Partial Colouring of Plastic Parts Using Dye Ribbon Laser Activation
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Solution Overview
Problem
Existing processes for partial coloring of plastic parts, particularly thermoplastic parts, are complex, resource-intensive, and suffer from poor sharpness and positional accuracy, especially in the context of color laser engraving, and are unsuitable for solvent-sensitive materials.
Innovation Solution
A process involving the application of a color ribbon containing a dye on a plastic part, followed by irradiation with focused nonionizing electromagnetic radiation within a specific wavelength range, allowing precise and intense partial coloring without affecting non-irradiated regions, suitable for both two- and three-dimensional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional printing processes are used for coloring plastic parts, then full-area coverage is achieved, but sharpness and positional accuracy deteriorate
Solution Approach 1:
The colorant is applied to the plastic part before the final shaping or finishing operations. By pre-applying the colorant in the raw state of the part, the process avoids subsequent complex steps of masking, printing, or post-coloring operations that would compromise sharpness or require additional equipment.
Solution Approach 2:
The invention extracts and eliminates the need for complex printing equipment, masks, and multi-step processes. By using a simple application method followed by selective removal or activation, the process achieves high precision without the device complexity of conventional printing systems.
2Adaptability or versatility
If multiple laser sources with different wavelengths are used for color laser engraving, then full-color imaging is achieved, but device complexity and resource consumption increase
Solution Approach 1:
The invention changes the approach from varying laser wavelengths to varying colorant properties. By using a single laser wavelength and different colorants (dyes or pigments) that absorb or reflect different wavelengths of visible light, the process achieves full-color capability without requiring multiple laser sources, thus reducing device complexity while maintaining versatility.
3Ease of manufacture
If conventional coloring processes are used on solvent-sensitive materials, then coloring is achieved, but material degradation occurs
Solution Approach 1:
The invention uses a disposable colorant application medium (such as a foam block or applicator) that is discarded after use. This eliminates the need for reusable tools that would require solvent cleaning, thereby avoiding material degradation from solvent exposure while maintaining ease of manufacture through simple, single-use application methods.
4Manufacturing precision
If inkjet printing is used for color laser printing on moldings, then coloring is achieved, but complete coverage is required initially
Solution Approach 1:
The invention applies colorant only to the specific regions that will be laser-engraved or activated, rather than coating the entire surface. This partial application approach reduces ink consumption significantly while maintaining coloring precision in the targeted areas, avoiding the waste of coating and then removing excess ink from non-target regions.
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
Achieves high-resolution, high-intensity partial coloring with excellent positional accuracy and penetration depth, suitable for solvent-sensitive materials, without requiring multiple laser sources or subsequent solvent washing, and is applicable to security and identification documents.
Implementation Method 1
the dye simultaneously migrates into the plastic surface at this site
Implementation Method 2
The laser beam removes the lacquer layer
Implementation Method 3
irradiating the plastic part (A) from ii) with focused, preferably nonionizing, electromagnetic radiation (C)
Data Source
AI summary
The invention relates to a process for partial colouring, in particular colour laser engraving, of plastic parts, preferably of thermoplastic parts, very particularly preferably of thermoplastic parts comprising a layer construction, comprising the steps of: i) providing a plastic part (A) having at least one surface; ii) laying a colour tape atop at least one portion of the at least one surface of the plastic part (A) to obtain a surface of the plastic part (A) covered with the colour tape; iii) irradiating the plastic part (A) from ii) with focused, preferably nonionizing, electromagnetic radiation (C) on at least one portion of the surface of the plastic part (A) covered with the colour tape, wherein the partial colouring is effected essentially only at the sites on the plastic part (A) irradiated in step iii), wherein the wavelength range of the focused, preferably nonionizing, electromagnetic radiation (C) is in a range from 200 to 20 000 nm, preferably in a range from 300 to 18 000 nm, particularly preferably in a range from 350 to 16 000 nm.