Diluent for UV and EB curable resins

Acryloylmorpholine and/or methacryloylmorpholine useful as a reactive diluent for UV and EB curable resin compositions, which has low skin irritation, a little odor, low volatility, low weight loss and high workability and which provides, without imparing work environment, UV and EB curable compositions having a high curing rate and capable of forming films of high hardness with small deformation.

BACKGROUND OF THE INVENTION 
The present invention relates to a reactive diluent for ultraviolet and 
electron beam curable resins. 
In recent years, there has been actively forwarded a development of 
solventless resin compositions curable by radiation of ultraviolet rays or 
electron beams in view of environmental protection, labor saving and 
energy saving. In general, these UV or EB radiation curable resin 
compositions are composed mainly of a photopolymerizable prepolymer and a 
photopolymerizable vinyl monomer copolymerizable with the prepolymer. The 
UV curable resin compositions further contain a photoinitiator as an 
essential component. 
The photopolymerizable prepolymers can further polymerize by radiation of 
ultraviolet rays or electron beams and form a framework of cured polymers. 
The prepolymer is also called a photopolymerizable unsaturated polymer or 
a photopolymerizable oligomer. In accordance with the structure of 
molecule constituting the framework, there are used, for instance, 
oligomers having acryloyl or methacryloyl group at the polymer end, such 
as polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether 
acrylate, oligoacrylate, alkyd acrylate and polyol acrylate. 
The photopolymerizable vinyl monomers serve, in cooperation with the 
prepolymer, to improve the functions of curable resin compositions or the 
applicability or suitability to uses of cured products. For instance, they 
are used for the purpose of decreasing the viscosity of the composition to 
thereby improve the coatability to substrates, imparting the flexibility 
to cured products, or improving the adhesion to substrates. Also, the 
curable composition itself can be made solventless by utilizing the 
dissolving power and polymerizability of the monomers. Since the 
photopolymerizable monomers are required to have a good copolymerizability 
with prepolymers and a high curing rate, polyfunctional or monofunctional 
acrylic monomers are usually used. 
Monofunctional monomers serve as a diluent for highly viscous prepolymers, 
thereby securing the workability of resin compositions in practical use. 
Moreover, the monomers themselves polymerize to form a part of the 
structure of cured products without going out from the system. Therefore, 
it is possible to formulate the curable resin compositions into 
solventless compositions, thus the monomers have an important meaning in 
providing UV or EB radiation curable resin compositions free from solvent 
pollution. In this sense, the photopolymerizable monomers are also called 
a reactive diluent. 
The reactive diluents are essential to have a large ability of lowering the 
viscosity of prepolymers from the viewpoint of the object of use. Also, it 
is desirable that the reactive diluents do not give out a bad smell or do 
not cause health disturbances such as dermatitis in handling them. 
In general, however, acrylic monomers have a strong skin irritation and the 
improvement has been demanded. It is disclosed in Japanese Unexamined 
Patent Publication (Tokkyo Kokai) No. 147024/1978 that the skin irritation 
of acrylic monomers is decreased by increasing the molecular weight of 
monomers. However, when the molecular weight is increased too large, the 
ability of lowering the viscosity of prepolymers is decreased, because the 
viscosity of the monomers themselves rises. Also, in cases, the 
compatibility with prepolymers is decreased. For such reasons, there has 
been strongly desired a development of a reactive diluent monomer having a 
high dissolving power, a high diluting effect, a low volatility, a low 
smelling property, a low skin irritation, and moreover having an excellent 
curing activity. 
SUMMARY OF THE INVENTION 
It has now been found that acryloylmorpholine and its derivative have 
characteristics as an ideal reactive diluent, that is to say, they have 
excellent characteristics such as good reducibility, high dissolving 
power, low volatility, low smelling property and low skin irritation which 
have been considered to be difficult to achieve them together, and 
moreover the curing activity is high. 
