UV resistance of plastic?

[journeyman Mick]

Just wondering if anyone out there knows about the UV resistance of different plastics. I just got a couple of 1000 litre pallet tanks which I will use for watering the garden. They have the triangular recycling symbol with the number "2" inside it. Underneath this are the letters "PE-HD". I know a guy down the road who's had one sitting in his yard for a few years, the zinc plated steel cage around it has gone fairly rusty but the plastic seems okay. I'm just wondering though if I need to paint it to stop the plastic breaking down in the sunlight as the UV up here is pretty intense.

Mick the water hoarder

[vsquizz]

Mick the fueltainers are pretty good for UV resistance but I don't know just how long they will last. They are sold as UV Stablized whatever that means. There must be a few around because I've sent lots your way over the last few years. New vessel delivery's so they can make the run from Darwin to TI or Cairns without going to Gove (Nhulunwhatever).


Cheers

[gemi_babe]

Each symbol in the Plastics Coding System consists of a number from 1 to 7 inside a chasing arrows triangle. The letters underneath the symbols are optional.

	Polyethylene terephalate (PET)		Polypropylene (PP)
	High density polyethylene (HDPE)		Polystyrene (PS) or Expandable polystyrene (EPS)
	Unplasticised polyvinyl chloride (UPVC) or Plasticised polyvinyl chloride (PPVC)		Other, including nylon and acrylic
	Low density polyethylene LDPE

These graphics are available from PACIA. EcoRecycle Victoria does not have copies of these graphics.


more info @ http://www.ecorecycle.vic.gov.au/www...asp?casid=2767

[gatiep]

HD PE would be a High Density Polyethylene plastic container.

Some applications of HDEP in the field of: A semicrystalline (typically 70-80%) whitish, semi-opaque commodity thermoplastic with properties similar to LDPE but which is significantly stronger and stiffer and has even better chemical resistance. Its impact resistance is reasonably high, and is retained at low temperatures, though that of LDPE is much higher. Its electrical properties, particularly at high frequencies, are very good but LDPE's are even better. Its barrier properties, though indifferent, are better than those of LDPE. Applications include a wide range of containers, blown bottles for food, pipe and pipe fittings and packaging film (LDPE =low density poly ethylene) Resistance to Ultra-violet is poor. So unless the HD PE is stabilized it will not last indefinately in strong sunlight. If the plastic is clear, transparent or a frosted clear I'll be positive that it is not stabilised. I know that the black plastic containers are mostly UV stabilised. The pigment is used to prevent breakdown of the plastic by UV.