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Q3 Permeation Products & Services Newsletter

Wednesday, September 25, 2024


 
 

Quarter 3 | September 2024

 
 

Material Type (mono w/coatings)

Coatings have been utilized to improve oxygen and water vapor barrier performance of packaging materials for many years. With increased focus on sustainable packaging, coatings are incorporated into “barrier mono-material” compostable and paper/fiber packaging structures. Characterizing coatings for barrier performance is commonly performed in a variety of ways:

Coating Only:

  • For a "Coating Only" test, some coatings can be cured on a “slippery” surface, where it will have poor adherence. Materials like Teflon® or silicone are sometime used for this purpose. In these cases, the coating can be delaminated and tested by itself as a film.
  • Calculating "Coating Only" performance. By initially measuring the transmission rate (TR) of the polymer substrate and then a substrate with the coating applied, the coating’s barrier performance can be calculated via the resistance equation:
    •  
      o 1/TRcoating = 1/TR(substrate+coating) - 1/TRsubstrate
      o Note: If the polymer substrate is also a relative barrier for OTR or WVTR, a higher transmission rate surrogate substrate could be utilized.

For the newest niche of recyclable “mono-material” barrier films (polymers with primers, coatings and adhesive layers), typically the focus is on the entire material structure (and not specifically the coating). As such, the stacked film/primer/coating/adhesive/film material is analyzed via standard OTR and WVTR test methods for barrier performance.

Correct analysis techniques are important. Coatings applied to paper/fiber substrates can be a challenge to analyze, if the coverage isn’t uniform. With non-uniform coverage, a coated porous substrate could continue to have small pin holes and channels throughout the coating surface.

  • A traditional ASTM F1249 test (with flowing gasses) could yield erroneous data for a sample with pinholes. Until the coating coverage can be approved, a gravimetric ASTM E96 is often more appropriate.
  • Likewise, a traditional ASTM D3985 / F1927 OTR test can yield erroneous data for a porous sample. For these film structures, an accumulation method ASTM F3136 is more appropriate, until the coating coverage is improved.

Lastly, test conditions can play a huge role in the performance of coatings to transmission rate. Humidity reacts with some substrates (see our 2024 Q1 Newsletter) and coatings, which impacts the overall OTR or WVTR. Overall, there are many items to consider when characterizing coatings.

 

Coming Soon: NEW ASTM E96 Instrument

AMETEK MOCON is proud to introduce our new PERMATRAN-G gravimetric permeation analyzer. This new instrument complements our other WVTR permeation analyzers to provide automated reliable water vapor permeation measurements following the popular ASTM E96 standard. By testing with either wet-cup, dry-cup or inverted-cup methods, it is a versatile instrument for a wide detection range from 0.1 to 10,000 g/m2*day.




Available in two different versions of either 9 cups or 12 cups, the instrument can support a large amount of testing. The easy loading system incorporates an environmentally controlled chamber for precise temperature and humidity test conditions. The touchscreen operator interface is easy to use and has a display with all the testing data. The automated testing system removes a lot of variability compared to a typical manual E96 testing approach. This improves the accuracy and repeatability of testing results to help customers make better decisions.

The new PERMATRAN-G series provides a testing range that is in between our PEMATRAN-W 101K and our PERMATRAN-W 3/34 series.

To learn more about MOCON ASTM E96 testing solutions, please visit our website:

Learn More


Large Capture Vessel for Whole Package Testing


Often, package permeation testing is focused on what is entering the system (i.e. ingress). There are many applications that require one to understand what leaves a packaging system (i.e. egress). Common permeation egress testing is looking for moisture and oxygen. Examples of moisture egress testing are drug delivery systems (e.g. syringes) or filled saline bags. Examples of oxygen egress are inflated products such as sports balls.

 

Historically, these have been measured by placing samples within a hermetically sealed system that allows purging of the volume, which routes the egress gas to a detector. This system often consisted of a glass jar or metal cup that enclosed the sample by securing it to a brass plate with epoxy. The plate had holes drilled to accommodate purge lines.

 

The traditional whole package egress setup presented challenges in repeatability, especially for high-barrier packages. This was due to needing an accurate leak rate of the empty vessel to subtract from the sample value. Since epoxy may not always cure the same, this potentially causes seal inconsistencies between the leak rate and sample tests.

 


AMETEK MOCON has designed cartridges that consistently seal the same, thus increasing high-barrier whole package repeatability. These systems contain gaskets specific to either oxygen or moisture, increasing seal robustness. They are available in four different sizes to accommodate a multitude of samples, and can be tested on both our package and film permeation analyzers.

Literature

Revised or new application notes (click images below).

Curious for more? Uncover a wealth of knowledge on similar topics and industries in our Resource Library linked below:

Resource Library
Events

We're three-quarters of the way through our 2024 trade show season! Check the remaining dates below to see if we're coming to a location near you:

Coming in spring 2025 is our 17th Permeation Conference! Hosted by AMETEK MOCON. Next year's conference will take place in the countryside near Höhr-Grenzhausen, Germany. To learn more about the conference, please visit the link below:
Read More

For customers located in the United States, we'll be at:
Pack Expo International 2024
  • Location: Chicago, IL
  • Days: Sunday, Nov. 3 - Wednesday, Nov. 6, 2024
  • Booth Number: W-17080
For customers located in Europe, we'll be at:
Multilayer Packaging Conference
  • Location: Vienna, Austria
  • Days: Tuesday, Dec. 10 - Wednesday, Dec. 11, 2024
  • Booth Number: (TBD)
Currently, we have no shows scheduled in Asia for the rest of 2024.

Our list of 2024 trade shows and events is now final. Check the link below to our events page to see where we will be!

Events