Cleaning cloth roll, and related device and method

Abstract

To provide a roll of a cleaning cloth impregnated with a cleaning composition for cleaning a printing cylinder in a printing system.SOLUTION: A roll of a cleaning cloth is used for cleaning a printing cylinder in a printing system. The cleaning cloth (13) is impregnated with a cleaning composition containing an organic solvent and a cellulose solubilizer. This roll is wound around a core material (14), and may be inserted in a removable sealed bag (15) which is so configured as to seal around the roll (12) of the cleaning cloth (13) in order to prevent evaporation of the cleaning composition before use.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a roll of cleaning fabric impregnated with a cleaning composition for cleaning print cylinders in a printing system. The present invention also relates to the cleaning composition, the cleaning fabric, and a method of cleaning print cylinders and a method of forming the roll. [Background technology]

[0002] In order for a printing cylinder to achieve the desired printing results, such cylinders in a printing system need to be cleaned periodically. An example of a cleaning device for a printing system is shown in U.S. Patent No. 7,219,605 B2. Several different cleaning methods are known, such as spraying a cleaning liquid onto the cylinder or manually cleaning the cylinder by means of a cleaning cloth soaked in a cleaning liquid.

[0003] The cleaning cloth is often pre-impregnated with a cleaning composition that is configured to dissolve and remove residual ink from the printing cylinder. Paper residues tend to adhere to the surface of the printing cylinder. The adhered paper dust is difficult to dissolve by the cleaning composition, and therefore the paper residues need to be removed from the cylinder before the cleaning process with the cleaning cloth can begin. Therefore, it is a common practice to spray water onto the printing cylinder by a spray bar or spray nozzle installed in the printing system. For example, US Patent Application Publication No. 2005250659A1 describes how water can be sprayed onto the cylinder of a printing system to remove dust and paper residues.

[0004] However, the spray bars, nozzles, and water tubes that direct water to the nozzles are prone to clogging due to the hostile environment within the printing system, which includes paper waste, residual ink, and other contaminants that can clog the spray devices. Limescale in the water used can also cause clogging.

[0005] Examples of prior art arrangements that attempt to solve the problem of clogging pipes and nozzles in printing systems are shown in EP 435269 A1 and EP 878304 A1. Further background art is reflected in the literature, for example, in US 5340495 A and GB 1365464 A. From the above, it can be seen that there is room for improvement with regard to problems such as clogged nozzles and pipes in printing systems. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 7,219,605 B2 [Patent Document 2] US Patent Application Publication No. 2005250659A1 [Patent Document 3] European Patent Application Publication No. 435269A1 [Patent Document 4] European Patent Application Publication No. 878304A1 [Patent Document 5] U.S. Patent No. 5,340,495A [Patent Document 6] GB Patent Application Publication No. 1365464A Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a concept which improves over the prior art and which solves or at least mitigates the problems discussed above. This object is achieved by the techniques set out in the attached independent claims, with preferred embodiments defined in the associated dependent claims. [Means for solving the problem]

[0008] The present invention is based - inter alia - on the technical idea that if the cleaning liquid, also referred to herein as cleaning composition, itself is able to dissolve cellulosic paper residues, the step of spraying water on the printing cylinder can be omitted. The inventors have surprisingly found that by adding a cellulosic solubilizer, preferably a non-aqueous cellulosic solubilizer, also referred to herein as water substitute, to the cleaning liquid, the paper residues are dissolved from the printing cylinder. Thus, the first washing step, i.e. spraying with water, can be eliminated from the cleaning process of the printing system. As many printing systems need to be cleaned multiple times each day, the cleaning composition of the present invention saves time. Moreover, the laborious process of cleaning and / or replacing clogged water tubes or spray bars or nozzles is no longer an issue.

[0009] In a first aspect, a roll of cleaning cloth is provided that is adapted and configured to clean a printing cylinder of a printing system. The cleaning cloth is impregnated with a cleaning composition that includes an organic solvent and a cellulose solubilizer. This is an advantageous cleaning composition because the cellulose solubilizer allows the cleaning process to eliminate the currently common water spray step in the printing system cleaning process. The organic solvent provides the cleaning composition with the property of dissolving and removing ink from the printing cylinder.

[0010] In one embodiment, the cleaning composition comprises less than 10% by weight of water, preferably less than 5% by weight of water. In another embodiment, the cleaning composition comprises less than 2% by weight of water. The presence of more than 2% by weight of water in the cleaning composition may cause the cleaning composition to evaporate. Furthermore, adding higher concentrations of water to the cleaning composition reduces the ink dissolving properties of the cleaning composition.

[0011] Preferably, the water content of the cleaning composition is less than 1% by weight, most preferably less than 0.5% by weight.

[0012] In one embodiment, the cellulose solubilizer comprises an ethanolamine moiety, in which the ethanolamine moiety is defined as shown in Formula I. The ethanolamine moiety provides a hydrophilic portion to the solubilizer and facilitates the solubilizer in dissolving water-soluble contaminants, such as paper residue, from the printing cylinder. [ka]

[0013] In one embodiment, the cellulose solubilizer in the cleaning composition containing the ethanolamine moiety is ethanolamide. Ethanolamide dissolves paper residue and other water-soluble impurities attached to the printing cylinder. Furthermore, the swelling of rubber in the printing system caused by contact with the cleaning composition can be kept within an acceptable range by using ethanolamide.

