Why Add a Corona Treater to a Flexo Printing Machine for PP Woven Bags?

Adding a corona treater to a flexographic printing machine is optional for many PP woven bag factories—but it can significantly improve printing quality and production stability under certain conditions. This article explains what a corona treater is, why some PP woven fabric requires corona treatment, and when it is recommended for your production.
 

What Is a Corona Treater?

A corona treater is a device used to increase the surface energy of PP woven fabric or film materials.
Polypropylene (PP) is a naturally low-surface-energy material, which means ink adhesion can be weak without surface activation. Corona treatment modifies the surface tension, making the material easier to print or laminate.
Key function: Improve surface energy so ink bonds better with the material.
 

Do All PP Woven Fabrics Need Corona Treatment?

No.
Compared with plastic films (BOPP, PET, PE film), PP woven fabric normally has higher surface roughness, allowing ink to mechanically penetrate the fibers.
That's why most unlaminated PP woven bags can be printed normally without a corona treater, and many manufacturers do not use it.
But corona becomes very useful in the following conditions.
 

When Is Corona Treatment Recommended?

Below are the most common scenarios where corona treatment improves printing results.
 

1. Laminated or Coated Woven Fabrics (BOPP / Extrusion Coating / CPP Film)

When PP woven fabric is laminated or coated, the top layer becomes smooth film, not fabric.
Film has low surface energy and usually requires corona treatment for better ink adhesion.

Benefits:
Prevents ink from beading or smudging
Ensures strong bonding with BOPP or coated surface
Improves long-term print durability
 

2. Low Dyne Level or Difficult Materials

Some PP woven fabrics may have low dyne level, especially:
Recycled PP woven fabric
Very smooth woven fabric
Bags stored for a long time
Bags exposed to humidity or dust
Corona treatment can raise dyne levels quickly to ensure stable printing.
 

3. High-Speed Printing or Fine Designs

If your designs include:small text, fine logos, multi-color registration,
Corona treatment helps improve ink anchoring so the print remains sharp at high machine speed.
 

Benefits of Adding a Corona Treater to a Flexo Printing Machine

Wenzhou Qianfeng Machinery supplies optional corona treater units for all flexographic printing machines.
The advantages include:
Better ink adhesion on both PP woven fabric and laminated film
Higher print clarity, especially with small letters or multi-color designs
Reduced ink consumption because ink wets the surface more efficiently
More stable printing quality when producing different material batches
Suitable for multi-purpose production, including unlaminated and laminated bags

You don't need exaggerated descriptions—just clear functional benefits tied to real production needs.
 

When Corona Treatment Is NOT Necessary

For customers printing on unlaminated PP woven fabric only, corona treatment is optional.
Most factories can print normally without it because the woven texture naturally helps ink adhesion.

However, adding a corona treater gives you flexibility in case:
You print mixed materials
You may produce laminated bags in the future
You want more consistent print quality across varying fabric batches
 

FAQ

Q1: Is corona treatment mandatory for PP woven bags?
A1: No. For unlaminated PP woven bags, many factories print without corona treatment. It is mainly recommended for laminated or coated materials.
Q2: Will corona treatment damage the woven fabric?
A2: No. The treatment only modifies the surface energy and does not affect the material strength.
Q3: If we produce both laminated and unlaminated bags, what solution do you recommend?
A3: We recommend adding a corona treater. It keeps your printing line flexible and stable for both materials.
 

Contact Us for Machine Recommendations

If you are unsure whether your PP woven fabric requires a corona treater, we can evaluate your material, printing design, and machine setup to provide professional advice.

Email: [email protected] / [email protected] 
WhatsApp: Camela+86-15868562229 / Leilei +8615868562226
 

Wenzhou Qianfeng Machinery Co., Ltd.
12 Dec., 2025