CA1084825A

CA1084825A - Method of and apparatus for joining flexible fastener strips to film

Info

Publication number: CA1084825A
Application number: CA276,768A
Authority: CA
Inventors: Andre M. Herz
Original assignee: Minigrip Inc
Current assignee: Minigrip Inc
Priority date: 1976-10-29
Filing date: 1977-04-22
Publication date: 1980-09-02

Abstract

ABSTRACT

A method of and means for attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for separable interlocking with a complementary second flexible separable fastener profile, comprising the step of and means for moving the web and the fastener strip substantially continuously at the same high speed convergently toward one another and joining the interface surface areas of the web and fastener strip, the step of and means for effecting guidance of the interlocking profile and thereby the moving fastener strip in a predetermined path into said joining with the moving web, the step of and means for just prior to the joining of the high speed convergently moving web and fastener strip sub-stantially continuously applying a thin substantially uniform layer of adhesive to a substantial width of at least one of the interface surface areas and comprising discharging the thin adhesive layer substantially in the direction of move-ment of the web and strip directly onto the one surface area from a nozzle having a narrow slit-like elongated orifice disposed close to the joining and extending with its length transversely parallel to the interface surface area, and the step of and means for pressing the web and fastener strip and adhesive layer together at the joining and effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in the high speed movement.

Description

1~48Z5 SPECIFICATION
This invention relates to method of and means for joining separable flexible fasteners to plastic film or web, and the product obtained according to the method.
For various purposes, and especially for the manufac-S ture of plastic bags, mating profiled fastener strips are joined to plastic web or film, both the fastener strip and the film being produced by extrusion of suitable plastic material through suitable dies. The joined fasteners and film may be made into various desirable products, and find extensive use in the manufacture of bags, the fasteners being of either the type which can be joined to provide a closure by finger pressure or by means of a slider, the profiles of the fasteners being elastically deformable for this purpose.
Bags obtained by use of such material may comprise two lS thin f-llm walls joined along opposite sides to form the~bular body of the bags and if desired a third side constituting the bottom of the bag may also be closed, or such bottom may remain open until the bag has been filled with a contents such as merchandise.
Two contiguous edges of the bag walls are separable from each ZO other along the end or side opposite the bottom in order to provide an access opening to the interior of the bag, and the separable edges have therealong complementary closure profile fasteners capable of being joined with each other by pressure exerted along the fasteners strips or by means of a slider. Various arrange-Z5 ments of the mating profiles may be provided, as will become more apparent hereafter.

4~Z5 Bags of the type described have been employed for packaging and retailing of mass consumption products such as food, dothin~, tools, etc., and are generally of a transparent plastic material to permit observation of the contents.
According to one prior method of manufacture, the plastic film and fastener strips are formed in a common extrusion operation. This is a relatively slow process and difficult to implement, primarily because of the great difference between the thickness of the film and the mass of the fastener strips.
Generally in that method the material of the fastener strips and the film is the same.
According to second prior method of manufacture, the film and the fastener strips are extruded separately, generally at di~ferent speeds and under different control conditions as to temperature, and the like, and the fastener strips are then fixed to the film by fusion, either by direct application of heat or by ultrasonic welding, and the like. Generally, it is necessary for the film and the fastener strips to be made from the same material because it has been found practically impossible to fuse ZO two different plastic materials to one another.
As to either of the two prior expedients noted, a great disadvantage is that it is impossible o choose the plastic ma~erial most appropriate for the mechanical or optical qualities desired in either or both of the fastener strips and the film. For example, Z5 it is impossible to produce bags wherein the walls are made from polypropylene, which is particularly advantageous because of its : ~ .

transparency but lacking in elasticity, and form the fastener strips from polyethylene which is a more opaque material but advantageous because of its suppleness and resilience.
Other disadvantages of the fusion or welding process are that where the fastener strips are welded onto folded web, as in bag making, it is necessary to have an insulating bar disposed between the film plies so that they will not be welded together.
The presence of such an insulating bar creates difficulties in the apparatus and imposes friction factors preventing operation at high speed. Also, the welding temperature is very critical because necessarily the film is thin and the profile fastener strips are thicker sothat if the temperature is too low attachm~nt is insecure and if it is too high there is the risk of burning the plastic material. Thereafter, upon cooling, wrinkling of the thin filn occurs due to the more rapid cooling of the fi~n than the greater mass fastener strips, so that the product such as a bag has an unsatisfactory appearance. In addition, it is impossible to attain attachment of the fastner strips across their entire width because the area behind the profile lock cannot be welded ~0 onto the film aligned with said profile, but only the web flanges extending along the profile, can be welded to the film whereas it is the profile which is directly subjected to the strains of opening or closing the fasteners. Finally, in some instances the walls of the product such as bags bear imprinted indicia such as Z5 trademark of the product, and the like, and during welding there is the risk of damaging the inscriptions and the ink may come off : :' ?~fL~

