Creating Water-Resistant Corrugated Packaging

Many products require packaging that can withstand moisture exposure—from refrigerated foods to outdoor storage. Here's how to create water-resistant corrugated packaging.

Water Resistance Requirements:

Different applications need different levels of protection:

• Light duty: Occasional humidity exposure (45+ minutes Cobb test)

• Medium duty: Cold chain, refrigerated transport (30-45 min Cobb)

• Heavy duty: Wet environments, ice contact (15-30 min Cobb)

Methods for Water Resistance:

1. Wax Coating/Curtain Coating:

Traditional method applying melted wax to board surface. Provides excellent moisture barrier but makes recycling difficult. Best for single-use applications.

2. Water-Resistant Adhesives:

Special adhesive formulations that maintain bond strength even when wet. Xuegong's alkali-free adhesives offer improved water resistance compared to traditional formulas.

3. Treated Linerboard:

Paper mills can apply water-resistant treatments during manufacturing. More expensive but maintains recyclability.

4. Coatings and Laminates:

Polyethylene or other plastic coatings create excellent barriers but impact recyclability. Bio-based alternatives are emerging.

Choosing the Right Approach:

Consider these factors:

• Duration of moisture exposure

• Recycling requirements

• Cost constraints

• Food contact requirements

• Customer specifications

Testing Standards:

• Cobb Test: Measures water absorption over time

• Water Immersion Test: Checks bond integrity after soaking

• Humidity Conditioning: Tests performance at high RH