US3870651A - Carbonated organic solvent - Google Patents

Abstract

The carbonated solvent is an aromatic hydrocarbon solvent containing gaseous carbon dioxide interstitially spaced in the solvent in an amount in excess of one and up to about four volumes of gaseous carbon dioxide per volume of solvent.

Description

o ,1 Umte States Patent 1191 Pipkins Mar. 11, 1975 [54] CARBONATED ORGANIC SOLVENT 1 2,221,093 11/1944 Hillman et a1. 208/316 2,281,865 5 1942 V D" k 208 319 [751 Imam" Dav"! DOWN Grove, 2,315,131 3/1943 P11 @1 21 208/323 2,321,023 6/1943 Goodhue et a1. 424/45 2,631,966 3/1953 Francis 252/364 173] Asslgnee' l F 3,694,546 9/1972 Roth et al. 424/45 1 Mmneapolls, Mmn. I 22 Filed: Apr. 1 1973 OTHER PUBLlCATlONS 21 A L N 352,215 l-lerzka, A., Medicaments in Pressurised Dispersers, 1 pp 0 1 The Pharmaceuucal Journal, Feb. 2, 1963, pp. 87-91.

Related US. Application Data {60] Division of Ser. No. 154,411,.lune 18, 1971, Pat. No. primary Examiner Benjamin Padgett 3,747,523, which is a continuation-in-part of Ser. No. Assistant Examiner lrwin Gluck 1970 Attorney, Agent, or Firm-Morsbach & Pillote 106/311, 117/63, 206/7 [57] ABSTRACT 2 ;gi g P Q The carbonated solvent is an aromatic hydrocarbon I 8 f;,? "65:' 2O8/3l6 solvent containing gaseous carbon dioxide interstitially l spaced in the solvent in an amount in excess of one and up to about four volumes of gaseous carbon diox- 156] References Cited ide per volume of solvent.

UNITED STATES PATENTS 2,188,051 11/1940 Lantz 208/316 2 Clam, 4 Drawmg Flgmes PATENTEU MRI 1 i975 SHEET 2 BF 3 fIJEAHEUl'ARI 1 1123 saw 3 pg 5 CARBONATED ORGANIC SOLVENT CROSS-REFERENCE This application is a division of application Ser. No. 154,411, filed June 18, 1971, now U.S. Pat. No. 3,747,523; which in turn was a continuation-in-part of application Ser. No. 80,833, filed Oct. 15, I970, now U.S. Pat. No. 3,705,044.

BACKGROUND The invention pertains to carbonated paints, inks, and solvents, and to a method of printing using carbonated ink.

Paint is a mixture of a liquid and one or more powders called pigment. The liquid that carries the pigment is called a vehicle which may include solvents or thinners, binders, driers, and plasticizers. Typical solvents are turpentine, petroleum distillates, aromatic hydrocarbons, etc. Most solvents are classified as organic solvents. The term paint, as used herein, is intended to include ink, colorants and the like which are manufactured from pigments and vehicles or solvents.

During the manufacture or use of paint, ink, and the like, a fire hazard exists because of the use of flammable materials. For example, one area of fire hazard is at the mill where the pigment is ground and a temperature increase results. Another area is where the material (e.g., ink) is being applied as by a press. A static spark can ignite the volatile solvent and cause an explosion. It is advantageous to suppress flammability and reduce the fire hazard.

Paint is subject to oxidation during storage either in the plant, in the unopened can, or in the can after opening. Additionally, solvents can be lost into the head space above the paint. Consumers are familiar with skinning of paint caused by oxidation. It is desirable, therefore, to have a product which represses oxidation and/or loss of solvents during storage.

SUMMARY The present invention relates to new products in the form of carbonated paints, inks and solvents. The invention also relates to a method of printing using carbonated ink.

It is a general object of the present invention to overcome the above-described deficiencies of the prior art as it relates to paint and ink of the type which includes a pigment and an organic solvent.

