(N-Substituted carbamoyloxy) alkanoyloxyalkyl acrylate esters produced by reacting an hydroxyalkyl acrylate with a lactone monomer and capping the resulting adduct with an isocyanate. The resulting product is useful in ink, paint or adhesive formulations curable by thermal or radiation means.

BACKGROUND OF THE INVENTION 
Compounds such as 2-(N-methyl carbamoyloxy) ethyl acrylate are well known 
with the generic class disclosed in U.S. Pat. No. 3,479,328, and U.S. Pat. 
No. 3,674,838. These compounds have been found particularly effective in 
radiation curable compositions since they impart desirable properties to 
the prepared compositions and to the cured compositions. However, due to 
their sensitizing effect and toxicity they must be handled with extreme 
caution and, as a consequence, these features detract from their general 
acceptance and use. 
SUMMARY OF THE INVENTION 
The novel (N-substituted carbamoyloxy)alkanoyloxyalkyl acrylate esters of 
this invention are those defined by the structural formula: 
##STR1## 
wherein R is an unsubstituted or substituted (i) linear or branched alkyl 
group having from 1 to 4 carbon atoms, or (ii) aryl, alkaryl or aralkyl 
group having 6 or 10 ring carbon atoms, or (iii) cycloalkyl group having 
from 5 to 8 ring carbon atoms when x is 1, and polyvalent alkylene, 
arylene, alkarylene or cycloalkylene having carbon atom values defined for 
(i) to (iii) supra and a valence equal to the value of x when x is greater 
than 1; wherein the substituents on the R group are not reactive with the 
isocyanato radical; R' is hydrogen or alkyl or alkoxy having from 1 to 4 
carbon atoms; R" is a linear or branched divalent alkylene of 1 to 10 
carbon atoms, preferably 2 to 4 carbon atoms, divalent cycloalkylene of 5 
to 12 carbon atoms, preferably 6 to 8 carbon atoms, or divalent arylene of 
6 to 10 ring carbon atoms; X is hydrogen, methyl or cyano; x has a value 
of from 1 to 4; y is an integer having an average value of from 1 to 20, 
preferably from 1 to 6 and most preferably from 1to 4; and z is an integer 
having a value of from 3 to 10, preferably from 5 to 6. 
DESCRIPTION OF THE INVENTION 
The novel componds of this invention are produced, preferably, by a 
two-step process that can, if desired, be carried out sequentially in the 
same reactor. The compounds have monofunctionality when a monoisocyanate 
is used in the second step of the reaction and polyfunctionality when a 
polyisocyanate is used. The polyfunctional acrylyl compounds can be used 
as crosslinkers in formulated compositions. 
In the first step of the reaction a hydroxyalkyl acrylate of the general 
formula: 
##STR2## 
wherein X and R" are as previously defined, is reacted with a lactone of 
the general formula: 
##STR3## 
wherein R' and z are as previously defined, to produce the adduct. 
Illustrative of suitable hydroxyalkyl acrylates or methacrylates or 
cyanoacrylates one can mention hydroxyethyl acrylate, hydroxyethyl 
methacrylate, hydroxyethyl cyanoacrylate, hydroxypropyl acrylate, 
hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxydecyl acrylate, 
hydroxydecyl cyanoacrylate, hydroxycyclohexyl acrylate, hydroxycyclohexyl 
methacrylate, hydroxycyclooctyl acrylate, and the like. Those skilled in 
the art are fully familiar with this class of compounds and mixtures can 
be used. 
Illustrative of suitable lactones one can mention butyrolactone, 
epsilon-caprolactone, zeta-enantholactone, delta-valerolactone; the 
alkyl-delta valerolactones such as the methyl-, ethyl-, hexyl-, 
dimethyl-delta-valerolactones; the alkyl epsilon-caprolactones such as the 
methyl-, ethyl-, hexyl-, dimethyl-, diethyl-, di-n-propyl-, di-n-hexyl-, 
di-iso-propyl-, trimethyl-, triethyl-, tri-n-propyl-epsilon-caprolactones, 
and the like. The lactones are known to those skilled in the art and 
mixtures can be used. 
The reaction between the hydroxyalkyl acrylates and lactone is preferably 
carried out in contact with a catalyst. The Lewis Acids are suitable as 
catalyts and illustrative thereof one can mention boron trifluoride 
etherate, stannic chloride, zinc chloride, magnesium perchlorate, bis 
(trifluoroethyl sulfonyl) tin, and the like. The catalyst is present in a 
catalytically effective amount; this can be from 0.1 to 1 weight percent, 
based on the total weight of reactants charged, preferably from 0.2 to 0.5 
weight percent, with from 0.25 to 0.35 weight percent most preferred. 
