 | Radiation | | Sterilization using either gamma rays or an electron beam to destroy micro-organisms. Radiation sterilization normally takes place in a sealed irradiator unit. |
| Rate of Set | | The time required for an adhesive, under a specific set of conditions to arrive at a fiber tearing bond. |
| Ream | | Five hundred sheets of paper. |
| Recycle | | Ground material from flasit and trimmings which after mixing with a certain amount of virgin material is fed back into the blow mold machine. |
| Register | | The exact corresponding placement of successively printed and/or successively die-cut pressure-sensitive labels. |
| Release | | The force required to remove the release liner from the facestock at a specified speed and angle. |
| Release Coat | | Release lacquer. The release liner treatment material that allows pressure-sensitive labels to release from the release liner. |
| Release Liner | | Backing. Liner lining. The portion of the label that receives the release coating. Prior to application, it protects the adhesive and provides support for the facestock during the die cutting operation and allows the label to be transported to a label applicator or through a computer printer. |
| Release (Mold) | | A substance applied to pressure-sensitive labels so as to prevent sticking when the molded object is removed from the press or mold. |
| Removable Adhesive | | A pressure-sensitive adhesive characterized by low ultimate adhesion to a wide variety of surfaces, that can be removed without damage to either the label or the substrate. |
| Repositioning | | The relamination of labels to a different location on the backing paper following die cutting. |
| Residue | | Adhesive left on a substrate when a label is removed. |
| Resilience | | Capability of a sealer or coating to return to its original size and shape after deformation. |
| Resin | | A general term applied to natural and synthetic polymers, amorphous in structure and without fixed melting point characteristic. |
| Reverse Roll Coating | | The coating is premetered between rolls and then wiped off on the web. The amount of coating is controlled by the metering gap and also by the speed of rotation of the coating roll. |
| Rewind Slit | | A slitting process where a roll of tape is unwound and run through a set of shear or score knives to be slit and then wound up into individual rolls. |
| Rewinder | | A machine which takes rolls from the winder, slits or rewinds into smaller rolls. |
| Rewinding | | The operation of winding the paper from the reel on to a core to produce rolls of the desired width, diameter and tension. |
| Rotary Press | | A printing press using plates formed to fit rolls and using paper in continuous rolls. Newspapers use rotary presses. |
| Rubber Base Adhesive | | A pressure-sensitive adhesive based on natural or synthetic rubbers. |