Inkjet Polymer Particle Formation for Rough Coatings

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Solution Overview

Problem

Existing methods for producing polymeric coatings using inkjet technology face limitations in particle size and distribution, leading to uneven coatings and restricted material selection due to nozzle clogging and the need for additional binders, which hinders the achievement of diverse surface and mechanical properties.

Innovation Solution

The method involves using an inkjet print head to eject fluid preparations that partially cure during flight, forming polymeric particles with adjustable size and distribution, eliminating the need for solids and allowing for in situ particle generation, thereby enabling the production of rough, polymeric coatings with tailored properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If particles are applied to substrate using conventional inkjet methods, then coating is formed, but nozzle clogging occurs and particle size is limited

Engineering Contradiction:
Improveparticle size controlVSAvoidnozzle clogging
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by curing the polymeric material during flight before particle formation. The fluid preparation is ejected and partially cured in flight, forming stable polymeric particles that cannot clog nozzles. This preliminary curing action prevents the nozzle clogging problem that would occur if uncured particles were attempted to be deposited.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical particle handling system with a chemical/photonic system. Instead of mechanically transporting and depositing pre-formed particles (which causes clogging), the system uses photopolymerization to transform fluid preparation into particles during flight. This substitution of mechanical particle manipulation with light-induced chemical transformation eliminates nozzle clogging.

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

2Adaptability or versatility

If additional binders are used to achieve diverse surface properties, then coating adhesion improves, but material selection freedom decreases

Engineering Contradiction:
Improvesurface property diversityVSAvoidcoating formulation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by making the polymeric material itself multi-functional. The same photopolymerizable fluid preparation provides both adhesion (through curing to substrate) and diverse surface properties (through particle morphology control). No separate binders are needed because the polymeric material performs all functions, simplifying the coating formulation while maintaining versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts and eliminates the need for additional binders from the coating formulation. By using photopolymerizable materials that form particles during flight, the system removes the separate binder component that would otherwise be required for adhesion. This extraction of unnecessary components reduces formulation complexity while maintaining coating performance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If uniform particle distribution is achieved, then coating homogeneity improves, but particle size flexibility decreases

Engineering Contradiction:
Improvecoating uniformityVSAvoidparticle size range
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the particle formation process dynamic and controllable during flight. The photopolymerization occurs dynamically as droplets traverse the illumination zone, allowing real-time control of particle properties. By adjusting flight time, illumination intensity, and droplet velocity, the system dynamically controls particle size while maintaining uniform distribution through the inherent randomness of droplet ejection patterns.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by controlling multiple process parameters to achieve both uniformity and size flexibility. By independently adjusting droplet size, illumination intensity, flight time, and substrate distance, the system can produce particles of various sizes while maintaining uniform spatial distribution. The key parameter change is the degree of curing during flight, which controls particle morphology without affecting distribution uniformity.

Inventive Principle:
Principle #35Parameter changes

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 approach allows for the creation of polymeric particles with controlled size and distribution, enabling the production of rough coatings with enhanced mechanical and aesthetic properties, such as improved scratch resistance and optical effects, while avoiding nozzle clogging and reducing the need for additional binders.

Implementation Method 1

The inkjet printhead has at least one nozzle with which the fluid preparation for processing with inkjet nozzles is ejected as fluid droplets in response to electrical signals

Methodology Applied
Scientific EffectElectrical signals control droplet ejection: Electromechanical Film

Implementation Method 2

radiation is shone into the area between the printhead and the substrate, so that the droplets are at least partially hardened by the radiation during their flight time

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 3

The fluid preparation comprises at least one photoinitiator. The light source is arranged such that the light emitted by the light source cures the droplets at least partially during flight

Methodology Applied
Scientific EffectLight hardening: Photopolymerisation

Implementation Method 4

The spherical shape results from the surface tension of the droplets

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP3068551B1Production of polymer particles and rough coatings by means of inkjet printing
Publication Date: 2023.03.15 ACTEGA SCHMID RHYNER AG
  • EP3068551B1 patent drawingFigure 1~2
  • EP3068551B1 patent drawingFigure 3~6
  • EP3068551B1 patent drawingFigure 7~9

AI summary

The invention relates to a method for producing polymer particles in which, in response to electrical signals, by means of an inkjet print head having at least one nozzle, a fluid preparation for processing by means of inkjet nozzles is expelled from the nozzle in the form of droplets and, by means of a radiation source, radiation is aimed at the droplets in flight, wherein the fluid preparation for processing by means of inkjet nozzles at least partly hardens under the action of the radiation, such that particles are obtained from the fluid droplets before interception or impingement. The fluid preparation for processing by means of inkjet nozzles comprises at least one representative from the group comprising pre-polymers and/or oligomers and/or monomers and/or reactive thinners and at least one photoinitiator, the representative from the first class of compounds having at least one first polymerizable group which can be radically polymerized. The invention further relates to a printed product comprising a printed or printable substrate or carrier material having a rough polymer coating, wherein the coating is formed by spherical or largely spherical polymer particles, and to a device for producing a corresponding printed product.