Aqueous latices adapted to forming visible light transparent, coherent polymeric films, e.g. in laminates, as protective coatings or as adhesives, comprising colloidal particles of a UV-absorbing polymer less than 5 micrometers in diameter. Useful UV-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 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 windows, tags, labels, flooring, tents, awnings, containers and other UV-susceptible substrates.

Disclosed herein are aqueous latices of UV-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 INVENTION 
Japanese Kokai 57-45169 and 58-38269 disclose solvent polymerization of 
copolymers containing UV-absorbing monomer units useful as coating 
additives. Specifically disclosed copolymers comprise up to about 22 mole 
percent (about 30 weight percent) benzotriazole UV-absorbing monomer units 
an a non-UV-absorbing comonomer such as methyl methacrylate, styrene or 
butyl acrylate. 
U.S. Pat. No. 4,528,311 discloses optically clear UV-absorbing copolymers 
comprising up to 20 weight percent of 
2-hydroxy-5-acrylyloxyphenyl-2H-benzotriazoles for UV-absorbing films that 
afford 85% absorption at 400 nanometers and 1 millimeter thickness. 
U.S. Pat. No. 4,576,870 discloses coextruded laminates comprising 
UV-absorbing polymer coatings (10-100 microns thick) comprising up to 20 
weight percent of 2-hydroxyphenylbenzotriazole monomers. 
U.S. Pat. Nos. 4,785,063 and 4,892,915 disclose incorporation of 
2-(2-hydroxy-5-acryloyloxyalkyl)-phenyl-2H-benzotriazoles UV-absorbing 
copolymerizable additives at low levels, e.g. at about 2 percent, in 
acrylate coatings which are cured by E-beam radiation. 
U.S. Pat. No. 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. 
EPO 0 282 294 discloses optically clear silicone polymers containing 
vinylsilylalkoxy arylbenzotriazole monomer units. 
U.S. Pat. Nos. 3,745,010 and 3,761,272 disclose emulsion polymerized, 
UV-absorbing benzotriazole acrylate copolymers useful in photographic 
applications, e.g. to protect photographic film against UV 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 UV-absorbing copolymers provided photographic filters 
having a maximum absorption at 352 nm. 
U.S. Pat. Nos. 4,612,358 and 4,652,656 disclose UV-absorbing copolymers of 
20-60 percent benzotriazole-functionalized acrylamides useful for 
protective layers for UV 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 UV protective layer for a UV sensitive plastic. 
U.S. Pat. Nos. 4,443,534 and 4,455,368 disclose UV-absorbing copolymer 
latex useful in UV-absorbing protective layers for photographic film, e.g. 
light sensitive silver halide material. 
SUMMARY OF THE INVENTION 
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 aqueous 
medium, wherein said particles are less than 5 micrometers in diameter. 
Useful UV-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 UV-susceptible substrates; such coatings can be applied 
as topcoats, as intermediate layers in a laminate or as adhesive layers. 
The specific application of the UV-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 UV 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.

DETAILED 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 colloidal 
particles of a UV-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 UV-absorbing polymers of this invention 
include homopolymers of vinyl-functionalized UV-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 UV-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 preferably, the UV-absorbing copolymers of 
this invention comprise at least 30 weight percent vinyl-functionalized 
UV-absorbing monomer, even more preferably at least 40 weight percent and 
not more than 80 weight percent of UV-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 
methylmethacrylate, 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, 
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-UV-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-UV-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 UV-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 techniques 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 0.05 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.degree. C. 
to 150.degree. C. depending on the desired application. For applications 
that are exposed to high temperature, preferred coatings of UV-absorbing 
copolymers have a Tg greater than 20.degree. C., preferably at least 
50.degree. 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. Crosslinking monomer units can comprise a 
variety of pendant groups, e.g. vinyl, acid, hydroxyl, epoxy or isocyante 
groups or mixtures thereof. For instance, UV-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 incorporated into the dispersed 
polymer or be independently dispersed in the aqueous medium. Depending on 
the crosslinkable pendant groups in the UV-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 UV-absorbing 
copolymer film can be also be achieved by blending a latex of the 
UV-absorbing copolymer with a latex of a crosslinked network-forming resin 
such as an alkyd resin. Crosslinking can promote high Tg, toughness, 
solvent resistance. Thus, preferred latices which are more amenable to 
coating applications comprise suspended polymer having a Tg lower than the 
Tg desired for the polymer coating application. Such latices comprise 
copolymer having a Tg greater than 0.degree. C., preferably greater than 
20.degree. C. 
For many applications desirable UV-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.degree. C., 
preferably to less than 30.degree. 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 tetrahydrofuran; 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 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-pyrrolidone. 
