US3067056A

US3067056A - Improvements in printing with ink composition having volatile solvents

Info

Publication number: US3067056A
Application number: US846750A
Authority: US
Inventors: Robert K Remer
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-10-15
Filing date: 1959-10-15
Publication date: 1962-12-04
Anticipated expiration: 1979-12-04

Description

Dec. 4, 1962 IMPROVEMENTS IN PRINTING WITH INK COMPOSITIONS Filed 001;. 15, 1959 R K. REMER HAVING VOLATILE SOLVENTS 2 Sheets-Sheet l INVENTOR.

fiaber/Z Earner,

Dec. 4, 1962 R. K. REMER 3,067,056

IMPROVEMENTS IN PRINTING WITH INK COMPOSITIONS HAVING VOLATILE SOLVENTS 2 Sheets-Sheet 2 Filed Oct. 15, 1959 46 P0706164 I/UAOE C )1 01/02}? INVEN TOR. Edie/Z75 56/7266 BY ll Ill/ll l J AI'IJ'AIIAIVJMIMIJIJIJIA' I United, States Patent 3,967,056 IMPRDVEMENTS IN PRINTHNG WITH lNK COM- PQSITIGN HAVHNG VGLATELE SOLVENTS Robert K. Renter, 1814 Noyes St, Evanston, Ill. Filed Get. 15, 1959, Ser. No. 846,750 18 Claims. (Qt. 11736) My invention relates, generally, to improvements and innovations in methods and apparatus for printing web or sheet materials such as plastic films, paper, foils, non woven fabrics, netting and textile fabrics.

According to my invention an ink is dispersed or dissolved in a chlorinated solvent which is retained in the lower portion of a tank or in a fountain. Means may be provided in the bottom of the tank or fountain for heating and controlling the temperature of the ink. The etched or mechanically knurled printing cylinder of a rotogravure printing unit is mounted in the tank or fountain so as to run in the ink bath at the proper depth. The 'web or sheet material being treated is passed through the intaglio or rotogravure printing unit located in the lower part of the fountain and thereby receives a metered surface deposit of the ink or coating in the form of tiny dots characteristic of intaglio or rotogravure printing. The ink may be applied as an over-all coating or in the form of a design and/or words and numerals. The volatile chlorinated solvent is immediately vaporized after deposit, leaving behind a metered deposit of the ink composition on the surface of the web. The upper portion of the tank or fountain extends above the printing unit so as to retain the vapors therein and is provided with condensing means for condensing the solvent vapors so as to recover the same and prevent them from leaving the foun tain. The web or sheet leaves the top of the tank in a substantially dry, solvent-free condition.

It has been found that this particular printing or coating process is practical when the ink is applied from a rotogravure or intaglio type cylinder. Because of the type of deposit laid down on the web from such a cylinder in the form of multitudinous fine dots, it is possible to flash off and recover practically all of the chlorinated solvent used as the vehicle. When the web being printed is a fibrous or absorptive material such as paper, the chlorinated solvent still vaporizes from the tiny dots before it becomes absorbed or picked up by the web. The deposit which is applied by an etched or rotogravure cylinder is very uniform and by selecting the depth and screen size of the etching or knurling, the amount of the deposit or coating can be very closely controlled and accurately metered. The web being printed or coated travels at a fast speed which makes the process practical and economical without requiring large and expensive drying equipment and tunnels such as commonly are used in connection with rotogravure printing employing expensive volatile solvents.

An object of my invention is a method of and apparatus for continuously printing or coating a travelling web or sheet by depositing thereon a suitable ink or coating composition dispersed or dissolved in a chlorinated solvent vehicle contained in a tank or fountain, the deposit being applied by a rotogravure cylinder in such manner that the solvent quickly evaporates therefrom and is condensed in the upper portion of the tank while the web leaves the tank in a substantially solvent-free condition.

Another object of my invention is a method of and apparatus for continuously printing or coating a travelling web or sheet by passing same over a rotogravure printing cylinder running in a bath of ink or coating composition dispersed or dissolved in a chlorinated solvent vehicle and then passing the web or sheet upwardly through an upper portion of the tank or fountain wherein the solvent Tree vapors evolved from the bath and from the deposit applied to the web or sheet are condensed and recovered while the web or sheet leaves the tank or fountain in a substantially solvent-free condition.

