Ink Composition Adhesion to Polypropylene via Siloxane Surfactant
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Solution Overview
Problem
Existing ink compositions for continuous inkjet printing have poor adhesion to low surface energy substrates such as polypropylene, HDPE, and LDPE due to the presence of siloxane surfactants and metal conductivity salts, which are expected to hinder adhesion.
Innovation Solution
An ink composition with a siloxane surfactant present at least 0.3% by weight, comprising a polyether modified siloxane surfactant, and a metal conductivity salt, resulting in improved adhesion to low surface energy substrates by maintaining conductivity below 500 µS/cm without the metal conductivity salt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a siloxane surfactant is added to the ink composition to regulate surface tension, then the ink composition can be used for continuous inkjet printing, but the adhesion to low surface energy substrates deteriorates
Solution Approach 1:
The patent changes the concentration parameter of the siloxane surfactant from typical low levels (0.01-0.1%) to a higher level (0.3-5.0%), which fundamentally alters the ink's surface properties and interaction with substrates, resolving the adhesion problem while maintaining printing capability
Solution Approach 2:
The patent creates a composite ink formulation by combining siloxane surfactant with specific co-surfactants (such as fluorinated surfactants or alkyl polyglucosides) in defined ratios, where the components work synergistically to achieve both continuous inkjet printing and improved adhesion to low surface energy substrates
2Reliability
If a metal conductivity salt is added to the ink composition to provide sufficient electrical conductivity, then continuous inkjet printing is enabled, but the adhesion to low surface energy substrates deteriorates
Solution Approach 1:
The patent optimizes the concentration parameter of the metal conductivity salt to a specific range (0.1-5.0%) that provides sufficient electrical conductivity for continuous inkjet printing while minimizing the detrimental effect on adhesion to low surface energy substrates
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 ink composition achieves good adhesion to low surface energy substrates, contrary to expectations, producing durable printed images on materials like polypropylene, HDPE, and LDPE, and is compatible with continuous inkjet printers.
Implementation Method 1
The siloxane surfactant is stated to be for the purpose of modifying and regulating the surface tensions of the ink compositions
Implementation Method 2
where these components would not provide sufficient electrical conductivity for continuous inkjet printing, a metal conductivity salt
Data Source
Figure 1~1B
AI summary
This application relates to an ink composition, in particular an ink composition for use in continuous inkjet printing. The ink composition for use in continuous inkjet printing, contains a siloxane surfactant and a metal conductivity salt. The ink composition is suitable for producing printed images with good adhesion to low surface energy substrates, in particular, low energy substrates such as polypropylene, LDPE and HDPE. The ink composition has a liquid carrier, a colourant, a siloxane surfactant and a metal conductivity salt. The siloxane surfactant is present in an amount greater than 0.1% by weight of the ink composition.