Composite hook and loop fasteners, methods of their manufacture, and products containing them

ES 2 371 604 T3

DESCRIPTION

Composite Hook and Loop Clasps, Manufacturing Methods, and Products Containing Them

Background of the invention

This invention relates to composite hook and loop fasteners, methods of their manufacture, and products containing them. Such a closure is known, for example from US-A-5,669,120.

A typical composite hook and loop closure is produced by taking a preformed hook and loop material and overlapping and pinning the two materials together along their edge margins or completely overlapping one another. Fixation is usually done by ultrasonic welding, heat fusion or adhesive bonding. This step of attaching the preformed hook and loop material to form the composite closure adds additional cost to the manufacturing process. Hook and loop materials can also be rolled in situ during hook component formation.

One particular application for an improved composite closure, discussed in more detail below, is as a wrap clamp for closing bags. An inexpensive bag clamp normally used in retail stores comprises a wire covered with paper. The wire clamp is wrapped around an open end of a bag and the ends of the wire are twisted together to close the bag. Another common type of bag clamp is a clip clamp that consists of a piece of plastic with an opening. A collected open end of the bag is pushed through the side of the opening to close the bag. Other closures include strings and tapes and closure arrangements employing adhesives or removable hooks.

Wire clamps and clip clamps are often used in retail stores where items such as bakery products, fresh produce, dry goods, nails, etc. they are placed in a bag and sold by weight or by unit. The consumer usually stores these products in the bags. The clamps can be opened and closed many times before the bag is empty. There is a need for low cost reliable repeat use closures for this and many other applications.

Summary of the invention

A composite hook and loop closure in the form of an elongated strip includes a loop component, a hook component permanently attached to the loop component, and a support layer disposed on one face of the winding clamp in a distinct region. . The support layer is used to permanently fix the winding clamp to a bearing surface. One end of the loop component is available to surround an object to be wound and engage the closure elements of the hook component. The loop component has a self-supporting network of entangled fibers, the fibers forming both a sheet-like body and loose, hook-engageable loops extending from at least one surface of the body, and the hook component has closure elements. that extend from a common base.

In general, in one embodiment, the invention provides a winding clamp in the form of an elongated strip. The winding clamp has an elongated loop component having a network of fibers that form both a sheet-shaped body and hook-engageable loops extending from at least one surface of the body, a hook component permanently attached to a first loop component end, the hook component comprising a synthetic resin base and a matrix of looped closure elements integrally molded with and extending from a first surface of the base, and a support layer permanently attached to a second surface of the base bets on the closing elements, to permanently fix the winding clamp to a bearing surface. A second end of the loop component is available to surround an object to be wound and engage the closure elements of the hook component.

Implementations of this embodiment of the invention may include one or more of the following features. The loop component network can be non-woven and specifically a non-woven needle network. Nonwoven needle net can weigh less than approximately 2 ounces per square yard (68 grams per square meter). The nonwoven web may be in a stretched, stabilized state. The loops of the loop component may extend from loop structures, and at least some of the loop structures may each have a common elongated stem portion extending from the web from an associated knot and multiple loops extending extend from the trunk part. The loop component may have a resin encapsulated edge margin of the hook component, and a remaining resin-free portion of the hook component. The edge margin can be approximately 10% of the area of ​​the loop component. The loop component may have a resin encapsulated entire face of the hook component. The loop component can have two sides 2

ES 2 371 604 T3 opposite widths, and the loops can extend from both sides. The hook component can be shorter than the loop component, if measured along the winding clamp, and the support layer can longitudinally overlap the hook component and can be arranged on one side of the opposite winding clamp. to the closure elements. The closure elements of the hook component may be mushroom or hook shaped. The hook component can be disposed at one end of the elongated winding clamp, and the hook-shaped closure elements can extend to the other end of the winding clamp. The base of the hook component may include an integral extension gap of closure elements, for overlapping the loop component and for face-to-face attachment. The backing layer can be a pressure sensitive adhesive or a synthetic resin. A removable release liner can cover the pressure sensitive adhesive layer. The release liner may longitudinally overlap the loop component such that a portion of the release liner is exposed for gripping.

