US3343978A

US3343978A - Adhesive transfers

Info

Publication number: US3343978A
Application number: US339062A
Authority: US
Inventors: Thomas J Engelbach
Original assignee: Avery Products Corp
Current assignee: Avery Products Corp
Priority date: 1964-01-09
Filing date: 1964-01-09
Publication date: 1967-09-26
Anticipated expiration: 1984-09-26

Description

Sept 26, 1967 T, J. EN'GELBACH 3,343,978

ADHESIVE TRANSFERS Filed Jan. 9, 1964 2 Sheets-Sheet-2 INVENTOK F/o Mns J CA/@EL @Ac/f BY MW United States Patent O 3,343,978 ADHESIVE TRANSFERS Thomas I. Engelbach, Middletown, NJ., assignor to Avery Products Corporation, San Marino, Calif., a corporation of California Filed Jan. 9, 1964, Ser. No. 339,062 7 Claims. (Cl. 117-76) This application is a continuation-in-part of the copendiug application of Thomas I. Engelbach, S.N. 99,244, iiled Mar. 29, 1961, now abandoned.

This invention relates to adhesive transfers and more particularly, to adhesive transfers, processes for producing them, and methods of applying them to other surfaces.

An object of this invention is to transfer a pressuresensitive adhesive to a body so that the face surface thereof after transfer is adapted to adhere to another body upon the application of pressure to join together firmly the two bodies.

Another object of this invention is to afliX an adhesive to a portion of an article by the application of heat or solvent whereby other surfaces may be bound to the article at such portion.

Another object of this invention is to bind two surfaces of different materials for which a common adhesive material is not available.

A further object of this invention is to provide a label which can be sealed to a package and can be pulled free to expose a tacky surface which can be employed to reseal the package.

An example of the need of an efficient, economical jointure is illustrated by the so-called bumper label. The customary procedure for manufacturing these labels is for a job printer to purchase blank strips of paper having at the two ends thereof tacky adhesives completely covered with a release paper. He then prints the desired message or design on the strip. The bumper strip is adhered to the automobile bumper by removing the release paper and applying pressure to the bumper strip.

Currently used bumper strips frequently are covered only on portions of the obverse side and such strips, because of the non-uniformity of surface, are diliicult to print. In addition, the printer cannot use his usual stock of paper for bumper labels but must procure special and more costly adhesive bearing blanks for this purpose.

In accordance with one aspect of this invention, an adhesive transfer is provided which can be applied to a label printed on any stock paper. The printer may proceed with the printing of the label in the same manner as he would for any other type of printing and then apply the adhesive transfer of this invention to the entire back or any desired portions of the back, such as the ends of the label.

In accordance with another aspect of this invention, an adhesive transfer is provided which has a label eX- posed on a surface opposite that containing an adhesive. The adhesive surface opposite that containing the label may be activated by heat or solvent and after activation the transfer may be applied as a closure to a package. The label can be pulled free exposing a tacky pressure sensitive adhesive attached directly to the label sheet and capable of adhering to reseal the package. The adhesive transfer in accordance with this aspect of the invention enables the closure of a package and its opening and resealing at any predetermined intervals.

The adhesive structures of this invention comprise a flexible substrate, a pressure sensitive adhesive in contact with the substrate, and a non-tacky layer adhering to the surface of the pressure sensitive adhesive. The non-tacky layer may be heat activated, solvent activated or both and is convertible to a tacky adhesive surface by the ap- 3,343,978 Patented Sept. 26, 1967 ICC plication of heat or solvent. When the pressure sensitive adhesive has greater cohesion than its adhesion to the substrate, the non-tacky layer of the adhesive structure when activated has at least 10% greater adhesiveness to the pressure sensitive adhesive than its cohesion. When the pressure sensitive adhesive has greater adhesion to the substrate than its cohesion, the non-tacky layer when activated has at least 10% greater cohesion than its adhesion to the pressure sensitive adhesive.

