US2123180A - Sheet material - Google Patents

Description

E. A. CORBIN, JR., ET A1. 2,123,180

July 12, 1938.

SHEET MATERIAL Filed NOV. 20, 1934 im@ N@ SNN @@@rnw Wao Patented July 12,- 1938 PATENT OFFICE SHEET MATERIAL Elbert A. col-bin, Jr., Gradyvme, and auwooa w. Wolf, Philadelphia, Pa., assignors of one-third to William C. Biddle, Lansdowne, Pa.

Application November 20, 1934, Serial No. 753,812

1 Claim.

Our invention relates to a new and useful sheet material and method of making the same whereby a thin, transparent or-translucent, water-proof sheet material is used. of the type now generally (ised for wrapping goods on display counters hermetically to seal the goods and at the same time to display the same to the best advantage.

.j There is at present available on the market thin, transparent sheet material known as cellophane" which is generally a glycerinated sheet of regenerated cellulose which is extensively used for wrapping all kinds of merchandise, such as candles, cigars, cigarette packages, shirts, stockings. handkerchiefs, etc., this sheet material being however only water repellent or resistant, but not watebproof, and being relatively experidive'due to the cost involved in the complicated l chemical manufacturing steps by which this sheet l rhV al is produced. Furthermore, the sheet m al referred to is of a limited toughness and flexibility. j It is the object of our invention to produce a sheet material of this character which is waterproof and which possesses great toughness and resiliency andwhich can be made at much less y cost than sheet material of this type now available.

Our invention also relates to the novel method of manufacturing our novel sheet material by means of a continuous process utilizing ready made', relatively inexpensive ingredients, thus obviating the necessity of expensive and complicated chemical processes. l

The accompanying drawing is a diagrammatic representation of the form of machine by means of which our novel continuous process of making the sheet material formingl the subject of 'our in# vention may be carried out.

Our novel transparent sheet material is formed of a body substance, a glossing substance, and a water-proofing, resilient and strengthening-substance' either intermingled in the original compositionor applied together successively to form ',lahilnations of thin lms of the substances used in any desired order. In actual practice we have fcundthat liquid `latex or-a similar compound may be used to add strength and resiliency to the finished sheet material as well as thoroughly and positively to water-proof the finished product. We als found that a gelatine or ,similar com l)Sound is an inexpensive, convenient and practical body substance which can be utilized to give the sheet material the desired thickness-and we also found that shellac or a similar drying Il glossy compound can practically and conveniently be used to give the outer surface ofthe sheet material the desired finished and lustrous appearance. In carrying out our invention we preferably utilize a continuous belt, one face or surface of which is made to dip into or pass through a series or succession of vats containing the diiferent ingredients of which the sheet material is to be made, properly arranged, whereby a film is formed on said belt, which film when stripped of thebelt constitutes a sheet material of our invention. n f

In order more clearly to illustrate our invention, we refer to the accompanying drawing in which I designates a continuous belt which passes through an aperture 2 in the working platform or floor 3 of the room and under the roll 4, over one or more rolls 5, under the roll E, over the roll 1, underthe roll B, over the roll 9, and under the drum I0. Under and registering with the drum I0 is a tub I2 adjustably mounted on the leg Il and containing one of the materials used in forming the sheet material of our invention in a liquid form, which in this instance is shellac I5. The outer'surface I6 of the belt I is then coated with a nlm of shellac, the thickness of which can be predetermined by the nature of the surface IB of the belt I, the viscosity of the liquid I5, as well as the rate of travel of the belt during its contact with the liquid I5. The illm thus `formed on the surface I6 of the belt I is so thin as not to per-v mit illustration in the drawing, since the finished product is perhaps less than one-thousandth of an inch thick. The belt I then enters the heating chamber or oven I8 through the aperture I9 and passes alternately over and under the rollers 20 and 2 I, respectively, and emerges from the chamberV I8 through the aperture 22. The chamber ldlmay be heated by means of the heating elements 23 or the rollers 2|) and 2I may themselves be made hollow and supplied with steam, hot air or other heating medium. In the heating cham` ber I8 the film of shellac applied to the surface I6 of the belt I is dried by the heat from the chamber I8 and is calendered by its passage over and under the rolls 20 and 2i. The belt I then passes over the guide roll 2li, under the guide rolls 25, over the guide rolls 26, and under the next adjacent drum 21, to come in contact with the liquid 28 in the vat or tub 29, which liquid in this instance is preferablyV a solution of gelatine calculated to give body to the sheet material to be formed. After being coated with a lm of a gelatinous solution the belt enters the heating chamber 3U which is also supplied with the rollers 2li and 2| and which is similarly heated, so that when the film of gclatlnous solution deposited on the belt is dried and calendered the belt emerges from the chamber 8l and goes over and under similar rolls 2l, II and Il to pass under the drum 3l and come into contact with the liquid Il in the vat ll, which in this-instance is liquid latex or other solution of rubber or waterproofing substance, whereupon the belt enters the heating chamber It where this film bi waterproofing material is also calendered and dried over the-films of gelatinous and lustrous substances already deposited' on the belt during its passage through the vats I2 and 2l. In order to make a balanced sheet, that is one ot a symmetrical construction so as to` prevent curling and warping of the sheet in` manipulation and use, we deposit a second film of gelatinous substance 28 in a second vat 2l, and a second nim of shellac or lustrous substance it in a second vat i2. it being understood that the added aims of gelatinous and shellac substances are also dried and calendered in the heating chambers Il and ll'which are also provided with the rolls 20 and 2| in the same manner as the heating chambers Il and 3l. When the belt finally emerges from the heating chamber 3l through the outlet opening It, the sheet material Il composed of the central rubber or waterproofing solution Il, the films of gelatinous or bodyl substance 2l on either side thereof and the outer films of shellac or other lustrous substance Il is peeled of! the belt and rolled on .a take-up roll (notshown). 'I'he belt I may be continuously driven by means of the drums I ll, 21 and il which are propelled by any suitable means (not shown), or separate driving rolls (not shown) may be employedat either or both ends of the apparatus to propel the belt, if so desired.

