Elastomeric Staining Detection via Copper Acetate Testing

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Solution Overview

Problem

Due to regulatory changes, elastomeric articles are susceptible to staining caused by residual carbamate accelerators reacting with metals like copper, leading to discoloration, especially upon contact with human skin or copper-based jewelry.

Innovation Solution

A rapid method involving contacting the elastomeric articles with a metal solution, such as a copper acetate solution, to determine residual carbamate levels through visual inspection or spectrophotometry, allowing for remedial actions to reduce staining propensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of accelerants is reduced or removed to comply with regulatory changes, then the safety and regulatory compliance of elastomeric articles is improved, but the articles become susceptible to staining when contacted with metals like copper

Engineering Contradiction:
Improveregulatory complianceVSAvoidstaining susceptibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by testing elastomeric articles with metal solutions (copper, cobalt, nickel) before they reach the consumer. This allows manufacturers to identify staining susceptibility early in the production process and take remedial actions such as adjusting accelerator levels or adding stabilizers to prevent staining before the product is finalized.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the metal solution test results to guide formulation adjustments. The staining test provides direct feedback about residual accelerator levels and their potential to cause staining, allowing manufacturers to modify the elastomeric article composition accordingly to prevent the harmful staining effect while maintaining regulatory compliance.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If accelerants are completely removed from the production process, then consumer safety is improved, but the manufacturing process becomes more complex and difficult to control

Engineering Contradiction:
Improveaccelerator residueVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying accelerator levels and composition in the elastomeric article formulation. Rather than completely removing accelerants, the method optimizes their concentration to achieve the desired balance between product performance, safety, and staining resistance, making the manufacturing process more controllable.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces metal solution testing as an intermediary step in the manufacturing process. This intermediary test provides a simple, standardized method to assess accelerator residue and staining susceptibility without requiring complex analytical equipment, thereby simplifying quality control while maintaining safety standards.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If accelerants are reduced to minimize staining, then staining susceptibility is decreased, but the crosslinking efficiency and strength of the elastomeric article may be compromised

Engineering Contradiction:
Improvestaining propensityVSAvoidcrosslinking strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent optimizes accelerator concentration parameters to achieve the minimum effective level needed for adequate crosslinking while minimizing staining. By carefully controlling accelerator levels and using the metal solution test to verify staining resistance, the method maintains sufficient crosslinking strength without excessive accelerator residue.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent may employ composite approaches by combining multiple accelerators or adding stabilizing agents to the elastomeric formulation. This allows the system to maintain effective crosslinking performance with reduced overall accelerator content, thereby reducing staining susceptibility while preserving mechanical strength.

Inventive Principle:
Principle #40Composite materials

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 effectively determines the susceptibility of elastomeric articles to staining and allows for immediate remedial actions during production, reducing the likelihood of staining and improving product quality.

Implementation Method 1

staining is being caused by a reaction between residual carbamate accelerators on the elastomeric article and a metal, such as copper

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

measuring an absorbance of the extract and copper acetate solution at a predetermined wavelength using spectrophotometry

Methodology Applied
Scientific EffectAbsorbance spectroscopy: Absorption Spectroscopy

Data Source

PatentEP4162268B1Method for determining residual carbamate compounds on an elastomeric article
Publication Date: 2025.05.14 KIMBERLY CLARK WORLDWIDE INC
  • EP4162268B1 patent drawingFigure 1~2
  • EP4162268B1 patent drawingFigure 3
  • EP4162268B1 patent drawing

AI summary

A method and process for determining the propensity of elastomeric articles to discolor or stain is provided. The elastomeric articles tested are generally crosslinked elastomeric articles containing accelerators, such as carbamates. Residual carbamates can cause staining when contacted with metal ions, such as copper. Tests are disclosed for determining the propensity of the elastomeric articles to stain or discolor. The process can include remediation steps for preventing future articles from staining.