In the reaction from 1 to about 80 moles, or more; preferably from 1 to 24 
moses, of lactone are reacted per mole of hydroxyalkyl acrylate. The 
amount used is that required to give the desired y value in formula I; as 
previously indicated the preferred y value is from 1 to 6 and the most 
preferred value is from 1 to 4. 
The reaction can be carried out at atmospheric or superatmospheric 
pressure, pressure is not critical though modest pressure can develop in a 
sealed reactor. The reaction time will vary dependent upon the particular 
reactants, catalysts, temperature, and batch size involved in any 
paticular instance. 
The reaction temperature will vary from about 20.degree. C. to about 
125.degree. C. and is generally from about 25.degree. C. to about 
80.degree. C., preferably from about 55.degree. C. to 75.degree. C. 
To minimize olefinic bond free radical polymerization an inhibitor such as 
the monoethyl ether of hydroquinone is added at a concentration of from 
about 0.01 to 0.1 weight percent. Any of the other known inhibitors can be 
used. 
In carrying out the first step reaction of the lactone with the 
hydroxyalkyl acrylate one can charge the hydroxyalkyl acrylate and 
catalyst to a reactor equipped with stirring, condensing and cooling means 
and then heat the contents to the selected temperature within the range 
heretofore stated. When this charge is at the desired reaction temperature 
the lactone feed is started and cooling is supplied as required to 
maintain the desired temperature during the exothermic feed period. When 
an exotherm is no longer observed, heating is continued for an additional 
period of one to three hours at the selected reaction temperature after 
feed of lactone has been terminated. The resulting adduct can be used in 
this form in the second step of the reaction, or it can be treated and the 
semi-refined or refined adduct can then be used in the second step of the 
reaction. 
Any conventional refining procedure can be used when the adduct is desired 
in a purer state. Thus, following the additional heating period the 
residual adduct can be neutralized with a base or a diatomaceous earth 
material such as magnesium silicate, stirred, heated at reduced pressure 
to remove volatiles, and then filtered to remove solid residues. Other 
procedures can be used that are apparent to those skilled in the art. 
In the second step of the reaction the adduct whose preparation was 
described above is reacted with an organic isocyanate. The suitable 
isocyanates can be mono-, di-, tri- or tetra-isocyanates and many such 
compounds are known and are commercially available. They can be used 
singly or in admixture and illustrative thereof one can mention methyl 
isocyanate, ethyl isocyanate, chloroethyl isocyanate, chlorobutoxypropyl 
isocyanate, hexyl isocyanate, phenyl isocyanate, the o-, m-, and 
p-chlorophenyl isocyanates, benzyl isocyanate, naphthyl isocyanate, 
p-ethylphenyl isocyanate, the dichlorophenyl isocyanates, methyl 
isocyanate, butyl isocyanate, n-propyl isocyanate, octadecyl isocyanate, 
3,5,5-trimethyl-1-isocyanato-3-isocyanatomethylcyclohexane, 
di(2-isocyanatoethyl)-bicyclo (2.2.1)-hept-5-ene-2,3-dicarboxylate, 
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane 
diisocyanate, dianisidine, diisocyanate, tollidine diisocyanate, 
hexamethylene diisocyanate, the m- and p-xylylene diisocyanate, 
tetramethylene diisocyanate, dicyclohexyl-4,4'-methane diisocyanate, 
cyclohexane-1,4-diisocyanate, 1,5-naphthylene diisocyanate, 
4,4'-diisocyanate diphenyl ether, 2,4,6-triisocyanate toluene, 
4,4',4"-triisocyanatotriphenyl methane, diphenylene-4,4'-diisocyanate, the 
polymethylene polyphenylisocyanates, as well as any of the other organic 
isocyanates known to the average skilled chemist. 
It is customary to use any of the known urethane-forming reaction catalysts 
during the isocyanate reaction with the polyol. These are well known and 
any of the catalysts can be used. Illustrative thereof are dibutyltin 
dilaurate, stannous octoate, triethylenediamine, triethylamine, the known 
salt catalysts, and the like. The catalysts are generaly employed at a 
concentration of from about 0.1 to 1 weight percent based on the weight of 
the reaction mixture. 
The amount of isocyanate used is an amount to provide sufficient isocyanato 
equivalents to react with the reactive hydroxyl equivalents on the adduct. 
It is customary to use a slight excess to assure complete reaction. As 
previously indicated when a monoisocyanate is employed the novel 
N-(substituted carbamoyloxy)alkanoyloxalkyl (or aryl) acrylate ester of 
formula I is monofunctional in respect to acrylyl functionality and when a 
polyisocyanate is used such formula I ester is polyfunctional in respect 
to acrylyl functionality. The term "acrylyl" includes acrylyl, methacrylyl 
and cyanoacrylyl groups. 