While we have found in practice that five "dippings, as shown, namely: the two outer shellac layers, the two intermediate gelatine the central rubber or other waterproofing layer, are suflicient to produce the sheet material of our invention, and while it is within the scope of our invention to vary the thickness of the sheet material produced by regulating speed of travel oi' the belt, by changing the surface tension properties of the face of the belt, or by regulating the viscosity of the various liquid ingredients used. it is to be understood that it is also within the scope of our invention to use any number of vats and subject the belt to any desired number of "dippings so as to produce a thicker or thinner sheet at will.

Also, while we have shown our invention as consisting in placing on the belt I successive layers or lms of lustrous, gelatlnous and rubber solutions, it is within the scope of our invention to mix the rubber or water-proofing substance with the gelatinous or body forming substance in the same vat to form a single film of the desired thickness, which film is provided with outer surface coatings of any lustrous substance to give it thehecessary finish.

v either side of the central rubber layers, and

While we have found in practice that shellac 'gives the 'proper luster, that gelatine forms a lood body ingredient, and that liquid rubber forms an adequatewater-proonng element, it is to be understood that other ingredients which have waterfprooiing qualities, which would constitute flexible and transparent body substances. and which would give the product the necessary finish, can be used ywithout departing .from the spirit or scope oi' our invention.

It is to be understood that it it is desired to produce a colored sheet material according to bur invention it is merely necessary to introduce 'a dye or combination of dyes into one or more of thevsubstances of which the finished product is formed, thus producing a sheet material having -a's it is turned out and by replenishing the cons' tents ofthe vats I2, 29 and 35. In carryingaut our process we found it advisable to separate the various heating chambers Il, l0, It, il and Baby suitable partitions 42 in order to enable us toy regulate the drying capacityv of each. heating chamber in accordance with the requirementyof the particular substance the film of which is to, be dried in the particular chamber. c,

Tne -gelatinous films or coatings employedv on. film. or coating in addition to giving the finished sheet the necessary body also provide a surface having the neces-- sary tension or cohesion to insure theunii'orm spreading and adhesion of the rubber nlm. l

By utilizing the central rubber film with the, outer sheliac films and the intermediate gelati-, nous films or their equivalents we produce ,-al balanced sheet, that is, one having a, svinmetrical cross section, thereby insuring that, the. sheet will remain fiat in use and eliminating the possibility of the sheet curling or warping. It will be seen that our novel product lcan be, made at a very low price, due tothe veryiow cost of the ingredients utilised,y and that the continuf, ous process ofI forming the sheet material and, taking it ofi' from the belt permits oi constant operation and greatly reduces the cost of manu-i, facture asl compared with the manui'actlireosi-14 other synthetic sheets heretofore known I which are produced by the extrusion process. which inf-,f volves the use 'of very exact and expensive ma, chinery, if a thin, uniform product iste be made. We claim: i y A composite wrapping sheet material compris-i in integrated form, a central layer ,formed of a rubber compound, outer layers formed cfa water-prooiing resinous substance, and layers-of an adhesive gelatinous substance intermediate and inter-connecting the opposite-.sides oLsaid. central layer with said outer layers.

ELBERT A. CORBIN, Jn. ELLWOOD W. WOLF.

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