Buckles – buttons – clasps – etc. – Including readily dissociable fastener having numerous,... – Having mounting surface and filaments constructed from...
Reexamination Certificate
2002-03-07
2004-01-20
Sakran, Victor (Department: 3677)
Buckles, buttons, clasps, etc.
Including readily dissociable fastener having numerous,...
Having mounting surface and filaments constructed from...
C024S306000, C024S442000, C024S443000, C024S446000, C024S450000, C264S145000, C428S099000
Reexamination Certificate
active
06678924
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a surface fastener obtained by molding a flat substrate and a plurality of engaging elements integrally and continuously using thermoplastic resin, and a manufacturing method and a manufacturing apparatus therefore. More particularly, it relates to an integral molded surface fastener in which the engaging elements are not likely to fall down despite their minute dimensions and engage fine pile pieces such as unwoven fabric securely so as to ensure a necessary engaging force, separation force and a high engaging ratio. Further, this surface fastener being capable of bearing repeated engaging/disengaging operations several times and preferable for particularly, a paper diaper, medical simple clothes, napkins, various kinds of working simple clothes, underwear and the like, and a continuous manufacturing method and a continuous manufacturing apparatus for the surface fastener are related to.
2. Description of the Related Art
In recent years, the surface fastener having a plurality of the engaging elements of minute dimension integrally on a flat substrate obtained by injecting thermoplastic resin continuously has been used in various fields as a fastener of a disposable paper diaper, medical simple clothes, napkins, various kinds of working simple clothes, underwear and the like. Forms of this kind of the engaging element of an integral molded surface fastener are divided largely to hook type and mushroom type as well known in a related filed.
A typical hook type integral molded surface fastener has been disclosed in for example, U.S. Pat. Nos. 4,984,339 and 5,537,723. According to these molded surface fasteners, molten resin is supplied to the circumferential face of a cylindrical drum, in which a plurality of substantially J-shaped cavities while each cavity is curved from an inside of the drum and opened to the circumferential face are formed, so as to mold a thin plate-like substrate along the circumferential face. At the same time, the cavities are filled with part of the molten resin so as to mold an inverted J-shaped hook integrally with the rear face of the substrate. After cooling, the molded product is separated from the circumferential face of the drum.
Further, an integral molded surface fastener having modified configuration of the aforementioned hook-type engaging elements has been also disclosed in for example, Japanese Patent Application Laid-Open No. 2-5947 and Japanese Patent Application Laid-Open No. 6-133808. In manufacturing these molded surface fasteners, molten resin is extruded from an extruding die having an opening erected in a substantially two-leaves palm tree or T-shape on a narrow slit extended in the horizontal direction so as to mold a multiple rows of ribs each having a palm-tree or T-shaped section in the extruding direction on a thin plate-like substrate, thereby providing a primary molded product. Next, the rib of the primary molded product is cut in a predetermined thickness in the length direction successively and the palm tree shaped or T-shaped engaging elements are formed closely. Then, the substrate is expanded in the molding direction so as to separate respective engaging elements at a desired pitch, so that a molded surface fastener having a final configuration is produced.
Recently, a molded surface fastener having a hook type engaging element, whose shape is novel and never seen before and provided by changing a configuration of the conventional hook type engaging element largely, has been developed. Those molded surface fasteners have been disclosed in for example, Japanese Patent Application Laid-Open No. 9-322812 and Japanese Patent Application Laid-Open No. 11-56413. The engaging elements disclosed in these publications comprise an erected portion which is erected upward from the surface of the substrate, a neck portion which is separated in the molding direction with a V-shaped gap at a top end of the erected portion and an engaging head extended substantially horizontally back and forth in the molding direction from the neck portion. Further, a bottom face of the engaging head is inclined obliquely upward toward a front end thereof and a top face of the engaging head is flat. Additionally, a wing-like expanded portion having a thickness predetermined vertically is expanded each from the right and left side of the top face portion as viewed from the front in the molding direction.
As for the basic manufacturing method, primary molding technology using the aforementioned cylindrical drum is applied. However, the engaging element to be molded on the surface of the substrate at the time of molding is not molded in a J-shape from the beginning, but by molding a primary engaging element material having a substantially Y-shape having two V-shaped branch portions at a top end of the erected portion, as viewed from the side in the molding direction. Then, a preliminary molded product having a plurality of the primary engaging element materials on the substrate is produced. Consequently, the branched portion of said primary engaging element material of the primary molded product is heated with pressure so as to be deformed, so that the aforementioned engaging element having a peculiar configuration never seen before is molded.
On the other hand, the mushroom type molded surface fastener has been well known since before. According to, for example, U.S. Pat. No. 3,192,589, a primary molded product in which a plurality of column portions are erected on the surface of the substrate is molded. After that, a front end of the column portion of the molded product is soften by heating so as to mold a semi-spherical engaging head, thereby producing a molded surface fastener. Further, for example, Japanese Patent publication No. 8-508910 has disclosed an improved technology of the mushroom type molded surface fastener. In the molded surface fastener disclosed in this publication, a front end of the column portion of the primary molded product is softened by heating with pressure, so that a disc type engaging head is molded instead of the aforementioned semi-spherical engaging head.
Because the aforementioned mushroom type engaging element engages in all directions, it has been well known that it ensures a higher engaging strength and separation strength than the hook type engaging element whose engagement has a directivity. However, the mushroom type engaging element engages pile with its engaging head such that the pile winds around the neck portion of the engaging element, that is, the pile is hung from the neck portion. Therefore, there is a high possibility that the engaging element may be cut at the neck portion or the pile itself may be cut out when it is intended to release the pile from the engaging head. Thus, this type of engaging element often cannot bear repeated use and the engagement strength and separation strength are likely to be excessively increased.
The molded surface fastener disclosed in the aforementioned Japanese Patent publication No. 8-508910 is improved based on advantage and disadvantage of the mushroom type engaging element. The configuration of the engaging head is formed in a substantially disc-shape so as to intensify engagement ratio with minute pile and its separation strength is set appropriate. Consequently, this molded surface fastener can be applied as a fastener for the minute pile in various kinds of unwoven fabric, which is attached to the aforementioned disposable diaper and the like. As described above, application of such a fastener has been expanded rapidly and a further improvement has been proposed in for example, International Publication WO98/57565. In the improvement, it is intended to increase plasticity of the engaging head by forming a plurality of minute unevennesses on the top face of the disc-shaped engaging head.
On the other hand, the hook type engaging element is more likely to engage the pile as compared to the mushroom type engaging element and capable of securing appropriate engagement strength and sep
Akeno Mitsuru
Murasaki Ryuichi
Ohsugi Shintaro
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Sakran Victor
YKK Corporation
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