JPS58104796A - Method of washing and regenerating printing screen - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]! A privilege! This application was filed on the same date, fl:, Gary M., Va.
Related to the application entitled "Printing Screen Cleaning and Recycling Composition" of laaek invention.

BACKGROUND OF THE INVENTION Screen printing is a well-established practical industry.
Essentially, printing screens are the locally applied dye pastes or inks used in reproducing images from a screen to which various patterns, artwork or print marks are applied by a fairly permanent emulsion onto the screen. ing. Since the emulsion surrounding the image area of the printed screen is resistant to ink, the printing process 1 applies the ink through the screen for image reproduction.
It will not be removed inside. This property of the emulsion being impervious to inks and cleaning solvents makes removal of the emulsion from the printed screen even more difficult.
Printing screens are usually made from silk, synthetic fibers, or metal materials, and are commonly reused in actual screen printing. This includes a cleaning step, in which the ink residue from the round printing operation is removed from the screen, washed, and the screen is stored and reused. During ink removal, it is sometimes important not to affect the emulsion areas applied to the screen.

Rather, modern screen printing has developed complex ink or dye formulations that are often difficult to remove. Agents suitable for washing ink from the screen will also act on the underlying emulsion. Screen printing thus involves a balanced chemical process in which the screen is created from semi-permanent to fully permanent emulsion artwork, and the emulsion areas resist ink attack and reproduce the ink image. . In such operations, the screens are stored and/or cleaned repeatedly before rounding for the next use. It is also important to be able to regenerate the screen, in which case the ink image and/or fusion areas are removed with a different type of screen regeneration solution or agent.

Typically, a commercial screen printing shop cleans or recycles a large number of screens each day, and rounding screen cleaning machines or recycle systems are used for this purpose. Such cleaning machines or regeneration systems typically use recycled solvents and
A synthetic or metal screen is introduced there to clean or regenerate the green mold as required. The first commercial operation involves manual cleaning using various solvents or caustics.
ii #danku encompasses rebirth. During washing or recycling,
Screen printers often come into contact with chemicals and bath additives. A number of solvents or chemicals are used for screen cleaning and regeneration. The three most commonly used agents are classified as aliphatic hydrocarbons, aromatic hydrocarbons, and oxygenated solvents, and sometimes chlorinated solvents are also used. Although aliphatic hydrocarbons are commonly referred to as "niel spirits," these aliphatic solvents are actually composed of a mixture of straight-chain and/or branched-chain saturated hydrocarbons.

As the molecular weight or number of carbon atoms increases, the boiling point of the solvent increases. As the boiling point increases, the solvent becomes difficult to evaporate, so excessively high boiling point aliphatic hydrogen is desirable for use in screen cleaning. Aromatic hydrocarbon bath agents include cyclic hydrocarbons containing benzene rings. Generally, aromatic hydrocarbons are more flammable than aliphatic solvents, but have greater solvation power, and similarly, the higher the molecular weight of aromatic hydrocarbons, the higher the boiling point. While it is a rather non-polar hydrocarbon, the fIIIA-forming solvent is more polar. Typical tanning solvents are those containing hydroxyl and carbonyl groups, and many of them have considerable solubility in water.

Other solvents include chlorinated solvents that are fully or partially chlorinated with nine hydrocarbons and rarely used Freon-capped fluorinated hydrocarbons.

Thus, today's printers are dealing with a large number of solvents used for screen cleaning and recycling. In the past, little consideration was given to the dangers to health and safety that printers and workers desired, and bath salts were used without incident when running. Nowadays, federal and state laws require that solvents meet material safety standards, that solvents generally must avoid prolonged or repeated contact with skin, and that in many cases solvents are flammable and therefore subject to high heat. Additionally, firefighting suits often require off-layer storage of solvents. Also, OS HA (0ecup
at1onal 8afty and Health
Administration) has various restrictions on the use of solvents, many of which may no longer be usable. Furthermore, the known processes require high temperature regeneration systems to clean or regenerate the printing screens, but such systems are no longer unavoidably unclean and dangerous. In researching suitable screen cleaning and regeneration baths or agents, do not use hazardous flammable solvents.
(Departments of Transport
ion) It is desirable to provide cleaning and rejuvenation compositions that do not require a red label and are completely or essentially biodegradable. Another highly desirable objective is to make available industrial cleaning and reclamation products with high threshold values (TLV).
) indicates that the airborne particles produced by such products provide greater respiratory safety.
Taste.

