U.S. patent number 3,907,974 [Application Number 05/413,908] was granted by the patent office on 1975-09-23 for curable decorating systems for glass or metal containers.
This patent grant is currently assigned to Dennison Manufacturing Company. Invention is credited to Donald R. Smith.
United States Patent |
3,907,974 |
Smith |
September 23, 1975 |
Curable decorating systems for glass or metal containers
Abstract
A method of and articles for decorating heat resistant surfaces
such as glass or metal using a heat transfer decoration comprising
in sequence a temporary carrier, a transfer lacquer layer which is
removably adhered to the surface of said carrier, at least one
design print layer adhered over the lacquer layer and a
heat-activatible adhesive layer adhered over said design print
layer wherein at least the transfer lacquer and design print layers
contain cross-linkable resin means and a cross-linking agent for
cross-linking the resin intralayer and interlayer to form a unified
adherent decoration resistant to abrasion and chemicals. The metal
or glass surface may optionally be coated with a cross-linkable
primer composition prior to application of the heat transfer
decoration thereto.
Inventors: |
Smith; Donald R. (Dover,
MA) |
Assignee: |
Dennison Manufacturing Company
(Framingham, MA)
|
Family
ID: |
23639160 |
Appl.
No.: |
05/413,908 |
Filed: |
November 8, 1973 |
Current U.S.
Class: |
428/346; 156/240;
428/349; 428/429; 428/914; 156/249; 428/352; 428/420; 428/450 |
Current CPC
Class: |
B44C
1/1712 (20130101); Y10T 428/31612 (20150401); Y10S
428/914 (20130101); Y10T 428/2839 (20150115); Y10T
428/2813 (20150115); Y10T 428/2826 (20150115); Y10T
428/31536 (20150401) |
Current International
Class: |
B44C
1/17 (20060101); B44C 001/16 (); B41M 003/12 ();
B32B 007/10 () |
Field of
Search: |
;117/3.2,3.4,1.5
;161/167,188,406,413,184,190,257,193,207
;156/230,240,249,237,241 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Ansher; Harold
Attorney, Agent or Firm: Thompson, Birch, Gauthier
Samuels
Claims
I claim:
1. A stable heat transfer decoration comprising in combination a
temporary carrier having a release surface from which the transfer
is readily releaseable at elevated transfer temperature, and
removably adhered to said surface in sequence a transfer lacquer
layer, at least one design print layer, and a heat-activatable
adhesive layer, wherein at least said transfer lacquer and design
print layers adjacent to and in contact with each other contain
cross-linkable resin means for forming cross-linked polymers, at
least one of said two adjacent layers containing cross-linking
agent means for cross-linking with said resin means in both layers,
said agent means being stable at room temperature and activatable
at elevated temperature to cross-link with said resin means within
said one layer and between the two contacting layers, said resin
and agent means being present in amounts effective to increase the
abrasion and chemical resistance of the transfer decoration after
application to a receiving surface and activation at elevated
temperature.
2. The heat transfer of claim 1, in which said agent means reacts
to form cross-links at a temperature between about 200.degree.F and
450.degree.F.
3. A heat transfer according to claim 2 wherein said one layer
containing the cross-linking agent means is the design print
layer.
4. A heat transfer according to claim 3 wherein all three layers
including the heat-activatable adhesive layer contain
cross-linkable resin means with which said agent means reacts at
elevated temperature to form crosslinks.
5. A heat transfer according to claim 2 wherein each of said layers
contains cross-linkable resin means, and the transfer lacquer and
heat-activatable adhesive layers each contain cross-linking agent
means activatable to form cross-links at elevated temperature with
the resin means in the design print layer.
6. A heat transfer according to claim 4 wherein each of said layers
contains cross-linkable resin means and cross-linking agent means
activatable to form cross-links within the layer and interlayer at
the interface with the adjacent layer, whereby all layers are
cross-linked together upon transfer and activation at elevated
temperature.
7. A heat transfer according to claim 6 wherein said agent means
are selected from the group consisting of blocked polyisocyanates,
urea-formaldehyde resins and polyepoxide resins.
