Note: Descriptions are shown in the official language in which they were submitted.
W094/00524 ~1 3 8 2 8 ~ PCT/~S93/05938
W-ABSORBING POLYMER LATEX
Disclosed herein are aqueous latices of W -
absorbing polymer adapted to forming laminate coatings
of visible light transparent, coherent polymeric film
and methods of making and using such latices and
laminates.
BACKGROUND OF THE I~v~ ON
Japanese Kokai 57-45169 and 58-38269
disclose solvent polymerization of copolymers
containing W-absorbing monomer units useful as
coating additives. Specifically disclosed copolymers
comprise up to about 22 mole percent (about 30 weight
percent) benzotriazole W-absorbing monomer units an a
non- W -absorbing comonomer such as methyl methacry-
late, styrene or butyl acrylate.
U.S. Patent 4,528,311 discloses opticallyclear W -absorbing copolymers comprising up to 20
weight percent of 2-hydroxy-5-acrylyloxyphenyl-2H-
benzotriazoles for W -absorbing films that afford 85%
absorption at 400 nanometers and 1 millimeter
thickness.
U.S. Patent 4,576,870 discloses coextruded
laminates comprising W-absorbing polymer coatings
(10-100 microns thick) comprising up to 20 weight
percent of 2-hydroxyphenylbenzotriazole monomers.
U.S. Patents 4,785,063 and 4,892,915
disclose incorporation of 2-(2-hydroxy-5-acryloyl-
oxyalkyl)-phenyl-2H-benzotriazoles W -absorbing
copolymerizable additives at low levels, e.g. at about
2 percent, in acrylate coatings which are cured by E-
beam radiation.
U.S. Patent 4,927,891 discloses acrylic
coating resins with up to 20 weight percent hydrazide
functionalized light stabilizers, e.g. hindered amine
light stabilizers, 2-hydroxybenzophenones, 2-(2-
hydroxyphenyl)-2H-benzotriazoles, aryl salicylates and
oxalanilides.
W094/00524 ~ PCT~US93/05938 ~
21~8283 -2-
EPO o 282 294 discloses optically clear
silicone polymers containing vinylsilylalkoxy arylben-
zotriazole monomer units.
U.S. Patents 3,745,010 and 3,761,272
disclose emulsion polymerized, W -absorbing benzotria-
zole acrylate copolymers useful in photographic appli-
cations, e.g. to protect photographic film against W
radiation. Copolymers, e.g. of methylmethacrylate or
butylacrylate and 2-70% benzotriazole-functionalized
methacrylates, are useful at up to 40% by weight in
UV-absorbing layers. For instance, glass coated with
gelatin and emulsions of such W-absorbing copolymers
provided photographic filters having a maximum absorp-
tion at 352 nm.
U.S. Patents 4,612,358 and 4,652,656
disclose W -absorbing copolymers of 20-60 percent
benzotriazole-~unctionalized acrylamides use~ul ~or
protective layers for W sensitive plastics. Bulk
polymerized copolymers comprised methyl methacrylate
and 20 weight percent benzotriazole monomer. Emulsion
polymerized copolymers comprising methylmethacrylate
and 50 weight percent benzotriazole monomer were
prepared in large particle size (100 micron). Such
UV-absorbing copolymers are said to be useful for
providing a W protective layer for a W sensitive
plastic.
U.S. Patents 4,443,534 and 4,455,368
disclose W -absorbing copolymer latex useful in W-
absorbing protective layers for photographic film,
e.g. light sensitive silver halide material.
SUMMARY OF THE lN V ~:N'l'lON
This invention provides aqueous latices
adapted to forming visible light-transparent, coherent
polymeric films, e.g. in laminates, as protective
coatings or as adhesives. The latices comprise
colloidal particles of a UV-absorbing polymer
suspended in a substantially a~ueous medium,
~ W 0 94/00524 2 1 3 8 2 8 3 PC~r/US93/05938
3-
wherein said particles are less than 5 micrometers in
diameter. Useful W-absorbing polymer include
homopolymers and copolymers of vinyl-functionalized
monomer of benzotriazole or benzophenone and mixtures
with plasticizer and/or coalescing agent. Plasticizer
and coalescing agents are useful for providing polymer
with reduced glass transition temperature (Tg) to
facilitate coalescence of polymer particles into
coherent films. Useful additives for the latices of
this invention include wetting agents, surfactants,
and crosslinking agents, anti-oxidants and radical
scavengers.
The latices of this invention are
particularly useful in providing clear, thin coatings
on W -susceptible substrates; such coatings can be
applied as topcoats, as intermediate layers in a
laminate or as adhesive layers. The specific
application of the W -absorbing polymer coating will
depend on the intended use of the substrate, e.g. as a
coating to protect outdoor articles such as tents,
labels, posters and signs, as a W barrier on glass or
plastic windows, display cases and containers, as an
intermediate or top coat on flooring; as an adhesive
to apply decals or transparent films to transparent
substrates, or as a compounding additive for colorfast
inks.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 and 2 illustrate the efficacy of
films of copolymers of this invention in abating
transmission of W radiation.
Figures 3A and 3B illustrate the efficacy of
a copolymer of this invention in abating transmission
of W radiation from fluorescent lamps.