In accordance with the present invention, there is provided a reactive 
diluent for photopolymerizable prepolymers in ultraviolet or electron beam 
radiation curable resin compositions, which comprises a compound of the 
formula (1): 
##STR1## 
wherein R is hydrogen atom or methyl group. 
The reactive diluent of the present invention is used, in a UV or EB curing 
system where a photopolymerizable prepolymer is reacted with 
monofunctional and/or polyfunctional photopolymerizable monomers 
copolymerizable with the prepolymer, for dissolving or diluting the 
reaction system and for enabling a homogeneous reaction, if necessary, by 
using a photoinitiator and a sensitizer. Also, the reactive diluent itself 
reacts to form a part of cured products. 
Acryloylmorpholine used in the present invention is a known compound, for 
instance, as reported in "Polyacrylamides derives d'amides cyclyques" [J. 
Parrod and J. Elles, J. Polymer Sci., Vol 29, 411 (1985)], and is easily 
available for any persons. 
The greatest feature of the reactive diluent of the present invention is 
that the skin irritation which is the greatest defect of conventional 
reactive diluents, is very low and, therefore, the safety is very high. 
That is to say, the primary skin irritation index (PI value), which is an 
index showing the degree of skin irritation, of the compound of the above 
formula (1) is not more than 0.50 and is very low in comparison with other 
acrylate monomers as described after. In addition to a high safety, the 
reactive diluent of the invention also has excellent characteristics such 
as high dissolving power and reducibility for prepolymers, low smelling 
property, low volatility and high curing activity, and it is not too much 
to say that the reactive diluent of the invention is an ideal reactive 
diluent. These characteristics and the advantages of the reactive diluent 
of the invention will apparent from Examples and Comparative Examples 
described after. 
In another aspect, the present invention also provides a resin composition 
curable by radiation of ultraviolent rays or electron beams which 
comprises a photopolymerizable prepolymer and a compound of the formula: 
##STR2## 
wherein R is hydrogen atom or methyl group. The composition may further 
contain other known photopolymerizable monomers, a photoinitiator, a 
sensitizer, or known additives suitable for the purposes of the 
composition. 
DETAILED DESCRIPTION 
In the present invention, acryloylmorpholine and methacyloylmorpholine are 
used alone or in admixture thereof as a reactive diluent for UV and EB 
curable resin compositions. The reactive diluent of the invention may be 
used in combination with other known reactive diluents, namely known 
photopolymerizable monofunctional monomers. It is known that the 
additivity applies in the PI value. When acryloylmorpholine and/or 
methacryloylmorpholine are used in combination with other reactive 
diluents, it is preferable from the safety point of view to determine the 
amount of other reactive diluents so that the PI value of the mixture is 
not more than 2. For instance, when acryloylmorpholine whose PI value is 
0.50 is used in combination with nonylphenoxyethyl acrylate whose PI value 
is 4.3, it is preferable to use nonylphenoxyethyl acrylate in an amount of 
0.36 part per part of acryloylmorpholine. 
In order to compare the safety between acryloylmorpholine, 
methacryloylmorpholine and known reactive diluents, PI values thereof are 
shown in Table 1 together with the molecular weight. 
TABLE 1 
______________________________________ 
Molecular 
Monomer PI value weight 
______________________________________ 
Acryloylmorpholine 0.50 141 
Methacrylolmorpholine 
&lt;0.50 155 
Tetrahydrofurfuryl acrylate 
8.0 156 
Benzoyloxyethyl acrylate 
3.3 220 
2-Hydroxy-3-phenoxypropyl acrylate 
3.6 222 
______________________________________ 
As apparent from Table 1, the PI values of acryloylmorpholine and 
methacylolmorpholine is not more than 0.50 despite that the molecular 
weights are lower than known monofunctional monomers. It would be 
understood that acryloylmorpholine and methacryloylmorpholine are 
monofunctional monomers having a very high safety. 
The PI value can be measured by applying a compound to be tested to 
non-treated skin and scratched skin of a normal white rabbit weighing 2.0 
to 3.0 kg, according to a method as provided in 16 CFR .sctn.1500.42 
(Consumer Product Safety Commission in USA). The PI value is estimated in 
six ranks according to the following criteria. 
