Acrylate or methacrylate esters of alkylene oxide adducts of alkyl/aryl phenols as wetting agents for ultraviolet curable coating compositions

The use of acrylate or methacrylate esters of polyalkylene oxide derivatives of alkyl/aryl phenols as wetting agents and adhesion promoters in ultraviolet curable systems is disclosed. These materials may be added to the ultraviolet system in a quantity between about 5 and 50 weight percent, based on the total weight of the ultraviolet curable composition.

BACKGROUND OF INVENTION 
This invention relates to ultraviolet curable coating compositions. More 
particularly this invention relates to ultraviolet curable coating 
compositions having improved wetting and adhesion properties. 
Ultraviolet curable coating compositions have been prepared from many 
materials, for example, U.S. Pat. No. 3,759,807 discloses a number of 
these systems. However, most ultraviolet curable coating compositions have 
been deficient in wetting and adhesion properties for a number of reasons. 
Predominant among these reasons is the fact that low incident energy is 
used to cure these compositions. As a result, migration and adhesion 
properties are greatly reduced. In particular, many of the prior art 
ultraviolet curable systems have been deficient in their adhesion to 
various metallic substrates, including aluminum. 
U.S. Pat. No. 3,933,935 discloses the preparation and use of 
polyethoxylated hydroxy acrylates in ultraviolet coatings. No disclosure 
is made of the fact that these materials may or may not be adhesion 
promoters, and none of the materials disclosed are based upon an alkyl 
phenol block group. 
U.S. Pat. No. 3,982,942 likewise discloses the ultraviolet curing of 
certain compositions. However, the compositions disclosed there are 
polyacrylates of dihydric phenols such as bisphenol. In this case the 
mono-acrylate is formed. 
Thus, it is an object of this invention to prepare ultraviolet curable 
coating compositions. 
It is another object of this invention to prepare such compositions which 
exhibit improved adhesion and wetting properties. 
It is another object of this invention to prepare novel monomers for use in 
ultraviolet curable coating compositions, which monomers promote better 
wetting of substrates and result in superior adhesion and pigment wetting 
properties. 
These and other objectives are obtained by preparing the compositions of 
the instant invention. 
SUMMARY OF INVENTION 
Basically, this invention involves the discovery that ultraviolet curable 
coating compositions having improved adhesion and wetting properties may 
be obtained by modifying standard ultraviolet curable coating compositions 
with an acrylate or methacrylate ester of a polyalkylene oxide derivative 
of a mono-hydric alkyl/aryl phenol at levels between about 1 and about 25 
weight percent, based upon the total weight of the ultraviolet curable 
system. 
DESCRIPTION OF INVENTION 
The alkyl/aryl phenol/alkylene oxide/acrylate or methacrylate of the 
instant invention may be represented by the general formula 
##STR1## 
wherein R.sub.1 is an alkyl group of 1-20 carbon atoms (preferably a 
hydrocarbon) or an aryl-containing group of 6-28 carbon atoms (preferably 
a hydrocarbon): m is a whole number integer of 1-3: R.sub.2 and R.sub.3 
are alkyl or aryl groups or hydrogen, and are the same or different (one 
preferably being hydrogen), as are the various R.sub.1 substituents: n is 
a whole number integer of from 1-36: and R.sub.4 is hydrogen or methyl. 
The above phenol acrylates are added to the ultraviolet curable 
compositions of the instant invention in a quantity between about 1 and 25 
weight percent. 
These alkyl/aryl phenol alkylene oxide acrylates or methacrylates may be 
prepared by known processes. For example, the alkyl/aryl phenol may be 
polyalkoxylated by reaction with ethylene oxide, propylene oxide, butylene 
oxide, styrene oxide, or any of the other monoepoxides to form a 
polyoxyalkylated phenol. Generally, this process involves reacting the 
phenol with the cyclic ether compound usually under acid catalysis. 