In the first aspect of this invention, the pressure sensitive adhesive of the adhesive structures of this invention has greater cohesion than its adhesion to the substrate and the non-tacky layer of the adhesive structure when activated has at least 10% greater adhesiveness to the pressure sensitive adhesive than its cohesion. The adhesive structures or transfers in accordance with the first aspect of this invention are particularly applicable to bumper labels and many and varied other situations when the pressure sensitive adhesive has greater cohesion than its adhesion to the substrate. Desirably, the characteristics of the substrate in this first aspect of applicants invention preferably has low adhesion to the pressure sensitive adhesive. The adhesive structure in accordance with the first aspect of this invention is transferred to a surface by converting the non-tacky layer to a tacky surface by the application of heat in the case of a heat activated non-tacky layer or by the application of solvent in the case of a solvent activated non-tacky layer and applying the resulting coated tacky layer to the surface upon which the transfer is to be made. Pressure is then applied to the substrate to form a bond between the adhesive structure and the surface. The substrate is then removed to expose the pressure sensitive adhesive for attachment to another surface whereby a jointure is effected between the two surfaces.

In the second aspect of this invention, the pressure sensitive adhesive of the adhesive structure has greater adhesion to the substrate than its cohesion and the nontacky layer when activated has at least 10% greater cohesion than its adhesion to the pressure sensitive adhesive. The adhesive structure in accordance with the second aspect of the invention may beA utilized as a means of closing packages. In this aspect of the invention, the non-tacky layer is activated by heat or solvent and the activated lsurface is applied to the portion of the package 'to be closed. The substrate which comprises the opposite surface to that of the heat or solvent activated surface may have printing or advertising `or other designation thereon. If desired at any time after closure, the seal may be removed by grasping an end of the substrate. When the end of the substrate is elevated above the previously sealed part of the package, it carries with it the pressure sensitive adhesive because the pressure sensitive adhesive has greater adhesiveness to the substrate than its cohesion. The activated non-tacky layer remains on the -package wrappings because when so activated it has 10% greater cohesion than its adhesion to the pressure sensitive adhesive. When t-he end of the substrate is elevated above the previously sealed part of the package, therefore, a relatively clear cut break occurs between the pressure sensitive adhesive and the activated non-tacky layer. When it is desired to reseal the substrate to the Wrappings, the tacky surface of the pressure sensitive adhesive on the substrate is contacted with the tacky surface of the activated non-tacky layer on the wrappings and the substrate and contacting wrappings are quickly rejoined by the application of pressure to form a com-plete closure member. This breaking away and resealing may be repeated substantially indefinitely as desired. This adhesive structure of this invention is particularly adapted to the sealing of cellophane or Saran Wrapping of bread or similar food products. At the end of each cellophane or saran wrapped loaf of bread, for example, the cellophane or saran wrapping may be folded and the adhesive struct-ure attached thereto by the activation of the non-tacky layer. Printing or other advertising designations may be imprinted on the substrate prior to activation of the adhesive transfer. After activation of the non-tacky layer by solvent or heat, the label seal may be ixedly attached to the folded portion of the bread wrapper. If desired, at any time thereafter, the substrate of the adhesive )transfer may be easily removed by simply lifting the substrate away from the package. When so removed, the pressure sensitive adhesive is retained on the substrate and the activated non-tacky layer is retained on the package. The pressure sensitive adhesive on the substrate and the activated nontacky layer on the package insure a quick and effective seal when closure of the package of bread is again desired.

The non-tacky adhesive layer may be heat activated or solvent activated, or both, and is of a type such that the activation results in the conversion of the non-tacky adhesive into a tacky body having at least greater adhesiveness to the pressure sensitive adhesive than its cohesion or at least 10% greater cohesion than its adhesion to the pressure sensitive adhesive depending upon the particular adhesive structure desired.

