Process for the surface treatment of plastic objects

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Solution Overview

Problem

Current methods for coloring 3D printed plastic objects are limited to only black and white, and existing coloring techniques often result in paint that is prone to flaking off, affecting the aesthetics of the molded parts.

Innovation Solution

A method involving a dyeing mixture of metal complex, acid, reactive, azo, or disperse dyes dissolved in a solvent, applied at controlled temperatures, combined with surface blasting and impregnation using a polymer-based solution to ensure durable color adherence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If painting is used to color plastic moldings, then color variety is improved, but paint adhesion and durability deteriorate (paint flakes or chips easily)

Engineering Contradiction:
Improvecolor varietyVSAvoidpaint adhesion
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the mechanical painting process with a chemical dyeing process. Instead of applying paint mechanically that adheres poorly to plastic surfaces, the invention uses dye solutions that chemically penetrate and bond with the plastic material through heating, substituting a mechanical application method with a chemical absorption method to achieve superior adhesion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the temperature parameter during the coloring process by heating the plastic moldings to above their glass transition temperature. This parameter change enables the plastic to absorb the dye more effectively and ensures durable color retention, resolving the adhesion problem while maintaining color variety.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple painting steps are used to ensure color adherence, then color retention is improved, but process complexity increases

Engineering Contradiction:
Improvecolor retentionVSAvoidnumber of painting steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate operations (surface preparation, heating, dye application, and setting) into a single integrated dyeing bath process. The plastic moldings are placed in a heated dye solution that simultaneously prepares the surface, applies the color, and bonds it in one continuous operation, eliminating the need for multiple sequential painting steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes the phase transition of the plastic material by heating it above its glass transition temperature during the dyeing process. This thermal phase transition enables the plastic to absorb and retain the dye more effectively, achieving durable color retention through a single process rather than multiple steps.

Inventive Principle:
Principle #36Phase transitions

3Ease of manufacture

If conventional dyeing methods are used on 3D printed plastic objects, then color application is simplified, but color penetration and uniformity deteriorate

Engineering Contradiction:
Improvecoloring process simplicityVSAvoidcolor uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the temperature of the dyeing solution and the duration of the dyeing process. By heating the dye solution to specific temperatures and maintaining it for optimized time periods, the plastic objects achieve uniform color penetration throughout, transforming a simple surface application into a controlled penetration process that ensures uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces simple surface-level dye application with a thermally activated penetration process. Instead of merely coating the surface, the heated dye solution penetrates into the plastic material, ensuring uniform color distribution throughout the object while maintaining process simplicity through a single bath operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables coloring of 3D printed plastic objects in a wide range of colors with improved color retention, preventing flaking and ensuring a uniform, long-lasting finish.

Implementation Method 1

the coloring process is carried out at a temperature which is above the glass transition temperature of the plastic parts to be colored, so that the color can penetrate into the plastic parts

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The fibers are placed in a dyeing solution, which may contain from 0.01% to 0.2% by weight of an acid dye, and which is heated to a temperature of between 60°C and 100°C for a specified period of time

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

the surface of the plastic objects are impregnated using a polymer-based impregnating solution for the impregnation

Methodology Applied
Scientific EffectImpregnation: Capillary Action

Data Source

PatentEP3107957B1Process for the surface treatment of plastic objects
Publication Date: 2021.12.22 DYEMANSION

AI summary

The invention relates to a method for treating surfaces of plastic objects, wherein in a dying step - a mixture of dyes is produced, wherein a dye (e.g. a metal complex dye) is dissolved in a solvent, wherein between 0.05 g and 50 g of the dye is added to each liter of solvent - the dye mixture is heated to a dying temperature of between 60 °C and 180 °C and - the plastic objects are placed in the heated dye mixture for a period of between 5 minutes and 6 hours for dying. The invention further relates to a plastic object, in particular a polyamide-molded part, wherein the surface of the plastic object is treated with the method according to the invention. The plastic objects are preferably manufactured by a 3D-printing method.