8. A heat transfer according to claim 2 wherein the cross-linkable
resin means in the transfer lacquer layer is a cellulosic material
containing sufficient hydroxyl substituents for cross-linking, and
said transfer layer also contains a blocked polyisocyanate as said
cross-linking agent means.
9. A heat transfer according to claim 6 wherein said release
surface is the surface of an inert thermoset resin, said
cross-linkable resin means in the transfer lacquer layer is a
cellulosic material having sufficient hydroxyl substituents for
cross-linking, said cross-linking agent means in the transfer
lacquer layer is a blocked polyisocyanate, said resin means in said
design print layer has sufficient hydroxyl substituents for
cross-linking, said cross-linking agent means in the design print
layer is a urea-formaldehyde resin, said resin means in the
adhesive layer contains sufficient carboxyl substituents for
cross-linking, and said cross-linking agent means in the adhesive
layer is a polyepoxide resin.
10. A heat transfer according to claim 9 wherein said cellulosic
material is cellulose acetate.
11. A heat transfer according to claim 9 wherein said cellulosic
material is a cellulose ester, said resin means in the design print
layer is a hydroxyl modified copolymer of vinyl chloride-vinyl
acetate and said resin means in the adhesive layer is a carboxyl
modified copolymer of vinyl chloride-vinyl acetate.
12. The method of decorating a heat resistant surface of glass or
metal comprising the steps of transferring to said surface from a
release surface of a temporary carrier, under and heat and
pressure, a decoration comprising in sequence a transfer lacquer
layer, at least one design print layer, and a heat-activatable
adhesive layer which is non-tacky at room temperature, wherein at
least said transfer lacquer and design print layers adjacent to and
in contact with each other contain cross-linkable resin means for
forming cross-linked polymers, at least one of said two adjacent
layers containing cross-linking agent means for cross-linking with
said resin means in both layers, said agent means being stable at
room temperature and activatable at elevated temperature to
cross-link with said resin means within said one layer and between
the two contacting layers, immediately stripping the temporary
carrier from said layers, and curing said resin and agent means in
said layers at a temperature between about 200.degree.F and about
450.degree.F to form a cross-linked structure within and between
said layers, whereby an adherent cross-linked decoration is
provided with improved resistance to abrasion and chemicals.
13. The method according to claim 12 wherein each of said layers
contains both said resin means and agent means and wherein said
heat-resistant surface of said metal or glass is coated with primer
means having cross-linkable substituents reactive at elevated
temperature with the agent means in said adhesive layer, whereby
all of said layers, after curing, are cross-linked together and to
said primer.
14. The method according to claim 13 wherein said primer is a
silane, said release surface is an inert thermoset resin, said
resin means in the transfer lacquer layer is a cellulose ester
having sufficient hydroxyl substituents for cross-linking, the
agent means in said transfer layer is a blocked polyisocyanate,
said resin means in the design print layer has sufficient hydroxyl
substituents for cross-linking, said agents means in the design
print layer is a urea-formaldehyde resin, said resin means in the
adhesive layer has sufficient hydroxyl or carboxyl substituents for
cross-linking, and said agent means in the adhesive layer is a
polyepoxide resin.
15. A decorated article of glass or metal comprising primer means
on a surface of said article and a heat-transferred organic
decoration comprising an adhesive layer over said primer means, at
least one design print layer over said adhesive layer, and a
protective transfer lacquer layer over said design print layer, all
of said layers comprising polymeric resin means, all of said resin
means and primer means being cross-linked intralayer and interlayer
to form a unified adherent decoration resistant to abrasion and
chemicals.
16. A decorated article according to claim 15 wherein said primer
is a silane, said resin means in the transfer lacquer layer is a
cellulose ester having cross-linked hydroxyl substituents, said
resin means in the design print layer has crosslinked hydroxyl
substituents, and said resin means in the adhesive layer has
hydroxyl or carboxyl substituents cross-linked to said primer means
by means of a polyepoxide resin.
Description
This invention relates to heat transfers for labeling and
particularly to high quality, multi-color, chemically resistant
decorations for glass, ceramic, metal, or heat stable plastic
surfaces.
