[0001] This application is a continuation-in-part of application no. 07/267,877 filed November
7, 1988, and is related to concurrently filed applications assigned International
Application Nos. PCT/US89/04887, PCT/US89/04886 and PCT/US89/04888, the disclosures
of said applications being incorporated by reference herein.
[0002] The present invention is directed to a label for labeling containers and a label
laminate for application of a label to a container.
[0003] Glass containers are currently labeled in three different ways. The predominant method
is printed paper labels glued to the container at the time of filling and sealing.
Such labels offer almost unlimited art potential and are commonly used on food, and
both returnable and non-returnable beverage containers. This is the lowest cost technique,
but offers little resistance to label damage from handling and exposure to moisture
or water, and may not survive the washing procedures required of a returnable container,
thereby requiring re-labeling.
[0004] A second, and more recently developed, container labeling technique is that of applying
a thin styrofoam label to cover the container from shoulder to heel, with the decorative
and/or informational material being printed on a more dense outer skin of the styrofoam
label. This is widely used on lighter-weight one-way bottles common in the beverage
industry. It offers some impact resistance and a large surface area for printing product
information and instructions, as well as company logos. It is, however, more costly
than the paper label, has little durability, becomes easily soiled, and will not survive
the alkali washing of a returnable beverage container, or the pasteurization required
by some beverage containers. Also, because the printing surface is relatively rough,
high definition printing is not possible.
[0005] A third container labeling technique is that of printing ceramic ink directly on
the container surface using a screen printing technology. While the label appearance
is generally good, the technique is typically limited to two or three colors due to
cost considerations. A recent development is the preprinting of a ceramic ink decal
which is then transferred to the glass container surface. This permits high definition
printing and offers greater opportunities for color and art variety. Fired ceramic
inks are extremely durable and will survive the alkali washing processes required
of a returnable container.
[0006] However, both the direct printing ceramic ink and ceramic ink decal techniques require
subsequent high temperature firing to fuse the ink to the glass substrate. In addition,
while the preprinted ceramic ink label reduces the technical problems somewhat, both
techniques require extreme attention to detail, a high level of maintenance and are
run off-line at slow speed, with high labor costs. Due to the high cost, ceramic inks
are the least commonly used labeling technique.
[0007] US-4292103 discloses a method of transfer printing. An adsorptive porous layer of
activated alumina or silica or a mixture thereof is formed on the surface of an object
to be colored or printed. A transfer material comprising a carrier sheet and a design
layer formed thereon and containing colorants forming a colored pattern is applied
to the absorptive porous layer. The carrier sheet is stripped away so that the design
layer is left adhered to the adsorptive porous layer. Heat is then applied to cause
the colorants in the design layer to migrate into the porous layer for exact reproduction
of the colored pattern thereon.
[0008] It is common practice in the glass container industry to treat the outer surface
of the containers with materials to counteract the effects of high glass-to-glass
friction experienced on freshly manufactured glass products. Glass containers are
conveyed with a great deal of glass-to-glass contact and at times considerable line
pressure. Without treatment there is considerable visible scratching which may result
in breakage. It is common to surface treat at two locations in the operation. Immediately
after forming and before lehring, the containers pass through a vapor which leaves
a tin oxide film bonded to the surface. After lehring the containers are sprayed with
a dilute water solution of a material which after evaporation of the water leaves
a film to provide surface lubricity. Of the two treatments the tin oxide film is most
costly, both for materials and system maintenance. The lubricity of the second film,
though needed to prevent surface damage, may cause problems in subsequent labeling
of the container.
[0009] There is an ongoing program in the container industry to reduce the weight of the
container by reducing wall thickness, but still maintain acceptable product strength
for both the internal pressures of carbonated beverages and the impact strength to
survive handling damage in the filling operations, in the market place and by the
consumer. The benefits of reduced weight are economic: lower glass melting fuel and
material costs, higher container manufacturing speeds (lower cost) and reduced product
shipping costs.
[0010] It is an aim of the present invention, with certain variations, to overcome the above-described
disadvantages of prior art labeling techniques and to offer solutions to the above-described
container industry problems.