The non-tacky adhesive layer may be coated directly on Ito the pressure sensitive adhesive. Alternatively, it may lbe a strip or sheet of material, such as cellophane, adjacent the pressure sensitive adhesive.` When the non-tacky layer has at least 10% greater adhesiveness to the pressure sensitive adhesive than its cohesion, the pressure sensitive adhesive has greater cohesion than its adhesion to the substrate. On the other hand, when the non-tacky layer has at least 10% greater cohesion than its adhesion to the pressure sensitive adhesive, the pressure sensitive adhesive has greater adhesion to the substrate than its cohesion.

The substrate which may be of fibrous or non-fibrous structure or both is a exible membrane. Examples of such a substrate are paper, plastic films, textiles, Holland cloth or cellophane.

In the production of the adhesive structure in which the pressure sensitive adhesive has greater cohesion than adhesion to the substrate, the substrate is desirably a flexible material which may be fibrous or non-fibrous or a combination of both. Examples of a substrate for this purpose are: paper, plastic films, textiles, Holland cloth, cellophane or any other flexible material which by its characteristic or treatment has a lower adhesion for the pressurel sensitive adhesive.

For the production of an adhesive structure in Which the pressure sensitive adhesive has greater cohesion than adhesion to the substrate and in which the non-tacky layer has at least 10% greater adhesion to the pressure sensitive adhesive than its cohesion, the non-tacky layer may be solvent activated or heat activated or both and in addition may be thermosetting. The pressure sensitive adhesives may be reinforced with fiberglass or similar substances such as nylon lilament. Examples of adhesives employed in this aspect of the invention are: hot melt adhesives, lacquers (solvent solution), dispersions (resin ground in water) and emulsions of resins. For example, certain thermoplastic materials, such as polyvinyl acetate, may be simply melted and applied (hot melt). Alternatively, the polyvinyl acetate may be dissolved in a solvent such as tol-nene and applied as one of the adhesives. Again, the polyvinyl acetate may be dispersed in -water by simply initially grinding 'the polyvinyl acetate -to fine particle size and agitating it` Finally, the polyvinyl acetate may be emulsied by any of the Well known procedures and the emulsion applied to obtain the desired coating. The thermosetting resins may be utilized in the form of a lacquer or solution or in the form of an emulsion to obtain the adhesive transfer and the curing may be effected after the transfer has been applied to the surfaces to be joined. A -solvent activated adhesive may be hot melted or applied in the form 0f an emulsion to obtain the adhesive transfer. The solvent is then removed by evaporation and the transfer later activated by a solvent when it is applied to the surface to be joined. If the solvent activated adhesive is also thermosetting, the curing is effected after the adhesive transfer is applied to the surfaces 'to be joined.

In the production of an adhesive structure in which the pressure sensitive adhesive has greater adhesion than cohesion to the substrate and in which the non-tacky layer has at least 10% greater cohesion than its adhesion to the pressure sensitive adhesive, the non-tacky layer may be a coating or film, the properties of which depend on the type of surface to which it must adhere. For example, the non-tacky layer may comprise cellophane as a carrier with a release coating on one side (in contact with the pressure sensitive adhesive) and a nitro cellulose or saran layer on the other side, depending upon the surface to which it is to be bonded. Examples of surfaces are: nitrocellulose coated cellophane, saran coated cellophane, polyethylene, oriented polypropylene and paper. Polyethylene or polypropylene may be used as a carrier. If the nontacky layer is a coating, it may be for example, polyvinylidene chloride copolymer resin, of vinylidene chloride copolymerized with about 5% of methylacrylate, itaconic acid or acryonitrile. One such composition is sold under the tradename of Dewey & Almys Daran 210. The substrate is desirably flexible and has greater internal strength than the adhesiveness of the pressure sensitive adhesive. If used as a label, it would allow the label to be peeled back without tearing. Examples of label stock papers which may be used for this purpose are: cast coated printing stock, litho label stock, olf-set label stock and machine finished label stock.