______________________________________ 
PI value Estimation 
______________________________________ 
0.00 to 0.03 No irritation 
0.04 to 0.99 Irritation barely perceptible 
1.00 to 1.99 Slight irritation 
2.00 to 2.99 Mild irritation 
3.00 to 5.99 Moderate irritation 
6.00 to 8.00 Severe irritation 
______________________________________ 
No problem occurs below slight irritation, but monofunctional monomers 
showing mild irritation must be used with special attention and the use of 
monofunctional monomer showing severe irritation has been avoided. 
Reactive diluents having a high safety, namely reactive diluents having a 
PI value of not more than 0.99 "irritation barely perceptible", have been 
demanded strongly more and more because of increasing interest in safety 
in recent years as well as performances of curable resin compositions and 
cured products. In this respect, the compound (I) is very useful as the 
reactive diluent. 
The reactive diluent of the present invention is applicable to known 
prepolymers. The kinds of prepolymers are not particularly limited so long 
as they are soluble in the compound (I) or mixtures of the compound (I) 
and other known reactive diluents. Examples of the prepolymers are, for 
instance, a polyester acrylate, a polyurethane acrylate, an epoxy 
acrylate, a polyether acrylate, an alkyd acrylate, a polyol acrylate, and 
the like. 
In the present invention, the curable resin composition may further contain 
a polyfunctional monomer in addition to the photopolymerizable prepolymer 
and the reactive diluent. The polyfunctional monomer causes a crosslinking 
reaction between molecular chains of the prepolymer and contributes to 
improvement in physical properties of cured products such as heat 
resistance. Known polyfunctional monomers can be used in the present 
invention without any restriction. Examples of the polyfunctional monomer 
are, for instance, diacrylates and dimethacrylates of glycols such as 
butylene glycol diacrylate and dimethacrylate, diethylene glycol 
diacrylate and dimethacrylate, hexanediol diacrylate and dimethacrylate, 
and neopentyl glycol diacrylate and dimethacrylate; triacrylates and 
trimethacrylates such as trimethylolpropane triacrylate and 
trimethacrylate; and the like. The polyfunctional monomer is used in an 
equal or less amount to the diluent, especially in an amount of one-half 
or less of the weight of the diluent. 
The amount of the reactive diluent to the prepolymer varies depending on 
the kind of prepolymer and use of the composition. In general, the 
reactive diluent is used in an amount of 5 to 50 % by weight based on the 
prepolymer. It is convenient to determine a suitable amount by setting up 
a measure on 10 to 30 % by weight. 
In case of preparing a UV curable resin composition, a photoinitiator is 
usually incorporated in the composition. Any of known photoinitiators can 
be used in the present invention. Examples of the photoinitiator are, for 
instance, a benzoin compound such as benzoin, benzoin methyl ether, 
benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether or 
.alpha.-methylbenzoin, a benzil compound such as benzil or benzil methyl 
ketal, benzophonone, dimethoxyphenyl acetophenone, 
4,4'-bis(dimethylamino)benzophenone, a sulfur compound such as 
thioxanthone or derivatives thereof, an azo compound such as an 
aryldiazonium salt, and the like. 
Sensitizers may also be used in the present invention in an arbitrary 
amount as conventionally used in UV radiation curable compositions. 
Examples of the sensitizer are, for instance, an amino compound such as 
dimethylaminoethanol, methyl N,N-dimethylaminoanthranilate or 
ethyldimethylaminobenzoic acid, an acrylic monomer having tertiary amino 
group such as N,N-dimethylaminoethyl acrylate and methacrylate or 
N,N-dimethylaminopropyl acrylamide and methacrylamide, and other known 
sensitizers. 
The UV and EB radiation curable resin compositions of the present invention 
may further contain a pigment, an inert organic polymer, a levelling 
agent, a thixotropic thickener, a thermal polymerization inhibitor, a 
solvent, and other additives, as occasion demands. 