According to another embodiment of the invention, a winding clamp has an elongated hook component having a synthetic resin base and an array of closure elements extending from a first surface of the base, a loop component permanently attached to a first end of hook component, the loop component having a network of fibers that form both a sheet-shaped body and hook-engageable loops extending from at least one first surface of the body, and a support layer permanently attached to a second surface of the component body loop to permanently fix the winding clamp to a bearing surface. A second end of the hook component is available to surround an object to be wound and hook the hookable loops on hooks of the loop component. The hook component may be in a stretched state.

According to another embodiment of the invention, a bag has an open end and an elongated, strip-shaped wrap clamp according to this invention, permanently attached to an outer surface of the bag to close the open end. The wrap clamp is permanently attached to the outer surface of the bag at a discrete region along the length of the wrap clamp. One end of the loop component is available to surround the open end of the bag to secure the bag in a closed state. The wrap clamp can be permanently attached to the bag by a layer of pressure sensitive adhesive or a synthetic resin. The bag can be made of synthetic resin or paper.

According to another embodiment of the invention a sheet-like composite contact closure includes a loop component having a self-supporting nonwoven network of entangled fibers, the fibers forming both a sheet-shaped network body and loose loops, hookable on hooks, extending from at least one surface of the net body, and a hook component having a synthetic resin base with which the loop hooks are integrally molded. The resin of the hook component extends at least partially below the loop component and encapsulates the fibers of the net body of the loop component.

Implementations of this embodiment of the invention may include one or more of the following features. The loop component may have a resin encapsulated edge margin of the hook component, and a remaining resin-free portion of the hook component. The edge margin can be approximately 10% of the area of ​​the loop component. The loop component may have an entire resin encapsulated face of the hook component. The loops of the loop component may extend from a common side of the sheet-like contact closure. The loops of the loop component may be disposed on one side of the sheet-like composite contact closure opposite the hooks of the hook component. The fibers of the loop component may be encapsulated in the resin of the hook component and the loop component may comprise regions that are more encapsulated by resin than other regions.

According to another embodiment of the invention a sheet-shaped composite contact closure includes a sheet-like loop component having a network of fibers that forms both a sheet-like body of the sheet-like network and loops engageable on hooks that interlock. extend from at least one surface of the net body and a sheet-shaped hook component comprising a synthetic resin base with which the looping hooks are molded in such a way solidarity. An edge region of the hook component is permanently attached to a first edge of the loop component and fibers from the first edge of the loop component are resin encapsulated from said edge region of the hook component. The loop component has a second edge, opposite said first edge, substantially free of resin from the hook material.

According to another embodiment of the invention there is provided a method for manufacturing the elongated strip-shaped winding clamps of this invention. The method includes the following steps: providing a longitudinally continuous sheet of finite width loop material, the loop material having loops extending from at least a first surface. Permanently bonding a longitudinally continuous strip of plastic hook material to the loop material to form a laminated material, the hook material at least partially overlapping the loop material across the width and with a width significantly less than the width of the loop material , the hook material having a strip-shaped base and closure elements

ES 2 371 604 T3 molded integrally with and extending from the base in the form of a strip. Apply pressure sensitive adhesive to a predetermined region on one side of the laminate opposite the fasteners. Cutting the laminate material to form the wrap clamps, each wrap clamp having a part of the loop material, a part of the hook material, and a layer of the adhesive.

