Antiblocking

S. antibioticus Antiblock agent Antiblocking agents Antibodies... 

Additives. Compounds are often added to the polymer at the extmder or melt homogenizer. Common additives are antioxidants (qv), thermal stabilizers, sHp agents, antiblock agents, anduv stabilizers. Popular antioxidants are 2,6-di-/-butyl-/)-cresol (BHT), octadecyl... 

Fiae sihca particles are iacorporated ia the surface of plastic films to preveat the adhesioa of two sheets ia coatact with oae another. The apphcation is called antiblocking. The relatively low refractive iadex of the sihca particles makes them more difficult to detect. 

Hunt et al. [354] used cSFC for the separation of extracts of poly(alkylene glycol) lubricants and sorbitan ester formulations. Doehl et al. [337] have compared the performance of cSFC-FID and pSFC-FID with both scC02 and scN20 in the analysis of the antiblocking agents oleamide and erucamide, the antistatic Armostat 400 and antioxidant Hostanox SE-10, none of which can be detected by UV absorption. By using open-tubular capillary columns, PAs as well as (un)substituted heavy carboxylic acids (> C ) can be eluted. 

Plastic foils used for wrapping TLC plates were once reported to contain amides of oleic, stearic, or palmitic acid as antiblocking agents which may migrate from the wrapping material [28]. Similarly, Amos [447] has encountered interferences from contaminants in solvents in the TLC analysis of phenolic AOs in turbine oils. 

While pure erucamide does not exhibit absorption in the 250-280 nm range all commercial products showed UV absorption maxima at 230, 257, 267 and 278 nm (with variable intensities), indicative of the presence of oxidation products (up to 8 wt%) as impurities with chromophoric groups. Colourless impurities do not have an interference effect. 1JV/VIS was also used to evaluate discoloration of 50wt/wt% mixtures of commercial erucamide and inorganic antiblock agents [59]. Apart from the interference by impurities from solvents chemical methods suffer from lengthy procedures. 

Intermaterial competition affects the additive business. For example, if metallocene polyolefins displace PVC markets, then the demand for heat stabilisers and plasticisers might decrease, while the need for products such as fluoropolymer processing aids, antiblocks and slip additives might increase. At present, PVC as the main user of additives is under threat as never before. However, green PVC, containing more environmentally friendly FRs and plasticisers as well as non-heavy-metal stabilisers, is now environmentally acceptable. 

See Antiblocking agents, Release agents, Slip agents. 

On a related theme, we can take advantage of the diffusion of molecules incorporated into a polymer to its surface. Thus we can blend lubricants, bactericides, and antiblock agents into polymers, which slowly exude to the surface where they perform a useful role. 

Antiblock additives are often incorporated into packaging films to prevent them sticking together. Their effectiveness relates directly to the roughness they impart on a film surface while minimising loss in optical properties. They are often used in association with slip additives such as erucamide. Common antiblock additives include crystalline silica, diatomaceous earth and talc (magnesium silicate). 

Antiblock additives can be seen on the surface of films using optical microscopy or SEM. Identification can normally be achieved with internal reflection IR spectroscopy (e.g., with a germanium crystal to minimise sampling depth) or using an X-ray attachment with the electron microscope. 

Microcrystalline waxes can also act as an antiblock and can provide some processing benefits. Polymeric antiblocks based on organic particles have also recently been introduced. 

Ecoflex Batch SL 1 Ecoflex Batch SL 2 Ecoflex Batch AB 1 Ecoflex Batch AB 3 Ecoflex Batch C White Ecoflex Batch C Black Lubricant Lubricant Antiblocking agent Antiblocking agent White batch Black batch 10% Erucamide ESA 5% Wax, additive 60% Eine chalk 40% Very fine chalk 60% Ti02 25% Carbon black... 

Antiblock agents like talc, chalk or silica can be used in form of masterbatches [23, 25]. The antiblock batches for processing Ecoflex and Ecovio are sold by BASF under the name Ecoflex Batch AB 1 or AB 3. 

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