onto the clamping mechanism. It has heretofore been necessary for manufacturers to accommodate themselves to these disad-vantages which have been considered inescapable and inherent in the method, and so far as I am aware no remedy has heretofore been suggested.
It is, accordingly, an important object of the present invention to overcome the disadvantages, deficiencies, inefficiencies, shortcomings, and problems inherent in prior methods and apparatus and to provide a continuous and rapid process for joining and attaching profile fastener strips to film web traveling at high speed and intended, for example to provide the walls of bags or other articles and in particular to permit choice of different kind and thickness and optical and mechanical properties of the film webs and of the fastener strips.
Pursuant to the invention a new and improved method of and means are provided for applying adhesive continuously to and between the interfaces of prefabricated fastener strips and pre-fabricated webs, and to which the adhesive is applied while the webs and the strips are traveling at high speed and preferably substantially continuously. By the expression "high speed" it is intended to mean a speed substantially greater than has been practicable when practicing the welding method, and in particular speeds according to the present invention on the order of at least lO0 meters per minute. By the expression "substantially continuou~ly"
it is intended to mean that a cement or adhesive such as plastic material of the type called "hot melt" is deposited in a .~' continuous fashion while the strip or strips and the film web or webs are in a continuous motion, even though the film webs and strips may possibly have to be stopped periodisally as for example to replace supply reels or rolls, requiring a corresponding halt in the adhesive supply while supply reel replacement is in progress.
The invention enables the high speed joining of pre-fabricated extruded flexible separable fasteners whether of the pressed together or slider fastener type to prefabricated plastic or other types of fllm or web material by virtue of the elimination of the need for fusing of the fastener and web materials.
Joining of the film web and the fastener strips is effected by moving them continuously into engagement with one another, and at a location upstrearn from the point of meeting applying adhesive continuously either to the film or web but preferably to the fastener strips. The bonding agent such as glue or adhesive is preferably deposited on the profiled fastener strips because they are thicker than the film or web and have greater firmness, and depositing of the bonding agent does not risk causing even a slight deviation from the path of movement due to any pressure that may be encountered in application of the bonding agent.
The invention permits choice of the most appropriate material for the film and for the profiled fastener strips, disregarding differences not only in the character of the material, but also in the thickness of the film or web and the fastener strips.
It is practical to select polypropylene for the film and polyethylene for the fastener strips. It is even practical to utilize a film or web of a non-weldable material such as paper, a composite film of plastic material and paper or aluminum foil, the fastener strips being selectively attachable to the plastic material face or to the non-plastic material face of the web. Thereby, large numbers of selective possibilities and various film fastener com-binations are obtainable.
The invention eliminates the necessity for the stop and go method of welding the film to the fastener strips that has often been necessary in the hot welding clamp process, and to provide a method and apparatus according to which any pressure that may be desirable to effect bonding can be continuous and carried out at high speed.
Inasmuch as the adhesive can be applied to the entire width of the fastener strips including the area behind the locks or profiles, attachment of the strips to the film or web over their entire width is effected, thereby resulting in a more secure attachment and improved mechanical firmness of the fastener profiles.
In addition, where imprinted film is utilized, there is no risk of deterioration of the printing when the present invention is utilized, in contrast to the hot welding technique heretofore ~0841!325 employed .
According to one manner of practicing the invention, the fastener strips may be bonded by cementing to the film while the film is in a relatively flat condition, and the film subsequently folded along a fold line parallel to the axis of movement of the film and fastener strips, so as to bring the fastener strips into relative position ~or interlocking of the fastener profiles. In this way either two separate complementary profiled fastener strips may be adhesively secured in parallel relation adjacent to the intended fold line, and bags made from such product after folding having open bottoms so that they can be filled and when sealed closed across the bottom form a complete enclosure so that the contents are tamperproof and access into the enclosure can only be obtained by cutting the bag. Al~o the profiled complementary lS fastener strips can be adhesively bonded along opposite edges of the film and the film then folded to provide a closed bottom, open top bag so that filling may be effected through the opening between fastener strips the profiles of which may then be inter-locked to effect a closure for the bag. In addition, two profiled fastener strips which have their profiles joined together in locking relationship may be respectively adhesively fastened along parallel traveling adjacently spaced films, which may then be folded toward one another to make bags.
The invention also lends itself to the attachment of one or a plurality of strips containing complementary profiles wherein said strips can be folded longitudinally so that the profiles are 101348;~5 interlocked or are ready to be interlocked with the profile strips being secured by means of adhesive layers at their interfaces along adjacent lateral edges to two film layers. Bags made from this assembly would be of the tamperproof type since it is necessary to cut the fastener strips along their longitudinal fold line between the profiles in order tocpen the bags.
Numerous and varied other arrangements of flexible separable fastener strips and film or web (the terms "film"and "web" wherever used herein being understood to mean any suitable pliable sheet material to which flanged, profiled, separable flexible fast~ers can be advantageously applied) are obtainable due to the advantageous adaptability of the adhesive attachment of the fastener strips to the webs, as will become apparent as the description proceeds.
Adhesive attachment of the fastener strips may be effected where the complementary profiles are on separate strips, with said separate profile strips being fastened together so as to facilitate adhesive attachment of the fastener strips to the web material, or where the complementary profiles are on the same ~0 strips which are then folded to bring the profiles into engagement thereby providing numerous desirable combinations.
The profiles of the strips may be employed to assist in guiding the st~ips into position for adhesive attachment.
~dhesive attachment of the strips to the web may be ~5 effected at high speed and the resulting assembled product rolled up on supply reels, for subse(luent processing into bags or other g s articles and which may be effected at slower speed. For example, whereas cemented assembly of strips and film or web may be effected in one line, due to the high speed of production, the resulting output of the one line may be rolled up in reels and S utilized in a plurality of bag forming and/or filling lines, thus attaining high productivity at low cost.
The invention results in a new and improved product comprising a web material having the flexible fasteners cemented thereon, and new and improved bags made from said web material with cemented profiled flexible fastener strips thereon.
The invention provides a method of attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for separable interlocking with a complementary second flexible separable fastener profile, comprising moving the web and the fastener strip substantially continuously at the same high speed convergently toward one another and joining the inter-face surface areas of the web and fastener strip, effecting guidance of the interlocking profile and thereby of the moving fastener strip in a predetermined path into said joining with the moving web, just prior to the joining of the high speed convergently moving web and fastener strip substantially con-tinuously applying a thin substantially uniform layer of adhesive to a substantial width of at least one of said interface sur-face areas, and comprising discharging the thin adhesivelayer substantially in the direction of movement of the web and strip directly onto said one surface area from a nozzle having a narrow slit-like elongated orifice disposed close to said joining and extending with its length transversely parallel to said interface surface area; and pressing said web and fastener strip and adhesive layer together at said joining and effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and ~ -10-fastener strip continue jointly in said high speed movement.
The invention also provides apparatus for attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for interlocking with a complementary second flexible separable fastener profile, means for moving the web and the fastener strip at high speed and substantially continuously convergently toward one another to join the interface surface areas of the web and fastener strip, means for substantially continuously applying a thin layer of adhesive to at least one of said interface surface areas, and means for effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in said high speed movement.
Other objects, features and advantages of the invention will be readily apparent from the following des-cription of certain representative embodiments thereof, taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which:
Figs. la and lb demonstrate one manner of practicing the method according to the present invention;

Figs. 2a and 2b show another manner of practicing the method of the invention, utilizing a single closure strip having two complementary interlocking profiles thereon;

Figs. 3a and 3b show a further manner of practicing the invention utilizing multi-profile closure strips;

-10a-:~;