DETATT~n DESCRIPTION OF PREFERRED EMBODIMENTS
The aqueous latices of this invention are
adapted to forming visible light-transparent, coherent
polymeric films, e.g. in laminates, as protective
coatings or as adhesives. The latices comprise
a 2 8 3 PCT/US93/05938 -
--4--
colloidal particles of a W-absorbing polymer
suspended in a substantially aqueous medium, i.e. the
medium is primarily water with minor amounts of
organic adjuvants which may be useful in providing
enhanced coating properties or solubility to
additives. The W -absorbing polymers of this
invention include homopolymers of vinyl-functionalized
W -absorbing monomer of benzotriazole or benzophenone,
e.g. an acrylate or methacrylate functionalized
benzotriazole or benzophenone such as 2-(2'-hydroxy-5-
methacrylyloxyethylphenyl)-2H-benzotriazole, 2-(2'-
hydroxy-3-tertbutyl-5-(methacrylyloxyethyl)phenyl
propionate)-2H-benzotriazole and 2-hydroxy-4-acrylyl
oxyethoxy benzophenone. Preferred W -absorbing
polymers useful in this invention are copolymers of at
least 20 weight percent of vinyl-functionalized
monomer of benzotriazole or benzophenone and up to 80
percent by weight of one or more other vinyl monomers.
More pre~erably, the W-absorbing copolymers of this
invention comprise at least 3 0 weight percent vinyl-
functionalized W -absorbing monomer~ even more
preferably at least 40 weight percent and not more
than 80 weight percent of W-absorbing monomer, say
between 45 and 75 weight percent.
Other vinyl monomers useful in the
copolymers of this invention include acrylic acid and
esters thereof such as ethyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, hydroxyethyl acrylate,
hydroxypropyl acrylate and carboxyethylacrylate;
methacrylic acid and esters thereof such as methyl-
methacrylate, ethyl methacrylate, butyl methacrylate,
2-ethylhexyl methacrylate and decylmethacrylate;
hydroxyvinyl compounds such as hydroxyethyl
methacrylate, hydroxypropyl methacrylate and
hydroxyethylacrylate; vinyl aromatics such as styrene;
cyano compounds such as acrylonitrile and acrylamide;
vinyl acids such a maleic acid, maleic anhydride or
acrylic acid; vinyl esters such as vinyl acetate,
2I~8283
W094/00524 PCT/US93/05938
_5_
vinyl formal and vinyl butyral; crosslinking monomers
such as glycidyl methacrylate, allyl methacrylate,
diallyl maleate and butylene dicarylate; and mixtures
thereof. Preferred other vinyl monomers include
predominately acrylates and methacrylates. The
selection of the non-W -absorbing comonomers will
generally be made depending on application performance
criteria, such as desired Tg, adhesiveness,
compatibility with other materials in a laminate,
toughness, flexibility, etc. A mixture of non-W -
absorbing monomers can be useful, e.g.
methylmethacrylate can provide high Tg and
hydroxyethyl acrylate can provide enhanced adhesion.
The use of aqueous latices for providing W-
absorbing films provides an environmental advantage,
e.g. the avoidance of volatile organic solvents. Such
latices can be prepared by emulsion polymerization of
the monomer units using well known t~chn; ques using
surfactants and modifiers such as acrylic acid,
carboxyethylacrylate and hydroxyethylmethacrylate.
Useful surfactants include non-ionic alkaryl polyether
alcohols and anionic alkaryl polyether sulfonates.
Mixtures of surfactant dispersed vinyl monomers can be
polymerized by the action of a radical initiator, e.g.
potassium persulfate. Those skilled in the art of
emulsion polymerization can readily prepare colloidal
latices of the polymers of this invention in desirable
particle size diameter, e.g. less than 5 micrometers,
more preferably less than 1 micrometer, even more
preferably between O.O5 and 0.5 micrometers. Small
particle size of colloidal polymer facilitates the
preparations of desirable thin films, e.g. less than
25 micrometers, preferably on the order of 1 to 5
micrometers.
The polymers of this invention can have a Tg
in the range of -50 C to 150 C dep~n~in~ on the
desired application. For applications that are
exposed to high temperature, preferred coatings of
W094/00524 PCT/US93/05938 ~
213~283 -6-
- W -absorbing copolymers have a Tg greater than 20 C,
preferably at least 50 C or higher. Higher Tg
copolymers can be prepared by selecting appropriate
comonomers, e.g. higher levels of monomers such as
methylmethacrylate, styrene or acrylonitrile and lower
levels of monomers such as butyl acrylate. When high
Tg copolymers are applied as coatings from aqueous
latices, heat treatment may be necessary to achieve
sufficient coalescence of polymer particles to effect
a coherent, uniform, smooth coating. Alternatively,
high Tg copolymer coatings can be achieved by
providing a latex of a crosslinkable polymer, e.g. a
copolymer with crosslinking monomer units. Cross-
linking monomer units can comprise a variety of
pendant groups, e.g. vinyl, acid, hydroxyl, epoxy or
isocyante groups or mixtures thereof. For instance,
W -absorbing copolymer comprising small amounts of
vinyl alcohol and glycidyl methacrylate monomer units
can readily self polymerize to provide a crosslinked
film. Adjunct crosslinking agents can be also
lncorporated lnto the d Isperced polymer or be
independently dispersed in the aqueous medium.
Dep~n~;ng on the crosslinkable pendant groups in the
W -absorbing copolymer, adjunct crosslinking agents
can comprise metal driers such as ammonium
zirconylcarbonate, calcium acetate, zinc oxide, drying
oils such as surfactant-stabilized unsaturated fatty
acids, polyepoxy or polyvinyl compounds or mixtures
thereof, urea-formaldhyde compounds such as methylated
urea-formaldehyde resin or melamine-formaldehyde
compounds such as methylated melamine-formaldehyde
resin. A stablized W-absorbing copolymer film can be
also be achieved by blending a latex of the W -
absorbing copolymer with a latex of a crosslinked
network-forming resin such as an alkyd resin. Cross-
linking can promote high Tg, toughness, solvent
resistance. Thus, preferred latices which are more
amenable to coating applications comprise suspended
W O 94/00524 2 1 3 ~ 2 8 3 PC~r/US93/05938
--7-- .
polymer having a Tg lower than the Tg desired for the
polymer coating application. Such latices comprise
copolymer having a Tg greater than O C, preferably
greater than 20 C.
