Urethane Coating for Printed Substrates Without Lamination
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Solution Overview
Problem
Existing methods for protecting printed images on plastic surfaces, such as lamination with clear plastic films, add complexity and cost to the manufacturing process and do not provide sufficient abrasion resistance, high-temperature resistance, and chemical resistance.
Innovation Solution
A process involving a printed substrate coated with a urethane coating composition formed by combining a polyisocyanate prepolymer and a polyol, where the isocyanate index is greater than 0.9, applied to the printed surface to create a durable cured polyurethane layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a covering clear plastic film is attached to the printed surface by lamination, then the printed image is protected from damage and distortion, but the manufacturing process complexity and cost increase
Solution Approach 1:
The patent combines the protective coating and the printed substrate into a single integrated structure. The urethane coating is applied directly to the printed surface and cured to form a bonded protective layer, eliminating the need for separate lamination of clear plastic films. This merging of functions reduces manufacturing steps while maintaining protection.
Solution Approach 2:
The patent uses a composite material system consisting of a polyisocyanate prepolymer and a polyol that react to form a cured urethane coating. This composite chemical system provides superior protective properties compared to simple lamination, delivering abrasion resistance, heat resistance, and chemical resistance in an integrated coating layer.
2Reliability
If a covering clear plastic film is attached to the printed surface by lamination, then the printed image is protected from damage and distortion, but the cost increases
Solution Approach 1:
The protective function is merged with the coating application process itself. By applying the urethane coating composition directly to the printed substrate and curing it in-situ, the patent eliminates the need for separate lamination equipment and materials, reducing manufacturing cost while maintaining protection.
Solution Approach 2:
The patent changes the chemical parameters of the coating system by using a two-component urethane system with isocyanate index greater than 0.9. This parameter change enables the formation of a highly crosslinked, durable protective layer that provides superior protection at lower cost compared to lamination processes.
3Reliability
If conventional coating methods are used, then the printed surface is protected, but the abrasion resistance, high-temperature resistance, and chemical resistance are insufficient
Solution Approach 1:
The patent employs a composite chemical system where a polyisocyanate prepolymer reacts with a polyol to form a highly crosslinked urethane network. This composite material structure provides superior intermolecular bonding and network density, delivering enhanced abrasion resistance, high-temperature stability, and chemical inertness compared to conventional single-component coatings.
Solution Approach 2:
The patent optimizes the isocyanate index parameter to be greater than 0.9, which controls the crosslinking density of the cured urethane coating. This parameter change ensures sufficient unreacted isocyanate groups to maximize crosslinking, thereby enhancing the coating's resistance to abrasion, heat, and chemicals while maintaining film integrity.
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 coated printed substrate achieves good appearance, abrasion resistance, resistance to high temperatures, and resistance to chemicals without the need for additional laminates, enhancing durability and reducing manufacturing complexity.
Implementation Method 1
component A comprises a polyisocyanate prepolymer A1, wherein the polyisocyanate prepolymer A1 is a reaction product of a polyisocyanate monomer A1a and an isocyanate-polyreactive compound A1b... bringing together a component A and a component B to form a urethane coating composition... applying a layer of the urethane coating composition to the surface
Data Source
AI summary
A process for producing a coated, printed substrate comprising (a) providing a printed substrate, wherein the substrate comprises a surface on which resides one or more areas of a layer of an ink, (b) bringing together a component A and a component B to form a urethane coating composition, wherein component A comprises a polyisocyanate prepolymer A1, wherein the polyisocyanate prepolymer A1 is a reaction product of a polyisocyanate monomer A1a and an isocyanate-polyreactive compound A1b, wherein component B comprises one or more polyol B1, wherein the urethane coating composition has isocyanate index greater than 0.9, (c) applying a layer of the urethane coating composition to the surface. Also provided is a coated printed substrate made by such a method.