MXPA99011460A - Superimposed embossing of capped stem mechanical fastener structures - Google Patents

Abstract

There is provided a method of capping mechanical fasteners from a web having an array of upstanding stems. A heated surface member is positioned opposite a support forming a nip into which the web is fed. The heated surface member has a series of laterally spaced elongated peak and valley structures such that more than one peak and valley structure contacts and deforms each stem structure. The peak and valley groove structures provided asymmetric elongation and deformation of top portion of the stem structures forming hook heads.

Description

SUPERPOSED FINISHING OF STRUCTURES OF MECHANICAL FASTENERS OF FILTERED FILAMENTS FIELD AND BACKGROUND OF THE INVENTION The present invention relates to a method and an apparatus for finishing vertical filaments to form hooks of mechanical fasteners. More particularly, the invention relates to a method for forming asymmetric topped hook configurations with greater uniformity and ease of manufacture. Hook and eyelet mechanical fasteners are widely used for a wide range of products and applications. The methods for forming hook materials for use in these mechanical fasteners of the eyelet and hook closure type are very diverse. During these years it has been found that the hooks have different hooking mechanisms and characteristics according to the materials of the eyelet, depending on the hooks and / or the eyelet. This limits the practical applicability of any particular hook forming technique to produce hooks that can be applied to only certain types of uses or for use with only certain types of corresponding eyelet materials. Some of the first hook materials are REF .: 32209 formed using the procedures described in U.S. Patent Nos. 2,717,437 and 3,009,235 wherein special warps of vertical nylon yarn are cut so as to form nylon hooks with the open end and non-functional vertical filaments. The hooks formed by these types of methods are large (e.g., approximately 2 mm) requiring the use of open hair eyelet materials and have a rather low number of hooks per unit area. These hooks are also quite abrasive and therefore are not very suitable for uses in which the hooks could be in contact with sensitive skin. Hooks of this type are still used today due to durability in prolonged use. Similar types of hook structures are formed according to the method of U.S. Patent No. 3,594,865 where a thermoplastic material is formed directly on a "J-shaped" wire hook using deep J-shaped dies. Wire are formed in a continuous loop of mold material, which passes through an extruder.The extruder pushes molten plastic, such as nylon, into wire dies while also impregnating a fabric that is immediately below the material of wire die mold Exiting the extruder, the excess thermoplastic resin is separated from the surface of the wire matrix molds The flexible hooks remain in the back when the matrix is removed essentially by pulling the hooks now solidified and of the backing away from the mold material of the wire matrix, US Patent No. 3,594,863 refers to a similar apparatus for oducing a band that has filaments. The two patents indicate that the described methods can produce a wide variety of forms. U.S. Patent No. 3,594,865 states that the traditional method for directly injection molding a hook is limited to shapes that have to be tapered from the base to the tip. However, the hook shapes formed by these patents are relatively large and the hooks have to taper from the outer face to the opposite face along the length of the hook. The types of traditional molded hook shapes indicated in U.S. Patent No. 3,594,865 are like those described in U.S. Patent Nos. 4,984,339 and 5,315,740. These patents disclose shaped J-shaped hooks having a profile defined by a generally concave face, with smooth inner contour and an outer face of generally convex shape. The hook tapers continuously and smoothly from the base of the hook to the free end of the hook. The hook is designed in such a way that it will not deform to release a buttonhole engaged in the hook in cutting mode or with a desired applied force. The latter-mentioned patent discloses a similar hook having a low displacement volume for the area defining the tip of the hook. This is described as being convenient for use in applications such as disposable diapers and the like. Although these J-shaped hooks are generally adequate performance materials, they are very difficult to manufacture, particularly when making very small hooks such as those described in Patent No. 5,315,740. The small, complex shaped mold cavities are very difficult to manufacture and when they form extremely small hooks a proportionally larger number of mold cavities of J-shaped hooks have to be formed. The mold cavities of small complex shape are also much more susceptible to clogging and loss of definition of the molding cavity due to wear. Extremely flexible and inexpensive methods for forming hooks of a wide variety of sizes and shapes are described in PCT applications Nos. WO 94/23610 and 92/04839, as well as in the U.S. series No. 08 / 723,632. Using the methods described in these patents and patent applications, a backing having a large number of vertical thermoplastic filaments is fed through a gap between a contact line formed, for example, by two calender rolls. The upper contact line is smooth and heated so that the distal ends or tips of the filaments are deformed under heat and mechanical pressure, forming various types of finishing structures depending on the conditions of the selected contact line, the Relative velocity of the filaments in the contact line, and the size and shape of the filaments. The non-deformed filament portion and the generated cap together form a hook structure. The precursor material, a backing having vertical undistorted thermoplastic filaments, can be formed by molding techniques. However, the formation and use of mold cavities in the vertical filament form is much simpler and less problematic than the formation of J-shaped hook molds. For example, these simple mold cavity shapes have much less possibility of clogging or wearing out adversely, depending on the selection of mold materials. In addition, it has been found that using this method it is relatively easy to form large numbers of severed hooks very closely per unit area, which is particularly convenient for engagement with materials of relatively non-woven or non-woven eyelets. These slightly fluffy eyelet materials are generally also inexpensive, which makes this hook structure extremely convenient for low cost limited use applications such as disposable garments. The feel of these hook materials is also advantageous. Due to the high density of hooks and / or because the hooks have a flat or relatively flat top surface, the hooks are extremely pleasant to the skin, non-abrasive and have a film-like texture. Preferred hook materials are those which are essentially difficult to perceive as such at casual contact of the skin. This makes the hooks useful for disposable garments worn close to the skin (eg, diapers or surgical gowns). The present invention relates to a method for improving the aforementioned method of forming hooks and hooks formed by it.