The UV and EB curable compositions can be prepared, applied and cured in a 
usual manner. Any of known light sources for radiating ultraviolet rays 
can be used and they are suitably selected according to objects and uses. 
As the light sources, there are mentioned, for instance, light sources of 
arc lamp type, flash lamp type, laser type and electrodeless lamp type 
(microwave). Also, as electron beam accelerators, both the scanning type 
and the curtain type can be used. 
The present invention is more specifically dsecribed and explained by means 
of the following Examples, in which all % and parts are by weight unless 
otherwise noted. It is to be understood that the present invention is not 
limited to the Examples, and various changes and modifications may be made 
in the invention without departing from the spirit and scope thereof.

In the Examples, tests were made according to the following methods. 
(1) Pencil Hardness 
In order to examine the degree of curing of a curable resin composition, 
pencil hardness of a cured film was measured according to JIS K 5401 by 
using an electromotive pencil hardness tester (type C-221 made by 
Yoshimitsu Seiki Co., Ltd.) under conditions of a scratching load of 1 kg 
and a scratching speed of 30 mm/minute. 
(2) Viscosity 
The viscosity of a curable resin composition was measured by a Brookfield 
viscometer (unit: centipoise). 
EXAMPLES 1 TO 3 AND COMATIVE EXAMPLES 1 TO 3 
The dissolving power and reducing power of acryloylmorpholine were tested 
with respect to representative photopolymerizable prepolymers, namely a 
polyester acrylate (commercially available under the trade mark "ARONIX 
M-6200" made by Toagosei Chemical Industry Co., Ltd.), an epoxy acrylate 
(grade number C-3000 made by Somar Corporation) and a polyurethane 
acrylate (commercially available under the trade mark "Photomer 6008" made 
by San Nopco Limited). The odor of the mixture of acryloylmorpholine and 
the prepolymers was also estimated. 
For comparison, the same texts as above were made with respect to 
2-ethylhexyl acrylate conventionally used as a reactive diluent. 
The results are shown in Table 2. 
In Table 2, the state of the mixture of prepolymer and diluent monomer was 
estimated by the naked eye according to the following criteria. 
______________________________________ 
State of composition 
.circleincircle. 
Transparent 
.circle. Slightly cloudy 
X Cloudy 
______________________________________ 
Also, the mixture of prepolymer and diluent monomer was smelled at a 
temperature between room temperature and 50.degree. C. and estimated 
according to the following criteria. 
______________________________________ 
Odor .circleincircle. 
Odorless 
.circle. Slight odor 
X Very irritating odor 
______________________________________ 
TABLE 2 
__________________________________________________________________________ 
Mixing 
Properties of mixture 
Viscosity 
Prepolymer Diluent 
ratio A/B 
Visco- 
State of 
measuring 
(A) monomer (B) 
(by weight) 
sity (cps) 
mixture 
Odor 
temperature 
__________________________________________________________________________ 
Ex. 1 10:0 2120 .circleincircle. 
.circle. -.circleincircle. 
Polyester acrylate 
Acryloyl- 
9:1 800 .circleincircle. 
.circle. 
(ARONIX M-6200) 
morpholine 
8:2 373 .circleincircle. 
.circle. 
30.degree. C. 
7:3 146 .circleincircle. 
.circle. 
Ex. 2 10:0 30450 
.circleincircle. 
.circle. -.circleincircle. 
Epoxy acrylate 
Acryloyl- 
9:1 9600 .circleincircle. 
.circle. 
(C-3000) morpholine 
8:2 2900 .circleincircle. 
.circle. 
50.degree. C. 
7:3 830 .circleincircle. 
.circle. 
6:4 400 .circleincircle. 
.circle. 
Ex. 3 10:0 25000 
.circleincircle. 
.circle. -.circleincircle. 
Polyurethane 
acrylate Acrylyol- 
9:1 11900 
.circleincircle. 
.circle. 
(Photomer 6008) 
morpholine 
8:2 4400 .circleincircle. 
