DE1952557A1 - Packaging method and device - Google Patents

Description

WR Grace ₀ ft Co. (British 50434/68 - prio 23.lO.i968 Mew York. NY, V.St.A. ^A / ¹⁴ * ²⁰ - ⁶ ^) Hamburg, October 15th, 1969 Packaging method and device

The invention relates to shrinkage and welding of thermoplastic packaging films and includes an improved method and apparatus for Shrinking and sealing such pollen.

The invention can be used, for example, for the packaging of cubes or cuboid, polygonal or cylindrical objects »serve» Such objects were previously under Packaged using semi-automatic or fully automatic packaging machines, most of these suffer Sewing machines have the disadvantage that they are only in use of plastic packaging materials can be used, which have more than one layer. Such Materials have a thermoplastic coating, the melting point of which is significantly lower than that of the Base material, so that a much lower temperature is required to weld the packaging. Because of the relatively high for welding simple thermoplastic temperatures required from the base material without coating existing pollen

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the packaging machines known up to now cannot be used for the charring of such pollen. With the present invention in contrast to an improved packaging machine is proposed, shrunk with the aid of uncoated thermoplastic films and can be welded, .and a shrink "and Verschweißzusatzvorrichtung for use with the currently customary W packaging machines which otherwise coated on the welding of films are suitable.

When welding uncoated thermoplastic pollen, two basic requirements must be met. On the one hand, friction or slippage between the film to be sealed and the welding element or elements used for welding the film must be avoided and, on the other hand, an excessive temperature rise in the film near the weld must be avoided before the film layers to be welded are firmly pressed together. If the first requirement is not met, then, due to mechanical stresses, plastic deformation of the film can occur, and if the second condition is not met, undesirable and unregulated shrinkage can take place. This type of shrinkage occurs due to the molecular orientation of such films _fl

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that is because the polie shrinks when it opens one below that required for Helß welding Temperature lying temperature is heated. It is therefore strive to ensure that the edges of the foil sheet to be welded are held in place before the welding eleaent or the sweat eleent are used.

Hit the invention is a method of packaging and Sealing of objects proposed, which is characterized in that during a first Erhitzungesohrittes the film is only heated so much that it with Overlapping edges remain wrapped around the object that nan during a second heating step the film to a higher one compared to the first heating step Tea temperature heated, and that you then the foil subjected to a third heating step in which the film is subjected to one opposite to the second heating step heated to a higher temperature and completely heat sealed.

The individual heating steps can either be carried out in one device or in different devices will. When the heating steps are carried out in different devices, the device for the the first heating step is a known device,

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while the device for the second and third heating step is a new device according to the invention can be «which can be used together with a known device.

To carry out the method according to the invention suggested that at least two sweats te and one Shrink element, each of which is a heating plate act »act successively on the same part of the film surface to be sealed and that at least the last of the welding elements should be arranged to be movable to and fro, with the shrinkage between the takes place in both heating steps. A welding process with two heating steps not only has the advantage of that the welding time is increased. It is thus possible to use a thermoplastic material that is wrapped around the item to be packaged To first subject the film to a first heating in a device in which it is, for example, a act already known packaging and welding machine can, and then the packaged goods in an inventive Transfer device in which the second and third heating steps take place. When using a thermo » plastic film, e.g. a plasticizer-free polyvinyl chloride film, the film remains during the first heating firm without any deformation if the temperature is below the

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above-mentioned ear body temperature is maintained »but can the foil a certain part of its original blasti forfeiture. It was found that by the first If the film is heated, the tendency is lost for the folded ends to spring open again after the folds.

A convenient way to perform the procedure consists of putting a film around the packaged goods into one Packaging folds, the preheating in a first Er- 'heating station, the packaged goods to shrink the Foil transferred to a second heating station, anechlies * send forwards the packaged goods to a third heating station, where they are subjected to a third heating. the The temperature of the film surfaces to be welded is so low in the first heating station that deformation of the film is avoided while the film is in the third heating station to a temperature sufficient to achieve a perfect weld will. The conveyance of the paokten object between the heating stations should be done in such a way that any unwanted contact between the film and one the heating plates is avoided.

Since in this process catfish the first heating is not for Serves to create a strong and durable seal,

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let it auglloh, the procedure nit a device for to carry out the first roasting tongue step, in which the Foil to be welded slides over heating plates.

The subject of the invention is also a device for "packaging of objects in thermoplastic hot-air gelatinous film" for shrinking the film and for HelS sealing the film, which is identified by a device for folding such a film around the packaged goods, a first heating station in which the Foil is heated so strongly that it remains wrapped around the object with overlapping edges, a second Heating station for heat shrinking the film at a temperature relative to the temperature in the first heating station higher temperature and a third heating station for heating the film to one opposite to the second Heating station for higher temperature and thus for complete welding of the film.

