Liquid Silicone Rubber Materials LSR For Molding

Stockwell Elastomerics is a number one manufacturer of liquid silicone rubber (LSR) based merchandise using its extensive in-home silicone rubber molding operations. LSR is a versatile elastomer that can be molded into sheets and cast into steady rolls for die slicing or waterjet chopping.


Stockwell Elastomerics applies acrylic strain delicate adhesives onto LSR sheets and rolls for adhesive backed gaskets. One of Stockwell Elastomerics’ specialties is applying movie supported acrylic adhesives, akin to 3M 9415 or Adchem 256M and 3M 467 transfer film adhesive onto .010″ and .020″ thick solid liquid silicone rubber for display gaskets and silicone mold related purposes requiring a very thin gasket.


Stockwell Elastomerics also injection molds customized 3D elements per customer specs. LSRs have a large temperature vary (-58°F to 392°F) and can be made in broad durometer vary (10 - 80 Shore A) with out plasticizers. Silicone’s glorious rebound, UV and ozone resistance makes it perfect for outside sealing and will be use for submerged gaskets (IP67 and NEMA 6). Stockwell Elastomerics maintains in-house stock of silicone sheet, silicone rolls and molding compounds to be injection molded for quick response occasions.

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Contains small samples of cured LSR materials to contact and feel.

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What is Liquid Silicone Rubber?


Liquid silicone rubber (LSR) could be very low viscosity silicone that can be injection molded or forged into silicone rubber sheets. "Liquid" is explicit in the title to differentiate LSRs from excessive consistency gum based silicone merchandise. LSRs are addition cure / platinum cure systems in contrast with most gum based mostly silicones which can be peroxide cured. In its raw uncured form, LSR is two parts liquid that are mixed together (mixing of Part A and Half B begins the curing) and heated to speed up the curing course of. Raw gum primarily based silicones appear and feel just like clay. LSRs are generally injection molded or solid whereas gum based mostly silicones are sometimes compression molded. Note that injection molding of liquid silicone rubber is the inverse of molding thermoplastics; room temperature liquid silicone compound is injected into and cured in a sizzling mold vs. plastic pellets melted into sizzling liquid and forced into a cooled mold.

Silicone Materials Selection Information

Why Specify Liquid Silicone Rubber?


Efficiency properties and quick cure cycles make liquid silicone rubber a good selection for small molded parts. In contrast to most thermoplastic elastomers (TPRs and TPEs), LSR stays versatile and elastic all the way down to -58°F and retains its properties as much as 392°F. Liquid silicone rubber is an efficient candidate for gaskets, seals and cushioning pads in portable communications, knowledge acquisition devices and ruggedized electronic devices the place outside conditions are demanding. The cure cycles in liquid injection molding permit for a 1 or 2 cavity mold to out-produce a compression mold with the next cavity rely.


Beyond the mechanical, chemical, and thermal properties of LSR, there are numerous different reasons to specify this sort of material. From a manufacturability standpoint, a number of key elements stand out. Certainly one of the largest causes that customers may find yourself going with LSR materials is geometry. Any kind of 3D form that can't be fabricated in a flat configuration would require a molding process - normally with elements like this, a excessive manufacturing amount degree justifies the added cost of tooling that's related to LSR molding.


Moreover, some customers could have flat gaskets, but with very tight thickness tolerance wants. In these cases, Stockwell Elastomerics can leverage its sheet molding capabilities to carry tighter tolerances in small sheets, which may then be used to die-cut or waterjet reduce flat gaskets and pads.

Transitioning from Flat Prototypes to Molded Production Elements

Once in a while, clients wish to transition from flat reduce parts to molded components. As customers work by way of small prototype runs of initial designs, Stockwell Elastomerics supports this modification with fast turn waterjet reduce gaskets utilizing molded LSR sheets. As designs develop and molding is required, the same material can be utilized. This eliminates re-testing and re-validation, since the material is the very same for the prototypes and silicone gadget production elements.


For elements without any sort of 3D geometry, molding can be a really cost efficient answer at high quantity production, as conventional die-chopping and waterjet chopping have wasted material cost. For instance, a small window gasket may be quite price efficient to supply in small quantities as a waterjet minimize part, but as manufacturing quantities enhance, the mixed cost of the wasted window cutout can add up. In circumstances like this, paying to software-up a production LSR mold creates a way more value-efficient answer trimmed piece worth down the road.

Cure Catalysts - Tin vs. Platinum

In LSR materials, a catalyst is required as a part of the curing process. Widespread cure catalysts are tin (also referred to as condensation cure) and platinum (also called addition cure). All of Stockwell Elastomerics’ LSR products are platinum-cured.


Platinum-cured LSR is often "cleaner" than tin-cured LSR - for this reason lots of Stockwell Elastomerics’ LSR merchandise are appropriate for use within the medical gadget industry. Platinum-cured LSR is often capable of assembly FDA and USP Class VI certifications. Platinum-cured LSR may survive increased temperatures when in comparison with tin-cured alternate options.


Tin-cured LSR is often found in shopper and inventor-grade material. If you have any questions regarding where and ways to utilize silicone gadget, you can contact us at the web-site. This material can cure utilizing condensation from the air and doesn't require heat. Tin-cured LSR is typically not FDA grade and isn't used in additional demanding purposes.


While tin-cured LSR is extra accessible for interest-grade and varied shopper purposes, it does not offer among the distinct advantages and excessive-performance traits of platinum-cured LSR. This is the reason platinum-cured LSRs used solely - these supplies best serve customers in core industries served by Stockwell Elastomerics.

Liquid Silicone Durometer Vary

LSR is available in a hardness range of 10 to eighty durometer Shore A. 10 durometer LSR is very smooth like chewing gum and can really feel softer than some extra agency silicone foam and silicone sponge merchandise. 80 durometer LSR is tougher than a heel of a shoe and is as firm as many thermoplastic elastomer merchandise. Most purposes for LSR are specified within the 20 to 60 durometer Shore A spread.


Stockwell Elastomerics’ Liquid Silicone Rubber Touch Brochure can help with selection of material hardness for specific functions. The tensile, elongation and tear resistance properties of liquid silicones have improved since the preliminary commercialization of LSR.

Liquid Silicone Rubber Availability

Stockwell Elastomerics gives off-the-shelf LSR sheets (12″ x 12″) and steady solid rolls with or with out film supported acrylic or acrylic switch film adhesive options. The 12″ x 12″ molded sheets are available from .032″ to .125″ thick. Stockwell Elastomerics’ on-site molding facility supplies molded and cryogenically deflashed, customized liquid silicone gaskets and a wide range of custom parts.