Note: Descriptions are shown in the official language in which they were submitted.
~ 7 10538
BACKGROU~D OF THE INVENT'ION
1. F'ield of the Invention
This invention relates to a radiation curable
composition produced by the reaction of poly (alkyleneoxy)
polyol or polyester pol~ol, organic diisocyanate, hydroxy-
alkyl acr~late, at a temperature`of from about 30C to
about 80C, wherein ~or each hydroxy equivalent in the
polyol, 2.5 to about 8.0 equivalents of organic diisocyanate
and 1.5 to about 6.0 equivalents of hydroxyalkyl acrylate
is reacted.
2. Description of `the'Prior Art
Increasingly tough attitudes and restrictions
regarding coating effluents allowed to escape from
finishing ~actories into the atmosphere, the current
trend toward high-speed processing, the increasing use of
heat-sensitive substrates, the shortage o space and the
high cost and ~uestionable availaLbility o energy have
~; combined ~o prompt considerable ef~orts to develop one-
hu~dred percent convertible, radiation-curable ink and
coatings systems. In compositions of this type, the ;~ `
diluents are "reactive solvents", i.e., fluid monomers
.
~thae ~ndergo reaction to become incorporated into the
cured film. The "cure" or polymerization of these systems ~ ~ -
is conveniently initiated by exposure of the applied ink or
coating to electron radiation or to ultraviolet light.
~lthough a variety o monomer types can be and
have been used, best results are obtained with acrylate
systems. Thè acrylate`inks/coatings are particularly '
--2--
~ ..
.
~ 3 ~ 10538
outstanding in that they provide ~ood response to radiation,
i.e., can be polymerized with a minimal amount of radiation.
A particularly important part of a radiation-curable
acrylate system is ~he oligomer or prepolymer. This low
molecular weight material normal~y has one or more acryla~e
groups per mole, and provides crosslink density (and
therefore chemical and physical properties) to the cured
product.
Since these systems are primarily acrylates,
it is no~ surprising that cured film propertie~ (with
allowances for molecular welght and crosslink density dif-
ferences) are comparable to the properties of conventional
acrylic resins. However, for many applications where
radiation-curing would offer process advantages, coatings/
inks with b~tter properties than those normally associated
with conventional acrylics are desired or even required.
For these areas, acrylated urethane oligomers o~ the type
described in U.S. 3,700,64~ were developed. These
materials provide measurably better film properties
particu~arly tensile strength, elongation, abrasion
resistance and resistance to chemicals and stains.
The oligomers normally used in formulations o~
this type are viscous materials with the result that by
the time the system has been diluted to application
viscosity ~normally 20-40 per cent oligomer), the oligomer
has been reduced to the rank of a minor component, and
the "urethane-like'l properties are measurably diminished
In addition, the high viscosity of the oligomers
makes it very di~icult to prepare the materlals consistently
- 10538
~3~7
without gelling (prematurely polymerizing) the product.
Also, even after the material has been prepared, it is
difficultly permeable by oxygen (air) and therefore has
poor stability (short sheIf life) and is difficult to
handle.
SUMMARY OF THE INVENTION
It has now been found that radiation curable
compositions produced by the reaction of poly(alkyleneoxy)
polyol or polyester polyol, organic diisocyanate and
hydroxyalkyl acrylate, at a temperature of from 30
- to about 80C wherein for each hydroxy
equivalent in the polyol, 2.5 to about 8.0 equivalents of
organic diisocyanate and 1.5 to about 6.0 equivalents of
hydroxyalkyl acrylate is reacted, provide coating com-
positions of increased toughness. Also, formulations - ~-
based on the poly(alkyleneoxy)polyols provide unexpected
high gloss to conventional air drying inks, when applied
wet on wet and cured by radiation techniques.
