WO2008122864A1

WO2008122864A1 - Biadhesive element

Info

Publication number: WO2008122864A1
Application number: PCT/IB2008/000810
Authority: WO
Inventors: Angelo Lorenzo Carraro
Original assignee: ALC FLENCO GROUP Srl
Current assignee: ALC FLENCO GROUP Srl
Priority date: 2007-04-06
Filing date: 2008-04-04
Publication date: 2008-10-16
Anticipated expiration: 2009-10-06
Also published as: ITTO20070245A1

Abstract

Tape (10) and biadhesive element (4) of gluing material for joining two parts (2) (3) of an item of footwear, in which a portion of gluing material designed to be inserted between the parts to be joined comprises an intermediate layer (6) and two side layers (7) (8) connected to the intermediate layer (6) and having a density lower than the density of the intermediate layer (6) itself.

Description

BIADHESIVE ELEMENT

TECHNICAL FIELD

The present invention relates to a biadhesive element for joining two parts of an item of footwear.

BACKGROUND ART

In the field of production of footwear it is known from the Italian patent application No. UD2006A000170, which is filed in the name of the present applicant and is entirely- incorporated herein for completeness of description and as regards the necessary parts, for connecting two elements of an item of footwear, for example, an innersole to a sole or else a sole to an upper, using an element of adhesive material, which, conveniently, is first coupled to one of the two parts to be joined and subsequently brought into contact with the other part and forced between the parts themselves to form the join in the complete absence of solvent materials.

For the above purpose, once again known from the aforesaid Italian patent application is the use of an adhesive tape comprising a flexible supporting element in the form of a sheet, and a layer of gluing material spread over the flexible element. The gluing operations envisage transfer of a part of the gluing material present on the flexible element onto one of the two parts to be joined, subsequent removal of the flexible supporting element from the layer of gluing material transferred, and joining of the other part to be joined to the surface of the gluing material left uncovered by the flexible supporting element itself. The gluing material, which at this point is set between the parts to be joined, is squeezed by forcing the parts themselves against one another, thus completing the connection. Adhesive tapes currently used for forming adhesive elements to be set between the parts to be joined, even though they are universally used and are able to provide valid joins between the majority of the parts to be joined, present characteristics of embodiment such that it is not possible to increase the adhesiveness of the gluing material beyond preset limits. As is known, in fact, adhesiveness is strictly correlated to the viscosity and to the density of the gluing material in so far as the more fluid a gluing material is, the higher its capacity of penetration and, hence, of interaction with the parts to be joined following upon compression of the parts themselves. On the other hand, however, the more fluid the gluing material is and/or the lower its density, the lower the degree of cohesion of the material and hence the more difficult it is to displace or manipulate the gluing material itself. In the specific case, it becomes increasingly problematical to detach the gluing material from the sheet support without there being formed smears or filaments, which would jeopardize, in the last resort, the quality of the end product .

For this reason, in known adhesive tapes, the viscosity and the density of the gluing material are a consequence of a compromise imposed between adhesion and cohesion.

DISCLOSURE OF INVENTION

The aim of the^' present invention is to provide a biadhesive element that will enable a simple and inexpensive solution to the problems set forth above .

According to the present invention, a biadhesive element of gluing material is provided for joining two parts of an item of footwear, said element being characterized in that it comprises an intermediate layer of gluing material and two side layers of gluing material connected to said intermediate layer; said intermediate layer having a higher density than the side layers.

Conveniently, in the biadhesive element defined above, the density of the intermediate layer may range between 750 and 850 kg/m³ , whilst, preferably, the density of the side layers may range between 130 and 250 kg/m³.

The present invention moreover relates to a tape for providing a biadhesive element to be set between the parts to be joined.

According to the present invention, an adhesive tape is provided for forming biadhesive elements for connecting two parts of an item of footwear, the tape comprising an elongated flexible support of sheet material, and a gluing material spread over said flexible support of sheet material; said tape being characterized in that said gluing material comprises an intermediate layer of gluing material and two side layers of gluing material connected to said intermediate layer, one of said side layers of gluing material being connected to said support of sheet material, said intermediate layer having a higher density than the side layers.

Conveniently, in the adhesive tape defined above the gluing material comprises a plurality of intermediate portions, which are each designed to define a corresponding biadhesive element as claimed in any one of Claims 2 to 10.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the attached figures, which illustrate a non-limiting example of embodiment thereof, and where :

Figure 1 illustrates, in cross section, a biadhesive element of gluing material provided according to the teachings of the present invention inserted between two parts to be joined of an item of footwear; Figure 2 is a schematic illustration in side elevation, with parts removed for reasons of clarity, of a succession of steps for producing a continuous adhesive tape for forming the biadhesive elements of Figure 1;

Figure 3 is a schematic illustration in plan view of a part to be joined of the item of footwear set on top of the tape formed in the production plant illustrated in Figure 2; and

Figure 4 is a schematic cross section of one of the parts to be joined with the biadhesive element of gluing material of Figure 1 connected thereto.

