Anionic Aqueous Coating for Wood Grain Puffing
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Solution Overview
Problem
Waterborne wood coatings often cause 'grain puffing' on wood substrates due to moisture penetration, leading to a bumpy coating surface that reduces decorative effect, and existing solutions like cationic latex paints are expensive and limited in application.
Innovation Solution
An aqueous coating composition comprising anionic polymeric particles with a pH of less than 7.0 and nano-silica is applied to the wood substrate, forming an anti-grain-puffing coating that significantly reduces or eliminates grain puffing by blocking capillary penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If waterborne wood lacquer is applied to the wood substrate, then the coating provides environmental benefits and resource savings, but water penetrates into capillaries causing grain puffing and bumpy surface
Solution Approach 1:
The patent applies a sealing coating before the waterborne wood lacquer to prevent grain puffing. The sealing coating is applied in advance to block capillary pores, preventing water penetration when the lacquer is subsequently applied, thereby eliminating the grain puffing problem while maintaining environmental benefits
Solution Approach 2:
The sealing coating acts as an intermediary layer between the wood substrate and the waterborne wood lacquer. This intermediate layer blocks the capillary pores of the wood substrate, preventing direct contact between water in the lacquer and the wood capillaries, thus preventing grain puffing while allowing the lacquer to form a smooth decorative coating
2Manufacturing precision
If inorganic particles are used to fill and block capillaries, then grain puffing is reduced, but the coating complexity and material cost increase
Solution Approach 1:
The patent changes the pH parameter of the aqueous polymer latex to be less than 7.0 (acidic or neutral), which is different from conventional alkaline latexes. This parameter change enables the latex to effectively seal capillary pores without requiring additional inorganic particles, simplifying the coating composition while achieving grain puffing reduction
Solution Approach 2:
The patent creates a composite sealing system by combining aqueous polymer latex with specific pH modifiers (acids or acidifying agents). This composite material approach achieves effective capillary sealing through the synergistic interaction between the latex and pH modifiers, eliminating the need for complex multi-component systems with inorganic particles
3Manufacturing precision
If cationic aqueous latex paint is applied to form a barrier layer, then grain puffing is eliminated, but the cost and application limitations increase
Solution Approach 1:
Instead of using cationic latex as conventionally done, the patent inverts the approach by using anionic or non-ionic latex with acidic or neutral pH. This inverted approach achieves the same grain puffing prevention effect but with more versatile and cost-effective materials that are easier to manufacture and apply
Solution Approach 2:
The patent changes the pH parameter of the aqueous polymer latex to be less than 7.0, which fundamentally alters the chemical behavior of the latex. This parameter change enables the latex to effectively seal capillary pores without requiring the specialized cationic properties, thereby reducing cost and expanding application versatility
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 solution achieves superior grain puffing resistance and a smoother surface, with the treated article exhibiting at least 30% less surface roughness compared to coatings using alkaline anionic latex, enhancing the decorative effect while being environmentally friendly.
Implementation Method 1
water easily penetrates into capillaries of the substrate, causing the capillaries to swell
Implementation Method 2
the polymer particles comprise polymer having an anionic hydrophilic group on its molecule chain
Data Source
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AI summary
The present invention relates to aqueous coating compositions for forming an anti- grain-puffing coating, aqueous primers comprising the aqueous coating composition, and articles comprising the anti-grain-puffing coating. In particular, the aqueous coating composition comprises: (a) an aqueous dispersion of polymeric particles, wherein the polymer particles comprise polymer having an anionic hydrophilic group on its molecule chain, and the aqueous dispersion of polymeric particles has a pH of less than 7.0; and (b) an aqueous dispersion of nano-silica.