DESCRIPTION OF THE INVENTION In the method for forming mechanical finned filament fasteners of the present invention, a precursor fabric material having a set of vertical thermoplastic filaments projecting distally from at least one surface of the fabric backing is provided. The vertical filaments are generally of a substantially constant width along the length of the filament or can taper from the base to the tip. A heated surface element is positioned opposite to a supporting surface element to form a contact line, which preferably extends across the width of the fabric or backing surface that has the vertical filaments and also along of the length of the fabric at a given distance forming a compression zone. The precursor fabric is fed into the contact line that forms a separation. The separation tapers from a given initial width in the compression zone. The tips of the filaments are initially engaged in a width of the given inlet spacing and are compressed in the contact line to a width of the given final spacing. In this compression zone the contact line progressively engages and compresses the polymer filaments between the surface element of the heated contact line and the support surface element. Although this compression is preferably continuous, it can be intermittent and / or at different compression values in the compression zone determined by the width of the gap. This heat and this compression cause the distal ends of the vertical thermoplastic filaments to be deformed into finished structures which can hook a fibrous eyelet material. In at least one portion of the compression zone, the surface of the heated contact line element is provided with at least one series or set of laterally spaced elongated peaks and valleys (grooves), wherein the average depth between the peak and the valley is generally from 5 to 500 microns, preferably from 10 to 200 microns, more preferably from 15 to 150 microns. The average spacing of the adjacent peak structures is less than the average width of the filament base immediately adjacent to the end portions of the filament before being deformed by the contact line. Preferably, the peak structures are spaced apart so that each end portion of the filament is brought into contact with two, preferably at least four, peak structures spaced laterally while being deformed. A given set of laterally spaced peak and valley structures preferably extends longitudinally at a distance at least equal to the average distance between adjacent vertical filament elements (closest neighbor distance averaging in at least two directions) and preferably at continuously along the length of the heated separation element in the compression zone. Similarly, sufficient peak and valley structures are provided in a given set so that the adjacent peak and valley structures of the set extend laterally at least a distance equal to the average distance between the adjacent vertical filament elements (neighboring distance plus near average in at least two directions). The peak and valley structures in the heated contact line element provide hooked filament hooks having a substantially increased directionality and, depending on the structure, more uniformity of the shape of the hook head across the length and width of the fabric without loss of functionality and generally a greater capacity for hooking the topped hooks formed with very soft and not very soft non-woven grommet materials. The present invention also relates to an apparatus for finishing a precursor fabric provided with a set of vertical thermoplastic filaments projecting from a cloth backing. The apparatus includes a heated surface element opposite the support surface element that forms a contact line, contact line that tapers preferably substantially continuously from an entry gap width to a final gap width defining a compression zone. A feeding element is provided for feeding a precursor fabric into and through the nip. The heated surface element of the contact line is provided with peak and valley structures as indicated above in at least a portion of the compression zone. Although the width of the contact line spacing preferably decreases continuously in the compression zone, the contact line can have a generally constant width of spacing along at least a portion of its length or the width of the separation may decrease and increase intermittently or decrease to different values, or combinations of those indicated above. Generally, the compression zone of the contact line is defined by a first inlet separation width and a second separation, preferably smaller than the first separation width defining a final separation of the contact line. The entry gap width of the given contact line is defined by the thickness of the backing substrate web and the average height of the vertical filaments at the point at which the tips of the filaments of the precursor web material engage first by compressing to the heated upper surface that defines the contact line. The final separation width is the narrowest gap width in the contact line after which the fabric and the tips or end portions of the deformed filaments are substantially released by compression with the surface element of the heated nip. The method and apparatus of the invention allow the formation of the distal ends of the thermoplastic filaments in a wide variety of asymmetrical top-off shapes oriented in any given direction, including asymmetric mushroom heads, elongated J-shaped hooks, hooks T shaped and the like still maintaining the advantages described in the prior art methods to form mechanical fastener hooks with topped filaments.

Brief Description of the Figures Figure 1 is a schematic illustration of a method for forming the web of material having vertical filaments for manufacturing the finned filament fasteners of the invention.

Figure 2 is a schematic illustration of a method for finishing using a calendering system.

Figures 3a and 3b are schematic illustrations of the orientation of the peak and valley microstructures of the capped surface, as shown in Figure 3c, in a calendering cylinder.

Figure 4 is a schematic illustration of an alternative apparatus for forming filament fasteners with heads according to the invention.

Figure 5 is a schematic illustration of an alternative apparatus for forming filament fasteners with heads according to the invention.

Figure 6 is a side view of a backing material containing filaments used in the present method of invention.

Figure 7 is a side view of a headed filament fastener as produced by the method of the invention.

Figure 8 is a perspective view of a headed filament holder produced by the method of the invention.

Figure 9 is an optical photograph of a headed filament holder produced by the method of the invention.

