EP0042586A1 - Verfahren zum Schneiden und Perforieren von Kunststoff-Folie - Google Patents

Verfahren zum Schneiden und Perforieren von Kunststoff-Folie Download PDF

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Publication number
EP0042586A1
EP0042586A1 EP81104658A EP81104658A EP0042586A1 EP 0042586 A1 EP0042586 A1 EP 0042586A1 EP 81104658 A EP81104658 A EP 81104658A EP 81104658 A EP81104658 A EP 81104658A EP 0042586 A1 EP0042586 A1 EP 0042586A1
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EP
European Patent Office
Prior art keywords
perforating
blade
plastic film
teeth
density polyethylene
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP81104658A
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English (en)
French (fr)
Inventor
Ernest Harold Roberts
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Union Carbide Corp
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Union Carbide Corp
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Publication date
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Publication of EP0042586A1 publication Critical patent/EP0042586A1/de
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
    • B65D31/16—Bags or like containers made of paper and having structural provision for thickness of contents of special shape
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
    • B26F1/18—Perforating by slitting, i.e. forming cuts closed at their ends without removal of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D29/00—Sacks or like containers made of fabrics; Flexible containers of open-work, e.g. net-like construction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B70/00—Making flexible containers, e.g. envelopes or bags
    • B31B70/14—Cutting, e.g. perforating, punching, slitting or trimming

Definitions

  • the present invention relates to a process for cutting or perforating sheets of plastic film material, especially as part of a process for making flexible plastic film packaging materials. More particularly, the invention relates to a process for making plastic film packaging bags and in a preferred embodiment, to a process for making continuous strips of interconnected, but separable, plastic film packaging bags including the step of perforating the plastic film material with a perforating blade having improved service durability.
  • the present invention is especially useful in making packaging bags composed of low pressure-low density polyethylene film.
  • a known process for forming continuous and interconnected but. separable plastic film packaging bags includes the steps of extruding a tube of plastic film material, such as polyethylene, by a tubular blown film extrusion process and advancing the tube through a bag-making machine wherein the advancing tubular film material is heat-sealed across its width at spaced longitudinal intervals and perforated across its width at the same intervals to allow later separation into individual bags.
  • the resulting plastic bags have a variety of packaging uses, such as for garments, trash, produce, meat, and the like.
  • the bag-making machine (such as those available from Gloucester Engineering Co.) is provided with shuttling means to momentarily stop the tube advance for the sealing and perforating operations; however, apparatus is also known which travels along with the advancing tube to seal and perforate same without the necessity of momentarily stopping the tube advance.
  • the resulting continuous strip of interconnected and separable plastic bags may be rolled for dispensing later or the bags may be separated and stacked by methods and apparatus known in the art.
  • Single-ply plastic film wrapping sheets, in continuous strips of interconnected and separable sheets or separated sheets, may be made by a similar process by starting with a single layer of plastic film or sheet material.
  • the perforating is usually performed by forcing a serrated-type blade through the plastic film tube.
  • Such perforating blades are commercially available in various configurations and are typically composed of a flat steel body having teeth along one edge thereof. The configuration of the teeth depends, in part, on the type and size of bag being made and the plastic film material of which it is formed. Those skilled in the art are well aware of the considerations governing the selection of a perforating blade for such applications. As ah example, in a process for making low density polyethylene produce bags in a Gloucester Engineering Model 418 bag machine, a 10-inch long perforating blade composed of No. 1095 carbon steel and having 40 teeth along one edge thereof, may be employed. Each tooth is chamfered on one side as a result of a sharpening operation to thereby provide a cutting edge.
  • Such plastic film packaging bags and sheets have been made of various types of thermoplastic film materials, including low- and high-density polyethylene, polypropylene and the like.
  • low density polyethylene is perhaps the most important of the thermoplastic packaging films, accounting for a significant portion of the total usage of such films in packaging
  • Low density polyethylene possesses a unique combination of properties essential for broad end use utility and wide commercial acceptance in the packaging field. These properties include film optical quality, mechanical strength properties (such as puncture resistance, tensile strength, impact strength, stiffness and tear resistance),, vapor transmission and gas permeability characteristics and performance in film converting and packaging equipment.
  • the expected service life of a perforating blade may be on the order of 2 to 4 weeks.