The art of heat transfer decorating is very old. It is described,
for example, in an early U.S. Pat. No. 1,030,908 to McKerrow, which
describes a heat transfer label having a paper backing, a transfer
layer of resin or wax, and a design of printing and coloring upon
the transfer layer. The transfer layers of McKerrow and those who
followed, as illustrated by U.S. Pat. Nos. 1,331,581, 1,882,593,
2,219,071 and 2,667,003, have not been entirely satisfactory for a
number of reasons.
Improved heat transfer labels based upon the use of oxidized waxes
as a release layer are in substantial commercial use and are
disclosed in U.S. Pat. No. 2,862,832 to Shepard, which discloses a
heat transfer label comprising a wax release layer on a suitable
carrier, an ink layer on the wax release layer, and a
heat-activatable thermoplastic adhesive layer over the ink layer.
Though such a heat transfer label is in considerable commercial
use, there are certain disadvantages associated with it. For
example, upon transfer to clear, transparent surfaces such as
plastic and glass, a portion of the molten wax release layer is
transferred along with the label. Upon solidifying, this wax
coating, present as a "halo" around the design print, appears
cloudy over clear areas and detracts from the appearance of the
design print.
Other transfer labeling specifically for glass and for ceramics and
of more recent origin include as typical examples the "water slide
off" type decal wherein the design print is derived from ceramic
type inks ultimately fired into the glass or ceramic article, as
described, for example in U.S. Pat. No. 3,015,574 to J. Gobel.
Labeling techniques employing direct dry heat transfer and
subsequent firing of the ceramic inks are also known, as shown, for
example in Canadian Pat. No. 919,521 to R. A. Keeling et al.
Similarly, solvent activated types of labels have been described,
wherein release assistance is provided by solvent activation
through the carrier sheet or web (U.S. Pat. No. 3,298,850, K. J.
Reed et al), or by direct activation of the adhesive layer by heat
and/or pressure upon microencapsulated solvents (U.S. Pat. No.
3,728,210, J. Piron). Finally, as another general type of the
decalcomania class is the precision die cut design print with a
pressure sensitive adhesive transfer layer, as shown for example in
U.S. Pat. No. 3,297,508.
All of the above techniques for transfer decorations on heat
resistant bases such as glass, ceramics, or metal suffer from a
variety of disadvantages, most notable of which are the lack of
chemical, abrasion, and rub resistance when the design print and
adhesive are plastic, due in part to insufficient adhesion and
cohesion between and within the various layers of the transfer
label, and, when the design print is based on ceramic inks, which
have limited color availability, lack of high quality multi-color
designs.
Accordingly, it is an object of the present invention to provide a
stable heat transfer label for heat resistant bases.
It is a further object of the invention to provide a chemical,
abrasion, and rub resistant transfer label for heat resistant
bases.
It is still a further object of the invention to provide a high
quality multi-color design print, preferably printable by roto
gravure, as part of the heat transfer label.
I have discovered that by employing in one or more of the layers of
the transfer label certain polymerizable crosslinking agents which
are capable, preferably in response to heat, of crosslinking the
resins in adjacent layers to form strong, cohesive interlayer
chemical bonds, chemical, abrasion and rub resistance are greatly
increased, and highly resistant multicolored transfer labels are
obtained. In a preferred embodiment, crosslinking occurs both
interlayer and intralayer, resulting in a cured label which is
thermoset throughout its thickness from the outer surface of the
transfer layer right to and including the surface of the heat
resistant base to which it is applied. In that embodiment not only
are the cohesion and abrasion resistance of the label much better
than previously available, but also the label is rendered
essentially temperature insensitive, so that glass, ceramic or
metal containers bearing the thermoset label can be subjected to
high temperatures without deleterious effects on the label's
properties.
