WO2007039742A1

WO2007039742A1 - Web of printed matter coated with a thermo reactive adhesive and method of using the same

Info

Publication number: WO2007039742A1
Application number: PCT/GB2006/003698
Authority: WO
Inventors: Peter Andrew Carr
Original assignee: Skanem Uk Limited
Priority date: 2005-10-06
Filing date: 2006-10-04
Publication date: 2007-04-12
Also published as: GB0520305D0

Abstract

A method of applying printed matter to a package (20). A web (10) of substrate material having a reverse surface coated substantially entirely with a thermo reactive adhesive is provided. Sequential portions of the obverse surface of the web are printed with desired text and/or graphics. Portions are severed from the web and each severed portion (16) is applied to a respective package (20). Heat is applied to a selected area or areas (22a) of the reverse surface of each portion to activate the adhesive in said selected area (s) before the portion is applied to the package. Also, a reeled web (10) produced by part of the method and apparatus for use in the method.

Description

WEB OF PRINTED MATTER COATED WITH A THERMO REACTIVE ADHESIVE AND METHOD OF USING THE SAME

This invention relates to a method of printing and applying decorative designs used in packaging. The invention also relates to apparatus for use in the method, and to packages formed with decorative designs.

It is common practice to package products within cartons, boxes or trays which carry no print or decoration, and subsequently apply a label or sleeve carrying printed and/or graphic material which may be purely informational, but more commonly consists of or includes promotional material and brand imagery.

Labels are generally printed on gummed or self-adhesive stock, or are applied by machinery which inserts adhesive between the label and the package. Both of these have disadvantages. Gummed paper deteriorates in storage and can be difficult to handle in machinery. Self-adhesive stock generally requires the use of a releasable backing. Applying adhesive between a label and package is mechanically complex and limits line speed. It is also^' necessary to set up the adhesive applicator to match the required glue lines for different types or sizes of package.

An alternative is to provide sleeves around packaged products. A typical application is on foodstuffs packed in trays for sale in supermarkets, with the sleeves being used as a carrier for promotional messages. Hitherto, such sleeves have usually been of printed card but this has a number of disadvantages. The card is opaque, which limits the graphic effects which can be achieved and may obscure a part of the product which it is desired to allow the purchaser to see. The card is likely to be degraded by moisture or frost. Applying a card sleeve requires relatively complex machinery and the use of an adhesive applicator.

i The present invention provides a method of applying printed matter to a package, comprising: providing a web of substrate material having a reverse surface coated substantially entirely with a thermo reactive adhesive; and printing sequential portions of the obverse surface of the web with desired text and/or graphics; severing portions from the web and applying each severed portion to a respective package; and in which heat is applied to a selected area or areas of the reverse surface of each portion to activate the adhesive in said selected area(s) before the portion is applied to the package.

Preferably, the application of heat takes place after the portion has been severed and immediately before application to the package.

The printed web may be re-reeled and transported to a separate location for unreeling, severing, heating and application. Alternatively, the web may be utilised direct from printing.

The web may be of paper or of plastics film. Paper may be of any suitable type and typically between 80 and 120 g/m². Suitable plastic films may be polyesters, polypropylenes (preferably BOPP - bi-axially orientated polypropylene), a laminate comprising a layer of polyester and a layer of polypropylene, or any other suitable material known in the art. Where a laminate of polyester and polypropylene is employed, the adhesive is preferably applied to the surface of the polyester layer.

The portions may be applied to packages as labels or as sleeves. In the latter case, the severed portion may be wrapped around the package and adhered to itself. Heat may suitably be supplied by a radiant heating element. Preferably, the radiant heating element comprises separately controllable heating areas. The heating areas may be arranged in a 2D array, or in the form of a transverse row of heating areas which can be activated to produce selected heated stripes on the moving web material. The heating areas are preferably controlled by a local control circuit comprising a memory.

The invention, in another aspect, resides in a reeled web of substrate material having a reverse surface substantially entirely coated with a thermo reactive material and an obverse surface having sequential portions printed with text and/or graphics.

From another aspect, the invention provides apparatus for use in the foregoing method, the apparatus comprising a reel stand for holding a reeled web as defined above, means for unreeling the web, means for severing the web into portions, and means for applying said portions to respective packages, the apparatus also including heating means disposed to apply heat to selected areas of the reverse surface to activate the adhesive in said selected areas.

The heating means is preferably disposed between the severing means and the application means.

The heating means preferably applies radiant heat, and may suitably comprise an array of heating areas separately controllable to define said selected areas in a variety of patterns. Said array may, for example, comprise a 2D array in a matrix, or a row of heating areas cooperating with movement of the severed web material to produce selected stripes of activated adhesive. An embodiment of the invention will now be described, by way of example only, with reference to the drawings, in which:

Fig. 1 is a schematic side view of an apparatus forming part of the present invention;

Fig. 2 is a plan view of part of the apparatus of Fig. 1 ; and Fig. 3 is an end view corresponding to Fig. 2.

The process of the present embodiment starts with a reeled web of a suitable substrate having its reverse face coated with a thermo reactive pressure sensitive adhesive. Substantially all of the reverse surface is coated with the adhesive, that is all of the surface possibly excluding minor portions such as edges which may be trimmed off.

The web may be of paper or of plastics film. Suitable grades of paper are for example those of weight between 80 and 120 g/m². Suitable plastics films are for example polyesters, polypropylenes (preferably BOPP - bi- axially orientated polypropylene) or a laminate comprising a layer of polyester and a layer of polypropylene. The adhesive is suitably one which is inert and non-tacky until activated by being heated. A suitable activation temperature is at least 80^QC. Among suitable adhesives are heat-activated, thermoplastic hot melt adhesives, generally known in the art.

