Cleaning cloth roll and related devices and methods

Abstract

A roll of cleaning cloth (13) is used to clean the print cylinders of a printing system. The cleaning cloth (13) is impregnated with a cleaning composition containing an organic solvent and a cellulose solubilizer. The roll may be wrapped around a core (14) and inserted into a removable sealable bag (15) configured to seal around the roll of cleaning cloth (13) (12) to prevent the cleaning composition from evaporating prior to use. [Selection diagram] Figure 4

Description

[Technical Field]

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

[0002] In order for print cylinders 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] Cleaning cloths are often pre-impregnated with a cleaning composition 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 debris is difficult to dissolve with the cleaning composition, and therefore the paper residue needs to be removed from the cylinder before the cleaning process using the cleaning cloth can begin. Therefore, it is common practice to spray water onto the printing cylinder with a spray bar or spray nozzle installed in the printing system. For example, U.S. Patent Application Publication No. 2005250659A1 describes how water can be sprayed onto the cylinder of a printing system to remove dust and paper residue.

[0004] However, the spray bars, nozzles, and water lines that carry water to the nozzles are prone to clogging due to the hostile environment within the printing system, which contains paper debris, residual ink, and other contaminants that can clog the spray devices. Lime in the water used can also cause clogging.

[0005] Examples of prior art arrangements which attempt to solve the problem of clogged 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, U.S. Pat. No. 5,340,495 A and GB 1,365,464 A. From the above, it can be seen that there is room for improvement with respect 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] British 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 alleviates the problems discussed above. This object is achieved by the techniques set out in the accompanying independent claims, with preferred embodiments defined in the associated dependent claims. [Means for solving the problem]

[0008] The present invention is based—among other things—on the technical concept that if the cleaning liquid, also referred to herein as a cleaning composition, itself can dissolve cellulosic paper residue, the step of spraying water on the printing cylinder can be eliminated. The inventors surprisingly discovered that by adding a cellulosic solubilizer, preferably a non-aqueous cellulosic solubilizer, also referred to herein as a water substitute, to the cleaning liquid, the paper residue is dissolved from the printing cylinder. Thus, the initial cleaning step, i.e., spraying water, can be eliminated from the printing system cleaning process. Because many printing systems require cleaning multiple times daily, the cleaning composition of the present invention saves time. Furthermore, the labor-intensive process of cleaning and / or replacing clogged water pipes, spray bars, or nozzles is no longer a problem.

[0009] In a first aspect, a cleaning cloth roll adapted and configured for cleaning print cylinders of a printing system is provided. The cleaning cloth is impregnated with a cleaning composition comprising 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. The organic solvent provides the cleaning composition with the ability to dissolve and remove ink from the print cylinder.

[0010] In one embodiment, the cleaning composition contains less than 10% by weight of water, preferably less than 5% by weight of water. In another embodiment, the cleaning composition contains less than 2% by weight of water. The presence of more than 2% by weight of water in the cleaning composition can 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 this regard, the ethanolamine moiety is defined as shown in Formula I. The ethanolamine moiety provides a hydrophilic portion to the solubilizer, facilitating 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 an ethanolamine moiety is ethanolamide. The ethanolamide dissolves paper residue and other water-soluble impurities adhering to the printing cylinder. Furthermore, the swelling of rubber in the printing system due to contact with the cleaning composition can be kept within an acceptable range when 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 a cleaning composition with favorable ink solubility in addition to dissolving paper residue from the printing cylinder. It is likely that coconut diethanolamide effectively absorbs moisture from the environment, thereby efficiently dissolving paper, which in turn has the effect of destroying 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. 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 cylinder.

[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 able to dissolve paper residue and other water-soluble contaminants from the printing cylinder.

[0018] In another embodiment, the cellulose solubilizer is a C2-C6 alkanediol. The hydroxyl groups of the C2-C6 alkanediol make the compound hydrophilic, enabling it to dissolve paper residue 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 with 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 a low concentration of the superwetting agent is required to dissolve the paper residue. Thus, the concentration of the superwetting agent can be as low as 0.05 to 0.1 wt. %. Using a low concentration of cellulosic solubilizer is preferred because it allows the amount of organic solvent that provides ink solubility to the cleaning composition to be kept at a high level.

[0022] In another embodiment, the content of the cellulose solubilizer in the cleaning composition is 0.05 to 20 wt %, preferably 0.075 to 10 wt %, and most preferably 0.1 to 5 wt %. 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 wt %, the ink solubility of the cleaning composition will decrease. If the solubilizer concentration is too low, i.e., less than 0.05 wt %, the cleaning composition will not adequately dissolve and remove paper residue.

