US2353717A - Process and article for treating materials and article so produced - Google Patents

Description

Patented July 18, 1944 units ST PATENT OFFEC PROCESS AND ARTICLE FOR TREATING MATERIALS AND ARTICLE. S PRODUCED No Drawing. Application July 19, 1940, Serial No. 346,332

lllainis.

The present invention relates to the art of finishing. More particularly, it relates to a process of finishing in which a film is formed and transferred to an article for the purpose of decorating, varying the visual characteristics of the article, preserving and/or strengthenin the article. The invention also relates to the transfer article by which the film is applied to the article to be finished and to the finished article.

It is desirable that many articles such as magazine covers, pictorial and other advertising pages, prints, photographs, maps and covers for books and pamphlets be provided with finished surfaces in order to enhance their appearance and durability. However, the attainment of this object by the application to the articles of a film capable of producing this result presents many difiicult problems. Such finishing films should be capable of producing coloration, as desired, to

produce a, decorated efiect or of being made translucent to provide a softening or toning effect. Such films should also be capable of being made clear and transparent so as to increase the brilliance of the surface reflection or to clarify details of the articles, and for these purposes the films must have smooth and glossy surfaces which makes the problem even more difiicult. It is frequently necessary also that such a film serve to reinforce the article as well as protect it against defacement, either through accidental sources, such as wear, scratching or the like, or intentional alteration.

Since many of these articles, for example, magazine advertisements or other advertising or decorative matter, depend almost entirely upon an attractive appearance for their effectiveness, it naturally follows that anything which increases the attractive properties of these articles enhances their functional value. For this reason,

the applied film must be capable of impartinga high gloss to the article and to accomplish this the exposed surfaces of the applied film must be exceptionally smooth and free from blemishes. Also, the films must be of substantially uniform thickness throughout in order to avoid uneven reflections of light and consequent distortion in the appearance of the article. This uniformity of thickness is also necessary if the applied films are to function properly to accentuate and clarify details of the designs, pictures or the like carried by the base sheets beneath the films. Furthermore, such finishing films must be stable, both in appearance and Wearing properties, and to that end must tenaciously adhere to the articles so as to prevent variations in reflective properties, and must in most cases remain transparent and unaffected by light if the appearance of the finished article is to be preserved. Since such finishing films are positioned on the outermost portions of articles, they must be suificiently flexible to bend with the articles without becoming separated therefrom and must also be tough and strong so as not to be readily torn or otherwise deformed.

The process of producing such a finish must be simple in character and the finish itself must be formed from inexpensive and readily available materials in order to prevent the cost from rendering the finish incapable of general application, since many of the articles to which such a finish could be advantageously applied are relatively inexpensive articles of commerce. To this end, the process should be marked by an absence of expensive and complicated apparatus and must make it possible to deposit a very thin film so as to avoid the use of excessive quantities of finishing material and unduly thickening the articles so finished. In this connection, it should be noted that the use of inferior grades of base material, such as paper, chip board and the like may be employed and provided with any desired design since the finishing film fills up and evens out the inequalities in the surface of the articles. Thus, the film must completely compensate for the inferior original quality of the article and additionally strengthen and reinforce the article to enable it to withstand the conditions which it will encounter while in use.

Many articles which can be advantageously finished in accordance with the present process are subject to staining, dissolution of printing ink and the like by solvents and water, and for this reason the'process must be capable of use without employing organic solvents and water. Furthermore, certain finished articles may be brought into contact with foodstuffs and the like, and for this reason the articles must be free from odors frequently attendent with the use of volatile organic solvents.

Since the use of separate adhesives adds materially to the expense and complexity of the finishing operation and frequently leads to the production of inferior articles, it is desirable to avoid the use of adhesives in the finishing process. On the other hand, the finishing films must tenaciously adhere to the articles and to this end the finishing film itself must become very tacky at the time of application, at least throughout the area contacted by the article so as to be capable of adhering to the article, but at the same time must not adhere to anything else so as to deleteriously affect the smooth exterior surface of the finishing film.

