FLEXIBLE TAPE WITH EMBEDDED CUTTING FILAMENT

Abstract

The present invention provides a filament-bearing tape. The filament-bearing tape extends longitudinally and comprises a flexible substrate having a first edge and a second edge parallel to the first edge, and having top and bottom surfaces. The tape also has a filament that is encompassed in the top surface of the substrate, parallel to the edges of the substrate.

Claims

1. A filament-bearing tape extending longitudinally and comprising a filament and a flexible substrate having a first edge and a second edge parallel to the first edge, and having top and bottom surfaces, wherein the filament is encompassed in the top surface of the substrate, parallel to the edges of the substrate.

2. The filament-bearing tape of claim 1, wherein the bottom surface of the substrate is coated with an adhesive.

3. The filament-bearing tape of claim 1, wherein the flexible substrate is a foamed elastomeric compound.

4. The filament-bearing tape of claim 3, wherein the flexible substrate is flexible cellular foam or polyethylene foam.

5. The filament-bearing tape of claim 1, wherein the flexible substrate is natural or synthetic rubber or silicone rubber.

6. The filament-bearing tape of claim 1, an upper surface of the filament not covered by the substrate so that the upper surface is exposed without extending above adjacent portions of the upper surface of the substrate.

7. The filament-bearing tape of claim 1, wherein an upper surface of the filament is minimally covered by a thin portion of the top surface of the substrate.

8. The filament-bearing tape of claim 1, wherein the top surface of the substrate has a profile configured to decrease the area of the top surface contacting a flat lower surface of a film or tape when the film or tape is placed over the top surface of the substrate.

9. The filament-bearing tape of claim 8, wherein the top surface of the substrate has a serrated profile.

10. A roll of the filament-bearing tape of claim 1.

11. A filament-bearing tape extending longitudinally comprising a filament and a flexible substrate comprising extruded material, and having a first edge and a second edge parallel to the first edge, and having top and bottom surfaces, wherein the filament is embedded in the substrate, parallel to the edges of the substrate, and proximate to the top surface of the substrate so that the filament is releasably held in place by the substrate so as not to restrict the removal of the filament when the filament is pulled upwards and through the top surface of the substrate.

12. The filament-bearing tape of claim 11, wherein the bottom surface of the substrate is coated with an adhesive.

13. The filament-bearing tape of claim 11, wherein the flexible substrate is a foamed elastomeric compound.

14. The filament-bearing tape of claim 12, wherein the flexible substrate is a foamed elastomeric compound.

15. The filament-bearing tape of claim 13, wherein the flexible substrate is flexible cellular foam or polyethylene foam.

16. The filament-bearing tape of claim 11, wherein the flexible substrate is natural or synthetic rubber or silicone rubber.

17. The filament-bearing tape of claim 12, wherein the flexible substrate is natural or synthetic rubber or silicone rubber.

18. The filament-bearing tape of claim 2, wherein the flexible substrate is a foamed elastomeric compound.

19. The filament-bearing tape of claim 18, wherein the flexible substrate is flexible cellular foam or polyethylene foam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a top perspective view of an embodiment of a foam tape with a cutting filament encompassed by the foam carrier with an adhesive coating on the lower side.

[0024] FIG. 2 is an end view of the tape of FIG. 1.

[0025] FIG. 3 is an end view of the tape of FIG. 1 further including a release coating on the upper side.

[0026] FIG. 3a is an end view of the tape of FIG. 1 further including adhesive on the upper side and a release liner applied over the top of the adhesive.

[0027] FIG. 4 is a top perspective another embodiment of a foam tape with a serrated profile upper surface and a cutting filament encompassed by the foam carrier and an adhesive coating on the lower side.

[0028] FIG. 5 is an end view of the tape of FIG. 4.

[0029] FIG. 6 is an end view of the tape of FIG. 4 further including multiple cutting filaments encompassed in the foam and multiple reinforcement filaments embedded in the foam.

[0030] FIG. 7 is an end view of the tape of FIG. 4 adhered to a surface where a film has been applied over the surface and the tape, where the filament has been removed from the tape, cutting through the film.

[0031] FIG. 8 is an expended view of a portion of FIG. 7 showing the break in the coating caused by removal of the cutting filament.

[0032] FIG. 9 is an end view of the tape of FIG. 4 with a masking film attached to the top of the tape, where the tape is adhered to a surface, a coating has been applied over the surface and the tape, and the filament has been removed from the tape, cutting through the coating.

