Method for ink jet textile printing
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Solution Overview
Problem
Current inkjet textile printing methods using pigment inks face challenges with ink stability, nozzle clogging, and the need for high-temperature heating to achieve wash fastness and abrasion resistance, particularly when printing on cellulose-based fabrics like cotton.
Innovation Solution
An aqueous inkjet printing method utilizing a polyurethane resin with an anionic group and polyalkylene oxide in the polyester urethane backbone, which enhances dispersibility and adhesion to cellulose fibers, eliminating the need for a heating step and improving storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large amount of binder is added to the ink to improve wash fastness and abrasion resistance, then adhesion to fibres improves, but jetting stability deteriorates and nozzle blocking increases
Solution Approach 1:
The patent changes the chemical parameters of the binder by specifying a polyurethane resin with a glass transition point within -50 to 0°C and specific functional groups. This parameter optimization allows adequate adhesion with minimal binder concentration (0.1-10 wt%), resolving the contradiction between adhesion strength and jetting stability
Solution Approach 2:
The patent creates a composite ink formulation combining pigment particles (0.1-20 wt%), water (70-80 wt%), and polyurethane resin binder (0.1-10 wt%), along with optional co-solvents and surfactants. This composite structure achieves balanced performance where each component contributes to both adhesion and jetting stability
2Strength
If heating above 150°C is applied to fix the binder to fibres for high wash fastness, then adhesion improves, but energy consumption increases and fabric properties may be adversely affected
Solution Approach 1:
The patent changes the glass transition temperature parameter of the binder to within -50 to 0°C, enabling effective adhesion at lower temperatures (60-100°C). This parameter optimization eliminates the need for high-temperature heating while maintaining wash fastness, thereby reducing energy consumption and protecting fabric properties
Solution Approach 2:
The patent replaces the thermal fixation mechanism (high-temperature heating) with a chemical adhesion mechanism based on the polyurethane resin's functional groups and low glass transition point. This substitution achieves equivalent or superior wash fastness without the energy-intensive heating step
3Strength
If binder is introduced in pigment ink to improve fixability, then adhesion to fibres improves, but ink stability on storage deteriorates due to time-related precipitation and flocculation
Solution Approach 1:
The patent optimizes the molecular weight (10,000-1,000,000) and glass transition point (-50 to 0°C) parameters of the polyurethane resin, and specifies functional groups that provide both adhesion and colloidal stability. These parameter changes enable the binder to maintain ink stability during storage while providing adequate fixability to fibres
Solution Approach 2:
The patent introduces water-soluble or water-dispersible polyurethane resin as an intermediary substance that mediates between pigment particles and fabric fibres. This intermediary provides steric and electrostatic stabilization to prevent pigment precipitation and flocculation during storage, while enabling adhesion to fibres during printing
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 method provides high wash fastness and abrasion resistance without the need for high-temperature heating, ensuring long-term stability and reduced nozzle clogging, while maintaining excellent print quality on cellulose-based fabrics.
Implementation Method 1
an aqueous inkjet printing method utilizing a polyurethane resin with an anionic group and polyalkylene oxide in the polyester urethane backbone, which enhances dispersibility and adhesion to cellulose fibers
Data Source
AI summary
An ink jet printing method comprising the jetting an aqueous ink jet ink onto a fabric containing cellulose fibres followed by a drying step, the ink jet ink comprises a polyurethane resin having an anionic group and a polyalkylene oxide in a side chain thereof, wherein the polyurethane resin is obtainable by reacting a polyester polyol, a polyether diol, a polyol or amine containing an anionic group and a polyisocyanate, and wherein the polyester polyol is obtained by reacting an aromatic polycarboxylic acid and a polyol.