Note: Descriptions are shown in the official language in which they were submitted.
~22~6~
HEAT TRANSFER PAD DECORATION ANn SU13STRAT~S T~IEREFOR
BACK(~ROUNr~ OF TIIE~ IMVE:NTION
~_ _ __ _
1. Field of the Invention
__
The present invention relates to heat transfer
decoration, as well as to the decoration of objects using
a deformable pad. The invention further relates to the
design of labels transferrable by these methods.
2. ~escription of the Prior Art
A widely employed prio,r art method for imprinting
designs onto articles using a heat transfer labelling
process employs a paper base sheet or web coated with a
label consisting of a release layer over which a design is
imprinted in ink. In one successful technique of heat
transfer decoration, labels of the above description are
transferred to bottles or other articles using heat and
pressure by feeding the article to a transfer site, where
the preheated label-bearing web is impressed against the
bottle to transfer the label. Patents illustrative of the
above method and apparatus, commonly assigned with the
present application, include U.S. Patent Nos. 2,981,432;
3,064,714; 3,079,97~; 3,20~,897; 3,231,448; 3,261,734; and
4,214,937. This decorating technique, w~ile highly
successful in achieving high quality label transfer to
bottles and similar articles, suffers certain limitations
2~ in the decoration of articles of unusual shape. Since the
laminate is transferred directly to the article from a
broad continuous web, the laminate lacks sufficient
flexibility to conform to surfaces having compound or
sharp curvature. The method is therefore not easily
adaptable to imprinting objects having surfaces of
compoun~ or irregular curvature or recessed panels.
.
~ 2 ~
Another type of apparatus which possesses special
advantages in the decoration of objects of unusual
conformation is the so-called pad-transfer decorator.
This apparatus utilizes a deformable pad, typically
comprised of a silicone elastomer. The pad receives an
ink impression to be transferred to an article by pressing
against an intaglio plate which had been previously coated
with ink with any e~cess ink removed. The împression-
bearing pad is then presse'd against the article to be
labelled, to which it imparts the ink impression. The
deformable pad is adaptable to a wide varie~y of article
conformations. This decorative method and apparatus
involves assembly-line equipment of a simpler design than
the above-discussed heat-transfer decorators, and
therefore re~uires fewer adjus.ments in retooling to
articles of a va.iety of sizes and shapes. ~owever, this
process only transfers one color of ink at a time, and is
thus slow and cu~bersome if multicolored designs are
required. Also, since there is no protective coating
covering the ink design, it is left exposed directly to
the environment upon transfer to the article.
U.S~ Patent ~o. 3,887,420 discloses the use of a
silicone rubber p~d to transfer designs from a decorative
Iaminate to ceramic articles. The laminate includes a
base layer such as a paper sheet overlayed with a coating
of wax. The wax coating is ~oated with a film layer (Fi-lm
B), which in turn is overcoated with an ink design layer
and a second film (Film A). As the laminate is heated to
within a narrow ten degree temperature range, Film A is
alleged to become adhesive while the wax coating and Film
B become molten and nonadhesive. The transfer pad
purportedly sticks to Film A when it is pressed against
the laminate so that as the transfer pad is withdrawn, the
~2~ 68~
substrate composed of the paper sheet and wax coating separates
from the remainder of the laminate. The laminate adhering to the
transEer pad is pressed onto a ceramic article, and the
temperature of the laminate is dropped to within a narrow ten
degree temperature range. At this temperature, Film B becomes
adhesive and Film A is alleged to exhibit diminished adhesion.
Thus, as the laminate is pressed onto the article with Film B
contacting the article, the laminate is alleged to adhere to the
article and released from the transfer pad as the pad is
withdrawn.
The film layers A and B are each adhesive over only a
very narrow ten degree temperature range, making it imprac-ticable
to control the described process within the context of an
automated process, since each Eilm layer must in turn be heated
or cooled to within the required ten degree temperature range to
make the process workable. Precise heating or cooling of Film A
and Film B to within such narrow temperature ranges is impossible
to achieve or control within the split second time intervals
required by an automated assembly process. This reference does
not disclose the use of an independent pad heater, nor details of
pad composition, surface texture, or other parameters important
to its implementation. Furthermore, the inclusion of a wax layer
to form part of the decorative substrate has the disadvantage
that as the substrate is released from Film B there will be a
strong tendency for a portion of the wax to remain attached to
Film B. This will interfere with the adhesive characteristics of
Film B as the laminate is transferred from the transfer pad to an
object.
122268~
U.S. Patent No. 3,616,176 discloses a heat transEer
laminate of a type related to that disclosed in U.S. Patent
3,616,015. In U.S. Patent 3,616,176 the laminate is composed of
a base sheet, with a polyamide layer covering the base sheet and
a decorative ink layer covering the polyamide layer. Sufficient
heat is applied to the laminate to heat the polyamide layer at or
above its softening point, and the laminate is then pressed onto
the surface of an article with the decorative ink layer coming
into direct contact. Upon withdrawal of the heat source, the
polyamide layer cools LO a temperature below its softening point
and the base sheet is removed. The decorative layer becomes
fused or heat sealed to the article. Since the polyamide layer
lies over the decorative layer, it does not contact the article
direc-tly and therefore does not function as a contact adhesive.
The decorative laminate disclosed in U.S. Patent 3,616,176 has a
significant disadvantage that since the base sheet is in contact
with the laminate as it is imprinted onto the article, the
laminate lacks sufficient flexibility to satisfactorily imprint
surfaces having compound or sharp curvature.
A further heat transfer label of the type shown in U.S.
Patent No. 3,616,015 known to the Applicant is composed of a
carrier member (base sheet) overcoated in designated regions with
a release layer and an ink design layer. Optionally, a barrier
layer is included between -the release layer and the ink layer.
