MXPA00012772A - Method and device for fixing pieces of material on a continuous web - Google Patents

Abstract

The invention relates to a device and a method for producing a material laminate (1) by fixing pieces of material (2) at a given distance from one another on a first continuously advanced material web (4). The invention is characterized in that the pieces of material (2) are cut from a second continuous material web (7) in afirst station (3) and are conveyed via a transport device (10) to the first web (4), to which the piece of material (2) is attached by means of ultrasonic welding over a limited attachment area (5) on the pieces of material (2), and the pieces of material (2) are subsequently fixed on the material web (4) by ultrasonic welding in a second station (6). The second station comprises an ultrasonic horn (18) at a fixed distance from a stay (19) designed as a rotating drum with a patterned outer surface.

Description

METHOD AND DEVICE FOR FIXING PIECES OF MATERIAL IN A CONTINUOUS FABRIC TECHNICAL FIELD The present invention relates to a method and a device for fixing fibrous pieces of material made from a porous and elastic material at a given distance between them in one or several Continually advancing material fabrics and, to join them, the establishment of an optional pattern on the piece of material, preferably for the production of a layered material for use in absorbent products. The absorbent products may consist of diapers, baby breeches, incontinence briefs, sanitary napkins, calf lining and the like. The invention can also be used in other areas in which one or more shorter pieces of material must be fixed on one or more continuous fabrics. BACKGROUND OF THE INVENTION It is already known to fix pieces of material in a fabric by means of glue. The glue process has considerable disadvantages, for example, the handling of additional material which also involves undesirable costs. Other disadvantages in the process by the use of glue are that the glue residues are deposited in inappropriate places in the equipment and therefore create problems, and also that the use of glue involves additional cost, and the glue layers in a product in layers of liquid transporting material affect the prerequisites for the flow of liquid. It is also known to join one or more continuous tissues together through ultrasound. This is disclosed, for example, in WO 97/23340 which discloses the use of ultrasonic horns in combination with rotating tensioners for joining continuous fabrics together in a given pattern, where the purpose of the pattern is to make possible an intermittent joining of two. or more continuous tissues. This known arrangement is not suitable for fixing short pieces of material on a continuous fabric. The object of the present invention and its most important characteristics The object of the present invention is to solve the problems associated with the techniques indicated above and to make possible the use of ultrasonic welding to fix pieces of material on a continuous fabric. Above all, the invention makes possible quick, inexpensive and simple adjustments to adapt to changed circumstances, for example, a change of material or the exchange of various parts of the equipment, and adjustments in case of pattern exchange. In addition, the invention results in short stoppages of operation for service and maintenance.

In accordance with the present invention, this is achieved on the one hand by a method in which each piece of material is fixed on a continuous fabric through ultrasound in a first station, after which the piece of material is fixed on its surface. whole contact surface through ultrasound in a second station, and on the other hand by a device consisting of a first station to hold the piece of material on the continuous fabric and a second station in which the piece of material is fixed on its entire surface over the continuous tissue.

The invention results in the advantages that the material can be produced without the use of glue and therefore the costs and service requirements are reduced. The invention also offers the advantage that, through a continuous supply of energy to the ultrasonic horns, pieces of material are fixed on a continuous fabric and at the same time a pattern according to what is described is obtained, for example, in the Application Patent SE 9801038-2. DESCRIPTION OF THE DRAWINGS Figure 1 shows a side view of a processing equipment according to a first embodiment of the invention. Figure 2 shows a side view of a first welding station in the processing equipment according to Figure 1.