DESCRIPTION OF THE INVENTION

[0033] The present invention is a new form of edge trimming tape that is well suited for trimming coatings, such as polyurethane, paint and epoxies; films such as vinyl and polyester, in addition to other various substrates such as paper, cork, felt, etc.

[0034] The following elements are numbered in the drawings.

[0035] Item no. 1: Extruded Profile with Releasably Secured Cutting Filament—Flexible Cellular Foam. The profile may be square or round or any other shape. This may alternatively be referred to as a substrate or carrier, which may comprise polyethylene foam or other foamed elastomeric compound. The tape preferably utilizes a foam rubber carrier (such as EVA foam—a polymer of Ethylene Vinyl Acetate) or Polyethylene Foam within which a filament is releasably encompassed or incorporated. The foam rubber carrier is thicker than the filament and has physical properties that enable the carrier to more easily conform to irregular surfaces and bend laterally and axially, along and around smaller diameter radiuses and compound curves significantly better than prior art tapes. The carrier may be manufactured as an extruded film of foamed polymeric material with a square profile that is designed to be held in a machined groove or it may have a rectangular profile with an adhesive on one or more surfaces, similar to single-coated or double-coated foam tape. The substrate may be made from natural or synthetic rubber or silicone rubber. The carrier is stretchable and compressible with a thickness greater than the filament. The thickness of the carrier may typically be 20 to 30 mils (0.020 to 0.030 inches or 0.050 to 0.075 cm). The unique flexibility of foam due to its physical properties provides a stretchable and compressible carrier and solves the problem of positioning the filament-bearing tape laterally on a surface around tight bends and acute angles. The high elongation of the foam also contributes to an increased effectiveness of the pressure sensitive adhesive (PSA) to hold the filament-bearing carrier flat to a surface where tight bends are made.

[0036] Item no. 2: Uncoated Surface of Extrusion—The extrusion may be made without an adhesive or release coating.

[0037] Item no. 3: Pressure Sensitive Adhesive (PSA) Coating—In preferred embodiments, where the tape may be used as a masking tape, the tape includes adhesive on the bottom side of the substrate. The adhesive may comprise acrylic adhesive. The adhesive may be a rubber or silicone adhesive. It may be, for example, about 1 mil (0.001 inches or 0.0025 cm) thick, comprising acrylic adhesive. In other embodiments, adhesive may be applied to both the top and bottom surfaces of the substrate and a release liner applied to one or both adhesive layers.

[0038] Item no. 4: Cutting Filament—The filament may be, for example, a 0.010 inch (0.025 cm) diameter metal wire cutting filament. In preferred embodiments, the size may range from 0.002 inch (0.0051 cm) diameter to 0.020 inch (0.051 cm) diameter. In some embodiments, the filament may be made of an elastic synthetic material, such as a monofilament nylon wire. In some embodiments, the filament may be a braided thread made from a plurality of fine strands. The material and thickness of the filament are selected based on the application for which the associated tape is intended to be used, such that the filament has sufficient tensile strength to cut the coating material or film it is intended to be used with when such coating is dried or cured. In preferred embodiments, the filament does not protrude beyond the carrier surface so that the finished product has a uniform flat surface across the entire width permitting the typical rewind process onto a paper core or spool without the problems associated with an irregular surface created by the filament being held on the surface of the carrier instead of within the surface of the carrier. In reference to rewinding the tape onto a spool, a key advantage of a uniform profile, whereby the tape does not have a filament attached to the exterior of the carrier, of this invention is that it provides for a level winding of the tape onto a roll, eliminating the difficulty of rewinding the tape in either a flat or traverse wound method on a core or spool.

[0039] Item no. 5: Release Liner—The release liner is a thin layer made from material selected to be readily removable after contact with an adhesive.

[0040] Item no. 6: Serrated Profile—A means for self-winding the extrusion in roll form whereby the adhesive coating on the opposite (bottom) side will not stick to the top side. As will be evident to skilled persons, many profiles could be made to achieve the same result.

[0041] Item no. 7: Reinforcement Filaments—For the purpose of increasing the tensile and tear strength of the extrusion without significant loss of flexibility.

[0042] Item no. 8: Film—illustration of film being layered over the extrusion and cut by pulling the filament upwards and through the film.

[0043] Item no. 9: Application Surface—The surface to which the film is being applied.

[0044] Item no. 10: Coating—Illustration of a coating applied to a surface and being cut by pulling the filament upwards through the coating.