The pressure sensitive adhesive may be any pressure sensitive adhesive which has greater adhesiveness to the substrate than its cohesion. Examples of pressure sensitive adhesives are those later described and designated as formulations 2 and 3.

A more comprehensive understanding of this invention is obtained by reference to the accompanying drawing in which:

FIG. 1 is a perspective view partly broken away, of an adhesive structure of this invention;

FIG. 2 is a side elevation of an adhesive shown in FIG. 1 and illustrates the manner of removing the substrate from an adhesive of the type of adhesive structure in which the pressure sensitive adhesive thereof has greater cohesion than its adhesion to the substrate and in which the non-tacky layer thereof when activated has at least 10% greater adhesiveness to the pressure sensitive adhesive than its cohesion;

FIG. 2A is an adhesive structure shown in FIG. 1 and illustrates the manner of removing a label from an adhesive of the type of adhesive structure in which the pressure sensitive adhesive thereof has greater adhesion to the substrate than its cohesion and in which the nontacky layer thereof when activated has at least 10% lgreater cohesion than its adhesion to the pressure sensitive adhesive;

FIGS. 3 and 4 illustrate processes for the production of the adhesive transfers of this invention;

FIGS. 5 and 6 show methods of laminating the adhesive transfer of this invention in a continuous manner to webs of flexible materials.

In FIGS. 1 and 2, the adhesive structure comprises a substrate 10, having a tacky pressure sensitive adhesive 11 in contact with a surface of the substrate. Intimately bound with and covering the pressure sensitive adhesive 11 is a layer 12 which is normally non-tacky and may be a film or coating on the surface of the pressure sensitive adhesive. The non-tacky layer 12 is capable of being activated by heat or by a solvent to produce a tacky body.

The physical structure of the adhesive structure and the special relationship of the substrate, pressure adhesive and non-tacky layer is the same whether the pressure sensitive adhesive has greater or less adhesion to the substrate than its cohesion. If the pressure sensitive adhesive has less adhesion to the substrate than its cohesion, the non-tacky layer of the adhesive structure has at least greater adhesiveness to the pressure sensitive than its cohesion. On the other hand, if the pressure sensitive adhesive has greater adhesion to the substrate than its cohesion, the non-tacky layer has at least 10% greater cohesion than its adhesiveness to the pressure sensitive adhesive. Although the two different adhesive structures have significantly different characteristics, they may be manufactured by the same techniques, as presently described, with the appropriate selection of types of the three components, substrate, pressure adhesive and nontacky layer, to produce the particular kind of adhesive structure desired.

An example of a non-tacky layer is a combination of neoprene and a phenol formaldehyde resin in a solvent such as toluene, xylene or acetone. Based on 100 parts of neoprene, there is mixed between 10 and 50 parts by weight of phenol formaldehyde resin. Sufficient solvent is added to permit easy distribution of the combination on the first adhesive. Alternatively, a straight resin such as urea formaldehyde dissolved in a solvent may be employed. Neoprene formulations are either solvent activated or heat activated. If solvent activated, a solvent such as toluene is simply smeared or sprayed over the second adhesive, resulting in the formation of a tacky mass.

The application of the adhesive transfers of this invention is illustrated in FIGS. 2 and 2A. The second adhesive of the transfer is first activated by a solvent or by heat, depending upon its characteristics. For example, in the case of a neoprene type of solvent activated nontacky adhesive, a solvent such as benzene is smeared or sprayed over the neoprene adhesive and it becomes tacky. The tacky facing of the activated previously non-tacky adhesive 12 is then applied to the surface of an article 13 to be joined with the surface of another article. Pressure is applied through the substrate 10, as indicated by the arrows, to insure binding of the adhesive transfer to the surface of the article 13. The substrate 10 is then removed, exposing the tacky surface of the first adhesive 11. That tacky surface then contacts the surface of the second article to be joined. Pressure is applied to effect good adhesion between the article 13 and the other article to be joined to it.

