Method of compressing and heat sealing the interior of the junction of a liquid container closure

Abstract

A method of compressing and heat sealing the interior of a joint of a liquid container closure, the joint having an edge of a 180° folded polycoated paperboard panel between the area of the edge of the polycoated film element and the polycoated paperboard panel, wherein the edge of the 180° folded polycoated paperboard panel and the interior of the polycoated paperboard panel overlap the edge of the polycoated film element. The joint of the folded, compressed and pre-sealed liquid container closure is compressed and heat sealed from the outside of the container by a punch having a hard spherical front head, the hard spherical front head being flexible, and the hard spherical front head moving laterally after the embossing of the polycoated paperboard panel on the outside of the container during the compression and sealing of the edge of the 180° folded polycoated paperboard panel.

Description

Technical Field

[0001] The present invention provides a method for compressing and heat-sealing the interior of a liquid container closure "joint" to make it impermeable to liquid, the closure joint comprising an edge of a polymer-coated cardboard sheet folded at 180° between an edge region of a polymer-coated cardboard sheet and an edge region of a polymer-coated membrane element. Background Technology

[0002] In mass production, during long production cycles with a large number of machine strokes, the compression tool is typically kept in exactly the same precise position. A 1mm tolerance is required to push the polymer-coated cardboard sleeve onto the inner anvil without folding one or more polymer-coated cardboard walls. Therefore, the polymer-coated cardboard sleeve must have a cross-section 2mm larger than the inner anvil. Because of this tolerance between the rectangular polymer-coated cardboard sleeve and the rectangular anvil, the container closure edges of all 180º folded polymer-coated cardboard panels will be offset during mass production and will not be in the same position during compression and heat sealing. This can damage the edges of the 180º folded polymer-coated cardboard panels or create channels, allowing liquid to seep into the container and causing leakage and damage to surrounding products during storage and distribution.

[0003] This invention is applicable to the design of closures for various polymer-coated cardboard containers with medium or heavy cardboard area weight, wherein the back portion of the container closure at the edge of the 180º folded polymer-coated cardboard sheet is compressed and heat-sealed between the polymer-coated cardboard sheet and the edge of the polymer film element to make it impermeable to liquid.

[0004] When using ultrasound for heat sealing, an internally heated alloy anvil with an etched surface pattern of 0.0045MT-11050 texture and a weld horn with knurled pentahedral / square pyramidal micropatterns in different heat-sealing areas are required. This allows for control of the energy direction of the container closure to be heat-sealed in specific weld areas, enabling perfect subsequent opening of the closure. Additionally, one of the etched surface portions, with a semi-hexagonal texture protruding 0.013 to 0.030 inches from the anvil surface, may have a unilateral serrated edge. Multiple pentahedral points need to be machined into a flat forehead, typically to prevent multiple sharp points from cutting through the polymer layer. The angle between the pentahedral plates can be 60º. Incorporating a spring-loaded compression tool into the ultrasonic horn introduces several additional technical problems; the activated ultrasonic horn vibrates at high frequencies, which can cause any moving elements incorporated into the ultrasonic horn to interfere with the frequency and destabilize the ultrasonic welding process.

[0005] According to the invention, the rigid ball-shaped front head of the compression and heat-sealing punch overlaps the pre-sealed container joint with the rigid ball-shaped front head of the compression and heat-sealing punch embedded in the flexible elastomer body from the outer wall side of the polymer-coated cardboard sheet, thereby laterally bending to seal the 180º pre-folded edge of the polymer-coated cardboard between the outer side of the inner sheet of the polymer-coated cardboard and the edge region of the polymer-coated film element abutting the heated anvil, without compromising the liquid resistance of the 180º folded edge of the polymer-coated cardboard. Vibration of the ball-shaped front head of the compression punch may be necessary.

[0006] The anvil needs to be coated with a non-adhesive polytetrafluoroethylene (PTFE) coating to prevent polyethylene (PE) from adhering to the heated alloy mandrel during the heat-sealing compression process. When multiple stacked polymer-coated cardboard sheets are compressed and heat-sealed using ultrasonic technology, all layers are sealed together. To prevent some areas from sealing together later, a non-heat-sealing water-based overprint varnish is applied to these surface areas during flexible plate printing to prevent them from being opened later.