The present invention can be used with particular advantage in
multilayer decorative transfer labels such as those disclosed in
copending U.S. Pat. application Ser. No. 244,292, filed Apr. 14,
1972, by B. Asnes, incorporated herein by reference. In that
application a heat transfer label system is described which
comprises an adhesive layer, laid down and adhered to a design
print, which has been laid down and adhered to a transfer lacquer
layer, (first down lacquer), which has been laid down and
releasably adhered to a release layer, which layer may or may not
have a backing sheet or layer adhered to it. The transfer lacquer
layer is preferably a clear cellulosic resin, such as a cellulosic
ester, having a softening point well above 300.degree.F to
450.degree.F, i.e. a cellulosic resin which does not appreciably
soften or tackify at transfer temperatures. The design print layer
is made up of one of more colors of conventional heat transfer inks
such as nitrocellulose and/or polyamide inks, containing dispersed
or dissolved therein pigments and/or dyes of the colors desired.
The last down adhesive layer is made up of a conventional
heat-activatable adhesive, suitable adhesives being disclosed
therein.
The term "crosslinking agent" is used to designate a material which
chemically reacts, e.g. polymerizes, with crosslinkable
polymerizable material to form chemical bonds, i.e. crosslinkages,
between the polymer molecular chains of that material or between
the polymer molecular chains of that material and a different
material. The "different" material may include polymer chains or
parts of chains of the crosslinking agent itself, i.e., during
polymerization the crosslinking agent itself may form polymer
chains which may be themselves crosslinked by the crosslinking
agent and/or crosslinked with another or other crosslinkable
materials by the crosslinking agent. The preferred embodiment
utilizes several polymeric crosslinking agents which react with
polymeric crosslinkable materials. The term crosslinking as used
herein includes the formation of chemical bonds between the chain
of the crosslinking agent and/or the chains of one or more
crosslinkable materials. In fact, both the crosslinkable material
and the crosslinking agent take an active part in any reaction
which occurs between them, and the term "crosslinking agent" is
used more or less to conveniently designate the more reactive of
the two materials. Indeed, some materials are suitable as both the
crosslinkable material and the crosslinking agent, e.g., those
polymers which undergo substantial crosslinking with themselves at
elevated temperatures.
Crosslinking agents suitable for use in accordance with the
invention are well known in the art. Choice of a particular
crosslinking agent depends upon which layer it is to be used in,
and the nature of the material in the adjacent layer, or layers, it
is desired to crosslink. If the crosslinking agent is used in the
first down or transfer lacquer layer, it must not reduce the
release properties of the lacquer/release layer interface.
Accordingly it should have a sufficiently high melting point to
keep from becoming soft or tacky at the temperatures at which the
label will be transferred, lest it adhere to the release layer and
interfere with release. Also, it should not crosslink or otherwise
be reactive with the material in the release sheet, which would
also prevent good release. If the crosslinking agent is used in the
adhesive layer, it must not interfere with the necessary adhesive
properties of that layer.
Where the layer with which crosslinking is desired contains
polymeric materials with available reactive groups, such as
carboxyl or hydroxyl groups, for example the cellulosic materials,
suitable crosslinking agents include those having blocked
isocyanate groups, epoxy groups, urea formaldehyde groups,
including substituted urea formaldehyde groups, primary and
secondary amines and polyamines, and other materials known in the
art. Crosslinking will also occur between materials having
available urea formaldehyde groups and materials having available
epoxy groups; between materials having available urea formaldehyde
groups and materials having available carboxyl groups; between
"blocked" isocyanates and materials containing epoxide groups; etc.
Generally, crosslinking agents suitable for crosslinking particular
polymeric materials are known to those skilled in the art, those
dealt with herein being only exemplary.
By "blocked" isocyanates is meant reaction products of isocyanates
with active hydrogen containing compounds which result in an
addition product having only limited thermal stability. These
compounds are stable at room temperature, but react at elevated
temperatures as if an isocyanate were present. Suitable blocked
isocyanates are known in the art, as disclosed for example in
Sanders & Frisch, Polyurethanes, Chemistry & Technology,
Vol. 1, pp. 118-21 (1962). Suitable blocking agents include those
disclosed therein, such as the phenols, substituted phenols, alkyl
and aryl mercaptans, and other compounds having reactive hydrogen,
such as the alcohols. Commercially available blocked isocyanates
suitable for use in the present invention include a variety of
Aminimides available from Ashland Chemical Co., especially Ashland
Aminimide 21001 (bis (trimethylamine) sebacimide) and Ashland
Aminimide 20603 (Bis (dimethyl-2-hydroxypropylamine) adipimide),
and a caprolactam blocked polymeric isocyanate available under the
mark Isonate 123P from the Upjohn Company.
