US3280732A - Stencil construction - Google Patents

Description

1966 R. MOONEY ETAL 3,280,732

STENCIL CONSTRUCTION Filed Dec. 6, 1960 """WHIIIIIII II! M I 1 VI /3 INVENTORS LA UEENCE .P. Mooms BY LA 022m? 3 Law:

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ATTOEWE'V United States Patent 3,280,732 STENCIL CONSTRUCTION Laurence R. Mooney and Laurence B. Lueck, St. Paul,

Minn., assignors, by mesne assignments, to Elliott Business Machines, Inc., Randolph, Mass., a corporation of Massachusetts Filed Dec. 6, 1960, Ser. No. 75,073 1 Claim. (Cl. 101-1282) The present invention is concerned generally with an improved stencil assembly, and more particularly to an improved stencil assembly which includes, in composite, a master marking sheet, a sheet having a sensitive marking film, and adhesive means for applying the composite arrangement to a working surface.

In stencil work generally, particularly in stencil work wherein a plurality of individual stencil assemblies are stacked in a storage container, normal usage requires that the sheets be uniformly oriented within the container as well as being free one from another. It has been a practice to employ separating sheets which may be utilized between individual stencil assemblies packed together in a single carton enclosure. These separating sheets must be separated out prior to use. For example, in a stencil assembly which is particularly adapted for use in a situation wherein a shipping label, invoices, as well as other billing material may be prepared from a single master stencil, it is desirable to utilize a stencil master which has means for lightly attaching the assembly onto a working surface. In this connection, a pressure sensitive film is deemed most desirable in order to hold the stencil in position while it is being utilized. Of course, the use of a pressure sensitive film on the stencil master makes it extremely difficult to stack the individual items uniformly in a container without employing a separating sheet interposed between individual stencil sheets. In accordance with the present invention, a certain film is applied to .the top or front surface of the stencil which renders that particular surface nonadherent to the pressure sensitive adhesive film. This film and the pressure sensitive adhesive film are mutually incompatible in that they will not adhere, not one to another. In accordance with this feature, it is possible to place the individual stencil assemblies in superimposed stacked relationship without danger of causing these assemblies to adhere, one to another. Inasmuch as various office equipment which is in use today requires that the stencil assemblies be disposed in superimposed stacked relationship, the improved composite assembly of the present invention is particularly adaptable for use in connection with this modern equipment. Since, no mean or spacing sheet is required, the improved stencil assemblies may be placed into the various equipment Without need for pretreatment, removal or separation of a spacing sheet for between individual units.

It is therefore an object of the present invention to prepare composite stencil asemblies which include as a component thereof, a pressure sensitive adhesive film arranged along a first surface portion together with a sec ond film adjacent a second surface portion thereof, the films being arranged in oppositely disposed superimposed relationship along the composite stencil assembly, and being mutually incompatible, one to another.

It is a further object of the present invention to provide an improved stencil composite assembly which includes a pressure sensitive film adjacent a surface portion thereof, the immediate oppositely disposed surface portion of said assembly being treated so as to have a film therealong which holds no afiinity for the pressure sensitive film, thereby permitting the materials to be maintained in superimposed stacked relationship over extended periods of time.

ICC

Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the fol-lowing specification, appended claim and accompanying drawings wherein:

FIG. 1 is a top plan view of the improved composite stencil assembly in the present invention;

FIG. 2 is a vertical sectional view taken along the line and in the direction of the arrows 2--2 of FIG. 1 and showing the arrangement of the various materials and sensitive films, the master stencil member and the copy sheet being shown in reduced scale; and,

FIG. 3 is a vertical sectional view of a composite assembly which is prepared in somewhat modified form from the apparatus shown in FIGS. 1 and 2.

In accordance with the preferred modification of the present invention as illustrated in FIGS. 1 and 2, the stencil assembly generally designated 10 includes a stencil master sheet 11 and a duplicating sheet or carbon sheet 11a superimposed therewith. A backing layer 12 has an adhesive layer 13 on one surface thereof, together with a second layer 14 on the other surface thereof which is provided as a specific repellent for the pressure sensitive film 13. In this connection, the layer 12 is entirely impervious to migration of the sensitive films therethrough, and may, therefore, comprise for example a backing film of polyvinylchloride or the like. The pressure sensitive film 13 may preferably comprise a pressure sensitive adhesive film such as an acrylic copolymer such as ethyl acrylate-methyl methacrylate copolymer, which is heavily loaded with alkaline earth stearates, such as calcium stearate. This film has the characteristic of having an immediate wet-grab, and having a degree of adhesion which does not increase with time. Accordingly, the stencil sheet assembly may be attached and removed with ease, the adhesive film being releasably secured to an adjacent layer or film onto which the adhesive has been holding the composite label assembly. The layer 14 is likewise preferably selected from the group of materials known as polymeric alkyl siloxanes. Accordingly, these composite stencil assemblies may be packaged in superimposed relationship without requiring a separating or spacing layer to be interposed between individual elements.

According to a modified embodiment of the present invention as shown in FIGS. 1 and 3, the stencil assembly 10 includes, in composite, a master stencil sheet 11 and a tracing or copy sheet 11a. Copy sheet 11a is again conventional, is impregnated with a material such as carbon or the like for making a permanent impression or indicia on the surface of the sheet to which the stencil assembly has been initially tabbed. It may be pointed out at this time that the present invention is an improvement over the stencil assembly disclosed and claimed in US. Pat. No. 2,771,026, Laurence R. Mooney, which patent is assigned to the same assignee as the present invention. The master stencil sheet adjacent the copy sheet is treated as is conventional, in the art, this being a highly porous paper base which has been plastic coated so as to allow the body of the coating to separate upon being pressed or struck with a relatively sharp object, such as an indicia producing object. The copy sheet may be carbon paper, Kozutint lace type tissue having a carbon coating or the like, the copy paper likewise being conventionally used in the art. Both the stencil master paper and the copy paper are commercially available.

