WO2022175884A1

WO2022175884A1 - Reconditioning process and apparatus of release paper

Info

Publication number: WO2022175884A1
Application number: PCT/IB2022/051462
Authority: WO
Inventors: Andrea Orlandi; Matteo SIMONI; Lorenzo SIMONI
Original assignee: Barnini S.R.L.
Priority date: 2021-02-18
Filing date: 2022-02-18
Publication date: 2022-08-25
Also published as: EP4294983A1; IT202100003779A1

Abstract

The present invention relates to a process and to an apparatus for cleaning the so-called "release paper" used in the field of processes for ennobling (natural or synthetic) leathers, (natural or synthetic) fabrics or however all processes in which the use of the release paper is provided.

Description

RECONDITIONING PROCESS AND APPARATUS OF RELEASE PAPER

DESCRIPTION The present invention relates to a process ana an apparatus for the cleaning of the so-called “release paper” used in the field of processes for ennobling (natural or synthetic) leathers, (natural or synthetic) fabrics or however all processes in which the use of the release paper is provided. Background

In the present description reference will be made, even if by pure way of example, mainly to the field of the treatment of (natural or synthetic) leathers.

The process for ennobling leathers is well known and thus it will not herein be described in details. In general terms, this type of process provides the application of an ennobling layer on a typical laminar, natural, textile or synthetic support.

Typically, the ennobling layer consists of a polymeric film, preferably the polymer is a polyurethane.

For the application of the ennobling layer the use of the so-called release paper is provided which, for example, can have an embossed surface in order to make that the final product then reproduces the appearance of a natural leather, or however has the wished decoration. The ennobling layer is applied on the release paper, which is then approached to the laminar support.

The whole set is treated thermically to allow drying the components. The paper is separated from the support and the ennobling layer remains adhered to the laminar support, by reproducing the appearance of a natural product, or however by exposing the wished decoration.

With the purpose of being able to reuse the release paper several times, its cleaning is necessary to remove the residues of ennobling product and then to make it ready for a new processing cycle. Currently, the removal of the residues from the just used release paper is substantially performed mechanically.

In particular, the most common solution consists in making to adhere adhesive tape onto the face to be cleaned of the release paper and subsequently to remove such adhesive tape which brings along most residues existing on the release paper.

However, such method has some important disadvantages.

First of all, the used adhesive tape has to be replaced whenever it is used up, with consequent increase in process management costs.

The use of this method then involves in the industrial environment in which it is performed a considerable acoustic pollution which imposes on the workers the use of specific safety devices.

Moreover, the used adhesive tape represents an enormous problem at environmental level, since it is classified as special waste which has to be disposed of suitably in order not to cause damage to the environment due to the substances which are present on its surface.

At last, the cleaning of the paper performed with this method sometimes is not accurate, part of residues remaining on the paper itself can invalidate the qualities of the procedures connected to its subsequent use.

Other known solutions in the patent literature, and which have never been applied practically, are the solutions described for example in JP2009291690, JP2002265665, JP2004363140, JP2004169005 and CN110435044, which provide the full immersion of the continuous belts of release paper with the purpose of wholly dissolving the residues. Said solutions have the disadvantage of an excessive wetting of belt and then of making rips and tears of the same to occur during processing, even due to the tension thereto these belts are subjected during their sliding.

Technical problem solved by the invention

The object of the present invention is to solve the problems left unsolved by the known art, by providing a process for reconditioning the release paper in form of continuous belt as defined in the independent claim 1. The present invention further relates to an apparatus for reconditioning the release paper in form of continuous belt as defined in claim 12.

Additional features of the present invention are defined in the corresponding depending claims.

The present invention involves some important advantages.

First of all, the invention avoids the use of a disposable adhesive tape reel which can be used only once and which afterwards has to be disposed of, with relative huge costs both for the supply and for the disposal. In fact, the adhesive tape contaminated by the residues represents a special waste, the disposal thereof however involves an impact of environmental nature.

Moreover, the present invention avoids the problem of the noise caused by the detachment of the adhesive tape, which causes discomfort to the operators and requires to adopt soundproofing systems to reduce acoustic pollution.

