WO2000054959A1

WO2000054959A1 - Method for producing molded parts

Info

Publication number: WO2000054959A1
Application number: PCT/EP2000/001053
Authority: WO
Inventors: Josef Fusseder; Otto Wiesmayer; Klaus NÄGELE
Original assignee: Gottlieb Binder Gmbh & Co; Kunststofftechnik Wiesmayer Gmbh; F & G Kunststofftechnik Gmbh
Priority date: 1999-03-16
Filing date: 2000-02-10
Publication date: 2000-09-21
Also published as: EP1161335A1

Abstract

The invention relates to a method for producing molded parts from interlocking fastening elements (10) which consist of a thermodeformable plastic material. The respective interlocking fastening element (10) is heated at least to its molding temperature and is then brought into the defined shape by way of at least one molding tool (12). The invention provides a method for producing molded parts in the form of interlocking fastening elements that affords geometries of the interlocking fastening elements that can be produced at low costs and that can be immediately used for a large number of applications.

Description

Process for the production of molded parts

The invention relates to a method for producing molded parts from adhesive fastener parts.

DE 198 28 856 C1 discloses a process for the manufacture of adhesive fastener parts for this purpose. In the known method for producing the adhesive fastener part with a multiplicity of interlocking means formed in one piece with a carrier, a thermoplastic plastic is fed into a gap between a printing tool and a molding tool, in which a screen having continuous cavities is used as the shaping element on the molding tool and in which the Interlocking agents are formed in that the thermoplastic material at least partially hardens in the cavities of the sieve. In this case, such a molding tool is used which, on the side of the screen facing away from the printing tool, has a second shaping element which interacts with its cavities and by which the thermoplastic material can be molded in such a way that a type of Crooked closure part is created with very small stem geometries on which the interlocking heads are arranged.

The Mi krohaftverschlußteil obtained in this way forms flat sheet-like blanks and can also be obtained as a strip material. Such fasteners with their fastener parts or hooking elements of one type form with correspondingly designed fastener parts with hooking elements of the other type releasable fasteners which are not only used today for the clothing industry or are used in the area of floor fastenings but also as fasteners in mechanical engineering or in the motor vehicle industry. If the addressed fastener part is to be fixed on a motor vehicle part, for example on a seat component, in order to enable the covering of a side airbag on the corresponding seat part, the fastener is cut out of the full material of the fastener according to the required three-dimensional geometry and then the seat contour is adapted and gradually by gluing or the like relocated. The laying method in question is very time-consuming and therefore very cost-intensive. Since the sometimes complicated three-dimensional geometries can be reproduced by the flat band or flat material of the closure part, there are limits to the laying technique, since not every geometry can be reproduced in this way.

On the basis of this prior art, the object of the invention is to provide a method for producing molded parts from adhesive fastener parts which leads to adhesive fastener part geometries which can be produced inexpensively and which are suitable for a large number of applications. application cases can be used immediately. A corresponding object is achieved by a method having the features of claim 1.

The fact that the adhesive fastener parts consist of a thermally deformable plastic material, in which the respective fastener part is heated at least to its shaping temperature and then brought into its predeterminable shape by means of at least one shaping tool, means that a fastener part that is completely adapted to the circumstances can be predefined within a kind of deep-drawing process Generate geometries which can then be used directly on site, for example connected to a seat cushion or the like. Time and cost-intensive cutting and laying work are thus eliminated.

It is surprising for a person skilled in the field of fastener technology that using a deep-drawing process can lead to complicated fastener geometries without the fastener and its fastener parts being damaged by thermal influences during the molding process. It is also surprising that during deep drawing, the structures of the interlocking elements do not change so negatively that they can no longer be used later with corresponding closure parts of a further adhesive closure part for producing the adhesive closure.

It has proven to be particularly advantageous to subject the molding process to adhesive fastener parts as micro-adhesive fasteners, as are the subject of their manufacturing process according to DE 198 28 856 C1.