In a preferred embodiment, material containing blocked isocyanate
groups is used as a crosslinking agent in the transfer lacquer
layer of a multi-layer decorative label, and the adjacent design
print layer contains a polymeric material containing available
hydroxyl groups. Preferably, the transfer lacquer layer also
contains a polymeric material having available hydroxyl groups. Use
of the blocked isocyanate crosslinking agents in the transfer
lacquer layer is especially advantageous because their reactivity
is generally low enough to minimize the likelihood of reaction with
the release layer, yet at elevated temperatures they readily
crosslink with materials having available hydroxyl groups.
Suitable polymers having available hydroxyl groups include known
polyols, such as cellulose and modified cellulosic materials such
as cellulose esters, including cellulose acetate, cellulose
propionate, cellulose acetate butyrate, etc., substituted
cellulosic materials such as hydroxyalkyl cellulose; starches, both
unmodified and modified; polymeric resins based on alcohols, such
as polyvinyl alcohol, or on monomers having a plurality of hydroxyl
groups, such as diols and glycols; and other polyols well known in
the art. It is preferred to use a cellulosic material as the source
of hydroxyl substituents in the transfer lacquer layer, preferably
cellulose esters such as cellulose acetate.
The amounts of the reactive components included in the various
layers can vary considerably, depending upon the particular types
of materials used and the properties desired of them in use. The
transfer lacquer layer, for example, may be predominantly made up
of crosslinkable material, such as the cellulose ester, and contain
a relatively small amount of a crosslinking agent, such as the
blocked isocyanates. Thus it may contain from about 80 to about 99
percent by weight cellulose acetate or other cellulosic material
and from about 0.5 to about 20 percent by weight blocked
isocyanates. Preferably that layer contains about 85 to 95 percent
by weight cellulose acetate or other cellulose ester and between
about 5 to about 15 percent polyisocyanate material. Other
materials may also be incorporated in the transfer lacquer layer,
such as a small amount of a tracer compound which is normally
colorless but fluoresces under the influence of ultraviolet
radiation. The tracer compound is useful in the printing process to
facilitate the registration of clear lacquers.
In those layers which are separated from the release layer by the
transfer lacquer layer or other layers, the reactivity and physical
characteristics are not as critical as they are in the transfer
layer, since adherance to the release layer is not a problem. Thus,
those layers may be formulated with a view to optimizing both
intralayer cohesion and interlayer adhesion. The adhesive bond
between layers in the decoration of the present invention may be
referred to as a cohesive bond or cohesion, since the crosslinking
which occurs between the materials in adjacent layers in effect
creates an interlayer blend of chemically linked material. Thus, in
layers other than the transfer lacquer layer, materials can be used
which are much more reactive than those used in the transfer
lacquer layer. For example, more reactive crosslinking agents such
as urea formaldehydes or epoxy materials can be used in the design
print and adhesive layers. In a preferred embodiment the design
print layers contain both a crosslinkable material, such as a
material having available hydroxyl groups, and a crosslinking
agent, such as a urea-formaldehyde resinous material. The relative
amounts of each can be about the same, or either may predominate.
Preferably the design print layers contain from about 30 to 55
percent by weight polyol and from about 40 to 65 percent by weight
heat reactive urea formaldehyde binder. The preferred urea
formaldehyde polymers or pre-polymers are substituted
ureaformaldehydes, such as butylated urea formaldehyde material.
The polyol in the design print layers is preferably a hydroxyl
modified vinyl resin, a hydroxyl modified vinyl
chloride-vinylacetate copolymer being most preferred. The design
print layers will also contain the pigments necessary for the
desired color, and minor amounts of other additives known in the
art may be added.
