Note: Descriptions are shown in the official language in which they were submitted.
CA 02290430 2002-04-29
WO 9~~~2700 PCT/US98/10624
S
METHOD AND COMPOSITION'S FOR DECORATING GLASS
Technical Field
The invention is in the field of decorating vitreous articles with radiation
curable
inks. In particular, the invention relates to decoration of vitreous articles
such as glass,
with radiation curable inla which, to facilitate recycling, are capable of
being
chemically removed from the glass upon exposure to alkali for a specified
period of
time.
Back_t;round of the Invention
Commercial ceramic and glassware is often decorated by applying a pattern in
colored ink on the surface of the substrate with screen printing, offset
printing, or any
other direct application technique. The glass is then baked at high
temperatures to bond
the design or indicia to the glass surface. This process, sometimes referred
to as
applied ceramic labeling (ACL), exhibits certain drawbacks. Often, the ink
compositions contain heavy metals and volatile organic solvents (VOC's). Both
VOC's
and heavy metals are undesirable from the environmental point of view. Second,
ACL
requires high temperature ovens for the baking step, which results in
considerable
energy usage and an increased potential for worker injury due to the high
temperatures
3 0 at which the process operates. Moreover, the high temperature ovens are
expensive,
cumbersome pieces of equipment which require considerable floor space in
factories.
_~ The decoration of glass with ultraviolet (UV) radiation curable organic
pigmented
inks for the decoration of glass and ceramic ware is known in the art. Organic
inks
3 5 generally can be cured by exposure to radiation, such as ultraviolet ~
radiation, thus
obviating the need for high temperature baking. In addition, UV curable
organic inla
SUBSTITUTE SHEET (RULE 26)
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V~ ~l 98/52700 PCT/US98/10624
can be formulated to contain little or no VOC's or other nonaqueous solvents.
Organic
inks generally exhibit excellent adherence to glass.
In many countries, it is mandatory that beverages such as beer and soda, be
marketed in returnable glass bottles. After the beverage has been consumed,
the glass
bottles are returned to the beverage filler. They are then cleaned,
sterilized, refilled,
relabeled, then sold again. Decals and paper labels are most often used to
decorate
returnable beverage bottles. Both types of labels have many drawbacks. For
example,
both paper labels and decals are expensive. In addition, they are messy, and
can easily
come off upon exposure to water or other materials. In addition, many of the
adhesives
used in decals become sticky when subjected to the bottle cleaning process,
and cause
machines, drains, etc. to be gummed up.
There is a need for a method to decorate returnable beverage bottles that
provides excellent decorative effect. In addition, the method must be cost
competitive
when compared to paper labels and decals. At the same time the decorative
indicia
applied should be easily strippable from the glass container between fillings.
2 0 Summate of the Invention
The invention is directed to a method for decorating a vitreous article
comprising
the steps of:
a) applying to the vitreous article in a predetermined design a radiation
curable
ink composition which is (l) operable when cured to bond to the vitreous
article, and (ii)
2 5 strippable from the vitreous article upon exposure to alkali,
b) curing the ink on the vitreous article by exposing it to the radiation by
which
it is curable, thereby bonding the ink to the vitreous article.
The invention is also directed to a method for stripping decorative indicia
from a
3 0 vitreous article decorated with a radiation cured ink composition
containing free acid
groups which is (l) operable, when cured, to bond to the vitreous article, and
(ii)
strippable from the vitreous article upon exposure to alkali, comprising
contacting the
vitreous article with an aqueous alkaline solution containing 2-20 % by weight
alkali for
3 5 a Period of approximately 1 to 120 minutes.
- 2 -
SUBSTITUTE SHEET (RULE 26)
r . , r ,..... .._.......,.
CA 02290430 1999-11-17
WO 98/52700 PCT/US98/10624
The invention is directed to a ink composition comprising, by weight of the
total
composition:
5-95 % of an acid functional monomer or oligomer,
5-95 %o of a monomer or oligomer that does not contain free acid groups,
5-95 % pigment.
Detailed Description
All percentages mentioned herein are percentages by weight unless otherwise
indicated.
The radiation curable ink compositions used in the method of the invention
must
be operable, when cured, to bond to the vitreous article, which is preferably
glass. In
particular, the ink compositions must be capable of adhering to glass to a
degree
sufficient to permit use as a commercial container used for beverages or other
consumable materials. At the same time, the polymerized ink compositions must
be
capable of being readily stripped or removed from the glass upon exposure of
the
decorated glass to alkali. Glass containers are filled; then they are
decorated with the
2 0 radiation curable ink compositions. After the beverage in the container is
consumed,
the container is returned to the filler. The decorative indicia is stripped
from the glass
upon exposure to alkali. The containers are then cleaned, sterilized, re-
filled, re-
decorated, and shipped again.
Generally, strippable ink compositions are made from radiation curable
monomers and/or oligomers having at least one free acid group. The term "free
acid"
means an acidic group which is capable of reacting with alkali. Examples of
such acidic
groups are carboxylic acid groups, phosphoric acid groups, sulfonic acid
groups and the
like. Preferably, the acid group is a carboxylic acid group. The resulting
polymerized
3 0 coating contains free acidic groups which, upon exposure to alkali, react
with the alkali
to form a salt. As a result, the decorative indicia are much more readily
removable
from the glass. It should be noted that in order for radiation cured glass
coatings to be
considered "high performance", decorative indicia must be capable of
withstanding
3 5 exposure to a concentrated aqueous alkali solution for a period of two to
four hours. In
contrast, the radiation cured ink compositions of the invention must be
completely
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SUBSTITUTE SKEET (RULE 26)
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WO 98/52700 PCT/US98/10624
removed from the glass container upon exposure to aqueous alkali before two
hours has
lapsed; after a period of about ito 120 minutes, preferably about 1 to 60
minutes, more
preferably about 5 to 30 minutes.
