Two-Component Aqueous Clearcoat for Footwear Substrates
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Solution Overview
Problem
Current methods for coating substrates, particularly in the footwear industry, fail to achieve a combination of high optical quality, mechanical resistance, flexibility, soil attraction resistance, and weathering stability, while also being environmentally friendly.
Innovation Solution
A method involving a two-component aqueous clearcoat composition is applied directly to the substrate, comprising a paint base with a polyurethane resin fraction and a curing component with hydrophilically modified polyisocyanate, which is cured at temperatures between 40°C to 100°C to produce a coating with excellent optical, mechanical, and weathering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods are used, then coating can be applied to substrate, but the coating fails to achieve a combination of high optical quality, mechanical resistance, flexibility, soil attraction resistance, and weathering stability
Solution Approach 1:
The patent employs a two-component aqueous clearcoat composition comprising a polyurethane resin fraction and a hydrophilically modified polyisocyanate curing component. This composite material system combines the flexibility and adhesion properties of polyurethane with the crosslinking capability of polyisocyanate, achieving a balance of optical quality, mechanical resistance, flexibility, and weathering stability that conventional single-component coatings cannot provide.
Solution Approach 2:
The patent specifies precise parameter ranges for the clearcoat composition, including polyurethane resin content (10-40% by weight), polyisocyanate content (5-20% by weight), and curing temperature (40-100°C). By optimizing these parameters, the coating achieves the desired combination of properties: high optical quality through controlled resin content, mechanical resistance through crosslinking density, and flexibility through molecular structure design.
2Strength
If high mechanical resistance is achieved in coating, then abrasion and stonechip resistance improve, but flexibility of the coating deteriorates
Solution Approach 1:
The patent achieves the balance between mechanical resistance and flexibility by carefully controlling the molecular weight and structure of the polyurethane resin fraction, specifying glass transition temperature ranges and melting transition temperatures. The hydrophilic modification of polyisocyanate and the controlled crosslinking density further adjust the coating's mechanical properties, allowing high abrasion resistance while maintaining the flexibility needed for deformable substrates like foam soles.
Solution Approach 2:
The two-component system combines linear polyurethane chains (providing flexibility) with crosslinked polyisocyanate networks (providing mechanical resistance). This composite structure at the molecular level allows the coating to simultaneously exhibit high strength properties and elastic deformability, resolving the contradiction between hardness and flexibility.
3Object-affected harmful factors
If aqueous clearcoat composition is used, then environmental profile improves, but achieving high optical quality and mechanical stability becomes more difficult
Solution Approach 1:
The patent achieves high optical quality and mechanical stability in an environmentally friendly aqueous system by precisely controlling the composition parameters: polyurethane resin content (10-40%), polyisocyanate content (5-20%), and auxiliary additives (0.1-5%). The controlled crosslinking reaction and film formation process in aqueous medium produce a coating with excellent optical properties (high gloss, clarity) and mechanical stability, matching or exceeding conventional solvent-based systems while eliminating harmful organic solvents.
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 resulting coating exhibits high matting effect, mechanical resistance, flexibility, soil attraction resistance, and outstanding weathering stability, enhancing the durability and appearance of substrates like foam soles while maintaining an excellent environmental profile.
Implementation Method 1
applying an aqueous clearcoat material (k) directly to the substrate (S) and subsequently curing the applied clearcoat material (k), the clearcoat material (k) being a two-component coating composition comprising (k.1) a paint base component comprising (1) at least one aqueous dispersion comprising water and a polyurethane resin fraction consisting of at least one polyurethane resin... (k.2) a curing component comprising (2) at least one hydrophilically modified polyisocyanate
Data Source
AI summary
A method for producing a coating on a substrate. The method includes producing a clearcoat directly on the substrate by applying an aqueous clearcoat material directly to the substrate. The method further includes curing the applied clearcoat material, the clearcoat material being a two-component coating composition. Also disclosed are coatings produced according to the method and their uses.