Polyester Polyol for Low-Solvent Automotive Coatings
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Solution Overview
Problem
Current coating compositions for automotive applications face challenges in achieving a balance of properties such as low solvent usage, high solids content, corrosion resistance, abrasion resistance, and meeting industry standards for hardness and flexibility, often requiring compromises that affect other desired properties.
Innovation Solution
A polyester polyol is developed through a reaction product involving a polyol with 3 or more hydroxyl groups, dicarboxylic acid or anhydride with 3 or fewer carbon atoms, monocarboxylic acid or anhydride, and optional diol or dicarboxylic acid or anhydride, with specific molar ratios and hydroxyl and acid values, to create a coating composition that is curable at low temperatures and provides improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high solids content coating is used to improve resin and pigment transfer efficiency, then application robustness increases, but achieving balanced physical properties such as hardness and flexibility becomes more difficult
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyester polyol, specifically controlling the hydroxyl value (60-300 mg KOH/g) and acid value (less than 15 mg KOH/g), and using specific molar ratios of polyol to dicarboxylic acid (1.08:1 to 1.75:1) and to monocarboxylic acid (1.25:1 to 4:1). These parameter changes enable the coating to achieve high solids content while maintaining balanced physical properties including hardness and flexibility.
2Object-affected harmful factors
If low amounts of organic solvent are used to meet environmental requirements, then environmental compliance improves, but achieving desired coating properties becomes more challenging
Solution Approach 1:
The patent changes the chemical parameters of the polyester polyol components, using specific ratios of polyols with 3 or more hydroxyl groups to dicarboxylic acids with 3 or fewer carbon atoms, and controlling the diol content to less than 10 weight %. These parameter modifications enable the formulation to achieve desired coating properties with reduced organic solvent content, meeting environmental compliance requirements.
3Productivity
If high solids content is used to improve resin transfer efficiency, then application robustness increases, but the complexity of achieving balanced properties such as corrosion resistance, abrasion resistance, and chemical resistance increases
Solution Approach 1:
The patent simplifies the formulation complexity by establishing specific parameter ranges: diol content of 0-10 weight %, dicarboxylic acid with greater than 3 carbons of 0-10 weight %, and controlled molar ratios of polyol to dicarboxylic acid (1.08:1 to 1.75:1) and to monocarboxylic acid (1.25:1 to 4:1). These defined parameters enable high solids content formulations to achieve balanced corrosion resistance, abrasion resistance, and chemical resistance without excessive formulation complexity.
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 resulting coating composition exhibits high hardness, good appearance, and robustness, with the ability to form a continuous film at low temperatures, enhancing the balance of properties and meeting automotive industry standards while minimizing solvent usage.
Implementation Method 1
a polyester polyol including a reaction product obtained from components including: (i) a polyol including 3 or more hydroxyl groups; (ii) a dicarboxylic acid or an anhydride thereof; (iii) a monocarboxylic acid or an anhydride thereof
Data Source
AI summary
A polyester polyol includes a reaction product obtained from: (i) a polyol including 3 or more hydroxyl groups; (ii) a dicarboxylic acid or an anhydride thereof that includes 3 carbon atoms or fewer between the carboxylic acid groups or the anhydride thereof; (iii) a monocarboxylic acid or an anhydride thereof; (iv) optionally a diol; and (v) optionally a dicarboxylic acid or an anhydride thereof that includes greater than 3 carbons between the carboxylic acid groups or the anhydride thereof. A molar ratio of (i)+(iv) to (ii)+(v) ranges from 1.08:1 to 1.75:1, and a molar ratio of (i)+(iv) to (iii) ranges from 1.25:1 to 4:1. The reaction product has a hydroxyl value of from 60 to 300 mg KOH/g, and an acid value of less than 15 mg KOH/g.