MXPA96004397A - Autoadhesi stamps - Google Patents

Abstract

The invention provides self-adhesive stamps consisting of: a layer (2) of stamp paper having a stamp design printed on its front and having perforated edges (6), a layer of pressure-sensitive adhesive (5) on the part back of the stamp paper, and a sheet or sheet of peel backing (7) covering the adhesive, wherein the pressure sensitive adhesive layer has a pattern so that there is little or no adhesive adjacent to the perforated edges of the paper of stamp. Preferably, the pressure sensitive adhesive is a hot-melt adhesive, and preferably the adhesive is applied by printing. The invention also provides a method for manufacturing such stamps, comprising the steps of: providing a sheet or net of stamp paper having lines or perforations defining stamps thereon, followed by coating on the back of the stamp paper with a layer in the form of a pattern of pressure-sensitive adhesive and a backing sheet

Description

AIJTCJ.DHESIVAS STAMPS DESCRIPTION OF THE INVENTION The present invention relates to self-adhesive stamps which can be used for various purposes, such as tax stamps, discount stamps, savings stamps, gift stamps, etc. In particular, it relates to self-adhesive postage stamps. Conventional postage stamps are provided with a water-soluble adhesive backing layer which must be moistened before affixing the postage stamps to a wrapping or mail piece. In recent years, a demand for self-adhesive postage stamps has been developed that is provided with a pressure-sensitive adhesive coating that does not need to be dampened before use. Such self-adhesive stamps are simply separated from the releasable support sheet and then pressed onto a wrapping or mail piece. The layer of pressure sensitive adhesive forms a bond between the stamp and the substrate of the mail piece. In this way, the discomfort and discomfort of the necessary wetting step in conventional postal stamps is avoided. REF: 23154 The existing self-adhesive postage stamps are manufactured from a self-adhesive label material or a self-adhesive material prepared for the purpose. The self-adhesive material consists of a coated paper sheet attached to a backing sheet detachable by a layer of pressure-sensitive adhesive. The backing sheet can be peeled off (or the stamp can be peeled off a backing board) to expose the pressure sensitive adhesive, which has been applied as a total coating. The pressure sensitive adhesive is usually a water based polymer adhesive. Self-adhesive postage stamps are made from the adhesive material by first printing a plurality of postage stamps on the prepared material, followed by die cutting the coated paper (but not usually on the backing sheet) along the the edges of the postage stamp designs, so that individual postage stamps can be detached from the holder. Self-adhesive postage stamps manufactured in this way are currently available in several countries including France, Australia and the United States. Self-adhesive prints consisting of a stamp paper layer and a layer of pressure-sensitive adhesive mounted on a backing sheet are described in GB-A-1414777, GB-A-2048817 and DE-A-4215834.