Figs. 4a and ~lb show still another manner of practicing the invention with multi-profile closure strips;
Fig. 5 discloses yet anotlher modification in the practice of the method of the invention;
Fig. 6 illustrates a still further modification in the method showing how two pairs of coupled profile strips may be used for attachment to the film after folding of the film;
Fig. 7 is an isometric, scnematic view of a machine for practicing the method according to the present invention;
Fig. 8 is an isometric fragmentary schematic illus-tration showing guide means for two interlocked profiled fastener strips, and which may be used on the machine in Fig. 7;
Figs. 9a, 9b, 9c and 9d are more or less schematic cross sectional views showing spaced parallel films onto the inside or confronting faces of which profiled fastener strips are adhesively secured in accordance with the present invention, and which are especially useful for fabrication of bags;
Fig. 10 represents a product according to the invention comprising a profiled fastener strip adhesively secured on a ~0 protective film;
Fig. 11 is an isometric fragmentary sectional elevational view showing a modification in the method and apparatus for joining a fastener strip to a film or web utilizing the profile as guiding means for the strip;
~5 Fig. 1~ is a top plan view of the assembly in Fig. ll;
and 1~48Z5 F ig. 13 is a fragmentary sectional detail view showing an adjustable guide for coupled profiled flcxible fasteners adhe-sively secured tO film or web material.
In Fig. la, a thin film web 1, for example extruded polypropylene, is advanced in a continuous fashion at high speed along the direction of its longitudinal axis, namely a direction perpendicular to the plane of the drawing. Parallel thereto, and in the vicinity of each of the free edges of the film 1, two resiliently flexible separable closure or fastener strips Z and 3 are advanced at the same speed, one of which has a male inter-locking profile Za and the other a female interlocking profile 3a, and both of which have the customary attachment flange structure on which the profiles are integrally carried. These two strips are also of plastic material, for example extruded polyethylene.
A layer 4 of an appropriate bonding medium, i. e. adhesive, which may be of the type commonly referred to as "hot melt" is deposi-ted in a continuous fashion on those flanges or faces of the strips which are opposite their profile, and those faces are applied and adhesively secured to the film 1. Then, in a first stage, the film ~0 is folded along its longitudinal axis, represented by the broken line 5. A folded film such as the one represented in Fig. lb iF
then obtained with profiles Za and 3a being brought into facing relation to one another and being eventually interlocked. After that, in a second stage, the two opposite walls 6 and 7 are ~5 transversely cut and joined, for example by welding, at predeter-mined intervals corresponding to desired bag widths. Thereby, -lZ- ;

bags with a closed bottom are obtained. It may be noted that in the welding procedure the ends of the closure strips 2 and 3 are also welded together at the same time as the walls 6 and 7 since they are opposite one another.
In Fig. 2a, a variation is schematically represented, according to which a single fastener strip 8 is utilized, made in one piece, for example by extrusion, but w~ich comprises two complementary interlocking profiles 8a and 8b. On the strip flange, whose face is opposite to the profiles, a thin layer of adhesive is deposited by discharging the adhesive layer substantially in the direction of high speed movement of the strip 8 and a film web l0 from an elongated narrow slit-like orifice of a nozzle 9 fed, in any preferred manner not shown, from an adhesive reservoir.
As shown, at least the transversely elongated narrow orifice of the nozzle 9 is located parallel to the interface areas of the strip 8 and the film web l0 and as close as practicable to the convergent joining of the interface area of the strip 8 with the interface area of the web l0, and the thin layer (e.g. l/lOmm thick) of adhesive applied through the nozzle orifice extends between the sides of the strip 8 fully under the profiles 8a and 8b. The adhesive carrying strip face is brought into contact with a prefabricated plastic film web 10, along the traveling or longitudinal axis of the film, with both it and the pre-fabricated strip 8 traveling at the same high speed (in the direction of the arrow ll)~ For effecting high speed movement and guidance of the film l0 and the strip 8, a rotary pressure roll 12 has been provided underneath the strip and above it a rotary pressure roll 13.

~X~ -13-~'-8~5 The latter includes two annular grooves 14 which provide for the passage of, and effect straight guidance of the profiles 8a and 8b.
Then the film 10 and the strip 8 are folded along the axis of the film, narnely along a longitudinal central line passing between the two profiles, as a result of which a folded film with two opposite walls 15, 16 is obtained, such as that which is represented in Fig. 2b. The broken line 17 indicates the fold line.
The two profiles 8a and 8b can be interlocked at the time of the -13a-48;~

folding of the film, and more particularly Lhe folding of the two walls 15, 16 against one another. Consequently, after the operation of transverse severance and joining of the walls 15, 16 at predetermined spaced intervals, separate bags with an open bottom 18 are obtained, and through which open bottom they can be filled. It is to be noted that the bags obtained in this manner will have at the end opposite the bottom, a security closure, corresponding to the central section of the strip 8 and which the user will have to cut before having access to the fastener profiles in order to separate them, and then to the contents of the bag.
In order to facilitate such separation it may be preferred to provide one or two lines o~ weakness extending along said central part of the strip.
In Fig. 3a, another variation has been represented, according to whi~h a fastener strip 21 comprising two noncom-plementary (for example, of a female type) interlocking profiles Zla and Zlb are conveyed, in continuous transport, onto one face of a film web 19 along the longitudinal traveling axis of the film (represented by the interrupted line 20), while at the same time Z0 applying on the same face of the film along each of its longitudinal edge portions respective fastener strips ZZ comprising interlocking profiles Z2a and ZZb respectively, said profiles being of the male type and complementary to the profiles Zla and Zlb. Of course, before effecting attachment contact between the film 19 and the Z5 flange faces of the strips 21 and 2Z which are opposite their profiles, there has been deposited on these faces a thin layer of 1~48~5 adhesive Z3. Then the film 19 is folded along two longitudinal lines Z4 intermediate the attached strips Z1 and ZZ so that the profiles Z2a and ZZb come opposite the profilcs Z1a and Zlb and may be interlocked with them. Then, if desired and prererably in a continuous fashion, the film 19 and the central portion of the strip Z1 may be cut longitudinally along axis ZO by means of a knife Z5. After transversal cutting and joining of the film and the strips, two sets of separate bags with closed b~ttoms are obtained, analogous to those in Fig. lb or, if the longitudinal cutting is not performed, double small bags of the"pocket-book"
type are obtained.
In Fig. 4a, yet another variation has been depicted7 according to which fastener strips Z7 and Z8 while in continuous transport, are applied and fixed, b~y cementing, i. e., adhesively, onto a film web ~6 along two longitudinal lines Z9 of said film, situated in substantial spaced relation at opposite sides of its longitudinal axis 30. Each strip Z7 and Z8 consists of a male profile, respectively Z7a and Z8a, and a female profile, respec-tively Z7b and Z8b. The film Z6 and the strips Z7 and Z8 are ZO then longitudinally folded along the lines Z9 so that the profilesZ7a and Z7b on one side, and Z8a and Z8b on the other side come opposite each other and may be interlocked (Fig. ~b). After that ;
fastener carrying film Z6 is adapted to be transversely sealed and cut longi~udinally at suitable interv~s along its axis 30 by a ZS knife 31. In this way, two sets of bags with an open bottom can be obtained, as in the case of Fig. Zb.