[0045] Item no. 11: Masking Film—Additional masking film applied to the back (top surface) of the extrusion used to protect the surface not to be coated.

[0046] Item no. 12. Release Coating—A silicone or other release coating applied to the top (upper) surface of the foam tape carrier.

[0047] Item no. 14. Foam Carrier.

[0048] The new invention allows for the filament 4 to be encompassed by, or embedded in or enveloped by, the substrate and releasably held in place by the extruded material without preventing the removal of the filament 4 when pulled upwards and through the material 8, 10 to be cut. Preferably the substrate substantially surrounds the filament other than possibly a small portion of the filament, and holds the filament in position by substantially encapsulating the filament within the substrate material. The filament may be positioned within the carrier during the extrusion process of manufacturing the film/substrate or in a post-extrusion process in which the filament is incorporated in the substrate and encompassed by it.

[0049] The filament may be incorporated within the substrate at the moment of extrusion. Alternatively, as will be evident to one skilled in the art, a suitable film could be used and in a secondary process, the filament 4 incorporated by forming a cavity in the film and afterwards incorporating the filament 4 or by cutting an opening in the surface of the film and as a secondary process, inserting the filament 4 into the film substrate.

[0050] It is preferred to form the top surface of the extrusion 6 with a profile that decreases the surface area such as the embodiment shown in FIGS. 4-9 that has a serrated profile 6. Not only does such a profile permit self-winding without a release coating on the top surface, but it also improves the flexibility of the product.

[0051] The filament 4 is shown as being slightly exposed such that a minimum force is required for release of the filament 4 from the extrusion. In some embodiments, the filament is coated so that it is not bonded to the extrusion material.

[0052] An extruded film has other advantages in being able to use multiple filaments positioned precisely within the extrusion, for example as shown in FIG. 6. The width and thickness of the extrusion are also important advantages over the use of a PSA tape product.

[0053] It is key to the invention that the cutting filament is releasably retained within or releasably held by the substrate (carrier) itself without the use of an adhesive or other means of holding the filament in place. The filament may not be completely enveloped to be retained or held in place but in some embodiments it may be totally engulfed by the substrate.

[0054] In prior art filament-bearing masking tapes, a cutting filament is applied to and positioned upon a surface, and an adhesive is used in one way or another to hold the filament within or against the carrier. In some prior art as discussed above, the filament is enveloped within the adhesive and carrier by folding the adhesive tape around the filament. In prior art filament-bearing masking tape, the cutting filament is held in place by partially or completely embedding the filament in the adhesive.

[0055] The new invention relies on the carrier itself being thick enough to substantially surround the filament. The invention may also be made by making a cut into the surface of foam tape and inserting a cutting filament, although this is not preferred. For example, such a method would be especially difficult if one wanted to use a rubber carrier or similarly flexible carrier.

[0056] In the manufacture of the invention, the method of making the cooling/forming roll with a serrated surface with fine v-grooves, grooves serve two purposes. The first is to guide the filament in a precise position in the bottom of the “V” and the second is to allow the extruded molten material from the extruder to flow over and substantially around the filament so as to retain the filament within the rapidly cured substrate. Preferably, the filament is slightly exposed beyond the outer surface of the substrate for easy removal, but only slightly exposed so that the final product still has a flat, level top and bottom surface for rewinding on a roll without having to work with rewinding a substrate with an irregular surface. The cutting filament of prior art cutting filament tape inventions creates an uneven and irregular surface because the filament is held on the outside surface of the carrier substrate.

[0057] The new invention addresses the main issue that exists in cutting vinyl and other polymeric films. There is nothing better than using a fine, small diameter metal wire to make clean smooth cuts through the film. However, it is very difficult to attach a fine metal wire to a very thin adhesive coating on a thin tape substrate, especially when using double-side (coated) tape is not practicable for the application. It is much easier to attach a fiber filament, such as a Kevlar thread. The 3M product referred to as Knifeless Tape™ is related to patents on the positioning of a (fiber) filament adhesively retained at or near the center of the bottom, adhesive side of the tape so that the thin flexible tape carrier can be applied and positioned around curves whereby the tape can be bent similarly for inside and outside curves.