The above technical background is now in its practical entirety as seen by those skilled in the art from the standpoint of cleaning and regeneration processes in the screen printing industry.

In addition, there are patents that are believed to be relevant to the main aspects of the invention at the time of writing this application. Below is a list of prior patents that may be helpful in understanding this patent, but this does not mean that it is complete or that there are no related patents or documents. No. 2 U.S. Patent No. 2,
No. 780,168, No. 3,459,594, $5.5
No. 11.657, 1llt5, 615, 827,! I
No. 5,642,567, No. 3.67! t, No. 099, No. 6,679,479, ji3,7 Ll 6.6
No. 91, No. 5,737,386, 1L5.764.5
No. 84, No. 6. /' No. 89,007, j16,79
No. 6.602, #IS, No. 928,065, No. 5,95
No. 5,552, $4,024,085, Ji4,05
No. 5,515 O! Act 4, 07 Ll, No. 203. It must be said that these patents were published for the purpose of understanding the present invention, and are also derived from dissimilar technology. Therefore, in any event, the nine listed here do not currently encourage the state of printing screen cleaning or recycling technology.

It was stated that there is a need for a printing, cleaning, or regenerating composition that is effective in a wide variety of fields. Moreover, the compositions are highly effective.

A Cost of the Invention The present invention generally relates to a printing screen cleaning process that is effective for solvating or decomposing inks used in the printing industry. This method is wide
It functions by ink cleaning compositions that not only lubricate or decompose h11@ in the print-in, but also have a high flash point or no flash point, and have excellent compatibility and high threshold values. Therefore, the health and safety of screen printers or workers in Ren's industry is greatly improved by this method. In addition, the present invention can act synergistically to remove ink and sensitize the printing screen to remove the ink and lusion that is printed on the screen □ Cleaning and Recycling provide a method. Also, generally 舊−°、・
,,,,.

In other words, the present invention provides a method for cleaning or cleaning and recycling a circular printing screen made from silk, textile, metal or any type thereof without damaging it for immediate storage or reuse. includes.

The method of the present invention is essentially based on N-methyl-2-pyrrolene (hereinafter sometimes abbreviated as rNMPJ) disclosed in the co-pending application entitled "Printing Screen Cleaning and Reclamation Compositions" by Gary M. and Valasek. ), using a unique composition consisting of an oxygenated solvent and a surfactant. As reported therein, these essential non-aqueous systems solubilize and degrade a wide variety of polymeric and other inks widely used in the modern screen printing industry. This composition has been found to penetrate the ink, emulsify the ink, and prevent ink redeposition during ink removal from common printing screens. Additionally, a composition consisting of NMP, an oxygenated solvent, and a surfactant can be used to effectively clean the screen and, if necessary, to sensitize the cleaned printed screen for subsequent emulsion removal. It turns out that it has to be non-aqueous.

In the present invention, the screen cleaning and regeneration method is NMP.
, a concentrated liquid consisting of an oxygenated solvent and a surfactant system (hereinafter abbreviated as "NMP protocol") is sprayed onto the screen surface to form a rounding solution that allows for decomposition. This is done by consonant for a sufficient period of time. Then rinse the interior with water and remove from the screen.

By this method, the ink is broken down into foreground lines that can be completely removed by a high pressure, low volume water spray. According to the method of the invention, the NMPIIIJll liquid is sprayed onto the surface during screen-in. By spraying with a NMP concentrate zero-closing spray, it is possible to use extremely low amounts and still accomplish amazingly great decomposition. Also, after one ink wash with NMP concentrate 1K, the printed emulsion was found to be sensitized and rounded to 11K, suitable for removal from the screen with a materate-containing emulsion remover. In this way, it is possible to completely regenerate the screen. If you need more after that,
Residue or "yeast" in the image ink (commercially used trowel) t-oxygenated solvent containing caustic alkali IJ#i
[can be removed by According to the above order,
Provides the entire process of cleaning and regeneration of nuclear power plant IjIIUt screens.