[0011] It is a further aim of this invention to provide an efficient labeling-equipment
system for applying the improved label in line with the container manufacturing process,
e.g., at line speeds of 400 containers a minute and above.
[0012] The present invention provides a label laminate for application of a label to a container,
said label laminate comprising:
a backing layer;
a patterned layer on said backing layer, said patterned layer consisting of ink formed
in a pattern; and
a heat-activated adhesive overlying substantially only said patterned layer.
[0013] The present invention also provides a label for a container, comprising:
a label layer carrying information thereon and having first and second sides, with
said first side in use facing the container; and
a composite heat-activated adhesive of first and second layers, said first layer comprising
a bonding material adhered to said first side of said label layer and to said second
layer for bonding said second layer to said label layer, and said second layer comprising
a heat-activated adhesive material disposed on a side of said first layer which in
use faces the container for adhering said first layer, and thereby said label layer,
to said container.
[0014] These and other aims are achieved according to the present invention by applying
a label comprising a removable backing layer reverse printed with, e.g., a vinyl,
or acrylic ink which is cured and overprinted with adhesive, to the container with
its adhesive surface in contact with the container. The backing layer is separated
from the label, e.g., by the application of heat, while concurrently the ink bonds
to the container. The labeled container is then applied with a suitable coating, which
is then cured. The printing process provides the desired high definition printing
capability, and the coating provides the required degree of impact resistance and
durability.
[0015] It is a further aim of the invention to eliminate the cost of tin oxide coating.
Because the coating provides impact resistance and durability, it is no longer necessary
to provide the tin oxide film prior to container lehring. Instead, a token amount
of lubricating film is applied after annealing. This is preferably a film compatible
with the adhesion materials on the label inks and with the coating, although it could
alternatively be a film readily removed by oxidizing flame treatment prior to labeling.
This lubricating film is sufficient to enable damage-free conveying from the lehr,
through the inspection stations and into the labeling machine staging area.
[0016] Yet another aim of this invention is to foster continued further reduction in container
weight. It has been demonstrated that a container entirely coated with a nominal 15.24
microns (0.6 mil) of the coating will survive a 30-40% increase in fracture impact
over an uncoated container.
[0017] It is also well known that considerable glass surface damage occurs throughout the
container handling cycle including bulk and case packing at the container manufacturer.
At the container filling operations the handling surface damage is severe also. Because
the coating provides a much greater degree of surface protection, container failure
from surface damage would be greatly reduced. The applied layer of coating is complete
over the entire container surface including the label, without voids or discontinuities.
Further reductions in wall thickness without compromising container strength are therefore
possible. These reductions have value in increasing container manufacturing speeds,
reducing fuel usage and material costs as well as reducing transportation costs.
[0018] The invention will be more clearly understood from the following description in conjunction
with the accompanying drawings, wherein:
Fig. 1 illustrates all of the materials and their order of layering in a label for
application to a container in accordance with the present invention;
Figure 2 is a schematic diagram of a system for applying the label of Figure 1;
Figure 3 is a diagram of a novel web indexing mechanism which may be used in the system
of Figure 2;
Figure 4 is a diagram for explaining a suitable mechanism for applying the overcoat
layer in the system of Fig. 2; and
Figures 5A-5C illustrate various alternative label configurations.
[0019] The preferred embodiment of the application system according to the present invention
will be described first with reference to Fig. 1, which shows the glass container
1 and the label and substrate before application of the label to the container. The
label fabrication begins with a backing layer 10 of a suitable material, e.g., a polypropylene
film, which may be provided with an acrylic coating 12 to provide a high gloss surface.
The backing layer 10, either with or without the acrylic coating 12, is preferably
then coated on the side to be ink printed with a release material 14 activatable by
heat. The desired label is then printed on this coated backing layer 10 with a suitable
ink, preferably vinyl or acrylic ink 20. After application of the ink to the backing
material 10, the ink 20 is then cured, e.g., by heat or by electron beam or U-V energy.
After curing of the ink, a transparent bonding layer 30 is applied, preferably by
printing only over the ink pattern, and this is then covered with an adhesive layer
40 printed over the bonding layer 30. All of these operations are accomplished in
one pass through a multiple station gravure printer. The film-ink-adhesive laminate
is then rolled up and forwarded to the container labeling system.