THE INK COMPOSITIONS
The Acid-Functional Monomer and/or Olig_,omer
The ink compositions used in the method of the invention, contain about 5-95%,
preferably about 10-85 % , more preferably about 15-75 % of a monomer,
oligomer, or
low molecular weight homo- or copolymer having at least one free acid group. A
variety of such materials are suitable, provided they have at least one free
acid group,
such as a carboxylic acid, sulfonic acid, or phosphoric acid group. The phrase
"having
at least one free acid group" means that the monomer unit has at least one
free acid
group, or the oligomer contains at least one monomer unit containing a free
acid group,
or if a homo- or copolymer, at least one monomer unit thereof contains at
least one free
acid group. Preferably the ink composition contains a monomer or oligomer, in
particular an ethylenically unsaturated monomer or oligomer having at least
one free
2 0 acid group. Examples of preferred monomers or oligomers include those
having
carboxylic acid functional groups such as:
I.
R~
COOH
wherein R, is H, a C,_3~ straight or branched chain, substituted or
unsubstituted,
3 0 saturated or unsaturated alkyl, aryl, aralkyl, a pyrrolidone, or a
substituted or
unsubstituted aromatic, alicyclic, or bicyclic ring where the substituents are
C,_3o straight
or branched chain alkyl, or halogen.
- 4 -
SUBSTITUTE SHEET (RULE 26)
a r
i
1
CA 02290430 2002-04-29
II.
CHz=C
cook
wherein R, is as defined above, and R, is X-COOH wherein X is a C,.3o straight
or
branched chain alkyl, aryl, arylalkyl, or -f-CH:CH;-O-3-"~'-COOH or -f-
CH,CH,CH,-
O~~OOH wherein Y is a C,.,o straight or branched chain alkyl and n is 1-
10,000.
Preferably the monomer or oligomer is of Formula II wherein R, is H or CH3,
and R, is X-COOH wherein X is a C,.,o straight or branched chain alkyl, rr3ore
preferably ethyl. More preferably R= is beta-carboxyethyl, e.g. as in beta-
carboxyethyl
acrylate, which is sold under the tradename B-CEA by UCB Radcure, Inc. B-CEA
is a
reactive monomer which contains both acrylate and carboxylic acid
functionality,
predominantly as the acrylic acid dimer, and, in particular, is a mixture of
about 40 %
by weight B-carboxyethylacrylate, about 40% by weight higher homologs of
acrylic
acid, and about 20% by weight of acrylic acid. The B-carboxyethylacrylate
component
of this mixture has the following formula:
O
H02C-CHz-C1~-O-C-CH=Ct~
In addition, carboxylic acid functional oligomers, such as aromatic acid
methacrylate half esters and aromatic acid acrylate half esters, are also
suitable acid
functional oligomers for use in the method of the invention. Examples of such
oligomers are partial esters of anhydride-containing copolymers such as those
disclosed
in U.S. patent no. 4,7622,947. These copolymers correspond to the following
formula:
- 5 -
SUBSTITUTE SHEET (RULE 26)
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WO 98/52700 PCTIUS98/10624
R~ ~ ~ R3 Ra ~ ~ Ra ~a ~ ~ Ra Ra
I
I I I I ( I
R2 C=0 C=O C=O C=O
x ~ ~ y I I Z I I P
OH ORS OH OB
wherein R, and R~ are each independently hydrogen, C,.Z~ alkyl, aryl, alkaryl,
cycloalkyl, or halogen; R3, R,~, and RS (see below) are each independently
hydrogen, C,
,~, alkyl, or aryl; and R~, is the same or different and is alkyl, aralkyl, or
an alkyl
substituted aralkyl radical containing about 1 to 20 carbon atoms as well as
oxyalkylated
derivatives thereof; and the subscripts x, y, z, and p are each whole numbers
such that
the sum of x, y, z, and p may range from about 3 to 20; and x, p, and y are
each equal
to or greater than I , and z may be 0; and B is BAOCOCRSCH, wherein A is a
linear or
branched divalent alkylene of from about 1 to 20 carbon atoms, or an
oxyalkylated
derivative thereof as described for R6.
2 0 Particularly preferred aromatic partial esters of anhydride containing
copolymers
are those sold by Sartomer, Inc. under the Sarbox tradename, such as SB-400,
SB-500,
and SB-600. Particularly preferred is aromatic acid methacrylate half ester in
ethoxylated trimethylolpropane triacrylate, which is sold by Sartomer, Inc.
under the
2 5 tradename Sarbox SBSOOE50.
Other suitable carboxylic acid functional monomers include acrylic acid,
bisacrylaniidoacetic acid, 4,4-bis(4-hydroxphenyl)pentanoic acid, 3-butene-
1,2,3-
tricarboxylic acid, 2-carboxyethyl acrylate, itaconic acid, methacrylic acid,
4-
Examples of monomers containing sulfonic acid groups include 2-acrylamido-2-
methyl- 1-propanesulfonic acid; 2-methyl-2-propene-1-sulfonic acid. 2-propene-
I-sulfonic
acid. 4- styrenesulfonic acid, 2-sulfoethyl methacrylate, 3-
sulfopropyldimethyl-3-
methacrylamidopropyl ammonium inner salt, 3-sulfopropyl methacryiate,
vinysulfonic
vinylbenzoic acid, and mixtures of these materials.
3 5 acid, and so on.
- 6 -
SUBSTITUTE SHEET (RULE 26)
~ . T
~i
CA 02290430 2002-04-29
~1~U y~/Sl~/UU a a.. a ~ amvn a vv..~
Examples of monomers containing phosphoric acid functional groups include
bis(2- methacryIoxyethyl)phosphate, monoacryloxyethyl phosphate, and so on.
Additional Polvmerizable Reactants
In addition, the ink compositions may contain about 5-95%, preferably about 10-
85 % , more preferably about 15-75 % of other polymerizable reactants such as
radiation
.' curable monomers, oIigomers, or low molecular weight homo- or copolymers,
teipoIymers, or graft or block copolymers which do not contain free acid
groups.
Examples of suitable monomers include epoxides, cycloaliphatic epoxides, vinyl
chloride, styrene, ethyl acrylate, vinyl acetate, difunctional acrylic
monomers such as
hydroxy alkyl acrylates, or hydroxy alkyl methacrylates, vinyl butyrate, vinyl
methyl
ether, methyl methacrylate, isobornyl acrylate, acrylonitrile, or mixtures
thereof.
