ITMI20130912A1 - IMPREGNATION SYSTEM OF ROLLS IN ABSORBENT MATERIALS WITH SOLVENT FOR INKS OR PRINTING PAINTS, FOR THE CLEANING OF ROLLERS OR PRINTING MACHINES - Google Patents

Description

Description of the patent application for industrial invention entitled:

"System for impregnating rolls in absorbent material with solvent for printing inks or varnishes, for cleaning rollers or sheets of printing machines"

The present invention relates to a cleaning system for printing machines based on the impregnation, by means of solvents or mixtures of solvents, of rolls of absorbent material. The latter are used for cleaning or removing inks or varnishes from sheets or rollers of printing machines.

There are various systems for cleaning printing sheets and cylinders intended to distribute the inks or paints necessary for the printing itself.

The most basic cleaning system consists in impregnating a piece of fabric, or similar fabric such as non-woven fabric, or a piece of absorbent paper with an appropriate solvent product of the printing inks and then manually cleaning the printing machine. .

A more sophisticated system involves the use of a material such as a non-woven fabric packaged in rolls of the same width as the printing machine. These rolls of non-woven fabric are placed in an automatic device which has the purpose of unwinding the roll in question, spraying the non-woven fabric or other absorbent material with a solvent product of the printing inks and putting the non-woven fabric soaked in solvent. in contact with the ink-stained cylinders of the machine, causing them to rotate. Thanks to this contact between the non-woven fabric soaked in solvent and the inked cylinders of the machine, the cylinders are cleaned by transferring the ink from the cylinders to the non-woven fabric impregnated with solvent; the ink-stained non-woven fabric is then rewound onto a shaft of the automatic system, while the clean non-woven fabric still available on the roll, when cleaning is to be carried out, is unrolled, sprayed with solvent and put back on contact with the ink-stained cylinder of the printing press.

A third automatic cleaning system involves the use of rolls of non-woven fabric pre-impregnated with solvent and packaged in sealed plastic packaging to allow transport and storage. These rolls originally pre-impregnated by the manufacturer are placed in an automatic device consisting of an equipment provided only with the device for unwinding the clean non-woven fabric and rewinding the dirty non-woven fabric. The device used with this system is much simpler as the use of pre-impregnated non-woven fabric does not require a solvent tank, distribution pumps, spray nozzles and exhaust or excess solvent recovery systems.

The limits of the above mentioned method are represented by the problems that arise due to the long stay in the warehouses of the rolls pre-impregnated with solvent. In fact, the non-woven material, maintained for a long time in contact with the solvent, macerates and loses part of its tensile strength; this loss of resistance is all the more accentuated the longer the non-woven material remains soaked in the solvent product. The solvent product, in turn, loses some of its chemical characteristics by reacting with the non-woven material and with the binders used for its manufacture. In addition, the air inevitably contained in the non-woven material tends to oxidize the solvent, resulting in a reduction in its cleaning capacity.

An alternative to the systems described above is the subject of international patent application WO 2004/106067 A filed by Arrio Vavassori Bisutti, which provides for the use of rolls of non-woven fabric placed in a special rigid container equipped with a suitably perforated lid, to which a plastic bag or bladder containing the solvent is superimposed. This bag is perforated by means of perforation, with the consequent leakage of the solvent contained therein, which falls into the suitably perforated container and from this onto the underlying rolls. Impregnation takes place only when the rolls are intended to be used.

However, this system is inconvenient to use, particularly in the case in which the rolls are of great length. Furthermore, there is a risk that, for example during transport or storage, accidental holes are created which could cause the solvent to escape.

A further alternative to the systems described above is the subject of the European patent EP 2 064 061 filed by Arrio Vavassori Bisutti. This patent describes a system for impregnating sheets or rolls of absorbent material with solvent or a mixture of solvents for printing inks or paints, for cleaning rollers and sheets of printing machines, in which a bag of flexible material impermeable to solvents for printing inks or varnishes, preferably plastic material, is divided into at least two compartments or sections adjacent to each other on one or more sides / dimensions of the bag, in which one of said compartments or sections contains the solvent element or solvent mixture , while the other compartment or section contains the other element, one or more rolls of absorbent material. The compartments or sections are divided between them by means of a removable seal divider / s, such as to free one or more openings that connect the compartments or sections, allowing the gradual flow of the solvent into the compartment or section containing the absorbent material . This type of system also allows the roll to be impregnated when it is used to clean sheets or rollers of printing machines.

