UV-C Lamp Segmentation for Lacquer Scratch Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional UV crosslinking methods for lacquer layers on plastic substrates face challenges in achieving micro-scratch resistance without causing embrittlement, as increased crosslinking leads to thermal expansion mismatch and flaking, especially in automotive components with metallic appearances.
Innovation Solution
Incorporating a monochromatic UV-C lamp in addition to a high-pressure mercury lamp, with the UV-C lamp crosslinking the surface and the mercury lamp crosslinking the bulk, allowing for higher surface hardness without embrittling the entire paint layer, and using a cold light mirror to filter out IR radiation to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-pressure mercury lamp is used for UV crosslinking, then the lacquer layer achieves crosslinking and drying, but high process temperatures are generated that can damage plastic substrates
Solution Approach 1:
The patent segments the radiation spectrum by using a dichroic mirror to separate UV radiation from infrared radiation. The UV component is directed onto the lacquer layer for crosslinking, while the infrared component is reflected away, preventing excessive heating of the plastic substrate. This spectral segmentation resolves the contradiction between achieving effective crosslinking and avoiding substrate damage from high temperatures.
2Strength
If the degree of crosslinking is increased to improve micro-scratch resistance, then surface hardness increases, but the lacquer layer becomes more brittle and prone to flaking
Solution Approach 1:
The patent applies local quality by concentrating UV-C radiation specifically at the surface of the lacquer layer using a monochromatic UV-C lamp. This creates a hardened surface layer with high crosslinking density for improved scratch resistance, while the bulk of the lacquer layer maintains lower crosslinking and remains flexible. The differential crosslinking depth achieves surface hardness without overall brittleness.
3Reliability
If conventional broadband UV radiation is used, then the entire lacquer layer is exposed to UV radiation, but this causes uniform crosslinking throughout which leads to embrittlement
Solution Approach 1:
The patent changes the wavelength parameter of UV radiation by introducing a monochromatic UV-C lamp emitting at 254 nm, in addition to the broadband UV source. The UV-C radiation has different penetration characteristics and crosslinking efficiency, enabling surface-specific hardening without causing uniform embrittlement throughout the entire lacquer layer thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances micro-scratch resistance while maintaining paint adhesion and preventing flaking due to thermal or mechanical stress, without causing the paint to become brittle, and accelerates crosslinking speed while avoiding excessive heating.
Implementation Method 1
UV irradiation process involving an additional monochromatic radiation source
Implementation Method 2
a radiation source is used as the UV radiation source, which emits both UV radiation and visible light and a high percentage of infrared radiation
Implementation Method 3
a cold light mirror 7 rotated by 45 ° to the main radiation direction. The cold light mirror 7 reflects the UV light essentially downwards
Data Source
Figure 1
AI summary
The invention relates to a component, the surface of which is at least partially covered with a coating, wherein the coating comprises a PVD coating arranged between a first paint layer and a second paint layer and the first paint layer forms a base coat layer on the surface and the second paint layer forms a top coat layer having a top coat thickness on the PVD coating, wherein at least the top coat layer was produced with UV-curable paint. Proceeding from the interface of the PVD coating in a region smaller than the top coat thickness, the top coat layer has a lower degree of cross-linking induced by UV light than in the part of the top coat layer connected to said region. The invention relates in particular to a method for producing such a component.