EP1753316A1

EP1753316A1 - Film comprising individual anchored filaments

Info

Publication number: EP1753316A1
Application number: EP05773071A
Authority: EP
Inventors: Jean-Pierre Ducauchuis
Original assignee: Aplix SA
Current assignee: Aplix SA
Priority date: 2004-05-21
Filing date: 2005-05-20
Publication date: 2007-02-21
Also published as: FR2870436B1; CA2563591A1; US7727611B2; WO2005122816A1; JP2007537810A; FR2870436A1; CN1972609A; US20070233023A1; KR20070032659A; BRPI0510405A; MXPA06013363A

Abstract

The invention relates to a film comprising individual anchored filaments. More specifically, the invention relates to the female part of a hook-and-loop self-adhering support, comprising a plastic film and indentpendent filaments which are fixed to one of the faces of the film. The invention is characterised in that part of the length of each filament is anchored to the plastic film, while the remainder thereof is disposed at a distance from the film, such as to form loops. According to the invention, the film is made from a non-elastic and non-heat-shrinkable material and the filaments have a count of less than 10, preferably less than or equal to 7.7, for example between 2 and 5 decitex.

Description

ANCHORED INDIVIDUAL FILAMENT FILM

The present invention relates to a female part with loops for a hook-and-loop fastening device with hooks and loops, in particular for use for the closure of diapers. The present invention also relates to a method of manufacturing a female part with such loops. Many devices and methods are described in the patent literature concerning these female parts with loops for hook-and-loop fasteners and in particular in the field of diapers. Given the production requirements, we want to be able to have a female part with loops as inexpensive as possible and to be able to manufacture it with the fastest possible production rate. It is known for example from European patent No. 0 289 198, in the name of the company Procter & Gamble Company, a female part with loops consisting of a film or film of elastic material and of filaments welded to the film in a pattern of welding, the welding being carried out so that loops are formed by the filaments between them and the film. To do this, it is necessary to provide a film of an elastic, or even heat-shrinkable, material. The manufacturing process for these female parts is complicated to implement, in particular due to the fact that there is provided a welding step and a step of shrinking the film to form the loops. Thus, the female part obtained is particularly expensive. Indeed, an elastic material (let's not even speak of a heat-shrinkable material) is an expensive material on the one hand and on the other hand the filaments, to support the various operations (welding and drawing), are filaments of large diameters , especially greater than 10 Décitex, hence a high cost. The present invention relates to a method of manufacturing a female hook-and-loop fastener which makes it possible to obtain a female hook-and-loop fastener at very low cost on the one hand and which allows high-speed manufacturing thereof on the other hand. In addition, the use of fine filaments also allows a very soft feel, since the filament being extruded, it is in a state of material with low orientation, which leaves a great flexibility and softness. We also get a good readability of the drawings which could be printed below the film. According to the invention, the method of manufacturing a female hook-and-loop part, comprising a plastic film and filaments fixed on one of the faces of the film to form loops, is characterized in that it comprises the steps which consist : - forming by extrusion a plastic film; - passing a curtain of filaments between a belt or a pressing roller and a forming roller so as to give each filament a hollow and bump shape; - Bringing the hollow filaments and bumps in contact with the softened plastic material of the film, at the extrusion outlet, on the surface thereof, by application of an electrostatic field to anchor, by electrostatic pressure, the filaments in the material of the softened plastic film, so that the bossed parts of the filaments form the loops while the hollow parts are anchored in the plastic. The manufacturing process is therefore particularly rapid and allows large-scale production of female parts with loops for hook-and-loop fasteners, in particular in the field of diapers. Preferably, according to a preferred embodiment, the filaments have a titer less than 10 decitex and in particular less than 7.7 decitex, in particular between 2.2 and 5.5 decitex. Preferably, the plastic film has a thickness of between 10 and 20 μm or 30 μm, when it is to be printed, and between 5 and 15 μm without printing. According to a preferred embodiment of the invention, the plastic film is a material which is not elastic at least in the direction of the filaments (direction of travel of the film) and not heat-shrinkable. By elastic material is meant a material, which substantially resumes its initial shape without deformation (that is to say in particular that it returns to a shape having a dimension less than 105% of its initial dimension) when it undergoes elongation in a any direction greater than 120% of its initial dimension in said any direction at rest. The term “material which is not heat shrinkable” means a material which, when subjected to heat, does not shrink by more than 10%, in particular when it is subjected to an equal or higher, at 140 ° for at least 10 seconds. The present invention also relates to a female part with loops for hook-and-loop fastener closure, in particular for a