Liquid additives have been typically supplied in blends with liquid colors, but Riverdale Global, Aston, Penn., has expanded its “never-see-a-drop” total system for liquid colors, to a full range of modifiers and process aids. Each is supplied as a single additive dispersion in a container that stays sealed from the moment it arrives at a plastic processor’s loading dock, through storage, handling, and metering into the process, and during return to Riverdale Global for replenishment.
The new GlobalPlus sealed additive system is designed for processors who run clear or natural resins or who need to supplement the additive package in pre-compounded or masterbatch materials. (Riverdale Global also now supplies sealed additives to its own satellite operations in the U.S. and overseas, where they can be blended with single–pigment dispersions for custom color-matched formulations.)
Here’s how it all works: Using the company’s proprietary “Pump in a Drum” design, the additive is metered into the process by a pump that is located inside the drum. Riverdale’s total system eliminates the complications of handling liquids, including spillage, leakage, cleanup, pump maintenance, unused additive, environmental concerns, and disposal costs, according to v.p. of process technologies Kevin Cabana. While liquid additives typically cost more per pound than pellet concentrates, they contain higher active ingredient loadings, are used at lower additive levels, and take up much less warehouse space. Because liquid additives by their nature disperse more readily, letdowns of 0.1 to 1.5% are typical vs. letdowns for concentrates that can range from 0.5 to 4.0%. Riverdale Global’s sealed additive product range includes:
• +Glide slip agents, including silicone, fatty acid ester, stearate amide, and fatty amide types, plus formulations that function as both lubricant and antistat.
• +Foam blowing agents, including azodicarbonamide and endothermic chemical blowing agents as well as combined formulations.
• +Shield UV light stabilizers, including hindered amine (HALS) and UV absorber types for both polyolefin and PET resins.
• +Speed nucleating agents, including clarifiers for polyolefins and nucleating agents for polyolefins, PET, and nylon.
• +Zero antistatic agents for use with polyolefins, styrenics, PVC, and some engineering plastics.
• +Guard antioxidants for polyolefins and styrenics that prevent oxidation in uses involving high levels of heat exposure or multiple heat histories such as those encountered in recycling.
• +Clean antimicrobials for protecting products from bacterial or mold.
• +Gains flow modifiers for enhancing material flow during processing and also for saving energy.