10 Things You Should Know Before Buying Liquid Silicone Rubber
Liquid silicone rubber (LSR) has become one of the most versatile materials in modern manufacturing. From electronics and automotive parts to medical devices and food-grade products, LSR offers performance that many other polymers simply can't match. But before you invest in liquid silicone rubber for your project or production line, there are several important things you should know. Understanding these factors will help you avoid costly mistakes and choose the right material for your application.
Here are 10 key things you should know before buying liquid silicone rubber:
1. Not All LSR Is the Same
Different grades of liquid silicone rubber are designed for different applications. Some are optimized for high-temperature resistance, while others focus on food safety, medical compatibility, high transparency, or mechanical strength.
Before buying, be clear about what properties you need.
2. The Mixing Ratio Matters
LSR is typically a two-component material(A/B), and the mixing ratio must be correct (commonly 1:1 or 10:1).
Choosing a product with a ratio that fits your equipment and process will save time and avoid defects.
3. Curing Conditions Can Affect Performance
Cure speed and cure temperature vary across materials.
Some LSR cures faster at high temperature, while others are designed for room-temperature curing.
If your production line has strict cycle time requirements, pick a material with a suitable curing profile.
4. Viscosity Determines Processing Difficulty
LSR comes in many viscosities. Low-viscosity materials flow better and are ideal for coating, dipping, and injection molding.
High-viscosity grades are better for **shaping, printing, or building thickness.
Make sure to choose a viscosity that works with your equipment.
5. LSR Offers Excellent Temperature Resistance - but Limits Still Apply
LSR generally works from –50°C to +250°C, and some grades go even higher.
However, choosing the wrong type for ultra-high-temperature applications can lead to yellowing, hardening, or loss of elasticity.
-6. Mechanical Properties Vary
Tensile strength, tear resistance, elongation, hardness, and compression set all differ by grade.
For example, coating fiberglass requires excellent adhesion and flexibility, while making a phone case requires impact absorption.
7. LSR Is Naturally Non-adhesive
LSR does not bond easily to most substrates without surface treatment or primer.
If your application involves metal, plastic, textile, or glass fiber, choose an LSR designed specifically for good adhesion.
8. Certifications Are Important
If your product touches skin, food, or goes into the medical field, you'll need compliance with standards such as:
* **FDA**
* **LFGB**
* **RoHS**
* **REACH**
* **ISO 10993** (medical biocompatibility)
Always check certification before buying.
9. Storage Life and Pot Life Are Not the Same
Shelf life: how long the material can be stored before use.
Pot life: how long A+B mixed material remains workable.
Some LSR has pot life as short as 30 minutes, while others can last several days.
Your process will determine which one is suitable.
10. Price Should Never Be the Only Factor
Cheap LSR often sacrifices:
* stability
* purity
* mechanical performance
* safety
* long-term reliability
Investing in a suitable, high-quality grade will reduce defects and improve product lifespan.