Another object is to provide a product with reduced fire hazard.

It is another object to provide a product in accordance with the foregoing object which provides its own self-inerting atmosphere.

Still another object of the invention is to provide a product which overcomes the problem of skinning during storage,

Another object is to provide a method of printing which has any of the following advantages: increased print out, a decrease in static charges, or a reduction of flashing potential.

These, and other objects and advantages of the present invention, will become apparent as the same becomes better understood from the following detailed description when taken in conjunction with the accompanying drawings.

DRAWINGS FIG. 1 is a diagrammatic view of an apparatus suitable for producing the product of the present invention;

FIG. 2 is a reproduction of a micro-photograph of a gravure printing utilizing carbonated ink;

FIG. 3 is a reproduction of a micro-photograph of a gravure printing utilizing the same plate as in FIG. 2 but with regular ink; and

FIG. 4 is a diagrammatic view of an apparatus suitable for carbonating solvent.

DESCRIPTION One of the major operations in the manufacture of paint and ink is properly dispersing the pigment particles in the liquid vehicle or solvent. Various apparatus are provided for this purpose including ball mills, sand mills, roller mills and the like. The basic purpose of these mills is to intimately mix and wet the solid pigment particles with the liquid vehicle or solvent. This is a much more difficult process than would be readily appreciated and the usual milling or grinding time in a ball mill by present methods, ranges from about 6 hours for a formula that is easy to grind (e.g., a titanium dioxide formula white paint) up to 24 hours for a formula that is difficult to grind (e.g., a carbon black formula black paint). An average formula can take up to 12-16 hours of grinding time.

It has been found that the time required to disperse the pigment can be markedly reduced, for example to about one-third the time previously required or less, if a pressurized carbon dioxide atmosphere is utilized during milling. In other words, it has been found that carbon dioxide is substantial quantities in the mixture of paint pigment and solvent will markedly aid dispersion of the pigment. This appears to result at least in part, from an increased energy level and Brownian motion caused by the presence of carbon dioxide. In accordancewith the present invention, the carbon dioxide can be introduced directly into the mill either before or during milling. The pressure of carbon dioxide added is preferably in the range of 7 to I00 p.s.i.g.

It has been found that it is possible to achieve these improved results by introducing the carbon dioxide atmosphere into the liquid organic solvent prior to entry into the mill; for example, while it is in a storage tank. By proper regulation, the organic solvent will contain the desired amount of carbon dioxide when introduced into the mill. The carbon dioxide can be absorbed by the organic solvent by first pressurizing the storage tank and them pumping the organic solvent into the tank at a pressure above the pressure of the carbon dioxide atmosphere. Since the organic solvent will absorb the carbon dioxide, the solvent can be pumped into the tank without venting the same, as is presently required. It is estimated that as much as 4% of solvents are lost through venting and, with some solvents, this adds to pollution of the atmosphere. By carbonating the solvent, vaporization of the solvent is suppressed. Also under some conditions, the pressurized tank permits the delivery of the solvent to the mill without necessitating a pump as is presently required.

If sufficient carbon dioxide is interstitially spaced in the organic solvent through absorption, no carbon dioxide need be added at the mill. Preferably the storage tank pressure is at least 50 p.s.i.g. to achieve optimum results in this event. However, it is contemplated that carbon dioxide can be supplied to both the storage tank and the mill, if desired.

After the pigment has been dispersed or ground in the liquid solvent by the mill, it is delivered to a tinting tank where a tinter adds additional solvent and pigments, as described above. Surprisingly, it has been found that, in addition to a reduced grinding or milling time, the pigments and organic solvents ground in the presence of carbon dioxide have a greater tinctorial strength." This is also indicative of improved dispersion of the pigment. The result is that the product from the mill can have greater amounts of solvents or diluents added and yet obtain the required coverage ofthe paint or ink.