4~25 In the embodimcnt of Fig. 5, a different proccdure is followed, in that one of the flexible fastener strips, for example a strip 32 with male profile 3Za is coated with a layer of adhe-sive on the flange face which is on the same side as the profile, and this strip is then cemented onto one of the longitudinal edges 33 on the outer side of an already folded film web 34 so that the profile 32a projects toward the opposite edge 36 of the web 34.
Concurrently a fastener strip 35 with female profile 35a is cemented on the inner side of the opposite longitudinal edge 36 of the film web 34. Here again, separate bags with a closed bottom may be obtained, whe rein the fastener strip 32 will be visible from the exterior, independently of the fact that the walls of the bags may be transparent.
Means for making bags generally according to the embodiment of ~ig. 5 with some desirable variations, is repre-sented schematically in Fig. 6. Therein, a wide film web 37 is initially folded continuously along two longitudinal lines 38 at opposite spaced distances from its traveling axis, so that the two longitudinal free edges 39 of the film are directed toward each other in parallel relationship. A fastener strip 41, comprising two adjacently spaced parallel noncomplementary interlocking profiles 41a and 41b, is applied and cemented onto the continuous internal face 40 of the lower fold of the film web. At the sams time respective fastener strips 43 with interlocking profiles 43a and 43b complementary to the profiles 41a and 41b are applied and cemented along the edges 39 of the film and on the upper 1~4825 external faces 4Z of the upper separated folds of the film web.
Preferably, interlocking of the profiles 41a to 43a and profiles 41b to 43b is accomplished before application and cementing of the strips onto the film web 37. In order to effect guidance and pressing together of the film web and the fastener strips, a rotary pressure roller 44 has been provided beneath the film 37 and a rota1^y pressure roller 45 above the film and the strips 41 and ~3. The roller 45 has annular grooves 46 providing opposed spaced guide surfaces with which the sides of the profiles coop-erate in guiding the strips accurately into the attaching position on the film 37. On either side of each of the grooves 46, the roller 4S presses the attachment flange portions of the fastener strips 41 and 43 and the film web 37 against the roller 44 to effect thorough bonding of the strips to the web, in the nip of said rollers. Three delivery nozzles 47 are provided for apply-ing adhesive simultaneously to the faces of the flanges of the strips which are to be secured to the film. When the cementing ~ep has been completed, a longitudinal severance cut along the .
film 37 and the strip 41 is effected, substantially in the middle Z0 of the lor.gitudinal cementing area 48. As a result, after trans-versal seals and severances of the united assembly, two sets of bags with a closed bottom of the type represented in Fig. 5 are obtained at a high speed production rate.
In Fig. 7 apparatus has been represented schematically Z5 for practicing the method according to the invention at high speed.
The machine represented is supplied with a plastic film web 49 8;~ ~