Figure 3 shows a perspective diagram of a second welding station in the processing equipment according to Figure 1, and Figure 4 shows a second embodiment of the first welding station with a combined drum for a tensioner during cutting and transport. The invention is not limited to the details of the device and method described below, nor to that illustrated in FIGS. 1. DESCRIPTION OF THE MODALITIES FIG. 1 illustrates a processing equipment in accordance with one embodiment of the present invention for the production of a layered material 1, wherein a piece of material 2 is placed in a first station 3 in the desired position in a first fabric of continuous material 4 and is held in this position by ultrasonic welding in a pattern within at least one area 5 that covers a part of the contact surface of the piece of material 2 against the fabric of material 4, and is subsequently fixed on the fabric of material 4 through ultrasonic welding in a second station 6 with a pattern that covers essentially the entire contact surface against the fabric of material, by means of which a layered material 1 is formed for use in absorbent products s. The continuous first continuous web 4 can, for example, constitute an outer layer in an absorbent product and usually consists of a thin nonwoven material. The first material web 4 may consist of a non-woven material containing at least 5% thermoplastic fibers, usually more than 40% thermoplastic fibers. All thermoplastic fibers commonly used in this field that can be softened and / or fused when subjected to ultrasonic energy can be employed in the invention described herein. The first fabric of material 4 that is fed to the machine may consist of a prefabricated material and may be produced by several different methods, for example by carding or spinning a fiber fabric subsequently bonded with a binder. What is known as a meltblowing technique can also be used for the purpose of applying short fibers in the form of a fiber mat. Components that melt with application of heat in the material can also be used for bonding by means of ultrasound. The material fabric 4 may also consist of a composite nonwoven material. The substance of the material in the first fabric of material 4 for use in accordance with the present invention is usually between 10 and 80 g / nr, preferably between 10 and 50 g / pr. The pieces of material 2 are fixed on the fabric of material 4 in the first station 3 at a given distance between them, and are produced from a second fabric of continuous material 7. The material in this fabric may consist of the same material as the material in the first fabric of material 4 or of a different material. The second web of continuous material 7 may consist in the same manner of several fabrics placed one on top of the other and / or two or more, preferably three parallel fabrics with the same material composition or with a different material composition. The material for pieces of material 2 which is especially suitable for use in absorbent products is a filling material with a substance greater than 10 g / pr, preferably between 10 and 250 g / itr or particularly between 20 and 100 g / m ", consisting mainly of elastic fibers and comprising a thermoplastic material or at least a surface structure of thermoplastic material The second continuous material web 7 is fed continuously by feed rollers 8 at a feed rate that can be regulated in a conventional manner, through which the fabric of material 7 receives a considerably reduced feed rate relative to the first fabric of continuous material 4. By suitable selection of the feeding speed of the second fabric of material 7 and the synchronization of cutting units 9, the distance between pieces of material 2 when placed in the first fabric of material 4 can be defined. When the material in the second fabric 7 of continuous material has been advanced by the feed rollers 8 to a given length, it is placed in the transport drum 10 over a part of the length of a piece of material 2. By creating a negative pressure in the transport drum, suction is generated through holes 11 in the external surface of the transport drum 10, said suction ensures the continuous transport of the second continuous material fabric 7 after the feed rollers 8. When the given length of the piece of material has been advanced, the fabric of material is cut by a cutting unit 9 with a cutting tool in the form of a cutting roller 12 which interacts with a fixed or rotary tensioner 13 after which the speed of transport of the piece of material 2 produced rises to the speed constituting the peripheral speed of the transport drum, which corresponds essentially to the speed of The first continuous woven fabric 4. Through clamping devices, easily interchangeable jaws 14 are mounted on the transport drum 10. These jaws are preferably made of a different type of material with superior properties of wear resistance and strength than the material in the rest of the external surface of the transport drum. The jaws 14 can be advantageously made of metal, preferably hardened steel. The number of jaws 14 in the drum 10 can be one or more and depends, among other things, on the interrelation between the length of the pieces of material 2 and the diameter of the drum 10. The raised part of the pattern in the tensioner jaws 14 establishes joining points when the piece of material 2 is fastened on the fabric of material 4. The flexibility and softness of the material are retained to a large extent when the points of attachment represent 2 to 20% of the fixing area. The jaws 14 are provided with a suitable raised pattern and also with several through holes, through which the negative pressure of the drum sucks the first end 15 of the piece of material 2 firmly against the jaw 14. The through holes in the jaws 14 they are located in suitable positions relative to the pattern selected on this side of the jaw that constitutes a part of the periphery of the transport drum 10, while the holes in said periphery are independent of both the pattern defined at the time of welding by means of ultrasonic energy as the thickness of material and its magnitude in the transverse direction of manufacture. The pattern depth of the jaws 14 for the manufacture of material for absorbent products suitably vary between 0.3 mm and 1.5 mm and preferably from 0.5 to 1.0 mm in the case of a thin material with a thickness between 0.2 mm and 2.0 mm. The jaws 14 in the transport drum 10 are positioned in such a way that the radius R 'from the center of the drum towards the pattern surface of the jaw is greater than the radius R "from said center toward the outer surface of the drum. Recommended magnitude of the difference (R'-R ") can be expressed as (R'-R") 1.5 x the thickness of the layered material 1. The synchronization between the positions of the cutting roller 12 and the transport drum 10 at the time of the cut is selected in such a way that the piece of material 2, when cutting in the cutting station 9, does not completely cover the jaw 14 on its extension in the machine direction, as can be seen from the figure 2, and provides the great advantage that the requirement of precise control of the cutting roller 12 is reduced.