Implementations of this embodiment of the invention may have one or more of the following characteristics. For a wrap tie having a removable release liner covering the adhesive layer, the method further includes, prior to the cutting step, applying a longitudinally continuous release liner to the laminate to cover the adhesive. The cut at least pierces the loop material and the base of the hook material to define longitudinal edges of the individual winding clamps, and leaves the parting liner longitudinally continuous. The cut wrap clamps can be rolled over the continuous release liner for later release. The hook material can be attached to the loop material by ultrasonic welding, heat welding, or pressure sensitive adhesive. The bonding step may also include continuously feeding the loop material through a defined interface between a rotary cast roll and a pressure roll, the rotary cast roll defining a plurality of fixed cavities around its periphery for casting. the closing elements of the hook material, while continuously feeding molten resin into the mold roll under conditions that cause the resin to fill the cavities of the mold roll and form the hook material, such that pressure at the contact surface binds the loop material to the material Hook. Molten resin can be fed into the casting roll at multiple discrete regions along the roll, thus forming multiple parallel strips of laminated hook material for the loop material. Following the bonding step and prior to the cutting step, the laminated material is longitudinally cut into multiple longitudinally continuous strips, each strip including hook material, loop material, and adhesive. The loop material can be fed through the contact surface in the form of multiple parallel strips, while the hook material is formed to fill the gaps between adjacent strips of hook material at the contact surface.

According to another embodiment of the invention there is provided a method of manufacturing the elongated strip-shaped winding clamps of this invention. The method includes the following steps: providing a longitudinally continuous sheet of finite width loop material, the loop material having loops extending from at least a first surface of the loop material. Provide a longitudinally continuous strip of plastic hook material, the hook material having a width significantly less than the width of the loop material, the hook material having a first surface with fastener elements integrally molded with and extending from the first surface, and a second surface, opposite the first surface, having a pressure sensitive adhesive layer. Bonding the hook material and the loop material along their length, the loop material overlapping a longitudinal edge of the hook material and leaving the adhesive layer exposed by the loop material. Cut the laminate material to form the wrap clamps, each wrap clamp having a part of the loop material, a part of the hook material, and a layer of the adhesive.

According to yet another embodiment of the invention there is provided a method of making a sheet-shaped composite contact closure. The method includes the following steps: providing a longitudinally continuous sheet of finite width loop material, the loop material having a self-supporting nonwoven web of entangled fibers, the fibers forming both a sheet-like web body and loose loops engageable in hooks extending from at least one surface of the net body, said loop material having a substantially constant fiber density along its width. Permanently bonding a longitudinally continuous strip of plastic hook material to the loop material to form a laminated material, the hook material having a synthetic resin strip-shaped base with closure elements integrally molded with and extending therefrom and wherein said synthetic resin of the hook component base extends at least partially through below the loop component and encapsulates fibers from said loop component network body. Cutting the laminated material to form the composite material contact closures, each composite contact closure having a part of said loop material, and a part of said hook material.

According to yet another embodiment of the invention there is provided an apparatus for making the elongated strip-shaped winding clamps of this invention. The apparatus includes a cooled rotary forming roll defining a plurality of fixed inwardly extending closure member cavities at its periphery; a pressure roll positioned to co-operate with the forming roll to define a contact surface, the pressure roll having an outer surface for supporting a continuous sheet of loop material fed to the contact surface; and an extrusion nozzle positioned to direct a continuous flow of molten resin toward the forming roll under conditions that cause the resin to fill the cavities of the closure member and form a continuous layer of resin against the forming roll, such that the resin layer is attached to the loop material by pressure at the contact surface, to form a laminate material. The apparatus further includes an applicator arranged to apply a longitudinally continuous layer of pressure sensitive adhesive to a distinct region on one side of the laminate opposite the

ES 2 371 604 T3 closing elements; a guide arranged to direct a longitudinally continuous release liner to cover the applied layer of adhesive; and a blade arranged to cut in a transverse direction through the laminated material to form individual winding clamps.

