Low shrink SMC

LS-SMC (low-shrink SMC) Slightly higher shrinkage than LP-SMC, but less than 1 vol%. It usually comprises pigmentable TP polyester mixtures particularly when making thick laminates for large structures. 

An unaccelerated resin specifically designed for the manufacture of low shrink, SMC/BMC moulding compounds. 

A medium to highly reactive isophthalic base resin suitable for low profile/low shrink SMC/BMC manufacture. Thickenable. 

Uses Wetting agent, dispersanf flow aid tor hot curing, fiber glass-reinforced or low-shrink SMC/BMC/DMC formulations based on unsaf polyester and PS or unsat. polyester and S/B copolymers filled with calcium carbonate, alumina trihy-drate... 

Shrinkage Any filler will decrease shrinkage the most commonly-used fillers are silica, clay, calcium carbonate, alumina talc, powdered metals, and lithium aluminum silicate. Low-shrink or low-profile additives are used in TS systems such as SMCs and BMCs to minimize shrinkage during and after molding, and improve the surface appearance of a molding. 

Some thermoplastic polymers commercially used as the low-profile, low-shrink additives to SMC and BMC composites are... 

Properties ASTM te t m tho< SMC low-shrink BMC, TMC SMC. TMC BMC 50% glass fibar rainforosd Granular and putty, minaral- filled Glass fibar> rainforoad... 

Rnbber or elastomeric additives have been found to be effective low-shrink/low-profile additives for sheet and bnlk molding compounds (SMC and BMC). These additives include butadiene/styrene and styrene/butadiene/styrene. For maximum surface properties, 15 weight percent of the additive gives good molded appearance even in large, relatively fiat, thin panels. 

Properties ASTM Test Method SMC Low-shrink BMC, TMC SMC, TMC BMC Granular 50% Glass Fiber-reinforced and E itty, Mineral- liUed Glass Fiber-reinforced... 

A low shrink, low profile resin containing vinyl ester for SMC and BMC applications, with high heat resistance and high tensile elongation. Can be employed as a low profile additive - see section H8. 

A highly reactive, high viscosity orthophthalic resin which in combination with low shrink and low profile additives, is suitable for SMC manufacture and then car body, furniture and electrical mouldings, b. 72% c. 3900-4910... 

A PSM-based low-shrink additive for SMC BMC, having high compatibility with PS. 

A white, free flowing paste-like solution or dispersion of thermoplastic polymers and fillers for low-shrink application in highly reactive fire retardant, SMC/BMC and puitrusion resin systems. 

A hybrid thermoplastic polyester resin formulated for use in SMC/BMC applications and containing 22% recycled content. The resin provides excellent low profile properties for both structural and zero shrink applications and is soluble in many types of unsaturated polyester resin. It may be thickened using standard alkaline oxides and/or alkaline hydroxides and offers superior hot strength, impact properties and excellent bond and paint adhesion. 

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