BEST MODE FOR CARRYING OUT THE INVENTION

In Figure 1, designated as a whole by 1 is an item of footwear comprising a first portion 2 constituted, for example, by a sole or by an innersole, and a second portion 3 constituted, for example, by an upper or by the sole itself.

The portions 2 and 3 are stably connected to one another without the use of solvent materials via a shaped biadhesive element 4 of gluing material set between the portions 2 and 3 and squeezed following upon pressing of the portions 2 and 3 themselves against one another.

The biadhesive element 4 is made only of gluing material and comprises an intermediate layer 6 of gluing material and two side layers 7 and 8, once again of gluing material, connected to the intermediate layer 6. The intermediate layer 6 has a higher density than the side layers 7 and 8 and, preferably, can range between 750 and 850 kg/m³, whilst the side layers 7 and 8 have a density that can range between 130 and 250 kg/m³. Conveniently, the side layers 7 and 8 have comparable or exactly the same density. Alternatively, the side layers 7 and 8 have respective densities that differ from one another, for example, so that each of them will adapt to the characteristics of construction of the part of the item of footwear with which they come into contact .

Preferably, moreover, both the gluing material of the intermediate layer 6 and that of the side layers 7 and 8 comprises one or more photosensitive acrylic resins or acrylic resins in aqueous dispersion.

According to the invention, the intermediate layer 6 has a thickness Si greater than the thicknesses Sl of the side layers and, conveniently, ranging between 0.3 and 0.5 mm, whilst the side layers 7 and 8 have a thickness ranging between 0.15 and 0.20 mm. The large thickness of the intermediate layer as compared to that of the side layers favours detachment and increases definition of the profile.

In the particular example described, the biadhesive element 4 is obtained starting from a multilayer tape 10 (Figure 2) , which, once again according to what is illustrated in Figure 1, comprises a tape support 11 of plastic or paper material, preferably siliconed paper or other equivalent material with low adhesiveness, which has, advantageously, an adhesiveness lower than the adhesiveness of the side parts 7 and 8 to be joined and forms part of a reel 13 to be unwound carried by a fixed support (not illustrated) .

The tape support 11 is unwound off the reel 13 by an unwinding assembly (not illustrated) , and advances along a rectilinear path 15 above a resting plane P between an input station 16 and an output station 18 (Figure 3) and through two intermediate stations designated, respectively, by 19 and 20.

In the input station 16, via a dispenser assembly 22, spread over the surface 23 of the tape support 11 facing upwards is a continuous layer 25 of gluing material having the same characteristics and the same thickness as those of the side layer 7. Between the station 16 and the station 19 the layer 25 of material deposited is fed through a polymerization device, designated by 26, and, conveniently, of the UV type.

Once again with reference to Figure 2, during transit of the layer 25 through the station 19, superimposed on the layer 25 itself and connected thereto is a further continuous adhesive layer 27 having the same characteristics and the same thickness as the intermediate layer 6. For said purpose, the station 19 houses a dispenser and feed assembly 28, comprising a motor-driven belt conveyor 29, which in turn comprises a belt 30 run over a leading roller 31 and a trailing roller 32. The rollers 31 and 32 are able to turn about respective fixed hinge axes 33 parallel to the plane P and are set at a height from the plane P such that a return branch 35 that extends in a position that faces and is parallel to the plane P is set at a distance from the plane P itself approximating by defect the thickness of the layers 25 and 27. The assembly 28 then comprises a dispenser device 36 set above a delivery branch 37 of the belt 30 to form on the delivery branch 37 itself the layer 27 of material, and a polymerization device, designated by 39, and, conveniently, of the UV type, set downstream of the dispenser device 36 in the direction of feed of the layer 27.

In the station 19, as a result of the conveyor 29, the two layers 25 and 27 are stably connected to one another, after which they advance, in conjunction with the tape support 11, on the surface of the plane P traversing the station 20. Housed in the station 20 is a further dispenser and feed assembly 40 similar to the assembly 28 for forming and feeding through the station 20 itself a further continuous adhesive layer 41 having the same characteristics and the same thickness as the intermediate layer 8. The assembly 40 comprises a motor-driven belt conveyor 42, which in turn comprises a belt 43 run over a leading roller 44 and a trailing roller 45. The rollers 44 and 45 are able to turn about respective fixed hinge axes 46 parallel to the plane P and are set at a height from the plane P such that a return branch 47 that extends in a position that faces and is parallel to the plane P is set at a distance from the plane P itself approximating by defect the thickness of the layers 25, 27 and 41. The continuous layer 41 is formed by a dispenser device 50, which forms part of the assembly 40, and is set above a delivery branch 51 of the belt 43 downstream of a polymerization device, designated by 52, and, conveniently, of the UV type.

