AU734527B2 - Method for packaging thermoplastic adhesive with sticky surface - Google Patents

Abstract

The invention concerns a method for the anti-adhesive treatment of a fusible adhesive with sticking surface, characterised in that it consists of the following successive steps: preparing the adhesive in a known manner in a mixer (1) at a temperature of about 130 to 150 DEG C; pumping the adhesive liquid coming from this mixer (1) and transferring it into a buffer vessel (4); lowering the temperature of the adhesive to about 65 to 85 DEG C, at which temperature it is in the form of a paste; simultaneously, applying on the adhesive in the vessel pressure up to 180 bars so as to enable its extrusion; and transferring the extruded adhesive into a dispensing head (6, 6') then into splitting and packaging means; collecting from the outlet thereof measured out blocks of adhesive, individually packaged in sealed bags made of thermoplastic polyester, in particular of polyolefine with a melting point higher than the temperature of the adhesive, preferably about 80 to 100 DEG C.

Description

P:'OPERJcc43884-97 s .do-05,02,01 -1- METHOD FOR PACKAGING THERMOPLASTIC ADHESIVE WITH STICKY

SURFACE

The present invention relates to a method for packaging a thermoplastic adhesive with a sticky surface, and to apparatus suitable for use in the method.

In many sectors of industrial chemistry it is standard practice to use thermoplastic adhesive compounds with sticky surfaces, i.e. materials which at handling temperature, generally room temperature, are characterised by one or more of the following criteria: intrinsic adhesiveness of the compound, tacky under normal temperature and pressure conditions, sensitivity to pressure, change in surface state with increasing temperature (for example in summer) Examples of areas in which such products can be used include the following list, which is not intended to be exhaustive: hygiene (full disposable nappies, feminine Sg 20 hygiene articles), structural bonding, semi-structural assemblages, carpets for the rear floor areas of vehicles, composite panels for building construction, ceiling tiles, wall coverings, re-usable pre-assembled panels, selfadhesive sill bars, peel-off or permanent envelope closures.

Bearing in mind the permanent adhesive nature of these materials, it is vital that they should be suitably packaged to enable them to be more conveniently handled, transported and stored.

•ge.

Moreover, packaging makes it possible to prevent .f0 several pieces of these materials from clumping together, as well as preventing impurities from being deposited thereon.

To this end, adhesives with sticky surfaces are conventionally supplied in waxed and silicone-coated trays, which make it possible to prevent any sticking.

However, this type of packaging is particularly costly and impractical, given the fact that the trays generally have a capacity of between 500 g and 3 kg, and that it is not unusual for users to have to "eject from the mould" a large quantity per day which can be as much as several tonnes.

In order to overcome these drawbacks, it has already been proposed to subject the adhesives to various packaging treatments enabling them to lose their surface tackiness and consequently to be directly packaged in bulk.

It has, for instance, already been proposed to coextrude a sheath surrounding the adhesive; the coextrusion material may, for example, be polyethylene or a non-self-adhesive hot melt that is compatible with the formulation of the extruded product (the FULLER process) It has likewise already been proposed to protect adhesive materials by electrostatically depositing a fine layer of anti-adhesive agent (by electrodeposition of a non-adhesive product on the S. surfaces of a moulded self-adhesive block (the RMC BELIX process) Likewise a method has already been proposed for spraying a non-self-adhesive hot melt contained in a mould (the CECA process) o These different treatment methods nevertheless have the drawback that they are costly, impractical and often difficult to implement continuously.

Independently of the above, from EP-A-0 141 087 there is known a method for the discontinuous antiadhesive treatment of an elastomer designed, once reatment is finished, to undergo a process of vulcanisation at the end of which it completely loses its stickiness. However, such an elastomer constitutes an intermediate product that is fundamentally different from an adhesive with sticky surface which is designed to be sold in that state.

