US2121022A - Marked article and process for producing the same - Google Patents

Description

June 21, 1938. R. T. K. CORNWELL 2,121,022

MARKED ARTICLE AND PROCESS FOR PRODUCING THE SAME Filed Aug. 25, 1955 175417016007" 18 WasMA/e vw m I I I,

TTORNEYS 3 wave/mm;

Patented June 21, .1938

PATENT OFFICE ARTICLE AND PROCESS FOR PRO- DUCING THE SAME Ralph T. K. Cornwell, Fredericksburg, Va.,'as-

signer to- Sylvania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia Application 1mm 23, 1935, Serial no. arse-i 5 Claims.

The invention relates in general to the formation of indicia and in particular to a process for printing a pellicle of a hydrophilic colloid while in the gel condition, and includes correlated im- 5 provements designed to enhance the decorative character of the printed colloid.

' Heretofore indicia produced on articles formed of a hydrophilic colloid in the gel state by direct printing with an ink comprising an organic dyestui! have not been satisfactory. With the prior methods of direct printing, the dyestuif was foundto' be deposited chiefly on the surface, the deposit was not sumciently dense and the edges of the indicia were diffuse. It. has also been suggested to produce indicia on hydrophilic colloids while in a dry condition by direct printing with inks con-v taining opaque pigments, such as titanium oxide. In this process, the deposit is formed only on the surface of the material, so that the indicia showvery little adhesion to the base,.and frequently bleed and flake of! when the article is immersed in water. a

It is a general object of the invention to provide articles formed from non-fibrous material capable of forming a hydrogel with an indicium which is characterized by being opaque, relatively permanent, strongly adherent when immersed in water and diflicult to alter or remove, and a process for the production thereof.

A more specific object of the invention is to provide shrinkable container closures, formed of a hydrophilic colloid, with indicia comprising a dense deposit of an opaque color having a substantial depth of penetration and sharpness of outline, and a process for the production of such closures.

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

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect toeach of the others, and the article possessing the features and properties which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims. v

According to the invention, an indicium of sat-, isfactory density, depth and sharpness of outline may be produced on a non-fibrous material capable of forming a hydro-gel and especially a hydrophiiic colloid in the gel state by printing the colloid having a pigment formed in situ therein previously or simultaneously with the: printing operation. Preferably, the gel is-further condi tioned for printing by impregnating it with a water-miscible solvent for the dyestuil employed in the ink. The impregnated material is printed with an ink comprising a substantive or direct dyestuif carried in a water-miscible vehicle.

The-expressions gel state and gel condition are employed herein to designate the condition 5 of a pellicle, of a hydrophilic colloid which has been impregnated with a water miscible swelling agent therefor and which is also a solvent for substantive dyestuffs.

For a more complete understanding of the na- 10 ture and objects of the invention, reference should be had to the accompanying drawing, in which:

Fig. 1 is a diagrammatic representation of. an apparatus for carrying out certain steps of the process;

Fig. 2 is an illustration of a seamless tube formed from a hydrophilic colloid which has been printed in accordance with the invention;

Fig. 3 is a view of a printed shrinkable closure band; and

Fig. 4 is a view of a printed shrinkable closure cap.

The process may be applied for printing various hydrophillc colloids in the gel state such, for example, as cellulose hydrate, those ce1lulose 25 ethers which swell in water and dissolve in alkalies, gelatine, casein and the like. The cellulose hydrate may be derived from viscose solutions or solutions of cellulose in cuprammonia or in zinc chloride. The hydrophilic colloid may be in the form of sheets, films, hollow bodies such, for example, as capsules,'or seamless flexible tubing which is adapted to be used as sausage casings or which may be severed into short .lengths to form shrinkable closure bands. The process is also applicable for printing non-fibrous materials which are capable of imbibing water and forming a hydrogel.

