Flame Resistant Spun Yarns From Polysulfonamide and Modacrylic Blends

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Solution Overview

Problem

Polysulfonamide fibers offer good thermal resistance but have low tensile break strength, limiting their mechanical properties and arc protection performance in protective apparel.

Innovation Solution

A flame-resistant spun yarn comprising a mixture of polymeric staple fibers derived from 4,4'diaminodiphenyl sulfone and modacrylic fibers, with optional para-aramid and antistatic fibers, to enhance both thermal resistance and mechanical strength while maintaining arc protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polysulfonamide fiber is used to provide thermal resistance, then thermal resistance is improved, but tensile break strength deteriorates

Engineering Contradiction:
Improvethermal resistanceVSAvoidtensile break strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent applies composite materials by blending polysulfonamide fibers with modacrylic fibers in a spun yarn. The polysulfonamide component provides thermal resistance and flexibility, while the modacrylic component contributes tensile strength and flame resistance. This composite fiber approach resolves the contradiction by combining materials with complementary properties to achieve both thermal protection and mechanical strength in the final fabric.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If polysulfonamide fiber is used to improve flexibility, then ease of operation is improved, but tensile break strength deteriorates

Engineering Contradiction:
ImproveflexibilityVSAvoidtensile break strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The spun yarn combines polysulfonamide fibers (providing flexibility and low modulus) with modacrylic fibers (providing tensile strength). This composite structure allows the fabric to maintain flexibility for worker comfort while achieving adequate tensile strength for arc protection performance.

Inventive Principle:
Principle #40Composite materials

3Temperature

If higher content of polysulfonamide fiber is used to enhance thermal resistance, then thermal resistance is improved, but arc protection performance deteriorates

Engineering Contradiction:
Improvethermal resistanceVSAvoidarc protection performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent optimizes the fiber blend composition to balance thermal resistance and arc protection. The modacrylic component provides flame resistance and structural integrity needed for arc protection, while the polysulfonamide component contributes thermal resistance and flexibility. This composite approach ensures both thermal protection and reliable arc protection performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies optimal weight ratios of polysulfonamide to modacrylic fibers in the spun yarn to achieve the desired balance of properties. By controlling the composition parameters of the fiber blend, the patent optimizes both thermal resistance and arc protection performance simultaneously.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2181209B1Flame resistant spun staple yarns made from blends of fibers derived from diamino diphenyl sulfone and modacrylic fibers and fabrics and garments made therefrom and methods for making same
Publication Date: 2011.04.20 EI DU PONT DE NEMOURS & CO

AI summary

The invention concerns a flame-resistant spun staple yarns and fabrics and garments comprising these yarns and methods of making the same. The yarns have 25 to 80 parts by weight of a polymeric staple fiber containing a polymer or copolymer derived from a monomer selected from the group consisting of 4,4'diaminodiphenyl sulfone, 3,3'diaminodiphenyl sulfone, and mixtures thereof; and 20 to 75 parts by weight of a modacrylic fiber, based on 100 parts by weight of the polymeric fiber and the modacrylic fiber in the yarn.