In the case of large longitudinal rolls, intended for cleaning large format printing machines, a central compartment for the roll and two side compartments for the solvent or solvent mixture must be provided in the bag, in order to ensure impregnation uniform roll. Also this system is therefore rather bulky and awkward to use, as well as awkward to store and transport. Furthermore, this system does not ensure a total tightness of the solvent, in particular in the case in which this is present in high quantities. It may therefore happen that the solvent transmigrates, even in the presence of the dividing devices, into the compartment or section that contains the roll, impregnating it.

The object of the present invention is therefore to make available a system for impregnating rolls of absorbent material such as to overcome the drawbacks mentioned with reference to the known art.

This and other objects are achieved by an impregnation system according to claim 1.

To better understand the invention and appreciate its advantages, some of its non-limiting exemplary embodiments will be described below, referring to the attached figures in which:

Figure 1 is a side view of an impregnation system according to a possible embodiment of the invention;

Figure 2 is a schematic illustration of the impregnation system according to a possible embodiment of the invention.

With reference to the figures, a system for impregnating rolls of absorbent material with a solvent or a mixture of solvents for printing inks or varnishes, for cleaning rollers or sheets of printing machines, is indicated with reference 1.

The impregnation system 1 comprises a main bag 2 which delimits inside it a main housing 3. The main bag 2 is preferably closed, ie its interior is not accessible, except by breaking it, for example by cutting. The main bag 2 is made of a flexible material, impermeable to solvent and air. Alternatively, it can be open, for example at one end, and include suitable closing means (not shown in the figures).

The flexible material with which the main bag 2 is made is preferably a material or a plastic film, preferably having a thickness of between 85 and 200 micrometers.

In accordance with a possible embodiment, the main bag 2 is made starting from a film which comprises:

- a first layer made of a polyamide (PA), preferably with a thickness comprised between 15 and 35 micrometers, for example equal to 25 micrometers;

- a second layer made of polyethylene (PE), preferably with a thickness of between 70 and 165 micrometers, for example equal to 80 or 120 micrometers.

Alternatively, the main bag 2 can be made of different materials impermeable to the solvent or to the mixture of solvents, such as plasticized or paraffinized cartons, plasticized or paraffinized fabrics, possibly metallized polyesters.

The main bag 2 is preferably elongated in shape and, even more preferably, is closed at both ends by welding 11. Alternatively, as mentioned, for example one of the two ends, it can be opened and closed by means of suitable closure means.

The system 1 further comprises a roll 5 of absorbent material, suitable for being impregnated with the aforementioned solvent. The roll 5 is received inside the main housing 3 of the main bag 2.

The roll 5 can be obtained for example by wrapping the absorbent material on a tubular core, preferably made of cardboard, or plastic, or metal material. The absorbent material may, for example, comprise a woven fabric, a non-woven fabric, paper, or cloth.

The impregnation system 1 also comprises at least one auxiliary bag 6 made of a flexible material impermeable to the aforementioned solvents, as well as to the air. This auxiliary bag 6 is closed and contains the solvent inside it. The solvent is preferably selected from the group comprising organic solvents, such as aliphatic or aromatic compounds or their mixtures, or suspensions or emulsions or dispersions in water of such organic solvents.

Alternatively, the solvent can be selected from the group comprising solvents based on essential oils or based on mineral oils or hydrocarbon solvents.

The total amount of solvent contained in the auxiliary bags 6 is proportionally dosed to the absorption capacity of the absorbent material of the roll 5, and is such as to ensure adequate cleaning of the sheets or rollers of the printing machine, avoiding wastage of solvent. Preferably, the total amount of solvent contained as a whole in the auxiliary bag or bags is comprised between 50 and 150 cm <3> per square meter of surface of the absorbent material of the roll 5.

Preferably, inside the auxiliary bag or bags, in addition to the solvent or the mixture of solvents, an amount of air is kept, even more preferably in an amount less than or equal to 20% by volume.

The auxiliary bag 6 is arranged inside the main housing 3 delimited by the main bag 2. Therefore, the auxiliary bag 6 is arranged together with the roll 5 inside the main bag 2. Preferably, the auxiliary bag 6 is arranged adjacent and / or superimposed on the roll 5.

