Inorganic antiblocks

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. 

Inorganic antiblocking additives are frequently added in concentrations larger than required because they perform other functions, such as surface matting and plasticizer absorption. 

Other inorganic antiblocking fillers such as calcium carbonate, alumina-silicate ceramic spheres, zeolite, kaolin day, feldspar, and mica have also been used as antiblocks. In PE film, caldum carbonate can provide the low blocking force of talc and DE, but only when loaded at 2-3 times their concentration (or higher), reducing darity of the film, and increasing its density [12-1, 12-22, 12-30]. 

Table 12.2 Antiblocking and Clarity m-LLDPE Film Data for Common Inorganic Antiblocks in 25- im ...

Antiblock additives can be divided into two classes inorganic and organic. Chemically inert, inorganic antiblock additives migrate to the film surface and partially stick out of the surface to create a microroughness of the film surface. Figure 1.21 illustrates this principle. 

Peloso, C.W. et al. (1998), Characterising the degradation of the polymer slip additive erucamid in the presence of inorganic antiblock agents, Polym. Degrad. Stab., 62 (2), 285-290. 

Further, abrasion may be a problem in the course of processing if the hardness of the inorganic antiblocking agent is too high. For example, talc is much more soft than silica and causes a least abrasive level to the processing engines (2). 

Some data included in the tables for inorganic antiblocking agents are taken from a monograph on fillers. Performance characteristics are adjusted to reflect properties required for antiblocking agents, if they differ from general purpose fillers. A handbook on fillers contains additional information on particular materials, which is not repeated in this book. 

Properties and performance of inorganic antiblocking additives are not affected by solubility but this is the only exception. Organic antiblocking, release, and slip additives perform in accordance with their solubility in systems into... 

This reaction has implications for the rheological properties of slip agent. The amount of absorbed binder (acrylic acid homopolymer), its pIQ, pH, time, and other additives (dispersant) influence rheological properties." Also, silica particles are able to form ionic associations, and this may be important in the case of inorganic antiblocking agents used in some formulations. 

Two major directions of research are important for improvement of performance of inorganic antiblocking additives better optical clarity and elimination of influence on slip additives. Antiblocking inorganic additives increase haze and reduce gloss. Some improvements in optical qualities of talcs were reported. ... 

Blocking force of pol5miers containing inorganic antiblocking additives depends... 

Some of the above influences, such as pore volume and interaction between additives, are related to inorganic antiblocks and others, such as time after processing, material thickness, and transfer of surface components to other materials, are characteristics of organic additives. The parameters from the above list are discussed in the same order below. 

Optical properties are most likely affected by inorganic antiblocking agents. 

Figure 10.31 shows that inorganic antiblocks do not affect gloss. ... 

The discoloration of polymeric materials containing inorganic antiblock additives is most likely caused by impurities contained in these products. Iron and titanium compounds are considered to be capable of forming colored complexes. " ... 

Barrel, head, and gate pressures are frequently reduced by the presence of additives (see example in Figure 10.38). Reduced gate pressure and lower torque resulted from addition of fluoropolymer additive. Melt viscosity usually increases with the addition of inorganic antiblocking additives. When fluoropolymer additive was added, it reduced viscosity so that a combined action of the two reduced head pressure by about 20%. This reduction depends on the types of additives. The antiblocking additives which absorb a process additive will cause higher head pressure. ... 

Many aspects related to the surface of electronic components were recently discussed, such as, effect of composition of the passivation layer on adhesion in flip-chip packaging, use of time-of-flight secondary mass spectroscopy in detection of mold release agents in near surface regions, x-ray lithography, defects of coatings in the presence of inorganic antiblocks, use of silicon nitride molds " and diamond dies, and nanoscopic pattern transfer. ... 

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