The second step of the reaction is generally carried out by slowly adding 
the isocyanate to the adduct obtained in the first step of the reaction at 
a temperature of from 20.degree. to 90.degree. C., preferably from about 
25.degree. to 75.degree. C., and most preferably from about 40.degree. to 
55.degree. C. During this addition the mixture is stirred; thereafter 
stirring is continued at the selected reaction temperature for a short 
period of time to assure completion of reaction. The residual product is 
then vacuum stripped to remove volatiles and, if necessary, filtered to 
remove any trace quantities of solid particles. The N-(substituted 
carbamoyloxy)alkanoyloxyalkyl acrylate ester produced corresponding to 
formula I can be used per se or in formulated compositions. 
In producing formulated compositions the novel compounds of this invention 
are compounded with activators or catalysts, photoinitiators or 
photosensitizers, pigments or colorants, solvents, other reactive 
components, etc. The formulators skilled in the art of inks, coatings and 
adhesives are fully familiar with the requirements in their respective 
fields and the components used. Such components can be formulated with the 
novel compounds of this invention by the known and conventional procedures 
and in the accepted concentrations. 
Thus, when cure is to be accomplished by thermal means a conventional free 
radical catalyst or activator is used; when the cure is to be achieved by 
particulate radiation such as electron beam radiation, an activator is 
usually not required; when cure is to be effected by light radiation such 
as ultraviolet light, a photosensitizer or photoinitiator, with optionally 
an activator therefor, is needed to render the cure process commercially 
acceptable. Coating, ink or adhesive compositions can contain from 1 to 
100 weight percent, preferably from 5 to 75 weight percent and most 
preferably from 5 to 50 weight percent of the novel compounds of this 
invention as the reactive component thereof. The specific identities of 
the other components referred to in this and the preceding paragraph are 
well known to those skilled in the art and require no further elaboration 
herein to enable such person to produce the formulations.

The following examples serve to further illustrate the invention. 
EXAMPLE 1 
Step 1--Production of Hydroxyethyl Acrylate: epsilon-Caprolactone Adduct 
A rector was charged with 241.6 g of hydroxyethyl acrylate and 2 g of boron 
trifluoride etherate and the contents were heated to 65.degree. C. Over a 
20-minute period 456 g of epsilon-caprolactone were added; during the 
addition the mixture was stirred and cooled to maintain a temperature of 
55.degree. to 60.degree. C. After all of the lactone had been added the 
mixture was stirred at 69.degree. to 72.degree. C. for one hour. Fourteen 
grams of magnesium silicate was added and stirring continued for 2 hours 
at 90.degree. C. The liquid was filtered hot and 652 g of the adduct was 
recovered. A repeat run had an hydroxyl number of 128 mg KOH/g, a 
viscosity of 282 cks at 38.degree. C. and a color of 4.5 Gradner Units. On 
standing several days both became slushy mixtures. 
Step 2--Production of (N-Methylcarbamoyloxy)(di-hexanoyloxy)ethyl acrylate 
To the 652 g adduct of Step 1 there was added 0.5 g of dibutyltin dilaurate 
and the temperature was adjusted to 45.degree. C. Over a 30 minute period 
106 grams of methyl isocyanate were added at 45.degree. to 48.degree. C. 
After addition was complete the mixture was stirred for 3 hours at 
45.degree. to 48.degree. C., and then stripped of volatiles for one hour 
at 3 to 5 mm. Hg pressure. There was obtained 738 grams of liquid (Monomer 
I) having a color of 3.5 Gardner Units and the average formula: 
EQU CH.sub.3 NHCO(OC.sub.5 H.sub.10 CO).sub.2 OC.sub.2 H.sub.4 
OOCCH.dbd.CH.sub.2 
The repeat run referred to in Step 1 was reacted in the same manner and 
produced a liquid (Monomer II) product having a viscosity of 652 cks at 
38.degree. (measured after standing one month at room temperatue) and a 
color of 5 Gardner Units. On further standing at room temperature both 
became slushy. 
Reaction of the adduct of Step 1 with tolylene diisocyanate produces a 
product having the average formula: 
##STR4## 
EXAMPLE 2 
Step I 
In a manner similar to that described in Example 1, 483.2 g of 
2-hydroxyethyl acrylate was reacted with 456 g of epsilon-caprolactone 
using 4 g of boron trifluoride etherate as catalyst. After neutralization 
and filtration there was recovered 917 g of liquid adduct, which remained 
liquid upon prolonged storage at ambient room temperature, having an 
hydroxyl number of 240 mg KOH/g, a viscosity of 35.3 cks at 38.degree. C. 
and a color of 3.5 Gardner Units; its average formula was: 
EQU HOC.sub.5 H.sub.10 COOC.sub.2 H.sub.4 OOCH.dbd.CH.sub.2 
In a similar manner the adduct is produced using 2-hydroxypropyl 
methacrylate or 4-hydroxycyclohexyl acrylate in place of the 
2-hydroxyethyl acrylate. 