In a particularly preferred embodiment of the method according to the invention, the shaping tool is heated, the mold to be Mende adhesive fastener part is heated to its molding temperature before the actual molding process. This ensures a particularly inexpensive and gentle heat treatment for the adhesive fastener part.

In a further preferred embodiment of the method according to the invention, after the shaping process, the adhesive closure part taking a shape is cooled until it solidifies. As a result of this cooling, the molded adhesive closure part can be passed on for later processing and use more quickly. A correspondingly controlled cooling can also avoid undesirable shrinking processes on the adhesive fastener part.

In a particularly preferred embodiment of the method according to the invention, the adhesive closure part is heated via an additional heat source, in particular in the form of an infrared heat source, during the molding process. This facilitates the molding process for the adhesive fastener part. A diffusion device is preferably used to avoid damaging heat input into the adhesive closure part, in particular along its outer end edges. This prevents heat peaks in the material.

In a further preferred embodiment of the method according to the invention, the adhesive fastener part to be deformed is held in a tenter frame and deformed there by the shaping tool. The clamping frame holds the adhesive fastener part to be deformed, in particular along the mentioned end edges. In a particularly preferred embodiment of the method according to the invention, a vacuum is generated on the shaping surface of the shaping tool by means of a vacuum device. This ensures that the touch-and-close fastener part lies flush against the shaping tool and is held by the clamping frame. The shaping tool for a shaping process of the touch-and-close fastener part is preferably moved relative to the latter. In order to protect the interlocking elements during the shaping process, they are arranged facing away from the shaping tool within the shaping device, and the shaping tool rather acts on the fastener part via the smooth support surface.

The method according to the invention is explained in more detail below with reference to the drawing. The sole figure shows a basic and not to scale representation in a side view of the basic structure of the shaping device.

For the method according to the invention, band-shaped or sheet-like fastener parts are used which consist of a thermally deformable plastic material, for example of microporous polypropylene material. Such adhesive fastener parts can be obtained, for example, via a manufacturing process according to DE 198 28 856 C1. To carry out the known manufacturing process, an extruder head serves as a feed device for thermoplastic plastic which is in a plastic or liquid state and which is fed as a band, the width of which corresponds to that of the adhesive fastener part to be produced, to the gap between a printing tool and a molding tool. A pressure roller is provided as the printing tool. The molding tool is a molding roller. Both rollers are opposed to each other set directions of rotation driven, so that a conveyor gap is formed between them, through which the plastic band is conveyed in the transport direction, while at the same time the plastic band is formed in the gap to the carrier of the adhesive fastener part and the carrier on the side adjacent to the form roller through the shaping elements of the form roller receives the shape required to form interlocking means.

For this purpose, the shaping roller has two shaping elements on the circumference in the form of a sieve, namely an outer sieve and an inner sieve, which lie against one another. The two sieves are inserted into one another in such a way that the cavities formed by the sieve openings of the outer sieve and inner sieve are aligned with one another with a common axis. In the course of this shaping process, protruding stems with thickened ends are formed on the carrier tape. The hooking or closing parts in question can be made geometrically very small, so that a type of micro-adhesive closure is created. Furthermore, the head ends are essentially flush with one another and form a type of further contact surface running parallel to the carrier surface. Furthermore, the number of closure or hooking elements per cm ^{2 of} carrier material can be made very high. The pertinent Mi krohaftverschlußteil, which is designated in the figure with 10, is shown only schematically there, the closure or interlocking elements (not shown) being arranged in the direction of view of the figure and the adhesive closure part 10 forming a smooth support surface on the underside. The mentioned micro adhesive closure part 10 is particularly well suited for a shaping process, since in view of the geometrically small size of the interlocking elements and their small spacing from one another during the shaping process, the geometries do not change at all and the spacing of the closure elements from one another only changes slightly. Accordingly, a fully functional adhesive closure part is still available after the shaping process.

A shaping tool 12 is used for the deformation of the adhesive fastener part 10, and can be moved up and down in the direction of the longitudinal axis 14, as viewed in the direction of the figure. The shaping tool 12 can consist of a movable carrier plate 16, the actual shaping tool 18 being arranged on the top of the carrier plate 16 in an exchangeable form.

