In-mold labeling in North America
has come a long way over the last 25 years. Once limited to extrusion blow
in-mold labeling (EB-IML) of bottles for liquid consumer products, new
injection molded in-mold labeling (IM-IML) applications are appearing in retail
outlets in increasing numbers. These applications include anything from baby
wipes, spreadable butter, and soft cheeses to prepared salads and ice cream.
Successful development of new IML applications depends
upon close collaboration among end users/brand owners, molders, label printers,
and substrate suppliers. The difficulties inherent in achieving this goal were
the topic discussed at a meeting of industry leaders during the 1994
International In-mold Labeling Conference in Chicago. Those attending the meeting agreed
that a lack of communication along the supply chain often resulted in
unresolved problems and system failures during and after the package
They decided to form an industry organization that
would facilitate communications through commonality of terms and testing
procedures. Led by Ron Schultz, president of RBS Technologies, Inc., they
formed the IML Industry Standards Group. The group’s first undertaking
was a survey of the industry to identify major concerns about the IML process
along the supply chain. Four supply chain links were studied: label raw
materials, label printing and diecutting, blow molding, and the end user. A
statistical analysis of the survey results isolated the top four concerns for
In late 1995, the Group began development of useful
test methods called IML Procedural Guidelines. Up until this time, it was not
uncommon for the printer, blow molder, and end user to each have his own test
method and terminology for measuring attributes of labels and containers. This
often caused a great deal of confusion and miscommunication.
The Guidelines, loosely patterned after ASTM and TAPPI
standards, were offered to the industry as common test procedures that could be
used by all parties, a sort of “neutral ground” approach. The
Guidelines are a “how to” guide to arrive at the actual package and
label specifications set by the customer, usually the end user. They are not
Over the course of several years and a lot of hard
volunteer work, the IML Industry Standards Group developed seventeen IML
Procedural Guidelines as well as a glossary of IML terms. All of them are in
PDF format and are freely available for download from
www.rbstechnologies.com/standards. The following is a brief explanation of the
Temperature: Measures the temperature at which the adhesive
on the back of an in-mold label will become tacky and bond to the container
during the blow molding operation.
Uniformity: Uniformity of the adhesive coating on the back of
the label is an important attribute in defect-free labeled blow molded
Adhesive Coating Weight: Measures the adhesive coating weight
on the back of the label for blow mold applications.
Weight: A standardized technique for measuring the weight of
an in-mold labeled bottle.
of Friction: COF or “slip” is a critical property
that must be controlled for reliable label handling during both the printing operation
and the molding process.
Blocking: Measures the tendency of a stack of labels to stick
together under adverse environmental conditions. Blocked labels will not feed
reliably during molding.
Curl: Measures the tendency of the corners or edges of a
label to curl. Non-flat labels do not feed reliably during the molding
Packaging: Recommendations for proper packaging of in-mold
IML Label Placement: A procedure for measuring the critical
positioning of the label on the container.
Cut Registration: This is a critical label attribute for
reliable feeding from label magazines at the molder.
Registration: This is a method for measuring the tolerance
between colors on a label.
Resistance: A method for determining how well the printed
label resists the product contained in the package.
Resistance: A procedure for measuring the printed
label’s resistance to scuffing.
Retention: This procedure measures the amount of solvents
retained in either the label’s adhesive or print side. Retained solvents
can cause label blocking and affect COF.
Measures the effects of static on the in-mold labeling process.
& Handling Conditions for In-mold Labels: Recommendations
for optimum storage, handling, and shipping conditions for labels in all forms.
Thickness: A standard procedure for measuring the wall
thickness of a bottle.
Although these Procedural
Guidelines were developed for EB-IML, most of them are either directly
applicable or can be adapted for IM-IML. Suggestions or requests for new
Guidelines specific to IM-IML can be forwarded to
Ron Schultz is
president of RBS Technologies, Inc., the organizer of the International In-Mold
Labeling Conference, IMLCON2004, and producer of the ABC's of IML: A Basic
Course (see "Inside the Industry", p. 37). RBS also acts as the
administrator for the IML Industry Standards Group and hosts the Group's
webpage on one of its two web sites: www.rbstechnologies.com or