1 Overview & Definition

Interleaving paper is a thin, lightweight sheet placed between stacked products—such as glass panels, ceramics, metal sheets, or printed materials—to prevent surface contact, abrasion, and contamination during storage and transportation. High-quality interleaving paper must balance several competing demands: it must be strong enough to handle without tearing, yet thin and light to minimise added bulk and cost.

2Physical & Mechanical Properties

Basis Weight & Caliper

Typical interleaving papers range from 17 to 60 g/m², depending on application. A consistent caliper (thickness) across the sheet is critical—uneven thickness creates pressure points that can mark or scratch sensitive surfaces.

Tensile Strength & Tear Resistance

The paper must resist tearing during high-speed automated insertion. Both machine-direction (MD) and cross-direction (CD) tensile values should meet application-specific minimums, and elongation at break should be controlled to prevent distortion under tension.

3Chemical Purity & Cleanliness

Low Ionic Contamination

For electronics and optical glass applications, interleaving paper must have extremely low levels of chloride, sodium, and sulfate ions. Ionic contamination can migrate onto substrate surfaces and cause corrosion, delamination, or optical defects.

pH Neutrality

A pH range of 6.5–8.0 (neutral to mildly alkaline with a carbonate buffer) protects acid-sensitive materials such as photographs and archival documents. Acidic papers accelerate yellowing and embrittlement of adjacent products.

4Surface & Moisture Performance

Smoothness & Release Properties

The paper surface must be smooth enough to avoid micro-scratching polished substrates (such as float glass or mirror-finish metals), yet possess sufficient friction to resist slipping during stacking. Some grades are engineered with silicone-free release coatings for easy separation without adhesive transfer.

Moisture Resistance & Dimensional Stability

Fluctuations in humidity cause paper to expand or contract, which can warp stacked goods or leave impressions. High-quality interleaving papers use refined pulps and internal sizing agents to maintain dimensional stability across a humidity range of 20–80% RH, preventing cockling and moisture-induced mark-off.

5Sustainability & Compliance

Leading manufacturers now produce interleaving papers from FSC-certified or recycled fibres, with full traceability through the supply chain. Chlorine-free bleaching (ECF or TCF) eliminates dioxin by-products, while biodegradability ensures minimal environmental impact at end-of-life. Compliance with REACH, RoHS, and food-contact regulations (where applicable) is increasingly expected by global customers in the automotive, pharmaceutical, and consumer electronics industries.