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

[0024] In yet another embodiment, the cleaning cloth 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, when the cleaning cloth is wound around the core, it is easier to handle and more protected.

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

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

[0027] In a second aspect, a cleaning composition is provided that is adapted and configured to clean a print cylinder of a printing system. The cleaning composition includes an organic solvent and a cellulose solubilizer. The cleaning composition can be transferred, e.g., sprayed, onto a cleaning cloth or print 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% by weight of water, preferably less than 5% by weight of water.

[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 this regard, the ethanolamine moiety is defined as shown in Formula I. The ethanolamine moiety provides a hydrophilic portion to the solubilizer, facilitating 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 an ethanolamine moiety is ethanolamide. The ethanolamide dissolves paper residue and other water-soluble impurities adhering to the printing cylinder. Furthermore, swelling of rubber in the printing system due to 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. 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 cylinder.

[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 are therefore able to dissolve paper residue 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, enabling it to dissolve paper residue and other water-soluble soil particles.

[0037] In yet another embodiment, the C2-C6 alkanediol in the cleaning composition is ethylene glycol (ethane-1,2-diol), a C2 alkanediol with 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 the superwetting agent are required to dissolve the paper residue. Thus, the concentration of the superwetting agent can be as low as 0.05 to 0.1 wt. %. Using a low concentration of a non-aqueous cellulosic solubilizer is preferred because it allows the amount of organic solvent that provides ink solubility to the cleaning composition to 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 wt %, preferably 0.075 to 10 wt %, and most preferably 0.1 to 5 wt %. 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 wt %, the ink solubility of the cleaning composition will decrease. If the solubilizer concentration is too low, i.e., less than 0.05 wt %, the cleaning composition will not adequately dissolve and remove paper residue.

[0041] In one embodiment, the organic solvent content of the cleaning composition is 80 to 99.05 wt. %, preferably 90 to 99.025 wt. %, and most preferably 95 to 99.9 wt. The concentration of the organic solvent must be balanced with the concentration of the cellulosic solubilizer. If the organic solvent concentration is higher than 99.9 wt. %, the concentration of the cellulose solubilizer will be too low, and the cleaning composition will not be able to dissolve paper residue from the printing cylinder. If the organic solvent concentration is too low, i.e., less than 80 wt. %, the cleaning composition will not adequately dissolve and remove 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% by weight of water, preferably less than 5% by weight of water.

[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 cloth with a cleaning composition, wrapping the cleaning cloth 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 wound around a core.The advantage of this is that when the cleaning cloth is wound around a core, the cleaning cloth may be easier to handle and be more easily impregnated.For example, the cleaning cloth wound around a core can be placed in a sealable bag and impregnated while it is 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 explanation of the drawings]

[0050] DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention are described below. Reference is made to the accompanying drawings, which illustrate non-limiting examples of how the concepts of the present invention may be implemented.

[0051] [Figure 1] FIG. 1 shows a cross-section of a typical printing system comprising a cylinder and a cleaning cassette arrangement with a cleaning cloth roll and a spray nozzle bar. [Figure 2] FIG. 2 shows an enlarged portion of FIG. [Figure 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. [Figure 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 INVENTION

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

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

[0054] 1 and 2 show spray devices 17a and 17b used in the current cleaning system. 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, with spray nozzles located at either position 17a or position 17b. The spray devices 17a and 17b are positioned 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 positioned inside the cleaning cassette 10 facing the blanket cylinder 3, or adjacent to the cleaning cassette 10 facing the blanket cylinder 3.

[0055] FIG. 2 shows a cleaning cassette 10 of the printing system 1 shown in FIG. 1. The cleaning cassette 10 includes a cleaning roll 12 that includes a bobbin or core 14. A cleaning cloth 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 FIGS. 1 and 2 further includes a collection roller 16.

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

[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 suitable plastic film 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 shown good results in practical tests. The thickness of the sealed 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] Next, the printing operation and cleaning of printing system 1 will be described in more detail. Referring to FIG. 1, when printing system 1 is performing a printing operation, water is transported toward the cylinders via damping roller 6, which collects water from damping source 9. In this way, the water arrives and resides on the non-pressure surface generated between cylinders 2, 3, and 4. Ink is then transported toward cylinders 3, 4, and 5 by ink roller 5, which collects ink from ink source 8. The print is then transferred to blanket cylinder 3 and a material, such as paper. The material to receive the print, such as paper, is placed between rubber sheet 3' on blanket cylinder 3 and impression cylinder 2. Here, the printing operation occurs, and the print is transferred from rubber sheet 3' to the material. The cylinder and roller configurations shown and described herein are merely one example of a printing system configuration.

