What is the process of extrusion coating lamination?

Extrusion lamination is a process by which thermoplastic resins are melted and plasticated in an extruder and the molten polymer is extruded through a T-die as a thin web, which is then coated onto a base material in a nip-roll assembly formed by a steel chill roll and a rubber-covered pressure roll, and finally laminated with one or two kinds of base materials to produce desired laminate product.

Step-by-Step Process of Extrusion Coating Lamination:

1. Substrate Preparation

The base material (e.g., paper, plastic film, aluminum foil, or fabric) is unwound from a roll.
It may undergo pre-treatment (e.g., corona treatment) to improve polymer adhesion.

2. Polymer Extrusion

A thermoplastic resin (commonly LDPE, PP, or EVA) is fed into an extruder.
The extruder heats and melts the polymer, pushing it through a flat die to form a thin web, molten curtain.

3. Lamination

The molten polymer is pressed between the substrate and a chill roll (or another layer in multi-layer lamination).
Pressure from the nip roller ensures strong bonding as the polymer cools and solidifies.
Laminator consists of chill roll, silicone rubber covered pressure roll, back roll, trimming device, wheelwork device, pneumatic device,etc. It is used to combine molten film with base materials.

4. Cooling & Solidification

The coated substrate passes over a chilled roller to rapidly cool and set the polymer layer.
This ensures smooth adhesion and prevents wrinkling.

5. Trimming 

Shrink-width makes edges thicker, which need to be trimmed, otherwise the laminating film will have some quality problems such as drape, crimp, and unevenness.
It is convenient to renew cutter blades and adjust cutting width, thus saving time and labor.

6.Rewinding

We have different types of rewinder, it includes double station turret rewinding, double sided roun plate rewinding and other is friction press roll rewinding. It is chosen based on customer’s requirements and products.
This auto-splicing rewinder consists of tension control system, splicing device, rectifying device, etc. It can change reels without stopping nor slowing down the machine, thus increases efficiency, reduces waste and saves manpower. 

Key Advantages of Extrusion Coating Lamination:

✔ Strong Bonding – Polymer chemically bonds to the substrate.
✔ Barrier Properties – Improves resistance to moisture, oxygen, and grease.
✔ Versatility – Works with various substrates (paper, foil, films).
✔ Cost-Effective – Lower material costs compared to pre-made films.
✔ High production speed
✔ Environmentally favorable when replacing solvent-based lamination

Challenges

Requires precise temperature and pressure control

Substrate surface treatment (like corona discharge) may be needed to ensure adhesion

Equipment investment is relatively high

Common Applications:

Food Packaging (juice cartons, milk cartons,snack bags)

(snack bags)

Medical Packaging (sterile barrier films)

Industrial Films (moisture-resistant liners)

This process is widely used in flexible packaging to create durable, functional materials with improved performance. Let me know if you need further details!