The release layer is typically composed of a polymerization
product of a diamine with the dimer of a fatty acid and is
contoured to reduce the halo effect of the label as it is
-transEerred onto an article. The optional barrier layer may be
~2~6~
formed of an aroma-tic acid-based polyes-ter covering and
overlapping -the release layer by a margin. This form oE label
does not suggest a solution to the above-men-tioned limitations of
the heat transfer labelling process.
Yet another heat transfer label of the type shown in
U.S. Patent No. 3,616,015 known to the Applicant is composed of a
carrier member (base sheet) overcoated in designated regions with
a release wax layer, a protective layer, an ink design layer, and
an adhesive layer. The protective layer provides enhanced
chemical resistance for the heat transfer label and permits the
heat transfer label to resist distortion during the heat transfer
process. The protective layer is typically composed of an
aromatic acid-based polyester and a rosin ester. This form of
label does not suggest a solution to the above-mentioned
limitations of the heat transfer labelling process.
Accordingly, it is an object of the present invention
to provide decorative methods suitable for automated transfer of
labels to articles, and substrates to be transferred by this
method. It is a particular object of such method and apparatus
that it combine the advantages of adaptability to a variety of
article sizes and shapes and multicolored label capabilities.
Another object of the invention is that the technique
be readily adapted to rapid and efficient operation. A related
object is a multicolored decoration capability without the need
for successive decorative stages.
~ et another object of the invention is the provision of
a decorative process which is adaptable to a variety of
artlcles. Such technique, for example, should be suited to the
_ 5
1~2~
decoration oE plastic, glass, and ceramic articles.
Still another object oE the invention is the
achievement of high quality decora-tion of articles. The
apparatus of the invention should impart a desired image
completely and without significant distortion. A particular
object in -this regard is the provision of high gloss images. A
further object of the invention is the provision of durable,
reasonably inexpensive decoration.
Another object of the invention is to provide a
decorative laminate which achieves multicolor pad -transfer
decoration ln a single transfer operation.
Another object of the invention is to provide a
decorative laminate which permanently adheres to any article
! without subsequent firing of the laminate.
A further object of the invention is to achieve a pad
transfer method which satisfies the above criteria while being
compatible with automated operation.
6~3~
S~ ~ARY ~F T~F, INVFNTInN
In accomplishing the foregoing and related objects,
the invention provides 8 transfer process employing a
decorative laminate including a ~esign and transfer
substrate which are transferred from a support member to a
transfer pad and thence to an article. The support member
is heated to a first temperature, permitting separation of
the transfer substrate which adheres to the pad. The
surface of the pad is advan~ageously at a second, somewhat
lower temperature. The transfer substrate is pressed
against the article forming an adhesive bond thereto, and
is released by the pad.
In the preferred embodiment, the transfer substrate
includes an adhesive/release layer which is softened by
the heating of the support member and separated therefrom
during the first transfer. This layer also functions as
an adhesive, forming a permanent bond to the article
during the second transfer. ~he transfer substrate
further includes an ink design layer over the adhesive
layer. Optionally, the substrate includes a protective
coating layer over the ink layer; this layer may be
omitted in many applications.
nptionally, the transfer substrate further includes a
barrier ~ayer intermediate the adhesive/release layer and
the ink layer. The barrier layer, where included,
functions to prevent absorption of ink into the resin~us
coating.
The invention has the advantage that the transfer
substrate may be composed vf either a single colored
decorative design or a multicolored decorative design
including halftone colors. Another advantage of the
invention is that the transfer substrate may be
transferred to virtually any type of article irrespective
,
,. '' 11 ~
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of its sh~pe or degree of surface curvature without
causing distortion to the desi~n imprint. Thus, the
article may, for example, be composed of ceramic, glass,
plastic, paper foil, and a variety of polymeric materials,
and the surface to which the transfer substrate is
transposed may be flat or include compound curves,
irregular surfaces, or recessed panels.
The decorative lamina,te of the preferred embodiment
includes a paper shee~ or web, which is coated on one side
~- 10 with the various layers constituting the transfer
substrate. m e transfer substrate includes a resinous
coating layer in contact with the support (i.e., the
adhesive/release layer), an ink layer covering the
resinous coating layer and a protective coating layer over
the ink layer. The use of a resinous adhesivelrelease
layer distinguishes the transfer substrate of the
invention from those of the prior art incorporating a wax
release l~yer or the like, which cannot also successfully
function as an adhesive layer.
2n In the preferred embodiment, the barrier layer where
include~ is of the same composition as the protective
coating.
A preferred for~ulation for the adhesive/release
layer is a polyamide resin made from the polymerization of `~
~ diamine with a dimer of a fatty acid~ Preferably, this
layer includes a plasticizer such as castor oil, w~ich may
be modified by the addition of erucamide (a fatty amide of
cis-13-decosenoic acid). Partic~larly favorable
, properties are achieved in this layer when it co~prises at
least 80 percen~ by weight polyamide resin, the balance
being a plasticizer.
Additional plasticizer may be included in the
formulation of the adhesive/release layer to increase its
~Z~26~3~
fluidity. Where erucamide is included in the
adhesive/release layer the above-mentioned proportions are
suitably adjusted so that the polyamide resin comprises
at least 7~ percent of the formulation, more preferably
between 70 and 90 percent. Advantageously, in the
adhesive/release layer as so modified the ratio o
plasticizer to erucamide is in the range 5/1 to 15/1.
The preferred polyamide resin is composed of the
polymerization product of a linear methylene dlamine and
dimerized fatty acid. Specific polyamide resins which
have been found to be particularly suitable are the
polymerization products of hexamethylene diamine and
dimerized linoleic acid, and tetramethylene diamine and
dimerized oleic acid.
