Water-Soluble Substrate Coating for Premature Dissolution

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Solution Overview

Problem

Water-soluble substrates used in packaging materials, such as pouches, often dissolve prematurely when exposed to small amounts of water or humidity, leading to leakage and stickiness issues, and fail to fully dissolve when intended, posing a challenge in their design and manufacturing.

Innovation Solution

A water-soluble substrate with a coating applied to at least one surface, where the weight ratio of coating to substrate is greater than 0.80, providing enhanced resistance to accidental water contact while ensuring rapid dissolution in aqueous solutions, using polymers like polyvinyl alcohol and incorporating flexible, water-insoluble materials for the coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the water-soluble substrate is made thinner to improve dissolution speed and reduce cost, then the dissolution performance is improved, but the resistance to accidental dissolution decreases

Engineering Contradiction:

Improvedissolution speedVSAvoidresistance to accidental dissolution

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The invention uses a composite structure combining a water-soluble substrate (such as PVA-based film) with a water-insoluble barrier coating layer. This composite material allows the substrate to maintain thinness for fast dissolution while the coating provides protection against accidental water exposure, resolving the contradiction between dissolution speed and resistance to premature dissolution.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The barrier coating is applied selectively to the surface of the water-soluble substrate, creating a localized protective layer only where needed to prevent accidental dissolution. The bulk substrate remains thin and highly soluble, allowing rapid dissolution when intended. This local differentiation of properties resolves the contradiction between needing protection and needing fast dissolution.

Inventive Principle:

Principle #3Local quality

2Reliability

If a barrier coating is applied to the water-soluble substrate to prevent premature dissolution, then the resistance to accidental dissolution is improved, but the substrate may fail to dissolve fully when intended

Engineering Contradiction:

Improveresistance to accidental dissolutionVSAvoidcomplete dissolution

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention carefully controls the parameters of the barrier coating, including its thickness, composition, and porosity, to ensure it provides sufficient protection against accidental dissolution while allowing complete dissolution when exposed to adequate water during intended use. The coating is designed with specific properties that enable this dual behavior.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The barrier coating is applied as a surface layer only, leaving the bulk substrate intact and fully soluble. This localized coating approach ensures that the coating provides protection where needed while the majority of the substrate remains capable of complete dissolution, preventing the coating from interfering with the overall dissolution process.

Inventive Principle:

Principle #3Local quality

3Reliability

If the coating weight ratio is increased to improve resistance to dissolution, then the protection against accidental water contact is improved, but the substrate may become less soluble

Engineering Contradiction:

Improveresistance to dissolutionVSAvoidsolubility

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention optimizes the coating weight ratio and composition parameters to achieve the minimum effective protection against accidental dissolution while maintaining sufficient solubility. By carefully controlling these parameters, the coating provides necessary protection without excessively interfering with the substrate's ability to dissolve when intended.

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 substrate exhibits improved resistance to dissolution upon accidental water exposure without compromising its ability to quickly dissolve in water, addressing the issues of premature dissolution and leakage, and maintaining solubility when immersed in rinse or wash water.

Implementation Method 1

The coating is water-insoluble and provides a barrier to water penetration

Methodology Applied

Scientific EffectHydrophobe: Hydrophobe

Implementation Method 2

water-soluble substrate... can subsequently dissolve very quickly when immersed in an aqueous solution

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS8628844B2Water-soluble substrate with resistance to dissolution prior to being immersed in water

Publication Date: 2014.01.14 PROCTER & GAMBLE CO

AI summary

A water-soluble substrate, and more particularly a water-soluble substrate that is resistant to contact with small amounts of water, and methods of making the same are disclosed. A coating which is less water-soluble than the water-soluble substrate and in the form of particles, is applied to and substantially covers at least one surface of the water-soluble substrate. The weight ratio of coating to water-soluble substrate is higher than 0.8. Articles, such as pouches, made from the water-soluble substrate, are also disclosed herein.