Paper sheets or webs with separable self-adhesive labels

The present invention relates to a process for the production of paper sheets or webs (1) with self-adhesive labels (2) separable from the paper plane, in which to a running paper web (5) a contact adhesive application (4) and a separating paper (3) are applied at least in the vicinity of the labels (2) and during the passage of the paper web (5) through a punching device (9) the labels (2) are completely punched out of the paper web (5) prior to the application of the contact adhesive (4) and the separating paper (3), wherein the contact adhesive (4) is always applied together with and on the separating paper (3) to the paper web (5) and wherein the punched out labels (2) are fixed in the paper web (5) until their fixing is taken over by the separating paper (3) coated with the contact adhesive (4).

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to paper sheets or webs with separable 
self-adhesive labels and in particular to a novel process for the 
production of such paper sheets or webs, in which, at least in the 
vicinity of the label, a contact adhesive and a separating paper is 
applied to a running paper web and the labels are punched out when the 
paper web passes through a punching device. Finally, the invention also 
relates to an apparatus for performing the process. 
2. Description of the Related Art 
EP-B1-175,719 discloses several processes for producing paper sheets or 
webs, particularly forms, with separable self-adhesive labels, which in 
the vicinity of the labels have an undesired, large thickness and/or in 
which the danger exists that, under heat and pressure action, contact 
adhesive will pass over and beyond the area of the labels into the 
surrounding marginal zone, which can lead to a sticking together. 
Admittedly in the processes of EP-B1-175,719 these disadvantages are 
avoided. However, the labels are not completely punched out of the paper 
web and instead remain connected to the latter by means of weakening 
lines, such as e.g. perforations. 
In a similar process, which is used in practice, in the vicinity of the 
labels initially a contact adhesive layer and separating paper portions 
are applied to a paper web. Only subsequently are the labels punched out, 
the paper web and the contact adhesive layer being punched through (wet 
punching through), but the separating paper on the back of the paper web 
is only prepunched. The labels remain fixed in the paper web, because the 
contact adhesive layer and the separating paper portions somewhat project 
over the surface of the labels on all sides. As the separating paper 
portions project over the contact adhesive layer on all sides, it is 
ensured that the contact adhesive does not pass out of the area of the 
separating paper and bring about a sticking together. 
However, in the last-described process the prepunching is particularly 
problematical and difficult. The setting up and adjusting of the 
corresponding punching device is complicated and time-consuming and is 
also difficult to keep constant over a long period of time. In order to be 
able to carry out prepunching from the production standpoint, thicker and 
therefore more expensive separating papers must be used than would be 
necessary for the intended use per se. However, thicker separating papers 
more particularly lead to an increase in the overall thickness of the 
paper sheets or webs in the vicinity of the labels, which makes more 
difficult the handling thereof during stacking, reeling or inscribing. 
The prepunching is made more difficult by the prior coating with the 
contact adhesive. The aqueous acrylic adhesive which is used in most cases 
wets the paper web, which leads to a reduction in the punching capacity. 
This can admittedly be avoided by a predrying, but the latter is 
expensive, energy-consuming and also endangers the flatness of the paper 
web. A laser printing run on the part of the customer can consequently be 
made more difficult or even impossible. 
SUMMARY OF THE INVENTION 
The main problem of the present invention is to provide a simple and 
economic process for producing paper sheets or webs with integrated, but 
completely punched out self-adhesive labels of the aforementioned type, 
which avoids the aforementioned disadvantages and can be performed using 
much thinner separating paper. In addition, an apparatus suitable for 
performing the process is to be provided. 
Thus, in the process according to the invention the punching is a dry 
through punching, which is only performed on the paper web prior to the 
application of the contact adhesive and the separating paper. Only 
subsequently is the contact adhesive applied together with the separating 
paper to the paper web. The punched out labels, i.e. no longer connected 
to the paper web are fixed in the latter at their original location until 
this fixing is taken over by the separating paper coated with the contact 
adhesive. 
