Rubber Compound Abrasion Resistance Zinc Reduction
Solution Overview
Problem
The use of zinc compounds in rubber mixtures for tires poses environmental concerns due to zinc release and manufacturing issues like blocked vent valves, necessitating a reduction in zinc content without compromising vulcanizate properties or increasing production costs.
Innovation Solution
A rubber mixture with reduced zinc oxide content, utilizing a vulcanization system with a specific molar ratio of accelerator to sulfur, combined with diene rubbers and optional fillers, to achieve good abrasion properties and ecological benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zinc oxide is used as an activator in sulfur-crosslinkable rubber mixtures, then sufficient cross-linking and vulcanization are achieved, but zinc compounds release into the environment causing aquatic damage and zinc sulfide deposits block vent valves during tire manufacture
Solution Approach 1:
The patent removes zinc oxide from the rubber compound formulation, extracting the harmful substance while maintaining vulcanization functionality through alternative activators and optimized sulfur-accelerator systems. This eliminates zinc release into the environment and prevents zinc sulfide deposits in mold vent valves.
Solution Approach 2:
The patent changes the chemical composition parameters by replacing zinc oxide with alternative activator systems and optimizing the accelerator-to-sulfur molar ratio. This parameter change maintains cross-linking effectiveness while eliminating harmful zinc compounds from the formulation.
2Object-affected harmful factors
If zinc content is reduced in rubber mixtures, then environmental impact and manufacturing issues are reduced, but vulcanizate properties such as abrasion resistance may be compromised
Solution Approach 1:
The patent optimizes the accelerator-to-sulfur molar ratio parameter to compensate for reduced zinc content. By adjusting this critical parameter within the specified range, the patent maintains adequate cross-linking density and abrasion resistance without relying on high zinc concentrations.
Solution Approach 2:
The patent employs a composite activator system combining multiple accelerators and sulfur donors working synergistically. This composite approach replaces the single zinc oxide activator, maintaining vulcanization effectiveness and abrasion properties through the combined action of alternative substances.
3Object-affected harmful factors
If zinc oxide content is reduced, then ecological advantages are gained and sulfide deposits in vent valves are reduced, but heating times may be extended increasing production costs
Solution Approach 1:
The patent optimizes the accelerator-to-sulfur molar ratio and selects specific accelerator types that maintain appropriate curing kinetics without zinc oxide. This parameter optimization ensures heating times remain economically viable while achieving the ecological benefits of reduced zinc content.
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 excellent vulcanizate properties, particularly abrasion resistance, while reducing environmental impact and lowering production costs through shorter heating times and reduced sulfide deposits, thus enhancing the economic viability of the rubber mixture.
Implementation Method 1
In the vulcanization of sulphur-crosslinkable rubber mixtures, it is customary to use zinc oxide (ZnO) as an activator. By forming a complex with the sulphur, it is activated for vulcanisation and sufficient cross-linking is thus achieved.
Implementation Method 2
By forming a complex with the sulphur, it is activated for vulcanisation and sufficient cross-linking is thus achieved.
Implementation Method 3
It is assumed that large amounts of zinc are released into the environment, particularly as a result of abrasion from tires, especially from the tread.
Data Source
AI summary
The invention relates to a rubber compound, in particular for tire treads. The rubber compound contains: - at least one diene rubber and - 0 to 1.2 phr zinc oxide and - a vulcanization system comprising at least one accelerator and elemental sulfur and/or at least one sulfur-donating substance, wherein the molar ratio of accelerator to sulfur is 0.9 to 5, the total molar amount of sulfur consisting of elemental sulfur and the sulfur released by the sulfur-donating substances. At a comparatively low zinc content, the rubber compound exhibits improved vulcanizate properties, in particular improved abrasion resistance.