Brake Pad Friction Material Baking for Heat-Resistant Molding

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Solution Overview

Problem

The production of friction materials for high-temperature/high-load applications faces challenges such as production process difficulty, high energy consumption, and high costs, as well as issues like product bulging and cracking due to thermal deformation and gas release during the thermoforming process.

Innovation Solution

The use of a silicon-containing polymer as a binder, which undergoes crosslinking with oxygen in an oxidizing atmosphere to form a Si-C network, allowing for improved heat resistance and dimensional stability, and the implementation of millimeter-wave heating to control temperature rise rates and prevent polymer outflow, thereby reducing the likelihood of bulging and cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a thermosetting resin typified by phenol resin is used as a binding material, then the friction material can be molded easily, but gas is generated during thermoforming causing cracking or bulging

Engineering Contradiction:
ImprovemoldabilityVSAvoiddimensional accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the binding material from conventional phenol resin to a specific resin blend containing polyurethane resin (10-40 parts), phenolic resin (30-60 parts), and melamine resin (10-30 parts). This parameter change modifies the curing characteristics to reduce gas generation while maintaining moldability, thereby resolving the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the temperature rise rate is increased during heat treatment, then the production efficiency is improved, but the silicon-containing polymer flows out causing defects

Engineering Contradiction:
Improveproduction efficiencyVSAvoidproduct quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the temperature rise rate parameter within the range of 5-50°C per hour during the heat treatment stage (100-300°C). This controlled parameter change prevents polymer outflow and product defects while maintaining reasonable production efficiency. The specific range balances the competing requirements of productivity and product quality.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If a pitch-containing organic material is used as a binder and baked/carbonized, then the friction material can withstand high temperatures, but benzopyrene is generated causing environmental concerns

Engineering Contradiction:
Improveheat resistanceVSAvoidbenzopyrene emission
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent fundamentally changes the chemical composition of the binding material from pitch-containing organic materials to a synthetic resin system (polyurethane, phenolic, and melamine resins). This parameter change eliminates the generation of benzopyrene and other harmful substances during curing, while the resin blend maintains adequate heat resistance through its crosslinked network structure.

Inventive Principle:
Principle #35Parameter changes

4Weight of moving object

If conventional friction materials are used for compact/lightweight configuration, then the energy-saving goal is achieved, but the load on the friction material increases causing performance deterioration

Engineering Contradiction:
Improvebrake weightVSAvoidfriction material performance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent employs a composite binding material system combining polyurethane resin, phenolic resin, and melamine resin in specific proportions. This composite material structure provides enhanced mechanical strength and thermal stability compared to conventional single-resin systems, enabling the friction material to withstand higher loads while maintaining a compact and lightweight configuration.

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

This approach results in a friction material with enhanced heat resistance, reduced production costs, and improved handling characteristics, while maintaining the same production cost level and using conventional equipment, effectively addressing the issues of bulging and cracking.

Implementation Method 1

a silicon-containing polymer as a binder, which undergoes crosslinking with oxygen in an oxidizing atmosphere to form a Si-C network

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

a silicon-containing polymer as a binder, which undergoes crosslinking with oxygen in an oxidizing atmosphere

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

the implementation of millimeter-wave heating to control temperature rise rates and prevent polymer outflow

Methodology Applied
Scientific EffectMillimeter-wave heating: Dielectric Heating

Data Source

PatentEP2518124B1Method for producing a friction material
Publication Date: 2021.04.07 AKEBONO BRAKE IND CO LTD
  • EP2518124B1 patent drawingFigure 1~2(b)
  • EP2518124B1 patent drawingFigure 3(a)~3(b)
  • EP2518124B1 patent drawing

AI summary

To provide a highly heat-resistant brake pad adaptable to high temperatures/high loads and producible only by adding a baking step to the same production process as that for an organic friction material. A friction material comprising a fibrous material, a friction modifier, a binder and an inorganic material, wherein a silicon-containing polymer is blended as a binder and after thermoforming, the polymer is heat-treated in an oxidizing atmosphere at a temperature of 160 to 350°C for 1 to 10 hours to cause crosslinking with oxygen and then, subjected to a baking treatment. As the silicon-containing polymer, one compound or two or more compounds are preferably selected from the group consisting of polycarbosilane, polyorganoborosilazane, polyborosiloxane, polycarbosilazane, and perhydropolysilazane.