Titanium dioxide and UV

This query was posted to OSG-L (AIC Objects Specialty Group) several
days ago, with no replies as yet.

I am seeking information from anyone on the list who may have
knowledge of clear coatings for application to exterior wood
surfaces that contain ultra fine TiO2 (1/10 the particle size of
"normal" pigmentary TiO2) as a UV blocking additive.

My understanding is that at this size, the TiO2 is smaller than the
wavelength of visible light.  The particles absorb, scatter and
reflect UV wavelengths.  These coatings would also typically contain
HALS.

The material is described at:

    <URL:http://www.paintandcoatings.com/content/productshowcase/
    product.asp?DocID={325806DA-B3EC-11D3-9A7B-00A0C9C83AFB}>

        **** Moderator's comments: The above URL has been wrapped
        for email. There should be no newline

Does anyone on the list have experience with commercial products
thus described?

D. Thor Minnick
Minnick Associates
Honolulu, Hawai'i


                                  ***
                  Conservation DistList Instance 15:25
                Distributed: Friday, September 21, 2001
                       Message Id: cdl-15-25-010
                                  ***