U.S. patent application number 08/961589 was filed with the patent office on 2001-07-12 for amide functional ultraviolet light absorbers for polyurethanes and polyureas.
Invention is credited to BURNS, DAVID M., LASCH, JAMES E., OLSON, DAVID B..
Application Number | 20010007885 08/961589 |
Document ID | / |
Family ID | 25504691 |
Filed Date | 2001-07-12 |
United States Patent
Application |
20010007885 |
Kind Code |
A1 |
LASCH, JAMES E. ; et
al. |
July 12, 2001 |
AMIDE FUNCTIONAL ULTRAVIOLET LIGHT ABSORBERS FOR POLYURETHANES AND
POLYUREAS
Abstract
An ultraviolet light absorbing material that resists blooming
and migration is made up of a polyurethane or polyurea polymer and
an amide functional ultraviolet light absorbing compound, wherein
the polymer and the amide functional ultraviolet light absorbing
compound are hydrogen bonded to one another. Polymeric films that
contain a polymeric matrix and the ultraviolet light absorbing
material are useful as the top layer in multilayer constructions
such as retroreflective sheetings and conformable marking
sheets.
Inventors: |
LASCH, JAMES E.; (OAKDALE,
MN) ; OLSON, DAVID B.; (ST. PAUL, MN) ; BURNS,
DAVID M.; (WOODBURY, MN) |
Correspondence
Address: |
ROBERT H JORDAN
3M OFFICE OF INTELLECTUAL PROPERTY
COUNSEL
P O BOX 33427
ST PAUL
MN
551333427
|
Family ID: |
25504691 |
Appl. No.: |
08/961589 |
Filed: |
October 31, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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08961589 |
Oct 31, 1997 |
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08642551 |
May 3, 1996 |
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5994431 |
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Current U.S.
Class: |
524/89 ; 430/160;
430/162; 524/91; 524/94; 525/128; 525/281; 525/343; 525/348;
525/375; 525/424; 525/452 |
Current CPC
Class: |
C08K 5/132 20130101;
C08L 75/02 20130101; C08L 75/02 20130101; C08K 5/132 20130101; C08K
5/3475 20130101; Y10S 430/132 20130101; C08K 5/132 20130101; C08L
75/04 20130101; C08K 5/3475 20130101; C08K 5/3475 20130101; C08K
5/20 20130101; C08K 5/20 20130101; C08L 75/04 20130101; C08L
2666/78 20130101; C08L 23/08 20130101; C08L 75/04 20130101; C08L
2666/78 20130101; C08L 23/08 20130101; C08L 23/08 20130101; C08L
75/04 20130101 |
Class at
Publication: |
524/89 ; 524/91;
524/94; 525/343; 525/348; 525/375; 525/281; 525/440; 525/452;
525/424; 525/128; 430/160; 430/162 |
International
Class: |
C08K 005/34 |
Claims
We claim:
1. An ultraviolet light absorbing material comprising at least one
of polyurethane or polyurea polymer and an amide functional
ultraviolet light absorbing compound, wherein the ultraviolet light
absorbing compound is hydrogen bonded to the said polyurethane or
polyurea and there is at least 1 hydrogen bonding site on the
polymer per mole of ultraviolet light absorbing compound.
2. The material of claim 1 wherein the polyurethane or polyurea
polymer comprises a polyurethane polymer.
3. The material of claim 1 wherein the polyurethane polymer
comprises aliphatic polyurethane.
4. The material of claim 1 wherein the amide functional ultraviolet
light absorbing compound is present in an amount of about 0.05 to
35 wt-% based on the total material weight.
5. The material of claim 1 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxyphenyl benzotriazole
moiety.
6. The material of claim 1 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (I): 10wherein R1
is straight-chain or branched C.sub.1-C.sub.18 alkyl,
straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S, or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, C.sub.1-C.sub.3 hydroxyalkyl or
11wherein R1' is H or straight-chain or branched C.sub.1-6-alkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R2 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-.sub.6 dialkylamino; each R3 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-6 alkyl,
straight-chain or branched C.sub.1-6 alkoxy, straight-chain or
branched C.sub.1-6 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, straight-chain or branched C.sub.1-6
dialkylamino, or aliphatic or aromatic substituted sulfoxide or
sulfone; m is 0 to 3; n is 0 to 4; p is 1 to 6; q is 1 or 2; and s
is 2 to 10.
