UV stabilizer additives

q&a on a&m

UV stabilizer additives

Postby Len2 on Wed Mar 12, 2003 12:10 pm

It will help you to know a little bit about UV satbilizers, before you decide which type is best for your application.

Resin system and end-product environment are critical to the selection of a good stabilizer.

Some stabilizer are discribed as; absorbers, inhibitors, or even quenchers depending on what they do to inhibit damage to plastics by UV light.

Absorbers actually absorb incident UV light, dissipating the energy in a harmless manner. These stabililzers can remove radiation energy before it has a chance to harm the polymer, via energy transfer or through chemical reactions quenching the excited state of the irradiated molecule.

Some UV products shield the polymer by absorbing and/or scattering the in coming radiation. These latter types tend to stress the polymer due to their mode of activity. Carbon black for example will raise the temperature of a UV irradiated part because it is very good and absorbing the UV energe and urning it into heat energy.

Some are scavengers, they chemically react w/ oxidized or even peroxide type free radicals that are formed by the interaction between UV radiation and the polymer. No or fewer free radicals equals longer polymer life, better UV stability.

There is a little bit of information. Coming from me, it's got to be "a little" information. But...good news!

Please contact Ciba. Ask to speak to Technical service. Tell their technical people what resin systems you are trying to stabilize, the application or environment you're trying to fill, and if you can be willing to discuss other additive you are using in your formulations; fillers, pigments, lubricants. These all may have an effect on the selection. The better they understand your intended application and materials, the closer the stabilizer match.

Ciba can straighten it all out...just like BROWN!

Call: 1 -800-431-1900 Ask for technical service for polymer UV stabilizers.

Nice Bike!

Len:D



[This message has been edited by Len (Edited: 03/12/03).]
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UV stabilizer additives

Postby Platina on Mon Jul 21, 2003 12:01 pm

The answer to this question is quite clear! Nylons can be best stabilized by molecular modifiers to give not only UV stabilization to inhibit yellowing but also protect the colorants if present and physical properties. This new technology can be used at 0.10% to 0.30% and blow away conventional UV stabilizers from Ciba !!
Furthermore they can be purchased by MB from a company at 9367602311 called Celspan.
As for ABS thats tougher. Traditionally HALS and UVA are the best combinations with secondary antioxidants. In all cases the amounts needed are cost prohibitiive. Also if the ABS is pigmented all bets are off. Each colorant system requires its own type of stabilizer combination and level of concentration.
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Postby DwightDixon on Tue Dec 07, 2004 7:05 pm

Black is beautiful, best and cheapest, and can almost be universally used.
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Re: UV stabilizer additives

Postby akdeniz on Mon Sep 26, 2005 7:26 am

ALL kinds of Pvc additives

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Postby Len2 on Sat Oct 15, 2005 9:12 am

DwightDixon @ Dec 07 2004 06:05 wrote:Black is beautiful, best and cheapest, and can almost be universally used.


DD,
Black causes excessive heating in some parts, leading to early thermal failure.

We had to "buy back" a series of curbside trash receptacles from NYC, because they were crazing and breaking in the sunlight.  The best and cheapest UV absorber(carbon black, maybe not so beautiful) was used in these inferior parts.

THis became a very expensive buy back and replacement for us at a time when curbside collection was just beginning.  Not the time to stumble on a product intro, and we lost a lot of early sales to NY.

So watch what you think you are using for UV protection.  It can come back to haunt you.

Len :mrgreen:
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Re: UV stabilizer additives

Postby Skip on Sat Oct 15, 2005 2:11 pm

As I recall, carbon black is effective in ABS and polyolefins as a UV "stabilizer", while TiO2 (Rutile) is preferred in rigid PVC--as a UV "reflector". I'm thinking of extruded pipe, siding, profile products.

As to UV absorbers,they function well in clear polymer products, but in an opaque product UV degradation is strictly a surface phenomenon and only that UV absorber on the surface offers protection. If the UV- discolored and degraded surface is shaved away,material with original color and physicals are seen
below the surface. This is why capstock coextrusion with additive-rich material is done.
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Re: UV stabilizer additives

Postby Len2 on Sat Oct 22, 2005 12:00 pm

Skip @ Oct 15 2005 01:11 wrote:As I recall, carbon black is effective in ABS and polyolefins as a UV "stabilizer", while TiO2 (Rutile) is preferred in rigid PVC--as a UV "reflector". I'm thinking of extruded pipe, siding, profile products.

As to UV absorbers,they function well in clear polymer products, but in an opaque product UV degradation is strictly a surface phenomenon and only that UV absorber on the surface offers protection. If the UV- discolored and degraded surface is shaved away,material with original color and physicals are seen
below the surface. This is why capstock coextrusion with additive-rich material is done.


Surface, smurf-us!  Tell the folks at a famous maker of curbside containers that it's just a surface thing.  We had to replace (at cost) all the contaniers for NYC collection program, back in the day, and everyone of them were "protected" by CB from UV.  LOL.  The sun beat down, the temperature in the part rose, the free-radical cats and dogs were set loose...micro-crazing.  The micro-cracks in the "surface" caused the parts to fail upon minor impact.  Garbage collectors are not gentle w/ the empties, but no matter...the mode of failure was in adequate UV protection.

Just be cautious w/ a dependence on CB as an UVI.

Cap stocks work on the principle that the capping polymer are robust toward UV or that they have been properly stabilized against UVA, UVB, and IR radiation.  And yes UV degradation is a surface phenomenone.  Not many customers care to scrap off the caulky or yellowed polymer layer off their siding, lawn furnature, etc. to enjoy the prestine original color/strength of the article.

MTC - I stand by my original statements about carbon black as a UV inhibitor.  It can work, but testing in the end application/environment is recommended.


Len
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