It has been found that all of the foregoing desirabilities can be obtained in a facile manner by the use of materials which are inherently thermoplastic and therefore quite tacky when heated to form decorative, protective and/or reinforcing films on an infinite number of articles by forming a film initially on a backing sheet formed of smooth, substantially non-porous material and then transferring the film to the article to be finished by the use of heat and pressure. In this manner, films which are too thin to be able to support their own weight and for this reason could not be formed by extrusion processes and the like, can be formed, handled and transferred without difficulty. Although it would seem that the extreme tackiness of the inherently thermoplastic material at the time of heating incidental to the transfer operation would prevent the material from releasing from the backing sheet, it has been found that these materials will release from backing sheets formed of smooth materials in a clear cut and uniform manner so as to make the application of such films to articles possible at temperatures below those which would damage many delicate articles.

It is a general object of the present invention to provide a process of finishing articles which accomplishes all of the reviously mentioned desirabilities.

It is a specific object of the present invention to provide a process of finishing articles so as to improve their visual characteristics and other physical properties.

It is also an object of the present invention to provide a process of finishing articles with a glossy, mirror-like surface.

It is another object of the present invention to provide a process of finishing articles with a covering of minute thickness.

It is a further object of the present invention to provide a process of finishing articles involving the use of relatively low temperatures to apply the finishing film to articles.

It is a still further object of the present invention to provide an article having an extremely thin finishing coating applied thereto.

It is also an object of the present invention to provide a transfer article in the form of a backing sheet having a film for use in the practice of the process of the invention.

Other objects and advantages, if not specifically pointed out, will be apparent to those skilled in the art as the description of the invention proceeds.

The process of the present invention, in general, comprises suitably applying a layer of inherently thermoplastic material to a backing sheet of smooth, substantially non-fibrous material to form a transfer, contacting the film so formed with an article to be finished, applying heat to the film and/or the article, exerting pressure to force the film into tight contact with the article to cause adherence of the film to the grticle, and stripping the backing sheet from the The articles of the present invention comprise, respectively, a backing sheet formed of smooth material and provided with a layer of inherently thermoplastic material, and a finished article provided with an extremely thin decorative preservative and/or protective coating.

The invention accordingly comprises the sev- 1e resins and the like.

eral steps and the relation of one or more of such steps with respect to each of the others.

and the articles possessing the features, prop-' erties, and the relation of elements, exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

The film-forming material used in the practice of the present invention may be any inherently thermoplastic material, such as synthetic resins, for example, polyvinyl resins such as polyvinyl chloride, polyvinyl acetate and the like; polystyrene, polymerized hydrocarbons such as polyiso-butylene; copolymers, such as copolymers of vinyl halides and vinyl esters, vinyl derivatives and acrylo nitriles, vinyl derivatives and styrene derivatives; acrylic acid esters of aliphatic and aryl alcohols. Thermoplastic cellulose derivatives may also be employed as the film-forming material such, for example, as cellulose esters of the higher fatty acids, such as cellulose stearate, cellulose palmitate, cellulose aceto-butyrate; alkyl and aryl cellulose ethers of high degree of substitution, such as ethyl cellulose and the like. 'The following may also be used: sulfonamide-aldehyde resins; rubber hydrohalides; sulfur-olefin resins; cumarone resin; indene resin; condensation palymers such as the condensation products formed from di-basic acids and diamines (nylon type), and polyhydric alcohols and polybasic acids; chlorinated biphenyls, as well as natural and synthetic gums, and mixtures of any two or more of the aforementioned materials. Materials which are not inherently thermoplastic such, for example, as cellulose acetate, cellulose nitrate and the like, may be mixed in such proportions with inherently thermoplastic materials that the resulting mixture will be inherently thermoplastic and used in the practice of the present invention.