Detailed Description of the Preferred Modalities The method of the invention relates to the formation of mechanical fasteners of capped or headed filaments for use in mechanical fastener systems of the hook-and-eye fastener type or self-engaging mechanical fasteners. The invention initially relates to a method for crowning hook heads in a backrest comprising at least the following steps. First, a fabric is provided which is a cloth backing with a set of substantially vertical projections. The projections are formed by a base portion of substantially vertical filaments and an end portion of filament or hook head. Everywhere the fabric has a first average thickness. Also provided is a contact line having at least a first heated surface element and at least a second opposing surface element. The contact line has a separation, which in turn has a compression zone defined by a first inlet separation width and a second final separation width. The first width of separation is substantially equal to or less than the first average thickness of the fabric. The second final separation width is less than the first thickness of the fabric and is the smallest separation width of the contact line. The at least one heated surface element is provided with at least one set of peak and groove structures extending longitudinally in at least one first direction in the compression zone. The average spacing between the adjacent peak structures is generally less than the average width of the filament base portion immediately adjacent to an end portion of the filament or to a hook head. In addition, the at least one set of peak and groove structures generally extends longitudinally at a distance at least equal to the average distance between the base portions of adjacent vertical filaments. The fabric is then moved along a fabric path in, and through, the compression zone in a second direction, such that at least a portion of the set of substantially vertical projections is preferably deformed by the web element. heated surface in at least the first direction defined by at least one set of peak and groove structures. The first direction may be substantially parallel to the second direction in which case the relative velocity of the heated surface element and the fabric may be the same or different and the hook heads formed or modified by the heated surface element are provided with an orientation in the direction of movement of the fabric. If the first address and the second address are substantially different, the relative speed of the heated surface element and the fabric are generally substantially the same. Similarly, if more than one set of peak and groove structures is provided on the same heated surface element, a set of structures that is oriented to substantially different directions, then the heated surface element should move at the same relative velocity as the fabric Topped or headed filament hook fasteners can be formed using a backing material having a set of thermoplastic, plastically deformable, vertical filaments. These vertical filaments are preferably formed in an integral backing of the same thermoplastic material. Suitable thermoplastic materials include polyolefins such as polypropylenes or polyethylenes, polyamides such as nylon, polyesters such as poly (ethylene terephthalate), plasticized polyvinyl chloride, copolymers and mixtures thereof, optionally, with other polymers or plasticizers, or the like. A suitable method for forming this precursor material of a cloth backing having a set of vertical projections is shown in Figure 1. A preselected thermoplastic resin feed stream 4 is fed by conventional means into an extruder 6 that melts the resin and moves the heated resin to a matrix 8. The matrix 8 extrudes the resin as a wide ribbon of material on the mold surface 10, e.g. , a cylinder, which has a set of mold cavities 12 in the form of elongated holes, which are preferably tapered to facilitate the removal of the solidified resin from the mold cavities. These mold holes or cavities are preferably in the form of straight cavities (ie, only one axis in the longitudinal direction). The mold cavities can be connected to a vacuum system (not shown) to facilitate the flow of the resin into the mold cavities. This could require a blade or doctor blade to remove excess extruded material on the inside face of the mold cylinder. The mold cavities 12 preferably end in the mold surface having an open end for the inlet of the liquid resin and a closed end. In this case, a vacuum 14 could be used to evacuate at least partially the mold cavities 12 before entering the matrix 8. The mold surface 10 preferably matches that of the matrix 8 where they are in contact to avoid that the excess resin is extruded, eg. , the lateral edges of the matrix. The mold surface and the cavities can be cooled by air or water, or the like, before releasing the backing and the vertical filaments formed integrally from the mold surface such as by a release cylinder 18. This provides a cloth 20 of a back 30 having vertical filaments 28 formed integrally of thermoplastic material. Alternatively, the vertical filaments could be formed in a preformed backing or the like by extrusion molding or other known techniques. The filaments formed by the method of Figure 1, or similar methods, can be topped by the use of a heated nip that can be formed by two calendering cylinders, 22 and 24, as shown in Figure 2. The heated calendering cylinder 22 is brought into contact with a predetermined portion of a distal end 26 of the filaments 28 projecting upwardly from the backrest 30. The temperature of the cylinder will be that which easily deforms the distal ends 26 under pressure created by the contact lines in the compression zone 35 without causing the resin to stick to the surface of the roller 22. The surface of the roller 22 can be treated with release coatings resistant to high temperatures to allow higher temperatures and / or more prolonged contact between the tips of the filaments or distal ends 26 and the heated roller 22. In the method of the invention, the surface of, for example, the heated cylinder 22 is provided with a series of valleys or grooves 40 and spacer peaks 42, the width of the grooves 41 is defined by the peaks 42, or edge regions 43 of the peaks 42, which also define the depth of the grooves 45 with the lowest point 44 of the grooves 40. As shown in Figure 3c, the peaks 42 may have a defined apex, however, the upper parts of the peaks could also be flat , curves or even have microstructures. Similarly, the grooves are generally shown as V-shaped, but may have other shapes such as U-shaped, rectangular, W-shaped or other shapes. Sets of peaks and grooves may extend continuously or intermittently in the transverse direction (Figure 3a) or longitudinal direction (Figure 3b) or at some intermediate angle or several sets of peaks and grooves may extend in different directions. The average depth 45 of the grooves 40 is generally from 5 to 500 microns, preferably from 10 to 200. Generally, the depth of the groove should be sufficient to direct the flow of the resin softened by heat from the distal end, 26. The average groove width 41 is preferably less than the average width of the distal ends 26 of the filaments 28. Generally, the average groove width 41 is such that the distal end 26 is contacted with 2 to 40 grooves, preferably 4. to 20 grooves while it is deformed. The depth and width of the groove are preferably uniform, however, they could vary significantly if desired. For example, a groove could increase or decrease the depth along the length of the grooves. Preferably, the minimum groove depth is at least 15 microns. Similarly, the peaks have a substantially uniform height. However, the heights of the peaks could vary or in certain cases, secondary or other transverse direction grooves could be used in one or more peaks. The secondary transverse grooves could be useful to provide more complex flow patterns during the finishing process and / or more evenly distribute the resin between the adjacent primary grooves. The primary grooves provide directional flow or deformation of the upper portion of the heat-softened filament in the contact line 21, forming a more asymmetric head 32 of the deformed distal end 26 of the filament. The increased asymmetric nature of these topped heads (reduction in the number of planes of symmetry) provides a better engagement with most fibrous eyelet materials. Generally, this is accompanied by an increase of the protruding part of the head without corresponding increases in the total transverse area of the upper portion of the head, flat or flat. With the above methods, by using a smooth heated surface element on the nip, any increase in the protruding portion beyond the filament of the topped head also proportionally increased the top flat flat portion capped by reducing penetration in the grommet materials. This improved asymmetric nature is particularly advantageous for providing hooks with projecting portions on two opposite sides of a given filament. The topped heads can also be easily oriented in any given direction or in a multiplicity of directions, a very advantageous feature and one which can not be obtained or which can only be obtained with great difficulty with the methods of the prior art. The finishing method of the invention can also be used to provide an increase in the directionality or protrusion for hook fasteners with pre-formed hook heads. These hook heads can be formed by means of a finishing method or other known techniques such as molding. The only requirement is that the hooks are formed in a substantially vertical filament as defined below. In this case, the average spacing between the adjacent peaks is less than the width of the hook head in the direction perpendicular to the longitudinal direction of the peaks and grooves. The process of the invention can easily form J-headed heads as disclosed in co-pending US application No. 08 / 723,632, as shown in Figures 6 and 7. In this method, the dimensions of the hook with J-shape 106 includes a height 110 of the precursor filament 28, a filament diameter 114, a final hook height 118, the distance between hooks 120, the opening width of the hook 122, the height of the opening of the hook 124, the thickness of the hook head 128 at the base of the hook head 106, the height of the hook head 129, the protruding part of the hook 109, as well as the total surface area of the flat upper portions of the hooks. The distal end portion of the filament is shown as 26 comprising the remainder of the filaments a base portion of non-deformed filaments. The size of the film or thickness of the backrest 132 further defines the band of hooks. The same dimensions can be found in other hook head shapes including mushroom shapes, umbrella shapes, T-shapes or the like. To form a fungus, umbrella, T-shape or the like, the relative velocity of the cylinder 22 substantially agrees with that of the fabric 30. To form J-shaped hooks, the backing or cloth 30 moves at a different speed than, for ex. , the heated cylinder (that is, faster or slower or even in opposite directions). Alternative methods (e.g., Figures 4 and 5) to produce the finished filament fasteners of the invention are disclosed in the co-pending US application, series No. 08 / 781,783. In the method and apparatus of Figure 4, a finishing apparatus 50 is used to form a capped filament holder 52 having numerous generally uniform hooks 32. A precursor fabric 20 having a backing 30 with a back surface 58 and a multiplicity of polymer filaments 28 projecting distally from a front surface 53 is directed to an inlet of a contact line 64. The entrance of the contact line 64 it is formed between a heated cylinder 66 and a curved support structure 68. The curved support structure 68 preferably has a shape that generally corresponds to that of the heated cylinder 66 at a slightly larger radius of curvature. The piston 80 provides a compressive force between the curved support structure 68 and the heated cylinder 66. The contact line 64 defines a first separation width of, entry in an entry of the contact line 72 and a second separation width. end in an outlet of the contact line 76 defining a compression zone 75. The second final separation width is preferably smaller than the first separation width. In the preferred embodiment, the separation width of the contact line 64 decreases continuously in a substantially linear proportion at least in some region. Preferably, this substantially linear change in the width of the gap occurs at least in a region immediately adjacent to the input gap width of the contact line between the entry of the contact line 72 and the line output. 76. In an alternative embodiment (not shown), the contact line 64 may decrease to a minimum value at an intermediate location between the entrance 72 and the exit 76 of the contact line or decrease then increase and then decrease again, etc. A fluid, such as air or water, can be introduced through the pipe 78 to the interface between the back surface 58 of the back 30 and the surface 116 to create a fluid support. The surface 116 may optionally be coated with a low surface energy material such as polytetrafluoroethylene (PTFE) or ultra high molecular weight polyethylene. Without air support, the back 30 tends to wrinkle when it enters the contact line 64, potentially causing breaks in the backrest 30. A piston 80 is provided to position the curved support structure 68 with respect to the heated cylinder 66. The curved support structure 68 it can also rotate along a turning point 82 to additionally adjust the separation width of the contact line 64 in the compression zone 75.

