Patent Application
20120042483
The present invention relates generally to mechanical fasteners, and more specifically to a method for forming hooks directly on a fabric substrate, apparatus for performing the method, and article manufactured by the method.
A hook-and-loop type fastener is a well know mechanical fastener and wildly used in a variety of fields that need to fasten two separate parts together, such as garment, hats/caps, shoes, personal care product (such as diapers) etc., because of its easy engaging/disengaging characteristic. The hook-and-loop type fastener mainly consists of a hook strap on which an array of hooks are formed and a loop member on which a plurality of loops are formed to be engage with the hooks of the hook strap. In use, the hook strap 10, which includes a sheet of backing 11 and a plurality of hooks 12 integrally formed with the backing 11) bonded to a fabric substrate 14 with a layer of adhesive 13 to form a fabric material with a hook strap, as illustrated in
Although traditional fabric materials with a hook strap made by above-mentioned process may provide fastening effect in some applications, they still have shortcomings. For instance, because traditional fabric materials with a hook strap use an adhesive layer to bond the hook strap and the fabric substrate together, the overall thickness is inevitably increased and so is the manufacture cost. Additionally, because of the layered structure of the traditional fabric material with a hook strap its suppleness is too stiff in applications that suppleness fabric material with a hook strap is critical. For instance, when utilized in a diaper the fabric material with a hook strap usually is used as a fastening member to keep the diaper in place about the wearer. Therefore, if the fabric material with a hook strap does not have sufficient suppleness, the wearer of the diaper may feel uncomfortable and even may leave a mark on the skin of the wearer.
In view of the shortcomings of traditional fabric material with a hook strap described above, there exists a need for a fabric material having hook elements that possess a fastening function and a sufficient suppleness, and a method and an apparatus for making the same.
The object of the present invention is to provide a fabric material having hook elements that possess a fastening function and a sufficient suppleness so as to overcome the problems of existing fabric material with a hook strap, a method and an apparatus for making such fabric material.
One aspect of the present invention provides a method for forming hook elements directly on a fabric substrate, the method comprising: providing a rotatable molding roll having a cooling device disposed therein and a number of circumferential grooves formed in a peripheral surface thereof, each groove having a plurality of cavities formed in a bottom thereof along the groove with an interval between adjacent cavities; providing melted plastic material to the peripheral surface of the molding roll with pressure to fill the grooves and cavities with the melted plastic material; scrapping excessive plastic material from the peripheral surface of the molding roll; passing a web of fabric substrate through a nip formed by the peripheral surface of the molding roll and a peripheral surface of a thermo-pressing roller, wherein the thermo-pressing roller is disposed radially against the molding roll such that a pressure is applied to the fabric substrate, and is heated to a temperature to allow a portion of the plastic material in the cavities and grooves at the proximity of the peripheral surface of the molding roll and contacting the fabric substrate to be in a softened and fusible state so as to be fused to the fabric substrate and to thereby keep the fabric substrate attached to the peripheral surface of the molding roll; cooling the thermo-pressed fabric substrate so as to allow the plastic material in the cavities and grooves to be solidified to from the hook elements and to be fixed to the fabric substrate; and separate the fabric substrate on which a plurality of hook elements are formed from the peripheral surface of the molding roll.
According to one embodiment of the present invention, the grooves are formed in parallel along the peripheral surface of the molding roll. Additionally, the grooves may be formed in the peripheral surface of the molding roll in straight-line form, wave form, or zigzag form. The cavities in each groove may be aligned with the cavities in adjacent grooves or may be offset from each other. The fabric substrate comprises a non-woven fabric.
Another aspect of the present invention provides an apparatus for forming hook elements directly on a fabric substrate, the apparatus comprising: a molding roll rotatable in a direction having a cooling device disposed therein and a number of circumferential grooves formed in a peripheral surface thereof, each groove having a plurality of cavities formed in a bottom thereof along the groove with an interval between adjacent cavities; an extruder having a nozzle for providing melted plastic material to the peripheral surface of the molding roll with pressure, the nozzle being disposed close to the peripheral surface of the molding roll with a gap formed therebetween; a scrapper disposed at a position downstream from the extruder in the molding roll rotating direction and an edge thereof contacting the peripheral surface of the molding roll; a thermo-pressing roller disposed against the molding roll such that a nip is formed between the peripheral surface of the molding roll and a peripheral surface of the thermo-pressing roller and at a position downstream from the scrapper in the molding roll rotating direction, wherein the peripheral surface of the thermo-pressing roller is heated to a temperature that is able to allow the plastic material in a state of being fusible under pressure; a fabric substrate feeding roller for providing a web of fabric substrate through the nip between the molding roll and the thermo-pressing roller so as to allow a portion of the plastic material in the cavities and grooves at the proximity of the peripheral surface of the molding roll and contacting the fabric substrate in a fusible state so as to be fused to the fabric substrate and to thereby keep the fabric substrate attached to the peripheral surface of the molding roll; external cooling means disposed about the peripheral surface of the molding roll at a position downstream from the thermo-pressing roller in the molding roll rotating direction for cooling the fabric substrate attached to the molding roll so as to allow the plastic material in the cavities and grooves to be solidified to from the hook elements and to be fixed to the fabric substrate; and a striping device for separating the fabric substrate on which a plurality of hook elements are formed from the peripheral surface of the molding roll.
