Q&A: IML-I vs. IML-T
by Roman Artz
2014 IMDA Symposium
- Oct. 22-23
- Doubletree Chicago North Shore Conference Center, Skokie, IL
At the 2013 In-Mold Decorating Association (IMDA) Symposium, held in October in Chicago, IL, workshops were held in which discussions centered on the advantages of injection in-mold labeling (IML-I) and thermoformed in-mold labeling (IML-T). The premise was that containers made by IML-I and IML-T are competing for many of the same packaging applications. In this Q&A, discussion points from the symposium are addressed.
Question: Why is IML-T use limited in North America?
Answer: At the present time, only one molding company in the US has embraced the technology – Tech II, located in Springfield, OH. Yet, it is an IML technology that is showing growth in Europe. Why the disparity in North American adoption?
Many of the larger molders in North America have devoted resources to IML-I and have gone through the maturation process with that process. They may not want to take on the challenge of being ‘first’ with a new – at least to North America – labeling technology. Similar to the development of IML-I in North America, the consensus during the discussion was that the smaller, more entrepreneurial molders would drive IML-T development to begin with and, as it developed, the larger molders would take it on.
Question: In what area does IML-T have an advantage over IML-I?
Answer: In the first session, the IMDA Symposium attendees were fortunate to have Michael Provini, sales manager from Illig LP, USA, provide some insight into the advantages and disadvantages between IML -I and IML-T from his perspective. According to Provini, IML-T is the more ideal technology for thin wall containers and has faster throughput over IML-I for thin wall applications.
Illig has three systems in North America, and each system can output 27,000 parts per hour. The equipment has good "adaptability" and easy change-out for different labels. Tools also can be easily changed. Container size is limited when compared to IML-I, with the largest size for IML-T being the Eurotub. The cost of an IML-T system can run from about $1.3MM to $1.4MM and up, not including the tool.
Question: What are the cycle time comparisons for IML-T vs. IML-I?
Answer: For short production runs, the belief is that IML-I is perhaps better suited than IML-T because set-up is "not as intensive" for IML-I. Like IML-I, IML-T cycle times vary depending upon production factors: i.e., size of part, number of cavities, wall thickness, etc. Incorporating labeling into thermoforming can double the cycle time for IML-T. Commonly, cycle times for injection molding do not increase to that degree when including the labeling process.
Part of the reason for the increase in cycle time for IML-T vs. IML-I comes from the fact that often there is at least one, if not two, additional steps in the transfer process from picking the label out of the label basket to placing the label in the mold for IML-T. This additional step in the transfer process for IML-T can result in a higher degree of variation in label placement. However, improvement in label placement for IML-T is being addressed.
Question: How are label substrates different for IML-T vs. IML-I?
Answer: Because IML-T involves both lower heat and less air pressure in the molding process than IML-I, label substrate requirements are different for the two molding methods.
In order for the label to bond to the part during thermoforming, label substrates for IML-T require a lower melt point. Therefore, issues can arise when the mold temperature is too low, resulting in poor label adhesion to the part, or when temperature is too high, resulting in the label melting.
The use of less air pressure in the thermoforming process than what is employed in injection molding also can present a challenge to the IML-T labeling process. Air often can be trapped between the label and the thermoform plastic sheet, requiring a way to evacuate the air in order to prevent air pockets or "blisters" trapped between the label and the formed part. Substrate suppliers and label converters are both employing different methods to address this issue.
Since label substrates do need to be engineered specifically for the unique requirements for IML-T, and since there is relatively low demand for IML-T labels at this time in North America as compared to label demand for IML-I, IML-T substrates are currently produced only in Europe. Treofan offers a 60micron cavitated PP material that is commercial in both Europe and North America. Taghleef offers a 65micron cavitated material that is commercial in Europe and soon will be commercialized in North America. Both Innovia and Yupo are in development with their IML-T substrate offerings.
Question: Is IML-I or IML-T more suitable for food packaging?
Answer: Discussions then moved to the development of oxygen barrier packaging and whether IML-I or IML-T may be the better solution to address the growing demands for this type of packaging. Label converters and some molders in the sessions voiced their concerns regarding the in-mold label being the functional barrier for barrier IML, since the label would need to maintain 100-percent seaming integrity to be compliant as the barrier. Could this be verified with vision systems? What would be considered a viable scrap rate for non-compliant seams; and who would be liable if non-conforming labeled containers did make it to the retail shelf? These were all brought up as hurdles for IML-I.
On the other hand, since functional barrier properties can be employed more uniformly in the thermoform plastic rolls, the label substrate would not need to be the functional barrier for IML-T. Consensus among the participants was that barrier IML-T may be a more cohesive solution for shelf-stable food packaging.