Alternative constituents for the resinous coating may
include polyterpenes, vinyl ~oluene/alpha methyl styrene
copo~ymers and ethylene/vinyl acetate copolymers. These
constituents may be used without additional additives, or
plasticizers such as castor oil may be added with or
without erucamide.
A preferred plasticizer is castor oil. Alternative
plasticizers may include rosin esters, chlorinated
paraffins, aliphatic esters, epoY~y esters, alkyl aromatic
phthalates, glycol esters, and alkyl aromatic phosphates.
Applicants have found that a preferred composition
for the dried protective coating and optional barrier
layer consists of the combination of a polymer (i) which
is a film forming, multiaromatic, acid-based polyester,
preferably linear which is reinforced by a second polymer
(ii) containing bulky ring structures such as polymerized
rosin esters. The multiaromatic acid-based polyester
(Polymer (i)) should comprise between about 50 to 80
percent by weight of the dried protective coating layer or
6~34
the optional barrier layer with the polymerized rosin
ester (Polymer (ii)) comprising the balance of the mixture,
i.e. between about 20 to 50 percent by weight.
The multiaromatic ~cid-based polyester (Polymer (i))
is preferably composed of the polymer condensation
products of polyester formin~ reactants of one or more
glycol6 reacted with napthalic pr phthalic acidsO
A preferred rosin est~r (Polymer ~ ) is forme~
typically of the reaction product of a polyhydric alcohol,
maleic anhydride or phenol aldehyde reacted with rosin
acids such as abietic and pimaric acids. ~he rosin ester
(Polymer (ii)) is preferably composed of methyl abietate,
methyl hydroabietate, glyceryl hydroabietate or ester
gum,
The ink layer may be composed of a single colored ink
or may include a multiplicity of differently colored inks.
The ink may be composed of any conventional nitrocellulose
ink, preferably a polyamide-nitrocellulose ink.
Alternatively, inks having an acrylic polyester, or vinyl
base are al60 particularly suitable.
If the transfer su~strate does not include a
protective layer, the ink layer is preferably composed of
an isobutyl methacrylate ink modified with maleic rosin
and p~lyisoprene. Alternatively, inks having a polyamide-
nitrocellulose or vinyl base may be-adopted if the
substrate does include a pr~ective layer,
i The basis wei~ht of the dried resinous coating layer
may advantageously fall in ~he range 1.5 to 15 lbs./ream,
and the dried protective coating layer or barrier layer
from about 0.5 to 3 lbs./ream (3000 6q. ft. per ream).
In a preferred implementation of the transfer
process, heat is conducted through an exposed undersurface
of a support web, supplied ~rom a heated platen or the
:
., .
7~
~ Z ~2 6~ ~
like. Sufficient heat is supplied to tackify the
protective coatin~ layer (or ink layer, where the
protective coatin~ is omitted) and to æoften and begin to
melt the adhesive/release layer. As a result, the
protective coating adheres to the surface of the transfer
pad, and the softened resinous coating is released from
the support web. A ~uitable platen temperature to achieve
the above objects is in the range 330F to 420F, more
preferably between 340~F and 3~0F, for automatic
operation.
The transfer pad is heated to a surface temperature
around 100~ - 200F lower than the platen's
temperature. The heating of the transfer pad occurs as a
natural result of the label pick-up process whereby the
~5 pad at least indirec~ly contacts the heated p~aten. The
heated pad serves to maintain the adhesive/release layer
in a softened, tackified state and permits the eventual
release of the transfer substrate. An illustrative
temperature range is between about 150F - 300F. The
various temperatures are dependent on the mechanical
design of the transfer apparatus, and will tend to be
lower for a given label chemistry wi~h higher transfer
pressures and lower cycle speeds.
A preferred composi~ion for the transfer pad is an - -
elastomeric material. Silicone rubber has the advantagesof being easily m~lded in a variety of configurations, and
having suitable deformability as-known in the prior pad
transfer art. In the present invention, this material
enjoys the additional significant advantage of
withstanding the elevated temperatures which are
characteristic of the transfer process. A particular
property of some importance in the transfer of smooth,
glossy labels is that the pad surface have a relatively
smooth texture.
.
:1~22~34
As will be understood from the Eoregoing discussion,
according to -the invention there is provided a process for
transEerring a decorative laminate from a support to an article,
comprising the steps:
heating the laminate, which is comprised of a
nonwax-based adhesive/release layer in contact with the support,
and a design layer, to a first temperature above the melting
point of said adhesive/release layer, said laminate not having a
wax-based release layer intermediate said adhesive/release layer
and the support;
heating the surface of an elastomeric member to a
second temperature below said first temperature;
contacting the laminate under pressure with the heated
elastomeric member so that the laminate adheres to the
elastomeric member and separates from the support upon withdrawal
of said elastomeric member;
impressing the laminate against the article to bond the
adhesive/release layer thereto; and
withdrawing the elastomeric member from the article,
whereupon the laminate remains permanently adhered to the
article.
In a further aspect, is is provided that the time
interval between contact of the laminate against the article and
withdrawal of the elastomeric member from the article leaving the
laminate permanently adhered to said article is in a range
between abou-t 0.01 and 0.2 seconds.
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~226~3~
In a further aspect it is provided tha-t the
nonwax-based adhesive/release layer may comprise a polymerization
product of a diamine with a dimerized Eatty acid.
DESCRIPTION OF THE DRAWINGS
Other aspects of the invention will become more
apparent after considering several illustrative embodimen-ts of
the invention taken in conjunction with the drawings:
FIG. 1 is an elevated view of the decorative laminate
of the invention and the transfer pad before the transfer pad is
pressed onto the laminate.
FIG. 2 is an elevated view of the decorative laminate
of the invention and the transfer pad after contact is made
between the pad and the laminate and the support released.
