1. What is PLA film coating?

Coating is the core process for producing disposable paper cups and paper bowls. Simply put, it is to evenly apply melted plastic particles onto the surface of paper to form a very thin and dense protective film. This layer of film determines whether the paper cup can hold liquids.

The traditional coating material is PE (polyethylene), which has good performance and low cost, but the biggest problem is its non degradability.

PLA coating refers to replacing PE with PLA (polylactic acid). PLA is a biobased material fermented from plant starch such as corn and cassava. Under specific conditions (such as industrial composting), it can be completely decomposed into carbon dioxide and water, making it very environmentally friendly.

2,The processing flow of PLA film coating

The production process of PLA coating is similar to traditional coating, but with higher requirements for each step:

Raw material preparation: PLA particles need to be thoroughly dried at 60-80 ° C to remove moisture and prevent hydrolysis during high-temperature extrusion, which can lead to a decrease in material properties.

Extrusion: The dried PLA particles are heated to about 200-220 ° C in an extruder and melted into a fluid.

Casting: Molten PLA flows out of the T-shaped die to form a thin film, which is quickly attached to the surface of the rapidly moving paper through an air knife or pressure roller.

Composite: Under the pressure and cooling action of the cooling roller, the PLA film is firmly adhered to the paper, forming PLA coated paper.

Post processing: The coated paper is rolled into large rolls, then printed and die cut (into fan-shaped pieces). Some manufacturers will perform constant temperature and humidity treatment on the fan-shaped pieces after this step, and finally send them to the paper cup forming machine for heating and mold stamping to produce the final paper cup.

Overall, PLA coating is a promising but technology intensive environmental solution. It solves the environmental pain points of traditional paper cups through material modification and process innovation without sacrificing the user experience. With the tightening of global "plastic ban/restriction" policies and the continuous maturity of technology, the application scope and market share of PLA coated paper products are expected to steadily increase.