  • the service life of the perforating blade was reduced to a matter of hours. In such a case it may be necessary to close down an entire commercial line to change perforating blades at frequent intervals or the resulting product may become unsuitable due to poor quality perforations. Either situation provides a totally unacceptable commerical process.
  • low pressure-low density polyethylene film is tougher than the corresponding high pressure material, it was postulated that the cutting edges of the reduced- life perforating blade were wearing. However, in one instance, after a blade was no longer acceptable for perforating low pressure-low density polyethylene film, it was found that it was nevertheless still useful in perforating conventional high pressure-low density polyethylene for an additional period of time of about 3 weeks. It was also found that cutting edges coated on both sides with a hard material did not significantly extend the useful service life of a perforating blade in a process for making low pressure-low density polyethylene film bags.
  • U.S. Patent No. 4,064,776 discloses a method and apparatus for making tear-resistant, separable end-connected plastic film bags utilizing a perforating blade which is serrated in'shape and which is provided along its length with deep recesses beyond the cutting edge to define connecting tabs between the perforations across the width of the advancing film material. The blade is also heated to effect annealing of the perforation edges.
  • U.S . Patent No. 4,161,382 discloses an apparatus for making containers from thermoplastic sheet material, including a cutting blade having at least one cutting edge extending vertically at an oblique angle to the surfaces to be cut, wherein slots in the sheet are formed when the blade is moved vertically into the sheet material.
  • U.S. Patent No. 3,975,891 discloses a rotary mower blade made of outer layers of metal having an inner layer of extremely hard material and shaped such that attrition in use of the outer metal layers exposes the inner extremely hard material to maintain a sharp cutting edge. It is disclosed that a fine cutting edge is formed and maintained as a result of the wearing of the blade, instead of the blade becoming more dull by such wear.
  • U.S. Patent No. 3,618,654 discloses a blade for cutting plastic material such as tire stock, having a body of steel with a flat backing surface and a channel in one edge thereof which contains a ring of tungsten carbide to be ground flush with the steel body on one side and projecting outwardly so that it is exposed. on both sides and terminates in a cutting edge.
  • U.S. Patent No. 2,634,499 discloses a similar cutting edge, comprised of a piece of tungsten carbide bonded to a substrate and designed for cutting materials such as asphalt roofing and other abrasive compositions.
  • U.S. Patent No. 3,988,955 discloses a band saw blade comprising a steel body having a plurality of teeth spaced along one edge thereof. The tip of each tooth is coated with a hard carbide material and then impulse hardened. The coating overlaps both sides of the cutting edge.
  • the present invention comprises an improved process for cutting or perforating a plastic film sheet material employing a cutting or perforating blade which exhibits improved service life durability, the blade being composed of a metal substrate having a coating of a hard material on only one side thereof.
  • a process for making a continuous strip of interconnected and separable plastic film bags includes the steps-of providing, such as by tubular blown film extrusion, a tube of plastic film material and sealing and perforating the tube across its.width at spaced longitudinal intervals, wherein the perforating is accomplished with a blade coated on one side only with a hard material such as tungsten carbide.
  • the process is especially useful in the manufacture of continuous strips of interconnected but separable bags of low pressure-low density polyethylene film, employing a serrated metal perforating blade which is beveled or chamfered on one side only and whose flat side only is coated with a hard substance such as tungsten carbide.
  • these blades exhibit a significantly improved service life as compared to uncoated similar blades or similar blades coated on both sides.
  • the process of the present invention has particular utility in a process for cutting or perforating film sheets of low pressure-low density polyethylene, it is expected to be useful in cutting or perforating many different types of plastic materials, including conventional high pressure-low density polyethylene, high density polyethylene, polypropylene, polyvinyl chloride and the like.
  • the invention is expected to be useful in cutting or perforating paper or paper-like sheets.
  • low density polyethylene typically has a density of about 0.94 g/cc or lower while high density polyethylene has a density of above about 0.94 g/cc.
  • Conventional low density polyethylene has in the past been made commercially by the high pressure (i.e., at pressures of 15,000 psi and higher) homopolymerization of ethylene in stirred and elongated tubular reactors in the absence of solvents using free radical initiators.
  • a low pressure process for preparing low density polyethylene has been developed which has significant advantages as compared to the conventional high pressure process.
  • One such low-pressure process is disclosed in commonly-assigned, copending U.S. Applications Serial No. 12,720, filed February 16, 1979 and Serial No. 892,322, filed March 31, 1978 (a foreign-filed application corresponding thereto has been published as European Patent Publication No. 4647).