FIG. 3 is an elevated view of the decorative laminate
of the invention with inclusion of a barrier layer.
FIG. 4 is an elevated view of the decorative laminate
of the invention without a protective coating layer.
FIG. 5 is an elevated view of the decorative laminate
of the invention without a protective coating layer and with
inclusion of a barrier layer.
DETAILED DESCRIPTION
A preferred embodiment of the decorative laminate of
the invention is shown in Figure 1. The decorative laminate 5 of
the invention is composed of a support 10, typically a substrate
composed of a paper sheet or web which is affixed at least on one
side to a transfer substrate 7. Transfer substrate 7 as best
shown in Figures 1 and 2, is preferably composed of a resinous
coa-ting layer 20, an ink layer 30 and a protective coating 40.
- 12(a) -
~1 ~2Z6i~'~
Optionally, as shown in Figure 3, the laminate 5 and substrate 7
may include a barrier layer 25 between ink layer 30 and resinous
coating 20.
Laminate 5 is formed by providing support 10 with a
nonwax-based adhesive/release resinous coa-ting 20 on at least one
side o:E support 10. The transfer substrate 7 of the present
invention excludes use of a wax-based release layer intermediate
the adhesive/release resinous coating 20 and support 10. The
adhesive/release resinous coating 20 is in direct contact with
support 10. Resinous coating 20 is overcoated with an ink layer
30 composed of letters or designs imprinted in ink. Ink layer 30
does not contact support 10. Ink layer 30 is in turn provided
with an overcoating of protective coating layer 40. The transfer
substrate 7 may also be provided with a resinous barrier coating
between ink layer 30 and resinous coatiny 20.
The barrier coating 25 illustrated in Figure 3 may
typically be of the same composition as protective coating 40 and
prevents absorption of the ink into the resinous coating 20. Use
of a protective coating layer 40 is particularly advantageous
when the container con-tents includes corrosive or abrasive
elements such as alcohol, cosmetics, toiletries, ~ood and dairy
products, beverages or frozen goods.
Alternatively, the protective coating layer 40 may be
omitted from the transfer substrate 7 as illustrated in Figures 4
and 5. Protective coating layer 40 may be omitted in labelling
applications, particularly wherein the transfer substrate 7 will
not be exposed to harsh
- 12(b) -
J.~2ZZ68
13
chemical6 or corrosive elements, for example when applied
to tags or containers holdin~ chemically inactive
material. In such case the transfer substrate 7 may be
composed of resinous coatin~ 20 overcoated with an ink
layer 30 as illustrated in Figure 4.
The transfer substrate 7 without a protective coating
layer is affixed to support 1~ as shown in Figure 4 to
form a decorative laminate 5. A barrier layer 25 may be
included between ink layer 30 and resinous coating 20 to
form a transfer substrate 7 as illustrated in Figure 5
which does not have a protective coating layer. Ihe
barrier layer 25 prevents absorption of the ink into the
resinous coating 20.
The laminate of the invention is particu~arly
suitable for use in automated processes. In the process
of the invention a support 10 typically in the form of a
weh carrying a plurality of transfer substrate 7 aligned
in sin~le rows are passed under a flexible transfer pad
50. ~he transfer pad 50, preferably composed of silicon
rubber and support substrate 10 are each first heated.
Transfer pad 50 is then pressed onto substrate 7 as it is
passed under the pad 50 so that the pad comes into contact
with the protective coating layer 40 or ink layer 30 if
the substrate 7 does not include a protective layer 40.
As the transfer pad 50 is w;thdrawn, substrate 7 adheres
to the pad and the suppoFt 1 0 separates from substra~e 7. --
Substrate 7 is then pressed onto an article so that the
resinous coating layer 20 contac~s the article. As the
transfer pad 50 is withdrawn it separate from substrate 7,
and substrate 7 adheres to the article. A permanent bond
between resinous coating layer 20 and the article then
forms. If substrate 7 includes a protective coating 40,
the ink design in ink layer 30 is distinctly visible
14
through protective coating 40 after su~strate 7 has been
transferred to the article. Protective coating 40 dries
to a smooth, glossy finish which protects ink layer 30
from the environment.
In the first step of the process, sufficient heat is
applied to the exposed surface of supp~rt 10, to heat the
substrate to a temperature which is above ~he melting
point of the resinous coating 20. Support 10 is heated to
a temperature t-ypically between about 50F to 150F
above the melting point of the resinous coating 20.
Typically, support 10 is heated to between about 330F
to 420F, more preferably 340F - 360F, so that the
protective coating 40 (or ink layer 30, if protective
coating is not included in substrate 7) becomes tacky, and
resinous coating 20 softens and begins to melt enough to
permit the support to be removed from transfer substrate
7. The rubber transfer pad 50, preferably composed of
silicon rubber, having a smooth contact surface is heated
to a temperature which is lower than the temperature to
?0 which support 10 is heated, preferably 100 to 20nF
lower than the temperature of support 10. Typically, the
transfer pad sn is heated to between about 150~ to
300F, more preferably 150F - 250F. The various
disclosed temperatures are dependent on the mechanical
characteristic~ of the transfer apparatus as well as the
label chem~stry and will genèrally be lower at higher
transfer pressures and lower cycle speeds.
Transfer pad 50 will be heated as a normal incident
of the transfer process, inasmuch as it will periodically,
at least indirectly, contact the n~eans for heating support
10. If this heating effect is insufficient in the context
of a given system, an independent heater should be
provided for pad 50.
~22~ 4
In a second step oE the process, as shown in Figure L t
the ho-t transfer pad 50 is pressed against laminate 10 so as to
make pressure contact with the protec-tive coating 40 or ink layer
30 in the event protective coating 40 is omitted. The transfer
pad is then withdrawn in a third step, as shown in Figure 2, at
which time coating 20 splits to separate from support 10 thus
releasing support 13. The coating 40 or ink layer 30 is
sufficiently adhesive that the subs-trate 7 adheres to the
transfer pad. Thus, the substrate 7 is left in adhesive contact
with the transfer pad 50 and resinous coating 20 is exposed to
the environment.
