Page 277 - Engineering Plastics Handbook

Chapter
11

Liquid Crystal Polymer (LCP)

Toshihide Inoue
Toru Yamanaka
Yoshiki Makabe
Chemicals Research Laboratories,
Toray Industries, Inc.,
Nagoya, Japan

Introduction
Polyester-based liquid crystal polymer (LCP) is one of the most attractive
materials in the field of engineering thermoplastics because of its supe-
rior heat resistance, stiffness, accuracy of dimensions, moldability, and
excellent balance of these properties. LCP is recently expanding its appli-
cations, in particular, those for the precision electronic parts appropriate
for surface mount technology (SMT). The historical perspective of LCP is
outlined below.
In 1972, Cottis and coworkers at Carborundum patented wholly aro-
matic polyesters based on p-hydroxybenzoic acid (HBA), 4,4′-dihydrox-
ybiphenyl (DHB), and terephthalic acid (TPA), one of which was later
®
commercialized as EKKCEL I-2000 [1]. In 1974, Kuhfuss and cowork-
ers at Eastman Kodak reported a new polyester based on HBA and
poly(ethylene terephthalate) (PET), which was later marketed under the
code of X-7G. X-7G is the first thermotropic liquid crystalline polymer
to be fabricated by injection molding or melt spinning [2]. However,
then Eastman Kodak withdrew its plan of marketing of X-7G and
changed the target with a wholly aromatic polyester commercialized as
® ®
TITAN (THERMX ) in 1996. As described later, it was acquired by
DuPont in 2003.

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