At extrusion coating process a thin layer of polymer is applied onto a base, typically fibre-based paper. Extrusion coating makes packaging more durable and resistant to all sorts of damage. At KCL, we’re using cutting-edge 5-layer coextrusion technology to lead the charge in creating sustainable and high-performance packaging solutions.
Getting to Know Extrusion Coating
A molten layer of material, usually a polymer, is spread over a base to form a composite structure. This is what extrusion coating is all about. It’s a go-to method in the packaging world, ensuring your products stay safe and sound during their journey to you. The beauty of this process is its flexibility. Whether it’s paper, foil, or plastic films, we can tailor the coating to meet specific needs.
In today’s world, where sustainability is key, extrusion coating is important. By using biodegradable or recyclable polymers, we can create packaging that not only protects but also respects our planet.
How Does Extrusion Coating Work?
Process starts with melting a polymer resin, which is extruded through a flat die to form a thin film. This film is applied to a moving base, which is prepared to ensure it sticks well. Once cooled, you’ve got a tough, composite material ready to go.
Key factors like coat weight, adhesion, and neck-in evaluation are crucial here. Coat weight is all about getting the thickness just right. Adhesion ensures the coating stays put, and neck-in evaluation checks the film’s width consistency. It’s a bit technical, but these details make all the difference.
Why Choose Extrusion Coating for Packaging?
Extrusion coating enables superior high barrier packaging. Extrusion coating creates a strong barrier against moisture and oxygen, which is vital for keeping food and pharmaceuticals fresh. Plus, it makes packaging tougher, so it can withstand the bumps and knocks of transport. And with options for surface treatments like flame or plasma, the performance just gets better.
Extrusion Coating vs. Extrusion Lamination
While often confused, extrusion coating and extrusion lamination are distinct processes with different applications. In extrusion coating, molten polymer is applied directly onto a single substrate (typically paper or paperboard) as a protective or barrier layer. The polymer forms a coating that shields the substrate from moisture, oxygen, and other elements.
Extrusion lamination, on the other hand, uses the molten polymer as an adhesive layer between two substrates. The polymer essentially acts as a bonding agent, creating a multi-layer structure with different materials sandwiched together.
| Characteristic | Extrusion Coating | Extrusion Lamination |
|---|---|---|
| Function | Polymer serves as protective/barrier layer | Polymer serves as adhesive between substrates |
| Substrate Requirements | Single substrate (often paper-based) | Two or more substrates (can be different materials) |
| Typical Applications | Liquid packaging, moisture barriers, grease-resistant packaging | Food pouches, multi-layer industrial packaging, packaging requiring different properties in each layer |
| Processing Considerations | Requires substrate pretreatment for adhesion; focuses on surface properties | Requires precise temperature control to ensure proper bonding between layers |
At KCL, our expertise allows us to optimize both processes based on your specific packaging requirements. Understanding this distinction is crucial when selecting the most appropriate technology for your application, as it impacts material selection, production efficiency, and final product performance.
Innovative Uses of Extrusion Coating
From flexible pouches to industrial wraps, extrusion coating is everywhere. Its versatility means it can cater to both consumer and industrial needs. At KCL, our advanced technology allows us to create multi-functional packaging with superior barrier properties. Imagine combining different polymers to achieve heat resistance or chemical stability. That’s the power of our 5-layer coextrusion technology.
How Does It Compare to Other Methods?
So, how does extrusion coating stack up against other methods like lamination or solvent-based coatings? Unlike lamination, which uses adhesives to bond layers, extrusion coating applies a single, seamless layer directly. This results in a more uniform finish. And when it comes to being eco-friendly, extrusion coating wins hands down. It doesn’t rely on volatile organic compounds, making it a greener choice.
Extrusion Coating and Sustainability
Extrusion coating is a champion for sustainable packaging. By choosing the right polymers like biodegradable biopolymers, we can make packaging that’s easier to recycle or compost. Plus, the process itself is energy-efficient with minimal waste. It’s a win-win for the environment and the industry.
What’s Next for Extrusion Coating?
The future looks bright for extrusion coating, with new materials and technologies on the horizon. Innovations in biodegradable polymers and nanocomposites promise to boost performance and sustainability. At KCL, our pilot line, running at a speedy ~400 m/min with a 500 mm width, is where you can come to test and improve these new materials. By testing you can ensure they meet the highest standards, from sealability to pinhole resistance.
Co-Extrusion: Advanced Multi-Layer Technology
Co-extrusion represents a significant advancement beyond standard extrusion coating. In this sophisticated process, multiple extruders simultaneously feed different polymer materials into a single die head, where these individually extruded melts are brought together and eventually extruded as a unified multi-layer film. This technology enables the creation of packaging with multiple functional layers in a single structure, eliminating the need for additional lamination steps.
At KCL, our 5-layer co-extrusion technology stands at the forefront of packaging innovation. This advanced capability allows us to engineer packaging solutions with precisely tailored properties by combining different materials in a single pass. The advantages are substantial:
- Enhanced barrier properties – combining oxygen, moisture, and light barriers in a single structure
- Optimized mechanical strength – using cost-effective structural layers while maintaining premium surface properties
- Improved sealing performance – incorporating dedicated sealing layers without compromising barrier functions
- Resource efficiency – achieving multiple functionalities with minimal material usage
Co-extrusion excels in applications requiring complex performance profiles. For instance, in food packaging, we can create structures with an outer layer for printability, a middle layer for strength and stiffness, barrier layers to protect against oxygen and moisture, and an inner food-contact layer optimized for heat sealing and product compatibility. Similarly, pharmaceutical packaging benefits from the precise control of gas transmission rates and protection from light and moisture that only multi-layer structures can provide.
Our expertise in material selection and process optimization ensures that each layer works in harmony with the others, resulting in packaging that outperforms traditional single-layer extrusion coated products in demanding applications.
Extrusion Coating in Practice: Industry-Specific Applications
Extrusion coating technology delivers tailored solutions across various industries, each with unique packaging requirements and challenges. Let’s explore how this versatile technology is applied in different sectors:
Food Packaging
In food packaging, extrusion coating creates high-performance barriers that extend shelf life while maintaining food safety. PE-coated paperboard is commonly used for liquid packaging like milk cartons, while EVOH layers provide excellent oxygen barriers for sensitive products. For fatty foods, specialized coatings with grease resistance properties prevent staining and package degradation.
Pharmaceutical Packaging
Pharmaceutical packaging demands exceptional barrier properties and tamper evidence. Extrusion coating with PVDC or EVOH provides moisture, oxygen, and light protection critical for maintaining drug efficacy. Our technology enables the creation of child-resistant yet senior-friendly packaging that meets strict regulatory requirements.
Industrial Packaging
Industrial applications benefit from extrusion coating’s durability and protective properties. Heavy-duty sacks for chemicals and construction materials utilize PE-coated kraft paper that combines strength with moisture resistance. For corrosion-sensitive equipment packaging, VCI (Volatile Corrosion Inhibitor) additives can be incorporated into the polymer layer.
Consumer Products
Consumer goods packaging balances protection with aesthetics and sustainability. Extrusion coating enables vibrant printing surfaces while providing barrier properties for cosmetics, household products, and personal care items. Metallized substrates with specialized coatings create premium packaging with excellent barrier properties.