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US 20030183326A1 (19) United States (12) Patent Application Publication (10) Pub. N0.: US 2003/0183326 A1 O’C0nn0r (43) Pub. Date: Oct. 2, 2003 (54) METHOD FOR MANUFACTURING (52) US. Cl. ......................... .. 156/187; 156/259; 156/229 PRESSURE SENSITIVE ADHESIVE TEAR TAPES (57) ABSTRACT . Amethod for manufacturin ressure sensitive adhesive tear (76) Inventor: Lljlgvrence O’Connor’ Nokomls’ FL tape for use in tearing an igerwrap material includes pro ( ) viding a Web of a polymeric material Which is biaXially Correspondence Address: oriented, slitting the Web into a plurality of side by side ADE & COMPANY continuous tapes, drawing each continuous tape longitudi 1700_360 MAIN STREET nally to effect additional longitudinal orientation of the tape WINNIPEG MB R3C3Z3 (CA) and Winding each tape into a separate spool. In a second ’ separate process, the tapes side by side are unWound and (21) APPL NO: 10/113,933 passed through a printing line Where a coating of a pressure sensitive adhesive is applied to the ?rst tape surface and a (22) Filed; Apt; 2, 2002 coating of a release agent is applied to the second tape surface to provide a release action relative to the adhesive. Publication Classi?cation Each continuous tape With the adhesive coating thereon is Wound into a respective cylindrical tape spools for supply to (51) Int. Cl.7 ................................................... .. B32B 31/00 the packaging line. CONTROL \ l5 \9 20 (2t Patent Application Publication Oct. 2, 2003 Sheet 1 0f 2 US 2003/0183326 A1 FIG. I " CONTROL \15 Patent Application Publication Oct. 2, 2003 Sheet 2 0f 2 US 2003/0183326 A1 F192 / _ ~ [/42 US 2003/0183326 A1 Oct. 2, 2003 METHOD FOR MANUFACTURING PRESSURE Which is then draWn in machine direction to effect orienta SENSITIVE ADHESIVE TEAR TAPES tion of the extruded layer. The amount of draW possible is limited by the tendency of the material to ?brillate beyond [0001] This invention relates to a method for manufactur a predetermined extension. After the longitudinal draW is ing pressure sensitive adhesive tear tapes. effected, the Web is draWn in the transverse direction by a tentering frame Which increases the total orientation up to a BACKGROUND OF THE INVENTION level to give the required mechanical properties of strength [0002] Tear tapes for use in tearing an overWrap packaging and resistance to elongation. This material is knoWn as material are used in many different packaged products. The biaxially oriented. This Web is then slit into a plurality of tear tape is adhesively attached to the inside surface of the longitudinally continuous side-by side tapes Which can be overWrap material betWeen the overWrap material and the coated With adhesive in a process subsequent to the slitting packaged product. as in the O’Connor patent set out beloW or can be coated in Web Width With the adhesive prior to slitting as in the May [0003] This system has been in effect for many years and patent above. HoWever, the mechanical limitations of the for the majority of those years the tear tapes Were formed of orientation process limit the amount of orientation, Which a simple mono-axially oriented plastics material supplied can be effected so that the resultant product is of reduced individually from supply spools. In some cases the plastics strength and increased thickness relative to the theoretical material carries a colorant so that the tape is of a different optimum. color from the overWrap material. On line With the overWrap material, an adhesive is applied to the tape after it is [0011] When the pressure sensitive adhesive onto the sheet unWound from the supply spool and prior to its attachment in Web Width, the sheet is slit in a preliminary slitting process to the overWrap material. Thus the spooled supply of the tear into a plurality of primary Webs, each of Which is then tape is free from adhesive and free from any release coats Wound into a fresh supply roll. The Width of the individual and is thus a simple product to manufacture formed solely by primary rolls must be matched With the Width of the intended the base plastics material itself. tapes and the number of those tapes in order that the number of tapes slit from the Web equal the limited number of [0004] One technique for manufacturing a tear tape of this spooling Wind-up heads available. Each primary roll is then type involves extruding the plastics material, casting the slit in a subsequent operation to form the requisite number extruded material in a Wide sheet form onto a chilling of tapes, folloWing Which, the tapes are individually Wound surface so as to form a cast sheet, slitting the cast sheet into into separate traverse Wound spools each on a respective one a plurality of individual