In a fourth step of the process, the hot transfer pad
50 and adhering substrate 7 is then pressed onto a surface of
either a flat or three-dimensional object including articles
having compound curves, irregular surfaces, or recessed panels so
that the exposed coa-ting layer 20 comes into pressure contact
with the article. The article may consist of any of a wide range
of materials including ceramic, plastic, or glass.
The time interval between steps three and four is
preferably less than about 1 second, more preferably between
about 0.01 to 0.2S second. With the preferred composition for
coating 20 disclosed in Table I, coating 20 will be sufficiently
tacky up to temperatures from about 150C to 300~C.
As coating 20 comes into contact with article 60, it
exhibits a tacky adhesive quality which is greater than the
adhesive force between substra-te 7 and transfer pad 50. Pad 50
is withdrawn from article 60 in a Eifth step of the process. The
time in-terval be-tween the moment of contact of substrate 7 with
- 15 -
:lZ;~;~684
the article and the moment oE withdrawal of pad 50 away from the
article is preferably less than about 1 second and as low as
about 0.01 second, preferably be-tween 0.01 and 0.20 second. Thus
the total time interval as measured from the moment of withdrawal
of the transEer pad 50 from support 10 to release transfer
substrate 7 from support 10 until the moment of withdrawal of
transfer pad 50 from the article leaving substrate 7 permanently
adhered thereto is preferably between about 0.02 and 0.45
second. The foregoing time intervals are most readily achieved
if transfer pad 50 is in the shape of a cylindrical roller.
Thus, as transfer pad 50 is withdrawn from article 60 substrate 7
remains in adhesive contact with the article. Coating 20 also
functions to permanently bond substrate 7 to the article as the
substrate is left to dry under ambient conditions. Thus, the
resinous coating layer 20 may be termed an "adhesive/release"
layer, in that it provides the unique dual functionality as a
release layer to permit separation of substrate 10 in one step of
the process, and ultimately as a permanent adhesive to bond the
ink layer 30 to an article.
As the substrate 7 cools on the article, protective
coating 40 when included in the substrate forms a hard,
protective lac~uer coating over ink layer 30 forming a chemical
and abrasion resistant protective layer, thus sealing the ink
layer from exposure to moisture vapor, oxygen, grease, and other
corrosive elemen-ts in the environment. The resulting laminate
has the property that the design~ which may be either a single or
multiple colored designr shows distinctly therethrough regardless
of the type of curva-ture of the surface to which it has been
~2;~684
applied and regardless of whether the article is composed oE
ceramic, glass, or plastic. Furthermore, the outline oE ~he
protective coating layer 40 or -the resinous coating 20 on the
article is essentially invisible to normal inspection.
The coating layer 20 and protective coating 40 remain
permanently affixed to article 60 as an integral part of the
transfer substrate. When coating 40 is not included in substrate
7, ink layer 30 is exposed directly to the environment. The
aEEixed substrate is not subjected to firing, but it should be
appreciated that if article 60 is composed of glass, an inorganic
Elux material may be
- 16(a) -
1~22
17
added to form ink layer 30. In thi6 case, if ~ubstrate 7
is exp~sed to high temperature firing, the organic lsyers
20 and 40 are volatilized leavin~ ink layer 30 fused to
- the article.
The preferred compositions of the respective layers
comprising the decorative laminate 7 are set forth as
follows with reference made to the accompanying tables:
, . . .
Support (10~:
The support 10 may be any support member or web to
hold imprint substrate 7 securely attached thereto.
~owever, it is preferable to have support 10 composed of a
paper sheet more preferably a paper sheet that is clay-
coated to improve its smoo~hness quality and to retard
penetration of the reino~s coatin~ 2n into the paper
1~ sheet as heat is applied to the back of ~he paper. The
paper sheet may be any type of paper preferably Kraft-type
'1, paper having a thickness of between about 2 to 2.5 mils
and a basis ~eight of hetween about 26 to 40 lbs./ream
(3~00 sq. ft. per ream3.
2n Resinous Coatin~ Layer (20):
Coating layer 2~ is preferably composed of a
p~lyamide resin having 2 softening point advantageously
be~ween about 96C - 105C. Ihe polyamide ~esin i~
p~eferably co~pose~ of the polymerization product o~ a
linear methylene diamine and dimerized fatty acid. A
polyamide resin which has been determined to be
particularly advanta~eous i~ the polymerization products
of hexamethy~ene diamine and dimerized linoleic acid, and
tetramethylene diamine and dimeri2ed oleic acid. Ihe
formulation shown in Table 1 is particularly suitable for
resinous coatin~ layer 20, since it has been discovered to
have the required release properties permitting the easy
.
1~
removal of substrate 1 n in one step of the process and
- ultimately as a per~anent adhesive to bond ink layer 30 to
article 60 in another step as discussed in ~he foregoing.
The resinous coating layer may alternatively be
composed of other materials such as polyterpenes, vinyl
toluene/alpha methyl styrene copolymers and ethylene vinyl
acetate copolymers.
The coating layer 20 i;s made preferably by admixing
the components shown in Ta~le I in the weight proportions
by weight indicated in Table I to form a polyamide
resinous so~ution. The mixture is prepared at ambient
temperature and utilizing conventional mixing equipment.