The relative speed of the heated cylinder 66 and the line speed of the precursor fabric 20 determine the overall shape of the capped filament hooks 32 in the finned filament holder 52. The rotation speed of the heated cylinder 66 may be greater than, less than or equal to the line speed of the precursor web 20. For some applications, the cylinder 66 may be stationary while the precursor web 20 moves across the line of contact. Alternatively, the cylinder 66 can be rotated in a direction opposite to the direction of movement of the precursor fabric 20. Figure 5 is an alternative embodiment of a method and an apparatus for forming capped filament fasteners 96. Opposite straps 92 and 94 have elongated portions defining a line of contact 90. The heat source 93 maintains the belt 92 at the desired temperature. The heated belt 92 forms an angle with respect to the belt 94 to form a continuously decreasing contact line 90. The precursor fabric 20 is fed into the contact line 90, where the filaments 28 are compressively engaged between the opposing belts. 92 and 94 in the compression zone 95. The heat and mechanical force deform the filaments 28 to form a filament fastener with head 96 with numerous finned filament hooks 98. The movement of the belts 92 and 94 is preferably synchronized to so that the relative line speed of belts 92 and 94 is generally the same. The synchronous movement of the straps 92 and 94 to form hook heads of more symmetrical capped filaments 98 around the filament (ie, generally symmetrical with respect to two or more reflection planes) is preferred. However, topped heads are not perfectly symmetrical (ie, finials in the form of circular mushrooms). Alternatively, the relative movement of the straps 92 and 94 may be slightly asynchronous to achieve asymmetric topped heads 98 around the filament (i.e., with one or fewer reflection planes), such as J-shaped hooks. It will be understood that a structure Stationary support can be replaced by the belt 94, in which case the support structure preferably includes a low friction surface, such as the air support mentioned above. The specific shape and orientation of the capped heads of the hooks 32 are determined by the relative size, spacing and orientation of the peaks and grooves on the heated surface element, the relative speeds of the fabric 20 and the web element. heated surface, as well as the temperature and shape of the heated surface element and the formed separation and the length of the compression zone. The grooves are preferably continuous and uniform through the heated surface element. The grooves can be oriented in the machine direction or oriented in the direction of movement of the fabric through the contact line in the compression zone, as shown in Figure 3b for a cylinder. This results in a finned filament head that is longer in the machine direction than in the transverse direction. The resulting shape is generally as shown in the schematic drawing of Figure 8. When using a groove that is oriented in the direction of fabric movement, if the groove depth varies in the machine direction, the heads Topped off symmetric type will have different degrees of elongation and topped heads of asymmetric type will have depths of minor grooves that generally correspond to the minimum groove depth. The topped heads of symmetrical type will have different dimensional or elongation relationships that depend on the depth of groove where it is put in contact with the filament. With the topped heads of asymmetric type the fabric and the heated surface move at different speeds making the areas of shallower grooves completely level the groove depth. It is also possible that the orientation of the grooves forms an angle in a heated surface element, with respect to the direction of the machine or the direction of movement of the fabric (as shown in Figure 3a for a cylinder) or provide sets of peaks and grooves of different orientation in the same heated surface element or different elements of heated surface. Where the peaks and grooves form an angle with respect to the direction of the machine, the topped heads resulting from elongated shafts can be provided at angles with respect to the longitudinal direction of the fabric, a feature that is not possible with the methods of the prior art using a cylinder of smooth heated surface without complex manufacturing techniques. However, when the peaks and grooves form an angle with respect to the machine direction, the relative speeds of the fabric and the heated surface element should substantially coincide to prevent the peaks from scraping or removing the filaments. The angle of the sets of peaks and grooves with respect to the direction of the machine can range from greater than zero to 180 degrees, an angle that could also vary with grooves that are not linear, such as curved, circular and the like. It is also possible to provide peaks and grooves only over a portion of the compression zone, which could be done by using more than one heated surface element to form multiple compression zones or a simple heated surface with a compression zone with peaks and grooves over only a portion of the compression zone. To ensure that each filament finds at least a portion of the compression zone with peaks and grooves, the surface element should be stationary or move at a speed that ensures contact of the filament with at least a portion having ridges and ridges. . In this manner, the ridges or grooves formed in the capped filaments could be subsequently smoothed or removed, if desired, by means of a smooth heated surface element or region following a heated surface element or region structured as a peak and valley. In general, the fastener hooks of capped filaments are in the form of a base portion of substantially vertical filaments forming an angle of approximately 90 degrees with the substrate of the backing, however, this angle can range between 80 and 100 degrees, preferably between 85 and 95 degrees. The capped head is formed by a distal end portion 26 of the filament and has a generally flat or flat upper surface usually having at least one thin region or groove (formed by the peaks of the heated surface element), and preferably 2 to 4. thin regions or grooves and more preferably 4 to 20 thin regions or grooves. The topped heads are elongated in the direction of the thin regions or grooves such that the heads have a length-to-width aspect ratio of at least about 1.1: 1, preferably at least 1.4: 1 and more preferably 1.5: 1 taken in the direction of the furrows. The generally flat or flat upper surface is suitable for hooking products of relatively open woven and non-woven eyelets as used in disposable or limited-use garments. This flat or flat top surface is non-abrasive and smooth to the touch unlike molded hooks that generally have a different apex (eg, on the slopes of the hooks away from a peak in at least two directions). Vertex hook fasteners are less pleasing to the skin, making them less suitable for use in relation to sensitive skin (eg, in a baby diaper).