A member 22 having an adhesive film 27 along one surface is placed in superimposed relationship over the main or master stencil sheet 11 and the copy sheet 11a in order to retain the pair in properly arranged superimposed composite relationship, one to the other and to hold the assembly in working contact with a surface to be treated.

' crease with time.

The backing paper 24 is attached or secured to the backing film 26 through the pressure sensitive adhesive layer 25, this layer being preferably an acrylic copolymer such as ethyl acrylate-methyl methacrylate. Such pressure sensitive adhesive materials are commercially available and widely employed in the adhesive art today. Layer 23 is a silicone film arranged along the surface of the backing 24. The backing film 26 which may be, for example, a polyvinyl-chloride film is provided with a second adhesive layer 27 which is likewise pressure sensitive and which is provided to retain the stencil member 11 and a copy member 11a in mutually predetermined relationship, and further to provide an adhesive area or surface which is available to hold the composite assembly on a surface such as a carton surface, an invoice label surface or the like. The backing material 26, as indicated, comprises polyvinyl-chloride, but may also be comprised of any material which is impervious to migration of the adhesive layers 25 and 27 thereacross, these layers being, in certain instances, of different characteristics. Accordingly, thecomposite assembly of the present invention does not significantly age during storage and the shelf life is therefore reasonably long. Adhesive layer 27 is one which has an immediate wet-grab and one which has a degree of adhesion which does not in- It is therefore possible to apply, remove and reapply these stencil assemblies to a plurality of different work surfaces. Such an adhesive may be an acrylic copolymer such as ethyl acrylate-methyl methacrylate coploymer (55-45 EAMM) having a molecular weight which is relatively low for acrylic adhesives and which has been heavily doped with an alkaline-earth stearate;

In accordance with the embodiments of the present invention, the composite stencil assemblies may be arranged in superimposed relationship and packed in a conventional fashion without danger of adherence between the individual assemblies or units. The silicone layers 14 and 23 respectively are substantially noncompatible with the pressure sensitive adhesive layers 13 and 27 respectively, and accordingly there is no tendency for the individual assemblies to stick, one to the other. This makes it possible to superimpose the assemblies in stacked relationship for use in accordance with the requirements of modern duplicating equipment, without requiring the operator to remove a spacing or separating layer between individual assemblies.

A suitable silicone material for use in connection with the present invention has been found to be a certain alkyl polysiloxane sold by Dow-Corning Co., Midland,

Michigan, and identified by their code-name DC. No. 23. A second suitable material is their similar siloxane identified by the code-name DC. 22 both of which are believed'to be predominantly 'di-methyl siloxanes.

For purposes of convenience of fabrication, layer 25 has been disclosed as being pressure sensitive. It will be appreciated, however, that other types of adhesives 4 may be satisfactorily utilized in place of the pressure sen sitive type, such as either heat activated or solvent acti vated adhesives.

It will be appreciated that the specific examples give] herein are provided for purposes of illustration only an are not to be construed as a limitation upon the scope 0 coverage to which this invention is reasonably entitled What is claimed is:

In a stencil assembly comprising a relatively narrov securing strip having a pressure-sensitive adhesive coat ing of a type to permit the same to be removably adhere'c to another sheet, a stencil sheet afiixed on one side along one marginal edge portion to only a portion of sait adhesively coated strip, disposed in juxtaposition to the other side of said stencil sheet a separate carbon shee afiixed along one marginal edge portion to only a par of the remaining exposed adhesive coating on the bottorr side of said strip to leave a portion of the underlying adhesive coating expose-d for removable attachment tc a selected part of a larger sheet, the improvement wherein said securing strip consists of a backing paper coated on one side with an alkyl polysiloxane which is substantially mutually incompatible with said adhesive coating the other side of said backing'paper being fixedly secured by a copolymer of ethylacrylate and methyl methacrylate to one side of a backing film of polyvinyl chloride, and the other side of said backing film being coated with the pressure-sensitive adhesive having an intermediate wetgrab, said adhesive being a relatively low molecular weight copolymer of ethylacrylate and methyl methacrylate which is heavily doped with an alkaline earth stearate.

References Cited by the Examiner UNITED STATES PATENTS 1,954,805 4/1934 Drew 101127 2,439,481 4/1948 Martin 1l7-68.5 2,484,416 10/1949 Martin 11768.5 2,496,349 2/1950 Kellgren et al. 117-122 2,525,864 10/1950 Carter 117-122 2,532,011 11/ 1950 Dahlquist et a1. 117122 2,544,315 3/1951 Heldmann 117-122 2,588,367 3/1952 Dennett 1l7122 2,599,576 6/1952 Morris et al 117-68.5 2,771,026 ll/l956 Mooney 101128.2 2,803,613 8/1957 Kather et a1. 117-122 2,822,290 2/ 1958 Webber 117122 2,956,904 10/ 1960 Hendricks 117122 2,971,863 2/1961 Kindseth et al. 11768.5 3,050,411 8/1962 Keil ll768.5 3,050,425 8/1962 Carr et al 156-332 X DAVID KLEIN, Primary Examiner.

R. LEIGHEY, ROBERT E. PULFREY, Examiners.

E. T. WRIGHT, Assistant Examiner.

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