The conveyor 42 feeds the layer 41 in contact with the underlying layer 27 and, with its return branch 47, forces the layer 41 against the layer 27, joining them stably together to form the tape 10.

At this point, the tape 10 advances towards the output station 18, in which the part 3 to be joined is set on the free surface of the layer 8, 41 and forced against the latter as described in the patent application No. UD2006A000170 referred to above and illustrated in Figure.3, thus joining the part 3 stably to the layer 41. Once again during feed of the tape support 11, the gluing material left uncovered by the part 3 of the item of footwear is completely removed from the support 11 itself, after which, the part 3 and the underlying gluing material are detached from the tape support 11 so as to form the layered biadhesive element 4, which has exactly the same shape or perimeter as the part 3 itself, as may be seen in Figures 3 and 4. Next, the biadhesive element 4 is superimposed on the part 2 to be joined and stably connected to the part 2 itself, thus providing a stable join between the parts 2 and 3 of the item of footwear.

Alternatively, according to a variant (not illustrated) , instead of being fed through the station 18, the tape 10 is deviated towards a cutting station, in which the tape 10 itself is cut in a transverse direction to form a plurality of shaped biadhesive elements 4, partially coated with the corresponding part of the sheet support 11, which is removed before setting the biadhesive element between the parts 2 and 3 to be joined together.

From the foregoing description it is clear that the biadhesive element 4 described, since it is of the layered-gluing- material type, not only enables avoidance of the use of solvent materials in the process of joining of the various parts of the item of footwear but also enables a stable and long-lasting connection irrespective of the material and the characteristics of the parts to be joined together.

In fact, the use of layered gluing materials with three layers enables, on the one hand, an element of gluing material to be obtained having the cohesiveness necessary for the required handling thereof but, above all, precise detachment, along pre-set lines and without smears or deformations of the gluing material from the forming supports envisaged, such as, for example, the sheet support of the solution described. On the other hand, the element 4 of gluing material has an excellent adhesiveness owing to the fact that the outer layers have contained densities and hence a high level of fluidity and consequently a capacity for setting themselves between the parts to be joined and penetrate the gasps and partially the structure of the parts to be joined themselves, thus providing a resistant join without any smears.

From the foregoing description it emerges clearly that modifications and variations can be made to the element 4 and to the tape 10 described herein, without thereby departing from the sphere of protection defined by the annexed claims. In particular, both the element 4 and the tape 10 could comprise a number of layers different from the one indicated purely by way of example. In particular, the side layers 7 and 8 that come directly into contact with the parts to be joined might not be connected directly to the intermediate layer 6 but via interposition of interface layers once again made up of gluing material but having a density different from that of the layers with which they are in contact.

Claims

C L A I M S

1. A biadhesive element of gluing material for joining two parts of an item of footwear, characterized in that it comprises an intermediate layer of gluing material and two side layers of gluing material connected to said intermediate layer; said intermediate layer having a higher density than the side layers .

2. The element according to Claim 1, characterized in that the density of the intermediate layer may range between 750 and 850 kg/m³.

3. The element according to Claim 1 or Claim 2, characterized in that the density of the side layers may range between 130 and 250 kg/m³.

4. The element according to any one of the preceding claims, characterized in that said side layers have comparable densities .

5. The element according to any one of Claims 1 to 3, characterized in that said side layers have respective densities that differ from one another.

6. The element according to any one of the preceding claims, characterized in that said intermediate and side layers comprise at least one acrylic resin.

7. The element according to Claim 6, characterized in that said acrylic resin is a photosensitive resin.

8. The element according to Claim 6, characterized in that said acrylic resin is a resin in aqueous dispersion.

9. The element according to any one of the preceding claims, characterized in that said intermediate layer has a thickness greater than the thickness of said two side layers.

10. The element according to any one of the preceding claims, characterized in that said intermediate layer has a thickness ranging between 0.3 and 0.5 mm and the side layers have a thickness ranging between 0.15 and 0.20 mm.

11. An adhesive tape for forming biadhesive elements for connection of two parts of an item of footwear, the tape comprising an elongated flexible support of sheet material, and a gluing material spread on said flexible support of sheet material; said adhesive tape being characterized in that said gluing material comprises an intermediate layer of gluing material and two side layers of gluing material connected to said intermediate layer; one of said side layers of gluing material being connected to said support of sheet material; said intermediate layer having a higher density than the side layers .

12. The tape according to Claim 11, characterized in that said gluing material comprises a plurality of intermediate portions, each designed to define a corresponding biadhesive element as claimed in any one of Claims 2 to 10.

13. Use of a biadhesive element of gluing material for joining two parts of an item of footwear, the gluing material comprising an intermediate layer of gluing material and two side layers of gluing material connected to said intermediate layer; said intermediate layer having a higher density than the side layers .