Packaging “Silicone Oil / Release Agent” Migration Boundaries: Anti-Stick Coatings, Food-Grade Coated Paper, and Label Release Liners — The First 3 Reports a Printer Should Request for “Can This Paper Hold Food?” Orders

In March 2026, a baking-sector customer contacted us to print a batch of paper cup trays.

When discussing the production process, the client specifically emphasized: “We need food-grade silicone oil, and the supplier says it has FDA certification.”

They then sent us a PDF report more than 20 pages long, which looked comprehensive.

We reviewed it for three minutes and immediately identified the problem: it was a report issued by a raw silicone oil supplier, testing the raw material itself—purity, heavy metals, and migration. However, the client wanted us to use a release agent coated onto paper, which is a different matter.

The reason is straightforward: raw-material compliance does not mean the product remains compliant after coating. Once the release agent is applied to paper, the finished surface is also affected by variables such as paper-base fibers, inks, coating weight, and curing conditions. This report can prove that “the drum of silicone oil itself is safe,” but it cannot prove that “the finished paper cup tray is safe when it contacts cake during printing and use.”

The client said, “Then I will ask for another one.”

What we actually needed was not “a better report,” but 3 specific reports, because silicone oil migration involves 3 independent assessment layers. Today, we will clarify these 3 layers.

The First Boundary: Why Release Agents Need to Be Used in Packaging

First, one point must be made clear: silicone oil itself is not a hazardous substance; the issue is that “it can migrate,” and this migration has boundaries. Silicone oil is a class of organic silicone polymers widely used in food-contact materials, including coated pans, baking molds, and silicone kitchenware. Its problem is not toxicity but the fact that it readily migrates from the substrate surface into the contact material.

In packaging, silicone oil mainly appears in 3 locations, each with completely different risks:

There is one point in this table that customers most often misunderstand: “food-grade paper cup stock” does not mean “paper coated with silicone oil.” Most food-packaging coated paper uses PE (polyethylene), not silicone oil. PE-coated paper follows a completely different technical route for food-contact compliance, with GB 4806.7 covering plastics and GB 4806.10 covering coatings. Silicone release agents are used extensively in paper trays and liner paper intended for direct baking contact, where anti-stick performance is required and silicone remains the most mature solution.

Therefore, a customer's first statement is often inaccurate: “We need food-grade silicone oil.” What they actually mean is “We need anti-stick paper that can directly contact baked food.” These 2 requirements follow different testing pathways.

The Second Boundary: Migration Is Not About “How Much Silicone Oil There Is,” but “How Much Migrates Under What Conditions”

The second boundary is the technical core and the area where customers most often leave printers without an answer: silicone oil migration test results depend heavily on the test conditions.

There are 3 key variables: contact temperature, contact time, and the water content of the contact medium.

• Temperature: Migration at a baking temperature of 180℃ can differ from migration at room temperature by an order of magnitude.
• Time: The measured values after 2 hours of contact and after 24 hours of contact will differ.
• Water Content of the Medium: This is the most counterintuitive factor. The same paper contacting dry biscuits and a moist cake can show very different silicone oil migration levels because water can carry silicone away from the surface.

Therefore, when a customer presents a report stating “migration: 0.5 mg/dm², compliant with the standard,” we always ask 3 questions: What temperature, what duration, and what medium? If these 3 questions cannot be answered, the report has no reference value for their product.

Another common misunderstanding is confusing “overall migration” with “specific migration.” Overall migration measures “how much of everything has come out of the packaging,” while specific migration determines whether “the substance that came out is on the authorized list.”

For a baking tray, the more important question is: Is the chemical structure of this silicone oil on the authorized list? The EU has EU 10/2011, while the United States has corresponding provisions in FDA 21 CFR. If the customer is exporting to the EU, a report showing that migration levels do not exceed the limit is insufficient; proof is also needed that the specific substance is permitted for food contact.

One real-world pitfall is that the report provided by a customer may say “siloxane,” while the corresponding authorized-list entry may refer to a specific polydimethylsiloxane with a particular structure. A similar name does not mean compliance. This is the same type of issue as “white cardboard” and “white cardboard stock”: a generic name is not an authorized entry.

The Third Boundary: Finished Product vs. Raw Material—Who Issued the Report and What Does It Cover?