The preferred oxyalkylating agents are ethylene oxide, propylene oxide, 
styrene oxide, butylene oxide, and the like. The preferred alkyl/aryl 
phenols are the alkyl phenols of known types utilized as the starting 
agent for the preparation of various non-ionic surfactants by technology 
well known in the art. Examples of these materials include alkyl phenols, 
such as nonyl phenol, and the various hydrocarbon alkyl phenols; aryl 
phenols, such as benzyl phenol; and the like. 
Acrylation of the oxyalkylated phenol is accomplished by any one of several 
methods. For example, a transesterification reaction may be employed 
whereby, for example, methyl methacrylate or methyl acrylate are 
transesterified using an acid or ion exchange catalyst at temperatures 
ranging up to about 200.degree. C. with removal of the transesterification 
product (e.g., methanol, in the case of methyl methacrylate) to form the 
acrylates or methacrylates of this invention. 
In addition, acrylation or methacrylation may be carried out by a direct 
esterification method whereby acrylic acid or methacrylic acid is 
esterified with the oxyalkylated material by utilizing any of the various 
esterification catalysts, including ion exchange resins. 
Generally, the acrylic or methacrylic acids are reacted with the 
ethoxyalkylated material in an aromatic solvent such as toluene or xylene 
using acid catalysts such as sulfuric acid, methane sulfonic acid, 
p-toluene sulfonic acid, phosphoric acid, polyphosphoric acid, boron 
trifluoride and its salts, and acid based minerals of ion-exchange resins. 
The ion-exchange catalysts are sulfonic acid derivatives of crosslinked 
polystyrene resins. Alternatively, the hydrochloric salts of amino or 
cationic ion-exchange resins may be employed. 
Esterification is accompanied by removal of the water of reaction by 
standard distillation techniques. In the case of either 
transesterification or direct esterification, polymerization inhibitors 
may be employed to retard the formation of copolymer during the relatively 
high temperatures utilized during esterification or transesterification. 
Illustrative of polymerization inhibitors or nitrobenzene, phenothiazine, 
hydroquinone and its ethers, methylene blue, and the like. 
The remaining curable portion of the ultraviolet compositions of the 
instant invention contain from about 20 to 98.0 weight percent, based upon 
the total curable composition, of an alpha beta ethylenically unsaturated 
vinyl polymerizable compound containing at least two vinyl polymerizable 
groups per molecule. Included are unsaturated esters of polyols and 
particularly such esters of the alpha ethylene carboxylic acids, e.g., 
ethylene glycol diacrylate, diethylene glycol diacrylate, glycerol 
diacrylate, glycerol triacrylate, ethylene glycol dimethacrylate, 
1-3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, 
1,4-cyclohexandiol diacrylate, 1,4-benzenediol dimethacrylate, 
pentaerythritol tri- and tetraacrylate and methacrylate, 
trimethylolpropane triacrylate, trimethylolethane triacrylate, 
dipentaerythritol hexacrylate, tripentaerythritol octaacryatel, sorbitol 
hexacrylate, 1,3-propanediol diacrylate, 1,5-pentanediol dimethacrylate, 
1,6-hexanediol diacrylate, the bis-acrylates and methacrylates of 
polyethylene glycols of a molecular weight of 200-1500, and the like; 
unsaturated amides, particularly those of the alpha ethylene carboxylic 
acids, especially those of alpha, omega-diamines and oxygen-interrupted 
omega-diamines, such as methylene bis-acrylamide, methylene 
bis-methacrylamide, ethylene bis-methacrylamide, 1,6-hexamethylene 
bis-acrylamide, diethylene triamine tris-methacrylamide, 
bis(gamma-methacrylamidopropoxy)ethane, beta-methacrylamidoethyl 
methacrylate, N-beta-hydroxyethyl-beta-(methacrylamido)ethyl acrylate, and 
N,N-bis(beta-methacryloxyethyl)acrylamide; vinyl esters such as divinyl 
succinate, divinyl adipate, divinyl phthalate, divinyl terephthalate, 
divinyl benzene-1,3-disulfonate, and divinyl benzene-1,4-disulfonate; 
styrene and derivatives thereof and unsaturated aldehydes, such as 
sorbaldehyde (hexadienal). A preferred class of these additional 
polymerizable components are esters and amides of alpha-ethylene 
carboxylic acids and substituted carboxylic acids with polyols and 
polyamides wherein the molecular chain between the hydroxyl and amino 
groups is solely carbon or oxygen-interrupted carbon. 
