Polycarbonate Diol Coating Composition for Scratch and Heat Resistance
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Solution Overview
Problem
Polycarbonate diol-based coating compositions used in solvent systems face limitations in achieving optimal low-temperature transparency, abrasion resistance, and heat resistance, particularly in applications requiring high scratch resistance and durability.
Innovation Solution
A coating composition comprising a polycarbonate diol with specific molecular weight and structural components, combined with an isocyanate compound and an organic solvent having a specific solubility parameter, to form a film with enhanced scratch recovery and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a polycarbonate diol is used in a solvent system, then the coating composition can be applied, but the selection of organic solvent is limited and performance is insufficient
Solution Approach 1:
The patent modifies the molecular weight parameter of the polycarbonate diol to fall within 500-10,000 and adjusts the structural composition (formula I content at 10-90 mass%) to achieve optimal balance between low-temperature transparency and solvent compatibility, thereby expanding solvent selection while maintaining coating performance
Solution Approach 2:
The patent creates a composite polyol system by combining polycarbonate diol with specific structural features (formula I and formula II) and optional polyester polyol components, forming a multi-component composition that achieves both versatility in solvent selection and reliability in coating performance
2Strength
If conventional polyurethane resins are used, then basic coating functions are achieved, but scratch resistance and heat resistance are insufficient
Solution Approach 1:
The patent optimizes the number-average molecular weight of polycarbonate diol (500-10,000) and the ratio of structural components (formula I at 10-90 mass%) to enhance molecular chain flexibility and intermolecular forces, achieving improved scratch resistance while maintaining heat resistance
Solution Approach 2:
The patent introduces specific local structural features (formula I with R11 groups and formula II carbonate structures) within the polycarbonate diol molecules to create regions with enhanced mechanical properties and thermal stability, thereby achieving both scratch and heat resistance
3Illumination intensity
If the structure represented by formula (I) is increased to improve low-temperature transparency, then abrasion resistance may be compromised
Solution Approach 1:
The patent establishes an optimal range for formula (I) structural content (10-90 mass%) and molecular weight (500-10,000) to balance the competing requirements of low-temperature transparency and abrasion resistance, preventing either property from being compromised
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 composition achieves excellent low-temperature transparency, abrasion resistance, and scratch recovery properties while maintaining heat resistance, addressing the limitations of existing polycarbonate diol-based coatings.
Implementation Method 1
polycarbonate diols can also be further compounded in a paint or a coating agent in which a crosslinking agent having reactivity with a hydroxyl group of melamine resins, isocyanate compounds
Implementation Method 2
The coating composition may contain an organic solvent having a vapor pressure of 1.0 kPa or more at 20 °C
Data Source
AI summary
The present invention provides a coating composition containing a component (1-A1), an isocyanate compound and an organic solvent, wherein the component (1-A1) is a polycarbonate diol composition including a structure represented by formula (I) (in the formula, R11 is a divalent aliphatic hydrocarbon group or the like, n11 is a number of 3 to 70) and a polycarbonate structure represented by formula (II) (in the formula, R21 is a divalent aliphatic hydrocarbon group or the like, and n21 is a number of 1 to 50), and having hydroxyl groups at both terminals, and having a number-average molecular weight of 300 or more and 10,000 or less, wherein with respect to a total mass of the structure represented by the formula (I) and the polycarbonate structure, the structure represented by formula (I) is contained in an amount of 5% by mass or more and 50% by mass or less, and the polycarbonate structure is contained in an amount of 50% by mass or more and 95% by mass or less.