Aqueous Release Coating Composition with Superwetter
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Solution Overview
Problem
Existing aqueous release coating compositions for polymeric film adhesive tapes require high solids content when using water as a carrying liquid, leading to increased weight and cost, and often contain silicone-based release polymers that can transfer to the adhesive, causing defects like 'craters' or 'fisheyes'.
Innovation Solution
Aqueous compositions with non-silicone release polymers and a low level of superwetter, allowing for a homogeneous coating at significantly lower solids content (up to 30-60% reduction) that provides excellent release properties even under high humidity and temperature variations, without using silicone-based polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water is used as a carrying liquid in release coating compositions, then VOC emissions are reduced, but solids content must be increased to 20% (w/w) to ensure coverage, which increases weight and cost
Solution Approach 1:
The patent changes the chemical composition parameters of the release polymer to achieve better water compatibility and coating efficiency. By selecting specific non-silicone polymers with appropriate molecular weights and functional groups, the formulation achieves effective release properties at lower solids content (3-10% range) while maintaining water as the carrying liquid, thus reducing both VOC emissions and final tape weight
Solution Approach 2:
The patent uses composite formulations combining non-silicone release polymers with water-soluble or water-dispersible carriers. This composite approach allows the release agent to be effectively delivered and distributed in aqueous systems without requiring high polymer concentrations, achieving a balance between environmental benefits and weight reduction
2Reliability
If silicone-based release agents are used, then release properties are improved, but silicone transfers to the adhesive causing craters or fisheyes
Solution Approach 1:
The patent extracts and eliminates the silicone component from the release agent formulation while retaining the essential release properties through alternative non-silicone polymers. This extraction prevents silicone transfer to the adhesive layer, eliminating the harmful effect of craters and fisheyes while maintaining effective release characteristics
Solution Approach 2:
The patent employs non-silicone release polymers that are designed to remain on the release liner surface and not transfer to the adhesive. These materials serve their release function effectively and then can be discarded with the liner, preventing contamination of the adhesive while providing reliable release properties
3Area of stationary object
If high solids content (20% w/w) is used in aqueous release coatings, then coverage is ensured, but coating weight and cost increase significantly
Solution Approach 1:
The patent optimizes multiple parameters including polymer molecular weight, functional group density, and formulation composition to achieve effective substrate coverage at reduced solids content. By adjusting these parameters, the formulation maintains adequate coverage and release properties at 3-10% solids content, significantly reducing coating weight and cost
Solution Approach 2:
The patent creates formulations where the release polymer concentrates effectively at the substrate surface during the coating and drying process. This localized concentration ensures adequate coverage and release properties at the critical interface while maintaining lower overall solids content in the bulk coating composition, reducing total coating weight
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 compositions offer effective release and adhesion performance at reduced coating weights, maintaining properties over time and across various substrates and adhesives, while being VOC-free and cost-effective.
Implementation Method 1
these compositions include a low level of superwetter, for example, from more than zero to 2% (w/w, relative to the overall composition). This type of composition can provide a homogeneous coating of release composition even in situations where the solids of the composition is far below that which previously was required in practice.
Implementation Method 2
application of a liquid composition (e.g., emulsion, suspension or dispersion) that includes a film forming polymer and one or more release agents followed by drying
Data Source
AI summary
An aqueous composition that can be used to provide release properties to adhesive tape substrates can be applied at coating weights far less than those required in previously available compositions containing the same or similar release polymers. Inclusion of small amounts of a superwetter results in improved coatability and reduced amounts of sound generated during the process of releasing an adhesive tape from its roll.