[0014] In another embodiment, the ethanolamide in the cleaning composition is coconut diethanolamide. The addition of coconut diethanolamide has been found to provide the cleaning composition with favorable ink solubility properties in addition to dissolving paper residue from the printing cylinder. Coconut diethanolamide effectively absorbs moisture from the environment. It is likely that coconut diethanolamide effectively dissolves the paper, which in turn has the effect of breaking down paper dust and dissolving paper residue from the printing cylinder. It has also been shown that coconut diethanolamide reduces the electrical resistance of the cleaning composition.

[0015] In yet another embodiment, the cellulose solubilizer in the cleaning composition containing an ethanolamine moiety is ethanolamine, which dissolves paper residue and other water-soluble impurities adhering to the printing cylinder, and furthermore, swelling of rubber in the printing system due to contact with the cleaning composition is within acceptable limits when using ethanolamine.

[0016] In a further embodiment, the ethanolamine in the cleaning composition is triethanolamine. The addition of triethanolamine has been found to provide the cleaning composition with favorable ink solubility properties in addition to dissolving paper residue from the printing cylinders.

[0017] In one embodiment, the cellulose solubilizer is a glycol ether, which is advantageous as a cellulosic solubilizer because these compounds have the favorable solvent properties of low molecular weight ethers and alcohols and are therefore capable of dissolving paper residues and other water-soluble contaminants from the printing cylinders.

[0018] In another embodiment, the cellulose solubilizer is a C2-C6 alkanediol. The hydroxyl groups of the C2-C6 alkanediol impart hydrophilic properties to the compound, making it capable of dissolving paper residues and other water-soluble contaminant particles.

[0019] In yet another embodiment, the C2-C6 alkanediol is ethylene glycol (ethane-1,2-diol), a C2 alkanediol that has particularly favorable properties for dissolving paper residue from printing cylinders.

[0020] In one embodiment, the cellulose solubilizer is a hydrophilic surfactant that dissolves water-soluble contaminant particles, such as paper residue, from the print cylinder.

[0021] In a further embodiment, the hydrophilic surfactant is a superwetting agent. Preferably, the superwetting agent is an amphoteric betaine, an anionic organic sulfate, or an amine oxide. The superwetting agent enables the cleaning composition to dissolve water-soluble contaminants from the printing cylinder, such as paper residue. Furthermore, only low concentrations of superwetting agent are required to dissolve paper residue, etc. Thus, the concentration of the superwetting agent may be as low as 0.05-0.1 wt. %. Using a low concentration of cellulosic solubilizer is preferred since the amount of organic solvent that provides ink solubility to the cleaning composition can be kept at a high level.

[0022] In another embodiment, the content of the cellulose solubilizer in the cleaning composition is 0.05-20% by weight, preferably 0.075-10% by weight, most preferably 0.1-5% by weight. The concentration of the cellulose solubilizer should be balanced with the concentration of the organic solvent(s). If the concentration of the cellulose solubilizer is higher than 20% by weight, the ink solubility of the cleaning composition will decrease. If the concentration of the solubilizer is too low, i.e., less than 0.05% by weight, the cleaning composition will not favorably dissolve and remove paper residues.

[0023] In one embodiment, the content of the organic solvent in the cleaning composition is 80 to 99.05% by weight, preferably 90 to 99.025% by weight, and most preferably 95 to 99.9% by weight. The concentration of the organic solvent varies with the concentration of the cellulosic material solubilizer. If the concentration of the organic solvent is higher than 99.9% by weight, the concentration of the cellulose solubilizer will be too low and the cleaning composition will not be able to dissolve the paper residue from the printing cylinder. If the concentration of the organic solvent is too low, i.e., less than 80% by weight, the cleaning composition will not adequately dissolve and remove the ink residue.

[0024] In yet another embodiment, the cleaning fabric is wound around a core to form a roll. This is preferred because the core may be efficiently attached to the shaft of a cleaning cassette. Furthermore, the cleaning fabric is easier to handle and more protected when wrapped around a core.

[0025] In one embodiment, to prevent the cleaning composition from evaporating before use, the roll is inserted into a removable sealing pouch configured to seal around the roll of cleaning cloth. Preferably, the removable sealing pouch is made of plastic. The plastic sealing pouch prevents the cleaning composition from evaporating. Thus, the plastic seal gives the roll a longer shelf life before use and protects the roll from the environment.

[0026] In a further embodiment, the roll of cleaning cloth is vacuum-packed in the sealed pouch. This vacuum packaging prevents the cleaning composition from migrated inwards by diffusion in the pouch. Uneven distribution of the cleaning composition due to accumulation of the cleaning composition in certain areas of the roll during storage will result in uneven cleaning results during use. However, vacuum packaging ensures uniform distribution of the cleaning liquid in the roll and therefore high quality cleaning results. Furthermore, the shelf life of the roll is extended due to vacuum sealing. Vacuum packaging also prevents other compounds and / or impurities from entering the sealed pouch and damaging the roll of cleaning cloth.

[0027] In a second aspect, a cleaning composition is provided that is adapted and configured to clean a printing cylinder of a printing system, the cleaning composition comprising an organic solvent and a cellulose solubilizer, the cleaning composition being capable of being transferred, e.g., sprayed, onto a cleaning cloth or onto a printing cylinder to be cleaned without the need for the addition of water to dissolve paper residue from the printing system.

[0028] In one embodiment, the cleaning composition comprises less than 10% water by weight, preferably less than 5% water by weight.

[0029] In another embodiment, the cleaning composition comprises less than 2% water by weight.

