Copper-Free Friction Material with High Binder and Alkaline Additives

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Solution Overview

Problem

Friction materials without copper components face challenges in maintaining strength and preventing rust, leading to easy sticking and noise issues due to corrosion.

Innovation Solution

A friction material composition with a binder content of 10% or more by mass, incorporating calcium hydroxide and zinc, and maintaining a pH of 11.7 or more, which enhances strength and rust prevention without using copper fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If copper fiber is removed from friction material to improve environmental friendliness, then the friction material becomes free from heavy metal pollution, but the strength of the friction material decreases and rust prevention capability deteriorates

Engineering Contradiction:
Improveenvironmental pollution from copperVSAvoidstrength of friction material
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters by removing copper fiber and adjusting the binder content to 10% or more by mass, while controlling pH to 11.7 or more through calcium hydroxide and zinc addition. This parameter change maintains strength without copper by creating a protective alkaline environment that prevents rust and maintains material integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system combining fiber base material, binder (10% or more), calcium hydroxide, and zinc. This composite structure replaces the copper fiber's protective function through the synergistic effect of the binder matrix and alkaline components, achieving both rust prevention and strength maintenance without heavy metals.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If copper fiber is removed from friction material, then the friction material becomes environmentally friendly, but corrosion-induced sticking and noise increase

Engineering Contradiction:
Improveheavy metal pollutionVSAvoidcorrosion-induced sticking and noise
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention applies preliminary anti-action by adding calcium hydroxide and zinc to create a protective alkaline environment (pH 11.7 or more) before corrosion can occur. This preliminary protective measure prevents rust formation on the rotor surface that would otherwise cause sticking and noise, addressing the corrosion problem proactively rather than reactively.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention introduces calcium hydroxide and zinc as intermediary substances that mediate between the friction material and the rotor surface. These intermediaries create a protective barrier that prevents direct contact between moisture and the rotor, eliminating corrosion-induced sticking and noise while maintaining environmental friendliness.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If binder content is increased to 10% or more to maintain strength without copper, then the strength of friction material is secured, but the complexity of material composition increases

Engineering Contradiction:
Improvestrength of friction materialVSAvoidcomplexity of material composition
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention simplifies the composition complexity by focusing on key parameter changes: binder content (10% or more), pH control (11.7 or more through calcium hydroxide and zinc). Rather than adding multiple complex components, the invention achieves strength maintenance through controlled adjustment of these fundamental parameters, creating a relatively simple yet effective formulation.

Inventive Principle:
Principle #35Parameter changes

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 effectively secures the strength of the friction material and significantly reduces corrosion-induced sticking and noise, achieving performance comparable to copper-containing materials.

Implementation Method 1

a content of calcium hydroxide is from 2% by mass to 6% by mass, a content of zinc is from 1% by mass to 5% by mass, and the friction material has pH of 11.7 or more

Methodology Applied
Scientific EffectpH control:

Data Source

PatentUS10190649B2Friction material
Publication Date: 2019.01.29 AKEBONO BRAKE IND CO LTD

AI summary

This friction material contains a fiber base material, a friction modifier and a binder. The content of copper in the friction material is not more than 0.5 mass % in terms of elemental copper, and the content of the binder is at least 10 mass %. Furthermore, the friction material contains calcium hydroxide and zinc, and has a pH of at least 11.7.