The forming surface on which the thermoplastic materials are spread to form the thermoplastic film are preferably formed of some material which has little or no affinity for the thermoplastic material itself and which is not affected by the solvents and/or plasticizers used in such materials. Such materials are non-fibrous cellulose material such as cellulose esters, for example, cellulose acetate and cellulose nitrate; regenerated cellulose, metal foil, thin sheets of infusible The material which has been found most suitable for this purpose is regenerated cellulose. This may be formed by regeneration of cellulose from viscose or cuprammonium solutions of cellulose, zinc chloride solutions of cellulose, or cellulose dissolved in organic solvents such as quaternary ammonium compounds, or by de-esterification of cellulose esters, de-etherification of cellulose ethers, or gelatinization of cellulose in the form oi cotton linters, wood pulp and the like or from any other source from which regenerated cellulose can be formed. The regenerated cellulose is preferably shaped in the form of a sheet, herein called a backing sheet but may also be formed into a band or plate having a smooth surface upon which the thermoplastic material may be suitably spread. The entire body having the film-forming surface need not be formed of regenerated cellulose and to this end the main portion of the body may be formed of a cellulose ester, a cellulose ether or some other cellulosic derivative which may be suitably treated to convert the surface to regenerated cellulose.

The use of'a non-fibrous material of this type enables the finishing film to have an exceptionally glossy, mirror-like finish since the relatively non-porous and non-fibrous surface of the backing sheet causes the exposed surface of the finishing film to be smooth and highly reflective of light. This greatly enhances the appearance of the finished article. If desired, the smooth surface of the backing sheet may be suitably roughened to cause the surface of the finishing film to be dull instead of glossy,

The backing sheet may be in the form of individual sheets or may be formed as a roll or continuous belt, band or the like.

The inherently thermoplastic material may be disposed upon the film-forming surface of the backing sheet in the form of a molten mass or solution by spraying, brushing, casting, backfilling or the like. From some aspects of the invention, it is preferable that the thermoplastic material be cast upon the transfer sheet in the form of a liquid of controlled consistency. By controlling the solids content and the viscosity of the liquid, the thickness of the film can be accurately controlled to produce a film of substantiallyany desired thickness.

The thermoplastic material may be suitably melted for application to the backing sheet or may be formed into a solution in any manner well known in the art by the use of a suitable solvent for the thermoplastic material. of which there are many well known in the art for all of the thermoplastic materials exemplified above. Likewise, suitable plasticizers may be incorporated in the solution to produce a film having the desired plasticity. The term solution" is used throughout this specification to mean a true solut on, colloidal dispersion or any other liquefaction of the material. such as a molten mass or the like. After the thermoplastic material has been applied to the backing sheet, it is cooled and/or dried into a film by evaporation of the solvents in any desired manner, for example, by the use of heat and/or air, after which it will be found that the thermoplastic film adheres to the backing sheet with sufiicient tenacity for the sheet to be handled incidental to usage, and stored or shipped without rupturing the bond between the backing sheet and the film. The bond so formed is not sufiicient, however, to interfere with the application of the film to'an article to be finished by transferring the film from the sheet to the article. This can be accomplished by the use of relatively low temperatures and relatively low pressures so that the film itself, the backing sheet and the article are not detrimentally affected by the transfer process. The backing sheet may be re-used as many times as desired, depending upon the care which is exercised in preserving the sheet during the transfer operation.

The transfer operation is effected by bringing the article to be finished into contact with the film on the backing sheet and applying heat to the film and/or the article and suffic ent pressure to force the film into contact with and cause it to adhere to the article.

The backing sheet may then be stripped from the film, leaving the same tightly anchored to the article. It is preferable that the film and article be cooled prior to removing the backing sheet since less care is then required in the stripping operation.

The heat and pressure exerted upon the backing sheet, film and article during the transfer process may be supplied by the use of heated platen plates of any well known type, heated calender rolls, steam presses and the like.

By way of illustration and not in limitation of the invention, the following example of the present invention will be given:

A copolymer of vinyl acetate and vinyl chloride was dissolved in acetone to form a 10% solution of the copolymer by weight. A plasticizer sold under the trade name Flexol 3 GH" was added to the extent of 10% of the plasticizer based on the dry weight of the copolymer. The solution so formed was cast by a conventional type of casting machine at room temperature onto a sheet of regenerated cellulose in the form of a sheet of plain Cellophane to form the transfer. The acetone was permitted to evaporate and a film of approximately 0.0002 inch thickness resulted.