[0030] In one embodiment, the cellulose solubilizer in the cleaning composition comprises an ethanolamine moiety, in which the ethanolamine moiety is defined as shown in Formula I. The ethanolamine moiety provides a hydrophilic portion to the solubilizer and facilitates the solubilizer in dissolving water-soluble contaminants, such as paper residue, from the printing cylinder. [ka]

[0031] In one embodiment, the cellulose solubilizer in the cleaning composition containing the ethanolamine moiety is ethanolamide. Ethanolamide dissolves paper residue and other water-soluble impurities attached to the printing cylinder. Furthermore, the swelling of rubber in the printing system caused by contact with the cleaning composition can be kept within an acceptable range when using ethanolamide.

[0032] In another embodiment, the ethanolamide in the cleaning composition is coconut diethanolamide. The addition of coconut diethanolamide has been found to provide the cleaning composition with favorable ink solubility.

[0033] In yet another embodiment, the cellulose solubilizer in the cleaning composition containing an ethanolamine moiety is ethanolamine, which dissolves paper residue and other water-soluble impurities adhering to the printing cylinder, and furthermore, swelling of rubber in the printing system due to contact with the cleaning composition is within acceptable limits when using ethanolamine.

[0034] In a further embodiment, the ethanolamine in the cleaning composition is triethanolamine. The addition of triethanolamine has been found to provide the cleaning composition with favorable ink solubility properties in addition to dissolving paper residue from the printing cylinders.

[0035] In one embodiment, the cellulose solubilizer is a glycol ether, which is advantageous as a solubilizer because these compounds have the favorable solvent properties of low molecular weight ethers and alcohols, and therefore can dissolve paper residues and other water-soluble contaminants from the printing cylinder.

[0036] In another embodiment, the cellulose solubilizer in the cleaning composition is a C2-C6 alkanediol. The hydroxyl groups of the C2-C6 alkanediol impart hydrophilic properties to the compound, making it capable of dissolving paper residue and other water-soluble contaminant particles.

[0037] In yet another embodiment, the C2-C6 alkanediol in the cleaning composition is ethylene glycol (ethane-1,2-diol), a C2 alkanediol that has particularly favorable properties for dissolving paper residue from printing cylinders.

[0038] In one embodiment, the cellulose solubilizer in the cleaning composition is a hydrophilic surfactant that dissolves water-soluble contaminant particles, such as paper residue, from the print cylinder.

[0039] In a further embodiment, the hydrophilic surfactant in the cleaning composition is a superwetting agent. Preferably, the superwetting agent is an amphoteric betaine, an anionic organic sulfate, or an amine oxide. The superwetting agent enables the cleaning composition to dissolve water-soluble contaminants from the printing cylinder, such as paper residue. Furthermore, only low concentrations of superwetting agent are required to dissolve such paper residue. Thus, the concentration of the superwetting agent may be as low as 0.05-0.1 wt. %. Using low concentrations of non-aqueous cellulosic solubilizers is preferred because the amount of organic solvent that provides ink solubility to the cleaning composition can be kept at a high level.

[0040] In another embodiment, the content of the cellulose solubilizer in the cleaning composition is 0.05 to 20% by weight, preferably 0.075 to 10% by weight, and most preferably 0.1 to 5% by weight. The concentration of the cellulose solubilizer is determined by the concentration of the organic solvent(s). A balance must be struck between the strength of the solubilizer and the ink solubility of the cleaning composition. If the concentration of the cellulosic solubilizer is higher than 20% by weight, the ink solubility of the cleaning composition is reduced. If the concentration of the solubilizer is too low, i.e., less than 0.05% by weight, the cleaning composition will not adequately dissolve and remove paper residue.

[0041] In one embodiment, the content of organic solvent in the cleaning composition is 80-99.05% by weight, preferably 90-99.025% by weight, most preferably 95-99.9% by weight. The concentration of the organic solvent needs to be balanced against the concentration of the cellulosic solubilizer. If the concentration of the organic solvent is higher than 99.9% by weight, the concentration of the cellulosic solubilizer will be too low and the cleaning composition will not be able to dissolve the paper residue from the printing cylinder. If the concentration of the organic solvent is too low, i.e., less than 80% by weight, the cleaning composition will not favorably dissolve and remove the residual ink.

[0042] In a third aspect, a cleaning cloth adapted and configured for cleaning a print cylinder of a printing system is provided, the cleaning cloth being impregnated with a cleaning composition comprising an organic solvent and a cellulose solubilizer.

[0043] In one embodiment, the cleaning composition comprises less than 10% water by weight, preferably less than 5% water by weight.

[0044] In another embodiment, the cleaning composition comprises less than 2% water by weight. If the cleaning composition comprises more than 2% water by weight, the cleaning composition will evaporate.

[0045] The cleaning cloth may be manually rubbed or stroked against the print cylinder, or may be placed in another type of cleaning device not described herein.

[0046] In a fourth aspect, there is provided a method for cleaning a print cylinder of a printing system with a cleaning roll, the method comprising the steps of unrolling at least a portion of a cleaning cloth impregnated with a cleaning composition from a roll, and placing at least a portion of the cleaning cloth in contact with the print cylinder.

[0047] In a fifth aspect, there is provided a method of forming a roll, the method comprising the steps of impregnating a cleaning fabric with a cleaning composition, wrapping the cleaning fabric around a core to form a roll, and inserting the roll into a sealable bag, which is preferably vacuum packaged.

[0048] In one embodiment, the cleaning cloth is impregnated with the cleaning composition after being wrapped around a core.The advantage of this is that when the cleaning cloth is wrapped around a core, the cleaning cloth may be easier to handle and impregnate.For example, the cleaning cloth wrapped around a core can be placed in a sealable bag and impregnated while in the sealable bag.In this way, any loss of the cleaning composition is reduced.This also reduces the spread of the cleaning composition to the surroundings.

