Isocyanate-Terminated Prepolymer from Triglycerides
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Solution Overview
Problem
Conventional alkyd resins produced from triglycerides are highly viscous and require solvents for application, limiting their use in coating applications, whereas a solvent-free, low-viscosity isocyanate-terminated prepolymer derived from biological materials would be more desirable.
Innovation Solution
An isocyanate-terminated prepolymer comprising 30-60 wt% polymerized residues of a specific polyol derived from triglycerides, 40-55 wt% diphenyl methane diisocyanate (MDI), and 0-20 wt% glycol, with a hydroxyl number and viscosity suitable for solvent-free composition, is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional alkyd resins are produced from triglycerides, then the resin can be manufactured using traditional methods, but the resin becomes highly viscous and requires solvents for application
Solution Approach 1:
The patent changes the chemical parameters of the resin by reacting triglycerides with maleic anhydride to introduce cyclic anhydride groups, then further reacting with polyols to create hydroxy-functional prepolymer resins. This chemical modification transforms the resin from high viscosity to low viscosity, enabling solvent-free application while maintaining ease of manufacture through controlled reaction parameters
Solution Approach 2:
The patent creates a composite resin system by combining triglyceride-derived polyester chains with maleic anhydride grafts and polyol segments. This composite structure integrates the benefits of natural oils (renewability, cost) with modified functionality (low viscosity, reactivity), producing a material that is both easy to manufacture and apply without solvents
2Strength
If the resin is produced with high molecular weight, then the mechanical properties are improved, but the viscosity increases and solvents are required
Solution Approach 1:
The patent performs preliminary polymerization to create prepolymer chains with controlled molecular weights and desired mechanical properties before final curing. By pre-forming these intermediate structures with appropriate functionality, the resin achieves both strength and low viscosity, eliminating the need for solvents while maintaining mechanical performance
Solution Approach 2:
The patent controls the average functionality and molecular weight parameters during synthesis to optimize the balance between mechanical strength and viscosity. By adjusting the ratio of triglyceride to polyol and controlling reaction conditions, the resin achieves sufficient crosslinking density for strength while maintaining low enough viscosity for solvent-free application
3Ease of operation
If solvents are used to reduce viscosity, then the resin becomes easier to apply, but environmental impact increases and application efficiency decreases
Solution Approach 1:
The patent converts the potential harm of high viscosity (which would require solvents) into a benefit by chemically modifying the resin structure through maleic anhydride grafting and polyol reaction. This transformation reduces viscosity inherently, allowing solvent-free formulation that improves environmental performance while maintaining applicability through controlled rheology and reactive dilution mechanisms
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 solution provides a solvent-free, low-viscosity isocyanate-terminated prepolymer suitable for coating applications, enhancing application efficiency and reducing environmental impact.
Implementation Method 1
an isocyanate-terminated prepolymer produced from the reaction of a polyol with diphenyl methane diisocyanate (MDI)
Data Source
AI summary
An isocyanate-terminated prepolymer having three components. The first component is 30-60 wt % polymerized residues of a first polyol containing a substituent of formula (I)attached via a carbon-carbon single bond to a saturated carbon atom in a fatty acid hydrocarbyl group; wherein R1 and R2 are esterified residues of aliphatic or cycloaliphatic diols; and wherein the first polyol contains: (i) from 0.33 to 0.4 units of formula (I) per fatty acid hydrocarbyl group, and (ii) from 0 to 12 wt % esterified residues of at least one C4-C12 anhydride, C4-C12 diacid or C4-C12 lactone, not including units of formula (I) attached to a fatty acid hydrocarbyl group; and wherein the first polyol has a hydroxyl number from 75 to 150 mg KOH/g. The second component is 40-55 wt % polymerized residues of diphenyl methane diisocyanate. The third component is 0-20 wt % polymerized residues of a glycol having Mn from 300 to 3500.