For use in diapers and similar garments, the capped filament hooks are of uniform height, preferably about 0.10 to 1.3 mm in height and more preferably about 0.2 to 0.5 mm in height. The hooked filament hooks have a density in the backrest preferably of 60 to 1,600 hooks per square centimeter and more preferably of about 100 to 700 hooks per square centimeter. The base portions of the filaments have a diameter adjacent to the heads of the capped filament hooks, preferably 0.07 to 0.7 mm, and more preferably about 0.1 to 0.3 mm. The capped heads project radially beyond the base portions of the filaments on at least one side preferably, on average, about 0.01 to 0.3 mm, and more preferably, on average, about 0.02 to 0.25 mm and have average thicknesses between its outer and inner surfaces (i.e., measured in a direction parallel to the axis of the filaments) preferably from about 0.01 to 0.3 mm and more preferably from about 0.02 to 0.1 mm. The topped heads have a ratio between average diameter (i.e., measured radially of the axis of the topped heads and the filaments) and thickness of the topped head preferably from 1.5: 1 to 12: 1, and more preferably 2.5: 1 to 6: 1. In order to have good flexibility and strength, the backing of the finned filament fastener is preferably a film of 0.02 to 0.5 mm in thickness, and more especially of 0.06 to 0.3 mm in thickness, especially when the fastener is made of polypropylene or a copolymer of propylene and ethylene. For some uses, a stiffer backing could be used, or the backing can be coated with a layer of pressure-sensitive adhesive on its surface opposite the surface with the hooked filament hooks through which the backing could adhere to a substrate. . For most uses of the eyelets and hooks, the capped filament hooks of the capped filament fasteners should be substantially uniformly distributed over the entire surface area of the capped filament fastener, generally in a square, stepped or rectangular configuration. hexagonal. For hermaphroditic uses, the hooked filament hooks are preferably distributed to avoid lateral sliding when they are hooked. The finished filament fasteners of the invention can be produced in long, wide fabrics, which can be rolled up as rolls for convenient storage and shipping. The material of the filament fastener topped in such rolls may have a layer of pressure-sensitive adhesive on the surface of the backing opposite that of the hooked filament hooks, adhesive that can be attached in a detachable manner to the heads of the filament. the filament hooks topped in underlying wraps of the filament fastener material topped in the roll. These rolls do not require a release liner to protect the layer of pressure sensitive adhesive in the roll. The limited area of the heads to which the pressure-sensitive adhesive on the roll adheres keeps the filament fastener material capped in a stable roll form until it is ready for use, and then allows the fastener material be easily unrolled from the roll. Pieces of the desired lengths of the finned filament fasteners can be cut from fastener material and can be secured in adhesive or otherwise to articles such as a fin of a garment to allow the fin to be secured so that it can be secured. detach trial methods 135 degree peel test The 135 degree peel test was used to measure the amount of force required to detach sample of filament mechanical fastener material with head of a sample of fastener material. A 2-inch piece was placed. x 5 in. (5.08 cm x 12.7 cm) of an eyelet test material on a 2-in. Steel panel. x 5 in. (5.08 x 12.7 cm) using a double-coated adhesive tape. The eyelet material was placed on the panel with the transverse direction of the eyelet material parallel to the longitudinal dimension of the panel. A 1 inch band was cut. x 5 in. (2.54 cm x 12.7 cm) of the mechanical fastener to be tested and a 1"mark was placed. (2.54 cm) from both ends of the mechanical fastener band. The band of hooks was then placed centrally over the buttonhole so that there was a 1"contact area. x 1 in. (2.54 cm x 2.54 cm) between the band and the eyelet material and the guide edge of the band was along the length of the panel. The band and laminate of buttonhole material were rolled manually, once in each direction, using a 4.5 pound (1000 grams) roller at a speed of approximately 12 in. (30.5 cm) per minute. Paper was used between regions that did not engage the web and eyelet material to ensure a maximum hook of 1 in. (2.54 cm). Holding the guide edge of the band, the laminate was lightly cut manually approximately 1/8 in. (Hooks) hooking the band elements into the eyelets. The sample was then placed in a release template at 135 degrees. The template was placed in the lower jaw of an Instron ™ Model 1122 tensile tester. Without previously detaching the sample, the guide edge was placed in the upper jaw with the 1"mark. On the lower edge of the gag. At a head speed of 12 in. (30.5 cm) per minute a graphic recorder set at a paper speed of 20 in. Was used. (50.8 c) per minute to record the detachment that was maintained at 135 degrees. An average of the four highest peaks in grams was recorded. The force required to separate the band from the mechanical fastener from the eyelet material was reported in grams / 2.54 cm in width. The reported values are an average of at least five tests. 135 Degree Decay Test The test of detachment by twisting to 135 degrees was performed in a manner similar to the 135 degree peel test except that the sample preparation was different. After the mechanical fastener band was placed on top of the eyelet material on the panel, a 9 Ib (4 kg) weight was placed on top of the laminate. Then the weight was twisted about 0.5 in. (1.3 cm) in one direction, then 0.5 in. (1.3 cm) in the opposite direction. This was done twice during a total of four twists. The twist detachment test was then performed as described above for the 135 degree peel test.

