Non-aqueous UV/led digital inks for printing flexibile materials
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Solution Overview
Problem
Current digital inks for printing on flexible materials, such as fabrics and hides, suffer from reduced flexibility and elasticity, high water and energy consumption, and lack of ecological and economic efficiency, while also failing to provide excellent colour fastness to rubbing.
Innovation Solution
The use of non-aqueous digital UV/LED inks comprising at least 75% monofunctional acrylic monomers with low viscosity and specific glass transition temperatures, combined with a curing process using UV/LED and optionally excimer lamps, ensures flexibility and adhesion without compromising material properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If aqueous inks are used for printing on textiles, then acceptable hand and flexibility of the printed fabric are obtained, but considerable and expensive waste of water and energy occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by using non-aqueous formulations with specific monomer ratios (at least 70% THFA and at least 20% total monofunctional acrylic monomers) and controlled Tg (≤5°C), enabling the ink to achieve flexibility without requiring water-based formulations that demand high energy for drying and water management infrastructure
Solution Approach 2:
The patent replaces the water-based drying mechanism with UV/LED photopolymerization curing. This substitution eliminates the need for thermal drying processes and water evaporation, dramatically reducing energy consumption while maintaining the flexibility benefits previously only achievable with aqueous systems
2Ease of manufacture
If non-aqueous digital UV inks containing prepolymer with epoxy nature are used, then printing on textile materials becomes possible, but the printed fabrics have absolutely unacceptable or even zero flexibility
Solution Approach 1:
The patent fundamentally changes the chemical parameters by eliminating epoxy prepolymers and using instead a specific composition of monofunctional acrylic monomers (≥70% THFA and ≥20% total monofunctional content) with controlled Tg ≤5°C. This parameter change enables the ink to cure properly on textiles while maintaining excellent flexibility, resolving the contradiction between printability and fabric softness
Solution Approach 2:
The patent creates a composite ink formulation combining multiple monofunctional acrylic monomers (THFA, CTFA, TMCHA, LA, CA, VMOX) in specific ratios, along with photoinitiators and pigments. This composite material approach allows optimization of both curing performance on textiles and flexibility, achieving properties that individual components cannot provide alone
3Ease of manufacture
If non-aqueous digital UV inks containing oligomer are used, then printing on fabric is achieved, but satisfactory flexibility is not obtained
Solution Approach 1:
The patent changes the molecular structure parameter by using exclusively monofunctional monomers instead of oligomers. The specified monomer composition (at least 70% THFA and at least 20% total monofunctional acrylic monomers with Tg ≤5°C) ensures that the cured film remains flexible while maintaining adequate adhesion to fabric substrates
Solution Approach 2:
The patent applies local quality by ensuring the ink formulation provides different properties at different scales: at the molecular level, monofunctional monomers provide flexibility; at the macro level, the cured film provides adequate adhesion. This local optimization resolves the contradiction between fabric bonding and flexibility
4Reliability
If non-aqueous digital UV inks with high Tg are used for leather printing, then good characteristics are obtained, but flexibility of the material is reduced in an absolutely unacceptable way
Solution Approach 1:
The patent changes the glass transition temperature parameter from high Tg (as used in leather printing applications) to low Tg (≤5°C, preferably -20°C to 0°C) by using specific monofunctional acrylic monomers. This parameter change enables the ink to provide reliable adhesion and characteristics while maintaining acceptable flexibility for textile applications
5Ease of operation
If inks containing THFA are used with higher contents, then flexibility is improved, but curability and polymerizability of the printed coating film are reduced
Solution Approach 1:
The patent optimizes the concentration parameter of THFA to at least 70% by weight while maintaining curability through the synergistic effect of multiple photoinitiators and the specific presence of at least 20% total monofunctional acrylic monomers. This balanced composition achieves both high flexibility and adequate curability
Solution Approach 2:
The patent uses a composite photoinitiator system and combines multiple monofunctional acrylic monomers in specific ratios. This composite approach ensures that even with high THFA content (≥70%), the ink maintains sufficient polymerizability and curability while achieving the desired flexibility
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
The inks maintain high flexibility and elasticity, provide excellent colour fastness to rubbing, and reduce environmental impact, while being odorless and safe, with improved printing quality and efficiency.
Implementation Method 1
curing the ink-printed flexible material, by exposing the latter to a UV/LED lamp
Implementation Method 2
exposing the printed flexible material under an excimer lamp, before exposing it under the UV/LED lamp
Data Source
AI summary
The use of non-aqueous digital UV/LED inks for printing a flexible material is disclosed, especially for printing fabrics and hides. Moreover, an improved process is disclosed for digitally printing on flexible materials, by using said non-aqueous digital UV and/or LED inks. The resulting printed flexible materials are soft and matt, with an excellent colour fastness to rubbing, while still conveniently maintaining the initial flexibility. Moreover, it should be appreciated that resulting printed flexible materials are also completely odourless, differently from the materials printed according to the prior art.