In many cases it is advantageous to incorporate plasticizer into the 
polymer of this invention, e.g. to lower the temperature softening 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 UV-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 
compounding 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 polymerization. Plasticizer can also be incorporated by 
intimately mixing dispersed plasticizer with dispersed polymer. Useful 
plasticizer can include alkyl adipate esters such as dioctyl adipate, 
alkyl aryl adipate 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 methylcellulose, polyacrylic acids and salts thereof, and 
water soluble polyuretane thickeners such as non-ionic polyethylene oxide 
urethane block copolymers; a variety of useful thickening 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.degree. C. greater than 40 centipoises, 
preferably greater than 100 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.degree. C. is about 45 dynes/cm.sup.2 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, about 30 for polypropylene and about 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 minimal amount of surfactant to maintain a 
colloidal suspension of polymer may have a surface tension in the range of 
45 to 50 dynes/cm.sup.2. 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, isobutanol, n-pentanol, n-hexanol and 
cyclohexanol. Preferred alcohol wetting agents are the C.sub.3 and C.sub.4 
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/cm.sup.2, more preferably 
less than 41 dynes/cm.sup.2. 
A preferred aspect of this invention provides latex of UV-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 UV-absorbing copolymer of a substantially uniform thickness less 
than 5 micrometers. 
Laminates of UV-Absorbing Polymeric Films 
The latices of this invention are useful for providing thin films, e.g. as 
a topcoat or an intermediate coating, to provide long term stabilization 
against adverse effects of UV light. For instance, exposure to UV light 
can cause white colored substrates to yellow, and brightly colored 
substrates to fade and transparent substrates to become cloudy. The 
latices of UV-absorbing polymer are useful for providing UV-protective 
coatings on visually informative substrates such as tags, displays, 
labels, decals and transparencies bearing words or images; on flooring 
products such as vinyl 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 
transmission of UV 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 UV-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 diminish UV-light emitted by the light 
source. 
Thus, one aspect of this invention provides laminates where a UV-sensitive 
substrate, e.g. a window pane, clear film, printed film, molded article, 
etc., is coated with an adherent, coherent, UV-resistant vinyl polymeric 
film comprising: 
(i) 20 to 100 percent by weight UV-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 
UV-resistant polymeric film is a tough thermoplastic film capable of 
providing other protective topcoat qualities in addition to UV-absorption. 
In other cases the UV-resistant polymeric film is provided as an inner 
layer covered with a UV-stable and durable topcoat. In still other cases 
the UV-resistant polymer is provided as an adhesive to secure UV-sensitive 
material to a transparent surface. In the case of packaging materials a 
coating of UV-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 UV-absorbing layer. For 
instance, such an adhesive layer can be on the opposite side of the 
substrate from said UV-resistant vinyl polymeric film. In other case, the 
adhesive layer can be on the UV-resistant vinyl polymeric film. In still 
other cases, the UV-resistant vinyl polymeric film, itself, can be 
adhesive. The UV-resistant coatings of this invention are useful for 
protecting visually informative, UV-sensitive substrates, which can be 
transparent or opaque. 
The UV-absorbing polymer of this invention can be advantageously applied in 
thin coatings, e.g. less than 25 micrometers or thinner. Preferred 
coatings will be less than 10 micrometers, more preferably less than 5 
micrometers. In certain applications, e.g. when high levels of 
UV-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 UV-absorbing monomer units, have a Tg greater 
than 20.degree. C. Preferred UV-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 UV-absorbing 
co-monomer and thickness of the coating are selected to reduce the 
transmission of UV light (between 300 and 330 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 UV-absorbing copolymer will preferably have a Tg of at 
least 50.degree. C., more preferably at least 60.degree. C. The copolymer 
coating thickness, e.g. less than 10 micrometers, and amount of 
UV-absorbing monomer are selected so that the transmission of UV 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 compounding dispersed 
UV-absorbing polymer into UV-sensitive materials such as polymer resins 
and inks. In the case of polymer resins, the UV-absorbing polymer of this 
invention can be incorporated as a UV-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 UV-stabilization with a UV-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 UV-absorbing 
polymer can be used to provide "sun screen" cosmetic compositions by 
compounding UV-absorbing polymer in a skin lotion base. 
The invention is now described with reference to the following examples 
which are for purposes 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. 
UV-II: 2-hydroxy-4-acrylyloxyethoxy benzophenone from American Cyanamide as 
Cyasorb UV-2098. 
UV-III: 
2-(2'-hydroxy-3-tertbutyl-5-(methacrylyloxyethyl)phenylpropionate)-2H-benz 
otriazole. 
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-1: 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. 