Moreover, an apparatus according to the invention has considerably reduced overall dimensions with respect to the known art and, above all, a high structural simplicity, with consequent advantages in terms of maintenance.

Other advantages, together with the features and use modes of the present invention, will result evident from the following detailed description of preferred embodiments thereof, shown by way of example and not for limitative purpose.

Brief description of figures

Hereinafter in this description reference will be made to the drawings shown in the figures, wherein:

• figure 1 is a reconditioning plant of known art;

• figure 2 is a schematic representation of an apparatus according to a first embodiment of an apparatus according to the present invention;

• figure 3 is a schematic representation of an apparatus according to a second embodiment of an apparatus according to the present invention;

• figure 4 is a schematic representation of an apparatus according to a third possible embodiment of an apparatus according to the present invention, • figure 5 is a schematic representation of an apparatus according to an additional possible embodiment of an apparatus according to the present invention, and

• figure 6 is an overall view of an apparatus according to the embodiment schematized in figure 4.

Detailed description of preferred embodiments

The present invention will be described hereinafter by making reference to the above-mentioned figures.

In particular, figure 1 shows, by way of example, a plant 1 of known art for cleaning the release paper.

In particular, as it can be seen in figure 1 , the release paper 5 is supplied through a reel 4 and directed towards the plant for treatment and coupling to the support, as already described.

After having been separated from the support, the release paper 5 enters the cleaning plant 1, dragged from a carpet 7, moved by a roller 8.

At an adhesion area 12, the paper 5 comes in contact with an adhesive tape 6 which is supplied by means of a reel 11.

A traction roller 9 eases the sliding of the release paper 5.

The adhesion between adhesive tape 6 and release paper 5 in the adhesion area 12, makes that the residues existing on the release paper are transferred to the adhesive tape 6.

At the same time, the adhesive tape 6 is drawn towards a recovery reel 13 on which it is wound.

The release paper 5, without residues, is re-wound on a secondary reel 10 in order to be re-used in a new cycle, whereas the recovery reel 13 of the adhesive tape is intended to be disposed of.

The cleaning process the present invention relates to, differently from the known art, does not require the use of disposable adhesive tape. Differently, its operating principle is based upon the use of a solution which is distributed on the release paper, which is in form of continuous belt, with the purpose of softening and breaking down the paint and/or other residues existing on the same after use.

Then, according to the present invention, a process for reconditioning the release paper, for removing the residues from its surface, is provided, comprising at least a step of applying a solvent solution on the surface of the release paper to be cleaned.

For the purposes of the present invention, under solvent solution a solution is to be meant having solvent properties against the polymeric film used as ennobling film.

Such solvent solution then will be selected, each time, by the person skilled in the art and according to the known art, depending upon the particular ennobling polymeric film used in the process.

Advantageously such solvent solution can be a polar solution.

Preferably such polar solution comprises an alcohol, a ketone, water or a combination thereof.

Preferably the alcohol is ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, tert-butyl alcohol, more preferably ethyl alcohol.

Preferably the ketone is acetone, butanone, methylisobutylketone.

More preferably such solvent solution is a hydroalcoholic solution or an aqueous solution comprising ethyl alcohol, preferably in a concentration from 30% to 95%, still more preferably in a concentration from 50% to 90%.

In a still additional preferred embodiment such solvent solution consists exclusively of absolute ethyl alcohol.

Moreover, it is to be meant that several steps can even be provided wherein a solvent solution is placed in contact with the surface of the release paper which has to be cleaned from residues.

Advantageously, a residence time of the solution on the surface to be cleaned can be provided. This residence time for example can be obtained by adjusting the transit speed of the paper in form of continuous belt in the apparatus used for the reconditioning of the release paper. The slower the transit speed is, the longer the residence time will be.

According to a preferred embodiment, the process can further include a step of removing the residues, performed through a cleaning mechanical action, subsequently to the application of the solvent solution. The mechanical action could be exerted according to any mode selected among the already known ones, for example through a spatula approached to the surface, or through a rotating brush, preferably counterrotating with respect to the feeding direction of the release paper.