Self-adhesive postage stamps manufactured as described above suffer from numerous drawbacks. First, the coated paper used to make the label material normally is not ideally suited for high quality postage stamps. When printed on a paper which is part of a self-adhesive interlayer, it is rarely possible to obtain a better print quality. The coating on the paper may or may not contain luminescent compounds 'xO which are normally included in postage stamp papers for recognition by automatic sorting machines. What is even more important, the cancellation marks that are applied to stamps by the Post Office can sometimes be cleaned from the coated papers used to make the self-adhesive material. A second drawback of the above method is the impracticality of making traditional drill holes with the adhesive and the release support in place. situ. The problem is that the adhesive-coated paper pieces that are punctured by a conventional punching die tend to stick in groups that can not be handled and which clog the drilling machinery. This means that the self-adhesive stamps obtained by the previous process currently do not have perforated edges. That is to say", have no edges with the characteristic profile produced by tearing or die cutting along a line of perforations (such as a line of circular holes of approximately 0.75 - 1.2 mm in diameter separated by 0.2 - 0.8 mm, measured between the edges of adjacent holes). The absence of perforated edges makes the falsification of stamps easier, and results in reduced user acceptance. This drawback has been solved by making die edges around the stamps using a die cutting tool having a zigzag-shaped or wave-shaped blade in a manner that simulates the appearance of perforated edges. However, stamps produced in this way are always easily distinguishable from stamps that have true perforated edges when examined by experienced people. A third drawback of the self-adhesive stamps produced according to the existing technique is the leakage of adhesive through the die cut lines in the stamp paper. This leakage of adhesive can cause unwanted adhesion between sharp or rolled sheets of self-adhesive stamps. A fourth drawback of the self-adhesive stamps produced according to the existing technique is that the combined thickness of the coating paper, the adhesive and the backing sheet is difficult to bend into precisely folding sheets supplied by the stamp vending machines. postcards or that are sold in notebooks or wallets (groups or bundles of tickets) in the post offices and in other places of retail sale. Accordingly, it is an object of the present invention to provide improved self-adhesive stamps that overcome the above drawbacks of the existing art. It is a further object of the present invention to provide a simple, efficient and productive method for manufacturing such improved self-adhesive stamps. The method allows the manufacture of products based on conventional stamps currently produced worldwide in self-adhesive form without variation in printing method, print quality, quality of drilling holes or general visual appearance. The present invention provides a self-adhesive stamp consisting of: a layer of stamp paper having perforated edges; a layer of pressure-sensitive adhesive on the back of the backing of the stamp paper; a removable backing sheet covering the adhesive, characterized in that the pressure sensitive adhesive layer has a pattern so that there is little or no adhesive adjacent to the perforated edges of the stamp paper. The term "perforated edges" means that the edges of the stamp paper have the characteristic profile produced by tearing or die cutting along a line of perforations. The perforations can be circular, polygonal, star-shaped or in more complex shapes. However, preferably the perforations are circular. Preferably, the circular perforations have a diameter of 0.75-1.2 mm and are 0.2-0.8 mm apart, measured between edges of adjacent holes. Providing self-adhesive stamps having genuinely perforated edges is an important feature of the present invention. Such self-adhesive stamps are more difficult to forge than the previous self-adhesive stamps and are more acceptable to the public. Preferably, the stamp is a postage stamp. Preferably, the stamps form part of a sheet or stamp spool, in which the individual stamps are preferably separated from each other by lines of perforations. The stamps according to the present invention can be part of a sheet or stamp spool which additionally comprises stamps which are not within the scope of the invention, for example, stamps having only one layer of wettable adhesive. The term "stamp paper" comprises any kind of paper suitable for the manufacture of stamps. Preferably, the front face of the stamp paper is provided with a coating containing, in addition to other components, luminescent pigments for recognition by automatic orientation, cancellation and sorting machines. Preferably, the front face of the stamps is printed with a stamp design, such as a postage stamp design. Preferably, the front face of the stamp paper is coated in a manner that permanently retains the cancellation marks applied on the paper by the post office or by the authority using it. In fact, the stamp paper is preferably similar to, or is the same as, paper conventionally used for the manufacture of postage stamps having a water-soluble adhesive coating. In certain preferred embodiments, the security of the stamp is improved by providing shaped perforations, known as perforated initials in the central part of the stamp paper away from the perforated edges.