Suitable polymers include oIigomers, homo- or copolymers, terpolymers, graft
copolymers of the above monomers provided they have a molecular weight of less
than
about 50,000, otherwise it is too difficult to effect polymerization, i.e.
curing.
Preferred are acrylate homopolymers or acrylate or methacrylate copolymers,
preferably
aerylate or methacrylate copolymers. Examples of such acrylate or methacrylate
2o copolymers include epoxy acrylates, copolymers of propylene glycol and a
dicarboxylic
acid, urethane acrylates, and the Like. Preferably, the compositions contain
one or more
polymerizable reactants selected from the group consisting of urethane
acrylate
copolymers, tripropylene glycol acrylate, epoxy acrylate, and mixtures
thereof.
Preferably, the radiation curable compositions of the invention contain about
5-
g5% by weight of acrylate or methacrylate monomers, or homo- or copolymers
which
do not contain acid functional groups.
Pi ment
3 o The compositions used in the invention preferably contain 5-95 %,
preferably 5-
50 % , more preferably 8-35 % by weight of the total composition of pigment. A
wide
variety of pigments are suitable including organic and inorganic pigments.
Examples of
such pigments are set forth in U.S. patent no. 5,178,952. Inorganic pigments
include
3 5 extender pigments such are baryites, barium sulfate, calcium carbonate,
talc, clay,
alumina, titanium dioxide, white carbon, Chinese
SUBSTITUTE SHEET {RULE 26)
CA 02290430 2002-04-29
white, zinc sulfide, lithopone, ultramarine, Prussian blue, cobalt, chrome
oxide, viridian
chrome green yellows, oranges, and reds, cadmium, chromium, iron oxides,
carbon
black, metallic pigments, aluminum powder, bronze powder, zinc chromate,
strontium
chromate, zinc dust, copper, and so on. Examples of suitable organic pigments
include
azo pigments, indolinones, isoindolinones, vat pigments, the Lakes,
pthalocyanine
pigments and so on. The preferred pigment to impart white color to the ink
composition is titanium dioxide. Preferred red and yellow pigments are
isoindolinones
and pyrrolopyrrols as disclosed in U.S. patent nos. 4,415,685; 4,579,949;
4,791,204;
4,666,455; 5,074,918; 4,783,540; 4,914,211; 4,585,878; as well as U.S. patent
no. No.
5,571,359 of Kamen, et al. These pyrrolopyrrols are generally of the formula:
R~ X
1_._R3
X R=
wherein R, and R= are each independently alkyl, arylalkyl, aryl, substituted
or
unsubstituted isocyclic or heterocyclic aromatic radicals; R3 and R4 are each
independently H, substituted or unsubstituted alkyl, alkoxycarbonyl, aroyl
(e.g.
benzoyl), arylalkyl (e.g. benzyl), aryl (e.g. phenyl), alkanoyl, CS_6
cycloalkyl, alkenyl,
alkynyl, carbamoyl, alkylcarbamoyl, arylcarbamoyl, or alkoxycarbonyl; and X is
O or
S. Preferred is a compound wherein R, and R, are each independently phenyl or
3 0 naphthyl, R3 and R4 are hydrogen, and X is O. Particularly preferred as a
red pigment
is pyrroio 3,4-C pyrrol-1,4-dione, 2,5-dihydro-3,6-di-4-chlorophenyl which has
a CAS
number 84632-65-5 and is known by the common name C.I. pigment red 254. This _
pigment is commercially available from Ciba-Geigy Pigments Division, Newport,
DE,
3 5 under the tradename Irgazin DPP Red 80. Other Ciba-Geigy red pigments sold
under
the tradename Irgazin are also suitable.
_ g _
SUBSTITUTE SHEET (RULE 26)
CA 02290430 2002-04-29
Suitable isoindolinones are as set forth in U.S. patent nos. 3,884,955,
3,867,404,
4,978,768, 4,400,507, 3,897,439 and 4,262,120 and 5,194,088. Preferred
isoindolinones
are tetrachlorocyanobenzoic acid alkyl esters, particularly benzoic acid,
2,3,4,5-
tetrachloro-6-cyano-methyl ester which is reacted with 2-methyl-1,3-
benzenediamine and
sodium methoxide. This pigment composition has the common name C.I. Pigment
Yellow 109 and is available commercially from Ciba-Geigy Pigments Division,
Newport
DE under the tradename Irgazin yellow 2GLTE. Other pigments in the Irgazin
Yellow
series as manufactured by Ciba-Geigy are also suitable.
Particularly suitable are blue pigments marketed by Ciba-Geigy under the
tradename Irgazin Blue X-3367, or by Whittaker, Clark, & Daniels under the
tradename
Ultramarine Blue 5009.
Defoaming Agent
The ink compositions used in the invention also preferably contain about 0.01-
10% of a defoaming agent, preferably a polyether-containing defoaming agent,
which
will cause the ink to apply smoothly on the glass substrate without bubbles or
uneveness.
A wide variety of defoamers are suitable, but preferred are defoamers sold by
BYK
Chemie under the BYK tradename. Examples of such defoaming agents are
alkylvinyl
ether polymers set forth in U.S. Patent No. 5,187,201. Examples of other
defoamers
include polyethers such as BYK-052, BYK-053, and BYK-033. BYK-052 and -053 are
polyethers such as polyethylene or polypropylene glycol ethers, and in
particular,
polyvinyl ethers. Also suitable is BYK-354 which is a polyacrylate solution,
and BYK-
022 which is a mixture of hydrophobic solids and foam destroying polysiloxanes
in
polyglycol. Preferably the polyether defoaming agent is an alkoxylated alkyl
phenol,
more particularly a mixtures of petroleum distillates and an ethoxylated alkyl
phenol,
such as that sold by BYK-Chemie under the tradename BYK-033.
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CA 02290430 2002-04!29
Adhesion Promoter
The ink compositions used in the invention also preferably contain about 0.0 1-
25 % , preferably about 0.05-15 %, more preferably about 0.1-5 % of a silane
adhesion
promoter which will enhance adhesion of the cured resin to the glass surface.