Furthermore, the invention provides an additional device for use with a device for wrapping a Faokgutes in a helßslegelfShig3 thermoplastic film and proposed for heat sealing the film around the article, the attachment being characterized 1st through devices for performing the second and

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The third heating step is enjoyed according to the invention Method without the first heating step, wherein the The device is designed so that it holds the packaged goods from the packaging »and welding device.

Difficulties have hitherto also arisen with the shrinkage of thermoplastic foils enveloping flare material to * whereby the shrinkage usually takes place after the melting. In doing so, the film to be shrunk became Exposed to hot air or infrared heaters or but brought into contact with heated surfaces. In any process in which the shrinkage of a thermoplastic film occurs after the film has melted, Difficulties are caused by the air trapped by the film after welding expands when the film is subsequently heated to achieve shrinkage. This extension of the Air inside the film thus counteracts the desired shrinkage.

It is suggested that a film wrapped around a packaged item prior to the complete welding of the Shrink foil. When the shrinkage is reached in this way, the above-described, by βInge

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closed air did not cause difficulties. If the shrinkage is carried out in this way, a film can be obtained which is properly sealed and is shrunk under controlled conditions, which is not the case with prior art shrinkage methods ntiglioh 1st. It was with the usual procedures up to now For example, it is necessary to perforate the polie before the shrinkage xu, which undoubtedly increases the strength of the film impaired. ■

Ka has also been found in the past that the low heat transfer coefficient between air and the Another disadvantage of shrinking film is “Off this orunde it is favorable to means of the shrinkage to carry out a process that does not require the application of hot air to the film.

If the shrinkage is carried out before the film is completely welded, the entire may possibly be from Air trapped in the film can easily escape through the folds of the film, which are on top of each other and only have been subjected to moderate preheating. To the completion of the shrinkage, it is then possible to completely and firmly weld the Effect slide.

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Because of the low efficiency in the shrinking process, in which hot air is blown against the film is proposed in the context of the present invention, the Shrinking can be carried out by bringing the film to be shrunk into contact with a hot surface, for example a hot plate. The shrinkage naoh this method offers the further advantage that the area of the film to be shrunk is much easier lets control. For example, if it is desired to reduce the shrinkage to a small area of the film limit, e.g. to the part of the film resting against a surface of the packaged goods, this can easily be achieved by only inserting the heating plate in applies to that particular area.

Further advantages are achieved * that the shrinkage is achieved by direct contact; for example, ■ the dimensions of the device used to carry out the method must be smaller than when using hot air and the normally undesired heating of the packaged goods in the film can furthermore be largely suppressed.

A process in which the shrinkage is achieved thereby is that one brings a heated surface into contact with the film to be shrunk, can essentially be two

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various catfish are performed. Either can heated Pläohe be brought into contact with the film without the heated surface on the The point of contact moves in the plane of the film, or the product can slide over the heated surface · When using the latter method, any undesirable deformation and any impairment of the desired properties of the film are avoided because the shrinkage temperature of the film is lower than that Temperature at which the film becomes sticky and excessively plastic will. It is thus possible to achieve the shrinkage while the packaged goods wrapped in the film are in a Device is transferred from one station to the next. However, it is preferable that the between wrapped packaged goods and the pressure prevailing on the heated surface while the product is being conveyed is as low as possible. The pressure can then be increased as soon as the relative movement between the Product and the heated surface stops in order to improve the heat transfer to the film and on this catfish in this way a better and more even shrinkage of the film between the product and the heated surface to reach.

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It has been found that there are two possibilities for including a shrinkage step in a carbonisation process for a film which are particularly favorable. A shrinking station is used in the first working phase Inserted into a packaging machine, in this In case the shrinking station is placed between the preheating station and the final heating station. In the second way of working an additional welding device is used, those for use together with a packaging machine as already mentioned above is intended, in which case the additional device according to the invention is designed for its part in such a way that it contains a shrinking station.

To explain the present invention in more detail the following description of specific designs serve forms shown in the accompanying drawings; show it:

Flg. 1 shows a schematic representation of a packaging machine according to the invention and

Flg. 2 shows a schematic representation of an embodiment the additional device according to the invention with two shrinking stations.

In Fig. 1 is a roll ** 5 with thermoplastic bottom left

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Shown foil / disposed so ,, wherein the rotatability of the roller, as shown in the figure, is limited to a clockwise rotation _r that the PoJie you came to be unwound from the roll by einennach rightward train and the film of the highest point the roll is pulled o A pair of cutting elements is arranged immediately to the right of the roll kj> , consisting of an upper cutting ^{element 44 fl} and a lower cutting element 44, which are designed so that they can be moved up and down like scissors. To the right of the cutting elements 44 and 44 ^! If there is a lifting platform 45 with a flat, horizontal surface, this lifting platform 45 is used to lift the goods to be packaged after they have been wrapped in thermoplastic film.