7. The material of claim 1 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (II): 12wherein
R5 is straight-chain or branched C.sub.8 alkyl.
8. The material of claim 1 wherein R5 is n-octyl or
2-ethylhexyl.
9. The material of claim 1 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxybenzophenone
moiety.
10. The material of claim 1 wherein the amide functional
ultraviolet light absorbing compound is a compound of formula
(III): 13wherein each R8 is independently straight-chain or
branched C.sub.1-C.sub.18 alkyl, straight-chain or branched
C.sub.3-C.sub.18 alkyl which is interrupted by O, S or --NR10--,
C.sub.5-C.sub.12 cycloalkyl, C.sub.6-C.sub.14 aryl,
C.sub.7-C.sub.15 aralkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl; each R9
is independently a covalent bond, --O--, --S--, --CO--, or --
NR10--; R10 is H, straight-chain or branched C.sub.1-C.sub.18
alkyl, C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R6 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-18 alkyl, straight-chain or branched C.sub.1-18
alkoxy, straight-chain or branched C.sub.1-18 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino; each R7 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-18 alkyl,
straight-chain or branched C.sub.1-18 alkoxy, straight-chain or
branched C.sub.1-18 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, or straight-chain or branched C.sub.1-6
dialkylamino; u and v are independently 0 or 1, provided that
u+v=at least 1; x is 0 to 4; y is 0 to 5; and each z is
independently 1 to 6.
11. The material of claim 1 wherein the amide functional
ultraviolet light absorbing compound is a compound of formula (IV)
or (V): 14wherein R5 is a straight-chain or branched C.sub.8 alkyl
group.
12. The material of claim 1 wherein the amide functional
ultraviolet absorbing compound is a compound of formula (VI):
15wherein R11 is straight-chain or branched C.sub.1-C.sub.18 alkyl,
straight-chain or branched C.sub.3-C.sub.8 alkyl which is
interrupted by O, S or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R12 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino; each R13 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-6 alkyl,
straight-chain or branched C.sub.1-6 alkoxy, straight-chain or
branched C.sub.1-6 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, or straight-chain or branched C.sub.1-6
dialkylamino; a is 0 to 5; and b is 0 to 5.
13. A polymeric film comprising a polymeric matrix and an
ultraviolet light absorbing material, said ultraviolet light
absorbing material comprising at least one of a polyurethane and a
polyurea polymer and an amide functional ultraviolet light
absorbing compound, wherein the amide functional ultraviolet light
absorbing compound is hydrogen-bonded to the polyurethane or
polyurea polymer and there is at least 1 hydrogen bonding site on
the polymer per mole of ultraviolet light absorbing compound.
14. The film of claim 13 wherein the polymeric matrix comprises a
polyurethane polymer.
15. The film of claim 13 wherein the polymeric matrix comprises an
aliphatic polyurethane.
16. The film of claim 13 wherein the polymeric matrix comprises at
least one of a polyamide, polyacrylate, polycarbonate, polyester,
polyurethane, polyurea, polystyrene acrylonitrile, polyvinyl, and
olefin copolymer.
17. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound is present in an amount of about 0.05 to
8.0 wt-%, based on the total film weight.
18. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxyphenylbenzotriazole
moiety.
19. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (I): 16wherein R1
is straight-chain or branched C.sub.1-C.sub.18 alkyl,
straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.8-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, C.sub.1-C.sub.3 hydroxyalkyl or
17wherein R1' is H or straight-chain or branched C.sub.1-6 alkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R2 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino; each R3 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-6 alkyl,
straight-chain or branched C.sub.1-6 alkoxy, straight-chain or
branched C.sub.1-6 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, straight-chain or branched C.sub.1-6
dialkylamino, or aliphatic or aromatic substituted sulfoxide or
sulfone; m is 0 to 3; n is 0 to 4; p is 1 to 6; q is 1 or 2; and s
is 2 to 10.
20. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (II): 18wherein
R5 is a straight-chain or branched C.sub.8 alkyl group.
21. The film of claim 20 wherein R5 is n-octyl or 2-ethylhexyl.
22. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxybenzophenone
moiety.
23. The film of claim 13 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (VI): 19wherein
R11 is straight-chain or branched C.sub.1-C.sub.18 alkyl,
straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R12 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino; each R13 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-6 alkyl,
straight-chain or branched C.sub.1-6 alkoxy, straight-chain or
branched C.sub.1-6 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, or straight-chain or branched C.sub.1-6
dialkylamino; a is 0 to 5; and b is 0 to 5.
24. A method of protecting a substrate from the effects of
ultraviolet light, the method comprising applying a polymeric film
to the substrate, said film comprising a polymeric matrix and an
ultraviolet light absorbing material, said ultraviolet light
absorbing material comprising at least one of a polyurethane and a
polyurea polymer and an amide functional ultraviolet light
absorbing compound, wherein the ultraviolet light absorbing
compound is hydrogen bonded to the polyurethane or polyurea polymer
and there is at least one hydrogen bonding site on the polymer per
mole of ultraviolet light absorbing compound.
25. The method of claim 24 wherein the polymeric matrix comprises a
polyurethane polymer.
26. The method of claim 25 wherein the polymeric comprises an
aliphatic polyurethane polymer.
27. The method of claim 24 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxyphenylbenzotriazole
moiety.
28. The method of claim 24 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (II): 20wherein
R5 is a straight-chain or branched C.sub.8 alkyl group.
29. The method of claim 24 wherein the amide functional ultraviolet
light absorbing compound contains a 2-hydroxybenzophenone
moiety.
30. The method of claim 24 wherein the amide functional ultraviolet
light absorbing compound is a compound of formula (VI): 21wherein
R.sub.11 is straight-chain or branched C.sub.1-C.sub.18 alkyl,
straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl; each R12 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino; each R13 is independently
halogen, hydroxy, straight-chain or branched C.sub.1-6 alkyl,
straight-chain or branched C.sub.1-6 alkoxy, straight-chain or
branched C.sub.1-6 alkanol, amino, straight-chain or branched
C.sub.1-6 alkylamino, or straight-chain or branched C.sub.1-6
dialkylamino; a is 0 to 5; and b is 0 to 5.
31. The method of claim 24 wherein the amide functional ultraviolet
light absorbing compound contains a diphenylcyanoacrylamide or
diphenylcyanoacrylate group.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part to U.S.
application Ser. No. 08/642,551, filed May 3, 1996, which is
incorporated herein in its entirety by reference.
FIELD OF THE INVENTION
[0002] This invention relates to ultraviolet light absorbing
materials that comprise a polyurethane polymer or polyurea polymer
and an amide functional ultraviolet light absorbing compound. The
invention also relates to films that incorporate such ultraviolet
light absorbing materials and to articles that include such
films.
BACKGROUND OF THE INVENTION
[0003] The effect of ultraviolet light on articles such as
retroreflective sheetings for use on license plates or signage
articles that are exposed to the sun or other sources of
ultraviolet light are of great concern to the manufacturers of such
articles. Over time, constant or repeated exposure to ultraviolet
light can result in fading of the dyes and pigments used in such
articles and in the degradation or breakdown of the adhesives,
polymers, and other materials used in the construction of the
articles. This fading and degradation shortens the useful life of
the articles in question, making protection from ultraviolet light
exposure an issue of great importance to the manufacturers of such
articles.
[0004] Molecules that function as ultraviolet light absorbers are
generally known in the art. For example, in U.S. Pat. No. 4,853,471
Rody et al. describe 2-(2-hydroxyphenyl)-benzotriazole compounds
that are useful as ultraviolet light absorbers. These compounds are
described as useful in the stabilization of a wide variety of
polymeric materials against ultraviolet light, particularly those
that are used in the preparation of photographic materials. Other
classes of ultraviolet light absorbers include the
2-hydroxybenzophenones and the diphenylcyanoacrylates.