With the development of the back-weight technology of the present invention, conventional screen cleaning and regeneration methods have been replaced by mineral hot solvent and alkaline methods. The present invention obviates the need for such a heat flow method and the health risks resulting therefrom. In other words,
The invention can be practiced at ambient or room temperature conditions. In this important respect, it is highly unexpected and distinct from the prior art that a cleaning and regeneration process can be operated at such low temperatures, even at ambient temperatures, and be effective in removing a wide variety of ink compositions. It seems that this is not something that can be accomplished easily. Furthermore, while the use of pyrrolidone derivatives, including alkylpyrrolidones, in cleaning compositions has been disclosed in prior patents, the use of pyrrolidone derivatives in compositions or methods for removing screen printing ink compositions is There is no suggestion of using either. Furthermore, even though pyrrolidones have been suggested in dissimilar art, they are generally used in aqueous systems as opposed to the essentially non-aqueous concentrates of the present invention.

Also, in the screen printing industry, the use of N-methyl-2-pyrrolidone in combination with oxygenated solvents and surfactants is essential for achieving optimal effectiveness in the rounding of nuclear power plants. , provides a non-toxic, biodegradable and very safe cleaning composition, as also achieved by the method of the present invention, which is still capable of producing highly desirable cleaning and synergistic rejuvenating effects. It has not been suggested in the past to do so.

DETAILED DESCRIPTION OF THE INVENTION As noted above, the method of the present invention comprises N-methyl-2-biD&I
In order to use a composition consisting of a Pn, 1lIllA solvent and a surfactant. The oxygenated solvent in a preferred composition is a combination of detylurosolp and Schiff 4 dF nanonones:1. □These preferred oxygenated solvents include glycol ethers, alcohols and
□ and ketones. Other types of oxygenated solvents that can be used include esters and ethers, and mixtures thereof. Preferably, the surfactant is selected from the group consisting of nonionic or -ionic surfactants, mixtures thereof, and specific examples of nonionic surfactants are available from Rohm and Hass. Octylphenoxy (polyethoxy) ethanol sold under the trademark TRITONX-114 and GAFACR from General Aniline and Tuilm, Inc.
It is an organic phosphoric acid ester sold under the trademark P-710. Additionally, examples of oxygenated solvents from glycol ethers that may be used include methyl rosolde, hexyl cellosolve, cellosolve solvent, methyl calpitol, calgitol solvent, butyl calpitol, hexyl carudol, and the like. Ru. Examples of other ketones include methyl ethyl ketone, methyl isobutyl ketone, methylinoyl ketone, methyl ethyl ketone, and isobutyl! Included are tylketones, isophones, diacetone alcohols, acetone, and the like. Examples of other ethers include butyrolactone, diethylcarpitol and diethylcarpitol, and others. Examples of esters include butylactate, butyl acetate, butyl cal-C-toll acetate, carpitol acetate, butyl cellosol deacetate, cellosolve acetate, 2-ethylhexyl acetate, amyl acetate, methyl selonol acetate, formate, and others. Ru. Examples of alcohols include amyl alcohol, butyl alcohol, furfurol alcohol, 2-butyne-1,4-diol, tetrahydrofurfurol alcohol, and others. I! According to the broad principal components of the present invention, oxygenated solvents from the above classes have the most desirable biodegradability, least flammability and high moth-resistant limits meeting or exceeding health and safety standards. Depending on the rounding obtained, the oxygenated solvent is suitable for use depending on the required solubilizing capacity. However, in accordance with the preferred principal components of the invention as described above, there are specific embodiments that meet all criteria of the most preferred aspect of the invention. Generally speaking, the oxygenated solvent promotes the low viscosity AS solvation properties of the NMP and aids in the dispersion of the NMP to solubilize or degrade the ink composition. NMP if necessary
becomes t-9 water activity. Therefore, the combination of NMP and oxygenated solvents has a unique water activity as well as an interaction with the organic adsorbent to synergistically solvate or decompose the composition on the screen to make it suitable for aqueous removal. . It should be noted that the decomposition agent for NMP #1 solvent must be essentially non-aqueous, because in the case of the present invention, a large amount of water negates the effectiveness of NMP in cleaning power. This is because it does. However, solvation ensures that the decomposed ink is then removable with a low volume pressurized water stream.

In addition to the surfactants listed above, other nonionic, ionic, cationic, and zwitterionic surfactants can be used. Mainly published in. Surfactants aid in dispersion and decomposition in the dye for aqueous removal. Ho Ion Oboro's surfactant is (1) Saponification of fat il
! 9 is a group of soaps, or (2) saponified petroleum salts such as sodium salts, or (3) saponified esters, alcohols or glycols, and the latter is an ionic synthetic surfactant. It is well known as a drug.

Examples of such ionic surfactants include arolyl sulfonates or their amine salts, such as dodecylbenzene sulfonate), and jetanolamine salts of teccylbenzene sulfonic acid. Most of these sulfonates contain multiple species. The name given to most of these is "alkylaryl sulfonate"
It is.

