Method and machine for coupling laminar elements

Abstract

A method for coupling laminar elements which are constituted by at least one first laminar sheet (A) and at least one second laminar sheet (B) which are mutually superimposed, which consists in: depositing a predefined amount of a thermally activateable adhesive substance on a first face (A1) of the first laminar sheet (A); heating, for a predetermined time interval, the first face (A1) of the first sheet (A) on which the adhesive substance is deposited, by means of a device of the type of a burner (2), for rapid heating of the adhesive substance; juxtaposing a first face (B1) of the second laminar sheet (B) against the first face (A1) on which the adhesive substance, activated as a result of the localized heating produced by the burner (2), is deposited; subjecting the first laminar sheet (A) and the second laminar sheet (B) to mutual compression for their compaction, so defining a layered laminar element (P).

Description

[0001] METHOD AND MACHINE FOR COUPLING LAMINAR ELEMENTS The present invention relates to a method and a machine for coupling laminar elements.

[0002] In particular, in the present description one relates to the coupling of sheets of materials chosen from among fabric, derivatives of fabrics, nonwoven fabric, derivatives of non-woven fabrics, polymers, leather, derivatives of leather, imitation leather (or eco-leather), derivatives of imitation leather (or eco-leather), paper, derivatives of paper, foils and meshes in fibers of any kind (such as for example carbon fibers, natural fibers, polymeric fibers, glass fibers, aramid fibers including in particular Kevlar fibers, ceramic fibers, mineral fibers, and combinations thereof).

[0003] The coupling of laminar sheets is increasingly used because it makes it possible to provide materials offering high performance in several areas: ultimately, by means of layering, a composite material is obtained that combines the strengths of the sheets that make it up.

[0004] In a great many sectors (which include, by way of non-limiting example, clothing, furnishing, automotive, sporting equipment and others) these materials are gaining high importance.

[0005] There are two coupling techniques normally in use: coupling by means of melting a thermoplastic polymer, which constitutes the adhesive, to be interposed between the two materials prior to juxtaposing them and pressing them together, and coupling by means of depositing adhesive material between the two sheets to be coupled and subjecting the layered assembly to predefined temperatures for a sufficient time to ensure that the adhesive softens and interpenetrates the two materials, bonding them.

[0006] Coupling by melting ensures a good rapidity of execution, but is not indicated for all materials to be coupled, and is often restricted to the production of specific categories of layered composites.

[0007] The space occupied by the machinery used in this method is contained. By contrast, the coupling method that entails the interposition of thermally activateable adhesive between the sheets makes it possible to operate on the near-totality of materials of potential interest, and ensures high standards of quality of the layered composite produced. Against this, however, this technology offers very low productivity, with speeds of coupling sheets varying from approximately 6 meters per minute up to a maximum of the order of 12 meters per minute.

[0008] Furthermore, the machinery used for this type of method is generally rather cumbersome and, in some cases, also requires the presence of drying ovens (more correctly, ovens for stabilizing the adhesive so that it ensures perfect cohesion between the two sheets), which further increases the length of the plant.

[0009] The aim of the present invention is to solve the abovementioned drawbacks, by providing a method for coupling laminar elements that can be applied substantially on any type of sheets to be coupled.

[0010] Within this aim, an object of the invention is to provide a method for coupling laminar elements with high productivity, in particular with a production speed higher than 12 meters per minute.

[0011] Another object of the invention is to provide a method for coupling laminar elements that makes it possible to obtain layered composite materials that are very stable and long-lasting over time.

[0012] Another object of the invention is to provide a method for coupling laminar elements that makes it possible to obtain layered composite materials of high quality, both in terms of aesthetics and in terms of performance and function.

[0013] Another object of the invention is to provide a machine for coupling laminar elements that is suitable for coupling any type of sheets.

[0014] Another object of the invention is to provide a machine for coupling laminar elements that offers reduced space occupation.

[0015] Another object of the present invention is to provide a method and a machine for coupling laminar elements that are low cost, easily and practically implemented, and safe in use.

[0016] This aim and these and other objects that will become more apparent hereinafter are achieved by a method for coupling laminar elements which are constituted by at least one first laminar sheet and at least one second laminar sheet which are mutually superimposed, characterized in that it consists in:

[0017] - depositing a predefined amount of a thermally activateable adhesive substance on a first face of said first laminar sheet;

[0018] - heating, for a predetermined time interval, said first face of said first sheet on which said adhesive substance is deposited, by means of a device of the type of a burner, for rapid heating of said adhesive substance;

[0019] - juxtaposing a first face of said second laminar sheet against said first face of said first sheet on which said adhesive substance, activated as a result of the localized heating produced by said burner, is deposited;

[0020] - subjecting said first laminar sheet and said second laminar sheet to mutual compression for their compaction, so defining a layered laminar element.

