EP0431144B1 - Process and device for making a product consisting of a base having an adhesive with long-term effect and a protection band attached - Google Patents

Abstract

The process relates to the production of a product consisting of a substrate to which an adhesive with long-term effect and a protective band are attached to permit use of the adhesive to be deferred. The process is characterized by the use of a substrate whose surface to which the adhesive is attached may present irregularities. The adhesive is heated to a temperature at which is becomes paste-like and almost liquid, and is brought to an opening situated above a plane surface on which the substrate has been placed. The adhesive is then caused to flow simultaneously with a relative movement between the substrate and the opening. This results in the adhesive being deposited on the substrate as a strand that is preferably continuous. The temperature of the adhesive is then lowered in order to increase its viscosity until it becomes paste-like to the point of turning solid. Pressure is thereafter applied to the paste, like adhesive, preferably with the imposition of a protective strip, in order to cause spreading of and to cover the strand along its full length. Finally, the resultant product may be cut to produce a substrate having an adhesive strip thereon and a detachable protection band covering the adhesive strip.

Description

Modern adhesives have reached an excellent degree of efficiency and the trend is towards their generalization in place of other means of assembly.

In the field of cardboard articles, and especially for packaging for example, it is often more advantageous to join two pieces with glue rather than with staples or connecting lugs.

The general problem of fixing with an adhesive can subsist in two families: immediate bonding and deferred bonding.

The present invention essentially relates to this second family which groups all the cases where an adhesive must first be deposited on a part, or "support", then the support coated with adhesive, which should only be used subsequently , sometimes very long after, to bring together the first support to a so-called "destination" surface, after all kinds of events have occurred: printing, shaping, storage, packaging, transport, delivery, new storage, retail destocking, handling various, etc.

The technique of immediate bonding has become relatively simple because, ultimately, it is now reduced to choosing a type of adhesive and, if necessary, adapting the adhesive chosen to the problem posed, adjusting its composition and / or setting time, because the two parts are fixed at the same time and there is no longer any need to distinguish an adhesive support and a destination surface.

• dépôt d'adhésif sur un support donné,
• résistance de l'adhésif au vieillissement et aux sollicitations physico-mécaniques,
• efficacité du même adhésif sur la surface de destination, même longtemps après le dépôt initial sur le support.

On the other hand, deferred bonding is infinitely more complex since it is necessary to satisfy very diverse requirements, arising from the existence of three distinct situations instead of just one:

• deposit of adhesive on a given support,
• resistance of the adhesive to aging and to physical-mechanical stresses,
• effectiveness of the same adhesive on the destination surface, even long after the initial deposit on the support.

Here, it is therefore necessary to distinguish two very different operations although they always involve the same adhesive: adhesion to the support then adhesion to the destination surface, the assembly having to ensure the effective joining of two pieces: the support and the surface of destination.

The solutions which currently exist do not give complete satisfaction in all fields of application.

For example, it is quite easy to deposit so-called "self-adhesive" adhesives on supports made of materials having a regular surface and / or of excellent flatness.

This is the case of the paper used for the manufacture of envelopes, in particular, because during the deposition of the adhesive the paper is placed on a rigid and flat support, such as a steel plate, so that its flexibility results in adaptability to this support, the characteristics of which it acquires. Finally, if the paper is correctly guided and maintained, it behaves as if it were itself rigid and hard.

This is also the case for materials naturally offering these characteristics: glass, metal, synthetic materials and compact cartons that are properly surfaced.

Assuming that the adhesive is firmly associated with the support, subsequent bonding to the destination surface is not guaranteed, since the qualities of the adhesive must still be preserved over time and it must find a surface. correct destination.

Here again, the case of paper is relatively simple because being both flexible and thin, the destination surface will be perfectly adapted to the adhesive.

In these favorable cases, the problem to be resolved is therefore to mask the adhesive so that it does not accidentally adhere to other objects and to protect it against dust retention as well as against aging (drying, oxidation, etc. .). The solution adopted consists in placing a tape associated with silicones on the adhesive, which adheres very little to the adhesive.

On the other hand, "self-adhesive" adhesives are ill-suited to materials which are not either regular and rigid or, on the contrary, very flexible so that the destination surface matches the support.

A typical example of a poorly suited material is corrugated cardboard and this is the one used here to explain the invention, although it has many other applications for various materials.

A sheet of corrugated cardboard essentially has a corrugated face and a so-called "flat" face, although by observing the latter with care one discerns, even with the naked eye, fairly well marked depressions.

In practice, the most frequently encountered sheet of corrugated cardboard has two flat faces placed on either side of a core having corrugations, or grooves.

Naturally, depending on the specific resistance desired, it is also possible to give a sheet of corrugated cardboard a more complex structure: two corrugated cores and three flat faces, two outer and one inner separating the two corrugated cores, for example.

To simplify the description, we will be satisfied here with the case where the sheet of corrugated cardboard has a corrugated core and two flat faces.

To apply self-adhesive adhesive to such a sheet, a ribbon of thin material is used, impermeable to the adhesive and slightly sensitive to the action of said adhesive. One of the two sides of this tape is coated with adhesive, with the possible use of a treatment allowing the adhesive to "hang" more on one side than on the other. This adhesive-tape set is stored on a reel.

When applying the adhesive to the sheet of corrugated cardboard, the coated tape is unwound, an easy operation since the spiral winding has the effect that the adhesive is against the less adhesive side of the tape and there adheres very little.

The tape is applied by its coated side and the adhesive meets a material conducive to its adhesion.

The sheet-adhesive-tape assembly is then stored, transported, distributed, etc. until the actual use of the adhesive which is deferred in time compared to when the adhesive was applied to the tape.

Generally, the sheet of corrugated cardboard is a constituent part of a blank intended to form a container.

It is therefore when the container is closed that the adhesive is needed to join the "support" part and the "destination surface" part. To do this, one end of the tape is lifted which detaches more easily from the adhesive than it detaches from the cardboard sheet. Also, can we easily remove the protective tape to release all the adhesive that remains attached to the cardboard sheet ("support") on which it was applied.

On the exposed side by removal of the tape, the adhesive must have retained its adhesion in order to allow by simple contact to fix the cardboard sheet (support) on another part also made of cardboard (destination surface). By thus applying the part carrying the adhesive on a part which does not have one, the two parts are bonded.

Such a coated and treated tape is quite expensive, both for its manufacture and for its installation, so that it is a solution generally discarded when the final product, incorporating the sheet of self-adhesive corrugated cardboard. , must be inexpensive.

Indeed, in addition to the actual constitution of the coated ribbon, the installation of this ribbon supposes that the sheet of corrugated cardboard offers a very regular surface, that is to say devoid of deformation.

However, during the manufacture of a sheet of corrugated cardboard with thin papers, the outer sheets which constitute the so-called "flat" faces of the sheet are applied and bonded directly to the corrugated core and despite all the precautions that one can take (sheet tension, guidance, control of the laying speed, quality of the adhesive, etc.) there are depressions of the outer sheets between the tops of two neighboring undulations.

These depressions are sometimes invisible to the naked eye and are barely sensitive to the touch.

This characteristic of this type of corrugated cardboard is well known to those skilled in the art since the determination of the thickness of a sheet of corrugated cardboard cannot be done with a simple device: it is necessary that the parts in contact with the two faces of the sheet whose thickness is to be measured have a relatively large area in order to compensate for the irregularities which are discussed here.

For example, the French standard NF Q 03-030 specifies that the parts of the device ("keys") in contact with the sheet must have ten square centimeters (10 cm2) each.

In "LE COLLAGE INDUSTRIEL" by Philippe Cognard and Françoise Pardos, Editions l'Usine Nouvelle, Paris, page 12, it says:

"ACTUAL CONTACT SURFACE

The contact between the two surfaces of two solids is made only in a few points, if one places oneself from the microscopic point of view. If we assume the case of a liquid wetting a solid, there will be microscopic air bubbles which will prevent contact. So in these two cases, the real contact is lower than the proposed contact and the real resistance will therefore be much lower than the maximum theoretical resistance.

SURFACE FAULTS

For an equal contact surface, an actual surface will provide a value of the adhesion force lower than that which an ideal regular surface would provide. This results from the existence of numerous defects in real surfaces ".

To make a sheet of corrugated cardboard self-adhesive, it is above all necessary that it has a surface as regular as possible and that the tape used is itself of very good quality, these factors being incompatible with a low cost price. .

However, even with sheets of corrugated cardboard made with thick papers, one does not always achieve a satisfactory result.

Up to now, better results have been obtained by using tapes comprising a central strip coated with an adhesive on both sides and made of a material on which the adhesive hangs vigorously. On one of the coated faces, a protective tape is weakly sensitive to the action of the adhesive and therefore easily removable. It is generally a paper or synthetic tape associated with silicones.

The entire central strip, the two layers of adhesive and the protective tape is wound up to be stored in reels.

To make an object (a box for example) self-adhesive, we unwind a certain length of tape without or with central strip, we apply the coated side to the object ("support") and we cut the unwound segment to the length which corresponds to the dimension of the object already shaped.

When the tape is of the type comprising a central strip, the latter is thus fixed once and for all on the support and the adhesive applied will never be used again or even unmasked.

The support-central strip-adhesive-protective tape assembly is then stored, transported, distributed until the user has to use the adhesive, for example to close an envelope, by sticking a flap (support) on the envelope itself (destination surface) or to close a container of any other type.

For this, the user must remove the protective tape in order to unmask the adhesive located outside the central strip. Then, he applies the sheet (support) on another (destination surface) by applying the visible adhesive.

Such an expensive and very elaborate tape improves the results and compensates by its high qualities the mediocrity of the flatness of the sheets of corrugated cardboard.

However, better results require the use of very thick papers to constitute the corrugated cardboard, so that the fixing of the support to the destination surface by the adhesive is correct.

It is then necessary to give up the best designed products from the cost point of view, which is a shame for consumers because either they have high-performance but very expensive products or they have cheap but poor products.

• US-A-4 102 301 qui concerne exclusivement un procédé de revêtement et expose une solution pour fabriquer, à partir de ce prodédé, soit des films à effet barrière pour le conditionnement de salaisonneries, jambons, etc., soit des rubans adhésifs pour la papeterie.