unrolling in a continuous fashion and at high speed from a reel not shown~ The film a,9 is folded by mcans of a usual triangular folder device 50 to form two folds 51 connected by a fold line 5Z. The two folds 51 progressively approach each other to finally join each other at two guidance rollers 53 which extend horizon-tally startmg at the upper point 54 of the folder 50. Two rollers 55 and 56 cooperate to guide the film 49 onto the folder 50.
In additiors, the apparatus is supplied from reel means (not shown), with profile carrying fastener strips 57 and 58, whose comple-mentary profiles are interlocked in such a way that these two strips act like a single strip 57-58 thereby presenting smooth flange surfaces on both sides of the interlocked profiles. The strip 57-58 passes over a roller 59, and then between the two rollers 53 in such a way that it engages between the two free edges 60, which face each other, of the two folds 51 where these come together. In this way, and very conveniently, the strip S7-58 is sandwiched between the longitudinal free edges 60 of the folds 51 of the film 49.
Upstream from the point where the fastener strips Z0 57-58 joins the two folds 51, that is to say, ahead of the rollers 53, two adhesive delivery nozzles 61 and 6~ are supported by a fixed support 63, as is represented fragmentarily in Fig. 7.
These two nozzles are supplied with a liquid adhesive in any preferred n~anner (not shown), for cxample by flexible tubing joined to a reservoir of heated liquid adhesive, the tubing and reservoir being preferably insulated in order to avoid premature 1~4825 cooling and polymc:rizatioll of the adhesive. The nozzles 61 and 6~ discharge adhesive onto the respective smooth surfaces of the opposite flange faces of the strips 57-58 in such a way that said adhesive is spread uniformly, proportionately and in a thin layer on these two surfaces. Thereby, adhesion of the fastener strips 57 and 58 to the internal faces of the folds 51 along their free edges is attained. The film thus folded and provided with the two closure strips 57 and 58 may be finally rolled up on a reel 64, or may be introduced into a welding machine for forming into bags.
It may be observed that all the operations which have just been described in connection with the apparatus of Fig. 7 can proceed continuously and at very high speed, without any interruption nor any slowing down in the movement of the film 49.
This speed can attain values on the order of 200-300 m/mn and is considerably greater than that which can be attained with machines of thetype for attaching the closure strips by welding.
The production speed is so great that a plurality of the reels 64 of product produced by means of the Fig. 7 apparatus has to be processed by several standard slower operating bag machines working in parallel and effecting the operations of transverse welding and severing at regular intervals, of the folded web and the clos~ire strip assembly. As a result individual bags of the type in Fig. lb are produced at a high production rate.
~5 The machine represented in ~ig. 7 is desirably provided with means for guiding the strips 57-58 between the nozzles 61 10~2~
and 62. Such means have bcen depicted scparately in Fig. 8, so as not to complicate Fig. 7. The nozzles 61 and 6~ are slightly vertically offset in relation tO each other, and the guide means are arrangecl to assure an accurate lateral guidance of the strips 57-58 as well as to be able to pivot around a horizontal axle shaft 65 situated at an intermediate level between the nozzles 61 and 6Z so that the strips can be simultaneously deflected and removed from the discharge field of the orifices of the two nozzles at the moment the machine stops. This prevents the relatively elevated temperature at the nozzles from deteriorating the halted strips 57-58. To accomplish this, the guide means as schematically represented may comprise two guide plates 66 connected by a bridge-like cross-piece 67 fixedly connected to the shaft 65 and having between them a gap 68 for the passage of the releasably interlocked profiles 69 of the strips. The adjacently spaced edges of the plates 66 are positioned between the slightly separated flanges of the strips 57 and 58, which provides for excellent guidance of the strips and enables separating the strips - sufficiently from the two nozzles 61 and 6Z upon rotation around ~0 the axis of the shaft 65. This rotation can be automatically controlled, for example by means of a solenoid whose armature 70 is coupled to a flange 71 of the bridge-like cross-piece 67.
Other guidance means could be provided to fulfill these same funct ions.
~5 In Figs. 9a to 9d other variations of product capable of being obtained in conformance with the invention have been -~0 -~48~5 represented in cross-section. According to these variations, the interlocking profile fastener strips, preferably already interlocked, are not secured between t~ two folds of a film as in other modifications described herein but rather are secured between two separate films 72-73, which are transported parallel to each other.
In Fig. 9a the two films 7~-73 have the same width:
Two complementary scparably interlocked profile fastener strips 74, 75 are attached therein by cementing them to and between the fadng surfaces of the films. The strip 74 comprises a male profile 74a and a female profile 74b which are interlocked.
The strip 75, similarly, comprises a male profile 75a and a separably interlocked female profile 75b. The strips are folded longitudinally between the two profiles thereon, with fold of the 1~ strip being directed ou~ward relative to the assembly.
It is thus seen that after the longitudinal severance of the two films along their common longitudinal axis and the trans-verse welding and severance, two sets of bags with an open - bottom end will be obtained, and with a tamper-proof closure at ZO the other, top end. In fact it will be necessary for the user to sever the strips 74, 75 between their profiles in order to have access to the profiles and to disengage them.
Fig. 9b differs from Fig. 9a in that two separated profile strips, respectively 76a-76b and 77a and 77b are used.
Here also, two sets of bags with an open bottom will be obtained, but witllout a top end tamper-proof closure.

~848Z5 In Figs. 9a ~nd 9b, the profiled strips ~re adhesively attached along the lateral edges of the two films.
In Figs. 9c and 9d, by contrast, the profiled strips are attached on the longitudinal central area of the two films 7Z and 73 at opposite sides of the common longitudinal axis.
The film 7Z may be narrower than film 73. In Fig. 9c, two pairs of separate strips 78a, 78b, and 79a, 79b are provided.
In Fig. 9d, a single profile strip is cemented onto each film, with strip 80a havingtwo male profiles and the other strip 80b having two complementary female profiles. In these two forms, after longitudinal cutting of the two films along their common axis, and transverse joining and seiJerance of the films and strips, two sets of bags with an open bottom and offset edges will be obtained. Th~ offset edges facilitate separation of the two walls of the bags during the process of opening or filling them.
It may be noted that the four immediately preceding embodiments in Figs. 9a-9d afford the advantage of selectively providing the films 7Z and 73 in different colors.
Z0 As has been indicated hereinbefore, t~ present invention is not only adapted for the fabrication of bags but is also adapted for other uses. As represented in Fig. 10, another type of product capable of being manufactured pursuant to the invention, comprises a flanged plastic fastener strip 81, for Z5 example made of polyethylene, provided with two interlocking profiles, 8Z, in the form of ribs and grooves, and with a band zz of pressure sensitive adhesive 83 deposited thereupon in line with the profiles, but on the back face of the strip 81 and opposite said profiles. The adhesive 83 similarly to precedingly described embodiments can be deposited in a continuous fashion during longitudinal transport of the strip. The layer of adhesive 83 is covered with a protective backing 84 which may be a paper strip web and which can be readily stripped from the fastener strip by the user before use. A profiled fastener strip of this type, after removal of the protective paper strip, can then be fastened onto any appropriate surface such as a wall by a simple application of pressure.
One can then join to this strip any product provided with complementary profiles, for exarnple a sheet of plans, a curtain element or something else, the advantage of such a product being that it is easy to put in place and remove, by simply interlocking the profiles of the strip and the complementary profiles of the product, which may also have been equipped with said fastener strips in the same manner by means of pressure sensitive adhesive.
In Fig. 11 and 12 a device 85 is schematically depicted which is especially suitable for attaining accurate placement and attachment of a flanged flexible separable fastener strip 86 onto a web 87 by means of adhesive 88 while the fastener strip and web are in high speed concurrent forward movement indicated by the directional arrows. For this purpose, the web 87 which may be of any preferred material, whether extruded plastic film or non-plastic or a combination of a plastic and non-plastic materials, is supported and travels along a member 89 which may be flat as 4~325 shown or may comprisc a roller, if preferred. For guiding the fastener strip 86 convergently toward the web 87, a member 90 is supported by means of a suitable frame 91 in such relation to the support and guide 89 that an oblique surface 9~ facing toward the member 89 will receive and guide the flange body portion of the fastener 86 to meet the web 87. ~or accurate lateral guidance of the fastener strip 86, a longitudinal guide groove channel 93 in the guide member 90 receives a profile 94 that is integral with ~he strip 86. Side walls 95 in the groove 93 provide spaced guide surfaces between which the profile 94 is guided in fairly close clearance relation so as to move freely but with substantial accuracy into the longitudinal position desired on the web 87. It will be understood that although the profile 94 is shown as of the female form, it may as well be a male configu-ration of profile, and where desired a similar device may be provided or simultaneously applying a fastener strip having a mating profile to the same web at a different location, or the profile 94 may be of the multi-hook and groove-type, or two or more of the grooves 93 may be provided in the member 90 to ~o handle a corresponding number of the profiles on the same or different strips simultaneously, all as preferred for any particular intended purpose.
Adjacent to convergence of the fastener strip with the web, and preferably adjacent to the rear end of the member 90, ~5 a thin layer of the adhesive 88 is:applied by means of a nozzle 97 to either or both of the interface s~lrface areas 96 of the strip -~4 -1~48i~

