Conversion-Coated Metal Plate for Thermoplastic Resin Bonding
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Solution Overview
Problem
Conventional chemical conversion coatings for metal substrates used in composite members with non-condensed thermoplastic resins often result in insufficient adhesiveness and decreased bonding strength when exposed to chemical agents.
Innovation Solution
A chemical conversion coated metal sheet is developed with a coating film containing an ethylene-acrylic acid copolymer, colloidal silica, and a silane coupling agent, where the ethylene-acrylic acid copolymer has an acrylic acid content of 10 mass % or more and a melt flow rate of 80 g/10 min or less, enhancing both adhesiveness and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional chemical conversion coating is used on metal substrate for non-condensed thermoplastic resin bonding, then the coating provides basic adhesion, but the adhesiveness and bonding strength deteriorate when exposed to chemical agents
Solution Approach 1:
The patent applies composite materials principle by creating a multi-component coating film comprising colloidal silica, silane coupling agent, and polyolefin resin. This composite structure combines the adhesion benefits of silica-silane system with the chemical resistance and bonding capabilities of polyolefin resin, achieving both high adhesiveness and chemical resistance simultaneously
Solution Approach 2:
The patent applies parameter changes principle by optimizing specific parameters of the polyolefin resin including melt flow rate (5-100 g/10 min), weight average molecular weight (10,000-1,000,000), and resin content in the coating film (1-50 mass%). These parameter optimizations enable the coating to maintain appropriate viscosity for application while providing sufficient adhesion and chemical resistance
2Strength
If the acrylic acid content in ethylene-acrylic acid copolymer is increased to improve adhesiveness, then the bonding strength improves, but the melt flow rate increases which may affect coating quality
Solution Approach 1:
The patent applies parameter changes principle by precisely controlling multiple parameters of the ethylene-acrylic acid copolymer including acrylic acid content (10-40 mass%), melt flow rate (80-150 g/10 min), and weight average molecular weight. This multi-parameter optimization ensures the copolymer provides sufficient adhesion while maintaining appropriate coating characteristics
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 significantly improves the adhesiveness and chemical resistance of composite members, maintaining strong bonding even after immersion in chemical agents, making it suitable for various applications such as automotive and domestic appliance components.
Implementation Method 1
a chemical conversion coating film which is obtained by coating the metal substrate with a coating liquid that contains an ethylene-acrylic acid copolymer, colloidal silica, and a silane coupling agent
Implementation Method 2
a silane coupling agent, and that the ethylene-acrylic acid copolymer has an acrylic acid content of 10 mass % or more and a melt flow rate of 80 g/10 min or less
Implementation Method 3
a coating liquid that contains an ethylene-acrylic acid copolymer, colloidal silica, and a silane coupling agent
Data Source
AI summary
According to one aspect of the present invention, there is provided a chemical conversion coated metal sheet for non-condensed thermoplastic resin bonding, the chemical conversion coated metal sheet including a metal substrate and a chemical conversion coating film disposed on at least one surface of the metal substrate, in which the chemical conversion coating film is obtained by coating the metal substrate with a coating liquid that contains an ethylene-acrylic acid copolymer, colloidal silica, and a silane coupling agent. The ethylene-acrylic acid copolymer has an acrylic acid content of 10 mass % or more and a melt flow rate of 80 g/10 min or less.