After tinting, the paint or ink can then be stored or put into a container for shipping. if a carbonated solvent is used during the tinting operation, the resulting paint or ink contains a high amount of carbon dioxide; preferably in excess of one volume and up to four volumes of carbon dioxide per volume of the organic solvent in the paint or ink. Some of this carbon dioxide can then evolve into the head space ofthe container to maintain an inert atmosphere in the container. In a paint can, this evolving continues through several openings by a consumer, and reduces loss of solvent and also inhibits skinning" of the paint. in an industrial use of ink. this evolving provides an inert atmo sphere above the ink and reduces the fire hazard. It has also been found that a carbonated ink has an increased conductivity which helps prevent the build up of dangerous static charges.

Reference is now made more particularly to the drawings which diagrammatically illustrate the best presently known apparatus of the present invention and which apparatus is one means of performing the method of the present invention.

The mill is in the form ofa ball mill which is essentially a large drum 12 mounted for rotation about a horizontal axis 14. As is usual, the mill contains pigment, vehicle or solvent. and balls, pebbles or the like which are tumbled as the mill rotates to intimately disperse the pigments in the solvent. The drum 12 has a removable cover 18 covering an opening 16 through which the pigments can be placed into the mill. The solvent is supplied through a conduit 22 arranged to dump through opening 16. Carbon dioxide is introduced into the mill through a branch conduit 26a which is connected to a carbon dioxide supply tank 30 by means of a main conduit 26. The carbon dioxide is preferably fed to the mill at a pressure in the range of 7 to lOO p.s.i.g. Branch conduit 26a is advantageously coaxial with axis 14- so that carbon dioxide can be supplied while the drum 12 is rotating. A valve 32 is conveniently provided at the outlet of tank 30. A valve 34 and a pressure regulator 36 are advantageously interposed in conduit 26a to control the flow of carbon dioxide to the mill. The drum 12 has an outlet to which a flexible conduit 24- can be connected to draw off the ground pigment and organic solvent.

A storage tank M) for the organic solvent preferably is unvented. A second branch conduit 26b is connected to the tank 40 and to main conduit 26 to feed carbon dioxide to the tank. A valve 44 and a pressure regulator 46 are interposed in conduit 26]; to control the flow of carbon dioxide to the storage tank. After the tank d0 has been supplied with carbon dioxide under pressure.

for example at 50 p.s.i.g., the organic solvent is pumped into the tank through a line 47 by a pump 48. A valve 49 is provided in line 47. The pump is arranged to supply the organic solvent into the tank 40 at a pressure above the pressure of the carbon dioxide. The solvency of the carbon dioxide increases with pressure increase and, as the carbon dioxide is absorbed by the solvent, the amount of free carbon dioxide is reduced. The carbon dioxide is absorbed and becomes interstitially spaced in the solvent and there is effectively no pres sure increase as the solvent is supplied into the tank.

At the bottom of storage tank 40 is an outlet conduit 52 which leads to the conduit 22 and to a tinting tank 60. A valve 54 in conduit 22 controls flow of the carbonated organic solvent to the mill 10; while a valve 56 in conduit 52 controls flow to the tinting tank 60. It will be noted that no pump is provided for moving the carbonated organic solvent to the mill or tinting tank. However, a pump could be provided if desired or if required, as when the solvent must be lifted a height beyond what the pressure of carbon dioxide will lift. A conduit 57 is connected to conduit 52 and flexible conduit 24 to effectively connect the mill 10 to the tinting tank 60. A valve 58 and a pump 59 are interposed in conduit 57 to control the flow from the mill 10.

