Variable double sided linerless labels

An advantageous linerless label assembly is produced by substantially full face coating a first substrate web second face with a first pressure sensitive adhesive, and substantially full face coating a second substrate web first face with a second pressure sensitive adhesive that is physically or chemically incompatible with the first adhesive, and then bringing the first and second adhesives into direct contact with each other. The substrates are formed into discrete separable labels which may be in sheet, roll, or fan-fold configuration. The individual labels in the substrate can either have the leading edges of each aligned with each other, or the leading edges can be spaced from each other (e.g. about half the length of each of the labels). When physically incompatible adhesives are used, the first adhesive may be vegetable based, polyvinyl alcohol or ultraviolet reactivated adhesive, and the second acrylic. When chemically incompatible adhesives are utilized, the first may be an acrylate adhesive and the second a copolymer of that acrylate adhesive and acrylonitrile.

BACKGROUND AND SUMMARY OF THE INVENTION 
Linerless label products are becoming increasing more popular because of 
environmental and other advantages associated therewith because they 
eliminate the need for a release sheet. Typically linerless labels are 
manufactured in a roll configuration where an adhesive is applied to one 
side of a continuous web and a release coating applied to the other, such 
as in U.S. Pat. Nos. 5,292,713 and 5,324,078. 
Sometimes linered labels are supplied in a configuration where there is 
essentially a double thickness of the linered labels, linered labels being 
provided on opposite sides of a release sheet, such as shown in U.S. Pat. 
No. 5,143,466. The same general type of configuration has been provided 
for linerless labels, such shown in U.S. Pat. Nos. 5,336,541 and 
3,312,005, however in those situations alternating strips of adhesive and 
release coating are necessary requiring use of release material and 
resulting in only approximately 50% adhesive coverage on each of the 
individual labels. 
According to the present invention a linerless label assembly, and method 
of manufacturing linerless labels, are provided which have all of the 
advantages associated with the linerless labels of U.S. Pat. No. 5,336,541 
(being linerless, not requiring a release coating on the face opposite the 
substrate, and providing a double thickness of labels) while having the 
additional advantages of not requiring any release coating at all, and 
substantially full coverage of adhesive on each of the labels. The term 
"substantially full coverage" as used in the present specification and 
claims means that alternating strips and release coatings are not required 
and typically at least about 80% adhesive coverage is provided (except for 
very speciality uses such as where a nonadhesive tab on the label is 
designed to be detached from the label). The label assembly according to 
the present invention requires no release coatings of any kind but rather 
face-to-face labels are separated from engagement with each other merely 
because of incompatibilities between the adhesives on the labels that are 
in contact with each other. 
The labels produced according to the present invention thus may be less 
expensive to produce than other linerless labels performing the same basic 
function (such as in U.S. Pat. No. 5,336,541) while providing better 
adhesive holding properties when applied to a package or product with 
which the label is designed to be ultimately used, while eliminating the 
expense and environmental problems associated with release (e.g. silicone) 
liners. The labels according to the present invention are compatible with 
conventional intelligent imaging equipment and, therefore, may be readily 
printed or otherwise imaged. Since there is no release coat on the face 
thereof to be imaged, each of the labels may be readily printed or 
otherwise imaged with a wide variety of different equipment and at almost 
any point in the manufacturing--application procedure. Also, the 
assemblies according to the present invention may be in a wide variety of 
configurations including roll form (continuous), sheets, or fanfold. 
According to one aspect of the invention a linerless label assembly is 
provided comprising the following: A first linerless label comprising a 
substrate (e.g. paper) having first and second faces, and a substantially 
full coverage first adhesive on the second face thereof. A second 
linerless label comprising a substrate (e.g. paper) having first and 
second faces, and a substantially full coverage second adhesive on the 
first face thereof. The first and second adhesives being physically or 
chemically incompatible with each other so that they can be separated from 
each other without significant damage to the substrates or the adhesives, 
the first adhesive having a much higher affinity for the first substrate 
than for the second adhesive, and the second adhesive having a much higher 
affinity for the second substrate than for the first adhesive. And the 
first label second face in separable face-to-face engagement with at least 
about 50% of the second label first face so that the first and second 
adhesives are in direct engagement with each other. 
