Metal-Free Textile Dyes for Higher NIR Reflectance
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Solution Overview
Problem
Existing textile materials, especially those dyed for aesthetic or technical reasons, tend to absorb and retain heat due to solar radiation, leading to discomfort, and conventional NIR-reflecting coatings often contain metal particles that compromise wearing comfort and handle.
Innovation Solution
Dyeing textile materials with metal-free dyes that maintain or increase Near Infrared (NIR) reflectance in the 700 nm to 1100 nm range using customary dyeing processes, specifically using acid, basic, disperse, or reactive dyes with defined structures, to minimize heat absorption without affecting the material's comfort or handle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional coatings with metal particles are used to reflect thermal radiation, then NIR reflectance is improved, but wearing comfort and handle deteriorate
Solution Approach 1:
The invention extracts and eliminates metal particles from the coating composition, retaining only the binder system that provides NIR reflection. This removes the harmful component (metal particles affecting comfort) while preserving the useful function (NIR reflection through binder).
Solution Approach 2:
The invention changes the chemical composition parameters of the coating by selecting specific binder systems with appropriate NIR reflection properties and eliminating metal particle additives. This parameter change achieves NIR reflection without the negative effects of metal particles on wearing comfort.
2Illumination intensity
If dark coloured textile materials are used for aesthetic reasons, then appearance is improved, but heat absorption increases
Solution Approach 1:
The invention applies local quality by differentiating the optical properties at different wavelengths: the dye provides absorption in the visible range (aesthetic appearance) while the binder system provides reflection in the NIR range (heat reflection). This local differentiation of optical properties resolves the contradiction between appearance and heat absorption.
Solution Approach 2:
The invention creates a composite optical system where the dyed textile material combines dye molecules (for visible color) with a NIR-reflecting binder system. This composite structure enables simultaneous achievement of aesthetic appearance through dye and heat reflection through the binder.
3Loss of energy
If metal-containing coatings are applied to reduce solar absorption, then thermal radiation reflection is improved, but textile handle and comfort deteriorate
Solution Approach 1:
The invention extracts metal particles from the coating formulation, relying solely on the binder system to provide thermal radiation reflection. This extraction eliminates the harmful effect on textile handle while maintaining the energy reflection function.
Solution Approach 2:
The invention replaces expensive and harmful metal particles with an organic binder system that achieves the same functional effect (NIR reflection) without the negative side effects. The binder acts as a temporary coating that provides the needed protection without compromising textile properties.
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 process effectively reduces heat absorption, enhancing wearing comfort by maintaining or increasing NIR reflectance, thus reducing thermal radiation absorption, while preserving the textile's properties and comfort.
Implementation Method 1
dyed textile materials having, compared with the same, undyed textile materials, an increased or at least equivalent reflectance of electromagnetic radiation in the near infrared (NIR), in particular dyed textile materials having increased or at least equivalent reflectance of electromagnetic radiation in the region of electromagnetic radiation of wavelength 700 nm to 1100 nm
Data Source
AI summary
Use of the customary dyes for the type of fibre in question and using the customary dyeing and/or printing processes for the type of fibre in question for minimally reducing, retaining or increasing the NIR reflectance, preferably increasing the NIR reflectance, in the region of electromagnetic radiation of wavelength 700 nm to 1100 nm of textile material in relation to the undyed and untreated textile material, characterized in that metal-free dyes are used.