As is usual, tinting tank 60 is provided with a mixer or agitator 62 driven by a motor 64 to mix the milled pigment and solvent with any additional solvents, pigments or additives. The tank is provided with an opening 66 through which the additional pigments and additives may be added. Opening 66 is provided with a cover 68 which may or may not seal the tank 60. The tank is provided with a poppet-type vent 72 so that the tank is vented. If cover 68 does not seal the tank. it should be arranged that a slight pressure (e.g., 3-6 p.s.i.g.) can be maintained in the head space. The head space is filled with carbon dioxide evolved from the paint or ink. This reduces fire hazard and inhibits vaporization of the solvent. While the evolved carbon dioxide is sufficient for these purposes most of the time, the tank is advantageously connected to the main con duit 26 by way of branch conduit 26(- in which is interposed a valve 74 and a pressure regulator 76. In this manner, the tank 60 can be maintained with an inert atmosphere even when no product is contained therein.

After the above-described operation, there is a carbonated paint or ink product. This may be dispensed into a tank or can through a conduit 82 connected to tinting tank 60. A pump 84 and a valve 86 are pro vided to control flow through the conduit 82. This dispensing can be accomplished either automatically or by a manual operation.

The carbonated product in can 80 preferably contains in excess of one volume of carbon dioxide per volume of organic solvent therein and up to about four volumes per volume. In this manner, the carbon dioxide will evolve into the head space of the container and provide an inert atmosphere. In the case of paint, it has been found that this evolved carbon dioxide inhibits vaporization of the solvent and reduces skinning tendencies. In the case of ink, it has been found that the carbon dioxide will evolve and provide a protective blanket even in an open container. This aids in flammability suppression.

It has been found that carbonation increases the flash point of the organic solvents. This also aids in reduced flammability. It has also been found that carbonation EXAMPLE I Parts by wt.

l. Benzidene Yellow 2. Primrose Chrome Yellow 1588 3. Toluol 361 4. Ethyl Cellulose Solution 2571 N.V.

in Lacquer Diluent Hydrocarbon Solvent 962 5. Zinc Resinate and Ethyl Cellulose Solution* 4962 6. Lacquer Diluent Hydrocarbon 1784 *This ingredient has the following composition by weight:

Zine Resmate 37% Ethyl Cellulose 3% Lacquer Diluent 5% Acetone 77 Isopropyl Alcohol l W: Hexane 257: Toluol 12% The above is a formula for yellow gravure ink. Ingredient No. 6 is added after milling for reduction. Ingredients 1-5 were milled in a ball mill of a laboratory size. The mill had 2,388 grams of steel balls therein. Four identical mills were utilized in the tests and each mill was turned the same number of revolutions for the same length of time. One mill held a control sample, and the other mills were charged with carbon dioxide to the pressure indicated, stabilized for 1 hour, and then repressured to the pressure indicated. Various tests were run for different lengths of milling time. The ground ingredients 1-5 were then reduced. Each sample was tested for fineness of grind by a North Standard grind gauge which is used to measure dispersion. The optical density measured on a Densichron densitometer manufactured by Welch Scientific Co., Skokie, Ill. The following results were obtained:

Test Grind time CO Fineness Increased Tint Strength l l hour None .3 Control do. l5 psig. 2V2 4% do. .150 do. 3 7 do. .15 do. 4 ll 2 2 hours None 5% Control do. l5 psig. 6 10% do. l t) do. 6 7 do. I do. 6V2 9 l 4 hours lNone 1' Control do. l psig. B 871 do. 150 do. I. 10 do. llUt) do. l 10 EXAMPLE 2 Ingredients as in Example 1 were added to a ball mill; except ingredients 3-6 were pressurized at 100 p.s.i.g. of carbon dioxide. Thus the solvent was precarbonated. A control sample was run simultaneously. The finished products were reduced and measurements taken as in Example I with the following results:

w i t l in Test Grind Time CO Fineness Increased Tint Strength 5 Z /hrs. None 3 /2 Control do. 100 psig. 4 692 6 6 hrs. None 4% Control do. 100 psig. 4 /2 1371 EXAMPLE 3 Ingredients as in Example 1 except that ingredient 6 was replaced by Xylol, 890 parts by the Xylol was added to the mill, and all the ingredients were exposed to carbon dioxide prior to milling but at varying pressures. The following results were obtained:

Test Grind Time CO Fineness Increased Tint Strength 7 4 hours None 4 Control do. 7 psig. 4 7% do. 15 do. 4% 21 do. 25 do. 4 15 do. 50 do. 4 9 do. do. 4% 9 do. do. 5 l4 EXAMPLE 4 Parts by wtv l. Benzidene Yellow 318 2. Primrose Chrome Yellow I702 3. VM & P Naphtha 1064 4. Ethyl Cellulose Solution 25% N.V.

in Lacquer Diluent Hydrocarbon Solvent 1064 5. Zinc Resinate and Ethyl Cellulose Solution 5320 6. Toluol 532 Ingredients 3-6 were precarbonated as in Example 2. The following results were obtained:

Test Grind Time CO Fineness Increased Tint Strength 8 4 hours None 6 Control do. 100 psig. 6 /2 12% EXAMPLE 5 Ingredients as in Example 1 were ground for four hours and then reduced. Various samples of this ink were then exposed to carbon dioxide at various pressures and agitated for 15 minutes. The following results were obtained:

Test Grind Time CO Fineness Increased Tint Strength 9 None Control 30 psig. 4% 50 do. 5 100 do. 10

The above examples show that inks have improved fineness when ground in the presence of carbon dioxide, either by precarbonation of solvents or by introduction into the mill. The examples also show that the addition of carbon dioxide to these products, by precarbonation, postcarbonation, or adding in the mill, improves the tinctorial strength of the end product. It can be seen that the tests include a broad range of organic solvents.

EFFECT OF CARBONATION ON FLASH POINTS I the average of three tests in each instance.

Material Carbonated Uncarbonated Mineral Spirits ll2.3 F. ll0.2 F. Xylol 91 79 Toluol 453 39 VMJtP Naptha 557 52.3

CONCLUSION The degree of rate of dispersion as evaluated by a 'fineness gage'improves with increased carbonation roughly proportionately in the rangeof 7-l00 -p.s.i.g.

Carbonation also results in increased tinctori-al strength at all pressures from 7400 p.s.i.g. but the increase is not proportional in all tests. With greater tinctorial strength and greater quality of dispersion,

greater brightness of color is observed in the products. The above pressures in precarbonation,postcarbonation, or added during milling, interstitially spaces over I one volume of carbon dioxide per volume of solvent.

The final product willhave from over one volume per volume up to four volumes per volume of carbon dioxide added. Alcohol solventsarecapable of absorbing somewhat greater quantities of carbon dioxide, however.

CA RBONATED ORGANIC SOLVENTS As explained above, carbonated products (e.g., inks) have advantages during use. Among the advantages of carbonated inks are (l) increased print out, (2) a decrease in static charges on the press, and (3) a reduc tion in flashing potential.

In the present usage, ink is ordinarily thinned by the addition of an equal amount of organic solvent prior to placing in the ink fountain of a press. by substituting carbonated organic solvent for regular solvent, the above advantages can be obtained. Preferably, the organic solvent has carbon dioxide interstitially spaced in an amount such that the final ink mix has over one volume per volume of carbon dioxide therein. Thus, if 50 percent of the final ink mix is organic solvent, as is usual, the carbonated organic solvent preferably has greater than two volumes of carbon dioxide per volume of organic solvent. Of course carbonated organic solvent having greater than one volume of carbon dioxide per volume of organic solvent is useful for mixing with carbonated ink having at least the same amount of carbonation. This will give the same advantages enumer ated.

As illustrations of carbonated organic solvents, sevcral organic solvents were pressurized at 100 p.s.i.g. of gaseous carbon dioxide until equilibrium was reached. Three tests were made on each carbonated organic solvent and the following results were obtained:

Organic Solvent Volumes of Carbon Dioxide Hexane 5 Heptane Mineral Spirits V M (it P Naphtha Toluol Xylol METHOD OF PRINTING Printing using carbonated inks includes the placing of the ink containing carbon dioxide into an ink fountain or receptacle, and supplying'the'earbonated ink to the printing mechanism which applies it with direct pressure to the material being printed.