According to yet another embodiment of the invention there is provided a method of releasably securing a container in a closed state. The method includes providing a winding clamp in accordance with this invention; permanently adhering the winding clamp to a surface of the container; wrapping one end of the loop component around the container; and engaging the closure members of the hook component with the loops of the loop component to maintain the container in a closed state.

Other features and advantages of the invention will be apparent from the following description of embodiments, and from the claims.

Brief description of the drawings.

Figure 1 is a perspective view of a wrap tie having an elongated loop component overlapping one end of a short hook component and adapted for permanent attachment to a bag or the like.

Figure 1A is a perspective view of a bag having the wrap clamp of Figure 1 attached to its surface.

Figure 1B is a side view of a winding clamp having loops on both sides of an elongated loop component.

Figure 1C is a side view similar to that of Figure 1B, of a winding clamp having an elongated loop component, an end portion of which overlaps the entire rear surface of a hook component.

Figure 1D is a side view of a winding clamp to which a hook component is attached in the middle of an elongated loop component.

Figure 1E is a side view of a winding clamp in which an elongated stretched hook component overlaps one end of a short loop component.

Figure 1F is a side view of a winding clamp in which the hook strip is attached face to face with the loop strip.

Figure 2A is a photograph of a preferred nonwoven loop material for use as a loop component, at 50X magnification.

Figure 2B is a schematic view of the face of the nonwoven loop material shown in Figure 2A.

Figure 2C is a sketch of the nonwoven loop material illustrating bundles of loop fibers extending from a fibrous mat.

Figure 3 is a side view of a braided winding clamp according to the invention.

Figures 4A and 4B are enlarged perspective views of parts of a hook fastener and a stretched hook fastener, respectively.

Figure 5 illustrates an apparatus for forming and joining components of a winding clamp.

Figure 6A is a perspective view of a part of the apparatus of Figure 5 for forming the preform product of Figure 7, while Figure 6B is a view taken on the plane 6B-6B of Figure 6A.

Figure 7 illustrates a network made up of attached hook and loop bands formed with the apparatus of Figures 5, 6A and 6B.

Figure 8 is a perspective view of four loop and hook segments formed by cutting the net shown in Figure 7.

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Figure 9 is a plan view of a hook and loop segment that has been pierced cut.

Figure 10 is an enlarged side view of the loop and hook segment, taken along line 10-10 in Figure 9.

Figure 11 is a cross-sectional view of the interface between the loop and hook segments, taken along line 11-11 in Figure 10.

Figure 12 is an enlarged side view of area 12 in Figure 10.

Figure 13 illustrates the reciprocal ultrasonic welding of bands of loop and hook material to form a wrap clamp blank.

Figure 13A illustrates the rotary ultrasonic welding of bands of hook and loop material to form a wrap clamp preform.

Figure 14 illustrates the thermal fusion of bands of hook material and loop material to form a wrap clamp preform.

Figure 15 is a schematic illustration of an apparatus that distributes winding clamps from a carrier sheet.

Figure 15A is a schematic illustration of area A in Figure 15.

Figure 15B is a schematic illustration of an automatic label dispensing apparatus.

Figure 16A is a side view of overlapping winding clamps.

Figure 16B is a schematic illustration of a dispenser box for the overlapping wrap clamps of Figure 16A.

Figure 17 is a schematic illustration of an application of a winding clamp as a pipe support for a wall.

Description of achievements

Referring to FIG. 1, a wrap clamp 100 shows an elongated strip of nonwoven loop material 110 attached to a short strip of hook material 120.

