Aliphatic Polyurethane Film Modulus and Haze
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Solution Overview
Problem
Aliphatic thermoplastic polyurethane films lack mechanical durability, making them unsuitable for processing and handling conditions during manufacturing, and aromatic alternatives have poor UV resistance and high color, limiting their application.
Innovation Solution
An aliphatic thermoplastic polyurethane resin composition comprising an isocyanate compound, an isocyanate reactive compound, a chain extender, and additives, which forms a film with a modulus of at least 800 MPa and a haze value of less than 2%, enhancing mechanical durability and optical clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aliphatic thermoplastic polyurethane films are used, then UV resistance and optical clarity are maintained, but mechanical durability is insufficient
Solution Approach 1:
The patent modifies the molecular weight parameters of the polyol component (using polyols with 1,000-10,000 g/mol) and adjusts the isocyanate-to-polyol ratio (NCO/OH ratio of 0.8-1.2) to optimize the balance between mechanical durability and UV resistance. These parameter changes enable the aliphatic polyurethane to achieve both improved strength and maintained UV stability.
Solution Approach 2:
The patent creates a composite polyurethane system by combining specific polyol types (polyester polyols, polycarbonate polyols, or polyether polyols) with diisocyanates and chain extenders. This composite approach integrates the UV resistance of aliphatic structures with the mechanical durability provided by the specific polyol-isocyanate combination, resolving the contradiction between these properties.
2Strength
If aromatic thermoplastic polyurethane films are used, then mechanical durability is improved, but UV resistance and optical clarity deteriorate
Solution Approach 1:
The patent changes the chemical structure parameter from aromatic to aliphatic in the polyol component, which fundamentally alters the UV resistance while maintaining mechanical properties through careful selection of polyol molecular weight (1,000-10,000 g/mol) and formulation ratios. This parameter change eliminates the UV degradation issue while preserving mechanical durability.
3Illumination intensity
If aliphatic thermoplastic polyurethane films are used, then optical clarity is maintained, but mechanical strength is insufficient
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyol (1,000-10,000 g/mol) and the NCO/OH ratio (0.8-1.2) to achieve the right balance between chain flexibility (for optical clarity) and crosslinking density (for mechanical strength). These parameter adjustments allow the film to remain optically clear while gaining adequate mechanical strength.
Data Source
AI summary
An aliphatic thermoplastic polyurethane resin composition comprising: (a) an isocyanate compound; (b) an isocyanate reactive compound; (c) a chain extender compound; and (d) one or more additives; and wherein after the thermoplastic polyurethane resin composition is formed into an aliphatic thermoplastic polyurethane film having a thickness of 0.1 mm, the aliphatic thermoplastic polyurethane film has: (x) a modulus of at least 800 MPa at 25° C. and (y) a haze value of less than 2%.