The poly(alkyleneoxy~polyols which can be
employed herein are well known in the art, as set forth in
U.S. Patent 3,582,501, for example. These include linear
and ~ranched poly(alkyleneoxy)polyols ha~ing at least one
and preferably a plurality of ether linkages and con-
taining at least ~wb hydroxyl groups and being substan~ially
free from functional groups other than hydroxy. The poly-
(alkyleneoxy~poLyols which`are useful herein include the
polyethylene(glycols having average molecular weights o 200,
400 and 600 and the polypropylene glycols having average
molecular weights of 400 to 4,000. Polymers and copolymers
--4--
10538
~ 5~7
of polyoxyalkylene polyols are also adaptable in the
process of this invention as well as the block copolymers
of ethylene and propylene oxide. Among the copolymers of
polyoxyalkylene polyols, and particularly propylene oxide,
that deserve some special mention are the propylene oxide
adducts of ethylene glycol, glycerol, 1,2,6-hexanetriol,
trimethylolpropane, trimethlolethane, pentaerythritol,
sorbitol, tris ~ydroxyphenylpropane), triethanolamine,
triisopropanolamine, ethylenediamine, diethylenetriamine
and ethanolamine. Linear and branched copolyethers of
ethylene oxide and propylene oxide have also been found
to be useful. Preferred copolymers of propylene oxide and
ethylene oxide are those containing 10 percent ethylene
oxide in molecular weights o 50(), 2000, 3000 and 4000.
Further useful types o polyethers are block
copolymers prepared from propylene oxide and ethylene
oxide.
The poly(alkyleneoxy)polyols preferably contain
2-4 carbon atoms in the alkylene portion thereof.
The polyester polyols suitable for use herein
are known in the art and are readily prepared by reacting
at least two bifunctional ingredients; a glycol and a
dibasic acid. Representative polyester polyols include
those prepared from ethylene glycol and adipic acid;
propylene glycol and adipic acid;.ethylene glycol (80 mol
percent), propylene glycol (20 mol percent) and adipic
acid; ethylene glycol (80 mol percent), propylene glycol
1,2 (20 mol percent) and azelaic acid, ethylene glycol
(80 mol percen~), propylene glycol 1,2 (20 mol percent)
3.~L~;L~7 10 538
and azelaic acid; ethylene glycol (80 mol percent),
propylene glycol 1, 2 (20 mol percent) and sebacic acid;
ethylene glycol (80 mol percent), propylene glycol 1,2
(20 mol percent) and dilinoleic acid (20 mol percent);
adipic acid (80 mol percent), ethylene glycol (80 mol
percent), glycerine monoethyl ether (20 mol percent) and
adipic acid; ethylene glycol (80 mol percent), butylene
glycol 1,4 (20 mol percent) and adipic acid; ethylene
glycol (80 mol percent), propylene glycol 1,3 (20 mol
percent) and adipic acid; ethylene glycol (80 mol percent)j:
pentane dioL 1,4 (20 mol percent) and adipic acid; ethylene ~ .
glycol (80 mol percent), glycerine monoisopropyl ether (20
mol percent) and adipic acid; ethylene glycol ~80 mol per-
cent), propylene glycol 1,2 (20 mol percent)~and maleic acid
(from 3 to 6 mol percent) J adipic acid tfrom 97 to 94 mol
percent); ethylene glycol (80 mol percent), butylene glycol
1,4 (20 mol percent) and adipic acid; ethylene glycol (80
mol percent), die~hylene glycol (20 mol percen~) and
adipic acid; ethylene glycol (rom 90 to 10 mol percent),
` 20 propylene~gl~col 1,2 (from 10 to 90 mol percent) and
adipic acid; ethylene:glycol (from 90 to 10 mol percent) J
propylene glycol 1,2 (rom 10 to 90 mol percent) and
azelaic acid.