Examples
of silanes are silane esters, vinyl silanes, methacryloxy silanes, epoxy
silanes, sulfur
silanes, amino silanes, or isocyanoto silanes. Suitable silanes include
organofunctional
silanes of the formula:
(C~)a
wherein n = 0-3
a = 0-2
Y = NH:, CHI=CH, CH,=C-C00-, CH,-NH-,NH,_-CO-NH-,HS-, Cl-, NH,(CH:),NH-,
CH3
H2C CH p
CH2~- \CH-CHZO-. O=C=N-.
or or
30 X is each independently CHj, C1, OCOCH3, OC,HaOCH3, (OC,H4)ZOCH3. or
OR, where R is a C,.~ straight or branched chain alkyl, preferably methyl or
ethyl.
Silanes having this formula are commercially available under the Dynasylan
trademark from Huls, America, Inc., Piscataway, New Jersey or Osi Specialities
lnc.
Other organofunctional silanes such as those disclosed in U.S. patent no.
5,221,5b0,
are also suitable. Such organosilanes are
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SUBSTITUTE SHEET (RULE 26)
CA 02290430 2002-04-29
~VU I~SI~IIUV t'~.W v~yomvu«
acryloxyfunctional silanes including 3-methacryloxypropyltrimethoxysilane, 3-
acryloxvpropyltrimethoxysilane, 2-methacryloxyethyltrimethyoxysilane, 2-
acryloxyethyltrimethyoxysilane, 3-methacryloxypropyltriethoxysilane, 3-
acryloxypropyltrimethyoxysilane, 3-acryloxypropyitriethoxysilane, 2-
methacryloxyethyltriethoxysilane, 2-methacryloxyethyltriethoxysilane, 2-
acryloxyethyltriethoxysilane, etc. Suitable glycidoxy siIanes include 3 -
glycidoxypropyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-
glycidoxypropyltriethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-
glycidoxypropyltrimethyl silane, and so on. Preferred for use in the
compositions of the
invention are acryloxy- functional silanes, isocyanato silanes, and amino
silanes. The
preferred acryloxy- functional silane is 3- methacryloxypropyl trimethoxy
silane, which
is sold by Huls America, Inc. under the tradename DYNASYLAN MEMO. The
preferred amino silane is sold by Huls America, Inc. under the tradename
DYNAS~'LAN TRIAMO. The preferred isocyanoto silane is sold by Osi Specialities
Inc., under the tradename A-1310. In the preferred ink compositions of the
invention a
mixture of the three silanes is preferred, generally 0.01-2% by weight of
each.
Surfactant
The ink compositions also preferably contain 0.01-20%, preferably 0.5-10%,
more preferably 1-5 % by weight of a fluorinated surfactant. The term
"fluorinated
surfactant" means a fluorine containing compound having at least one
lipophilic group or
portion and at least one hydrophilic group or portion. In particular,
fluorocarbon or
fluorosilicone surfactants are most desirable. Suitable surfactants include
those set forth
in U.S. patent no. 4,961,976. Preferred are fluorocarbon surfactants, such as
those
marketed under the Fluorad trademark by 3M Company. These fluorochemical
3 0 surfactants include fluorinated alkyl esters, fluorinated alkyl
polyoxyethylene
ethanols, and the like. Particularly preferred are nonionic fluorinated alkyl
alkoxylates e.g. those marketed by 3M under the trademark FC-171. Preferred
are fluorinated C,..3o alkyl ethoxylates and propoxylates.
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WO 98/52700 PCT/US98/1Ob24
Photoinitiator
The ink compositions preferably contain a photoinitiator which catalyzes the
polymerization of the monomers upon exposure to the radiation by which the
monomers
are curable. There are generally two types of photoinitiators: free radical
and cationic.
Free radical initiators are more commonly used with ethylenically unsaturated
monomers
and oligomers, while cationic photoinitiators are used with epoxy or vinyl
ether
functional resins. Preferably, the compositions used in the invention contain
free radical
photoinitiators. Suitable tree radical-type photoinitiators include carbonyl
compounds
such as ketones, acetophenones, benzophenones, and derivatives thereof.
Examples of
such materials include, for example, methyl ethyl ketone; benzophenone; benzyl
dimethyl ketal; 1-hydroxycyclohexylphenylketone; diethyoxyacetophenone; 2-
methyl-1-
(methylethiophenyl)-2-(4-morpholinyl)-1-propanone; 2-benzyI-2-N,N-
dimethylamino-
1,4(4-morpholinophenyl)-1-butanone; 2,2-dimethoxy-2-phenyl acetophenone; 2-
methyl-1-
[4-(methylthio)phenyl]-2-morpholino propan-1-one; 2-hydroxy-2-methyl-1-phenyl-
propan-1-one; 4-(2-hydroxyethoxy)phenyl-2(2-hyrroxy-2-methylpropyl)letone; and
a
mixture of bis(2,6-dimethyoxybenzoyl)-2-4-4-trimethylPentyl phosphine oxide
and 2-
hydroxy-2-methyl-1-phenyl-propan-1-one. Preferred is a mixture of 25% bis(2,6-
dimethyoxybenzoyl)-2-4-4-trimethylpentyl phosphine oxide and 75 % 2-hydroxy-2-
methyl-1-phenyl-propan-1-one, which is sold under the tradename Irgacure 1700
by
Ciba-Geigy.
Small amounts of canonically curable monomers or oligomers may be used in the
2 5 compositions of the invention, for example less than about 10 % ,
preferably less than
about 5 % by weight of the ink composition. However, canonically cured
compositions
generally exhibit a high bond strength to glass, such that if they are used in
substantial
amounts in the compositions of the invention, the ink will not be stripped
from the glass
3 o upon exposure to alkali. If cationically curable monomers or oligomers are
used in the
compositions of the invention, it is desirable to use cationic
photoinitiators. The term
"cationic photoinitiator" means a molecule or ingredient which, upon
excitation,
undergoes a photochemical transformation which efficiently generates a species
capable
3 5 of initiating cationic polymerization. If the ink composition of the .
invention is cured by
UV or actinic radiation rather than electron beam it is desirable to add a
cationic
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SUBSTITUTE SHEET (RULE 26)
CA 02290430 2002-04-29
photoinitiator which catalyzes cross-linking of the resin upon exposure to the
radiation to
which the resin is sensitive. On the other hand, if the ink compositions of
the invention
are cured with electron beam it may be possible to dispense with the cationic
photoinitiator. Various types of cationic photoinitiators are suitable. Both
ionic cationic
photoinitiators such as opium salts or organometallic salts are suitable as
well as non-
ionic cationic photoinitiators such as organosilanes, latent sulphonic acids
and the like.
