Acylurea Polymer Crosslinking Density and Chemical Resistance
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Solution Overview
Problem
Prior polyurethane systems based on cyclic carbonates and polyisocyanates suffer from limited crosslinking density, high viscosity, and poor curing behavior due to the presence of amine-labile ester groups, resulting in soft and elastic materials with low mechanical and chemical properties.
Innovation Solution
A curable organic polymer comprising acylurea units formed through an addition reaction between a carbodiimide and 2-oxo-1,3-dioxolane-4-carboxylic acid, which can be easily converted into a highly reactive and water-soluble binder suitable for high crosslinking density, allowing for the formation of hydroxypolyurethanes with good chemical and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyisocyanates are used to prepare polyurethane systems, then high resistance to acids, alkalis and chemicals is achieved, but monomeric low molecular weight polyisocyanate compounds become toxicologically unacceptable and volatile
Solution Approach 1:
The patent extracts and eliminates the harmful polyisocyanate components from the system while retaining the desired polyurethane properties. This is achieved by using alternative chemistry (cyclic carbonate + amine) that does not require toxic polyisocyanates, thereby removing the source of toxicity and volatility while maintaining chemical resistance through the resulting crosslinked network
Solution Approach 2:
The patent introduces cyclic carbonate compounds as an intermediary substance that enables polyurethane formation without direct use of polyisocyanates. The cyclic carbonate acts as a safe intermediate that reacts with amine hardeners to form the desired polyurethane crosslinked structure, mediating between safety requirements and performance requirements
2Manufacturing precision
If commercial polyisocyanates with functionality higher than 3 are used, then crosslinking density increases, but viscosity becomes very high and workability decreases
Solution Approach 1:
The patent segments the crosslinking function into two separate components: cyclic carbonate compounds provide the crosslinkable groups while amine hardeners provide the crosslinking chemistry. This segmentation allows each component to have optimized properties - the cyclic carbonate can maintain low viscosity while the amine hardener delivers high functionality and crosslinking density, resolving the viscosity-workability contradiction
Solution Approach 2:
The patent creates a composite system combining cyclic carbonate compounds and amine hardeners, where each component contributes specific properties. The cyclic carbonate provides low viscosity and solubility, while the amine hardener provides high functionality and crosslinking capability, achieving both good workability and high crosslinking density through material composition
3Manufacturing precision
If 2-hydroxyethyl 2-oxo-1,3-dioxolane-4-carboxylates are used, then cyclic carbonate groups are introduced, but ester groups are cleaved by amine hardener resulting in poor curing behavior
Solution Approach 1:
The patent extracts and removes the problematic ester linkage from the molecular structure, replacing it with a stable amide bond in the acylurea unit. This elimination of the cleavable ester group prevents degradation by amine hardeners while retaining the cyclic carbonate functionality, thereby resolving the curing behavior issue
Solution Approach 2:
The patent replaces the labile ester group (which is susceptible to cleavage) with a robust amide bond in the acylurea structure. The amide bond acts as a stable, non-cleavable linkage that maintains structural integrity during curing, effectively substituting a weak link with a strong one
4Strength
If binders with 2 to 3 cyclocarbonate groups are used, then crosslinking is achieved, but crosslinking density remains low resulting in soft and elastic materials
Solution Approach 1:
The patent changes the key parameter of crosslinking density by introducing acylurea units with multiple cyclic carbonate groups (n=2-10) that can react with multifunctional amine hardeners. This parameter change enables achievement of high crosslinking density (5-50 mol%), transforming the material from soft and elastic to hard and mechanically robust
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 polymer achieves high crosslinking density and stable, hard materials with improved mechanical and chemical properties, avoiding the limitations of prior systems, including low viscosity and VOC-free dosage forms, and preventing bubble formation during curing.
Implementation Method 1
A curable organic polymer comprising at least one acylurea unit formed through an addition reaction between a carbodiimide and 2-oxo-1,3-dioxolane-4-carboxylic acid
Implementation Method 2
These 2-oxo-1,3-dioxolane-4-carboxamides can also be cured with amine hardeners to form hydroxyurethanes
Data Source
AI summary
The present invention suggests a curable organic polymer comprising at least one acylurea unit represented by structural formula (I). Moreover, the present invention suggests a process for the preparation of said polymer and the use of said curable organic polymer for the preparation of a cured composition and for the preparation of hydroxyurethanes.