It is to be meant that other solutions of mechanical nature could be adopted, including even solutions providing for example the use of jets of possibly compressed air, directed towards the surface of the release paper to be cleaned.

Alternatively or additionally to the already described ones, other solutions could even be provided, for example a mechanism subjecting the release paper to vibration.

Moreover, it is to be meant that several mechanical cleaning steps can be provided, in which different techniques are used.

Moreover, according to some embodiments of the present invention, it is possible to provide one or more drying steps. A drying step preceding the mechanical action for removing the residues would result to be an advantage for such mechanical action. A drying step subsequent to the removal mechanical action would allow to be able to rewind the well dried reconditioned release paper in a new reel, ready for subsequent reuses.

According to other embodiments of the present invention, one or more suction steps can advantageously be provided.

A suction step can be provided for sucking the vapours released by the solvent solution, with the purpose of not polluting the surrounding air, above all for the operators’ welfare. To this purpose then a step for filtering the sucked elements can be provided. A sucking step can be provided, additionally or alternatively to what already described, for the suction of a light fraction of the residues separated from the release paper during the mechanical cleaning action. In this case a filtering step would allow the collection and disposal of the light fraction of residues.

A process as the already described one can advantageously be implemented in an apparatus for the reconditioning of release paper in form of continuous belt. Such apparatus then will include least a station for applying a solvent solution on the surface of the release paper.

According to the present invention, possible embodiments of an apparatus of this type are shown, schematically, in figures 2 to 5.

In particular, figure 2 illustrates a first possible embodiment of an apparatus 20 for the removal of residues from a surface 5’ of the release paper 5.

The apparatus 20 comprises a station 21 for applying a solvent solution only on the surface 5’ of the release paper 5; a mechanical station 31 for cleaning the residues from said surface 5’ of the release paper 5; and means for feeding the release paper 5 along a feeding direction A.

According to such first embodiment, the application station 21 comprises a roller 22, arranged so as to be in contact with the surface 5’ of the release paper in form of continuous belt 5 during the transit of the paper itself along the feeding direction A.

According to the invention, the roller 22 allows to apply the solvent solution on only one surface of the release paper and, preferably, it is a motorized roller having a core made of steel and a rubberized external surface.

It is contained in a tank 25 suitable for containing the solvent solution 26. The roller 22 then, during use of the apparatus, is partially dipped in the solvent solution 26.

It is preferably engraved and then has surface engraving keeping a predetermined amount of solution which is then transferred by contact to the paper.

The surface engraving allows to control in a very accurate way the amount of solvent which has to be applied to the paper surface and to guarantee that the same is uniformly distributed along its whole section. According to additional embodiments of the present invention, as shown in figures 3 to 5, the application station 21 comprises a pair of rollers 22, 23. The roller 22 is as described in relation to the first embodiment, whereas the roller 23 is a contrast idle roller.

The rollers 22 and 23 are arranged so that the release paper 5 can transit therebetween along the feeding direction A.

The application of the solvent solution is eased by the contrast idle roller 23, in contact with the opposite surface of the paper 5.

Said contrast idle roller 23 in fact determines even a better penetration of the solvent along the section of the surface 5’ of the paper belt thanks to the compression effect exerted thereby on said belt by contrast with the roller 22.

According a possible embodiment, the application station 21 further comprises a doctor blade 24 for adjusting the amount of solvent solution applied to the surface 5’ of the release paper 5 and for removing the excess thereof, to avoid moistening excessively the paper.

Moreover, it is to be meant that even several stations for applying solvent solution can be provided, each one using even a different solvent solution.

The mechanical cleaning station 31, according to the preferred embodiment of the invention, comprises a rotating brush 32 rotatably mounted on a rotation axis R, arranged to be able to rotate in contact with the surface 5’ of the release paper 5.

As it can be seen in figure 6, the rotating brush 32 can advantageously be enclosed in a carter, with the advantage of not dispersing excessively in the environment the residues separated from the release paper. The rotating brush preferably, can provide bristles made of nylon so as not to be excessively aggressive on the paper and to ruin the surface thereof.