Where the adhesive layer is crosslinked with its adjacent print
layer, in accordance with the invention, it must both act as an
adhesive to bind the decoration to the glass, ceramic, metal or
other substrate, and serve as a crosslinked, integrated layer in
the finished decoration. Preferably it is a heat activatable
adhesive, and the same materials which make it a heat activatable
adhesive also participate in the crosslinking between the adhesive
layer and the adjacent design print layers. Again, these may
comprise one or more crosslinkable materials and one or more
crosslinking agents. In a preferred embodiment, the crosslinkable
material in the adhesive layer comprises a carboxyl modified vinyl
resin, and the adhesive layer further comprises two epoxy type
crosslinking agents: an epoxy modified vinyl resin and a highly
reactive diglycidyl ether-bisphenol A type of polyepoxide. Other
additives may also be included, such as a small amount of an
ultraviolet radiation absorber, which permits the adhesive layer to
be easily distinguished from the transfer lacquer layer during
printing. Again, the amounts required of the various ingredients
depend upon the particular ingredients used in the system. The
preferred embodiment contains between about 35 - 60 percent of the
epoxy modified vinyl resin, from 1 to 15 percent of the diglycidyl
ether-bisphenol A polyepoxide, and from 35 - 60 percent of the
carboxyl modified vinyl resin.
In practice, the decorative label is made by forming a suitable
release layer, as, for example, in the manner described in the
above mentioned co-pending U.S. Pat. application Ser. No. 244,292
by B. Asnes. Once the release layer is formed, the transfer lacquer
layer is applied onto the release layer, preferably by roto gravure
printing. The design print and adhesive layers are thereafter laid
down sequentially over the transfer lacquer layer, also preferably
by printing techniques.
In applying the finished decorative label to the substrate it is
greatly preferred if the substrate is first treated with any of the
well known silane adhesion promoters. Such materials include epoxy
silanes (e.g., A-187, from Union Carbide) mercapto silanes (e.g.,
A-189, also from Union Carbide), and others. It is generally
preferred to pre-heat the substrate before application of the
decorative label. Generally, pre-heating temperatures from about
150.degree.F to about 250.degree.F have been found to be
advantageous. After pre-heating, the decorative label is put in
contact with the heated substrate and heat and pressure are applied
to the temporary backing which supports the release layer, to
effect pressing of the adhesive layer against the substrate
surface. This is accomplished in a heat transfer decorating
machine, preferably the Dennison TD1B Decorating Machine, described
in several U.S. Patents including U.S. Pat. Nos. 2,862,832,
3,064,714, 3,231,448 and 3,261,754, or its equivalent. After
transfer, the decorated substrate is heat cured, e.g. for 10 to 20
minutes at about 200.degree.-300.degree.F, and then it may be
further heat cured, e.g., for 10 to 20 minutes at about
350.degree.-450.degree.F.
Upon curing, a very attractive, clear and precise decorative label
which is very strongly bonded to the substrate and has excellent
abrasion resistance is produced.
The benefits provided by the present invention are outstanding. The
applied decorative labels are far superior in durability, abrasion
and mar resistance, ease of application and appearance to heat
transfer labels previously known. One of the most important
advantages obtained through the present invention is the increase
in decorating speed. With even the most efficient of comparable
previous systems, the labeling speeds were limited to about 20 or,
at most, about 30 bottles per minute. Speeds of between 60 and 100
bottles per minute have been achieved using the present invention,
with the decorated bottles having the improved appearance, chemical
and abrasion resistance previously mentioned.
While it is preferred that a number of crosslinking and/or
crosslinkable materials be used to obtain the reactions between
adjacent layers, benefits can be derived from much simpler systems
in accordance with this invention. Thus, for example, a two
component reactive system might be used in which the same
crosslinking agent, for example, a blocked isocyanate material, is
contained in both the transfer lacquer layer and in the adhesive
layer, and reacts from both directions with a single crosslinkable
material in the design print layer, e.g., a polyol. The same agents
would also work if the crosslinking agent were in the design print
layer and the crosslinkable materials are in the transfer lacquer
and adhesive layers.
