TRIAL PRODUCT VULKANOX 4060
INNOVATIVE TIRE ANTIDEGRADANTS
Aging processes in tires, which are caused by oxygen or heat, change the properties of the vulcanizates. Rubbers generally are subject to such changes that occur in the course of time that can lead to partial or complete destruction. Possible consequences are depolymerization, fatigue, brittleness, cracks and even disintegration. Ozone or dynamic stress (fatigue) lead to cracking on the surface of the tire. Antidegradants are chemicals which protect the vulcanizates against these damaging external influences. Depending on the chemical structure, they act against one or more of the aging processes mentioned. The major antidegradant for the tire industry is 4-N- (4-methylpentan-2-yl)-1-N-phenylbenzene-1,4-diamine (6PPD), which is sold under the LANXESS trademark Vulkanox® 4020.
Brand
VULKANOX®
UNDERSTANDING THE PROBLEM
The rise of 6PPD started in the 1960s, when tire manufacturers began using 6PPD to protect against oxygen, ozone and cracking. Today, 6PPD is used in almost all commercial tires, especially in the tire sidewalls and the tread compounds.
In recent years, the properties of 6PPD were studied with high intensity. As a consequence, 6PPD was self-classified as reprotoxic 1B in 2019.
During its use, 6PPD transforms into different other chemicals when it reacts with oxygen and ozone present in the environment. One transformation product, 6PPD-Quinone, which was discovered in December 2020 (Tian et al., 2021), is of special interest, as it was found to be acutely toxic to coho salmon. Tire wear particles may contain 6PPD-Quinone and can be washed into stormwater, which can then spread to rivers and other streams.
TRIAL PRODUCT VULKANOX® 4060
Developing a 6PPD alternative that maintains tire performance while meeting stringent environmental and safety standards is a challenging task. Based on lab results, LANXESS believes, that Vulkanox® 4060 which contains N,N’-Dicyclohexyl-1,4-phenylene diamine is a potential 6PPD replacement, as it shows similarly strong antioxidant and antiozonant performance results in rubber tests, while having a more favorable product safety profile. As a solid product, it can be dosed similarly as easy as 6PPD.
PERFORMANCE
Rubber components deteriorate over time due to environmental factors and regular use. This degradation manifests as oxidation, ozone-induced aging and mechanical stress cracking. Traditional solutions, such as 6PPD, though effective, have detrimental environmental impacts.
Vulkanox® 4060 is an innovative antioxidant for use in compounds based on diene rubbers such as NR, BR, SBR and their blends. Vulkanox® 4060 offers very good protection against oxidation, ozone attack, and flex cracking. The tensile test, aged for 28 days at 60 °C, shows the protection of CCPD against hot air aging: In the reference compound without antioxidant, the tensile strength is reduced by about 22%, whereas in compounds with CCPD the tensile strength is reduced by only 13%. CCPD shows similar tensile strength results than 6PPD.
Advantages of Vulkanox® 4060:
- Superior antioxidant properties: Provides exceptional resistance to oxidative aging
- Very good ozone protection: Shields rubber surfaces from ozone-induced damage
- Enhanced flex cracking resistance: Significantly reduces crack formation and growth due to mechanical stress
PRODUCT SAFETY
Vulkanox® 4060 is a trial product, meaning that its performance and safety profile is currently being tested. LANXESS targets global registration of Vulkanox® 4060. To ensure a fast and efficient registration process, LANXESS developed a roadmap covering all relevant studies, with a focus on hazard concerns of related chemicals. LANXESS already tested various properties of Vulkanox® 4060, especially with regard to effects on human health and the environment. These studies are required for the planned EU REACH registration.
Biodegradation is one of the most important factors in assessing the environmental fate of chemicals.
A recent OECD 301D guideline study demonstrates > 60% biodegradation of CCPD within 28 days. This result is sufficient to conclude under EU REACH that CCPD is not persistent in the environment and therefore does not exhibit the characteristics of a PBT, PMT, vPvB, or vPvM substance.
DEVELOPMENT STATUS
The Vulkanox® 4060 product is currently in the development stages. It is produced in pre-commercial scale in LANXESS production facilities. LANXESS’ plan is to ramp-up the production in the next years, which goes hand in hand with different product safety studies.
Further information, including amended or supplementary data on hazards associated with its use, will be compiled in the future.
FAQ
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