What Is Extrusion?

What Is Extrusion?

Extrusion is the high-volume manufacturing process in which raw plastic is melted and formed into a continuous profile.extrusion pe machine coating with kraft paper The process yields items such as pipe/tubing, weatherstripping, fencing, deck railings, window frames, plastic films and sheeting, thermoplastic coatings, and wire insulation. Extrusion can also be used to coat paper and other substrates. Extrusion is a common method of producing paper-based cups for beverages in the food service industry, since it offers a solution that is both biodegradable and compostable. The coating, which is derived from renewable resources, adds strength and performance to the cup while providing an opportunity for reuse through recycling or local authority-approved composting.

The process involves a series of steps that combines both an extrusion and lamination system to produce the final product.extrusion pe machine coating with kraft paper The resulting material is a thin layer of polyolefin (mainly LDPE and PP) applied to a paper or aluminum foil base film, forming a sealed package that does not use any adhesives. The extrusion/lamination process is commonly used in the packaging and food industries, as it provides a good seal that prevents moisture, light, oxygen, and odors from entering the package.

There are a number of different ways to apply the coating, including blown film extrusion, coextrusion, and sheet/film extrusion.extrusion pe machine coating with kraft paper Blown film extrusion uses a die to shape the melt into a tube that is typically much thicker than its diameter, and it uses air pressure to blow the molten plastic outward. The blown film then cools by pulling it through a set of cooling rolls called calenders or "chill" rolls, which determine the thickness and texture of the finished film.

Coextrusion is a similar process to blown film extrusion that allows multiple layers of different materials to be simultaneously deposited into the die. The advantage of this type of extrusion is that the individual layers can be engineered to meet a specific set of needs for a particular application. For example, the use of a polarizer layer can improve UV-absorption and texture, while the addition of a filler can provide better oxygen permeability.

A specialized form of LDPE that is heat and ozone stable can be used to increase a laminate's barrier properties. This material is often added to a PET-based film to improve its oleophilic and oleophobic characteristics, as well as its odour resistance, water vapour permeability, and mechanical strength.

An extrusion machine can be equipped with a dual-station winder that adopts constant-tension surface friction winding, pneumatic transverse cutting, roll changing without shutdown, and is equipped with adjustable edge-trimming device, edge-strip blowing device, and length counting device. The double station winder is also equipped with an automatic metering system to ensure precise web width control. In addition, the line can be rewound with a single or double-sided PE coated paper. It is suitable for woven sacks, tarpaulins, jumbo bags, and other industrial packaging products. The machine can also be used to coat jute, cotton, and polyester fabric with BOPP film, paper, aluminum foil, and other composite substrates.

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