Polycarbonate Diol Stabilization via Terminal OH Control
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Solution Overview
Problem
Current polycarbonate diols used in coating materials and polyurethanes face issues with roughness, tackiness, and unstable reactions due to high crystallinity and molecular weight distribution, leading to inadequate hydrolysis resistance, heat resistance, and physical properties like strength and impact resilience.
Innovation Solution
A polycarbonate diol with a specified primary terminal OH ratio, calculated through specific chromatography analysis, is developed to stabilize reactions and control molecular weight distribution, preventing gel formation and tackiness, while maintaining balanced performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polycarbonate diol using 1,6-hexanediol as a raw material is used, then hydrolysis resistance and heat resistance are improved, but crystallinity increases making it unsuitable for coating materials
Solution Approach 1:
The patent uses a composite approach by combining 1,6-hexanediol (providing hydrolysis and heat resistance) with 1,5-pentanediol (reducing crystallinity) to create a copolycarbonate diol with balanced properties suitable for coating materials
Solution Approach 2:
The patent changes the compositional parameters by controlling the ratio of different diol units in the copolycarbonate chain, specifically adjusting the 1,5-pentanediol content to optimize the balance between resistance properties and crystallinity
2Productivity
If the reaction rate is increased to achieve target molecular weight, then productivity is improved, but partial macromolecularization occurs producing fine gel that degrades product quality
Solution Approach 1:
The patent uses a specific isocyanate compound as an intermediary reacting agent that moderates the reaction process, allowing faster reaction rates while preventing unwanted macromolecularization and gel formation through controlled reactivity
Solution Approach 2:
The patent optimizes reaction parameters including temperature, catalyst amount, and isocyanate-to-hydroxyl ratio to achieve the desired balance between reaction speed and product quality, preventing fine gel formation while maintaining productivity
3Manufacturing precision
If the reaction rate is decreased to prevent macromolecularization, then product quality is improved, but molecular weight distribution broadens causing surface tackiness and decreased physical properties
Solution Approach 1:
The patent employs a specifically selected isocyanate compound that acts as a mediator to maintain narrow molecular weight distribution while preventing surface tackiness, allowing adequate reaction progress without broadening the molecular weight distribution
Solution Approach 2:
The patent carefully controls reaction parameters such as temperature profile, catalyst concentration, and stoichiometric ratios to maintain narrow molecular weight distribution and prevent surface tackiness while ensuring adequate crosslinking for physical properties
4Reliability
If conventional dehydration processes are used to stabilize reaction, then moisture content is reduced, but additional process steps are required and sufficient stabilization is not achieved
Solution Approach 1:
The patent extracts the moisture sensitivity issue from the process by selecting raw materials and reaction conditions that are inherently less sensitive to moisture, eliminating the need for complex dehydration processes while achieving sufficient reaction stabilization
Solution Approach 2:
The patent changes the reaction parameters including catalyst selection, temperature control, and atmosphere management to achieve stable reactions without requiring extensive dehydration processes, simplifying the overall manufacturing process
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 polycarbonate diol achieves a coating film with no roughness or tackiness, exhibiting excellent hydrolysis resistance, heat resistance, and physical properties such as strength and impact resilience, ensuring stable and flexible polyurethane and thermoplastic elastomer production.
Implementation Method 1
the polycarbonate diol is reacted with a compound having a functional group reactive with a hydroxyl group, such as an isocyanate
Implementation Method 2
terminal hydroxyl groups in a polycarbonate diol... calculated by a specific method using chromatography analysis
Data Source
AI summary
A polycarbonate diol comprising repeating units represented by the following formula (A) and a terminal hydroxy group. It is characterized in that 60-100 mol% of the repeating units represented by the formula (A) are repeating units represented by the following formula (B) or (C), the amount of the repeating units represented by the formula (B) is 10-50 mol%, excluding 50 mol%, based on the total amount of the repeating units represented by the formula (A), and the polycarbonate diol has a terminal primary OH ratio of 95-98.5%. (A) (In the formula, R represents a C2-12 divalent aliphatic or alicyclic hydrocarbon.)