The nonwoven loop material strip has a first surface 114 with hook-engageable loops 112 and a second relatively smooth surface 116. The strip of hook material 120 has a first surface 122 with integrally molded fastener elements 126 and a second smooth surface 124. The closure elements can be shaped like mushrooms or hooks. The hook-shaped closure elements extend into the loop material. The smooth surfaces of the loop and hook strips overlap a distance d and are attached at joint 128 so that the loops and hooks extend in opposite directions from the winding clamp. A layer 130 of pressure sensitive adhesive covers the remaining portion of the smooth surface 124 of the hook strip 120. For a face-to-face fixation of the hook and loop strips (Figure 1F), that is, a fixation of the surface of the loop strip having the loops to the surface of the hook strip having the hooks, the part The base of the hook strip 120 has an integral extension 129 without hooks to overlap the loops of the loop strip 110. The pressure sensitive adhesive layer 130 is covered with a release liner 132, such as silicon coated paper. The release liner 132 longitudinally overlaps the loop component such that a portion of the release liner is exposed for gripping. In one example, the clamp is 0.5 inches wide, dimension w, the loop strip is 3 inches long, dimension 1, the hook strip is 0.75 inches long, dimension 11, and the overlap area 128 it is 0.4 inches long, dimension d, all components having the same width w. The thickness of the loop material can range from about 0.150 inches to 0.0100 inches, and the thickness of the hook material can range from about 0.100 inches to 0.010 inches.

Referring to Figure 1A, the wrap clamp of Figure 1 is attached to an open end of a bag by the adhesive layer. The elongated nonwoven loop strip is wrapped around the bag opening and the free end of the loop strip is secured to the hook strip by engaging the loops with the hooks. The wrap clamp can be pre-closed and integrated with the bag, for example during bag manufacture, or it can be applied to the bag at the time of use, removing the separation layer and

ES 2 371 604 T3 pressing the adhesive component against the bag material. The bag can be made of synthetic resin or paper. In some examples the wrap clamp may have, instead of the pressure sensitive adhesive layer, a synthetic resin layer that can be thermally melted to the bag surface.

In such applications where products are considered disposable after a single use, the loop material only needs to withstand a relatively small number of latch cycles (eg, 3 to 5) during the life of the product. These are referred to as "low cycle" applications. Loop products in this category can advantageously be made from needled textile material having needle-like loops on one or both sides. In certain cases, the material is in a permanently stabilized and stretched state, having been stretched to increase its area in excess of 100%, as much as 150% or more from its needle condition. A preferred drawn and needled material is formed of cut polyester yarns of between about 18 and 4 denier, preferably 6 denier.

Other applications, such as strapping or bundling, may require hook-on loops to withstand a greater number of cycles and higher stresses. These relatively high-stretch and "high cycle" applications are generally preferably achieved by using woven or warped material or by looping with fibers of higher denier (or higher tenacity) than is suitable for lower performance conditions. Loop products in this category can be prepared by stretching an appropriate needle loop fabric in the stretch range of 50 percent to 100 percent, for example, followed by stabilization.

For certain applications, specially treated loop material can be used in a winding clamp. For example, in a bag that contains an electronic device and needs to dissipate static electricity, non-woven loop material impregnated with carbon or stainless steel can be used. Carbon or stainless steel fibers can also be mixed with staple fiber to form a nonwoven loop material that dissipates static electricity. A double-sided non-woven loop material can be used in a wrap clamp that, regardless of whether it is braided, can be closed with the hook.

Additional configurations of a winding clamp include but are not limited to the following: loop strip 110 has loops on both surfaces 114 and 116 (FIG. 1B), loop strip 110 overlaps and is attached to the entire smooth surface 124 of hook strip 120, adhesive layer 130 being closely attached to side 114 loop of the strip (FIG. 1C), hook strip 120 is attached to the middle of loop strip 110 (FIG. 1D), and an elongated hook strip 120, which may be of formed and stretched material, is attached to a short loop strip 110 (Figure 1E).

In preferred embodiments, the nonwoven loop material 110 (FIG. 1) is very thin, but still self-supporting, and has relatively free fibers that form loops that extend from one side or both sides of a mat of continuous or tangled fibers. In preferred embodiments, the nonwoven loop material 110 comprises a needled fabric of staple fibers that have been stretched longitudinally and transversely to form a fabric of the form depicted in Figures 2A and 2B.