[0020] The application of the label to a container will now be described with reference
to Fig. 2. For convenience, the description herein will be in the context of glass
bottles, although it should be recognized that the labelling technique is applicable
to all types of containers.
[0021] The bottles will be conveyed from the forming machine through an annealing lehr.
The application of tin oxide before lehring is not necessary, nor would it serve any
useful purpose with the new system. The bottles will then typically have been sprayed
with a lubricant, and according to this invention it must be a lubricant which is
compatible with the printed adhesives and coating, or which can be sufficiently removed
to permit the subsequent labelling. A suitable lubricant would be ammonium stearate
applied in a one-half percent (1/2%) water solution.
[0022] The bottles will then normally be subjected to a number of inspection criteria which
are well known in the industry.
[0023] In any event, the bottles are received along a conveyor 100 from an inspection area.
A typical system may provide bottles at a rate of 400 per minute, and it would be
preferable according to this invention to divide this into two streams of 200 per
minute each. For convenience, only one container stream is shown, it being understood
that the remaining one or more container streams would be processed in the same manner.
In each stream, as shown in Fig. 2, the bottles are passed one-at-a-time by a star
wheel control device 102 to a loading station 104. The bottles are then moved downwardly
in Fig. 2 onto an indexing table 106 by means of a suitable placement device. The
indexing table 106 will include container holders, e.g., suction holders or the like,
which are arranged in groups of three, with each group of three being arranged rectilinearly.
There may be supports at the neck of each container to absorb pressure during the
container transfer.
[0024] After loading three bottles onto the indexing table 106, the indexing table is then
rotated counterclockwise in Fig. 2 from the loading station to a container orienting
station generally designated at reference character 108. If desired or necessary for
the particular type of container and label being used, the container may here be rotated
to a particular orientation, although this will be unnecessary in many container labeling
systems. The rotating of the container would preferably be performed by rotation of
individual container holder suction cups on the indexing table 106 until the correct
position is detected, e.g., by suitable photo-electric means, at which point the holders
would be locked in their correct positions. (If locked, they will have to be unlocked
prior to the label application step, as the label application step requires rotation
of the bottles as will be described in more detail below.)
[0025] If it is desirable to burn off residual lubricant, this can be done at station 108,
in addition to proper orienting of the bottles, preferably by an oxidizing flame but
alternatively by other means such as corona treatment.
[0026] After processing at station 108, the indexing table 106 is further rotated to bring
the bottles to the label transfer station. At this point, the web 112, formed in the
manner described with reference to Fig. 1, is juxtaposed with the three bottles with
a respective label being adjacent each container. vinyl or acrylic ink labels are
then transferred to the bottles, in a manner which will be described in more detail
below, and the indexing table is then rotated to a coating station 114 where a suitable
protective coating is applied. A suitable coating material would be UV-curable or
heat-curable acrylic, one example of which is a UV-curable acrylic identified as R796Z80,
which is composed of film formers, resins, reactive diluents and additives and butyl
acetate solvents, manufactured by PPG Industries, Inc. and available from Brandt Manufacturing
Systems, Inc. However, any clear acrylic coating, as well as a number of other overcoat
materials, could be used without departing from the scope of the invention.
[0027] The indexing table 106 is then further rotated to bring the labeled and coated bottles
to an unloading station where each container is off-loaded onto a container conveyor.
There are a number of ways in which the bottles could be removed. All bottles could
be removed from the indexing table 106 to a single conveyor 120, taking care to ensure
that the acrylic coatings are not disturbed. It may, be necessary, with suitable care
taken, to use an air knife. It may, however, be necessary to move the bottles by clamping
them at their neck and carrying them onto the conveyor 120 in a known manner.
[0028] It is also to be remembered that the bottles are held in groups of three on the indexing
table 106. In the interest of speed, it would be possible to arrange three separate
conveyors 120 each for receiving one of the three bottles in each group from the indexing
table 106.
[0029] Once on the conveyor 120, the acrylic coating on the bottles is cured in a suitable
manner, e.g., by heat or U-V energy. For speed in the case of U-V curing, it would
be desirable to position U-V lamps on either side of each container. If desirable,
it would also be possible to rotate each container by 90° during the curing process
to provide full coverage of the container by the opposing lamps. After the curing
process, the conveyor 120 carries the bottles to a further container inspection area
(if desired) and thence to a packing or filling station.