The first and second adhesives both comprise pressure sensitive adhesive. 
The first substrate first face and second substrate second face are 
typically uncoated (they need not be coated for adhesive release 
properties, but may be coated to provide longer life in use, or for other 
purposes) and having indicia thereon. The indicia may be applied at any 
time during the process of producing labels. The first and second 
adhesives may be chemically incompatible. Examples of chemically 
incompatible adhesives are a first adhesive of isooctylacrylate and a 
second adhesive of a copolymer of isooctylacrylate and acrylonitrile, and 
a first adhesive of isodecylacrylate and a second adhesive of a copolymer 
of isodecylacrylate and acrylonitrile, and a first adhesive of 
ethylhexylacrylate and a second adhesive of a copolymer of 
ethylhexylacrylate and acrylonitrile, although there are a variety of 
other known and to be developed chemically incompatible adhesives that may 
be effectively utilized. 
Where the first and second adhesives are physically incompatible, the 
second adhesive may be acrylic, and the first adhesive may be a vegetable 
based, polyvinyl alcohol, rubber based, protein based, or ultraviolet 
reactivated adhesive. Other existing or to be developed physically 
incompatible adhesives may also be utilized. 
According to another aspect of the present invention a linerless label 
assembly is provided comprising the following: A first web or sheet 
comprising a plurality of individual linerless labels each having first 
and second faces and a substantially full coverage first pressure 
sensitive adhesive on the second face. A second web or sheet comprising a 
plurality of individual linerless labels having first and second faces and 
a substantially full coverage second pressure sensitive adhesive on the 
first face. And the first and second adhesives being physically or 
chemically incompatible with each other, and in direct engagement with 
each other so that the first and second webs or sheets are releasably 
connected to each other. 
A wide variety of configurations of the label assembly may be provided. 
Typically each of the individual linerless labels has a leading edge, and 
the first web or sheet label leading edges may be in alignment with the 
second web or sheet individual linerless labels leading edges; or the 
leading edges of the respective webs or sheets may be spaced from each 
other (e.g. about one-half the length of the majority of the labels of 
each of the web or sheet). The first and second adhesives may specifically 
be as described above. The assembly may be in roll, sheet, or fanfold 
configuration. 
According to another aspect of the present invention a method of 
manufacturing a linerless label assembly utilizing a first substrate web 
(e.g. paper) having first and second faces, and a second substrate web 
(e.g. paper or synthetic sheet) having first and second faces, is 
provided. The method comprises the following steps: (a) Substantially full 
face coating the first substrate web second face with a first adhesive. 
(b) Substantially full face coating the second substrate web first face 
with a second adhesive that is physically or chemically incompatible with 
the first adhesive. (c) Bringing the first adhesive on the first substrate 
second face into direct contact with the second adhesive on the second 
substrate first face. And (d) forming the substrates into discrete 
separable labels. 
Steps (a) and (b) are typically practiced by coating both the substrate 
faces with pressure sensitive adhesives, such as the physically or 
chemically incompatible adhesives described above. There may be the 
further step of forming the substrates of discrete labels into a 
configuration of a roll, individual sheets with a plurality of labels from 
each substrate in each sheet, or a fanfold configuration. Step (d) may be 
practiced before or after step (c), or parts of step (d) practiced both 
before and after step (c). Imaging may be practiced at any time during 
manufacture, or at any time before (or after) application of the final 
labels to the surfaces on which they are to be ultimately applied. Because 
the first substrate web and the second substrate web second face may be 
devoid of adhesive release coat material, effective and versatile imaging 
is simple and easy to accomplish.