86 and the wcb 87 but preferably to the back of the strip 86 for reasons previously discussed herein. The nozzle 97 may be supported by the frame 91 substantially as shown, and it may be supplied with fluid adhesive from a suitable source through a S duct 98. In order to avoid lateral flow of the layer strip of the adhesive 88 beyond the longitudinal edges of the strip 86, the nozzle orifice 99 is substantially accurately located and dimensioned and the rate of adhesive flow is controlled so ~hat width of the adhesive layer is narrower than the width of the strip 86 and sufficiently spaced inwardly from the longitudinal edges of the strip, at least at the point of application from the nozzle orifice 99 so that even though there may be some lateral migration of the adhesive 88 before it i s set, none cf the adhesive will escape beyond the longitudinal edges of thestrip 86~ This assures freedom from fouling of the device 85 or other parts of apparatus wi~h which the d2vice 85 may be associated. It will be understood, of course, that the velocity and character of the adhesive 86 applied by means of the nozzle 97 will be controlled to avoid excessive extrusion of adhesive to the traveling strip 86 and web 87 and to X0 apply just the optimum quantity of adhesive to serve the purpose.
Where it is desired to produce bags in which a pull-apart separable fastener closure 100 (such as is illustrated in Fig.
13) is secured to bag wall pane~; 101, a guide device 10Z may be employed for efficiently guiding the fa~ener assembly b~fore or Z5 after or during application of layers of adhesive 103 for affixing flanges lQ4 and 105 of the fastener assembly to aligned marginal -~5 -portions of the bag wall panels 101. The layers of bonding adhesive 103 are desirably sufficiently narrower, as shown, than the distance between the edges oI the webs 101 and the edges of .
the flanges 104 and 105 to avoid lateral escape of the adhesive layers beyond the edges of the webs and flanges. The fastener 100 may comprise complementary extrusions in which the flange 104 has along its outer edge a coextensive lip-like pull flange extension 106 with a multi-hook and groove separable fastener profile 107 hingedly and integrally connected at juncture of the flange 104 and extension 106 and normally turned back as a flap along the inner face of the flange 104 and separably coupled to a complementary rib and groove profile.108 integral with Lhe flange 105 and providing a longitudinal shoulder 109 facing in spaced relation toward the adjacent edge of the associated web 101. A pull flange extension 110 extends from the profile 108 in spaced preferably parallel relation to the pull flange. 106.
Construction and arrangement of the device 10Z is such that not only will it substantially accurately guide the separable fastener assembly 100, but will accommodate desired variations Z0 in width and thickness of the fastener 100; For this purpose, the device 10Z comprises a guide plate 111 which may be fixedly connected to a rigid support 11Z which may also serve as a back-up and alignment control for an adjustable plate 113 in spaced coopera~:ive and preferably coextensive relation to the companion Z5 guide plate 111. A shoulder 114 on the guide plate 111 is adapted to oppose the fastener profile shoulder 109. A width gauge and 111)~48;~:~

guide element 115 between the plates 111 and 113 not only defines the spacing between the guide pkltes to be a~mplementary to the thickness of the profile portion of the closure 100, but also serves as a guide for the free edge of the pull flange 106 so that between the guide element 115 and the shoulder 109 and the confronting surfaces of the guide plates 111 and 113, the profite portion of the fastener 100 is substantially accurately guided for longitud inal travel relative to apparatus mechanism of any preferred form (not shown) for bringing the webs 101 into assembly with the flanges 104 and 105 and supplying the adhesive 103 for securing the web and fastener parts together. By varying the width of the spacing gauge and guide element 115, any thickness of profile section can be accommodated for the closure assembly 100, and by adjusting the element 115 relative to the shoulder 109 any preferred width of the profile portion of the closure 100 can be accommodated. To enable adjustment, the plates 111 and 113 and the element 115 are secured together by means such as one or more bolts 116 extending through the elements 115 and through adjustment slots li7 inthe plates 111 and 113. The bolt means Z0 116 not only secure the element 115 fixedly in place, but also secure the plate 113 fixedly in relation to the plate 111 and the support 1 12.
So-called hot melt adhesives are especially useful for adhesive bonding of the fastener strips to the webs according to the present invention. Such adhesives are available from many sources. A clear transparent adhesive has been found especially -~7-10~'~825 satisfactory not only becnuse of its lack of disfiguring coloration where either or both the web and the fastener nQy be transparent.
A thermofusible synthetic resin adhesive having a desirable viscosity at utilization temperature of 150 to 190C permits advan-tageous closely controlled thin layer nozzle application without dripping or running, instantaneous adhesive bond. Rapid setting of the adhesive to completion in 3 to 5 seconds is desirable.
Such adhesive also meet the qualification of adequate tackiness to resist slippage from the point of interface contact of the parts to complete permanent bonding set of the adhesive. After setting, the adhesive must retain the bond perrnanently without deterio-ration, ~nd remain pliable in the bond consistent with the flexibility of the fastener and web assembly.
Of course, where a pressure sensitive adhesive is applied to the back of the fastener strip, accordingto the modifi-cation of Fig. 10, and wherein the adhesive must remain tacky at least while attached to the protective, strippable backing web, a pressure sensitive adhesive of any preferred known type such as applied to pressure sensitive tapes may be used.
~0

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for separable interlocking with a complementary second flexible separable fastener profile, comprising moving the web and the fastener strip substantially continuously at the same high speed convergently toward one another and joining the interface surface areas of the web and fastener strip, effecting guidance of the interlocking profile and thereby of the moving fastener strip in a predetermined path into said joining with the moving web, just prior to the joining of the high speed convergently moving web and fastener strip substantially continuously applying a thin sub-stantially uniform layer of adhesive to a substantial width of at least one of said interface surface areas, and comprising discharging the thin adhesive layer substantially in the direction of movement of the web and strip directly onto said one surface area from a nozzle having a narrow slit-like elongated orifice disposed close to said joining and extending with its length transversely parallel to said interface surface areas, and pressing said web and fastener strip and adhesive layer together at said joining and effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in said high speed movement.