[0049] In a sixth aspect, there is provided a use of a roll of cleaning cloth for cleaning a print cylinder of a printing system. [Brief description of the drawings]

[0050] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, embodiments of the present invention will be described. Reference is made to the accompanying drawings, which show: A non-limiting example of how the concepts can be implemented is described.

[0051] [Figure 1] FIG. 1 shows a cross-section of a typical printing system comprising a cylinder and a cleaning cassette arrangement with a roll of cleaning cloth and a spray nozzle bar. [Diagram 2] FIG. 2 shows an enlarged portion of FIG. [Diagram 3] FIG. 3 shows a perspective view of a roll vacuum packaged in a sealed bag. [Figure 4] FIG. 4 shows the roll shown in FIG. 3 with the sealed pouch partially removed. [Diagram 5] FIG. 5 shows the test results from the ink solubility test. [Figure 6] FIG. 6 shows the test results from the paper residue and ink washout tests. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] With reference to Figure 1, a typical printing unit or printing system 1 is shown with several printing cylinders and rollers 2, 3, 4, 5, 6. The printing system 1 described herein has an impression cylinder 2 (the largest printing cylinder, bottom left of Figure 1), a blanket cylinder 3 (a medium size cylinder adjacent to the impression cylinder) with a blanket 3', also referred to herein as a rubber sheet 3', and a plate cylinder 4 (a medium size cylinder adjacent to the blanket cylinder). The blanket 3' is typically approximately 2 mm thick. The printing system 1 further has several form rollers (ink form rollers) 5 (small rollers that are not damping rollers) and several damping rollers 6 (five small size rollers toward the bottom right).

[0053] The set of form rollers 5 is in communication with an ink source 8 which provides ink to the form rollers 5. The set of damping rollers 6 is in communication with a damping source, in this case a water bath 9, which provides water to the damping rollers 6. The printing system 1 further comprises a cleaning machine or cleaning cassette 10 which houses a cleaning device or roll 12 provided with a cleaning cloth 13, also called a cleaning fabric.

[0054] 1 and 2, spray devices 17a and 17b used in the current cleaning system are shown. The spray devices 17a and 17b are shown with dashed lines to indicate that they belong to the current cleaning system. The cleaning cassette 10 includes the spray devices 17a and 17b, also referred to herein as a spray nozzle array, having spray nozzles located at either positions 17a or 17b. The spray devices 17a and 17b are arranged and configured to spray water onto the rubber sheet 3' of the blanket cylinder 3 to remove paper residue and other water-soluble debris adhering to the rubber sheet 3' on the printing cylinder 3. As shown in FIGS. 1 and 2, the spray devices 17a and 17b used in the current cleaning system may be located inside the cleaning cassette 10 facing the blanket cylinder 3, or may be located adjacent to the cleaning cassette 10 facing the blanket cylinder 3.

[0055] Figure 2 shows a cleaning cassette 10 of the printing system 1 shown in Figure 1. The cleaning cassette 10 includes a cleaning roll 12 that includes a bobbin or core 14. A cleaning fabric 13 is wrapped around the core 14, which may be solid or hollow and made from any suitable material, such as plastic, paper, metal, etc. Additionally, the core 14 can have a variety of cross sections, with the design described herein having a circular cross section. The cleaning cassette 10 of Figures 1 and 2 further includes a collection roller 16.

[0056] 3 shows a roll 12 in perspective view, vacuum packaged in a sealed bag 15, preferably made from a plastic material. The roll 12 includes a core 14 and a cleaning fabric 13 wrapped or wound around the core 14. The cleaning fabric 13 is saturated with a cleaning liquid, also referred to herein as a cleaning composition, or the like. The cleaning solution is impregnated.

[0057] FIG. 4 shows the roll 12 shown in FIG. 3 with the sealed bag 15 partially removed. Preferably, the bag 15 is tubular and constructed of a multi-layer plastic film. A plastic film suitable for this purpose is a three-layer film based on a first layer of polyethylene (PE) providing a fluid barrier, a second intermediate layer of polyamide (PA) providing strength, and a third layer of polyethylene (PE) providing a fluid barrier and sealing layer. This three-layer plastic film has given good results in practical tests. The thickness of the sealing film is designed to allow easy removal from the roll 12, as shown in FIG. 4. Preferably, the sealed bag 15 is vacuum-packed by heat sealing the bag 15.

[0058] Figure 5 shows the test results from the ink solubility test and Figure 6 shows the results from the paper residue cleaning test. The experiments and their results are described in more detail in the Experimental section below.

[0059] The printing operation and cleaning of the printing system 1 will now be described in more detail. With reference to FIG. 1, when the printing system 1 is performing a printing operation, water is transported towards the cylinders via the damping rollers 6, which collect water from a damping source 9. Thus, the water arrives and is present on the non-pressure surface that occurs between the cylinders 2, 3, 4. Then, ink is transported towards the cylinders 3, 4, 5 by the ink rollers 5, which collect ink from an ink source 8. Then, the print is transferred to the blanket cylinder 3 and to a material, for example paper. The material to receive the print, for example paper, is placed between the rubber sheet 3' on the blanket cylinder 3 and the impression cylinder 2. Here, the printing operation is performed and the print is transferred from the rubber sheet 3' to the material. The cylinder and roller settings shown and described in this specification are only one example of a setting of a printing system.

