US3336156A - Copolymer vinylpyrrolidone vinylacetate film former for coating or printing on water soluble films - Google Patents

Description

United States Patent COPOLYMER VINYLPYRROLIDONE VINYLACE- TATE FILM FORD [ER FOR COATING 0R PRINT- ING 0N WATER SOLUBLE FILMS James'J. Gannon, Florham Park, N.J., assignor to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed May 20, 1963, Ser. No. 281,817

1 Claim. (Cl. 117--138.8)

This invention relates to a film former and lacquer vehicle for coating or printing on water soluble films. More particularly, this invention relates to a new use for a film forming lacquer vehicle containing a vinyl pyrr-olidone copolymer. Specifically, this invention relates to a film-forming lacquer vehicle containing a vinyl pyrrolidone copolymer for coating or printing on water soluble films and to a process for making and using the same.

It is a current trend among home and industrial products manufacturers to sub-package or encapsulate their products in individual ready-to-use units or immediate use size capsules with the aid of water soluble films. These capsules are so designed that the individual consumer may simply select one from a larger container or dispenser and drop the same into any aqueous bath to be treated. Thus, the encapsulated product rapidly becomes available as the water soluble film covering the encap sulated product dissolves. The commercial acceptability of encapsulated products has been excellent in the case of the individual consumer due to the ease of use. Industrial acceptance of water soluble film packaged products is also growing since this technique facilities the handling and measuring of specific quantities of chemical reactants, pigments, fillers and other industrial additives. Photographic chemicals have also been packaged in this fashion, enabling the user to quickly prepare a bath of the correct concentration merely by adding one or more capsules of the chemicals to a given quantity of water.

In the case of encapsulated home laundry products, such packaging techniques will relieve the housewife of the task of measuring and handling detergent, bleach, dyestufi, water softener or other powdered products. The use of encapsulated products may be necessary for, and provide relief to allergy sulferers by protecting them from laundry detergents and the like. Moreover, this form of encapsulation is also economical, eliminating spillage and waste due to unnecessary overdosage. Further, encapsulation eliminates the hard-to-handle characteristics of powdered laundry aids and improves the speed and efiiciency of the housewife.

From a more commercial standpoint, the Water soluble film packaging of laundry products will greatly aid the vending machine sale of detergent, bleach and blueing aids in automatic laundries. Further, the need for disposal of package wrappings will be eliminated. Moreover, with the use of water soluble films, various harmful, cumbersome and hard-to-handle reactants, pigments and other ingredients can be supplied in accurately measured and easy-to-handle amounts, greatly facilitating the speed and efliciency of industrial operations while providing for easier quality control and more uniform products.

It is known to package a variety of products in readyto-use water soluble film type containers. These products include bubble bath, toilet bowl cleaner, household dye, starch, water softeners, agricultural chemicals, swimming pool additives, tints for vinyl-latex water base paints, septic system conditioners, anti-rust agents for automotive cooling systems, industrial additives, photographic chemicals, bath powders, and water soluble rope. Water soluble film enclosed packages are also being used in the foodpackaging industry.

3,336,156 Patented Aug. 15, 1967 Therefore, it is desirable today with the wide use of water soluble film packaged products to print the product name, the name of the producer, various pertinent directions, the ingredients, etc., directly on the water soluble film covering the encapsulated product in order to positively identify the product being used by the consumer, and to eliminate the possibility of mistake should the original shipping package become lost or mutilated. In some instances it may be desirable to coat a unit-packaged product with an agent that will react with or modify the action of the primary encapsulated product. Furthermore, the printing of names, directions, etc., on the packaged product may be necessary in the interests of economy and efficiency when products of the type described herein are intended for rapid and etficient merchandising as, for example, in the case of vending machine distribution.

Heretofore, the printing of indicia onto water soluble films has presented a number of problems. If a water base printing paste is used, it introduces the inherent complicating effect of redissolving the water soluble film on which the printing application is to be made. Redissolution of the base film warps and obliterates the printing and in some instances destroys the base film itself. Any form of quality control of product appearance has become extremely difficult and is often impossible.

In the case where a non-water base printing paste is employed to eliminate the redissolution problem, it has been found that the resultant printed indicia are not water soluble and may inhibit or even prevent the dissolution of the water soluble film itself. In the case of food products, non-water base printing pastes may have a disagreeable taste or exert a harmful or poisonous effect on the consumer.