The preferred polyester polyols are prepared
from a glycol containing 2 to 4 carbon atoms ,
The organic dii~o~y~nates suitable for ~se
herein are known in the art and include the aliphatic and
aromatie diisocyanates. Many such compounds are known to
those`skilled in ~hè art and illustrative thereof one can
--6--
135~8
mention 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate~
isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate,
di(2-isocyanatoethyl)-bicyclo (2.2.1) hept-5-ene-2,3-
dicarboxylate, 3,5,5-triethyl-1-isocyanato-3-isocyanato-
methylcyclohexane, 1,6-hexamethylene diisocyana~e, m- and
p-xylene diisocyanate, cyclohexane-1,4-diisocyanate,
dicyclohexyl-4,4'-methane diisocyanate, tetramethylene
diisocyanate, cyclopentylene-1,3-diisocyanate, 1,3-
diisocyanate, l,4-xylylene diisocyanate, 1,5-naphthalene
diisocyanate, m-phenylene diisocyanate, p-phenylene'
diisocyana~e, hexamethylene diisocyanate,' 3,3'-dimethyl- .:
4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane
diisocyanate, 3,3'-dimethyLbiphen~lene diisocyanate, 4,4'-
biphenylene diisocyanate, 3,3'-dimethoxy 4,~'-dimethyl
4,4'-biphenylene diisocyanate,' durene'diisocyanate, 1-
` phenoxy-2,4-phenylene diisocyanate, 1-~ert-butyl-2,4-
phenylene diisocyanate, 2,~,4-trimet'hylhexamethylene
: diLsocyanate, and tha like. The foregoing list is ill-
ustrative only:and is not intended to cxclude any other
zo ~ useful organic diisocyanates known to those skilled in
the art, `~ ~ :
~: - : A catal~st may be'op:tio~all~ used.in t~e'present
reaction. This catalyst is well known to the ure~hane
chemLst and does not require more than a brie~ mention.
: The most common catalysts include triethylene diamine,
; morpholine, N-ethyl-morpholine,~ piperazine, triethanolamine,
triethylamine, N,N~N',N'-tetramethylbutane-1,3-diamine,
dibutyltin dilaurate,. stannous octoate, stannous laurate, '
dioctyltin diace~ate, lead octoate, stannous oleate)'
-7-
10538
stannous tallate, dibutyltin oxide, etc The catalysts
and the concentrations to b~ used are known to vary
depending upon the particular amine or tin catalyst employed.
However, these catalys~s are used in amounts of from 0.0001
to 0.0500 weight percent, preerably from O.OOOS to 0.0100
weight percen~,based on the weight of diisocyanate ~mployed.
The hydroxyalkyl acrylates which can be used
herein are well known as diluents in uncured, radiation
curable compositions. This component is characteriæed by
the following formula:
R 0
I 11'
CH2 = c-C-o~Rl~OH
wherein R is hydrogen or methyl, Rl is an alkyl or
alkoxy group of 2 to 4 carbon atoms, and n is an integer
ranging from 1 to 6. The preferred hydroxylalkyl acrylates
are 2-hydrox~ethyl acrylate and the hydroxypropyl acrylates.
The reaction of the present invention can be
carried out in the presence of a solvent to facilitate
stirring and as solvent one can use any conventional
solvent or an inter~ediate which is desirably present in
t~`subsequently formulated coating or ink but which does
not interfere with the reactîon at the present time.
These include allyl acrylate, n-amyl acrylate,
benzyl acrylate, hydroxyethyl acrylate, hydroxypropyl
acrylate, cyclohexyl acrylate, cyclopentyl acrylate,
2-et~oxyethyl acrylate, isoprop~l acrylate, n-lauryl
acrylate, nonyl acrylate, n-octadecyl acrylate, n-octyl
~3~ 10538
acrylate, 2-phenoxyethyl acrylate, 2-ethylhexyl acrylate,
N-methyl(2-carbamoyloxy)ethyl acrylate, 1,6-hexanediol
diacrylate, neopentyl glycol diacrylate; tetraethyleneglycol
diacrylate, esterdîol-204-diacrylate, trimethylolpropane
triacrylate and the like, the compounds obtained when
methacrylyl groups are substituted for the acrylyl groups
of the foregoing compounds, N-vinyl pyrrolidone, etc. or
mixtures of these. The foregoing list is meant to be
illustrative only and is not meant to exclude any solvent
known to those skilled in the art as having utility in the
production of radiation curable compositions.
The radiation curable c~mpositions of the present
invention are produced by the reaction of poly(alkyleneoxy)
polyol or polyester polyol, organic di~socyanate, hyd~roxy-
alkyl acrylate in contact with catalyst, at a tempQrature
of from about 30C to about 80C and preferably from
about 45C, to about 60C, wherein for each hydroxy
equivalen~ in the polyol, 2.5 to about 8.0 equivalen~s of
organic diisocyanate and l.S to about 6.0 equivalents of
hydroxyalkyl aerylate is reacted.
