Cooling Sheet Adhesive Layer Composition Seepage Control

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Solution Overview

Problem

Conventional cooling sheets with high water content in the adhesive layer face issues of seepage and spread unevenness, which are not adequately addressed by existing technologies.

Innovation Solution

The method involves mixing a composition containing water, alum, sodium edetate, polyacrylic acid, and neutralized polyacrylic acid to achieve specific content ratios and a mixing temperature of 5 to 23°C, resulting in an adhesive layer composition that suppresses seepage and spread unevenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the water content in the adhesive layer is increased to enhance cooling performance, then cooling power and cooling duration are improved, but seepage of the adhesive layer occurs during storage and use

Engineering Contradiction:
Improvewater contentVSAvoidseepage suppression
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive layer by incorporating specific ratios of water-soluble polymer (0.1-10% by mass), alum (0.01-1% by mass), and sodium edetate (0.01-0.5% by mass). This parameter optimization allows the adhesive layer to maintain high water content (60-98% by mass) while preventing seepage through controlled gel network formation and metal ion coordination.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive layer system combining water-soluble polymer, alum, sodium edetate, and water. The water-soluble polymer forms a gel network that physically entraps water, while alum and sodium edetate create chemical crosslinks that further stabilize the structure. This composite approach enables high water content without seepage or spread unevenness.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the water-soluble polymer content is increased to suppress seepage, then seepage is reduced, but spread unevenness occurs in the adhesive layer

Engineering Contradiction:
Improveseepage suppressionVSAvoidspread uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the water-soluble polymer content to a specific range (0.1-10% by mass relative to total adhesive layer mass) and combines it with alum (0.01-1% by mass) and sodium edetate (0.01-0.5% by mass). This balanced parameter setting provides sufficient viscosity for uniform spreading during application while maintaining seepage suppression during storage and use.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces alum and sodium edetate as intermediary substances that mediate between the water-soluble polymer and water. These intermediaries form crosslinked gel structures that provide mechanical stability and prevent seepage without interfering with the uniform spreading of the adhesive layer during application.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If conventional aqueous adhesive formulations are used with high water content, then cooling action is enhanced, but the adhesive layer becomes unstable and seeps through the backing layer

Engineering Contradiction:
Improvewater contentVSAvoidadhesive layer stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent develops a composite adhesive formulation containing water-soluble polymer, alum, sodium edetate, and water in specifically controlled ratios. The water-soluble polymer creates a gel matrix that stabilizes the high water content, while alum and sodium edetate form crosslinked structures that prevent the adhesive layer from becoming unstable or seeping through the backing layer during storage and use.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters by incorporating alum (0.01-1% by mass) and sodium edetate (0.01-0.5% by mass) into the aqueous adhesive system. These parameter changes create a stable gel network that maintains structural integrity even at high water contents (60-98% by mass), preventing composition instability and seepage.

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

This approach allows for the production of cooling sheets with high water content (up to 98.24% by mass) while effectively preventing seepage and spread unevenness, thereby enhancing cooling performance and durability.

Implementation Method 1

an alum and sodium edetate which form a complex with each other

Methodology Applied
Scientific EffectComplex formation: Chemical Bonding

Implementation Method 2

sodium edetate which forms a complex with aluminum ions

Methodology Applied
Scientific EffectChelation:

Implementation Method 3

a water-soluble polymer, water, and the like are blended in an adhesive layer

Methodology Applied
Scientific EffectHydrogen bonding:

Implementation Method 4

a water-soluble polymer compound for the purpose of providing a water-containing patch having high water content

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Data Source

PatentUS12297380B2Method for producing adhesive layer composition for producing cooling sheet, method for producing cooling sheet, and cooling sheet
Publication Date: 2025.05.13 HISAMITSU PHARM CO INC

AI summary

A method for producing an adhesive layer composition for producing a cooling sheet including a backing layer, an adhesive layer, and a liner layer, the method comprising the step of:mixing a composition to be mixed containing water, an alum, sodium edetate, a polyacrylic acid, and a neutralized polyacrylic acid such that a mixing temperature becomes 5 to 23° C., to obtain an adhesive layer composition, whereinin the composition to be mixed,a content of the water is 69 to 938.24% by mass relative to a total mass of the composition to be mixed,a content of the alum is 0.18 to 0.42% by mass relative to the total mass of the composition to be mixed,a content of the sodium edetate is 0.08 to 0.18% by mass relative to the total mass of the composition to be mixed, anda mass ratio between the content of the alum and the content of the sodium edetate (the content of the alum: the content of the sodium edetate) is 1:1 to 5.25:1.