Wet Wipe Preservative System for Sensitive Skin

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Solution Overview

Problem

Existing wet wipes face a challenge in balancing effective cleaning with skin gentleness, as chemical compounds required for cleaning and preservation can be harsh on human skin, particularly for infants and young children, and current preservative systems may not meet regulatory standards for microbial growth limits.

Innovation Solution

A cleansing composition for wet wipes is developed, incorporating a preservative system that includes a preservative enhancing agent such as caprylyl glycol or sorbitan caprylate, combined with a preservative like sodium benzoate, and a low pH buffering system, which enhances antimicrobial performance while being mild on the skin, achieved by dissolving preservatives in water, adding a rheology modifier, emulsifier, and citric acid to create a pH less than 4.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional preservative compounds are used to meet regulatory standards for microbial growth limits, then antimicrobial performance is improved, but skin gentleness deteriorates

Engineering Contradiction:
Improveantimicrobial performanceVSAvoidskin irritation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the pH parameter of the cleansing composition to a low pH range (pH 2-4), which fundamentally alters the antimicrobial mechanism from relying on harsh preservative compounds to relying on the acidic environment itself. This parameter change enables meeting regulatory antimicrobial standards while using milder preservative compounds at lower concentrations, thus reducing skin irritation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite preservative system combining multiple components: preservative compounds (benzoic acid, sorbic acid, or their salts), chelating agents (EDTA, citric acid), and buffering agents. This composite approach synergistically enhances antimicrobial performance through the low pH environment while allowing reduced concentrations of individual preservative compounds, thereby maintaining effectiveness while improving skin gentleness.

Inventive Principle:
Principle #40Composite materials

2Reliability

If higher concentrations of preservative compounds are used to ensure antimicrobial effectiveness, then reliability is improved, but the mildness on skin deteriorates

Engineering Contradiction:
Improveantimicrobial effectivenessVSAvoidskin sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By changing the pH parameter to a low acidic range (pH 2-4), the patent reduces the required concentration of preservative compounds from traditional high levels to lower levels (e.g., benzoic acid 0.1-5%, sorbic acid 0.1-5%). The acidic pH environment itself provides antimicrobial action, allowing effective preservative concentrations that are gentle on sensitive skin while maintaining regulatory compliance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces chelating agents (EDTA, citric acid) and buffering agents as intermediaries that work synergistically with preservative compounds. These intermediaries enhance the antimicrobial effectiveness of lower preservative concentrations by chelating metal ions that could otherwise promote microbial growth and by maintaining the low pH environment, thus enabling reduced preservative levels that are gentler on skin.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If effective cleaning compounds are used to achieve cleaning performance, then cleaning effectiveness is improved, but skin gentleness deteriorates

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidskin harshness
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the pH parameter to a low acidic range (pH 2-4), which provides inherent antimicrobial and cleaning effectiveness without requiring harsh alkaline cleaning compounds. The acidic environment effectively removes soils and kills microbes while being gentler on skin compared to traditional high-pH cleaning formulations, thus improving skin gentleness while maintaining cleaning effectiveness.

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 composition achieves improved antimicrobial performance with lower preservative concentrations, ensuring effective cleaning while being gentle on the skin and meeting regulatory standards for microbial growth, making it suitable for use on sensitive skin areas like those of infants.

Implementation Method 1

The cleansing composition comprises a preservative system for limiting the growth of microbes... a preservative enhancing agent... a preservative... wherein the cleansing composition has a pH less than about 4

Methodology Applied
Scientific EffectPreservative: Preservative

Implementation Method 2

adding citric acid to the solution... wherein the cleansing composition has a pH less than about 4

Methodology Applied
Scientific EffectpH buffering:

Data Source

PatentUS10779533B2Cleansing composition having a preservative system and a wet wipe comprising the clean compositions
Publication Date: 2020.09.22 PROCTER & GAMBLE CO

AI summary

A wet wipe includes a cleansing composition and a substrate. The cleansing composition includes a preservative enhancing agent selected from the group consisting of caprylyl glycol; caprylyl glyceryl ether; glyceryl caprylate; sorbitan caprylate; ethylhyexyl glycerin, and combinations thereof. The cleansing composition includes a preservative selected from the group consisting of benzoic acid; lactic acid; sorbic acid; malic acid; maleic acid, and combinations thereof. The cleansing composition has a pH less than about 4. A method of making the cleansing composition may include dissolving one or more preservatives with water to form a solution; adding a rheology modifier to the solution; adding an emulsifier to the solution; adding a preservative enhancing agent to the solution; and adding citric acid to the solution.