In-mold label material production process

The process of making in-mold labels consists of three parts, coextrusion-biaxial stretching (uniaxial stretching)-post-treatment.

(1) Coextrusion

The resin pellets of different compositions or formulas are put into different extruders and enter the same extrusion port under the action of high temperature and pressure, and the composite film material composed of different component resins is extruded.

(2) Biaxial stretching

The co-extruded material is stretched in the axial direction and the circumferential direction under the action of a mechanical device, so that its lattice is plastically deformed. The biaxially-stretched material has improved strength and hardness, which facilitates processing and application. In general, BOPP uses a biaxial stretching process.

(3) Uniaxial stretching

After the film is uniaxially stretched and deformed, its strength and hardness are improved, and it can be elastically deformed transversely, which is more suitable for irregular bottle bodies. Usually, the PE+PT material adopts a uniaxial stretching process.

(4) Post-processing

Post-treatment refers to the corona or coating treatment on the surface of the material, and the rolling of the surface of the adhesive layer. Corona or surface coating can improve the printability of the material, and the texture rolling produces a texture on the surface of the adhesive layer, which facilitates venting. After the processed material is recoiled, the large volume is subdivided into small rolls or leaflets, which are then sent to the customer as finished products.