Polyol composition
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Solution Overview
Problem
Existing methods for producing synthetic leather using polycarbonate diol from 1,6-hexanediol and low-molecular carbonate result in high viscosity issues, leading to application challenges and non-uniform coating films, as well as concerns with chemical and abrasion resistance.
Innovation Solution
A polyol composition with a carbonate skeleton, ester, or ether skeleton, having specific viscosity and hydroxyl value ranges, and a glass transition temperature of -60°C or lower, is used to produce a urethane prepolymer that can be applied solventlessly, ensuring flexibility, chemical resistance, and moist heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polycarbonate diol obtained from 1,6-hexanediol and low-molecular carbonate is used as a base, then chemical resistance and oxidative degradation resistance are improved, but viscosity becomes high making application difficult and coating film surface smoothness deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the polyol by incorporating specific ratios of polycarbonate diol (30-70 mass%), polyester polyol (10-60 mass%), and polyether polyol (10-60 mass%). This parameter optimization reduces viscosity while maintaining chemical resistance, enabling proper application and coating film formation.
Solution Approach 2:
The invention creates a composite polyol system combining three different polyol types (polycarbonate diol, polyester polyol, polyether polyol) with specific molecular weight ranges. This composite approach balances the high chemical resistance of polycarbonate diol with the lower viscosity characteristics of polyester and polyether polyols, resolving the contradiction between reliability and ease of operation.
2Reliability
If high viscosity polyol composition is used, then chemical resistance is improved, but coating film thickness uniformity deteriorates
Solution Approach 1:
The patent optimizes viscosity parameters by controlling the molecular weights and ratios of constituent polyols. The resulting polyol composition has a viscosity of 50-500 cP at 25°C, which is low enough to ensure uniform coating film thickness while maintaining adequate chemical resistance through the presence of polycarbonate diol structures.
Solution Approach 2:
The composite polyol system combines polyols with different viscosity characteristics. Polyester polyol (number-average molecular weight 500-2000) and polyether polyol (number-average molecular weight 1000-3000) contribute to lower overall viscosity, enabling uniform coating application, while polycarbonate diol provides the chemical resistance foundation.
3Reliability
If solventless approach is used, then environmental compliance is improved, but flexibility and processability of the composition deteriorate due to high viscosity
Solution Approach 1:
The patent achieves environmental compliance through a solventless formulation while maintaining processability by carefully controlling the viscosity parameter of the polyol composition. The viscosity is reduced to 50-500 cP at 25°C through optimized polyol blending, allowing the solventless composition to be properly applied and processed without compromising environmental standards.
Solution Approach 2:
The solventless composite polyol system combines three types of polyols with complementary properties. This composition achieves both environmental compliance (no organic solvents) and adequate processability (viscosity 50-500 cP) by leveraging the synergistic effects of different polyol molecules with varying chain structures and intermolecular forces.
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 polyol composition enables the production of synthetic leather with improved flexibility, chemical resistance, and uniform thickness without solvents, addressing the viscosity and resistance issues of previous methods.
Implementation Method 1
A urethane prepolymer for synthetic leather production without a solvent, the urethane prepolymer being obtainable using the polyol composition according to any of [1] to 4] and a polyisocyanate
Implementation Method 2
comprising the step of applying a urethane prepolymer composition comprising the urethane prepolymer according to 5] onto a base fabric or a release support without a solvent, followed by moisture curing
Data Source
AI summary
An object of the present invention is to provide, for example, a polyol composition that can be used as a starting material in producing synthetic leather without a solvent, and a method for producing synthetic leather without a solvent. Another object of the present invention is to provide, for example, a polyol composition that produces a polyurethane film excellent in flexibility, chemical resistance, and moist heat resistance and serves as a starting material in producing synthetic leather without a solvent. The present invention provides a polyol composition for a starting material for synthetic leather production without a solvent, the polyol composition having a carbonate skeleton, having a viscosity of 100 to 1250 mPa·s measured at 50°C by a method of JIS K 1557-5 (2007), and having a hydroxyl value of 40 to 75 mgKOH/g measured by a method of JIS K 1557-1 (2007).