In such a textile material, the individual fibers of the mat do not follow a defined pattern as in a woven product, but rather extend in various directions within the plane of the textile mat. The loops that extend from the loop product are the same fibers that comprise the mat but extend beyond the general mass of the mat, out of the plane of the mat, generally from associated 180 knots, in the form of trees 250 loops well anchored (Figure 2C).

As shown photographically in Figure 2A, and in the diagram of Figure 2B, in relatively low density fiber regions of a preferred mat, a substantial number of the fibers in the loop material mat 110 are taut (ie that is, they are not loose, regionally straight), and extend between the knots 180 of the loop fabric. The taut fibers 182 have been straightened by applied tension in at least one direction in the plane of the textile mat 170, while the knots have been produced by slippage and agglomeration produced during the application of stretching forces to the non-textile material. needle tissue.

The knot density of the sample shown in the photograph was determined to be approximately 180 knots per square inch by counting the number of knots visible within a given square area. The knots themselves are fairly tight, made up of several monofilament fibers, and are interconnected by the taut fibers seen running between them. Between knots, the fine fiber mat is not very dense and is pure enough to allow images to be easily seen through. For low cost applications, the fabric preferably weighs less than about 2 ounces per square yard (68 grams per square meter).

In this particular embodiment, the fibers of the mat are held in their taut, straight state by means of a water-based acrylic binder (not visible in the photograph) applied to the side of the mat opposite the loops to bind the fibers of the mat. mat in its straight state to stabilize the surface dimensions of the textile material, and to hold

ES 2 371 604 T3 the loops at their associated knots. The binder generally ranges from 20 to 40% of the total weight of the textile material and in presently preferred embodiments represents approximately one third of the total weight of the loop component. The resulting fabric is dimensionally stable and strong enough to be suitable for further processing by conventional fabric handling techniques. Although the textile material has a slight stiffness, like a starched felt, the stiffness can be mitigated when desired by softeners or mechanical work.

As seen in FIG. 2C, loops 112 extend from freestanding clusters of loop fibers that extend from fibrous mat 170. Clusters 250 having multiple monofilament loops 112 extending from a common, elongated, substantially vertical trunk 252 termed "loop trees." Each loop shaft 250 extends from a corresponding node 180 in which the loops of the cluster are anchored. Interstices between individual filaments in the trunk portion 252 of each tree or at the base of each bush, and at each node 180 provide trajectories for drainage of the liquid binder, under the influence of the surface tension of the liquid binder, to provide rigidity and additional localized resistance. Most importantly, the density of the clusters in the plan view is very low, leaving enough space between the “branches” of neighboring trees to accommodate hooks and deviated loop material during docking.

Referring to Figure 3, the flexibility of the nonwoven material 110 allows it to be twisted multiple times and closed on the hook fastener strip 120. Although there are loops on only one side of the strip, there are loops that can be hooked into all quadrants of the braid to ensure engagement with the hook component. In addition, the loops around the cut edges of the loop strip are oriented in line with the fibrous mat 170, making the edge hook engageable.

A hook strip 120 compatible with the loop material is used. For a nonwoven loop material made of staple polyester fibers having a denier of 6, a hook may be of the designation CFM-29, available from Velcro USA Inc. of Manchester, New Hampshire, USA. CFM-29 hook has hooks only 0.015 inches (0.38 mm) high. Especially when the hook component is the elongated component as shown in Fig. 1E, the hook strip can be a stre tched hook product. Referring to Figures 4A and 4B, when a hook product is subjected to lateral stretching, the material of the base web 150 decreases in thickness, from the original thickness t0 of Figure 4A to the reduced thickness t1 of Figure 4B. Consequently, the surface density of the closure elements is reduced. For example, with hook elements of a type having a conventional height of about 0.035 inches and a spacing lo of about 0.050 inches along the rows, beginning with a spacing Wo of the rows of about 0.025 inches and ending With a spacing W1 from Figure 4B of about 0.100 inches, the surface density changes by a factor of 4, from approximately 800 fasteners 11 per square inch to approximately 200 fasteners per square inch. Starting with higher hook densities, higher final densities can be achieved to suit particular application hook needs, while still maintaining low cost.

