Colored PTFE Membrane with Gradient Lightness for Waterproofness

Solution Overview

Problem

Colored porous polytetrafluoroethylene (PTFE) membranes tend to deteriorate in waterproofness due to uniform colorant distribution, affecting their performance in electronic devices.

Innovation Solution

A porous PTFE membrane with a colored design where the absolute difference in lightness between principal surfaces is 1.0 or more, allowing a small amount of colorant on one surface, maintaining the original properties by reducing uneven coloring and enhancing adhesion and waterproofness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a colored porous PTFE membrane is used to reduce visibility and prevent damage, then the membrane becomes inconspicuous and less susceptible to damage, but waterproofness deteriorates due to uniform colorant distribution

Engineering Contradiction:

Improvevisibility and damage susceptibilityVSAvoidwaterproofness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating non-uniform colorant distribution within the membrane thickness. The colorant concentration varies from one surface to the other, with at least one surface having lower colorant concentration to maintain pore structure and waterproofness, while the overall membrane remains colored for inconspicuous appearance and damage prevention.

Inventive Principle:

Principle #3Local quality

2Shape

If a colored porous PTFE membrane is used to improve aesthetics, then the membrane becomes less noticeable, but adhesion properties deteriorate due to colorant presence

Engineering Contradiction:

Improveaesthetic appearanceVSAvoidadhesion

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The patent applies local quality by creating non-uniform colorant distribution within the membrane thickness. The colorant concentration varies from one surface to the other, with at least one surface having lower colorant concentration to maintain pore structure and waterproofness, while the overall membrane remains colored for inconspicuous appearance and damage prevention.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11702528B2Porous polytetrafluoroethylene membrane, gas-permeable membrane, and gas-permeable member

Publication Date: 2023.07.18 NITTO DENKO CORP

AI summary

Provided is a porous polytetrafluoroethylene membrane in which an absolute value of a difference in lightness between one principal surface and the other principal surface is 1.0 or more, where the lightness is lightness L* of CIE 1976 (L*, a*, b*) color space specified in JIS Z8781-4: 2013. The porous polytetrafluoroethylene membrane may be colored black or gray. The porous polytetrafluoroethylene membrane provided can have properties with a reduced coloring-induced deterioration.