Note that the number and positioning of the auxiliary bag 6 (or of the auxiliary bags, if provided in a number greater than one) in the main housing 3 of the main bag 2 can be various.

In accordance with the embodiment illustrated in Figure 1, the roll 5 is arranged in the main bag 2 with the axis of the roll (coinciding with the axis of the tubular core on which the absorbent material is wound) longitudinal approximately parallel to the largest size of the main pouch. In the illustrated embodiment, two auxiliary bags 6 are provided, each having a larger size than the auxiliary bag. The two auxiliary bags 6 are arranged next to the roll 5, with the respective larger dimensions of the auxiliary bag approximately parallel to the largest dimension of the main bag, as well as to the axis of the roll. The two auxiliary bags 6 are arranged in succession and approximately aligned, with the largest dimensions approximately parallel to the axis of the roll. Naturally, the auxiliary bags 6 can be of a variable number. For example, there may be a single auxiliary bag, or a plurality of auxiliary bags. It should be noted that, in the case in which more auxiliary pockets 6 are provided, these can be of the same size but also of different sizes. Similarly, the quantity of solvent contained in the auxiliary bags 6 may be the same or different between them.

The auxiliary bags 6 are preferably made of a plastic material or a plastic film.

In accordance with a possible embodiment, the auxiliary bags 6 are made starting from a film, preferably having an overall thickness between 60 and 115 micrometers, for example equal to 85 micrometers. The film by which the auxiliary bag is made preferably comprises:

- a first layer of polyethylene perephthalate (PET), having a thickness preferably comprised between 5 and 20 micrometers, for example equal to 12 micrometers;

- a second layer of polyethylene (PE), having a thickness preferably comprised between 25 and 40 micrometers, for example equal to 33 micrometers;

- a third layer of ethyl vinyl alcohol (EVOH), having a thickness preferably comprised between 2 and 10 micrometers, for example equal to 5 micrometers;

- a fourth layer of polyethylene (PE), having a thickness preferably comprised between 20 and 40 micrometers, for example equal to 33 micrometers.

The main function of the first layer of polyethylene perephthalate (PET) is to ensure mechanical resistance to the auxiliary bag 6.

The second and fourth polyethylene (PE) layers ensure good weldability and good peelability, where the term “peelability” here means the ability to reduce the seal of the welds under certain conditions. We will return to this aspect later.

The third layer of ethyl vinyl alcohol (EVOH) has the main function of ensuring impermeability to solvents and air.

Alternatively, the auxiliary bag (or the auxiliary bags) 6 can be made of different materials impermeable to the solvent or to the mixture of solvents, such as plasticized or paraffinized cardboard, plasticized or paraffinized fabrics, possibly metallized polyesters.

The main bag 2 and the auxiliary bag 6 (or the auxiliary bags) are shaped in such a way that, following the application of a breaking force between a predefined minimum and maximum value on the main bag 2, such as to be transmitted through the main bag 2 to the auxiliary bag 6, the auxiliary bag 6 breaks and the main bag 2 remains intact, so as to cause the release of the solvent contained in the auxiliary bag 6 into the main housing 2 and the consequent impregnation of the roll 5 by the solvent itself.

With reference to the embodiment in figure 1, for example, the application of the forces F1 and F2, as indicated, from the outside on the main pocket 2, causes these forces to be transmitted to the two auxiliary pockets 6 contained in the main pocket 2 . The solvent contained in the auxiliary bags 6 therefore escapes inside the main bag 2, in the main housing 3, and impregnates the roll 5. Since the forces F1 and F2 do not cause the main bag 2 to break, the main housing 3 it is kept closed and sealed and therefore there are no solvent leaks outside the main bag 2. The solvent is then absorbed by the roll. Once the impregnation of the roll is completed, it is possible to open, or break, or cut the main bag 2, for example at one of its ends, so as to extract the roll 5 impregnated with solvent.

Preferably, the minimum value of the breaking force is between 3 Newton and 20 Newton. Even more preferably, it is equal to 5 Newton.

