Laminator assembly

A laminator system for the continuous treatment and lamination of a plurality of flexible webs, with the system including the conventional adhesive applicator stations and laminator stations, with a drying chamber being arranged to dry or otherwise condition the applied adhesive films. The drying chamber is an annular enclosure having a generally inverted "U" configuration with access openings being formed at the base of each of the upright legs. Guide rolls are provided for creating a plurality of web paths through the laminator system, with the web paths including a plurality of generally parallel and concentric spans extending through the drying chamber. In addition to size reduction considerations, the drying chamber provides enhanced versatility for the laminator assembly, and simplifies solvent recovery.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a laminator assembly, and more 
specifically to a laminator system arranged for the continuous treatment 
of a plurality of flexible webs, such as polyethylene film or the like. In 
addition to the conventional adhesive application stations and laminator 
stations, the apparatus includes a drying chamber having the configuration 
of an inverted "U", and being provided with guide rolls for the 
simultaneous movement of multiple spans of the web being treated. 
In the design of laminator assemblies, particularly laminator assemblies 
which will be utilized for a variety of fabrication applications, 
versatility and interchangeability are desirable features. In addition, a 
reduction in the number of web leads and lead lengths are desirable 
objectives. The laminator system of the present invention provides these 
desirable characteristics along with an arrangement for efficient recovery 
of solvent from the system. 
SUMMARY OF THE INVENTION 
Briefly, in accordance with the present invention, a laminator system is 
provided which includes a plurality of unwind stands, and an arrangement 
of guides which moves the web from an adhesive applicator station through 
the drying chamber, and thence on to a laminator station. Upon leaving the 
first laminator station, the composite partially completed web is passed 
through a second adhesive applicator station, and then re-passed through 
the drying chamber in a direction counter-current to the initial path. 
Upon emerging from the drying chamber, the composite web having a 
conditioned adhesive film on a surface is then joined with a third film, 
and thereafter again passed through the drying chamber in a path parallel 
to the initial path and in the same direction. Upon emerging from the 
drying chamber, the composite web may be further treated by the addition 
of still another web, or alternately the application of a thermalstrip or 
the like thereon. 
The apparatus of the present invention is particularly adapted for use in 
the preparation of multi-layered laminates or webs which find utility in 
the fabrication of multi-wall bags or the like. It is appreciated, of 
course, that laminates, particularly those prepared from webs of flexible 
film find utility in a wide variety of applications. 
Therefore, it is a primary object of the present invention to provide an 
improved laminator assembly which is highly versatile, and adapted for 
multiple applications, and which is capable of continuously accommodating 
a substantial number of individual webs. 
It is yet a further object of the present invention to provide an improved 
laminator system for the continuous treatment of a plurality of individual 
webs, the laminator system utilizing a single drying chamber which 
simultaneously accommodates a plurality of spans of composite web 
materials. 
It is yet a further object of the present invention to provide an improved 
laminator system which reduces the number of web leads required, and in 
addition shortens the length of the individual leads.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In accordance with the preferred embodiment of the present invention, and 
with attention being directed to FIG. 1, the laminator assembly generally 
designated 10 includes base frame means 11 upon which are mounted a 
primary unwind stand 12, a secondary unwind stand 13, a tertiary unwind 
stand 14, and a rewinder or take-up stand 15. Disposed between the primary 
and secondary unwind stands 12 and 13 respectively are a plurality of 
adhesive applicator or coating stations, along with laminator stations, 
together with a drying chamber generally designated 16. As is apparent in 
FIG. 1, a plurality of guide means and the like are provided in order to 
define a path through which the various webs and composites thereof may be 
passed. 
In order to follow the progress of the individual webs through the 
apparatus, material from the primary unwind stand 12 is taken from roll 
20, and carried through guide rolls 21 and 22, as well as others, to the 
first applicator station such as the station generally designated 23. 
