Plastic product consistency and color integrity: Using nitrogen from nexAir for better outcomes

Plastic changes color when it oxidizes at high temperatures. What starts as bright white resin can come out of the mold yellowed or discolored if oxygen reaches the molten plastic during processing. Dark colors aren’t immune either – oxidation creates inconsistent shading and surface imperfections that show up under certain lighting conditions.

Nitrogen prevents this by displacing oxygen around the molten plastic. The inert atmosphere keeps the plastic from reacting with air while it’s hot and vulnerable. This matters most for light-colored products where even slight discoloration is visible, and for applications where color consistency across production runs is part of the spec.

Where Oxidation Causes Problems

Medical device housings molded in white or light gray show oxidation immediately. Even minor yellowing fails quality inspection because it suggests degradation that could affect material properties. Automotive interior components have similar issues – color matching across multiple parts requires each piece to come out of the mold with identical coloring. Food packaging film is another area where oxidation creates problems. Discolored packaging looks old or contaminated even when it’s fresh off the line. Nitrogen blanketing during extrusion prevents the discoloration and maintains the clear or bright colors that packaging designs require.

Consistency Across Long Production Runs

A production run might make thousands or tens of thousands of identical parts over several days or weeks. Parts molded on Monday need to match parts molded on Friday in both color and physical properties. Small variations in processing conditions can create noticeable differences, and oxygen exposure is one of those variables. Nitrogen purging removes oxygen as a source of variation. The plastic experiences the same inert atmosphere regardless of when in the production run it gets molded. This improves batch-to-batch consistency, which reduces rejected parts and customer complaints about color mismatches.

Purity Levels and Cost Considerations

Standard industrial nitrogen works fine for most plastics manufacturing. It contains low enough oxygen levels to prevent oxidation in typical molding and extrusion applications. Ultra-high purity nitrogen costs more but doesn’t provide additional benefits unless you’re working with particularly sensitive resins or meeting specific regulatory requirements.

Food contact packaging and medical devices sometimes require documentation showing the nitrogen purity used during manufacturing. Those applications might justify higher purity grades, but most commercial and industrial plastics don’t need it. Using the right purity level for your application keeps costs reasonable without sacrificing product quality.

Setting Up Nitrogen Delivery

Facilities with steady, high-volume needs typically use bulk nitrogen tanks that get refilled on a schedule. Smaller operations or those with variable production might stick with cylinder delivery or microbulk systems that fit between cylinders and full bulk installations.

The right setup depends on how much nitrogen you use and how consistent that usage is. We look at your production schedule and consumption patterns to figure out what delivery method makes sense. Our expert KnowHow™ developed through decades of working with plastics manufacturers gives us a realistic picture of what different facilities need versus what standard recommendations suggest.

Concerned about color consistency or oxidation in your plastic products? Contact nexAir to discuss nitrogen options for your production process.