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Rubber Protection
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Vulnerabilities of Natural Rubber
Tire manufacturers blend into the tire polymer
certain chemical ingredients which inhibit damage from ozone and ultraviolet light, the
main environmental degradants of tires and all other types of synthetic and natural
rubbers. Ozone is an odorless gas, but is commonly thought of as the "electric train
smell". Though more severe in cities and manufacturing centers, ozone is part of the
air we breathe everywhere on earth. Hastened by the hazardous effects of UV light, ozone
eventually causes rubber to dry and become brittle no matter the locale.
Ultraviolet Light
The need to protect rubber against UV damage is
why tires are black. For this purpose, a common type of UV stabilizer called a
"competitive absorber" is used. Competitive absorbers work by capturing and
absorbing harmful UV light wave energy (instead of the adjacent molecule of tire
polymer..that's why it's called "competitive"). Competitive absorbers have the
added ability to convert harmful UV light wave energy into heat so it can dissipate
harmlessly. All tire manufacturers use the same competitive absorber, carbon
black...an extremely inexpensive compound. All other UV stabilizers are prohibitively
expensive. This is why tires are black and why tires are not available in designer
colors. All UV stabilizers are sacrificial, meaning they are gradually "used
up" to where they can no longer protect against UV damage. As carbon black loses the
ability to do its job, it turns gray. This is why rubber grays as it ages.
Ozone
Tire manufacturers use waxes to protect against ozone. When
tires are in use (regularly running up and down the road for example) they flex. Flexing
causes the protective waxes to migrate to the surface where they form a physical barrier
between the air (ozone and oxygen) and the tire polymer. This process...the waxes
migrating to the surface of the tire during flexing..is called "blooming". When
tires are not regularly used ( a parked RV, boat trailer, or classic car, etc), blooming
does not occur. Ozone begins eating away the protective wax and before long reaches the
tire polymer. Often by this time, the surface carbon black has lost its ability to protect
against UV. With UV light and ozone working in concert, degradation starts. The tire
dries, checks, and will eventually crack.
Other Degradants
Petrochemicals and silicone oils can remove the
protective waxes and increase the rate of degradation. Common automotive
"protectants" and "tire dressings" are typically devoid of UV
stabilizers of any type. They contain petrochemicals and/or silicone oils which dissolve
away the protective waxes and can actually aggress the sidewall. In the event of warranty
sidewall failure, one of the first things tire manufacturers look for is evidence of the
use of these types of products. When found, this is often cause for not warranting the
sidewall failure.
Hollyday Designs Rubber
Compound
We add only the bare essentials to our compund
to make the most stable and durable rubber possible for high-start use. Unlike tire
manufacturers, who do not require up to 500% elongation with a flat tension curve, we must
rely only on mother nature and stick to the purest latex rubber compound that we can get.
Less than one percent of the rubber in our compound is made up of ingredients other than
pure natural latex rubber. For this reason, using 303 Aerospace Protectant
to prevent premature oxidation and failure of your rubber is essential. This is the good
stuff. It can be used on any plastic or rubber material which is exposed to the elements,
including fiberglass gelcoat, and acrylic enamel clear coat car paint for extra
protection.
Freeze it
Interesting article: Rubber
deterioration
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