.circle. 
50.degree. C. 
7:3 1460 .circleincircle. 
.circle. 
6:4 560 .circleincircle. 
.circle. 
Com. 9:1 384 .circleincircle. 
X 
Ex. 1 
Polyester acrylate 
2-Ethylhexyl 
8:2 134 .circle. 
X 30.degree. C. 
(ARONIX M-6200) 
acrylate 
7:3 77 X X 
Com. 9:1 4750 .circleincircle. 
X 
Ex. 2 
Epoxy acrylate 
2-Ethylhexyl 
8:2 980 .circleincircle. 
X 50.degree. C. 
(C-3000) acrylate 
7:3 100 .circleincircle. 
X 
6:4 66 .circleincircle. 
X 
Com. 9:1 4400 .circleincircle. 
X 
Ex. 3 
Polyurethane 
2-Ethylhexyl 
8:2 1760 .circle. 
X 50.degree. C. 
acrylate acrylate 
7:3 430 .circle. 
X 
(Photomer 6008) 6:4 138 .circle. 
X 
__________________________________________________________________________ 
As apparent from Table 2, acryloylmorpholine has excellent properties as a 
diluent such that the dissolving power and effect of decreasing viscosity 
are excellent irrespective of the kinds of prepolymers such as polyester 
acrylate, epoxy acrylate and polyurethane acrylate, and the obtained 
diluted solutions are in a good state and scarcely give smell. 
At first view, acryloylmorpholine looks inferior in viscosity reducing 
effect to 2-ethylhexyl acrylate. However, it is sufficient for practical 
use that the viscosity of a diluted solution is below 2000-3000 cps. 
Therefore, as shown in Table 2, the viscosity of prepolymers can be 
sufficiently reduced to the desired viscosity by adding at least 10-30 % 
by weight of acryloylmorpholine based on the prepolymers, and there is no 
problem in practical use. 
EXAMPLES 4 TO 6 AND COMATIVE EXAMPLES 4 TO 6 
In order to examine the photocure activity of acryloylmorpholine as a 
reactive diluent for ultraviolet curable resins, ultraviolet curable 
compositions as shown in Table 3 were prepared by adding 
acryloylmorpholine or 2-ethylhexyl acrylate as a reactive diluent, a 
difunctional acrylic monomer, a photoinitiator and a sensitizer to each of 
a polyester acrylate, an epoxy acrylate and a polyurethane acrylate which 
were representative prepolymers. 
Each of the compositions was applied in about 50 .mu.m thick to an aluminum 
plate by an automatic coater (type PI-1210 made by Tester Sangyo Co., 
Ltd.), and ultraviolet rays were irradiated to the coated surface for a 
prescribed period by using a high pressure mercury lamp radiation 
apparatus ("Jet Printer JP-2000" made by ORC Manufacturing Co., Ltd.) 
(lamp: 2 kW). The pencil hardness and surface tackiness of the cured films 
were examined. 
The results are shown in Table 4. 