The web is unreeled and printed on the obverse surface by any suitable process. The preferred process is UV flexography, especially where plastic film is used as the substrate, but the invention may be operated with any printing process appropriate to the substrate. The printing process used will be entirely standard and is therefore not described further herein. It is also possible to add printing on the reverse surface where this is compatible with the adhesive used.

The printed matter comprises text and/or graphics printed repetitively on successive portions of the web, the portions corresponding to the size required for application to the eventual packages.

After printing, and any desired finishing process such as edge trimming or slitting, the printed web is re-reeled on a suitable carrier.

Thus, the initial stages of the process can be carried out in any convenient print works and the re-reeled web transported to the point of use.

Referring now to Fig. 1 , the re-reeled web 10 is unreeled by drive rolls 12 and severed by a guillotine 14 into individual portions 16. The printed matter may include index marks which can be used to accurately align the printed matter with the guillotine.

The reverse face of the portion 16 is then heated by a heater assembly 18 to activate parts of the adhesive, and the portion 16 is then applied to a package 20 by any suitable known form of applicator.

Referring to Figs. 2 and 3, the preferred form of heater assembly 18 comprises a thermal print head, of a type known in the art.

In the embodiment shown, the severed web portion 16 is held stationary adjacent the heater assembly 18, which comprises elongate heating areas 22. Selected ones of the areas 22, for example those shown as 22a, are energised to activate corresponding stripes 24 of the adhesive. The elongate heating areas 22 could be replaced by a 2D array of squares or dots.

Instead of using a 2D array of heat elements, a row of heat elements may be used in conjunction with movement of the web or web portion past such elements.

Whichever of these is used, the heater assembly preferably includes a controller (not shown) which selects the areas to be energised at any given time. The controller may include a memory into which the necessary control information is loaded, for example in the form of a bitmap.

In principle, the adhesive could be activated before the web is guillotined, but activation after severing is preferred as the web is non-tacky in the guillotine.

The apparatus of Fig. 2 may optionally include a further printer, such as an inkjet printer, for printing information such as a catchweight or a best before date on the label or sleeve.

The portion applied to the package is most suitably applied as a label, with the web portion being adhered to a packaging element such as a carton, or as a sleeve wrapped round the package, in which case the adhesive may be activated such that one end (or side) of the sleeve is adhered to an opposed end (or side) of the sleeve. Other forms of use are possible, such as enclosing the entire package.

The invention provides a number of advantages. The use of a thermaily activated adhesive means that printing, re-reeling, storage and transport are facilitated. The selective activation of parts only of the adhesive, coupled with selective guillotining to size, means that a single form of stock can be used for a wide range of package types and sizes and for a variety of label and sleeve sizes, thus giving a high degree of manufacturing flexibility.

Modifications and improvements may be made to the foregoing embodiments within the scope of the invention.

For example, an adhesive may be used which is dual activated by application of both heat and pressure, with means for applying the pressure in addition to means for applying heat being incorporated within the method and within the apparatus.

Claims

1. A method of applying printed matter to a package, comprising: providing a web substrate material having a reverse surface coated substantially entirely with a thermo reactive adhesive; printing sequential portions of the obverse surface of the web with desired text and/or graphics; and severing portions from the web and applying each severed portion to a respective package; and in which heat is applied to a selected area or areas of the reverse surface of each portion to activate the adhesive in said selected area (s) before the portion is applied to the package.

2. A method according to claim 1 wherein the application of heat takes place after the portion has been severed and immediately before the application to the package.

3. A method according to claim 1 or claim 2 wherein the printed web is re-reeled and transported to a separate location for unreeling, severing, heating and application.

4. A method according to claim 1 or claim 2 wherein the web may be utilised direct from printing.

5. A method according to any of claims 1 to 4 wherein the web is of paper or of plastics film.

6. A method according to claim 5 wherein the plastics film is polyester, polypropylene or a laminate comprising a layer of polyester and a layer of polypropylene.

7. A method according to claim 6 comprising a plastics film laminate of polyester and polypropylene, wherein the adhesive is applied to a surface of the polyester layer.

8. A method according to any preceding claim wherein the portions are applied to packages as labels.

9. A method according to claim 8 comprising portions applied as sleeves, wherein the severed portion may be wrapped around a package and adhered to itself.

10. A method according to any preceding claim wherein heat is supplied by a radiant heating element.

11. A method according to claim 10 wherein the radiant heating element comprises separately controllable heating areas.

12. A method according to claim 11 wherein the heating areas are arranged in a 2D array or in the form of a transverse row of heating areas which can be activated to produce selected heated stripes on the moving web material.

13. A method according to claim 12 comprising heating areas wherein the heating areas are controlled by a local control circuit comprising a memory.

14. A reeled web of substrate material having a reverse surface substantially entirely coated with a thermo reactive material and an obverse surface having sequential portions printed with text and/or graphics.

15. Apparatus for use in the method according to any of claims 1 to 13, the apparatus comprising a reel stand for holding a reeled web as defined above, means for unreeling the web, means for severing the web into portions, and means for applying said portions to respective packages, the apparatus also including heating means disposed to apply heat to selected areas of the reverse surface to activate the adhesive in said selected areas.

16. Apparatus according to claim 15 wherein the heating means is disposed between the severing means and the application means.

17. Apparatus according to claim 16 wherein the heating means is a radiant heating element.

18. Apparatus according to claim 17 wherein the radiant heating element comprises an array of heating areas separately controllable to define said selected areas in a variety of patterns.

19. Apparatus according to claim 18 wherein the array comprises a 2D array in a matrix or a row of heating areas cooperating with movement of the severed web material to produce selected stripes of activated adhesive.