The predefined maximum value of the breaking force will generally depend on the characteristics of the material and of the conformation of the main bag. For example, if the force applied to the main bladder is very high, i.e. it is such as to generate forces in it greater than the breaking load of the material it is made of, the main bladder also breaks. However, the main bag and its material are such that the predefined maximum value of the breaking force is such as to avoid unwanted breakage of the main bag under the normal conditions of use of the system 1.

Note that the breaking force can be of the impulsive or non-impulsive type. For example, it is possible to apply the necessary force with a blow of a hand by a user (impulsive force) in correspondence with the areas of the main bag 2 where the auxiliary bags 6 are located. the system resting on a plane, or alternatively keeping the system raised, for example at one end of the main bag.

Alternatively, it is for example possible to apply suitable weights (non-impulsive force) in the same areas.

In order to achieve the aforementioned breaking behavior, the auxiliary pockets 6 preferably comprise one or more weakening zones. These weakening areas ensure that, following the application of the breaking force, the auxiliary pocket 6 breaks in correspondence with these weakening areas, remaining intact elsewhere.

In accordance with a possible embodiment, the auxiliary bag 6 (or the auxiliary bags) comprises sealing seams, for example for sealing the previously described film, so as to define an auxiliary housing 15 for receiving the solvent. Advantageously, the welds comprise at least one weakening weld, which creates one of the aforementioned weakening zones. In other words, the weakening weld is made in such a way as to remain intact when a force lower than the predefined minimum value of the breaking force is transmitted to the auxiliary bag, and to break when a breaking force greater than this minimum value is transmitted. default. As will be clear to the skilled person, the application of a breaking force on the auxiliary bag, preferably of compression, even concentrated, involves a deformation of the auxiliary bag and therefore an increase in pressure on the solvent, which therefore presses on the auxiliary bag. from inside. This pressing action results in the breakage of the weakening weld (s), but not the breakage of other parts of the auxiliary bag.

According to a possible embodiment, in addition to the aforementioned weakening welds, the auxiliary bag comprises one or more sealing welds, shaped in such a way as to remain intact following the application of the breaking force unlike the weakening welds which, as mentioned, they break allowing the solvent to escape.

In order to achieve this different breaking behavior between the weakening welds and the sealing welds, advantageously the thickness of the sealing welds is greater than the thickness of the weakening welds.

Preferably, the weakening seams are arranged along a smaller dimension of the auxiliary pocket, preferably at one or both of its ends. Alternatively, the weakening seams can be placed in different areas of the auxiliary pockets.

With reference to Figure 2, it schematically depicts the impregnation system 1 according to a possible embodiment of the invention. It shows the main bag 2 with the roll 5 and two auxiliary bags 6 arranged next to the roll in the main housing 3. The main bag has a larger size 7 and a smaller size 8. Clearly, the main bag 2 also has a third dimension not visible in the figure. The roll 5 is oriented with the roll axis R parallel to the larger dimension 7 of the main bag 2. The two auxiliary bags 6 also have a larger dimension 9 and a smaller dimension 10, in addition to a third dimension not visible in the figure . The auxiliary bags 6 have the largest dimension 9 parallel to the roll axis R as well as to the largest dimension 7 of the main bag 2. Furthermore, the two auxiliary bags are in succession and aligned next to the roll 5. The main bag 2 has two welds 11 placed along the smaller dimension 8 at the respective ends. The auxiliary bags 6 have a seal 12 arranged along the larger longitudinal dimension 9 and two welds 13 and 14 arranged along the smaller dimension 10, transversal, at the ends of the auxiliary bag. The longitudinal weld 12 is a sealing weld, that is, one that does not break as a result of the application of the breaking force. At least one of the welds 13 and 14 is instead a weakening weld. For example, the end transverse welds 14 are weakening welds, while the internal transverse welds 13 are sealing welds. The weakening welds 14 have a thickness w less than the thickness s of the sealing welds. Such welds of the auxiliary bags can for example be obtained by means of a welding machine having a longitudinal sealing bar and a pair of asymmetrical transverse sealing bars, such as to make welds with different thicknesses.

Advantageously, the material with which the auxiliary bags 6 are made, for example the previously described film, is subjected to an anti-static treatment before carrying out the welds. It has in fact been observed that the static electricity generated by the sliding of the film causes the adhesion of a few drops of solvent on the internal surface of the auxiliary pockets, which could lead to sealing defects in the welds. The anti-static treatment can be carried out for example by means of pairs of anti-static bars such as to cancel the electrostatic charges accumulated by the film for the realization of the auxiliary bags.