To situate the state of the art, the following documents can be cited:

• US-A-4,102,301 which relates exclusively to a coating process and sets out a solution for manufacturing, from this product, either barrier effect films for the packaging of salted meats, hams, etc., or adhesive tapes for the stationery store.

The process consists in covering the entire surface of the support to be coated and, to this end, several ribbons of the coating product are first placed, then by means of a roller common to all the ribbons, they are spread so that 'they meet and form a complete covering.

• FR-A-2 331 386 qui décrit une machine automatique pour déposer des pastilles adhésives sur des carreaux de faïence et pour écraser celles-ci au moyen d'un plateau de presse, une feuille faiblement adhésive étant intercalée entre les pastilles et le plateau de presse.

The support to be coated has no irregularities, quite the contrary, since it is an extruded sheath of synthetic material laid flat.

• FR-A-2 331 386 which describes an automatic machine for depositing adhesive tablets on earthenware tiles and for crushing them by means of a press plate, a weakly adhesive sheet being interposed between the tablets and the plate hurry.

The solution described does not allude either to the existence of irregularities of the support, or to the fibrous nature of this support, or to the use of a flowing adhesive, or to the creation of a continuous bead, or to lamination. of this cord for its function of equalizing the irregularities of the support.

The present invention overcomes all the drawbacks mentioned above and makes it possible to obtain supports: sheets or panels of any material, provided with a long-acting adhesive for a deferred use of this adhesive and, what, whatever the quality of supports, regularity or irregularity of the surfaces present, the fineness or the thickness of the materials used.

To this end, the subject of the invention is a method for manufacturing a product consisting of a support, in particular a support made of fibrous material of which at least one face has irregularities, and on which there is a long-acting adhesive and a tape. of protection for a deferred use of said adhesive, of the type comprising the stages according to which the adhesive is deposited, then it is subjected to a pressure, characterized in that the adhesive is heated to a temperature to which it is pasty at the limit of the liquid state, then that it is led to at least one orifice opening above a plane on which the support is placed, then that one causes its flow at the same time that a relative movement is caused between the support and the orifice so that the adhesive is deposited on the support either according to at least one thick bead, in particular continuous, or according to a series of distinct deposits, that the adh temperature sif deposited to increase its viscosity until it is pasty at the limit of solid state, then that the protective tape is applied to the adhesive bead (s) then that one exerts on the tape protection a pressure intended to cause rolling, as well as the crushing of the bead or the lateral spreading of the bead which may result from rolling, over its entire length so that after having exerted this pressure, the bead occupies only a fraction of the width of the support, then optionally at least one subsequent cutting of the product consisting of a support, an adhesive strip and a protective tape.

• le produit est destiné à être façonné après mise en place de l'adhésif et du ruban de protection, afin de constituer un article fini, prêt à l'emploi par usage de l'adhésif découvert par retrait du ruban de protection;
• le support étant fait en un matériau relativement rigide, on le soumet à un effort de pression localisé dans la zone où l'on doit provoquer l'écoulement de l'adhésif, afin d'obtenir un amolissement du support qui, dans cette zone, devient ainsi plus souple qu'à l'origine;
• l'effort de pression intéresse une bande dont la largeur est supérieure à celle de l'adhésif après application;
• l'effort de pression est calibré pour être supérieur à la résistance élastique du matériau formant le support;
• la matériau du support présentant une structure interne alvéolée, comme c'est le cas du carton ondulé dont les cannelures créent des alvéoles longitudinaux, l'effort de pression est calibré pour être capable de briser les parois des alvéoles formant entretoises entre deux faces opposées du support, mais insuffisant pour supprimer toute élasticité perpendiculaire auxdites faces;
• le procédé étant mis en oeuvre dans un local à température ambiante, on abaisse la température de l'adhésif par simple absence de chauffage et en provoquant le mouvement relatif à une vitesse telle que le temps qui s'écoule entre le dépôt de l'adhésif et son application par pression corresponde à l'abaissement de température voulu;
• le procédé étant mis en oeuvre dans un local à température ambiante, et le mouvement relatif ayant une vitesse donnée, on exerce une pression sur l'adhésif à une distance de l'orifice d'écoulement telle que le temps qui s'écoule entre le dépôt de l'adhésif et son application par pression corresponde à l'abaissement de température voulu;
• après dépôt, on soumet le cordon d'adhésif à des moyens de refroidissemnet positif, tels qu'un flux d'air froid;
• le support étant en carton ou matériau analogue, on pose sur le cordon d'adhésif préalablement déposé sur le support un ruban en matériau mince, imperméable à l'adhésif et faibement sensible à l'action dudit adhésif et, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban;
• le support étant en carton ou matériau analogue enroulé selon une grande longueur sous forme de bobine, on dépose au moins un cordon d'adhésif longitudinal en même temps que l'on déroule le support, on pose sur le cordon un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban et l'on enroule cet ensemble selon une bobine en vue de son stockage;
• le support étant en carton ou matériau analogue enroulé selon une grande longueur sous forme de bobine, on dépose au moins un cordon d'adhésif longitudinal en même temps que l'on déroule le support, on pose sur le cordon un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban, on enroule cet ensemble selon une bobine en vue de son stockage, puis, avant usage de l'adhésif, on découpe le support en panneaux destinés à constituer des flans, notamment pour l'obtention de contenants;
• le support étant un panneau en carton ou matériau analogue, on dépose au moins un cordon d'adhésif sur ledit panneau d'un premier bord que celui-ci présente à un second bord opposé au précédent, on pose sur le cordon un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban puis, éventuellement, on élimine des marges imparfaites;
• le support étant un panneau en carton ou matériau analogue, on traite plusieurs panneaux amenés les uns après les autres en laissant subsister entre eux un espace, on dépose au moins un cordon d'adhésif sur chaque panneau d'un premier bord qu'ils présentent à un second bord opposé au précédent, on pose sur le cordon un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, ruban qui est continu et qui s'étend d'un panneau à un autre par-dessus l'espace qui les sépare et, afin d'appliquer le cordon d'adhésif sur chaque panneau, on exerce une pression sur le ruban à l'aplomb de chaque panneau, puis on procède à une découpe du ruban entre les panneaux;
• la découpe est effectuée contre les deux bords opposés de chaque panneau;
• la découpe est effectuée entre les deux bords en regard de deux panneaux voisins;
• la découpe laisse subsister au moins un segment de ruban au-delà d'au moins l'un des bords de chaque panneau;
• le support étant en carton ou matériau analogue, on pose sur le cordon d'adhésif déposé un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban, la quantité d'adhésif déposé et la valeur de la pression exercée sur le ruban étant coordonnées de telle sorte qu'après application du cordon, la largeur que l'adhésif occupe sur le support soit au plus égale à celle dudit ruban;
• le suppport étant en carton ou matériau analogue, on pose sur le cordon d'adhésif déposé un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif et l'on provoque l'application du cordon seulement quand la température jusqu'à laquelle il s'est abaissé après dépôt sur le support a suffisamment augmenté sa viscosité pour que son degré d'adhérence au ruban en matériau mince soit nettement inférieur au degré d'adhérence qu'il a avec le support;
• le support étant en carton ou matériau analogue, on provoque l'écoulement de l'adhésif par un orifice qui a une section et une orientation telles que le cordon d'adhésif déposé par écoulement ait une section sensiblement circulaire, on pose le ruban en matériau mince à une certaine distance dudit orifice en coordonnant cette distance, la température à laquelle l'adhésif est déposé sur le support et la vitesse du déplacement relatif, pour que le cordon d'adhésif s'affaisse un peu latéralement, alors on pose sur le cordon d'adhésif un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif et afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban;
• le support étant en carton ou matériau analogue, on dépose au moins un cordon d'adhésif, on pose sur celui-ci un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban, on dépose et lamine au moins un cordon d'adhésif en quantité suffisante pour que le cordon, après son application, comble toutes lesdites irrégularités et offre en outre au ruban en matériau mince une surface plane et continue;
• le support étant en carton ou matériau analogue déformable, on aplanit le support au moins selon la zone devant recevoir ledit adhésif, on dépose au moins un cordon d'adhésif, on pose sur celui-ci un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif et afin d'appliquer le cordon d'adhésif sur le support, on exerce une pression sur le ruban;
• le support étant en carton ou matériau analogue déformable, on réalise un creux régulier sur toute la zone devant recevoir ledit adhésif, on dépose au moins un cordon d'adhésif dans ledit creux, on pose sur ledit cordon un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, afin d'appliquer le cordon d'adhésif dans le creux du support on exerce une pression sur le ruban, la profondeur dudit creux étant sensiblement égale à l'épaisseur totale de l'adhésif appliqué et du ruban en matériau mince;
• on chauffe l'adhésif, on le fait circuler dans un conduit en circuit fermé et l'on provoque ledit écoulement en prélevant une fraction d'adhésif circulant dans le conduit en circuit fermé;
• on chauffe l'adhésif, on le fait circuler dans un conduit en circuit fermé, on maintient l'adhésif qui circule dans le conduit en circuit fermé sensiblement à la température qu'il doit avoir pour son écoulement et l'on provoque ledit écoulement en prélevant une fraction d'adhésif circulant dans le conduit en circuit fermé;
• on chauffe l'adhésif, on le fait circuler dans un conduit en circuit fermé, on prélève une fraction d'adhésif circulant dans le conduit en circuit fermé, on augmente la température de la fraction d'adhésif prélevée et l'on provoque ensuite l'écoulement de ladite fraction.

