Molding Powder

molding powder

[′mōl·diŋ ‚pau̇d·ər]
(materials)
Powdered plastic-material ingredients (such as resin, filler, pigments, and plasticizers) ready for compression in molding.

Molding Powder

 

a powder or granulated material intended for processing into products by molding.

Molding powders are thermosets, which are a partially hardened mixture of 30–60 percent thermosetting resin (most often a phenol-aldehyde resin) and 40–70 percent finely divided filler (for example, sawdust, silica flour, ground mica, or short-fiber asbestos). They may also contain (by weight) 1.5–3 percent lubricants, such as stearates of calcium or zinc or a mixture of stearic and palmitic acids, and 2–4 percent coloring agent, usually ni-grosine, which imparts a black color to the powders.

The production of molding powders includes the sequential operations of preparation and mixing of the components, preliminary hardening, and particle size reduction or granulation. To achieve improved wetting and better impregnation of the filler by the thermosetting resin, the resin is frequently used in the form of a solution or emulsion. The basic characteristics of molding powders are the specific volume, granulometric composition, pouring properties, fluidity, useful life (the length of time over which processing properties are preserved after the addition of the hardener), rate of hardening, and shrinkage.

A. R. BEL’NIK

molding plastic

A partially polymerized resin, usually in powdered form, which is molded under heat and pressure; often filler materials and pigments are added.
References in periodicals archive ?
ClickPress, Tue Jul 28 2015] North America Melamine Formaldehyde Market by Application (Laminates, Molding Powder, Adhesive, Coating), By Country (U.
Fluon filled PTFE compounds and melt processable compounds, composed of pigments and fillers such as glass, carbon, graphite and metal powders, are molding powders that are said to enhance wear resistance, creep resistance, thermal conductivity and electrical conductivity over virgin TPFE resins.
Simpson et al used a sol-gel method to cast these materials to near-net shape or form homogeneous molding powders.
The major end-use segments analyzed are Acrylic Plastics & Resins (Cast & Extruded Sheets, and Molding Powders & Resins).
The SMC, BMC/DMC report also covers the market for molding powders, which despite not being reinforced with glass fibers, are very similar to SMC/BMC in processing terms.
When used in amounts from 1% to 3%, they act as processing aids, absorb excess plasticizer, prevent caking of molding powders and plate-out, and promote printing-ink acceptance.
Processing aids, when used in amounts from 1% to 3%, they absorb excess plasticizer, prevent caking of molding powders and plate-out, and promote printing-ink acceptance.
Phenolic antioxidants include Santonox and Santonox R for use in PE and other plastics; and Santowhite Powder for PP, PE, nylon molding powders, and other polymers.
These pigments neither affect nor are affected by the usual polymerization catalysts or exotherms and are generally recommended for acrylics, both casting syrups and molding powders, nylons, polycarbonates, epoxies, urethanes, polyesters, PE, PP, both plastisol and extrusion vinyl, ABS, and PS.
Used in amounts from under 1% to 3%, they are processing aids that absorb excess plasticizer, prevent caking of molding powders and plate-out, and promote printing ink acceptance.
Phenolic antioxidants include Santonox and Santonox R, used in PE and other plastics; and Santowhite Powder for PP, PE, nylon molding powders, and other polymers.