Examples Example 1 A precursor web material having a set of vertical thermoplastic filaments was prepared in a manner similar to that described for Example of PCT Application No. WO 94/23610. The density of the filaments was 900 filaments / inch2 (139 filaments / cm2). The filament height was 25 mils (0.63 mm) and the width or diameter of the filaments was 11 mils (0.28 mm). The thickness of the cloth backing was 4.5 mils (113 microns). The precursor web was prepared from an ethylene-propylene impact copolymer resin (# SRD7-560, obtainable from Union Carbide). The precursor fabric was fed through a contact line formed by two calendering cylinders. The surface of the upper cylinder, which was placed in contact with the distal ends or 'ends of the filaments, had a pattern of structures of peaks and valleys (grooves). (See Figure 3c). The furrows were approximately 1 mil (0.025 mm) deep and 2 mils (0.051 mm) apart. The grooves were oriented in the machine direction (ie, parallel to the circumferential direction of the cylinder, see Figure 3b). The temperature of the upper cylinder was set at 140 ° C, and the temperature of the lower cylinder, which was brought into contact with the cloth backing, was set at 16 ° C. The separation of the contact line was 10 mils (0.25 mm) and the precursor fabric was fed through the contact line once. The pressure of the piston that held the calendering cylinders together was enough to compress the fusion zone. The speed of the line was 3 meters / minute. The resulting capped filament hooks were elongated in the machine direction. The diameter of the topped in the direction of the machine was 24 thousand (0.61 mm) while the diameter of the topped in the transverse direction was 15 thousand (0.38 mm). The height of the topped filaments was 16 mils (0.4 mm). The elongated capped filament fasteners were then tested for the 135 degree peel test. For comparative purposes a "mushroom" round filament top fastener with 900 strands / inch2 (139 strands / cm2), which could be obtained from 3M Company as XMR-4152, was also tested. The eyelet material used for the test was a woven eyelet material called KN-0568 which can be obtained from 3M Company. For the elongated filament hook fastener the detachment test was performed so that the detachment front was perpendicular to the longitudinal axis of the finishes. Release values at 135 degrees for the elongated cap filament fastener averaged 259 grams / 2.54 cm in width. Release values at 135 degrees for round-topped filament fasteners averaged 139 grams / 2.54 cm in width.

