Silicone Sealant is generally available in paste form . It cure ( dries) after reacting with moisture to form rubber like flexible compound , it also releases a by-product during this curing process . Based on the by-product generated Silicones are classified into two categories . Neutral & Acetoxy Silicones .
Sealing and Bonding – bonds to different surfaces like Wood, metal, Concrete, Plastics, Glass . Popularly used across spectrum of industries like Construction, Automotive, Manufacturing, Maintenance, Aerospace, Glass etc.
Types of Silicone Sealant
Silicones are further classified based on their curing systems
Acetoxy - Cure Systems
Most popular & used extensively due to lower costs.
- Disadvantages: not sensor safe, corrosive due to acetic acid vapours released during curing, cannot be painted over, strong smell.
- Applications: Gap-filling, high temperature (300°C) sealing, any general-purpose sealing/bonding application.
Neutral - Cure Systems
Higher grade Silicone sealants used for technical and critical applications.
- Applications: Flange sealing in Automobiles, manufacturing, Plant maintenance, Food and Pharma plants for general bonding/sealing, External window gap sealing, Glass Bonding, glazing , weather sealing.
Popular grades of Silicone Sealant used.
General / All Purpose Silicone Sealant
Top selling product amongst Silicones. Acetoxy cure , low cost , low elongation, Resistant to Sunlight, suitable for general gap filling applications. More than performance, price is an important criteria for product selection. Bonds to most substrates except PP, PTFE, LDPE, HDPE and low energy substrates.
These sealants ideally suited for sealing, glass, windows, shopfront, aluminium joints, showcases, bus body building and automobiles
Building- and construction joints , Glazing and connection joints, elastic joints in coldstore and container applications, Sealings in air condition systems ,General sealing for automotive applications
GP Silicone Trend in India.
Can be subgrouped into three categories :
- Highly quality GP Silicones from reputed Brands like Dowsil, Wacker, Momentive, Mccoy, Boss . etc.
- Cheap priced imports from China : importers get low quality cheap products which is sold extensively through retail / Hardware Shops. Typically they sell at low price by reducing quantity of Sealant in the cartridge ( around 220 ml instead of 280 or 300 ml ). They have lower shelf life too.
- Branded Silicones sealants which are typically in between the low cost sealants and high quality reputed branded GP sealants . Priced also in the middle bracket. Typical examples: Dr Fixit, Anabond , Smartcare ( Asian Paints) Resibond, Astral, Abro, Alstone etc.
Packing: 260 ml , 280 ml , 300 ml cartridge
Colours Available : Translucent, White, Black . Other special colours as per requirements.
These Sealants are used for typical construction applications.
Neutral Cure glazing silicone sealants very popular for its bonding capability with Glass and metals. Also excellent weathering ability makes it popular to be used against water / atmosphere ingress in metal structures and civil constructions.
Excellent adhesion properties on glass, laminated glass, coated aluminum, galvanized steel, concrete and masonry.
High tensile strength and high elongation properties.
- For weatherproofing sealing nonstructural curtain wall joints,facade joints
- Weather sealing in metal, glass,stone,aluminum panel, and plastic
- All usual building, connection, expansion and dilatation joints
- Excellent for double glazing system applications.
- Weather sealing of expansion joints in the facade industry
Packings : 280 , 300 ml cartridge, 600 ml sausage
Colours: Black,White, Translucent, Grey
Weather Silicone Trend in India.
Can be differentiated in 3 categories
- Most Popular and Highest selling weather silicone : Dowsil 789
- Reputed brands like Wacker, Boss, Mccoy, Momentive etc
- Cheap Chinese imports
However this being a crtitical application , contractors prefer to use reliable brands though a little costly.
General Purpose Neutral cure Silicones
GP Neutral cure silicones sealant is cost effective, multipurpose, neutral cure silicone sealant.
– One-component sealant/adhesive
– Cures at room temperature
– Excellent UV moisture resistance
– Good adhesion to most common construction substrate like concrete, metals, plastics
– Good waterproof and weatherproof for interior & exterior applications
GP Neutral silicones sealant will bond to make strong weatherproof seal on most common
building material like glass, concrete, aluminium, brick, steel, ceramic, plastic and most porus & non porous Substrates.
Features and Advantages
- Neutral cure/low odor
- Low modulus
- Excellent adhesion to vinyl, wood, steel, aluminum, glass and plastic
- VOC Compliant
- Sealing electrical equipment
- Bonding appliance parts
- Permanently flexible
Packing: 280 , 300 ml cartridge .
Colours : Translucent, Black, White, Grey . Special colours are made as per request.
High Temperature Sealants
These Silicones have high operating temperature capability ranging upto 450 C.
Apart from high operating temperature capability they are characteritized by :
- Excellent adhesion or bonding strength
- Resistance to chemicals, fuels
Generally used for high temperature Gasketing ( flange sealing) , sealing & bonding for Ovens.
Food grade Sealants
Food manufacturing plants , pharma units , clean rooms have very stringent norms to adhere too.
Any chemical used in the plant which directly or indirectly comes in contact with the End product has to be ‘FDA’ approved ,ie: is safe even if the used chemical comes in direct contact with the end product manufactured . Eg: Medicine manufacturing unit, Horlicks manufacturing plant.
For such situations customer insist of food grade approved sealants.
These are regular sealants used for gap filling, flange sealing, general bonding and sealaing. However these are manufactured such that it passes FDA strict norms for incidental food contact .
Packing: 280 , 300 ml cartridge
Colours : Translucent, White, Black
Automotive/ Industrial Silicone Sealants
You name any 2 or 4 wheeler, truck, tractor, Stationery engines, Generators, construction equipments like Tipper, Trailer, Payloader, Dumper etc – all have been sealed using advanced silicone sealants . Typical Automotive Engine applications include
Oil sump to engine block flange sealing
Transmission cover sealing
Cam Shaft cover sealing
Engine Block to Head Flange sealing .
There are various sealing & bonding applications accomplished using such sealants.
Typical properties of Automotive / Industrial sealants
- High tensile strength
- High movement capability , elongation
- Resistance to chemicals, fuel , engine oil, transmission oil.
- Easy removal from the surface while overhauling and applying new sealant.
- Non corrosive and sensor safe – typically neutral cure silicone is used.
- High temperature resistance , from 150 to 450 C
- Withstand internal pressure upto 10 Bars
Structural Silicone Sealants
Silicone structural glazing is the use of a silicone sealant for the structural transfer of loads from the glass to its perimeter support system and retention of the glass in the opening. … Insulating glass used in structural glazing must have silicone units
Wind load and other impact loads on the façade are transferred from the glass or panel, through the structural silicone sealant to the structure of the building. The silicone sealant must maintain its adhesive and cohesive strength on the facade when subjected to wind loads and thermal stresses.
The one part structural silicone sealant packaging options allow for more flexibility of use by the installer, as the silicone can be conveniently used on building sites with minimal fuss.