Silane Copolymer Coating for Low VOC Multicoat Paints
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Solution Overview
Problem
Current solventborne pigmented coating compositions for multicoat paint systems rely heavily on melamine resins, which pose environmental concerns due to formaldehyde emissions, and struggle to achieve balanced performance properties like intercoat adhesion, stonechip resistance, and hardness while minimizing VOC content.
Innovation Solution
A solventborne pigmented coating composition with a solids fraction of at least 35% containing a copolymer derived from olefinically unsaturated monomers, specifically formulated to replace melamine resins, ensuring effective intercoat adhesion, stonechip resistance, and high hardness without adverse effects on other properties, and featuring a low VOC content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If melamine resins are used as crosslinkers to achieve good performance properties, then intercoat adhesion and stonechip resistance are improved, but formaldehyde emissions increase causing environmental burden
Solution Approach 1:
The patent extracts and removes the harmful melamine resin crosslinker from the coating composition, replacing it with a polymer containing silane groups that provides equivalent performance without formaldehyde emissions. This directly addresses the contradiction by eliminating the source of formaldehyde while maintaining adhesion properties.
Solution Approach 2:
The patent changes the chemical composition parameter by using a polymer with silane groups instead of melamine resins. This substitution maintains the crosslinking functionality and adhesion performance while eliminating formaldehyde emissions, thus resolving the environmental burden issue.
2Strength
If melamine resins are used as crosslinkers to achieve good performance properties, then stonechip resistance is improved, but formaldehyde emissions increase causing environmental burden
Solution Approach 1:
The patent removes the harmful melamine resin crosslinker and replaces it with a silane-containing polymer that provides equivalent stonechip resistance without formaldehyde emissions, directly resolving the contradiction between performance and environmental burden.
Solution Approach 2:
The patent changes the crosslinking mechanism from melamine-based to silane-based, maintaining stonechip resistance while eliminating formaldehyde emissions. This parameter substitution resolves the contradiction by achieving the same mechanical performance through a different chemical pathway.
3Object-generated harmful factors
If the solids fraction is increased to reduce VOC content, then environmental profile is improved, but achieving balanced performance properties becomes more challenging
Solution Approach 1:
The patent changes the chemical composition by incorporating silane-containing polymers that enable effective crosslinking at higher solids fractions. This allows the formulation to achieve 35% or higher solids content while maintaining adhesion, stonechip resistance, and hardness through the silane crosslinking mechanism.
Solution Approach 2:
The patent uses a composite approach by combining silane-containing polymer units with other polymer components to create a formulation that achieves balanced performance properties at high solids fraction. The silane groups provide crosslinking functionality that compensates for the reduced solvent content, maintaining film integrity and performance.
4Object-generated harmful factors
If high solids fraction is used to reduce VOC content, then environmental profile is improved, but intercoat adhesion becomes harder to achieve
Solution Approach 1:
The patent changes the crosslinking chemistry to silane-based systems that function effectively at high solids fractions. The silane groups undergo hydrolysis and condensation to form crosslinked networks that ensure strong intercoat adhesion even when VOC content is reduced and solids fraction is increased to 35% or higher.
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 outstanding performance properties, including improved intercoat adhesion and stonechip resistance, while significantly reducing formaldehyde emissions and VOC content, thus enhancing both environmental and economic aspects of paint system production.
Implementation Method 1
The copolymer (A) contains silane groups which can crosslink by hydrolysis and condensation
Implementation Method 2
The copolymer (A) contains silane groups which can crosslink by hydrolysis and condensation
Data Source
AI summary
The present invention relates to a solventborne, pigmented coating composition having a solids fraction of at least 35%, which comprises, based on the total amount of the coating composition, 0.1 to 1.5 wt % of at least one copolymer (A), where the copolymer (A) is obtainable by copolymerization of a mixture of olefinically unsaturated monomers (a) in at least one organic solvent, the mixture of monomers (a) to be polymerized consists of(a1) 10 to 60 mol % of at least one monomer of the formula (I) belowwhereR1═C1 to C4 alkoxy, R2═C1 to C4 alkyl, and m=0 to 2, and also(a2) 40 to 90 mol % of at least one further olefinically unsaturated monomer,and the copolymer (A) possesses a glass transition temperature Tg of at least −30° C. The present invention also relates to a method for producing a multicoat paint system using the coating composition, and to the multicoat paint systems themselves.