  • the above-identified copending application discloses a low pressure gas phase process for producing low density ethylene copolymers having a wide density range of about 0.91 to about 0.94 g/cc and a melt flow ratio of from about 22 to about 36 and which have a relatively low residual catalyst content and a relatively high bulk density.
  • the process comprises copolymerizing ethylene with one or more C 3 to C 8 alpha-olefins in the presence of a high activity magnesium-titanium complex catalyst prepared under specific activation conditions with an organo aluminum compound and impregnated in a porous inert carrier material.
  • the copolymers thus prepared are copolymers of predominantly (at least about 90 mole percent) ethylene and a minor portion (not more than 10 mole percent) of one or more C 3 to C 8 alpha olefins which should not contain any branching on any of their carbon atoms which is closer than the fourth carbon atom-
  • alpha-olefins are propylene, butene-1, hexene-1, 4-methyl pentene-1 and octene-1.
  • the catalyst may be prepared by first preparing a precursor composition from a titanium compound (e.g., TiCl Q ), a magnesium compound (e.g., MgCl 2 ) and an electron donor compound (e.g., tetrahydrofuran) by, for example, dissolving the titanium and magnesium compounds in the electron donor compound and isolating the precursor by crystallization.
  • a porous inert carrier such as silica
  • the resulting impregnated support may be activated by treatment with an activator compound (e.g., triethyl aluminum).
  • an activator compound e.g., triethyl aluminum
  • the polymerization process may be conducted by contacting the monomers, in the gas phase, such as in a fluidized bed, with the activated catalyst at a temperature of about 30 to 105°C and a low pressure of up to about 1000 psi (e.g., from about 150 to 350 psi).
  • the resulting low density ethylene copolymers may be formed into thin film having improved puncture resistance, high ultimate elongation, low thermal shrinkage and outstanding tensile impact strength, by extrusion through an extrusion die having a gap of greater than about 50 mils.
  • One such process is disclosed in commonly-assigned, copending U.S. Applications Serial No. 12,795, filed February 16, 1979 and Serial No.
  • the film thus prepared may contain conventional additives and may have a thickness of about 0.1 mil to about 20 mils and may be formed into a tube by the tubular blown film extrusion process.
  • low pressure-low density polyethylene ethylene polymers having a density of about 0.91 to about 0.94 such as the ethylene-C 3 to Ca alpha olefin copolymers described above.
  • plastic film bag-making machinery and processes are commercially known and available.
  • a typical process includes the steps of forming a plastic film tube by the tubular blown film extrusion process and advancing the plastic film tube in flattened form through a bag-making machine where the tube is heat-sealed across its width at spaced longitudinal intervals and perforated at similar intervals with a perforating knife to provide means for later separating the individual plastic film bags from the resulting continuous strip.
  • any known and commercially-available equipment can be employed. For example, to make garment-type bags which have a width of approximately 27 inches, Gloucester Engineering Company bag-making machines identified by Model Numbers 417 or 419 may be employed.
  • the operations are reversed; i.e. the large tube is first longitudinally slit-sealed followed by perforating and heat-sealing each of the resulting tubes.
  • Conventional means such as nip rolls driven at a speed greater than the tube advance speed in the machine, may be provided adjacent the exit of the bag-making machine to effect separation of the interconnected strips into individual bags.
  • the process of the present invention includes the step of perforating a plastic film with a perforating knife of improved durability.
  • the perforating operation is normally conducted by vertically stroking the perforating blad into and through the plastic film tube.
  • Figure 1 of the attached drawings schematically illustrates a vertical stroke heat-sealing and perforating apparatus of a commercially available bag-making machine. Referring to Figure 1, a tubular film 10 is shown advancing right to left in the drawing over supporting means 11. Conventional means (not shown) may be provided for momentarily stopping the advance of the plastic film tube, at which time the heat-sealing and perforating operations can occur.
  • sealing and perforating operations in commercial processes, may be repeated at a rate of from about 10 to 170 times per minute.
  • the cycle speed required of the perforating blade depends upon how rapidly the plastic film tube is advancing through.the bag-making machine. rhis, in turn, depends upon the size of the bags being made. It is apparent that for a given speed of advance, the rate of perforation is substantially less for long bags such as garment bags in comparison to produce bags where the perforations are much closer.