[0030] The handling of the label during application of that label to the container in the
system of Fig. 2 will now be discussed in more detail. As will be recalled from the
discussion earlier herein, the label has been fabricated in the form of a film-ink-adhesive
laminate which has been rolled up. The web will preferably have a leader and a tail
area for continuous feed through the application equipment when the leader and tail
pieces of successive laminates are connected.
[0031] The laminate is held on a supply reel 116. The adhesive has been permitted to cure
to a point at which it is no longer tacky, thus permitting the label to be rolled
up and subsequently unrolled. Prior to application of the label to the container,
the adhesive may have to be activated, and this may be done by applying heat to the
web 112 at some point prior to the warm platen 130, e.g., at the location designated
by reference character 132. The heat could be applied by way of infra-red lamp array
and would have to be sufficient to permit the adhesive to melt, e.g., on the order
of 82.22°C (180°F). A preferred adhesive would be that disclosed in International
Publication WO-A-90/05353 (International Application No. PCT/US89/04888) identified
above. At bottle rates of on the order of 200 per minute, the heating of the bottles
prior to the labelling station is sufficient that the adhesive is activated immediately
upon contact with the bottle, and no preheating of the adhesive is necessary. At higher
rates, e.g., 500 per minute, it may be that additional preheating of the adhesive
will be needed.
[0032] Alternatively, the adhesive used may be of a type which does not require activation.
In this case, it would merely be necessary to coat the substrate 10, on the surface
thereof opposite the surface carrying the ink, with a suitable coating material to
prevent adherence of the adhesive to the layer 10 when the label is rolled up onto
the supply reel 116. Such coatings are well known in the art and need not be described
in detail herein.
[0033] A still further option would be to omit the adhesive entirely in the process of fabrication
of the label, and to apply the adhesive for the first time to the web 112 at the location
132, or to apply it to the container itself just prior to the labelling station.
[0034] Regardless of what type of adhesive is used and how it is activated, if at all, the
labeling web will be passed across a warm platen 130 prior to the label transfer station.
The purpose of this warm platen is to ensure that the temperature of the label laminate,
and especially the release agent 14, is such as to permit easy separation of the backing
layer 10 from the ink label. This typically requires a release temperature of approximately
93.33°C (200°F) with a few degrees tolerance on either side. A heated roll 134 is
then used to press the label onto each container, and the backing layer 10 is then
removed by a take-up reel 150.
[0035] The manner of handling the labeling web will be further described with reference
to Fig. 3. As will be recalled, the indexing table 106 holds the bottles in groups
of three, and it is desirable to handle the labeling web in such a manner as to permit
application of labels to three bottles substantially simultaneously. It will also
be recalled that, for a rate of approximately 200 bottles per minute for each indexing
table, and with the bottles being handled in groups of three, the table is indexed
a little less than once per second. Accounting for table travel time, this allows
approximately 1/2 second for each label transfer. The present inventors have devised
a novel and effective mechanism whereby, during this 1/2 second interval, the labelling
web 112 in Fig. 2 is advanced past the bottles by an amount corresponding to two successive
labels to make ready for labeling the next three bottles.
[0036] The label supply reel 116 and/or first capstan 142 are provided with brake mechanisms.
Beginning with three unlabeled bottles at the label transfer station, it will first
be noted that the bottles are preferably held in position such that their centers
are separated from one another by a distance at equal to the linear distance between
leading edges of successive labels. The label web is then advanced to a position such
that the beginning of each of three different labels will be in contact with the circumference
of a respective container. The web is then pulled past the bottles, with the bottles
being rotated by the adhesion with the web. The preferred embodiment illustrated in
Fig. 2 includes a separate heated roll 134 for each of the three containers in a group.
In addition, the rolls may preferably be implemented in the form of inflated bladders
to permit accommodation of minor surface irregularities.
[0037] During movement of the web past the bottles between label applications, the web and
bottles must be out of contact with one another, while they must obviously be in contact
during the application of the label. This will require either that the web be moved
toward and away from the indexing table or that the bottles be movable radially with
respect to the indexing table. The latter would be preferred.
