Improving Ink & Adhesive Bonding for Packaging Applications

 

• Direct container printing
• Lot & date code printing
• Label adhesion
• Folding carton glue flap bonding

In this 30-minute webinar, plasma surface treating expert Wilson Lee shares insights on how these in-line treatment technologies are being implemented to solve adhesion challenges in the packaging world. A wide variety of materials are covered including, HDPE, PET, PP, ABS, Nylon 66, coated paperboard and more.

Webinar Transcript:

[00:01:34] Introduction: Why Plasma and Flame Surface Treatment Matters

We’re going to look at plasma and flame surface treatment—why you might need it, what plasma does to a surface, and review a few applications in packaging.

[00:01:54] Industries and Applications

Who is using plasma and flame? It’s easier to ask who isn’t. Over the past decade, these technologies have expanded into more industries every day. Surface quality is critical for printing, bonding, labeling, potting, and more. Manufacturing teams now realize that surface quality directly impacts product performance.

Common industries include:

• Automotive
• Aerospace
• Window and door assemblies
• Medical devices
• Electronics
• Decorating and packaging

[00:02:52] Examples of Applications

• Labeling and Printing: Direct print on bottles, terminal blocks, tubing, and toothbrush handles.
• Automotive: Dashboards treated with flame before applying decorative coatings.
• Assembly and Bonding: Window frames treated with plasma for better adhesive performance.
• Potting Electronics: Flame treatment ensures waterproof seals for outdoor circuits like headlamps.

[00:05:03] The Science Behind Surface Treatment

Two forces are at play:

• Cohesion: Holds liquids together (e.g., water droplets).
• Adhesion: Bonds liquids to surfaces.

To achieve strong bonds, adhesion forces must exceed cohesion forces. Surface treatment increases adhesion by raising surface energy.

[00:06:32] Surface Energy and Dyne Levels

Plastics start with low surface energy:

• Polypropylene: ~30 dyne
• ABS & Polycarbonate: ~42 dyne

For strong bonding, you need to raise surface energy into the 50–70 dyne range. Plasma and flame treatment make this possible.

[00:07:42] Adhesion Impediments

Challenges include:

• Low-energy materials
• Surface contamination
• Additives and flame retardants

These factors create hydrophobic surfaces that resist bonding. Plasma treatment solves this by cleaning and activating surfaces.

[00:10:17] Alternatives to Plasma and Flame

• Wet Chemistries: Primers and solvents (labor-intensive, inconsistent).
• Mechanical Prep: Sanding or blasting (time-consuming, wears parts).
• Vacuum Plasma: Effective but slow and costly for high-volume production.

Atmospheric plasma and flame offer inline, repeatable, and cost-effective solutions.

[00:12:51] What Plasma Actually Does

1. Cleans the Surface: Removes static, dust, and hydrocarbons.
2. Etches the Surface: Adds microscopic roughness for better bonding.
3. Functionalizes the Surface: Adds polar groups to increase surface energy.

[00:14:06] Technologies We Use

• Blown Arc Plasma: Treats wider areas at moderate speeds.
• Blown Ion Plasma: High-speed treatment for narrow lines and crevices.
• Flame Plasma: Ideal for large, multi-dimensional parts.
• Blown Ion 500: High-speed, consistent treatment for wide surfaces.

[00:22:52] Lab Results

Example: Polypropylene untreated vs. treated

• Untreated: 30 dyne, contact angle 94°
• Treated with Blown Ion: 58 dyne, contact angle 47°
• Treated with Flame: 79 dyne, contact angle 38°

Higher dyne levels and lower contact angles = better adhesion.

[00:25:16] Applications in Action

• Bottle Printing: Plasma pretreats surfaces for direct inkjet printing.
• Tube Sealing: Plasma improves crimp seals for packaging.
• Terminal Blocks: Plasma ensures ink adhesion on nylon parts.
• Labeling & Direct Print: Plasma and flame enable permanent graphics on bottles.
• Folding Cartons: Plasma improves glue adhesion at high speeds.

[00:33:48] Key Takeaways

• Improves quality, reduces costs, and supports high-speed production.
• Inline treatment eliminates costly, inconsistent prep methods.
• Improves quality, reduces costs, and supports high-speed production.