Structured Clearcoat Composition Without Fumed Silica
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Solution Overview
Problem
Existing coating compositions require significant amounts of fumed silica and structuring pastes to achieve stable, structured clear coats, which limits their application in high-quality paint finishes, particularly in automotive series and refinishes, and lacks stability against settling and chemical resistance.
Innovation Solution
A coating composition comprising a polyol component, a crosslinking agent with reactive hydroxyl groups, a polyamide component, and a polycarboxamide component, which forms stable structured clear coats without the need for fumed silica or structuring pastes, ensuring high ring line stability, scratch resistance, and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pyrogenic silica and structuring pastes are used to achieve stable structured clear coats, then coating stability and surface structuring are improved, but coating complexity and requirement for multiple additives increase
Solution Approach 1:
The patent removes pyrogenic silica and structuring pastes from the coating composition, retaining only the essential polyol and crosslinking agent components. This extraction eliminates the need for multiple additives while maintaining coating stability through the optimized polyol-crosstlinking agent system with specific functional groups.
Solution Approach 2:
The polyol and crosslinking agent components perform multiple functions simultaneously: they provide coating stability, form the structured surface, and enable self-crosslinking. The system is self-sufficient, requiring no external matting agents or structuring pastes, as the reactive groups in the polyol and crosslinking agent directly create the structured coating layers.
2Shape
If significant amounts of fumed silica are used to achieve structured surfaces, then surface structuring is improved, but scratch resistance and chemical resistance deteriorate
Solution Approach 1:
The patent changes the fundamental parameters of the coating system by using a polyol with specific functional groups (carboxylic acid, hydroxyl, amine) and a crosslinking agent with reactive groups, replacing the traditional silica-based approach. This parameter change enables the formation of structured surfaces through chemical crosslinking rather than physical silica particles, thereby improving scratch and chemical resistance.
Solution Approach 2:
The patent creates a composite coating system where the polyol and crosslinking agent form an integrated crosslinked network. This composite structure provides both surface structuring and enhanced mechanical/chemical properties, as the crosslinked polymer matrix inherently resists scratching and chemical attack better than silica-filled coatings.
3Shape
If structuring pastes are used to achieve structured clear coats, then surface structuring is improved, but ring line stability and whitening resistance deteriorate
Solution Approach 1:
The patent optimizes the chemical parameters of the polyol and crosslinking agent to achieve both surface structuring and ring line stability. The specific functional groups and molecular structures are selected to ensure proper crosslinking density and network formation, which prevents ring lines while maintaining surface structure. This eliminates the compromise between structuring and stability.
4Stability of the object's composition
If pyrogenic silica is used to achieve stable coating compositions, then coating stability is improved, but chemical resistance and scratch resistance deteriorate
Solution Approach 1:
The patent creates a crosslinked polymer composite where the polyol and crosslinking agent form an integrated network structure. This composite material provides inherent chemical resistance through the crosslinked matrix, eliminating the need for pyrogenic silica. The stability comes from the chemical crosslinks rather than physical filler particles, thereby simultaneously achieving both stability and chemical resistance.
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 achieves stable, high-quality structured clear coats with enhanced scratch resistance and chemical resistance, minimizing whitening after condensation water tests, and maintains stability against settling, making it suitable for automotive applications.
Implementation Method 1
at least one polyol component (A), at least one crosslinking agent component (B) with groups reactive towards hydroxyl groups of component (A)
Implementation Method 2
forms structured coating layers, in particular clearcoat layers
Data Source
AI summary
The invention relates to coating material compositions, comprising (i) at least one polyol component (A), (ii) at least one crosslinking agent component (B) having groups reactive to hydroxyl groups of component (A), (iii) at least one polyamide component (P1) in which the acid amide groups are linked by a saturated, aliphatic hydrocarbon radical having 6 to 10 carbon atoms and which is employed in particulate form, wherein the particle size distribution of the primary particles thereof has a median particle size (D50) of 20 to 100 μm and (iv) at least one polycarboxamide component (P2), characterized in that the polycarboxamide component (P2) has the following structural formula, (I), wherein s = 1, 2 or 3, t = 0 or 1, and s + t = 2 or 3, R represents a special (s+t)-valent organic radical and at least one of the radicals R1 and R2 bears at least one hydroxyl group. The invention also relates to the production of such coating material compositions, to the use thereof in the production of multilayer lacquers and to the use of a combination of (P1) and (P2) as an additive in coating material compositions for producing textured lacquer layers, in particular textured clearcoat layers.