The pressure sensitive adhesive may be comprised of any of the adhesives of this type commonly known in the art. For example, the pressure sensitive adhesive can be a water soluble acrylic adhesive. Preferably, however, the pressure sensitive adhesive is a heat-melting adhesive. The pressure sensitive adhesive can be applied by any of the methods that impart a controlled pattern to the adhesive. Preferably, the pressure-sensitive adhesive layer is printed or covered by slots in the back of the stamp paper, or in some cases it can be applied similarly to the backing sheet and then laminated with the backside of the stamps. The pressure sensitive adhesive does not cover the entire back surface of the stamp paper, instead it forms a pattern so that there is little or no adhesive adjacent the perforated edges of the stamp paper. Preferably, a free margin of adhesive of 0.1 to 5 mm, preferably 1 to 4 mm, is left between the perforated edges of the stamp paper and the edge of the pattern of the pressure sensitive adhesive. This ensures that there is no leakage of adhesive through the perforations towards the front of the stamps. In addition, it makes it easier to detach the stamps from the backing sheet, since the edges of the stamps do not adhere to the backing sheet. Preferably, the release backing sheet is a coated release foil, such as a silicone coated paper.Preferably, the backing sheet may also be a polymer film, such as a biaxially oriented polypropylene film. , which can be covered with silicone, preferably the self-adhesive stamp according to the present invention additionally comprises a layer of water-releasable adhesive sandwiched between the stamp paper and the layer of pressure-sensitive adhesive. Preferably, the water-releasable adhesive is a wettable adhesive of the type conventionally used for postal stamps.The purpose of this intermediate layer of water-releasable adhesive is to enable philatelists to remove the stamp from an envelope when applying steam or moistening. it is difficult and not particularly efficient if there is only one layer of adhesive sensitive to the p ression between the stamp paper and the envelope or the postal item. The present invention also provides a method for manufacturing self-adhesive stamps, comprising the steps of: providing a roll or sheet of stamp paper and providing lines of perforations in the stamp paper defining a plurality of stamps, followed by application of a layer of pressure sensitive adhesive and a removable backing sheet on the back of the stamp paper, characterized in that the pressure sensitive adhesive is applied in a pattern so that there is little or no adhesive applied to the back of the sheets. stamps adjacent to the perforation lines. Preferably, the stamp paper is a conventional stamp paper of the type used to print conventional postage stamps. Such a paper is preferably provided with a continuous layer of wettable adhesive at the rear thereof. Preferably, the pressure-sensitive adhesive layer is applied to the back of the perforated stamp paper, and the perforated, adhesive-coated layer is then laminated with the release backing sheet. However, it is also possible to coat the layer of pressure sensitive adhesive on the backing sheet and then to laminate the coated backing sheet on the stamp paper. The method of the present invention provides the advantage that stamps can be printed using conventional roll or sheet printing techniques, such as printing by roll engraving, on conventional stamp paper which is optimized for such printing and which can also be provided with luminescent coatings suitable for recognition by automatic sorting machines. The printing can be carried out before the piercing step, or preferably it can be carried out after the step of applying the pressure sensitive adhesive and the support sheet. Preferably, the pressure sensitive adhesive is a hot-melt adhesive. This is preferred because the heat-melting adhesive can be applied in one step, without the need for subsequent drying of the adhesive and therefore has minimal impact on the stability of the stamp. In contrast, a conventional acrylic adhesive or other pressure sensitive adhesive of polymers is usually applied in aqueous solution and then dried. This involves an additional stage of drying, and the water (or other solvents used) can cause wrinkling, distortion or other problems with the stamp paper. The pressure sensitive adhesive can be applied to the back of the stamp paper or to the backing sheet by any conventional means to apply a patterned layer, such as a die, slot die or roller. Preferably, the pressure sensitive adhesive is applied on the back of the stamp paper to the backing sheet by printing, more preferably by screen printing. This allows an accurate pattern formation of the pressure sensitive adhesive layer. In particular, it allows the pressure sensitive adhesive to be applied in a pattern or pattern so that there is no adhesive adjacent the perforated edges around each stamp. Preferably, a free margin of adhesive of a width of 0.1-5 mm, more preferably 1-4 mm, is left on the back of each stamp around the perforated edges of each stamp. The advantages of such an adhesive layer with a pattern are described above. After the application of the adhesive layer and the backing sheet, the method preferably further comprises the step of punching the roll of stamp paper along the length of one or more lines of perforations. This allows the individual stamps to be detached from the backing sheet. The die cutting line is preferably a straight line running down the middle of the perforation lines, whereby the stamps are provided with the perforated edge profile characteristic of conventional stamps. The resulting roll of self-adhesive stamps affixed to the backing sheet can be cut into smaller sheets or sheets and / or rolled into rolls or made into books or wallets (checkbooks). The roll can also be easily folded along the perforation lines provided in the stamp paper. This preferably bent is aided by providing marked lines or lines of perforations in the support sheet corresponding to the desired doubles lines. Preferably, the self-adhesive stamps are made in a separate arrangement on the backing sheet, thereby making the stamps easier to detach from the backing sheet and make it easier to fold the stamp sheets. Alternatively, for a stamp material that is not separate, the backing paper is offset printed in alignment to facilitate further detachment by the user. The separate stamps are made by printing the plurality of stamp designs on the stamp paper roll in a corresponding separate arrangement with a frame or white