According to other characteristics of this process:

• the product is intended to be shaped after placing the adhesive and the protective tape, in order to constitute a finished article, ready for use by using the adhesive discovered by removing the protective tape;
• the support being made of a relatively rigid material, it is subjected to a pressure force located in the area where the adhesive must flow, in order to obtain a softening of the support which, in this area, thus becomes more flexible than originally;
• the pressure force concerns a strip whose width is greater than that of the adhesive after application;
• the pressure force is calibrated to be greater than the elastic resistance of the material forming the support;
• the support material having an internal honeycomb structure, as is the case of corrugated cardboard whose grooves create longitudinal cells, the pressure force is calibrated to be able to break the walls of the cells forming spacers between two opposite faces of the support, but insufficient to remove any elasticity perpendicular to said faces;
• the process being implemented in a room at room temperature, the temperature of the adhesive is lowered by simple absence of heating and by causing the relative movement at a speed such that the time which elapses between the deposition of the adhesive and its application by pressure corresponds to the desired temperature reduction;
• the method being implemented in a room at room temperature, and the relative movement having a given speed, a pressure is exerted on the adhesive at a distance from the flow orifice such that the time which elapses between the deposition of the adhesive and its application by pressure corresponds to the desired temperature reduction;
• after deposition, the adhesive bead is subjected to positive cooling means, such as a flow of cold air;
• the support being made of cardboard or similar material, a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, is placed on the adhesive bead previously deposited on the support and, in order to apply the bead adhesive on the support, pressure is applied to the tape;
• the support being made of cardboard or similar material wound up over a great length in the form of a coil, at least one bead of longitudinal adhesive is deposited at the same time as the support is unrolled, a ribbon of thin material is placed on the bead, impermeable to the adhesive and weakly sensitive to the action of said adhesive, in order to apply the bead of adhesive to the support, pressure is exerted on the tape and this assembly is wound up according to a spool for storage ;
• the support being made of cardboard or similar material wound up over a great length in the form of a coil, at least one bead of longitudinal adhesive is deposited at the same time as the support is unrolled, a ribbon of thin material is placed on the bead, impermeable to the adhesive and weakly sensitive to the action of the said adhesive, in order to apply the bead of adhesive to the support, pressure is exerted on the tape, this assembly is wound up on a spool for storage, then , before using the adhesive, the support is cut into panels intended to constitute blanks, in particular for obtaining containers;
• the support being a cardboard or similar material panel, at least one bead of adhesive is deposited on said panel with a first edge which the latter has at a second edge opposite to the previous one, a ribbon of material is placed on the cord thin, impermeable to the adhesive and weakly sensitive to the action of said adhesive, in order to apply the bead of adhesive to the support, pressure is exerted on the tape then, optionally, imperfect margins are eliminated;
• the support being a cardboard or similar material panel, we treat several panels brought one after the other leaving a space between them, we deposit at least one bead of adhesive on each panel with a first edge that they present at a second edge opposite the previous one, a ribbon of thin material is applied to the cord, impermeable to the adhesive and weakly sensitive to the action of said adhesive, a ribbon which is continuous and which extends from one panel to another over the space which separates them and, in order to apply the adhesive bead on each panel, a pressure is exerted on the tape directly above each panel, then a ribbon is cut between the panels ;
• the cutting is carried out against the two opposite edges of each panel;
• the cut is made between the two edges opposite two neighboring panels;
• the cut leaves at least one segment of ribbon remaining beyond at least one of the edges of each panel;
• the support being made of cardboard or similar material, a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, is placed on the adhesive bead in order to apply the adhesive bead to the support, pressure is exerted on the tape, the quantity of adhesive deposited and the value of the pressure exerted on the tape being coordinated so that after application of the bead, the width that the adhesive occupies on the support is at more equal to that of said ribbon;
• the support being made of cardboard or similar material, a strip of thin material is applied to the bead of adhesive deposited, impermeable to the adhesive and slightly sensitive to the action of said adhesive, and the bead is only applied when the temperature to which it has dropped after being deposited on the support has sufficiently increased its viscosity so that its degree of adhesion to the ribbon of thin material is significantly lower than the degree of adhesion that it has with the support;
• the support being made of cardboard or similar material, the adhesive is caused to flow through an orifice which has a section and an orientation such that the adhesive bead deposited by flow has a substantially circular section, the ribbon of material is placed thin at a certain distance from said orifice by coordinating this distance, the temperature at which the adhesive is deposited on the support and the speed of the relative displacement, so that the bead of adhesive collapses a little laterally, then it is placed on the bead of adhesive a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive and in order to apply the bead of adhesive to the support, pressure is exerted on the ribbon;
• the support being made of cardboard or similar material, at least one bead of adhesive is deposited, a ribbon of thin material is applied thereto, impermeable to the adhesive and slightly sensitive to the action of said adhesive, in order to apply the adhesive bead on the support, a pressure is exerted on the tape, at least one bead of adhesive is deposited and laminated in sufficient quantity so that the bead, after its application, fills all said irregularities and also offers the tape in thin material, a flat and continuous surface;
• the support being made of cardboard or similar deformable material, the support is flattened at least according to the zone to receive said adhesive, at least one bead of adhesive is deposited, a ribbon of thin material impermeable to it is placed on it adhesive and weakly sensitive to the action of said adhesive and in order to apply the bead of adhesive to the support, pressure is exerted on the tape;
• the support being made of cardboard or similar deformable material, a regular recess is produced over the entire area which is to receive said adhesive, at least one bead of adhesive is deposited in said recess, a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, in order to apply the bead of adhesive in the hollow of the support, pressure is exerted on the tape, the depth of said hollow being substantially equal to the total thickness of the applied adhesive and thin material tape;
• the adhesive is heated, it is circulated in a closed circuit conduit and the said flow is caused by removing a fraction of adhesive circulating in the closed circuit conduit;
• the adhesive is heated, it is circulated in a closed circuit duct, the adhesive which circulates in the closed circuit is kept substantially at the temperature which it must have for its flow and the said flow is caused by removing a fraction of adhesive flowing in the closed circuit conduit;
• the adhesive is heated, it is circulated in a closed circuit duct, a fraction of adhesive circulating in the closed circuit is withdrawn, the temperature of the adhesive fraction withdrawn is increased and then the l flow of said fraction.

• * un bâti,
• * des moyens de chauffage dudit adhésif dans le réservoir d'adhésif,
• * des moyens d'obturation et d'ouverture du conduit proches de l'orifice ainsi que des moyens de commande desdits moyens d'obturation et d'ouverture,
• * des moyens de guidage d'un ruban au-dessus d'un cordon épais d'adhésif déposé sur le support,
• * des moyens aptes à exercer une pression simultanée du ruban sur l'adhésif et de l'adhésif sur le support, pression exercée dans une direction substantiellement perpendiculaire à un plan dans lequel doit se trouver le support destiné à recevoir de l'adhésif,
• * des moyens d'évacuation en vue du stockage des ensembles support-adhésif-ruban.

The invention also relates to a device for manufacturing a product consisting of a support on which there is a long-acting adhesive and a protective tape, for a deferred use of said adhesive, of the type comprising an adhesive reservoir and at least one conduit extending from the reservoir to at least one orifice, guides for at least one support intended to receive adhesive, means for setting relative movement of said orifice and at least one support intended to receive adhesive, characterized in that it comprises:

• * a frame,
• * means for heating said adhesive in the adhesive tank,
• * means for closing and opening the duct close to the orifice as well as means for controlling said means for closing and opening,
• * means for guiding a tape over a thick bead of adhesive deposited on the support,
• means capable of exerting simultaneous pressure of the tape on the adhesive and of the adhesive on the support, pressure exerted in a direction substantially perpendicular to a plane in which the support intended to receive the adhesive must be located,
• * evacuation means for the storage of the support-adhesive-tape assemblies.

• il comprend des moyens pour exercer une pression perpendiculairement au plan d'un support destiné à recevoir un adhésif;
• les moyens pour exercer une pression sont constitués par un galet monté rotatif et sollicité vers le plan du support selon une force avantageusement réglable;
• le galet a une largeur supérieure à celle que doit avoir l'adhésif après étalement;
• le galet est molleté et entraîné positivement en rotation;
• il est situé dans un local à température ambiante et les moyens aptes à exercer une pression et un laminage sont éloignés de l'orifice;
• il comprend des moyens de refroidissement positif situés entre l'orifice et les moyens aptes à exercer une pression et un laminage;
• il comprend des moyens de stockage d'au moins un support en carton ou matériau analogue, des moyens de stockage d'au moins un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, des moyens pour déposer de l'adhésif, des moyens de guidage dudit ruban au-dessus d'adhésif déposé sur le support, ainsi que des moyens pour évacuer en vue de stockage l'ensemble support-adhésif-ruban;
• il comprend des moyens pour supporter au moins une bobine de support en carton ou matériau analogue, des moyens pour déposer de l'adhésif, des moyens pour dérouler le support et le faire défiler en regard d'au moins un orifice d'écoulement d'adhésif, des moyens de stockage d'au moins un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, des moyens de guidage dudit ruban au-dessus d'adhésif déposé sur le support, des moyens de pression simultanée du ruban sur l'adhésif et de l'adhésif sur le support, des moyens pour enrouler l'ensemble support-adhésif-ruban selon au moins une bobine et des moyens pour supporter ladite bobine;
• il comprend des moyens de stockage d'au moins une pile de panneaux en carton ou matériau analogue, des moyens de prélévement et de distribution desdits panneaux un par un, des moyens de guidage desdits panneaux, des moyens de déplacement unitaire desdits panneaux en vue de leur défilement en regard d'au moins un orifice d'écoulement d'adhésif, des moyens pour déposer de l'adhésif d'un premier bord que chaque panneau présente à un second bord opposé au premier, des moyens de stockage d'au moins un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, des moyens de guidage dudit ruban au-dessus d'adhésif déposé sur chaque panneau, des moyens de pression simultanée du ruban sur l'adhésif et de l'adhésif sur chaque panneau, des moyens pour découper ledit ruban, des moyens d'évacuation de l'ensemble panneau-adhésif-ruban, et des moyens pour déposer chacun desdits ensembles l'un sur l'autre pour constituer au moins une pile;
• il comprend des moyens de stockage d'au moins une pile de panneaux en carton ou matériau analogue, des moyens de prélévement et de distribution desdits panneaux un par un, des moyens de guidage desdits panneaux, des moyens de déplacement unitaire desdits panneaux en vue de leur défilement en regard d'au moins un orifice d'écoulement d'adhésif, des moyens pour déposer de l'adhésif d'un premier bord que chaque panneau présente à un second bord opposé au premier, des moyens de stockage d'au moins un ruban en matériau mince, imperméable à l'adhésif et faiblement sensible à l'action dudit adhésif, des moyens de guidage dudit ruban au-dessus d'adhésif déposé sur chaque panneau, des moyens de pression simultanée du ruban sur l'adhésif et de l'adhésif sur chaque panneau, des moyens pour découper simultanément ledit ruban et une petite fraction du panneau près des premier et second bords de chaque panneau, des moyens d'évacuation des fractions coupées, des moyens d'évacuation de l'ensemble panneau-adhésif-ruban et des moyens pour déposer chacun desdits ensembles l'un sur l'autre pour constituer au moins une pile;
• il comprend au moins un orifice situé au-dessus d'un plan sur lequel doit se trouver un support afin que l'adhésif devant s'écouler par ledit orifice tombe verticalement sur le support;
• il comprend au moins un orifice à section horizontale circulaire et situé au-dessus d'un plan sur lequel doit se trouver un support afin que de l'adhésif devant s'écouler par ledit orifice tombe verticalement sur le support selon une section circulaire;
• il comprend un bâti, des guides pour au moins un support destiné à recevoir de l'adhésif, au moins un réservoir d'adhésif, des moyens de chauffage dudit adhésif dans le réservoir, au moins un conduit s'étendant en circuit fermé de et vers ledit réservoir, une dérivation en matériau conducteur de la chaleur, qui est raccordée audit conduit, qui se termine par un orifice et qui comprend des moyens d'obturation et d'ouverture, des organes de chauffage étant placés à l'extérieur de ladite dérivation, le dispositif comprenant en outre des moyens de régulation des moyens de chauffage du réservoir et des organes de chauffage de la dérivation.