DETAILED DESCRIPTION OF THE DRAWINGS 
FIG. 1 shows a linerless label assembly 10 according to the present 
invention in its simplest form, merely comprising two linerless labels in 
face-to-face engagement, FIG. 1 illustrating the labels as they are being 
pulled apart. The first label 11 comprises a substrate (such as paper, 
although any other suitable label substrate material may be utilized) 
having a first face 12 and a second face 13. The second face 13 has a 
substantially full coverage first pressure sensitive adhesive 14 thereon. 
By substantially full coverage it is meant that the adhesive 14 is 
substantially continuous, rather than being applied in strips, and 
typically covers at least about 80% of the face 13 (except for speciality 
applications such as where a nonadhesive tab is designed to be separated 
from the label 11). While the first adhesive 14 typically covers at least 
90% of the face 13 and may cover 100%, it need not cover 100% and in some 
circumstances it is desirable that it not cover 100% of the face 13. In 
the embodiment illustrated in FIG. 1 there is corner 15 and a side strip 
16 of face 13 that are both uncovered by the first pressure sensitive 
adhesive 14. 
FIG. 1 also shows the second linerless label 17 having a first face 18 and 
a second face 19 (only the edge of which is visible in FIG. 1). On the 
first face 18 is a substantially full coverage second pressure sensitive 
adhesive 20. In the embodiment illustrated the second adhesive 20 covers 
more than 90% of the face 18, but a corner 21--in alignment with the 
corner 15--is left uncovered. 
The labels 11, 17 each have a leading edge, 22, 23 respectively. In those 
circumstances where leading edges 22, 23 are in alignment with each other 
(as in FIG. 1), it may be desirable to provide the adhesive-free corners 
15, 21 to facilitate separation between the labels 11, 17 since even 
though the adhesives 14, 20 are incompatible (as will be hereafter more 
fully explained) they have a certain tackiness which tends to hold them 
together. 
The adhesives 14, 20 are incompatible with each other. The adhesive 14 has 
a much higher affinity for the face 13 (or to a tie coat on the face 13 
for facilitating adherence of the adhesive 14 thereto) than it does for 
the second adhesive 20, while the second adhesive 20 has a much higher 
affinity for the face 18 (or a tie coat thereon) than it does for the 
first adhesive 14. Even though the adhesives 14, 20 are incompatible, 
since they are pressure sensitive adhesive they have a certain tack, and 
will normally be held in face-to-face engagement until a force is applied 
thereto to separate them. However, when they separate they separate 
cleanly, without any destruction of the substrates of the labels 11, 17, 
and without any significant amount of adhesive from one label separating 
with the other. 
While a wide variety of incompatible properties may be employed for the 
adhesives 14, 20 of the label assembly 10, preferably the adhesives 14, 20 
are either physically or chemically incompatible. While a wide variety of 
different physically incompatible adhesives, now existing or to be 
developed, may be employed, some specific examples are acrylic adhesive as 
the second adhesive 20, and vegetable based adhesive, or a polyvinyl 
alcohol adhesive, or a rubber based adhesive, or a protein based adhesive, 
or an ultraviolet reactivated adhesive (that is adhesive that becomes 
tacky when exposed to ultraviolet light) as the first adhesive 14 (or vice 
versa). 
While a wide variety of chemically incompatible adhesives may also be 
utilized (presently existing or to be developed), some suitable examples 
are isooctylacrylate as the first adhesive 14 and a copolymer of 
isooctylacrylate and acrylonitrile as the second adhesive 20; 
isodecylacrylate as the first adhesive 14 and a copolymer of 
isodecylacrylate and acrylonitrile as the second adhesive 20; and 
ethylhexylacrylate as the first adhesive 14 and a copolymer of 
ethylhexylacrylate and acrylonitrile as the second adhesive 20. That is in 
general an acrylate adhesive and a copolymer of that adhesive, and 
acrylonitrile may comprise the incompatible adhesives. 
