Thermoplastic polyurethane resin elastomers
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Solution Overview
Problem
Conventional thermoplastic polyurethane resin elastomers face challenges in concurrently achieving a small change in elastic modulus depending on temperature, constant tensile strength, and excellent durability such as weather resistance, chemical resistance, transparency, and texture, particularly when using biomass resources, and they often suffer from issues like yellowing and limited applicability due to insufficient mechanical properties.
Innovation Solution
A thermoplastic polyurethane resin elastomer is formulated using a specific copolymerized polycarbonate diol, a specific polyisocyanate, and a specific aliphatic alcohol in a specific ratio, with the isocyanate compound comprising predominantly aliphatic or alicyclic isocyanate groups, the aliphatic alcohol being predominantly a C12 or lower aliphatic diol, and the polyol comprising predominantly copolymerized polycarbonate diol with a specific equivalent ratio, to enhance mechanical properties and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic polyurethane resin elastomers are used, then they can be shaped without vulcanization and offer wide ranges of hardness and elasticity, but they exhibit large change in elastic modulus depending on temperature and insufficient tensile strength
Solution Approach 1:
The patent changes the chemical composition parameters of the polyol component by incorporating specific cyclic carbonate structural units ( formulas (B1) and (B2) ) into the polycarbonate diol structure. This compositional parameter change results in improved tensile strength and reduced temperature dependence of elastic modulus, resolving the contradiction between strength and compositional stability.
Solution Approach 2:
The patent creates a composite molecular structure by copolymerizing different cyclic carbonate units ( formulas (B1) and (B2) ) with specific ratios along with formula (A) units. This composite approach at the molecular level combines the advantages of different structural units to achieve both high tensile strength and temperature stability of elastic modulus.
2Reliability
If polycarbonate diol is used to improve hydrolysis resistance and heat resistance, then durability is enhanced, but the resin has high viscosity and is difficult to handle
Solution Approach 1:
The patent introduces local structural variations by incorporating specific cyclic carbonate units ( formulas (B1) and (B2) ) at controlled ratios (5-50 mol% and 5-40 mol% respectively) into the polycarbonate diol chain. This local structural modification maintains the bulk properties for durability while reducing overall viscosity and improving processability.
Solution Approach 2:
The patent changes the molecular structure parameters of the polycarbonate diol by incorporating cyclic carbonate units with different ring structures and sizes. This parameter change reduces the polymer chain rigidity and intermolecular forces, thereby lowering viscosity while preserving hydrolysis and heat resistance properties.
3Adaptability or versatility
If simple thermoplastic polyurethane resins are used, then they exhibit thermoplasticity, but they do not satisfy the characteristics of being self-reinforced, easy to color, and recyclable
Solution Approach 1:
The patent optimizes the equivalent ratio parameter of isocyanate groups to total hydroxyl groups within 0.95-1.05. This precise parameter control ensures complete reaction stoichiometry that enhances self-reinforcement through optimal crosslinking density while maintaining thermoplasticity and improving colorability through controlled molecular weight distribution.
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 elastomer exhibits a small change in elastic modulus, constant tensile strength, and excellent durability, including weather and chemical resistance, while maintaining high transparency and good texture, making it suitable for various applications without yellowing.
Implementation Method 1
A thermoplastic polyurethane resin elastomer obtained by reacting an isocyanate compound (I), an aliphatic alcohol (II) having a number average molecular weight determined from the hydroxyl value of less than 300 and having only a hydroxyl group as a functional group, and a polyol (III)
Implementation Method 2
Polycarbonate diols are excellent in hydrolysis resistance, heat resistance and weather resistance
Implementation Method 3
form a higher-order structure composed of hard segment domains that are crystal phases formed by intermolecular cohesive force mainly stemming from hydrogen bonds
Implementation Method 4
a matrix that is based on the soft segment domains and shows high mobility on account of weak intermolecular force (Van der Waals force)
Data Source
AI summary
A thermoplastic polyurethane resin elastomer is obtained by reacting an isocyanate compound (I), an aliphatic alcohol (II) having a number average molecular weight determined from the hydroxyl value of less than 300 and having only a hydroxyl group as a functional group, and a polyol (III) having a number average molecular weight determined from the hydroxyl value of not less than 300 and not more than 10,000. The isocyanate compound (I) includes not less than 90 mol % in total of an aliphatic isocyanate compound containing two isocyanate groups and/or an alicyclic isocyanate compound containing two isocyanate groups. The aliphatic alcohol (II) includes not less than 90 mol % of a C12 or lower aliphatic diol. The polyol (III) includes not less than 80 mol % of a copolymerized polycarbonate diol (IIIA) including a linear repeating structural unit represented by formula (A) and a repeating structural unit represented by formula (B).