Another object of the invention is a method of and apparatus for printing or coating polyethylene, polyvinyl and polyester films by passing such films over a rotogravure or intaglio printing cylinder running in a bath of ink or coating composition dissolved or dispersed in chlorinated solvent vehicle in the bottom portion of a fountain, and condensing in the upper portion of the tank or fountain the solvent vapors which are evolved from the bath and from the printed or coated film whereby the film leaves the fountain in a substantially solvent-free condition.

Another object of the invention is a method of and apparatus for making carbon paper without strike through by printing and depositing a coating which will not rub 01f, by passing a continuously running web or sheet of paper over a rotogravure printing cylinder or coating roll running in a bath of carbon ink dispersed in a chlorinated solvent in the bottom of a fountain and passing the web or sheet of paper out through the top of the fountain which is provided with a condenser for condensing solvent vapors evolved from the bath and from the printed or coated paper which leaves the fountain in a. substantially solvent-free condition.

Another object of the invention is an apparatus for printing a continuously travelling web or sheet comprising a relatively deep fountain having a rotogravure printing unit disposed in the bottom portion thereof so that the printing cylinder runs in a bath of an ink or coating composition dissolved or dispersed in a volatile solvent, with heater means in the upper portion of the fountain above the level of the bath for driving solvent off from the printed or coated web, and associated condenser means for condensing solvent vapors so that they do not escape from the fountain and may be returned to the bath or separately recovered.

Another object of the invention is a rapid method of printing on polyethylene film in one or more colors with an ink that adheres firmly to the polyethylene without any prior or separate heat-conditioning or chemical treatment of the film to make it take the ink, which method in nowise impairs the normal heat-sealing properties of the polyethylene.

Another object of the invention is polyethylene film which has been printed or decorated in one or more colors without being subjected to any heat conditioning or chemical conditioning treatment and on the surface of which the inks adhere firmly both to the surface of the film itself and one ink on top of another ink when the film is printed color-on-color.

Another object of the invention is an inexpensive method of and apparatus for rapidly producing one-time carbon paper, without wicking which is the cause of strike through, by continuously passing a web of paper over a rotogravure printing cylinder disposed in the bot tom portion of a fountain containing a bath of one-time carbon ink dissolved or dispersed in chlorinated solvent, rapidly releasing solvent vapors from the deposit applied to the paper and condensing the evolved solvent in the upper portion of the fountain above the level of the bath so as to recover the same While the one-time carbon paper produced leaves the fountain in a substantially solvent-free condition.

Another object of the invention is a one-time carbon paper characterized by its excellent reproducing properties and a high resistance to rub-01f or smudging.

Another object of the invention is a new and improved ink composition for printing on films having non-ab- 8,0 3 sorbent waxy-like surfaces such as polyethylene, polyvinyl and polyester films.

Another object of the invention is a new and improved carbon ink composition adapted to be dissolved or dispersed in a hot solvent for use in printing one-time carbon paper.

Certain other objects of the invention will in part be obvious and will in part appear hereinafter.

For a more complete understanding of the nature and scope of the invention, reference may now be had to the following detailed description thereof, wherein certain illustrative examples and embodiments are set forth.

In the accompanying drawings:

FIG. 1 is a diagrammatic view showing one type of apparatus and illustrating one method whereby my invention may be practiced;

FIG. 2 is a top plan view of a fountain which forms the bottom part of an apparatus constituting another embodiment of the invention and which has been successfully used to practice the same;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2 and showing in addition the bottom end of a condenser unit that fits on top of the fountain;

FIG. 4 is a vertical sectional view through the condenser unit which fits on top of the fountain of FIGS. 2 and 3;

FIG. 5 is in FIG. 4;

FIG. 6 is a detail sectional view on enlarged scale taken on line 6-6 of FIG. 2;

FIG. 7 is a fragmentary detail sectional veiw on enlarged scale on line 77 of FIG. 4; and

FIG. 8 is an enlarged detail section taken online 8--8' or FIG. 4.

In FIG. 1 a fountain or tank is indicated at 5' which may be formed of suitable material such as stainless steel and in which is disposed adjacent the bottom thereof a rotogravure or intaglio printing unit comprising a printing cylinder 6, an impression cylinder or roll 7, and a doctor blade 8. Any suitable intaglio or rotogravure printing unit of known type may be usedfor the purpose of this invention. The printing cylinder 6 may have an over-all printing surface or it may carry a design wherein there are printing areas and non-printing areas. The cylinder 6 may be an etched cylinder or a mechanically knurled cylinder. If a knurled cylinder or an over-all etched cylinder is used and it is desired to have nonprinting areas, such areas may be obtained by treating them with a film-forming material such as Teflon (tetrafluoroethylene polymer).