The first face 12 of the first label substrate 11, and the second face 19 
of the second label substrate 17 typically will have indicia applied 
thereon at some point during the manufacturing process, or certainly 
before actual application to a surface (e.g. package, container, or the 
like) to which the label 11, 17 is ultimately applied. FIG. 1 
schematically illustrates indicia 24 which has been printed or otherwise 
imaged on the face 12, it being understood that such indicia 24 also is at 
some point provided on the face 19 too. 
Utilizing the basic label assembly 10 according to the present invention, 
almost any configuration can be provided. For example, as illustrated in 
FIG. 2 a roll configuration 25 is provided. In the roll configuration 25 
illustrated in FIG. 2 note that the leading edges 22, 23 of the labels 11, 
17 are spaced from each other. In this embodiment the labels 11, 17 have 
the same length as each other, and the leading edges 22, 23 are typically 
at about the midpoint of the length of the opposite label 17, 11. However, 
the labels 11, 17 could have different lengths with the leading edges 22, 
23 then inherently and appropriately scattered, or the leading edges 22, 
23 may be aligned (especially where there is not 100% coverage of the 
faces 13, 18 by the adhesives 14, 20, respectively, but rather elements 
such as the nonadhesive corners 15, 21 are provided). Also, each of the 
labels 11 may be separated from other labels 11 (that is, at the leading 
edges 22 thereof) by perforations or other lines of weakness, rather than 
clean die cuts such as illustrated at 22 in FIG. 1. Of course, the leading 
edges 23 also may be perforations or lines of weakness rather than die 
cuts too. 
FIG. 3 illustrates label assemblies according to the present invention in 
sheet form in an exploded stack. In the configuration 27 the leading edges 
22, 23 of the labels 11, 17 are aligned with each other. In this 
configuration the leading edges 22, 23 typically would be lines of 
weakness rather than die cuts, although instead the labels 11 may be tied 
together along one or both side edges thereof by tie strips having line of 
weakness interfaces with the labels 11, and/or by similar tie strips for 
the labels 17. 
The sheet 29 in FIG. 3 has the leading edges 22, 23 of the labels 11, 17 
offset from each other. Depending upon the lengths of the labels 11, 17 
the end edges of the label assembly of the sheet 29 may be in alignment 
with each other, or instead--as illustrated in association with the labels 
11 in FIG. 3--smaller size labels 30 are provided at the ends of the 
labels 11. The smaller size labels 30 may actually be used as labels, or 
may be discarded. 
The label assembly 31 of FIGURE shows a sheet in which the labels 11, 17 
are the same length, with small labels 30 being provided in association 
with the labels 11 at one end of the assembly/sheet 31, while smaller 
labels 32 are provided in association with the labels 17 at the opposite 
end of the assembly/sheet 31. 
FIG. 4 schematically illustrates a fanfold configuration 34 of labels 11, 
17 of an assembly according to the present invention. In FIG. 4 the labels 
11, 17 are shown as offset from each other (the leading edges 22, 23 
spaced from each other) typically with the fanfolding being provided at 
one of the leading edges 22, 23. However, other configurations are also 
possible. FIG. 5 schematically illustrates exemplary apparatus 38 that may 
be utilized in the manufacture of linerless label assemblies according to 
the present invention. Reference numeral 39 illustrates a roll of a 
substrate material web 40, typically paper, having a first face 41 and a 
second face 42. The face 42 is coated with a pressure sensitive first 
adhesive (e.g. 14) as indicated by coating station 43. The coating station 
43 may comprise a full face coater, applying adhesive to the entire face 
42, or the coater 43 may comprise a spot coater which does not apply 
adhesive at certain points merely to facilitate slitting of the web 40 
along the width thereof into individual label assembly lengths, or to 
provide portions such as illustrated at 15, 21 in FIG. 1, etc. At least 
about 80% of the surface 42 is typically coated with the first adhesive by 
the coater 43. After coating at 43 (or even before coating at 43) the web 
40 may be perfed or cut (as long as integral portions of the web 40 are 
still provided) into the basic form of individual labels, utilizing 
conventional equipment. 