The nip between the molding roll and the thermo-pressing roller may be adjusted by moving the thermo-pressing roller relative to the molding roll so a to make the nip slightly smaller than the thickness of the fabric substrate.
Still another aspect of the present invention provides a fabric material having hook elements that is manufactured by the method of the present invention, the fabric material comprising a fabric substrate and a plurality of hook strips formed directly to the fabric substrate, wherein each of the hook strips includes a number of integrally formed hook elements and adjacent hook elements in the same hook strip are connected by plastic material strips slighter wider than the hook elements, and there is no plastic material between adjacent hook strips.
Features and objects of the present invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings.
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein:
a, 4b, and 4c are the top view, side view and end view of the fabric material having hook elements according to one embodiment of the present invention, respectively.
Referring now to embodiments illustrated in
As illustrated in
The thermal-pressing roller 50 is disposed at a position downstream from the scrapper in the rotation direction A of the molding roll 20 with a peripheral surface thereof radially opposed and intimately close to the peripheral surface of the molding roll 20 to have a nip formed therebetween. The fabric substrate feeding roller 82 is disposed to supply a web of fabric substrate 80 through the nip. Preferably, the nip may be adjusted by moving the thermo-pressing roller 50 radially relative to the molding roll 20 so a to make the nip slightly smaller than the thickness of the fabric substrate 80 and thus a pressure in the thickness direction of the fabric substrate 80 may be applied to the fabric substrate 80. The external cooling device 60 may be a cooling fan and is disposed at a position downstream from the thermo-pressing roller 50 in a the rotation direction A of the molding roll 20 for blowing a cool air stream toward the peripheral surface of the molding roll 20. The stripping rollers 70 are disposed at a position downstream from the external cooling device 60 in a the rotation direction A of the molding roll 20.
When manufacturing a fabric material having hook elements with the apparatus 100 described above, a thermoplastic material (for example, polyethylene) is firstly supplied to the extruder 30 and is heated up to 235° C. to make the thermoplastic material in a melted state. The melted thermoplastic material is then ejected through the nozzle of the extruder 30 onto the outer periphery surface of the rotational molding roller 20 and into the grooves 22 and cavities 24. The thermoplastic material in the grooves 22 and cavities 24 is cooled by the cooling water circulation system and gradually solidified. Then, with the rotation of the molding roll 20, excessive thermoplastic material on the peripheral surface of the molding roll 20 is scraped off from the peripheral surface of the molding roll 20 by the scrapper 40. In other words, after the scrapper 40 scrapping the peripheral surface of the molding roll 20, thermoplastic material only exists in the grooves 22 and cavities 24, and no thermoplastic material on the peripheral surface of the molding roll 20. This is completely contrary to the traditional method for extrusion molding a hook strap in which a layer of thermoplastic material is left on the peripheral surface of a molding roll to from a backing of the hook strap.
Next, passing a web of fabric substrate 80, in this embodiment a non-woven fabric, through the nip between the molding roll 20 and the thermo-pressing roller 50. By heating the peripheral surface of the thermo-pressing roller 50 to a proper temperature (such as, in the case the thermoplastic material is a polyethylene, the temperature is about 235° C.), a portion of the thermoplastic material in the cavities 24 and grooves 22 at the proximity of the peripheral surface of the molding roll 20 and contacting the fabric substrate 80 turns into a softened and fusible state, and with the pressure applied by the thermo-pressing roller 50 this portion of the thermoplastic material may penetrate into fabric substrate 80 and thus combine the thermoplastic material in the cavities 24 and grooves 22 with the fabric substrate 80, and the fabric substrate 80 is thus attached on the peripheral surface of the molding roll 20 and rotate therewith. Then, the thermo-pressed fabric substrate 80 is cooled by the cool air stream blew toward it by the cooling fan 60 while rotating with the molding roll 20 so as to solidify the thermoplastic material penetrated into the fabric substrate 80 to thereby firmly fixing the hook elements formed in the cavities 24 to the fabric substrate 80. Then, the fabric substrate 80 on which a plurality of hook elements are formed is separated from the molding roll 20 by the stripping rollers 70 to form a fabric material 90 having hooks (see
a, 4b, and 4c are the top view, side view and end view of the fabric material 90 having hook elements according to one embodiment of the present invention, respectively. As shown in
The present invention utilizes a technique that is completely opposite to the traditional technique for forming a fabric material having hooks. Specifically, in the traditional technique, a sheet of hook strap is separately injection molded and then bonded to a fabric substrate through an adhesive layer. The present invention on the other hand forms the hook elements directly onto the fabric substrate. Most importantly, because the fabric material made by the present invention does not have a hook strap that covers the entire surface of the fabric substrate, the fabric material provided by the present invention not only has fastening functionality but also has great suppleness.
Although the present invention has been described above according to preferred embodiments of the fabric material, the apparatus and method illustrated in the accompanying drawings, this does not mean that the scope of the present invention is limited to specific configurations of the fabric material and apparatus, and the steps or sequences of the method described above. In fact, there exist various modifications and variations under the principle and spirit disclosed above. For instance, although it is illustrated in
It will be apparent to people skilled in this art that many modifications can be made to the disclosed structures without departing from the true scope of the invention defined by the appended claims. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the spirit and scope of this invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 099127571 | Aug 2010 | TW | national |