FIGS. 3 and 4 show two methods for producing the adhesive transfers of this invention. In FIG. 3 a roll coating apparatus is employed, while in FIG. 4 roll and snray equipment is used.

In FIG. 3 a backing web or substrate 30 in the form of a coil 31 is unwound in the direction of the arrow and passes over a roller 32, under a coating head comprising two

rollers

33 and 34 and a reservoir 35 containing the first or pressure sensitive adhesive. The web with the first adhesive thereon is then passed through a drier 36 as indicated by the direction of the arrow. After drying of the first adhesive, the coated web passes over a roller 42, under a second coating head comprising the

rollers

37 and 38 and reservoir 39 containing the second or non-tacky adhesive. It is then dried by passage through an oven 40. The coated web with the rst and second adhesives thereon is then wound up in the form of a coil 41.

In FIG. 4 the first or pressure sensitive adhesive is coated on a web in the same manner as that illustrated in the apparatus shown in FIG. 3. The uncoated web 44 in the form of a coil 45 passes over a roller 46 and under a coating head comprising a reservoir 47 containing the first adhesive and two

rollers

53 and 54. The coated web 44 then passes through a drier 48, after which a spray coating device 49 containing the second or non-tacky adhesive effects the coating of the second adhesive over the 6 first adhesive on the web. The coated web then passes through a drier 50, over a roller 51, and the completely coated web is then collected in the form of a coil 52.

In the practice of producing the adhesive transfers of this invention with the apparatus shown in FIGS. 3 and 4, the solvent for the second adhesive desirably may be for the same purposes capable of swelling the first adhesive. In this way the first adhesive becomes intimately bound to the second adhesive.

FIG. 5 shows the method of laminating an adhesive transfer of FIG. 2 of this invention to a web of flexible material. A roll .60 of an adhesive transfer 61 of this invention, the exposed or second adhesive of which is normally non-tacky but capable of being activated by heat, passes over

guide rollers

62 and 63 to a heat lamination station comprising heated rollers 64 and 65. The rollers 64 and 65 may be heated by any convenient means such as by electricity or steam to maintain the rollers at a temperature sufficiently high rto activate the exposed or second adhesive of the adhesive transfer 61. At the heat lamination station, the adhesive transfer is contacted with a flexible web 66 which is supplied by a supply roller 67 passing over a guide roller 68. The heated rollers 64 and 65 rotate at a sufficient speed and exert sufficient pressure on the web 66 and adhesive transfer 61 to effect good adhesion between the transfer and the web. The resulting lamination passes over a guide roller 69 to be wound in the form of a roll 70.

FIG. 6 illustrates the method of laminating a web of an adhesive transfer of FIG. 2 of this invention in which the exposed or second adhesive is solvent activated. In FIG. 6, a roll 73 of an adhesive transfer 74 of this invention in which the second or exposed adhesive is normally non-tacky but capable of being activated by the application of solvent thereto, passes over guide rollers 75and 76 to a solvent spray 77. The application of the -solvent on the exposed or second adhesive activates it. In the activated state, the second adhesive contacts a web of exible material 78 which is supplied from a roll 79 of the material after passage over a guide roller 80. The web 78 and the activated second adhesive of the transfer 74 contact each other as they pass between the two

pressure rollers

81 and 82. The pressure exerted between the

rollers

81 and 82 and the speed of the passage of the web and transfer are such that good adhesion is effected between the web and transfer. The resulting lamination of web and transfer passes over a guide roller S3 to be wound in the form of a roll 84. The laminating methods illustrated by the apparatus of FIGS. 5 and 6 may also be employed for producing laminated structures as shown in FIG. 2A. Examples of formulations which may be used as the adhesives of this invention are:

FORMULATION 1 Prelrsure sensitive adhesive with natural rubber las the base material Parts by weightV Milled smoke sheet rubber Polyterpene resin with a softening point of about 100 C. (Piccolyte 100 manufactured by Pennsylvania Industrial Chemical Corporation is a polyter- FORMULATION 3 Pressm-e sensitive adhesive with polyzlroburylene as the base material Parts by weight Polyisobutylene having a molecular weight within the range of 85-100,000 100 Polybutylene having a molecular weight within the range of 10-l2,000 Polyterpene resin having a softening point of 100 C. (Piccolyte 100 is satisfactory 'for this purpose.) 12.5 Toluene 325 FORMULATION 4 Pressure sensitive thermosettng adhesive Parts by weight Milled smoke sheet rubber 100 Polyterpene resin with softening point of about 100 C. (Piccolyte 100 is satisfactory for this purpose.) 125 Heat reactive phenolforrnaldehyde resin such as bakelite No. 10,282 which is manufactured by the Bakelite Division of -Union Carbide and Carbon Company 65 An antioxidant such as di--naphthyl-para-phenyldieneiamine 3 Toluene 600 FORMULATION 5 Heat activated adhesive Parts by weight Polyethylene having a molecular weight of Aabout Parts by weight Polyamid resin (Versamid 94, manufactured by General Mills Corporation is satisfactory for this purpose.) Hydroabietyl alcohol (The hydroabietyl alcohol manufactured by Hercules Powder Co. and sold under the name Abitol is satisfactory for this purpose.) 7 Polyterpene resin with a softening Apoint of about 100 C. (Piccolyte 100 may be used.) 20 Antiblock agent, s-uch as C-arnauba wax 10 FORMULATION 7 Solvent activated thermosetting adhesive Parts by weight Rapid crystallizing chloroprene polymer (Neoprene AC is satisfactory for this purpose.) 100 Zinc oxide 10 Heat reacting phenylformaldehy-de resin such as BAKELITE 10,282 manufactured by the Bakelite Div. of Union Carbide & Carbon Co. 30 An antioxidant such as phenyl--naphthylamine 3 Toluene i 300 t3 FoRMULATioN s Solvent activated adhesive which may be used as a norttacky coating Parts by Weight An ethylene vinyl acetate copolymer having a softening point of 243 F. (R & B) sold under trade name of Elvox 150 and manufactured by the E. I.

du Pont Co. 40 Paran having a melting point of 135 C 40 Polyterpene resin with a melting point of C.

(Piccolyte 100 manufactured by Pennsylvania Industrial Chemical Corporation is a polyterpene which is satisfactory for this purpose.) -20 Formulations l through 4 are suitable as the first adhesive, while Formulations 5 and 6 are adapted for use as the second adhesive. Formulation 7 may be used as a rst or second adhesive.

The specific embodiments of the invention disclosed herein are not to be construed as limitations but as illustrations of the invention. Various changes and modifications may be made in carrying out this invention without departing from the spirit and scope thereof.

A pressure sensitive adhesive is meant whenever the term first adhesive is stated herein and a non-tacky solvent or heat activated adhesive is meant whenever the term second adhesive is stated herein.

What is claimed is:

1. An adhesive structure comprising a flexible substrate layer, a non-tacky layer7 a pressure-sensitive adhesive having 'a first side in adhering contact with said substrate layer and a second side opposite said first side in Iadhering Contact with said non-tacky layer, said non-tacky layer being convertible to a layer having a tacky adhesive surface on its side opposite said pressure-sensitive adhesive, the adhesion at one of said surfaces of said pressuresensitive adhesive between said pressure-sensitive adhesive and the adjacent one of said layers being less than the ad- Ihesion at the other of said surfaces of said pressuresensitive adhesive between said pressure-sensitive adhesive and the other one of said layers, said pressure-sensitive adhesive separating along said one surface thereof from the adjacent -layer land remaining with said other adjacent layer when said layers are pulled apart.

2. An adhesive structure as set forth in claim 1 wherein said non-tacky layer is a heat activated layer which is convertible to supply said tacky adhesive surface by the application of heat.

