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Introduction to Talc-based Antiblocks: What They Are and How They Work

Specialty Minerals Inc.s (SMIs) antiblock talcs are high-purity Montana talcs produced at our Barretts, Montana mine and manufacturing facility. These talcs are platy, exhibit high aspect ratios of approximately 20:1, and are substantially hydrophobic, thus leading to excellent compound dispersion in polyolefins. All SMI antiblock products are talc based, which makes them relatively low in abrasivity. Talc has a mineral Mohs hardness of 1, the softest mineral which occurs in nature. 

Antiblock Mechanism
Antiblocks function in polymer films by providing a balance between film physical property performance and efficient antiblocking with good optical clarity.

Antiblocks tend to produce microscopic bumps on the film surface which reduce film-to-film contact and thus reduce the tendency of film layers to stick together (i.e., the blocking force). 

The bumps induced by antiblock additives can be detected by atomic force microscopy (AFM).

Factors Affecting Antiblock Efficiency
The level of antiblocking activity will be affected by loading level (2,000-10,000 ppm is typical), the presence of other additives such as slip agents (e.g., erucamide), and process parameters. All of these factors have been studied extensively in our state-of-the-art film lab. Click on one of the links below to see the results of various studies using SMI talc-based antiblocks in a variety of blown and cast films.

Click here to download an introduction to antiblocks and SMI talc-based antiblocks in LLDPE films.

Specific application questions are often put to the test by running model formulations in our facilities to zero in on desired product performance. Click here to talk to us about your specific requirements.


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