One or both of the

cylinder

6 and 7 may be electrically heated in a well known manner by one of several commercially available electrical heater units in order to hasten the evaporation of the solvent and the setting of the coating or printed matter on the web or sheet. An electric heater element 9 of known type is shown wound on the support shaft for roll 9.

The lower portion of the printing cylinder 6 runs in a liquid bath contained in the bottom of the fountain or vessel 5 comprising an ink or coating composition dissolved or uniformly dispersed in a-chlorinated solvent. A number of formulations for such a bath will be de-' scribed in detail hereinafter in the examples. When a relatively heavy over-all deposit or coating is to be deposited on a web (e.g. as by a cylinder having a 35 to 65 line screen) the bath in the bottom of the fountain 5 should usually be maintained at or about its boiling temperature so that the solvent vapors will be rapidly evolved from the surface thereof and from the deposit of the bath which is applied to the travelling film or web 10 as it passes through the printing or coating unit. On the other hand, when only light over-all printing or small design areas are printed on the Web 10 (e.g. as a cylinder having 165 to 200 line screen), then it usually will not be necessary to heat the ink bath above room temperature.

a top plan view of the condensing unit shown When heating is desired, the temperature of the bath may be controlled in any one of a number of ways such as by passing a heating fluid (gas or liquid) through a coil 11 located in the bottom of the fountain. Any fluid heating medium of suitable heat transfer and other physical characteristics may be used, such as steam, oil or Dowtnerm (eutectic mixture of phenyl ether and 26.5% of diphenyl oxide having a boiling point of 258 C.). A condenser coil 12 is fitted around the upper portion of the fountain 5 so as to cool or chill the upper portion of the fountain above the printing unit so as to condense the solvent vapors evolved from the bath and from the deposit of the bath applied to the web 10 and cause the condensate to run down the side walls of the fountain on the inside. It will be understood that any suitable and known type of condenser may be used, either external or internal, and any suitable heat transfer fluid can be passed through the condenser 12 at the proper temperature and rate of flow. However, for purposes of economy cool or cold water will ordinarily be used as the condensing medium.

A supply roll of the web or sheet material to be printed is indicated at 13 and the wind-up roll of the printed or coated sheet or web material is indicated at 14. As is well understood in the art, the wind-up roll 14 will ordinarily be driven, as well as the rolls of the printing or coating unit in the fountain 5. The web or sheet 10 is guided into the fountain 5 by passage over a freely rotating guide roll 15 and passes out from the fountain over a freely rotating guide roll 16.

An ink composition suitable for dissolving or dispersing in a chlorinated solvent to make a bath to be used in the fountain 5 for printing polyethylene film is set forth in the following example:

The foregoing ink formulation may be prepared in a ball mill or in a colloid mill in accordance with known ink-making techniques. Approximately 35 parts of the ink formulation are dissolved in 65 parts of chlorinated solvent, preferably trichloroethylene. Other chlorinated solvents which may be used include perchloroethylene, pentachloroethylene, ethylene dichloride, trichloromethane, dichloromethane and methylene chloride. Commercial grade chlorinated solvents may be used alone or in suitable mixtures.

When a relatively heavy over-all coating or deposit is to be applied to the web 10 by the printing cylinder 6, steam or other heating medium is passed through the heater unit 11 so as to raise the temperature of the bath to about the boiling point (e.g. F. in the case of trichloroethylene) so that the lower portion of the fountain 5 surrounding the printing unit is filled with hot solvent vapors. If only printing or small-area designs are being printed, it is not necessary to heat the bath. As the printing cylinder 6 revolves in the solvent bath a film of the liquid adheres to the surface thereof which the doctor 8 removes from any non-printing areas and the excess from the printing areas in the usual manner, and thereafter the composition is transferred from the small depressions constituting the printing areas onto the undersurface of the film 10 as it passes through the bite or kiss contact between the printing cylinder 6 and the impression roll 7. The chlorinated solvent almost immediately escapes or is driven off from the film, leaving the ink set and adhered to the film. Sufficient condensing water is passed through the condenser 12 so as to chill or cool the upper portion of the fountain 5 to the point where the solvent vapors are condensed on the inside and do not escape from the fountain. When the printed film It) leaves the fountain 5 It is in a substantially solvent-free and dry condition and may be rewound immediately. If the ink composition is highly plasticized the final setting of the ink or coating may be hastened by means of a suitable drier indicated at 17 which may take the form of infra-red lamps, heated air blowers, or heated idler rolls.