The pattern surface 16 of the jaw 14 has an extension, in the transverse direction of the machine, that exceeds the width of the area 5 finally joined between the pieces of material 2 and the continuous weave 4, which reduces to a certain extent the requirement of an accurate guide of the material around an imaginary longitudinal axis in the direction of the machine. The peripheral speed of the transport drum 10 corresponds essentially to the linear speed of the material web 4 when the two materials 2, 4 are joined. The fixing of the piece of material 2 on the fabric 4 is effected through the ultrasonic energy generated by an ultrasonic horn 17 placed on the other side of the fabric of material 4 relative to the transport drum 10 with the jaws 14 that constitute a tensioner for the ultrasonic horn 17 that is fed continuously with energy. The prerequisite for fastening the first end 15 of the piece of material 2 on the material fabric 4 according to the present invention can be defined by the following parameters: Thickness of the first fabric of material 4 = A Thickness of the second fabric of material 7 = B Distance between the ultrasonic horn 17 and = C the tensioner / jaw 14 Width of the second fabric of material 7 = D Width smaller of the jaw 14, or = E width of the ultrasonic horn 17 the width of the jaw 14 is constituted by its extension in the transverse direction of the device. Extension of the clamp 14 in the direction = F of the machine Extension of the clamping area 5 in the = G direction of the machine Using the definitions presented above, the following applies: A + B > C F > G D < E When the piece of material 2 is clamped on the web of continuous material 4 at one or several places over a part of its length, it is transported together with the material fabric 4 towards the second station 6. This second station includes a second horn ultrasonic 18 and a tensioner in the form of a roller or drum 19 placed on the opposite side of the fabric. The ultrasonic horn 18 is continuously energized and fixed during operation at a given distance from a tension roller 19. This position is defined in the same manner as described above in relation to the ultrasonic horn in the first station 3. The The pattern in the tensioner 19 constitutes a surface structure on the external surface, wherein the appearance and depth of the pattern are defined based on requirements in relation to the appearance of the final layer material. For material for absorbent products, wherein the first web of continuous material 4 can consist of non-woven fabric with a thickness of less than 0.5 rum, the thickness is preferably within a range of 0.2-0.5 mm, the pieces of material 2 can Consist of filling with a thickness less than 2.0 mm, preferably within a range of 0.5 to 2.0 mm. When materials of the described type are joined together, use is made of a pattern depth of 0.3-2.0 mm, preferably 0.5-1.0 mm. The raised part of the pattern in the tensioner 19 establishes joining points when the piece of material 2 is fastened on the fabric of material 4. The flexibility and softness of the material are conserved to a high degree when the joining points represent from 2 to 20 % of the fixation area. The extension of the pattern in the transverse direction in the tensioner 19 exceeds the width of the material in layers or preferably has a greater width than the piece of material 2, which results in the absence of need for an accurate guide of the material fabric 4 in the cross direction of the machine. The ultrasonic horn 18 does not have to be wider than the patterned part of the tensioner 19. Figure 4 shows a second embodiment characterized in that the cutting roller 12 in the cutting unit 9 works directly against the transport drum.