The backing sheet bearing the film so formed was placed over a sheet of hard finished paper resting on the lower plate of a press in which the plates were electrically heated to degrees C. The transfer was pressed against the paper under a pressure of 500 pounds per square inch for three seconds. The press was then opened and the transfer and hard finished paper were permitted to cool to room temperature when the backing sheet was stripped from the film which remained tightly adhered to the paper. The paper was thereby provided with a glossy. transparent finish approximately 0.0002 inch thick which adhered to the paper in the presence of mo sture and withstood handling and folding without giving any indication of disengaging from the paper.

The thermoplastic material may have any suitable pigment, filler and/or dyestuff incorporated therein to impart any degree of coloring and/or opacity desired to the film. and may also have moistureproofing agents added thereto, such as waxes, oils. and the like, if desired.

The present process may be used to finish various kinds of fabrics, such as paper, textiles and the like. as well as prints, paintings, photographs. maps, documents, and various articles formed from fibre, cardboard. linoleum. cork and the like.

The finish a plied to such articles by the present process enhances their visual characteristics by increasing their light reflective properties and/or bringing out the details of the print or photograph and, in addition, forms a protective surface which prevents defacement of the article, either intentionally or accidentally either mechanically or by the use of reagents such as acids, alkali and oxidation materials. The transfer films so formed do not shrink excessively when drying since inherently thermoplastic material contains less moisture in the gel stage than nonthermoplastic material. with the result that the backing sheet or the base sheet with the film attached will remain substantially indefinitely without warping or otherwise becoming distorted. Also, the finished article bearing the film so formed may be bent and even folded without fracturing the film or rupturing the bond between the film and the base sheet. Films formed from inherently thermoplastic materials also are capable of expanding and contracting with the base sheet due to changes in atmospheric conditions without cracking or stripping from the sheet. Such films tenaciously adhere to articles to which they are attached, and may be applied to such articles at comparatively low temperatures and pressures, which greatly increases the number of articles which can be so finished. In addition, films formed of such materials do not tend to articles.

de-hydrate and thereby embrittle the sheet as is characteristic of other films.

The films transferred in accordance with the present invention can be made so thin as to be incapable of withstanding handling if unsupported, with the result that thinner and more uniform films can be applied to articles than was heretofore possible. The articles so formed are marked by exceptional stability, striking appearance and a controlled thickness which can be made very small in view of the thinness. It has been found practically impossible to handle films less than about .0006 inch thick heretofore so that films thinner than this could not be applied to Whereas, it is possible by use of the present invention to form and apply films of less than .0001 inch thickness.

The film may be applied continuously over the surface of the base sheet or may be applied in predetermined areas of any desired configuration to enhance or vary the appearance of or change the physical characteristics of any desired portion of the base sheet.

The articles finished in accordance with the present invention may be embossed with any desired indicia and/or configurations on the film side or opposite side or on both sides simultaneously with the application of the films to the base sheets by forming the pressure plates or rollers with raised or depressed portions of any desired shape.

Since certain changes in carrying out the above process, and certain modifications in the article which embody 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.

We claim:

1. A transfer, adapted for use in the coating of a surface with a coating of a synthetic resinous material, which has a backing sheet comprising a smooth, glossy, non-fibrous cellulosic film and a normally non-tacky thermoplastic coating there'- on comprising a synthetic resin temporarily adhered directly to said cellulosic film to provide for handling incident to transfer but having substantially no chemical afllnity to cause permanent adhesion thereto, said coating being releasable to permit transfer of the coating to the surface to be coated upon the contact of said coating therewith and the application of heat to render said coating tacky.

2. The transfer product of claim 1 wherein the smooth, glossy, non-fibrous cellulosic film comprises non-fibrous regenerated cellulose.

3. The transfer product of claim 1 wherein the smooth, glossy, non-fibrous cellulosic film comprises a non-thermoplastic cellulose ester.

4. The transfer product of claim 1 wherein the coating comprises a copolymer of vinyl compounds.

5. The transfer product of claim 1 wherein the coating of synthetic resin is less than .0006 of an inch thick.

CARLE'I'ON S. FRANCIS, JR. WORTH WADE.