Applicator station 23 includes a film applying roller 24 and a leveling 
roller 24A which together function as a conventional roller coater 
applying a level or uniform film of adhesive to the surface of the web as 
at 25. The web is then carried by additional guide rolls such as, for 
example, guide rolls 26, 27, and others, wherein the web travels along a 
first plurality of spans such as the spans 29, 30 and 31, among others, 
thereby passing entirely through the confines of drying chamber 16, having 
entered chamber 16 through a first access opening 32, and emerging through 
second access opening 33. The web then passes from the drying chamber 16 
to the nip of a first laminating station generally designated 35 where the 
conditioned web surface such as at 36 meets the web being delivered to the 
system from the secondary unwind stand 13, such as web 37. Laminator 
station 35 is a conventional laminator station and provides the force and 
other conditions necessary for bonding the webs together to form a 
composite web. Upon leaving laminator station 35, the composite web passes 
through the second coating station generally designated 40 whereupon 
surface 41 of the web is coated from roller coater 42 and level roller 
42A, the web then continuing through a plurality of spans such as at 43 
and 44, in a counter-current direction from that of the first pass, until 
ultimately emerging from the dryer 16 and passing through the second 
laminating station generally designated 46. Laminating station 46 includes 
rollers 47 and 48 which provide the force and other conditions necessary 
for joining the composite web with material from the tertiary unwind stand 
14. 
Upon departing laminator station 46, composite web may either be passed 
directly through drying chamber 16 for a third pass, or may be provided 
with a heat sealing coat or thermal-strip at applicator station generally 
designated 50. Such thermal-strips are, of course, commonly applied to 
laminates and will be arranged in a pattern such as that indicated by the 
ultimate end use of the material. The then treated material passes over 
guides 51 and 52, among others, through spans such as spans 53 and 54 
until being discharged from the drying chamber 16 through access opening 
33, over guide rolls 56 and 57, and ultimately on to the pair of 
chill-rolls as at 58 and 59. Chill-rolls 58 and 59 are arranged in a 
flip-flop disposition depending upon the requirements of the product as it 
passes through the chill-roll area. Upon departing the chill-rolls 58 and 
59, web such as at 60 is taken up on rewind stand 15 in the form of roll 
61. 
Applicator Stations 
It will be appreciated that the coating or applicator stations may be any 
of the commercially available conventional varieties, including the 
following for example: 
gravure 
offset gravure 
kiss coating 
reverse roll coating 
smoothing bar coating 
mixer rod coating 
Thus, the coating system is not critical, but is one which is adpated for 
use in connection with the materials being treated. 
In certain applications, it is desirable to utilize a stripper for web 
treatment, and in the embodiment illustrated, such a stripper is shown as 
at 65. This station may be utilized, for example, for applying thermal 
strip which strip did not require extensive drying subsequent to 
application. 
Unwind Stands 
The unwind stands which are illustrated are also of the commercial variety, 
and are equipped with means for retaining a pair of supply rolls so as to 
accommodate changing of the rolls on a continuous and running basis. Such 
unwind stands are, of course, commercially available and recognized and 
utilized in the art with one such stand being shown in U.S. Pat. No. 
2,990,989. 
Laminator Stations 
Normally, a conventional laminator station may be utilized, including a 
pair of heated rolls forming a nip through which the materials to be 
joined pass. Adequate force is applied to accommodate the laminating 
operation. Laminating rollers of this type are, of course, commercially 
available. 
The Drying Chamber 
As has been indicated, the drying chamber 16 is one having an inverted "U" 
configuration with a pair of upright legs being coupled together with a 
cross-member at the top thereof. The drying chamber is provided with a 
plurality of guide rolls which move the web through the chamber on 
multiple passes, with the paths generated by the guide rolls for the web 
being generally parallel, one to another, and concentric. The drying 
chamber is provided with air inlet and exhaust ports to accommodate a flow 
of air for conditioning the adhesive film so as to provide for subsequent 
bonding of the film. The drying chamber normally provides a solvent 
removal operation for solvent-based adhesive films and the inlet air may 
be heated, if desired to accelerate the solvent removal. In the case of 
the thermal-strip, the drying chamber is used to addtionally condition the 
strip through exposure to heat, and ultimate solvent removal.