Liquid Silicone Rubber vs. Traditional Silicone: What's the Difference?
Liquid Silicone Rubber (LSR) and traditional silicone (also called high-consistency silicone rubber, HCR) are both silicone-based materials, but they differ significantly in form, processing, performance, and applications. Here's a clear comparison:
1. Form & Viscosity
Liquid Silicone Rubber (LSR)
* Low viscosity, flowable liquid
* Comes in two parts (A/B) mixed at a fixed ratio
* Suitable for injection molding and coating
Traditional Silicone (HCR)
* Thick, putty-like, gum-based material
* Requires mechanical mixing, milling, or extrusion
* Used for compression molding or extrusion
2. Processing Method
LSR
* Processed by liquid injection molding (LIM)
* Automatic, fast, stable, continuous production
* Suitable for high-volume mass manufacturing
HCR
* Processed by **compression molding, transfer molding, or extrusion
* More labor-intensive and slower
* Better for thick parts or small-batch/custom products
3. Curing & Crosslinking
LSR
* Platinum-catalyzed (addition cure)
* Rapid curing at high temperatures
* Low shrinkage and high precision
HCR
* Peroxide-cured or platinum-cured
* Slower and may release by-products (if peroxide type)
* Larger dimensional changes
4. Mechanical Properties
LSR Advantages
* Excellent consistency in quality
* High transparency available
* Superior mechanical stability and resilience
* Good for thin-walled or micro-molded parts
HCR Advantages
* Higher tear strength and toughness
* Better for thick, robust industrial parts
* Easier to reinforce with fillers
5. Temperature & Chemical Resistance
Both have excellent performance, but:
LSR
* Outstanding heat stability and cold flexibility
* Better long-term aging performance
HCR
* Excellent heat resistance
* Better suited for very high-strength applications
6. Applications
LSR Applications
* Baby products (nipples, pacifiers)
* Medical devices
* Electronics sealants
* Wearable devices
* Keypads, kitchenware
* Coating (textiles, fiberglass, wires)
HCR Applications
* Automotive hoses
* Gaskets, O-rings
* Extruded profiles
* Thick industrial components
* High-strength mechanical parts
7. Cost & Efficiency
LSR
* Higher material cost
* Lower overall production cost for mass manufacturing
* More suitable for precision parts
HCR
* Lower material price
* Higher labor and processing cost
* Better for low-volume, high-strength needs
Summary Table
Feature LSR (Liquid Silicone Rubber) Traditional Silicone (HCR)
Form Liquid Solid Gum
Processing Injection Molding (LIM) Compression/Extrusion
Curing Platinum only Peroxide or Platinum
Precision Very high Moderate
Tear Strength Medium High
Transparency Excellent Limited
Automation High Low
Best For Medical, baby, electronics, precision Auto, industrial, thick parts