Test 1: A. regular yellow ink having a regular solvent (Tolu-Sol" 30) were used for a selected printing on a gravure press. Thereafter, the regular ink was replaced with a carbonated yellow ink containing in excess of one volume of carbon dioxide per volume of the or-' ganic solvents therein. Copiesofeachwere checked for I printability, hue, strength and characteristics. During each run, readings of static charges were taken on the 2 cylinder with a WSM-2950 Static Meter fromWcstern LII Static Eliminator Company. Finally, the regular ink and the carbonated ink were placed in half-pint cans and ignited.The following results were observed:

-l. Nopress difficulty was encountered in the change over.

2. There was an increase in print out.

3. Static charges decreased from 31000-40000 volts using regular ink to l0,000-l 5,000 volts using carbonated ink.

4. The regular ink burned rapidly, while the carbonated ink glowed but extinguished itself immediately.

Test 2: The procedure of Test 1 was followed except that yellow, red, blue and black inks were tested. The following results were observed:

(1) and (4) Same as Test 1.

(2). There was an increase in print out. FIGS. 2 and 3 are photolithographs of micro-photographs of the results with the yellow carbonated ink and yellow regular ink, respectively. In the area of FIG. 3, there are about 27 voids (dots missing) indicated at 92. In FIG. 2, there are about seven dots missing as indicated at 92'. Additionally, the dots with carbonated ink are more regular and defined. There is less blurring between dots as seen, for example, at 94 in FIG. 3. The white specks in both FIGS. 2 and 3 are caused by the photographic process and should be ignored.

3. An average of three static charge readings gave the following results on two successive days:

DAY l:

Black (vlts.)

Blue

(vlts.)

Yellow (vlts.) 7.500

Carbonated Inks Regular Inks Test 3: The procedure of Test 2 was followed under controlled humidity (46 percent) and temperature (67). with the following results:

(1), (2) and (4) Same as Test 1.

(3). Static charges decreased from an average 25.000

volts on regular inks to about 10,000 volts on carbonated inks.

It has also been found that more reasonable results are obtained with carbonated inks in a proofing press which is used to check plates for proper etching.

The improved print out of FIG. 2 is surprising. While it is not known exactly why this occurs with carbonated ink, it is theorized that it may be the result of mechanical agitation or normal increased press temperature either of which would cause the carbon dioxide to evolve from the ink. in the gravure press, the ink is at relatively calm position in the fountain. When the roll of the gravure cylinder passes through the ink fountain the carbonated ink is picked up at moderate rest. Immediately afterwards a steel blade called the doctor blade scrapes offexcess ink. The doctor blade operates under considerable pressure .at a high rate of speed commensurate with the rate of roll ofthe cylinder. This does two things. It causes a severe agitation .or shear at the surface of ink under the doctor blade and possibly increases the temperature locally. These two factors cause carbon dioxide to evolve. [t is theorized that the ink then filled with bubbles of carbon dioxide puffs up to a point that it sits proud of the roll and is more easily picked up by the paper and more efficiently picked out of the cavities in the gravure roller. It is also possible that the carbon dioxide lowers the surface tension of the ink with the improved result described.

In placing the ink containing carbon dioxide into an ink fountain or receptacle, it is advantageous to mix on site a pigmented product with a volatile liquid organic solvent having gaseous carbon dioxide interstitially spaced therein. One advantageous arrangement is to provide apparatus for carbonating the solvent at the printing site.

FIG. 4 illustrates one suitable apparatus for carbonating the volatile liquid organic solvent. As shown, two solvent storage tanks 101 are each provided with an outlet valve 102 which controls flow to a supply line 103. The tanks .101 may. for example be 10,000 gallon tanks mounted in suitable saddles (not shown) and provided with an explosion proof pump (not shown) for tank car unloading of the solvent to the tanks 101. The storage tanks 101 are advantageously provided with flame arresters (not shown).

