Optical properties of adhesive base materials
"EPOL™ Hydroxyl terminated liquid Poly olefin™" is a liquid polyolefin obtained by hydrogenating* "Hydroxyl terminated liquid Poly isoprene™" and has highly reactive hydroxyl groups at the molecular ends.
Since there are almost no double bonds remaining in the molecule, it has high transparency, high resistance to yellowing, and is resistant to discoloration due to heat or ultraviolet rays.
In addition, its low moisture permeability and tackifying properties have led to a growing range of optical applications, including as an optically transparent adhesive (OCA, OCR) for smartphones and other electronic devices, and as an ultraviolet (UV) curing resin compounding agent.
*Hydrogenation: A reduction reaction that adds hydrogen to unsaturated bonds in molecules.
Transmittance at each wavelength
|
R-45HT series cured product |
R-15HT series cured product |
Hydroxyl terminated liquid Poly isoprene™ series Hardened material |
Hydroxyl terminated liquid Poly olefin™ Series Hardened material |
|
|---|---|---|---|---|
| 589nm(D) | 1.514 | 1.513 | 1.517 | 1.476 |
| 486nm(F) | 1.524 | 1.522 | 1.526 | 1.482 |
| 656nm(C) | 1.511 | 1.509 | 1.514 | 1.474 |
| Abbe number | 39.6 | 39.7 | 40.7 | 58.1 |
| Total light transmittance (%) | 89 | 87 | 87 | 90 |
| Yellow Index | 8.3 | 13.8 | 9.0 | 1.9 |
*Each cured product uses isophorone diisocyanate as a curing agent.
Mixing conditions: [NCO]/[OH]=1.05
Curing conditions: Press 120℃ x 1 hour + Post curing 70℃ x 15 hours