The preferred polyamide resin shown in Table I is
so]d under the tradename EMEREZ 1537 by Emery Industries
of Cincinnati, ~H. The polyamide resin EMEREZ 153' is the
polymerization product of the type above-mentioned,
namely, the product of a methylene diamine such as
hexamethylenediamine and a dimerized fatty acid such as
dimerized linoleic acid. It has a softening point between
110 to 120C, a ~iscosity at 160C of 3.5 to 5 DO
poise, a ~ardner color index (max.) of 4.~, an acid value
of 4.0 max., and density at 25C of ~.1 lbs./gal.
The resinous solution is typically prepared by
dissolving the polyamide resin EMEREZ 1537 in isopropyl
25 alcohol and toluene in the proportions indicated in Table
I and then modifying the resulting solution with about 4
to 16 percent by weight castor oil plasticizer and further
by the addition of 2 to ~ percent by weight of erucamide
(egO Kenamide E). The resulting polyamide resinous
30 dispersion has a typical preferred composition a~ set
forth in Table I.
Erucamide is a fatty amide of cis - 13 - decosenoic 3
acid sold under the tradename KENAMIDE E by Humko
Sheffield Chemical Div. of Kraftco Corp., Memphis, ~N.
':
.-
l 9
The erucamide additive permits the use of an
increased amount of castor oil p~asticizer which enhances
the fluidity of the resinous coating layer. The fatty
amide KENAMIDE-E has an average molecular weight of 335,
S an iodine value between about 70 to 80, a capillary
melting point of about 76 to 86C and a Gardner color
maximum of 5.
The polyamide resinous solution having a typical
composition illustrated in,~Table I may be applied to the
support 10 by any conventional printing methods, for
example, by gravure, silk screen, offset, or flexographic
printing methods. ~owever, the gra w re method is
preferred because better process print can be realized by
this method as well as better economy and color
consistency with long runs. After the coating is applied
to substrate 10 and dried, the solvents are evaporated and
- the resulting dried resinous coating (20) has a typical
preferred composition as shown in Table I.
The dried resinous coating (2~) covering support 10
has a basis weight preferably of between about 1.5 to 15
lbs./ream, more preferably between about 3 to 5 lbs./ream
(300n s~. ft. per ream) and has a melt viscosity in the
ran~e of 3.5 to 8.5 poise at 160C.
Ink Layer 30:
Ink layer 30 may be composed of any conventional type
of ink of any color including halftone colors. ~he inks
which are preferable have the property that they do not
soak into the resinous coating when applied without a
barrier layer. The present invention has the advantage
that multicolored inks can be used to produce a
multicolored design image, that is, multicolored design
images transferable in one pass.
A preferred ink is a polyamide-nitrocellulose ink.
In this type ink the polyamide is a dimerized fatty acid
' 1! 1
~222~84
2~
copolymerized with a linear diamine which constitutes
about ~0 weight percent of the ink and the remainder is
; essentially nitrocellulose. ~lternative inks having an
acrylic, polyester, or vinyl base may also be employed.
If a protective coating 40 is not included in
transfer substrate 7 as illustrated in Figures 4 and 5,
ink layer 30 is preferably composed of an isobutyl
methacrylate-type ink which exhibits suitable adhesive and
release characteristics to~allow substrate 7 to be
transferred to pad 50 and thence released therefrom as
substrate 7 is pressed onto an article. A preferred ink
of this type has been determined to be an ink having
isobutyl methacrylate binder modified with maleic rosin
and polyisoprene.
Protective Coatin~ ~ayer (40)
The protective coating layer 40 has a preferred
formulaticn shown in Table II. It is composed essentially
of a film-forming, multiaromatic, acid-based polyester
designated polymer (i) and a second reinforcing poly~er
(ii) which contains a bulky ring structure such as a
polyrnerized rosin ester. The reinforcing polyrner (ii)
desirably may constitute between about 20 to 50 weight
percent and preferably about 20 weight percent of the
dried protective layer (40). The polymers ti~ and (ii)
should be soluble in the sarne or miscible solvents, such
as toluene and methye~hyl ketone. Advantageously, the
polyrners (i) a~d (ii) may have a refractive index of about
1.5.
The multiarornatic acid-based polyester (Polymer (i))
is preferably composed of the reaction products of the
polymer condensation products of polyester forming
reactants of one or more glycols reacted with naphthalic,
or phthalic acids.
. .
2~;~4
21
A preferred polyester polymer (i~ is a ]inear
multiaromatic acid-based polyester such as that available
under the trademark VITEL PE200 or VITEL PE222 from
~oodyear Company of Akron, OH. The polyesters sold under
the above VITEL trademark are aromatic acid-based
polyesters having yellow, amorphous granules of Acid
Number from 1 to 10, preferably 1 to 4, a Shore nurometer
hardness of about 75 ~o 80 D, a specific gravity of about
1.25, and a ring and ball ~oftening point of about 150 to
170C.
A preferred reinforcing polyester polymer (ii) is a
rosin ester for~ed typically by reaction of polyhydric
alcohols, maleic anhydride or phenol aldehyde and rosin
acids such as abietic and pimaric acids. The rosin ester,
(Poly~er (ii)) is preferably composed of methyl abietate,
methyl hydroahietate, glyceryl hydroabietate, or ester
gum.
A preferred reinforcing polymer (ii) of this type is
sold under the trademark NEOLY~ 23-75T from ~ercules
Chemical Company of Wilmington, Delaware.
A preferred protective coating layer 40 is formed of
a polyester solution having the typical preferred
composition se~ forth in Table II. The polyester Tesinous
solution is prepared by admixing the constituents in the
proportions set forth in Table II utilizing conventional
mixing techni~ues. The polyester resinous solution is
coated onto ink layer 30 by conventional printing methods
such as by gra w re, silk screen offset, or flexographic
methvds. However~ the gra w re method is preferred because
better process print and sharper coloring can be realized
by this printing method as well as better economy and
color consistency with long runs.