Alternatively, the poly(alkyleneoxy)polyol or
polyester polyol and hydro~yalkyl acrylate can be added
either simultaneously or alternatively to organic diisocy-
anate, and optionally, catalyst andlor solvent, at a
temperat;ure of from about 30C to about 80C, and pre-
ferably from about 45C to about 60C, in the amounts of
reactants as previously defined.
The time required for the instant reaction will
vary depending upon the specific reactants employed, the
_g_
10538
temperature, the slze of the batch and other variables.
Those skilled in the'art are fully familiar with the effects
of these variables and will normally stop the reaction when
the residual isocyanate level drops below 0.5 per cent.
The coating compositions of this invention can
be cured by ionizing or non-ionizing radiation means in-
cluding, but not limited to, ul~raviolet and eIectron beam
radiation. These curing methods and the equipment that
can be used for them are well known to those skilled in
~he art. When the coating composition is~to be'cured by
non-ionizing radiation, the'presence of a photoinitiator
therein is desirable. Any of the known photoinitiators
can be used. Illustrative of suitable photoini~lators
one can mention 2,2-diethyoxyacetophenone, 2- or 3- or
4-bromoacetophenone, 3- or 4-allyla~etophenone,' 2-aceto-
naph~hone, benzaldehyde, benzoin, the alkyl benzoin e~hers,
benæophenone, benzoquinone, l-chloroanthraquinone~ p-diacetyl-
benzene, 9,lO dibromoa~thracene, 9,10-dich~oroanthracene,'
4,4-dichlorobenzophenone, thioxanthone, methylthioxanthone,
~, ~ ,~ , -trichloro para t-butyl acetophenone, 4-meth-
oxybenzophenone, 3-chloro-8-nonylxanthone, 3-iodo-7-m~th-~
` oxy~anthone, benzaldehyde, carbazole, 4-chloro-4'-benzyl-
benzophenoné, fluorene,' fluorenone, L,4-naph~hylphenylketone,
2,3-pentanedione, 2,2-di-sec-butoxy acetophenone,
dimethoxyphenyl acetophenone,propiophenone,' chIorothioxanthone,
xanthone and the like, or any mixtures of these.' The fore-
going list is meant to be illustrative only and is not meant
to exclude any suitable'photoinitia~ors known to those
skilled in the'ar~. Those'skilled in the'art will'kno~: the'
-10-
~- 10538
concentrations at which photoinitiators are efectively
employed and generally the concentration will not exceed
15 weight per cent of the radiation curable coating com-
position.
Those skilled in the art of photochemistry are
~ully aware that photoactivators can be used in combina-
tion with the aforementioned photoinia~ors and that
synergistic e~fects are sometimes achieved when such
combinations are u~ed. Photoactivators are ~eIl known in
the art and require no further description ~o make
known what they are and the concentrations at which they
are effective. Nonetheless, one can mention as illustrative
of suitable photoactivators, methylamine, tributylamine,
methyldiethanolamine, 2-aminoeth~lethanolamine, allylamine,
cyclohexylamine, cyclopentadienylamine, diphenylamine,
ditolylamine, trixylylamine, tribenzylamine, n-cyclohexy-
lethylenimine, plperidine, N-methylpiperazine, 2,2-dimethyl-
1,3-bis(3-N-morpholinyl) propionyloxypropan~, and the
like, or any combination of these. The radiation curable
coating compositions can also contain coloran~, fillers,
wetting agents, ~latting agents and other additives typically
present i~ coating compositions. These are well known and
require no further elaboration herein. Also ~nown are the
concentrations at whieh they are employed. While it is
preferred that the radiation curable coating compositions of
this invention be free of conventional solverlts, there can
be present in small amounts, prefera~ly less than 5 weight
per cent, a conventional soLvent, i desired.
The`concentrations of`the individual components
which make up the compositions of this invention can be
-11-
~L31.;23~ 10538
varied at the will of the practitioner within the
limits set forth above, provided that the total conc~n-
tration of acrylate-capped urethane, low
molecular weight polyfu~ctional acrylate and monofunctional
acrylate is at least 85 weight per cent, and preferably
at least 95 weight per cent, of the radiation curable
`coating composition.