For many applications desirable W -absorbing
films can be achieved using polymers that are enhanced
with plasticizer and/or coalescing agents which can
reduce the Tg of the polymer to facilitate film
formation at lower temperatures. Useful coalescing
agents comprise volatile solvent for said polymer
added in an amount sufficient to swell the polymer and
thereby reduce the Tg of the polymer in the latex to
less than 50 C, preferably to less than 30 C. Upon
drying and film formation the volatile coalescing
agent should be expelled from the polymer providing a
film with a substantially increased Tg as compared to
the Tg of the latex-dispersed polymer. Useful latices
of this invention comprising otherwise high Tg polymer
can comprise up to 20 percent by weight of a volatile
solvent as a coalescing agent. Among the useful
volatile solvents are fast evaporating solvents such
as acetone, ethyl acetate, methyl ethyl ketone,
isopropyl acetate, isopropyl ether and tetrahydro-
furan; medium evaporating solvents such as isobutyl
acetate, n-butyl acetate, sec-butyl acetate, sec-butyl
alcohol, tert-butyl alcohol, diethyl ketone, ethyl
alcohol, methyl alcohol, methyl isobutyl ketone,
methyl isopropyl ketone, methyl n-propyl ketone,
2-nitropropane, n-propyl acetate, isopropyl alcohol
and n-propyl alcohol; and slow evaporating solvents
such as amyl acetate, tert-amyl alcohol, isobutyl
alcohol, n-butyl alcohol, diethylene glycol monobutyl
ether, ethylene glycol monobutyl ether, m-cresol,
cyclohexanol, cyclohexanone, diacetone alcohol,
diethylene glycol, diethylene glycol monobutyl ether
acetate, diisobutyl ketone, dimethyl formamide,
diethylene glycol monoethyl ether, dipropylene glycol
monomethyl ether, dipropylene glycol monomethyl ether
W094/00s24 ` PCT/US93/05938
2~3~2~3 -8-
- acetate, ethyl butyl ketone, ethyl 3-ethoxypropionate,
ethylene glycol, 2 ethylhexanol, 2 ethylhexyl acetate,
ethylene glycol monoethyl ether acetate, hexylene
glycol, isobutyl isobutyrate, isophorone, methyl
n-amyl ketone, diethylene glycol monomethyl ether,
methyl isoamyl ketone, methyl isobutyl carbinol,
ethylene glycol monomethyl ether, N-methyl-2-
pyrrolidone, ethylene glycol monoethyl ether,
propylene glycol, propylene glycol monomethyl ether,
propylene glycol monomethyl ether acetate, propylene
glycol mono tertiary butyl ether and triethylene
glycol. Especially preferred coalescing agents are
selected from the group consisting of diethylene
glycol monoethyl ether, dipropylene glycol monomethyl
ether, tripropylene glycol monomethyl ether,
diethylene glycol monobutyl ether, ethylene glycol
monobutyl ether, propylene glycol monobutyl ether and
N--methyl--2--pyrrol idone .
In many cases it is advantageous to
incorporate plasticizer into the polymer of this
inventlon, e.g. to lower the temperature soft~n; ng
range of polymers to facilitate coalescence at
preferably lower temperatures. Plasticizer can also
impart other desirable properties to films made from
the polymers having a high level of W -absorbing
monomer. Properties imparted by plasticizer include
flexibility, toughness, flame retardance, low
temperature flexibility and improved adhesion. The
type and amount of plasticizer can be selected by
those skilled in the acrylic polymer compolln~;ng art,
regardless of whether a polymer of this invention is
applied as a soft adhesive film, a tough thermoplastic
film or a crosslinked thermosetting film. Plasticizer
can be added to the polymer during emulsion polymeri-
zation. Plasticizer can also be incorporated byintimately mixing dispersed plasticizer with dispersed
polymer. Useful plasticizer can include alkyl adipate
esters such as dioctyl adipate, alkyl aryl adipate
~ W094/00524 2 1 3 8 2 8~ PCT/US93/OS938
esters such as benzyl octyl adipate, benzoate esters
such as diethylene glycol dibenzoate, alkyl phthalate
esters such as di-2-ethylhexyl phthalate and mixed
alkyl phthalate esters such as heptyl nonyl undecyl
phthalate, aryl phthalate esters such as diphenyl
phthalate, alkyl aryl phthalate esters such as butyl
benzyl phthalate, alkyl citrate esters such as
triethyl citrate and aryl phosphate esters such as
triphenyl phosphate. Preferred plasticizers for
acrylic polymers of this invention include alkyl aryl
phosphate esters such as 2-ethylhexyl diphenyl
phosphate and isodecyl diphenyl phosphate which
provide desired clarity, low temperature flexibility
and fire retardance. When adhesive polymers are
desired a plasticizer such as butyl benzyl phthalate
is useful. In many cases it may be useful to
incorporate both coalescing agent and plasticizer into
the latex-dispersed polymer of this invention.
The latices of this invention can be
enhanced by a variety of other common coating
additives, e.g. thickening agents, wetting agents,
anti-oxidants such as hindered phenols, radical
scavengers such as hindered amines, slip and mar
agents such as silicones, biocides, fire retardants
and even pigments or dyes.
The latices of this invention typically
comprise less than 1 percent by weight of a water
soluble thickening agent including natural gums such
as alginates, cellulosics such as methylcellulose,
carboxymethylcellulose and hydroxypropyl methylcellu-
lose, polyacrylic acids and salts thereof, and water
soluble polyuretane thickeners such as non-ionic
polyethylene oxide urethane block copolymers; a
variety of useful thicken;ng agents is available from
Rohm and Haas Company. More typically the amount of
thickening agent is determined by routine
experimentation to provide the latex with a viscosity
at 25 C greater than 40 centipoises, preferably
~ 1 3~ ~3 PCT/US93/05938 ~
--10--
greater than lO0 centipoises, more preferably greater
than 200 centipoises or higher, e.g. greater than 300
centipoises. Such latex viscosity can be readily
determined using common apparatus such as Brookfield
viscometer using a No. 1 spindle rotating in the latex
at 5 rpm.