~ Z Z 2 ~
After the coating is applied to ink layer 30 and
dried, the solvents are evaporated and the resulting dried
protective coating has a typical preferred composition as
shown in Table 11. The dried protective coating layer 40
has a basis weight preferably between about 0.5 to 3
lbs./ream (3000 sq. ft. per ream).
Additionally, the same preferred formulation above
described and as shown in Table II or the dried
protective coating layer 4~b may be used as an optional
barrier layer 25 between ink layer 30 and the resinous
coating layer 20. Ihe method of preparing the barrier
layer may also be the same as above-described for
preparing the protective coating 40 by utilizing the same
preferred polyester resinous solution formùlation
illustrated in ~able II. If a barrier coating is used,
the dried barrier layer between ink layer 30 and resinous
coating 20 typically has a basis weight of between about
0.5 to 3 lbs./ream. Inclusion of a barrier coating is
optional) but its use further protects ink layer 30 from
2~ having moisture vapor, oxygen, and grease absorbed to it
through resinous coating 20.
Transfer Pad 50:
The transfer pad is preferably composed of silicone
rubber. It has been found to be advantageous to provide
2~ the silicone rubber pad with a smooth surface and a convex
curvature facing transfer substrate 7 so that the transfer
sub~trate 7 has a smooth, glossy surface after it has been
transferred to the article. Any commercially available
room temperature or heat curable silicone rubber may be
suitable to make the pad. For example, the pad may be
formed by casting room temperature vulcanizable silicone
rubber with a suitable curing agent in propurtion
typically of 10 parts by weight silicone rubber to 1 part
,,
~22
23
by weight curing agent. A suitable room temperature
vulcanizable silicone rubber can be purchased under the
tradename RTV 700, and the curing agent under the
: tradename B~TA 5, both available from General ~lectric
Company of Pittsfield, MA. ~he cast silicone rubber pad
product preferably has a Shore A hardness of about 4 to
: 35.
~Z6~9
24
T A B E E
POLYAMIDE RESINOUS SOLUTION:
_ercent by Wei~ht
Polyamide Resin
~eg. EMEREZ 1537) 25.5
Solvent 1
Isopropyl Alcohol 49.0
Solvent 2
~oluene . _21 . Q
P]as~icizer
- Castor ni~ 3.0 _
Erucamide
(eg . KEI~AMIrlE E) _1 . 5
1 00 .0
DRIED RESINOUS COA~IMG (20):
Polyamide Resin
Seg. EMEREZ 1537) 85.0
. Plasticizer
; Castor Oil 10.0
Erucamide
(eg. KENAMInE E) ~.0
1 00 .0
.
J
~22Z6~1
T A B L E II
POLYESTER RESINOUS SOLUTION:
Percent by Wei~ht
Polyester Polymer (i)
(eg. VITEL PE-200 or
VITEL PE-222) ,~ .20.0
Reinforcing Polyester Polymer (ii)
(eg. NEOLYN 23-75 T) 5.0
Solvent
Methylethyl ketone 75.0
1 00
DRlED PROTECTIVE LAYER (40)
Po]yester Polymer ~i)
(eg. VITEL PE-200 or
VITEL PE-222) ~0.0
Polyester Polymer (ii~
(eg. NEOLYN 23-75 T) 20.0
100.0
:~2;~6~34
Examples of the process of the invention and
preferred method of making the product are given as
follows
EXAMPLE I
A support 1~ in the form ~f paper web carrying a
multiplicity of transfer substrates 7 ali~ned in single
rows were passed under a silicone rubber transfer pad 50
having a smooth surface. ,!An automatic conveyer ~as usefl
to pass the transfer substrates 7 to and under the
transfer pad 50. The paper web was composed of Kraft-type
paper having a basis weight of between about 20 to 40
pounds per ream and the substrate 7 was made in accordance
with the specification set forth in Exampl~ II. As the
paper web (support tO) passed along the conveyor, the
support 10 was heated to a temperature of about 350F.
At this temperature level the protective-coating 40 became
tacky and the resinous coating softened and began to
melt.
The silicone transfer rubber pad 50 was heated to
between ab~ut 200 to 250F. As each heated substrate 7
in turn passed under hot transfer pad 50, the smooth
surface of the transfer pad made pressure contact with
protective coatin~ 40 in an automatic operation. ~s
transfer pad 50 was withdrawn, the resinous coating 20
partially separated from supp~r~ 10, thus releasing
substrate 7 from support 10 exposing coating 20 to the
environment, with coating 40 adhered to the ~ransfer pad.
The transfer pad ~0 and adhering substrate 7 was then
pressed onto the surface of an article 60 which was
conveyed to the vicinity of the transfer pad. Article 60
was comprised of a polyethylene, and had compound curves
and irre~ular 6urfaces.
6~34
27
The time interval between the moment of release of
substrate 7 from s~pport 1~ to the moment of contact of
substra~e 7 with the article was about one second.
As the transfer pad 50 was withdrawn from article 6~,
substrate 7 remained in adhesive contact with the article
in a permanent bond hetween the resinous coating layer 20
and the article. The ink design in ink layer 30 was
distinctly visible through protective coating 40 after
substrate 7 had been trans~erred to the article. Upon
cooling, protective coating 40 developed a smooth, glossy
finish protecting ink layer 30 from the environment. The
time interval between the moment of contact of substrate 7
~ith article 60 and the moment of withdrawal of pad 50
away from the article was about 0.5 second.
The paper web (support 10~ which was affixed with the
remaining substrates 7 was conveyed automatically under
transfer pad 50~ As each substrate 7 in turn passed under
the transfer pad, the above-described sequence was
repeated to ~ranspose a substrate 7 from the web to
another article. The process was repeated automatically
until all the artic]es on the assembly line were imprinted
with a substrate 7.