Simply put, it means that a paraffinic hydrocarbon is bonded to an aromatic nucleus or penzene and the aromatic portion is sulfonated. Saponification □ Examples of fatty acids (Cs-C24) are stearic acid, stearic acid, and sodium chlorine.
is a potassium salt, and nine is a mixture thereof. Some of this type of ultra-ionic surfactants include oxyalcohol-based higher alkyl phenols (JliiiD*). There are phosphoric acid esters. "Aeroaol OTJ is a dioctyl alkali metal sulfosuccinate anionic external surfactant manufactured by Ciana Kendo Co., Ltd.Suitable nonionic surfactants for use include hydrophilic moieties, usually polyoxyalkylene The oil-soluble and oil-loving portions of this molecule are derived from either fatty acids, alcohols, and the appropriate selection of starting materials and polyoxyalkylenes. By adjusting the chain length, the surface-active moieties of non-ionic detergents can be varied in a known manner. Examples of non-ionic surface-active agents include phenoxypolyol in alcohol, diethylene glycol, e.g. , ethylene oxide adducts of either nonyl- or tridecyl-phenol, and the like.

These nonionic surfactants are usually prepared by the reaction of phenol in alcohol with ethylene oxide. Trademark [TritonX-1] from Rohm & No.
00maku is x-114J, and is a trademark from Maehanion Carpai P and Carbon Co., Ltd. [T@rgitol
There are alkylphenyl ethers of polyethylene glycol commercially available under J. Other specific examples of nonionic surfactants include glyceryl monooleate, oleyl monoisopropanolamide solgitol dioleate, alkanolaines such as monoisoglopanolaine, jetanolamine, or motumenolaine and fatty acids. For example, oleic acid, Peral! It includes alkylolamides produced by reacting phosphoric acid, 2-carboxylic acid, etc., and their derivatives. Cationic surfactants are also well known and mention may primarily be made of betaines and g-tetraammonium compounds. Specific examples of pemains include the imidazoline pemains, aliphatic and carboxycyclic betaines, and betaines having heteroatoms in the hydrophobic chain, such as dodecyl and cyprovir dimetelaone.

Typical examples of quaternary ammonium compounds that can be mentioned are dimethyl dicocoammonium chloride, cetylpyridinium acetate, methylcetyl biperidinium derogionate, N,N-zotouchyl-N,N-zomethylammonium diethophosphate. To, etc., like this,
It will be appreciated that any anionic, cationic, zwitterionic or nonionic surfactant of the ring can be used in accordance with the principal component of the present invention.

The amounts of the components can vary widely, but N-methyl-2-
Preferably, a sufficient amount of pyrrolidone is used, i.e. about 60-85% by weight, and the fading solvent typically contains Ti in an amount of about 15-65% by weight. The remaining amount of the composition is approximately 1% by weight ~
The surfactant or mixture of surfactants ranges from about 5% by weight. If particularly fast penetration is required for ink l-11, NMPIm! The thick liquid may be supplemented with other organic solvents such as methylene chloride, trichloroethane, dimethyl sulfoxide and its derivatives, fluorocarbons, and freons in an amount of about 10 to 30% by weight; It does not change the essential percent properties of the product and serves to increase the penetration, emulsification and ink decomposition promoting effect of the rounding aid for subsequent removal.

To further illustrate the invention, specific working formulations and methods for cleaning and regenerating printing screens are provided below.

Example 1 75.72% N-methyl-2-pyrrolidone 18.52
% Butyl cello, 04% Cyclohesenone 1 2.62% Oct,, Rufuenoxy (/Rieto Nakako Etitle (TRITON X-114) 0.10%
Ac 411 cynic acid ester (o*n゛Ac RP-710) Example 2 57.86% N-methyl-2-pyrrolidone 926%
Butyl Cellosolde 1.52% Cyclohexanone 24.00% Celonorde Acetate 26.00% Methylene Chloride 1.61% Octylphenoxy VCdl Lithoxy) Fi/-L (TRITON, X-114) 0.05%
Organic Synthetic Ester (GAFACRP-710,) 50% Example 1 may be combined with 26% methylene chloride and 24% 4% cellosolve acetate in Example 2 specific ingredient number 9. Examples 1 and 2 are It is a preferred formulation for NMP cleaning fluids due to its degradability, reduced flammability and low TLV values.