Thus, in the process according to the invention no use is made of 
prepunching. According to the invention the punching out does not take 
place in the finished, so-called contact adhesive laminate, but instead by 
punching through solely in the paper web before the latter is brought 
together with the contact adhesive and the separating paper. 
Therefore the process according to the invention makes it possible to 
produce self-adhesive labels on separating papers with much smaller 
thicknesses than hitherto. Thus, e.g. silicone papers can be reduced from 
the hitherto conventional 80 g/m.sup.2 or at least 50 g/m.sup.2 to only 30 
g/m.sup.2. The thickness of siliconized films can be reduced from 50 .mu. 
to 20 to 25 .mu.. 
By means of the process according to the invention higher production speeds 
can be achieved and in particular the setting up times for the production 
machines are greatly reduced. 
The fixing of the punched out labels in the paper web between punching out 
and the application of the contact adhesive or separating paper preferably 
takes place electrostatically or by vacuum and namely either on one of the 
cylinders of the punching device or an endless conveyor belt moving 
together with the paper web. 
The separating paper is preferably drawn from a reel. The separating paper 
can be coated with the contact adhesive on the reel. However, the coating 
with the contact adhesive can also take place immediately prior to the 
application to the paper web. 
The paper web can be laminated in whole-surface manner with the separating 
paper, which is advantageous if it is only wished to produce self-adhesive 
labels. However, prior to the application to the paper web the separating 
paper can be cut to the approximate size of the labels. This is 
recommended e.g. in the case of forms, which in a relatively large paper 
surface only contain individual, comparatively small labels. 
According to the invention the contact adhesive is applied together with 
the separating paper. However, it must subsequently be joined so well to 
the label material that it adheres to the back of the label, when the 
latter is drawn off at the time of use. Following the removal of the label 
no contact adhesive must remain on the separating paper in the vicinity of 
the label. This so-called contact adhesive transfer can be assisted and 
sped up by exerting pressure on applying the separating paper. If the 
paper web, e.g. in a punching device with a rotating punching cylinder is 
deflected around the latter and the application of the separating paper 
also takes place on the punching cylinder, then the punch knives of the 
punching cylinder exert an increased pressure at the cut edges of the 
labels which, as explained, has a favourable influence on the contact 
adhesive transfer. However, the pressure exerted is much less than that 
during punching, so that there are no problems such as e.g. occur with 
prepunching. 
The paper sheet or a corresponding paper web and having at least one 
separable label produced by means of the process according to the 
invention is characterized in the claims of the present invention, the 
claims of the present invention also illustrate a preferred embodiment 
with an extremely thin and only very slightly bulky separating paper. It 
is a characteristic thereof that the separating paper and the contact 
adhesive application have no punching tracks.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Reference is firstly made to FIG. 1, which shows under a) a paper material 
form 1 having a marginal hole system and a label 2 separable therefrom. As 
can be seen in the sectional representation under b) (section A--A in FIG. 
1a), the label 2 is fixed in the form 1 by a separating paper portion 3 
projecting marginally over all sides of the label 2 and stuck to the back 
of the form. There is a contact adhesive layer 4 in FIG. 1, which also 
projects marginally at all sides over the label, but has a surface which 
is somewhat smaller than that of the separating paper piece 3. The contact 
adhesive of the contact adhesive layer 4 has on the paper of the form 1 or 
the label 2 a greater adhesion than on the separating paper 3. The contact 
adhesive layer on the back of the label 2 is consequently detached 
together with the label during the detachment of the latter from the 
separating paper 3, as is shown in FIG. 1c. 
In the apparatus according to FIG. 2 the paper web 5 passes from a reel 6 
initially between a punching cylinder 7 and a countercylinder 8 of a 
punching device 9. The desired labels 2 are thereby punched out of the 
paper web 5. After punching the labels 2 no longer have any connection 
with the paper web 5. From a further reel 10 is drawn a separating paper 
web 11 (e.g. a silicone paper or also a separating film) and is 
selectively coated with a contact adhesive 4 in a coating station 12. By 
means of a cutting device 13 individual separating paper portions 3 coated 
with the contact adhesive are cut from the separating paper web 11. The 
coated separating paper portions 3 are then laminated in a laminating 
device 14 onto the paper web 5 in the vicinity of the labels 2. The 
laminating device 14 here comprises on one side the aforementioned 
punching cylinder 7 of the punching device 9 and also a laminating 
cylinder 15. 