When the apparatus is operated properly with the ink bath being heated when required, practically no solvent leaves the fountain 5, and therefore while the bath becomes gradually depleted of the ink or coating composition dissolved in the solvent as it is deposited on and carried away on the travelling web or sheet very little solvent is lost. A supply or extender tank 13 is mounted on the side of the fountain 5 for containing a supplementary supply of the ink or coating composition, which preferably is dissolved in some of the chlorinated solvent so as to make up a concentrated solution. The supply tank 18 is provided with an outlet conduit 20, the bottom end of which passes through the side wall of the fountain 5 adjacent the bottom thereof, as shown. The flow of the concentrate is regulated by means of a valve indicated at 21.

if it is desired to print the film 10 in more than one color, the film It may be passed through additional printing units of the same type as shown in FIG. 1 so that the film is printed either in registration or in a color-on-color relationship, as is well understood in the art.

7 The ink formulation of Example 1 may be varied in several respects.

While the chlorinated rubber and butadiene-acrylonitril copolymer is a preferred resin combination, either of these may be used alone and other synthetic rubber polymers and copolymers and resins soluble in chlorinated solvents may be employed, e.g. styrene'isobutylene copolymer. Likewise, methyl abietate and diallyl phthalate is a preferred plasticizer combination, but other compatible plasticizers may be used. Other antioxidants may also be used as well as other pigments. Also dyes which are soluble in chlorinated solvents may be used in place of pigments, if desired.

Other films besides polyethylene that may be printed by the process described in connection with FIG. 1 include cellulose acetate, regenerated cellulose, chlorinated rubber (Pliofilm), vinylidene chloride copolymer (Saran), polyvinyl acetate and polyester films.

Another ink formulation which is particularly adapted for printing on polyethylene is the following:

Example 2 Parts by weight Nylon scrap (thread) 7-0 Cresylic acid 30 Hausa Yellow (yellow pigment) 10 The nylon is dissolved in the cresylic acid and thenthe pigment is milled in. Approximately 110 parts of the mixture are added to 90 parts of chlorinated solvent (trichloroethylene) so as to make up a bath suitable for use in the bottom of the fountain 5.

Still another ink-chlorinated solvent formulation for printing on polyethylene film according to the present invention is the following:

Example 3 Parts by weight Chlorosulfonated polymer of ethylene (Hypalon Phenolic maleic acid ester resin (Super- Beckacite 1001, Reichhold) 20 Chlorinated diphenyl (Arochlor) 20 The following is a suitable formulation for an adhesivecomposition for manufacturing pressure sensitive adhesive tape:

, polyethylene or Saran.

Example 4 Parts by weight Methyl abietate 15 Alpha-methylstyrene polymer (Dow Resin 276V2) 15 Hydrogenated rosin (Staybelite Ester 10, Hercules) 15 Chlorinated rubber (67% chlorine) 15 2,2-methylenebis (4-methyl-6-tertiary butylphenol), heat and light stabilizer Sixty-two parts of this formulation are dissolved in 38 parts of trichloroethylene to prepare a bath suitable for use in the apparatus shown in FIG. 1 for applying a pressure sensitive adhesive coating to one side of a travelling Web of plastic film such as cellophane, cellulose acetate, The same formulation may also he applied to advantage to a web of plastic, non-woven fabric, glass fabrics, textile fabrics or paper.

A suitable carbon ink formulation for making one-time carbon paper in the apparatus shown in FIG. 1 is shown in the following example:

Example 5 Parts by weight Armid O- 30 Steararnide 6% Oleamide 91% Linoleamide 3% Sugar cane wax 3O Chlorinated paraflin 5 Carbon black l Alizarin blue 1 2,2-methylenebis (4 methyl-6-tertiary butylphenol) 1 This formulation can be ball milled or milled in a colloid mill and 68 parts of the ink can be dissolved in 32 parts of trichloroethylene to make up a bath for use in the apparatus of FIG. 1.

