To make the products stand out with a personalized touch, most of the formed packaging materials need to undergo surface coloring treatment. There are various surface treatment processes for daily chemical packaging materials. Here, we mainly introduce several common processes in the cosmetics industry, such as vacuum coating, spraying, electroplating, anodic oxidation, and injection molding color change processes.

Vacuum coating mainly refers to a category of products that require coating under high vacuum. The specific operation involves placing the film substrate to be coated into a vacuum evaporation coater, using a vacuum pump to evacuate the chamber, so that the vacuum degree of the coating environment reaches 1.3×10⁻² to 1.3×10⁻³ Pa. Subsequently, the crucible is heated to melt and evaporate high-purity aluminum wire (with a purity of 99.99%) into gaseous aluminum at a temperature of 1200°C to 1400°C. The gaseous aluminum particles deposit on the surface of the moving film substrate, and after cooling and reduction, a continuous and bright metallic aluminum layer is formed

· Process Cost:

· Mold cost: None

· Single-piece cost: Medium

· Production Suitability: Suitable for both single-piece and mass production

· Quality: High quality, with high brightness and product surface protective layer

· Speed: Moderate production speed, 6 hours/cycle (including painting)

Composition of Vacuum Coating Process System

1. Electroplating Equipment

Vacuum plating is the most common metal surface treatment technology. Since no molds are required, the process cost is very low. Lifelike colors can also be applied in vacuum plating, enabling the product surface to achieve the effects of anodized aluminum, bright chrome, gold, silver, copper, and gunmetal (a copper-tin alloy). Vacuum plating can treat the surface of low-cost materials (such as ABS) to achieve the effect of a metal surface at a low cost. The surface of the workpiece for vacuum plating should be kept dry and smooth; otherwise, the surface effect will be greatly affected.

Materials Used in Vacuum Plating

· Metallic Materials: Gold, silver, copper, zinc, chromium, aluminum, etc. Among them, aluminum is the most widely used.

· Plastic Materials: Applicable, such as ABS.

Process Flow (Taking a Plastic Part as an Example)

First, a primer is sprayed onto the workpiece, followed by electroplating. Since the workpiece is a plastic part, air bubbles and organic gases may remain during injection molding, and moisture in the air will be absorbed during storage. Additionally, due to the uneven surface of the plastic, direct electroplating will result in a rough surface with low gloss and poor metallic appearance, as well as defects such as bubbles and water bubbles.

After spraying a layer of primer, a smooth and flat surface is formed, which eliminates the bubbles and water bubbles inherent in the plastic itself, allowing the electroplating effect to be fully displayed.