The product of Figure 1 can be economically formed by the method and apparatus illustrated in Figure 5. The extruder barrel 308 melts and forces molten plastic 310 through a slot-shaped die 312. The extruded plastic enters the contact surface 314 between the base roll 316 and the mold roll 318 which contains mold cavities shaped to form the hooks of a hook and loop type strip-shaped hook fastener component well. known. The strip closure material formed on the contact surface 314 travels around the periphery of the mold roll 318 to the mold roll 320, which helps to pull the finished product 300 from the pattern roll, and from it to a device. winding, not shown.

For more details on the general operation of the apparatus of Figure 5, the reader is referred to US Patent 5,260,015 issued to Kennedy, et al., Which discloses laminated materials made with loop materials.

There are many possible methods of feeding the nonwoven sheet material to the forming section of the hook forming device. In one example, shown in Figures 6A and 6B, several transversely spaced bands of nonwoven material 350 are inserted around the periphery of the base roll 316 and enter the contact surface 314 at the same time as the molten plastic 310 comes into contact. the contact surface in the regions between the bands of loop material. The slot-shaped nozzle has alternating open nozzle gaps and protrusions, the gaps being arranged to provide molten resin that fills the gaps 352 between the bands of nonwoven loop material and to produce limited overlap of the resin and bands of nonwoven material tissue (Figure 6B), to form the joints 128. The edge margins of the bands of nonwoven material are closely joined with the edge margins of the molten resin with which the bands of the hook fasteners 354 are integrally formed. The bond is formed by encapsulating the fibers of the loop material with the

ES 2 371 604 T3 cast resin of the hook material. In this way, a composite material structure of joined alternating bands of loop component and hook component is formed.

In one example, a net includes (figure 7), starting from the left, a 3-inch wide strip of nonwoven loop, a one-and-a-half-inch wide strip of hook material, a 6-inch wide strip of nonwoven loop, one and a half inch wide strip of hook material, and one 3 inch wide strip of nonwoven loop. The alternating nonwoven and hook strips partially overlap, being joined at joints 128. The overlap areas are for example 0.4 inches wide. After forming, the net is passed through a cutter where it is cut longitudinally at the midpoints A and C of the hook segments, and at the midpoint B of the 6-inch loop segment. This results in four continuous length composite webs, each comprising a narrow band of hook material joined to a relatively wide band of nonwoven loop material (Figure 8).

In the next stage, each of the four nets passes through a coating line in which a pressure sensitive adhesive is applied to the back of the hook strip material, followed by a stage in the A release liner is placed on the adhesive layer.

At that point, each of the four continuous webs is pierced (die-cut) along lines 400 through the loop and hook side, but not through the parting liner 132, as shown. shown in Figures 9, 10, and 12, to form a series of elongated bag clamps. The direction of the punch 400 is perpendicular to the longitudinal axis 402 of the composite web, which coincides with the direction of the machine. Figure 11 shows a cross section of the net along the indicated direction 11-11.

An alternative way to manufacture the winding clamp is to ultrasonically seal respective preformed bands of hook and loop material. The two materials are cut to the appropriate width and their edges are overlapped and ultrasonically welded in a reciprocating ultrasonic welder, as shown in Figure 13, or a rotary ultrasonic welder, as shown in Figure 13A. The back of the hook material is coated with pressure sensitive adhesive prior to welding.

