Title of Invention

IMPROVEMENTS IN OR RELATING TO MAKING EASY TEARABLE LAMINATE

Abstract

A method of slitting a laminate web to form laminate elements having tear properties, said method comprising the following steps, [i] providing a slitting station consisting of [a] a cutting assembly consisting of at least one cutter wheel mounted in a, cutter holder; [b] a hardened roller acting as an anvil for the cutter wheel; [c] arrangement for urging the cutter wheel against the hardened roller; [ii] providing means to rotate the hardened roller; [iii] providing means to draw the laminate web from a master roller through the slitting station and onto take up rewind spools; [iv] drawing the laminate web through the slitting station; [v] rotating the hardened roller [v] urging the cutter assembly towards the rotating hardened roller by applying urging pressure on the cutter assembly to urge the cutter wheel on the laminate web operatively on the rotating hardened roller to slit the laminate web by crush cutting into laminate elements; and [vi] rewinding the slit laminate elements on take up spools.

Full Text

FORM-2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE Specification (Section 10; rule 13) A METHOD AND APPARATUS OF SLITTING A LAMINATE WEB TO FORM LAMINATE ELEMENTS HAVING TEAR PROPERTIES THE PAPER PRODUCTS LTD. of L.B.Shastri Marg, Majiwade, Thane 400 601, Maharashtra, India, an Indian Company 13 AUG 2004 THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED:- This invention relates to a method and apparatus of slitting a laminate web to form laminate elements having tear properties. This invention particularly relates to a laminate, which is used for packing different type of products. The laminate is folded and sealed to form what is normally called a 'pouch'. Laminates have been used as an integral part of packaging to pack a product, chiefly for two reasons- -A laminate in the form of a pouch or other package protects a product element placed therein from the harsh environment. - laminates can be printed over and also serve the function of conveying the details of the product packed therein such as, the details of the manufacturing of the product , any particular instructions that the manufacturer or the body governing the manufacturers wishes or the seller of the product wishes to convey to the end user. Typically, a laminate used for packaging consists of two or more layers of a synthetic polymeric material in the form of film, paper or a metal foil. The thickness of a laminate can be from 10 to 400 micron or even more. The laminate structure is selected to suit the product it has to pack. Laminates can be unprinted or printed. Unprinted laminates are basically used for protecting the element in the pack from harsh environment. The printed laminate not only protects the element in the pack but it also gives information about element contain in laminate as mentioned above. Laminates are intensively used for packing various products. Specific uses of laminates are laminated pouches for coffee; soup; ready to eat food etc. One problem commonly associated with laminated packages is that it is difficult to tear open these packages once sealed for the purposes of accessing its contents. Form fill and seal machines are used to convert laminates into pouches which are sealed after product filling for forming packed products. These packed products are used by end users, by accessing the product from the laminate pouch by either simply cutting the pouches with the help of knives or scissors. Another method of achieving tearability is to provide a weakness zone in the package. However, such weakness zones are not always satisfactory and besides they entail one additional step in the manufacturing process thus increasing costs. An object of this invention is to provide a laminate that can be easily torn by hand without use of knife or scissor. The laminate in accordance with this invention consist of a few layers of synthetic polymer material in form of a film, paper or metal foil. The number of layers and thickness of layer may change as per requirement of product. These layers are joined together by gluing or any other process. Another object of this invention is to provide a laminate which is tearable with comparative easy when the laminate is converted into a package form or even otherwise. The laminates envisaged in accordance with this invention consist of two or more plys of typical thicknesses ranging from 10 to 400 microns or more and includes both printed and imprinted laminates. Laminates are typically manufactured by an extrusion process and are stored for use on winding workstations on master rolls. For actual use the laminates are unwound from the master rolls and slit into small coils for end use. This slitting is conventionally done with a razor blade arrangement or with the help of a shear knife in which top and bottom cutters are used and the laminate sheet is slit while passing through the sheer cutters. The applicants have discovered a new form of slitting laminates from master rolls in which crush cutters are used for slitting the laminate sheet emanating from the master roll. In this slitting method developed by the inventors, the laminate is cut by crushing action of of a cutting wheel assembly against a hardened anvil.. The applicants have found that if the laminate is slit by the crushing knife in accordance with this invention, the laminate is imparted with easy tear properties in a direction perpendicular to the direction of traverse of the crushing cutting cutter wheel, i.e. in a direction perpendicular to the slit. According to this invention there is provided a method of slitting a laminate web to form laminate elements having tear properties, said method comprising the following steps, [i] providing a slitting station consisting of [a] a cutting assembly consisting of at least one cutter wheel mounted in a cutter holder; [b] a hardened roller acting as an anvil for the cutter wheel; [c] arrangement for urging the cutter wheel against the hardened roller; [ii] providing means to rotate the hardened roller; [iii] providing means to draw the laminate web from a master roller through the slitting station and onto take up rewind spools; [iv] drawing the laminate web through the slitting station; [v] rotating the hardened roller [v] urging the cutter assembly towards the rotating hardened roller by applying urging pressure on the cutter assembly to urge the cutter wheel on the laminate web operatively on the rotating hardened roller to slit the laminate web by crush cutting to form laminate elements ; and [vi] rewinding the slit laminate elements on take up rewind spools According to another aspect of this invention there is also provided apparatus for carrying out the method of claim 1 comprising a slitting station consisting of [a] a