The foregoing components are combined in any
manner suitable for achieving a unlform composition. When
the components have been mixed, they c~n be applied to a
substrate by means suitable for the appli~ation of
coatings, such as, for example, reverse roll coating,
direct roll coating, graw re, curtain coating, doctor
knife, spraying or brushing.
Example
The following examples are merely illus~rative
of the present invention and are not intended as a limit-
ation on the scope thereof.
Example` I
To a twelve liter four-neck flask fitted with
a stirrer, thermometer, condenser and dropping ~unnel was
charged 2232 grams of isophorone diisocyanate and 1.5
grams~of stannous octoate catalyst and 450 grams o
esterdiol-204-diacrylate. The mixture was heated (hot
water ~ath) to a temperature of 36~C at which time 4464
grams of polypropylene glycol (with average molecular
weight of 2000) was added over an hour and forty minu~e~.
The reactor was stirred or one hour at 40C. At the end
-12-
~7,
. ~ :
; ~ ~ ` :
10538
of this time 1848 grams o 2-hydroxyethyl acrylate was
charged into the flask over an hour and twenty ~inutes
while maintaining the tempexature below 50C. The
reactor was stirred for an hour and forty five minutes
at 48C prior to adding 1.0 gram of the monomethyl ether
of hydroquinone as stabilizer. The material was placed in
an oven at 50-55C until the res~dual isocyanate reached
a level of 0.1 per cent. The viscosity of this material
at ~5C was 22,800 centipoise (BrookfieId Model EVT using
~3 spindle).
Example 2
To a five liter four-neck flask fit~ed with a
stirrer, thermometer, condenser and dropping funnel was
charged 744 grams o~ isophorone di.isocyan~te ~nd 3 g~ams
of ~tannous oc~oate catalyst. The miæture was heated
(hot water bath) to a temperature of 50C at which time
1488 grams of polypropylen~ glycol (wit~ average molecular
weight of 2000) was added over forty three minutes. At
the end o~ this time 766 grams o~ 2-hydroxyethyl acrylate`
was charged into the flask over thirty minutes while
maintaining the temperature below 60C. The reaction
product was alIowed to set overnight at which time
the residual isocyanate leveI was nil.
E a~ple 3
To a five liter ~our-neck flask fitted with a
sti.rrer, thermometer, ~ondenser ~nd dropping ~unnel was
chàrged 942 gr~ms of isophorone diisocyanate and 3 0
-13-
~ ~ ~ 3 ~7 10538
grams of stannous octoate catalyst. The mixture was
heated (hot water bath) to a temperature of 50C at which
time 118~ grams of polypropylene glycol (with average
molecular weight of 2000) was added over seventy minutes,
while maintaining the temperature between 50-55C (ice
water bath). At the end of this time ~7~ grams of
2-hydroxyethyl acrylate was charged into the flask over
thirty minutes whiLe maintaining the temperature below
55C. The reaction product was allowed to cool overnight
and the following day the ree isocyanate leveI was 0.08
per cent.
E am~le 4
To a five liter four-neck flask fitted with a
stirrer, thermometer, condenser and dropping funnel was
charged L97 grams tolylene diisocyanate, 2.1 grams o~
sta~nou~ octoate c~talyst and 446 grams of N-methyl
carbamoyloxy ethyl acrylate. The mixture was heated
(hot water bath~ to 45C at which time 1400 grams poly-
propylene ~lycol (average molecular weight 4?00) was
added over fifty five minutes. At the end o~ this time
188 grams 2-hydroxyethyL acrylate was charged into the
~lask over a ~en minute period. The temperature dur~ng
the course af the reaction was kept below 55C by means
of a cold water bath. AnaLysis of the product showed
that the residual isocyanate level was nil.
To a ive liter four-neck flask fitted with a
stirrer, thermometer, condenQer and dropping funnel was
charged 320 græm~ tolylene diisocyanate, 2.4 grams stannous
-14
~ .....
~ .
~ ~L~ 1053~
octoate catalyst and 252 grams N-methyl carbamoyloxy-
ethyl acrylate. The mixture was heated to 34C at
which time 1600 grams polyprop~lene glycol (average
molecular weight 4000) was added over an hours time. The
mîxture was stirred for thirty minutes at which time 346
grams 2-hydroxyethyl acrylate ~ere added. The temperature
during the course of the reaction was kept below 45C.
