Reactive Azo Dye Compounds for Neutral Single-Bath Blend Dyeing
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Solution Overview
Problem
Coloring natural or regenerated cellulosic fibers in blends with synthetic fibers, such as polyester, is challenging due to different dyeing conditions required for disperse and reactive dyes, particularly the need for highly alkaline conditions that are unsuitable for disperse dyes.
Innovation Solution
Development of compounds with specific formulas that allow for simultaneous dyeing of cellulosic and polyester fibers under neutral pH conditions, using a combination of reactive and disperse dyes, which include organic residues from monoazo, disazo, anthraquinone, triphendioxazine, or metal phthalocyanine dyes, and fibre reactive groups, enabling a wider and deeper color range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If highly alkaline conditions are used for reactive dyes on cellulosic fibres, then the dyeing of cellulosic fibres is effective, but the polyester fibres cannot be coloured with disperse dyes under these conditions
Solution Approach 1:
The patent modifies the chemical structure of reactive dyes by introducing specific functional groups (sulfonate groups and heterocyclic rings) that enable the dye to function effectively at neutral pH levels, allowing simultaneous dyeing of both cellulosic and polyester fibres without requiring highly alkaline conditions
Solution Approach 2:
The invention creates a composite dye system that combines characteristics of both reactive dyes (for cellulosic fibres) and disperse dyes (for polyester fibres) into a single molecular structure, enabling dual-functionality in a single-bath dyeing process
2Reliability
If conventional reactive dyes are used for cellulosic fibres, then good fastness is achieved, but the colour range is limited when dyeing blends with polyester fibres
Solution Approach 1:
The patent designs reactive dye molecules with multiple functional groups that provide both the fastness properties needed for cellulosic fibres and the colour variety needed for polyester fibres, making the dye system universally applicable to both fibre types with enhanced colour range
3Manufacturing precision
If separate dyeing processes are used for polyester and cellulosic fibres, then each fibre type can be optimally coloured, but the manufacturing complexity and time increase
Solution Approach 1:
The patent merges the functionality of separate reactive and disperse dyeing processes into a single-bath, single-stage dyeing process by creating reactive dye molecules that can simultaneously interact with both cellulosic and polyester fibres under the same neutral pH conditions
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 compounds provide deep and vibrant color shades with excellent fastness properties on cellulosic textiles, including cotton, viscose, and lyocell, under neutral fixation conditions, achieving a range of colors from yellow to navy with improved wet and all-round fastness.
Implementation Method 1
where Z is a fibre reactive group... -SO2-Y or -NHCO(CH2)a- SO2-Y, -CONH(CH2)b-SO2-Y
Implementation Method 2
adding a diazonium salt to the second reaction product... D and D1 are organic residues, which may be the same or different, and may be residues of monoazo, disazo
Data Source
AI summary
A compound having the formula as shown in Formula (1), where each of R1, R2, R3 is H or an alkyl group; X is nitrogen or C-B where B is H, Cl or a methyl group; D and D1 are organic residues, which may be the same or different; and E is an organic residue or a group of the formula of Formula (2), where R4, R5 are each hydrogen, methyl, methoxyl or SO3H, is useful in colouring cellulosic fabrics, and may be used to colour blends of cellulosic fibres with fibres such as polyester which are dyed using disperse dyes in a single-bath, single-stage operation.