Acrylic-Epoxy Undercoat Composition for Finish-Coat Adhesion
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Solution Overview
Problem
Conventional anticorrosive coating compositions face issues with adhesiveness to finish coating films when there is a long interval between application and finish coating, and this can lead to complex coating processes and harsh working conditions.
Innovation Solution
A coating composition comprising an acryl resin with a solubility parameter of 9.0 to 12 and a weight average molecular weight of 1,000 to 95,000, and an epoxy resin with a solubility parameter of 10 to 12 and a weight average molecular weight of 250 to 2,500, along with optional amine-type curing agents and mica, to form a coating film with excellent adhesiveness and shrinkage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the interval between applying anticorrosive coating composition and finish coating is extended, then the coating process becomes simpler and working environment improves, but adhesiveness between coating film and finish coating deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the coating composition by incorporating specific components (polyisocyanate compound, polyester polyol, colloidal silica) that modify the coating film's properties to maintain adhesiveness over extended intervals. The polyisocyanate compound with NCO groups and the polyester polyol create a coating film with controlled solubility parameter and molecular weight that prevents shrinkage and maintains bonding capability.
Solution Approach 2:
The invention uses a composite coating composition combining multiple materials: polyisocyanate compound, polyester polyol, colloidal silica, and optional additives. This composite formulation creates synergistic effects where each component contributes to maintaining adhesiveness - the polyisocyanate provides crosslinking, the polyester polyol provides flexibility and adhesion, and colloidal silica provides structural stability and shrinkage resistance.
2Reliability
If the interval between applying anticorrosive coating composition and finish coating is shortened, then adhesiveness to finish coating is maintained, but coating process becomes complex and working environment becomes harsh
Solution Approach 1:
The invention modifies the coating film's physical and chemical parameters through selective ingredient composition to enable long-term stability. The controlled solubility parameter (9.0-12.0) and molecular weight (1,000-95,000) of the coating film, achieved through specific resin selection and配比, allow the film to remain stable and adhesive over extended periods without requiring immediate finish coating application.
3Strength
If conventional anticorrosive coating composition is used, then initial coating formation is achieved, but shrinkage occurs and solvent ooze-out affects finish coating adhesiveness over time
Solution Approach 1:
The invention employs a composite formulation where colloidal silica particles (5-50 wt%) provide structural framework and shrinkage resistance, while the polyisocyanate-polyester matrix provides flexibility and adhesion. This composite structure prevents the coating film from shrinking over time and blocks solvent ooze-out, maintaining both film integrity and finish coating adhesiveness.
Solution Approach 2:
The invention creates different functional zones within the coating film: the polyisocyanate-polyester matrix provides adhesion and flexibility, while the colloidal silica particles provide structural stability and shrinkage resistance. This local differentiation of material properties allows the coating film to simultaneously achieve good adhesion, dimensional stability, and solvent 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 maintains good adhesiveness to finish coating films even with extended intervals, inhibiting shrinkage and improving the coating process by preventing solvent ooze-out, thus enhancing the coating's durability and ease of application.
Implementation Method 1
an acryl resin; and an epoxy resin, wherein the acryl resin has a solubility parameter of 9.0 or more and 12 or less and a weight average molecular weight of 1,000 or more and 95,000 or less, and wherein the epoxy resin has a solubility parameter of 10 or more and 12 or less and a weight average molecular weight of 250 or more and 2,500 or less
Implementation Method 2
further comprising an amine-type curing agent
Data Source
AI summary
Provided is a coating composition for undercoating including: an acryl resin; and an epoxy resin, wherein the acryl resin has a solubility parameter of 9.0 or more and 12 or less and a weight average molecular weight of 1,000 or more and 95,000 or less, and wherein the epoxy resin has a solubility parameter of 10 or more and 12 or less and a weight average molecular weight of 250 or more and 2,500 or less.