Disc Brake Pad Underlayer Composition for Noise Suppression and Flowability

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Solution Overview

Problem

The use of uncrosslinked fluororubber in underlayer compositions for disc brake pads results in insufficient flowability during the manufacturing process due to crosslinking and curing, leading to challenges in producing uniform quality products.

Innovation Solution

An underlayer composition containing 5-15 weight % uncrosslinked fluororubber, 4-8 weight % phenol-based resin, and 0.3-2 weight % hexamethylenetetramine, which maintains flowability during heating and softening, preventing crosslinking and ensuring uniform product quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If uncrosslinked fluororubber is added to improve brake noise suppression, then vibration absorption performance is improved, but flowability during manufacturing deteriorates due to crosslinking and curing

Engineering Contradiction:
Improvebrake noise suppressionVSAvoidflowability during granulation
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by introducing a phenolic resin system with specific curing agents (ammonium polyphosphate, zinc borate, borax) that alter the crosslinking behavior of fluororubber. This parameter change allows the fluororubber to maintain flowability during granulation while still achieving crosslinking during brake operation for noise suppression

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by pre-mixing the fluororubber with phenolic resin and curing agents in specific ratios before the granulation process. This preliminary formulation ensures that crosslinking does not occur during manufacturing handling, preserving flowability while preparing the material for subsequent crosslinking during actual brake use

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If rubber component is heated to soften for granulation, then flowability is improved, but crosslinking and curing occur prematurely, reducing manufacturing precision

Engineering Contradiction:
ImproveflowabilityVSAvoidproduct uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the thermal and chemical parameters by using a phenolic resin-curing agent system that requires specific conditions (moisture, heat during braking) to activate crosslinking. This allows heating during granulation to soften the rubber without triggering premature crosslinking, maintaining both flowability and manufacturing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces phenolic resin and curing agents as intermediary substances that mediate between the fluororubber and the heating process. These intermediaries prevent direct crosslinking during granulation heating while still enabling rubber softening, thus preserving flowability without sacrificing product uniformity

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for the production of disc brake pads with excellent brake noise suppression and uniform quality, maintaining rubber flowability and preventing defects like blistering and cracking.

Implementation Method 1

the rubber component is heated to soften so as to make a flowability of the raw material mixture better when granulating the same

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

crosslinking and curing of hexamethylenetetramine, which is added as a curing agent in the phenol-based resin as the binder

Methodology Applied
Scientific EffectCrosslinking and curing: Chemical Bonding

Data Source

PatentEP3964546B1Disc brake pad underlayer composition and disc brake pad using same
Publication Date: 2024.05.01 NISSHINBO BRAKE INC
  • EP3964546B1 patent drawingFigure 1

AI summary

[Summary] [Object] To provide the underlayer composition for the disc brake pad, which may be applicable to the manufacturing process of softening the rubber by heating even if the uncrosslinked fluororubber in the underlayer composition and the disc brake pad with an excellent brake noise suppression effect. [Means to Resolve] To use the underlayer composition containing 5 - 15 weight % of the uncrosslinked fluororubber relative to the entire amount of the underlayer composition, 4 - 8 weight % of the phenol-based resin as the binder relative to the entire amount of the underlayer composition, and 0.3 - 2 weight % of the hexamethylenetetramine as the curing agent for the phenol-based resin relative to the entire amount of the underlayer composition.