Claims (17)

1. CLAIMS A method for fixing pieces of material (2) at a given distance between them in a fabric of material (4) that advances continuously, preferably for the production of a layered material (1) for use in an absorbent product, characterized in that each piece of material (2) is in a first station (3) placed in the desired position in the material fabric (4) and is held in this position by ultrasonic welding in a pattern within at least an area (5) that covers a part of the contact surface of the piece of material (2) against the material fabric (4), and is subsequently fixed in the material fabric (4) by ultrasonic welding in a second station ( 6) with a pattern that covers essentially the entire contact surface against the fabric of material (4).
2. A method according to claim 1, characterized in that the pieces of material (2) are fed to the first station (3) in the form of a second continuous fabric (7) that is divided into separate pieces of material (2) in the first station (3), which are placed in the desired position in the first continuous fabric (4).
3. A method according to claim 2, characterized in that the velocity of the second continuous web (7) is set at a speed lower than the speed of the first continuous web (4) in such a way that the desired distance between the web pieces is obtained. material (2).
4. A method according to any of the preceding claims 1-3, characterized in that the ultrasonic welding (5) in the first station (3) and the second station (6) is effected by ultrasonic horns (17, 18) which are continuously fed with energy.
5. A method according to any of claims 1-4, characterized in that the fixing (5) of the piece of material (2) in the first station is made in the front part (5) of the piece of material, when observed in the feeding direction of the first continuous fabric (4).
6. A method according to claim 5, characterized in that the holder (5) has a magnitude in the machine direction of 3 to 24 mm, preferably 5 to 15 mm, from the front edge of the piece of material (2). ).
7. A method according to any of claims 4-6, characterized in that connection points are produced within the clamping area (5) in a pattern in which the connection points represent 2 to 20% of the clamping area.
8. A device for fixing pieces of material (2) at a given distance between them in a fabric of continuously advancing material (4), preferably for the production of a layered material (1) for use in an absorbent product, which it is characterized on the one hand by a first station (3) with an ultrasonic horn (17) placed on one side of the material fabric and a transport and tension device (10) placed on the opposite side of the material fabric (4) and contemplated to place a piece of material (2) in the desired position in the fabric material (4) and hold the piece of material (2) on the material fabric (2) within a limited area (5) in interaction with the ultrasonic horn (17), and on the other hand a second station ( 6) with a second ultrasonic horn (18) on one side of the material fabric and a tensioning device (19) on the opposite side of the material fabric (4), said tensioning device (19) is designed with a patterned surface which faces the fabric of material (4) and has the purpose, in interaction with the second ultrasonic horn (18) of fixing the piece of material (2) on the material fabric (4) with the desired welded pattern that covers essentially the entire contact surface of the piece of material (2) .
9. A device according to claim 8, characterized in that the tensioning device (14) in the first station (3) is mounted on the transport device (10).
10. A device according to any of claims 8-9, characterized in that the transport device and tensioner (10) in the first station (3) comprises a drum with an internal negative pressure and through holes (11) in the external surface.
11. A device according to claim 9, characterized in that the tensioning device (14) in the first station (3) has through holes whose positioning is adapted to the desired clamping pattern, in order to hold the piece of material (2) by means of negative pressure in the drum (10).
12. A device according to any of claims 8-11, characterized in that the first station (3) comprises a cutting unit (9) with a cutting tool (12) and a fixed or rotary tensioner (13) for interaction with the tool.
13. A device according to claim 12, characterized in that the tensioner (13) of the cutting unit (9) is integrated in the transport device and tensioner (10).
14. 14. A device according to any of claims 8-13, characterized in that the tensioner (13) and the ultrasonic horn (17) in the first station (3) have an extension in the feed direction of the fabric of material that is greater than the fastener (5) produced.
15. 15. A device according to any of claims 8-14, characterized in that the tensioner (14) and the ultrasonic horn (17) in the first station (3) have an extension in the transverse direction of the fabric of material that is greater than the extension of the piece of material in this direction.
16. 16. A device according to any of claims 8-15, characterized in that the tensioning device (19) for the ultrasonic horn (18) in the second station (6) consists of a cylindrical drum with an external surface with a continuous pattern . A device according to any of claims 8-16, characterized in that the tensioning device (19) and the ultrasonic horn (18) in the second station (6) have an extension in the transverse direction of the machine that is greater than the extension of the piece of material (2) in the same direction. A device according to any of claims 8-17, characterized in that the pattern depth of the tensioning device (14, 19) in the first station (3) and the second station (6) is within a range of 0.3 to 2.0 mm, preferably 0.5 to 1.0 mm. 10 fifteen J twenty 25