Prior to the step of printing, the hydrophilic colloid in the gel state is conditioned by impregnating it throughout or in predetermined areas with a pigment consisting preferably of an opaque inorganic compound which is insoluble in water. The pigment is formed in situ, for example, by treating the gel successively with solutions of inqrganic substances which react to precipitate the inorganic compound within the gel. The inorganic reagents may be dissolved in any solvent having a swelling action on the hydrophilic colloid, suitable solvents being water and the lower 50 monoand poly-hydric alcohols, such as ethyl alcohol, ethylene glycol; also triethanolamine and the like, either singly or in admixture. The first used inorganic substance, reagent A, is preferably, applied as a relatively dilute solution, while the '55 second inorganic substance, reagent E, is applied as a relatively concentrated, preferably a satu rated, solution. The excess of the first solution is removed from the surface of the material be fore the application of the second solution, so that the reaction takes place only within the material. In order to hasten absorption of the reagents, the solutions may be used at a raised temperature such as 40 C.

The inorganic substances are chosen so as to precipitate in situ an inorganic compound which is of a color different from and preferably lighter than that of the dyestuff to be employed, so as to form a proper and contrasting background for the indicia. The color of the inorganic compound may be used to modify the color of the dyestuff to obtain various shades of color and different degrees of contrast.

By way of illustrating the invention, but not by way of limitation, the following examples may be given of appropriate inorganic reagents for use with an ink containing a black dyestuii'. other combinations of inorganic substances and other color contrasts for dyestuffs other than black The process of conditioning the gel for printing includes preferably the step of impregnating the hydrophilic colloid with a solvent of the dyestufif employed in the ink, as described and claimed in my co-pending application, Serial No. 37,526 filed August 23, 1935. A suitable dyestuff solvent is one which is miscible with water, preferably hygroscopic, capable of penetrating the hydrophilic colloid such, for example, as polyhydric alcohols such as glycerine, ethylene glycol, diethylene glycol and ethers thereof such as methyl, ethyl, butyl, etc.; and organic nitrogen compounds derivable from ammonia such, for

example, as the amines, amides, tetrammonium' compounds, especially the alkyl and hydroxyl derivatives of these compounds such as the ethanol-amines. Thus, the article to be printed may be first conditioned by immersing it in a bath containing 50% of water and 50% of monoethyl ether of ethylene glycol. The dyestuff solvent which is incorporated in thegel may be the same as or different from that used in the ink. Since the ink vehicle is water-miscible, the hydrogel may be impregnated with the entire ink vehicle, if desired, in lieu of impregnating only with the dyestufi solvent.

-Water adhering to the surface of the article after pigmentation and solvent impregnation, is removed before printing, preferably by drying the surface as by passing a blast of warm air thereover, but care should be taken that the gel is not dried throughout. Preferably, the gel is printed while it is at a temperature higher than atmospheric to increase the rate of penetration of the dyestufl.

The surface-dry and conditioned gel is printed water.

with an ink or composition containing a substantive, i. e. a direct dyestufi dissolved in a watermiscible solvent. These dyestufis are those used for the direct dyeing of cotton and other forms of cellulose. Suitable dyes are those known as benzoform colors, plutoform black, formyi colors, diamine aldehyde colors, of which the following may be given as examples: Benzo fast red L and GL, benzo fast yellow, benzo: pure blue, (Zolumbia blue, benzo fast blacks, diamine deep black, oxydiamine blacks.

The dye is selected so as to have a high solubility in the water-miscible solvent and a relatively low solubility in water, or be insoluble in Preferably, there is used a dyestuif of which the fastness to light and water can be improved by a suitable after-treatment such, for example, as a treatment with an aqueous formaldehyde solution. In some cases the stability of the dye to light and water may be increased further by treatment with copper sulphate or potassium dichromate. It is preferable to wash the dyestuil' thoroughly in order to remove inorganic salts which are commonly present therein. If such salts are permitted to remain in the dyestuii', they tend to crystallize within the material and detract from the strength and transparency of the hydrophilic colloid.

The dyestuff is carried in a water-miscible vehicle containing a water-miscible solvent for the As further illustrating the invention, the fol-' lowing examples of a suitable ink composition are presented:

Ink vehicles Percent Percent Percent Percent Percent Triethanolamine 60 Butyl other of diethylene glycol 50 50 Methyl ether of glycoL 60 10 Diethylene glycol 20 20 20 Water 40 20 30 30 20 One of the above vehicles is saturated with a. direct or substantive dyestufi such as benzoform blue BBL, benzoform orange and 'benzoform green FFL.