stamp paper structure defined by the lines of perforations around the stamp designs. After, by following the application of the release backing sheet and the adhesive layer, the stamp paper is cut by die along the lines of perforations and the frame is peeled off and removed, thereby leaving a plurality of stamps joined to the support sheet in a separate manner. Preferably, little or no pressure sensitive adhesive is applied to the back of the frame, thereby making the frame easy to detach from the backing sheet, easy to remove and roll up, and easy to discard. This is an important advantage of the method of the present invention. The specific embodiments of the self-adhesive stamps and the method of their manufacture according to the present invention will be described further below, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a view in elevation side of the stamp in accordance with the present invention (the relative vertical dimensions have been exaggerated for clarity); Figure 2 shows a rear plan view of the stamp of Figure 1, with the support sheet removed; Figure 3 shows a schematic view of the steps in a method for manufacturing a self-adhesive stamp (which excludes printing and final finishing) according to the present invention; and Figure 4 shows a plan view of a small part of a roll of stamp paper for use in the method of producing self-adhesive stamps which are separated on a backing sheet. With reference to figure 1, the self-adhesive stamp (1) is constituted by a layer of stamp paper (2) of the type conventionally used to print postage stamps according to the existing technique, which is provided with a layer of adhesive soluble in water, humid, only. A postage stamp design is printed on the front surface (3) of the stamp paper, and the front of the stamp paper can also be coated with an organic (or inorganic) luminescent pigment for recognition by automatic sorting machines. The back face of the stamp paper is completely covered with a layer (4) of releasable, water-moistening adhesive of the type that is applied to conventional postage stamps. Beneath the layer (4) of releasable water-wettable adhesive, a layer (5) of pressure-sensitive adhesive, which is melted by heat, is provided. The layer (5) of pressure sensitive adhesive does not extend in its entirety towards the edges (6) of the stamp paper. The heat-melt adhesive is a synthetic thermoplastic rubber based adhesive for application at 150 to 170 ° C and is available from The National Starch Chemical Company Limited under catalog number 089-1540. The weight of the heat-melting adhesive is 10 to 25 grams per square meter, preferably 15 to 20 grams per square meter, more preferably about 171/2 grams per square meter. The layer (5) 'of pressure sensitive adhesive is coated with a release sheet or sheet (7) of paper coated with silicone release. The particular paper used in this mode is available from Cote Limited under the reference BD 45, and has a weight of 45 grams per square meter. With reference to Figure 2, it can be seen that the stamp (1) has perforated edges (6) formed by making a straight cut along the center of a line of circular perforations. The layer (5) of pressure-sensitive adhesive is stamped in a rectangular pattern in the center of the stamp, leaving a margin (8) of approximately 3 mm adhesive-free width around the edges of the stamp. stamp. This prevents leakage of the adhesive around the perforated edges of the stamp towards the front face of the stamp, and also facilitates the detachment of the stamp from the backing sheet. With reference to Figure 3, the self-adhesive stamps are manufactured as follows. First, a roll of stamp paper having its back surface completely covered with the postmark adhesive releasable with conventional water, • is printed with a plurality of stamp designs on one side and pierced in the same manner as for the manufacture of conventional stamps. This produces a roller (9) of a printed and perforated roll. In alternative embodiments, the printing stage can be omitted or left to a later stage in the process. The roll (10) is then unrolled from the roller (9) and fed continuously into a screen printing machine (11) which prints the pattern of the heat-melting adhesive on the back surface of the stamp paper, in alignment with printed stamp designs. The screen stenciling machine (11) is a hot melt stencil stamping machine available from Meltex GmbH of Lüneburg, Alemina or from Nordson Coporation, Norcross, Atlanta, U.S.A. After the stencil stamping step, a continuous roll (12) of the material of the backing sheet is applied to the adhesive coated surface of the stamp paper roll by the rollers (13). Optionally, the backing sheet is printed with a roll printer (14) before being applied to the stamp paper roll. The roll (15) with resultant interlayers subsequently enters a die cutting apparatus (16), in which die cuts are made through the stamp paper along part or all of the perforation lines in the stamp paper. When appropriate, the frame (17) of the stamp paper between the separate stamps is detached and removed and can be rolled up. The roll of the backing sheet material having the self-adhesive stamps on it (18) is wound on a roll (19) or can be placed on sheets and on (24). The roll (19) may then undergo additional processing to separate the sheets, to fold the sheets, to form wallets or checkbooks or other retail formats. In alternative embodiments, the printing of the stamp designs on the front face of the stamps can be carried out at this stage. Figure 4 shows in detail a section of the perforated printed roll (20) of the stamp paper which is used to manufacture stamps according to the present invention separated into a sheet or backing sheet of detachable support material. The roll tends individual stamp designs (21) printed separately with lines of perforations (22) around each stamp design (21). In the adhesive coating step, the heat-melting adhesive is printed on the back side of the stamp paper roll only on the underside of the stamp designs (21). The backing sheet is then applied, followed by die cutting along the perforation lines (22). The frame (23) of the stamp paper between the individual stamps can simply be peeled off and removed, which leaves the individual stamps separated on the backing sheet. The frame can be rolled up and disposed of, or recycled. The above specific embodiments of the present invention have been described by way of example only. Many other embodiments are within the scope of the appended claims as will be apparent to a reader skilled in the art. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following:

