Composite Fiber Core-Sheath Structure for Moisture Absorption

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Solution Overview

Problem

Existing non-woven fabrics used in sanitary and cosmetic applications face challenges in maintaining hydrophilicity and absorption performance due to the washaway of hydrophilic emulsions when continuously exposed to moisture, leading to reduced absorption and cooling effects.

Innovation Solution

A composite fiber structure is developed, comprising a hydrophobic polyolefin-based core and a sheath of ethylene vinyl alcohol (EVOH) resin with polyethylene glycol (PEG) and an inorganic additive, which enhances moisture absorption and thermal conductivity, preventing water from penetrating the core and maintaining hydrophilicity while providing a cooling sensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a hydrophilic emulsion is applied to non-woven fabric to improve absorbency, then moisture absorption performance is improved, but the emulsion is washed away when continuously exposed to moisture, causing loss of hydrophilicity

Engineering Contradiction:

Improvemoisture absorption performanceVSAvoidhydrophilicity stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies composite materials by combining polyolefin-based resin (hydrophobic) with EVOH resin and PEG (hydrophilic) to form a composite fiber structure. This composite construction allows the fiber to simultaneously achieve high moisture absorption performance and maintain stable hydrophilicity through the synergistic effect of different material properties, preventing the washaway problem of single-component hydrophilic emulsions.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating a core-sheath structure where the core region (polyolefin-based resin) provides structural integrity and hydrophobicity, while the sheath region (EVOH resin with PEG) provides hydrophilicity and moisture absorption. This spatial differentiation of material properties allows different parts of the fiber to perform different functions, maintaining hydrophilicity stability while achieving high absorbency.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If post-processing with hydrophilic emulsion is used to improve absorbency, then moisture absorption is improved, but the process becomes complicated and productivity decreases

Engineering Contradiction:

Improvemoisture absorptionVSAvoidproduction efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent applies preliminary action by incorporating hydrophilic components (EVOH resin and PEG) directly into the fiber formation process itself, rather than applying hydrophilic emulsion as a subsequent post-processing step. This integration of hydrophilic properties during extrusion eliminates the need for separate coating or treatment processes, thereby maintaining high productivity while achieving excellent moisture absorption performance.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If hydrophilic agent is applied and dried to improve absorbency, then moisture absorption is improved, but hydrophilicity is lost when continuously absorbing moisture

Engineering Contradiction:

Improvemoisture absorptionVSAvoidhydrophilicity retention

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by carefully controlling the composition ratios and molecular structures of the hydrophilic components (EVOH resin with specific vinyl alcohol content and PEG with specific molecular weight) within the fiber structure. This optimization of material parameters ensures that the hydrophilic properties are inherently embedded in the fiber chemistry, allowing continuous moisture absorption without loss of hydrophilicity, as the hydrophilic groups remain stable and functional under repeated wetting conditions.

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 composite fiber non-woven fabric achieves high moisture absorption rates (550% to 1500%) and thermal conductivity (0.1 W/m·K or more), ensuring excellent absorbency and cool feeling performance, even after repeated exposure to moisture, and is suitable for use in sanitary and cosmetic applications.

Implementation Method 1

a sheath including an ethylene vinyl alcohol (EVOH) resin, and a polyethylene glycol (PEG)... An amount of the PEG in the sheath may be 1 part by weight to 10 parts by weight, with respect to 100 parts by weight of the EVOH resin

Methodology Applied

Scientific EffectHydrophilic absorption: Absorption (physical)

Implementation Method 2

a sheath including an ethylene vinyl alcohol (EVOH) resin, and a polyethylene glycol (PEG)... The non-woven fabric may have a thermal conductivity of about 0.1 W/m·K or more

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20230257912A1Highly absorbent composite fibre, highly absorbent non-woven fabric, and article comprising same

Publication Date: 2023.08.17 TORAY ADVANCED MATERIALS KOREA INC

AI summary

Disclosed are a highly absorbent composite fiber, a highly absorbent non-woven fabric, and an article including the non-woven fabric. The disclosed highly absorbent composite fiber includes: a core including a polyolefin-based resin; and a sheath including ethylene vinyl alcohol (EVOH) resin.