The ability of a latex to effectively coat a
substrate depends in large degree on the relative
values of surface tension of the latex and the
substrate surface. In the case of polymer substrates,
surface tension varies by polymer species and with
temperature, e.g. surface tension typically decreases
with increasing temperature. For example, the surface
tension at 25 ~C is about 45 dynes/cm2 for polyethylene
terephthalate, about 43 for polycarbonate, about 43
for styrene-acrylonitrile copolymer (33 mole %
acrylonitrile), about 42 for polyvinyl chloride, about
38 for polyvinyl butyral, about 35 for branched
polyethylene, abo~t 30 for polypropylene and abou~ 24
for polytetrafluoro-ethylene. Reference is made to
the "Polymer Handbook", Third Edition, edited J.
Brandrup & E.H. Immergut, published by John Wiley &
Sons, Inc. 1989, pages VI/411-434 for a more detailed
tabulation of surface tension for polymers.
Polymer latex prepared with a ~jn;r~l amount
of surfactant to maintain a colloidal suspension of
polymer may have a surface tension in the range of 45
to 50 dynes/cm2. The surface tension of polymer
latices of this invention can be modified to more
nearly coincide with the surface tension of a
substrate to be coated by addition of up to about 10
percent by weight of water soluble wetting agent which
can be volatile, e.g. lower aliphatic alcohols, or
non-volatile, e.g. non-ionic surfactants or anionic
surfactants. Useful lower aliphatic alcohols include
ethanol, n-propanol, isopropanol, n-butanol, iso-
butanol, n-pentanol, n-hexanol and cyclohexanol.
Preferred alcohol wetting agents are the C3 and C4
~ W 0 94/00524 2138283 PC~r/US93/05938
alkyl alcohol, e.g. n-propanol or n-butanol. Among
the wide variety of useful commercial nonionic
surfactants are the alkaryl polyether alcohols such as
octylphenol (ethylene oxide)n alcohols, where n=1,70.
available as the Triton X-series of non-ionic
surfactants available from Union Carbide Corporation.
Among the wide variety of useful commercial anionic
surfactants are the alkaryl polyether sulfonates,
sulfosuccinates, alkyl naphthalene sulfonates and
alkyl polyoxy carboxylates. Thus, in one aspect of
this invention, a preferred latex has sufficient
wetting agent to provide a surface tension of less
than 43 dynes/cm2, more preferably less than 41
dynes/cm2.
A preferred aspect of this invention
provides latex of W -absorbing copolymers comprising
sufficient wetting, thickening and coalescing agents
to provide non-sagging wet films of latex on a
vertical surface of glass, polymer coatings or molded
plastic, e.g. polyethylene, polycarbonate, polyamide,
polyethylene terephthalate, polyvinylchloride, ABS,
polystyrene or polymethylmethacrylate. Such latices
preferably provide dry, coherent films of W-absorbing
copolymer of a substantially uniform thickness less
than 5 micrometers.
LAMINATES OF W -ABSORBING POLYMERIC FILNS
The latices of this invention are useful for
providing thin films, e.g. as a topcoat or an
intermediate coating, to provide long te~
stabilization against adverse effects of W light.
For instance, exposure to W light can cause white
colored substrates to yellow, and brightly colored
substrates to fade and transparent substrates to
become cloudy. The latices of W -abso~ing polymer
are useful for providing W -protective coatings on
visually informative substrates such as tajs,
displays, labels, decals and transparenci~ bearing
words or images; on flooring products such as vinyl
W094/00524 -12- PCT/US93/05938
~3~and acrylate-coated tile and sheet flooring; on
outdoor textiles such as tents, awnings, sails; on
outdoor signage such as posters, advertisements and
highway signs; on polymeric articles such as plastic
furniture, plastic glazing, hoses, vinyl siding and
roofing materials; on polymeric packaging materials
such as bags, bottles and films; and as an adhesive.
The latices can also be applied to
transparent substrates, such as glass, crystalline or
plastic windowpanes or clear plastic films, to prevent
the tr~n~ csion of W light that may be adverse to
the film or windowpane e.g. in the case of plastic
materials such as polycarbonate or acrylic glazing, or
adverse to W -sensitive materials enclosed or
protected thereby such as archival documents and
artworks, draperies, furniture, flooring and carpets.
Other transparent substrates include light source
materials sUch as diffusers and fluorescent lamp
tubes, where a coating according to this invention can
~; ;n;~h W-light emitted by the light source.
Thus, one aspect of this invention provides
laminates where a W -sensitive substrate, e.g. a
window pane, clear film, printed film, molded article,
etc., is coated with an adherent, coherent, W-
resistant vinyl polymeric film comprising:(i) 20 to 100 percent by weight W -absorbing monomer
units of vinyl-functionalized benzotriazole or vinyl-
functionalized benzophenone and 0-80 weight percent of
at least one other vinyl monomer, and
(ii) one or more additives selected from the group
consisting of plasticizer, crosslinker, nonionic
surfactant wetting agent, anionic surfactant wetting
agent and thickening agent. In some cases the W-
resistant polymeric film is a tough thermoplastic film
capable of providing other protective topcoat
qualities in addition to W-absorption. In other
cases the W -resistant polymeric film is provided as
an inner layer covered with a W-stable and durable
W094/00524 2 1 3 8 2 8 3 PCT/US93/05938
-13-
topcoat. In still other cases the W -resistant
polymer is provided as an adhesive to secure W -
sensitive material to a transparent surface. In the
case of packaging materials a coating of W -absorbing
polymer can be effective in protecting both the
packaging materials as well as the contents against
discoloration and quality or aesthetic degradation.