Claims (22)

1. A self-adhesive stamp, characterized in that it comprises: a layer of stamp paper having perforated edges, a layer of pressure-sensitive adhesive on the back of the stamp paper and a sheet or peel-off backing sheet covering the adhesive, wherein the pressure sensitive adhesive layer forms a pattern so that there is little or no adhesive adjacent the perforated edges of the stamp paper.

2. The self-adhesive stamp according to claim 1, characterized in that a margin of 0.1-5 mm is left between the perforated edges of the stamp paper and the edge of the layer of pressure-sensitive adhesive.

3. The self-adhesive stamp according to claim 1 or 2, characterized in that the stamp forms part of a rolled sheet or coil of stamps separated by lines of perforations.

4. The self-adhesive stamp according to claims 1, 2 or 3, characterized in that the pressure-sensitive adhesive is a hot-melt adhesive.

5. The self-adhesive stamp according to any preceding claim, characterized in that the layer of pressure-sensitive adhesive is printed or punched by coated grooving on the back of the stamp paper.

6. The self-adhesive stamp according to any preceding claim, characterized in that the peelable backing sheet is a coated board or board, releasable from peelable coated paper or a polymeric film which can be coated for release.

7. The self-adhesive stamp according to any preceding claim, characterized in that it additionally comprises a layer of water-releasable adhesive, between the paper of the stamp and the layer of pressure-sensitive adhesive.

8. The self-adhesive stamp according to any preceding claim, characterized in that "" 'additionally comprises a luminescent material applied to the front surface of the stamp.

9. The self-adhesive stamp according to any preceding claim, characterized in that it additionally comprises a printed stamp design on the front surface of the stamp.

10. A method for manufacturing a self-adhesive stamp, characterized in that it comprises the steps of: providing a roll or sheet of stamp paper and providing lines of perforations in the stamp paper defining a plurality of stamps, followed by application of a layer of stamp. adhesive 15 pressure sensitive and a peel backing sheet on the back of the stamp paper, wherein the pressure sensitive adhesive is applied in a pattern so that there is little or no adhesive applied to the back of the stamps adjacent to the lines of 20 perforations.

11. The method according to claim 10, characterized in that the free margin of adhesive of 0.1-5 mm wide is left in the rear part 25 of the stamps adjacent to the perforation lines.

12. The method according to claim 10 or 11, characterized in that a plurality of stamp designs are printed on the roll or sheet of stamp paper before the lines or perforations are provided in the stamp paper.

13. The method according to claim 10 or 11, characterized in that a plurality of stamp designs are printed on the roll or sheet of stamp paper after the steps of perforating and applying, and in alignment with a plurality of stamps.

14. The method according to any of claims 10 or 4, characterized in that the step of applying comprises the steps of: coating the layer of pressure-sensitive adhesive on the back of the perforated stamp paper, followed by lamination of the backing sheet on the coated and perforated stamp paper.

15. The method according to any of claims 10 to 13, characterized in that the step of applying comprises the steps of: coating the layer of pressure-sensitive adhesive on the release backing sheet, followed by lamination of the coated backing sheet , on the perforated stamp paper.

16. The method according to any of claims 11 to 15, characterized in that the pressure sensitive adhesive is a hot-melt adhesive.

17. The method according to any of claims 11 to 16, characterized in that the layer of pressure-sensitive adhesive is coated on the back of the stamp paper or on the backing sheet by stenciling or by die-coating and slotting .

18. The method according to any of claims 10 to 17, characterized in that it additionally comprises the steps of, subsequent to the support sheet, die cutting the roll of stamp paper along one or more of the lines of perforations.

19. The method according to any of claims 10 to 18, characterized in that it additionally comprises the step of cutting with die the support sheet or perforating the support sheet.

20. The method according to any of claims 10 to 18, characterized in that the plurality of stamps are separated on the stamp paper, with a 'frame or stamp paper structure between the stamps defined by the lines of perforations around the stamps. , and the method further comprises the steps of: following the application of the release backing sheet, die cutting along the lines of perforations and detaching the frame, whereby a plurality of stamps attached to the sheet are left of support separately.

21. A self-adhesive stamp, characterized in that it is substantially as described in the foregoing with reference to figures 1 and 2.

22. A method for manufacturing a self-adhesive stamp characterized in that it is substantially as described in the foregoing, described with reference to Figures 3 and 4. The invention provides sutcebhß3iv stamps which are composed of: a ply, ply, ply (2) layer having a stamp design printed on its front and having perforated edges (6), a layer of pressure-sensitive adhesive ( 5) on the back of the stamp paper, and a sheet or peel backing sheet (7) covering the adhesive, wherein the pressure sensitive adhesive layer has a pattern so that there is little or no adhesive adjacent to the adhesive. the perforated edges of the stamp paper. Preferably, the pressure sensitive adhesive is a hot-melt adhesive, and preferably the adhesive is applied by printing. The invention also provides a method for manufacturing such stamps, comprising the steps of: providing a sheet or network of stamp paper having lines or perforations defining stamps thereon, followed by coating on the back of the stamp paper with a pattern-shaped layer of pressure sensitive adhesive and a removable backing sheet.