2. A method according to claim 1, comprising applying said adhesive layer to the interface surface area of the fastener strip upstream from the convergent meeting location of said interface areas during said substantially continously high speed movement.

3. A method according to claim 1, comprising applying as the adhesive a thin layer of a hot melt quick setting adhesive.

4. A method according to claim 1, comprising applying as the adhesive layer a pressure sensitive adhesive.

5. A method according to claim 1, 2 or 3, comprising shaping the web into bag form with the fastener strip providing closure means for the bag.

6. A method according to claim 1, comprising convergently joining with the web at said substantially continous high speed a plurality of spaced parallel complementary profiled fastener strips, applying to the interfaces of the web and each of the strips a thin layer of bonding adhesive, permanently securing the interfaces of the strips to the inter-face of the web by means of the adhesive, folding the web longitudinally intermediate the fastener strips, bringing the profiles of the fastener strips into interlocking relation, and forming the folded web into bag sections for which the fastener strips provide a separable closure.

7. A method according to claim 1, comprising joining a second fastener strip having said second complementary profile to the web concurrently with and parallel to and in the same manner as said first fastener strip and in a location on the web so that by folding the web along a longitudinal line intermediate the strips can be interlocked to provide a separable closure.

8. A method according to claim 1, comprising interlocking the profile of said first fastener strip and a complementary second profile on a second flexible separable fastener strip, moving the interlocked fast-ener strips together and converging the interface surfaces of the strips with web interface surfaces, supplying adhesive layers to secure the inter-faces of the strips to the web interface area, and fastening the strip inter-faces to the web interface areas by means of said adhesive layers.

9. A method according to claim 1, wherein said first fastener strip has complementary integral profiles in spaced parallel relation, and guiding the fastener strip into convergence with the web by utilizing the profiles as guide means.

10. A method according to claim 1, comprising guiding said first fastener strip into convergence with the web utilizing its profile as guide means.

11. A method according to claim 1, wherein said first fastener strip has a second profile parallel to its first mentioned profile, interlocking with said profiles complementary respective profiles on additonal separable flexible fastener strips, and applying adhesive layers between the interface surfaces of the additional strips and the interface surface areas of web material and thereby joining the additional strips to the web material.

12. A method according to claim 1, wherein said first fastener strip has a second profile parallel to its first mentioned profile, interlocking with the profiles of the first strip comple-mentary profiles on a second flexible separable fastener strip, and adhesively attaching said second fastener strip to web material moving concurrently with the first mentioned strip and web.

13. A method according to claim 1, comprising controlling the adhesive layer so that it remains in a width less than the width of the interface surface of the strip and spaced from the longitudinal edges of the strip.

14. A method according to claim 1, comprising applying said adhesive layer to underlie said profile of the fastener strip whereby the profile area of the strip will be thoroughly secured to the web by the adhesive.

15. A method according to claim 1, which comprises applying said adhesive layer as hot thermofusible synthetic resin at a temperature of from 150°to 190°C in a layer no greater than 1/10 mm thick at a speed up to 300 meters per minute, so that it sets within 3 to 5 seconds.

16. A method according to claim 1 comprising rolling the web and attached fastener into a supply roll for subsequent use in making articles such as bags.

17. Apparatus for attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for interlocking with a complementary second flexible separable fastener profile: means for moving the web and the fastener strip at high speed and substantially continuously convergently toward one another to join the interface surface areas of the web and fastener strip; a nozzle having a narrow slit-like orifice disposed close to the joining of said interface surface areas and extending with its length transversely parallel to said areas for substantially continuously applying a thin layer of adhesive to at least one of said interface surface areas; and means for effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in said high speed movement.

18. Apparatus according to claim 17, wherein said means for applying said adhesive layer to the interface of the fastener strip are located upstream from the convergent meeting location of said interfaces during said substantially continuous high speed movement.

19, Apparatus according to claim 17, comprising means for supplying a hot melt quick setting adhesive to said means for applying the adhesive.

20. Apparatus according to claim 17, comprising means for supplying a pressure sensitive adhesive to said means for applying the adhesive layer.

21. Apparatus according to claim 17, comprising means for shaping the web into bag form with the fastener strip providing closure means for the bag.

22. Apparatus according to claim 17, wherein said means for moving the web at said substantially continuous high speed accommodates a plurality of spaced parallel complementary profiled fastener strips, said means for applying adhesive being adapted to apply the adhesive to the interface surface areas of the web and each of the strips, said means for attachment effecting permanent securement of the interface areas of the plurality of strips to the interface areas of the web by means of the adhesive, and means for folding the web longitudinally.

23. Apparatus according to claim 17, wherein said means for moving and said means for effecting attachment accom-modate a second complementary profiled prefabricated fastener strip for attachment to the web concurrently with an parallel to and in the same manner as said first strip and in a location on the web so that by folding the web along a longitudinal line inter-mediate the strips the profiles of the strips can be interlocked to provide a separable closure.

24. Apparatus according to claim 17, wherein said means for moving accommodates a complementary profile of a second prefabricated flexible separable fastener strip interlocked with the profile of said first fastener strip and is operable to move the interlocked fastener strips together and to effect con-vergence of the interface surface areas of the strips with web interface surface areas, said applying means applying adhesive layers to secure the interface areas of both of the strips to the web interface areas, and said attachment effecting means effect-ing attachment of both of the strip interface areas to the web interface areas by means of said adhesive layers.

25. Apparatus according to claim 17, comprising means for guiding the fastener strip in movement into said con-vergence with the web utilizing said profile as guide means.

26. Apparatus according to claim 25, wherein said guiding means include means for utilizing a plurality of fastener strip profiles as guide means.

27. Apparatus according to claim 17, wherein said means for moving said fastener strip accommodates a second profile parallel to said first mentioned profile and said profiles being interlocked with complementary respective profiles on additional prefabricated separable flexible fastener strips, and said applying means also applying adhesive layers between the interface surface areas of the additional strips and the interface surface areas of web material and thereby joining the additional strips to the web material.