Before detailing the cleaning and rejuvenating of printing screens using the method of the present invention, it is important to understand certain basic facts and uses. First of all, the ink side of the printing screen is also called squeegee side, fell side, or front tee P, but ink side is used here. The opposite side of the screen is the back side, and the down side is also called the cylinder contact side, but here we use the printed contact side. , synthetic enamel, continuous enamel, soft JIL lacquer, industrial lacquer, flat vinyl ink, vinyl-free tone ink, fluorescent ink, satin vinyl ink, adhesive, transparent ink, metal powder, acrylic ink,! Included are Tsustisol ink, Mylar ink, fiber ink, and ordinary ink or ink of the strip type. General literature on ink compositions includes KC Goods Fix Co., Ltd., 1978-197.
The 1978 Catalog, copyright 1978 by KC Graphics Co., Ltd., is a good reference. Also, Albert Kosloff
[Screen Printing for Textiles (T@xtil 0-911380-39-6 (1976)) is a good reference. These documents provide technical background regarding the ink that can be cleaned by the cleaning composition of the present invention. It is also useful for informational purposes. As previously discussed, printing screens can be made from a number of materials and have varying mesh sizes. Monofilament screens can be made from, for example, polyester, nylon, stainless steel, silk, or chrome plated. It is made of a single strand of material, such as wire, and is woven with a specific number of meshes per square inch (230 mesh means 230 holes per square inch). Multifilament screens are made from a set of strands of similar materials as described above, which are tied together before being woven into a shemesh. i.e. 12xx1
50 mesh means 12 strands P interwoven and then wrapped in 150 orifices per square inch; in this case, at the intersections of the meshes, if any pigment may enter the strands, it must be thoroughly removed. become, 1
Therefore, from the description of Ren's monofilament ``1□゛□□ment Fi multifilament, it can be seen that, for example, the requirements for complete removal of ink differ depending on the structure of the screen. "
The most common residue, referred to as "haze", is often found in multifilament screens, where the pigment gets trapped in the strands and becomes difficult to remove. There are a large number of l1IIIIl in the industrial resin that initially coats the printed contact side of the screen. For example, direta emulsion is a substance that can be removed with water, but is a substance that cannot be removed when exposed to specific waves and light.
sometimes hardens. For example, artwork can be placed on top of an uncured coating, in which case the alesion is reactive to water, and when exposed to a halide light, the artwork is covered in a circular pattern. Emal 2 that wasn't done
Part 17 is a water-reactive material. After a fixed exposure time of 9 Fi, remove the artwork - 1. Then, wash the screen with water to remove the light dust and remove the unwanted parts. The Cao-Kong-Zeng region is obtained. □The difficulty of layer removal is related to the number of coats on the mesh, such as drying and reapplying. Therefore, the difficulties in removing the emulsion depend on the number of coatings, whether it is strongly sensitized, the opening during exposure, the type of photoactivation, the chemical IL film agent used after the emulsion development, and its relaxation factor. Depends on a number of factors involved.

Viewed from the above background, the cleaning composition of Example 1 has approximately 20%
Non-aqueous concentrated PL with a flash point of 0”1F (95°C)
waves, and it is designed to remove a wide variety of inks and paints from screens.

Another feature of this method is that the NMPlj thick solution of Example 1 is treated or sensitized for removal of a large number of supernatants by a subsequent low volume high pressure water wash.

It is fast-acting, highly efficient, economical because it can be used in small quantities, biodegradable, and does not require red label (DOT flammable) labeling. Also, leaving the screen on the screen for a long time before washing with water is =r*. In the method of the present invention, the ink on the screen is sprayed thinly by a coagulating spray to prevent volatilization, and then held for about 2 to 5 minutes in a pressurized machine at about 60 to 10 Opsi (typically 40 psi). is operated to provide a condensed flow of a thick filter through nine nozzles approximately 6 to 12' apart from the screen. After spraying, the decomposed ink is treated with high pressure lIJ et al. $150 ~ IU 00
Easily removed by low volume water washing with pal. Low capacity means a minute car of 92 to 4 gallons. Fan spray has been found to be preferred for its balance of power and volume.

A suitable fan spray nozzle is the UniJet 65 from Spraying Systems (Eaton, Illinois).
/ 01. As explained above, it is important that the screen on which the liquid is solubilized or degraded is kept away from the water during washing. The presence of water either in the NMP concentrate or on the screen reduces the effectiveness of the composition.

