Nonwoven Web Material with Polyethylene and Polypropylene Fiber Blend

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Solution Overview

Problem

Current disposable absorbent articles face challenges in achieving a balance between mechanical strength and tactile softness, particularly due to the differences in properties between polypropylene and polyethylene fibers, which affect the perception of softness and are prone to fraying and pilling.

Innovation Solution

A nonwoven web material is formed with polypropylene fibers for mechanical strength and polyethylene fibers for a slippery feel, where the polyethylene fibers are interlaced among the polypropylene fibers to create a surface layer that imparts a silky tactile feel while being contained within the web, using thermal bonding and hydrojetting to secure the fibers in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If polyethylene fibers are used to improve tactile softness and slippery feel, then the coefficient of friction decreases and pliability increases, but mechanical strength and stiffness decrease

Engineering Contradiction:

Improvetactile softnessVSAvoidmechanical strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent combines polyethylene fibers (providing tactile softness and slippery feel) with polypropylene fibers (providing mechanical strength and stiffness) in a single nonwoven web structure. This merging of different fiber types allows the material to simultaneously exhibit both the desired softness and the required structural integrity that neither fiber type could achieve alone.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If polyethylene fibers are used to improve tactile softness, then the coefficient of friction decreases, but the material becomes more prone to fraying and pilling

Engineering Contradiction:

Improvecoefficient of frictionVSAvoidresistance to fraying and pilling

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent merges polyethylene fibers with polypropylene fibers in an interlaced configuration where the stronger polypropylene fibers provide structural support that restrains the polyethylene fibers, preventing them from fraying and pilling while maintaining the low friction surface feel.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent applies thermal bonding and hydrojetting processes to pre-reinforce and secure the fiber structure before the material is subjected to use conditions that would cause fraying and pilling. This preliminary treatment creates strong bonding points and interlacing that prevent future degradation.

Inventive Principle:

Principle #10Preliminary action

3Strength

If polypropylene fibers are used to improve mechanical strength, then stiffness and strength increase, but the coefficient of friction increases and tactile softness decreases

Engineering Contradiction:

Improvemechanical strengthVSAvoidtactile softness

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent combines polypropylene fibers (providing mechanical strength) with polyethylene fibers (providing tactile softness) in a blended nonwoven structure. The polyethylene fibers are distributed throughout and on the surface of the web, providing the desired soft feel while the polypropylene fibers provide the structural backbone.

Inventive Principle:

Principle #5Merging (Combining)

4Ease of operation

If polyethylene fibers are used to improve tactile softness, then pliability increases, but cost increases compared to polypropylene

Engineering Contradiction:

ImprovepliabilityVSAvoidcost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent applies polyethylene fibers selectively to provide tactile softness where it is most needed (particularly at the surface), while using polypropylene fibers for the bulk structure where mechanical strength is required. This localized application of different fiber types optimizes performance while controlling costs by not using expensive polyethylene throughout the entire material.

Inventive Principle:

Principle #3Local quality

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 enhances the tactile softness of the nonwoven web material, reducing the likelihood of fraying and pilling, while maintaining structural integrity, thus improving consumer perception and product quality.

Implementation Method 1

using thermal bonding and hydrojetting to secure the fibers in place

Methodology Applied

Scientific EffectThermal bonding: Melting

Implementation Method 2

using thermal bonding and hydrojetting to secure the fibers in place

Methodology Applied

Scientific EffectHydrojetting: Jet

Data Source

PatentEP3004444B1Nonwoven web material having enhanced glide softness and good strength attributes, and method for manufacturing

Publication Date: 2017.12.20 PROCTER & GAMBLE CO

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AI summary

Nonwoven web materials formed of a first outer accumulation, a second outer accumulation, and an inner accumulation of fibers are disclosed. The outer accumulations of fibers may form respective first and second macroscopic outer web surfaces. The webs may bear a pattern of thermal bonds impressed on either or both of the first and second macroscopic surfaces, at which the fibers of the first accumulation are thermally bonded to fibers of the second accumulation. Fibers of the inner accumulation may be interlaced among the fibers of the first and/or second accumulations and be present at the first and/or second macroscopic outer web surfaces. A related method for manufacturing nonwoven web materials is also disclosed.