In certain cases, e.g. labels, decals, etc.,
it may be desirable to provide an adhesive layer on
one side of the laminate, depending on the
application, so as to take advantage of the W -
absorbing layer. For instance, such an adhesive layer
can be on the opposite side of the substrate from said
W -resistant vinyl polymeric film. In other case, the
adhesive layer can be on the W -resistant vinyl
polymeric film. In still other cases, the W -
resistant vinyl polymeric film, itself, can be
adhesive. The W-resistant coatings of this invention
are useful for protecting visually informative, W -
sensitive substrates, which can be transparent oropaque.
The W -absorbing polymer of this invention
can be advantageously applied in thin coatings, e.g.
less than 25 micrometers or ~h;nner. Preferred
coatings will be less than 10 micrometers, more
preferably less than 5 micrometers. In certain
applications, e.g. when high levels of W -absorbing
monomer is used in a copolymer, effective coatings can
be on the order of 1-2 micrometers in thickness.
Preferred coatings will comprise 40-80 percent of W -
absorbing monomer units, have a Tg greater than 20 C.
Preferred W -absorbing copolymer coatings are
sufficiently pervious to visible light that at least
70 percent of the visible light at 400 nanometers is
transmitted. The amount of W-absorbing co-monomer
and thickness of the coating are selected to reduce
the trAn~ sion of W light (between 300 and 330
W094/00524 PCT/US93/05938 -
2 ~38%~3 -14-
- nanometers) through the coating to less than 20
percent of the incident light at those wavelengths.
In certain applications, e.g. where the
copolymer is coated onto visible light-pervious
substrates such as windowpanes, bottles and
fluorescent lamp tubes, the W -absorbing copolymer
will preferably have a Tg of at least 50 C, more
preferably at least 60 C. The copolymer coating
thickness, e.g. less than 10 micrometers, and amount
of W -absorbing monomer are selected so that the
transmission of W light through the coating is less
then 10 percent of the incident light having a
wavelength between 300 and 360 nanometers, greater
than 90 percent of the incident light at wavelengths
of 400 nanometers.
OTHER APPLICATIONS
The latices of this invention are also
useful for compolln~i ng dispersed W -absorbing polymer
into W -sensitive materials such as polymer resins and
inks. In the case of polymer resins, the W -absorbing
polymer of this invention can be incorporated as a W -
stabilizing additive into polymer by conventional
methods, e.g. extruder blending or by mixing with an
other emulsion polymerized polymer latex. Acrylate
polymer resins are especially amenable to W -stabili-
zation with a W -absorbing polymers of this invention
providing non-blooming, long term resistance. The
latices of this invention provide a convenient source
of dispersed polymer for compounding into ink
formulations to provide colorfast ink, e.g. by
compounding dyes or pigment into a polymer dispersion
of this invention. In another aspect of this
invention the dispersions of W-absorbing polymer can
be used to provide "sun screen" cosmetic compositions
by compounding W -absorbing polymer in a skin lotion
base.
The invention is now described with refer-
ence to the following examples which are for purposes
W094/00524 2~ 38283 PCT/US93/05938
-15-
of illustration only and are not intended to imply any
limitation on the scope of the invention. Materials
used in these examples are identified using the
following nomenclature:
UV-I: 2-(2'-hydroxy-5-methacrylyloxyethyl-phenyl)-
2H-benzotriazole from Noramco, Inc. as
Norbloc 7966.
W -~I: 2-hydroxy-4-acrylyloxyethoxy benzophenone
from American Cyanamide as Cyasorb W -2098.
W -III: 2-(2'-hydroxy-3-tertbutyl-5-(methacrylyloxy-
ethyl)phenylpropionate)-2H-benzotriazole.
BA: butylacrylate,
BMA: butylmethacrylate
MMA: methylmethacrylate
S: styrene
AA: acrylic acid
EA: ethylacrylate
EB: Ebecryl 170 acidic acrylate from Radcure
CEA: carboxyethylacrylate
HEMA: hydroxyethylmethacrylate
2EHA: 2-ethylhexylacrylate
NMP: N-methy-2-pyrrolidone
Surfactant-l : Alipal EP-120 from Rhone-Poulenc
Surfactant-2 : Triton X-405 from Union Carbide
Plasticizer: Santicizer 160 alkyl aryl phosphate ester
plasticizer from Monsanto Company.
PAA: a non-crosslinked polyacrylic acid thickening
agent, Acrysol ASE-75 from Rohm & Haas Company.
PAA-XL: crosslinked polyacrylic acid thickening agent,
Acrysol ASE-60 from Rohm & Haas.
LX: 1.5% aqueous solution of Katon LX biocide from
Rohm & Haas Company.
Sanduvor 3051 HALS: a hindered amine light stabilizer
from Sandoz chemicals.
Tinuvin 123: bis-(1-octyloxy-2,2,6,6-tetramethyl-4-
piperidinyl)sebacate, hindered aminoether light
stabilizer from Ciba-Geigy.
W094/00524 PCT/US93/05938
~ 3 -16-
Tinuvin 292 HALS: bis(l,2,2,6,6-pentamethyl-4-piper-
idinyl) sebacate, sterically hindered tertiary
amine light stabilizer from Ciba-Geigy.
Irganox 1010 anti-oxidant and light stabilizer:
tetrakis[methylene(3,5-di-tert-butyl-4-
hydroxyhydrocinnamate)]methane, a symmetrical
molecule with four sterically hindered phenolic
hydroxy groups from Ciba-Geigy.
Irganox 245 anti-oxidant:
triethyleneglycol bis[3-(3'-tert-butyl-4'-
hydroxy-5'-methylphenyl)propionate], a
sterically hindered phenolic anti-oxidant from
Ciba-Geigy.