[0005] While such compounds are known to absorb ultraviolet light,
their incompatibility with the polyurethanes often used as the top
film in multilayer sheetings has limited their long term usefulness
in such constructions. The low solubility and/or high mobility of
typical ultraviolet light absorbers in polyurethanes results in an
inability to maintain high levels of these compounds in
polyurethane films; the compounds tend to bloom or migrate out of
the film, and the protective properties of the compounds are
lost.
[0006] Therefore, a need exists for ultraviolet light absorbing
materials that are compatible with and resist blooming out of
polyurethanes, and for products such as polyurethane films and
other articles that incorporate such a material.
SUMMARY OF THE INVENTION
[0007] The invention provides an ultraviolet light absorbing
material made up of a polyurethane or polyurea polymer and an amide
functional ultraviolet light absorbing compound, wherein the
ultraviolet light absorbing compound is hydrogen bonded to the
polyurethane or polyurea polymer and there is at least one hydrogen
bonding site on the polymer per mole of ultraviolet light absorbing
compound. For the sake of clarity, the invention will be described
with reference to polyurethane polymers (i.e., products of the
reaction of diisocyanates with diols) however it will be understood
that the invention includes polyurea polymers (i.e., products of
the reaction of diisocyanates with diamines).
[0008] The invention also provides a polymeric film made up of a
polymeric matrix and an ultraviolet light absorbing material, said
ultraviolet light absorbing material made up of a polyurethane
polymer and an amide functional ultraviolet light absorbing
compound, wherein the amide functional ultraviolet light absorbing
compound is hydrogen bonded to the polyurethane polymer and there
is at least one hydrogen bonding site on the polymer per mole of
ultraviolet light absorbing compound. By "polymeric matrix" is
meant a matrix comprising one or more homopolymers, copolymers,
polymer blends, or polymer alloys. The ultraviolet light absorbing
material is compatible with the polymeric matrix, i.e., it is
miscible therein or can be blended therein.
[0009] The invention further provides a method of protecting a
substrate from the effects of ultraviolet light, the method
comprising applying a polymeric film to the substrate, said film
comprising a polymeric matrix and an ultraviolet light absorbing
material, said ultraviolet light absorbing material comprising a
polyurethane polymer and an amide functional ultraviolet light
absorbing compound, wherein the ultraviolet light absorbing
compound is hydrogen bonded to the polyurethane polymer and there
is at least one hydrogen bonding site on the polymer per mole of
ultraviolet light absorbing compound.
[0010] In addition the invention provides products such as
retroreflective sheetings, signage articles and conformable marking
sheets that comprise the polymer films of the invention. In one
such aspect the invention provides a conformable marking sheet
comprising a top polymeric film layer having glass microspheres and
skid resistant particles partially embedded therein, the film
comprising a polymeric matrix and an ultraviolet light absorbing
material, the ultraviolet light absorbing material comprising a
polyurethane polymer and an amide functional light absorbing
compound, wherein the amide functional ultraviolet light absorbing
compound is hydrogen bonded to the polyurethane polymer and there
is at least one hydrogen bonding site on the polymer per mole of
ultraviolet light absorbing compound; an optional base layer, e.g.,
comprising a deformable thermoplastic polymer and a nonreinforcing
mineral particulate; an optional adhesive layer, e.g., pressure
sensitive adhesive; and an optional release liner.
[0011] In another aspect of the invention is provided an
enclosed-lens retroreflective sheeting, e.g., comprising a layer of
lenses anchored in a binder layer, a specularly reflective layer
underlying the lenses, and a top layer comprising a polymeric film,
said film comprising a polymeric matrix and an ultraviolet light
absorbing material, said ultraviolet light absorbing material
comprising a polyurethane polymer and an amide functional
ultraviolet light absorbing compound, wherein the amide functional
ultraviolet light absorbing compound is hydrogen-bonded to the
polyurethane polymer and there is at least 1 hydrogen bonding site
on the polymer per molecule of ultraviolet light absorbing
compound. Embedded-lens retroreflective sheetings and
encapsulated-lens retroreflective sheetings may be made in
accordance with the invention. Retroreflective signs and articles
including such sheetings are also provided.
