What is the Difference Between Glassine & SCK Paper?
Created on 10.31
As these two papers are often confused due to their somewhat similar appearance, but they are fundamentally different in composition and performance.
Here’s a detailed breakdown of the differences between Glassine and SCK Paper.
Executive Summary
- Glassine: A super-calendered (highly polished), dense, and smooth paper made from wood pulp. It is air and grease resistant but is not a true barrier and can be affected by humidity. It is acid-free and ideal for archival purposes.
- SCK Paper: A silicone-coated kraft paper. It is a standard kraft paper (often brown, but can be bleached) that has been coated with a layer of silicone. This makes it an excellent release paper that is highly resistant to sticking.
Detailed Comparison Table
Feature | Glassine Paper | SCK (Silicone-Coated Kraft) Paper |
Composition | Made from refined wood pulp that is super-calendered (pressed through hot rollers). | A base paper (typically kraft) coated on one or both sides with a layer of silicone. |
Primary Function | Barrier against air, grease, and dirt. Preservation. | Non-stick release liner. |
Surface Feel | Extremely smooth, glossy, and translucent. | Can be smooth or slightly textured, depending on the base kraft. Opaque. |
Grease/Oil Resistance | Excellent. Naturally resistant due to its dense, hydra-packed structure. | Excellent, but this property comes from the silicone coating, not the paper itself. |
Moisture Resistance | Poor. It is not waterproof and can become limp or translucent when humid. | The kraft base is not waterproof, but the silicone coating provides a good moisture barrier. |
Key Characteristic | Acid-Free & Archival. Will not yellow or degrade photos, stamps, or artwork over time. | Non-Stick & Heat Resistant. Designed to separate from sticky materials like adhesives, resins, and food. |
Common Applications | • Interleaving for stamps, photos, and valuable prints • Bakery and food wrapping (for greasy foods) • Envelope windows • Barrier layer in packaging | • Backing for adhesive labels, stickers, and tapes • Release liner for composites, resins, and fiberglass • Baking sheets (parchment paper is often SCK) • Non-stick layer for self-adhesive products |
Strength | Relatively weak; can tear easily. | Stronger and more durable due to the tough kraft base. |
Deeper Dive into Each Paper
Glassine Paper
Think of Glassine as a paper that has been processed to its maximum density. The wood pulp is beaten for a long time to break down the fibers, and then it's run through a supercalender—a stack of hot, polished steel rollers. This process flattens the fibers, closes the pores, and gives the paper its characteristic smoothness, gloss, and transparency.
- Why it's grease-resistant: The dense structure with no pores prevents oils from wicking through easily.
- The Archival Advantage: High-quality glassine is inherently acid-free and lignin-free, meaning it won't transfer any harmful chemicals to delicate items, making it the gold standard for storing photographs, historical documents, and stamps.
SCK (Silicone-Coated Kraft) Paper
SCK paper is a composite material. It starts with a base paper, which is most often sturdy kraft paper. This base is then coated with a thin, even layer of silicone. The silicone provides the key property: release.
- How the Release Works: Silicone has a very low surface energy, meaning most things (like adhesives, sticky dough, or uncured resin) don't want to stick to it.
- The Strength Factor: Because it uses kraft paper as a base, SCK is generally much stronger, more tear-resistant, and more rigid than glassine. This makes it ideal for industrial applications where the liner needs to be peeled off a sticky product without tearing.
How to Choose: A Simple Guide
- Use GLASSINE if:
- You are storing or interleaving valuable, delicate items like photos, stamps, or artwork.
- You need a grease-resistant wrapper for food like cookies, pastries, or sandwiches.
- You need a see-through, smooth paper that is not intended for high heat or extreme stickiness.
- Use SCK PAPER if:
- You need a non-stick barrier for something extremely sticky like adhesive labels, epoxy resin, or fiberglass.
- You are baking and need a non-stick baking sheet (parchment paper is a type of SCK paper).
- You need a stronger, more durable release paper that can withstand mechanical peeling processes.
In summary: Glassine is a high-end, archival, grease-resistant paper. SCK is an industrial-strength, non-stick release paper. Their applications overlap in grease resistance, but their core purposes are distinct.
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