Method for the partial coloring of plastic parts
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Solution Overview
Problem
Current methods for colour laser engraving of plastic components, particularly thermoplastic ones, are cumbersome and unsuitable for creating high-resolution colour images without requiring complex printing processes or multiple laser sources, and often result in images that are not durable or have poor resolution.
Innovation Solution
A method involving submerging a plastic component in a dye bath and irradiating it with focused non-ionising electromagnetic radiation, such as laser radiation, to achieve targeted partial dyeing only at the irradiated points, allowing for high-resolution colour elements to be created without the need for precise printing or multiple laser sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser engraving methods are used on plastic components, then colour images can be created, but the resolution is poor and the process requires multiple laser sources or complex printing processes
Solution Approach 1:
The patent applies parameter changes by modifying the physical state of the plastic material through controlled heating and dye infusion. By heating the plastic to a specific temperature range and introducing dye vapor, the material becomes receptive to color absorption only in laser-irradiated areas, enabling high-resolution color imaging with a single laser source.
Solution Approach 2:
The patent introduces dye vapor as an intermediary substance that mediates between the laser energy and the plastic substrate. The dye vapor condenses and infuses into the heated plastic surface, transferring color to the irradiated areas without requiring direct contact or complex multi-source coordination.
2Reliability
If conventional laser engraving methods are used, then colour elements can be produced, but the durability and resistance to scratching/chemical damage are poor
Solution Approach 1:
The patent applies preliminary action by pre-heating the plastic surface before laser irradiation. This pre-heating creates a receptive state in the plastic that allows subsequent dye infusion to bond strongly with the material, ensuring durable color fixation that resists scratching and chemical damage.
Solution Approach 2:
The patent utilizes phase transitions of the dye material, which transitions from vapor phase during infusion to condensed phase during cooling. This phase change ensures deep penetration and strong adhesion of the dye to the plastic substrate, creating durable color elements that maintain integrity under various conditions.
3Manufacturing precision
If the plastic component is heated for dye infusion, then colour absorption is improved, but the risk of deformation or damage to the plastic increases
Solution Approach 1:
The patent applies periodic action through pulsed laser irradiation and controlled heating cycles. The heating is applied in controlled intervals that allow the plastic to reach optimal dye-reception temperature without exceeding the deformation threshold, and cooling periods allow stress relaxation between irradiation cycles.
Solution Approach 2:
The patent carefully controls the temperature parameter within a specific range that optimizes dye absorption while remaining below the plastic's deformation temperature. By maintaining the heating temperature in this critical window and controlling the duration of exposure, the process achieves high color absorption without causing warping or damage.
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 enables the creation of high-resolution, durable colour elements on plastic components, suitable for applications like security documents, with the ability to produce clear, visible colour at irradiated points while maintaining a glossy appearance and protection against scratching and chemical damage.
Implementation Method 1
irradiation of the plastic component from i) and possibly ii) with focussed non-ionising electromagnetic radiation, preferably focussed non-ionising electromagnetic radiation with a wavelength within a range of ≥0.1 μm to ≤1 mm, more preferably within a range of ≥0.15 μm to ≤20 μm, most preferably with laser radiation within a range of ≥0.15 μm to ≤20 μm
Implementation Method 2
The laser beam removes the coating layer and dye simultaneously migrates into the plastic component surface at this point
Data Source
AI summary
The present invention concerns a method for the partial dyeing, in particular for the colour laser engraving, of plastic components, in particular thermoplastic plastic components, more particularly thermoplastic plastic components, comprising a layer construction as well as the resulting partially dyed, preferably colour laser engraved plastic components, in particular thermoplastic plastic components.