According to other characteristics of this device:

• it comprises means for exerting pressure perpendicular to the plane of a support intended to receive an adhesive;
• the means for exerting pressure consist of a roller mounted to rotate and urged towards the plane of the support according to an advantageously adjustable force;
• the roller has a width greater than that which the adhesive must have after spreading;
• the roller is soft and positively driven in rotation;
• it is located in a room at room temperature and the means capable of exerting pressure and rolling are distant from the orifice;
• it includes positive cooling means located between the orifice and the means capable of exerting pressure and rolling;
• it comprises means for storing at least one cardboard or similar material support, means for storing at least one ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, means for depositing adhesive, means for guiding said tape over adhesive deposited on the support, as well as means for removing for storage the support-adhesive-tape assembly;
• it comprises means for supporting at least one support spool of cardboard or similar material, means for depositing adhesive, means for unwinding the support and making it pass opposite at least one flow orifice for adhesive, means for storing at least one tape made of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, means for guiding said tape over the adhesive deposited on the support, means simultaneously pressing the tape on the adhesive and the adhesive on the support, means for winding the support-adhesive-tape assembly according to at least one reel and means for supporting said reel;
• it comprises means for storing at least one stack of panels of cardboard or similar material, means for removing and distributing said panels one by one, means for guiding said panels, means for unitary displacement of said panels in order to their running opposite at least one adhesive flow orifice, means for depositing adhesive from a first edge that each panel has at a second edge opposite the first, means for storing at least a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, means for guiding said ribbon over the adhesive deposited on each panel, means for simultaneously pressing the ribbon onto the adhesive and adhesive on each panel, means for cutting said tape, means for removing the panel-adhesive-tape assembly, and means for depositing each of said assemblies one on the other to constitute at least one p Isle;
• it comprises means for storing at least one stack of panels of cardboard or similar material, means for removing and distributing said panels one by one, means for guiding said panels, means for unitary displacement of said panels in order to their running opposite at least one adhesive flow orifice, means for depositing adhesive from a first edge that each panel has at a second edge opposite the first, means for storing at least a ribbon of thin material, impermeable to the adhesive and weakly sensitive to the action of said adhesive, means for guiding said ribbon over the adhesive deposited on each panel, means for simultaneously pressing the ribbon onto the adhesive and adhesive on each panel, means for simultaneously cutting said tape and a small fraction of the panel near the first and second edges of each panel, means for removing the cut fractions, means for evacuation of the panel-adhesive-tape assembly and means for depositing each of said assemblies one on the other to constitute at least one stack;
• it comprises at least one orifice situated above a plane on which there must be a support so that the adhesive which has to flow through said orifice falls vertically onto the support;
• it comprises at least one orifice with a circular horizontal section and situated above a plane on which there must be a support so that the adhesive which has to flow through said orifice falls vertically onto the support in a circular section;
• it comprises a frame, guides for at least one support intended to receive adhesive, at least one adhesive reservoir, means for heating said adhesive in the reservoir, at least one conduit extending in closed circuit from and to said tank, a diversion made of heat conducting material, which is connected to said tank conduit, which ends in an orifice and which comprises closing and opening means, heating members being placed outside said branch, the device further comprising means for regulating the heating means of the tank and bypass heater members.

The invention will be better understood from the detailed description below made with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

Figure 1 is a schematic view of a device according to the invention, applied to obtaining sheets of great length having at least one line of adhesive.

Figure 2 is a schematic view of a device according to the invention, applied to obtaining panels, or plates, having at least one line of adhesive.

Figures 3 and 4 are two schematic views illustrating a phase of the process according to the invention and providing for a preparation of the support before the introduction of the adhesive.

Figure 5 is a schematic view in longitudinal section showing the phase of the process according to the invention which corresponds to the combination of a support, the adhesive and a protective tape.

Figure 6 is a schematic cross-sectional view showing the phase of the process according to the invention which corresponds to the deposition of the adhesive on a support.

Figure 7 is a schematic cross-sectional view showing the phase of the process according to the invention which corresponds to the deposition of the protective tape on the adhesive.

Figure 8 is a schematic cross-sectional view showing the phase of the process according to the invention which corresponds to the combination of the support, the adhesive and the protective tape.

Figures 9 and 10 are partial schematic views illustrating a possibility that gives the method according to the invention for finishing a support having at least one line of adhesive.

Figures 9 and 10 are partial schematic views illustrating a possibility that gives the method according to the invention for finishing a support having at least one line of adhesive.

Figures 11 and 12 are schematic sectional views showing the manner in which the adhesive is associated with a corrugated cardboard support of irregular surface, using the method according to the invention.

FIG. 13 is a partial schematic view illustrating a variant of the method according to the invention according to which the adhesive and the protective tape are deposited in a groove whose depth is equal to the thickness of the adhesive and of the tape. protection.

Figure 14 is a schematic view in longitudinal section of a machine according to the invention and allowing the industrial implementation of the method of the invention.

Figure 14 is a schematic view in longitudinal section of a machine according to the invention and allowing the industrial implementation of the method of the invention.

Figure 15 is a partial schematic view illustrating the implementation of the method according to the invention for obtaining a correct adhesive bead on supports formed by separate panels, or plates.

Figures 16, 17 and 18 are schematic views illustrating the possibility offered by the invention to obtain continuous or discontinuous adhesive tapes.

Figure 19 is a schematic view illustrating a variant of the invention according to which the supports are separate panels while the protective tape is continuous.

Referring to the drawing, it is seen how the implementation of the process according to the invention is carried out.

First of all, in a heated and insulated tank 1, a certain amount of adhesive 2 is heated to about 175 degrees Celsius to bring it to a consistency according to which it is still pasty but at the limit of liquid state. By a conduit 3, the adhesive is brought to an orifice 4 opening above a fixed plane 5 on which a support is placed.

In Figure 1, there is shown the case where the support consists of corrugated cardboard 6 stored in a reel 7. The corrugated cardboard 6 is guided to extend on the plane 5 and to be moved by traction (as is known per se) parallel to this.

Passing vertically from the orifice 4, the corrugated cardboard 6 receives adhesive 2 which flows at a regulated rate so that it is deposited according to a thick bead 10.

After deposition, the temperature of the bead adhesive 10 must be lowered so that its viscosity increases until its consistency is pasty, at the limit of the solid state.

This is a cardboard called "single face", that is to say that it has a corrugated core associated on one of its faces with a single sheet forming a face called "plane".

Here, it is assumed that the room in which the process is carried out is at room temperature and the lowering of the temperature is obtained by simple no heating by adjusting the speed of movement of the corrugated board 6 relative to the fixed support 5.

When the bead 10 has acquired the desired consistency, a pressure is exerted on it intended to cause it to be rolled over its entire length (parallel to the direction of its movement) and, here, its lateral spread (perpendicular to the direction of its movement) .

This pressure is provided by a roller 11 associated with a jack 12 which urges it along arrow F1 in the direction of the fixed support 5.

Thus, the cord 10 is crushed so as to finally have only a fairly small thickness compared to that which it presented before being subjected to the pressure of the roller 11, controlled by the jack 12.

The 6-adhesive corrugated cardboard assembly 2 is then wound in a spiral to form a coil 13.

This constitutes a product according to the invention.

This product being a reel of corrugated cardboard provided with a bead of adhesive 10, is a semi-finished product which can be shaped in any desired manner: printing, cutting, creasing, folding, volume setting, etc. The adhesive can be used during this shaping or later, for example for closing the finished article if it is a container (box, box, case, envelope, etc.).

Adhesive 2-10 is, of course, always active since it is intended to be used later but it must be isolated from the outside so that it is protected from dirt and to avoid the cardboard thus coated accidentally sticks to other objects. For this, a protective tape 15 is provided which is unwound from a reel 16 and which is guided above the bead of adhesive 10 just before it is pressed by the roller 11.

Thus, the adhesive tape 10 is no longer crushed directly but with the interposition of the protective tape 15.

To obtain the desired temperature, and therefore also the desired viscosity, account must be taken not only of the speed of movement of the corrugated cardboard 6 but also of the distance X measured between the orifice 4 and the axis of the roller 11. The more the speed is great, the greater the distance X must be.

To combine a high speed of movement and a small distance X, the bead of adhesive 10 can be subjected to positive cooling means (not shown) such as a flow of cold air or a cooling tunnel.

In Figure 2, there is shown a variant sleon which the support is no longer continuous over a great length but consists of successive individual panels.

The same elements as those in FIG. 1 have the same references. The operations which are common to the two variants will not be described since they have already been explained.

The panels 20 are, for example, of "double-sided" corrugated cardboard, that is to say that they come from cutting from a sheet of corrugated cardboard comprising a corrugated core and a sheet on each of its two faces, to present two so-called flat faces.