Preferred are photosensitive opium salts, in particular, opium salts such as
those disclosed
in U.S. patent pos. 4,058,401, 4,138,255, 4,161,478, 4,175,972. Triaryl
sulphonium salts
are most preferred, in particular triaryl sulphonium salts such as those sold
by Union
Carbide under the tradename Cyracure UVI 6990 and 6974. Also suitable are
ferrocenium
salts such as those sold under the Irgacure tradename by Ciba-Geigy, in
particular
Irgacure 261. Sulphonyloxy ketones and silyl benzyl ethers are also good
cationic
photoinitiators. A detailed analysis of the mechanism of cationic curing is
disclosed in
"Photosensitized Epoxides as a Basis for Light-Curable Coatings" by William R.
Watt,
American Chemical Society Symposium, Ser. 114, Epoxy Resin Chemistry, Chapter
2,
1979, and in "Chemistry and Technology of UV and EB Formulation for Coatings,
Inks,
and Paints," Volume 3, entitled "Photoinitiators for Free Radical and Cationic
Polymerization," K.K. Dietliker, pages 332-374 ( 1991 ). Photosensitive opium
salts are
used as photoinitiators in cationic curing, in particular, opium salts such as
those
disclosed in U.S. patent pos. 4,058,401, 4,138,255, 4,161,478, 4,175,972.
Triaryl
sulphonium salts are most preferred, in particular triaryl sulphonium salts
such as those
sold by Union Carbide under the tradename Cyracure UVI 6990 and 6974. The
photoinitiator is generally present at about 0.1-15%, preferably about 0.5-
12%, more
preferably about 0.5-10% by weight of the total composition.
The preferred ink compositions used in the invention comprise:
5-95% of an ethylenically unsaturated monomer or oligomer containing at least
one free acid group,
5-95% pigment, and
5-95% of a monomer or oligomer free of acid groups.
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More preferably, the ink composition comprises, in addition, an ingredient
selected from the group consisting of about 0.1-25 % of a silane adhesion
promoter,
about 0.01-10% of a polyether defoaming agent, about 0.01-20% of a fluorinated
surfactant, and about 0.1-1 % of a photoinitiator.
THE DECORATING METHOD
The term "ceramic" or "vitreous article" when used in accordance with the
invention shall mean glass, ceramic, tile, and similar vitreous materials. The
articles
which may be decorated or printed according to the method of the invention may
be in
any shape or form, such as a container, sheet, tile, figurine, or the like. In
the
preferred embodiment of the invention the article is made of glass or ceramic
and is a
container, such as a cosmetic or beverage container.
The ink composition is applied to the article to be decorated in a
predetermined
design using a variety of printing methods including screen printing, offset
printing,
gravure, hand painting and the like. After the ink is applied the substrate or
article is
irradiated with UV or actinic radiation using a conventional UV light source.
The term
2 0 ~~ UV " means ultraviolet light which generally has a wavelength of 4 to
400, preferably
325 to 400 nanometers. The term "actinic" means radiation having a wavelength
of 200
to 600 nanometers. Electron beam may be used instead of a UV light source. If
a UV
conveyer is used, it is set up so that the substrate passes through the beam
of radiation
for an amount of time appropriate to completely cure the ink composition and
cause it to
2 5 adhere to the substrate. If desired, the substrate may he moved through
the conveyer in
one or more passes to achieve the required curing. The appropriate time varies
depending on the ink formula, but generally curing is complete in a period of
time
ranging from fractions of a second to 30 minutes. It is preferred, that by the
time the
3 0 decorated substrate or article is removed from the conveyer, the ink is
completely cured
and fused to the substrate surface. In some cases it may be necessary to
subject the
newly screened glass container to slightly elevated temperature prior to UV
curing the
applied ink on the substrate, or to an additional post-UV cure application of
heat to
3 5 finally polymerize the ink on the substrate. Preferably, the decorated
substrate is
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SUBSTITUTE SHEET (RULE 26)
CA 02290430 2002-04-29
subjected to post-UV cure heating at a temperature of 90 to 2000°C.,
preferably 100-
200°C. for a period of 0.5 to 30 minutes.
The ink compositions are well suited for use in automated systems such as a
multiple color printing apparatus or with the methods disclosed in U.S. patent
no.
5,562,951.
In another embodiment of the invention, it is possible to make the ink
composition of the invention without the pigment and print it on the glass
substrate in
predetermined design according to the methods described above. For example, a
substrate such as a container may be decorated in a pre-determined design by
silk
screening the unpigmented ink composition on the substrate and curing with the
appropriate radiation. A layer of hot stamping foil is then compressed against
the
substrate with a press which is heated to a temperature sufficient to cause
the hot
stamping foil to adhere to the printed ink design but not to the ink-free
areas of the
glass. Hot stamping foil is generally a laminate comprised of a carrier
material (often
polyester or a similar material capable of release), a release film between
the carrier and
a subsequent decorative coat which is usually color or a metallized coat, most
often
aluminum or colored aluminum. The foil may contain other optional layers such
as one
or more protective layers, hot melt adhesive layers, etc. between the
metallized layer or
layers and the carrier material. More specifically, hot stamping foil can be
defined as a
multilayer web comprised of a backing film carrier, a release coating, one or
more
protective top coatings, one or more color coatings, and a hot melt adhesive
in that
order. The hot stamping foil is then compressed against the container with the
hot melt
adhesive layer being compressed against the substrate. The compress, which may
be a
standard hot stamping press or a hand held press, is heated to a temperature
sufficient to
cause the hot melt adhesive layer of the hot stamping foil to adhere to the
ink decorated
portion of the substrate. Generally this temperature ranges from about 250 to
4000°F.