diaper, obtained by the process according to the invention. According to the invention, the female part, consisting of a plastic film and filaments, independent of each other and fixed on one of the faces of the film, is characterized in that each filament is anchored on a part of its length in the plastic film, while on other parts, it is at a distance from the film to form the loops; - The film being, at least in the longitudinal direction of the filaments, in a non-elastic and non-heat-shrinkable material, and the parts forming loops of the filaments are independent of each other. In the present invention, by filaments or parts of loops of filaments which are independent of one another is meant filaments, or parts of loops of filaments, which are not linked to their neighbor ( e) s, for example by forming a sheet. According to the present invention the filaments are connected to each other by the plastic film only and not to each other directly, even if it may happen in the final product that certain filaments come into contact with others at the level of the parts forming loops. However, there is no fixation at this contact and the filaments can move away from each other by themselves, contrary to the case where they are formed into a sheet. According to an improvement, - the filaments have a titer of less than 10 decitex, preferably less than or equal to 7.7, in particular between 2.2 and 5.5 decitex. According to a preferred embodiment of the invention, the loops protrude from the film with their feet arranged in rows, the rows being spaced from each other by an inter-row distance at least equal to 0.05 mm, in particular greater than or equal to 0.15 mm. According to a preferred embodiment, the filaments are arranged on the film in a single layer, that is to say each filament is alone above the film without another filament on top. Preferably, the film has a thickness of between 10 and 20 or 30 μm, when it is to be printed, and between 5 and 15 μm without printing. According to an advantageous embodiment, the filaments are multi-lobed, in particular three-lobed or four-lobed, the non-round section in the shape of a clover with several sheets making less yarn material necessary for simultaneously a higher coating of the filaments in the film. According to an advantageous embodiment, the filaments are crimped or textured, thus favoring the grip of the hooks due to the local undulation on the outer surface of the filaments themselves. Each filament thus crimped or textured is more easily distinguished from its neighbors. By way of illustration only, an embodiment of a method according to the invention and of a loop part obtained by a method according to the invention will now be described, with reference to the drawings, in which: FIG. 1 is an overview of a device for implementing the manufacturing method according to the invention; Figure 2 is a perspective view of a loop portion according to the invention. Figure 3 shows part of the device of Figure 1 on a larger scale. FIGS. 4a and 4b are views on a larger scale of parts of the forming roller and the toothed belt of the device of FIGS. 1 and 3. In FIG. 2, one can see a part with loops according to the invention. This loop part consists of a film 1 of non-elastic and non-heat-shrinkable plastic material, filaments 2 being anchored in the film 1. The filaments 2 are arranged in rows on the film 1. Each filament 2 consists of a succession of hollow and bump parts, namely hollow or anchor parts 3 and parts in bumps or loops 4. In the anchor parts 3, the filaments are anchored in the plastic of the film. In particular, they are partially anchored in the plastic of the film. The filaments have a titer equal to 5.5 decitex. Preferably, this titer is strictly less than 10 decitex. Each row of loops in the longitudinal direction in the figure is spaced from the neighboring rows by a distance equal to and preferably greater than 0.15 mm, in particular between 0.05 and 0.5 mm. This inter-row distance can vary from one row to another, in particular to avoid an overly pronounced lineage effect. In the figure, the loops are shown well aligned in a row. In fact, it usually happens that the loops tilt to one side or the other and then come into contact with a loop of a neighboring row. Consequently, a more precise definition of a row consists in taking into account only the legs of the loops which are always aligned in rows. The anchoring parts 3 extend over a length of, for example, between 0.2 and 1.5 mm, for example 0.8 mm, the loops have a length of, for example, between 0.5 mm and 2.5 mm , for example 1.6 mm, their height being approximately 1 mm, possibly being between for example 0.2 mm and 1.5 mm. The plastic material of the film, which may be one-layer or multilayer, may be a polyolefin such as polypropylene or polyethylene (temperature at the outlet of the die higher than the softening temperature generally between 120 ° C and 180 ° C), a polyamide or a polyester (temperature at the outlet of the die greater than the softening temperature between 180 ° C and 270 ° C), or a modified copolymer (temperature at the outlet of the die greater than the softening temperature between 80 ° C and 180 ° C) while the filaments can be for example polyamide, polyester or polypropylene. The film can also be formed in multiple layers. The process for manufacturing a loop part as shown in FIG. 2 is as follows: firstly, a softened plastic film is extruded from an extrusion die 10 which is circulated to a speed equal to 300 m / min preferably between 200 and 500 m / min On the other hand, a curtain 30 of filaments is extruded from a die

