US2320510A - Process of printing and article produced thereby - Google Patents

Description

Patented June 1, 1943 PROCESS OF PRINTING AND ARTICLE PRODUCED THEREBY Ralph T. K. Cornwell and Charles M. Rosser,

Fredericksburg,

and John A. Your-tee. Falmouth, Va., assignors to Sylvania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia No Drawing. Application January 7, 1939,

Serial No. 249,728

Claims.

The present invention relates to the art of printing. More particularly, it relates to a process of printing non-fibrous pellicles, particularly of the water-swelling type, and to ,a composition of matter which is capable of use in the printing operation and an article of manufacture produced by the process.

In the printing of non-fibrous pellicles heretofore, two types of ink have been employed. The first has been of the so-called flash drying type which has enabled the pellicles to be rapidly printed and stacked one on top of the other without smearing, but this type of ink has not been capable of tightly anchoring itself to the pellicle so that it could withstand immersion in water without separating from the pellicle. The second type of ink has been the water-resistant type which is capable of anchoring itself to the pellicle so as to remain attached to the pellicle when the same is immersed in water, but this type has always been slow drying which has made it impossible to stack printed pellicles one on top of the other, or to permit the printed surface of a pellicle to come in contact with any other object for several hours following printing. Thishas necessitated printing the pellicles in separate sheets or short pieces and the use of separators, commonly called slip-sheets, between the sheets or pieces if they were stacked one on top of the other to prevent the printed surfaces from smearing or ofisetting. Such printing procedures have been slow and consequently expensive.

It is a general object of the present invention to provide a new and useful process of printing pellicles.

It is a'specific object of the present invention to provide a process of printing water-swelling, non-fibrous pellicles with a quick-drying ink to give a deposit which is strongly adherent and Water-resistant when the printed pellicle is immersed in water.

It is a further object of the present invention to provide an ink which is quick-drying and capable of producing a dried deposit which will adhere tenaciously to a water-swelling pellicle when the same is immersed in water as well as when it is subsequently dried.

It is a still further object of the present invention to provide an article of manufacture in the form of a water-swelling non-fibrous pellicle provided with a printed area or areas-which will adhere to the pellicle during submersion of the same in water and during and after subsequent drying.

Other objects of the invention will in part be obvious and will in part be pointed out in the following detailed description.

In accordance with the present invention, a non-fibrous pellicle, preferably of the waterswelling type, is printed with an ink comprising a base of an unhardened, heat-hardenable ureaformaldehyde resin, a plasticizer for the resin, a resin-hardening agent, coloring matter and/or pigment and a suitable volatile solvent.

The ink is applied to the pellicle by any suitable printing method, such as typography or intaglio processes, and the pellicle so treated is subjected to an elevated temperature for a few minutes to harden the resin, remove the solvents and render the ink deposit dry, non-tacky and strongly adherent to the pellicle even when immersed in water. If desired, the printing process may be carried out on a continuously operated press, such as a rotary press, after which the printed pellicle is passed through a suitable dryer for a short period of time, and finally wound upon a suitable roller or severed into desired lengths.

The invention accordingly comprises the several steps and relation of one or more of such steps with respect to each of the others, and the composition of matter and articl'epossessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

Pellicles which may advantageously be printed in accordance with the present invention may be formed of non-fibrous cellulosic material such, for example, as, cellulose hydrate regenerated from viscose or cuprammonium cellulose or formed by de-esterifying cellulose esters; cellulose esters, such as cellulose acetate; or cellulose ethers, such as alkyl or hydroxy-alkyl cellulose ethers; alsomixed esters, mixed ethers and ether-esters of cellulose. The pellicles may also be formed of casein, gelatin, and other similar materials. The pellicles may be formed in any suitable manner as by casting, moulding, coating, etc. A type of pellicle which is especially applicable for use with the present invention is plasticized cellulose hydrate, commonly known as cellophane, which may be in the form of sheets, strips, tubes or caps.

The pellicles may be plasticized with any well known type of plasticizer dependin upon the nature of the pellicle. It is preferred, however, that the pellicles be plasticized with one of the following materials: glycerin, sorbitol, sugar solutions, di-ethylene glycol, etc. It is preferred that the pellicle be printed after it has been plasticized and d ed on the surface. In other words, the surface of the pellicle at the time of printing should be free of liquid and in a dry state, although the interior of the pellicle need not be fully dried.