Temperatures higher than this may cause deterioration of the hot stamping
foil. The
application of heat causes the adhesive side of the hot stamping foil to
become
adhesively adhered to the ink design but not to the ink-free areas of the
substrate.
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WO 98/52700 PCT/US98/10624
When the compress is removed, a portion of the foil laminate adheres to the
ink
decoration but not to the ink free areas of the glass. In particular, adhered
to the ink
design on the substrate is the hot melt adhesive layer, the color coatings,
and the
protective top coatings, in that order, of the hot stamping foil. Portions of
the release
coating may or may not be adhered to the protective top coating because the
release
coating is designed to melt upon application of heat and cause the polyester
carrier
backing layer to release from the protective top coat layer and some remnants
may
remain. The resulting hot stamped substrate exhibits a metallic gold, silver,
or colored
appearance depending on the color of the hot stamping foil.
In yet another embodiment of the invention, it is possible to provide a
decorated
substrate which has a two tone effect where atl or a portion of the colored
ink on the
substrate is hot stamped. In this instance a pigmented ink composition is
applied to the
substrate in a predetermined design and cured by exposing it to the radiation
by which it
is curable for a time sufficient to effect complete cure. Hot stamping foil is
applied as
described above to either the entire ink design or to only a part (i.e.
complete or partial
registration}. If the hot stamping foil is applied in partial registration, or
applied to a
2 0 p°rtion of the pigmented ink design, a pleasant two tone effect is
achieved. Many times
it is more economical to print the entire design on the substrate using
colored ink and
then hot stamp over the desired portion of the design, rather than applying
clear ink and
hot stamping, and then printing colored ink in the desired design in a second
application.
The ink compositions of the invention provide sufficient adhesion to glass as
well
as exhibiting sufficient resistance to scuffing and scratching to make the
decorated
articles suitable for use on commercial beverage and cosmetic bottles.
3 0 THE STRIPPING METHOD
The ink compositions of the invention can be removed from glass upon exposure
of the glass to alkali. In particular, the free acid groups found in the
polymerized ink
composition are capable of reacting with the hydroxyl groups of the base to
form a salt
which is easily stripped or removed from the glass.
- 16
SUBSTITUTE SHEET (RULE 26)
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WO 98/52700 PCT/US98/10624
The aqueous alkaline solution comprises about 1-20%, preferably about 2-15%,
more preferably about 2-12% by weight alkali. Suitable alkali materials
include metal
hydroxides (e.g. alkali metal and alkaline earth metal hydroxides) such as
sodium
hydroxide, potassium hydroxide, calcium hydroxide, and the like.
The cured ink compositions should be removed from the glass upon exposure to
the aqueous alkali after a period of about 1 to 120, preferably about 1-60,
more
preferably about 1-30 minutes. The glass substrate is generally immersed in
the
aqueous alkali solution for the appropriate time period, after which the ink
compositions
are removed from the glass surface.
Preferably the glass container is subjected to the aqueous alkaline solution
at a
temperature of 60 to 1000 C., more preferably 70 to 950 C., most preferably 72
to 900
C.
In the most preferred embodiment of the invention the ink composition is
removed from the glass containers after exposure of the glass to a 4 %
(approximately)
aqueous solution of sodium hydroxide at a temperature of 70 to 1000 C, after 1-
15
minutes.
2 0 The decorating method and compositions of the invention are excellent for
use on
glass containers used in the returnable beverage market. The decorative
indicia applied
according to the invention remains on the glass for the useful commercial life
of the
container, yet can be easily removed upon exposure to an aqueous alkali
solution. This
eliminates the need for paper labels and decals, which results in a
significant cost
savings. Also, the indicia are much more aesthetically pleasing, similar to
the aesthetics
achieved with ACL. Thus, beverage and cosmetic manufacturers are able to offer
glass
containers that provide aesthetics similar to ACL, with indicia that can be
easily
removed upon exposure to alkali solutions when the glass container is returned
to the
3 0 filler.
The invention will be further described in connection with the following
examples, which are set forth for the purposes of illustration only.
3 5 EXAMPLE 1
A white ink composition was made as follows:
rams wt
- 17 -
SUBSTITUTE SHEET (RULE 26)
CA 02290430 1999-11-17
WO 98/52700 PCT/US98/10624
Dipentaerythritol pentaacrylate' 25.0 24.8
Epoxy acrylate + tripropylene glycol acrylate327.0 26.8
Aromatic acid methacrylate 1/2 ester
in ethoxylated trimethylolpropane
triacrylate3 5.0 5.0
Beta carboxyethyl acrylatea 10.0 9.9
Aromatic urethane acrylate with
polyacrylated polyol diluent5 10.0 9.9
Titanium dioxide (pigment) 17.0 16.9
l0
Irgacure 17006 3.0 3.0
Gamma-isocyanotopropyltriethoxysilane' 0.5 0.5
3-methacryloxypropyl trimethoxysilane$ 0.5 0.5
Trimethoxysilylpropyldiethylene triamine'' 0.5 0.5
Fluorinated alkyl alkoxylate' 0.5 0.5
BYK-033" 1.0 1.0
Modaflow'Z 0.8 0.8
' SR399, Sartomer Company, Inc. (other polymerizable reactant)
2 CN104, Sartomer Company, Inc. (other polymerizable reactant)