Example 2 The same precursor fabric that was used for the Example 1 was used for the preparation of Example 2. The precursor fabric was fed through a contact line formed by two calendering cylinders where the surface of the upper cylinder, which was put in contact with the distal ends or tips of the filaments, had a model of structures of peaks and valleys (grooves) where the grooves were oriented in the transverse direction (ie parallel to the face of the cylinder, see Figure 3a). The furrows were approximately 1 thousand (0.025 mm) deep and were separated at 2 thousand (0-051 mm). The temperature of the upper cylinder was maintained at 141 ° C (as measured with a contact thermocouple) and the lower cylinder was cooled to 17 ° C (as measured with a contact thermocouple). The precursor fabric was fed through the contact line three times. For the first pass the separation of the contact line was 18 mils (0.46 mm); for the second pass, the separation of the contact line was 15 mils (0.38 mm); for the third pass, the separation of the contact line was 12 mils (0.3 mm). The pressure of the piston that held the calendering cylinders together was enough to compress the fusion zone. The speed of the line was approximately 14 meters / minute. The resulting capped filament hooks were elongated in the transverse direction. The average diameter of the topped heads in the transverse direction was 23 thousand (0.58 mm) while the average diameter of the heads topped in the machine direction was 14 mils (0.36 mm). The average height of the topped filaments was 19 mils (0.48 mm). The elongated capped filament fasteners were then tested with the 135 degree twist-off test. The detachment test was performed so that the detachment front was perpendicular to the longitudinal axis of the topped heads. The eyelet material used for the test was a nonwoven eyelet material that was similar to that described as Example 1 in U.S. Patent No. 5,256,231. The twist detachment test was performed in such a way that the detachment front was parallel to the bonding lines of the eyelet material. The 135 degree twist release values for the elongated capped filament hook fastener averaged 775 grams / 2.54 cm in width. For comparative purposes, a round "mushroom" topped filament fastener was also tested. The 135-degree twist-off values for round-topped filament hook fasteners averaged 354 grams / 2.54 cm in width.

Examples 3 to 9 Examples 3 to 9 were prepared to demonstrate how detachment values are affected by the directionality of the capped portions of the elongated capped filament hook fastener. A hook fastener fabric of elongated capped filaments was prepared in a manner similar to that described for Example 2 (headed portions oriented in the transverse direction). Samples of the hook fastener were cut from the fabric at angles of 0o, 15o, 30o, 45o, 60o, 75o and 90o (0o was parallel to the long axis of the topped part, 90o was parallel to the short axis of the topped part or perpendicular to the long axis of the topped part) and were tested for loosening by twisting at 135 degrees. The eyelet material used for the twist-off test was a non-woven eyelet material that was prepared in a manner similar to that described for Example 1 in U.S. Patent No. 5,256,231 except that the carded non-woven fabric used for Eyelet material preparation was made with 6 denier polypropylene fibers. The twist detachment test was performed in such a way that the detachment front was parallel to the joining lines of the eyelet material. The results of the twist detachment are presented in the Table.

Table The results show that the values of detachment due to twisting increase as the detachment goes against the short axis of the topped parts (90 °) to the detachment against the longer axis of the topped parts (0 °).

Example 10 A fastener of elongated capped filaments was prepared in a manner similar to that described for Example 1 except that the surface of the upper calendering cylinder had a pattern of groove structures having grooves with a depth of approximately 2.2 mils (0.056 mm) that were separated by 5.7 mils (0.15 mm). The temperature of the upper calendering cylinder was set at approximately 135 ° C, and the temperature of the lower calendering cylinder was set at approximately 16 ° C. The separation of the contact line was 16 mils (0.41 mm). The precursor fabric was fed through the contact line once at a line speed of 4.6 meters / minute. The resultant elongated capped filament hooks had a diameter of the topped part in the machine direction of 18.6 mils (0.47 mm) and a diameter of the topped part in the transverse direction of 12.9 (0.33 mm). The height of the topped filaments was 19.1 mils (0.49 mm).

Example 11 A hook fastener of elongated capped filaments was prepared as described in Example 10 except that the surface of the upper calendering cylinder had a pattern of groove structures that had grooves with a depth of approximately 0.86 mil (0.022 mm) and were separated at 1.9 mils (0.048 mm). The elongated capped filament hooks had a diameter of the topped part in the machine direction of 19.6 mils (0.50 mm) and a diameter of the topped part in the transverse direction of 14.7 mils (0.37 mm). The height of the topped filaments was 19.7 mils (0.50 mm).

