Tools & Resources

Frequently Asked Questions

Frequently Asked Questions

Packaging Film

What is compatibility testing?
Compatibility testing is a process that helps to determine if a material is resistant to chemical degradation or physical change caused by the product.

Why is product/package compatibility testing strongly suggested for products without a known history in a flexible packaging structure?
Product/package compatibility testing is a screening process to determine if a given product might have any adverse effects on the packaging structure. The most common adverse effect is a reduction in the adhesion levels between the layers of the structure. The reduction in adhesion levels can range from slightly noticeable to full delamination. The more severe the interlayer adhesion level reduction, the more difficult it will be to tear open the package and the lower the package burst strength will be. The product/packaging compatibility testing will help to determine the most cost effective structure for the product.

How much product is needed for testing?
We request that you send between 20 and 32 ounces of product.

I have a new product similar to one already in the marketplace. I would like to know what flexible packaging structure is being used to package the existing product in an effort to identify a potential structure for my product’s packaging. Can Glenroy help me with this?
Yes, Glenroy’s packaging engineers can reverse engineer a supplied package and offer a structure suggestion based on the results. This is referred to as “material breakdown analysis” or “analysis of construction.” This process takes approximately one week from receipt of a sample.

Can Glenroy recommend a specific film lamination suitable for any given project?
Glenroy offers many services that will help assist your organization in understanding materials that are fit for use. Glenroy can provide suggestions and product/package stability testing, but it is up to each product manufacturer to understand how their product acts over time in a specific type of packaging.

What is Barex?
Barex is an impact modified acrylonitrile copolymer sealant film.

When would I want to consider using Barex?
Barex is an excellent barrier to a wide range of chemicals that would otherwise cause interlayer delamination in structures using polyethylene type sealant films. Barex also protects product integrity by preventing the migration of flavors, fragrances and active ingredients out of the product into the packaging structure.

What is Surlyn?
Surlyn is a specialty sealant resin made from ethylene acid copolymer.

When would I want to consider using Surlyn?
Surlyn is known for its high hot tack strength, wide range of sealability and ability to seal through contaminates, such as powders. Surlyn also provides an excellent barrier for oily or greasy products.

What is EAA and how is it different from EMA or EMAA?
EAA (Ethylene acrylic acid) is a copolymer of ethylene and acrylic acid monomers EMA (ethylene methyl acrylate) & EMAA (ethylene methacrylic acid) do not bond as well to aluminum foil.

What is LLDPE and how does it differ from LDPE?
LLDPE stands for linear low-density polyethylene and is a substantially linear polymer (polyethylene). LLDPE has higher tensile strength and higher impact and puncture resistance than LDPE. It is very flexible and elongates under stress. It can be used to make thinner films, with better environmental stress cracking resistance. It has good resistance to chemicals and to ultraviolet radiation.

What is MVTR and OTR?
MVTR stands for moisture vapor transmission rate, or the rate at which water vapor passes through a substance. OTR is Oxygen Transmission Rate, or the rate at which oxygen passes through a substance.

What are typical thicknesses for sealants when packaging mailer?
Typically customers choose sealant films in the 3.0 mil mm range when packaging for a mailer. However, please note, not all sealant films perform the same at this thicker gauge.

What are typical thicknesses for sealants when packaging samples that will be distributed in mailers?
Typically customers choose sealant films in the 2.0 mil mm range when packaging for a mailer.

Does Glenroy offer any child-resistant packaging?
Glenroy does provide material used in child resistant applications. We can offer a material suggestion based upon the application and final usage. The only way to deem a structure child resistant is to have child-resistant protocol testing performed, which is the responsibility of the end user of the packaging material. (This applies regardless of the structure Glenroy might suggest).

What is MI?
MI stands for Thousand Impressions.

What is MSI?
MSI stands for Thousand Square Inches.

What is the difference between extrusion coating and adhesive coating?
Extrusion coating is the coating of a molten web of synthetic resin on to a substrate material. The actual process of extrusion coating involves extruding resin from a slot die at temperatures up to 610°F/320°C directly onto the moving web which is then passed through a nip consisting of a rubber covered pressure roller and a chrome plated cooling roll. The latter cools the molten film back into the solid state and also imparts the desired finish to the plastic surface. Adhesive coating is the coating of an adhesive (a mixture in a liquid or semi-liquid state that adheres or bonds items together) to a substrate material.

What is reverse printing?
Reverse printing is the process of printing on the back side of a clear substrate, sometimes referred to as subsurface printing, with a reverse image. In the process of manufacturing flexible packaging the print will be buried between the outside substrate and the rest of the structure, offering scuff and chemical resistance. When the outer substrate is mounted to the remainder of the structure, it will be right reading.

What is the difference between flexographic printing and rotogravure printing?
Flexographic printing is the method of printing on a web press using rubber or photopolymer plates with raised images. Rotogravure printing does not use plates, rather the image is etched directly onto a cylinder. It can be distinguished when looking through a loupe - it has teeth like marks around type and solids.

What kind of ink systems does Glenroy use?
Glenroy uses solvent based, pigment inks.