[0021] Such aim and such objects are also achieved by way of a machine for coupling laminar elements, characterized in that it comprises:

[0022] - at least one first line for supplying a first continuous laminar sheet; - at least one second line for supplying a second continuous laminar sheet;

[0023] - at least one third line for supplying at least one continuous ribbon of thermally activateable adhesive substance;

[0024] - at least one first element configured for the deposition and juxtaposition of said at least one continuous ribbon on at least one face of said at least one first laminar sheet, forming at least one two-layer semifinished product;

[0025] - at least one burner, which is proximate to said at least one two-layer semi-finished product, which faces the surface comprising the continuous ribbon and is configured for the rapid heating thereof to the softening temperature;

[0026] - at least one second element configured for the deposition and juxtaposition of said at least one second laminar sheet on the surface comprising said at least one softened ribbon of said at least one semifinished product, forming at least one layered laminar element.

[0027] Further characteristics and advantages of the invention will become more apparent from the detailed description that follows of preferred, but not exclusive, embodiments of the method and of the machine for coupling laminar elements, which are illustrated by way of non-limiting example in the accompanying drawings wherein:

[0028] Figure 1 is a schematic cross-sectional side view, taken along a transverse plane, of a first embodiment of a machine for coupling laminar elements according to the invention;

[0029] Figure 2 is a schematic cross-sectional side view, taken along a transverse plane, of a second embodiment of a machine for coupling laminar elements according to the invention;

[0030] Figure 3 is a schematic cross-sectional side view, taken along a transverse plane, of a third embodiment of a machine for coupling laminar elements according to the invention.

[0031] With reference to the figures, the reference numeral 1 generally designates a machine for coupling laminar elements according to the invention, which is adapted to carry out the method according to the invention.

[0032] The method according to the invention is intended for the coupling of laminar elements constituted by at least one first laminar sheet A and at least one second laminar sheet B which are mutually superimposed.

[0033] The method according to the invention comprises a first step which entails depositing a predefined amount of a thermally activateable adhesive substance on a first face Ai of the first laminar sheet A.

[0034] A subsequent second step entails heating, for a predetermined time interval, the first face Ai of the first sheet A on which the adhesive substance is deposited, by means of a device of the type of a burner 2, for rapid heating of the adhesive substance.

[0035] Then it is necessary to execute a third step which entails juxtaposing a first face Bi of the second laminar sheet B against the first face Ai of the first sheet A on which the adhesive substance, activated as a result of the localized heating produced by the burner 2 (which causes a softening of the adhesive substance), is deposited.

[0036] The method according to the invention concludes with a fourth step which entails subjecting the first laminar sheet A and the second laminar sheet B (between which the adhesive substance, softened by the heating applied with the burner 2, is interposed) to mutual compression for their compaction, so defining a layered laminar element P.

[0037] In the method according to the invention, by virtue of the rapidity with which the burner 2 (which emits flames toward the thermally activateable adhesive substance) heats the adhesive substance, bringing it to softening temperature (i.e. activating its adhesive properties which will stably bond the first A and the second sheet B), it is possible to envisage high production speeds of the layered laminar element P: in particular we envisage carrying out the method according to the invention so as to obtain production speeds of the layered laminar element P higher than 12 meters per minute; preferably production speeds will be obtained that are higher than 20 meters per minute, and even more preferably it will be possible to achieve production speeds in the interval between 35 and 45 meters per minute. However, the possibility is not ruled out of achieving even higher speeds than 45 meters per minute.

[0038] It should be noted that, according to an embodiment of undoubted practical and applicative interest, the thermally activateable adhesive substance can advantageously be constituted by a continuous ribbon C of a type selected from a thermally activateable adhesive film, a thermally activateable adhesive mesh, a plurality of contiguous thermally activateable adhesive strips, and combinations thereof.

[0039] The advantage of this embodiment lies in the possibility of collecting all the raw materials in respective spools (a first spool which contains the first laminar sheet A, a second spool which contains the second laminar sheet B and a third spool which contains the ribbon C), so as to make it more convenient, including from a logistical point of view, to execute the method according to the invention and procure new raw materials when the materials in use are exhausted.

