemicals with environment contamination are volatile organic compounds(VOCs), such as alcohols, acetates, methiacrylates, acetones. In addition, chlorofluorcarbon compounds (CFCs) are also identified to have impact on the ozone layer.
Silicone Rubbers Require Thousands of Years to Degrade
From a biological aspect, silicone rubber is not biodegradable. However, its silicon-oxygen can be degraded into water, carbon dioxide and silic acid in certain environmental situations. Furthermore, once silicone rubbers are buried, soil minerals will accelerate the chain scission in only days. Then, sunlight and atmospheric oxygen will create low molecular silicone chains.
Silicone Rubbers Give Rise to Allergies and Irritations
There are many studies and researches on this subject, unlike natural latex rubber and other rubbers, silicone rubber won’t create allergic reactions and skin irritations. Actually, silicone or liquid silicone rubber materials have biological inertness, this is an excellent advantage of LSR materials.
Silicone Rubbers Accumulate Biologically in Human Body
Bio-accumulation is the accumulation of toxic substances in living organism tissues. In extensive testing of silicone rubber, it has superior compatibility with human tissue and body fluids. Comparing with other elastomers, silicon rubber also has extremely tissue response in implants. Silicone materials are odorless and tasteless, they resist bacteria growth and never corrode other materials. Normally, liquid silicone rubber materials are complied with FDA, ISO and Tripartite bio-compatibility guidelines for medical products.
Silicone Rubbers Cause Disease
There is a concern about whether silicone rubbers cause diseases, as many silicone rubber applications are in contact with human body and food. However, from chemical aspect, these applications only release big molecules, these molecules cannot penetrate human tissue. Therefore, silicone rubbers will never cause diseases with contacting. Furthermore, the FDA (Food and Drug Administration) has very strict regulation of food grade liquid silicone rubber. Any LSR materials in food & beverage industry must be in compliance with these regulations.
Conclusion
Silicone rubber, or liquid silicone rubber, is a safe material in our daily life. Miwo is able to produce different silicone parts with specific property requirement. Contact our engineering team now for your unique silicone products.