Beetle 60: a methylated urea formaldehyde solution,
86% resin in isopropanol, from American
Cyanamid Company,
seetle 65: a methylated urea ~ormaldehyde resin from
American Cyanamid Company,
~esimene 717! a methylated melamine f~maldeh~de
solution, 84~ resin of a trimethoxymethyl
melamine crosslinker in n-butyl alcohol from
Monsanto Company.
Resimene 745: a methylated melamine formaldehyde
solution, 84% liquid hexamethoxymethyl melamine
in n-butyl alcohol from Monsanto Company.
Resimene 7550: a methylated melamine formaldehyde
solution, an aqueous solution of 84%
dimethoxymethyl melamine from Monsanto Company.
In the following examples polymers can be
designated by the starting monomeric components using
the above abbreviations followed by a weight ratio in
parenthesis. A polymer may be designated either by
reference to the principle monomeric components, e.g.
W -I:MMA (50:50), or by reference to all of the
monomeric components, e.g. W-I:MMA:CEA:HEMA
(50:50:1:2).
W094/00524 ~ 2 1 3 8 2 8 3 PCT/US93/05938
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EXAMPLE 1
This example illustrates the preparation of
aqueous latices of W -absorbing copolymers of this
invention, i.e. copolymers of 2-(2'-hydroxy-5-
methacrylyloxyethyl-phenyl)-2H-benzotriazole (W -I).
A 50 ml flask equipped with an overhead
stirrer, condenser and a syringe septum was charged
with 3g of W -I in 4 ml of deaired distilled water, 3
g of MMA, 3 g of BA, 0.1 g of AA, 0.5 g of Surfactant-
1 and 0.5 g of Surfactant-2. The flask was purged
with nitrogen, then the mixture was heated to reflux
and emulsified. The emulsified mixture was cooled to
88 C and charged with 0.07 g of potassium persulfate
and 0.04 g of sodium bicarbonate in 4.5 ml of deaired
distilled water. The mixture was stirred for 90
minutes then cooled to room temperature. The
resulting latex of a copolymer of 2-(2'-hydroxy-5-
methacrylyloxyethyl-phenyl)-2H-benzotriazole : butyl
acrylate : methyl methacrylate : acrylic acid, i.e.
W -I:BA:MMA:AA (30:30:30:1), was filtered through a 5
micrometer filter and preserved by adding 0.05 ml of
LX biocide solution.
EXAMPLES 2-8
The procedure of Example 1 was essentially
repeated to prepare W -absorbing copolymers of the
benzotriazole W -absorbing monomer W-I in the
component weight ratios indicated in the following
Table 1.
TABLE 1
Exam~le Pol~mer C .ane.~L~ Cc ._r--L Weic~ht Ratio) ~g
1 W -I:8A:MMA:AA (30:30:30:1) 51C
2 W -I:BA:S (1:1:1) 51
3 W -I:BA:MMA:AA (30:17:43:1)
4 W -I:BA:MMA:AA:CEA (50:20:20:1:1) 76
W--I:BA:MMA:AA (28:17:7:1) 64
6 W -I:BA:CEA (40:40:3)
7 W -I:BA:EB:CEA:HEMA (40:40:2:2:3) 48
8 W -I:BA:MMA:AA:CEA:HEMA (50:34:7:2:2:3)
W094/00524 PCT/US93/05938
2 1382~3 -18-
EXAMPLE 9
This example illustrates the preparation
of an aqueous latex of a W -absorbing copolymer
according to this invention comprising 2-hydroxy-4-
acrylyloxyethoxy benzophenone (W-II).
A 100 ml flask equipped with an overhead
stirrer, condenser and a syringe septum was charged
with 5g of W-II in 31~ml of deaired distilled water,
1.1 g of S-l, 0.5 g of S-2 and 0.1 g of sodium
bicarbonate. The mixture was purged with nitrogen and
rapidly stirred for at least 15 minutes to provide an
emulsion; while stirring under a nitrogen atmosphere
the emulsion was charged with 5 g of BMA, 0.1 g of CEA
and 0.2 g of HEMA, heated to 90 C and charged with
O.1 g of potassium persulfate in 1.7 ml of deaired
distilled water. After an internal temperature rise
had peaked, the stirring rate was slowed for an
additional 15 minutes of stirring; the emulsion was
then charged with an additional o. 03 g of potassium
persulfate in 1 ml of deaired distilled water, stirred
for about 30 minutes, then cooled to room temperature.
The resulting latex of a copolymer of
2-hydroxy-4-acrylyloxyethoxy benzo- phenone:butyl
methacrylate (1:1), designated as W-II:BMA, was
filtered through a 5 micrometer filter and preserved
by adding 0.4 ml of LX biocide solution.
W094/00524 2 1 3 8 2 8 3 PCT/US93/05938
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EXAMPLES 10-23
The procedure of Example 9 was essentially
repeated to produce W -absorbing copolymers of the
benzophenone W -absorbing monomer W -II (Examples 10-
16) and W -absorbing copolymers of the benzotriazole
W -absorbing monomer W-I (Examples 17-23) in the
component weight ratios indicated in the following
Table 2.
