Piezo-jettable Varnish Composition for Corrugated Board Protection
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Solution Overview
Problem
Existing overprint varnishes require analogue printing and curing processes, which complicate and increase the cost of inkjet printing, and UV-curable varnishes pose environmental concerns, while analogue coating techniques can hinder glueability of printed materials like corrugated boards.
Innovation Solution
Development of aqueous jettable overcoat varnishes with high solid content, comprising a latex polymer, polymeric salt, water, and a co-solvent, allowing selective application using a piezo printhead to achieve desirable varnish performance, decap performance, and film formation without additional heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV-curable overprint varnishes are used, then print protection and durability are improved, but environmental harm increases due to UV curing requirements and harmful emissions
Solution Approach 1:
The patent changes the chemical composition parameters of the varnish by using aqueous latex polymer dispersions with specific molecular weights and compositions, eliminating the need for UV-curable chemistry while maintaining protective功能的实现
Solution Approach 2:
The patent converts the traditionally harmful UV curing process into a beneficial ambient-drying process, where the varnish cures naturally at room temperature without harmful emissions, turning an environmental hazard into an eco-friendly solution
2Ease of manufacture
If analogue coating techniques are used, then varnish application is achieved, but glueability of printed materials deteriorates
Solution Approach 1:
The patent applies varnish selectively only to areas requiring protection through digital inkjet printing, leaving other areas of the substrate free of varnish coating, thereby preserving glueability in non-varnished regions while providing protection where needed
Solution Approach 2:
The patent uses partial coating action by applying varnish only to specific areas rather than coating the entire substrate, achieving sufficient protection without excessive varnish application that would compromise glueability
3Reliability
If existing varnish compositions are used, then print protection is achieved, but process complexity increases due to additional heating and curing steps
Solution Approach 1:
The patent extracts and eliminates the heating and UV curing steps from the traditional varnishing process, using a composition that dries and cures ambiently, thereby simplifying the overall printing process while maintaining protective功能
Solution Approach 2:
The varnish composition is formulated to self-dry and self-cure at ambient temperature without requiring external heating or UV irradiation equipment, making the process self-sufficient and eliminating complex additional processing steps
4Reliability
If high solid content varnish is used, then film formation and durability are improved, but jetting performance deteriorates due to viscosity issues
Solution Approach 1:
The patent optimizes the molecular weight parameters of the latex polymer and polymeric salt components, and adjusts their ratio to achieve a balance where high solid content formulation maintains adequate jetting performance while ensuring proper film formation and durability
Solution Approach 2:
The patent uses a composite aqueous system combining latex polymer, polymeric salt, water, and co-solvent in specific proportions, creating a multi-component formulation that achieves both high solid content for good film formation and appropriate viscosity for jetting performance
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 aqueous varnish compositions provide excellent decap performance, durability, and film formation at ambient temperature, enabling cost-effective, environmentally preferable, and high-quality protection of printed images without additional heating or curing, while maintaining glueability of substrates.
Implementation Method 1
The actuator includes a piezoelectric material which deforms when an electrical voltage is applied. As such, when the piezoelectric material deforms, the flexible membrane deflects thereby causing ejection of fluid (e.g. varnish composition) from the fluid chamber and through an orifice communicated with the fluid chamber.
Data Source
AI summary
Herein is described a piezo-jettable varnish composition comprising a latex polymer having a weight averaged molecular weight Mw of greater than about 50 000, a polymeric salt derived from an acidic polymer having a weight averaged molecular weight Mw in the range of about 1000 to about 50 000, water, and a co-solvent, wherein, the latex polymer and polymeric salt are present in amounts such that the ratio of latex polymer to polymeric salt by weight is in the range of greater than about 1:1 to about 8:1.