Metallized PET Film for Oil-Contact Packs

Metallized PET Film used around oily foods or liquid formulations must protect more than oxygen and light. Oil migration, moisture, heat and contaminated seals can expose weak interfaces, leading to metal transfer, delamination or leakage even when the incoming roll looks uniform.

A Metallized Film Supplier needs the product composition and process history before recommending a grade. Cailong’s chemical-enhanced VMPET range is intended for applications that require closer control of the aluminum-to-PET interface and water or heat resistance. The complete laminate still requires qualification.

Oil Can Reach Interfaces in Several Ways

The product-contact sealant is the first barrier between the filling and the metallized web, but oil may move through imperfect seals, cut edges, pinholes or damaged areas. During filling, oil or seasoning can also contaminate the seal region. A failure investigation should identify where the product first reached the interface.

Do not assume that a delaminated area proves the metal layer was the first failure. Separation may begin at the ink, primer, adhesive, metal or sealant interface. Peel the sample carefully, photograph both faces and record which layer transferred.

Choose the Grade around the Exposure

A general VMPET may remain suitable for a dry product and ambient process. A chemically enhanced or high-adhesion grade deserves evaluation when the laminate faces oily contents, humidity, pasteurization or hot-water heating. Grade selection should follow the combined exposure rather than the product name alone.

State oil type, acidity, water content, filling temperature, heating cycle and storage condition. A coffee bean pouch, seasoning sachet and oily sauce pouch can all involve oil, but the interface stress and seal contamination are different.

Build the Barrier Web into a Protected Structure

One possible structure is printed PET / enhanced VMPET / PE. The outer PET carries printing and protects the middle barrier web, enhanced VMPET supplies light and gas barrier, and PE provides product contact and sealing. For higher-temperature processes, the sealant and adhesive must be selected for that exact cycle.

Confirm metal-side orientation, treatment side, adhesive application and cure schedule. If the barrier web is reversed or the adhesive does not match the functional surface, a stronger VMPET grade cannot correct the construction error.

Test with the Actual Oil and Temperature

Prepare clean laminate controls and filled-pouch samples. Measure bond condition before filling, after cure, after product contact and after the required heat or storage exposure. Inspect metal transfer, bubbles, whitening, curl, odor, leakage and seal behavior.

Use the intended pouch size and fill weight. A small coupon cannot reproduce pressure, gusset flexing or oil movement at the edges. If consumers heat the pouch, include handling while warm because softened layers and internal pressure can expose weaknesses that remain hidden after cooling.

Keep Barrier and Adhesion as Separate Decisions

High metal adhesion does not automatically establish the required OTR or WVTR, and a strong incoming barrier does not prove oil resistance. Request both sets of grade-specific information with methods and conditions. Repeat relevant barrier measurements after conversion when the process could damage the metallized layer.

Send Cailong the formulation category, current laminate, pouch drawing, filling temperature, heat treatment, storage route, observed failure and acceptance tests. This allows the chemical-enhanced VMPET trial to address the actual interface risk instead of relying on a broad “oil-resistant” description.