[0060] To maintain sufficient print quality, the printing system 1 needs to be cleaned more or less frequently depending on the type and application. In prior art printing systems, the cleaning process typically begins with spraying the printing cylinders with a liquid (most often water) that dissolves cellulose in the form of paper dust and other water-soluble impurities. Once the water-soluble contaminants such as paper residues have been removed, the cleaning cassette 10 can perform its cleaning. The cleaning composition impregnated in the cleaning cloth 13 removes, among other things, residual ink from the printing cylinders 2, 3, 4, 5.

[0061] Cleaning processes known in the art include two separate steps. The first water washing step, where water is sprayed onto the blanket cylinder, can be time consuming and inefficient. Furthermore, the sprayer and the water tubes that lead water to the sprayer are prone to clogging. Clogging of the sprayer and the tubes that supply water to the sprayer occurs due to contamination from paper residues, limescale in the water, ink residues and other debris. These contaminant particles can pass through the spray openings of the device and clog the internal cavities of the water tubes.

[0062] According to the present disclosure, when cleaning the printing system 1, a pre-cleaning step of spraying water onto the blanket cylinder 3 using spray devices 17a, 17b to remove paper residue and other water-soluble debris is not required because the paper residue is dissolved by the cleaning composition of the present disclosure.

[0063] The cleaning composition of the present disclosure comprises at least one organic solvent for diluting and / or dissolving the residual ink and at least one cellulose solubilizer configured to dissolve cellulosic materials such as wastepaper from cylinders 2, 3, 4, 5. Thus, the water spraying step is no longer necessary, i.e. spray devices 17a, 17b can be omitted. The cellulosic solubilizer is intended to dissolve the water-soluble cellulosic wastepaper. However, when water is added to the cleaning composition, the water evaporates, resulting in the cleaning composition being washed away. loses its ability to dissolve water-soluble impurities. Replacing the water spray step by adding water to the cleaning composition is therefore not an option. Instead, the cellulosic solubilizer should be low volatile organic compounds (low VOC). The possible compound groups presented below from which the cellulosic solubilizer can be selected are all low VOC.

[0064] The concentration of the cellulosic solubilizer in the cleaning composition is 0.05-20% by weight, preferably 0.06-15% by weight, more preferably 0.075-10% by weight, and most preferably 0.1-5% by weight. The concentration of the cellulosic solubilizer must be balanced with the concentration of the organic solvent(s). If the concentration of the cellulosic solubilizer is higher than 20% by weight, the ink solubility of the cleaning composition will decrease. If the concentration of the solubilizer is too low, i.e., less than 0.05% by weight, the cleaning composition will not favorably dissolve and remove paper residues.

[0065] The cellulosic solubilizer may be any compound selected from the group consisting of compounds containing an ethanolamine moiety, glycol ethers, C2-C6 alkanediols, hydrophilic surfactants, superwetting agents, or combinations of such compounds.

[0066] Preferred hydrophilic surfactants are so-called superwetting agents, such as amphoteric betaines, anionic organic sulfates, amine oxides, etc. These superwetting agents are strong wetting agents, meaning that even low concentrations are sufficient to effectively dissolve cellulosic materials. The concentration of superwetting agents in the cleaning composition may be as low as 0.1% by weight. Other hydrophilic surfactants can also be used in the cleaning composition as cellulosic material solubilizers.

[0067] The C2-C6 alkanediol may be, for example, propylene glycol, tetramethylenediol (butane-1,4-diol) or ethylene glycol. Preferably, the C2-C6 alkanediol is ethylene glycol.

[0068] Examples of glycol ethers that may be used as the cellulosic solubilizer are, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, phenoxyethanol, pentaethylene glycol monododecyl ether and alkylene polyglycol ethers.

[0069] The ethanolamine moiety is defined herein as a —(N(CH 2 CH 2 OH))— moiety and as shown in Formula I. [ka]

[0070] The compound containing an ethanolamine moiety is, for example, an alkanolamine or alkanolamide, preferably an ethanolamine or ethanolamide, most preferably a triethylamine or triethylamine. It may be ethanolamine or coconut diethanolamide.

[0071] It is understood that combinations of the different cellulose solubilizers presented herein can be used in the cleaning compositions according to the present disclosure.

[0072] The organic solvent component of the cleaning composition may be, for example, fractions (distillates) (petroleum, hydrogenated diesel) D100, isooctyl laurate, 2-ethylhexyl laurate, propylene glycol oligomers, unsaturated fatty acids, fatty acid esters, preferably esters such as saturated fatty acid alkyl esters, plasticizers, petroleum-based solvents such as naphthenes and paraffins, or combinations thereof, or any other organic solvent that dissolves ink residues.

[0073] The plasticizer reduces swelling of the rubber sheet 3'. A preferred plasticizer is diisononyl phthalate (DINP), which also improves the cleaning performance of the cleaning composition and reduces the amount of chemical residue on the blanket cylinder 3 after cleaning.

[0074] The propylene glycol oligomer may be, for example, tri(propylene glycol) propyl ether, tri(propylene glycol) methyl ether, tri(propylene glycol) butyl ether, propylene glycol propyl ether, tripropylene glycol, propylene glycol diacetate, ethylene glycol monophenyl ether, di(propylene glycol) propyl ether, di(propylene glycol) methyl ether, di(propylene glycol) dimethyl ether, or di(propylene glycol) butyl ether.

[0075] The fatty acid may be, for example, myristoleic acid, vaccenic acid, elaidic acid, linoelaidic acid, linoleic acid, palmitoleic acid, sapienic acid, oleic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, or docosahexaenoic acid.