There is likewise known, from EP-A-0 412 867, a method for the treatment of an adhesive with sticky surface which involves applying a coating of an antiadhesive agent that is compatible with the adhesive and does not entail significant physico-chemical modification thereof, over at least a portion of the surface of a ribbon of said adhesive emerging continuously from an extruder mixer or from a die, at a temperature higher than its softening temperature, cooling the ribbon thereby coated, and then cutting it to the desired length and directly packaging the pieces thereby obtained, without adopting additional precautions.

However, this method has not proved to be as advantageous in use as might have been hoped, particularly taking into account the fact that its implementation is complex and ill-suited to the production tooling: in particular it is to be noted that this method is especially temperature-sensitive, a variation of the order of 1 in the temperature of the adhesive being able to prevent it from being extruded.

The present invention seeks to overcome the oo above-mentioned drawbacks by proposing a new packaging method for a thermoplastic adhesive with a sticky Ssurface surface.

**o o* o*oo oo** P: OPER\kc43884-97 spcO.do-05,02,01 -3A- Accordingly, the present invention provides a method for packaging a thermoplastic adhesive with a sticky surface, comprising the successive steps of preparing the adhesive in a mixer at a temperature of 130 to 150 0

C,

transferring the prepared adhesive into a double-skinned buffer vessel having a peripheral annular chamber in which a cooling fluid circulates, thereby cooling the prepared adhesive to a temperature of 65 to 85 0 C at which it is in the form of a paste, extruding a ribbon ,6f the cooled adhesive from the buffer vessel, transferring said ribbon of the cold adhesive into a packaging zone, and collecting from the packaging zone measured-out blocks of adhesive, individually packaged in sealed bags made of a thermoplastic polymer having a melting point higher than the temperature of the packaged adhesive.

o o go *oo I ooo* I o**

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o -o P:'OPER'Jcc'43884-97 spC.doc-0502,01 -4- The packaging zone may comprise a dispensing head and means for dividing and packaging the cooled adhesive.

This method, which may advantageously be partially implemented continuously, does of course make it possible to package treat any thermoplastic adhesive with a sticky surface; examples of the materials that can be treated include the compounds listed below: formulations based on EVA, styrene-butadiene-styrene (SBS) or styrene-isoprene-styrene (SIS) copolymers; formulations based on resins and their derivatives resins of colophony, coumarone, indene, aliphatic and aromatic hydrocarbons); formulations based on styrene-ethylene-butylene (SEB) copolymers or styrene-ethylene-butylene-styrene (SEBS) copolymers; formulations based on partially crystalline vinyl copolymers; formulations based on polyesters or polyamides; more generally, any formulations obtained from a SD: 20 combination of the aforementioned polymers, *oe *e* P:'OPERycc'438S4.97 spMc.doc-O.02'01 copolymers, polycondensates and copolycondensates, possibly made up of termonomers of various types.

Preferably the thermoplastic polymer is a polyolefin.

As will be readily understood, the temperatures of the adhesive in the mixer on the one hand, and in the buffer vessel on the other hand, are in each case a function of the particular nature of that adhesive.

It should be noted that the choice of constituent polymer in the bags in which the blocks of adhesive are packaged, which depends in each particular case on the nature of the adhesive actually employed, is a critical factor of the invention: its melting point must actually be sufficiently high to avert the risk of being degraded by the adhesive during the packaging stage, and, in particular, not to risk being cross-linked by said adhesive. Conversely, said melting point must be sufficiently low to enable it to melt without residue with the adhesive when the user puts it to use.

In accordance with the invention, during the first e• 20 stage of the method it is possible to use a standard heliglobe mixer made up of a sphere fitted on the inside with rotary peripheral arms.

The buffer vessel has a double-skinned vessel equipped at its periphery with an annular chamber in which a cooling eeo 25 fluid can circulate. The temperature of the cooling fluid can be regulated.

Such a vessel may, furthermore, be fitted with means for measuring the temperature of the adhesive contained.

*oo P'OPERJcc43884-97 spec doc-0502.01 Adhesive from the mixer may be pumped and transferred to the buffer vessel. This may be achieved using a hydraulic press, the pressure exerted by which may be regulated.

