MXPA99004259A - Method and device for producing a hook-and-pile type closure part from thermoplastic plastics - Google Patents

Abstract

The invention concerns a method and device for producing a hook-and-pile type closure part with catching means formed integrally with a support. The catching means are produced by feeding a thermoplastic plastics to the gap between a pressure roller and a shaping roller. The shaping roller comprises a sieve with open cavities produced by etching or by means of laser, such that the finished catching means are produced solely as a result of the fact that the thermoplastic plastics harden at least partially in the open cavities in the shaping roller sieve. Owing to the invention, the shaping roller can be produced very economically, and the hitherto conventional second operating stage when forming the catching means is rendered superfluous.

Description

PROCESS AND DEVICE TO MANUFACTURE A THERMOPLASTIC ADHESIVE CLAMP FIELD OF THE INVENTION The invention relates to a process and device for the manufacture of an adhesive fastener with a multiplicity of locking means designed as a piece with a backrest, in the form of loops with widened areas, into which a thermoplastic is introduced. in the plastic or liquid state within the space between a pressure roller and a forming roller, the forming roller is provided with external and internal openings and both rollers project in opposite directions, so that the backrest is formed in the space between the rollers.

BACKGROUND OF THE INVENTION A process like this is known from the state of the art, in particular from WO 94/23 610 of the Minnesota Mining and Manufacturing Company. In this process, as is also known in the manufacturing process from US-P-3, 270, 408, first needle-shaped bodies are produced whose ends re-form in the form of a mushroom in a second cycle. of operation. The heads of the fungi with the flat head part are known from US-P-3,196,490. The formation of an adhesive fastener for P1113 / 98MX baby diapers or for hospital garments in particular, are described as a potential application for adhesive fasteners produced in this way. Many locking means are required per square centimeter to make it possible to use the adhesive fasteners used in the adhesive fasteners for the type of clothing items mentioned above; this results in very high costs related to the forming roll used in the state of the art to shape the locking means. In order to manufacture the forming roller, it is first necessary to print a number of openings corresponding to the number of locking means, which generates a considerable expense. In addition, a vacuum device must be integrated that executes the function of orienting the loops in the recesses. The forming roller must be cooled to a specific temperature during the operation. In addition to the formation of the loops, a second step in the process is required, which is the formation of fungal heads in the loops oriented by contact with a hot roller. Another disadvantage related to the process of the state of the art is represented by the fact that the location of the squeezing head containing the thermoplastic must be adjusted very much.

