STATION FOR PLASMA PRE-TREATMENT OF LEATHER, AS WELL AS SYSTEM FOR PROCESSING LEATHER COMPRISING SUCH STATION AND METHOD FOR PROCESSING THEREOF

Abstract

 A station for the pre-treatment of at least one animal leather or leather of animal origin or at least partially synthetic leather (P), the station being suitable to be used in a system (I) for processing the at least one leather (P) and comprising a station (SV) for the diffuse coating of the at least one leather (P). The pre-treatment station comprises an inlet (IPT) and an outlet (UPT) for the leather (P) and means (20) for advancing the leather (P) interposed between the inlet (IPT) and the outlet (UPT) of the pre-treatment station (PT). In this manner the pre-treatment of the leather (P) and the advancement of the latter from the inlet (IPT) of the pre-treatment station (PT) towards the outlet (UPT) of the latter is allowed. The pre-treatment station (PT) further includes plasma generation means (10) which include at least one torch (12) at least partially mutually facing the advancement means (20) suitably configured and sized to act on at least one portion of the leather (P) to be pre-treated.

Description

Technical field

[0001] The present invention generally relates to the technical field of methods for processing animal leather or leather of animal origin or at least partially synthetic leather and in particular it relates to processes subsequent to tanning, for example in refining processes. Therefore, the present invention relates to a station for the plasma pre-treatment of leather, as well as a system for processing leather which includes such station and a method for processing the latter.

Definitions

[0002] In the present document, the expression "hide" or "leather" is used to indicate any layer, whether it be grain, crust or sub-crust, of the leather of an animal, in particular of a bovine, but also of sheep/goats, exotic, fur, wild animals or others.

[0003] In particular, the expression "a leather" or "the leather" is used to indicate at least one part of the leather of a single animal, which may therefore be of any shape. For example, the leather may be whole leather, half leather, shoulders, hunch, back, hips, rear or front parts of the body.

[0004] The expression "animal leather or leather of animal origin" is used to indicate the so-called "genuine leather", the so-called "leatherette" or "faux leather" or other similar composite products containing animal leather.

[0005] In the present document, the expression "diffuse coating" is used to indicate deposition of one or more layers of dye coating in a diffused and homogeneous manner on the leather, by spraying using appropriate nozzles or guns or using roller machines, spreading machines or buffer machines.

[0006] In the present document, the expression "preparation" or derivatives thereof is used to indicate the provision of an element of interest to a process step of interest, thus including any preventive treatment aimed at the optimal execution of the step of interest, from simple collection and possible storage to heat and/or chemical and/or physical pre-treatments and the like.

[0007] In the present document, the expression "pre-treatment" or derivatives relating to an animal leather or leather of animal origin or at least partially synthetic leather, is used to indicate the preliminary treatment carried out thereon before the subsequent and more important processing stages are carried out.

[0008] In the present document, the expression "torch" or the like, is used to indicate a device which generates a direct flow of plasma from a nozzle following the application of an appropriate potential difference between two electrodes.

[0009] In the present document, the expression "contact angle" is used to indicate the thermodynamic quantity to determine the wettability of a surface, defined by the angle comprised between the direction of the solid-liquid tension and the direction of the liquidvapour tension, tangent to the outer surface of the drop, with the vertex in the liquid-solid-vapour three-phase point, according to the UNI EN 828:2013 standard.

[0010] In the present document, the expression "cold plasma" or derivatives is used to indicate a type of plasma in which the electrons are not in thermodynamic equilibrium with the other species, given that they are characterised by a much higher temperature with respect to that of the heavier species (ions and neutral species). In these conditions, the energy of the electrons may be described by using probability distribution functions, such as for example Maxwell or Druyvesteyn distributions.

State of the Art

[0011] Plants for processing leather which include - in succession - several stations, including a station for the diffuse coating animal leather, are known.

[0012] Therefore, the leather is loaded at the inlet of the system and transported using conveyors in series which move it along the subsequent processing stations.

[0013] The waterproof characteristic of leather complicates the coating thereof, causing the creation of drops of paint thereon which tend to create stains with ensuing aesthetic defect.

[0014] In addition, the impermeability of leather together with the diffuse coating treatment lead to a surface deposition of paint, entailing a high use of the latter and a consistent stationing of the leather in the coating station given that there are required multiple passes on the same leather portion in order to create a complete and uniform spreading thereof.