The ink of the'present invention comprises a base of urea-formaldehyde resin which is soluble in organic solvents. The resin should be in an intermediate or organic solvent soluble stage, that is, in an unhardened state at the time of printing. Suitable urea-formaldehyde resins for use in accordance with the present invention are sold commercially under the trade names "Beckamine," "Beetle" and Uformite." Urea formaldehyde resins of the foregoing types are characterized by being convertible to the hard and insoluble state by heating them in an acid medium or with suitable acid-forming substances or catalysts.

The ink is provided with a plasticizer which renders it flexible when dry and capable of expanding and contracting with the pellicle. Suitable plasticizers are resins of the soft type, such as polymerized unsaturated hydrocarbons, for example, polymerized iso-butylene which is commonly sold under the trade name "Vistanex"; alkyd resins of the type formed by the condensation of polyhydric alcohols and dibasic organic acids, such as that sold under the trade name BeckasoP'; vegetable oils of the drying type, such as linseed oil, or the semi-drying type, such as cotton seed oil, or of the non-drying type. such as castor oil, and organic plasticizers, such as dibutyl sebacate, di-butyl phthalate, tri-cresyl phosphate, etc. The plasticizer is employed in an amount ranging from about 10% to about 30% by weight of the urea-formaldehyde resin.

To facilitate the rapid drying of the ink, there is preferably employed in the ink an agent which promotes the rapid hardening of the urea-formaldehyde resin, such as an acid or an acid salt, for example, ammonium salts, such as ammonium thiocyanate, ammonium sulphate, ammonium phosphate, or ammonium acetate, and organic acids, such as malic, maleic and citric acid. The hardening agent comprises about 2% to about preferably about 3%, by weight of the ureaformaldehyde resin. The quantity employed may be varied, depending upon the desired rate of drying of the ink. As hardening agents, suitable catalytic materials may be employed to bring about rapid hardening of the resin such, for example, as that sold under the designation Catalyst Z," by the Resinous Products and Chemical Company, Inc.

The ink may be colored by the addition of suitable coloring materials in the form of pigments or dyestufl's. Pigments and dyestuffs may be selected in accordance with the desired coloration of the ink and may be employed in an amount sufiicient to produce the desired coloration.

As an ink solvent or liquid vehicle, there may be employed an organic solvent or solvent mixture which will evaporate rapidly at slightly elevated temperatures, for example, 80 to 90 C., and the solvents may be selected from the lower aliphatic or aromatic hydrocarbons, lower alcohols, lower esters, ethers, etc. In the now preferred embodiment of the invention, the ink solvent comprises a mixture of toluene, butyl alcohol and ethers of ethylene glycol. The ratio of solid ingredients to solvent will be dependent upon the specific printing operation employed,

used and the density of the deposit required, the speed of printing, etc.

Immediately following the application of the ink to the pellicle, it is passed through or into a heated atmosphere or heated air is passed over it to evaporate the solvent and to convert the resin from the intermediate to the hard or insoluble state. The temperature employed will depend upon the period of treatment, but a temperature of 80 C. will be sufficient for a heating period of about 3 to 4 minutes. In general, the higher the temperature, the shorter the heating period may be, but it is advisable to keep the temperature below a point sufiicient to cause embrittlement of the pellicle.

The following example will be given by way of illustration but not in limitation of the invention:

A pellicle of cellulose hydrate plasticized with glycerine, sorbitol or with some one of the other having in mind the kind of printing apparatus plasticizers heretofore mentioned is supported upon the platen of a press or is passed continuously through a rotary press and is printed with an ink comprising:

50 parts of solid mixture consisting of:

Parts Base: Urea formaldehyde resin 40 Plasticizer: Alkyd resin 16 Hardener: Ammonium thioeyanate 3 Pigment: Titanium oxide 5 and 50 parts of a solvent mixture comprising:

Parts Toluene 90 Butyl alcohol Y 5 Ethylene glycol mono-ethyl ether 5 The printed pellicle is immediately passed into a dryer or some other suitable heating device and subjected to a temperature of about for 3 to 4 minutes, for example, by passing it in restooned condition through a heated chamber. At the end of this period the ink will be found to be nontacky, strongly adherent to the pellicle when the same is immersed in water and to be durable and resistant to conditions of use and have a high gloss. The printed pellicle can be immediately wound into a roll or cut into suitable lengths and stacked without slip sheets as it leaves the printing machine without smearing the ink. This enables pellicles to be rapidly printed with the result that the expense and trouble of printing is necessitating the use of separators, such as "slipsheets, to prevent overlapping sections of the pellicle from smearing the printed areas and at the same time the deposit produced will tenaciously adhere to the pellicle when the same is immersed in water and during and after drying of the same. 'I'heprinted deposit is resistant to wear and has an attractive and permanent gloss Pellicles in tubular form which are of the type capable of use as artificial sausage casings or container closures can be advantageously printed by the process and ink of the present invention, as well as sheets and pellicles in other forms.

