Coating - Aimcal

Executive Summaries • A Look Ahead
extrusion Laminating
& Film Making
The basic extrusion laminating and coating technologies
as we know them today began in earnest after the end
of WWII and have continued to grow in capability and
complexity in the years since. In the mid- to late-1980s,
laminating capability for snack packaging with high bond
strength was related to a basic capability of 100 mpm
(330 fpm) speed with an 18-cm (7-in.) melt drop using
LDPE at about 315 deg C (600 deg F). Today, you can
purchase machines, which operate at high speed and
material efficiencies while depositing multilayer coatings
of five or more layers, if desired, to add improved barrier,
optical or physical properties. The same improvements
also are available for film manufacture ranging from cast,
blown and oriented films for use with or to compete with
the extrusion coater and extrusion laminator. In many
cases, you are limited only by your imagination and
pocketbook.
The sources of the dramatic improvements in capability
have been both evolutionary and revolutionary, and the
knowledge gained about what makes a functional product
is still controlling the final properties and attributes of the
products made today. Primary areas of advancement
have been in new resins, die design and coextrusion
technologies, digital drives and the integration of multiple
components and improved control methods. This has
allowed existing product designs to be improved in both
quality and productivity. At the same time, advances in
basic machine components — such as screw designs
and the extruder, die and coextrusion capabilities
— all combine together to allow further productivity
improvements and capabilities not possible from a single
improvement.
The availability of a widening range of new copolymers,
tie resins, barrier and reinvented “old” resins has been
driven by advances in polymerization research and
catalyst technologies. These material advances have
made the use of coextrusion widespread and extremely
102 | 2012 AIMCAL SourceBook
effective in product-property enhancements. Three-layer
extrusion coatings and laminating layers using various
copolymer-skin resins now allow the uncoupling of line
speed and bond-strength development by reducing the
impact of melt oxidation on bonding. Better and new
surface-oxidation control of the melt is still possible in
the future and is constantly being reinvented to improve
bonding and, in combination with coextrusion, should
allow further improvements in productivity down the road.
The addition of barrier properties to the extrusion coating
or laminating layer has kept pace with comparable
advances in film extrusion. Five-layer barrier coatings
and lamination layers are common, and nine- and higherlayer
counts in packaging films readily are available
from suppliers. new micro- or nano-layer coextrusion
capabilities are now generally available and, combined
with resin availability, will make significant and important
improvements in film physical properties. The new
coextrusion capabilities of splitting barrier-polymer layers
permit further barrier improvements over single layers of
the barrier polymers. Edge encapsulation (side-by-side
coextrusion) also has improved scrap utilization and
reduced neck-in for both film and extrusion coating.
Continued growth and improvement in all of these areas
should fuel further growth and advancements in product
quality, performance and completion between film and
lamination technologies and should extend these products
into the new and evolving technologies we use in our
everyday lives, from packaging and window films to solar
cells and OLED TV screens. n
By eldridge M. Mount, Ph.D., president, eMMount
technologies, 585-223-3996, email: emmount@
earthlink.net, www.emmount-technologies.com