Carboxyl-Functional Polyether Basecoat for Stone Chip Resistance
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Solution Overview
Problem
Current multi-layer paint systems face challenges in mechanical resistance, particularly against stone chips, and there is a need for environmentally friendly alternatives to solvent-based coatings.
Innovation Solution
A pigmented aqueous basecoat containing a carboxyl-functional polyether-based reaction product, produced by reacting cyclic tetracarboxylic acid dianhydrides with polyethers, is used to enhance stone chip resistance and facilitate the production of multi-coat paint systems in an environmentally friendly manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solvent-based coatings are replaced by aqueous coating agents, then environmental compatibility is improved, but mechanical resistance against stone chips deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous basecoat by incorporating specific reaction products with carboxyl groups and epoxy groups in controlled ratios. The basecoat contains 5-50 wt% of reaction products of epoxidized polyesters or polyethers with carboxylic acids, and 50-95 wt% of carboxyl-functional polyether-based reaction products. This parameter optimization enables aqueous coatings to achieve improved stone chip resistance while maintaining environmental compatibility.
Solution Approach 2:
The patent creates a composite aqueous coating system by combining multiple functional components: carboxyl-functional polyether-based reaction products, epoxidized polyester/polyether reaction products, and inorganic fillers (5-50 wt% silica, alumina, or aluminum hydroxide). This composite formulation synergistically improves mechanical resistance while maintaining the aqueous (environmentally friendly) nature of the coating.
2Strength
If conventional basecoat formulations are used, then production process is simple, but stone chip resistance is insufficient
Solution Approach 1:
The patent specifies precise compositional parameters for the basecoat: 5-50 wt% epoxidized polyester/polyether reaction products, 50-95 wt% carboxyl-functional polyether-based reaction products, and 5-50 wt% inorganic fillers. The carboxyl-functional polyether reaction products are produced by reacting polyether polyols with tetracarboxylic acid dianhydrides in controlled molar ratios (0.7/2.3 to 1.6/1.7) to achieve acid numbers of 5-80 mg KOH/g. These controlled parameter changes enable improved stone chip resistance while maintaining manufacturability.
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 basecoat material significantly improves stone chip resistance and allows for the production of multi-coat paint systems with enhanced mechanical stability while being environmentally friendly, suitable for use in the automotive industry.
Implementation Method 1
carboxyl-functional polyether-based reaction product, which is produced by reacting (a) at least one cyclic tetracarboxylic acid dianhydride with (b) at least one polyether
Implementation Method 2
the basecoat layer together is hardened with the clear coat layer
Implementation Method 3
a polymer film is formed from the paint applied in step (1)
Data Source
AI summary
The present invention relates to a pigmented aqueous base paint containing a polyether-based reaction product which can be produced by reacting (a) at least one cyclic tetracarboxylic acid dianhydride with an aliphatic, aromatic or araliphatic radical X which bridges both anhydride groups, with b) at least one polyether of general structural formula (II), in which R is a C3 to C6 alkylene radical and n is selected accordingly in such a way that the polyether (b) has a number-average molecular weight of 500 to 5000 g/mol, wherein components (a) and (b) are used in a molar ratio of 0.7/2.3 to 1.6/1.7 in the reaction and the resulting reaction product has an acid number of 5 to 80 mg KOH/g. The invention further relates to a reaction product of special dianhydrides and a polyether and to the use of base paints according to the invention or to base paints containing the reaction product according to the invention.