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

The invention having been disclosed, what is claimed is:

1. A printing ink for use on nonfibrous, waterswelling pelliclos comprising organic solvent soluble urea-formaldehyde resin, an alkyd resin, ammonium thiocyanate and a coloring agent. dissolved in a solvent comprising toluene, butyl alcohol and ethylene glycol mono-ethyl ether.

2. The process of printing non-fibrous waterswelling pellicles comprising supporting the pellicle and printing thereon with an ink comprising an organic solvent soluble, heat-hardenable urea-formaldehyde resin, and subjecting the printed pellicle to heat to harden the resin and adhere the printing to the pellicle, whereby the printing remains adherent when the latter i immersed in water during and subsequent to dr mg. I

3. The process of printing non-fibrous waterswelling pellicles comprising supporting the pellicle and printing thereon with an ink comprishardenable, urea-formaldehyde resin and a plasticizer, and subjecting the printed sausage casing to heat to harden the resin and adhere the printing to the sausage casing, whereby the printing remains adherent to the sausage casing during immersion in boiling water incidental to cooking or when the casing is subjected to smoking of the type used in curing operations, as well as during and subsequent to drying.

7. The process of printing artificial sausage casings formed of nonfibrous, water-swelling material comprising supporting the casing and printing thereon with an ink comprising a heathardenable, urea-formaldehyde resin, a plasticizer and a hardening agent for the urea-formaldehyde resin, and subjecting the printed sausage casing to heat to harden the resin and adhere the printing to the sausage casing, whereby the printing remains adherent to the sausage casing during immersion in boiling water incidental to cooking or when the casing i subjected to smoking of the type used in curing operations, as well as during and subsequent to drying.

8. An article of manufacture, a pellicle formed of non-fibrous, water-swellingmaterial having a smooth non-porous surface and having a heathardened continuous printing ink deposit on said surface formed originall -of an organic solventing an organic solvent soluble, heat-hardenable urea-formaldehyde resin and an alkyd resin, and subjecting the printed pellicle to heat to harden the resin and adhere the printing to the pellicle, whereby the printing remains adherent when the latter is immersed in water during and subsequent to drying. I

4. An article of manufacture comprising a pellicle formed of non-fibrous cellulosic material and an ink thereon formed originally of an organic solvent soluble urea-formaldehyde resin, which ink adheres to the pellicle when immersed in boiling water or subjected to fumes of the type utilized in the curing of sausages.

5. As an article of manufacture, an artificial sausage casing formed of nonfibrous, waterswelling material and a printing ink thereon comprising a heat-hardened, urea-formaldehyde resin and a plasticizer, the urea-formaldehyde resin having been heat-hardened after application of the ink to the sausage casing, whereby the ink adheres to the sausage casing during immersion in water incidental to cooking as well as when the sausage casing is subjected to smoking and drying operations.

6. The process of printing artificial sausage casings formed or nonflbrous, water-swelling material comprising supporting the casing and printing thereon with an ink comprising a heatoluble urea-formaldehyde resin, and a plasticizer, the urea-formaldehyde resin having been heat-hardened after application of the ink to the pellicle, whereby the ink adheres to the pellicle during immersion in water and during and subsequent to drying.

9. As an article of manufacture, a pellicle formed of non-fibrous, water-swelling material having a smooth non-porous surface and having a heat-hardened continuous printing ink deposit on said surface formed originally of an organic solvent-soluble urea-formaldehyde resin, and an alkyd resin, the urea-formaldehyde resin having been heat-hardened after application of the ink to the pellicle, whereby the ink adheres to the pellicle during immersion in water and during and subsequent to drying.

10. .As an article of manufacture, a pellicle formed of non-fibrous, water-swelling material having a smooth non-porous surface and having a heat-hardened continuous printing ink deposit on said surface formed originally of an organic solvent-soluble urea-formaldehyde resin, a plasticizer and a coloring pigment, the urea-formal dehyde resin having been heat-hardened after application of the ink to the pellicle, whereby the ink adheres to the pellicle during immersion in water and during and subsequent to drying.

RALPH TIK. CORNWEL'L. CHARLES M. ROSSER. JOHN A. YOURTEE.