Two-Component Polyurethane Composition for High DOI and Low VOC
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Solution Overview
Problem
Conventional water-borne two-component polyurethane compositions fail to achieve high distinctness of image (DOI) and gloss comparable to solvent-borne compositions while maintaining blister resistance and hardness, and they also have high volatile organic compound (VOC) content.
Innovation Solution
A two-component polyurethane composition is formulated by combining an emulsion polymer with a specific alcohol alkoxylate and a polyisocyanate, where the emulsion polymer contains greater than 15% hydroxy-functional alkyl (meth)acrylate units and the alcohol alkoxylate has a molecular weight of 1,000 g/mol or less, with specific ethylene oxide units, to enhance DOI and gloss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If water-borne two-component polyurethane compositions are used to reduce VOC content, then VOC content is reduced, but distinctness of image (DOI) and gloss are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the emulsion polymer, specifically requiring greater than 15% structural units of hydroxy-functional alkyl (meth)acrylate. This parameter change in the polymer structure enables water-borne formulations to achieve high DOI (74 or higher) and gloss (60° gloss of 85 or higher) while maintaining low VOC content.
Solution Approach 2:
The patent creates a composite system by combining a specifically formulated emulsion polymer with a polyisocyanate crosslinking agent. This two-component composite approach, where the emulsion polymer contains optimized hydroxy-functional alkyl (meth)acrylate units, enables simultaneous achievement of environmental compliance (low VOC) and aesthetic performance (high DOI and gloss).
2Object-generated harmful factors
If water-borne two-component polyurethane compositions are used to reduce VOC content, then VOC content is reduced, but gloss is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the emulsion polymer to contain greater than 15% structural units of hydroxy-functional alkyl (meth)acrylate. This compositional parameter change enables the formulation to achieve high gloss (60° gloss of 85 or higher, 20° gloss of 75 or higher) while maintaining water-borne status and low VOC content.
Solution Approach 2:
The patent enhances the local quality of the coating surface by incorporating hydroxy-functional alkyl (meth)acrylate units that specifically improve surface properties. This localized functional enhancement at the coating surface level achieves high gloss and DOI without requiring solvent-based formulations.
3Object-generated harmful factors
If conventional emulsion polymers are used in water-borne two-component polyurethane compositions, then VOC content is reduced, but appearance quality (DOI and gloss) is compromised
Solution Approach 1:
The patent fundamentally changes the parameter of emulsion polymer composition by requiring greater than 15% structural units of hydroxy-functional alkyl (meth)acrylate. This parameter change transforms conventional emulsion polymers into high-performance materials that deliver reliable appearance quality (DOI of 74 or higher, gloss of 85 or higher at 60°) in water-borne formulations.
Solution Approach 2:
The patent effectively copies the performance characteristics of solvent-borne polyurethane coatings (high DOI and gloss) into a water-borne system by using a specifically designed emulsion polymer with optimized hydroxy-functional alkyl (meth)acrylate content, thereby achieving similar aesthetic quality without the harmful VOC content.
4Manufacturing precision
If high DOI and gloss are achieved in water-borne polyurethane compositions, then appearance quality is improved, but blister resistance and hardness may be compromised
Solution Approach 1:
The patent optimizes the hydroxy-functional alkyl (meth)acrylate content to greater than 15% in the emulsion polymer, which improves DOI and gloss. Simultaneously, the two-component formulation with polyisocyanate creates a crosslinked network that maintains blister resistance and hardness, resolving the potential trade-off between appearance and durability.
Solution Approach 2:
The patent uses a composite two-component system combining the emulsion polymer with polyisocyanate crosslinking agent. This composite approach allows the hydroxy-functional alkyl (meth)acrylate units to provide high DOI and gloss, while the crosslinked network structure maintains durability properties including blister resistance and hardness.
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 composition provides coatings with a DOI of 74 or higher, 60° gloss of 85 or higher, and 20° gloss of 75 or higher, along with hardness of H or harder, while maintaining blister resistance to UV light, and reduces VOC content.
Implementation Method 1
combining an emulsion polymer with a specific alcohol alkoxylate and a polyisocyanate, where the emulsion polymer contains greater than 15% hydroxy-functional alkyl (meth)acrylate units and the alcohol alkoxylate has a molecular weight of 1,000 g/mol or less, with specific ethylene oxide units, to enhance DOI and gloss
Implementation Method 2
two-component polyurethane composition comprising (A) an aqueous dispersion comprising an emulsion polymer and from 2% to 20% of an alcohol alkoxylate, by weight based on the weight of the emulsion polymer; (B) a polyisocyanate
Data Source
AI summary
A two-component polyurethane composition comprising (A) an aqueous dispersion comprising an emulsion polymer and from 2% to 20% of an alcohol alkoxylate of formula (I), by weight based on the weight of the emulsion polymer, and (B) a polyisocyanate; the two-component polyurethane composition can provide coatings with a high distinctness of image.