Polyolefin composition containing optical brighteners having reduced migration

DETAILED DESCRIPTION We claim: 1.
A composition of matter comprising an inclusion compound of an optical brightener and a cyclodextrin selected from the class consisting of unsubstituted a, b, and g, cyclodextrin and a, b, and g, cyclodextrin having a substituent bonded to an oxygen atom in a glucose unit in said cyclodextrin, said substituent being selected from the class consisting of: a) alkyl radicals having 1 to 6 carbon atoms, b) radicals having the formula --(--CH--CH--R.
sup.
1 --O--).
sub.
n --H wherein R.
sup.
1 is selected from hydrogen and alkyl radicals having up to about six carbon atoms, and n is equal to a small whole number up to six, and c) radicals having the formula --CHR.
sup.
1 --CHOH--CHR.
sup.
1 -- wherein R.
sup.
1 has the same definition as above, such that said radicals bridge two cyclodextrin rings, and the number of said rings so bridged per molecule is from two to about six; said substituted cyclodextrin having not more than two substituents per glucose unit; said optical brightener having the formula ##STR3## wherein R.
sup.
1 and R.
sup.
2 are independently selected from hydrogen and alkyl radicals having up to about six carbon atoms.
2.
A composition of claim 1 wherein said cyclodextrin is selected from said unsubstituted and substituted .
beta.
cyclodextrin.
3.
A composition of claim 2 additionally containing a white pigment.
4.
A composition of claim 3 wherein said pigment is TiO.
sub.
2.




Description:
FIELD OF THE INVENTION This invention relates to an improved optical brightener.
More particularly, it relates to an inclusion compound having equimolar amounts of a fluorescent bis(benzoxazolyl) stilbene and a cyclodextrin.
The invention also relates to the use of such inclusion compounds as optical brighteners in photographic elements having a paper support.
BACKGROUND OF THE INVENTION A valuable class of photographic supports and elements comprises a paper base material having thereon a polyolefin coating Containing a white pigment and an optical brightener.
Such supports are particularly useful in the preparation of photographic elements such as color prints because they exhibit good brightness and excellent dimensional stability and are highly resistant to the action of aqueous acid and alkaline photographic processing solutions