[0038] With reference to Fig. 3, the slow movement of the web past the bottles is accomplished,
with the brakes on the supply reel 116 and capstan 142 in Fig. 2 disengaged, by moving
the roller 144 in the rightward direction in Fig. 3 while a brake associated with
capstan 146 or take-up reel 150 is engaged. The roller 144 is permitted to rotate
freely during this rightward movement. As will be easily understood, movement of the
web 112 through a distance L will be accomplished by moving the roller 144 through
a distance L/2. Thus, the roller 144 is moved by a distance L equal to one-half the
length of a label so that the labels may be completely applied, and then the roller
144 must continue its movement by an amount sufficient to move the used web beyond
the labelling station until the leading edge of the next unused label is at the proper
position for application to the container closest to the roller 144. After this movement
of the roller 144 has been completed, the brake on the supply reel 116 or capstan
142 is applied while that on capstan 146 or take-up reel 150 is released. The roller
144 is quickly moved back to its leftward position in Fig. 3 while the take-up reel
150 takes up the slack.
[0039] The movement of the roller 144 to move out the used label web and the subsequent
movement of the roller 144 back to the left in Fig. 3 may preferably be performed
during rotation of the indexing table.
[0040] Fig. 4 provides a brief diagram for explaining one technique for applying the protective
coating at station 114 in Fig. 2. A drum 160 having apertures in its periphery would
provide the acrylic (e.g., urethane) coating solution to a sponge belt 162. A backing
roller 164, or leading and trailing rollers if desired, would then press the sponge
belt 162 against the periphery of the labelled container 166. The thickness of the
applied coating could be controlled by controlling the rate at which the coating material
is supplied by the drum 160 depending on bottle shape and area to be coated additional
belt arrangements may be necessary and the flexible belt 162 will conform to the curve
in the shoulder of the container. In addition, it would be possible to confine the
application of coating solution to a specific region in the width direction of the
belt 162, either by designing the length of the drum of by controlling the opening
and closing of certain apertures at different axial positions of the drum. This would
allow the application of a protective coating to certain portions of the container,
or would indeed permit the thickness of the coating to vary over the length of the
container, e.g., a 25.4 micron (1 mil) thickness over most of the container and only
a 12.7 micron (0.5 mil) thickness over the label.
[0041] Depending on bottle shape and area to be coated, additional belt arrangements may
be necessary.
[0042] While it is expected that the adhesion between the belt 162 and bottle 166 will be
sufficient to rotate the bottle during the coating process, it may nevertheless be
desirable to actively rotate the bottle, e.g., by means of its holder on the indexing
table.
[0043] A benefit of the coating material is that it adds to the strength of the container,
and may therefore permit fabrication of thinner bottles while still meeting industry
standards for strength and durability. The durability could be further enhanced by
adding microspheres to the coating material, such as those available from Potter's
Industries.
[0044] An additional benefit of the coating layer is that it will tend to fill in any scratches
or other similar surface defects in the container, thereby substantially improving
the appearance of the container.
[0045] It may be that prior to the processing shown in Fig. 2 the bottles will already have
been provided with a protective coating, either clear or colored, as described in
International Publications WO-A-90/05031 and WO-A-90/05667 (International Applications
PCT/US89/04887 and PCT/US89/04886). In view of the earlier application of the protective
layer which would enhance the strength of the container, the clear protective layer
applied at the station 114 could be thinner, since its only purpose would be label
protection.
[0046] If not already provided with a colored overcoat prior to labelling, it may be desirable
to add color to the coating applied at station 114 in Fig. 2. This would allow for
some further coloring of the labels but would also permit the simulation of different
color bottles. This would allow a container manufacturer to provide a range of colored
containers on demand, while avoiding the costly down time associated with changing
over from one color to another in the melting unit and the cost of raw materials and
batching equipment over the basic cost of clear glass.
[0047] A further significant advantage would be that, in recycling of the bottles, it would
no longer be necessary to segregate the bottles by color. The glass would all be clear
flint glass and the coating would be burned off prior to or at the time of melting
down of the returned bottles.