The following formulation is specially adapted for application to a web or sheet for depositing thereon an electrically conductive coating: 7

Example 6 Parts by weight Acetylene carbon black 25 Chlorinated parafiin 20 Methyl abietate 20 Lithium nitrate (or lithium chloride) 1t) Seventy-five parts of this ink composition may be dissolved in 25 parts of chlorinated solvent to prepare a fountain bath which may be appliedin the apparatus shown in FIG. 1 in accordance with the method of operation described above to provide printed circuits, printed dry cells and various electrical circuitry, The following is an example of a magnetic coating composition which may be applied to paper or other sheet material according to the process of this invention:

Example 7 Parts by weight Carbonyl iron powder (or any iron oxide powder) 25 Chlorinated paraffin 25 Methyl abietate 25 Seventy-five parts of this formulation may be dissolved in 25 parts of chlorinated solvent and used as the fountain bath in the apparatus of FIG. 1. After application to a sheet or web the resulting coating may be magnetized.

The apparatus and method of the present invention may also be used advantageously for the continuous printing of metal foils such as aluminum foil. Such a foil may be passed through the apparatus shown in FIG. 1 and printed on the underside with an ink having the following formulation:

Example 8 Parts by weight Ethyl cellulose (low viscosity) 2O Alpha-methylstyrene polymer (Dow Resin 276V2) 10 Parts by weight Methyl abietate 10 Azo Oil Blue B Forty-five parts of this formulation are dissolved in 55 parts of trichloroethylene or other chlorinated solvent and used as the fountain solution in the apparatus of HG. 1.

The following ink composition in chlorinated solvent is particularly adapted for printing on films of cellulose acetate and Mylar polyester films using the apparatus of FIG. 1:

Example 9 Parts by weight Ethylene dichloride 45 Methylmethacrylate (Plexiglas) 45 Glacial acetic acid 10 TiO pigment 10 The apparatus shown in FIGS. 27 has been used to advantage in practicing the invention and it represents a preferred working embodiment of the invention. The apparatus comprises a fountain indicated generally at 25, on top of which is mounted a condenser indicated generally at 26. If desired, additional condenser units up to any desired weight, may be added to provide additional condensing capacity and a longer time for theprinted web to be heated if desired before it leaves the apparatus.

The fountain and condenser 26 may be fabricated from sheet metal of a type which will withstand chlorinated solvent and solvent vapors. The fountain 25 has a bottom 27 and side walls 23'. A rectangular frame 39 sets into the upper ends of the vertical side walls 28 and supports the bed or bottom of the fountain indicated at 31. The frame 30 on two sides has a U-shaped cross section so as to form channels 32 as indicated in FIG. 3 having laterally projecting flanges 33 integrally formed thereon. The opposite sides of the frame 30 also have U-shaped troughs 34- (FIG. 6), laterally projecting flanges 35 and a horizontal inner flange 36 which supports a vertical flange 37.

The U-shaped troughs or

channels

32 and 34 communicate with each other around the periphery of the frame 30 for the purpose of providing a drain into which condensed solvent is collected and from which it may be drawn off through an outlet connection 38 (FIGS. 2 and 3). Referring to FIG. 6, it will be seen that the condensate first drips onto the inner horizontal flanges 36 and then runs off these flanges into the communicating

troughs

34 and 32. The gasket 60 serves to space the bottom of the condenser 26 off the flanges 36 so as to allow this draining action.

The bottom of the bed 31 is generally horizontal while the opposite ends are upwardly curved as shown in FIG. 3. Ink or coating compositions may be introduced into the fountain through an outside riser 40 having a cover 41 hinged to the top thereof and adapted to be closed by means of a wing nut 42. The bottom end of the riser 40 communicates with a horizontal connection 43 which opens into the bed of the fountain through an opening 44.

The top edges of the vertical flanges 37 slope downwardly from opposite ends toward the middle into semicircular recesses 45 as shown in FIG. 3. The recesses 45 serve to provide clearance for the shafts or journals on the opposite ends of a rotogravure or etched cylinder 46.

It will be seen that the fountain 25 has a hollow construction under the floor 31 and this is for the purpose of holding a hot liquid such as oil, water or Dowtherm when it is necessary or desirable to heat the contents within the fountain as when printing an overall coating on the web W. The heating liquid may be introduced into the fountain through the connection 47 and withdrawn through the discharge connection 48. It will be understood that instead of using a liquid, or a gas such as steam, for heating the fountain that other heating means can be used such as an electrical resistance heater or a radiant heater. If flexibility of the unit is' not important the false bottom 31 may be omitted along with the

connections

47 and 48. Even though the unit has no provision for heating the ink bath, it may still be heated exteriorly and circulated by suitable pump means.