In an embodiment of the invention extrusion of the cooled adhesive is achieved by applying a pressure of up to 180 bar to the cooled adhesive by means of a hydraulic pressure.

It should be noted that in some special cases where the adhesive is particularly fluid, it will not be possible to operate under pressure.

0* i *o *o**oo *ooo **oo *o P:'OPER'cc'43s84-97 sp.do-05,02 01 -6- The above-mentioned features make it possible to obtain a ribbon of adhesive at the outlet of the buffer vessel on the dispensing head, said ribbon generally having a consistency broadly similar to that of a toothpaste at a temperature of 65 to 85 0

C.

As a general rule the first part of the method is performed discontinuously. This is because preparation of the adhesive from basic ingredients usually takes about 4 hours and the fall in the temperature of the adhesive between 130 to 150 0 C (in the mixer) and 65 to 85 0 C (at the buffer vessel outlet) normally takes about 15 hours.

Consequently, to implement the method according to the invention, a plurality of buffer vessels are typically used which have a capacity smaller than that of the mixer; at the mixer's outlet the adhesive may be transferred in a first step to one of these vessels, where it begins to cool down, then in a second step in which the temperature drop continues, the vessel may be placed in a hydraulic press, for example with the aid of a fork-lift truck, and connected 20 to the dispensing head in a manner enabling the second part of the method to proceed, which advantageously may be performed continuously.

An important aspect of the invention relates to the control of various parameters involved in implementing the method: viscosity, temperature and pressure of the adhesive o in the buffer vessel, the flow rate of the ribbon coming from said vessel, etc.

To this end it is know that the viscosity of the adhesive is a decreasing substantially linear function of ooo the temperature.

What is more, it has been realised that at constant temperature the flow rate of the ribbon coming from the P.'OPERJcc'4384-97 spm.doc.-05,02O -7buffer vessel increases linearly as a function of the pressure prevailing in said vessel; different curves are naturally obtained in respect of each temperature, and for a given flow rate the higher the temperature is, the weaker is the associated pressure.

This linearity is broadly of a type facilitating the various controls necessary for implementing the method: this is because it is always advantageous to operate at the maximum temperature possible in order to enable the pressure to be reduced.

Taking this situation into account, and in accordance with one preferred feature of the invention the pressure applied to the adhesive is regulated in order to achieve a desired flow rate of the adhesive from the buffer vessel and wherein the temperature of the adhesive in the buffer vessel is regulated to ensure that the temperature of the adhesive is compatible with the melting temperature of the polymer used for the bags in which the adhesive is sealed.

It will be readily understood that this preliminary 20 operation must be repeated for each type of adhesive and for each type of film.

In an embodiment of the present invention, the dispensing head is fitted a controllable time-delay means which is adapted to suit the dividing means and which allows measured-out blocks of adhesive to be collected in succession at an outlet of said dispensing head, and wherein :Soo the measured-out blocks are individually packaged in bags by ee unwinding a reel of thermoplastic film vertically beneath •coo the dispensing head such that the film is supplied with ee successive measured-out blocks of adhesive, folding the film Rback on itself, welding the film around the blocks and cutting the film between blocks so as to obtain blocks P:'OPER'Jcc'438S4-97 spA.do00502,01 -8packaged in individual bags.

All that now remains is to cool the blocks so packaged, before storing them ready for distribution.

In accordance with the invention, the welding and cutting operation may be performed in horizontal welding machines or in per se known vertical welding machines, in which case the film is first folded lengthways back upon itself so as to obtain a continuous sleeve, and then welded and cut transversely.

According to a preferred embodiment of the present invention, individually packaged blocks of adhesive are obtained by unwinding a reel of the thermoplastic film onto a conveyor belt which is situated vertically below the dispensing head and which is travelling continuously, the film being provided in the form of a U-shaped section continuously introducing the adhesive into the U-shaped section pinching the upper edges of the U-shaped section and welding the edges iengthways so as to obtain a continuous ribbon of adhesive packed in a tube of the thermoplastic film, transferring the ribbon of adhesive thus packed to dividing and deforming means, which deforms said ribbon at regular intervals perpendicular to its longitudinal axis so te0 as to obtain a succession of blocks of constant dimensions separated by crush-bonding zones, and cutting the ribbon at SOC 25 the crush-bonding zones by cutting means.