[0040] If the ribbon C is constituted by a plurality of contiguous thermally activateable adhesive strips, these can still be wound on a respective spool from which they will be unreeled, keeping them parallel so as to generate adhesive lines on the first face Ai of the first sheet A on which they will be juxtaposed.

[0041] The first step of depositing the thermally activateable adhesive substance on the first face Ai of the first sheet A therefore consists in laying the ribbon C on the first face Ai of the first sheet A.

[0042] It should further be noted that, advantageously, after the ribbon C is laid on the first face Ai of the first sheet A and prior to the second step of heating, there is a step of compressing the ribbon C on the first face Ai of the first sheet A. Such compression can be applied by forcing the semifinished product D (constituted by the first sheet A on which the ribbon C of thermally activateable adhesive substance is superimposed) onto the surface of a roller which, in addition to changing the advancement direction of the semi-finished product D, will be a placing that will guarantee an optimal juxtaposition of the ribbon C against the first face Ai of the first sheet A.

[0043] It is convenient to note that the semi-finished product D could also be obtained during a deferred (i.e. executed before the other steps, optionally executed in a separate industrial plant) first step of the method of depositing the adhesive substance.

[0044] In this manner, the subsequent steps would be executed using a semifinished product D, for example supplied in spools, which is constituted by a first sheet A comprising a layer of adhesive substance (in the technical jargon of the sector, such material could be described as a pre-adhesive-treated first sheet A).

[0045] It should further be noted that the continuous ribbon C can advantageously be made of a thermoplastic polymer selected from polyethylene terephthalate, polyamide, polyester, polyurethane, polyethylene, polypropylene, polyvinyl chloride, polylactate, and combinations thereof.

[0046] Of these polymers it should be noted that, for a plurality of applications, polyethylene terephthalate, polyamide, and polyurethane are most indicated.

[0047] It should be noted that for the polymers indicated, it is possible to use copolymers that comprise them, if necessary having strips C with predefined characteristics.

[0048] In any case, all the thermoplastic polymers listed above can be chosen from freshly synthesized polymers and polymers from recycling, and combinations of these types.

[0049] In detail, that is to say, each of the thermoplastic polymers comprised in the ribbon C can be fully constituted by freshly synthesized polymers, or fully constituted by recycled polymers, or be partially constituted by freshly synthesized polymers and partially by recycled polymers.

[0050] With particular reference to a particularly efficient version of the method according to the invention, it should be noted that the continuous ribbon C can profitably have a mass per unit area that is variable between 1 and 1000 g / m2, preferably between 5 and 500 g / m2, even more preferably between 10 and 100 g / m2. The mass per unit area of the ribbon C is chosen at the design stage of the layered element P to be produced, in order to give it the necessary technical and mechanical performance, and also the required appearance and texture.

[0051] It should further be noted that the at least one first sheet A and the at least one second sheet B have a mass per unit area that is variable between 5 and 5000 g / m2, preferably between 10 and 2500 g / m2, even more preferably between 25 and 1000 g / m2.

[0052] In this case too, the mass per unit area of the at least one first sheet A and of the at least one second sheet B are chosen at the design stage of the layered element P to be produced, in order to give it the necessary technical and mechanical performance, and also the required appearance and texture.

[0053] The at least one first sheet A and the at least one second sheet B are made of material selected from fabrics, microfiber, three-dimensional honeycomb fabrics, non-woven fabrics, imitation leather, foils comprising coagulated microfiber and foils comprising coated polymer fibers.

[0054] In particular, if the sheets A and B are constituted by fabrics, these fabrics can comprise fibers chosen from natural fibers, polymeric fibers, metallic fibers, ceramic fibers, mineral fibers, carbon fibers. They can be fabrics of the type selected from perpendicular yam fabrics, circular weave fabrics, flat weave fabrics.

[0055] If the sheets A and B are made of imitation leather, the latter will comprise at least one polymer selected from polyvinyl chloride, polyurethane, polyester and polyamide (and it may also be constituted by a combination of these polymers, both with each other and with other materials, which may be variously layered).

[0056] Among foils comprising coagulated polymeric microfiber, it is convenient to cite a non-woven fabric composed of coagulated polyester microfiber making up approximately 60%-80% and polyurethane for the remaining 20%-40%: among these materials there is the material known by the trade name Alcantara®. Among other types of foils comprising coagulated and / or coated polymeric fiber and / or microfiber, it is convenient to cite the material known by the trade name Dinamica®. The possibility is not ruled out of using other types of foils, comprising coagulated and / or coated polymeric fiber and / or microfiber, existing on the market and distinguished by different trade names.