  • the plastic film tube may be advanced through the bag-making machine at a rate of about 10 to about 400 feet per minute or higher. Normally, the higher rates are for the longer bags such as garment bags.
  • the typical rate of advance in a process for producing produce-type bags having a length of about 16 to 20 inches is about 150 to about 160 feet per minute, at which speed and for 16 inch-long produce bags, a perforating blade cycle of about 147 times per minute would be expected.
  • the cycling time of the perforating blade may vary greatly depending upon how rapidly one wishes to advance the plastic film tube through the machine and upon the length of the bag being manufactured.
  • Those skilled in the art are well aware of the controlling factors.
  • the cycling speed of the perforating blade increases, the wearing of the blade becomes more rapid and hence this additional factor must be balanced in determining the desired or optimum operating conditions. Those skilled in the art may determine the various conditions of operation given the desired results.
  • the plastic film may not perforate cleanly, which is undesirable since uneven elongated film areas surrounding the perforation lines can lead to bag failure by premature tearing.
  • the severity of this problem is influenced by the film gauge with the thinner gauge films presenting more problems than thicker films.
  • the thickness of the plastic film bags may vary considerably depending upon the desired end use and particular plastic film employed. As an example, for low pressure-low density polyethylene, produce-type bags generally may have a film thickness of 0.0003 to 0.001 inch and garment-type bags may have a thickness of 0.0003 to 0.001 inch.
  • FIG. 2 A portion of a serrated perforating blade of the type which may be employed in the practice of the present invention is shown in Figure 2.
  • a serrated blade 16 is composed of a main body portion 17 and. a plurality of teeth 18 projecting outwardly therefrom along one edge thereof. Recesses or slots 19 are provided between adjacent teeth. Although the slots are shown as being rectangular in shape in Figure 2, they may take any form.
  • each tooth 18 is beveled such as by sharpening to provide chamfered faces 23 and 24 and cutting edges 20 and 21 (formed by the intersection of faces 23 and 24 and the flat side of each tooth 18).
  • Figure 3 illustrates a portion of the teeth area of an unslotted blade 25 which comprises a main body portion 26 provided along one edge thereof with a plurality of teeth 27.
  • Each tooth 27 may be sharpened to provide chamfered faces 28 and 29 and cutting edges 30 and 31 formed by the intersection of the chamfered faces and the flat side of each tooth.
  • Figure 4 illustrates, in exaggerated form, the tip area of each tooth of the blade of Figure 3.
  • the particular shape of the perforating blade employed in the practice of the present invention is not critical. It may be slotted or unslotted and the number of teeth or slots in the blade may vary depending upon the particular material being treated, the sizes of the bag and perforations, the speed at which the plastic film material is moving through the apparatus, etc. Those skilled in the art are aware of the various blade configurations that can be employed for these purposes. Generally, any conventional type and configuration of perforating blade can be used in the practice of the present invention. It is preferred, however, for perforating low pressure-low density polyethylene, that the blade be unslotted of the type illustrated in Figure 3. As stated above, many commercial bag-making machines are designed to accept one or more blades each ten inches in length. For unslotted blades of such length, best results for perforating low pressure-low density polyethylene have been obtained with blades having 40 teeth, although good results have also been obtained with blades having 27 or 50 teeth.
  • Slotted blades may also be employed in the present invention. Generally, any-slotted blade of conventional configuration may be employed, such as those represented by Figure 2. It is not necessary that each tooth be separated by a slot from each adjacent tooth which is the conventional configuration. The dimensions of the slotted blades may vary-depending on the nature of the material being perforated, the size of the bag being formed, the size of perforation desired, etc. As a general rule, when perforating low pressure-low density polyethylene, which is tough and tear-resistant, the width of each slot should not exceed about 0.030 inch.
  • the slot width may be on the order of 0.060 to 0.070 inch although when making garment bags of this material for example, slot widths up to about 0.125 inch may be tolerated.
  • the thickness thereof may be determined based on the strength of the metal constituting the blade, its expected level of use, the size of perforation required, etc.
  • a conventional perforating blade may be formed from a blank by machining and the teeth area is typically of a lesser thickness than the main body portion.
  • the thickness of the main body portion may be on the order of about 0.050 inch while the teeth may have a thickness on the order of about 0.010 to 0.015 inch.
  • the dimensions of a perforating blade are not particularly critical and all of the'foregoing dimensions may be varied depending on the circumstances.