The polyethylenic unsaturation can be present as a substituent attached to 
a preformed polymer resin, such as an alkyd, a polyester, a polyamide, a 
polyurethane or a vinyl homo- or copolymer. Also included are polymers 
containing maleic and fumaric acids or esters, as well as polymeric 
unsaturated materials prepared by reacting vinyl hydroxy or carboxy 
materials with polyepoxides, e.g., acrylic acid with the diglycidyl ether 
of bisphenol A. Also included are polymers such as polyvinyl 
acetate/acrylate, cellulose acetate/acrylate, cellulose 
acetate/methacrylate, N-acryloxymethylpolyamide, 
N-methacryloxymethylpolyamide, allyloxymethylpolyamide, etc. 
In addition to the aforementioned polyfunctional polymerizable compounds, 
compounds containing a single polymerizable ethylenically unsaturated 
group of the structure 
##STR2## 
can also be utilized. In addition to traditional "monomers", as described 
hereafter, the mono-unsaturated compounds may be polymeric materials, as 
previously described, containing on the average a single site of 
unsaturation on each polymer molecule. These monomers can be aliphatic, 
aromatic, cycloaliphatic or any variant thereof. Among the monomers are 
included styrene, 4-methylstyrene, alphamethylstyrene, and the like; 
acrylic acid and its nitrile, amide and C.sub.1 -C.sub.12 alkyl, aryl, or 
hydroxy alkyl derivatives, such as acrylonitrile, ethylacrylate, 
2-ethylhexyl acrylate, butoxy- or ethoxyethyl acrylates, hydroxyethyl 
acrylate, as well as others; the vinyl halides, such as vinyl chloride, 
vinylidene chloride, and the like; vinyl ketones such as vinyl phenyl 
ketone, vinyl methyl ketone, alpha-chlorovinyl methyl ketone, and the 
like; the vinyl thioethers such as vinyl ethyl sulfide, vinyl 
p-tolylsulfide, divinyl sulfide, and the like. Other monomers include 
vinyl ethyl sulfone, vinyl ethyl sulfoxide, vinyl sulfonic acid, sodium 
vinyl sulfonate, vinyl sulfonamide, vinyl pyridine, N-vinyl pyrrolidone, 
N-vinyl carbazole, and the like. Generally any alpha beta ethylenically 
unsaturated monomer which does not interfere with the ultraviolet curing 
mechanism may be utilized, and as such, these monomers are well known in 
the art. 
These mono-unsaturated compounds may be added in amounts up to about 60 
weight percent, based upon the total curable composition, preferably about 
10 to about 30 percent. 
The instant invention can also contain up to about 60 weight percent, based 
upon the total curable system of a polymeric material containing no 
polymerizable unsaturation. Among the polymers are the polyolefins and 
modified polyolefins, the vinyl polymers, the polyethers, the polyesters, 
the polylactones, the polyamides, the polyurethanes, the polyureas, the 
polysiloxanes, the polysulfides, the polysulfones, the polyformaldehydes, 
the phenol-formaldehyde polymers, the natural and modified natural 
polymers, the heterocyclic polymers, and the like. 