Returning to the baking customer from the beginning, we ultimately requested 3 documents. Initially, the client felt this was excessive.

First: A migration report for the finished coated product. This must not be a raw-material report. Migration testing must be performed on the finished product, or on a sample produced using the same process and batch, after the intended paper base, release agent, coating weight, and curing conditions have been applied. The report must identify the paper, release agent, coating weight, test temperature, and test duration used for the sample.

Second: Substance-level documentation for the release agent itself. This should take the form of the supplier's declaration of compliance and safety data sheet (SDS), matched to the authorized list in the destination country, such as the EU 10/2011 positive list, US FDA requirements, or the Chinese GB 4806 series. This document answers whether the substance itself is permitted, not how much migrates.

Third: A printing-side assessment of migration impact. This document is most often overlooked. Printing inks, film lamination, varnish coating, and die cutting can all affect the final surface condition. There are 3 common scenarios:

• Ink comes into direct contact with the release layer: Solvents or plasticizers in the ink may affect the uniformity of the release layer or even cause localized rupture, changing the migration pathway.
• Hot foil stamping / UV is applied to the release surface: Localized high temperatures may alter the structure of the release layer. For these applications, we generally recommend that customers conduct a thermal test first.
• Film lamination: If the laminated area covers the food-contact surface, the actual contact surface has changed. Using a report for an unlaminated product to demonstrate that the product remains safe after lamination creates a logical gap.

Only when all 3 documents are available can we confidently state, “We can handle this order.” If they are incomplete, we will clearly state in the quotation which items the customer must provide. Otherwise, production will proceed according to the customer's submitted report, with responsibility borne by the customer.

When a Printer Receives an Order Asking “Can This Paper Hold Food?”, What Should They Ask First?

After summarizing the 3 layers above, they can be reduced to 3 questions that can be asked directly.

Question 1: “Is the silicone oil coated on the food-contact side or on the opposite side?” This determines the overall risk level. If the release agent is applied to the back and the food does not contact it, the migration pathway is entirely different. Some baking trays have a PE water-resistant front and silicone anti-stick back, while others are silicone-coated throughout. Clarify the location before discussing reports.

Question 2: “Under what conditions was the report tested—temperature, duration, and medium?” A report that does not specify these 3 conditions is effectively no report at all. This question also reveals whether the customer genuinely understands the issue or simply wants to place the order quickly.

Question 3: “Does the report cover the raw material or our finished product?” If the customer has provided a raw-material report, we need to explain the difference and why finished-product data are required. Many customers are not unwilling to cooperate; they simply do not know what to request. Once this is explained clearly, suppliers will generally cooperate.

A Message for Customers

The essential understanding about silicone oil is this: it is not a question of whether it can be used, but a question of how much is used under what conditions.

The same drum of silicone oil carries completely different risk levels when applied to anti-stick liner paper and label release liners. Likewise, the same finished paper tray produces completely different migration levels when holding dry biscuits and cream cake. Therefore, any claim of “food-grade” or “standard-compliant” that omits the conditions is incomplete.

Our recommendation is to obtain all 3 reports at once and record them in the order confirmation. This is not intended to create difficulties for anyone. In recent years, the baking industry has experienced numerous incidents involving packaging migration, and customers are themselves being held accountable by brand owners. When printers clarify the conditions and formalize the documentation, both parties are protected.

Further Reading

• Food-Contact Packaging Migration: GB 31604 vs EU 10/2011—3 Boundary Differences Most Often Encountered by Printers—This article provides the regulatory framework for migration assessment.
• 3 Practical Assessment Boundaries for Ink Migration in Food Packaging—10mg/dm² Limit / Desiccants / Shelf Life—Ink migration and silicone oil migration follow independent pathways.
• 5 Core Standards for Food Packaging: GB 4806.1/7/8/9/11—This explains the respective scopes of GB 4806.7 for plastics and GB 4806.10 for coatings.
• Paper Packaging “Barrier Coatings”—3 Practical Failure Boundaries: Heat-Seal Adhesion / Crease Cracking / Condensation Immersion—This examines how coatings fail structurally.
• 3 Types of Accessories That Defeat the “Recyclability” of Paper Packaging: Magnets / Metal Buckles / PVC Windows—This focuses on accessories and the position of silicone coatings within recycling systems.