[0048] A further improvement would be the inclusion in the protective overcoat layer of
a light blocking agent to hinder or prevent changes in the taste or appearance of
the container contents, e.g., beer. The light blocking agent would block a suitable
wavelength of light, e.g., U-V light at approximately 400 nanometers, and would be
substantially clear so that it would not have a significant effect on the color of
the clear coating, and would be entirely compatible with a colored coating. It would
be necessary, of course, that the U-V blocking agent added to the coating material
not interfere with whatever curing process was used for the coating, even if that
curing process were U-V curing.
[0049] While the above description has indicated the use of vinyl or acrylic ink for printing
the labels, it may be that other inks would suffice as long as they do not bleed into
the overcoat material.
[0050] While the preferred embodiment of the invention has been described above, there are
many alternatives which may be employed, some of which will be described hereunder.
[0051] A first option (Fig. 5A) is a single-film label which may be gravure printed on a
polypropylene or suitable paper web 200 for subsequent heat release. If desired, as
was the case in the preferred embodiment described above, a protective coating may
be applied to the container after labelling, and this coating may be cured, by U-V,
E-B or other energy, if desired. In Fig. 5A, this is illustrated as layer 202 which
would be applied to the web 200 first, so that it will be on the exterior of the package
after label application. A suitable material for the film material 202 is acrylic.
and the label ink 204 is vinyl or acrylic. An adhesive 206 (e.g., comprising both
of the layers 30 and 40 in Fig. 1) is applied in stripes to provide escape passages
for air and moisture. The adhesive could be either (1) applied to the film at the
time of printing of the single film on the web, cured and reactivated prior to application
of the film to the container, or (2) applied to the printed web immediately before
application of the film to the container. (It could, of course, alternatively be applied
to the container.)
[0052] A second option (Fig. 5B) would be a two-layer label wherein the first layer would
comprise the components 200 and 204, and optionally the protective antiabrade layer
202, as in the first option of Fig. 5A. The second layer would be a cushion layer
208 of organic material. The cushion layer could be applied (1) to the web-film laminate
at the time of printing or immediately prior to application of the first film to the
container, or (2) to the container itself immediately prior to application of the
film to the container. The cushion layer would preferably be organic, and would be
designed to release CO
2 micro-bubbles when energized with heat, U-V or E-B energy, either at the time of
laminating or immediately prior to application to the container. Alternatively, the
cushion layer may contain glass or plastic microspheres.
[0053] A third option (Fig. 5C) would be the same as the second option but the cushion layer
would be a clear layer 210 applied during a single pass or multi-pass during the label
printing. It would then be cured during the printing operation with U-V, E-B or other
energy.
[0054] A sixth option (not shown) would be to apply a clear cushion coating after application
of the label of Fig. 5A.
[0055] In each of Figs. 5A-5C, there could also be a release agent on the surface of the
polypropylene web 200 on the side of the bottle, i.e., between the web 200 and the
remainder of the laminate, to facilitate removal of the web 200 while the label is
still hot. It may in some cases be preferable not to use a release agent, in which
case the web may be peeled off after cooling of the label.
[0056] A further feature of the invention is that the web, e.g., 10 in Fig. 1, may be reused
after separation from the label. The used web may be taken from the take-up reel and
re-laminated with whatever layer configuration is being used for labelling. This would
represent a considerable cost savings. It would be necessary to modify present label
printing machines to run several webs side-by-side, as opposed to the present practice
of simultaneously printing plural labels on a web which is multiple labels wide and
then slitting the wide web into single label-wide webs, but this may be justified
by the cost savings.
[0057] It can be seen that a great number of significant advantages result from the invention
as described above. The present invention provides a low-cost labelling system which
can be easily modified to meet various product requirements. This method allows the
label to be applied in-line with the container manufacture. The systems will operate
at speeds in excess of 400 containers per minute, and can handle containers of varying
size and shape with simple modular changeover. They are also advantageous in that
they are designed for use between the container inspection stations and final pack.
[0058] The web markings allow for accurate registry of the labels during printing and application,
and the re-use of the web may result in significant cost savings. Also, the printing
of the labels on a continuous web wound on reels facilitates transportation and machine
loading, and the ability to connect the webs end- to-end will permit continuous labelling
without interruption.
