Waterborne Polyurethane Acrylate Topcoat for Ink Anchorage
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Solution Overview
Problem
Existing printable topcoatings for polyolefin materials face issues such as moderate anchorage, blocking, and poor chemical resistance, leading to undesirable pinholing and ink-anchorage characteristics, especially when applied over polypropylene, PET, or PE films.
Innovation Solution
Aqueous dispersion topcoatings comprising a waterborne aliphatic polyether polyurethane and a waterborne aliphatic urethane acrylate, with specific polyisocyanates and polyether polyols, providing improved anchorage, reduced pinholing, and enhanced chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyacrylate and polyurethane combinations are used for printable topcoats, then print receptivity is achieved, but anchorage to the face material becomes moderate and blocking occurs
Solution Approach 1:
The patent employs a composite topcoat formulation combining polyacrylate, polyurethane, and polyester polymers in specific ratios. This multi-component composite system synergistically provides both print receptivity (from polyacrylate) and improved anchorage with reduced blocking (from polyurethane-polyester combination), resolving the contradiction between printability and reliability.
Solution Approach 2:
The patent optimizes the compositional parameters of the topcoat by adjusting the weight percentages of different polymer components. Specifically, it modifies the ratio of polyacrylate to polyurethane-polyester and controls molecular weight parameters to achieve the optimal balance between print receptivity and anchorage properties, eliminating blocking issues.
2Ease of operation
If acrylic resin combinations are used for topcoats, then print receptivity is achieved, but anchorage and chemical resistance become poor
Solution Approach 1:
The patent creates a composite system where polyester-modified polyurethane is combined with polyacrylate. The polyurethane-polyester component specifically addresses the deficiency in anchorage and chemical resistance of pure acrylic resins, while maintaining print receptivity through the polyacrylate phase.
Solution Approach 2:
The patent introduces functional differentiation within the topcoat layers by having the polyurethane-polyester component concentrate at the interface with the face material to provide anchorage and chemical resistance, while the polyacrylate component remains dominant at the surface to ensure print receptivity. This local functional distribution resolves the contradiction.
3Ease of manufacture
If conventional topcoat formulations are used, then application is simplified, but pinholing and poor ink-anchorage characteristics occur
Solution Approach 1:
The patent modifies the molecular weight parameters and compositional ratios of the polymer components to eliminate pinholing while maintaining application simplicity. By optimizing the viscosity and crosslinking density through parameter adjustment, the formulation achieves both ease of manufacture and improved reliability in preventing pinholing and ensuring ink anchorage.
Data Source
AI summary
A topcoating (14) is disclosed for a face material (12) which exhibits desirable ink anchorage, anti-pinholing properties, moisture/water resistance, optical characteristics and/or anti-blocking properties. In one embodiment, the topcoating comprises a formulation of polyurethane and polyurethane acrylate. Suitably, the polyurethane is an aliphatic polyurethane and/or the polyurethane acrylate is an aliphatic polyurethane acrylate. In one suitable embodiment, either or both the polyurethane and polyurethane acrylate are water dispersible. In a further embodiment, suitably, the polyurethane is a polyether urethane. Suitably, the formulation may further include a crosslinker, e.g., a water soluble or water dispersible crosslinker.