cutting assembly consisting of at least one cutter wheel mounted in a cutter holder; [b] a hardened roller acting as an anvil for the cutter wheel; [c] arrangement for urging the cutter wheel against the hardened roller; [ii] geared rotating means to rotate the hardened roller; [iii] drawing means to draw the laminate web from a master roller through the slitting station and onto take up rewind spools; [v] urging means to urge the cutter assembly towards the rotating hardened roller to slit the laminate web by crush cutting into laminate elements and [vi] rewinding means to rewind the slit laminate elements on rewind take up spools. The urging means may consist of means to apply hydraulic or pneumatic pressure on the cutting assembly. Typically the cutter assembly comprises wheels made of hardened steel mounted on at least one shaft using bearings at the center and being free to rotate on a central axis, said cutters being mounted in a cutter housing by means of an adjustable holding arm . Typically, the cutter wheels are round or cylindrical. In accordance with a preferred embodiment of this invention, a lever is provided for raising or lowering the cutter assembly onto or away from the hardened roller. The invention will now be described with reference to the accompanying drawings, in which Figure 1 illustrates a schematic view of the slitting arrangement in accordance with this invention; Figure 2 is a schematic view of the gear assembly and the roller assembly for the slitting arrangement of figure 1; Figure 3 shows an isometric view of the arrangement of figure 1. Figure 4 shows a side view of the slitting station Figure 5a and 5b show the details of the cutter assembly for the slitting arrangement. Referring to the drawings, a method of slitting a laminate web to produce an easy tear laminate element is described and illustrated. The laminate web designated by the reference numeral 6 generally indicated in the figures of the accompanying drawings is slit by at least one crushing cutter wheel 5 having a cutter wheel blade 10 by urging it with crushing strength on the laminate web 6 against a rotating hardened roller 1 which acts as an anvil. The laminate web is unwound from a spool of a master roller [not shown or marked in the drawings]. The hardened roller 1 acts as an anvil on which the cutter crushingly slits the laminate web 6 to form laminate elements 6a and 6b which is then wound on bottom and top rewind spools 2 and 3 respectively. The driving gear train is represented by the reference numeral 7. The cutters as particularly seen in the assembly in figure 5 are in the form of wheels 5 made of hardened steel and may typically be round or cylindrical. The cutters are mounted on at least one shaft 12 using bearings 14 at the center and are typically free to rotate on a central axis. The cutters are typically mounted in a cutter housing 4 by means of an adjustable holding arm 16. The upper edge of the housing is adjustable be means of the lever 9 with respect to the fixed lower edge 11. The actuator handle/lever 9 can be actuated to raise or lower the cutting wheel towards or away from the hardened roller 1. The cutter wheel is provided with a sharp edge 10 which can be raised or lowered to provide the crushing and cutting action. A typical machine will have a bank of such cutter wheels or cutter assemblies and a plurality of take up rewind spools Pressure is typically applied on the laminate by the cutter assembly hydraulic or pneumatic means 8 as particularly seen in figure 4 and the sharp edge 10 of the cutter wheel 10 working against the hardened rollers 1 on which the laminate is supported by crush cutting. The hydraulic or pneumatic means may typically be at least one conduit 13 supplying pressurized fluid from a manifold 15. It is found that the laminate slit in accordance with the method of this invention has easy tear properties in a direction perpendicular to the slit. A possible explanation for the easy tear properties is that the crush slitting process caused the development of micro cracks in the laminate edge due to the pressure of the cutting blade applied on the laminate. These micro cracks develop in a direction perpendicular to the direction of the slit. While considerable emphasis has been placed herein on the structures and structural interrelationships between the component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principals of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. We Claim: [1] A method of slitting a laminate web to form laminate elements having tear properties, said method comprising the following steps, [i] providing a slitting station consisting of [a] a cutting assembly consisting of at least one cutter wheel mounted in a, cutter holder; [b] a hardened roller acting as an anvil for the cutter wheel; [c] arrangement for urging the cutter wheel against the hardened roller; [ii] providing means to rotate the hardened roller; [iii] providing means to draw the laminate web from a master roller through the slitting station and onto take up rewind spools; [iv] drawing the laminate web through the slitting station; [v] rotating the hardened roller [v] urging the cutter assembly towards the rotating hardened roller by applying urging pressure on the cutter assembly to urge the cutter wheel on the laminate web operatively on the rotating hardened roller to slit the laminate web by crush cutting into laminate elements; and [vi] rewinding the slit laminate elements on take up spools. [2] A method of slitting a laminate web to form laminate elements having tear properties as claimed in claim 1, in which the step of urging is done hydraulically. [3] A method of slitting a laminate web to form laminate elements having tear properties as claimed in claim 1, in which the step of urging is done pneumatically. [9] Method of slitting a laminate web to form laminate elements having tear properties as described herein with reference to the accompanying drawings. [10] Apparatus for slitting a laminate web to form laminate elements having tear properties as described herein with reference to the accompanying drawings. Dated this 16th day of June , 2004

Documents:

589-mum-2003-cancelled pages(16-06-2004).pdf

589-mum-2003-claims(granted)-(13-8-2004).doc

589-mum-2003-claims(granted)-(13-8-2004).pdf

589-mum-2003-correspondence(13-8-2004).pdf

589-mum-2003-correspondence(ipo)-(16-6-2003).pdf

589-mum-2003-drawing(13-8-2004).pdf

589-mum-2003-form 1(6-6-2003).pdf

589-mum-2003-form 13(13-8-2004).pdf

589-mum-2003-form 18(4-5-2005).pdf

589-mum-2003-form 2(granted)-(13-8-2004).doc

589-mum-2003-form 2(granted)-(13-8-2004).pdf

589-mum-2003-form 3(6-6-2003).pdf

589-mum-2003-form 4(16-6-2004).pdf

589-mum-2003-form 5(16-6-2004).pdf

589-mum-2003-power of attorney(7-11-2000).pdf

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