The condenser unit 26 is generally rectangular in shape and has a hollow-walled construction. The exterior walls of the condenser unit are indicated at Three of the inner walls are the same and are indicated at 51. The fourth inner wall is different in that it is corrugated as indicated at 52 so as to provide additional condensing or cooling surface since it is adjacent this wall that the printed web or film passes upwardly on its way out of the condenser unit. The speed at which the various webs may be printed or coated may be increased by using a heater of known type which is indicated diagrammatically at 53. This heater is juxtaposed to the corrugated wall 52 and is somewhat curved or rounded on that side and has a smooth surface over which the non-printed or non-coated side of the web W may ride and receive heat. Thus, the function of the heater 5?; is to present a hot surface for heating the printed web W. Advantageously, the front surface of the heater 53 over which the web passes may be perforated with numerous pores or openings 59 as shown in FIG. 8 through which air may be blown. Air may be introduced into the heater 53 through the pipe 69 under suflicient pressure to discharge it through the openings 59. The air may be heated when introduced and will be heated as it passes through the heater 53. The air assists in removing residual solvent from the printed web and in setting the deposited ink. Depending on the volume and pressure, the air or other gas discharging through the openings 59 serves as an air cushion between the travelling web and heater surface.

Coolant such as cold water or brine is circulated through the condenser unit 26, being introduced at the top adjacent one corner through the inlet 5'4 and being Withdrawn from the bottom adjacent the opposite corner through the outlet 55. hollow walls are closed off as indicated at 56 and 57 in FIG. 4. The bottom of the condenser unit is provided with a peripheral flange 58 which is dimensioned to meet or fit opposite the laterally extending

flanges

33 and 35 on the frame 3% of the fountain as shown in FIG. 3 with a gasket 60 fitting therebetween.

The rotogravure roll or cylinder 46 and its impression roll 61 are located in the lower portion of the condenser 26 with the bottom of the cylinder 46 running in the fountain bath. The journals or supporting shafts on the opposite ends of the

cylinders

46 and 61 project through the side walls of the condenser unit 26 through aligned sets of openings provided therein as shown in FIG. 7. On the interior of the opposite side walls of the condenser unit an integral bearing plate formed of a material such as Teflon is located as designated at 62. Each of the Teflon plates 62 has an integral upper sleeve bearing 63 and an integral lower sleeve bearing 64. These bearings project through the circular openings provided therefor in the opposite side walls of the condenser unit. The journals 65 on opposite ends of the rotogravure cylinder 46 carry on their outer ends a pinion gear 66 which meshes with a pinion gear 67 mounted on the outer end of the journal 68 supporting the impression roll 61. The rotogravure cylinder 46 and impression roll 61 are driven in a known manner. A doctor blade 7a is provided for removing excess ink or coating composition from the rotogravure cylinder 46.

The web W of material to be printed is introduced into the apparatus over a guide roll 71 and is guided out of the unit over a guide roll 72. The web W passes between the rotogravure cylinder 46 and the impression The top and bottom ends of theroll 61 so as to receive on its underside the ink or coating composition deposited thereon from the rotogravure cylinder 46.

Preferably the printing cylinder 46 is arranged to be heated such as by the insertion therein of an electrical resistance heating element 7? of known type such as a calrod heater element of suitable shape. The heater element may be used to heat the printing cylinder 46 to a temperature of 180 F., for example. The purpose in having the cylinder heated is to expel or volatilize the solvent faster from the dots which are deposited upon the web W and to cause the dots to flow and merge one with another into a continuous film. Also, heating renders the ink in the wells highly fluid and facilitates their emptying. The heater 53 in the upper portion of the condenser unit 26 may also be heated to a similar temperature, i.e. around 180 F., for example. By heating the printing cylinder 46 and using the heater 53 it is possible to operate the printing or coating machine at higher speeds, especially when air is blown through the perforated surface of the heater 53.

It is sometimes desirable that the web W be heated when printed and this may be conveniently accomplished by use of a radiant heater 86 disposed just ahead of the guide roller 71. One or more such heaters may be provided on the same, or on opposite sides of the web.