31 and is made to pass between a forming roller 40 and a toothed belt (or roller). The forming roller 40 is grooved. The notched belt 50 has grooves 51 of complementary shapes of ribs 41 formed on the outer surface of the roller 40. Likewise between the grooves 51, studs 52 of complementary shapes of recesses 42 are formed formed between the ribs 41. Au bottom of the recesses 42, there are provided suction holes 43 allowing the filaments of the curtain 30 passing between the roller 40 and the belt 50 to be pressed by suction. Thus, when the filament is pressed between the 40. forming roller and the notched belt 50, it undergoes a deformation so as to be gathered by being caught between the recesses 42 and the pads 52 complementary. At the exit of the forming roller and the belt, the filaments have hollow and bump shapes. The curtain of hollow and bump filaments is then brought into contact with the softened plastic film directly at the outlet of the plastic film extrusion. An electrostatic device (electrostatic bar 60) of the Eltex type applies an electric field at the location of this contact between the filaments and the softened plastic film. This electrostatic field, which depends on the unwinding speed and which in particular can be between 200 and 500 V / m allows the application of an electrostatic pressure which anchors the hollow parts of the filaments in the plastic film which is still softened, leaving the bumpy parts away from the film, so as to obtain a female part at the exit from the zone of the electrostatic field as shown in FIG. 2. Once the film-filament contact has been made at the extrusion outlet, the cooling very fast plastic material anchors the filaments in the film. In the case of a film with a layer, for example made of polypropylene, the temperature of the film depositing on the filaments, for example also made of polypropylene, is of the order of 150 ° C. This temperature is higher than the softening temperature of polypropylene. In the case of a multilayer film, for example a first layer of polypropylene and a second layer of modified copolymer, the first layer is at a temperature of 150 ° C. and supports the second layer which is at a temperature above its point of melting (for example beyond 130 ° C.), the second layer having the function of being a bonding layer with filaments of different material, for example made of polyamide, which makes it possible to carry out all the possible combinations for the materials of the film and filaments. This manufacturing process is particularly simple and quick. The product obtained is particularly inexpensive since the film can be produced from a simple plastic material, which is neither elastic nor heat-shrinkable and the filaments need not be thick and in particular the titles are strictly less than 10 decitex and preferably less than or equal to 7.7 decitex, in particular between 2.2 and 5.5 decitex. The female part obtained is thus particularly suitable for use in diapers where it is necessary to produce female parts in large quantities and at the lowest possible cost.

Claims

1. Female part, consisting of a plastic film and filaments, independent of each other and fixed on one of the faces of the film, characterized in that each filament is anchored over part of its length in the film in plastic, while on other parts, it is spaced from the film to form the loops; the film being, at least in the longitudinal direction of the filaments, a non-elastic and non-heat-shrinkable material, and the parts forming loops of the filaments are independent of each other.

2. Female part according to claim 1, characterized in that the filaments have a titer less than 10 decitex, preferably less than or equal to 7.7 decitex, in particular between 2.2 and 5.5 decitex.

3. Female part according to claim 1 or 2, characterized in that the loops protrude from the film being arranged in rows, the rows being spaced from each other by an inter-row distance at least equal to 0.05 mm, in particular greater than or equal to 0.15 mm.

4. Female part according to claim 1, 2 or 3, characterized in that the filaments are arranged on the film in a single layer, that is to say each filament is alone above the film without another filament on top.

5. Female part according to one of claims 1 to 4, characterized in that the film has a thickness of between 10 and 20 or 30 μm, when it is to be printed, and between 5 and 15 μm without printing.

6. Female part according to one of claims 1 to 5, characterized in that the anchoring parts (3) extend over a length of between 0.2 and 1.5 mm, for example 0.8 mm, the loops have a length of between 0.5 mm and 2.5 mm, for example 1.6 mm, their height being approximately 1 mm.

7. Female part according to one of claims 1 to 6, characterized in that the filaments are crimped or textured.

8. Female part according to one of claims 1 to 7, characterized in that the filaments are multilobed, in particular trilobed or quadrilobed.

9. A method of manufacturing a female hook-and-loop part according to one of the preceding claims, comprising a plastic film and filaments independent of each other fixed on one of the faces of the film to form loops, characterized in that 'It comprises the stages which consist in: - forming by extrusion a plastic film; - passing a curtain of filaments between a belt or a pressing roller and a forming roller so as to give each filament a hollow and bump shape; - Bringing the hollow filaments and bumps in contact with the softened plastic material of the film, at the extrusion outlet, on the surface thereof, by application of an electrostatic field to anchor, by electrostatic pressure, the filaments in the material of the softened plastic film, so that the bossed parts of the filaments form the loops while the hollow parts are anchored in the plastic.

10. Method according to claim 9, characterized in that the filaments have a titer less than 10 decitex and in particular less than 7.7 decitex, in particular between 2.2 and 5.5 decitex.

11. Method according to claim 9 or 10, characterized in that the plastic film is a non-elastic and non-heat-shrinkable material.

12. The method of claim 9, 10 or 11, characterized in that a curtain (30) of filament is extruded from a die (31) and is caused to pass between a forming roller (40) and a belt or a notched roller, the forming roller (40) being a groove and the notched belt or roller (50) comprising grooves (51) of complementary shapes of ribs (41) formed on the external surface of the roller (40), studs (52 ) of complementary forms of recesses (42) formed between the ribs (41) being formed between the grooves (51) at the bottom of the recesses (42), there are provided suction holes (43) making it possible to press the curtain filaments (30) passing between the roller (40) and the belt (50).

13. Diaper comprising a female part according to one of claims 1 to 8.