[0007] After heat sealing, when the container closure is opened, some areas of the membrane element need to be peeled off from the polyethylene-coated cardboard. Therefore, a peelable composite layer must be applied to the surface of the membrane element. Peelable lacquer or polymer composite coatings that simultaneously provide sufficient heat-sealing strength can be complex applications. To circumvent this problem, according to the present invention, one side of the non-peelable low-density polyethylene (LDPE) coating of the polyester (PE) film is permanently heat-sealed to the non-peelable low-density polyethylene (LDPE) cardboard coating, and the other side of the polyester (PE) film is coated with a peelable LDPE composite layer. A portion of the film is folded to form a lip along the perforation line, and the two peelable LDPE composite layers of the lip are heat-sealed together, allowing for delamination if the lip is torn along the perforation line, and retaining the non-peelable LDPE layer attached to the cardboard after the box-like closure is opened.

[0008] By installing a semi-deep cutting die aligned with the printing press used to produce the container blank in a rotary crease and cut production tool, the deeply polymer-coated cardboard portion can be delaminated and removed via vacuum before being folded 180º in the filling machine. The recessed portion at the edge of the 180º folded polymer-coated cardboard minimizes the radius of the folded edge of the polymer-coated cardboard that is heat-sealed with the polymer-coated film element, thereby eliminating any liquid path. Summary of the Invention

[0009] Therefore, the object of the present invention is to eliminate the defects and disadvantages associated with the sealing methods known in the prior art as pointed out above.

[0010] Another object of the present invention is to provide a more economical container.

[0011] Another objective of this invention is to eliminate the plastic screw caps required by consumers for all prior art liquid container containers and, in addition, to introduce a cardboard biopolymer coating to provide a 100% biodegradable container, thereby protecting the environment in a more effective way.

[0012] Another object of the present invention is to provide a container that will reduce the consumption of natural resources. Attached Figure Description

[0013] Figure 1 It is an enlarged cross-sectional view of the compression and heat-sealing station, in which a 180º folded polyethylene-coated cardboard sheet is stacked inside an outer polyethylene (PE)-coated cardboard and an inner membrane element 2, wherein a compression and heat-sealing punch with a rigid front head formed by flexible spheres will bypass the edge of the 180º folded polyethylene (PE)-coated cardboard sheet to make an inclined and guided emboss in the pre-folded and compressed closure.

[0014] Figure 2 It is based on Figure 1 An enlarged side cross-sectional view of the edge of a 180º folded polyethylene-coated cardboard board, after compression and heat sealing, wherein the edge of the 180º folded polyethylene-coated cardboard board is sealed to be impermeable to liquid between the interior of the outer polyethylene-coated cardboard board and the inner polyethylene-coated membrane element.

[0015] Figure 3 It is a plan view of the internal cross-section of the container closure, showing the internal leak-proof joint, in which the edge of the polyethylene-coated membrane element overlaps with the inner edge of the 180º polyethylene-coated cardboard board and the interior of the outer polyethylene-coated cardboard board.

[0016] Figure 4 It is an enlarged isometric view of the recessed portion of the edge of a 180º folded polyethylene-coated cardboard board.

[0017] Figure 5 This is an enlarged side cross-sectional view of a polyethylene (PE) coated cardboard board that is heat-sealed to the membrane lip.

[0018] Figure 6 This is an enlarged side cross-sectional view of a polyethylene (PE) coated cardboard sheet that is heat-sealed to a portion of the membrane lip in a non-peelable manner, wherein the other side of the membrane lip can be peeled off from the membrane element, thereby delaminating and breaking along the perforation line of the membrane element when the closure is opened.

[0019] Figure 7 This is a plan view of an ultrasonic heat-sealing knurled pattern with oblique and vertically oriented sealing portions having interrupted middle sections. The plan view shows the cross-sectional pattern of the seal of a cardboard container closure when it is folded flat.

[0020] Figure 8 It is a top view of a polymer-coated cardboard first board having closure opening protrusions connected by two different perforated line patterns, wherein the two perforated protrusions are heat-sealed to a second polymer-coated cardboard board.

[0021] Figure 9 This is an isometric view of a mandrel assembly having a textured etched mandrel surface and a mandrel head having two raised semi-hexagonal surface portions. The mandrel head is connected to the mandrel base by four hollow pins to prevent heat transfer from the heated top plate to the mandrel base.