TABLE 3 
__________________________________________________________________________ 
Reactive 
UV curable composition 
Prepolymer 
diluent 
Function Compound Content (%) 
__________________________________________________________________________ 
Ex. 4 Prepolymer ARONIX M-6200 
60 
Difunctional acrylate 
KAYARAD-HDDA*.sup.1 
20 
Polyester 
Acryloyl- 
Reactive diluent 
Acryloylmorpholine 
15 
acrylate 
morpholine 
Photoinitiator 
IRGACURE 184*.sup.2 
3 
Sensitizer DMAEA*.sup.3 
2 
Com. Prepolymer ARONIX M-6200 
60 
Ex. 4 Difunctional acrylate 
KAYARAD-HDDA 
20 
Polyester 
2-Ethylhexyl 
Reactive diluent 
2-Ethylhexyl acrylate 
15 
acrylate 
acrylate 
Photoinitiator 
IRGACURE 184 
3 
Sensitizer DMAEA 2 
Ex. 5 Prepolymer C-3000 60 
Difunctional acrylate 
KAYARAD-HDDA 
20 
Epoxy Acryloyl- 
Reactive diluent 
Acryloylmorpholine 
15 
acrylate 
morpholine 
Photoinitiator 
IRGACURE 184 
3 
Sensitizer DMAEA 2 
Com. Prepolymer ARONIX M-6200 
60 
Ex. 5 Difunctional acrylate 
KAYARAD-HDDA 
20 
Epoxy 2-Ethylhexyl 
Reactive diluent 
2-Ethylhexyl acrylate 
15 
acrylate 
acrylate 
Photoinitiator 
IRGACURE 184 
3 
Sensitizer DMAEA 2 
Ex. 6 Prepolymer Photomer 6008 
60 
Difunctional acrylate 
KAYARAD-HDDA 
20 
Polyure- 
Acryloyl- 
Reactive diluent 
Acryloylmorpholine 
15 
thane morpholine 
Photoinitiator 
IRGACURE 184 
3 
acrylate Sensitizer DMAEA 2 
Com. Prepolymer Photomer 6008 
60 
Ex. 6 Difunctional acrylate 
KAYARAD-HDDA 
20 
Polyure- 
2-Ethylhexyl 
Reactive diluent 
2-Ethylhexyl acrylate 
15 
thane acrylate 
Photoinitiator 
IRGACURE 184 
3 
acrylate Sensitizer DMAEA 2 
__________________________________________________________________________ 
(Notes) 
*.sup.1 KAYARADHDDA: Hexanediol diacrylate (product of Nippon Kayaku Co., 
Ltd.) 
*.sup.2 IRGACURE 184: Benzyl derivative photoinitiator (product of Ciba 
Geigy Ltd.) 
*.sup.3 DMAEA: N,N--dimethylaminoethyl acrylate (product of Kohjin Co., 
Ltd.) 
TABLE 4 
__________________________________________________________________________ 
Properties of cured film 
Properties of composition 
UV radiation 
Pencil 
State Odor time (min.) 
hardness 
Tackiness 
Appearance 
__________________________________________________________________________ 
Ex. 4 1 -- .DELTA. 
-- 
.circleincircle. 
.circle. 
3 -- .circle. 
.circle. 
5 4H .circleincircle. 
.circle. 
Com. 1 -- X -- 
Ex. 4 
.circleincircle. 
X 3 -- .DELTA. 
-- 
5 F .DELTA.- .circle. 
X 
Ex. 5 1 -- .DELTA. 
-- 
.circleincircle. 
.circle. 
3 3H .circle. 
.circleincircle. 
5 4H .circleincircle. 
.circleincircle. 
Com. 1 -- X -- 
Ex. 5 
.circleincircle. 
X 3 -- .DELTA. 
-- 
5 2H .DELTA.- .circle. 
.circleincircle. 
Ex. 6 1 -- .DELTA. 
-- 
.circleincircle. 
.circle. 
3 -- .DELTA.- .circle. 
-- 
7 3H .circleincircle. 
.circleincircle. 
Com. 1 -- X -- 
Ex. 6 
.circle. 
X 3 -- X-.DELTA. 
-- 
7 2H .circle. 
.circle. 
__________________________________________________________________________ 
In Table 4, the tackiness of the cured film was observed by touching the 
film with finger and estimated according to the following criteria. 
______________________________________ 
Tackiness .circleincircle. 
Not sticky 
.circle. Slightly sticky 
.DELTA. Fairly sticky 
X Completely wet 
______________________________________ 
Also, the surface appearance of the cured film was estimated by the naked 
eye according to the following criteria. 
______________________________________ 
Appearance .circleincircle. 
Very smooth 
.circle. Few blistering 
X Dense blistering 
______________________________________ 
As apparent from Table 4, acryloylmorpholine has the advantages that the 
cure rate is very fast and it has an excellent curing activity, and also 
it provides cured films having a smooth surface and a high hardness, to 
say nothing that it has excellent abilities of dissolving prepolymers and 
of reducing the viscosity of prepolymers and a low PI value, namely a high 
safety, as stated before. It would be understood that acryloylmorpholine 
is very useful as a reactive diluent for UV radiation curable 
compositions. 