It is in a material of this kind that containers of low price are generally created, in particular for shipments by post or by courier.

The panels 20 are stored in a stack from which they are extracted one by one to be individually driven under the orifice 4 and then under the pressure roller 11.

It is good to cause the flow of adhesive 2 through the orifice 4 as soon as the upstream edge of each panel 20 reaches directly above said orifice 4. The words "upstream" and "downstream" must be interpreted by considering the meaning in which the panels 20 move relative to the fixed support 5.

If the adhesive 2 flowed continuously, it would deposit not only on the panels 20 but also on the support 5 which is unmasked between the panels 10.

Each panel 20 being individualized, provision is made here for the protective tape 15 to be interrupted between two successive panels 20 by a cut made as close as possible to the downstream and upstream edges of each panel 20.

It is this solution which appears in FIG. 2, where the panels 20 have been voluntarily shown in several positions and in such a way that the roller 11 is released.

It can thus be seen that the downstream edge of the panel 20 which is located under the coil 16 receives one end of the ribbon 15 which has been cut at the upstream edge of the panel 10 appearing partially to the left of the roller 11.

The ends of the beginning and the end of the cord 10, near the downstream and upstream edges of the panels 10, can then be less regular than its central area.

We will explain below how to eliminate these irregularities.

As explained above, the essential problem of a delayed use adhesive results from the fact that the destination surface is often different from the surface of the support. However, to join the support and the destination surface, the adhesive must necessarily be as effective for one as for the other.

We have just shown how one can apply a well anchored adhesive to a support, in spite of surface irregularities of this support.

We will now describe means making it possible to ensure that the adhesive thus placed will be effectively fixed, later, on a destination surface in order to durably join the support and the destination surface.

It should be remembered that the present invention makes it possible to solve the most difficult problem in this field, namely that which involves a support and a destination surface having surface irregularities.

This recalled, it should also be stressed that an important factor to be taken into account is the adaptability to one another of the support and the destination surface.

Thus, for example, it has been found that this problem is even more difficult to solve with a higher quality corrugated article because the more the quality of the corrugated cardboard increases, the more rigid it is.

But rigidity does not mean that the irregularities have disappeared. The product, on the contrary, presents increased defects: irregularities are always present and, in addition, the support and the destination surface are unable to adapt to each other.

We can better understand this phenomenon if we compare, by exaggeration, corrugated cardboard to a corrugated sheet, because we can easily imagine that it would be impossible to glue two corrugated sheets whose corrugations would not be strictly nested: the contact surfaces would minimal and all the more weak as neither of the two sheets would be able to match the undulations of the other by deformation of its own.

We understand, conversely, that if at least one of the sheets was deformable, for example if it was made of rubber, or else if a deformable seal was inserted between them, the "custom-made" contact surfaces would be increased "and one would finally ensure a correct junction, whatever the orientation of the sheets between them (parallel or more or less crossed undulations) and whatever the transverse shift of the supposedly parallel undulations.

Now transposing these explanations to the more subtle case of a support and a destination surface having surface irregularities, we understand that the more rigid the elements present, the lower the probabilities of a correct bonding, even if it has been ensured that the adhesive is correctly anchored on the support, when the adhesive is placed in the factory.

When, despite this, a rigid support and destination surface are chosen, the invention provides for reducing this rigidity in the area where the adhesive is to be applied.

We see in Figure 3 a section of a corrugated cardboard support 30 assumed to be of high quality: the paper of which it is made is of the long fiber type and of heavy weight.

It has a core 31 of corrugated paper, glued to two opposite external faces 32 and 33.

The parts 34 of the core which extend between the faces 32 and 33 determine longitudinal cells, or channels, 35 and constitute as many spacers which give the support 30 great rigidity and high resistance to crushing, c '' to say that finally, the faces 32 and 33 are very slightly deformable and that their surface irregularities: hollow 36 and bumps 37 are definitively formed.

Applying a face 33 against a face 32 to glue them is the same as trying to glue two corrugated sheets.

According to the invention, the support 30 is prepared for bonding to a destination surface, even before the product is completely produced.

For this, use is made of a pressure means such as a roller 38 rotatably mounted on an axis 39 and biased in a direction perpendicular to the planes of the faces 32 and 33, in order to break the parts 34 forming spacers, without however eliminating any elasticity , on the contrary, between the two opposite faces 32 and 33.

It can be seen in FIG. 4 that the parts 34 are deformed and have folds 34 a thanks to which the support 30 becomes elastic instead of being rigid. It is at the base of this elastic zone that we will deposit the adhesive.

Furthermore, to ensure bonding when using the adhesive 10, pressure is exerted (generally by hand) on the face opposite to that which carries the adhesive 10: if the latter has been applied to a face 32, the opposite face 33 will be pressed. If the support 30 is very rigid, the force is insufficient to deform the face 32.

With a support 30 of the type of that of FIG. 4, the pressure of the hand exerted on one face will be transmitted to the opposite face by allowing it to deform and, consequently, to marry the irregularities of the surface of destination.

Note that the force of the roller 38 slows the movement of the supports 30. To avoid any irregularity of movement, it is good to provide a positive drive of the supports, for example by means of bands or pebble rollers.

However, according to the invention, it is also possible to use the roller 38 itself and, for this, provide for its positive drive by means of a geared motor of known type (not shown) and ensure that its surface in contact with the supports 30 is rough, in particular by knurling, as is known per se.

The flexibility of the support 30, coming from the pleats 34 a is obviously only useful at the level of the adhesive 10, so that if we consider the formation of the pleats 34 a as a weakening, it is of no interest that the area where the adhesive 10 is located and, consequently, does not in any way harm the overall mechanical strength of the support 30.

But it is good that the softening of the support 30 created by the roller 39 extends along a strip a little wider than that which the adhesive 10 will occupy when it is deposited and applied, in order to be assured that the pressure of the hand exerted on the opposite side is largely transmitted to all the adhesive.

Figure 5 on the one hand and Figures 6 to 8 on the other hand are schematic views on a larger scale than the previous ones, allowing to highlight the characteristics of the invention.

While the bead 10 travels the distance X, it cools and freezes and the heating of the adhesive 2 is adjusted so that at the outlet of the orifice 4, it has a consistency such that it deforms sagging.

The orifice 4 has a circular section so that the cord 10, when it is deposited, itself has a circular section (Figure 6).

But as it meets the support, it cannot physically keep this theoretical section and it flattens naturally.

By moving away from the orifice 4, the cord 10 therefore becomes wider and less high (FIG. 5 and FIG. 7).

When the bead 10 is flattened (FIGS. 8 and 9), it offers a non-negligible surface to the protective tape 15 and since the adhesive 2 is chosen for its prolonged effect, sufficient adhesion is obtained between the bead 10 and the tape 15 to avoid any slipping between them.

This arrangement is important because it allows fairly high running speeds despite the resistance offered by the ribbon 15 wound according to the spool 16, when traction is exerted on it.

After the action of the roller 11, the tape 15 is on the adhesive 2 which no longer has the shape of a thick bead but has become a thinner and wider strip (FIG. 8).

The quantity of adhesive 2 delivered by the orifice 4 is established so that after the pressure action of the roller 11, the adhesive strip 10 has a width at most equal to that of the protective tape 15.

The support 20 of FIGS. 2, 5, 9 and 10 comprises a corrugated core 21 as well as two so-called flat faces 22 and 23. The reference 24 denotes the downstream edge of the panel 20 and the reference 25 denotes its downstream edge 24.

On the other hand, in FIG. 9, it can be seen that the strip of adhesive 10 with an irregular width, coming from the casting of adhesive 2 out of the orifice 4, a casting which cannot immediately provide the desired width, unlike what is obtained, according to the known technique, with orifices located in contact with the support to be coated and whose very thin section delivers the adhesive in its almost final form of coating layer. These holes are known as "lip nozzles".

The same phenomenon of irregularity occurs in the vicinity of the upstream edge 25, when the flow of adhesive 2 is interrupted.

In FIG. 5, it can be seen that the casting time is adjusted so that the bead 10 is interrupted a little below the upstream edge 25 because the lamination effected by the roller 11 tends to extend the strip of adhesive longitudinally in the last millimeters of the panel 20 and this must be taken into account so that the adhesive is not spilled out of the panel 20.

If the protective tape 15 has the same width as the adhesive strip 10, the provisions of FIG. 9 (in the vicinity of the two downstream edges 24 and upstream 25) can be accepted because the absence of gluing of the protective tape 15 allows you to easily grasp it by its end when you want to remove it, for the application of the support on the destination surface.

However, by suitably adjusting the degree of adhesion of the tape 15 and of the adhesive 10, it is easy to remove the tape 15 without it being necessary to provide these unattractive arrangements.

They are even less useful when the protective tape 15 is wider than the adhesive strip 10, as shown in FIG. 9.

This is why, when the panels 20 are intended to be cut later, an imperfect mark is removed, according to a characteristic of the invention, so that only the central zone of the strip of adhesive 10 having the desired width remains.

For this, the support 20 is cut along lines 26 and 27.

FIG. 9 shows the drawing of the cutting line 26 to show that it passes as close as possible to the imperfect end of the strip of adhesive 10.

FIG. 10 shows the two oblique and symmetrical cut lines 26 and 27 which give the panel 20 a very attractive quality of appearance and finish.

In certain cases, it turns out to be necessary to finish the panels 20 by removing a more or less wide selvedge, all along their two downstream 24 and upstream edges 25. This advantage is then used to remove the imperfect margins . In this case, obviously, the lines 26 and 27 can no longer be oblique but located in the extension of the downstream 24 and upstream 25 edges.

It is good to carefully adjust the pressure force exerted by the roller 11 in order to obtain not only a crushing of the adhesive bead 10 but also a rolling effect, that is to say that the roller 11 does not follow the irregularities of the support and remains on the contrary at a constant distance from the nominal level of the plane 5.

In this way, it is ensured that the upper face of the strip of adhesive 10 will be both continuous and flat.

This is illustrated in Figures 11 and 12.

FIG. 11 shows a panel 20 on which a strip of adhesive 10 has been deposited, as indicated above, transversely with respect to the corrugations of the core 21.