What is ink viscosity?
Viscosity describes a fluids resistance to flow. In everyday terms, viscosity is the thickness. A liquid with a low viscosity, such as water, would be considered thin. A liquid with a high viscosity, such as honey, would be considered thick. Ink viscosity refers to this resistance of the ink.

How do I submit a graphic file?
You can mail your art on a compact disk to Glenroy, Inc., W158 N9332 Nor-X-Way, Ave., Menomonee Falls, WI 53051 - Please label disks with company name, contact, project name, and date.

You can send it via e-mail to -We recommend compressing the files (with StuffIt, ZipIt) prior to sending. When sending a file via e-mail, please include an Adobe Acrobat PDF file in lieu of a hard copy proof.

We can retrieve art posted to an FTP site. Please e-mail appropriate information (address, user name, password) and include a PDF file.

We will also be offering a fast and convenient way to upload graphics to our FTP server through our website in the near future. More information will be posted soon.

Where can I find Glenroy’s graphic specifications?
Our Graphic Specification can be found here

What is a press approval?
A press approval is the process of being onsite during the printing phase of the manufacturing process for a specific item. A press approval allows you to approve colors and the overall look of the item as its being printed.

How do I arrange a press approval?
At the beginning stages of your project, contact your Glenroy representative to arrange a press approval.

What is a plate break?
A plate break is a non-print area where the two ends of flexographic plate butt together after being wrapped around the plate cylinder on the printing press.

What is a cover plate?
A cover plate is a designed to print a solid color to cover a plate break. The cover plate will be wider than the plate break to ensure it completely covers the plate break. This results in a double hit of color on each side of the plate break.

What is an eyespot and an eyespot tracking path (or channel)?
An eyespot is a small rectangular printed area (usually of contrasting color to the background) located near the edge of a web or design. The eyespot reader is triggered by the eyespot as the web passes by, to control register of the printed design with subsequent form, fill or seal equipment or operations.

An eyespot tracking path (or channel) is a pathway between the eyespots that the eyespot reader is tracking. Generally this pathway should be clear of obstructing design or text.

What is the difference between extrusion coating and extrusion lamination?
Extrusion coating is the coating of a molten web of synthetic resin on to a substrate material. Extrusion lamination uses a similar process except that the extruded hot molten resin acts as the bonding medium to a second web of material.

What is the difference between mono-extrusion and co-extrusion?
Mono-extrusion is the extrusion of a single resin where co-extrusion is the simultaneous extrusion of two or more different resins into a sandwich-like film with clearly distinguishable individual layers.

What is converting?
Converting is simply changing something into a different form. In the case of flexible packaging, converting would be the process of utilizing films, foils and resins and through the process of lamination, form them into a multi layer structure.

What information is needed to enter an order with Glenroy?
Once a credit application has been approved, the four categories of information needed are:

  • Purchase Order: Includes information on quantity, item identification, requested delivery date, shipping location, invoicing location, special instructions, etc.
  • Artwork: File for artwork, PMS colors or samples of specific color matches, and contact information.
  • Layout: Front and back copy orientation, graphic position, eyespot location, size, etc.
  • Specification: Material structure, roll dimensions, etc…
  • For a full checklist of information needed to place an order, please click here.

What is flexible packaging?
Flexible Packaging is non-rigid packaging structures used to package and protect various food and nonfood products in the retail and industrial business forum. Snacks and frozen foods, medical appliances, beverages, pet food, etc., are a sampling of products packaged in this medium.

Does Glenroy offer onsite educational presentations about flexible packaging?
Yes, Glenroy would be happy to offer our customers onsite presentations to help educate others about flexible packaging as well as our manufacturing process and technical capabilities.

What are Glenroy’s typical lead times for packaging film?
Glenroy works hard to get materials to you when you need them. Let your Account Manager know your timelines, so we can work with you. Generally, on new orders, lead times are 4-6 weeks and on repeat orders 2-4 weeks. Raw material availability may add to these time frames.

Do you form and fill packages?
No, we supply rollstock and premade pouches, which are formed, filled, and sealed by contract packaging companies or by manufacturers with packaging equipment. Glenroy works with an extensive network of contract packaging companies and can refer you to a contract packaging company if you need forming, filling, and sealing capabilities.

What information do I need to get a quote?
Generally, in order for us to provide a quote we’ll need the specifications of the item along with your company and contact information. The item/project name along with structure, web width & quantities are all necessary. If the item will be printed at Glenroy, we’ll also need the cut-off, package size and the number of colors in the art. Other helpful information would be the type of filling equipment that will be utilized, the type of product and ingredients list and the method of distribution (mailer, magazine or handout).

Surface Printable Packaging Film

What are Glenroy’s standard film widths?
Glenroy’s stock narrow web films are carried in 40", 45" & 52" widths, which can be slit to accommodate the needs of an application.

Balloon Film

Does Glenroy manufacture mylar (metalized film) balloons?
No, Glenroy manufactures the rollstock that is supplied to balloon manufacturers for the forming and sealing, packaging, and distribution process.