Polycarbonate diol-containing composition, process for producing the same, polyurethane obtained using the same, and process for producing the polyurethane
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Solution Overview
Problem
Conventional polycarbonate diols synthesized from 1,6-hexanediol are crystalline, leading to poor handleability and polyurethanes with limited flexibility, elongation, and bendability, especially at low temperatures, and result in artificial leathers with a hard texture and poor 'feeling'.
Innovation Solution
A polycarbonate diol composition is developed by polymerizing a diaryl carbonate, 2,2-dialkyl-1,3-propanediol, and another diol, with specific repeating units and proportions, to create a liquid diol that enhances flexibility and moldability while maintaining heat resistance and weatherability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polycarbonate diols synthesized from 1,6-hexanediol are used, then heat resistance and hydrolytic resistance are improved, but the diols are crystalline and have poor handleability at ordinary temperature
Solution Approach 1:
The invention changes the chemical structure parameters of the polycarbonate diol by introducing specific repeating units (formulae A and B) with branched alkyl groups at the 2-position of the propanediol backbone. This structural modification disrupts crystallinity while maintaining the polycarbonate backbone's inherent heat and hydrolytic resistance, transforming the material from a crystalline wax to a liquid at ordinary temperature.
Solution Approach 2:
The invention creates a composite molecular structure within the polycarbonate diol by combining different repeating units (formulae A and B) in specific proportions. Formula A provides the polycarbonate backbone with heat resistance, while formula B introduces branching that prevents crystallization. The synergistic combination achieves both thermal stability and liquid state at room temperature.
2Reliability
If polycarbonate diols synthesized from 1,6-hexanediol are used, then durability is improved, but the polyurethanes show susceptibility to soft-segment agglomeration and have poor flexibility and elongation
Solution Approach 1:
The invention modifies the molecular parameters of the soft segment by incorporating repeating units with 2-position substituted propanediol structures. This changes the packing and intermolecular interactions of the soft segments, preventing agglomeration while maintaining the durability benefits of the polycarbonate backbone. The result is improved flexibility and elongation without sacrificing durability.
3Temperature
If polycarbonate diols synthesized from 1,6-hexanediol are used, then heat resistance is improved, but the polyurethane solutions have high viscosity and poor handleability
Solution Approach 1:
The invention changes the molecular architecture parameters by introducing branching structures at the 2-position of the propanediol units. This branching disrupts chain packing and reduces intermolecular forces, thereby lowering the viscosity of polyurethane solutions while preserving the heat resistance conferred by the polycarbonate backbone. The liquid state of the diol itself also contributes to lower solution viscosity.
4Reliability
If polycarbonate diols synthesized from 1,6-hexanediol are used, then durability is improved, but the artificial leathers have hard texture and poor feeling
Solution Approach 1:
The invention modifies the microstructural parameters of the artificial leather by using polycarbonate diols with 2-position substituted propanediol units. This structural change prevents crystallization and promotes a more amorphous, flexible matrix structure in the final product. The resulting artificial leather maintains the durability of polycarbonate-based materials while achieving a softer, more supple texture that better mimics natural leather.
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 new polycarbonate diol composition results in polyurethanes that are flexible, have excellent low-temperature properties, and improved handleability, producing artificial leathers with high heat resistance and a soft-touch feel.
Implementation Method 1
polymerizing a diaryl carbonate (i), 2,2-dialkyl-1,3-propanediol (ii), and a diol (iii) other than a 2,2-dialkyl-1,3-propanediol
Data Source
AI summary
A polycarbonate diol-containing composition obtainable by polymerizing a diaryl carbonate (i), a 2,2-dialkyl-1,3-propanediol (ii), and a diol (iii) other than a 2,2-dialkyl-1,3-propanediol, in the presence of a metal compound catalyst, wherein a total content of residual monomers of the (ii) and (iii) above in the composition is 1% by weight or less.