In order to estimate the volatility of reactive diluent which is often 
called into question in practical use, the weight loss of 
acryloylmorpholine and conventional reactive diluents was measured at 
60.degree. C. 
The results are shown in Table 5. 
TABLE 5 
______________________________________ 
Weight loss at 60.degree. C. (%) 
After After After After 
Monomer 1 hr. 2 hrs. 3 hrs. 7 hrs. 
______________________________________ 
Acryloylmorpholine 
0.2 0.9 1.4 2.6 
2-Ethylhexyl acrylate 
3.6 7.1 10.6 17.2 
N-Vinylpyrrolidone 
2.6 5.2 8.0 12.8 
Benzyl acrylate 
15.0 20.0 28.0 -- 
______________________________________ 
From Table 5, it would be understood that the volatility of 
acryloylmorpholine is very low as compared with conventional reactive 
diluents. This fact means that acryloylmorpholine is also advantageous in 
quality stability of cured films and safety. 
EXAMPLE 7 
The same ultraviolet radiation curable composition as in Example 4 was 
prepared except that methacyloylmorpholine was used instead of 
acryloylmorpholine. The composition was completely transparent and 
scarcely gave an odor. 
The composition was applied to an aluminium plate and cured in the same 
manner as in Example 4. The film cured by radiation of ultraviolet rays 
for 5 minutes was slightly sticky, but the film radiated for 7 minutes was 
completely cured and it had no stickiness and a pencil hardness of 4H and 
5H. 
EXAMPLES 8 AND 9 AND COMATIVE EXAMPLE 7 
In order to examine the curing activity of acryloylmorpholine as a reactive 
diluent for electron beam radiation curable compositions, electron beam 
curable compositions were prepared by adding a difunctional acrylic 
monomer and a reactive diluent to a polyester acrylate or epoxy acrylate 
prepolymer. 
Each of the compositions was applied in about 65 .mu.m thick to an aluminum 
plate by an automatic coater (type PI-1210 made by Tester Sangyo Co., 
Ltd.), and irradiated with electron beams by an electron beam radiation 
apparatus ("Unitron 200/2000" made by Ushio Inc.) (applied voltage: 200 
keV, exposure rate: 0.75 Mrad/pulse, dose: 0.75 to 3 Mrad). The state of 
cure of the cured films was examined. 
The results are shown in Table 6. 
TABLE 6 
__________________________________________________________________________ 
EB curable composition Property of cured film 
Amount 
Dose 
Function Compound (part) 
(Mrad) 
State of cure 
__________________________________________________________________________ 
Ex. 7 
Prepolymer Polyester acrylate ARONIX M-600 
60 0.75 
slightly sticky 
Difunctional monomer 
KAYARAD-HDDA 20 1.5 completely cured 
Reactive diluent 
Acryloylmorpholine 
15 3.0 completely cured 
Ex. 8 
Prepolymer Epoxy acrylate C-3000 
60 0.75 
slightly sticky 
Difunctional monomer 
KAYARAD-HDDA 20 1.5 completely cured 
Reactive diluent 
Acryloylmorpholine 
15 3.0 completely cured 
Com. 
Prepolymer Polyester acrylate ARONIX M-600 
60 0.75 
sticky 
Ex. 7 
Difunctional monomer 
KAYARAD-HDDA 20 1.5 slightly sticky 
Reactive diluent 
4-Vinylpyrrolidone 
15 3.0 completely cured 
__________________________________________________________________________ 
As apparent from Table 6, EB radiation curable compositions containing 
acryloylmorpholine has a very high curing rate. It would be understood 
that acryloylmorpholine is excellent in curing activity and is very useful 
as a reactive diluent for electron beam radiation curable compositions. 
In addition to the ingredients used in the Examples, other ingredients can 
be used in the Examples as set forth in the specification to obtain 
substantially the same results.