Dry Hydrogel Sheet Preparation via Controlled Gelation and Drying

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Solution Overview

Problem

Conventional hydrogels face issues with decomposition due to high moisture content and dilution of active ingredients, leading to stability and distribution challenges.

Innovation Solution

A method for preparing a dry hydrogel sheet involves creating a cellulose ether dispersion solution, controlling its temperature between gelation and boiling points, applying it as a sheet, and drying it using techniques like hot air or infrared drying to achieve a low-moisture, uniformly thick product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional hydrogel is used with high moisture content, then flexibility and tissue-like properties are improved, but microbial decomposition and stability are worsened

Engineering Contradiction:

ImproveflexibilityVSAvoidstability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the moisture content parameter from high (conventional hydrogel) to low (dry state), transforming the hydrogel from a hydrated to a dry state to eliminate microbial decomposition while maintaining the polymer network structure that provides flexibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary drying of the hydrogel before application, removing excess moisture in advance to prevent microbial growth during storage and transport, while the hydrogel can reabsorb moisture upon contact with body fluids to regain flexibility

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If functional components are applied to conventional hydrogel, then therapeutic efficacy is improved, but concentration dilution and stability are worsened

Engineering Contradiction:

Improvefunctional component concentrationVSAvoidstability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the moisture content parameter to a low state, which prevents dilution of functional components and maintains their concentration and stability throughout the shelf life of the product

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The dry hydrogel sheet is designed as a stable, long-lasting product that maintains functional component integrity until use, eliminating the need for preservatives and refrigeration that would be required for conventional high-moisture hydrogels

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If hydrogel sheet is dried to reduce moisture content, then microbial decomposition is reduced, but manufacturing precision and uniformity are worsened

Engineering Contradiction:

ImprovestabilityVSAvoiduniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent utilizes the phase transition of water from liquid to vapor during controlled drying, transforming the hydrogel from a hydrated to a dry state while maintaining uniform moisture removal through controlled environmental conditions

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent replaces mechanical mixing and handling with a controlled drying process that uses thermal energy to uniformly remove moisture, avoiding mechanical disturbances that could create non-uniformities in the hydrogel sheet

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method results in a dry hydrogel sheet with reduced microbial decomposition risk, quantified active ingredient application, and improved uniformity, lowering distribution costs and enhancing product quality.

Implementation Method 1

applying the dispersion solution transferred to a coater as a sheet; preparing a hydrogel sheet by cooling the applied dispersion solution to induce gelation

Methodology Applied

Scientific EffectGelation: Gel

Implementation Method 2

drying the hydrogel sheet

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

drying it using techniques like hot air or infrared drying

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Data Source

PatentUS10765194B2Method of preparing dry hydrogel sheet and dry hydrogel sheet prepared by the same

Publication Date: 2020.09.08 LOTTE FINE CHEMICAL CO LTD

AI summary

The present invention relates to a method of preparing a dry hydrogel sheet including the steps of: preparing a cellulose ether dispersion solution; transferring the dispersion solution to a coater while maintaining the temperature of the dispersion solution in the range of a gelation temperature of the dispersion solution to a boiling point of a dispersion medium; applying the dispersion solution transferred to the coater as a sheet; preparing a hydrogel sheet by cooling the applied dispersion solution to induce gelation; and drying the hydrogel sheet. Since the dry hydrogel sheet prepared by the method has a low moisture content, it is possible to ensure the stability of active ingredients, quantify functional components to be applied to the dry hydrogel sheet, and ensure the uniformity of the surface appearance and thickness of the dry hydrogel sheet, which results in the improvement of the quality of a final product.