TABL~ 2
Exam~le Polvmer Com~onent~ C .cne.~L WeLaht Ratio) Ta
9 W ~ BMA:CEA:HEMA (50:50:1:2)
W-II:BMA:CEA:HEMA (75:25:1:2) 41C
11 W -II:BMA:CEA:HEMA (30:70:1:2)
12 W -II:BMA:CEA:HEMA (20:80:1:2)
13 W--II:BMA:CEA:HE ~ (10:90:1:2)
14 W -II:BMA:CEA:HEMA (3:97:1:2)
W -II:BMA:MMA:CEA:HEMA (80:21:45:3:5) 23
16 W-II:EA:S:CEA:HEMA (80:40:20:2:3) 40
17 W-I:BMA:CEA:HEMA (75:25:1:2)
18 W--I:BMA:CEA:HEMA (50:50:1:2)
19 W -I:BMA:CEA:HEMA (30:70:1:2)
W -I:BMA:CEA:HEMA (20:80:1:2)
21 W -I:BMA:CEA:HEMA (10:90:1:2)
22 W -I:BMA:CEA:HEMA (3:97:1:2)
23 W--I:BA:CEA:HEK~ (70:38:1:2)
EXAMPLE 24
The procedure of example 9 was essentially
repeated to prepare an aqueous latex of a W -absorbing
copolymer of 2-(2'-hydroxy-3-tert-butyl-5-
(methacrylyloxyethyl)phenylpropionate)-2H-benzotria-
zole (W -III). An emulsion of 8 g of W -III in 15 ml
of deaired distilled water, 4.4 g of MMA, 2.2 g of BA,
0.15 g of CBA, 0.3 g of HEMA, 0.9 g of Surfactant-l,
0.9 g of Surfactant-2 and 0.06 g of sodium bicarbonate
was charged three times with 0.04 g of potassium
persulfate in 0.6 ml of deaired distilled water. The
copolymer designated W -III:MMA:BA:CEA:HEMA
(53:28:16:1:2), had a Tg of 42 C.
W094/00524 ~ PCT/US93/05938 -
3~ 20-
EXAMPLE 25-26
The procedure of example 9 was essentially
repeated to prepare an aqueous latex of a W -absorbing
homopolymers of W -I and W-II with minor amounts of
CEA and HEMA, e.g. the components of the homopolymer
of W -I:CEA:HEMA, Tg 92 C, and W-II:CEA:HEMA, Tg 55
C were in the weight ratio 100:1:2.
EXAMPLE 27
This example illustrates the efficacy of
films of the copolymers of this invention in absorbing
W radiation. Latices of the copolymers of W -I:BMA
of Examples 17-22 and the homopolymer of W -I of
Example 25 were coated onto glass plates and dried
providing laminates which were subjected to W light
lS transmission analysis. Figure 1 shows the effect of 1
micrometer ~hick coatings on abating the transmission
o~ w radiation. For instance, a ~ilm comprising 3
weight percent of W-absorbing monomer transmits about
7596 of the radlatlon ln the rangê ôf ~00-~50
nanometers. At least 30% W-absorbing monomer is
required to reduce UV trAnC~;csion to below 10% in the
range of 300-350 nanometers. Latices of the
copolymers of W -II:BMA of Examples 9-13 and the
homopolymer of W -II of Example 26 were coated onto
glass plates and dried providing laminates which were
subjected to W light trAn~r;~sion analysis; Figure 2
shows the effect of 1 micrometer thick coatings on
abating the transmission of W radiation.
EXAMPLE 28
An F20T12/WW fluorescent light tube without
a water repellant coating was provided with a W-
absorbing copolymer layer by brush coating the glass
lamp tube with the aqueous latex of Example 8 (diluted
with 2 volumes of water per volume of latex); ~Yc~s
liquid was brushed off and the thin wet coating was
dried by rotating the glass tube under five 250 watt
heat lamps providing a coating of about 1 micrometer
thick. The UV-absorbing copolymer-coated lamp and 2
W094/OOS24 2 1 3 8 2 8 3 PCT/US93/05938
-21-
uncoated lamps (controls) were monitored for radiation
emission in the range of 250-370 nanometers. The
light flux from the lamps was integrated over the
range of 250-370 nanometers of the W part of the
electromagnetic spectrum; the integrated radiation
flux is reported in normalized light flux units (lfu).
The reduction in light flux over the 100 hour test for
the controls indicates normal variability in lamp
output with time. The results reported in Table 3
show the utility of thin coatings of this invention in
reducing the amount of W radiation from a fluorescent
light source; Figures 3A and 3B illustrate the
reduction in the component parts of the W spectrum
effected by a 1 micrometer thick coating of the W -
absorbing copolymer measured after 100 hours ofoperation.
TABLE 3
Integrated Radiation Flux (250-370 nm)
~ Start After 100 hours
Control 1 72.8 lfu 72.4 lfu
Control 2 75.0 68.9
W -Coated 2.7 2.3
EXAMPLE 29
The procedure of Example 9 was essentially
repeated to provide an aqueous latex comprising 57.2
percent by weight dispersed polymeric compound
comprising about 98 parts by weight of a copolymer of
the monomer units W-I:BA:2-EHA (26:16.5:4.7) and
about 2 parts by weight of Plasticizer. The latex
exhibited a surface tension of 45.2 dynes/cm2.
EXAMPLE 30
Coatings were prepared by adding 5 ml of the
aqueous latex of Example 29 to volumes of water and
the wetting agents indicated in Table 4 to reduce the
surface tension of the latex to facilitate coatings of
lower surface tension substrates.
-
W094/00524 ~ ` PCT/US93/05938 -
2 ~ ~ TABLE 4
Water, ml Wetting Agent, ml Surface Tension
a. 7.5 none 44.4 dynes/cm2
b. 7.5 0.06 Surfactant II 40.8
c. 15 none 43.1
d. 15 0.2 isopropanol 42.8
e. 15 0.2 isobutanol 41.2
f. 15 0.2 n-butanol 40.2
Latex a. was coated and dried at 61 C on PET (surface
tension about 43 dynes/cm2) producing a hazy and uneven
film; latex b. provided a clear smooth film on PET.
Latices c. and d. provided uneven coatings on vinyl
flooring tiles; latices e. and f. provided even
coatings on vinyl flooring tiles.