EXAMPLE

An example of a possible impregnation system according to the invention is now reported.

Characteristics of the main bag Made in a film with:

- a first layer made of polyamide (PA) with a thickness of 25 micrometers;

- a second layer made of polyethylene (PE) with a thickness of 120 micrometers.

Transverse welds at the ends with a thickness of 8 mm.

Characteristics of the auxiliary bags Made in a film with:

- a first layer of polyethylene perephthalate (PET), having a thickness of 12 micrometers;

- a second layer of polyethylene (PE), having a thickness of 33 micrometers;

- a third layer of ethyl vinyl alcohol (EVOH), having a thickness of 5 micrometers;

- a fourth layer of polyethylene (PE), having a thickness of 33 micrometers;

- a longitudinal sealing weld along the longer side and a transversal sealing weld along the smaller dimension at a first end, with a thickness of 15 mm;

- a transversal weakening weld along the smaller dimension at a second end, with a thickness of 8 mm;

welding time of sealing and weakening welds: 0.8 seconds;

welding temperature of sealing and weakening welds: 140 ° C;

largest dimension = 360 mm;

smaller size = 35 mm.

The minimum default value of the breaking force capable of breaking the auxiliary bags while keeping the main bag intact is, based on this configuration, equal to 5 Newton.

It should be noted that the impregnation system according to the invention can be made available as a kit in which the main bag, hermetically closed (for example by welding) or closed by closure means, contains the roll and the auxiliary bags inside. .

Alternatively, the main bag can be made open or can be opened, with the auxiliary bags and / or the roll separated from it, ie not arranged inside it. The auxiliary bags and / or the roll can in this case be inserted inside the main bag at the time of impregnation.

From the description provided above, the skilled person will be able to appreciate how the impregnation system according to the invention allows effective impregnation of the roll in the face of overall dimensions of the system which are approximately equal to, or slightly greater than, those of the roll itself. . At the same time, the impregnation system allows the use of the right amount of solvent necessary for cleaning the printing sheets or rollers, avoiding solvent waste.

The skilled person will also be able to appreciate that in the impregnation system according to the invention it is not necessary to use additional elements, such as for example drilling means, necessary in the system according to WO 2004/106067 A, or dividing devices, necessary in the system according to EP 2 064 061. Impregnation is therefore simple and there is a low risk of breakage of the system or accidental impregnation of the roll, for example during transport or storage of the system, due to unwanted decanting of the solvent into the compartment where the roll.

The skilled person, in order to meet specific contingent needs, may make numerous additions, modifications, or replacements of elements with other functionally equivalent to the described embodiments of the impregnation system, without however departing from the scope of the attached claims.

Claims (20)