The most preferred cleaning technique to create the advantages of the present invention is to spray the cleaning thickened casing thinly and evenly onto the screen inktide and then for a short period of time, depending on factors including cleaning system, ink composition, treatment time, etc. This is a method of holding the meeting for a few minutes to several hours. During this holding time, the cleaning loss penetrates the ink, emulsifies it and
become The ink stays on the screen, but the previous ink
F% property is destroyed. During the holding time, N-methyl-2
-Pylorigen and #! In addition to the co-solvent action of the bulking agent, the surfactant penetrates the ink composition during dispersion rounding and aids in subsequent removal of the ink by water. The interaction of all three components allows the ink to solubilize, dissolve, and form a crystalline dispersion suitable for removal. N-Methyl-2-pyrrolidone provides water activity to the rounding composition that is fq capable of removal by water, but the water must be under pressure such that it blows the ink composition away from the screen. . The components of the composition are finely balanced so that the organic components of the ink are solubilized or decomposed by both the N-methyl-2-pyrrolidone and the oxygenated solvent. Furthermore, although the activity of soluble Rolidone in the ink is degraded by water, it decomposes in the presence of IMP and co-solvents. It is possible to remove it from In this regard, it is preferred to use a slicing fan to sweep the screen from bottom to top using a stream of water so that the ink is removed without redeposition.

The composition of Example 2 above is used in a cleaning method similar to that of Example 10 Solvent-Based Thickening. However, the presence of methylene chloride improves penetration throughout the composition and also improves the dissolution properties of the 74soldeacetate #'i composition. Other organic solvents that can be substituted for methylene chloride υ include 1,1.1-')V other chlorinated solvents such as chlorotetraethane, dimethylsulfoxyvJ:... its derivatives and fluorocarbons. can be mentioned. In either case, the addition of a rounding organic bath agent that improves penetration □ evaporates easily and the retention time on the screen becomes very short. For example:
Example 1! Although the material is left on the screen surface for several hours, the composition of Example 2 is typically applied for a few minutes, eg, 2 to 5 minutes. Furthermore, it should be understood that the ink solubilizer of Example 1 may be subsequently used in combination with the cleaning chain case of Example 2. For example, during a cleaning operation, The ink is solubilized by the chain float of Example 1, in which case the screen needs to be left for no more than a few hours after processing and before removal by flushing. In such cases, fresh decomposition float of Example 2 may be applied after this holding time to activate the residue for removal by a subsequent low volume high pressure water wash. Also, the amount of material sprayed onto the substrate is variable, but typically within the range of several ounces per square foot, e.g. 2 to 4 ounces per 6 feet square of screen.
It is an ounce.

Therefore, preferably, the method of the present invention includes spraying the surfactant liquid of either Example 1 or 2 onto the screen. It is an economical, low volume method that allows for hold time to solubilize and/or degrade the Spray Co. ink. The substrate is then exposed to a low volume high pressure water stream.

It is broken down into 9 ink compositions and helps remove them by rounding 7 ounces! It is preferable to use rays.

If the solubilized and degraded screen is simply immersed in water, the ink will stick and the screen will not be effectively cleaned, f! Those skilled in the art will understand from the description of this application that there are thresholds for the power and amount of water used.

It has been observed that in connection with the method of cleaning screens with small area concealing sprays, the light mist tends to adhere to other remaining areas of the decomposed ink, and this problem is repeatedly solved by the addition of another component. By doing so, nine of the reductions are eliminated. This component is characterized as a hydrophobic liquid, and it has been found that the water-soluble synthetic oil sold at UCON is satisfactory. Depending on the amount of quarter mist or splatter that is pre-washed with water, the surfactant units may contain a component of the NMP III thick liquid floating liquid dispersant, which water-dispersible oil is Ozu Kashii Water Spray Ti acts as a water repellent for ist, but NMP
#! The removal of a low volume pressurized water stream of a predissolved and solubilized ink composition into a thick liquid suspension is problematic. Such water I
The Type I oil is polyalkylene glycol O@, which is often used as a UCON lubricant manufactured by Union Carby P., but other types and mixtures of varying water solubility may be used. A preferred V&^ molecular weight is UCON50-HB5100.

As a specific compound, gellicol or thioxirane polymer in polyalcohol, CAB Registry 4905
Mention may be made of B-95-5 ethoxylated lanolin or ethoxylated castor oil. However, it is preferred that the nine types of oils described herein do not remain on the screen after thorough water washing.