  • a slotted and unslotted blade may depend on the degree of control desired or necessary in the bag-making machine.
  • perforations are obtained as a result of forcing the blade through the plastic film at least as far as into the slot whose width predetermines the distance between perforations.
  • the depth of the perforation stroke must be carefully controlled to provide the desired or necessary distance between perforations.
  • the materials of which the perforating blade may be made are not particularly critical.
  • An advantage of the present invention is that a relatively softer blade material may be employed since it is the hard metal coating which forms the cutting edge. In fact, as the cutting edges of the blade undergo wear, the softer blade material is worn away preferentially, thereby exposing the harder metal coating on one side of the blade. In effect, the blade becomes self-sharpening in use.
  • the blade substrate material is typically metal and any conventional cutting blade metal having a hardness of at least about 40 Rockwell may be employed, as is apparent to those skilled in the art.
  • An example of a suitable material is the carbon steel known as No. 1095. Spring steel is also expected to be useful.
  • the preferred material is No. 1095 carbon steel.
  • the coating which is on one side only of the perforating blade of the invention is a hard metal material.
  • this hard metallic coating should have a Rockwell hardness of at least about 50, preferably at least about 70.
  • hard metallic materials which are, or which are expected to be, suitable for use as the blade coating in the present invention include the metal carbides such as tungsten carbide; and nickel alloys, such as the nickel alloy commercially available from Electro-Coatings, Inc. under the tradename Ny-Carb (which comprises a nickel-phosphorus matrix containing about 30 weight % of silicon carbide particles- 1 to 3 microns in size- embedded therein).
  • Tungsten carbide is the preferred hard metallic coating material since it generally has a hardness of over 70 Rockwell.
  • tungsten carbide as used herein is meant to include both tungsten carbide per se as well as tungsten carbide containing small amounts of other hard metals such as cobalt.
  • tungsten carbide coatings are commercially available from Union Carbide Corporation which comprise cobalt in a mixture of tungsten carbides; for example, under the tradenames LW-30 (13 weight % Co - balance tungsten carbides); LW-lN30 (13 weight % Co - balance tungsten carbides); LW-1N40 (15 weight % Co - balance tungsten carbides); and LW-1N20 (11 weight % Co - balance tungsten carbides).
  • LW-30, LW-1N30 and LW-1N20 coatings have hardness values of 74-75, 72-73 and 71-72 Rockwell, respectively.
  • the LW-1N30 is preferred.
  • the hard metal coating may be formed on the perforating blade by any convenient method.
  • a preferred embodiment i.e., a chamfered, unslotted blade
  • the coating is formed on the flat side of the blade after sharpening as shown in Figures 5-7 of the drawings.
  • Figure 4 is a side view of one of the teeth of the blade of Figure 3, having a hard metal coating on its flat side.
  • a blade tooth 27 is shown which has a chamfered face 28 formed by edges 32 and 33 and cutting edge 30.
  • a coating 35 (shown in exaggerated form) is provided on the flat side of the tooth 27, thereby forming a new, hard cutting edge 36.
  • the hard metal .coating may be formed on the perforating blade by any suitable process.
  • a tungsten carbide coating may be formed by a commercially-available process of Union Carbide Corporation known as flame-plating. In this process, the coating material (tungsten carbide, with or without additives) is fired from a detonation gun at the part being coated at supersonic speeds and at very high temperatures. The process is more fully described in U.S. Patent No. 2,714,563, the disclosure of which is expressly incorporated herein by reference.
  • the coating particles strike the part being coated by this process with such high speed, it may be necessary, and it is therefore preferred, to support the perforating blade teeth from the side opposite the side being coated, in order to prevent deformation of the teeth.
  • the necessity for providing such support depends on the thickness and rigidity of the blade and the specific conditions of the flame plating operation.
  • the hard metal material may be coated onto the' blade substrate to a thickness of from about 0.0005 to 0.0015 inch, preferably from about 0.0005 to 0.0007 inch.
  • the tungsten carbide coating has a thickness on the order of about 0.0005 to 0.001 inch.
  • the present invention also contemplates other plastic film cutting operations, such as punching and slitting wherein the cutting instrument is coated on one side only with a hard metal coating of the types described above.
  • a circular blade is generally-used which may be formed of any conventional blade-type material, such as No. 1095 carbon steel.