The over-coating of water soluble films with a reactant or modifying agent presents a somewhat lesser problem since many non-water base coating vehicles are commercially available. However, these non-water base coating vehicles are usually not water soluble themselves. Thus, if a Water soluble film encapsulated product, such as a laundry detergent, is coated in the usual manner with a coating solution containing a bleach, the entire encapsul ated product will be prevented from water dissolution by the overcoating vehicle.

It is therefore an object of this invention to provide a new printing or coating vehicle.

Another object of this invention is to provide a printing or coating vehicle suitable for use on water soluble films.

Still another object of this invention is to provide a printing or coating vehicle for water soluble films which will not have the inherent disadvantage of redissolving the water soluble film on which the printing or coating application is made.

A further object of this invention is the production of a printing or coating vehicle for Water soluble films, wherein the vehicle itself is water soluble.

It is still a further object of this invention to produce a water soluble printing or coating vehicle containing a water soluble copolymer of polyvinylpyrrolidone.

Other and further objects of this invention will become readily apparent to those skilled in the art from the following description and claim.

The objects of this invention are accomplished by providing a volatile organic solvent solution of a polyvinylpyrrolidone copolymer. More particularly, the objects of this invention are accomplished by providing a polyvinylpyrrolidone copolymer vehicle containing a coating or printing agent in volatile organic solvent solution. In this manner, a printing or coating vehicle is provided that does not have the inherent complicating defect of redissolving the water soluble film on which the printing or coating application is made, and yet retains the property of providing a completely water soluble product. Accordingly, the water soluble product of this invention will be soluble in water solutions at any temperatures and pressures that are common to commercial, industrial and household applications.

The water soluble copolymer from which the printing or coating vehicle of this invention is prepared is a copolymer of vinylpyrrolidone (N-vinyl-2-pyrrolidone) with copolymerizable monomers whose homopolymers have a water insoluble, flexible character, such as vinyl acetate, acrylic acid esters (e.g., ethyl acrylate) and mixtures of vinyl acetate and acrylic acid ester. Generally, a copolymer prepared from 30 to 98 of N-vinyl-Z-pyrrolidone with one of these copolymerizable monomers will produce an acceptable result. Surprisingly, the use of such comonomers as vinyl acetate or ethyl acrylate will provide a means for adjusting copolymer film flexibility, and will permit the adjustment of humidity resistance of the copolymer product while still retaining the necessary degree of water solubility in the same.

In accordance with this invention the printing or coating lacquer vehicle is prepared by dissolving the polyvinylpyrrolidone copolymer in a suitable volatile organic solvent. By providing a volatile organic solvent base, applicants vehicle will function as a fast-drying lacquer that will not dissolve water soluble films upon which the vehicle is coated or printed. It is obvious that various pigments, dyestuffs and other coating agents may be added to this lacquer vehicle in either dissolved or dispersed form since the same will be held in place on a water soluble film base by the holding action of the vinylpyrrolidone copolymer resin. Potentially unstable additives, catalytic agents, etc., can be incorporated into the lacquer vehicle and give coincidental isolation from any premature interaction with the ingredients contained within the water soluble film. The additives therefore, may be water soluble or water insoluble, depending on their resultant function when the water soluble film packaged products is to be used. In this manner, the utility of the lacquer vehicle of this invention as a coating vehicle or carrier for coating materials, is practically unlimited and comprises additional incentive for using water soluble film packaged products.

In forming the lacquer vehicle of the instant invention, the solvent for the copolymer resin may be an alcohol, ketone, chlorinated hydrocarbon, or an aromatic hydrocarbon, such as the solvent naphthas. The particular solvent chosen and the amount used depends on the viscosity desired for the solutions made therefrom, and the evaporation rate thereof.