It is also preferred that each layer contain both a crosslinkable
material and a crosslinking agent. In this way the intralayer
cohesion is improved by crosslinking between the materials within
each layer; and the interlayer cohesion, and thus the overall
cohesion of the label, is improved by the action of the
crosslinking agents in both adjacent layers. In effect, the
decoration becomes thermoset, both throughout each layer and
between layers, as discussed above. However, some benefit is
obtained even when one or more of the layers contains only one of
the reactive materials, whether it be a crosslinkable material or a
crosslinking agent.
To summarize the most preferred embodiment, all of the transfer
lacquer layer, the design print layer or layers and the adhesive
layer contain both crosslinkable and crosslinking materials. In the
transfer lacquer layer the preferred crosslinkable material is
cellulose acetate, and the preferred crosslinking agent is Isonate
123P, a caprolactam blocked polymeric isocyanate available from the
Upjohn Company. In the design print layer or layers the preferred
crosslinkable material is a hydroxyl modified vinyl
chloride-vinylacetate resin and the preferred crosslinking agent is
butylated urea-formaldehyde polymeric material. In the adhesive
layer the preferred crosslinkable material is a carboxyl modified
vinylchloride-vinylacetate resin, and two epoxy crosslinking agents
are preferably used, namely, an epoxy modified
vinylchloride-vinylacetate copolymer resin and a diglycidyl
ether-bisphenol A type of polyepoxide. At curing temperatures
(200.degree.-450.degree.F), it is believed that the polyisocyanate
in the transfer lacquer layer becomes unblocked and reacts both
with the hydroxyl groups of the cellulose acetate in the transfer
lacquer layer and the hydroxyl groups of the hydroxyl modified
resin in the design print layer. It is similarly believed that the
butylated urea-formaldehyde in the design print layer reacts with
the same hydroxyl groups in the transfer lacquer and design print
layers, and also with both of the epoxides and also the carboxyl
groups in the adhesive layer. To complete the picture, the hydroxyl
groups of the hydroxyl modified resin in the design print layer
reacts with the now unblocked polyisocyanate in the transfer
lacquer layer, with the butylated ureaformaldehyde in its own
design print layer and with both of the epoxy compounds in the
adhesive layer. This system, involving various crosslinking agents
and crosslinkable materials gives a particularly strong, cohesive,
mar resistant, decorative label.
The invention will be further clarified with reference to the
following illustrative embodiments.
EXAMPLE 1
A heat transfer decoration was prepared by printing on a suitable
release surface as described in the above-mentioned U.S. Pat.
application, Ser. No. 244,292 by B. Asnes, a multiple layer print
applied by roto gravure, comprising a clear lacquer composed of
cellulose acetate, 9.8 parts, (E-398-3, made by Eastman Chemical
Products, Inc.) dissolved in 80 parts of methyl ethyl ketone and
8.9 parts acetone, and containing 0.4 parts of a fluorescent dye (a
substituted phenyl benzotriazole sold under the name Intrawite OB
by Intracolor Corporation) and 1.0 parts of blocked polymeric
isocyanate, (Isonate 123P, by Upjohn Co.). Inside the periphery of
the first printed dried clear lacquer there is printed the design
print using a reactive yellow ink consisting of 15.3 parts
butylated urea-formaldehyde resin solution (Resimene U-920, by
Monsanto), 11.5 parts hydroxyl modified vinylchloride-vinylacetate
copolymer resin (VAGD, by Union Carbide) dissolved in 12.5 parts
ethyl acetate, 34.2 parts n-propyl acetate, 16.6 parts toluol, and
3.2 parts isopropanol, and containing 0.1 parts silicone resin
(S-10, Union Carbide). Sumatra Yellow pigment by Hercules, 6.5
parts, is dispersed into this solution with a Cowles Dissolver and
the mixture is ground to No. 8 Hegman in a ball or sand mill. Over
the design print, but inside the periphery of the first clear
lacquer, a clear, curable, heat activatable adhesive layer is
printed, consisting of 13.9 parts epoxy modified
vinylchloride-vinylacetate copolymer resin (VERR, Union Carbide),
13.9 parts carboxyl modified vinylchloride-vinylacetate copolymer
resin (VMCA, Union Carbide) dissolved in 34.6 parts ethyl acetate
and 34.6 parts toluol, and containing 2.8 parts diglycidyl
ether-bisphenol A epoxy resin (ERL-2774, Union Carbide) and 0.2
parts ultraviolet absorber (Uvinul D-50, General Aniline and Film).
