Polyimide Surface Treatment via Covalent Resin Bonding

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Solution Overview

Problem

Existing methods for making polyimide surfaces hydrophilic or hydrophobic, such as those involving ozone treatment, pose safety risks due to the use of flammable materials and toxic ozone, and may result in unstable surface modifications.

Innovation Solution

A surface treatment method involving the covalent bonding of a first resin with primary and secondary amino groups, and a second resin with (meth)acryloyl and hydrophilic or hydrophobic groups, to create a stable and safe hydrophilic or hydrophobic surface on polyimide materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If polyamic acid is heated to high temperature (200°C or more) in an ozone atmosphere to make polyimide hydrophilic, then the surface becomes hydrophilic, but fire or explosion may occur and ozone toxicity poses safety risks

Engineering Contradiction:
Improvehydrophilic surface propertyVSAvoidfire risk and ozone toxicity
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the harmful elements (ozone atmosphere and high temperature heating) from the surface treatment process. Instead, it uses a two-liquid method at room temperature that achieves hydrophilic modification without fire risk or toxic gas exposure, directly removing the dangerous components while preserving the desired functional outcome.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the fundamental parameters of the treatment process: temperature is reduced from 200°C or more to room temperature, and the chemical environment is changed from ozone atmosphere to aqueous/organic liquid phases. These parameter changes eliminate the fire hazard and toxicity while maintaining the ability to create hydrophilic surfaces through covalent bonding of amino-functionalized silane and acrylic acid.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If conventional surface treatment methods are used, then hydrophilic or hydrophobic properties can be achieved, but the surface modifications may be unstable and deteriorate over time

Engineering Contradiction:
Improvesurface property stabilityVSAvoiddurability of surface treatment
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The invention replaces physical adsorption or weak bonding mechanisms with covalent bonding mechanisms. The amino-functionalized silane forms strong covalent bonds with the polyimide surface, and acrylic acid subsequently bonds to the silane, creating a stable crosslinked network that resists deterioration over time, thereby substituting weak physical interactions with strong chemical bonds.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention creates a composite surface structure consisting of three components: the polyimide substrate, the amino-functionalized silane layer, and the acrylic acid layer. This multi-layer composite structure with covalent bonding between layers provides enhanced stability and durability compared to single-layer treatments, as each layer reinforces the others and the covalent bonds prevent delamination or degradation.

Inventive Principle:
Principle #40Composite materials

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 method effectively renders polyimide surfaces hydrophilic or hydrophobic while ensuring safe operation, with the surface treatments being stable and resistant to deterioration over time.

Implementation Method 1

covalently bonding first resin to the surface including polyimide of the treatment target

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

covalently bonding second resin to the first resin

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentEP3476464B1Surface treatment method, use of liquids in surface treatment, and surface-treated article
Publication Date: 2025.05.07 TOKYO OHKA KOGYO CO LTD
  • EP3476464B1 patent drawingFigure 1
  • EP3476464B1 patent drawingFigure 2
  • EP3476464B1 patent drawing

AI summary

To provide a surface treatment method capable of successfully making a treatment target including polyimide on a surface thereof hydrophilic or hydrophobic with a safe operation; a two-liquid type surface treatment liquid that can be suitably used for the surface treatment method; and a surface-treated polyimide product that can be obtained by the above-described surface treatment method. A first resin having a primary amino group and/or a hydroxyl group, and a secondary amino group is bonded to a surface of a treatment target including polyimide on a surface thereof, and then a second resin having a (meth)acryloyl group and/or a carbamoyl group, a hydrophilic group and/or a hydrophobic group is bonded to the first resin.