Hook Fastener Monofilaments with Elastomer for Fibrillation Resistance

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Solution Overview

Problem

Hook-and-loop fasteners with polybutylene terephthalate-based polyester monofilaments experience fibrillation and loss of engagement strength due to repeated engagement and peeling, leading to decreased durability and functionality, especially in applications with high frequency of use.

Innovation Solution

Incorporating 0.2 to 8% by mass of polyester elastomer into the polybutylene terephthalate-based polyester monofilaments for the hook engagement elements, blended through a process called blend spinning, which suppresses fibrillation and maintains engagement strength, and using a woven fabric structure with heat fusible multifilament yarns for the base fabric to secure the monofilaments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a monofilament formed of polyethylene terephthalate-based polyester is used as the hook engagement element, then high engagement force is obtained due to rigidity, but the loop engagement element is likely to be cut and the hook is elongated and deformed under impact load

Engineering Contradiction:
Improveengagement forceVSAvoidresistance to cutting and deformation
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The patent uses a composite structure consisting of a polybutylene terephthalate-based polyester monofilament core providing flexibility and a polyethylene terephthalate-based polyester sheath providing rigidity. This composite material combines the advantages of both materials to achieve high engagement force while preventing loop cutting and hook deformation under impact load.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different parts of the hook engagement element: the inner core uses polybutylene terephthalate for flexibility and shock absorption, while the outer sheath uses polyethylene terephthalate for rigidity and engagement force, creating local quality differentiation within the single filament.

Inventive Principle:
Principle #3Local quality

2Force

If a monofilament formed of polyethylene terephthalate-based polyester is used as the hook engagement element, then high engagement force is obtained, but the touch on the skin is poor and flexibility is reduced

Engineering Contradiction:
Improveengagement forceVSAvoidskin comfort and flexibility
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent creates a composite monofilament with polybutylene terephthalate core providing flexibility and soft touch, and polyethylene terephthalate sheath providing engagement force, thereby achieving both high engagement force and skin comfort.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent differentiates material properties within the filament structure: the inner core material contacts the skin and provides flexibility and comfort, while the outer sheath material provides engagement force, creating local quality differentiation.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If a monofilament formed of polybutylene terephthalate-based polyester is used as the hook engagement element, then flexibility and skin comfort are improved, but the monofilament fibrillates when engagement and peeling are frequently repeated

Engineering Contradiction:
Improveflexibility and skin comfortVSAvoidresistance to fibrillation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite structure where the polybutylene terephthalate core provides flexibility and skin comfort, while the polyethylene terephthalate sheath prevents fibrillation during repeated engagement and peeling, combining the advantages of both materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different functional materials to different regions of the filament: the core material provides flexibility and comfort where needed, while the sheath material provides fibrillation resistance at the outer surface during repeated use.

Inventive Principle:
Principle #3Local quality

4Ease of operation

If a polyamide-based monofilament is used as the hook engagement element, then good flexibility is obtained, but the fastener is waved by water absorption and heat, and dyeability differs from polyester clothing

Engineering Contradiction:
ImproveflexibilityVSAvoiddimensional stability and dyeability consistency
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent changes the material composition parameters by using polyethylene terephthalate and polybutylene terephthalate instead of polyamide, thereby eliminating water absorption and heat-induced waving while maintaining flexibility through the elastomer component, and achieving consistent dyeability with polyester clothing.

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 addition of polyester elastomer significantly reduces fibrillation and maintains high engagement strength even after repeated use, ensuring the hook-and-loop fastener's functionality and flexibility, while maintaining dyeability and suitability for skin contact applications.

Implementation Method 1

since the monofilament is flexible, it easily keeps the hook shape for a long time, easily rises even when the engagement element falls down

Methodology Applied
Scientific EffectElastic recovery: Elasticity

Implementation Method 2

using a woven fabric structure with heat fusible multifilament yarns for the base fabric to secure the monofilaments

Methodology Applied
Scientific EffectThermal bonding: Melting

Data Source

PatentEP3881709B1Fabric touch fastener having hook-shaped engagement elements
Publication Date: 2024.01.03 KURARAY FASTENING CO LTD
  • EP3881709B1 patent drawingFigure 1~2

AI summary

Disclosed is a hook-and-loop fastener including a base fabric having existing on a surface thereof a plurality of hook engagement elements, wherein monofilaments constituting the hook engagement elements are formed of a polybutylene terephthalate-based polyester containing 0.2 to 8% by mass of a polyester elastomer. The hook-and-loop fastener is made of a woven fabric, and the hook engagement element has excellent engagement strength and resistance to fibrillation, and has a gentle skin touch and excellent flexibility.