Illustrative of these polymers are the acrylic polymers such as 
poly(acrylic acid), poly(methyl acrylate), poly(ethyl acrylate), 
poly(methacrylic acid), poly(methyl methacrylate), poly(ethyl 
methacrylate); poly(vinyl chloride); poly(vinyl alcohol); 
poly(ethylene/propylene/5-ethylidenebicyclo[2.2.1]-hept-2-ene); 
polyethylene; polypropylene; synthetic rubbers, e.g., 
butadiene/acrylonitrile copolymers and chloro-2-butadiene-1,3 polymers; 
the polyesters, copolyesters, polyamides and copolyamides, such as 
polycaprolactone, poly(caprolactone/vinyl chloride), poly(ethylene glycol 
terephthalate), poly(hexamethylene succinate), poly(hexamethylene 
maleate), poly(hexamethylene carbonate), poly(caprolactam), 
poly(hexamethylene adipamide), and the like; the polyethers such as 
poly(glutaraldehyde), polyethylene oxide, polypropylene oxide, 
poly(tetrahydrofuran), polycyclohexene oxide, copolymers of ethylene oxide 
and propylene oxide with starters containing reactive hydrogen atoms such 
as the mixed copolymers using ethylene glycol, glycerol, sucrose, etc., as 
the starter; vinylidene polymers and copolymers, e.g., vinylidene 
chloride/acrylonitrile, vinylidene chloride/methacrylate and vinylidene 
chloride/vinyl acetate polymers; ethylene/vinyl acetate copolymers; the 
polyureas and polyurethanes, such as described in Polyurethanes: Chemistry 
and Technology, Volumes I and II, Sanders and Frisch, published by 
Interscience Publishers; the polycarbonates; polystyrenes; polyvinyl 
acetals, e.g., polyvinyl butyral, polyvinyl formal; the cellulose ethers, 
e.g., methyl cellulose, ethyl cellulose, and benzyl cellulose; the 
cellulose esters, e.e., cellulose acetate, cellulose acetate succinate and 
cellulose acetate butyrate; as well as the natural and modified natural 
polymers such as gutta percha, cellulose, gelatin, starch, silk, wool, and 
the like; the siloxane polymers and copolymers; the formaldehyde polymers 
such as polyformaldehyde; formaldehyde resins such as phenol-formaldehyde, 
melamine-formaldehyde, urea-formaldehyde, aniline-formaldehyde and 
acetone-formaldehyde; phenolic resins and the like. 
If desired, the instant systems can also contain immiscible polymeric or 
non-polymeric organic or inorganic fillers or reinforcing agents, e.g., 
the organophilic silicas, bentonites, silica, powdered glass, colloidal 
carbon, as well as various other types of dyes and pigments, in varying 
amounts. The fillers are useful in improving the strength, reducing tack 
and as coloring agents in the coatings of this invention. The 
photosensitizers or photoinitiators used in the instant invention fall 
into many classes and include compounds such as benzoin derivatives, as 
disclosed in German Pat. No. F523401VC/396, acetophenone, propiophenone, 
xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, 
triphenylamine, carbazole, 3- or 4-methylacetophenone, 3- or 
4-pentylacetophenone, 3- or 4-methoxyacetophenone, 3- or 
4-bromo-acetophenone, 3- or 4-allylacetophenone, p-diacetylbenzene, 3- or 
4-methoxybenzophenone, 3- or 4-methylbenzophenone, 3- or 
4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 
4-chloro-4'benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 
thioxanthone, and chlorinated thioxanthones, 3-chloro-8-nonylxanthone, 
3-methoxyxanthone, 3-iodo-7-methoxyxanthone, and the like. 
Also included are the acetophenone photosensitizers of the type described 
in U.S. Pat. No. 3,715,293, having the structure 
##STR3## 
wherein R is alkyl of from 1-8 carbon atoms, or aryl with 6 carbon atoms, 
and R' is hydrogen, alkyl of from 1-8 carbon atoms, aryl of from 6-14 
carbon atoms or cycloalkyl or 5-8 carbon atoms. 
The alkylphenone photosensitizers having the formula 
##STR4## 
the benzophenone type photosensitizers having the formula 
##STR5## 
the tricyclic fused ring type having the formula 
##STR6## 
and the pyridyl type having the formula 
##STR7## 
wherein the various substitutents are as further described in U.S. Pat. 
No. 3,759,807, are also included. 