We see that the outer faces 22 and 23 are not absolutely flat but have depressions opposite the concave parts of the core 21. These irregularities are sometimes difficult to perceive with the naked eye but they are sufficient to make it practically impossible to economical adhesive application directly to the cardboard.

Tests have shown that the application of adhesive to such a support, using the method according to the invention, provides an adhesion surface greater than that which can be obtained with a "lip nozzle" of known type. , applying the same amount of adhesive.

The reason is that with a "lip nozzle" the adhesive is deposited everywhere on the support but that, when fixing it on the destination surface, only the tops of the irregularities, ie -to say the parts located opposite the convex undulations, make contact.

This result cannot be satisfactory because the aim is not only to deposit adhesive on a support. It is above all to allow this adhesive to reunite, subsequently, the support and the destination surface in a rapid, robust and long-lasting manner.

However, the probabilities are high so that the concave irregularities of the support are precisely opposite concave irregularities of the destination surface and the adhesive fragments opposite concave irregularities. The bonding is then uncertain. It is uncertain when the attachment takes only a few hours and the assembled parts detach from each other because the adhesion surface provides less resistance to the forces and stresses which stress the assembled parts.

According to the invention, the adhesive fills the concave irregularities and also covers the convex irregularities according to a significant thickness for the subsequent fixing of the support on the destination surface, whatever the irregularities of the latter since the adhesive has a surface to both continuous and flat.

In FIG. 11, it can be seen that the strip of adhesive 10 has a thickness E opposite the concave irregularities and another thickness e opposite the convex irregularities. Its outer face 10 a is flat and continuous.

FIG. 12 shows the same characteristics in the case where the strip of adhesive 10 is parallel to the corrugations of the core 21 and no longer perpendicular.

The negative effects of an insufficient adhesive can only be combated, according to the state of the art, by improving the condition of the surfaces present, in particular by choosing thick papers, with long fibers and of high cost.

The invention overcomes this drawback since it allows the choice of thin and inexpensive papers.

In this regard, it is known that the panels 20 often have faces 22 and 23 of different qualities. For reasons of rationalization, we choose a good quality paper, with long fibers, for the side intended to be outside the finished cardboard object (a container for example) whereas for the side intended to be inside, and therefore not visible, we choose a more ordinary paper, short fibers, such as recycled paper.

The adhesive 2 must precisely be deposited on the ordinary inner face (support) which is intended to be fixed on the outer face of better quality (destination surface).

Thanks to the invention, it is therefore possible to adopt the usual methods for choosing the qualities, without fear of defective bonding.

The extra thickness created by a strip of adhesive 10 and its protective tape 15 located asymmetrically, has drawbacks for the storage on reel 12 of the corrugated cardboard 6 (FIG. 11) or for the storage in a stack of panels 20. Or the coil 13 becomes frustoconical instead of being cylindrical, or the panels 20 are placed askew instead of being flat.

To avoid this drawback, the invention provides first of all to create a hollow over the entire location of the adhesive strip 10, at a depth equal to the total thickness of the adhesive strip 10 and the protective tape. 15.

This operation is easy to perform when the support is made of corrugated cardboard because it is a fairly soft material which deforms well.

It is described below with the embodiment of the invention according to which the support is a panel 20.

This hollow, or groove, 28 is formed upstream of the orifice 4 and can be obtained by means of a roller 14 driven in rotation and subjected to a pressure force directed perpendicularly to the face 22 of the panel 20, in order to obtain a sagging of the undulations of the soul 21, as shown diagrammatically in FIG. 13.

Controlling the temperature of the adhesive 2 deposited on the support is very important since this temperature conditions the consistency of the bead 10 and the smooth running of the process according to the invention.

If one acted as simply as suggested by the diagram of FIGS. 1 and 2, one would risk having at the orifice 4 an adhesive of insufficient temperature, due in particular to the lowering of temperature in the conduit 3. A first precaution therefore consists of insulating the conduit 3, to avoid excessive temperature drops.

This, however, may prove to be insufficient and, according to the invention, a closed circuit is created in which the adhesive 2 circulates from the reservoir 1. This circuit is thus maintained at a known and stable temperature. Then, the adhesive 2 is caused to flow through the orifice 4 by sampling in this circuit and the adhesive is heated to the immediate vicinity of the orifice 4 to obtain the desired temperature with great precision (from the order of a few degrees Celsius).

For the implementation of the invention, it is advantageous to use a non-aqueous adhesive, so that it is not absorbed by the support when the latter is hydrophilic, as is the case with cardboard.

Such an adhesive is, for example, a styrenisoprene-styrene without addition of solvents, having a viscosity of the order of 10,000 centipoise.

Referring now to Figures 14 and 15, there is shown a device for implementing the invention constituting a complete machine ensuring common functions (supplying panels for example) and specific functions of the invention.

The ordinary functions are provided by mechanisms known to those skilled in the art and their description will be limited to understanding the invention.

The machine comprises a frame 40, guides for belts 41 constituting together a means of translation of the supports 20 relative to the machine itself. The belts 41 are in support at all the places where they undergo pressure forces (rollers 11 and 14 in particular).

The plane on which the panels are placed here consists of all of the translation belts 41.

These are engaged on drive pinions 42 and on tension pinions 43.

At one end of the machine, there is a known type of mechanism, called a "feeder", 44 containing a stock of stacked supports 20 and comprising means 45 for removing these supports 20 to direct them one by one towards the belts 41 which drive them to the other end of the machine.

Above the belts 41, there is the reservoir 1, the orifice 4 and an assembly 46 ensuring the supply of the protective tape 15 and the actuation of the pressure roller 11.

The general operation of this device is as follows:
The panels 20 are removed by the mechanism 45 and are supported by the belts 41 associated, as is known, with counter-belts together ensuring the maintenance and the translation of each support 20.

As soon as the downstream edge 24 of a panel 20 is plumb with the orifice 4, a detector 50 (FIG. 15) causes the flow of adhesive through said orifice 4 and this until a another detector 51 (FIG. 15) perceives the arrival at its level of the upstream edge 25 of the panel 20, this detector 51 then causing the flow of adhesive through the orifice 4 to be interrupted.

Another detector 52 (FIG. 15) supplies the protective tape 15 as soon as the upstream edge 24 of the panel 20 approaches the plumb of the pressure roller 11. The tape 15, as explained above, adheres to the cord d adhesive 10 which has been deposited and is entrained with it under the roller 11. As soon as the upstream edge 25 of the panel 20 occurs, the other detector 53 (FIG. 15) causes the cross section of the protective tape 15 and, if necessary if necessary, stopping the mechanism (not shown) for unwinding and delivering the ribbon 15.

The panel 20 provided with an adhesive strip 10 and a protective tape 15 constitutes a product according to the invention.

It is a semi-finished product that can be shaped in any desired way: printing, cutting, creasing, folding, volume setting, etc. The adhesive can be used during this shaping or later, for example for closing the finished article if it is a container (box, box, case, envelope, etc.)

When the machine is served with rigid panels, like the panels 30 in FIGS. 3 and 4, use is made of the roller 38 which is located between the feeder 44 and the orifice 4. Thus, the softening zone is created just before that the adhesive 2 does not flow on it, coming from the orifice 4.

The pressure exerted by the roller 38 is advantageously adjustable so that the machine can be used with supports of different stiffnesses, requiring variable pressures.

This can be obtained, as is known per se, by means of a jack (not shown) whose rod acts on the axis 39.

If the supports used are not very rigid and do not require crushing, the roller 38 is neutralized.

FIG. 15 illustrates the coordination of the various specific functions of the machine with an embodiment particularly well suited to controlling the flow temperature of the adhesive.

The tank 1 is associated with a closed external circuit comprising the duct 3 and a return 70 on which there is a pump 71. The tank 1 is surrounded by an electrical heating resistor 72 protected by a heat-insulating lining 73.

A conduit 74 terminates in the orifice 4 and is connected to the closed circuit 3 - 70 of which it constitutes a bypass which receives a solenoid valve 75 acting by all or nothing: "open" or "closed". The bypass is surrounded by a heating resistor 76 protected by a heat-insulating lining 77 as close as possible to the orifice 4.

During the whole operation of the machine, the resistor 72 is supplied and a hermostat 80 associated with a contact 81 of a relay controls this supply to maintain the mass of adhesive 2 in pasty form at the limit of the liquid state and at good temperature. The pump 71 ensures the permanent circulation of adhesive 2 to prevent a temperature gradient from being established between the upper layers and the lower layers of adhesive 2. This gives a stable temperature of the entire mass of adhesive 2 , pretty much.

The detector 50 is positioned so that it detects the downstream edge 24 of a panel 20 sufficiently in advance so that the substantially liquid adhesive 2 flows at the right temperature as soon as this downstream edge 24 is perpendicular to orifice 4, taking into account the following parameters:
The detector 50 actuates the solenoid valve 75, which causes the expulsion of adhesive 2 from the closed circuit and its flow by the bypass 74.

This is heated by the resistor 76 to transfer calories to the flowing adhesive 2, which is why the bypass is made of heat conducting material.

The temperature to which the bypass 74 is brought and its length are established to obtain at the orifice 4 the desired temperature for the adhesive 2 to one or two degrees Celsius.

The detector 51 is positioned in such a way that it causes the solenoid valve 75 to close in time so that no more adhesive 2 flows beyond the downstream edge of the panels 20 taking account of the length of bypass 74, the contents of which continue to flow after the solenoid valve 75 has been closed.

Furthermore, the double-acting cylinder 12 is supplied with pressurized fluid by two pipes (only one 82 is shown diagrammatically to simplify the drawing, this mechanism being within the reach of the skilled person) controlled by at least one solenoid valve 83. The control of this solenoid valve 83 is subjected to a feeler (not shown) either pre-adjusted or subject to parameters taking into account the thickness desired for the adhesive strip 10, the quality of the carton, the irregularities of its faces, etc.

The mechanism 46 will not be described in detail since it can be of different known types, more or less complex and comprising, consequently, more or less numerous command, guidance and control members. Its control was schematized overall by a solenoid valve 84.

The solenoid valves 83 and 84 are slaved to the detectors 52 and 53 so that the delivery of protective tape 15 and the distance of the roller 11 from the surface of the panels 20 are constantly monitored and coordinated with the presence and absence of panels 20 on belts 41 in the appropriate place.