[0012] In another aspect, the invention provides a cube corner type
retroreflective articles comprising an overlay or cover layer with
a layer of cube corner shaped elements on a side thereof wherein
the overlay or cover layer comprises a film comprising a polymeric
matrix and an ultraviolet light absorbing material, the ultraviolet
light absorbing material comprising a polyurethane polymer and an
amide functional light absorbing compound, wherein the amide
functional ultraviolet light absorbing compound is hydrogen bonded
to the polyurethane polymer and there is at least one hydrogen
bonding site on the polymer per mole of ultraviolet light absorbing
compound.
[0013] The term "polymer" is used herein to refer to compounds that
have more than one occurrence of a given monomeric structural
unit.
[0014] As used herein the term "amide functional ultraviolet light
absorbing compound" refers to a compound that absorbs ultraviolet
light and that contains at least one --CONH-- moiety. The term
"UVA" is used interchangeably with the term "amide functional
ultraviolet light absorbing compound".
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE
INVENTION
[0015] Ultraviolet Light Absorbing Material
[0016] As described above, the ultraviolet light absorbing material
of the invention is composed of an amide functional light absorbing
compound and a polyurethane polymer. In these materials there is at
least one hydrogen bonding site present on the polymer per mole of
ultraviolet light absorbing compound and the amide functional
ultraviolet light absorbing compound is hydrogen bonded to the
polyurethane polymer.
[0017] In addition to absorbing ultraviolet light, the UVAs useful
in the invention are preferably transparent to visible light.
Useful classes of amide functional ultraviolet light absorbing
compounds include amide containing 2-hydroxyphenylbenzotriazoles,
2-hydroxybenzophenones, diphenylcyanoacrylates, and triazines.
[0018] Any 2-hydroxyphenylbenzotriazole ultraviolet light absorbing
compound that contains an amide group may be used in the material
of the invention. Suitable 2-hydroxyphenylbenzotriazole compounds
include those having formula (I): 1
[0019] wherein R1 is straight-chain or branched C.sub.1-C.sub.18
alkyl, straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S, or --NR4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, C.sub.1-C.sub.3 hydroxyalkyl or
2
[0020] wherein R1' is H or straight-chain or branched C.sub.1-6
alkyl; R4 is H, straight-chain or branched C.sub.1-C18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl;
[0021] each R2 is independently halogen, hydroxy, straight-chain or
branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino;
[0022] each R3 is independently halogen, hydroxy, straight-chain or
branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, straight-chain or
branched C.sub.1-6 dialkylamino, or aliphatic or aromatic
substituted sulfoxide or sulfone 3
[0023] m is 0 to 3;
[0024] n is 0 to 4;
[0025] p is 1 to 6;
[0026] q is 1 or 2; and
[0027] s is 2 to 10.
[0028] Of these, 2-hydroxyphenylbenzotriazole compounds having
formula (II) are preferred: 4
[0029] wherein R5 is straight-chain or branched C.sub.8 alkyl.