[0022] Figure 10 This is a side view of a four-spindle indexing rotor, where the first spindle on the left has a rectangular container sleeve that is pushed onto the spindle by an indexing timing belt. A closure is folded between the first and second spindle stations. An ultrasonically welded stack in the upper second spindle station heat-seals the closure. According to the invention, the third spindle station on the right compresses and seals the closure to be impermeable to liquids. In the lower fourth spindle station, a rectangular cardboard structure including the completed folded and sealed closure is removed from the spindle. As the spindle plate passes beneath an induction coil between the fourth and first spindle stations, the induction coil heats the top plate of the spindle. Detailed Implementation

[0023] according to Figure 1The channel 8 along the edge 7 of the 180º folded polymer-coated cardboard sheet is formed in a previous heat-sealing station. By pressing the front head 6 of the rigid ball of the compression and heat-sealing punch against the heated mandrel 1 to compress and heat-seal the joint of the container closure into a liquid-impermeable state, during the compression and sealing of the edge 7 of the 180º folded polymer-coated cardboard sheet between the inner sheet 3 of the outer polymer-coated cardboard sheet and the edge region 2 of the polymer-coated film element, the front head 6 of the rigid ball of the compression and heat-sealing punch can move laterally within the flexible elastomer body 5, thereby compressing and heat-sealing the channel 8 into a liquid-impermeable state without damaging the polyethylene coating of the edge 7 of the 180º folded polyethylene-coated cardboard sheet. Reference numeral 6 shows a gas or liquid passage in the rigid punch that cools the attached / adjacent flexible elastomer element of the compression and heat-sealing punch during extended production cycles.

[0024] according to Figure 2 The diagram shows the liquid-impermeable joint 9 after being compressed and heat-sealed into a liquid-impermeable state according to the present invention.

[0025] according to Figure 3 , showing according to Figure 2 The accompanying figure is a top cross-sectional view, in which polymer-coated membrane elements 10 are overlapped and heat-sealed to a 180° folded polymer-coated cardboard sheet, the 180° folded polymer-coated cardboard sheet including a free edge 11 with a leak-proof joint 12, the leak-proof joint 12 being heat-sealed into a liquid-impermeable front end formed by a sphere within a circle 13. Reference numeral 14 indicates a potential liquid path that is sealed into a liquid-impermeable state within the circle 13 by the sphere-formed front end after compression and heat sealing.

[0026] according to Figure 4 The image shows a recessed edge portion 16 at the edge of a 180º folded polymer-coated cardboard board, which reduces and eliminates liquid path inlets 15.

[0027] according to Figure 5 The illustration shows a polymer-coated cardboard sheet having a membrane lip 17 with perforated lines along the fold line, wherein the non-peelable side of the outer lip of the membrane element is permanently heat-sealed to the polymer-coated cardboard sheet.

[0028] according to Figure 6 The illustration shows a polymer-coated cardboard sheet permanently heat-sealed to a film lip, wherein the polymer-coated cardboard sheet including the film lip is delaminated from the film in region 18 by tearing the film lip along perforation line 19.

[0029] according to Figure 7 The image shows a vertically oriented knurled seal pattern 20 and an obliquely oriented knurled seal pattern 21 attached to a flared recessed plate 22.

[0030] according to Figure 8 The diagram shows polymer-coated cardboard protrusions 25 and 26 connected by perforated lines at the edges of a polymer-coated cardboard panel 23. Furthermore, the polymer-coated cardboard protrusions 25 and 26 are heat-sealed to the polymer-coated cardboard panel 23. In the case where the first perforation begins cutting at the edge of the cardboard, the length of protrusion 26 joined to the perforated line is typically greater than half the total length across the protrusion, and the entire protrusion 25 will be torn open when lifted by the unsealed cardboard panel 23. In the case where the first perforation does not begin cutting at the edge of the cardboard, the length of protrusion 26 joined to the perforated line is typically less than half the total length across the protrusion, thus allowing delamination along the perforated line. The layers of one cardboard protrusion 26 remain connected to the polymer-coated cardboard panel 23, and the layers of the other cardboard protrusion 25 remain connected to the polymer-coated cardboard panel 24. Panel 26 can be torn open, thus providing contactless opening of the closure.

[0031] according to Figure 9 Four hollow alloy pins 28 are shown to prevent heat transfer from the heated (200°C) mandrel top plate 27 to the mandrel base 29. When the temperature of the mandrel top plate 29 drops to a predetermined level, a wireless infrared sensor sends a signal to a temperature controller, which activates an induction coil. As the mandrel top plate 29 passes under the induction coil, the ferromagnetic material in the mandrel top plate 27 is activated by heating, thus maintaining the mandrel top plate 27 at a constant temperature of 200°C ± 10°C. Alternatively, a hot air blower or infrared heating element is used to turn the mandrel top plate 27 on and off. A third alternative is a 100-watt to 150-watt heating element incorporated into the mandrel top plate 27, controlled by a wireless infrared sensor with an image recognition camera that reads an individual image of each mandrel, identifies the temperature of the corresponding mandrel top plate, and sends a signal to the temperature controller of the mandrel top plate. Each of the four passages has four rotating mandrels connected to the indexing shaft. Eighteen power supply lines are connected to sixteen heating elements in the top plate 27 of the mandrel and are connected by the following: hollow pins 28, mandrel base 29 and a spindle with nine channel slip rings connected to each end of the mandrel indexing shaft.

