PVDF Coating Liquid Adhesiveness via Composite Binder

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Solution Overview

Problem

Existing methods for forming coating films with polyvinylidene fluoride (PVDF) face challenges such as insufficient adhesiveness to base materials, complexity in material preparation, and increased number of treatment steps, limiting their application in achieving desired properties like non-tackiness, chemical resistance, and electrical conductivity.

Innovation Solution

A coating liquid containing a hydrophilic polymer, PVDF, and a polar solvent, with a concentration gradient of these components to enhance adhesiveness and functional properties, and the inclusion of an electrically conductive material to improve conductivity and stability, forming a coating film with excellent adhesiveness and functional properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PVDF is used as a coating material, then non-tackiness and chemical resistance are improved, but adhesiveness to base material deteriorates

Engineering Contradiction:
Improvenon-tackiness and chemical resistanceVSAvoidadhesiveness to base material
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention uses a composite coating material consisting of PVDF mixed with specific inorganic particles (such as silica, alumina, or titania) having a mean particle diameter of 0.1 to 10 μm. This composite structure allows the coating film to simultaneously exhibit the non-tackiness and chemical resistance of PVDF while the inorganic particles provide anchoring points that improve adhesiveness to the base material, thereby resolving the contradiction between these properties.

Inventive Principle:
Principle #40Composite materials

2Strength

If modified fluororesin with functional groups is used, then adhesiveness is improved, but material preparation complexity increases

Engineering Contradiction:
ImproveadhesivenessVSAvoidmaterial preparation complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Instead of chemically modifying the fluororesin structure, the invention changes the physical parameters of the coating system by incorporating inorganic particles with specific size ranges (0.1 to 10 μm mean diameter). This parameter-based approach improves adhesiveness through physical mechanisms such as mechanical interlocking and surface area increase, avoiding the complex chemical modification processes and reducing material preparation complexity.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If PVDF solution in NMP is used for electrode binding, then coating applicability is improved, but binding force of active materials is insufficient

Engineering Contradiction:
Improvecoating applicabilityVSAvoidbinding force of active materials
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention creates a composite binder system by combining PVDF dissolved in NMP with inorganic particles (silica, alumina, or titania) having a mean particle diameter of 0.1 to 10 μm. The inorganic particles serve as additional binding sites and structural support, enhancing the binding force of active materials while maintaining the excellent coating applicability provided by the PVDF-NMP solution system.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3187553B1Coating liquid, coating film, and composite material
Publication Date: 2019.12.25 DAINICHISEIKA COLOR & CHEMICALS MFG CO LTD

AI summary

There is provided a coating liquid capable of forming a coating film that is excellent in adhesiveness to the surface of a base material such as a metal, glass, or a resin even though the coating film contains PVDF which exhibits a remarkable non-tackiness and that can exhibit various desired functionalities such as non-tackiness, an antifouling property, chemical resistance, a sliding property, water repellency, electrical conductivity, an antifungal/antimicrobial property, and a deodorizing property. The coating liquid contains a polar solvent such as N,N-dimethylformamide or N-methyl-2-pyrrolidone, a hydrophilic polymer such as a chitosan derivative or a cellulose derivative, and polyvinylidene fluoride.