It is advantageous to cool the ribbon at the crushbonding zones before making the cut, so as to avoid any risk 0 of adhesive leaking as a result of too high a temperature e g.

leading to defective leak-tightness.

*fee It is likewise advantageous to first flatten out the cA ribbon of adhesive in a pre-shaping device prior to transferring it into the dividing and deforming means.

P:'DPER'Jcc'43984-97 Sp.do.-05,02,01 -9- The present invention also provides an apparatus for carrying out the second (continuous) part of the method.

The apparatus comprises a substantially horizontal conveyor belt, one end of which is situated vertically beneath a dispensing head, said belt being fitted with means for forming the thermoplastic film into a U-shaped section, pinching means for pinching the upper edges of the U-shaped section of film, a horizontal welding means optionally a pre-shaping bar, dividing and deforming means, and cutting means.

Typically, the pinching means comprises two rollers with a vertical axis situated immediately next to one another. The welding means usually operates by hot air blasting. The pre-shaping bar is preferably of variable height.

According to a preferred feature of the invention, the dividing and deforming means comprises two endless conveyor belts which travel in synchromism one above the other, 20 situated directly downstream of the substantially horizontal conveyor belt and defining between them an intermediate S"space intended to receive a packaged ribbon of adhesive, the two endless conveyor belts being fitted at regular intervals with crushing control stops mounted perpendicular to the 25 forward travel axis of the belts and cooperating in pairs on either side of the intermediate space so as to enable the ribbon of adhesive to be deformed locally in order to obtain crush-bonding zones.

It is advantageous to mount the crushing control stops in a removable manner so as to make it possible to modify their respective spacing and, consequently, the position of the crush-bonding zones and the dimensions of the different P:'OPERJcc'43584-97 spm doc-05,02, 1 blocks.

Furthermore, and according to another feature of the invention, the crushing control stops are made up of cylinders which present a flattened area of a size matching the width of the crush-bonding zones.

Experience has shown that in order to obtain a sufficiently accurate cut, it is advisable to provide crushbonding zones having a width of at least somewhere around 12mm.

As a general rule, the cutting means are conventional cutting blades which cooperate with a presence sensor.

To be more precise, and in accordance with one particularly practical feature of the invention, the cutting means comprise a knife fixed on an actuator so as to be able to move to and fro in a horizontal plane substantially -perpendicular to the forward travel axis of the ribbon of adhesive, and cooperating with a camera associated with an analyser and with a visual display device in order to ensure that the cut is made exactly in the middle portion of the 20 crush-bonding zones.

The result of this is perfect synchronisation of the •cutting operation and of the passage of the adhesive ribbon beneath the knife, thereby avoiding any risk of adhesive leakage due to the cutting devices being badly positioned. *e In order to reduce this risk of leakage still further, and in accordance with another feature of the invention, the splitting and deforming means are fitted with nozzles which spray jets of cooling water.

This cooling may advantageously be carried out at two distinct locations, notably in the middle portion and at the R exit from the dividing and deforming means.

In accordance with the invention, upon leaving the P:OPERJc,43884-97 spM.do-05,02101 -11installation individual blocks of adhesive are obtained which can be recovered in order to be packaged in boxes.

By way of example only, the method and apparatus of the present invention will now be illustrated with reference to the accompanying drawings, wherein: Fig. 1 is a diagram representing an apparatus allowing the first aspect of the method to be implemented; Fig. 2 is a diagram representing an apparatus allowing the second aspect of the method to be carried out; Fig. 3 is a diagram representing the dividing and deforming means; Fig. 4 is a diagram representing the cutting means.