[0015] Therefore, this results in a high waste of time and resources.

Summary of the invention

[0016] An object of the present invention is to at least partly overcome the drawbacks illustrated above by providing a particularly functional station for the pre-treatment of leather.

[0017] A further object of the present invention is to provide a station which allows a coating of the leather with low amount of paint.

[0018] Another object of the present invention is to provide a station which allows a coating of the leather with significant saving of time.

[0019] Another object of the present invention is to provide a system for processing leather that is highly functional.

[0020] Another object of the invention is to provide a method for processing leather that is particularly quick.

[0021] These and other objects which will be more apparent hereinafter, are attained by a station and/or by a system and/or by a method as described, illustrated and/or claimed herein.

[0022] The dependent claims define advantageous embodiments of the invention.

Brief description of the drawings

[0023] Further characteristics and advantages of the invention will be more apparent in light of the detailed description of a preferred but non-exclusive embodiment of the invention, illustrated by way of non-limiting example with reference to the attached drawings, wherein:

FIG. 1 is a front schematic view of the system I;

FIG. 2 is a top schematic view of the system I;

FIG. 3 is a top schematic view of the apparatus 1;

FIG. 4 is an axonometric schematic view of the apparatus 1;

FIG. 5 is a front schematic view of the apparatus 1.

Detailed description of some preferred embodiments

[0024] With reference to the attached figures, herein described is a system I for carrying out one or more processing operations on the leather P. The system I may therefore comprise one or more processing stations for carrying out one or more processing operations subsequent to tanning, such as for example fleshing , breaking, shaving, dyeing, greasing, desiccation (or drying), possibly staking and/or nailing, refining, stretching, pressing and/or measuring.

[0025] In particular, the system I may have an inlet IN for the leather P to be processed and an outlet OUT for the processed leather P.

[0026] In a per se known manner, the leather P may be moved between consecutive stations by means of appropriate advancement means.

[0027] Advantageously, the advancement means may include one or more conveyors in series and, consecutive thereto, means for unloading and/or loading the leather, for example one or more rollers arranged between a pair of stations.

[0028] The conveyors may for example be wire or slat conveyors or any other appropriate technology, known in the industry.

[0029] In this specific case, the advancement means may include all means which allow to move and advance the leather P between the inlet of a first station and the inlet of a second and subsequent station.

[0030] Basically, in each station, the advancement means may be defined by one or more conveyors in series and the consecutive rollers which allow the unloading and the subsequent loading of the leather towards the inlet of the subsequent station.

[0031] Or, as particularly shown in FIG. 1, the advancement means may be defined by a single conveyor movable between consecutive stations.

[0032] Preferably, the system I may include a pre-treatment station PT of the leather P having an inlet IPT and an outlet UPT.

[0033] Preferably, the inlet IPT may correspond with the inlet IN of the system I.

[0034] In addition, consecutively to the station PT, the system I may include a diffuse coating station SV with an inlet ISV consecutive to the outlet UPT and an outlet USV.

[0035] Preferably, the diffuse coating station SV may include a plurality of nozzles rotating around an axis Z perpendicular to the plane defined by the conveyors and cyclically passing through the surface of the leather P.

[0036] It is therefore clear that the side of the leather P whose surface faces the nozzles may be coated.

[0037] Furthermore, it is clear that the system I may include a station PA for curing the paint consecutive to the diffuse coating station SV and other potential processing stations without departing from the scope of protection of the attached claims.

[0038] In particular, the pre-treatment station PT may include a conveyor 21 of the type described above, which may extend between the inlet IPT and the outlet UPT of the station PT.

[0039] The conveyor 21 may define an axis Y which may coincide with the advancement direction thereof.

[0040] This will allow to move the leather P between the inlet IPT and the outlet UPT of the station PT to allow the pre-treatment thereof.

[0041] The conveyor 21 may have a width Ia21 along a direction perpendicular to the axis Y, for example measuring 70 - 380 cm.

[0042] Furthermore, between the inlet UPT and the outlet ISV there may be present special rollers to allow the unloading of the pre-treated leather P and the loading thereof towards the coating station SV.

[0043] In particular, the conveyor 21 and the rollers may define means 20 for advancing the leather P.

[0044] However, it is clear that the advancement means 20 may be defined solely by the conveyor 21 without departing from the scope of protection of the attached claims.

[0045] Furthermore, it is clear that the advancement means 20 may advance along the axis Y so as to move the leather P along a direction defined by the latter.

