Aqueous Binder Compositions with Grafted Polyurethane Resins
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Solution Overview
Problem
Existing aqueous binder compositions for coating applications lack a desirable combination of properties such as gloss, lightfastness, corrosion protection, scratch resistance, and mechanical resistance, and do not effectively incorporate alkyd resin moieties with polyurethane and acrylic resins.
Innovation Solution
Aqueous dispersions of polyurethane resins, alkyd resins, and acrylic resins are combined, with polyurethane resins containing moieties derived from grafted fatty acids, to create binders with improved application properties, including good wood penetration, fast drying, and reduced dirt pick-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aqueous dispersions of polyurethane resins and acrylic resins are combined, then adhesion and mechanical resistance are improved, but water resistance is impaired when acrylic resin mass fraction exceeds 12%
Solution Approach 1:
The patent changes the chemical parameter of the polyurethane resin by incorporating oil-derived moieties (fatty acids, alkyd resins) to modify the resin's properties. This allows the polyurethane to achieve both good adhesion (from acrylic) and water resistance (from oil-derived components) simultaneously, resolving the contradiction between mechanical resistance and water resistance when combining acrylic and polyurethane resins.
Solution Approach 2:
The patent creates a composite binder system combining acrylic resin, polyurethane resin with oil-derived moieties, and alkyd resin in specific mass ratios. This composite approach allows synergistic effects where each component contributes its strengths: acrylic provides adhesion, polyurethane provides mechanical resistance, and oil-derived components provide water resistance and gloss, overcoming the limitations of individual resin systems.
2Strength
If mass fraction of acrylic resin is increased to improve adhesion, then adhesion is improved, but water resistance is impaired
Solution Approach 1:
The patent modifies the polyurethane resin composition by incorporating oil-derived moieties to change its chemical parameters, enabling it to provide both adhesion (replacing part of acrylic function) and water resistance. This allows reducing acrylic content while maintaining adhesion through the modified polyurethane, thereby preserving water resistance.
Solution Approach 2:
The polyurethane resin with oil-derived moieties performs multiple functions: it provides mechanical resistance (primary polyurethane function), water resistance (from oil-derived components), and adhesion (through modified chemical structure). This multi-functionality reduces dependence on acrylic resin for adhesion, allowing lower acrylic content while maintaining both adhesion and water resistance.
3Ease of manufacture
If conventional aqueous binder compositions are used, then ease of manufacture is maintained, but desirable combination of properties (gloss, lightfastness, corrosion protection, scratch resistance) cannot be achieved
Solution Approach 1:
The patent employs a composite binder system combining three resin types in specific ratios, where each component contributes specific properties: acrylic for adhesion and lightfastness, polyurethane for mechanical resistance and scratch resistance, and oil-derived components for gloss and corrosion protection. This composite approach achieves the desirable combination of properties while maintaining aqueous formulation for ease of manufacture.
Solution Approach 2:
The patent optimizes the mass ratios of binder components (acrylic resin 20-70%, polyurethane resin 10-50%, alkyd resin 10-40%) to achieve the desired balance of properties. By carefully adjusting these parameters, the composition achieves simultaneous improvement in gloss, lightfastness, corrosion protection, and scratch resistance without compromising manufacturability.
Data Source
AI summary
The invention relates to mixtures of at least one acrylic resin dispersion A and a second dispersion B which is at least one of a polyurethane dispersion B1 which comprises, in its polymer, moieties derived from grafted fatty acids, and a mixture B2 of a polyurethane dispersion B21 and an aqueously dispersed alkyd resin B22, and to a method of use thereof for coating of porous substrates.