Water-based Anti-corrosion Coating Composition for Thick Film Application
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Solution Overview
Problem
Existing water-based coating systems for protecting metal-containing substrates, such as intermodal cargo containers, are limited by their inability to apply thick, uniform coatings in a single step due to issues like prolonged wet times, non-uniform drying, and limited maximum coating thickness, necessitating multi-layer applications and increasing complexity and duration.
Innovation Solution
Aqueous coating composition comprising a copolymer of vinylidene chloride, vinyl chloride, alkyl (meth)acrylate, and aliphatic alpha-beta unsaturated carboxylic acids, combined with an aluminium salt of phosphoric acid modified with an alkaline earth metal oxide, a non-ionic surfactant, and an inorganic filler, which allows for a single-step application of thick coatings exceeding 300 µm with excellent finish and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based coating systems are used to protect metal substrates, then environmental friendliness is improved, but coating thickness and uniformity deteriorate due to prolonged wet times and non-uniform drying
Solution Approach 1:
The invention modifies the chemical composition parameters of the water-based coating by incorporating specific polymers (polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer), anti-corrosive pigments (barium phosphate, zinc phosphate), and functional additives to achieve both environmental friendliness and coating uniformity at thicknesses exceeding 300 µm
Solution Approach 2:
The coating composition uses a composite formulation combining multiple polymers, anti-corrosive pigments, fillers, and surfactants to create a synergistic system that maintains water-based environmental benefits while achieving the performance of traditional solvent-based coatings in terms of thickness and uniformity
2Productivity
If thick coatings are applied in a single step, then application duration is reduced, but coating quality deteriorates due to cracks and non-uniform drying
Solution Approach 1:
The coating formulation is pre-engineered with anti-corrosive pigments, polymers, and additives in specific proportions to prevent cracking and ensure uniform drying from the outset, allowing thick single-step application without requiring subsequent corrective layers
Solution Approach 2:
The invention adjusts critical parameters including polymer molecular weight, pigment particle size distribution, and additive concentrations to enable the coating to maintain structural integrity and uniformity at thicknesses exceeding 300 µm during single-step application
3Manufacturing precision
If multiple coating layers are applied to achieve required thickness, then coating quality is maintained, but application complexity and time increase
Solution Approach 1:
The invention combines multiple functional components (anti-corrosive protection, thick-film formation, crack prevention, and uniform drying) into a single integrated coating composition, eliminating the need for multiple separate coating layers and their associated intermediate drying steps
4Object-affected harmful factors
If water-based coatings are used, then health and safety are improved, but coating thickness capability deteriorates due to limited maximum thickness per application
Solution Approach 1:
The invention fundamentally changes the performance parameters of water-based coatings by optimizing polymer composition, pigment loading, and additive packages to achieve a maximum coating thickness capability of over 300 µm per application, matching or exceeding traditional solvent-based systems while maintaining health and safety benefits
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
Enables the expedited application of thick, crack-free coatings with enhanced corrosion protection, reducing application duration and complexity while maintaining a smooth, continuous film even at high thicknesses, thus addressing the limitations of prior art.
Implementation Method 1
the said copolymer (A) is stable against dehydrochlorination , in a manner such that the total chloride content of the solid residue of the aqueous latex, after thermal treatment at about 120°C for 2 hours, is of less than 1000 ppm
Implementation Method 2
the said copolymer (A) does not to undergo any significant crystallization upon heating, in a manner such that the ratio of (j) its crystallinity index (CI) after a thermal treatment involving heating at 60°C for 48 hours to (jj) its crystallinity index before such thermal treatment (CI after thermal treatment /CI before thermal treatment ) is less than 1.15
Implementation Method 3
at least one anti-corrosion pigment comprising an aluminium salt of a (poly)phosphoric acid modified with an alkaline earth metal oxide
Data Source
AI summary
The invention pertains to an aqueous coating composition comprising: - an aqueous latex of a copolymer consisting essentially of recurring units derived (i) from vinylidene chloride (VDC), (ii) from vinyl chloride (VC), (iii) from one or more than one alkyl (meth)acrylate having from 1 to 12 carbon atoms in the alkyl group [monomer (MA)] and (iv) from one or more than one aliphatic alpha-beta unsaturated carboxylic acids [monomer (AA)], the proportion of recurring units derived from monomer (AA) being of at least 1.0 wt %, with respect to the total weight of the copolymer [copolymer (A)], wherein: (A) the said copolymer (A) is stable against dehydrochlorination, in a manner such that the total chloride content of the solid residue of the aqueous latex, after thermal treatment at about 120°C for 2 hours, is of less than 1000 ppm, with respect to the total weight of the copolymer (A); (B) the said copolymer (A) does not to undergo any significant crystallization upon heating, in a manner such that the ratio of (j) its crystallinity index (CI) after a thermal treatment involving heating at 60°C for 48 hours to (jj) its crystallinity index before such thermal treatment (Clafter thermal treatment/CI before thermal treatment) is less than 1.15; and - at least one anti-corrosion pigment comprising an aluminium salt of a (poly)phosphoric acid modified with an alkaline earth metal oxide [pigment (P)]; - at least one non-ionic surfactant [surfactant (NS)]; and - at least one inorganic filler [filler (I)] different from pigment (P), in an amount such that the overall pigment volume concentration (PVC), comprehensive of pigment (P) and filler (I), is comprised from 20 to 40 % vol., when determined with respect to the dried coating composition.