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

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

[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 includes at least one organic solvent for diluting and / or dissolving residual ink and at least one cellulose solubilizer configured to dissolve cellulosic materials, such as wastepaper, from cylinders 2, 3, 4, and 5. Therefore, the water spraying step is no longer necessary, meaning that spray devices 17a and 17b can be omitted. The cellulosic solubilizer is intended to dissolve water-soluble cellulosic wastepaper. However, adding water to the cleaning composition would evaporate the water, and the cleaning composition would lose its ability to dissolve water-soluble impurities. Replacing the water spraying step by adding water to the cleaning composition is therefore not an option. Instead, the cellulosic solubilizer should be low in volatile organic compounds (VOCs). The following list of possible compounds from which the cellulosic solubilizer can be selected all has low VOCs.

[0064] The concentration of the cellulosic solubilizer in the cleaning composition is 0.05 to 20 wt%, preferably 0.06 to 15 wt%, more preferably 0.075 to 10 wt%, and most preferably 0.1 to 5 wt%. 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 wt%, the ink solubility of the cleaning composition will decrease. If the solubilizer concentration is too low, i.e., less than 0.05 wt%, the cleaning composition will not adequately dissolve and remove paper residue.

[0065] The cellulosic solubilizer can 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, and amine oxides. These superwetting agents are strong wetting agents, meaning that even low concentrations are sufficient to effectively dissolve cellulosic materials. The concentration of the superwetting agent in the cleaning composition can 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 material solubilizer include, 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 may be, for example, an alkanolamine or alkanolamide, preferably ethanolamine or ethanolamide, most preferably triethanolamine or coconut diethanolamide.

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

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

[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 liquid with different properties may be, for example, aliphatic hydrocarbons for cleaning power, vegetable esters for cleaning power and reduced evaporation, corrosion inhibitors for corrosion prevention, 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 30-50% by weight of the ester, 40-60% by weight of the plasticizer, and 1-5% by weight of the cellulosic solubilizer. Most preferably, the cleaning composition comprises about 40% by weight of the ester, about 57% by weight of the plasticizer DINP, and about 3% by weight of 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 greater than 2 wt.%, the cleaning composition will evaporate, diluting the concentration of the cellulosic solubilizer and organic solvent, which will affect the ability of the cleaning composition to dissolve ink and paper debris 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 known per se 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 the cleaning process begins. Preferably, the cleaning cloth 13 is impregnated or soaked with the cleaning composition of the present disclosure before being packaged for storage or transportation. 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 until the bag 15 is ruptured before the cleaning process begins. The vacuum-packaging process is typically accomplished 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 cloth 13. Unwanted diffusion in the cleaning cloth 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 in the cleaning cassette 10, as shown in FIG.

[0089] The cleaning cassette 10 is then moved from an idle position, in which the cleaning cloth 13 is not in contact with the rubber sheet 3' of the cylinder 3, to an active position, in which the cleaning cloth 13 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, such as the impression cylinder 2. The cylinders 2, 3, 4, 5, and 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 cloth 13 onto the rubber sheet 3' of the cylinder 3 and onto the remaining cylinders 2, 4, 5, and 6 of the printing system 1.

[0090] Therefore, the cellulosic solubilizer contained in the cleaning composition impregnated in the cleaning cloth 13 dissolves and removes paper residue and other water-soluble impurities, such as calcium carbonate, eliminating the need to spray water onto the rubber sheet 3' before using the cleaning cassette 10 to clean the system 1, and thus eliminating the need for the spray bars 17a and 17b.

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

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

[0096] experiment The present inventors have surprisingly discovered that adding 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 a combination thereof. Exemplary cleaning compositions containing a cellulose solubilizer are shown in Table 1a.

[0097] The new cleaning composition containing a cellulose solubilizer meets the requirements for a cleaning composition as shown by the experiments below. The desirable properties of the cleaning composition are ink solubility, low swelling of the rubber sheet 3' upon contact with the cleaning composition, and dissolution of 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 includes three organic solvents (fraction D100, isooctyl laurate, 2-ethylhexyl laurate) and a cellulosic solubilizer (coconut diethanolamide).

