Sulfonated Polyester Ink for Digital Offset Printing
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Solution Overview
Problem
Current digital offset printing inks face challenges in achieving high viscosity and tack stability across varying temperatures, which affects ink transfer efficiency and cohesion, especially in digital offset lithography systems where high viscosity is required for effective imaging and substrate transfer.
Innovation Solution
The development of an ink composition comprising water, an optional co-solvent, a sulfonated polyester with a degree of sulfonation between 3.5 and 7.5 mole percent, and a polyurethane dispersion, which enhances viscosity and adhesiveness, allowing for improved ink transfer and cohesion at different temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher viscosity is used to improve ink transfer to substrate, then transfer efficiency improves, but ink delivery from anilox roller to blanket deteriorates at low temperatures
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the ink - specifically using sulfonated polyester with controlled degree of sulfonation (3-15 mole percent) and molecular weight (5,000-50,000), along with polyurethane dispersion (5-30 weight percent), to achieve viscosity values that enable both low-temperature ink delivery and high-temperature transfer efficiency
Solution Approach 2:
The patent uses composite materials by combining sulfonated polyester with specific chemical structure (containing aromatic rings and sulfonate groups) and polyurethane dispersion in controlled ratios, creating an ink formulation that exhibits both flowability at low temperature and high viscosity/stability at operating temperature
2Reliability
If higher viscosity is used to improve ink cohesion, then transfer stability improves, but ink loading and distribution deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight of sulfonated polyester (5,000-50,000) and the degree of sulfonation (3-15 mole percent), along with polyurethane dispersion content (5-30 weight percent), to achieve optimal balance between ink cohesion for stable transfer and fluidity for proper loading and distribution in the printing system
Data Source
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AI summary
An aqueous ink composition including water, an optional co-solvent, a sulfonated polyester, and a polyurethane dispersion, and process of making thereof.