R
Reinforcing agent
Additive that increases the mechanical properties of thermoplastic and
thermoset materials. Typical reinforcing agent include glass fibers, carbon
fibers, and aramid fibers.
Release agent
Additive that imparts adhesives with extremely low surface energy and
anti-stick (release) properties (silicones, fluorine derivatives, ...). Helps
significantly the release of parts.
Resin
Base for adhesives. Solid, semi-solid or pseudo-solid organic material which
has an indefinite and often high molecular weight. Exhibits a tendency to flow
when subject to stress.
Resorcinol / Phenol-Resorcinol Formaldehyde, PRF
(extended definition)
Type of phenolic resin, but
will cure at room, as well as, with the elevated temperatures.
Rheology modifier
Substance used to raise or control the viscosity without the necessity for
major changes in the total solids content. Organic or inorganic, generally
considered as being either pseudoplastic or thixotropic in nature.
Syn. Thickener
Rosin
Solid resin obtained from pine trees, consisting essentially of abietic acid, a
tricyclic carboxylic acid, and varwious isomers. Frequently used as a flux
component, usually with additives. Also used as a component in tape adhesives,
rendering contamination from them difficult to remove.
Room Temperature Vulcanizing (RTV)
The tendency of an RTV adhesive to vulcanize
(or cure
) at room temperature. Changes from a liquid/paste state to a solid, flexible
rubber. Example: Silicones
Rubber
Crosslinked or vulcanized material that is capable of recovering from large
deformations quickly and forcibly, and can be modified to a state in which it
is essentially insoluble in boiling solvent, such as benzene, methyl ethyl
ketone or ethanoltoluene azeotrope. See
Natural Rubber, NR
Reclaimed Rubber (extended
definition)
Product resulting from the treatment of vulcanized scrap
rubber in various operations, such as grinding, defibering and devulcanizing by
heating with aqueous alkali or with a metallic chloride solution and reclaiming
agents.