Other photosensitizers include 1- and 2-chloroanthraquinone, 
2-methylanthraquinone, 2-tertiary butyl anthraquinone, 
octamethylanthraquinone, 1-4-naphthoquinone, 9-10-phenanthrenequinone, 
1,2-benzanthraquinone, 2-3-benzanthraquinone, 2-methyl-1,4-naphthoquinone, 
2-3-dichloronaphthoquinone, 1-4-dimethylanthraquinone, 
2-3-dimethylanthraquinone, 2-phenylanthraquinone, 
2-3-diphenylanthraquinone, sodium salts of anthraquinone alpha-sulfonic 
acid, 3-chloro-2-methylanthraquinone, and the like. Other photoinitiators 
which are also useful are described in U.S. Pat. No. 2,760,863 and include 
vicinal ketadonyl compounds, such as diacetyl benzyl, etc., alpha 
ketadonyl alcohols, such as benzoin, pivaloin, etc., acyloin ethers, e.g., 
benzoin methyl and ethyl ethers, etc., alpha hydrocarbon substituted 
aromatic acyloins, including alpha-methyl benzoin, alpha-allyl benzoin, 
and alpha-phenyl benzoin. Also included are the diacylhalomethanes, 
corresponding to one of the general formulas: 
##STR8## 
wherein halogen represents a halogen atom such as chlorine or bromine; R 
represents a hydrogen atom, a chlorine or bromine atom, or an acetyloxy 
group; R' and R" (same or different) represent a benzoyl group, a 
nitrobenzoyl group, a dimethylamino benzoyl group, a phenyl sulfonyl 
group, a carboxy phenyl sulfonyl group, a methylphenyl sulfonyl group, or 
a naphthoyl group; and X and Y (same or different) represent a carbonyl 
group or a sulfonyl group. Included are 2-bromo-1,3-diphenyl-1,3-propane 
dione; 2,2-dibromo-1,3-indane dione; 2,2-dibromo-1,3-diphenyl-1,3-propane 
dione; 2-bromo-2-(phenylsulfonyl acetal phenone) and the like, as further 
described in U.S. Pat. No. 3,615,455. 
Other photoinitiators are cataloged by G, Delzenne in Industrie Cimique 
Belge, 24 (1959), 739,764. Most preferred among the added initiators are 
benzoin and its alkyl ethers, benzophenone and its derivatives, as in 
Formula III, xanthone, thioxanthones, chlorinated thioxanthones, and 
acetophenone derivatives, as set out in Formula I, and halogenated, 
aliphatic and aromatic polychlorinated biphenyls and polyphenyls. 
The photosensitizers can be added in an amount of about 0.5 to about 15 
weight percent, based upon the total curable system, preferably about 0.1 
to about 5 percent. 
Although not required for every photoinitiator, certain organic amines can 
be added to the photosensitizers above-described to further enhance the 
cure rate of the compositions of the instant invention in amounts up to 
about 500 weight percent, of the photosensitizer, preferably up to about 
50 weight percent. The amines can be primary, secondary, or tertiary, and 
are illustrated by amine compounds such as methylamine, dimethylamine, 
trimethylamine, diethylamine, triethylamine, propylamine, isopropylamine, 
diisopropylamine, trisopropylamine, butylamine, tributylamine, 
t-butylamine, 2-methylbutylamine, N-methyl-N-butylamine, methanolamine, 
ethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, 
dimethylethanolamine, isopropanolamine, propanolamine, diisopropanolamine, 
triisopropanolamine, tricyclohexenylamine, tricyclohexadienylamine, 
tricyclopentadienylamine, N-methyl-N-cyclohexylamine, 
N-2-ethylhexyl-N-cyclohexylamine, diphenylamine, phenyldimethylamine, 
methylphenylamine, ditolylamine, trixylylamine, tribenzylamine, 
triphenethylamine, benzyldimethylamine, benzyldihexylamine, and the like. 