[0100] The total concentration of the three organic solvents is 95% by weight. In the present embodiment, the cellulosic solubilizer (CS) 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 performed by taking a portion of the rubber material used in the printing system's rubber sheet and placing it on a flat surface (not shown). The rubber material is approximately 2 mm thick. A bottomless, hollow beaker is placed upright on top of the rubber sheet, and the cleaning composition to be tested (not shown) is poured into it. The cleaning composition is left in the beaker at a predetermined temperature (here, 40°C) and for a predetermined time (here, 24 hours). The thickness of the rubber sheet is measured outside the beaker to serve as a reference height. The height of the area of ​​the rubber sheet that came into 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 the test results for the cleaning composition according to the embodiment of Table 1a are presented in Table 2 below. Alternative cleaning composition CC 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. A and CC B The test was conducted without adding a cellulosic solubilizer. As can be seen from Table 2, the swelling index of the rubber sheet material at that time corresponded to 1.42 and 1.97, respectively. CC A After adding 5% coconut diethanolamide to CC, the swelling degree increased slightly to 1.59%. BAfter adding 5% coconut diethanolamide, 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 effectively 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 beaker B3 contains 5% cellulose solubilizer (coconut diethanolamide).

[0110] To perform 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 Figure 5, substrates S1, S2, S3, S4 are placed in front of the beakers they came in. Cleaning composition CC A Of the two substrates immersed in the cleaning composition CC containing 5% coconut diethanolamide, the left substrate S1 has more ink dissolved than the right substrate S2.A However, cleaning composition CC does not contain coconut diethanolamide, a cellulose-based solubilizer. A This means that it has a higher solubility than

[0112] On the right side of Figure 5, cleaning composition CC containing 5% coconut diethanolamide B Substrate S3 (the left one of the two substrates on the right side in Figure 5) submerged in water had more ink dissolved. Therefore, the cleaning composition CC containing 5% coconut diethanolamide was B Even with the addition of 5% coconut diethanolamide, the ink solubility was higher than in the cleaning composition without the addition of 5% coconut diethanolamide.

[0113] Experiment 3 - Paper residue cleaning test To evaluate the dissolution of paper residue from 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 to different fabrics C1, C2, C3, C4, and C5, which were then contacted with the soiled rubber sheet blanket 19. The fabrics C1, C2, C3, C4, and 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 color, the more color and paper residue was dissolved and removed from the rubber sheet material. The results of this experiment are shown in Figure 6. Table 3 lists the different water substitutes tested in the wash test experiment.

[0116] [Table 4]

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

[0118] Finally, although the inventive concept has been described above with reference to specific embodiments, the invention is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the appended claims, and other embodiments besides the specific ones described above are also 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, a plasticizer, and a cellulose solubilizer which is a glycol ether; the roll being inserted into a removable sealable pouch configured to seal around the roll of cleaning cloth to prevent evaporation of the cleaning composition prior to use; The sealed bag is tubular and made of a multi-layer plastic film.

2. 10. The roll of claim 1, wherein the cleaning composition comprises less than 10% by weight of water.

3. 2. The roll according to claim 1, wherein the content of the cellulose solubilizer in the cleaning composition is 0.05 to 20% by weight.

4. 2. The roll according to claim 1, wherein the content of the organic solvent is 80 to 99.05% by weight.

5. 2. The roll of claim 1, wherein the cleaning cloth is wrapped around a core to form the roll.

6. 10. The roll of claim 1, wherein the roll of cleaning cloth is vacuum packaged within the sealed bag.

7. 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, a plasticizer, and a cellulose solubilizer that is a glycol ether.

8. 10. A method for cleaning a print cylinder of a roll-based printing system according to claim 1, comprising: removing the sealed bags from the roll; unrolling from the roll at least a portion of a cleaning cloth impregnated with a cleaning composition comprising an organic solvent that is an ester, a plasticizer, and a cellulose solubilizer that is a glycol ether; placing said portion of said cleaning cloth in contact with a print cylinder; A method for providing

9. 10. A method of forming the roll of claim 1, comprising: impregnating a cleaning cloth with a cleaning composition comprising an organic solvent which is an ester, a plasticizer, and a cellulose solubilizer which is a glycol ether; wrapping the cleaning cloth around a core to form a roll; inserting the roll into a sealable bag which is vacuum packed; A method for providing

10. 10. The method of claim 9, wherein the cleaning cloth is impregnated with the cleaning composition after being wrapped around the core.

Images