Example 12 A fastener of elongated capped filament hooks was prepared in a manner similar to that described for Example 2 except that the precursor fabric had a filament density of 1600 filaments / in2. (247 filaments / cm2). The height of the filaments was 19 mils (0.48 mm) and the width or diameter of the filaments was 7.8 mils (0.20 mm). The thickness of the backing was 4.2 mils (107 microns). The precursor fabric was fed through the contact line twice. The separation of the contact line was 12 mils (0.31 mm) for the first pass and the separation of the contact line was 9 mils (0.23 mm) for the second pass. The resulting elongated capped filament hooks had a diameter of the part topped in the transverse direction of 16 mils (0.41 mm) and a diameter of the topped part in the machine direction of 11.1 mils (0.28 mm). The height of the finished filaments was 15.8 mils (0.40 mm). Finished filament hook fasteners were tested for 135 degree peel and 135 degree peel off using the same type of nonwoven eyelet material that was used for testing in Example 1. The two peel tests were performed from so that the detachment front was perpendicular to the long axis of the finished parts. Release values at 135 degrees for the elongated capped filament hook fastener averaged 210 grams / 2.54 cm in width. The hook fasteners of rounded topped filaments having the same density of filaments also had an average of 210 grams / 2.54 cm in width. The 135 degree twist detachment values for the elongated capped filament hook fastener averaged 854 grams / 2.54 cm in width. Fasteners of rounded topped filament hooks having the same filament density had an average of 880 grams / 2.54 cm in width. Finished filament hook fasteners were also tested for 135 degree peel and 135 degree peel off using the same type of nonwoven eyelet material that was used for testing in Example 2. The two peel tests were performed in such a way that the detachment front was perpendicular to the long axis of the topped parts of the hook fastener and parallel to the link lines of the eyelet material. Release values at 135 degrees for the fastener of elongated capped filament hooks averaged 1426 grams / 2.54 cm in width. The hook fasteners of rounded topped filaments having the same density of filaments also had an average of 1876 grams / 2.54 cm in width. The 135 degree twist release values for the elongated capped filament hook fastener averaged 290 grams / 2.54 cm in width. The hook fasteners of rounded capped filaments having the same density of filaments had an average of 149 grams / 2.54 cm in width.

It is noted that in relation to this date the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property

Claims (16)

1. A method for finishing hook heads in a backing characterized in that it comprises: a) providing a fabric having a cloth backing with a set of substantially vertical projections, each formed at least in part by a base portion 10 of substantially vertical filament, the fabric having a first thickness; provide a contact line that has at least a first surface element 15 heated and at least one second opposing surface element defining a separation having a compression zone defined by a first inlet separation width and a second separation width 20, wherein the first width of separation is substantially equal to, or less than, the first thickness of the fabric, the second width of separation being substantially less than the first thickness of the fabric; C) providing the at least one heated surface element of at least one set of beak and groove structures extending longitudinally in at least one first direction in the compression zone, wherein the average spacing between the structures of adjacent peaks is less than the average width of the filament base portions immediately 10 adjacent to a final filament portion or a hook head, and the at least one set of peak and groove structures extends longitudinally at a distance at least equal to the distance 15 average between the base portions of adjacent vertical filaments; Y d) move the fabric along the path of the fabric in, and through, the compression zone 20 in a second direction such that at least one upper portion of the set of substantially vertical projections is preferably deformed by the surface element heated in the at least one The first direction defined by the at least one set of peak and valley structures.

2. The method according to claim 1, characterized in that there are two or more sets of peak and groove structures.

3. The method according to any of claims 1-3, characterized in that the average peak-valley depth (groove) of the at least one set of peak and groove structures is from 5 to 500 microns and from 2 to 40 micron structures. Grooves contact and deform each hook head or portion of the end of the filament.

4. The method according to any of claims 1-3, characterized in that at least some of the vertical projections are provided with a distal end portion of the filament, at least some of the end portions being directionally deformed as hook heads in the compression zone by at least one set of peak and groove structures.

5. The method according to any of claims 1-4, characterized in that at least one set of peak and groove structures extends continuously through at least one heated surface element in said at least one first direction. in the compression zone for at least that portion of the compression zone that comes into contact with the vertical projections.

6. The method according to any of claims 1-5, characterized in that at least one first direction forms an angle with respect to the second direction and the heated surface moves at a first speed in the second direction and the fabric moves to substantially the same first speed in the second direction.

7. The method according to any of claims 1-5, characterized in that at least a first direction is substantially parallel with respect to the second direction and the heated surface moves at a first speed in the second direction and the fabric moves to a second speed in the second direction.

The method according to any of claims 1-7, characterized in that the compression zone has two or more heated surface elements, at least one heated surface element has no peak and groove structures.

9. The method according to any of claims 1-8, characterized in that the vertical projections are formed of a thermoplastic resin.

10. The method according to any of claims 1-9, characterized in that the first steering angle with respect to the second direction varies along the length of the grooves.

11. The method according to any of claims 1-10, characterized in that the separation width decreases substantially linearly in some portion of the compression zone.

12. A mechanical fastener formed by hook structures having topped hook heads, mechanical fastener characterized in that it comprises a backrest with vertical hook elements, the hook elements having a filament base portion and a topped hook head, characterized in that less a portion of the hook heads have a dimensional relationship between length and width of at least 1.1 and the hook heads have at least one thick region and at least one thin region extending in the longitudinal direction of the head of hook.

13- The mechanical fastener according to claim 12, characterized in that there are 4 to 20 thick regions in the topped hook heads.

14. The mechanical fastener according to claim 12, characterized in that the topped hook heads have a substantially flat flat upper surface.

15. The mechanical fastener according to any of claims 12-14, characterized in that the vertical hook elements are formed by a thermoplastic ream wherein the backrest is a film formed by the same thermoplastic ream and the topped hook heads have a dimensional relationship of at least 1.5, wherein the topped hook head has the shape of an elongated mushroom-shaped portion, a T-shape or a J-shape, and the base portion of the filament extends at an angle from 80 to 100 degrees of backup.

16. The mechanical fastener according to any of claims 12-15, characterized in that the hook structures of the topped mechanical fastener have 0.1 to 1.3 mm in height, have a density of from 60 to 1600 hook structures topped per cm2, base portions of the filaments have a diameter adjacent to the topped heads of from 0.07 to 0.7 mm and the topped heads project beyond at least one side of the base portions of the filaments by at least 0.01 to 0.3 mm on average and the average thickness of the topped hook head is from 0.01 to 0.3 mm.