Analysis of the product showed that the residual
isocyanate level was 0.06 per cent.
Example 6
To a five liter four-neck flask fitted with a
stirrer, thèrmometer, condenser and dropping funnel was
charged 240 grams tolylene diisocyanate, 2.3 grams stannous
octaate catalyst and 351 grams N-methyl carbamoyloxy
ethyl acrylate. The mixture was heated to 33C at which
time a ~lend consisting of 450 grams polypropylene glycol
(average molecular weight 2000) and 900 grams polypropylene
glycol (average molecular weight 4000) were added over
se~enty minutes. At the end of this time 323 ~rams
2-hydroxyethyl acrylate was charged into the flask over a
~ive minute period. The temperature during the course o~
the rea~tion was kept between 35-40C. Analysis of the
product showed that the residual isocyanate leveI was
0.08 per cent.
ExampIe 7
To a two liter four neck flask fitted with a
stirrer, thermometer, condenser and dropping funneI was
charged 342 grams tolylene diisocyan~te and 0.8 grams of
stannous oc~oate catalyst. The mixtu~e was heated to
~15-
~ ~3 5 ~ 1053~
46C at which time 129 grams of polypropylene oxide triol
(average molecular weig~t 253~ was added o~er a thirty
minute inter~al at a temperature of 58C. At the end
of this time 188 grams of trimethylol~ropane triacrylate
was added to the mixture, followed by addition of'282 grams
- 2-hydroxyethyl acrylate. The reactor was heId at 60C for
four hours and then allowed to cool overnight at room
temperature. Analysis of the product the'following day
show a residual free isocyanate:level of 0.14 per cent.
' Exam~le 8
To a two liter four neck flask fitted with a
stirrer, thermometer, condenser and dropping funnel was
charged 374 grams tolylene diisocyanate and 1.2 grams
stannous octoate catalyst. The mixture was heated to
45~C at which time 354 grams of a polyethylene oxide
triol (average molecular of`708) was added to the reactor
over a orty minute'inter~al. At the'end of thi~ time 124
grams 2-hydroxyethyl acrylate was fed to the~mixture'
followed by 263 grams of trimethylol~ropa~e trlacrylate
,,' 20 and another 200 grams 2-hydroxyethyl acrylate. The ~'
reaction mix was stirred at about 50C for an addiditonal'~
four hours and forty mi~utes at which time`it was
allowed to cool overnight. The following day analysis
showed that the residual isocyanate level was 0.17 per cent.
Exampl'e 9
To a fi~e liter four neck flask fitted with a
stixrer, thermometer, condenser and dropping unnel was
charged 586 grams isophorone diisocyanate and 2 grams of
stannous octoate catalyst. The mixture was heated to 45C
-16-
5 ~ 10538
at which time 904 grams of polypropylene glycol (average
molecular weight 1000) was added over fifty five minutes
while maintaining the temperature belo~ 55~C. At the
end of this timeJ509 grams 2-hydroxyethyl acrylate was
charged into the flask over a thirty minute interval.
-The reaction product was cooled and ~he residual isocyanate
was determine~ to be nil.
The products produced by the above
Examples were ormulated into coating compositions as set
forth in Tables I to III.
The following designations and abbreviations are
used in the Tables.
A: Product produced by Example :l
B: Product produced by Example 2
C: Product produced by Example '3
D: Product produced by Example 4
E: Product produced by Example 5
F: Product produced by Example 6
:G: Product produced by E~ample 7
: 20 H~ Product produced by Example 8
I: Product produced by Eæample 9
BZ: Benzophenone
- DBAP: Disec-butoxy acetophenone
DEAP: Die~hoxy acetophenone
DMPAP: Dimethoxyphenyl acetophenone
DRH-651 low viscosity epoxy acrylate supplied by
SheIl Chemical Co.
ED-204-DA: ester diol-204 diacr~late
. - .. . .
3~ 7 1 o 538
2-EHA: 2-ethylhexyl acrylate
HEA: 2-hydroxyethyl acrylate
MCEA: N-methyl(2-Carbamoyloxy)e~hyl acrylate
MDEOA: Methyl diethanol amine
MEK: methyl ethyl ketone
Slip Additive A:
Me3SiO ~ ~eSiO (Me2Si)20SiMe3
(I H2)3
(IC3H6)16.4
(fC2H4)22.5
OC4Hg
3.2
Slip Additive B:
Organo modi~ied silicone similar in
structure to slip additive A.
