Stretchable Laminate Using Hydroentangled Non-Woven Fabric

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Solution Overview

Problem

Existing stretchable laminates often fail to achieve a balance between excellent elongation and breaking strength, and preactivation methods can damage or perforate non-woven fabrics, leading to undesirable performance.

Innovation Solution

A stretchable laminate comprising a long-fiber hydroentangled non-woven fabric layer and a styrene-based elastomer layer with intermediate and surface layers, bonded via ultrasonic welding or a pressure-sensitive adhesive, where the non-woven fabric has a basis weight of 25 gsm or less and an elongation of 50% or more at 5 N, and the elastomer layer has a thickness of 20 µm to 200 µm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If preactivation treatment is applied to non-woven fabric to improve elongation, then elongation is improved, but the non-woven fabric may be broken or perforated, reducing breaking strength

Engineering Contradiction:
ImproveelongationVSAvoidbreaking strength
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The non-woven fabric is subjected to preactivation treatment before bonding with the elastomer layer. This preliminary action loosens and stretches the fibers in advance, creating a more open structure that will elongate further when stretched during use. The preactivation is controlled to improve elongation while maintaining sufficient breaking strength by optimizing treatment parameters such as tension, temperature, and duration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes multiple parameters of the preactivation process including the basis weight of the non-woven fabric (25 gsm or less), the elongation at 5 N (50% or more), and the breaking strength (10 N or more). By carefully controlling these parameters and the bonding conditions with the elastomer layer, the invention achieves the desired balance between elongation and breaking strength without causing fabric damage.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If non-woven fabric with high elongation is used, then stretchability is improved, but breaking strength may be insufficient

Engineering Contradiction:
ImproveelongationVSAvoidbreaking strength
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The invention creates a composite structure consisting of a non-woven fabric layer and an elastomer layer bonded together. The non-woven fabric provides the base structure with controlled elongation properties, while the elastomer layer contributes additional elasticity and strength. This composite approach allows the laminate to achieve both high elongation (50% or more at 5 N) and sufficient breaking strength (10 N or more) that neither material could achieve alone.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional non-woven fabric is used in stretchable laminate, then manufacturing is simple, but elongation is insufficient to achieve desired stretchability

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelongation
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The non-woven fabric undergoes preactivation treatment during the manufacturing process, which loosens and stretches the fibers before the fabric is bonded to the elastomer layer. This preliminary action is integrated into the manufacturing workflow, allowing the fabric to achieve the required elongation (50% or more at 5 N) without adding significant complexity to the manufacturing process. The treatment parameters are optimized to maintain breaking strength while improving elongation.

Inventive Principle:
Principle #10Preliminary action

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 laminate achieves both excellent elongation and breaking strength while preventing appearance failures like holes, and can be manufactured at a lower cost, ensuring effective use in sanitary articles like diapers and masks.

Implementation Method 1

the non-woven fabric layer and the elastomer layer are bonded to each other by ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3960442B1Stretchable laminate and method for manufacturing same
Publication Date: 2024.05.22 NITTO DENKO CORP
  • EP3960442B1 patent drawingFigure 1~2
  • EP3960442B1 patent drawingFigure 3A~3B

AI summary

A problem to be solved by the invention is to provide a stretchable laminate achieving both of excellent elongation and an excellent breaking strength, and a method of manufacturing the laminate. A stretchable laminate (100) of the present invention includes non-woven fabric layers (20a, 20b) and an elastomer layer (10). The non-woven fabric layers (20a, 20b) are each a long-fiber hydroentangled non-woven fabric. The stretchable laminate achieving both of excellent elongation and an excellent breaking strength is obtained by using the long-fiber hydroentangled non-woven fabric, which is a non-woven fabric formed through the fixation of fibers formed by a spun-laid method by a hydroentangling method.