28. Apparatus according to claim 17, wherein said applying means includes means for controlling the adhesive layer to remain in a width less than the width of the interface surface area of the strip and spaced from the longitudinal edges of the strip,

29. Apparatus according to claim 17, wherein said applying means applies said adhesive layer to underlie the pro-file of the fastener strip, whereby the profile area of the strip interface will be most thoroughly secured to the web by the adhesive.

30. Apparatus according to claim 17, wherein said applying means are adapted to apply said adhesive layer as hot thermofusible synthetic resin at a temperature of from 150 to 190° C. in a layer no greater than 1/10 mm thick at a speed up to 300 meters per minute, that is adapted to set in 3 to 5 seconds after being applied.

31. Apparatus according to claim 17, comprising means for rolling the web and attached fastener into a supply roll for subsequent use in making articles such as bags.

32. Apparatus according to claim 17, comprising means having surfaces cooperating with the fastener strip and the interlocking profile for guiding the moving fastener strip.

33. Apparatus according to claim 32, including means for effecting relative adjustment of said surfaces to accommodate variables in fastener strip and profile dimensions.

34. Apparatus according to claim 17, 18 or 22, wherein said applying means are adapted to supply said adhesive layer as hot thermo-fusible synthetic resin at a temperature of from 150 to 190°C.

35. Apparatus according to claim 17, 18 or 25, wherein said applying means are adapted to apply said adhesive layer as hot thermofusible synthetic resin in a layer no greater than 1/10 mm thick.

36. Apparatus according to claim 17, 18 or 28, wherein said applying means are adapted to apply said adhesive layer as hot thermofusible synthetic resin at a speed up to 300 meters per minute.

37. Apparatus according to claim 17, 18 or 31, wherein said applying means are adapted to apply said adhesive layer as hot thermofusible synthetic resin that is adapted to set in 3 to 5 seconds after being applied.

38. A method of attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for separable interlocking with a complementary second flexible separable fastener profile, comprising supplying said fastener strip made from a desired plastic material, supplying said web made of a material which is not fusibly attachable to said fastener strip, moving the web and the fastener strip substantially continuously at the same high speed convergently toward one another and joining the interface surface areas of the web and fastener strip, effecting guidance of the moving fastener strip in a predeter-mined path into said joining with the moving web, just prior to the joining of the high speed convergently moving web and fastener strip substantially continuously applying a thin sub-stantially uniform layer of adhesive to a substantial width of at least one of said interface surface areas, and comprising discharging the thin adhesive layer substantially in the direction of movement of the web and strip directly onto said one surface from a nozzle having a narrow slit-like orifice parallel to and extending transversely across said interface surface areas;
and pressing said web and fastener strip and adhesive layer together at said joining and effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in said high speed movement.

39. A method according to claim 1 or 38, comprising supplying said fastener strip made from polyethylene, and supplying said web made from polypropylene.

40. A method according to claim 1 or 38, comprising supplying said web made from paper.

41. A method of attaching to a prefabricated flexible web a first prefabricated flexible separable fastener strip having an interlocking profile adapted for separable inter-locking with a complementary second flexible separable fastener profile, comprising moving the web and the fastener strip sub-stantially continuously at the same high speed convergently toward one another and joining the interface surface areas of the web and fastener strip, effecting guidance of the moving fastener strip in a predetermined path into said joining with the moving web, just prior to the joining of the con-vergently moving web and fastener strip substantially con-tinuously applying a thin substantially uniform layer of adhesive to at least one of said interface surface areas by discharging the adhesive layer substantially in the direction of movement of the web and fastener strip and directly onto said one surface from a nozzle having a narrow elongate slit-like orifice located close to said joining and with its length extending parallel to the transverse dimensions of the fastener strip and web and said length being less than the width of the fastener strip, substantially accurately locating the nozzle orifice and controlling the flow of adhesive therefrom so that the width of the adhesive layer is narrower than the width of said fastener strip and sufficiently spaced inwardly from the longitudinal edges of the fastener strip so that even though there may be some lateral migration of the adhesive layer before it is set none of the adhesive will escape beyond said longitudinal edges of the fastener strip;
and pressing said web and fastener strip and adhesive layer together at said joining and effecting attachment of the interface surface areas to one another by means of the adhesive layer while the web and fastener strip continue jointly in said high speed movement.

42. A method according to claim 41, comprising effecting said joining and said pressing and said attachment by squeezing the fastener strip and the web together by and between pressure rollers.

43. A method according to claim 42, comprising guiding the fastener strip to said joining by running said interlocking profile through guide grooves in one of said rollers.

44. A method according to claim 41, comprising effecting said joining and attachment of the fastener strip and web by effecting travel of the web along one member and by effecting travel of the fastener strip along a surface on a stationary member inclined toward said joining.

45. A method according to claim 44, comprising sub-stantially accurately guiding said fastener strip by guiding said interlocking profile in a groove in said inclined surface of said stationary member.

46. A method according to claim 1, 38 or 41, including applying said adhesive layer to include that portion of the interface surface area of the fastener strip along the back of the interlocking profile.

47. A method according to claim 1 or 41, comprising supplying said web made of a material which is not fusibly attachable to said fastener strip but which is permanently bondable to said fastener strip by said applying of a thin substantially uniform layer of adhesive.

48. A method according to claim 1 or 41, comprising supplying said web of a plastic material which is not fusible with plastic material of the fastener strip.

49. A method according to claim 41, comprising supplying said fastener strip made from polyethylene, and supplying said web made from polypropylene.

50. A method according to claim 1, 38, or 41, comprising applying the thin substantially uniform layer of adhesive to the interface area of said fastener strip.

51. A method according to claim 1, 38 or 41, which comprises applying said adhesive layer as hot melt thermo-fusible synthetic resin at a temperature of from 150°to 190°C.

52. A method according to claim 1, 38 or 41, which comprises applying said adhesive layer as hot thermofusible synthetic resin in a layer no greater than 1/10 mm thick.

53. A method according to claim 1, 38 or 41, which comprises applying said adhesive layer as hot thermofusible synthetic resin at a speed up to 300 m per minute.

54. A method according to claim 1, 38 or 41, which comprises applying said adhesive layer as hot thermofusible synthetic resin adapted to set in three to five seconds.