TMPTA: . Trimethylolpropane ~riacrylate
~: TABLE I
. . Per Cent.By ~e.ight.
- - -------- . --
:~ Com~onents .1 - ~: 2..... 3. 4. 5 . . 6
D ~0 SO -~ ~~~
E - - 60 50 - -
F - - - - 60 50
MCEA 21 41 39 49 26 41
DEAP
ED-204-DA 10 - 10 - 5
2-EHA 8 8 - - 8
-18-
.
-:
~~`~ 10538
35~7
The viscosity of the compositions of
Table I was measured using a Zahn cup. Each of the
coating compositions was applied to silicone release
paper using a No. 20 wire wound rod and cured to a
solid state by exposure in a nitrogen atmosphere to
medium pressure mercury arc lamps delivering a f`lux of
500 watts per square foot for 1 second. The cured
coatings, which were about 3 mils thick, were peeIed
from the release paper and subjected to tensil~ testing
~ASTM D-638)~ Tansile strength and elongation of the
cured coatings appear beIow. Elongation at break is
directly reIated to coating flexibility.
~ 1 2 ~ 4 5 6
2ahn Cup Viscosity, Seconds 182 124 286 232 185 108
Tensile Strength at Break, psi 600 200 1700 900 600 200
Elongatlon at Break, ~/O 65 105 75 115 100 100
TABLE II
~ Per Cent By Weight
Components 1 2 3 4 5 6 7
C 40 45 45
I - - - 45 50 40 50
E~-204-DA 30 30 35 35 35 25 30
MCEA ~ - lO 5.8
DEAP 0~9 0.~ 0,9 0.9 0.9 0.9 0.9
Slip Additive A 0.3 0.3 0.3 0.3 0.3 0.3 0.3
M~ 5 5 5 5 5 5 5
2-HEA 17.8 11.8 6.8 6.8 1.8 11.8 -
2-EHA 7 8 8 8 8 8 8
_, 9_
:~ ,
10538
~ 3 5 ~
The Brookfield RVT viscosi~y of each radiation curable
coating composition was measured using a No. 3 spindle.
The radiation curable coating compositions were then
applie~ to Bonderite No. 37 steel panels using a No. 3
wire wound rod. The compositions were cured by
exposure in a ni~rogen atmosphere to medium pressure
mercury arc lamps delivering a flux of 500 watts per
square foot for .4 seconds. As a measure of flexibility
of the coating compositions, reverse impact strengths were
measured by dropping a five pound rod having a round tip
onto the uncoated side of the substrate and recording the
dis~ance of drop required to crack the surface; the value
is then reported in inch-pounds.
1 2 3 4 5 ' 6 7
Brookield Viscosity,
cps 84 114 130 140 230 90 240
ReversP Impact,
inch pounds 150 150 150 150 lS0 150 150
TABLE III
Parts By Weight
~y~ 1 2 3 4
C 70 - _ _
~ 70 _ _
TMPTA 30 30
DBAP 2 2 2
MDE~A 3
~Z 2 - _ _
DMPAP - 3
Slip Additive B .5 .5 1.0 1.0
A - - 70 50
DRH-651 - - 30 50
-20-
~`- 10538
The Brookfield LVT viscosity of each radiation
curable coating composition was measured. The radiation
curable coating compositions were ~hen applied wet-on-wet
to paperboard,which co~tained a reshly applied conventional
air-drying black ink, using a Quick Peek Proofer. The
material was then cured by exposure in a nitrogen
atmosphere to medium pressure mercury arc lamps delivering
a flux of soa watts per square foot for 0.2 seconds. The
resulting cured coatings were then visually inspected for
hold out (coating absorption into the paperboard)J flow
(lack of irregularities of the coatings surface~ and ..
gloss.
1 2 3 4
Brookfield Viscosity, - - 775 715
centipoise
Hold Out Good Good Good Good
Flow Out Fair Fair Good Good "
Glo~s Level Good Good Good Good
,
