Latex Elastomer Composition for Soft Yet Tear-Resistant Thin Films
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Solution Overview
Problem
Existing elastomeric articles, such as gloves and condoms, formed from synthetic polyisoprene, do not adequately balance tensile strength, tear resistance, and softness, leading to potential breakage and discomfort, while avoiding health issues associated with natural rubber.
Innovation Solution
Forming elastomeric articles with a combination of natural and synthetic rubber latexes, using sulfur donors like thiurams and dithiocarbamates, and additives like surfactants and antioxidants, to achieve high tensile strength, tear resistance, and low modulus, without elemental sulfur or zinc oxide, resulting in improved comfort and integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If synthetic polyisoprene is used to replace natural rubber, then health problems associated with natural rubber are avoided, but tensile strength and physical properties are insufficient
Solution Approach 1:
The patent uses a composite latex composition containing both natural rubber latex (5-50 parts) and synthetic polyisoprene latex (50-95 parts). This composite approach allows the article to avoid the allergic reactions associated with natural rubber while incorporating enough natural rubber to achieve the necessary tensile strength and physical properties that synthetic polyisoprene alone cannot provide.
2Ease of operation
If article thickness is reduced to achieve thin-film properties, then comfort and softness are improved, but tensile strength and tear resistance decrease
Solution Approach 1:
The patent employs specific curing agents (dithiocarbamates and/or thiurams) and controls the curing conditions to achieve optimal crosslinking density in the thin-film article. This parameter optimization allows the article to maintain high tensile strength and tear resistance even at thicknesses of 0.1 mm or less, while preserving the softness and comfort associated with thin-film construction.
3Strength
If conventional sulfur-based curing agents and zinc oxide are used, then tensile properties are improved, but health and environmental issues arise
Solution Approach 1:
The patent replaces conventional sulfur-based curing agents and zinc oxide with alternative curing agents including dithiocarbamates and/or thiurams. This substitution maintains the necessary tensile properties and crosslinking efficiency while eliminating the health and environmental concerns associated with traditional sulfur vulcanization systems.
Solution Approach 2:
The patent employs curable groups that form reversible or transient crosslinks during curing, allowing the material to achieve its desired physical properties without requiring permanent sulfur crosslinks. This approach enables effective curing while avoiding the harmful residues associated with conventional sulfur-based systems.
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 articles exhibit tensile strength greater than 30 MPa, tear strength of 2 N/mm, and modulus less than 1 MPa at 1 Hz, providing enhanced protection and comfort by maintaining film integrity and softness.
Implementation Method 1
using sulfur donors like thiurams and dithiocarbamates
Implementation Method 2
additives like surfactants and antioxidants
Implementation Method 3
additives like surfactants and antioxidants
Data Source
AI summary
The present disclosure provides compositions and products formed therefrom. In particular, the disclosure provides elastomeric latex articles, such as gloves and condoms, that can exhibit a desired combination of properties that can be correlated to suitable strength and softness.