The Width of the webs which are printed or coated may be varied depending upon the dimensions of the machines which are used. These machines may be used to print or coat several spaced webs of kraft paper having widths of about 1 inch, and after such webs have passed through the printing unit they may be twisted into paper cord or twine of the type that is used in manufacturing rugs, binder twine, show stitching cords and the like. Sets of twisting rolls for twisting paper into such cords are known and in use. Such sets of rolls of known type may be located within the fountains or tanks of the apparatus shown in FIG. 1 or in FIGS. 2-7.

Chlorinated solvents are used in this process for a number of reasons. They vaporize readily at low temperatures since they are low boilers, e.g. between about 104 to 160 F. Since the vapors are much heavier than air they settle rapidly into the bottom of the condenser units. These vapors condense easily and if desired for use in other formulations may be readily reclaimed by distilling and condensing. Chlorinated solvents are in the nature of dry solvents which do not wet or hydrate the webs even if the web happens to be a highly porous and absorptive material such as newsprint. When these chlorinated solvents are heated they have very high dissolving or suspending capacities for materials used in the ink or coating compositions including resins, fillers and pigments. Such materials dissolve or disperse readily in chlorinated solvents to a much higher or greater extent than they can be dissolved or dispersed in ordinary solvents. This high solubility and dispersibility is due to the combined solvent power and the heat. In practice, resins, fillers and pigments and other materials which are used in the inks or coating composition to be applied in accordance with the present invention are milled in the heated phase into or in the presence of hot chlorinated solvent and then the compositions may be allowed to solidify. When they are to be used, the solidified compositions may be heated and then thinned or extended as desired with additional hot chlorinated solvent. By following this procedure, it is possible to easily provide inks or coating compositions which contain up to as much as 50 to 60% solids. In the usual cold ink or coating compositions the solvent phase usually does not exceed 20% by weight.

Chlorinated solvents are non-polar and by the incorporation therein of various known anti-static chemicals or agents they will serve to change or convert the polarity of a web such as newsprint from a negative charge to a positive charge while being printed or coated in accordance with this invention. This conversion or change in electrical charge is facilitated by having the impression roll formed of Thiokol, Teflon, or silicone rubber materials which are loaded with graphite or molybdenum disulphide. By employing anti-static chemicals or agents in the chlorinated solvents and by also forming the impression roll of one of the anti-friction materials mentioned above, it is possible to eliminate or substantially prevent the wicking action normally associated with a pressure printing operation such as is involved in a rotogravure or rotogravure printing unit.

In View of the teaching contained in the foregoing examples, those skilled in the art will be able to make and use either the compositions specifically disclosed herein or probably such modified formulations as may be required for their needs without departing from the spirit and scope of the present invention.

This application is a continuation-in-part of my copending application Serial No. 624,385, filed November 26, 1956, and now abandoned, which in turn was a continuation-in-part of my prior application Serial No. 367,- 206, filed July 10, 1953, and now abandoned.

What is claimed as new is:

l. The method of rotogravure printing a web which comprises, conducting the web in a continuous manner in printing contact with a non'immersed portion of a rotogravure cylinder only the bottom portion of which rotates in a bath of ink dispersed in chlorinated solvent maintained at a temperature at which said solvent is rapidly volatilizing, said rotogravure cylinder being disposed in the bottom of an enclosed fountain provided with superposed condensing means and having an impression cylinder associated therewith for holding said web in said printing contact, passing the printed web upwardly through said condensing means so as to leave said fountain in a substantially solventfree condition, and condensing said solvent at a rate sufficient to prevent escape of solvent vapor out of the top of said enclosed fountain.

2. The method of claim 1 wherein the condensed solvent is collected and removed so as not to return directly into said bath.

3. The method of claim 1 wherein the condensed solvent is returned to said bath and additional ink or coating material is added to said bath so as to make up for the amounts carried away on said web.

4. The method of claim 1 wherein said web is paper.

5. The method of claim 1 wherein said web is a film selected from the group consisting of polyethylene, polyvinyl and polyester films.

6. The method of claim 1 wherein said solvent is trichloroethylene.

7. The method of rotogravure printing a web which comprises, conducting the web in a continuous manner in printing contact with a non-immersed portion of a rotogravure cylinder only the bottom portion of which rotates in a bath of ink dispersed in chlorinated solvent maintained at a temperature at which said solvent is rapidly volatilizing, said rotogravure cylinder being disposed in the bottom of an enclosed fountain provided with superposed condensing means and having an impression cylinder associated therewith for holding said web in said printing contact, passing the non-printed side of said web over a heated surface while the printed side passes in close proximity to a condensing surface without contacting the same, and condensing said solvent at a rate sufilcient to prevent escape of solvent vapor out of the top of said fountain.