P1113 / 98 X Precision so that it is opposite the forming roller in order to obtain a flat backing of very thin thickness as required, for example, for use in adhesive fasteners in baby diapers. That is to say, for example, each repeated loading of the head of the squeezing action mechanism can result in a bad adjustment of the head of the mechanism with squeezing action in relation to the forming roller and thus in the interruption of the production. WO-A-94/29070 describes a forming tool that uses a laser for the manufacture of plastic elements that can incorporate the shape of its surface. The shape is obtained by the openings forming blind holes in a circular cylindrical substrate and the formed occurs as a result of the pressure of a pressure die in the substrate to be formed. The formed elements can also be modified in their form by appropriate subsequent steps following the formed one. US-A-3, 399, 425 discloses a device for forming surfaces of material and, inter alia, for the formation of locking means in the form of loops projecting from a conical tapered backing and in the end further away from the backrest is creased or folded. For this, the device is made of a roller P1113 / 98 X pressure and a forming roller that incorporates a mesh with tapering openings in a conical shape inwards and outwards, the inner surface of the forming roller is operated by a low pressure compared to the outer surface and can be cooled. Based on the state of the art, the object of the present invention is, in accordance with this, to develop a more economical and more effective process for manufacturing the adhesive thermoplastic fasteners, the device required for this purpose, and an adhesive fastener element. or adhesive fastener produced by this process. This objective is achieved with the features described in claim 1. Because the forming roller has a mesh whose recesses or openings produced by water etching, electroplating or laser, it is possible to easily produce a suitable mesh for the forming roller to vary the number of fastening means per square centimeter, since the number of locking means formed is determined by the structure of the mesh. The meshes used in the process are relatively well known in the printing industry. The fact that openings formed by water etching, electroplating or by laser, have a radius extending inward at regular intervals on their perimeters, is used in P1113 / 98MX the process claimed by the invention. During the filling of the openings inwards and outwards, the loops are automatically formed by these spokes, the loops already have widened areas in the shape of a disc. This eliminates the second operation, in which the loops are provided in the state of the art with areas widened downwards in the process. Excessive cooling of the forming roll is also eliminated, since the thermoplastic adhesive fastening elements are removed from the forming roll if the plastic is already hardened to at least some degree. The process claimed by the invention can be carried out relatively with any thermoplastic, preferably polypropylene, polyamide and polyethylene are used, depending on the application. Terpolymers that contain one or more of the named thermoplastics are also suitable. Another advantage of the claimed process for the invention is that the widened areas of the loops can be made in a wide variety of ways at low cost. For example, the widened areas may be designed as mushrooms with concave or flat openings, or they may be in the form of polyhedra ranging from triangles to hexagons. In addition, widened areas in the form of triangles or hexagons may have rounded corners, this increases the likelihood of P1113 / 98MX locked. It is claimed for the invention that it is convenient to manufacture adhesive fasteners with a backing thickness of 0.05 to 0.5 mm and a number of locking means within the order of magnitude of 50 to 400 locking means per square centimeter. Theoretically, it is also possible to prepare thicker backs and they are provided with smaller or greater number of locking means. In one embodiment of the invention, the backing is 0.05 to 0.3 mm, preferably 0.1 to 0.2 mm thick, and is provided with 200 to 400, preferably 300 locking means per square centimeter. The adhesive fasteners produced in this form are used in baby diapers or adult incontinence garments and as carpet fastener elements. In another embodiment of the invention, the backing is 0.1 to 0.5 mm thick, preferably 0.2 to 0.3 mm, and is provided with 20 to 200, preferably 100 locking means per square centimeter. The adhesive fastener element produced in this way is used for abrasive discs, car seats or other applications. The invention also relates to adhesive fasteners that are manufactured by the process claimed for the invention. It also refers to P1113 / 98 X locking means consisting of at least one adhesive fastening element produced by the process claimed for the invention. The invention also relates to the device for the manufacture of an adhesive fastening element, whose forming roll has a mesh with openings produced by water etching, electroplating or by a laser. In a preferred embodiment, the mesh of the forming roller is made entirely of nickel. The protection for the forming roller is also claimed, as claimed for the invention. In the following, the invention is described in detail, with reference to the modalities shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES Figure 1 shows a partial sectional view of the device claimed for the invention for the production of adhesive fastening elements. Figure 2 is a view of a mesh showing part of the openings. Figure 3 is an incomplete cross section of the forming roller claimed for the invention. Figure 3a is an amplified diagram representation of the locking means formed by the P1113 / 98MX openings shown in Figure 3. Figures 4a to 4f show a diagrammatic top view of the forming roller claimed for the invention, with openings of different silhouettes; and Figure 5 is a cross section of an opening with a diagrammatic representation of the formation of an aperture by electroplating, water etching or laser.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a forming roll, indicated as a complete piece by the number 1, in which a mesh 2 consisting entirely of nickel is mounted. The mesh 2 of the forming roller 1 has on its complete circumference the openings 3 that are produced by an electroplating process by the method of the state of the art. These openings can assume a relatively cylindrical base silhouette, as in the case of Figure 1, but by electroplating any other silhouette can be reached whose examples are shown in Figures 4a to 4f. In the embodiment shown, the forming roll 1 has an outer circumference of about 640 mm. In this embodiment, the length of the forming roller 1 is approximately 1,700 mm, however as a principle, these dimensions can be P1113 / 98MX select as required. Because the extensions 5 of the openings are formed where the openings open inwardly and outwardly, the electroplating of the openings 3 results in the typical silhouette as shown by the example of the openings in Figure 3. formation of a radius 23 at the edge of the mesh 2 complements the formation of the extension 5 of the opening. On the left side of Figure 5, there is an opening 3 as it would be without extension 5, while the actual silhouette is shown on the right side. Therefore, the extensions 5 are used to produce the locking means designated as a set 7 of an adhesive fastening element 8 in a single step of the process. For this purpose, a state-of-the-art thermoplastic in a plastic or liquid state is introduced by a feeder device 9 in the form of a squeezing mechanism, into the space 11 between the pressure roller 13 and the forming roller 1. The roller 13 and pressure roller 1 forming rotate in opposite directions, so that the released thermoplastic mechanism squeezed to flow into the space 11 between the roller 13 and pressure roller 1 forming, and in the process within the recesses 3 The thermoplastic present within the space 11 forms a backrest 15 with which P1113 / 98MX joins the locking means 7 to form a part. At the same time, the distance between the pressure roller 13 and the forming roller 1, ie the thickness of the space 11, determines the thickness of the backrest 15. The locking means 7 itself are formed by the flow of the thermoplastic within the open recesses of the mesh of the roller 1 former. Interaction with extensions 5 produced by electroplating as described above, thus results means 7 locked in the recesses 3, whose locking means have a loop formed by the recess 3, an edge 17 widened all its sides in the form of an enlarged area is formed there, at the end of the lacing with a view away from the backrest 15, as illustrated in Figure 3a. This edge 17 is suitable for locking with the locking means of another adhesive fastening element, such as in the form of a cushion, fluff or fibrous canvas. Figure 3a also shows the locking means 7 with thin radius on its perimeter with view away from the backrest 15. These radii are determined by the silhouette of the recesses in the mesh. However, the perimeters of the locking means can be more or less flat. Because the thermoplastic must flow over the extensions 5, facing away from the openings 3 of the mesh 2 of the forming roll 1, the locking means 7 generally has a P1113 / 98 X radius where the loop 16 ends in the backrest 15. The height of the loops can be adjusted as convenient when changing the thickness to that of the mesh 2 mounted on the forming roll 1. If the locking means 7 are formed with flared hexagonal or triangular areas, it is only necessary to form the openings 3 within the triangular or hexagonal silhouette., since the extensions 5 formed correspondingly are formed during the electroplating of the openings 3 at the ends of these openings 3 with outward and inward view. After the thermoplastic has formed both the back 15 and the locking means 7 during flow through the space 11, it is removed from the forming roller 1 as a finished adhesive fastening element 8 by a reverse action mechanism 19 of the state of the art, after 2/3 to 3/4 rotation of the roll 1 former. Both the thermoplastic material used and the thickness of the backing 15, together with the number of locking means 7 per square centimeter, can be determined as convenient as a function of the application of the finished adhesive fastener elements 21. Adhesive fastening elements can be used, for example, for baby diapers or as adult incontinence garments. In this case polypropylene, polyethylene or mixtures of P1113 / 98MX these plastics as the thermoplastic material, since they are economical plastic materials. The thickness of the backing and also the space between the pressure roller 13 and the forming roller 1 is selected from the limits of 0.05 to 0.3 mm, depending on the type of diaper, a backing thickness of 0.2 mm is most often used. The number of locking means 7 per square centimeter is selected in proportion and limits of 100 to 400 locking means 7 per square centimeter, usually 200 locking means 7 per square centimeter are provided. Another area of application of the adhesive fastening elements 8 claimed for the invention is that of the abrasive discs and their like. In this case, the limits for selecting thickness range from 0.1 to 0.5 mm and typically in quantities of 0.2 to 0.3 mm. The number of locking means 7 per square centimeter varies from 50 to 200, and is generally 100 locking means 7 per square centimeter. The openings 3 in the mesh mounted on the forming roller 1 can also be produced by treatment with a laser. With the adhesive fastening element 8 used for the manufacture of abrasive discs or other tools, the quality of the plastic used, and especially its temperature stability, represent an important consideration. For the P1113 / 98 X, therefore, preference is given to a polyamide, especially granulated polyamide or mixtures of thermoplastics with polyamide content. The adhesive fastener elements claimed for the invention can also be used for fastening devices of large areas, such as for carpets and wall hangings, seat covers, packaging materials, wire mesh, and medicinal applications. Adhesive fasteners can be decomposed as they are made of thermoplastic materials subject to deterioration. The adhesive fastener elements claimed for the invention can also be used in other applications where a low cost and / or slim closing device is required.