In the instance of a printing ink, the utility of the lacquer vehicle of this invention is limited only by the resin used, the type of solvent for the resin, the dyes, the solvent for the dyes, and the viscosity of the ink. The success of the normalization of the printed product of this invention is dependent upon the diffusibility of the dyestuif into the resin sheet. The diffusibility is a property of the dyestuff used and does not appear to be influenced by the solvents and plasticizers used in preparing the ink. The solvent for the dyestuff may be, for example, a ketone or chlorinated hydrocarbon. In some cases, the same solvent, such as cyclohexanol, may be used for both the dye and the resin. In this connection, the choice of dye solvent will depend upon the compatibility with the resin solvent, viscosity characteristics, evaporation rate, etc.

Presently, polyvinyl alcohol (modified or unmodified), polymerized methyl cellulose and polyethylene oxide are in common use as water soluble films for the packaging of ready-to-use products. Of these water soluble materials, polyvinyl alcohol is most commonly used due to its low cost, commercial availability and desirable physical and chemical properties. If desired, it can be commercially obtained in a harmless and non-toxic form and is readily soluble in both hot and cold water. Applicants have found in this invention that their lacquer vehicle, consisting of an organic solvent solution of vinylpyrrolidone copolymers, comprises an excellent coating and printing vehicle for modified or unmodified polyvinyl alcohol films. Due to the present wide usage of polyvinyl alcohol water soluble film, this invention is primarily concerned with the coating and the printing of the same although not necessarily limited thereto.

The coating and printing compositions of this invention can be applied to the water soluble film substrates by any of a variety of mechanical systems well known in the art. For exam le, the coating may be applied by dipping, spraying, mist or fog deposition, or by foaming and calendermg.

Details of suitable lacquer vehicle formulations, and the production of the related coating and printing vehicles from such formulations, as well as processes for the coating and printing of products, are apparent from the following examples, although these examples are given by way of ilustration only, and are not intended as limitative on the scope of this invention.

EXAMPLE 1 Printing vehicle preparation A typical lacquer printing vehicle, designed to provide identification and printed directions on water soluble films, was prepared as follows:

Grams Neptune Blue Bra Conc. (Part H, New Cl 42090) 1.0 Denatured alcohol 8.0

The dyestuff was gradually dissolved into the appropriate amount of organic solvent to form a solution of dyestuff. The dyestutf solution was then gradually added, with stirring, to the organic solvent copolymer solution to obtain a vehicle which was suitable for a printing application on water soluble films without causing undesirable dissolution of the same. In this connection, a powdered laundry detergent was packaged in various water soluble films such as polyvinyl alcohol, methyl cellulose, polyethylene oxide. Thereafter these water soluble films were coated with the above prepared vehicle so that the producers name, directions for use, and various other indicia were clearly and distinctly visible on the water soluble film itself. After drying of the vehicle, the entire product (detergent, water soluble film and dried printing vehicle) was soluble in water.

EXAMPLE 2 Printed product preparation A quantity of a typical laundry detergent powder, designed for ordinary home laundry use, was spread onto a tablet mold and the detergent powder was compressed into a number of laundry size detergent tablets. An alcohol solution of a water soluble polyvinyl alcohol resin was prepared in a manner well known in the art and placed in a spray gun. The detergent tablets were spray coated on both sides and permitted to dry. Thereafter, rubber stamps, containing both large block letters and letters representative of fine newsprint size, were dipped into a printing vehicle prepared in a manner similar to that of Example 1 above, and the polyvinyl alcohol coated detergent tablets were then imprinted with the printing vehicle carrying stamps. The tablets were permitted to dry and they were examined continuously from the time of imprinting vehicle or distortion of the polyvinyl alcohol film was observed. The printing was clear and distinct. The tablets were then dropped, individually and with stirring into buckets filled with warm water. Within a very short time it was noted that the printing vehicle, the polyvinyl alcohol and the detergent had completely dissolved.

EXAMPLE 3 Coated product preparation A quantity of powdered laundry detergent in admixture with a quantity of dyestuif was compressed into tablet form and coated with a water soluble polyvinyl alcohol film in a manner similar to that employed in Example 2. A coating vehicle, containing a large quantity of powdered laundry bleach was prepared by first preparing a slurry of 20 grams of sodium perborate in 80 grams of denatured alcohol and adding this slurry to 40 grams of a 50% solution in isopropanol of a vinyl pyrrolidonevinyl acetate cpolymer (70% vinyl pyrrolidone, 30% vinyl acetate by weight). It was noted however, that the bleach powder did not completely dissolve in the volatile solvents employed even with repeated agitation, but remained in a finely divided state. The coating vehicle was of a syrupy consistency. The polyvinyl alcohol coated tablets were dipped into this syrupy fluid and suspended in a current of warm air until dry. The coating had a cloudy, translucent appearance due to the particulate form of the bleach. It was noted that none of the dyestulf in admixture with the detergent had migrated'into the bleach coating layer. The coated tablets were then dropped, individually, and with stirring, into buckets filled with warm water. Within a very short time, it was noted that the coating vehicle, the bleach, the polyvinyl alcohol, the dyestuff and the detergent had completely dissolved.

