Carboxylated Synthetic Elastomer Cross-Linking for Comfort and Cost
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Solution Overview
Problem
Current elastomeric articles, such as gloves and condoms, face challenges in achieving a balance between low modulus and high elongation at break while maintaining comfort and avoiding allergens, with existing synthetic polymers often being expensive or environmentally harmful.
Innovation Solution
A synthetic elastomeric article is produced using a cured product of a synthetic latex composition comprising a synthetic carboxylated polymer and a cross-linking composition with a negatively charged multivalent metal complex ion at a pH of at least 9.0, which forms cross-links between carboxyl groups, reducing the need for expensive cross-linking agents and minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If natural (polyisoprene) rubber is used to achieve favourable feel and comfort properties with good balance between modulus and elongation, then elasticity and comfort are improved, but allergen risk increases due to Type I allergy potential
Solution Approach 1:
The patent changes the chemical composition parameters by using synthetic carboxylated polymers (such as carboxylated nitrile butadiene rubber, carboxylated styrene butadiene rubber, or carboxylated polyisoprene) instead of natural polyisoprene rubber. This substitution maintains the desired elastic properties and comfort while eliminating the allergen risk associated with natural rubber proteins.
2Ease of operation
If expensive synthetic elastomeric polymers are used to achieve reasonable feel and comfort properties, then comfort is improved, but production cost increases making them unsuitable for low cost disposable articles
Solution Approach 1:
The patent optimizes the polymer selection by using carboxylated synthetic polymers that can be cross-linked with inexpensive multivalent metal ions. This approach achieves satisfactory comfort properties at lower cost compared to traditionally used expensive synthetic elastomers.
Solution Approach 2:
The patent utilizes chemical cross-linking reactions where multivalent metal ions form cross-links between carboxyl groups on polymer chains. This phase transition from linear to cross-linked polymer structure achieves the desired mechanical properties and comfort at reduced cost.
3Ease of manufacture
If reducing the thickness of elastomeric articles is done to reduce material cost, then cost is reduced, but defect risk increases due to poor film formation and lower endurance properties
Solution Approach 1:
The patent employs chemical cross-linking through multivalent metal ions that form a three-dimensional network within the polymer matrix. This cross-linking process occurs during film formation and curing, enabling the production of thin-walled articles with adequate mechanical strength and reduced defect risk.
Solution Approach 2:
The patent creates a composite structure by combining synthetic carboxylated polymer matrices with multivalent metal ion cross-links. This composite approach enhances the mechanical properties and film formation quality of thin-walled articles, allowing cost reduction through thinner walls while maintaining reliability.
4Strength
If traditional cross-linking agents (finely milled solid zinc oxide and/or sulphur) are used to cross-link synthetic polymers, then cross-linking is achieved, but feel and comfort properties are compromised and production cost increases
Solution Approach 1:
The patent employs aqueous multivalent metal ion solutions that cross-link carboxylated polymers through ionic interactions. This cross-linking mechanism occurs in the aqueous phase during film formation, avoiding the need for traditional solid cross-linking agents and their associated processing issues.
Solution Approach 2:
The patent replaces the mechanical mixing and distribution of finely milled solid cross-linking agents with a chemical solution-based cross-linking system. Multivalent metal ions in aqueous solution provide uniform cross-linking without the aggregation and distribution problems of solid particulate cross-linkers, improving feel and comfort properties.
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 solution provides elastomeric articles with excellent properties, including high elasticity and low modulus, while being cost-effective and environmentally friendly, with reduced allergen risk and improved comfort.
Implementation Method 1
a cross-linking composition comprising an aqueous solution of a negatively charged multivalent metal complex ion having a pH of at least 9.0
Data Source
AI summary
This application relates to synthetic elastomeric articles, such as gloves, comprising the cured product of a synthetic latex composition, the synthetic latex composition comprising a synthetic carboxylated polymer and a cross-linking composition, the cross-linking composition comprising an aqueous solution of a negatively charged multivalent metal complex ion having a pH of at least 9.0. Also described are compositions for forming the articles, and methods for making the articles, based on the use of the described cross-linking composition. The articles, compositions and methods contain a second cross-linking agent comprising either (a) sulphur and a sulphur donor, (b) a multivalent metal oxide or ionic cross-linking agent, (c) sulphur, a sulphur donor and an ionic cross-linking agent, or (d) sulphur donor.