Tinuvin 292 HALS: bis(1,2,2,6,6-pentamethyl-4-piperidinyl) 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, 
Beetle 65: a methylated urea formaldehyde resin from American Cyanamid 
Company, 
Resimene 717: a methylated melamine formaldehyde 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. UV-I:MMA (50:50), or by reference 
to all of the monomeric components, e.g. UV-I:MMA:CEA:HEMA (50:50:1:2). 
EXAMPLE 1 
This example illustrates the preparation of aqueous latices of UV-absorbing 
copolymers of this invention, i.e. copolymers of 
2-(2'-hydroxy-5-methacrylyloxyethyl-phenyl)-2H-benzotriazole (UV-I). 
A 50 ml flask equipped with an overhead stirrer, condenser and a syringe 
septum was charged with 3g of UV-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.degree. 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. UV-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 UV-absorbing 
copolymers of the benzotriazole UV-absorbing monomer UV-I in the component 
weight ratios indicated in the following Table 1. 
TABLE 1 
__________________________________________________________________________ 
Example 
Polymer Components 
Component Weight Ratio) 
Tg 
__________________________________________________________________________ 
1 UV-I:BA:MMA:AA (30:30:30:1) 51.degree. C. 
2 UV-I:BA:S (1:1:1) 51 
3 UV-I:BA:MMA:AA (30:17:43:1) -- 
4 UV-I:BA:MMA:AA:CEA 
(50:20:20:1:1) 
76 
5 UV-I:BA:MMA:AA (28:17:7:1) 64 
6 UV-I:BA:CEA (40:40:3) -- 
7 UV-I:BA:EB:CEA:HEMA 
(40:40:2:2:3) 
48 
8 UV-I:BA:MMA:AA:CEA:HEMA 
(50:34:7:2:2:3) 
-- 
__________________________________________________________________________ 
EXAMPLE 9 
This example illustrates the preparation of an aqueous latex of a 
UV-absorbing copolymer according to this invention comprising 
2-hydroxy-4-acrylyloxyethoxy benzophenone (UV-II). 
A 100 ml flask equipped with an overhead stirrer, condenser and a syringe 
septum was charged with 5 g of UV-II in 31 ml of deaired distilled water, 
1.1 g of S-1, 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.degree. C. and charged with 0.1 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 0.03 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 UV-II:BMA, was filtered through a 5 
micrometer filter and preserved by adding 0.4 ml of LX biocide solution. 
EXAMPLES 10-23 
The procedure of Example 9 was essentially repeated to produce UV-absorbing 
copolymers of the benzophenone UV-absorbing monomer UV-II (Examples 10-16) 
and UV-absorbing copolymers of the benzotriazole UV-absorbing monomer UV-I 
(Examples 17-23) in the component weight ratios indicated in the following 
Table 2. 
TABLE 2 
__________________________________________________________________________ 
Example 
Polymer Components 
Component Weight Ratio) 
Tg 
__________________________________________________________________________ 
9 UV-II:BMA:CEA:HEMA 
(50:50:1:2) -- 
10 UV-II:BMA:CEA:HEMA 
(75:25:1:2) 41.degree. C. 
11 UV-II:BMA:CEA:HEMA 
(30:70:1:2) -- 
12 UV-II:BMA:CEA:HEMA 
(20:80:1:2) -- 
13 UV-II:BMA:CEA:HEMA 
(10:90:1:2) -- 
14 UV-II:BMA:CEA:HEMA 
(3:97:1:2) -- 
15 UV-II:BMA:MMA:CEA:HEMA 
(80:21:45:3:5) 
23 
16 UV-II:EA:S:CEA:HEMA 
(80:40:20:2:3) 
40 
17 UV-I:BMA:CEA:HEMA 
(75:25:1:2) -- 
18 UV-I:BMA:CEA:HEMA 
(50:50:1:2) -- 
19 UV-I:BMA:CEA:HEMA 
(30:70:1:2) -- 
20 UV-I:BMA:CEA:HEMA 
(20:80:1:2) -- 
21 UV-I:BMA:CEA:HEMA 
(10:90:1:2) -- 
22 UV-I:BMA:CEA:HEMA 
(3:97:1:2) -- 
23 UV-I:BA:CEA:HEMA 
(70:38:1:2) -- 
__________________________________________________________________________ 
EXAMPLE 24 
The procedure of example 9 was essentially repeated to prepare an aqueous 
latex of a UV-absorbing copolymer of 
2-(2'-hydroxy-3-tert-butyl-5-(methacrylyloxyethyl)phenylpropionate)-2H-ben 
zotriazole (UV-III). An emulsion of 8 g of UV-III in 15 ml of deaired 
distilled water, 4.4 g of MMA, 2.2 g of BA, 0.15 g of CEA, 0.3 g of HEMA, 
0.9 g of Surfactant-1, 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 
UV-III:MMA:BA:CEA:HEMA (53:28:16:1:2), had a Tg of 42.degree. C. 