A storage unit 104 is provided to store liquid carbon dioxide without loss at 300 p.s.i.g. and F. The unit is conveniently of 6 ton capacity, formed of fiberglass reinforced with resin plastic and insulated with polyurethane. Refrigeration is provided by a three-fourths HP condensing unit 105. A vaporizer 106 converts the liquid carbon dioxide to gas preparatory to feeding a gas line 107.

A carbonating unit 114 'is connected to supply line 103 and to a branch 107a of gas line 107. The level of solvent in the unit 114 is controlled by a float 115 in a mannerhereafter described. The amount of gaseous carbon dioxide flowing to unit 114 is controlled by adjusting the pressure which is recorded on gauge 116. After sufficient agitation. the solvent will have the carbon dioxide interstitially spaced therein. The carbonated solvent can then be withdrawn through a valve 117 to a point of usage such as the fountain or a mixing room. v

lnterposed in supply line 103 is a positive displacement pump 125,11 recording meter 127, a check valve 124, and an electrically actuated. air-operated ball valve 128. The pump is driven by a motor 126 and is capable of delivering the solvent at a pressure up to 125 p.s.i.g. A bypass line 103a around the pump has a relief valve 123 therein.

The ball valve 128 is controlled by the float 115 in the carbonating unit 114. Whenever there is a reduction in the liquid level of the unit 114, the float 115 actuates a four-way solenoid valve 131 at the end of a branch 10717 of gas line 107. Valve 131 directs the gas through lines 1076 and 107d to control opening or closing of valve 128. Simultaneously with opening valve 131, controls start operation of the pump 125, and vice versa.

Preferably, some gaseous carbon dioxide is fed into supply line 103 before the solvent reaches the carbonating unit 114. For this purpose gas line 107 connects to line 103 after valve 128. It has been found desirable that this connection be at least 10 feet prior to entry of the materials into the carbonating unit. lnterposed in gas line 107 are two disassembly valves 133 between which are a check valve 134 and a piloted pressure regulator 135.

It is now deemed obvious that there has been disclosed improved products in the form of carbonated paints, inks and solvents as well as an improved method of printing. The carbonated ink, and the method of printing using it, results in increased print out and increased safety through reduction of fire hazards.

I claim:

1. A carbonated solvent for paints and inks comprising: an aromatic hydrocarbon solvent selected from the group consisting of toluol and xylol; and gaseous carbon dioxide interstitially spaced in the solvent in an amount in excess of one volume of gaseous carbon dioxide per volume of solvent and up to four volumes per volume.

2. A carbonated organic solvent as set forth in claim 1 wherein the gaseous carbon dioxide interstitially spaced in the liquid organic solvent is in an amount of greater than two volumes per volume of liquid organic solvent for mixing with an equal amount of pigmented product containing no carbon dioxide.

l= l l

Claims (2)

1. A CARBONATED SOLVENT FOR PAINTS AND INKS COMPRISING: AN AROMATIC HYDROCARBON SOLVENT SELECTED FROM THE GROUP CONSISTING OF TOLUOL AND XYLOL; AND GASEOUS CARBON DIOXIDE INTERSTITIALLY SPACED IN THE SOLVENT IN AN AMOUNT IN EXCESS OF ONE VOLUME OF GASEOUS CARBON DIOXIDE PER VOLUME OF SOLVENT AND UP TO FOUR VOLUMES PER VOLUME.

1. A carbonated solvent for paints and inks comprising: an aromatic hydrocarbon solvent selected from the group consisting of toluol and xylol; and gaseous carbon dioxide interstitially spaced in the solvent in an amount in excess of one volume of gaseous carbon dioxide per volume of solvent and up to four volumes per volume.

Images