  • Such blades are generally unslotted and are provided with teeth around the entire circumference of the blade. The teeth may be sharpened by beveling the inside edges thereof.
  • punching holes in plastic film material such as low pressure-low density polyethylene
  • the useful service life of such punching blades may be extended by coating the outside, flat surface thereof with a hard metal material such as tungston carbide in the same manner as discussed above.
  • slitting-type blades may be coated to extend their useful service life when slitting materials such as low pressure-low density polyethylene film.
  • Slitting blades are used in many different applications such as forming flat films from a film tube formed by a tubular blown film extrusion process. The tube may be slit on one or both sides to provide the flat film. In one instance, it was the practice to sharpen the slitting blades once a week when slitting conventional high pressure-low density polyethylene. When low pressure-low density polyethylene was employed in the process, it was found necessary to sharpen the slitting blades twice a day. These blades were curved and were sharpened on one edge only to provide a chamfered surface on that side.
  • New 10-inch long 40-tooth unslotted blades of No. 1095 carbon steel were sharpened to provide a chamfered face on one side of each tooth.
  • the flat side of the teeth of these blades was then coated with a LW-30 tungsten carbide to a thickness of 3 mils and a set of 5 blades was installed in a Gloucester Model 418 bag machine.
  • the machine was operated at a line speed of 170 feet per minute and a perforating speed of 122 cycles per minute to produce produce-type bags of low pressure-low density polyethylene having a thickness of 0.5 mil.
  • New 40-tooth unslotted perforating blades 10 inches long and composed of No. 1095 carbon steel and having a hardness of 46-48 Rockwell in the teeth area, were installed in a bag-making line using a Gloucester Engineering Model No. 418 bag-making machine.
  • the line was operated to make low pressure-low density polyethylene produce-type bags having a thickness of 0.5 mil.
  • the line speed was 170 feed per minute and the perforating cycle was 122 cycles per minute.
  • These blades became too dull to provide good perforations after only 24 hours of use.
  • the blades were removed from the machine and the tips of some of the teeth were observed to have rolled back thereby dulling those teeth.
  • a Ny-Carb coating (30 weight % of 1-3 micron particle; of silicon carbide embedded in a nickel-phosphorus matrix) was coated onto both sides of new 10-inch long, 40-tooth slotted perforating.blades formed of No. 1095 carbon steel and having slots 0.030 inch wide between each tooth, by a conventional plating process.
  • the Ny-Carb coating had a hardness of 60 -68 Rockwell and a thickness of 3 mils. These blades were then installed in the same type of Gloucester bag-making line as used in Example 1. The line was operated 3 t 253 feet per minute and at a perforating speed of 184 cycles per minute to produce the same type of low pressure-low density polyethylene produce-type bags as in Example 1 having a thickness of 0.5 mil. Right at the start of operation, it was noticed that the perforations were not of good quality and the blades after 21 hours became too dull and were removed.
  • a second set of the same type of perforating blades was coated on both sides with the same Ny-Carb coating by the same plating technique to a thickness of 3 mils, and a hardness of 60-68 Rockwell and placed in the same bag-making line and then used to make the same type of low pressure-low density polyethylene bags.
  • This set of blades lasted only 20 hours before becoming dull enough to warrant removal from the machine.
  • Two sets of new 10-inch long, 50 -tooth perforating blades formed of No. 1095 carbon steel were spray-coated on both sides with a conventional aerosol-type Teflon spray and left to dry for six hours.
  • the blades were coated again on both sides with the same Teflon spray and left to dry overnight.
  • the thickness of the Teflon coating was 0.5 mil.
  • One set of blades was installed in a bag-making line using a Gloucester Model No. 418 machine which was then operated at a line speed of 170 feet per minute and at a perforating speed of 122 cycles per minute to make low pressure-low density polyethylene bags having a thickness of 0.5 mil.
  • the blades were removed after 26 hours when the perforations became poor.
  • the second set of teflon-coated blades, coated in the same manner lasted an additional 4 hours in the same line when operated under substantially the same conditions.
  • a set of new, 10-inch long 50-tooth slotted (each slot being 0.035-0.040 inch wide) perforating blades formed of No. 1095 carbon steel were dip-coated with Teflon 8-403 to a thickness of 0.2-0.3 mil followed by baking.
  • the resulting blades were installed in a bag-making line using a Gloucester Model No. 418 machine and the line was operated at a speed of 170 feet per minute and a perforating speed of 122 cycles per minute to produce low pressure-low density polyethylene bags.