[0032] according to Figure 10The diagram shows a side view of a four-spindle indexing rotor. The first spindle 30 has a rectangular container sleeve that is pushed onto the spindle by a polymer paddle 31 reinforced with a front of indexing stainless steel. The paddle 31 is welded to an annular steel-reinforced polyurethane (PUR) timing belt 32. By rotating a bevel gearbox 33, the closure is folded between the left-oriented first spindle 30 and the upward-oriented second spindle 41. The bevel gearbox 33 has two folding arms 34 of different lengths located on either side of the closure. As the gearbox rotates about a fixed central axis 35, the folding arms 34 rotate in opposite directions and pre-fold the closure. Two guides 36 have different profile levels, thereby folding the closure plane before entering beneath an ultrasonically welded horn-shaped member 37. The top-oriented mandrel station seals the box-shaped closure via an ultrasonic stack comprising a horn-shaped element 37, an intensifier 38, and a transducer 39, driven by a pneumatic actuator 40 oriented at the central top of the ultrasonic stack. The right-oriented third mandrel station 42 includes an additional magnified compression mold with a detailed view, which, according to the invention, compresses and heat-seals the joint of the ultrasonically pre-sealed closure into a liquid-impermeable state. In the downward-oriented fourth mandrel station 43, a vacuum chuck initially pulls the outer plate of the container a very small distance, releasing the closure inside the container from the front head of the mandrel, and two arms further push the rectangular box-shaped structure with the folded closure from the mandrel into the downward-oriented cavity strip. Between the lower third mandrel station 43 and the left-oriented first mandrel station 30, an induction coil 44 embedded in the Telfon (PEFE) body is activated, thereby maintaining the top plate of the mandrel at a constant temperature.

[0033] This invention should not be considered as limited to the specific examples described above, but should be understood to encompass all equivalent methods and processes in all aspects, as well as a variety of materials and structures to which this invention may be applied, as will be very apparent to those skilled in the art upon studying the present specification.

Claims

1. A method for compressing and heat-sealing the interior of a joint of a liquid container closure, said joint having an edge of a polymer-coated cardboard sheet folded 180º between a region of an edge of a polymer-coated cardboard sheet and an edge of a polymer-coated membrane element, wherein, The edges of the 180º folded polymer-coated cardboard sheet and the interior of the polymer-coated cardboard sheet overlap with the edges of the polymer-coated membrane element, characterized in that the joint of the folded, compressed, and pre-sealed liquid container closure is compressed and heat-sealed from the outside of the container by a punch having a rigid spherical front head embedded in a flexible elastomer body for compression and heat sealing, the rigid spherical front head being flexible, and the rigid spherical front head moving laterally after imprinting the polymer-coated cardboard sheet outside the container during the compression and sealing of the edges of the 180º folded polymer-coated cardboard sheet; the rigid spherical front head heat-seales the edges of the 180º folded polymer-coated cardboard sheet between the interior of the polymer-coated cardboard sheet outside the container and the edges of the polymer-coated membrane element into a liquid-impermeable state without damaging the polymer coating on the edges of the 180º folded polymer-coated cardboard sheet.

2. The method for the interior of the joint of the compression and heat-sealing liquid container closure according to claim 1, characterized in that, The perforation line of the membrane element was damaged when the liquid container closure was opened.

3. The method for the interior of the joint of a compression and heat-sealing liquid container closure according to claim 1 or 2, characterized in that, Polymer-coated cardboard protrusions are heat-sealed to polymer-coated cardboard sheets. When the length of the cardboard protrusions combined with the perforation line is greater than half the total length spanning the entire cardboard protrusion, the cardboard protrusions are torn when lifted by the unsealed cardboard sheet. When the length of the cardboard protrusions combined with the perforation line is less than half the total length spanning the entire cardboard protrusion, delamination occurs along the perforation line. One layer of the cardboard protrusion remains connected to the polymer-coated cardboard sheet, and the other layer of the cardboard protrusion remains connected to the polymer-coated cardboard sheet. During this delamination, the cardboard sheet can be torn apart, thereby providing contactless opening of the liquid container closure.

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