Decorated Natural Leather Laser Ablation Bleaching

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Solution Overview

Problem

Current methods for manufacturing decorated natural leather are labor-intensive and costly, particularly when it comes to personalization and customization, with existing digital printing technologies often resulting in inferior quality due to issues like image quality, light fading, and scratch resistance.

Innovation Solution

A method involving laser ablation and bleaching of a base coat on dyed crusted leather, followed by the application of a polymeric layer and UV curable pigmented inkjet inks, which includes a high percentage of monofunctional monomers or oligomers for enhanced flexibility and light fastness, and a protective top coat for improved durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If UV curable pigmented inks are jetted directly onto tanned leather, then high quality decorated leather can be obtained, but the cured ink layer exhibits cracks after extensive flexing

Engineering Contradiction:
Improveimage qualityVSAvoidflexing resistance
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the UV curable ink by incorporating at least 60 wt% monofunctional monomers or oligomers, which have lower cross-linking density and better flexibility compared to traditional multifunctional monomers. This parameter change allows the ink layer to maintain image quality while resisting cracking during flexing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining monofunctional monomers/oligomers with pigments and photoinitiators. This composite material structure provides both the desired image quality from the pigments and the flexing resistance from the monofunctional polymer matrix, resolving the contradiction between quality and durability.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If hybrid solvent/radiation curable inks with high organic solvent content are used, then the ink can be applied to leather, but image quality deteriorates due to excessive spreading

Engineering Contradiction:
Improveink applicationVSAvoidimage quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the solvent content parameter by using solvent-free UV curable inks, eliminating the excessive spreading issue caused by high organic solvent content while maintaining ease of application through the curable nature of the ink formulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies the ink in a controlled manner where the liquid ink is jetted onto specific areas of the leather and then cured in place with UV light. This local application and curing approach prevents excessive spreading while ensuring complete coverage of the desired areas.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If screen printing is used to decorate leather, then decoration can be achieved, but the process becomes labour intensive and costly for personalization

Engineering Contradiction:
Improvedecoration capabilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces the mechanical screen printing system with a digital inkjet printing system. This substitution eliminates the need for physical screens and manual processes, enabling direct digital printing of customized designs onto leather, thereby dramatically improving productivity and reducing labor costs while maintaining decoration quality.

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

Solution Approach 2:

The patent changes the manufacturing process from batch-oriented screen printing to continuous digital inkjet printing. This parameter change in the manufacturing approach allows for efficient personalization and customization without the setup time and labor requirements of traditional screen printing methods.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If inkjet printing with heat transfer paper is used, then printing can be performed on leather, but the transferred dyes exhibit light fading and scratch resistance issues

Engineering Contradiction:
Improveprinting capabilityVSAvoidlight fastness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the heat transfer printing mechanism with direct UV curable inkjet printing. This substitution eliminates the heat transfer process that causes dye degradation and fading, while directly depositing and curing pigmented ink onto the leather surface for superior light fastness and scratch resistance.

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

Solution Approach 2:

The patent changes the curing mechanism from thermal curing (heat transfer) to photopolymerization curing (UV light). This parameter change in the curing process prevents thermal degradation of the ink and substrate, resulting in improved light fastness and durability of the printed image.

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 method allows for high-quality, personalized, and customizable decorated leather with improved flexing properties and light fastness, reducing the costs associated with labor and material usage while maintaining the luxury aspect of the leather.

Implementation Method 1

a) laser ablating part of a base coat on dyed crusted leather

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

b) bleaching the laser ablated part with a bleaching agent

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

inkjet printing a colour image (43) on the base coat (44) using one or more pigmented UV curable inkjet inks

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3666909B1Decorated natural leather
Publication Date: 2021.10.13 AGFA NV
  • EP3666909B1 patent drawingFigure 1
  • EP3666909B1 patent drawingFigure 2
  • EP3666909B1 patent drawingFigure 3

AI summary

A manufacturing method of decorated natural leather including the steps of: a) laser ablating part of a base coat on dyed crusted leather; and b) bleaching the laser ablated part with a bleaching agent.