P1113 / 98 X

Claims (13)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following RE VINDICATIONS is claimed as property: 1. A process for manufacturing an adhesive fastening element with a plurality of locking means designed to be integrated with a backrest, in which a thermoplastic is introduced in a liquid or plastic state within a space between a pressure roller and a forming roller, and the two rollers rotate in opposite directions, so that the backrest is formed in the space between the rollers, wherein the forming roller has a mesh with openings inwards and outwards, and wherein the finished locking means result exclusively from the circumstance that the thermoplastic hardens at least to some degree, in the mesh openings of the forming roller; characterized in that the openings in the mesh are produced by electroplating, etching to the water or by a laser; - the locking means are configured in the form of loops with widened areas; and because the widened areas of the loops are configured as mushroom heads with P1113 / 98 X Concave or flat indentations, or as disk-shaped heads.
2. 2. The process according to claim 1, characterized in that polypropylene, polyamide and a copolymer or terpolymer containing one or more of these plastics are used.
3. 3. The process according to claim 1 or 2, characterized in that the openings in the mesh are in essence of cylindrical silhouette.
4. 4. The process according to any of the Claims 1 or 2, wherein the enlarged of the loops is of triangular or hexagonal silhouette.
5. The process according to Claim 4, wherein the enlarged ones are designed to have rounded corners.
6. The process according to any of Claims 1 to 5, wherein the backing is designed with a thickness of 0.05 to 0.5 mm and with 50 to 400 locking means per square centimeter.
7. The process according to Claim 6, wherein the backing is designed with a thickness of 0.05 to 0.3 mm, preferably 0.1 to 0.2 mm, and is provided with 100 to 400, preferably 200 locking means per square centimeter.
8. The process according to Claim 6, wherein the backing is designed with a thickness of 0.1 to 0.5 mm, preferably 0.2 to 0.3 mm, and is provided P1113 / 98MX with 50 to 200, preferably 100 locking means per square centimeter.
9. 9. An adhesive fastener element produced by the process claimed in any one of Claims 1 to 8.
10. 10. An adhesive fastener comprising at least one adhesive fastener element as claimed in Claim 9.
11. 11. A device for production of an adhesive fastener element as claimed in the Claim 9, which essentially consists of a dispensing mechanism of a thermoplastic and of a pressure roller and a forming roller which are mounted at a specific distance from one another to form a space, the forming roller has a mesh, whose openings are formed by electroplating, etching to the water, or by a laser.
12. 12. A device as claimed in Claim 11, wherein the mesh of the forming roller is made entirely of nickel.
13. 13. A forming roller for a device for the production of an adhesive fastening element designed as claimed in any of Claims 11 or 12. P1113 / 98MX