Robert is right on. Carbon black is degraded about as far as it's going to
go, so sunlight won't affect it. When you load up a polymer with it, the UV
can't penetrate past the first few molecular layers to break apart the
polymers. It's the cheapest and most effective UV stabilizer there is. The
guy that was talking about heat may have been thinking about thin films, say
in the 2-4 mil range (0.002 - 0.004") but that doesn't apply to ropes. I
used to work with a lot of this stuff, and the hardest thing to stabilize
are these clear films as used in greenhouses, etc. There are two types of
stabilizers besides pigments... nickel compounds and benzophenones, the
former being better. Nickel compounds give clear film a greenish tint.
Anyway, I use nothing but black braided for my normal docklines, but do have
some long throwing lines made up with 4' eyes of white three strand per CC's
recommendations. They only get temporary use when we're out cruising though.
PS: Polypropylene won't last in the sun, so those yellow floating lines need
to be kept out of the sun or replaced often.
Keith
All I ask is a chance to prove that money can't make me happy.
----- Original Message -----
From: "Robert Kassal" bkboater@worldnet.att.net
The plastics industry has two main methods to improve UV resistance of a
given
plastic, and yes, nylon and polyester are plastics. One method is to add a
significant amount of carbon black, the other is to add UV absorbers. The
carbon black may well cause more heating as was suggested, but it provides
the
UV resistance by absorbing the UV rays at the surface thereby reducing the
amount they penetrate the plastic. Some pigments may actually increase UV
degradation through secondary chemical effects. I don't have first hand
information of the UV stabilization technology that is used in the fiber
industry.
Robert is right on. Carbon black is degraded about as far as it's going to
go, so sunlight won't affect it. When you load up a polymer with it, the UV
can't penetrate past the first few molecular layers to break apart the
polymers. It's the cheapest and most effective UV stabilizer there is. The
guy that was talking about heat may have been thinking about thin films, say
in the 2-4 mil range (0.002 - 0.004") but that doesn't apply to ropes. I
used to work with a lot of this stuff, and the hardest thing to stabilize
are these clear films as used in greenhouses, etc. There are two types of
stabilizers besides pigments... nickel compounds and benzophenones, the
former being better. Nickel compounds give clear film a greenish tint.
Anyway, I use nothing but black braided for my normal docklines, but do have
some long throwing lines made up with 4' eyes of white three strand per CC's
recommendations. They only get temporary use when we're out cruising though.
PS: Polypropylene won't last in the sun, so those yellow floating lines need
to be kept out of the sun or replaced often.
Keith
_____
All I ask is a chance to prove that money can't make me happy.
----- Original Message -----
From: "Robert Kassal" <bkboater@worldnet.att.net>
> The plastics industry has two main methods to improve UV resistance of a
> given
> plastic, and yes, nylon and polyester are plastics. One method is to add a
> significant amount of carbon black, the other is to add UV absorbers. The
> carbon black may well cause more heating as was suggested, but it provides
> the
> UV resistance by absorbing the UV rays at the surface thereby reducing the
> amount they penetrate the plastic. Some pigments may actually increase UV
> degradation through secondary chemical effects. I don't have first hand
> information of the UV stabilization technology that is used in the fiber
> industry.
