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Adhesives Ingredients
The material selection platform
Adhesives Ingredients

2K RTV Silicone Adhesive or Sealant

Adhesives Formulation

Applicable Type
Applicable Base Polymer

Applicable Base Polymer Properties

Silicone polymers display an exceptionally wide range of chemistries and physical properties. These polymers can be low viscosity liquids, crosslinkable elastomers, or hard solids. Adhesives and sealants represent only one major class of commercial silicone products. These versatile materials were introduced approximately 30 years ago and many of the original formulations are still utilized.

Two-part condensation cure silanol systems employ ethyl silicates (polydiethoxysiloxanes) such as PSI-021 as crosslinkers and dialkyltincarboxylates as accelerators. Tin levels in these systems are minimally 500ppm, but typical formulations have up to ten times the minimum.

Typical Formulation Ingredients

Phase
Ingredient
Parts by weight
Polydimethylsiloxane (PS44, UTC Specialties LLC) 
xxx 
Silica, hexamethyl disilazane treated (SS0216, UTC Specialties LLC) 
xx 
Methylhydro,dimethylsiloxane copolymer (PS123, UTC Specialties LLC) 
xxx 
Platinum divinyltetramethyl disiloxane complex (PC075, UTC Specialties LLC) 
xxxxxxxxxxx 
Polydimethylsiloxane (PS44, UTC Specialties LLC) 
xx 
Methylhydro, dimethylsiloxane copolymer (PS123, UTC Specialties LLC) 
xx 

Typical Properties

Properties
Mix ratio (Part A : Part B) by weight 
xxx 
Cure time at room temperature, hours 
x 
Tensile strength, psi 
xxx 
Tear strength, ppi 
xx 
Hardness, Shore A 
xxxxx 
Elongation, % 
xxxxxxx 

Processing

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Resulting Properties

RTV silicone sealants offer superior durability in most environments. These materials bond readily to many substrates and provide excellent elongation. They bond well to many low surface energy plastics due to the relatively low surface tension of the RTV silicone formulations. However, RTV silicone products do not have the high degree of tensile strength or tear and abrasion resistance as epoxies and polyurethanes. For this reason RTV silicone formulations are more commonly used as sealants than as adhesives although they are also often utilized as coatings and soft potting compounds.

(Source: UTC Specialties LLC)

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