[0030] Another useful class of ultraviolet light absorbing
compounds is the 2-hydroxybenzophenones. So long as they contain at
least one amide group, any of the 2-hydroxybenzophenone ultraviolet
light absorbing compounds may be used. Examples of
2-hydroxybenzophenone compounds that may be used in the invention
include those of formula (III): 5
[0031] wherein each R9 is independently a covalent bond, --O--,
--S--, --CO--, or --NR10--; each R8 is independently straight-chain
or branched C.sub.1-C.sub.18 alkyl, straight-chain or branched
C.sub.3-C.sub.18 alkyl which is interrupted by O, S or --NR10--,
C.sub.5-C.sub.12 cycloalkyl, C.sub.6-C.sub.14 aryl,
C.sub.7-C.sub.15 aralkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl; R10 is H,
straight-chain or branched C.sub.1-C.sub.18 alkyl, C.sub.6-C.sub.12
cycloalkyl, straight-chain or branched C.sub.3-C.sub.8 alkenyl,
C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18 aralkyl;
[0032] each R6 is independently halogen, hydroxy, straight-chain or
branched C.sub.1-18 alkyl, straight-chain or branched C.sub.1-18
alkoxy, straight-chain or branched C.sub.1-18 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino;
[0033] each R7 is independently halogen, hydroxy, straight-chain or
ranched C.sub.1-18 alkyl, straight-chain or branched C.sub.1-18
alkoxy, straight-chain or branched C.sub.1-18 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino;
[0034] u and v are independently 0 or 1, provided that u+v=at least
1;
[0035] x is 0 to 4;
[0036] y is 0 to 5; and
[0037] each z is independently 0 to 6.
[0038] 2-hydroxybenzophenone compounds of formula (III) may be
prepared by methods known in the art, such as by the reaction of an
acid of formula 6
[0039] with the corresponding amine.
[0040] Examples of particular 2-hydroxybenzophenone compounds
useful in the invention include compounds of formulas (IV) or (V):
7
[0041] wherein R5 is a straight-chain or branched C.sub.8 alkyl
group.
[0042] Diphenylcyanoacrylamide or diphenylcyanoacrylate ultraviolet
light absorbing compounds may also be used, so long as they contain
at least one amide group. Examples of useful
diphenylcyanoacrylamide compounds include those of formula (VI):
8
[0043] wherein R11 is straight-chain or branched C.sub.1-C.sub.18
alkyl, straight-chain or branched C.sub.3-C.sub.18 alkyl which is
interrupted by O, S or --NR.sub.4--, C.sub.5-C.sub.12 cycloalkyl,
C.sub.6-C.sub.14 aryl, C.sub.7-C.sub.15 aralkyl, straight-chain or
branched C.sub.3-C.sub.8 alkenyl, or C.sub.1-C.sub.3 hydroxyalkyl;
R4 is H, straight-chain or branched C.sub.1-C.sub.18 alkyl,
C.sub.6-C.sub.12 cycloalkyl, straight-chain or branched
C.sub.3-C.sub.8 alkenyl, C.sub.6-C.sub.14 aryl or C.sub.7-C.sub.18
aralkyl;
[0044] each R12 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino;
[0045] each R13 is independently halogen, hydroxy, straight-chain
or branched C.sub.1-6 alkyl, straight-chain or branched C.sub.1-6
alkoxy, straight-chain or branched C.sub.1-6 alkanol, amino,
straight-chain or branched C.sub.1-6 alkylamino, or straight-chain
or branched C.sub.1-6 dialkylamino;
[0046] a is 0 to 5; and
[0047] b is 0 to 5.
[0048] Dimers of any of these ultraviolet light absorbing compounds
can be used as well.
[0049] Other ultraviolet light absorbing compounds may also be
used, provided they contain at least one amide group. Examples of
such compounds include p-hydroxybenzoates, triazines and
diphenylcyanoacrylates. One or more amide functional ultraviolet
light absorbing compounds may be used alone or in combination in
the materials and films of the invention.
[0050] The amide functional ultraviolet light absorbing compound is
combined with a polyurethane polymer to produce the ultraviolet
light absorbing material of the invention. The polymer contains at
least one monomer having a 9
[0051] group. At least one such hydrogen bonding site should be
present per molecule of amide functional ultraviolet light
absorbing compound to allow for adequate formation of hydrogen
bonds between the polyurethane polymer and the amide functional
ultraviolet light absorbing compound.
[0052] The polyurethane polymer is prepared using polymerization
methods known in the art. Detailed information on polymer
preparation may be found, for example, in the Encyclopedia of
Polymer Science and Engineering, Vol. 6, Wiley & Sons 1986.
[0053] Many polyurethane polymers may be used in this invention.