EXAMPL~ II
A web of support 10 composed of Y.raft-type pape~
~5 sheet having a basis weight of about 26 to 40 lbs.~ream
was fed through a gravure printer. The resin~us coating
(20) is formed over predesignated portions on the paper
sheet by utilizing conventional gravure printing to apply
the polyamide resinous solution to the paper sheet.
The polyamide resinous solution may be prepared in
accordance with the formulation set forth in Table I as
described in the foregoing. To facilitate the application
2689L
~ ,
of the resinous solution, it may be diluted further with
solvent as desired preferably so that its viscosity is
about 25 sec. as ~easured with a ~4 Ford cup. As the
paper web was passed through the gra w re printer, a
- 5 coatin~ of the polyamide resinous solution was uniformly
applied to cover predesignated portions on a side of the
paper sheet.
The coated paper was then passed through a
conventional convective coater dryer -wherein the coating
is dried at about 200 to 250F evaporating the
solvents and producing a dried resinous coating layer (20)
having a composition typically as shown in Table I and a
basis weight of between about 1.5 to 15 lbs./ream (3000
sq. ft./ream).
The dried web was then passed in sequence through a
gra~re printer wherein the neAt layer, eg., ink layer 30
cornposed of isobutylmethacrylate ink modi~ied with maleic
rosin and polyisoprene was applied over the dried resinous
coatin~, A single ink color or multicolored inks
including halftones may be applied to produce an imprint
design or any number of colors. The substrate overcoated
with ink layer 30 was further passed sequentially to
conventional convective drying carried out at about 200 to
250F to dry the ink.
Ihe dried substrate was then a8ain passed through a
grawre printer wherein the polyester resinous solution
was applied over ink layer 30. A polyester resinous
solution was then applied in accordance with the
formulation set forth in Table II as described in the
foregoing. However, to facilitate application of this
solution by gra w re imprinting, the solution was first
further diluted with solvent to yield a viscosity of about
20 seconds as measured with a ~4 Ford cup.
:~2~ 68
29
The substrate overcoated with the polyester resinous
solution was dried in conventional convective coater
dryers operatin~ at about 200F to 250F until the
polyester resinous solution dried to form a dried
protective layer 40 having the typical preferred
composition shown in Table II, and a basis weight of
between about 0.5 to 3 lbs.~ream~
~~PLE III
A label-bearing web was produced as in Example II
' 10 with the following modification. Prior to applying ink
layer 30, the substrate overcoated with dried resinous
coating 20 was passed through a gravure printer in order
to apply a barrier coating 25 over ink layer 3n. The
harrier coa~ing,25 was compose~ of the same polyes~er
resinous so~ution shown in Table II. The barrier coating
was dried in conventional convective coater driers at
about 200F to 250F, forming a barrier having
typically the same composition as that of the dried
protective layer 40 set forth in Table II and a basis
weight between about 0.5 to 3 lbs./ream. Thus, the
' substrate 7 was formed of a coating layer 20, optional
barrier layer 25, ink layer 30 and dried protective
coating 40.
ln practice, rows of individual substrates 7 may be
printed onto support substrate 10 in mass production
automated fashion.
EXAMPLE IV
The process of the invention was carried out in
accordance with Example II and the laminate 5 and
substrate 7 were manufactured as set forth in Example II
except that ink layer 30 was not overcoated with
, . .
iZ2~68
3n
protective coating 40. Instead substrate 7 was formed as
illustrated in Figures 4 or 5 with the free surface of ink
layer 3n exposed. Thus, in the process of the invention
as transfer pad 50 was pressed onto substrate 7 the pad
made direct contact with the exposed surface of ink layer
30 and after substrate 7 was transferred to article 60 the
free surface of ink layer 30 was left exposed to the
environment. In accomplishing this embodiment of the
invention, ink layer 3~ was formed by employing an ink
formed of conventional pigment, a binder solvent, and a
binder composed of a film-forming isobutyl methacrglate
ink modified with maleic rosin and polyisoprene. The
isobutyl methacrylate was present in the hinder in an
- amount between about 60 to 80 percent by weight of the
binder, the maleic rosin between about 15 to 25 percent by
weight and the polyisoprene between about 5 to 15 percent
by weight of the binder. A typical preferred binder used
in forming ink layer 30 was composed of 70 parts by weight
isobutyl methacrylate modified with 20 parts by weight
ma~eic rosin and 10 parts by weight polyisoprene. The ink
layer 30 was coated onto resinous coating 20 or
alternatively onto barrier layer 25 and dried in the
manner set forth in Example Il to form the substrate 7
illustrated in Figures 4 and 5 ~espectivel~ e dried
ink layer 3~ had a basis weight of between about 0.5 to 2
lbs./ream.
lt was found that the ink layer 30 in this embodiment
exhibited the required adhesive characteristics to permit
transfer of substrate 7 to transfer pad 50 and thence to
article 60 when the process of the invention was carried
out as set forth in ~,xample I. Upon transfer of substrate
7 onto article 60, the ink design in ink layer 30 was left
indelibly imprinted on article 60. Ink layer 30 exhibited
!
1~2684
abrasion and corrosion resisting properties sufficient to
permit a variety of applications, particularly where
article 60 contains chemically inactive and nontoxic
components and where article 60 is not intended to come
into contact frequently with highly abrasive materials.
Although the transfer~substrate 7 is removed from
substrate 10, transferred to heated pad 50 and then to the
desired article within the context of an automated process
in the foregoing description, it should be appreciated
that other variations including manual transfer of
substrate 7 are also within the scope of the present
invention. The preferre~ substrate compositions disclosed
herein admit suitable substitutions for the various
components, within the scope of the adhesive/release
laminate and the process for transferring this laminate to
articles. The invention, therefore, is not intended to be
limited to the description in the specification but only
by the claims and equivalents thereof.