3 SB500 E50, Sartomer Company, Inc. (polymerizable reactant with free acid
group)
4 B-CEA, UCB Radcure Inc. (polymerizable reactant with free acid group)
5 EB-220, UCB Radcure Inc. (other polymerizable reactant)
G Ciba-Geigy Corp. Mixture of 25 % by weight bis(2,6-dimethoxybenzoyl)-2,4-,4
trimethylpentyl phosphine oxide and 75 % by weight 2-hydroxy-2-methyl-1
phenylpropan-1-one. (photoinitiator)
' A-1310, Osi Specialties, Inc. (adhesion promoter)
8 DYNASYLAN MEMO, Huls America Inc. (adhesion promoter)
y DYNASYLAN TRIAMO, Huls America Ine. (adhesion promoter)
'° FC-171, 3M Company (surfactant)
" BYK-033, BYK-Chemie. A mixture of 92% by weight of petroleum distillates and
5% by
weight ethoxyiated alkyl phenol (defoaming agent)
'2 Modaflow, Monsanto, Inc. Ethyl acrylate and 2-ethylhexyl acrylate copolymer
(defoaming
agent)
3 5 EXAMPLE 2
A blue ink composition was made as follows:
r~ ams wt
- 18 -
SUBSTITUTE SHEET (RULE 26)
T
CA 02290430 1999-11-17
WO 98/52700 PCT/US98/10624
Dipentaerythritol pentaacrylate' 25.0 23.9
Epoxy acrylate + tripropylene glycol acrylate3 27.0 25.8
Aromatic acid methacrylate 1/2 ester
in ethoxylated trimethylolpropane
triacrylate3 5.0 4.8
Beta carboxyethyl acrylate 10.0 9.6
Aromatic urethane acrylate with
polyacrylated polyol diluent5 10.0 9.6
10Ultramarine blue 5009'3 20.0 19.1
Irgazin blue X-3367'4 1.0 0.9
Irgacure 17006 3.0 2.9
Gamma-isocyanotopropyltriethoxysilane' 0.5 0.5
3-methacryloxypropyl trimethoxysilane~ 0.5 0.5
Trimethoxysilylpropyldiethylene triamine'' 0.5 0.5
Fluorinated alkyl alkoxylate' 0.5 0.5
BYK-033" 1.0 1.0
Modaflow'2 0.5 0.4
' SR399, Sartomer Company, Inc. (other polymerizable reactant)
2 CN104, Sartomer Company, Inc. (other polymerizabie reactant)
3 SB500 E50, Sartomer Company, Inc. (polymerizable reactant
with free acid group)
~ B-CEA, UCB Radcure Inc. (polymerizable reactant with
free acid group)
5 EB-220, UCB Radcure Inc. (other polymerizable reactant)
'' Ciba-Geigy Corp. Mixture of 25% by weight bis(2,6-dimethoxybenzoyl)-2,4-,4-
25trimethylpentyl phosphine oxide and 75% by weight 2-hydroxy-2-methyl-1-
phenylpropan-1-one. (photoinitiator)
' A-1310, Osi Specialties, Inc. (adhesion promoter)
8 DYNASYLAN MEMO, Huls America Ine. (adhesion promoter)
9 DYNASYLAN TRIAMO, Huls America Inc. (adhesion promoter)
' FC-171, 3M Company (surfactant)
3 " BYK-033, BYK-Chemie. A mixture of 92 % by weight of petroleum
0 distillates and
5 %a by
weight ethoxylated alkyl phenol (defoaming agent)
'Z Modaflow, Monsanto, Inc. Ethyl acrylate and 2-ethylhexyl
acrylate copolymer
(defoaming
agent)
'3 Wittaker, Clark, & Daniels (pigment)
3 ~a Ciba Pigment Division
5
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SUBSTITUTE SHEET (RULE 26)
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WO 98/52700 PCT/US98/10624
EXAMPLE 3
A white ink composition was made as follows:
rg ams wt %
Aromatic acid methacrylate 1/2 ester in ethoxylated 25.0 24.5
trimethylolpropane triacrylate'
Beta carboxyethyl acrylate2 35.0 34.2
Monofunctional acrylate resin' 15.0 14.7
Epoxy acrylate + tripropylene glycol acrylate~ 5.0 4.9
Titanium dioxide 15.0 14.7
Irgacure 17005 3.0 2.9
BYK-033'' 1.0 1.0
3-methacryloxypropyl trimethoxysilane' 0.6 0.6
Gamma-isocyanotopropyltriethoxysilane~ 0.6 0.6
Methyl diethanolamine 2.0 1.9
' SB500, Sartomer Company, Inc. (polymerizable reactant with free acid group)
'- B-CEA, UCB Radcure Inc. (polymerizable reactant with free acid group)
3 Aromatic oligomer containing pendant carboxy functional groups, Henkel
Corporation
(polymerizable reactant with free acid group)
~ CN 104, Sartomer Company, Inc. (other polymerizable reactant)
5 Ciba-Geigy Corp. Mixture of 25 % by weight bis(2,6-dimethoxybenzoyl)-2,4,4-
trimethylpentyl phosphine oxide and 75 % by weight 2-hydroxy-2-methyl-1-
phenylpropan-1-one. (photoinitiator)
2 5 '' BYK-Chemie, A mixture of 92 % by weight petroleum distillates and 5 %
by weight
ethoxylated
alkyl phenol (defoaming agent)
' DYNASYLAN MEMO, Huls America Inc. (adhesion promoter)
g A-1310, Osi Specialties, Inc. (adhesion promoter)
3 0 The ingredients were combined and mixed well.
EXAMPLE 4
An ultramarine blue composition was made as follows:
rg ams wt %
- 20 -
SUBSTITUTE SHEET (RULE 26)
CA 02290430 1999-11-17
WO 98/52700 PCT/US98/10624
Aromatic acid methacrylate 1/2 ester in ethoxylated 25.0 24.2
trimethylolpropane triacrylate'
Beta carboxyethyi acrylate2 30.0 29.1
Monofunctional acrylate resin3 15.0 14.5
Epoxy acrylate + tripropylene glycol acrylate4 5.0 4.8
Irgazin blue X-33675 1.0 1.0
Ultramarine blue 50096 20.0 19.4
Irgacure 1700' 3.0 2.9
BYK-0338 1.0 1.0
3-methacryloxypropyl trimethoxysilane~ 0.6 0.6
Gamma-isocyanotopropyltriethoxysilane' 0.6 0.6
Methyl diethanolamine 2.0 1.9
' SB500 E50, Sartomer Company, Inc. (polymerizable reactant up)
with free acid gro
2 B-CEA, UCB Radcure Inc. (polymerizable reactant with free
acid group)
3 Aromatic oligomer containing pendant carboxy functional
groups, Henkel Corporation
(polymerizable reactant with free acid group)
4 CN 104, Sartomer Company, Inc. (other polymerizable reactant)
5 Ciba Pigment Division (pigment)
2 0 ~~ whittaker, Clark, & Daniels (pigment)
' Ciba-Geigy Corp. Mixture of 25 % by weight bis(2,6-dimethoxybenzoyl)-2,4,4-
trimethylpentyl phosphine oxide and 75 % by weight 2-hydroxy-2-methyl-1-
phenyl-propan-1-one. (photoinitiator)
'' BYK-Chemie, A mixture of 92 % by weight petroleum distillates
and 5 % by weight
ethoxylated
2 5 alkyl phenol (defoaming agent)
' DYNASYLAN MEMO, Huls America Inc. (adhesion promoter)
$ A-1310, Osi Specialties, Inc. (adhesion promoter)
The ingredients were combined and mixed well.