The shaping tool 12 is heated, the adhesive closure part 10 to be deformed being stored as a semifinished product on rolls or the like and being heated to its actual shaping temperature by a separate thermoforming system, for example to 170 ° C., the temperature value being dependent on the actual shaping process is of the plastic material to be used. The molding tool 12 itself is preferably preheated to approximately 75 ° C. and maintains this temperature during the molding process. An additional heat source 20 is an infrared heat source, which keeps the adhesive closure part 10 heated to its object temperature, here 170 ° C., during the molding process, and when this temperature is reached on the molding tool 18 of the shaping tool 12 by means of a vacuum device (not shown), a vacuum or very quickly A vacuum is created in order to ensure the molding process of the adhesive closure part 10 in a defined manner. In order to avoid damaging heat being introduced into the adhesive fastener part 10 during the heating and molding process, in particular along its end edges, a diffusion device 22 is provided, in the form of a diffusion grid, which has a scatter in the lateral areas of the molded surface of the adhesive fastener part 10 of infrared waves from which Heat source 20 originated, so that thermal damage to the plastic material to be deformed (microporous polypropylene) can be excluded. The diffusion device 22 in question is fastened to a tensioning frame 24 which surrounds the adhesive closure part 10 on the outer circumference side, as shown in the figure, by the clamping jaws of the tensioning frame 24 non-positively engaging over the circumference of the adhesive closure part 10. As a result, the adhesive closure part 10 is securely fixed within the clamping frame 24 for a molding process. The shaping tool 12, as already illustrated, is moved for a shaping process of the adhesive closure part 10 relative to the latter by the adhesive closure part 10 being fixed and the shaping tool 12 moving towards and away from the clamping frame 24 with the adhesive closure part. However, other arrangements are also conceivable in which, for example, the tensioning frame 24 places the adhesive fastener part 10 on the shaping tool 12 from above.

After the molding process, the adhesive fastener part 10 is cooled, for example by means of blown air, until the solidification point occurs. It is surprising that the burdock adhesion is completely retained. With the molding method according to the invention, conventional adhesive fastener parts can be obtained as deep-drawn parts and can thus be used in a large number of fields of application. Thereby even complicated geometrical three-dimensional structures can be realized through the deep-drawing property.

Claims

Patent claims

1 . Method for producing molded parts from adhesive fastener parts (10) consisting of a thermally deformable plastic material, in which the respective adhesive fastener part (10) is at least heated to its shaping temperature and then brought into its predefinable shape by means of at least one shaping tool (12).

2. The method according to claim 1, characterized in that the shaping tool (12) is heated and that the adhesive fastener part to be deformed (10) is heated to its shaping temperature before the actual shaping process.

3. The method according to claim 2, characterized in that after the shaping process, the shape-taking fastener part is cooled until it solidifies.

4. The method according to any one of claims 1 to 3, characterized in that the adhesive closure part (10) is heated via an additional heat source (20), in particular in the form of an infrared heat source, during the molding process.

5. The method according to claim 4, characterized in that by means of a diffusion device (22) damaging heat input into the adhesive fastener part (10), in particular along its end edges, is avoided.

6. The method according to any one of claims 1 to 5, characterized in that the adhesive fastener part to be deformed (10) held in a clamping frame (24) is deformed by the shaping tool (12).

7. The method according to any one of claims 1 to 6, characterized in that a vacuum is generated by means of a vacuum device on the shaping surface of the shaping tool (12).

8. The method according to any one of claims 1 to 7, characterized in that the shaping tool for a shaping process of the adhesive fastener part (10) is moved relative to this.

9. The method according to any one of claims 1 to 8, characterized in that the adhesive closure part (10) is formed from a flat surface material before the shaping process and leaves the shaping tool (12) as a deep-drawn part after the shaping process.

10. The method according to any one of claims 1 to 9, characterized in that the adhesive closure part (10) is fed to the shaping tool (12) such that its interlocking elements face away from the shaping tool (12) and its smooth carrier surface faces it.