Latex Composition Aging With pH Control for Allergy-Safe Strength
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Solution Overview
Problem
Existing dip-molded articles made from latex compositions, such as those containing synthetic polyisoprene and vulcanization accelerators, can cause delayed allergic reactions and have insufficient tensile strength, tensile elongation, and tear strength.
Innovation Solution
A method involving pH control during an aging process of a latex composition, using a sulfur-based vulcanizing agent, xanthogen compound, and pH adjusters like alkali hydroxides or ammonia, to maintain a pH of 9 or more after 12 hours, with aging at 5 to 60°C for 12 to 14 days.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a vulcanization accelerator is added to the latex composition to improve tensile strength and tear strength, then the mechanical properties are enhanced, but delayed (Type IV) allergic reactions are triggered when brought into contact with the human body
Solution Approach 1:
The patent removes the harmful vulcanization accelerator from the latex composition while maintaining the beneficial mechanical properties through alternative vulcanization methods using sulfur and xanthogen compounds, thereby eliminating delayed allergic reactions while preserving tensile and tear strength
Solution Approach 2:
The patent changes the chemical parameters of the vulcanization system by replacing traditional accelerator-based systems with a sulfur-xanthogen system controlled by specific pH levels (maintained at 9 or more during aging), achieving both safety and mechanical performance through parameter optimization
2Reliability
If the pH is controlled to 9 or more during aging to prevent allergic reactions and improve stability, then safety and stability are enhanced, but the aging process requires precise pH monitoring and adjustment which increases process complexity
Solution Approach 1:
The patent employs pH adjusters that automatically maintain the required pH level of 9 or more during the aging process, allowing the system to self-regulate and eliminate the need for complex external pH monitoring and control systems
3Strength
If natural rubber latex is used to provide good mechanical properties, then tensile strength and elasticity are improved, but proteins in the natural rubber latex cause immediate (Type I) allergic reactions
Solution Approach 1:
The patent changes the material composition from natural rubber latex containing proteins to synthetic polyisoprene latex that is protein-free, while compensating for any loss in mechanical properties through optimized vulcanization conditions and pH control during aging
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 produces a latex composition that results in molded films with enhanced stability, tensile strength, tensile elongation, and tear strength, avoiding allergic reactions and improving mechanical properties.
Implementation Method 1
a preparation step of adding a sulfur-based vulcanizing agent and a xanthogen compound to the conjugated diene polymer latex
Implementation Method 2
the pH of the latex composition after 12 hours from the start of aging in the aging step is controlled to 9 or more
Data Source
AI summary
A method for producing a latex composition, the method comprising a provision step of providing a conjugated diene polymer latex; a preparation step of adding a sulfur-based vulcanizing agent and a xanthogen compound to the conjugated diene polymer latex to prepare a latex composition before aging; and an aging step of, after the preparation of the latex composition before aging, aging the prepared latex composition before aging through storing of the latex composition at a temperature of 5 to 60° C. for 12 hours to 14 days, wherein the pH of the latex composition after 12 hours from the start of aging in the aging step is controlled to 9 or more.