[0057] The present invention also extends its protection to include a machine 1 for coupling laminar elements which comprises at least one first line 3 for supplying a first continuous laminar sheet A and at least one second line 4 for supplying a second continuous laminar sheet B.

[0058] The machine 1 according to the invention further comprises at least one third line 5 for supplying at least one continuous ribbon C of thermally activateable adhesive substance.

[0059] The machine 1 according to the invention further comprises at least one first element 6 configured for the deposition and juxtaposition of the at least one continuous ribbon C on at least one first face Ai of the at least one first laminar sheet A, forming at least one two-layer semi-finished product D.

[0060] The presence is further envisaged of at least one burner 2, proximate to the at least one semi-finished product D (constituted by two layers): the burner 2 faces toward the surface that comprises the continuous ribbon C of such semi-finished product D and is configured to rapidly heat the ribbon C to the softening temperature.

[0061] Lastly, the machine 1 comprises at least one second element 7 configured for the deposition and juxtaposition of the at least one second laminar sheet B on the surface comprising the at least one softened ribbon C of the at least one semi-finished product D, forming at least one layered laminar element P.

[0062] It should furthermore be noted that at least one component selected from the at least one first element 6 and the at least one second element 7 comprises at least one calendering unit for the transverse compression respectively of the semi-finished product D and of the layered laminar element P, to stabilize the characteristics thereof and ensure a perfect cohesion of the layers that constitute it (respectively, the ribbon C and the first sheet A and / or the second sheet B, the ribbon C and the first sheet A).

[0063] The at least one second element 7, configured for the deposition and juxtaposition of the at least one second laminar sheet B on the surface of the at least one semi-finished product D comprising the at least one softened ribbon C, is arranged downstream of the burner 2 and proximate thereto.

[0064] The burner 2 emits flames directed toward the surface of the semifinished product on which the at least one ribbon C is deposited (the flames directly striking the ribbon C or, more specifically, the adhesive substance deposited on the face Ai of the first sheet A), so bringing the latter to the respective softening temperature at which it becomes highly adhesive (and can also at least partially impregnate the sheets A and B with which it comes into contact).

[0065] The burner 2 can be fueled indifferently with liquefied petroleum gas (LPG), methane gas, or other fuels of any kind.

[0066] If it is necessary to increase or decrease the thermal power dispensed by the burner 2, it is possible to modify the flow rate of the fuel that feeds it. However, if, at the design stage, it is decided that a particularly high (or particularly low) thermal power is needed, it will be possible to use burners 2 of different dimensions which could comprise, for example, a different number of fuel dispensing nozzles (so as to adapt the breadth of the flame front that will strike the ribbon C and / or the thermally activateable adhesive substance to the specific requirements of the application to be implemented).

[0067] Advantageously the present invention solves the abovementioned problems, by providing a method for coupling laminar elements that can be applied substantially on any type of sheets A and B to be coupled.

[0068] Conveniently the coupling method according to the invention offers a high rate of productivity, in particular with a production speed higher than 12 meters per minute, more precisely even of the order of 35-45 meters per minute (although even higher speeds are not ruled out).

[0069] Advantageously, the coupling method according to the invention makes it possible to obtain layered laminar elements P (effectively constituted by layered composite materials) that are very stable and long-lasting over time.

[0070] Profitably, the coupling method according to the invention makes it possible to obtain layered laminar elements P (layered composite materials) of high quality, both in terms of aesthetics and in terms of performance and function.

[0071] Positively, the machine for coupling laminar elements according to the invention is adapted to couple any type of sheets A and B.

[0072] Conveniently the machine for coupling according to the invention offers contained space occupation.

[0073] Positively the method and the machine for coupling laminar elements according to the invention are easily and practically implemented and low cost: such characteristics render the method and the machine 1 according to the invention innovations that are certain to be safe in use.

[0074] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

[0075] In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be interchanged with other, different characteristics, existing in other embodiments.

[0076] In practice, the materials employed, as well as the dimensions, may be any according to requirements and to the state of the art.

[0077] The disclosures in Italian Patent Application No. 102024000025554 from which this application claims priority are incorporated herein by reference.