Another way to manufacture the wrap clamp is to thermally melt overlapping edge margins of preformed bands of hook and loop materials. Thermal fusion is performed with two rotating wheels 160 and 162, shown in Figure 14. Both rotating wheels are heated and may have a knurled pattern on them. The wheels come into contact and trap the area to be joined, which in this case is the area of ​​overlap between the edges of the loop and hook bands. The heated wheels melt the hook resin and melt it in and around the fibers of the nonwoven loop, thereby forming a bond between the margin portions of the two bands. The mechanics that surround the fiber with the molten resin, and then solidified, provides the necessary bond strength.

Different types of resin can be used to form either the hook material or the non-woven material. In certain preferred cases, as mentioned, the nonwoven material is made of polyester fibers and the hook material of polyethylene. The hook and loop material preferably differ in their thermal properties. For example, polyethylene melts at a lower temperature than polyester and thereby allows for thermal fusion of the hook resin around the polyester fiber of the loop material, to form a strong mechanical bond with dimensional stability.

The adhesive for layer 130 is preferably a pressure sensitive type adhesive. In some cases, layer 130 may be a synthetic resin suitable for thermal fusion onto a substrate.

Winding clamps carried by a common release liner 202 can be wound onto a roll 210. Winding clamps 206 have an end 208 attached to the release liner with the pressure sensitive adhesive and a free end 209. Roll 210 can be fed to a conventional labeller 200, shown schematically in Figure 15. The release liner is arranged to pass under an acute angle 212 around a release plate 204, in which direction is reversed. The parting liner is flexible and can easily change direction. However, the wrap clamp has a certain amount of stiffness that causes the edge of the wrap clamp 207 not to follow the gap liner 202 around the peel plate 204, and protrude at the point where the liner of separation reverses its direction (Figure 15A). In this way, the release plate automatically separates the winding clamp from the release liner. The wrap clamp can either be indexed or dynamically placed in a movable bag on a bagging machine that produces polyethylene bags. Automatic label distribution in a movable bag is shown in Figure 15B. The leading edge 217 of the movable bag 218 encounters a photoelectric cell 216. The photoelectric cell can be a light emitting diode. The photoelectric cell 216 sends a signal to the label dispenser 200 and the dispenser accelerates and transports the winding clamp 206 toward the movable bag 218.

ES 2 371 604 T3

When the winding clamp 206 reaches a predetermined location 219 on the bag 218 and while the winding clamp is still connected to the separation liner 202, a tamping roll 214 presses the edge 207 of the winding clamp 206 onto the bag 218 . Winding clamp 206, bag 218, and release liner 202 continue to move at the same speed, while tamping roll 214 presses the winding clamp onto the bag. Once the wrap clamp is completely released from the release liner and attached to the bag, the release liner stops moving as the bag continues to move away from the dispenser region. The process is repeated again when the next bag approaches the dispenser area and encounters the photoelectric cell 216. The advancement of the winding clamps can be controlled by a separate sensor (not shown) to increase accuracy.

When the support layer 130 is made of synthetic resin, the tamping roll 214 is heated to thermally melt the winding clamp on the bag.

In another embodiment, the winding clamps 206 may overlap one another (FIG. 16A), with one end 226 of each clamp releasably attached and one end 224 free. The overlapping winding clamps can be placed in a distributor box 220 (FIG. 16B). The distributor box has an opening 222, which allows the free ends 224 of the winding clamps to be pulled successively from the box.

Other features and advantages of this invention may include one or more of the following. The net in Figure 7 can be coated first with the pressure sensitive adhesive and then passed through the cutter where it is cut lengthwise to form the hook and loop segments. The very low thickness of both the nonwoven loop material and the hook material, together with their low cost and good closing performance, make the winding clamp a particularly useful component of many products. Winding clamps can be used, for example, to close a plastic bag as described above (Figure 1A), to secure pipes or other construction material (Figure 18), to bundle cables and to secure bundled cables, etc.

Other features and advantages of the invention may be realized, as defined by the scope of the appended claims.