[0076] The organic solvents used in the cleaning compositions are low VOC to avoid unwanted evaporation of the solvent.

[0077] The concentration of the organic solvent in the cleaning composition is 80 to 99.05% by weight, preferably 85 to 99.04% by weight, more preferably 90 to 99.025% by weight, and most preferably 95 to 99.9% by weight.

[0078] Other possible compounds included in the cleaning fluid with different properties may be, for example, aliphatic hydrocarbons for cleaning power, vegetable esters for cleaning power and reduced evaporation, corrosion inhibitors to prevent corrosion, and emulsifiers for emulsification with water.

[0079] In one embodiment, the cleaning composition comprises an unsaturated fatty acid, a propylene glycol oligomer, and a cellulosic solubilizer, preferably coconut diethanolamide.

[0080] In a further embodiment, the cleaning composition comprises distillate (petroleum, hydrogenated diesel) D100, isooctyl laurate, 2-ethylhexyl laurate, and a cellulosic solubilizer, preferably coconut diethanolamide.

[0081] In another embodiment, the cleaning composition comprises an ester, preferably a saturated fatty acid alkyl ester, a plasticizer, preferably diisononyl phthalate (DINP), and a cellulosic solubilizer, preferably coconut diethanolamide. The preferred weight concentrations of the ester, plasticizer, and cellulosic solubilizer in this embodiment are 30 to 50 weight percent. % ester, 40-60% plasticizer, 1-5% cellulose solubilizer. Most preferably, the cleaning composition comprises about 40% ester, about 57% plasticizer DINP, and about 3% coconut diethanolamide.

[0082] In yet a further embodiment, the cleaning composition comprises a petroleum based solvent, such as naphthene or paraffin, and a cellulosic solubilizer, preferably coconut diethanolamide.

[0083] The cleaning composition further comprises less than 2 wt.% water, such as less than 1 wt.% water, or such as less than 0.5 wt.% water. If the water content is more than 2 wt.%, the cleaning composition will evaporate and the concentration of the cellulosic solubilizer and organic solvent will be diluted, affecting the ability of the cleaning composition to dissolve ink and paper waste from the rubber sheet 3'.

[0084] The content of the organic solvent and the cellulosic material solubilizer in the cleaning composition according to the present disclosure is 98% by weight or more.

[0085] Pre-packaged cleaning rolls of the basic construction are per se known in the art and are described, for example, in US Pat. No. 5,368,157A.

[0086] According to the present disclosure, the cleaning cloth 13 is a material capable of absorbing liquid or solvent, such as a nonwoven fabric, adapted to be impregnated or soaked with the cleaning composition of the present disclosure before starting the cleaning process. Preferably, the cleaning cloth 13 is impregnated or soaked with the cleaning liquid of the present disclosure before being packaged and stored or transported. That is, the cleaning cloth 13 can be impregnated or soaked long before it is used in the cleaning process. Furthermore, the cleaning cloth 13 can be impregnated or soaked either before or after it is wrapped around the core 14.

[0087] The cleaning roll 12 shown in FIG. 3 is pre-packaged and stored until use in the cleaning process. The cleaning roll 12 is vacuum-packaged before the cleaning process begins until the bag 15 is broken. The vacuum-packaging process is typically performed by heat sealing. The multi-layer plastic film of the wrapping prevents the cleaning composition from evaporating. Additionally, the vacuum packaging of the roll 12 prevents the cleaning composition from migrating or diffusing through the cleaning fabric 13. Unwanted diffusion in the cleaning fabric 13 causes uneven distribution of the cleaning composition and therefore poor and uneven cleaning results.

[0088] Before starting the cleaning process, the cleaning roll 12 is removed from its packaging or bag 15 and placed on the mounting means 11 within the cleaning cassette 10, as shown in FIG.

[0089] The cleaning cassette 10 is then moved from an idle position, in which the cleaning fabric 13 is not in contact with the rubber sheet 3' of the cylinder 3, to an active position in which the cleaning cassette 10 is in contact with said rubber sheet 3' of the cylinder 3. The cleaning cassette 10 may also be brought into contact with other cylinders of the printing system, for example the impression cylinder 2. The cylinders 2, 3, 4, 5, 6 are rotated in the opposite direction to when the printing system is used for printing. In this way, the cleaning composition is transferred from the cleaning fabric 13 onto the rubber sheet 3' of the cylinder 3 and onto the remaining cylinders 2, 4, 5, 6 of the printing system 1.

[0090] Therefore, the cellulose contained in the cleaning composition impregnated in the cleaning cloth 13 The solubilizer for solubilizing the rubber material dissolves and removes paper residues and other water-soluble impurities, such as calcium carbonate, so there is no need to spray water onto the rubber sheet 3' before cleaning the system 1 with the cleaning cassette 10, and the spray bars 17a, 17b can be omitted.

[0091] Other components in the cleaning composition, such as the organic solvent(s), dissolve and remove, for example, residual ink on the cylinders 2,3,4,5.

[0092] Once the cleaning process is complete, the printing system 1 rotates the cylinders 2, 3, 4, 5 and damping rollers 6 in the printing direction, which is the opposite direction to that used in the cleaning procedure. The damping rollers 6 transfer water from the water bath 9 to the printing cylinders 2, 3, 4, 5, diluting the cleaning composition used to clean the printing cylinders 2, 3, 4, 5 and ultimately removing it from the printing system 1.