The applied heat-activatable adhesive over-print was dried to a
non-tacky but heat-activatable state. The final print is monitored
after the last press station under ultraviolet light which
fluoresced the dye in the clear transfer layer (first down lacquer)
to make it clearly visible, and was absorbed by the ultraviolet
absorber in the overprinted clear adhesive layer (last down
lacquer) so it appeared to be darker than the first down lacquer,
whereby it is possible to keep the two clear lacquers and the ink
print in perfect printing registration.
The resulting decorative label is transferred to a glass bottle in
the manner discussed above. Before decoration, an amino alkoxy
silane, i.e., a solution of gamma-aminopropyltriethoxysilane (0.05%
in Toluene-ethanol) (A-1100, Union Carbide) is applied to the
surface to be decorated. Application of the silane to the ware
imparts significant hydrolytic resistance to the cured decoration
on the ware. The container is then heated to
150.degree.-250.degree.F before the decoration is applied in a
Dennison TD1B heat transfer decorating machine at a speed of about
60 bottles per minute. Thereafter the decoration on the container
is cured in an oven for 10 to 20 minutes at 200.degree. to
300.degree.F and then further cured for 10 to 20 minutes in an oven
at 350.degree.F to 450.degree.F. After curing is complete, the
lacquer layer which surrounds the ink print, and protects it, is
observed to be water-white and nearly invisible.
The cured decoration will withstand 40 rubs with methyl ethyl
ketone with nothing removed, and a 30 minute immersion in boiling
water with very little removed by scotch tape after cross-hatching
with a razor.
EXAMPLE 2
A reactive white ink may be printed on top of the yellow ink in
Example 1 before application of the adhesive to provide opacity to
the transparent yellow color when the decoration is transferred to
the container. The reactive white ink consists of 10.1 parts
Resimene U-920, 7.7 parts VAGD, dissolved in 8.3 parts ethyl
acetate, 22.6 parts n-propyl acetate 11.0 parts toluol, 2.1 parts
isopropanol, and containing 0.05 parts S-10 silicone resin.
Titanium dioxide (OR-580, Cyanamid), 38 parts, is dispersed and
ground into the above formulation as in Example 1. Printing,
decorating and curing are the same as in Example 1.
EXAMPLE 3
A reactive transparent blue ink may be printed in addition to and
in line with the yellow ink in Example 1, over all of which a white
ink may be printed as in Example 2. The reactive blue ink consists
of 14.2 parts Resimene U-920, 10.8 parts VAGD, dissolved in 11.6
parts ethyl acetate, 31.9 parts n-propyl acetate, 15.5 parts
toluol, 3.0 parts isopropanol, and containing 0.1 parts S-10.
Monarch Blue pigment CFR X-3367 (Hercules), 12.9 parts is dispersed
and ground into the above formulation as in Example 1. Printing,
decorating, and curing are the same as in Example 1. The test
results are also similar to those in Example 1.
EXAMPLE 4
A reactive transparent red ink may be printed in addition to and in
line with the yellow ink in Example 1, the blue ink in Example 3,
over all of which a white ink may be printed as in Example 2. The
reactive red ink consists of 14.5 parts Resimene U-920, 10.9 parts
VAGD, dissolved in 11.9 parts ethyl acetate, 32.5 parts n-propyl
acetate, 15.8 parts toluol, 3.1 parts isopropanol, and containing
0.1 parts S-10. Sparta Red pigment (Hercules), 10.9 parts, is
dispersed and ground into the above formulation as in Example 1.
Printing, decorating, and curing are the same as in Example 1, with
similar test results.
While particular embodiments of the present invention have been
shown and described, it will be obvious to those skilled in the art
that changes and modifications may be made without departing from
this invention in its broader aspects. Therefore, it is intended
that the specification be interpreted as illustrative only, and not
in any limiting sense.
* * * * *