The process of the invention may be illustrated by reference to Fig. 1, in which an endless tube I of cellulose hydrate is passed from the supply .roll 2 through a vat 3 which may contain 2 parts of sodium dichromate in 98 parts of water maintained at a temperature of about 40 C., the traverse being suilicient for a one minute immersion. From the vat 3, the tube is passed between a pair of squeegee rollers 4 which remove the surface liquid. The tube is passed next into a vat 5 which may contain a saturated aqueous solution of lead acetate maintained at a tem perature of about 40 C. As the tubing passes through vat 5, the lead acetate reacts with the sodium dichromate to form in situ throughout the gel a. precipitate of lead chromate. It is to be understood that the vat 3 and/or the vat 5 it is subjected to the usual softening and drying into a vat is equally applicable "for the printing of sheets,

may be replaced by a printing unit by which the article will be impregnated withthe pigment in predetermined areas only. The pigmented tube is now washed .in one or more vats 6. The squeegee rollers 4 remove the surface liquid as the tube passes into a conditioning vat 8 which contains,

dyestuff solvent then passes through the printing unit designated generally as 9 and which may comprise a heated roller ID, a pair of printing rollers ii and i2 between which the tube passes, the roller i2 being provided with a raised design to which ink is applied from the inking rolls i3,

and II, of which the latter dips into a receptacle i5 containing the ink. It the tubeis to be severed into sections to form closurebands, it is preferable to cut the tube immediately after printing, for example, at the'point C in Fig. l.

After the printing operation, the printed material may be and preferably is aged for a time sufilcient to'produce the' desired penetration of the dyestufi, into the hydrogel. The penetration may be accelerated,- for example, by heating the printed material for about one minute or longer according to the penetration desired. For this purpose, the printed tube maybe passed into and fes'tooned in a chamber 90 C., the traverse being completed in one minute. In lieu of heating, the material may be allowed to stand in air for a longer period of time. During the ageing, the dyestuif solvent should not be completely removed. Further, the penetration of the dyestufi is promoted by the presence of the pigment, and of the solvent in the hydrogel.

Immediately after the ageing operation, the

printed tube may be and preferably is immersed in a salt solution which renders the dyestufl insoluble and thus prevents smearing and bleeding of the indicia. For example, the tube may be passed through a vat 1 containing a 5%-10% aqueous solution of calcium chloride. After the salt treatment, the printed tube may be passed i8 containing water which washes off any excess ink and extracts the residual dyestuif solvent.

The printed material vat l9 containing a 3% aqueous may now be placed in a solution of formaldehyde maintained at a temperature of from 60 to 90 C. for about 30 minutes. The tube is then given a final washing with water containing a small amount of an alkali ;to neutralize any acid remaining in the material. The printed and washed tube, which is still in a gel state, may be employed as sausage casing and in this event,

treatments.

Alternatively, the printed tube i may be severed along lines -20, as shown in Fig. 2, to form a shrinkable closure band 2|, such as that illustrated in Fig. 3. When destined for use as bands, it is preferable to cut the tube as soon as possible after the printing operation, for example, at the point C shown in Fig. 1. The subsequent treatments of ageing, salting, washing and fixing may then be carried out as separate batch operations.

It is to be understood that the process is not 16 heated to from 60 to films and hollow bodies, such. as capsules, in par- E'ig. 4.

It has been suggested above that the hydro philic colloid may be impregnated with-the opaque inorganic pigment only in predetermined areas.

The pigmenting process may be simplified by printing with an ink containing the second inorganic substance, reagent B, upon a material previously treated with the first inorganic substance, reagent A. Thus, the material'is first treated with reagent A, conditioned with the dyestuif solvent, the surface liquid removed and the material then printed with an ink comprising a suitable'dyestuif, reagent B and suitable solvents for the dyestuff and the reagent. With this procedure the opaque inorganic compound is formed in situ, and the gel simultaneously dyed. The indicia so produced are characterized by high opacity, good penetration and sharp outlines.

