Fibrous Pulp Elastomer Composite Yield Strain

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Solution Overview

Problem

Existing rubber-fibrous pulp composites fail to achieve a yield strain of at least 70%, yield stress of at least 4 MPa, and elongation at break of at least 200% when used in high strain applications, such as tires, due to decreased performance with higher aramid pulp concentrations, fiber dispersing agents, and interface modifiers.

Innovation Solution

A composition comprising an elastomer, 1 to 5 volume % of fibrous pulp with specific surface area and fiber characteristics, and 5 to 14 volume % of yield-strain promoters like fibers, needles, or platelets, which together achieve a yield strain of at least 70%, elongation at break of at least 200%, and yield stress of at least 4 MPa.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If higher aramid pulp concentrations are used to improve strength, then yield stress increases, but yield strain decreases

Engineering Contradiction:
Improveyield stressVSAvoidyield strain
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the physical and chemical parameters of the system by introducing yield-strain promoters with specific properties (fiber length 0.5-1.1mm, tensile modulus 6-130 GPa, tensile strength 1-3 GPa) and controlling pulp concentration at 1-5 volume%, thereby achieving both high yield stress (≥4 MPa) and high yield strain (≥70%) simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining elastomer matrix with fibrous pulp reinforcement and yield-strain promoters, where the synergistic interaction between different components enables both high strength and high elongation properties that cannot be achieved with single materials

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If fiber dispersing agents and interface modifiers are used to improve dispersion, then processing ease improves, but yield strain decreases

Engineering Contradiction:
Improveprocessing easeVSAvoidyield strain
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent eliminates or minimizes the use of fiber dispersing agents and interface modifiers by optimizing the pulp characteristics themselves (specific surface area 7-11 sq.m./g, fiber length 0.5-1.1 mm), thereby avoiding the negative side effects these additives have on yield strain while maintaining good processing ease

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If elastomeric composition is designed for high strength, then yield stress increases, but elongation at break decreases

Engineering Contradiction:
Improveyield stressVSAvoidelongation at break
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The patent achieves the breakthrough of simultaneously high yield stress (≥4 MPa) and high elongation at break (≥200%) by changing key parameters: controlling pulp concentration at 1-5 volume%, selecting specific pulp properties (specific surface area 7-11 sq.m./g, fiber length 0.5-1.1 mm), and incorporating 5-14 volume% yield-strain promoters with optimized characteristics

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent develops a multi-component composite elastomeric composition where the interaction between elastomer matrix, fibrous pulp (1-5 volume%), and yield-strain promoters (5-14 volume%) creates synergistic effects that enable both high strength and high extensibility, achieving yield strain ≥70% and elongation at break ≥200%

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS9074321B2Fibrous pulp and use thereof in a composite
Publication Date: 2015.07.07 DUPONT SAFETY & CONSTRUCTION INC

AI summary

A composition comprises (i) an elastomer, (ii) from 1 to 5 volume % of fibrous pulp, the pulp having a specific surface area of from 7 to 11 sq.m./g and the fiber having a fiber length of from 0.5 to 1.1 mm, a tensile modulus of from 2.5 to 130 GPa, and a tensile strength of from 1 to 3 GPa, and (iii) from 5 to 14 volume % of yield-strain promoter in the form of fibers, needles, powder or platelets, wherein the composition has a yield strain of at least 70%, an elongation at break of at least 200%, and a yield stress of at least 4 MPa.