EXAMPLE 31
Polyacrylic acid thickening agents were
added to the 5 ml quantities of the aqueous latex of
Example 29 diluted with 15 ml water to provide the
latex indicated in Table 5, where the amount of
thickener is indicated in weight percent of the latex.
Viscosity was determined using a No. 1 Spindle on a
Brookfield viscometer at 25 C and the indicated RPM.
TABLE 5
ThickenerViscosity
a. PAA-XL, 0.4%9.2 cp (6 RPM)
b. PAA-XL, 0.56%32.8 cp (6 RPM)
c. PAA-XL, 0.7%117 cp (5 RPM)
d. PAA , 0.6%400 cp (1.5 RPM)
30 Latices a. and b. provided defective coatings on vinyl
flooring tiles; latices c. and d. provided smooth
coatings on vinyl flooring tiles.
EXAMPLE 32
The procedure of Example 29 was repeated
substituting MMA for the 2EHA and omitting the
Plasticizer to provide an aqueous latex (35% solid
polymer having a Tg of 41 C) which provided hazy
films. Various coalescing agents were added to
W094/00524 ~ 2 1 3 8 ~ 8 3 PCT/US93/05918
improve film clarity. A hazy film was provided with
1% ethylene glycol monobutyl ether, commercially known
as butyl cellusove (BC) in the latex; a semi-hazy film
at 50 C with 2~ BC; a clear film at 50 C with 3 and
4 ~ BC; a clear film at 25 C with 5 and 6 % BC; a
semi-clear film at 50 C with 1% dipropylene glycol
methyl ether (DPGME); a clear film at 50 C with 2%
DPGME; a clear film at 25 C with 10% DPGME; a clear
film at 50 C with 3% tripropylene glycol methyl ether
(TPGME); and a clear film at 25 C with 5% TPGME.
EXAMPLE 33
This example illustrates the preparation of
W -absorbing polymer films cont~;ni~g radical
stabilizers and anti-oxidants. Separate 15 ml volumes
lS of aqueous latex prepared according to the procedure
of Example 29 but comprising 12.5% W -absorbing
polymer, 1% n-butanol wetting agent and 0.4 % PAA
thickening agent were mixed in a 30 ml vial with one
of the following radical stabilizers or anti-oxidants:
(a) 0.12 ml of 20% latex of Sanduvor 3051 HALS,
(b) 0.15 ml of 25~ Tinuvin 123 in NMP,
(c) 0.15 ml of 25% Tinuving 292 HALS in NMP,
(d) 0.22 ml of 2.5% Irganox 1010 anti-oxidant in
NMP, and
(e) .22 ml of Irganox 245 anti-oxidant in NMP.
Thin films of each mixture were drawn with a 25
micrometer doctor blade were dried in air, providing
clear, stabilized films of W -absorbing polymer.
EXAMPLE 34
This example illustrates the preparation of
crosslinked films of W -absorbing polymer of this
invention. Using the proc~ re of Example 9, an
aqueous latex of 24% solids W -absorbing copolymer was
prepared containing the monomer units W -I:BA:
MMA:AA;CEA (26:16:4:1:1). Separate volumes of the
latex were mixed with each of the following
W094/00524 PCT/US93/05938 -
~ 24-
- crosslinking agents:
(a) none, designated as "Control",
(b) 0.6% ammonium zirconylcarbonate,
(c) 0.8% calcium acetate,
(d) 1.6% Beetle 60,
(e) 1.2% Beetle 65,
(f) 0.5% Resimene 717,
(g) 1.5% Resimene 745, and
(h) 0 5% Resimene 7550
Ammonium chloride (0.03%) was added as catalyst to
urea formaldehyde crosslinker-containing latices; and
p-toluene sulfonic acid (0.04%) was added to the
melamine formaldehyde-cont~;~;ng latices. Each of the
latices was coated onto a glass slide using spin
coating technique, the wet films were dried in a 60 C
oven ~or three minutes. The hardness of the ~ilms
reported in Table 6 was dete. i n~ by pencil test
using the procedure of ASTM D 3363-74 after 3 days and
agaln after 5 days. ~he hardness scale runs from 6B
(softest), through 5B, 4B, 3B, 2B, B, HB, F, H, 2H,
3H, 4H and 5H to 6H (hardest).
TABLE 6
Hardness
Crosslinker 3 days5 days
Control 3B F
ammonium zirconylcarbonate HB 4H
calcium acetate 4B HB
Beetle 60 2B 6H
Beetle 65 HB 4H
Resimene 717 B 6H
Resimene 745 HB 5H
Resimene 75S0 B 5H
W O 94/00524 ~ ~ 1 3 8 2 8 ~ PC~r/US93/05938
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EXAMPLE 35
This example illustrates the preparation of a
film of W -absorbing copolymer hardened using an alkyd
resin. During preparation of a W -absorbing copolymer
according to Example 34, 5% of an alkyd resin,
designated as UN 1866 from Cargill, was added during
the let-down stage of the emulsion polymerization.
The resulting mixed latex was coated onto a glass
slide using spin coating tF~hn; que, the wet film were
dried in a 60 C oven for three minutes. After 5 days
the film exhibited a pencil test hardness of HB.
EXAMPLE 36
This example illustrates the preparation of a
film of a self-crosslinking W -absorbing copolymer. A
W -absorbing copolymer was prepared according to the
procedure of Example 34 with the addition of 1.4 parts
of glycidyl methacrylate monomer units. The latex was
coated onto a glass slide using spin coating
technique, the wet film were dried in a 60 C oven for
three minutes. After 5 days the film exhibited a
pencil test hardness of HB.
While specific embodiments have been described
herein, it should be apparent to those skilled in the
art that various modifications thereof can be made
without departing from the true spirit and scope of
the invention. Accordingly, it is intended that the
following claims cover all such modifications within
the full inventive concept.