The preferred organic amines are the tertiary amines, with the alkanol 
amines being most preferred. The specific preferred amines activators are 
triethanolamine, morpholine and methyldiethanolamine. 
The compositions of the instant invention after being prepared in the 
ratios as set out above can be applied to the material to be coated by 
conventional spraying means, and may, if desired, be dried under ambient 
or oven conditions to provide coating films on the substrate. The 
substrate can be of any composition, e.g., wood, metal, paper, plastic, 
fabric, fiber, ceramic, concrete, plaster, glass, etc. 
The compositions of the instant invention, including the phenol acrylates, 
show excellent utility in applications where the substrate is one to which 
ultraviolet coatings have traditionally adhered to only with difficulty. 
Thus the instant invention is particularly applicable to coating 
compositions which are applied to metal, plastic, glass, etc. 
Typically, a mixture of the compositions described above in combination 
with the initiator and, where utilized, the amine activator, is prepared 
and the composition sprayed onto the desired substrate. It is then exposed 
to electromagnetic radiation having wave lengths of above about 2000 
Angstrom units, preferably from about 2000 up to about 5000 Angstroms. 
Exposure should be from a source located about 1 to 5 inches from the 
coating for a time sufficient to cause crosslinking of the compositions 
and can range from about 0.1 seconds up to about 1 min./linear ft. 
Generally, the light radiation will have power of about 200 watts per 
linear inch. 
The light radiation can be utraviolet light generated from low, medium and 
high pressure mercury lamps. This equipment is readily available and its 
use is well known to those skilled in the art of radiation chemistry.

In the following examples, all parts and percentages are by weight, unless 
otherwise indicated. 
EXAMPLE I 
A composition containing 50 grams of trimethylolpropane triacrylate, 36 
grams of an acrylate ester of ethoxylated nonylphenol containing 6 
ethylene oxide units, and 4 grams of benzoin isobutyl ether was prepared. 
A 0.5 mil coating was cast on an aluminum panel, and it was cured under a 
200 watt high pressure mercury vapor UV lamp for 0.5 seconds. The cured 
coating had excellent adhesion to the aluminum panel and good solvent 
resistance. 
EXAMPLE II 
27 grams of poly(methyl methacrylate) (M.W. 36,000) was dissolved in a 
solution containing 30 grams of 1,4-butanediol diacrylate, 20 grams of 
trimethylolpropane trimethacrylate, 15 grams of ethoxylated octylphenol 
containing 10 ethylene oxide units, 4 grams of benzophenone and 4.0 grams 
of diethanolamine. 
A 0.6 mil coating was cast on an unprimed steel panel and it was cured 
under a 200 watt medium pressure mercury vapor UV lamp for 0.5 seconds. 
The cured coating adhered well to the unprimed steel. 
EXAMPLE III 
An ultraviolet-cured coating for vinyl tile was prepared by dissolving 20 
grams of EPI-REZ 510 diacrylate (Celanese) into a solution containing 40 
grams of hexanediol diacrylate, 10 grams poly(butyl acrylate) (M.W. 
24,500), 25 grams of ethoxylated dodecyl phenol containing 10 ethylene 
oxide units, and 5 grams of benzoin isopropyl ether. 
A 0.5 mil film was cast on vinyl tile and it was cured as in Examples I and 
II. The cured coating adhered well to the vinyl tile and provided a glossy 
finish. 
EXAMPLE IV 
A composition was prepared containing 25 grams of trimethylolpropane 
triacrylate, 20 grams of poly(ethyl acrylate) (M.W. 35,500), 20 grams of 
hexanediol diacrylate, 25 grams of an ethoxylated nonylphenol containing 4 
ethylene oxide units, 5 grams of benzophenone, and 5 grams of 
triethanolamine. 
A 1.0 mil coating was cast on an unfinished luan mahogany veneer panel, and 
it was cured 2.0 seconds in an ultraviolet apparatus in the manner of the 
previous Examples. The cured coating adhered well to the wood panel and 
formed a smooth shiny finish.