3. An adhesive structure as set forth in claim 1 wherein said non-tacky layer is a solvent activated layer which is convertible to provide said tacky adhesive surface by the application of a solvent.

4. An adhesive structure as set forth in claim 1 wherein said non-tacky layer after being converted to provide a tacky surface is `adapted to ladhere to a surface of a body with an adherence sufficiently great to retain said nontacky layer with said surface of said body when said substrate is pulled away from said body.

5. An adhesive structure as set forth in claim 1 wherein the adherence between the surface of said pressure sensitive adhesive and said substrate is less than the adherence between the surface of said pressure sensitive adhesive Iand said non-tacky layer.

6. An adhesive structure as set forth in claim 5 wherein said non-tacky layer is a heat activated layer which is convertible to provide said tacky adhesive surface by the application of heat.

7. An Aadhesive structure as set forth in claim 5 wherein said non-tacky layer is a solvent activated layer which is convertible to provide said tacky adhesive surface by the application of a solvent.

(References on following page) References Cited UNITED STATES PATENTS Miller 1-61-406 X Moyses 117-6 5 Hartzel 161-167 Wurzburg 161-406 X Bennet 161-406 X Bennett 161-406 X 10 Drew 117-80 10 Banks et a1. 161-406 X Schram 117-45 Pahl et al. 161-167 Pahl et al. 161-16'7 Reed 117-76 EARL M. BERGERT, Primary Examiner.

M. L. KATZ, Assistant Examiner.

Disclaimer 3,343,978.Thomas J. Engelbaoh. Middletown, NJ. ADHESIVE TRANS- FERS. Patent dated Se t. 26, 1967. Disclaimer led June 2, 1972, by the assignee, Avery Pro uota Corporation. Hereby enters this disclaimer to claims 1-5 and 7 of said patent.

[Ooz'al Gazette J ulg 11, 1.972.]

Claims

1. AN ADHESIVE STRUCTURE COMPRISING A FLEXIBLE SUBSTRATE LAYER, A NON-TACKY LAYER, A PRESSURE-SENSITIVE ADHESIVE HAVING A FIRST SIDE IN ADHERING CONTACT WITH SAID SUBSTRATE LAYER AND A SECOND SIDE OPPOSITE SAID FIRST SIDE IN ADHERING CONTACT WITH SAID NON-TACKY LAYER, SAID NON-TACKY LAYER BEING CONVERTIBLE TO A LAYER HAVING A TACKY ADHESIVE SURFACE ON ITS SIDE OPPOSITE SAID PRESSURE-SENSITIVE ADHESIVE, THE ADHESION AT ONE OF SAID SURFACES OF SAID PRESSURESENSITIVE ADHESIVE BETWEEN SAID PRESSURE-SENSITIVE ADHESIVE AND THE ADJACENT ONE OF SAID LAYERS BEING LESS THAN THE ADHESION AT THE OTHER OF SAID SURFACES OF SAID PRESSURESENSITIVE ADHESIVE BETWEEN SAID PRESSURE-SENSITIVE ADHESIVE AND THE OTHER ONE OF SAID LAYERS, SAID PRESSURE-SENSITIVE ADHESIVE SEPARATING ALONG SAID ONE SURFACE THEREOF FROM THE ADHACENT LAYER AND REMAINING WITH SAID OTHER ADJACENT LAYER WHEN SAID LAYERS ARE PULLED APART.

5. AN ADHESIVE STRUCTURE AS SET FORTH IN CLAIM 1 WHEREIN THE ADHERENCE BETWEEN THE SURFACE OF SAID PRESSURE SENSITIVE ADHESIVE AND SAID SUBSTRATE IS LESS THAN THE ADHERENCE BETWEEN THE SURFACE OF SAID PRESSURE SENSITIVE ADHESIVE AND SAID NON-TACKY LAYER.