According to Fig. 1, the apparatus is schematically made up of a heliglobe mixer 1 comprising a sphere 2 fitted with rotating peripheral arms 3, a buffer vessel 4 which cooperates with a hydraulic press 5, and a dispensing head 6 fitted with time-delay means 7.

It should be noted that as a general rule the mixer 1 S• has a capacity of 2000 to 5000 litres, whereas the capacity 20 of the vessel 2 is twice or three times as great.

The constituent ingredients of the thermoplastic adhesive with sticky surface are introduced in the arrowed direction A into the mixer 1 and said adhesive is prepared e• therein in a manner known per se; it then leaves said mixer 25 1 at a temperature of about 130 to 150 0 C and is transferred, in the arrowed direction B and by means of a pump 8, into the buffer vessel 4, at which point its temperature has fallen to about 65 to 85 0

C.

As shown in the Figure, the vessel 4 is made up of a double-skinned receptacle equipped at its edge with an A annular chamber 9 in which a cooling fluid is circulated P:'OPER'Jcc'43884-97 spec do-05 02,01 12whose temperature can be regulated.

The buffer vessel 4 cooperates, moreover, with the hydraulic press 5, which acts on the adhesive present therein so as to enable it to be extruded in the form of a ribbon having a broadly similar consistency to that of a toothpaste.

On leaving the buffer vessel 4 this ribbon, the temperature of which is of the order to 65 to 85 0 C, is 13 transferred in the arrowed direction C into the dispensing head 6, at the outlet of which measured-out blocks 10 of adhesive are successively recovered.

As illustrated in Figure 1, the dispensing head 6 cooperates with packaging means 11 which allows the blocks 10 to be individually packaged in bags produced from a thermoplastic polyolefin having a melting point higher than the temperature of the adhesive, preferably about 80 to 100 °C.

These packaging means are essentially made up of a reel 12 situated in the vicinity of the dispensing head 6, and onto which is wound a polymer film 13, as well as of a per se known welding machine 14 which is fitted with welding devices 15, 15' and cutting devices 16.

In this machine 14, the film 13 is initially folded longitudinally back upon itself so as to obtain a continuous sleeve, then welded and cut transversely,.

According to Figure 2, the apparatus for treating the continuous ribbon of adhesive emerging in the arrowed direction D from the dispensing head 6' situated at the outlet of the buffer vessel 4 schematically comprises a substantially horizontal conveyor belt 20 which is constantly, moving translationally in the arrowed direction E, dividing and deformina means 21, and cutting means schematically represented by the double arrow

I.

A first extremity 22 of the conveyor belt 20 is situated directly beneath the dispensing head 6' so as to receive the adhesive ribbon emerging therefrom (arrow D), whereas its opposite extremity 23 is situated directly upstream of the dividing and deforming means 21 which will be described in greater detail below.

At its first extremity 22 the conveyor belt 20 cooperates with a reel 12' onto which the packing film 13' is wound.

The film 13' may be continuously unwound in the arrowed direction F so as to cover the upper surface of the conveyor belt The belt 20 is, moreover, equipped in its direction of travel E with means 24 for forming the packaging film 13', pinching means 25, weldinq means 26 and pre-shaping means 27.

At the forming means 24, which are made up of a wedge-shaped element with a U-shaped section, the film 13' is deformed into a spout 28, represented by dotted lines in the Figure, which receives the ribbon of adhesive in its inner portion.

Thereafter the free upper edges 29 of the spout 28 are held together in the pinching devices 25, which are made up of two rollers with a vertical axis (not shown) situated immediately next to one another, then welded lengthways by blasting hot air into the welding devices 26.

Consequently, when it emerges from these devices 26 a continuous ribbon of adhesive is obtained, packed in a tube of film 13'.

o:o: This tube is then flattened by the pre-shaping devices 27 which are made up of a single, heightadjustable bar e having a substantially perpendicular axis in the direction of travel E, beneath which the :oo: packed ribbon of adhesive is passed so as to obtain a flattened continuous ribbon 30 of packed adhesive.