  • the blades were removed after about 4 days due to poor perforations.
  • the set of blades of Example 2 were ' resharpened after removal and re-installed in the bag-making line which was again operated under substantially the same conditions as in- Example 2.
  • the resharpened blades failed to give good perforations after only 8 to 24 hours.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Forests & Forestry (AREA)
  • Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
  • Making Paper Articles (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Materials For Medical Uses (AREA)
  • Nonmetal Cutting Devices (AREA)
  • Auxiliary Devices For And Details Of Packaging Control (AREA)
EP81104658A 1980-06-19 1981-06-16 Verfahren zum Schneiden und Perforieren von Kunststoff-Folie Withdrawn EP0042586A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US16093980A 1980-06-19 1980-06-19
US160939 1980-06-19

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EP0042586A1 true EP0042586A1 (de) 1981-12-30

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Application Number Title Priority Date Filing Date
EP81104658A Withdrawn EP0042586A1 (de) 1980-06-19 1981-06-16 Verfahren zum Schneiden und Perforieren von Kunststoff-Folie

Country Status (9)

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EP (1) EP0042586A1 (de)
JP (1) JPS5727742A (de)
KR (1) KR830006085A (de)
AU (1) AU7122881A (de)
BR (1) BR8103774A (de)
CA (1) CA1177383A (de)
FI (1) FI811863L (de)
NO (1) NO812033L (de)
ZA (1) ZA813869B (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0628379A1 (de) * 1993-06-11 1994-12-14 Helmut Schäfer Verfahren zur Herstellung von selbstschärfenden Messerschneiden sowie selbstschärfende Messerschneide
EP0691862A1 (de) * 1994-02-02 1996-01-17 Allegiance Corporation Schlitzventil für gaszerstäuberjet
EP0707921A3 (de) * 1994-10-22 1997-07-23 Zwilling J A Henckels Aktienge Messer und Verfahren zur Herstellung eines Messers
EP0850731A2 (de) * 1996-11-07 1998-07-01 KOENIG & BAUER-ALBERT Aktiengesellschaft Schneidmesser für einen Falzapparat einer Rollenrotationsdruckmaschine
WO2003082533A1 (en) * 2002-03-28 2003-10-09 Hardide Limited Self-sharpening cutting tool with hard coating
EP1378328A2 (de) * 2002-07-01 2004-01-07 Premark FEG L.L.C. Kreisförmiges Verbundmesser für Aufschnittschneider
FR2841819A1 (fr) * 2002-07-02 2004-01-09 Henri Georges Adolphe Dussud Machine a fabriquer les sacs plastiques a partir d'une gaine
EP1985726A1 (de) * 2007-04-27 2008-10-29 WMF Aktiengesellschaft Schneidwerkzeug mit einer Hartstoff verstärkten Schneidkante
US7726103B2 (en) 2006-11-17 2010-06-01 Liqui-Box Canada Inc. Resilient backing member for the use with an impulse heating element
AT515706A1 (de) * 2014-10-24 2015-11-15 Rieder Rudolf Schneidesystem mit Schnellhalter
CN108638580A (zh) * 2018-08-01 2018-10-12 广东顺德博丰塑料机械有限公司 一种制袋机
EP4173978A1 (de) * 2021-10-27 2023-05-03 Tchibo GmbH Verfahren und vorrichtung zur herstellung einer portionenkapsel

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58177224U (ja) * 1982-05-18 1983-11-26 三菱マテリアル株式会社 ろう付け式超硬シヤ−ブレ−ド
JPH0628917B2 (ja) * 1984-01-30 1994-04-20 旭化成工業株式会社 合成樹脂フイルムの袋状物の製造方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2107043B2 (de) * 1971-02-15 1973-02-01 Vorrichtung zum querschweissen von intermittierend bewegten folienbahnen aus thermoplastischem kunststoff
US3975891A (en) * 1974-02-22 1976-08-24 Roland Eric Gunther Mower blades
DE2533471A1 (de) * 1975-07-25 1977-02-10 Greiner Gmbh & Co Wendeschneidplatte