Advantageously the rotating brush 32 is motorized, so as to be able to control its rotation in terms both of speed and rotation direction.

Preferably, the brush is made to counter-rotate as shown by the arrow in figure 2, then in opposite direction with respect to the feeding direction A of the paper 5 in the apparatus. In this way the cleaning effect of the brush on the surface of the paper is improved.

Advantageously, it can be provided that the mechanical cleaning station 31 further comprises means for translating the rotation axis R of the rotating brush 32 along an action direction M substantially orthogonal to the feeding direction A.

In this way, it is allowed to approach or move away the rotating brush 32 from the surface 5’ of the release paper 5, with the purpose of increasing or decreasing the pressure of the bristles of the rotating brush 32 on the surface 5’ of the release paper 5, being able in case to avoid the contact between brush and paper. The more the brush is approached to the surface 5’ of the paper, the more the exerted pressure will be, then the better the cleaning action of the brush itself will be.

The translation means advantageously can be actuated by means of actuators of pneumatic type. Alternatively, actuators of other nature, for example electric, hydraulic, etc. actuators, can be provided.

Advantageously, according to some embodiments, a contrast device 33 can be provided, indeed placed in contrast with the action of the rotating brush 32, on the opposite side of the release paper 5.

For example, in the embodiment schematized in figure 2, the contrast device 31 comprises one or more pushing rollers 34, preferably two pushing rollers 34. Preferably, the pushing rollers 34 are idle mounted.

It is to be meant that even only one pushing roller can be provided, in contrast with the brush action.

Alternatively or additionally, the contrast device 33 can include, as for example shown in the embodiment schematized in figure 4, a sheet 35, preferably adjustable in height.

The function of such sheet 35 however is to exert an action contrasting the rotating brush 32, with the purpose of improving the cleaning mechanical action of the same on the surface 5’ of the release paper.

At the output of the cleaning and conditioning apparatus 20, the release paper belt continues its path towards a station for winding in reel to be re-used in the subsequent processing. It is to be meant that the mechanical cleaning station could even be based upon different mechanisms, such as for example solutions which provide the use of air jets or spaces, in case compressed air, directed towards the surface of the release paper to be cleaned up.

Alternatively or additionally to those already described, even other solutions could be provided, for example a mechanism subjecting the release paper to vibration.

Moreover, it is to be meant that even several mechanical cleaning stations can be provided, in which different techniques are used.

For example, figure 5 shows schematically a possible embodiment of the present invention, wherein there is an additional mechanical cleaning station 40, immediately downstream of the station for applying the solvent solution 21. In particular the station 40 is so that the release paper is made to transit at least for a tract in vertical direction (where it is assumed that the apparatus is placed on a horizontal plane and that the feeding direction A of the paper is substantially horizontal).

During such tract covered vertically, the release paper is subjected to vibration, so that, by exploiting even the effect of the force of gravity a portion of the residues is separated even before that the paper itself has reached the subsequent cleaning station 31.

Moreover, according to some embodiments of the present invention, it is possible to provide one or more drying stations. A drying station upstream of the mechanical cleaning station would result in an advantage for the subsequent mechanical action for removing the residues. A drying station subsequent to the mechanical cleaning station would allow to be able to rewind the well dried belt of reconditioned release paper, adequately climatized in a new reel, ready for the subsequent reuses.

According to other embodiments of the present invention, one or more suction stations can advantageously further be provided.

A suction station for example can be provided for sucking the vapours released by the solvent solution, with the purpose of not polluting the surrounding air, above all for the operators’ welfare. To this purpose then it can be provided that the suction station also provides for a filtering of the sucked elements.

A suction station can be provided, additionally or alternatively to the one already described, for the suction of a light fraction of the residues separated from the release paper during the mechanical cleaning action. In this case, the filtering would allow the collection and disposal of the light fraction of the residues.

The present invention has been sofar described with reference to preferred embodiments thereof. It is to be meant that each one of the technical solutions implemented in the preferred embodiments, herein described by way of example, can advantageously be combined, differently to what described, with the other ones, to create additional embodiments, belonging to the same inventive core and however all within the protective scope of the here-below reported claims.

