Lamination

Lamination is the process of bonding two or more flexible film substrates together to create a single multi-layer packaging structure that performs better than any of the individual layers could on their own. It is one of the most important processes in flexible packaging manufacturing, and it is the reason why the packaging on most of the food, pharmaceutical and consumer products you encounter every day is made from more than one material.

The principle is straightforward: each layer in a laminated structure contributes something the others do not. One layer provides barrier performance. Another provides structural strength. Another provides a printable outer surface. Another provides heat sealability at the filling line. The lamination process bonds these layers into a unified structure that delivers all of those properties together, in the right order, with the right bond strength between each interface.

At NytronPackaging, lamination is central to almost everything we produce. Whether we are making a stand-up pouch for coffee, a vacuum bag for meat, a sachet for a pharmaceutical product or a roll of film for an automated filling line, lamination is what gives that packaging its performance.

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How Lamination Works

In adhesive lamination — the most widely used process in flexible packaging — a liquid adhesive is applied to one substrate, the solvent or carrier is evaporated in a drying tunnel, and a second substrate is then pressed against the adhesive-coated surface under heat and pressure in a nip roller assembly. The bonded web exits the laminator as a single unified structure and is wound into a roll for further processing — slitting, printing, bag conversion or direct despatch to the customer’s filling line.

The adhesive used in lamination is a critical component of the finished structure. It must bond the two substrates securely across the full range of temperatures, humidities and mechanical stresses the packaging will encounter — from the filling line through distribution and storage to the end consumer. For food packaging, the adhesive must also comply with food contact material regulations, and for high-barrier applications it must not compromise the barrier performance of the films it is bonding.

Solvent-Based and Solventless Lamination

We operate both solvent-based and solventless lamination lines, and the choice between them depends on the specific structure being produced and the performance requirements of the application.

Solvent-based lamination uses adhesives dissolved in an organic solvent carrier. The solvent is evaporated in the drying tunnel before the substrates are bonded, leaving only the cured adhesive in the finished structure. Solvent-based systems are well established, handle a wide range of substrate combinations reliably, and produce consistently high bond strengths — including in demanding applications such as retort packaging and high-barrier structures where the adhesive is exposed to elevated temperatures or aggressive product contact conditions.

Solventless lamination uses 100% solid adhesives — no solvent carrier — which are applied at very low coat weights and bonded immediately without a drying stage. The elimination of the solvent drying step makes solventless lamination faster and more energy efficient, and it removes solvent emissions from the process entirely. Solventless lamination is suitable for the majority of standard food and consumer packaging applications, and it is the preferred process for brands with sustainability targets around reducing VOC emissions in their supply chain. Where the application permits it, we specify solventless lamination as the default.

Common Laminated Film Structures

The number of possible laminated film structures is very large — almost any combination of printable outer film, barrier layer and sealant web can be bonded together depending on what the packaging needs to do. In practice, most flexible packaging applications are served by a relatively small number of well-established structures that have been refined over many years of commercial use.

BOPP / CPP is one of the most widely used structures in food packaging — a biaxially oriented polypropylene outer layer laminated to a cast polypropylene sealant. It is used for snack food, biscuits, confectionery, noodles, bakery products and a wide range of dry goods where moisture barrier and good seal performance are the primary requirements. It is also an all-polypropylene structure, which makes it compatible with PP recycling streams.

BOPP / VMPET / PE combines a printed BOPP outer layer with a vacuum-metallised polyester barrier layer and a polyethylene sealant web. The metallised PET layer provides a significant uplift in both oxygen and moisture barrier, making this structure suitable for products with more demanding shelf life requirements — coffee, nuts, crisps, dried fruit and similar categories where oxygen barrier is critical to product quality.

PET / PE is a versatile two-layer structure used across a wide range of food, personal care and industrial applications. The PET outer layer provides structural rigidity, excellent print surface and good temperature resistance, while the PE sealant provides reliable heat seal performance across a range of temperatures. It is used in sachets, pillow pouches, laminated roll stock and a wide range of pouch formats.

PET / Foil / PE is the high-barrier workhorse of food and pharmaceutical packaging. The aluminium foil layer provides an almost complete barrier to oxygen, moisture, light and aroma, making this structure suitable for the most shelf-life-sensitive products — retort-processed ready meals, pharmaceutical sachets, instant coffee, powdered ingredients and similar applications where barrier failure has serious consequences for product safety or quality.

Nylon / PE combines the outstanding puncture and abuse resistance of polyamide with the sealability and moisture barrier of polyethylene. It is the standard structure for vacuum packaging of meat, poultry, cheese and other products that require a packaging film tough enough to survive the physical demands of vacuum application, distribution and retail handling without pinholing or delaminating.

Barrier Performance in Laminated Structures

The barrier performance of a laminated structure is determined by the barrier properties of the individual layers and how those layers interact with each other at the lamination interfaces. A well-designed laminated structure can deliver a barrier performance that is significantly greater than the sum of its individual parts — because the layers work together to block different transmission pathways and reinforce each other’s weaknesses.

We specify barrier requirements at the outset of every project based on the shelf life target for the product, the sensitivity of the product to oxygen and moisture, and the storage and distribution conditions the packaging will encounter. We test finished laminated structures in our in-house laboratory against those barrier specifications before releasing production to the customer, and we document the results for every batch.

Bond Strength and Delamination Testing

The bond between laminated layers must be strong enough to survive everything the packaging goes through — filling line tension, heat sealing, handling, stacking, temperature cycling and the physical forces encountered in distribution. If the bond fails, the structure delaminates — the layers separate — and the packaging loses both its functional integrity and its appearance.

We test bond strength on every laminated production run using a peel test that measures the force required to separate the laminated layers. Results are checked against the minimum bond strength specification for the structure and application, and any batch that does not meet the specification is quarantined and reviewed before any decision is made about release. Bond strength targets are set at the brief stage and are agreed with the customer as part of the technical specification for the job.

Sustainability in Lamination

Traditional laminated structures that combine different polymer families — for example PET bonded to PE — present a challenge for end-of-life recyclability because the different materials cannot be easily separated. This is a genuine issue and one that the packaging industry is actively working to resolve.

We offer mono-material laminated structures — all-PE and all-PP — that deliver meaningful barrier and mechanical performance while maintaining compatibility with flexible film recycling streams. We also offer solventless lamination as the default process for applications where it is technically appropriate, reducing the solvent footprint of the production process. Where clients have specific recyclability targets or sustainability commitments that affect packaging specification, we include those requirements in the brief from the outset and design structures that meet both the performance and sustainability requirements together.

Working With Us

If you are specifying a new laminated packaging structure, reviewing an existing structure for performance, cost or sustainability reasons, or troubleshooting a delamination or barrier performance issue with your current packaging, we are happy to work through it with you. We will ask the right questions about your product, your process and your requirements, and we will give you a clear and honest technical recommendation.