Low shrink

Properties transparent molding low-shrink copolymer mineral-filled reinforced unfilled... 

The error, ER, would simply be the difference between the SDi and SEE equations. To be more accurate for calculating mold dimensions where the product size and shrink rate increase, this error value should be considered or Table 3-16 is be used. This table shows, as one example, which in the low shrink (0.008 mil/in. or less) materials, the products must be larger than 15 in. 

Amorphous polyimide powders prepared by dissolution/precipitation processes, can be used to toughen thermosetting polymers. Polyethylene powders are frequently used in low-shrink unsaturated polyester formulations. 

Some new types of S-B block copolymers are now being used as low-shrink/low-profile additives in sheet molding compounds made from unsaturated polyesters. 

LS low shrink MACT maximum available control technology... 

Refers to low profile RJ surfaces. These are special TS polyester compounds for RPs that are combinations of thermoset and thermoplastic materials. Although the term low profile and low-shrink are sometimes used interchangeably, there is a difference. Low-shrink contain up to 30wt% TP, while low-profile contain from 30-50wt% TP. Low-shrink offers minimum surface waviness on molded parts, as low as 25 pm (1 mil) per in mold shrinkage whereas low-profile offers no surface waviness of 0-12.7 pm (0-0.5 in) per in mold shrinkage. 

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. 

Polyester bulk molding compounds (BMCs) are widely used for large electrical switchgear moldings, and the latest types of low-shrink high impact BMCs are used for the housings of power tools and small kitchen appliances that must meet severe impact standards and may also have to resist heat. 

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. 

Advantages low shrink temperature, broad heat-seal range, good low-temperature properties... 

W.M. Palin, G.J. Fleming, F.J. Burke, P.M. Marquis, R.C. Randall, The influence of short and medium-term water immersion on the hydrolytic stability of novel low-shrink dental composites. Dent. Mater. 21 (2005) 852-863. 

Low shrink (LS) and low profile (LP) systems have been developed over the past 20 years for large-surface parts in car bodies such as bumpers, trunk lids, doors, fenders, etc. 

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