Journal of Photopolymer Science and Technology
Online ISSN : 1349-6336
Print ISSN : 0914-9244
ISSN-L : 0914-9244
Strategy for Improvement of Non-flammability in Functional Polyimides
Junichi IshiiHideyuki YokotsukaTakayuki SaitoMasatoshi Hasegawa
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2011 Volume 24 Issue 3 Pages 287-291


A phosphorus (P)-containing diamine was synthesized and used as a comonomer at a minor fraction to improve insufficient non-flammability of a poly(ester imide) system as a promising candidate of base film materials in flexible printed circuit boards (FPC). The P-modified PEsI copolymer film displayed the highest level of non-flammability (UL-94, V-0) comparable to commercially available conventional aromatic PI films in addition to original excellent properties, i.e., a very high Tg, a low linear coefficient of thermal expansion (15.7 ppm/K) close to copper foils, a low water absorption (0.54 %), a low linear coefficient of humidity expansion (5.53 ppm/RH%), and sufficient toughness (elongation at break = ca. 40%). This approach was also attempted for a very flammable low-modulus PI system for aiming at an application as a coating-type cover layer material in FPC.

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© 2011 The Society of Photopolymer Science and Technology (SPST)
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