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Specialty Minerals Functional Fillers and Extenders for Reinforced Polyolefins

Reinforced polyolefin composites are used in transportation, consumer and other products because of performance and economy. Automotive components–exterior, interior and under-the-hood–are increasingly replacing metal parts for weight reduction, performance and appearance. Polypropylenes and thermoplastic olefins (TPOs), polypropylenes with synthetic elastomers added for strength are commonly used. Appliances such as washing machines and dishwashers now contain reinforced polypropylenes throughout. Stronger polyethylenes are also needed for the wider variety of household goods now injected-molded from this resin.


Minerals in Reinforced Polyolefins
Polypropylene, as the neat resin, generally has good strength but is not stiff enough for many uses. When the elastomer is added to form the TPO, impact strength increases but flexural modulus, a measure of stiffness, suffers. The addition of a fine or ultrafine talc will increase the stiffness of both the homopolymers and the TPOs. The finer the talc, the greater the improvement in flexural modulus, and the more of the original impact strength will be maintained. Adjusting the talc size, talc level and elastomer level can yield the desired stiffness/ impact balance for a given application.

As functional fillers, talcs improve physical properties such as dimensional stability by lowering the Coefficient of Thermal Expansion, as well as improving opacity, heat stability, and processability. Ultrafine talcs act as nucleating agents for polyolefins, which can reduce cycle times, increase production rates, and reduce compound costs. Densified forms of talcs are easier to handle and ship and can greatly increase the throughput of compound through extruders.

Ground calcium carbonates (GCCs) are often used as cost reducing fillers but, when finely ground, can also increase impact strength and add to flexural modulus. However, the flexural modulus increase will not be as great as for similarly-sized talc because of talc’s greater aspect ratio. Barite, also called barytes, provides excellent sound and vibration deadening and, where desired, can increase the density and weight of composites.


Specialty Minerals Products for Reinforced Polyolefins
Specialty Minerals Inc.’s (SMI’s) high quality mineral functional fillers and extenders enhance the performance and reduce the cost of polyolefin composites. Click on one of the product names below to download its technical data sheet. 

A broad variety of talcs are available, covering every application. 

  • FlextTalc® 610 talcs are fine and very bright for appearance grade applications such as automotive interiors and exteriors. Three SMI FlexTalc® talcs provide the highest brightness while yielding excellent stiffness in polypropylene and TPO composites. These talcs range in median particle size from 1.0 to 2.2 microns. The finest, FlexTalc® 610 talc, produces the best impact due to its fine median particle size. Each of the FlexTalc® talc grades is available densified or undensified. They are manufactured from bright Chinese ores in Mount Vernon, Indiana.
  • MicroTuff® AG and AGD talcs are fine bright talcs used when maximum performance and less than the brightest whites are required. Also, slightly better economy can be realized with these appearance-grade talcs. MicroTuff® AG talcs range from 0.8 to 1.8 microns and are coated for improved color and dispersion. The AGD series are densified for improved handling and processability. These are mined and processed in Barretts, Montana.
  • UltraTalc® 609 talc is the uncoated counterpart to MicroTuff® AG 609. It is a 0.8 micron Montana talc and the finest grade of general-purpose, lower brightness talc, which is ideally suited for applications that require high performance in darker-colored compounds.
  • MicroTuff® 100 series talcs are the uncoated counterparts to the 1.1 and 1.8 micron MicroTuff® AG talcs. These general-purpose, fine-ground Montana talcs economically add stiffness to low brightness composites.



To read more about SMI talcs for plastics, click here.

Three families of finely ground ground calcium carbonates (GCCs) for polyolefin reinforcement are also manufactured in the U.S. by Specialty Minerals.

  • Vicron® – East GCCs are high brightness GCCs with median particle sizes ranging from 3.5 to 10 microns. These products are produced in Adams, Massachusetts.
  • Vicron®– West GCCs are high brightness GCCs with median particle sizes ranging from 2 to 10 microns. They are produced in Lucerne Valley, California.
  • Rivercal™ GCCs are a family of bright GCCs for resin extension ranging in median particle size from 3.3 to 5.0 microns. The Rivercal™ GCCs are manufactured in Mount Vernon, Indiana from imported calcium carbonate ore.


To read more about SMI GCCs for plastics, click here.

For high density or sound deadening uses, Specialty Minerals has:

  • Baricron™ barytes/barites, which are produced in SMI’s Mount Vernon, Indiana plant using high-quality, bright-white ores from China. The Baricron™ barite family includes four products with median particle sizes ranging from 1.5 to 8.0 microns. Top size is carefully controlled and the products disperse easily for excellent surface finish.  

Click here to download the Baricron™ barites data sheet and click here to read more about SMI barytes for plastics.

 

 

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