[0058] The limitations of typical prior art adhesive tapes include the relative lack of ability to apply and curve the tape on a flat surface while trying to facilitate curves and bends. The edges of the tape tend to buckle or pucker and lift away from the surface if the curve is too tight for the tape. That is easily demonstrated when attempting to apply masking tape on a flat surface while trying to make the tape adapt to a curve or bend. The new invention described herein does not rely on the location of the filament for making tight inside or outside turns but instead relies on the substrate having the ability to stretch and compress without the adverse effect of the carrier lifting away from the surface while bending the substrate around curves. The new invention, having a cellular foam carrier holds the advantage of accomplishing superior positioning ability over most single and double-coated adhesive tapes that do not incorporate a foam substrate carrier.

[0059] The invention also provides the ability to extrude almost any profile imaginable around the cutting filament. Another use for the invention is to make a profile that does not necessarily require the application of an adhesive to its surface. In the mold industry where parts are cast in a closed mold, there is typically an extra material referred to as flash around the perimeter of the molded part. The flash is the material that is allowed to escape the mold when completely filled. It is another use of the invention to machine a groove along the outer perimeter of the mold surface in which can be placed a strip of the extruded profile containing a cutting filament. Many parts such as automotive dashboards and seating products have a flashing that must be trimmed after removing from the mold. By having a cutting filament positioned along the precise trim line of the flashing, it is practical to pull the cutting filament from the groove to cut and remove the flash material. The filament-bearing silicone rubber extrusion with a profile that matches the groove prevents any of the molded material from entering the positioning groove during the molding process and would then be replaced with each cycle of use.

[0060] In a manufacturing process such as trimming a coating applied to a surface such as an automobile surface, the manufacturer of the automobile may design the area to be coated with a recess along the perimeter for the purpose of holding the filament carrier in place.

[0061] The present tape is novel in that the cutting filament does not rely on an adhesive means for attaching or effectively holding the filament to the carrier but instead utilizes the carrier to incorporate the filament within itself by encompassing or partially encompassing the filament.

[0062] The new invention is ideally suited for incorporation of a small diameter metal filament because the metal wire can be effectively held securely in place. In contrast, in prior art tapes, attempting to hold any filament securely in place on the typical PSA tape carrier by means of imbedding the filament partially or completely in the adhesive layer continues to be a problematic factor of such embodiments.

[0063] Another feature of the invention is the use of relatively soft, low-tensile strength cellular foam as the carrier whereby the user can easily access and remove the cutting filament by peeling back the foam from the filament using only their fingers, eliminating the requirement of a special tool or cutter.

[0064] The invention is also ideally suited to hold a synthetic fiber as a cutting means and is a preferable means of doing so over the prior art.

[0065] Another feature of the invention is that the cutting filament does not cause the carrier to lift from the surface when the filament is pulled for the purpose of cutting the coating or film. The invention shows that the filament is positioned within the top side of the carrier so that the carrier remains attached to the surface and does not instantly lift from the surface as the filament is pulled.

[0066] When the cutting filament is pulled from any of the existing products/art, the filament must either be pulled through the carrier that holds the filament in place or the filament must be pulled around the edge of the carrier, both methods producing a significant strain on the cutting filament to escape before starting to begin cutting the film or coating and causing the tape substrate to lift or deflect and thereby causing the film or coating to lift or deflect prior the final cut being completed. The present invention provides a means of the filament being in physical contact with film or coating for a more efficient and clean cutting process that does not disturbs or lift the film or coating during the cutting process.

[0067] It should be understood that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are only examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention as will be evident to those skilled in the art. That is, persons skilled in the art will appreciate and understand that such modifications and variations are, or will be, possible to utilize and carry out the teachings of the invention described herein.

[0068] Where, in this document, a list of one or more items is prefaced by the expression “such as” or “including”, is followed by the abbreviation “etc.”, or is prefaced or followed by the expression “for example”, or “e.g.”, this is done to expressly convey and emphasize that the list is not exhaustive, irrespective of the length of the list. The absence of such an expression, or another similar expression, is in no way intended to imply that a list is exhaustive. Unless otherwise expressly stated or clearly implied, such lists shall be read to include all comparable or equivalent variations of the listed item(s), and alternatives to the item(s), in the list that a skilled person would understand would be suitable for the purpose that the one or more items are listed.

[0069] The words “comprises” and “comprising”, when used in this specification and the claims, are used to specify the presence of stated features, elements, integers, steps or components, and do not preclude, nor imply the necessity for, the presence or addition of one or more other features, elements, integers, steps, components or groups thereof.

[0070] The scope of the claims that follow is not limited by the embodiments set forth in the description. The claims should be given the broadest purposive construction consistent with the description and figures as a whole.