It has also been discovered that the intensity of color and density of the indicia may be iurther increased by converting the deposited insoluble inorganic compound into a black sulphide within the areas comprising the indicia. This modification of the process is illustrated by the following examples:

. Example I.

A bottle cap of regenerated cellulose-is impregnated throughout with lead carbonate, conditioned with the dyestuif solvent and, after removal of the surface liquid, is printed with an ink containing: Benzoform blue, sodium sulphide (1%) monoethyl ether of diethylene glycol, water and glycerine. The printed cap. is then washed, the dye fixed with formaldehyde solution, and the cap finally washed with water having a slight alkaline reaction. The sodium sulphide in the ink converts the lead carbonate into black lead sulphide.

Example II A sheet of regenerated cellulose is impregnated with lead acetate and with a dyestufi solvent. and then printed with an ink of the following type: Benzoform color, sodium carbonate, monobutyl ether of diethylene glycol, water and diethylene glycol, and thereafter finished in the manner herein described. In this example, the sheet remains transparent, but is both dyed and impregnated with an opaque deposit of white lead carbonate in areas comprising the indicia.

Since certain changes in carrying out the above process, and certain modifications in the article which embodies the invention may be made without departing from its scope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

- 1'. A process for producing an indicium on a pellicle of a hydrophilic colloid comprising impregnating such a colloid with an organic water-miscible dyestuff solvent which is a swelling .agent for the colloid and a water-soluble inorganic substance, and printing the thus impregnated colloid in gel state in the presence of heat with an ink containing a substantive dyestufl,

ticular shrinkable closure caps 22, as shown. in

a water-miscible solvent therefor and a second wetter-soluble inorganic substance capable oi reacting with said first applied inorganic substance to form in situ an insoluble inorganic compound.

2. A process for producing an indici on s peilicie oi a hydrophilic colloid, comprising impregnsting such a colloid with on organic woter=miscible dyestufl solvent which is s swelling agent for the colloid and a water-soluble inorganic substance, removing surface liquid from said impregnated colloid, heating and printing the thus impregnated colloid in gel state with an ink containing a substantive dyestufi, a watesmiscible solvent therefor and c second water soluble inorganic substance capable of reacting with said first applied inorganic substance to form in situ an insoluble inorganic compound, ageing the printed material and insolubilizing the dyestud.

3. A process for producing an indicium on n pellicle of a hydrophilic colloid comprising impregnating such a, colloid with an organic we tor-miscible swelling agent which is a solvent for substantive dyestufis and a water-soluble inorganic substance, and impregnating the colloid with a second water-soluble inorganic substance and a dyestufi, said dyestuif being applied to a predetermined area and the second inorganic substance being capable of reacting with the first inorganic substance to form in situ an in= soluble inorganic compound.

oneness d. A process for producing an indicium on s pellicle of a hvdrophilic colloid comprising treat ing such a pellicle with s, dilute aqueous solution of en inorganic compound, treating the colloid with e. relatively concentrated aqueous solution of a second inorganic compound which reacts with the first compound to form a water-insoluble inorganic compound within the pellicle, impresnating the pellicle with an organic watermiscible swelling agent which is a solvent for substantive dyestuds and printing the thus treated pellicie in gel state with an ink containing a substantive dyestufi and a water-miscible solvent therefor.

5. A'process for producing an indicium on a pellicle of a hvdrophilic colloid comprising treating such a pellicle with a dilute aqueous solution of an inorganic compound, treating the colloid with. a relatively concentrated aqueous solution I of at second inorganic compound which reacts with the first compound to form a water-insoluble inorganic compound within the pellicle, impregnating the pellicle with an organic watermiscible swelling agent which is a solvent for substantive dyestuffs, removing surface liquid from said impregnated colloid and printing the thus treated pellicle in gel state with an ink containing a substantive dyestufi and a water-miscible solvent therefor, aging the printed material and insolubilizing the RALPH T. K. CORNWEIL.

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