[0078] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

CLAIMS1. A method for coupling laminar elements which are constituted by at least one first laminar sheet (A) and at least one second laminar sheet (B) which are mutually superimposed, characterized in that it comprises the steps of:- depositing a predefined amount of a thermally activateable adhesive substance on a first face (Ai) of said first laminar sheet (A);- heating, for a predetermined time interval, said first face (Ai) of said first sheet (A) on which said adhesive substance is deposited, by means of a device of the type of a burner (2), for rapid heating of said adhesive substance;- juxtaposing a first face (B i) of said second laminar sheet (B) against said first face (Ai) of said first sheet (A) on which said adhesive substance, activated as a result of the localized heating produced by said burner (2), is deposited;- subjecting said first laminar sheet (A) and said second laminar sheet (B) to mutual compression for their compaction, so defining a layered laminar element (P).

2. The method according to claim 1, characterized in that said thermally activateable adhesive substance is a continuous ribbon (C) of a type selected from a thermally activateable adhesive film, a thermally activateable adhesive mesh, a plurality of contiguous thermally activateable adhesive strips, and combinations thereof, said step of depositing said thermally activateable adhesive substance on said first face (Ai) consisting in laying said ribbon (C) on said first face (Ai) of said first sheet (A).

3. The method according to claim 2, characterized in that, after laying said ribbon (C) on said first face (Ai) of said first sheet (A) and prior to said heating step, there is a step of compressing said ribbon (C) on said first face (Ai) of said first sheet (A).

4. The method according to claim 2, characterized in that saidcontinuous ribbon (C) is made of a thermoplastic polymer chosen from polyethylene terephthalate, polyamide, polyester, polyurethane, polyethylene, polypropylene, polyvinyl chloride, polylactate and combinations thereof, all the thermoplastic polymers in the list being chosen from freshly synthesized polymers and polymers from recycling and combinations of these types.

5. The method according to claim 2, characterized in that said continuous ribbon (C) has a mass per unit area that is variable between 1 and 1000 g / m2, preferably between 5 and 500 g / m2, even more preferably between 10 and 100 g / m2.

6. The method according to one or more of the preceding claims, characterized in that said at least one first sheet (A) and said at least one second sheet (B) have a mass per unit area that is variable between 5 and 5000 g / m2, preferably between 10 and 2500 g / m2, even more preferably between 25 and 1000 g / m2, and are made of a material chosen from:- fabrics, comprising fibers chosen from natural fibers, polymeric fibers, metallic fibers, ceramic fibers, mineral fibers, carbon fibers, of a type chosen from perpendicular yam fabrics, circular weave fabrics, flat weave fabrics,- microfiber,- three-dimensional honeycomb fabrics,- non-woven fabrics,- imitation leather comprising at least one polymer chosen from polyvinyl chloride, polyurethane, polyester, polyamide,- foils comprising coagulated polymeric microfiber,- foils comprising coated polymer fibers.

7. A machine for coupling laminar elements, characterized in that it comprises:- at least one first line (3) for supplying a first continuous laminar sheet (A);15- at least one second line (4) for supplying a second continuous laminar sheet (B);- at least one third line (5) for supplying at least one continuous ribbon (C) of thermally activateable adhesive substance;- at least one first element (6) configured for the deposition and juxtaposition of said at least one continuous ribbon (C) on at least one face (Ai) of said at least one first laminar sheet (A), forming at least one two-layer semi-finished product (D);- at least one burner (2), which is proximate to said at least one two-layer semi-finished product (D), which faces the surface comprising the continuous ribbon (C) and is configured for the rapid heating thereof to the softening temperature;- at least one second element (7) configured for the deposition and juxtaposition of said at least one second laminar sheet (B) on the surface of said at least one semi-finished product (D) comprising said at least one softened ribbon (C), forming at least one layered laminar element (P).

8. The machine according to one or more of the preceding claims, characterized in that at least one component selected from said at least one first element (6) and said at least one second element (7) comprises at least one calendering unit for the transverse compression of said semi-finished product (D) and said layered laminar element (P) respectively.

9. The machine according to one or more of the preceding claims, characterized in that said at least one second element (7), configured for the deposition and juxtaposition of said at least one second laminar sheet (B) on the surface of said at least one semi-finished product (D) comprising said at least one softened ribbon (C), is arranged downstream of said burner (2) and proximate thereto.

10. The machine according to one or more of the preceding claims, characterized in that said burner (2) emits flames directed toward the surface of said semi-finished product (D) on which said at least one ribbon (C) is16 deposited.

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