CLAIMS 1. System (1) for impregnating rolls of absorbent material with a solvent or a mixture of solvents for printing inks or varnishes, for cleaning rollers or sheets of printing machines, comprising: - a main pocket (2) of flexible material impermeable to said solvent or mixture of solvents, which delimits inside it a main housing (3); - a roll (5) of absorbent material received inside said main housing (3); - at least one auxiliary bag (6) of flexible material impermeable to said solvent or mixture of solvents, containing inside said solvent or mixture of solvents, arranged inside the main housing (3); in which said main pocket (2) and said at least one auxiliary pocket (6) are shaped in such a way that, following the application of a breaking force (F1, F2) between a minimum and a maximum value predefined on the main bag (2), such as to be transmitted on the at least one auxiliary bag (6), the at least one auxiliary bag (6) breaks and the main bag (2) remains intact, so as to cause the escape of the solvent or of the solvent mixture in the main housing (2) and the consequent impregnation of the roll (5). Impregnation system (1) according to claim 1, wherein said predefined minimum value of the breaking force is comprised between 3 Newton and 20 Newton. Impregnation system (1) according to claim 1 or 2, wherein said roll (5) develops along a longitudinal roll axis (R), said main bag (2) comprises a larger dimension (7) of main bag , and said at least one auxiliary bag (6) comprises a larger dimension (9) of the auxiliary bag, said roll (5) being arranged with the axis of roll (R) approximately parallel to the larger dimension (7) of the main bag , and said at least one auxiliary pouch (6) being arranged next to the roll (5) with the largest dimension (9) of auxiliary pouch approximately parallel to the axis of the roll (3). Impregnation system (1) according to the preceding claim, comprising two or more auxiliary bags (6) placed in succession approximately aligned with the larger dimensions of auxiliary bag (9) approximately parallel to the roll development axis (R). Impregnation system (1) according to any one of the preceding claims, wherein said at least one auxiliary bag (6) comprises one or more weakening zones such as to allow the breaking of the at least one auxiliary bag (6) following the application of said breaking force (F1, F2). 6. Impregnation system (1) according to the preceding claim, wherein said at least one auxiliary bag (6) is made starting from a folded film closed by welding, said welds comprising at least one weakening weld (14) which creates a of said weakening zones. 7. Impregnation system (1) according to the preceding claim, wherein said welds comprise said at least one weakening weld (14) and one or more sealing welds (12, 13), shaped in such a way that, following the application of said breaking force (F1, F2), said one or more sealing welds (12, 13) remain intact and said at least one weakening weld (14) breaks, allowing the breaking of at least one auxiliary pocket (6 ). Impregnation system (1) according to the preceding claim, wherein the thickness (w) of said at least one weakening weld (14) is less than the thickness (s) of said one or more sealing welds (12, 13) . Impregnation system (1) according to claim 7 or 8, wherein said one or more sealing welds comprise a first sealing weld (12) arranged according to the larger dimension of auxiliary bag (9) and a second sealing weld (13) arranged according to a minor dimension (10) of auxiliary pocket orthogonal to the main dimension of auxiliary pocket (9) at a first end of said auxiliary pocket (6), and said at least one weakening weld comprises a weakening weld (14) arranged according to said minor dimension of auxiliary well (10) at a second end of said auxiliary well (6) opposite to the first end. Impregnation system (1) according to any one of claims 1 to 9, wherein said at least one auxiliary bag (6) is made starting from a film comprising: - a first layer of polyethylene perephthalate (PET); - a second layer in polyethylene (PE); - a third layer of ethyl vinyl alcohol (EVOH) - a fourth layer in polyethylene (PE). Impregnation system (1) according to the preceding claim, wherein: - said first layer of polyethylene perephthalate (PET) has a thickness of between 5 and 20 micrometers, and / or - said second layer of polyethylene (PE), has a thickness of between 25 and 40 micrometers, and / or - said third layer of ethyl vinyl alcohol (EVOH) has a thickness of between 2 and 10 micrometers, and / or - said fourth polyethylene (PE) layer has a thickness between 20 and 40 micrometers. 12. Impregnation system (1) according to claim 10 or 11, in which said film from which at least one auxiliary bag (6) is made is subjected to anti-static treatment. Impregnation system (1) according to any one of claims 1 to 9, wherein said at least one auxiliary bag (6) is made of a material selected from the group consisting of: plasticized or waxed cardboard, plasticized or waxed fabrics, polyesters , metallized polyesters. Impregnation system (1) according to any one of claims 1 to 13, wherein said main bag (2) is made starting from a film comprising: - a first layer made of a polyamide (PA); - a second layer made of polyethylene (PE). Impregnation system (1) according to the preceding claim, wherein: - said first layer made of a polyamide (PA) has a thickness comprised between 15 and 35 micrometers, and / or; - said second layer made of polyethylene (PE) has a thickness of between 70 and 165 micrometers. Impregnation system (1) according to any one of claims 1 to 13, wherein said main bag (6) is made of a material selected from the group consisting of: plasticized or waxed cardboard, plasticized or waxed fabrics, polyesters, polyesters metallics. Impregnation system (1) according to any one of the preceding claims, wherein said solvent or solvent mixture contained in the at least one auxiliary bag (6) is in a total quantity comprised between 50 and 150 cm <3> per square meter of absorbent material surface of said roll (5). Impregnation system (1) according to any one of the preceding claims, wherein said at least one auxiliary bag (6) contains an amount of air lower than or equal to 20% by volume. 19. Impregnation system (1) according to any of the preceding claims, in which said at least one auxiliary bag (6) is separated from the main bag (2) and is inserted into it only at the time of impregnation of the roll (5). 20. Impregnation system (1) according to any of the preceding claims, in which said roll (5) is separated from the main bag (2) and is inserted into it only at the time of impregnation.