tapes, longitudinally draWing the of the spooling Wind-up heads. This process of slitting and tapes so as to provide longitudinal or mono-axial orientation reWinding into primary rolls does not add value to the of the tapes and Winding the tapes into a traverse or helically product so that it is simply a Wasted cost. In addition, the Wound spool for supply to the packaging line. repeated unrolling and re-rolling of the material can degrade [0005] As the formed tape in its Wound condition com the adhesive by exposing the adhesive to the air and by the prises only the plastics material itself, it is possible to readily effect of repeated contact With the release coating. Yet recycle trim Waste formed during slitting of the tapes from further, each slitting action requires a further loss of trim an initial Web and any Waste generated during transfer of Waste from the edges of the primary rolls so that the trim Winding from one spool to the next. Such materials can Waste can in total constitute a signi?cant proportion of the simply be fed back to the extruder and re-extruded With the original Web Width at a signi?cant cost. feed material. [0012] This process for manufacturing the tape has a [0006] Tapes of this type have been manufactured by a number of signi?cant disadvantages. number of manufacturers for up to 40 years and are Widely [0013] Firstly it is necessary to effect slitting of the ?lm accepted. through the layer of adhesive Which is applied thereto. Slitting through adhesive is Well knoWn to be problematic in [0007] In the late 1980’s a neW product Was introduced in Which the tape in its spooled form is supplied With a pressure that the adhesive attaches to the slitting knife and can form sensitive adhesive already applied onto one surface of the balls of adhesive Which can break aWay and interfere With tape. This product had the signi?cant advantage that it Was the travel and processing of the tapes. no longer necessary to apply adhesive on line With the [0014] Secondly the trim Waste, Which is necessary at each packaging system thus avoiding the dif?culty of feeding the slitting process, causes high losses in the proportion of total adhesive onto the tape Which may be stopping and starting Waste relative to the quantity of ?nished material leading to With the packaging line. signi?cantly increased material cost. Where the trim Waste [0008] The pressure sensitive adhesive tape became there carries adhesive material, it is impossible to carry out a fore adopted to some extent in the industry but still the recycling process. majority of tear tapes are of the simple type Where the [0015] Thirdly in order to complete a full spool of the tear adhesive is applied on line. tape, it is necessary to splice together end to end the primary [0009] One disadvantage of the pressure sensitive tear tape rolls as they are unWound, since the length of the tear tape Which has reduced its acceptance is the signi?cantly on the spool is considerably longer than the length of the sheet on the primary roll. In the ?nished spool, therefore the increased cost of the product. To some extent this increased cost arises due to the dif?culty of manufacture. tear tape may have a series of splices through its length and these splices are difficult to carry out due to the presence of [0010] Some tear tapes are manufactured by extruding a the release coat and are often functionally problematic in the Web of polypropylene, polyester or other suitable material, packaging line on Which the tear tape is to be used. This US 2003/0183326 A1 Oct. 2, 2003 compares unfavorably With conventional non-adhesive tear [0026] providing a Web of a polymeric material tapes Which are usually splice free. Which is biaXially-oriented; [0016] The additional slitting of primary rolls described [0027] continuously forWarding the Web; above and also the splicing necessary for the individual primary rolls provides a signi?cant additional cost in the [0028] passing the Web as it is forWarded through a process both of labor and equipment thus dramatically slitting assembly arranged to slit the Web at trans increasing the cost of the product relative to the conven versely spaced positions into a plurality of side by tional non-adhesive tear tape. side continuous tapes, each having ?rst and second [0017] Despite these dif?culties, the above manufacturing tape surfaces and tWo tape edges; process has been used Widely by a number of manufacturers [0029] after slitting, draWing each continuous tape and continues to be the pre-eminent technique Which is used longitudinally to effect additional longitudinal ori for manufacturing of these tapes. entation of the tape; [0018] One example of a tape of this type manufactured by [0030] after draWing, applying a coating of a pressure this technique is described in US.