US4019947A (en) * 1975-09-10 1977-04-26 Fmc Corporation Multipurpose sealing and severing method and mechanism
US4064776A (en) * 1974-11-26 1977-12-27 Union Carbide Corporation Apparatus for making tear resistant separable end-connected bags

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2107043B2 (de) * 1971-02-15 1973-02-01 Vorrichtung zum querschweissen von intermittierend bewegten folienbahnen aus thermoplastischem kunststoff
US3975891A (en) * 1974-02-22 1976-08-24 Roland Eric Gunther Mower blades
US4064776A (en) * 1974-11-26 1977-12-27 Union Carbide Corporation Apparatus for making tear resistant separable end-connected bags
DE2533471A1 (de) * 1975-07-25 1977-02-10 Greiner Gmbh & Co Wendeschneidplatte
US4019947A (en) * 1975-09-10 1977-04-26 Fmc Corporation Multipurpose sealing and severing method and mechanism

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0628379A1 (de) * 1993-06-11 1994-12-14 Helmut Schäfer Verfahren zur Herstellung von selbstschärfenden Messerschneiden sowie selbstschärfende Messerschneide
EP0691862A1 (de) * 1994-02-02 1996-01-17 Allegiance Corporation Schlitzventil für gaszerstäuberjet
EP0691862A4 (de) * 1994-02-02 1996-10-30 Baxter Int Schlitzventil für gaszerstäuberjet
EP0707921A3 (de) * 1994-10-22 1997-07-23 Zwilling J A Henckels Aktienge Messer und Verfahren zur Herstellung eines Messers
EP0850731A2 (de) * 1996-11-07 1998-07-01 KOENIG & BAUER-ALBERT Aktiengesellschaft Schneidmesser für einen Falzapparat einer Rollenrotationsdruckmaschine
EP0850731A3 (de) * 1996-11-07 1998-09-30 KOENIG & BAUER-ALBERT Aktiengesellschaft Schneidmesser für einen Falzapparat einer Rollenrotationsdruckmaschine
US7166371B2 (en) 2002-03-28 2007-01-23 Hardide Limited Self-sharpening cutting tool with hard coating
WO2003082533A1 (en) * 2002-03-28 2003-10-09 Hardide Limited Self-sharpening cutting tool with hard coating
AU2003214433B2 (en) * 2002-03-28 2008-08-07 Hardide Coatings Limited Self-sharpening cutting tool with hard coating
CN100366404C (zh) * 2002-07-01 2008-02-06 浦玛玛柯Feg有限责任公司 复合圆形切片机刀片和制造方法
EP1378328A3 (de) * 2002-07-01 2005-01-26 Premark FEG L.L.C. Kreisförmiges Verbundmesser für Aufschnittschneider
US7194933B2 (en) 2002-07-01 2007-03-27 Premark Feg L.L.C. Composite circular slicer knife
US7257899B2 (en) 2002-07-01 2007-08-21 Premark Feg L.L.C. Composite circular slicer knife
EP1378328A2 (de) * 2002-07-01 2004-01-07 Premark FEG L.L.C. Kreisförmiges Verbundmesser für Aufschnittschneider
FR2841819A1 (fr) * 2002-07-02 2004-01-09 Henri Georges Adolphe Dussud Machine a fabriquer les sacs plastiques a partir d'une gaine
US7726103B2 (en) 2006-11-17 2010-06-01 Liqui-Box Canada Inc. Resilient backing member for the use with an impulse heating element
EP1985726A1 (de) * 2007-04-27 2008-10-29 WMF Aktiengesellschaft Schneidwerkzeug mit einer Hartstoff verstärkten Schneidkante
AT515706A1 (de) * 2014-10-24 2015-11-15 Rieder Rudolf Schneidesystem mit Schnellhalter
CN108638580A (zh) * 2018-08-01 2018-10-12 广东顺德博丰塑料机械有限公司 一种制袋机
EP4173978A1 (de) * 2021-10-27 2023-05-03 Tchibo GmbH Verfahren und vorrichtung zur herstellung einer portionenkapsel
WO2023072773A1 (de) * 2021-10-27 2023-05-04 Tchibo Gmbh Verfahren und vorrichtung zur herstellung einer portionenkapsel

Also Published As

Publication number Publication date
ZA813869B (en) 1982-06-30
KR830006085A (ko) 1983-09-17
JPS5727742A (en) 1982-02-15
NO812033L (no) 1981-12-21
FI811863L (fi) 1981-12-20
CA1177383A (en) 1984-11-06
BR8103774A (pt) 1982-03-09
AU7122881A (en) 1981-12-24

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