Inkjet Paper Coating With Sulfate Salts for Lower Chloride Corrosion
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Solution Overview
Problem
High concentrations of calcium chloride in paper milling operations lead to corrosion of equipment and reduced lifespan of non-stainless steel parts, while maintaining satisfactory print quality with pigmented inks is challenging, especially in closed-loop mills with low fresh water consumption.
Innovation Solution
A surface treatment composition combining sulfate ions with calcium chloride as colorant fixatives, reducing calcium chloride loading by half or more, and using sulfate salts like calcium sulfate or sodium sulfate to enhance print quality and control corrosivity, while maintaining or improving optical density and ink dry time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high concentration of calcium chloride is used to enhance print quality, then optical density and ink dry time are improved, but equipment corrosion increases
Solution Approach 1:
The patent changes the chemical composition parameters by replacing chloride ions with sulfate ions (using calcium sulfate, sodium sulfate, or magnesium sulfate instead of calcium chloride). This parameter substitution maintains the colorant fixative function while eliminating the corrosive effect, as sulfate salts do not promote corrosion of paper milling equipment
Solution Approach 2:
The patent uses sulfate salts as a substitute that serves the same functional purpose (colorant fixative) but without the harmful long-term effects of chloride salts. The sulfate-based system can be used without concern for cumulative corrosion damage to equipment, effectively replacing a harmful substance with a benign alternative
2Manufacturing precision
If calcium chloride loading is increased to maintain print quality in closed-loop mills, then image quality is improved, but corrosion resistance of equipment deteriorates
Solution Approach 1:
The patent fundamentally changes the chemical parameter from chloride-based to sulfate-based colorant fixatives. This parameter change allows closed-loop mill operations to maintain image quality without the reliability issue of equipment corrosion, since sulfate salts do not have the same corrosive effects as chloride salts on metal equipment
3Manufacturing precision
If calcium chloride is used as colorant fixative, then pigment colorant adhesion is improved, but lifespan of non-stainless steel parts is reduced
Solution Approach 1:
The patent replaces chloride-containing fixatives with sulfate-based alternatives that achieve the same pigment adhesion function without the harmful side effect of reducing equipment lifespan. The sulfate salts serve as effective colorant fixatives but do not cause the same degree of corrosion and equipment degradation
4Manufacturing precision
If conventional calcium chloride treatment is used, then print quality is maintained, but chloride content in treatment composition is high
Solution Approach 1:
The patent extracts and removes the harmful chloride component from the colorant fixative system while retaining the essential functionality. By using sulfate salts (calcium sulfate, sodium sulfate, or magnesium sulfate) instead of chloride salts, the invention eliminates chloride content from the treatment composition while maintaining effective pigment colorant fixation and print quality
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 sulfate-chloride combination achieves superior print quality comparable to conventional calcium chloride systems with reduced equipment corrosion risk and lower exothermic potential, allowing for reduced fresh water consumption in paper mills.
Implementation Method 1
Sulfate ions interact with anionic pigments, and in this way the pigment colorant is made to stay on the outermost portion or surface of the print media
Implementation Method 2
Calcium ions interact with anionic pigments, and in this way the pigment colorant is made to stay on the outermost portion or surface of the print media, which increases the optical density of the image on the media
Implementation Method 3
such high loadings of chloride-containing compounds can promote corrosion of the paper milling equipment used to produce the print media
Data Source
AI summary
An inkjet printable media comprises a paper base containing a surface coating comprising calcium chloride and a synergistic amount of a sulfate salt. When the printable media is printed with an inkjet ink containing a black pigment, a KOD value of the printed media is equal to or greater than that of a comparative inkjet printed media comprising up to 12 kg calcium chloride/T media and lacking the sulfate salt.