Step 2 
In a manner similar to that described in Example 1, 458 g of the adduct 
shown above was reacted with 113.9 g of methyl isocyanate at 45.degree. to 
50.degree. C. using 0.35 g of dibutyltin dilaurate catalyst. After 
stripping in vacuo there was recovered 559 g of liquid (Monomer III) 
having a viscosity of 72 cks at 38.degree. C., a color of 4 Gardner Units 
and the average formula: 
EQU CH.sub.3 NHCOOC.sub.5 H.sub.10 COOC.sub.2 H.sub.4 OOCCH.dbd.CH.sub.2. 
EXAMPLE 3 
Step 1 
In a manner similar to that described in Example 1, 241.6 g of 
2-hydroxyethyl acrylate was reacted with 912 g of epsilon-caprolactone at 
60.degree. to 70.degree. C. using 2 g of boron trifluoride etherate. After 
neutralization with magnesium silicate there was recovered 1,120 g of a 
slushy adduct having an hydroxyl number of 105, a viscosity of 316 cks at 
38.degree. C., a color of 4 Gardner Units and an average of four 
--(OC.sub.5 H.sub.10 CO)-- units. 
In a similar manner the adduct is produced using 2-hydroxypropyl acrylate 
in place of the 2-hydroxyethyl acrylate. 
Step 2 
In a manner similar to that described in Example 1, 560 g of the adduct 
produced above was reacted with 55.3 g of methyl isocyanate at 45.degree. 
to 50.degree. C. using 0.4 g of dibutyltin dilaurate catalyst. After 
stripping in vacuo there was obtained a liquid (Monomer IV) having a 
viscosity of 450 cks at 38.degree. c., a color of 4.5 Gardner Units and an 
average formula of: 
EQU CH.sub.3 NHCO(OC.sub.5 H.sub.10 CO).sub.4 OC.sub.2 H.sub.4 
OOCCH.dbd.CH.sub.2 
Upon prolonged standing at ambient room temperature it became slushy. 
Monomers I to IV were evaluated as components in radiation curable coating 
compositions and comparred to compositions that did not contain these 
reactive monomers but contained an equal weight amount of known reactive 
monomers, namely 2-ethylhexyl acrylate (2-EHA) and 
(N-methylcarbamoyloxy)ethyl acrylate (MCEA). The radiation curable 
compositions were produced containing 30 weight percent of Monomer I to 
IV, 2-EHA or MCEA as a reactive diluent monomer and 70 weight percent of a 
reactive oligomer (Oligomer A) produced in the reactive diluent monomer. 
Oligomer A was the reaction product of a poly-epsilon-caprolactone diol 
having an average molecular weight of 530, isophorone diisocyanate and 
2-hydroxyethyl acrylate. 
A radiation curable composition was produced by charging 125 g of 
isophorone diisocyanate, 150 g of Monomer II as diluent and 0.4 g of 
dibutyltin dilaurate to a reactor and heating the mixture of 40.degree. C. 
Over a 15 minute period 153 g of poly-epsilon-caprolactone (Av. M.W. 530) 
was added followed by 69 g of 2-hydroxyethyl acrylate over a similar 
period. The mixture was then stirred overnight at 42.degree. C. to 
complete the reaction. There was obtained a 30/70 by weight mixture of 
Monomer II and the oligomer produced by the reaction of the 
polycaprolactone, isophorone diisocyanate and 2-hydroxyethyl acrylate to 
which was added one weight percent of di(secbutoxy)acetophenone 
photoinitiator (Coating II). 
In a similar manner, coating compositions were produced with Monomers I, 
III and IV of the above examples as the diluents and compared with two 
control compositions in which the diluents used were heretofore available 
reactive compounds, namely 2-EHA and MCEA. Quantities reacted were the 
same as those recited above. 
The individual coating compositions were evaluated by application to a 
steel plate using a wire-wound rod and curing by exposure to ultraviolet 
light radiation in a nitrogen-inerted system. The cured films were from 3 
to 5 mils thick and their properties were determined using an Instron 
Tensile Tester in accord with ASTM-D-638. 
The production and evaluation details of the clear films produced are shown 
in Table I. 
TABLE I 
______________________________________ 
Reactive Tensile 
Monomer Coating Strength Elongation 
Charged Produced psi % 
______________________________________ 
I I 1600 69 
II II 1700 68 
III III 1700 66 
IV IV 920 56 
2-EHA Control A 260 33 
MCEA Control B 3300 44 
______________________________________ 
The results show that Coatings I to IV, containing Monomers I to IV, 
exhibit, on an overall balance of properties tested, improved properties 
over Control A. Further, the monomers of this invention and compositions 
containing them showed lower volatility and less odor than were observed 
with 2-EHA and MCEA.