Particle size antiblocking agents

Run Talc Antiblock Mean Particle Size ( jjn) Talc Antiblock Concentration, ppm Emcamide Slip Agent Concentration, ppm Film Thickness, mils (pm)... 

In packaging films, synthetic or natural silicas and minerals are common antiblocking agents. Performance is affected by both shape and size of the particles. As a rule, finer particle sizes are used in thin films, and larger particle sizes in thicker materials. The preferred average particle size for antiblocking agents in LDPE and PP films is 6 to 20% of the film thickness. 

Aerosil 0X50 [Degussa/Aerosil Silanes Degussa AG/Aerosil Silanes] Chem. Descrip. Fumed silica CAS 112945-52-5 EINECS/ELINCS 231-545-4 Uses Filler for plastics, silicone rubber antiblocking agent for PET, PP and PE films and tapes for coating of elec, light bulbs Properties Wh. fluffy powd. 40 nm avg. particle size sp.gr. 2.2 dens. = 130 g/l surf, area 50 15 mTg pH 3.8-4.5 (4% aq. susp.) > 99.8% assay... 

Chem. Descrip. Micronized PTFE CAS 9002-84-0 EINECS/ELINCS 204-126-9 Uses Lubricant wax, antiblocking agent for inks, paints, and coatings Features Used in combination with micronized waxes and PEs to achieve higher surf, lubricity and antiblocking props. heat resist, and insol. Properties Wh. 5.5-6.5 (mean) particle size fineness (Hegman) 6.0-6.5 sp.gr. 2.2 soffen. pt. > 316 C... 

Chem. Desap. Polyeth ene wax emulsion CAS 9002-88-4 EINECS/ELINCS 200-815-3 Uses Lubricant, antiblocking agent, mar resist, aid, mb resist, aid, water resist, aid for floor finishes lubricanL antiblocking agent, mar resist, aid, mb resist, aid in textiles, leather Regulatory FDA compliance Properties 0.045 p avg. particle size nonionic 35% NV... 

Uses Surf, conditioner, abrasion resist, aid. antiblocking agent for coatings. inks, or overprint varnishes polish resist, in low gloss coatings Features May cause noticeable reduction in gloss Properties 2-3 p avg. particle size fineness (Hegman) 7 sp.gr. 0.89 ... 

The preferred particle size for antiblocking agents is closely related to film thickness, e.g., the mean particle size for antiblocks in LLDPE is roughly 12% of the film thickness. Particle size distributions are usually deliberately narrow, because a few larger particles can cause problems, including haze. Some commercial products have bimodal particle size distributions, or they could contain two antiblocking constituents with different mean sizes. 

A fine-particle silicone additive has been developed by GE Silicones to improve the surface and surface Interaction characteristics of polymers, rubbers and similar materials. A key application for the additive (Tospearl) is an antiblocking agent for thin plastics film. Added to the resin during compounding, the fine particle spheres (0.5 12 pm) protrude from the surface of the blown film to form a uniformly uneven surface that prevents adhesion between film layers. The particle size is selected depending on film thickness. The spherical shape of the particles, combined with good inherent lubricity of silicone, also improves the slip characteristics of the film. 

Antiblock agents (qv) are typically used to prevent adherence, ie blocking, of two film surfaces. They are small particle-size fillers affecting surface smoothness, controlling film-to-film snrface separation distances without greatly affecting clarity. 

The possibility of using silica from rice husk ash as an antiblocking agent in low density poly(ethylene) films has been investigated. Silica from rice husk ash has a smaller particle size and thus a higher specific surface area in comparison to other commercially available silica types (4). 

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