Claims

1. A reconditioning process of release paper in form of continuous belt (5), for the removal of residues from a surface (5’) of said release paper (5), comprising at least one step in which only said surface (5’) of the release paper (5) is placed in contact with a solvent solution.

2. The process according to claim 1, wherein said solvent solution is a polar solution.

3. The process according to claim 1 or 2, wherein said solvent solution comprises an alcohol, a ketone, water or a combination thereof.

4. The process according to claim 3, wherein said solvent solution comprises an alcohol selected from the group consisting of ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, tert-butyl alcohol, preferably ethyl alcohol.

5. The process according to claim 2, wherein said solvent solution is a hydroalcoholic solution or an aqueous solution comprising ethyl alcohol, preferably in a concentration from 30% to 95%, still more preferably in a concentration from 50% to 90%.

6. The process according to claim 2, wherein said solvent solution consists exclusively of absolute ethyl alcohol.

7. The process according to any one of the preceding claims, wherein said surface (5’) of the release paper (5) is placed in contact with a solvent solution by means of a roller (22), in turn in contact with a solvent solution, which by means of its rotation transfers said solvent on said surface (5’).

8. The process according to claim 7 wherein the roller (22) is a rubber and engraved roller.

9. The process according to any one of the preceding claims, further comprising at least a step for exerting a mechanical cleaning action for the removal of said residues.

10. The process according to any one of the preceding claims, wherein said mechanical action is exerted by means of a rotating brush (32).

11. The process according to any one of the preceding claims, further comprising at least a step for sucking and filtering vapours and/or and a light fraction of the residues removed from the surface of the release paper (5).

12. The process according to any one of the preceding claims, further comprising at least a step of drying the release paper subsequent to said step of applying a solvent solution.

13. The process according to claim 12, wherein said at least one drying step precedes or follows said step of exerting a mechanical cleaning action.

14. An apparatus (20) for the reconditioning of release paper in form of continuous belt (5), for the removal of residues from only one surface (5’) of said release paper (5), comprising at least a station (21) for applying a solvent solution (26) on said surface (5’) of the release paper (5).

15. The apparatus (20) according to claim 14, further comprising:

- at least a mechanical cleaning station (31) of said residues from said surface (5’) of the release paper (5); and

- means for feeding said release paper (5) along a feeding direction (A).

16. The apparatus (20) according to claim 14 or 15, wherein said application station (21) comprises a preferably engraved application roller (22) and a contrast roller (23) arranged so as to drag the release paper (5) along said feeding direction (A).

17. The apparatus (20) according to claim 16, wherein said application roller (22) is contained in a tank (25) suitable for containing said solvent solution (26).

18. The apparatus (20) according to one of claims 14 to 17, wherein said application station (21) further comprises a doctor blade (24) for adjusting the amount of solvent solution applied to the surface (5’) of the release paper (5).

19. The apparatus (20) according to one of claims 14 to 18, wherein said mechanical cleaning station (31) comprises a rotating brush (32) rotatably mounted on a rotation axis (R), arranged to be able to rotate in contact with said surface (5’) of the release paper (5).

20. The apparatus (20) according to claim 19, wherein said mechanical cleaning station (31) comprises means for translating said rotation axis (R) along an action direction (M) substantially orthogonal to the feeding direction (A), so as to bring said rotating brush (32) closer to/away from said surface (5’) of the release paper (5), to increase/decrease the pressure of said rotating brush (32) on said surface (5’) of the release paper (5).

21. The apparatus (20) according to claim 20, wherein said means for translating said rotation axis (R) comprises pneumatic actuators.

22. The apparatus (20) according to one of claims 14 to 21, further comprising at least one suction station, for the suction of vapours released by the solvent solution (26) and/or and a light fraction of the residues separated from the release paper during the mechanical cleaning action.

23. The apparatus (20) according to one of claims 14 to 22, further comprising at least one release paper drying station downstream of said station for applying a solvent solution.

24. The apparatus (20) according to claim 23, wherein said at least one drying station precedes or follows said mechanical cleaning station (31).