Illustrative examples include those prepared from diisocyanates,
diol chain extenders, and polyols, e.g., H.sub.12MDI available from
Bayer Corp. as DESMODUR.TM. W, butane diol chain extender, and
polycaprolactone having a weight average molecular weight of about
2000 terminated with hydroxyl groups. The diisocyanate and butane
diol are considered to form "hard segments" with the
polycaprolactone as the "soft segments". Typically the hard segment
may comprise about 45 weight percent of the total. The use of other
diisocyanates is well known but aliphatic diisocyanates are
typically preferred because they offer better resistance to
yellowing than do aromatic diisocyanates. A wide range of diols and
polyols known to those skilled in the art may be used to prepare
suitable polyurethanes.
[0054] For some applications, it will be preferred to use aliphatic
thermoplastic melt-extrudable polyurethanes.
[0055] In addition to the polyurethane polymer and the amide
functional ultraviolet light absorbing compound, other components
may be present in the ultraviolet light absorbing material of the
invention. Examples of such additives include waxes, lubricants,
antioxidants, preservatives, plasticizers, dyes, pigments, hindered
amine light stabilizers (HALS), other stabilizers, and the like.
The exact type and amount of additive used will vary according to
the type of UVA and polymer used and their relative proportions,
the intended final use of the material, and other factors known to
those of skill in the art.
[0056] The ultraviolet light absorbing material of the invention is
prepared by combining the polyurethane polymer with the amide
functional ultraviolet light absorbing compound. A sufficient
amount of the UVA is present to provide good ultraviolet light
absorbance without blooming or leaching out of the material. In
general, about 0.05 to 35 wt-%, preferably about 0.05 to 5 wt-%,
and most preferably about 0.25 to 2.5 wt-% of the amide functional
ultraviolet light absorbing compound is present in the material,
based on the total material weight.
[0057] The ultraviolet light absorbing material may be prepared by
combining the amide functional ultraviolet light absorbing compound
and the polyurethane polymer so that hydrogen bonding takes place
between them. This may be accomplished by a number of different
methods, including melt blending. The polymer and the UVA may also
be compounded in an extruder. The presence of hydrogen bonds
between the polyurethane polymer and the amide functional
ultraviolet light absorbing compound may be verified by using
analytical methods known in the art, such as by a shift in the IR
spectrum of the material. See, for example, March, Advanced Organic
Chemistry, pp.71-3 3d Ed., John Wiley and Sons (1985) and Symons,
Chem. Soc. Rev. 12, pp.1-34 (1983).
[0058] The material thus formed may be used directly by forming
into a film, or may be blended into other polymers which are then
formed into films stabilized against the effects of ultraviolet
light.
[0059] Polymeric Film
[0060] The polymeric film of the invention is made up of the
ultraviolet light absorbing material of the invention in
combination with a polymeric matrix. The ultraviolet light
absorbing material preferably resists blooming and/or migration out
of the polymeric matrix, thereby increasing the useful life of
articles that are protected by the film, which is used as a top
layer.
[0061] As described above, the ultraviolet light absorbing material
is compatible with the polymeric matrix. Any suitable polymeric
matrix can be used in accordance with the invention, dependent in
part upon the final application or product which is desired.
Illustrative examples of polymeric matrices in which ultraviolet
light absorbing materials may be incorporated in accordance with
the invention include polyamides, polyacrylates, polycarbonates,
polyesters, polyurethanes and polyureas (the same or different than
the polyurethane(s) or polyurea(s) to which the ultraviolet light
absorbing compound is hydrogen bonded), poly(styrene
co-acrylonitriles), polyvinyls, olefin copolymers, and the
like.
[0062] The polymeric film is prepared by combining the ultraviolet
light absorbing material of the invention with a polymeric matrix.
The ultraviolet light absorbing material is generally present in an
amount high enough to provide the resultant polymeric matrix with
the ability to absorb ultraviolet light but not so high that the
material migrates, separates, or blooms out of the matrix.
Typically the polymeric film contains about 0.05 to 35 wt-%,
preferably about 0.25 to 8 wt-% of the ultraviolet light absorbing
compound, based on the total weight of the film.