[0093] A pre-packaged roll 12 containing the cleaning composition of the present disclosure can be used in an already functioning printing system 1 that uses a cleaning cassette 10 as described and has spray devices 17a, 17b installed. The spray devices 17a, 17b can simply be switched off or closed and a new pre-packaged roll 12 can be attached to the attachment means 11, which will replace the spray step of the cleaning process.

[0094] In one embodiment (not shown), the cleaning composition may be sprayed onto a dry cleaning cloth prior to beginning the cleaning process, allowing the cleaning process to occur as described above without the need for a water spray step to dissolve the paper residue on the blanket cylinder.

[0095] In yet another embodiment (not shown), the cleaning composition may be sprayed directly onto the blanket cylinder, and the cleaning process can be carried out as described above without the need for a water spray step to dissolve the paper residue on the blanket cylinder. EXAMPLES

[0096] experiment The present inventors have surprisingly found that the addition of a cellulose solubilizer to a cleaning composition provides an effective alternative to the commonly used first cleaning step of spraying water onto the rubber sheet 3' of the printing cylinder 3. The cellulose solubilizer is selected from the group consisting of a hydrophilic surfactant, a superwetting agent, a C2-C6 alkanediol, a glycol ether, a compound containing an ethanolamine moiety, or combinations thereof. Exemplary cleaning compositions including a cellulose solubilizer are shown in Table 1a.

[0097] The new cleaning composition containing the cellulose solubilizer meets the requirements of the cleaning composition as shown by the experiments shown below. The preferred properties of the cleaning composition are ink solubility, low swelling of the rubber sheet 3' when contacted with the cleaning composition, and dissolution of the cellulose paper residue from the rubber sheet 3'. The results are presented in Tables 2 and 3 below and shown in Figures 5 and 6.

[0098] Example 1 The three organic solvents, fraction D100, isooctyl laurate and 2-ethylhexyl laurate, were used in cleaning composition A (CC A ) constitutes the

[0099] An example of a cleaning composition according to one embodiment is shown in Table 1a below. An exemplary cleaning composition according to one embodiment of the present disclosure contains three organic solvents (fraction D100, isolauric acid octyl, 2-ethylhexyl laurate) and a cellulosic solubilizer (coconut diethanolamide).

[0100] The concentration of the above three organic solvents is 95% by weight in total. The cellulosic solubilizer (CS) in the embodiment presented is coconut diethanolamide. The concentration of coconut diethanolamide is 5% by weight.

[0101] [Table 1]

[0102] [Table 2]

[0103] Experiment 1 - Swelling of rubber sheet 3' When a cleaning composition is used in a printing system, one of the requirements for the cleaning composition is that it does not swell the rubber sheet 3' on the blanket cylinder 3. If the rubber sheet 3' swells too much, the pressure between the rubber sheet 3' on the blanket cylinder 3 and the impression cylinder 2 becomes too high, resulting in, for example, poor quality of the printed matter.

[0104] The test is carried out by taking a piece of rubber material used in the rubber sheet of the printing system and placing it on a flat surface (not shown). The thickness of the rubber material is about 2 mm. A bottomless hollow beaker is placed upright on the rubber sheet material and the cleaning composition to be tested (not shown) is placed inside the beaker. The cleaning composition is left in the beaker at a given temperature (here 40° C.) and for a given time (here 24 hours). The thickness of the rubber sheet material is measured outside the beaker to serve as a reference height. The height of the area of ​​the rubber sheet material that was in contact with the cleaning composition is also measured. Finally, the difference between the two heights is calculated as a percentage of the reference height.

[0105] Cleaning composition CC according to Table 1 A and cleaning compositions according to the embodiments of Table 1a The test results of the product are presented in Table 2 below. B and CC with added cellulosic material solubilizer (coconut diethanolamide). B The test results are also presented in Table 2 below. Cleaning Composition CC B contains unsaturated fatty acids and propylene glycol oligomers.

[0106] The cleaning compositions were left in contact with the rubber sheet material for 24 hours at 40° C. First, cleaning composition CC A and C.C. B The swelling index of the rubber sheet material at that time corresponded to 1.42 and 1.97, respectively, as can be seen from Table 2. CC A After adding 5% coconut diethanolamide to CC, the swelling degree increased slightly to 1.59%. B After adding 5% coconut diethanolamide to the rubber, the swelling index increased to 2.59%. Both of these values ​​(1.59 and 2.59) are below the threshold for approving the swelling of rubber sheeting.

[0107] [Table 3]

[0108] Experiment 2 - Ink solubility The addition of a water substitute must not reduce the ink solubility of the cleaning composition, as this would risk the cleaning composition being unable to efficiently remove residual ink from the printing cylinder during the cleaning process.

[0109] The results of the ink solubility test are shown in Figure 5. On the left side of Figure 5, two beakers B1 and B2 contain cleaning composition CC A The leftmost beaker B1 also contains 5% cellulose solubilizer (coconut diethanolamide). The two rightmost beakers B3 and B4 contain cleaning composition CC B Contains CC B Of the two beakers containing cellulose, the left one, beaker B3, contains 5% cellulose solubilizer (coconut diethanolamide).

[0110] In performing the test, a substrate coated with red ink is submerged in a beaker containing the cleaning composition. The substrate is then removed from the beaker and transferred to a paper towel 18. Solubility is assessed visually by observing the amount of ink on the substrate that is dissolved by the cleaning composition.