EXAMPLE 5
A white ink composition was made as follows:
- 21 -
rams wt
SUBSTITUTE SHEET (RULE 26)
CA 02290430 1999-11-17
WO 98/527n0 PCT/US98/10624
Aromatic acid methacrylate 1/2 ester in ethoxylated25.0 22.8
trimethylolpropane triacrylate'
Epoxy acrylate + tripropylene glycol acrylatez10.0 9.1
Beta-carboxyethyl acrylate3 30.0 27.3
Monofunctional acrylate resin4 15.0 13.7
Polytetrafluoroethylene5 1.0 0.9
Titanium dioxide 17.0 15.5
Iragacure 17006 3.0 2.7
BYK-033' 1.5 1.4
3-methacryloxypropyl trimethoxysilane8 0.6 0.5
Gamma-isocyanotopropyldiethylene triamine' 0.6 0.5
Monodiethanolamine 3.0 2.8
Be~ophenone 3.0 2.8
SB500, Sartomer Company, Inc. (polymerizable reactant with free acid group)
2 CN 104, Sartomer Company, Inc. (other polymerizable reactant)
3 B-CEA, UCB Radcure Inc. (polymerizable reactant with free acid group)
4 Aromatic oligomer containing pendant carboxy functional groups, Henkel
Corporation
2 0 (poiymerizable reactant with free acid group)
5 SST-4, Shamrock Technologies, Inc. (thickening agent)
6 Ciba-Geigy Corp. Mixture of 25 % by weight bis(2,6-dimethoxybenzoyl)-2,4,4-
trimethylpentyl phosphine oxide and 75% by weight 2-hydroxy-2-methyl-1-
phenyl-propan-1-one. (photoinitiating agent)
' BYK-Chemie. A mixture of 92 % by weight petroleum distillates and 5 % by
weight
alkyl phenol (defoaming agent)
2 5 ~ DyNASYLAN MEMO, Huls America Inc. (adhesion promoter)
g A-1310, Osi Specialties, Inc. (adhesion promoter)
The composition was made by combining the ingredients and mixing the
ingredients well.
EXAMPLE 6
A blue ink composition was made according to the following formula:
rams wt %
3 5 Aromatic acid methacrylate 1 /2 ester in ethoxylated 25.0 24.7
trimethyiolpropane triacrylate'
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SUBSTITUTE SHEET (RULE 26)
r , 1
CA 02290430 1999-11-17
WO 98/52700 PCT/US98/10624
rams wt
Epoxy acrylate + tripropylene glycol acrylate210.0 9.9
Beta-carboxyethyl acryate3 25.0 24.7
Monofunctional acrylate resins 15.0 14.8
Ultramarine blue 50095 15.0 14.8
Irgazin blue X-33676 1.5 1.5
Polytetrafluoroethylene' 1.0 1.0
Iragacure 17008 3.0 3.0
Benzophenone 3.0 3.0
BYK-033'' 1.5 1.4
3-methacryloxypropyl trimethoxysilane' 0.6 0.5
Gamma-isocyanotopropyltriethoxysilane" 0.6 0
5
.
' SB500 E50, Sartomer Company, Inc. (polymerizable
reactant with free acid group)
2 CN 104, Sartomer Company, Inc. (other polymerizable reactant)
3 B-CEA, UCB Radcure Inc. (polymerizable reactant with free acid group)
4 Aromatic oligomer containing pendant carboxy functional groups, Henkel
Corporation
2 0 (polymerizable reactant with free acid group)
5 Whittaker, Clark & Daniels (pigment)
6 Ciba Pigment Division (pigment)
' SST-4, Shamrock Technologies, Inc. (thickening agent)
$ Ciba-Geigy Corp. Mixture of 25 % by weight bis(2,6-dimethoxybenzoyl)-2,4,4-
trimethylpentyl phosphine oxide and 75% by weight 2-hydroxy-2-methyl-1-
phenyl-propan-1-one. (photoinitiating agent)
2 5 ~ ByK-Chemie, A mixture of 92 % by weight petroleum distillates and 5 % by
weight
ethoxylated
alkyl phenol (defoaming agent)
'° DYNASYLAN MEMO, Huls America Inc. (adhesion promoter)
" A-1310, Osi Specialties, Inc. (adhesion promoter)
3 0 The ingredients were combined and mixed well.
EXAMPLE 7
The white ink composition of Example 2 was applied to alcoholic beverage
3 5 bottles by screen printing with a 230 mesh screen using an Autoroll M-25
semi-
automatic screen printing machine. The ink on the bottle was screened by
exposure to
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SUBSTITUTE SHEET (RULE 26)
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WO 98/52700 PCT/US98/10624
UV light from a P600 power supply having a 9mm. D bulb. The curing speed was
less
than one second per bottle. Then, the blue ink of Example 2 was screened onto
the
bottle in partial registration with the cured white ink. The ink was cured
upon exposure
to the UV light source. The bottle was then subjected to post heat curing at a
temperature of 100° C. for 30 minutes. The indicia adhered well to the
bottle and
exhibited bright, true coloration.
EXAMPLE 8
The finished bottles decorated in accordance with Example 7 were immersed in a
water bath containing 4% sodium hydroxide at a temperature of 72° C.
The cured inks
were completely removed from the bottles after 4 minutes.
While the invention has been described in connection with the preferred
embodiment, it is not intended to limit the scope of the invention to the
particular form
set forth but, on the contrary, it is intended to cover such alternatives,
modifications,
and equivalents as may be included within the spirit and scope of the
invention as
defined by the appended claims.
25
35
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SUBSTITUTE SHEET (RULE 26)
