Natural Rubber Stabilization via Preservative Aging
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Solution Overview
Problem
Natural rubber coagulum experiences reduction and variation in molecular weight and non-rubber component quality due to bacterial proliferation and decomposition during the standing step, leading to unstable physical properties in rubber compositions and tires.
Innovation Solution
Aging a hydrous natural rubber coagulum for three days or longer with a preservative like 1,2-benzisothiazoline-3-one, followed by washing and drying to stabilize non-rubber components and prevent molecular weight reduction, resulting in a rubber composition with enhanced mechanical properties and anti-aging characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If natural rubber coagulum is left standing in a wet condition for aging, then the coagulum undergoes maturation changes, but bacteria and microorganisms proliferate causing decomposition of non-rubber components and reduction in molecular weight
Solution Approach 1:
The patent applies preliminary action by adding preservatives to the natural rubber coagulum before the aging process begins. This preventive measure inhibits bacterial and microorganism proliferation during the subsequent standing period, allowing the coagulum to undergo maturation changes without decomposition of non-rubber components or reduction in molecular weight.
Solution Approach 2:
The patent uses preservatives as intermediary substances that mediate between the natural rubber coagulum and harmful microorganisms. These preservatives act as protective agents that prevent microbial attack on the coagulum during aging, enabling stable maturation while maintaining the integrity of non-rubber components.
2Stability of the object's composition
If natural rubber coagulum is stood for various periods, then aging effects vary, but physical properties show marked reduction and variation making targeted properties unobtainable
Solution Approach 1:
The patent applies preliminary action by establishing standardized aging conditions with controlled standing periods and preservative addition before the aging process. This pre-planned approach ensures that the coagulum undergoes consistent maturation changes, producing natural rubber with stable and predictable physical properties that meet targeted specifications.
Solution Approach 2:
The patent utilizes parameter changes by optimizing and controlling the standing period duration and preservative concentration during aging. By carefully adjusting these parameters, the patent achieves stable maturation effects that consistently produce natural rubber with desired physical properties, eliminating the variation problem associated with uncontrolled aging periods.
3Duration of action of stationary object
If preservatives are added to natural rubber latex, then stability in standing step is secured, but the addition amount must be controlled within 0.01 to 1.0% by mass to prevent adverse effects
Solution Approach 1:
The patent applies parameter changes by precisely controlling the preservative addition amount within the specific range of 0.01 to 1.0% by mass based on coagulum weight. This optimized parameter range ensures sufficient stability during standing while preventing adverse effects on natural rubber quality, achieving the desired balance between extended standing stability and maintained rubber quality.
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 stabilizes mechanical properties and anti-aging performance of natural rubber, improving modulus, tensile stress, and vulcanization acceleration, leading to better tire performance by maintaining non-rubber components' quality and preventing decomposition.
Implementation Method 1
natural rubber latices to which preservatives, fungicides and bacteriostatic agents are added for the purpose of inhibiting proteins and lipids which are non-rubber components in a natural rubber latex from being decomposed by microorganisms
Implementation Method 2
the maturation means standing the coagulum for a certain period of time in a wet condition, and the changing with the passage of time means a change in a molecular weight of an polyisoprene chain in the natural rubber coagulum and a change in the contents of non-rubber components such as proteins and lipids
Implementation Method 3
bacteria and microorganisms contained in the coagulum are proliferated and activated, and proteins and lipids which are non-rubber components in the natural rubber coagulum are decomposed thereby
Data Source
AI summary
The natural rubber of the present invention is natural rubber obtained by leaving standing for a prescribed period of time a hydrous coagulum obtained from a natural rubber latex to which a preservative is added and/or from a coagulum of a natural rubber latex to which a preservative is added and drying it. The natural rubber coagulum is inhibited from being changed in a molecular weight even in a standing step (aging) in a high moisture condition, whereby the natural rubber having stable mechanical properties is obtained. An isothiazoline base compound is used for the preservative. Further, a rubber composition containing the natural rubber is prepared, and a tire is produced by using the rubber composition.