[0111] In FIG. 5, the substrates S1, S2, S3, S4 are placed in front of the beaker in which they were placed. Cleaning composition CC A Of the two substrates immersed in the cleaning composition CC 500, the left one, S1, has more dissolved ink than the right one, S2. A However, cleaning composition CC does not contain the cellulose-based solubilizer coconut diethanolamide. A This means that it has a higher solubility than

[0112] On the right side of FIG. 5, cleaning composition CC 500 containing 5% coconut diethanolamide B From the substrate S3 submerged in the water (the left substrate S3 of the two substrates on the right side of Figure 5), Therefore, the cleaning composition CC containing 5% coconut diethanolamide was used. B Even in this case, the ink solubility was higher than in the cleaning composition that did not contain 5% coconut diethanolamide.

[0113] Experiment 3 - Paper residue cleaning test To evaluate the dissolution of paper residue from the rubber sheet material, a paper residue and ink cleaning test was conducted.

[0114] An unwashed rubber sheet blanket 19 of the same type as used as rubber sheet 3', covered with ink and paper residue, was placed on a flat surface. Cleaning compositions containing different concentrations of cellulosic solubilizers (coconut diethanolamide and triethanolamine) were applied onto different fabrics C1, C2, C3, C4, C5, which were subsequently contacted with the soiled rubber sheet blanket 19. The fabrics C1, C2, C3, C4, C5 were then manually dragged over the surface five times.

[0115] The results shown in Figure 6 indicate the amount of color and paper fibers that fabrics C1, C2, C3, C4, and C5 removed from the rubber sheet blanket material. The darker the fabric, the more color and paper residue was dissolved and removed from the rubber sheet blanket material. The results of this experiment are shown in Figure 6. Table 3 shows the different water substitutes that were tested in the cleaning test experiment.

[0116] [Table 4]

[0117] The above results show that a concentration of 5 wt% cellulosic solubilizer gave the best results. The results of tests WT1 and WT3 show that the darker fabrics (C1 and C3, respectively) dissolved more ink and paper residue than the other fabrics after repeated washing of the rubber sheet 19. The control test WT2 has the least dark fabric C2 and therefore dissolved the least ink and paper residue among all fabrics C1, C2, C3, C4, and C5. Thus, the cleaning composition according to the present disclosure performs better in the wash tests.

[0118] Finally, although the inventive concept has been described above with reference to specific embodiments, it is not intended that the invention be limited to the specific form set forth herein. Rather, the invention is limited only by the appended claims, and other embodiments than those specifically described above are possible within the scope of these appended claims.

Claims

1. 1. A roll of cleaning cloth for cleaning a print cylinder of a printing system, comprising: the cleaning cloth is impregnated with a cleaning composition, the cleaning composition comprising an organic solvent which is an ester and a cellulose solubilizer which is a glycol ether; the glycol ether is selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, phenoxyethanol, pentaethylene glycol monododecyl ether and alkylene polyglycol ethers; the cleaning composition comprises less than 2% by weight of water; The content of the cellulose solubilizer is 0.1 to 5% by weight, The content of the organic solvent is 95 to 99.9% by weight.

2. 2. The roll of claim 1, wherein the cleaning fabric (13) is wrapped around a core (14) to form the roll (12).

3. 3. The roll of claim 1 or 2, wherein the roll (12) is inserted into a removable sealing bag (15) configured to seal around the roll (12) of cleaning cloth (13) to prevent the cleaning composition from evaporating prior to use.

4. 4. A roll according to claim 3, wherein the sealing bag (15) is made of a multi-layer plastic film.

5. 5. The roll of claim 3 or 4, wherein the roll (12) of cleaning cloth (13) is vacuum packed in the sealed bag (15).

6. 1. A cleaning cloth for cleaning a printing cylinder of a printing system, the cleaning cloth being impregnated with a cleaning composition comprising an organic solvent that is an ester and a cellulose solubilizer that is a glycol ether, the cellulose solubilizer including an ethanolamine moiety; the glycol ether is selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, phenoxyethanol, pentaethylene glycol monododecyl ether and alkylene polyglycol ethers; the cleaning composition comprises less than 2% by weight of water; The content of the cellulose solubilizer is 0.1 to 5% by weight, The cleaning cloth has an organic solvent content of 95 to 99.9% by weight.

7. A method for cleaning a printing cylinder of a printing system using a roll according to any one of claims 1 to 5, comprising the steps of: unrolling at least a portion of a cleaning cloth (13) impregnated with a cleaning composition comprising an organic solvent which is an ester and a cellulose solubilizer which is a glycol ether from the roll (12); placing said portion of said cleaning cloth in contact with a print cylinder; Equipped with the glycol ether is selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, phenoxyethanol, pentaethylene glycol monododecyl ether and alkylene polyglycol ethers; the cleaning composition comprises less than 2% by weight of water; The content of the cellulose solubilizer is 0.1 to 5% by weight, The content of the organic solvent is 95 to 99.9% by weight.

8. A method for forming the roll of any one of claims 1 to 5, comprising the steps of: impregnating a cleaning cloth (13) with a cleaning composition comprising an organic solvent which is an ester and a cellulose solubilizer which is a glycol ether; wrapping the cleaning cloth (13) around a core (14) to form a roll (12); Inserting said roll (12) into a sealable bag (15) in which it is vacuum packed; Equipped with the glycol ether is selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, dipropylene glycol methyl ether, phenoxyethanol, pentaethylene glycol monododecyl ether and alkylene polyglycol ethers; the cleaning composition comprises less than 2% by weight of water; The content of the cellulose solubilizer is 0.1 to 5% by weight, The content of the organic solvent is 95 to 99.9% by weight.

9. 9. The method of claim 8, wherein the cleaning cloth (13) is impregnated with the cleaning composition after being wrapped around the core (14).

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