Package making – Methods – Forming a cover adjunct or application of a cover adjunct to...
Reexamination Certificate
1998-06-08
2004-04-20
Sipos, John (Department: 3721)
Package making
Methods
Forming a cover adjunct or application of a cover adjunct to...
C053S412000, C053S133100, C053S133200, C156S069000, C156S309900, C156S321000, C156S322000, C493S087000
Reexamination Certificate
active
06722102
ABSTRACT:
BACKGROUND ART
It is known from U.S. Pat. No. 3,498,868 to bond a flange of a plastics pouring spout to a two-ply thin gauge plastics film of a bag. An annular area of an axially inner surface of a flange of the spout is so selected for heating that the non-heated areas surrounding or close to the heated area are sufficient to prevent distortion of the shape of the flange, thus maintaining the flange in the shape in which it has been moulded. At this heated area is a sufficient mass of plastics material that a heat reservoir is created which maintains some of the initially supplied heat while the fitment is being moved from a flange-heating station to a joining station where the plastics film is to be applied. The heat carried is sufficient that merely a sufficiently light pressure to only maintain contact between the engaged film and the heated area will be adequate to achieve a joining between the two. At the flange-heating station the spout is lifted by a plunger into contact with an electrical, annular, heating element, to apply the element to the area to be heated; the surface temperature of the element is above the fusion temperature of the plastics of the flange so as quickly to heat this annular area above its melting point [for example may be approximately 193° C. (380° F.) with polyethylene (PE)] and yet, it is stated, the flange is so supported by the non-heated areas of the flange and the plunger surface that the spout remains undistorted. The contact of the element with the flange is of a short duration consistent with lack of distortion of the plastics material of the flange. In some cases, it may be necessary to apply heat to the plastics material from both sides. At the joining station, the spout is raised by another plunger through an opening in the film and an annular pressing element is brought into light contact with the film to urge it against the flange. If the flange and the two-ply film thicknesses are such that the flange does not have enough heat at engagement to completely activate the thin film, a minimum amount of heat would be added to the film, as for example 127° C. (260° F.) for PE by providing electrical heating of the pressing element. The heat provided by the latter electrical heating is equal to or less than the heat applied to the flange at the flange-heating station and the pressure is very light. The heat will be only sufficient to cause the plastics film to become fluid or mobile, sufficient heat having been retained in the heated part of the flange so that, over a short dwell time, molecular diffusion will take place on the interface and thereby provide a weld or joining of the parts one to the other. Although the temperature applied to the flange may be well above the melting point of the flange, the subsequent heat at the point of joining of the thin plastic film and the flange will be only sufficient to have an interfacial temperature in the fluid region of the plastics. Under some conditions, where an extremely thin plastics film is to be joined, sufficient heat may be available from the thick flange to achieve fluidity in the film without the application of heat at the joining station.
U.S. Pat. No. 3,231,444 discloses a method of heat-sealing a thermoplastic pour spout fitment to the exterior surface of one of two adjacent sheets of thermoplastic material to form a bag. A length of thermoplastic bag tubing is heat-sealed at both ends. The fitment and the tubing are of compatible materials. Radiant heat, for example from an infra-red heater bar, is directed at the bottom surface of the fitment, which surface is formed with an annular rib, or a plurality of concentric annular ribs. Heat can also be provided by a hot plate in contact with the rib(s). The heat is applied for a length of time sufficient to reduce the rib(s) to a softened or molten state, appropriate for heat sealing. The fitment is then pressed against the outer surface of an upper wall of the bag, for example by means of an appropriately shaped anvil. To reduce the possibility of adherence at the interface of the two walls of the bag, a water-cooled chamber is placed in contact with the outer surface of the lower wall so as to conduct heat away from the interface. The or each rib, which is continuous so as to provide a liquid-tight seal between the bag and the fitment, is thereby fused to the outer surface of the upper wall of the bag. Immediately prior to filling the bag, the bag wall at the opening of the fitment is punctured to permit filling of the bag through the fitment and then the fitment is closed by a cap. The fitment surface against which the heat is directed is of a large area relative to the cross-sectional area of the rib(s), so that only the rib(s) is/are reduced to a softened or molten state.
Hereto, pour spout fitments have been secured to thermoplastic-coated container panels by various methods.
In U.S. Pat. No. 4,813,578, the following method is employed: A mandrel is inserted into the interior of the still-open mouth of the container, with the mandrel abutting the interior surface of a barrier layer and forming a back-up support. Hot air or radiant heat is applied to the external surface of a gable top wall immediately around an opening to thereby soften the polyethylene coating, with a pour spout fitment flange placed on the softened layer to thereby adhere the flange to the wall. An external mandrel is also employed to press the assembly against the internally positioned mandrel. This pressure is maintained until the coating cools and thereby effects permanent adhesion of the flange to the wall. U.S. Pat. No. 4,813,578 discloses that other methods, such as ultrasonic adhesion and impulse heating, may be employed.
U.S. Pat. No. 5,249,695 merely recites that attachment to the polymer-coated paperboard panel is accomplished by welding or otherwise adhering a spout fitment flange to the polymer coating.
U.S. Pat. No.5,110,041 discloses that dual lanes of pour spout fitment sealing apparatus are integrated in line with conventional form/fill/seal production lines. Pre-sided carton blanks are opened to tube configurations and placed in flight pockets on an indexing conveyor for step-wise advance to each fitment sealing apparatus. At the sealing apparatus, the fitments are gravity-fed down a track and released one-by-one by an escapement to a pair of fitment retaining clamps positioned in front of the spout hole of each carton blank advanced to the sealing apparatus. A timing control causes the clamps to move apart at the same time as an ultrasonic sealing horn advances to press the fitment into contact with the outside thermoplastics layer of the blank and an anvil is inserted into the blank. The horn is energized to seal the fitment to the blank, the horn and the anvil are retracted, and the clamps are moved back to receive the next fitment. In an alternative embodiment, the fitment is sealed to the outside layer by hot-metal adhesive which is applied to the sealing surface of the fitment just prior to pressing the fitment against the outside layer. Heat may be applied to tackify the adhesive by a hot anvil or sealing head equipped with heating elements.
U.S. Pat. No. 4,964,562 and U.S. Pat. No. 5,152,438 each utilize an ultrasonic sealing horn and a back-up support mandrel operative around respective pouring apertures.
U.S. Pat. No. 4,948,015 discloses the use of an ultrasonic horn to bond a flange of a pour spout fitment to an inner or back surface of a container panel around a pouring aperture.
U.S. Pat. No. 4,669,640 suggests fusing a pour spout flange to an inside surface of a carton gable top either thermally or ultrasonically.
U.S. Pat. No. 5,088,643 states that a pour spout fitment is preferably adhered to the outer surface of a container panel by impulse heating under pressure such as ultrasonic sealing although other methods may be used as desired.
DE-A-3838739 discloses a method in which a thermoplastic disc is applied to the outside thermoplastic layer of the laminate of the container so that the middle of the disc is sealed to
Pape Leslie
Rochelle Robert Edwin
Elopak AG
Huynh Louis
Sipos John
LandOfFree
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