Zero-VOC Solvent Ink Composition for Digital Textile Printing
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Solution Overview
Problem
Digital textile printing faces challenges in producing high fidelity process colors on darkly colored fabrics without stiffening the fabric, creating unacceptable surface texture or feel, and emitting volatile organic compounds, which poses health and environmental hazards.
Innovation Solution
Development of digital textile printing inks comprising a pigment, water-dispersible resin particles, and a non-volatile organic compound solvent, with specific properties to ensure inkjet print head compatibility and environmental safety, including a pretreatment agent with a polyvalent metal salt to enhance ink adhesion and prevent ink penetration into the fabric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional volatile organic compound solvents are used in digital textile printing inks, then inkjet print head compatibility and printing performance are improved, but health and environmental hazards increase due to VOC emissions
Solution Approach 1:
The patent changes the chemical parameter of the solvent from volatile organic compounds to non-volatile organic compounds with high boiling points (250°C or greater). This parameter change maintains the ink's functional properties for inkjet printing while eliminating VOC emissions, thereby resolving the contradiction between print head compatibility and environmental safety
Solution Approach 2:
The patent creates an inert environment by using non-volatile solvents that do not evaporate under normal printing and drying conditions. This eliminates the harmful VOC atmosphere that would otherwise be generated, while the solvents maintain their functional role in ink formulation and application
2Strength
If ink penetrates into the fabric during drying, then ink adhesion to fibers is improved, but fabric stiffness and surface texture increase
Solution Approach 1:
The patent applies a pretreatment agent containing polyvalent metal salts to the fabric before printing. This preliminary action creates binding sites on the fabric surface that attract and hold the ink components, ensuring strong adhesion without requiring deep penetration into the fabric structure, thereby maintaining fabric softness
Solution Approach 2:
The pretreatment agent acts as an intermediary between the ink and the fabric. The polyvalent metal salts in the pretreatment create a intermediate layer that provides strong binding sites for the ink components, enabling effective adhesion without direct deep penetration of ink into the fabric fibers
3Reliability
If polymeric binders are used to bond pigments to fibers, then pigment fastness is improved, but ink penetration into fabric increases
Solution Approach 1:
The pretreatment agent is applied before printing to prepare the fabric surface. This preliminary action creates surface binding sites that will capture the ink components upon application, allowing the polymeric binders to bond effectively without needing to penetrate deeply into the fabric structure
Solution Approach 2:
The pretreatment agent serves as an intermediary layer between the fabric and the ink. It provides binding sites that capture the ink components, allowing the polymeric binders to form strong bonds with the fabric surface without requiring deep penetration, thus maintaining pigment fastness while minimizing fabric stiffening
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 provide good hand, feel, and texture to printed textiles with excellent wash fastness and resistance to fading and abrasion, while minimizing environmental impact and health risks by eliminating volatile organic compound emissions.
Implementation Method 1
a non-volatile organic compound solvent having a boiling point of 250° C. or greater
Implementation Method 2
a pretreatment agent with a polyvalent metal salt to enhance ink adhesion
Implementation Method 3
prevent ink penetration into the fabric
Implementation Method 4
water-dispersible resin particles... To bond the pigments to the fibers, polymeric binders are used
Implementation Method 5
These printed colorants should be strongly bound to the fibers... excellent wash fastness and resistance to fading and abrasion
Data Source
AI summary
An ink, having a viscosity of 2.5 to 15 centipoise at 25° C., for textile printing includes pigment; a water dispersible anionic polymeric resin; a water soluble zero volatile organic compound solvent with a boiling point of 250° C. or greater; a crosslinking agent; and water. The water dispersible polymeric resin has particles with a median volume weighted size of less than 150 nm and a 95th percentile volume weighted size of less than 250 nm. The water dispersible polymeric resin has an acid number value of 5 to 40, a resin film elongation of 500 to 1200%, and a film tensile strength of 10 to 60 mPa.