If the printing screen has to be completely removed after cleaning, the process is as follows: When the printing job is completed, the operator should clean the screen. Squeeze out the ink remaining on the ink side and the ink on the printed contact side. First, from a practical point of view, ink is expensive during printing, so we must try to recover as much ink as possible.From a cleaning point of view, excess ink can be removed to reduce haze. Requires larger amounts of cleaning composition to regenerate screens free of yeast residue. After the screen has been thoroughly carded and removed from the printing press, the cleaning process begins. If the process is a direct regeneration, generally speaking one float of either Example 119F: or 2 can be used depending on the type of ink. Spray either concentrate onto the ink side of the screen and then transfer to the regeneration station.

In the direct regeneration process, direct regeneration begins within about 5 to 10 minutes after application of the composition of either Example 1t or 2. After spraying any concentrate, rinse the printed contact side of the screen with high pressure water as previously described, thereby removing all or substantially all ink. at the same time,
The entire surface of the emulsion is wetted with water and becomes suitable for application of the polyphylate-containing emulsion remover. It can be seen that there is a synergistic effect caused by the use of the non-aqueous concentrates of Examples 1 or 2, since a residue of the concentrate remains even after the water-washing spray, thereby making the emulsion a quick-removal round sensitizer. It is said that it will be done. It is believed that in this direct regeneration process, the emulsion is somehow softened or made permeable for treatment with periodate-containing emulsion removers4. A suitable example of an emulzone remover is shown in Example 6.

Example 6 94, Li 26% Water 2.880% Sodium metaperiodate 6.000%
Syn-Sodium (Anhydrous) 11ON Omer Ionic Surfactant/1000 lbs. Water Screen 31 remover containing lactic acid salt! Spray it onto the image from the print head and leave it there for about 15 seconds to several minutes. That is generally sufficient time for the solution to disintegrate. Wash the emulsion off the screen again using high pressure spray. As explained earlier, it is important that the residual effect of Example 1 or 20-membered thick liquid after water washing is exploited immediately by applying a periodic acid-containing emulsion remover for a long period of time. It has been found that the removal of the emulsion decreases by 1 after 30 minutes, for example. Therefore, the residual effect of the cleaning composition of the present invention is synergistic as long as complete removal of the emulsion is achieved through interaction with such a persulfate-containing emulsion carbon removal agent.

Finally, if residual yeast images such as those described above occur, particularly where ghost images occur in conjunction with multifilament screens, an image remover may be used. However, it must be noted that the occasional presence of afterimages does not necessarily impede the reuse of the screen. Some screen printing machines are not precise! ! 4) Even if there is a part where you can see the screen, the lines of the screen itself are not obstructed.

If a dust or haze remover is used, a typical remover is a caustic solution of an oxygenated solvent. The reason for using such is that they can be washed with water, i.e. they are aquarium-compatible, and they do not leave behind residues that later cause emulsion problems. When using this type of yeast or haze remover, due to its increased viscosity, it must be applied with a syrup, roll or card rather than a spray. A typical composition is as follows: 61.64% Cyclohexanone 19.40% Cellosolve Acetate 38.85% Sodium Hydroxide! (50%)9.61%
DOWFAX 2A1 @Liquid (didodecylphenoxybenzenedisulfone cough sodium 70%, r-decylphenoxybenzenedisulfone sodium concentrate 60%) 0.01% Brilliant Millinglet P Dai 0.51
% GAFACRP-710 (as shown above).

K to completely regenerate screens that require time-consuming treatment.
It is sometimes important to be able to process the screen after about several hours of ink decomposition.
Then again apply a condensate spray of the type shown above without mist to reduce evaporation, thus wetting the screen and keeping the ink wet for a period of time.
It becomes easier to keep 〇 in a trench. However, it takes a long time to take the emulsion to a screen shop for complete removal, and it tends to dry out, causing some of the emulsion to run down the print side of the screen. In such cases, contacting the recycled material with a water spray after treatment with the composition of Example 1 to separate the ink will cause the Example 1 to form on the print side of the screen. Respray the composition of No. 2 to freshen up the residue. The chain float of Example 2 was resprayed onto the printed contact side of the screen, at which point the emulsion was sensitized to suit subsequent reaction with a lulsion remover as described above. 19,
If t-stink or haze occurs, a t-stst remover may be used as indicated above.

