Decorative Sheet with Blocked Isocyanate for Chemical Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing decorative sheets for resin molded articles lack sufficient moldability and chemical resistance, particularly when exposed to skin care products like sunscreen and insect repellents, necessitating the development of a new technique that balances these properties.
Innovation Solution
A decorative sheet comprising a base material layer and a surface protective layer formed from an ionizing radiation curable resin composition containing blocked isocyanates, which provides excellent moldability and chemical resistance by controlling crosslinking density during the molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a decorative sheet uses a conventional surface protective layer without blocked isocyanate, then the manufacturing process is simple, but the chemical resistance against skin care products is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the surface protective layer by incorporating blocked isocyanate alongside ionizing radiation curable resin. This parameter modification enables the layer to achieve high chemical resistance against skin care products while maintaining compatibility with ionizing radiation curing processes, thus resolving the contradiction between reliability improvement and composition complexity.
Solution Approach 2:
The surface protective layer is designed as a composite material system combining ionizing radiation curable resin with blocked isocyanate. This composite structure leverages the crosslinking capability of blocked isocyanate to enhance chemical resistance, while the ionizing radiation curable resin provides moldability and adhesion, together achieving both improved reliability and controlled complexity.
2Reliability
If the surface protective layer contains blocked isocyanate for chemical resistance, then chemical resistance improves, but the moldability during injection molding may deteriorate
Solution Approach 1:
The blocked isocyanate is pre-incorporated into the surface protective layer in a dormant state before injection molding. The blocking mechanism prevents premature crosslinking reactions during the molding process, allowing the decorative sheet to maintain good moldability. The crosslinking activation occurs only after molding when exposed to high temperature and pressure, thus resolving the contradiction between preliminary chemical resistance preparation and manufacturing ease.
Solution Approach 2:
The surface protective layer exhibits dynamic behavior where the blocked isocyanate remains inactive during molding (maintaining flexibility and moldability) and activates under high temperature and pressure conditions (achieving crosslinking and chemical resistance). This dynamic characteristic allows the material to adapt its properties according to the processing stage, resolving the contradiction between moldability and chemical resistance.
3Reliability
If the surface protective layer is highly crosslinked for chemical resistance, then chemical resistance improves, but the adhesion to resin molded article deteriorates
Solution Approach 1:
The surface protective layer is designed to undergo crosslinking activation only after the injection molding process is complete. During molding, the blocked isocyanate remains dormant, allowing the layer to maintain flexibility and strong adhesion to the resin molded article. After molding, exposure to high temperature and pressure activates the crosslinking, achieving chemical resistance without compromising adhesion strength.
Solution Approach 2:
The surface protective layer exhibits dynamic crosslinking behavior that adapts to different processing stages. During injection molding, the material remains uncrosslinked for optimal adhesion, and crosslinking is activated only after bonding is established, ensuring both strong adhesion and subsequent chemical resistance.
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 decorative sheet achieves high moldability and chemical resistance, preventing contamination from skin care products and maintaining flexibility during molding, while ensuring excellent chemical resistance and heat-resistant adhesion in the final resin molded article.
Implementation Method 1
a surface protective layer formed of an ionizing radiation curable resin composition
Implementation Method 2
the surface protective layer containing a blocked isocyanate
Data Source
Figure 1~2
AI summary
The present invention provides a decorative sheet that excels in moldability and a decorative resin-molded article that uses the decorative sheet and that excels in chemical resistance. In the decorative sheet, at least a substrate layer and a surface protection layer formed of an ionizing radiation curable resin composition are stacked. The surface protection layer includes blocked isocyanate.