POLYETHYLENE 101 “Flexographic Printing”

Bold, Sharp, Eye-catching Packaging with Flexographic Printing

In this day and age high-end printing and eye-catching graphics are a necessity in the packaging industry in order to have a competitive edge and produce brand recognition with customers. Ever wonder how your package is printed with such accuracy to present that “wow” factor? The form of printing is referred to as Flexographic Printing, a modern day form of printing that can be used on many substrates including Polyethylene film.

The process of Flexographic printing using safe inks was approved by the Food and Drug Administration in 1949 and requires a three-step process of platemaking, mounting, and printing.

  • Platemaking can occur in three methods, the first of which is plate development using light-sensitive polymer. The second method uses a computer guided laser to etch the image onto the printing plate. And the third method requires that the plate goes through a molding process.
  • Mounting is a process used to ensure an accurate picture image. For each color to be printed, a plate is made and eventually put on a cylinder, which is placed in the printing press. Mounting marks are put on flexographic plates to help with precise alignment on the cylinder. These marks are key to aligning each color in the printing press. Equipment is extremely important at this point in the process as highly accurate and specific machinery is made for mounting these plates on the printing cylinders.
  • Printing is the final process in flexographic printing and produces the end result of a sharp looking package. The process requires that a positive mirrored master of the required image is created as a 3D relief in a rubber or polymer material. The image areas are raised above the non-image areas on the rubber or polymer plate and ink is transferred from the ink roll to the anilox roll where excess ink is removed before inking the printing plate. The polyethylene film is finally pressed between the plate and the impression cylinder to transfer the image.

Next time you’re admiring your bold printing and graphics on your polyethylene package or looking for a new and improved look for your package, remember that flexographic printing can achieve the best results. This complex printing process is the key to producing a polyethylene package that your customers will continue to recognize!


How Polyethylene film is made

The process for making polyethylene film and bags is called extrusion. This process starts with melting down small plastic pellets, ( called resin ), until they become molten and pliable.



The molten plastic is pushed, ( extruded ), through a circular die to form a continuous tube of plastic called the bubble. The bubble is inflated with air to the desired diameter and drawn vertically up a tower giving it time to cool before it is flattened to its lay flat width. The thickness of the film is controlled by the speed at which it is pulled from the die. The width of the film is controlled by the amount of air inserted in the bubble.



Film color can be changed in the molten process by adding resin pellets that contain colored pigment.

Many things can be done during this “inline” process. A printing press may be printing images, instructions, warnings, company logos, ect.. on the film. A bag making machine can seal and perforate the film to form varying lengths of bags on rolls. The film can be cut and separated for individually cut bags. You can also add vent holes, which are punched through the film in a variety of patterns and sizes.

The inline process has some further processing limitations. If the film requires more technical alterations then rolled film will be taken off the extrusion line to be further modified in what is known as out of line converting. Here is where you see Process printing and laminating, in addition to process of making sideweld bags, reclosable bags, and wicketed bags, is done out of line.

Blown Film LIne

Tri-Cor Improves its Image with HubSpot®, Kuno Creative, & Fahoury Ink

Tri-Cor Flexible Packaging has joined forces with a great team of experts to improve the company’s image and bring the polyethylene packaging industry to the web world.


With HubSpot’s® and Kuno Creative’s inbound marketing and custom website design expertise, as well as Fahoury Ink’s copywriting and online messaging proficiency, Tri-Cor aims to broaden our range and reach more customers on the internet.

Tri-Cor understands that today’s world revolves around the internet and therefore has set out to create a website that is easier for our customers to find the products they are looking for. Our new website, which you can expect to see hit the web in the next month or two, will be featuring a full product line to satisfy our customers and improve our inbound marketing.

What is inbound marketing?

Inbound marketing is a marketing strategy designed to build a relationship between our product (polyethylene packaging) and our customers (you!).

What can you expect from Tri-Cor’s new website design?

The site will contain valuable content consisting of detailed descriptions of all our products, sharp product pictures, depictions of the markets we serve, quote request forms, blog postings to keep you informed, links to our social media pages, and much more to ensure a user-friendly and more navigable site.

At Tri-Cor we are excited for all that is to come with our improved image, growth, and advancements and hope you find these changes confirming Tri-Cor as your trusted source for your polyethylene packaging needs.

For more information on HubSpot®, Kuno Creative, or Fahoury Ink LLC, you can visit their websites listed below:

HubSpot®: http://www.hubspot.com/

Kuno Creative: http://www.kunocreative.com


Fahoury Ink LLC: http://www.fahouryink.com/

Fahoury Ink

Polyethylene Packaging 101

Resins…. Film thickness…. Tensile strength…. Impact resistance…. What do all of these terms mean to you when purchasing your polyethylene bags?

Unless you are a poly salesman or have a degree in Plastics Engineering, the terminology used in the industry probably makes your head spin. To assist you, we’ve created Polyethylene Packaging 101.


You may find it overwhelming with all the different resins available these days. How does one choose when you have octene, metalocene, butene, hexene, etc… A knowledgeable sales representative will be able to help determine what grade to use. Each grade has different characteristics and choices should be based on applications. Understanding resin properties is critical in formulating the right product for your specific application.

Film Thickness (Gauge)

Polyethylene film thickness is measured by thousandths of an inch, or milli-inch. The thickness of the bag does not always correlate into strength. A heavy gauge bag is not always strong. Most often it is a combination of resin grade and gauge relative to the application. A 2 mil octene linear bag will have more strength than a 2 mil butene linear.

Tensile Strength vs. Impact Resistance

  • Tensile strength is the maximum stress that a material can withstand while being stretched or pulled before breaking. Why is this important?

It’s important to have a plastic bag that is strong enough for your application. A plastic bag that holds 50 pounds of material must have adequate tensile strength, otherwise the bag will end up breaking.

  • Impact resistance is a material’s ability to resist shock loading. What does this mean?

Basically it is the film’s ability to resist being punctured. A punctured bag may result in contaminated goods or product loss.

When choosing the correct gauge and resin formula it is important to consider how tensile strength and impact resistance are relevant to your packaging application. An example that everyone can relate to is a garbage bag. I’m sure most have had failure in a garbage bag whether it breaks when lifting out of the can (tensile strength) or waste material punctures holes in it (impact resistance). With all these variables in choosing the correct formula for your polyethylene package, having a knowledgeable salesman is vital.

Who knew there was so much to know about making Polyethylene “Film and Bags”!?!