Basic Knowledge of LSR

Liquid Silicone Rubber (LSR) consists mainly of silicone polymer and fumed silica being non-toxic and temperature resistant. It has the characteristics as follows.

• Heat resistant : Usable over 200 ºC for a long period of time
• Cold resistant : Flexible at -50 ºC ~ -90 ºC
• Good mechanical properties : At high temperature condition
• Good electrical properties : Less affected by temperature change
• Ozone resistant & Good weather ability
• Flame retardant : Low-toxic gas & good flame retardant

Classification	LSR	HTV
		Peroxide cure	Addition cure
Cure system	Addition cure	Peroxide cure		Addition cure
Process	Automation	Manual		Partly automation
By-product	none	A little		None
Cure rate	Very fast	Slow		Fast
Law material	Liquid	Solid
Material loss	Little	Many
Cycle time	Short	Long
Small quantities production	Not suitable	Suitable

LSR is cured automatically in liquid injection molding machines. Two Components (part A and B) are supplied at a regular ratio by dosing pumps. Part A and B are then mixed together in a mixing block and a static mixer. At this time, if color paste is necessary, it is then mixed. This mixed compound is measured by volume using some mechanical tools in the injection unit. Finally heat curing is done very quickly in a hot mold. After the fixed cure time, de-molding is completed and the cured articles are taken from the mold.

Liquid silicone rubber is heat resistant at high temperatures, such as 200℃. In addition, the cure system includes being cured by platinum catalyst.Therefore, it is physiologically inert. These properties make LSR applicable to baby nipples, swimming bands, mouthpiece for health care, food contact products for home appliances, and parts for electronics devices.
A full range of LSR products are offered by Sunoit Silicones including following different types:

1. General use type: nipples, keypads, kitchen wares, medical devices
2. Coatings grade: textile & fabric coatings, trademarks printings, #fibre glass coatings, non-stick stocks, etc
3. Insulators & cable accessories : Insulators , Surge arrester , Cable joint (cold shrink, etc.) , Cable terminators , Switch gear,etc