The electrical circuit is connected to a current source 85 and includes a general switch 86.

The heating resistor 76 is regulated by a thermostat 87 which controls a switch 88.

Naturally, in practice, this schematic circuit is more complex, in particular because it is combined with electronic circuits and components.

The implementation of the invention does not require the adhesive bead to be continuous.

In FIG. 16, a continuous strip of adhesive 10 is shown schematically, but in FIGS. 17 and 18, other solutions are shown.

FIG. 17 illustrates an example according to which the strip of adhesive is formed by the juxtaposition of three narrow strips 10 a , 10 b and 10 c .

The strip is therefore discontinuous when considered in its width, but, on the other hand, each of these strips is continuous in the longitudinal direction.

FIG. 18 illustrates an example according to which the strip of adhesive is constituted by the justaposition of points 10 d arranged in longitudinal and transverse lines. They could also be arranged in longitudinal lines but offset, for example in staggered rows, in the transverse direction.

The strip is therefore discontinuous but both longitudinally and transversely.

If a discontinuous solution is adopted, the total amount of adhesive must remain substantially the same as that of a continuous strip, in order to obtain good fixing of the support on the destination surface.

This means that a discontinuous strip of the kind of that of FIG. 17 or of FIG. 18 has a total width greater than that of a continuous strip 10 like that shown in FIG. 16.

The adhesive, set up in the factory before delivery to the customer, can be deposited directly on the final product and is masked by the protective tape which can be of any color, including white and of attractive appearance.

The invention therefore applies well, not only to brown corrugated articles, but also to corrugated articles or other white material.

Referring now to Figure 19, we see that we can both use separate panels (and therefore discontinuous) and a continuous protective tape.

Shematically shown are five panels 20 a , 20 b , 20 c , 20 d and 20 e and a continuous protective tape 15, therefore passing over the spaces 90, 91, 92 and 93 which separate two panels 20 successive.

To individualize the products consisting of a panel 20, an adhesive strip 10 and a protective tape 15, it is necessary to cut the latter. In practice, the cut is made between two panels 20, immediately after the ribbon 15 has been fixed to the second panel.

The diagram in FIG. 19 therefore does not correspond to this hypothesis, but it has been retained in spite of this because it simplifies the understanding of the different cutting possibilities which will now be described.

The ribbon 15 which passes over the space 90 existing between the panels 20 a and 20 b is intact, that is to say that it is not cut.

Significantly in the middle of the space 91 which exists between the panels 20 b and 20 c is a dashed line 94 which indicates a straight cut (transverse to the ribbon 15) which, repeated at the right of each space, leaves two tongues remaining 15 a and 15 b . Each finished panel 20 therefore has two tabs: the tab 15 a on the side of its upstream edge 25 and the tab 15 b on the side of its downstream edge 25.

The presence of these tabs can be desired to facilitate the removal of the protective tape 15 when the adhesive strip 10 is to be used, leaving the user the choice of grasping which of these two tabs seems to him the most dresser.

Significantly against the downstream edge 24 of the panel 20 d , which is a limit of the space 92 which exists between the panels 20 c and 20 d , is a dashed line 95 which indicates a straight cut (transverse to the ribbon 15) which, repeated for each space, leaves only one tab 15 c . Each finished panel 20 therefore has a single tongue 15 c .

The presence of this tab can be desired to facilitate the removal of the protective tape 15 when the adhesive strip 10 must be used, but here the user no longer has the choice between two tabs. On the other hand, the tongue 15 c is longer (practically double) than each of the tongues 15 a and 15 b , which can facilitate the removal of the ribbon 15.

Significantly against the two downstream 24 and upstream 25 edges of the panels 20 d and 20 e which delimit the space 93 which exists between the panels 20 d and 20 e , there is a line in mixed lines respectively 96 and 97 which each indicate a section straight (transverse to the ribbon 15), which, repeated for each space, leave no tongue but a fragment of ribbon 15 d constituting a scrap to be eliminated. The finished panels 20 therefore have no tongue.

This solution may be desired when the products thus obtained are intended to be subsequently shaped mechanically, since the presence of one or two tongues may be discouraged, or even prohibited, if they risk catching in moving mechanical parts, for example. example, and then disrupt the functioning of the machines.

However, in all cases, it is possible to prefer the embodiment which has just been described with reference to FIG. 19 when a high machine throughput is sought.

Indeed, the installation of a segment of ribbon 15 for each panel has the consequence that we must be satisfied with a relatively slow production rate because we must allow the first millimeters of the ribbon 15 time to stick to the cord adhesive 10.

By laying the tape 15 continuously, there is only one primer, at the start of production, and there is no longer any fear of the tape 15 coming off even at high speed because the strong traction which results on the tape 15 for unwinding it is balanced by a considerable resistance to detachment, because the tape extends continuously over the length of two panels 20.

This production gain can more than offset the increase in the amount of ribbon consumed.

In addition, as the tape is retained by the adhesive strip 10 of two successive panels, the intensity of the bonding can be lowered, which allows the use of inexpensive tapes 15 and which makes it possible to remove this tape 15 more easily when using the adhesive strip 10.

Claims (40)

1. Method for manufacturing a product consisting of a substrate (6-20), in particular a substrate of fibrous material, of which at least one face exhibits irregularities and on which are located a prolonged-effect adhesive (2-10) and a protective tape (15) for the purpose of delayed use of said adhesive (2-10), of the type including the steps whereby the adhesive is deposited, then it is subjected to a pressure, characterised in that the adhesive (2) is heated to a temperature at which it is pasty at the limit of the liquid state, then it is conducted to at least one orifice (4) opening out above a plane (5) on which the substrate (6-20-30) is placed, then flow thereof is caused at the same time as relative movement is caused between the substrate (6-20-30) and the orifice (4) so that the adhesive (2) is deposited on the substrate (6-20-30) either in at least one particularly continuous thick string or in a series of separate deposits, the temperature of the adhesive (2) deposited is lowered to increase its viscosity until it is pasty at the limit of the solid state, then the protective tape (15) is applied to the adhesive string or strings (10), then there is exerted on the protective tape (15) a pressure designed to cause rolling, as well as crushing of the string or lateral spreading of the string which may result from rolling, over its whole length so that, after exerting this pressure, the string (10) occupies only a fraction of the width of the substrate (6-20), then if occasion arises at least one subsequent operation of cutting up the product consisting of a substrate (6-20-30), an adhesive strip (2-10) and a protective tape (15) is performed.
2. Method according to claim 1, characterised in that the product is designed to be shaped after placement of the adhesive (2) and of the protective tape (15), so as to form a finished article ready for use by employing the adhesive (2) exposed by withdrawal of the protective tape (15).
3. Method according to claim 1, characterised in that, the substrate (30) being made of a relatively rigid material, it is subjected to a force of pressure localized in the zone in which flow of the adhesive (2) is to be caused, so as to obtain softening of the substrate (30) which, in this zone, thus becomes more flexible than originally.
4. Method according to claim 3, characterised in that the force of pressure relates to a strip of which the width is greater than that of the adhesive (10) after application.
5. Method according to claim 3, characterised in that the force of pressure is calibrated to be greater than the elastic strength of the material forming the substrate (30).
6. Method according to claim 3, characterised in that, the material of the substrate having a cellular internal structure, as is the case with corrugated cardboard of which the channels (31-34) create longitudinal cells (35), the force of pressure is calibrated to be capable of breaking the walls (34) of the cells (35) forming struts between two opposed faces (32 and 33) of the substrate (30), but insufficient to suppress all elasticity perpendicular to said faces (32 and 33).
7. Method according to claim 1, characterised in that, the method being implemented in a room at ambient temperature, the temperature of the adhesive (2-10) is lowered by simple lack of heating and while causing the relative movement at a speed such that the time which passes between deposition of the adhesive (2) and application thereof by pressure corresponds to the desired temperature drop.
8. Method according to claim 1, characterised in that, the method being implemented in a room at ambient temperature, and the relative movement having a given speed, a pressure is exerted on the adhesive (2-10) at a distance from the flow orifice (4) such that the time which passes between deposition of the adhesive (2-10) and application thereof by pressure corresponds to the desired temperature drop.
9. Method according to claim 1, characterised in that, after deposition, the adhesive string (10) is subjected to positive cooling means such as a stream of cold air.
10. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like material, a tape (15) of thin material impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10) previously deposited on the substrate (6-20) and, in order to apply the adhesive string (10) to the substrate (6-20), a pressure is exerted on the tape (15).
11. Method according to claim 1, characterised in that, the substrate (6) being made of cardboard or like material wound up in a long length in the form of a reel (7), at least one longitudinal adhesive string (10) is deposited at the same time as the substrate (6) is unwound, a tape (15) of thin material impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the string (10), in order to apply the adhesive string (10) to the substrate (6), a pressure is exerted on the tape (15) and this assembly (6-10-15) is wound onto a reel (13) for the purpose of storage thereof.
12. Method according to claim 1, characterised in that, the substrate (6) being made of cardboard or like material wound up in a long length in the form of a reel (7), at least one longitudinal adhesive string (10) is deposited at the same time as the substrate (6) is unwound, a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the string (10), in order to apply the adhesive string (10) to the substrate (6), a pressure is exerted on the tape (15), this assembly (6-10-15) is wound onto a reel (13) for the purpose of storage thereof, then before use of the adhesive (2), the substrate (6) is cut up into panels designed to form blanks, particularly for obtaining containers.
13. Method according to claim 1, characterised in that, the substrate being a panel (20) made of cardboard or like material, at least one adhesive string (10) is deposited on said panel (20) from a first edge (24) which the latter comprises to a second edge (25) opposed to the previous one (24), a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the string (10), in order to apply the adhesive string (10) to the substrate (20), a pressure is exerted on the tape (15) then, if occasion arises, imperfect margins are eliminated.
14. Method according to claim 1, characterised in that, the substrate being a panel (20) made of cardboard or like material, several panels (20) supplied one after the other, leaving a space (90-93) between them, are treated, at least one adhesive string (10) is deposited on each panel (20) from a first edge (24) which they comprise to a second edge (25) opposite the previous one (24), a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the string (10), which tape (15) is continuous and extends from one panel (20) to another over the space (9093) which separates them and, in order to apply the adhesive string (10) to each panel (20), a pressure is exerted on the tape (15) directly above each panel (20), then cutting up of the tape (15) between the panels (20) is performed.
15. Method according to claim 14, characterised in that cutting up is performed against the two opposed edges (24 and 25) of each panel (20).
16. Method according to claim 14, characterised in that cutting up is performed between the two opposite edges (25 and 24) of two adjacent panels (20).
17. Method according to claim 14, characterised in that cutting up leaves at least one segment (15a-15b-15c-15d) of tape (15) beyond at least one of the edges (24 or 25) of each panel (20).
18. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like material, a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10) deposited, in order to apply the adhesive string (10) to the substrate (6-20), a pressure is exerted on the tape (15), the quantity of adhesive (2) deposited and the value of the pressure exerted on the tape (15) being coordinated in such a way that, after application of the string (10), the width which the adhesive (2-10) occupies on the substrate (6-20) is at most equal to that of said tape (15).
19. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like material, a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10) deposited, and application of the string (10) is caused only when the temperature to which it has dropped after deposition on the substrate (6-20) has increased its viscosity sufficiently for its degree of adherence to the tape of thin material (15) to be distinctly lower than the degree of adherence which it has with the substrate (6-20).
20. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like material, flow of the adhesive (20) is caused through an orifice (4) which has a section and an orientation such that the adhesive string (10) deposited by flow has a substantially circular section, the tape of thin material (15) is placed at a certain distance from said orifice (4) while coordinating this distance, the temperature at which the adhesive (2) is deposited on the substrate (6-20) and the speed of relative displacement, so that the adhesive string (10) laterally yields slightly, then a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10) , and in order to apply the adhesive string (10) to the substrate (6-20), a pressure is exerted on the tape (15).
21. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like material, at least one adhesive string (10) is deposited, a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10), in order to apply the adhesive string (10) to the substrate (6-20), a pressure is exerted on the tape (15), at least one adhesive string (10) is deposited and rolled in sufficient quantity for the string (10) , after application thereof, to fill all said irregularities and further offer the tape of thin material (15) a plane and continuous surface.
22. Method according to claim 1, characterised in that, the substrate (6-20) being made of cardboard or like deformable material, the substrate (6-20) is flattened at least in the zone which is to receive said adhesive (2), at least one adhesive string (10) is deposited, a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on the adhesive string (10) and, in order to apply the adhesive string (10) to the substrate (6-20), a pressure is exerted on the tape (15).
23. Method according to claim 1, characterised in that, the substrate (20) being made of cardboard or like deformable material, a regular cavity (28) is formed over the whole zone which is to receive said adhesive (2-10), at least one adhesive string (10) is deposited in said cavity (28), a tape of thin material (15) impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10) is placed on said string (10), in order to apply the adhesive string (10) in the cavity (28) of the substrate (20) a pressure is exerted on the tape (15), the depth of said cavity (28) being substantially equal to the total thickness of the applied adhesive (2-10) and of the tape of thin material (15).
24. Method according to claim 1, characterised in that the adhesive (2) is heated, it is circulated in a closed-circuit pipe (3-70) and said flow is caused while taking a fraction of adhesive (2) circulating in the closed-circuit pipe (3-70).
25. Method according to claim 1, characterised in that the adhesive (2) is heated, it is circulated in a closed-circuit pipe (3-70), the adhesive (2) which is circulating in the closed-circuit pipe (3-70) is maintained substantially at the temperature which it is to have for flow thereof and said flow is caused while taking a fraction of adhesive (2) circulating in the closed-circuit pipe (3-70).
26. Method according to claim 1, characterised in that the adhesive (2) is heated, it is circulated in a closed-circuit pipe (3-70), a fraction of adhesive (2) circulating in the closed-circuit pipe (3-70) is taken, the temperature of the adhesive fraction (2) taken is increased and then flow of said fraction is caused.
27. Device for manufacturing a product consisting of a substrate on which are located a prolonged-effect adhesive and a protective tape, for the purpose of delayed use of said adhesive, of the type including a reservoir of adhesive and at least one pipe extending from the reservoir to at least one orifice, guides for at least one substrate designed to receive adhesive, means for setting in relative movement said orifice and at least one substrate designed to receive adhesive, characterised in that it includes:

    - a frame (40),

    - means for heating said adhesive (2) in the reservoir (1) of adhesive,

    - means (75) close to the orifice (4) for closing and opening the pipe (3-74) as well as means (50 to 53) for control of said closing and opening means (75),

    - means for guiding a tape (15) above a thick adhesive string (10) deposited on the substrate (20),

    - means (11-12) capable of exerting a simultaneous pressure of the tape (15) on the adhesive (2-10) and of the adhesive (2-10) on the substrate (6-20), which pressure is exerted in a direction substantially perpendicular to a plane in which is to be located the substrate (20) designed to receive adhesive (2),

    - means (41-60-61) for discharge for the purpose of storage of the substrate (20)-adhesive (10)-tape (15) assemblies.
28. Device according to claim 27, characterised in that it includes means (38-39) for exerting a pressure perpendicularly to the plane of a substrate (30) designed to receive an adhesive (2-10).
29. Device according to claim 28, characterised in that the means for exerting a pressure consist of a roller (38) mounted rotatably and biased towards the plane of the substrate (30) by an advantageously adjustable force.
30. Device according to claim 28, characterised in that the roller (38) has a width greater than that which the adhesive (10) is to have after spreading.
31. Device according to claim 28, characterised in that the roller (38) is knurled and driven positively in rotation.
32. Device according to claim 27, characterised in that it is situated in a room at ambient temperature and the means (11-12) capable of exerting a pressure and rolling are remote from the orifice (4).
33. Device according to claim 27, characterised in that it includes positive cooling means situated between the orifice (4) and the means (11-12) capable of exerting a pressure and rolling.
34. Device according to claim 27, characterised in that it includes means (7-44) for storing at least one substrate (6-20) made of cardboard or like material, means (16) for storing at least one tape (15) of thin material impermeable to the adhesive (2) and mildly sensitive to the action of said adhesive (2), means (1-3-4) for depositing adhesive (2), means for guiding said tape (15) above adhesive (2-10) deposited on the substrate (6-20), as well as means (13-60) for discharge for the purpose of storage of the substrate (6-20)-adhesive (10)-tape (15) assembly.
35. Device according to claim 27, characterised in that it includes means for supporting at least one reel (7) of substrate (6) made of cardboard or the like material, means (1-3-4) for depositing adhesive (2), means for unwinding the substrate (6) and passing it opposite at least one orifice (4) for flow of adhesive, means (16) for storing at least one tape (15) of thin material impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10), means for guiding said tape (15) above adhesive (2-10) deposited on the substrate (6), means (11-12) for simultaneous pressure of the tape (15) on the adhesive (2-10) and of the adhesive (2-10) on the substrate (6), means for winding the substrate (6)-adhesive (2-10)-tape (15) assembly on at least one reel (13) and means for supporting said reel (13).
36. Device according to claim 27, characterised in that it includes means (44) for storing at least one pile of panels (20) made Of cardboard or like material, means (45) for taking and distributing said panels (20) one by one, means for guiding said panels (20), means (41) for unit displacement of said panels (20) for the purpose of passing them opposite at least one orifice (4) for flow of adhesive, means (1-3-4, 50 to 53) for depositing adhesive (2-10) from a first edge (24) which each panel (20) comprises to a second edge (25) opposed to the first one (24), means for storing at least one tape (15) of thin material impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10), means for guiding said tape (15) above adhesive (2-10) deposited on each panel (20), means (11-12) for simultaneous pressure of the tape (15) on the adhesive (2-10) and of the adhesive (2-10) on each panel (20), means for cutting up said tape (15), means (41-60) for discharge of the panel (20)-adhesive (2-10)-tape (15) assembly and means for depositing each of said assemblies (20-2-10-15) one on top of the other to form at least one pile.
37. Device according to claim 27, characterised in that it includes means (44) for storing at least one pile of panels (20) made of cardboard or like material, means (45) for taking and distributing said panels (20) one by one, means for guiding said panels (20), means (41) for unit displacement of said panels (20) for the purpose of passing them opposite at least one orifice (4) for flow of adhesive (2), means (1-3-4, 50 to 53) for depositing adhesive (2) from a first edge (24) which each panel (20) comprises to a second edge (25) opposite the first one (24), means for storing at least one tape (15) of thin material impermeable to the adhesive (2-10) and mildly sensitive to the action of said adhesive (2-10), means for guiding said tape (15) above adhesive (2-10) deposited on each panel (20), means (11-12) for simultaneous pressure of the tape (15) on the adhesive (2-10) and of the adhesive (2-10) on each panel (20), means for simultaneously cutting up said tape (15) and a small fraction of the panel (20) near the first and second edges (24 and 25) of each panel (20), means for discharge of the cut fractions, means (41-60) for discharge of the panel (20)-adhesive (2-10)-tape (15) assembly and means for depositing each of said assemblies (20-2-10-15) one on top of the other to form at least one pile.
38. Device according to claim 27, characterised in that it includes at least one orifice (4) situated above a plane on which is to be located a substrate (6-20) so that the adhesive (2) which is to flow through said orifice (4) drops vertically onto the substrate (6-20).
39. Device according to claim 27, characterised in that it includes at least one orifice (4) of circular horizontal section situated above a plane on which is to be located a substrate (6-20) so that adhesive (2) which is to flow through said orifice (4) drops vertically onto the substrate (6-20) in a circular section.
40. Device according to claim 27, characterised in that it includes a frame (40), guides for at least one substrate (6-20) designed to receive adhesive (2), at least one reservoir (1) of adhesive (2), means (72) for heating said adhesive (2) in the reservoir (1), at least one pipe (3-70) extending in a closed circuit to and from said reservoir (1), a branch pipe (74) made of heat-conducting material which is connected to said pipe (3-70), which ends in an orifice (4) and which includes closing and opening means (75), heating members (76) being placed on the outside of said branch pipe (74), the device further including means for regulating the means (72) for heating the reservoir (1) and the members (76) for heating the branch pipe (74).

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