[0063] The polymeric film may be prepared by blending a melt of the
matrix polymer with a melt of the ultraviolet light absorbing
material with stirring continued until the mixture is uniform.
After uniformity is achieved, the mixture may be pressed or formed
into a film using methods known in the art. The film may also be
prepared by co-extruding the matrix polymer and the ultraviolet
light absorbing material directly into the desired film.
[0064] Retroreflective Sheetings
[0065] The polymeric films of the invention may be used as the top
layer or cover film of a multilayered retroreflective sheeting.
Retroreflective sheetings are generally known in the art, as seen
for example in Bailey et al., U.S. Pat. No. 4,767,659, which is
incorporated herein by reference in its entirety. Polymeric films
of the invention may be used as cover films or overlays for
embedded-lens and encapsulated-lens sheetings (both
microsphere-based and cube corner type); protecting underlying
layers of retroreflective elements, binder layers, etc. U.S. Pat.
No. 5,450,235 (Smith et al.) and U.S. application Ser. No.
08/472,444 (Docket No. 48924USA4D), filed Jun. 7, 1995,
incorporated herein by reference in their entirety, disclose
flexible cube corner type retroreflective sheetings in which
polymeric films of the invention may be used. The polymeric films
provide protection to the lower layers of the sheeting from
ultraviolet light, thereby extending the useful life of the
sheeting and articles that incorporate the sheeting.
[0066] In addition to providing protection from ultraviolet light,
when used as the top layer of a retroreflective sheeting, the
polymeric film in some instances should additionally be
sufficiently extensible to withstand substantial stretching such as
the embossing of a license plate, sufficiently soft that it resists
localized delamination when stretched to conform to an irregular
surface, and should have good impact resistance. Preferably, when
used as the top layer of a retroreflective sheeting the polymeric
film has an elongation of at least about 100%, good impact
resistance, toughness, and transparency.
[0067] Retroreflective sheetings that have the polymeric film of
the invention as a top layer typically contain multiple layers. One
example of a suitable retroreflective sheeting is a sheeting
article that may contain a binder layer; a layer of glass
microspheres fully or partially embedded in the binder layer; a
specularly reflective layer; and an adhesive layer covered by a
removable liner. Other layers may be present as desired. Other
types of retroreflective elements can be used if desired.
[0068] To prepare a retroreflective sheeting using the polymeric
film of the invention, the film is laminated to a retroreflecting
base material that contains multiple layers as described above.
[0069] The retroreflective sheetings prepared using the polymeric
film of the invention may be applied to a wide variety of articles,
including traffic signs, rollup signs, sheetings used on canvas
backings, barriers, and cones, as well as embossed license or
information plates. The preparation of embossed information plates
is described in U.S. Pat. Nos. 5,085,918 and 5,227,194, both of
which are incorporated herein by reference in their entirety.
[0070] Conformable Marking Sheets
[0071] Polymeric films of the invention may also be used in the
preparation of conformable pavement marking sheets. Illustrative
examples of such conformable marking sheets are described in Lasch
et al., U.S. Pat. No. 5,194,113, which is incorporated herein by
reference in its entirety.
[0072] When used in the preparation of a conformable marking sheet,
the polymeric film should be sufficiently ductile to allow the
sheet to conform to the surface of the pavement or other substrate
in order to improve the adhesion of the sheet to the substrate.
When used as a top layer in a conformable marking sheet, the
polymeric film preferably includes a visibility enhancing pigment
such as titanium dioxide or lead chromate.
[0073] The polymeric film top sheet or layer may be extruded or
laminated directly onto the other layers of the conformable sheet,
or an adhesive or other layer may be interposed between the top
layer and other layers of the sheet.
[0074] Polymeric films of the invention may also be used as a
marking sheet independent of a conforming layer. If used in this
manner, the polymeric film may be laminated to a layer of pressure
sensitive or other suitable adhesive to improve adhesion to the
pavement or other substrate. A release liner may also be present to
provide ease of handling and storage. In addition, particles may be
fully or partially embedded in the top surface of the film to
improve the retroreflectivity and/or skid resistance properties of
the film.
* * * * *