So that the labels 2 punched out of the paper web 5 during the passage 
between the punching cylinder 7 and the countercylinder 8 remain at their 
original position in the paper web 5 during the further movement thereof 
until they are fixed there by the laminated on separating paper portions 
3, they are temporarily fixed on the punching cylinder 7. For this purpose 
the paper web 5 is deflected around the same. After approximately a 
quarter rotation on the punching cylinder 5 the separating paper portions 
3 are supplied over the laminating cylinder 15. The punching cylinder 7 
fulfils the further function of acting as a counterpressure cylinder 
during the lamination process. The brief fixing to the punching cylinder 7 
in particular takes place electrostatically, the static electricity for 
this being produced by means of the elements 16. For vacuum fixing the 
punching cylinder would have to be provided with vacuum suction holes of 
approximately 1 to 3 mm diameter, which are periodically controlled for 
suction and release. 
In the example of FIG. 2 the paper web 5 is deflected by 180.degree. round 
the punching cylinder 7. However, fundamentally it would be sufficient to 
have a smaller deflection angle, the latter depending on the size of the 
labels and the diameter of the punching cylinder. 
The deflection of the paper web 5 and the fixing of the labels 2 could also 
take place round or on the countercylinder 8. The use of the punching 
cylinder 7 offers the advantage that at the instant of laminating on the 
coated separating paper portions 3, the knife edges of the punching 
cylinder bring about a certain additional laminating pressure in the 
marginal area of the labels, which has a favourable effect on the transfer 
of the contact adhesive from the separating paper to the labels. 
In FIG. 2 17 designates an endless conveyor belt for the supply of the 
separating paper web 11, whilst 18 is a drying device for the contact 
adhesive application to the separating paper web 11. The endless conveyor 
belt 17 is preferably so controlled relative to the movement of the paper 
web 5, that the separating paper portions 3 come to rest in a precisely 
correct manner on the same in the vicinity of the punched out labels 2. 
In the case of the apparatus of FIG. 3 there is no coating station 12 and 
drying device 18, because here the separating paper web is already coated 
with contact adhesive 4 on the reel 10. The contact adhesive coating is 
not continuous and is instead, as in FIG. 2, selectively interrupted. 
Thus, on the forms, the separating paper portions 3 can project 
surfacewise somewhat over the contact adhesive layers. In addition, the 
cutting device 13 does not also have to cut through the contact adhesive. 
Otherwise there are no differences between FIGS. 2 and 3. 
In FIG. 4 the temporary fixing of the labels 2 does not take place to the 
cylinder of the punching device 9, but to an endless conveyor belt 19 
especially provided for this purpose. The latter is deflected on the 
cylinder 8 of the punching device round a reel 20 having a very small 
diameter compared with the cylinder 8, so as to be able to take over the 
labels 2 for as long as they have not yet been completely punched out of 
the paper web. The distance between the reel 20 and the bottleneck between 
the two cylinders 7,8 of the punching device 9 should be smaller than the 
extension of the labels 2 in the longitudinal direction of the paper web 
5. Once again the labels are fixed to the endless conveyor belt 19 
electrostatically. Also in FIG. 4 the separating paper web is precoated 
with contact adhesive on the reel 10. The contact adhesive application is 
in this case continuous and does not have any gaps as in the case of FIG. 
3. 
The apparatuses according to FIGS. 2 and 3 could naturally also be operated 
with a continuous contact adhesive application to the separating paper 
web. 
Finally, for producing individual sheets or forms from the paper web 5, 
they would naturally also have to be trimmed, but this is not shown in the 
drawings. However, the paper web can also be left unchanged.