A source of substrate is illustrated at 45 in FIG. 5, the web 46 also 
typically being paper or other conventional label substrate, and having 
first and second faces 47, 48, respectively. The first face 47 is 
typically coated with a second pressure sensitive adhesive (e.g. 20) by 
the conventional coating equipment 49 which may be the same as the 
equipment 43. Conventional cut or perfing is also provided as indicated at 
50 either before or after the coater 49. 
The webs 40, 46 need not be coated on the faces 41, 48 thereof with any 
material. There is no necessity of coating faces 41, 48 with adhesive 
release material, and if they are coated with any other material it is for 
purposes other than adhesive release (such as for protecting the label 
during use or the like). 
After passing coating stations 43, 49 (and once the adhesives 14, 20 have 
dried) the webs 40, 46 are merged--as illustrated schematically at 52 in 
FIG. 5--utilizing conventional equipment so that the adhesive coated faces 
42, 47 come into face-to-face direct engagement with each other (i.e. the 
adhesives 14, 20 are in direct contact with each other). Downstream of the 
merging 52 cut or petting action for forming individual labels may be 
practiced. For example, if the equipment 44, 50 only partially forms the 
webs 40, 46 into individual labels (for example by cross cutting, or cross 
perfing), then conventional slitting equipment--as illustrated 
schematically at 53--in FIG. 5 may be utilized to form the final labels, 
e.g. by slitting off side edges from the webs 40, 46 (and also perhaps by 
slitting the webs 40, 46 into distinct strips of labels so that a 
plurality are provided along the width of the webs 40, 46). Alternatively 
to equipment 44, 50, 53 conventional cut or perf equipment 54 may be 
provided downstream of the merge equipment 52 for forming the webs 40, 46 
into individual labels at that time. That is, the formation of the webs 
40, 46 into individual labels may take place prior to merging at 52, after 
merging at 52, or parts both before and after merging at 52. 
The web 40, 46 faces 41, 48 may be imaged at any time during production 
(and indeed the faces 42, 47 may also be imaged prior to the adhesive 
application where the adhesive is designed to be applied to a transparent 
surface or the like). Because the faces 41, 48 typically are not coated 
with adhesive release material, or any other material, they may be imaged 
utilizing virtually any type of conventional printing or other type of 
imaging equipment and at high speed. Exemplary types of conventional 
printers that may be used for both individual sheet or continuous products 
are Dot Matrix, Direct Thermal, Thermal Transfer, Laser Ink Jet and 
Digital Color. For example, imaging may take place as illustrated 
schematically at 55 in FIG. 5, the faces 41, 48 being imaged substantially 
simultaneously. The equipment 55 typically applies indicia such as 
schematically illustrate at 24 in FIG. 1. 
Ultimately, the label assemblies according to the present invention, 
produced utilizing the equipment 38, are taken up as illustrated 
schematically at 56 in FIG. 5. The takeup 56 may be a conventional rolling 
station in order to form rolls such as illustrated at 25 in FIG. 2, or may 
be conventional sheeting equipment (for example, bursting or cutting the 
webs 40/46 into sheets such as 27, 29, 31 as seen in FIG. 3), or 
conventional fanfolding equipment (e.g. to produce a configuration 34 
illustrated in FIG. 4). 
It will thus be seen that according to the present invention an 
advantageous linerless label assembly, and method of manufacturing a 
linerless label assembly, have been provided. The label assembly according 
to the present invention is simpler and less expensive to make than many 
conventional linerless labels, yet has the environmental friendliness 
associated therewith. Also, it has substantially full adhesive coverage of 
each of the labels, which is advantageous in numerous circumstances. 
While the invention has been herein shown and described in what is 
presently conceived to be the most practical and preferred embodiment 
thereof, it will be apparent to those of ordinary skill in the art that 
many modifications may be made thereof within the scope of the invention, 
which scope is to be accorded the broadest interpretation of the appended 
claims so as to encompass all equivalent products and processes.