[0046] Preferably, the station PT may include plasma generation means 10.

[0047] There may be arranged above the conveyor 21 so as to at least partially face the advancement means 20, for example should the latter also include possible subsequent loading/unloading means.

[0048] Specifically, the conveyor 21 may include a progressive planar advancement portion 210 of the leather P and the plasma generation means 10 may be positioned above the latter.

[0049] It is therefore clear that the progressive planar advancement portion 210 may be that conveyor portion 21 which may be in contact with the leather P so as to support it and allow the advancement thereof.

[0050] Generally, the plasma generation means 10 may include one or more torches 12 which generate a laminar plasma discharge along an axis X incident with respect to the axis Y.

[0051] Preferably, the axes X and Y may be perpendicular to each other.

[0052] Such plasma laminar discharge may therefore act on at least one portion of the leather P.

[0053] This will allow to pre-treat the leather P through a single processing cycle, that is through a single pass under the one or more torches 12.

[0054] As a result, this will allow to massively reduce the processing times thereof.

[0055] In addition, the one or more torches 12 may be integrally joined with the support structure of the system I so as to remain fixed in particular during the pre-treatment of the leather P.

[0056] However, the one or more torches 12 may be movable along the axis Y without departing from the scope of protection of the attached claims.

[0057] According to a first embodiment, the plasma generation means 10 may include a torch 12 with a pair of electrodes 11 facing each other through which there will flow the gas selected for generating plasma, in a per se known manner.

[0058] Furthermore, the electrodes 11 may both face the conveyor 21, even more specifically, the progressive planar advancement portion 210, on the same side.

[0059] In other words, both the electrodes 11 may be positioned above the conveyor 21, as well as the progressive planar advancement portion 210.

[0060] Preferably, the electrodes 11 may be metallic and flat and they may each have a length Iu11 measured along the axis X measuring 60 - 100 cm, preferably 70 - 90 cm.

[0061] Advantageously, the length Iu11 may be equal to or greater than the width Ia21 so that the plasma discharge extends over the entire width of the conveyor 21.

[0062] For example, should the axes Y and X not be perpendicular to each other, the length Iu11 may be greater than the width Ia21, while should the axes Y and X be perpendicular to each other, the length Iu11 may be equal to the width Ia21.

[0063] This will allow to act over the entire surface of the leather P, given that the laminar plasma discharge may have a length corresponding to the length Iu11.

[0064] To this end, the distance between the outlet of the torch 12 and the conveyor 21 may have a size d for example measuring 1-20 mm, more preferably 5-15 mm, so as to allow to obtain a matching length between the laminar plasma discharge and the length Iu11, in a per se known manner.

[0065] According to a second embodiment, the plasma generation means 10 may include a plurality of torches 12, each with a pair of electrodes 11 facing each other, positioned consecutively in series along the axis X.

[0066] Even in this case, both the electrodes 11 of each torch 12 may be facing the conveyor 21, as well as the progressive planar advancement portion 210, on the same side.

[0067] Therefore, both the electrodes 11 of each torch 12 may be positioned above the conveyor 21, as well as above the progressive planar advancement portion 210.

[0068] Preferably, the electrodes 11 may be metallic and flat and they may each have a length Iu11 measured along the axis X measuring 60 - 100 cm, preferably 70 - 90 cm.

[0069] Therefore, the succession of electrodes 11 of the plurality of torches 12 may have an overall length IuS11 along the axis X with size equal to or greater than the width Ia21, so that the plasma discharge extends over the entire width of the conveyor 21 to act on the entire surface of the leather P.

[0070] As described above, should the axes Y and X not be perpendicular to each other, the length IuS11 may be greater than the width Ia21, while should the axes Y and X be perpendicular to each other, the length IuS11 may be equal to the width Ia21.

[0071] For example, the conveyor 21 may have a width Ia21 equal to 380 cm and the plasma generation means 10 may include a series of several torches 12 each with a pair of electrodes 11 having length Iu11 such that the overall length IuS11 is equal to 380 cm.

[0072] It is clear that the laminar plasma discharge may have a length corresponding to the length IuS11.

[0073] To this end, the distance between the outlet of the torches 12 and the conveyor 21 may measure d for example 1-20 mm, more preferably 5-15 mm, so as to allow a matching length between the laminar plasma discharge and the length IuS11, in a per se known manner.

