Aqueous Polyurethane Coatings with Phosphoric Esters

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Solution Overview

Problem

Current aqueous coating compositions face limitations in achieving high pinhole and popping limits, especially at high layer thicknesses, while maintaining excellent adhesion, corrosion resistance, and visual appearance.

Innovation Solution

Development of new aqueous mixtures containing saturated or unsaturated polyurethane as a binder, combined with phosphoric acid esters and color/effect pigments, which are curable through physical, thermal, or dual-cure methods, including actinic radiation, to produce stable and defect-free thermosetting or thermoplastic materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional aqueous coating compositions are used, then adhesion and corrosion resistance are maintained, but pinhole and popping limits are low especially at high layer thicknesses

Engineering Contradiction:
Improvepinhole limitVSAvoidlayer thickness
Core Design Contradiction:
Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent modifies the chemical composition parameters of the aqueous coating by incorporating specific phosphoric acid esters (Formula I) with controlled molecular structures (varying R and R1 groups) and optimizing their concentration ranges (0.1-10% by weight). This parameter optimization enables the coating to maintain structural integrity and eliminate pinholes even at high layer thicknesses of 20-50 μm and above, resolving the contradiction between pinhole limit and applicable layer thickness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite aqueous coating system combining polyurethane binders (saturated, unsaturated, or grafted with olefinically unsaturated compounds) with phosphoric acid esters (Formula I) and color/effect pigments. This composite formulation synergistically enhances both adhesion properties and defect-free film formation, achieving pinhole-free coatings at high thicknesses while maintaining excellent adhesion and corrosion resistance

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conventional aqueous coating compositions are used, then basic coating properties are maintained, but visual appearance shows light-dark shades (clouds) and overall impression is reduced

Engineering Contradiction:
Improvevisual appearance qualityVSAvoidlight-dark shades (clouds)
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the molecular structure parameters of phosphoric acid esters (Formula I) by varying the alkyl/alkenyl groups (R and R1) and their chain lengths, along with controlling the ester concentration (0.1-10% by weight). This precise parameter control ensures uniform pigment dispersion and consistent curing behavior, eliminating light-dark shades and clouds while achieving excellent visual appearance and color uniformity across the coating surface

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If new phosphoric acid ester formulations are incorporated, then pinhole and popping limits increase, but production complexity may increase

Engineering Contradiction:
Improvepopping limitVSAvoidproduction complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent establishes specific parameter ranges for phosphoric acid esters (Formula I) including the structural parameters of R and R1 groups and the concentration range of 0.1-10% by weight. Within these defined parameters, the formulations achieve high popping limits (exceeding 40 μm in many cases) while maintaining straightforward production processes using conventional mixing and application equipment, thus resolving the contradiction between manufacturing precision and ease of manufacture

Inventive Principle:
Principle #35Parameter changes

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 new mixtures are reproducibly produced, storage-stable, and easily processed, achieving high pinhole and popping limits, excellent adhesion, and visual appearance, even at high layer thicknesses, with improved performance compared to existing coatings.

Implementation Method 1

The trioorganophosphates serve to adjust the water vapor permeability of the basecoats or solid-color topcoats produced from the known water-based basecoats or solid-color topcoats

Methodology Applied
Scientific EffectWater vapor permeability: Permeation

Implementation Method 2

The present invention relates to new aqueous mixtures which can be cured physically, thermally or both thermally and with actinic radiation

Methodology Applied
Scientific EffectThermal curing:

Implementation Method 3

The present invention relates to new aqueous mixtures which can be cured physically, thermally or both thermally and with actinic radiation

Methodology Applied
Scientific EffectActinic radiation curing: Photopolymerisation

Implementation Method 4

EP 0507633A2 describes a curable resin composition containing a compound containing at least one polymerizable acrylic radical, methacrylic radical, vinyl radical or combinations thereof

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP1940951B1Aqueous mixtures curable physically, thermally or thermally and with actinic radiation
Publication Date: 2013.12.11 BASF COATINGS GMBH

AI summary

Aqueous mixtures which are curable physically, thermally or thermally and with actinic radiation and comprise: A) at least one ionically and/or nonionically stabilized polyurethane which is saturated, unsaturated and/or grafted with olefinically unsaturated compounds as a binder, B) at least one colour and/or effect pigment and C) at least one phosphoric ester of the general formula: (R1ORO)3P=O in which the variables have the following definition: R is an alkanediyl group having 2 to 10 carbon atoms and R1 is an alkyl group having 2 to 10 carbon atoms; processes for their preparation and their use.