EXAMPLE 4 Preparation of coating containing laundry blueing aid A typical coating, designed to carry a blue dyestuff which (I) initially serves as an ink color for package identification and directions and (2) subsequently becomes the laundry blueing aid, was prepared as follows:

Patent Blue VF Ex Conc. (Part II, New CI 42045) grams Denatured alcohol ml Isopropanol solution containing fifty (50) percent of vinyl pyrrolidone-vinyl acetate copolymer (containing 70% by weight of vinyl-pyrrolidone and 30% by weight of vinyl acetate) grams 40.0

EXAMPLE 5 Preparation of coating containing laundry germicide A suitable formulation, designed to provide germicidal activity in a laundry product may be prepared as follows:

Polyvinyl pyrrolidoneIodine CompleXPVPI 20(containing 20% available iodine).. grams Denatured alcohol ml Isopropanol solution containing (50) pearcent of vinylpyrrolidone-vinyl acetate copolymer (containing 50% by weight vinyl pyrrolidone and 50% by weight vinyl acetate) grams 40.0

The ten gram quantity of PVP/I 20 was gradually dissolved in the 10 milliliters of denatured alcohol to form a concentrated germicide solution. This germicide solution was gradually added to the forty gram isopropanolcopolymer solution with stirring to obtain a coating or printing vehicle suitable for the printing of indicia onto a water soluble film. This mixture will provide germicidal activity for a laundry product when it is either coated or printed onto a water soluble detergent package.

It will be obvious from the foregoing examples that the same procedures may be followed in preparing printing or coating vehicles werein the copolymer employed is a copolymer of vinyl pyrrolidone and an acrylic acid ester (such as the esters of acrylic, ethylacrylate and methacrylic acid) or a terpolyrner of vinyl pyrrolidone, vinyl acetate and an acrylic acid ester. Similarly, solvents such as alcohols, ketones, chlorinated hydrocarbons, or aromatic hydrocarbons may be substituted for the isopropanol and denatured alcohol solvents employed in the examples.

It is obvious that many variations and changes may be made in the products and processes of this invention, without departing from the spirit and scope thereof. It is merely intended that this invention be limited to the scope set forth in the following dependent claim.

What is claimed is:

A process for producing a water soluble printed coating on a water soluble film without adversely affecting the Water soluble film so as to produce a completely water soluble product which comprises applying to a water soluble film of polyvinyl alcohol a lacquer Vehicle comprising an isopropanol solution containing 50% of a vinylpyrrolidone-vinyl acetate copolymer, said copolymer containing from about 50% to about by weight of vinylpyrrolidone, denatured alcohol, and a dye selected from Neptune Blue Bra Concentrate (Part II, New Color Index 42090) and Patent Blue VF Ex Concentrate (Part II, New Color Index 42045), the ratio of isopropanol solution to denatured alcohol to dye being 40:8:1.

References Cited UNITED STATES PATENTS 1,8 67,117 7/1932 Tengler 252-90 2,908,650 10/1959 Fine 252- 3,068,151 12/1962 Haefele 16787.1 3,071,558 l/l963 Jafie et al. 260 33.4 3,073,794 1/1963 Stoner 260-318 3,076,776 2/1963 Findlay 26033.4

OTHER REFERENCES Smith, W. M., Vinyl Resins, 1958, N.Y. Reinhold Publishing Company (pp. 55-57, 264-265 relied on).

Schildknecht, C. E., Vinyl and Related Polymers, 1952, John Wiley and Sons, Inc. (pp. 674-75, 677 relied on).

JULIUS FROME, Primary Examiner.

A. T. MEYERS, A. HOLTZ, Assistant Examiners.

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