[0074] According to a further preferred but not exclusive embodiment, the plasma generation means 10 may include a succession of torches 12 or a series of torches 12 positioned parallel along the axis Y.

[0075] This will allow to reduce the power density imparted on each torch 12 to prevent the formation of arcs.

[0076] According to a particular aspect of the invention, the pre-treatment station PT may include an apparatus 1 which comprises - in a single structure - the plasma generation means 10 and the advancement means 20, as particularly shown in FIGS. 3, 4 and 5.

[0077] Preferably, the plasma may be generated by applying - to the electrodes 11 - a power density amounting to about 30 - 250 W/cm, more preferably amounting to 100 - 200 W/cm.

[0078] On the other hand, the advancement means 20, specifically the conveyor 21, may have a speed of 1-12 m/min.

[0079] This will allow to obtain cold plasma at atmospheric pressure.

[0080] In addition, such power density and advancement speed values may allow to act on the leather P so as to create a temporary permeability on the portion thereof treated with the plasma to optimise the subsequent coating in the station SV.

[0081] As a matter of fact, the plasma pre-treatment will allow to increase the penetration and the absorption of the paint, with an ensuing reduced amount of paint required and lesser stationing in the coating station so as to obtain a uniform spreading on the entire surface of the leather P.

[0082] According to a preferred but not exclusive embodiment, although the selected gas may be compressed air so as to reduce costs, plasma may be generated starting from any other gas without departing from the scope of protection of the attached claims.

[0083] Specifically, should the plasma be generated starting from compressed air, with the aforementioned power density values, the contact angle measured on the pre-treated and coated leather P at the outlet USV may be 35° - 75°, more preferably 40° - 65° according to the UNI EN 828:2013 standard and any updates of such regulation subsequent to the date of filing of the present document.

[0084] Preferably, the coating station SV may include advancement means 30 which include a conveyor 31.

[0085] Specifically, the advancement means 20 and 30 may be consecutive with respect to each other so as to allow a continuous advancement of the leather P, as well as a continuous processing of the latter.

[0086] This will allow to reduce the processing times of the leather P.

[0087] According to a preferred but not exclusive embodiment, as shown in FIG. 1, the conveyor 21 and the conveyor 31 may define a single conveyor 2131, should there not be interposed means for loading and/or unloading the leather in particular between the pre-treatment station PT and the coating station SV.

[0088] From an operative point of view, after an appropriate preparation of the leather P, the latter may be loaded at the inlet IN of the system I, that is - in this case - at the inlet IPT of the pre-treatment station PT.

[0089] The leather P may also be moved between the inlet IPT and the outlet OUT passing through the pre-treatment station PT and the coating station SV so as to allow the plasma treatment and the subsequent coating.

[0090] In addition, the coated leather P may pass through the curing station PA for fixing the paint and through possible subsequent additional processing stations.

[0091] According to a further aspect of the invention, there may be per se considered a pre-treatment station PT as described above and which can be used in any system I as described above, therefore comprising a diffuse coating station SV consecutive to the pre-treatment station PT.

[0092] Therefore, it is clear that a such pre-treatment station PT, a such system I and a method as described may allow to create a temporary permeability to the leather to be coated so as to reduce the amount of paint required, as well as the overall processing thereof.

[0093] The present invention may include various parts and/or similar or identical elements. Unless otherwise specified, similar or identical parts and/or elements will be indicated using a single reference number, it being clear that the described technical characteristics are common to all similar or identical parts and/or elements.

[0094] The invention is susceptible to numerous modifications and variants, all falling within the scope of protection of the attached claims. All details can be replaced by other technically equivalent elements, and the materials can be different depending on the needs, without departing from the scope of protection of the invention defined by the attached claims.

Claims

1. A station for the pre-treatment of at least one animal leather or leather of animal origin or at least partially synthetic leather (P), the station being suitable to be used in a system (I) for processing at least one leather (P) comprising a diffuse coating station (SV) of the at least one leather (P) with first means (30) for advancing the latter and a plurality of coating nozzles rotating around a first axis (Z) substantially perpendicular to said first advancement means (30) to cyclically dispense paint on at least one portion of the surface of the at least one leather (P) mutually facing the nozzles, the pre-treatment station comprising:

- an inlet (IPT) for the at least one leather (P) to be pre-treated and an outlet (UPT) for the at least one pre-treated leather (P);

- second advancement means (20) of the at least one leather (P) at least interposed between the inlet (IPT) and the outlet (UPT) of the pre-treatment station (PT) to allow the pre-treatment of the at least one leather (P) and promote the advancement of the latter from the inlet (IPT) of the pre-treatment station (PT) towards the outlet (UPT) of the latter;

- plasma generation means (10) including at least one torch (12) with at least one pair of mutually facing electrodes (11), said at least one torch (12) mutually at least partially facing said second advancement means (20), the plasma generation means (10) being suitably configured and sized to act on at least one portion of said at least one leather (P) to be pre-treated.