According to Figure 3, said ribbon 30 is introduced in the arrowed direction G into the dividing and -deformiing devices 21, at the exit from which a succession of blocks a of constant dimensions is obtained, separated by crush-bonding zones b (Figure 2) The dividing and deforming means 21 are made up of two endless belts 31, 32 which travel in synchronism one beneath the other, as represented schematically by the arrows H and H' The two belts 31, 32 define between them an intermediate space 33 which receives the ribbon of adhesive 30 packed and flattened in the arrowed direction

G.

The belts 31, 32 are, moreover, fitted at adjustable regular intervals with crushing control stops 34 made up of cylinders presenting a flattened area (not shown) and mounted perpendicularly to the forward travel axis G.

The crushing control stops 34 cooperate pairwise at their flattened areas to either side of the intermediate space 33, so as to allow the ribbon 30 to be deformed locally when it is introduced between the belts 31, 32, and crush-bonding zones b to be obtained which *O separate the different blocks a.

The dividing and deforming means 21 are, moreover, equipped at two different locations with nozzles for spraying jets of cooling water (not shown in ooo Fig. 3) According to Figure 2, at the exit from the S: dividing and deforming devices a continuous packed ribbon of adhesive is thus obtained which is made up of a oooo !succession of blocks a separated by crush-bonding zones b and moving along a discharging belt 35 in the arrowed direction J; cutting this ribbon in the arrowed direction I at the crush-bonding zones b enables individual blocks a of individually packed adhesive to be obtained.

According to Figure 4, the cutting units are made up of a knife 36 fixed on an actuator (not shown), so as to be able to move to and fro in the arrowed direction X-X' in a horizontal plane substantially perpendicular to the forward travel axis J of the ribbon of adhesive.

Movement of the actuator is controlled by a schematically represented module 37 made up of a camera associated with an analyser and a visual display device, so as to ensure that the cut is made exactly in the middle portion of the crush-bonding zones b which separate the different blocks a.

Accordingly, at the exit from the cutting devices, individual blocks are obtained which can be recovered to be packed into boxes.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and o.

"comprising", will be understood to imply the inclusion .of a stated integer or step or group of integers or steps **c but not the exclusion of any other integer or step or group of integers or steps.

o o*o* The reference to any prior art in this specification is not, and should not be taken as, an o acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (3)

17- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. Method for packaging a thermoplastic adhesive with a sticky surface, comprising the successive steps of preparing the adhesive in a mixer at a temperature of 130 to 150 0 C, transferring the prepared adhesive into a double-skinned buffer vessel having a peripheral annular chamber in which a cooling fluid circulates, thereby cooling the prepared adhesive to a temperature of 65 to 85 0 C at which it is in the form of a paste, extruding a ribbon of the cooled adhesive from the buffer vessel, transferring said ribbon of the cold adhesive into a packaging zone, and collecting from the packaging zone measured-out blocks of adhesive, individually packaged in sealed bags made of a thermoplastic polymer having a :melting point higher than the temperature of the g. packaged adhesive. 2. The method of claim 1, wherein the packaging zone *S comprises a dispensing head and means for dividing and i. packaging the cooled adhesive. 3. The method of claim 1 or 2, wherein the temperature of *e the cooling fluid can be regulated. 4. The method of any one of claims 1 to 3, wherein 25 extrusion of the cooled adhesive is achieved by applying a pressure of up to 180 bar to the cooled adhesive by means of a hydraulic pressure. The method of any one of claims 1 to 4, wherein the thermoplastic polymer is a polyolefin. P:'OPERcJc'438S4.97 cains doc-05.02O01 18 6. The method of any one of claims 4 or 5, wherein the pressure applied to the adhesive is regulated in order to achieve a desired flow rate of the adhesive from the buffer vessel and wherein the temperature of the adhesive in the buffer vessel is regulated to ensure that the temperature of the adhesive is compatible with the melting temperature of the polymer used for the bags in which the adhesive is sealed. 7. The method of any one of claims 2 to 6, wherein the dispensing head is fitted with a controllable time- delay means which is adapted to suit the dividing means and which allows measured-out blocks of adhesive to be collected in succession at an outlet of said dispensing head, and wherein the measured-out blocks are 15 individually packaged in bags by unwinding a reel of thermoplastic film vertically beneath the dispensing head such that the film is supplied with successive "o measured-out blocks of adhesive, folding the film back on itself, welding the film around the blocks and 20 cutting the film between blocks so as to obtain blocks packaged in individual bags. S g 8. The method of claim 5 or 6, wherein individually packaged blocks of adhesive are obtained by unwinding a go reel of the thermoplastic film onto a conveyor belt .e 25 which is situated vertically below the dispensing head oo.o *and which is travelling continuously, the film being provided in the form of a U-shaped section continuously introducing the adhesive into the U-shaped section pinching the upper edges of the U-shaped section and 0 welding the edges lengthways so as to obtain a P:\OPERUcc43884-97 clains doc-29/03101 -19- continuous ribbon of adhesive packed in a tube of the thermoplastic film, transferring the ribbon of adhesive thus packed to dividing and deforming means, which deforms said ribbon at regular intervals perpendicular to its longitudinal axis so as to obtain a succession of blocks of constant dimensions separated by crush- bonding zones, and cutting the ribbon at the crush- bonding zones by cutting means. The method of claim 8, wherein the ribbon is cooled at 1: 0 the crush-bonding zones prior to cutting. S. The method of claim 8 or 9, wherein prior to transferring the packed ribbon of adhesive to the dividing and deforming means it is flattened by a pre- shaping bar. 15 11. Apparatus for carrying out the method of any one of e e claims 8 to 10, which apparatus comprises: •coo a substantially horizontal conveyor belt, one end oe of which is situated vertically beneath a dispensing head, said belt being fitted with means for forming a thermoplastic film into a U-shaped section, pinching means for pinching the upper edges of the U-shaped section of film, a horizontal welding means optionally a pre-shaping bar, dividing and deforming means, and cutting means. 12. The apparatus of claim 11, wherein the pinching means comprises two rollers with a vertical axis situated Ximmediately next to one another. P.'OPERJCc'43884-97 clim doc-05,02,01 13. The apparatus of claim 11 or 12, wherein the welding means operates by hot air blasting. 14. The apparatus of any one of claims 11 to 13, wherein the pre-shaping bar is of variable height. 15. The apparatus of any one of claims 11 to 14, wherein the dividing and deforming means comprises two endless conveyor belts which travel in synchromism one above the other, situated directly downstream of the substantially horizontal conveyor belt and defining between them an intermediate space intended to receive a packaged ribbon of adhesive, the two endless conveyor belts being fitted at regular intervals with crushing control stops mounted perpendicular to the forward travel axis of the belts and cooperating in pairs on 15 either side of the intermediate space so as to enable oooo the ribbon of adhesive to be deformed locally in order to obtain crush-bonding zones. 9.9 9• 16. The apparatus of claim 15, wherein the distance between the crushing control stops is adjustable. ooooo 20 17. The apparatus of claim 15 or 16, wherein the crushing control stops comprise cylinders presenting a flattened area of a size matching the width of the crush-bonding zones. .o o 18. The apparatus of any one of claims 11 to 17 wherein the dividing and deforming means comprise nozzles for spraying jets of cooling water.

19. The apparatus of any one of claims 11 to 18, wherein the cutting means comprise a knife fixed on an actuator P:'OPERJcc 43884-97 claims doc-05:02 01 -21 so as to be able to move to and fro in a horizontal plane substantially perpendicular to the forward travel axis of the ribbon of adhesive, and cooperating with a camera associated with an analyser and with a visual display device in order to ensure that the cut is made exactly in the middle portion of the crush-bonding zones. Method according to claim 1 and substantially as hereinbefore described with reference to any one of the accompanying figures.

21. The apparatus according to claim 11 and substantially as hereinbefore described with reference to any one of the accompanying figures. DATED this 6 t h day of February, 2001 15 Henkel France S.A. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s) a..o *o 9* a IO