Progress on Rotomolding Materials
& Manufacturing
23rd November 2004
Toronto, Ontario
Sponsored by
The Ontario Roto-Moulding Working Group
McMaster Manufacturing Research Institute,
Centre for Advanced Polymer Processing and Design CAPPA-D
Materials and Manufacturing Ontario (MMO) - A
Division of Ontario Centres of Excellence Inc. (OCE Inc.)
This turned out to be a much better attended
event than I expected. Over 80 people turned out to hear some excellent
presentations on various aspects of the process. Elizabeth Takacs of McMaster University
and Ross Bradsen of Materials and Manufacturing Ontario combined an academic
outreach to molders in the region with government support that is an interesting
model that other areas might benefit from. The MMO apparently has a considerable
pool of funds available for a wide range of research projects - they have
supported some 2400 projects in recent years. Their joint goal is to promote
interaction between the agencies to support market and technical development at
molders. There were about 11 molders in attendance (more next time please!)
along with quite a few designers, which actually made a pleasant change.
A packed house in Toronto - Einar Voldner (front right) didn't
have too far to travel for this one.
Introduction to
Rotational Molding & Specialty Polymers for Rotational Molding, Einar
Voldner, Synergy Polymers Inc.
Einar set the scene for the group with a discussion on the
basic operations of rotomolding with videos inside molds and a review of the
range of materials that are both commonly used and those that are being tested
or have been tried in recent times. Einar sees metallocene materials as being
the dominant group in polyethylene within the next 5 years and within 10 years
sees the emergence of nano-composite materials.
New Polyolefins for
Rotational Molding, Dr.
Eric Maziers, Total Petrochemicals, Ron Partridge, Arkema
There have been some changes at Atofina - Eric
now works for Total in Europe and Atofina in North America has now been
renamed as Arkema. Whatever the names, they still supply some very interesting
high performance materials.
Total's new polyethylene materials have a
self-nucleating nature with smaller crystal structures that allows for better
processability and better mechanical properties. These new single site
materials apparently have better surface gloss, improved permeation resistance
and better adhesion to other polymers such as nylon.
Their new polypropylene materials reportedly
have reasonable impact performance even at -20°C.
Ron Partridge of Arkema discussed the use of
their nylon and polyethylene materials in a dual layer combination for fuel
tanks. This produced excellent bond strength and permeation levels well below
the new standards. The parts produced typically use drop-boxes or manual drop
but he suggested that one-shot systems may be possible.... Fast cooling
improves impact performance and shrinkage problems - he provided some useful
Rotolog data to guide molders on how to control the molding cycle.
Some dual layer products displayed by Total / Arkema included
PE/Nylon tanks and PE/PP containers. The PP layer on the red part was almost
transparent.
CBT® Resin - An
Engineering Thermoplastic for Rotational Molding for New Applications, Dr. Jing Wang, Cyclics Corp.
Dr. Wang presented information on the new range
of CBT® resins
that Cyclics Corp. have developed for rotomolding. These offer excellent
performance characteristics and offer some very interesting surface finish
effects. Since the material becomes a liquid shortly after the heating cycle
begins, it can be loaded with glass fibers and other fillers at quite high
loadings. He gave a very thorough review of the properties and processing
requirements for the materials. Cyclics Corp. expect 500MM lbs of materials to
come on stream early in 2005.
Expandable Polymer
Microspheres for Weight Reduction, Chris Rosenbusch, Expancel Inc.,
David D’Agostino, formerly McMaster University
Chris and David presented information on the
use of expandable microspheres for creating foamed cross-sections in
rotomolded parts. These are small (30µm) plastic shells filled with liquid
hydrocarbons that expand (120µm) to 'foam' the surrounding material. They
have been used in printing and other processes for many years and can be dry
blended with rotomolding powders for easy processing. However, they are
relatively expensive at the loadings required compared to standard foaming
compounds and also reduce part performance in some ways. David presented data
showing that elongation improved on a volumetric basis instead of showing the
actual declining data for the samples (a little unfair to present it this way
for the average attendee).
Acetal Copolymers
for Rotational Molding, Alan Dubin & Duane Emerson, Ticona
Alan and Duane reviewed the moldability and
performance characteristics of their new acetal grades. The material cost is
relatively low compared to other engineering resins (3x polyethylene) and it
has some excellent physical properties. They have apparently been working on
molding trials with 3ft diameter pipe products which are 20ft long with some
success. It has higher temperature resistance than polyethylene and good
permeability. They have been working hard on dual layer systems for the recent
tank standards coming out of California but announced that they may have a
single layer version available - early tests have looked promising. They also
have some other interesting materials including PPS and polyester alloys.
Unfortunately, Duane just kept talking and talking and held everyone back from
their coffee break....
Rotomolding with
Vinyl Compounds, Ladd
J. Horvath, Polymer Services & Innovations
Ladd gave a nice presentation on the use of
vinyl materials, both liquid and powder. These are used extensively in a wide
range of industries including may automotive components.
Rotomolding Markets
and Materials around the World, Dr.
Paul Nugent,
Yours truly with a review of markets, products
and various material developments around the globe.
Marketing
Strategies, Gary
Svoboda, Adventus Research
Gary closed out the day with a discussion on
some of the best approaches for marketing.