EXAMPLES 25-26 
The procedure of example 9 was essentially repeated to prepare an aqueous 
latex of a UV-absorbing homopolymers of UV-I and UV-II with minor amounts 
of CEA and HEMA, e.g. the components of the homopolymer of UV-I:CEA:HEMA, 
Tg 92.degree. C., and UV-II:CEA:HEMA, Tg 55.degree. 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 UV radiation. Latices of the copolymers of UV-I:BMA 
of Examples 17-22 and the homopolymer of UV-I of Example 25 were coated 
onto glass plates and dried providing laminates which were subjected to UV 
light transmission analysis. FIG. 1 shows the effect of 1 micrometer thick 
coatings on abating the transmission of UV radiation. For instance, a film 
comprising 3 weight percent of UV-absorbing monomer transmits about 75% of 
the radiation in the range of 300-350 nanometers. At least 30% 
UV-absorbing monomer is required to reduce UV transmission to below 10% in 
the range of 300-350 nanometers. Latices of the copolymers of UV-II:BMA of 
Examples 9-13 and the homopolymer of UV-II of Example 26 were coated onto 
glass plates and dried providing laminates which were subjected to UV 
light transmission analysis; FIG. 2 shows the effect of 1 micrometer thick 
coatings on abating the transmission of UV radiation. 
EXAMPLE 28 
An F20T12/WW fluorescent light tube without a water repellant coating was 
provided with a UV-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); excess 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 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 UV 
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 UV radiation 
from a fluorescent light source; FIGS. 3A and 3B illustrate the reduction 
in the component parts of the UV spectrum effected by a 1 micrometer thick 
coating of the UV-absorbing copolymer measured after 100 hours of 
operation. 
TABLE 3 
______________________________________ 
Integrated Radiation Flux (250-370 nm) 
Lamp Start After 100 hours 
______________________________________ 
Control 1 72.8 lfu 72.4 lfu 
Control 2 75.0 68.9 
UV-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 
UV-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/cm.sup.2. 
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. 
TABLE 4 
______________________________________ 
Water, ml Wetting Agent, ml 
Surface Tension 
______________________________________ 
a. 7.5 none 44.4 dynes/cm.sup.2 
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.degree. C. on PET (surface tension 
about 43 dynes/cm.sup.2) 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.degree. C. and the indicated RPM. 
TABLE 5 
______________________________________ 
Thickener Viscosity 
______________________________________ 
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) 
______________________________________ 
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.degree. C.) which provided hazy films. Various 
coalescing agents were added to 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.degree. C. with 
2% BC; a clear film at 50.degree. C. with 3 and 4% BC; a clear film at 
25.degree. C. with 5 and 6% BC; a semi-clear film at 50.degree. C. with 1% 
dipropylene glycol methyl ether (DPGME); a clear film at 50.degree. C. 
with 2% DPGME; a clear film at 25.degree. C. with 10% DPGME; a clear film 
at 50.degree. C. with 3% tripropylene glycol methyl ether (TPGME); and a 
clear film at 25.degree. C. with 5% TPGME. 
EXAMPLE 33 
This example illustrates the preparation of UV-absorbing polymer films 
containing radical stabilizers and anti-oxidants. Separate 15 ml volumes 
of aqueous latex prepared according to the procedure of Example 29 but 
comprising 12.5% UV-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) 0.22 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 UV-absorbing 
polymer. 
EXAMPLE 34 
This example illustrates the preparation of crosslinked films of 
UV-absorbing polymer of this invention. Using the procedure of Example 9, 
an aqueous latex of 24% solids UV-absorbing copolymer was prepared 
containing the monomer units UV-I:BA: MMA:AA;CEA (26:16:4:1:1). Separate 
volumes of the latex were mixed with each of the following 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-containing latices. Each of the latices 
was coated onto a glass slide using spin coating technique, the wet films 
were dried in a 60.degree. C. oven for three minutes. The hardness of the 
films reported in Table 6 was determined by pencil test using the 
procedure of ASTM D 3363-74 after 3 days and again after 5 days. The 
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 days 5 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 7550 B 5H 
______________________________________ 
EXAMPLE 35 
This example illustrates the preparation of a film of UV-absorbing 
copolymer hardened using an alkyd resin. During preparation of a 
UV-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 technique, the wet film were dried in a 
60.degree. 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 
UV-absorbing copolymer. A UV-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.degree. 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.