An important aspect of this cleaning and regeneration method is that it eliminates the need for screen degreasing, which was required when typical products useful in the prior art were used on the screen for ink and lusion removal. Deru, conventional,
Toluene, acetone, molten salt, trisodium phosphate, and other solvents or cleaning agents of the type set forth in the Background of the Invention have been used to remove oily residue from the screen at the end of the dais. SUMMARY OF THE INVENTION The present invention provides a highly effective system for completely removing ink and margin from printing screens, which has not been achieved heretofore.

From the above detailed description, a printing screen cleaning and reclamation method has been provided which has clear advantages over conventional methods. Additionally, methods have been provided for using the unique compositions of the present invention in synergistic action with other compositions in the process of cleaning and regenerating screens. Based on the above detailed description, it will be easy for those skilled in the art to create variations from the working force method in the embodiments within the scope of the present invention.

Substitute person Asamura Hajime 4 other people

Claims (1)

[Scope of Claims] (1) A liquid composition comprising N-methyl-2-pyrrolidone, an oxygenating storage agent, and a surfactant sufficient to entrap ink residue on a printing screen and decompose the ink residue. A method of cleaning a printing screen having ink residues on its surface, comprising the steps of: retaining the ink residue on the surface of the ink for a period of time; and washing away the dissolved ink residue with a pressurized water stream. 2) The method according to claim jlII, wherein the washing water is applied as a fan spray. (3) The water washing is pressurized low-volume water washing, Claim 1
Section method. 4. The method of claim 1, wherein the oxygenated solvent is selected from the group consisting of decylcelonolde, cellosolve acetate, and Schiff-shuntonone, and mixtures thereof. (5) The method according to claim II (4), wherein the ink surface retention time is about several minutes to several hours. (6) After several hours of hold time and before washing with water, the degraded ink was washed with a chain spray consisting of N-methyl-21'E-lydone, oxygenated solvent, methylene chloride, and surfactant. The method according to claim 1. (7) The method according to claim 11jllI, which is carried out under room temperature conditions. (8) The method of claim 1, wherein said surfactant is selected from the class consisting of nonionic, ionic and amphoteric surfactants, and mixtures thereof. (9) The liquid composition essentially consists of N-methyl-2-pia
11. The method of claim 11j111, comprising a non-aqueous dispersion comprising about 60-85% IJ tons, 10-35% oxygenated liquid and 1-5% extra-active liquid. Ql. The method of claim 1, wherein the liquid composition additionally contains a water-dispersible oil. (2) The water-dispersible oil is selected from the group consisting of polyalkylene glycols, ethoxylated lanolin, and ethoxylated mustard oil, especially! F. The method of claim 10. (A liquid composition consisting of 13N-methyl-2-pyrrolidone, an oxygenating bath agent, and an external activator is sprayed onto the ink residue on the printing screen, and the composition is held on the ink surface for a sufficient time to decompose the ink residue.) The decomposed ink residue is then washed with a pressurized water stream, the washed screen is briefly contacted with a periodate-containing emulsion remover, and the resulting screen is exposed to a pressurized water stream to form an engineered Marzo 17 image. A method for cleaning and regenerating a printing screen having emulsion print images and ink residues on its surface, comprising the step of removing. The periodate-containing emulsion remover is an aqueous solution of IJium. The method of claim g12, wherein the method is a liquid. 17. The method of claim 16, wherein the periodate-containing emulsion remover additionally contains an ionic surfactant. 4. The method according to claim 12, characterized in that after the final water flush, gastric alkali S*, which is an Il plating solvent, is applied to the screen to remove yeast. (L Xun) The gastric alkaline solution of the oxygenated bath agent consists of a solution of an oxygenated bath agent and a surfactant selected from the group consisting of sodium hydroxide, cyclohexanone, cellosolve acetate, and a mixture thereof. The method of claim 15.I The method of claim 12, wherein said surfactant is an ionic surfactant.11 After said holding time and before the first water wash, the resulting nine-screen residue is N-methyl-2-pyrrolidone,
an oxygenating agent, a surfactant, and a group consisting of methylene chloride, dimethina sulfoxide, and chloroform (
#. The method according to claim 1i12, which comprises spraying a composition comprising a selected surfactant. H. The method of claim 18, which is carried out under room temperature conditions. 4. The method of claim 12, wherein the liquid composition additionally contains a water-dispersible oil. cIυ Upper water dispersible oil is polyalkylene glycol,
The method of claim 20fA, wherein the method is selected from the group consisting of ethoxylated lanolin and ethoxylated castor oil.