2. Station according to claim 1, wherein said second advancement means (20) are configured to advance longitudinally along a second axis (Y), said second advancement means (20) including at least one conveyor (21) having a predetermined width (Ia21) along a direction perpendicular to said second axis (Y), said plasma generation means(10) being configured to generate a substantially laminar plasma discharge along a third axis (X) incident with respect to said second axis (Y), preferably perpendicular.

3. Station according to the preceding claim, wherein said pair of electrodes (11) are substantially planar and have a predetermined length (Iu11) along a direction parallel to said third axis (X) substantially equal to or greater than the width (Ia21) of said at least one conveyor (21) to generate said laminar discharge extending along the entire width (Ia21) of the latter.

4. Station according to claim 2, wherein said plasma generation means (10) comprise a plurality of said at least one torch (12), said at least one pair of electrodes (11) of each of the latter being substantially planar, the torches (12) being arranged consecutively in series along said third axis (X), the succession of the pairs of electrodes (11) of said plurality of electrodes (12) having a predetermined overall length (IuS11) along a direction parallel to said third axis (X) substantially equal to or greater than the width (Ia21) of said at least one conveyor (21) to generate said laminar discharge extending along the entire width (Ia21) of the latter.

5. Station according to claim 3 or 4, wherein said plasma generation means (10) further comprise a succession of said at least one torch (12) or of said plurality of said at least one torch (12) positioned parallel along said second axis (Y).

6. Station according to any one of claims 2 to the preceding, wherein said plasma generation means (10) are positioned above said at least one conveyor (21).

7. Station according to the preceding claim, wherein both said electrodes (11) of said at least one torch (12) are mutually facing said at least one conveyor (21) on the same side.

8. Station according to claim 6 or 7, wherein the outlet of said at least one torch (12) and said at least one conveyor (21) have a mutual predetermined distance (d) measuring 1-20 mm, more preferably measuring 5-15 mm.

9. Station according to any one of the preceding claims, wherein the power density absorbed by said at least one torch (12) of said plasma generation means (10) is about 30 - 250 W/cm, more preferably 100 - 200 W/cm, said advancement means (20) advancing at a speed of 1-12 m/min.

10. Station according to the preceding claim, wherein said plasma generation means (10) generate cold plasma at atmospheric pressure.

11. Station according to claim 9 or 10, wherein the plasma is generated starting from compressed air, the contact angle measured on the at least one pre-treated and coated leather (P) measuring about 35° - 75°, more preferably 40° - 65° according to the UNI EN 828:2013 standard.

12. A system for processing at least one animal leather or leather of animal origin or at least partially synthetic leather (P), having an inlet (IN) for the at least one leather (P) to be processed and an outlet (OUT) for the at least one processed leather (P), comprising in series:

- a station (PT) for the pre-treatment of the at least one leather (P) according to one or more of claims 1 to 11;

- a station (SV) for the diffuse coating of a pre-treated leather (P) having an inlet (ISV) consecutive to the outlet (UPT) of the pre-treatment station (PT);

wherein said diffuse coating station (SV) includes first advancement means (30) at the inlet (ISV) of the latter, said first advancement means (30) being mutually consecutive to said second advancement means (20) so as to allow the continuous processing of the at least one leather (P); and

wherein said diffuse coating station (SV) includes a plurality of coating nozzles rotating around a first axis (Z) substantially perpendicular to the plane defined by said first advancement means (30) so as to cyclically dispense paint on at least one portion of the surface of the at least one leather (P) mutually facing the nozzles.

13. A method for processing at least one animal leather or leather of animal origin or at least partially synthetic leather (P) through a system according to the preceding claim, consecutively comprising the steps of:

- preparation of the at least one leather (P) to be processed;

- pre-treatment of the at least one leather (P) to be processed with plasma in said pre-treatment station (PT);

- diffuse coating of the leather (P) in said diffuse coating station (SV).

Drawing