 | Ultimate Adhesion | | The maximum adhesion available from a pressure-sensitive adhesive, determined by the force necessary to remove a strip of tape from a surface after an extended period of time. |
| Ultimate Strength | | Term used to describe the maximum unit stress a material will withstand when subjected to an applied load in a compression, tension, or shear. |
| Ultra-Violet Letterpress | | An abbreviation describing the process whereby ultra-violet curable inks are printed via the rotary letterpress process. |
| Ultra-Violet Resistance (UV) | | The ability of a material to withstand extended exposure to sunlight (ultra-violet) without degradation, hardening or excessive discoloration. |
| Ultra-Violet (UV) | | Zone of invisible radiations beyond the violet end of the spectrum of visible radiation. |
| Unbleached | | A term applied to paper or pulp which has not been treated with bleaching agents. |
| Unsized | | A term applied to papers to which no sizing has been added. |
| Untrimmed | | Paper cut by slitters with the grain and by rotary cutters across the grain on a sheeting machine. This is less accurate and smooth than guillotine cutting. |
| Unwind | | The force required to remove tape from the roll. |
| Unwind Adhesion | | The force required to remove the tape from the roll under prescribed conditions. |
| Unwind Side | | That side of the tape which is exposed as it is unwound from a roll. |
| UV | | Ultra Violet light. UV is an important factor to consider when choosing an adhesive. UV can degrade some adhesives with extended exposure. |
| UV Stabilizer | | Any chemical compound which, when admixed with a thermoplastic resin, selectively absorbs UV rays. |