[0059] Indeed, the labelling system of this invention can be operated on demand, with nominal
heat up time of the U-V or E-B cure system.
[0060] In addition to the various process advantages described above, the end product is
also improved. The label is of high visual quality and is also durable, and the coated
container has a high degree of impact resistance. This is especially true if microbubbles,
microspheres, etc., are used to such an extent as to form an energy-absorbing network
for dissipating impacts, but it is also to be noted that a high degree of impact resistance
is obtained even when the outer layer is clear and the underlying label highly visible.
[0061] The label with overcoat will be able to withstand the water wash and pasteurization
processes associated with non-returnable containers, and with chemical modifications
to the overcoat, returnable containers will be able to survive the alkali wash required
prior to refilling. Nor will the label or overcoat be adversely affected by water,
alcohol or organic materials used in the filling operations.
[0062] The labels on adjacent containers will not abrade each other during the filling and
packaging operations associated with transport, store display and consumer purchasing,
and the labels will also be chemically and physically stable.
[0063] The coating materials can be cured in-line by U-V, E-B in a few seconds in a very
energy efficient manner.
[0064] The overcoating of a labelled glass container provides increased impact and abrasion
resistance, while maintaining high gloss and visual enhancement of the label and coated
portion. The overcoating of a labelled glass container in accordance with the present
invention also provides for surface improvement both structurally and in appearance
by filling surface flaws or microfissures with the overcoat material so as to make
the flaws invisible. Such flaws may be from the glass mold itself.
[0065] Finally, the present invention provides a method of reverse printing a film, paper
or other printing web of multiple inking, eliminating a costly label process at the
container filling plant and at the same time giving the glass container industry a
value added product. In addition, the use of a coupling agent to promote adhesion
of the overcoat material to the container surface may be necessary to meet certain
container processing and use requirements, specifically, but not limited to the typical
beer industry pasteurization process. A suitable coupling agent is "A-1120" available
from Union-Carbide Corporation.
[0066] The application of the coating may be accomplished by belt or roller coating described
elsewhere, or by spraying the material. In the event the materials are sprayed it
is necessary to prevent any material from contacting the finish of the container.
This is the area including the opening, top seal surface, thread or closure cover
area and protuberance immediately below. This can be accomplished, for example, by
using a container gripper device designed to completely cover the area described above,
e.g., designed with a split housing which when closed will dovetail to form a barrier
to the spray material.
[0067] The gripper devices may be attached to a conveyor network whose design allows for
variable spacing of the glass containers to optimize the coating, drying, and U-V
curing of the various materials. The design may also provide for rotating the gripper
and container at the spraying and U-V curing positions to insure uniform coating and
processing.
[0068] Another feature of the Invention is the use of electro-statics to compliment the
protective gripper and operate in conjunction with it and described elsewhere.
[0069] It will be appreciated that further modifications could be made to the embodimemt
disclosed above while still obtaining many of these advantages and without departing
from the scope of the invention as defined in the appended claims. For example, the
heat release material 14 in Fig. 1 may be dispensed with and instead the ink printed
directly on the acrylic layer 12, as is the case with the illustrations of Figs. 5A-5C.
When the label has cooled, the adhesion between the container and ink will be greater
than that between the ink and acrylic layer 12, and the substrate and acrylic layer
can simply be peeled off. If the heat release layer 14 of Fig. 1 is to be used, or
added to the labels of Figs. 5A-5C, it should be a material which either will not
transfer to the container with the ink, or will be compatible with any subsequent
overcoat if it does transfer, e.g., an acrylic material. It should also be a material
which can be printed.
[0070] A preferred embodiment of the present invention also provides a system for applying
labels in an efficient manner so that it can be performed on-line. The efficiency
is in part due to a novel label web indexing machine including a movable shuttle roller
and alternating braking mechanisms at the supply and take-up ends. This is especially
advantageous when simultaneously applying labels to a plurality of containers. The
collection of the used web on a take-up reel permits re-use of the web for further
cost savings. It is also possible to modify existing commercial container labeling
systems to accomplish the label application, in which case the heat necessary for
ink release and adhesive activation can be provided by heating the container to a
temperature of 93.33°C (200°F) prior to entering the labeling machine.