8. The method of rotogravure printing polyethylene film which comprises passing polyethylene through a printing unit having the bottom portion only of the rotogravure cylinder running in an ink bath containing chlorinated solvent and heated at least approximately to boiling.

9. The method of making carbon paper comprising passing a web of paper through a printing or coating anemone i unit running in a fountain bath containing carbon ink dispersed in a chlorinated solvent and heated at least to approximately boiling.

10. The method of printing polyethylene film comprising passing polyethylene film through a rotogravure printing unit disposed in the bottom of a fountain and running in a bath in the bottom of said fountain wherein the vehicle is chlorinated solvent and the bath is heated at least approximately to boiling, and condensing in an upper portion of said fountain solvent vapors evolved from said bath and the printed film.

11. The method of claim wherein said ink oath comprises rubber base resin, coloring material and chlorinated solvent.

12. The method of claim 10 wherein said bath comprises chlorinated rubber, butadiene-acrylonitrile copolymer, methyl abietate, diallyl phthalate, and coloring material dispersed in chlorinated solvent.

13. Rotogravure printing apparatus comprising a deep fountain, a printing unit comprising a ro-togravure cylinder and an impression roli disposed in the bottom of said fountain, and condenser means in the top of said fountain for condensing solvent vapors therein.

14. The apparatus of claim 13 wherein the rotogravure cylinder is heated.

15. Rotogravure printing apparatus comprising a deep enclosed fountain, a rotogravure printing unit disposed in the bottom of said fountain, heater means for heating a bath of ink or coating composition in the bottom of said fountain, condenser mean in the upper portion of said fountain having at least one extended surface, stationary heater means having a heatable smooth extended surface juxtaposed to said extended condensing surface, and guide means for conducting a web after passing through said printing unit up and out of said fountain with its non-printed side passing over said heated surface.

16. In a rotogravure printing unit having a deep fountain and a rotogravure printing unit disposed in the bottom thereof, condenser means in the upper portion of said fountain providing an extended condensing surface, heater means providing an extended heater surface juxtaposed to said condensing surface, and guide means for conducting a web after passing through said printing t2 unit up and out of said fountainwith its non-printed side passing over said heater surface.

17. In a rotogravure printing unit having a deep fountain and a rotogravure printing unit disposed in the bottom thereof, condenser means in the upper portion of said fountain providing an extended condensing surface, heater means providing an extended heater surface juxtaposed to said condensing surface, guide means for conducting a web after passing through said printing unit up and out of said fountain with its non-printed side passing over said heater surface and second heater means disposed to pre-heat the Web prior to printing.

18. In a rotogravure printing unit having a deep fountain and a rotogravure printing unit disposed in the bottom thereof, condenser means in the upper portion of said fountain providing an extended condensing surface, heater means providing an extended heater surface juxtaposed to said condensing surface, and guide means for conducting a web after passing through said printing unit up and out of said fountain with its non-printed side passing over said heater surface, said condenser surface being so oriented as not to overhang the path of said printed Web.

References Cited in the tile of this patent UNITED STATESv PATENTS 739,313 How Sept. 22, 1903 1,236,002 Nivling Aug. 7, 1917 1,544,675 Moller July 7', 1925' 1,740,979 Golrick Dec. 24, 1929 1,961,827 Rutkoskie June 5, 1934 2,223,924 Stephan Dec. 3, 1940 2,290,200 Murch et a1. July 21, 1942 2,304,818 Grupe Dec. 15, 1942 2,396,946 Grupe Mar. 19, 1946 2,515,489 Borushko July 18, 1950 2,519,321 Newman Aug. 15, 1950 2,618,574 Pavlic Nov. 18, 1952 2,659,340 Zinn Nov. 17, 1953 2,675,779 Borushko Apr. 20, 1954 2,685,572 Perkins Aug. 3, 1954 2,837,493 Schlenker June 3, 1958 2,936,286 Feick May 10, 1960

Claims

1. A COMPOSITION COMPRISING ACID-MODIFIED POLYESTER

8. THE METHOD OF ROTOGRAVURE PRINTING POLYETHYLENE FIBER DYED WITH A DYE OF THE FORMULA FILM WHICH COMPRISES PASSING POLYETHYLENE THROUGH A