A folding tool with folding elements 46 and 46 ⁵ is arranged above the lifting platform 45, the elements 46 and 46 'being at points which are equidistant to the right and left of the vertical through the center of the lifting platform 45 - immediately above Located to the left of the folding element 46 is a slide 49 which is designed so that it can exert a force directed to the right on the goods to be packaged, which leads to a displacement of the goods to be packaged; immediately below the slide 49 is a Feltelemeiit 4? _s

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The operation of the slide 49 and the folding element 47 become from the following description of the operation · = expiration of the device become clear after listing the other parts of the device follow below,

The device includes a horizontal table consisting of three parts, namely a left part 48, a middle part 63 and a right part 64. The left part 43 of the table is located immediately above and to the right of the folding element 46 'and the part 48 of the table is provided at its ⁴ left with a downward region "the Paltelement-e 46 and 46 ⁷ each having a curved shape so that the distance between them decreases from bottom to top, wherein the mutually facing sides of the elements convex are shaped. Gaps 65 and 66 are provided between the left part 48 of the table and the middle part 6j5 of the table and between this part of the table and the right part 64 of the table. In the column 65 a welding tool 50 is arranged, which can be brought into contact with the thermoplastic film on the underside of the goods to be packaged when the latter is in the position indicated by AjJ, that is to say

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if it is above the gap 65. In column 66 lies a shrink plate 55, the temperature of which is so high that Q the thermoplastic film shrinks with the plate 55 is brewed in touch. Directly above the plate 55 and at a distance therefrom is a reciprocable Heating plate 56 arranged,

A number of pflugsoharförmigen PUhrungselementen 51 _e 52 and 53 serve to complete the folding of ther ~ tic foil around the Packgutstück.

Below the middle ax 63 of the table to the right of the There is a picking tool on the roll 4j5 mentioned above 42, which is used to pull off a piece of film from the roll 43 served

In the following, the operating sequence in the case of the FIG Embodiment shown in accordance with the invention Device are described. The gripping tool 42 grips the front end of the wound on the roll 4j5 thermoplastic film and then moves to the right in the position shown in the figure. To this k'eise will put a piece of the foil over the top of the too item to be packaged pulled, with see the item to be packaged

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do this tent spot in the in Pig. J- denoted by Al Position is and is on the lift 45. the Cutting elements 44 and 44 'now move towards one another and sever the film at a point near the highest point of the roll 42. After this Cut is a rectangular sheet of film over the top " Side of the packaged goods in the position Al, the right and left areas of this rectangular arch to the Seldom hang down the packaged item "after the Qreifwerkzeug has released the film "Die Hebebühne 45 now lifts the object so that it passes through the space between the folding elements 46 and 46 " and came into the position indicated by A2 in the figure When the packaged goods pass between the elements 46 and 46 'are previously loose on the sides of the packaged goods hanging film areas firmly pressed on its sides » so that the mechanical folding can take place. To this

At the instant, the folding element 47 comes into action and wiaäwie indicated in the figure pushed to the right to ensure that the down on the left side of the packaged goods hanging film part held and in a position above of the film area hanging down on the right side of the packaged goods arrives, whereby it is prevented that the left sheet part is shifted by the folding element 46 'to the left will * if the packaged goods move out of position A2 at the next

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Step of the procedure is pushed to the right. The slide 49 advancing to the right hits the film covering the left side of the packaged goods and pushes the packaged goods out of position A2 into position A? Further. The folding element 45 and the slide 49 are now withdrawn to the left, so that the Peekgut comes to a temporary standstill in the position AJ. In this "position is the packaged product, as shown in the figure _e across the gap 65 between the. left part 48 of the table and the middle part 63 of the table. While the packaged goods are standing still in position AJ, occurs; the welding tool 50 in action "by being raised at the top and brought into contact with the overlapping film areas on the underside of the packaged goods" and 53 vörbeigleitetj, through which the lateral folds are completed ♦

After reaching the position A * i in the figure comes the Packaged goods come to a standstill again. In this position, the heating plates 54 come with animal foils en the front and the Back of the packaged goods in contact <Lie effect of the Heating plate 5 ^ is limited to a preheating, so there /? no welding of the

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Slide takes place ο

After pulling back the heating plates 54 from the foil the packaged goods are conveyed further to the right and arrive finally to position A5. The packaged goods slide over the surface of the base plate 55 and the heating plate 56 is to act on the horizontally lying Top of the slide lowered while sliding the The goods to be packaged over the plate 55 are placed on the underside the film area lying on the packaged goods is subjected to shrinkage »after the treatment between the plates 55 and 50 the process is almost complete and remains only the last step left where the complete The film is welded. This last step takes place when the packaged goods move between the back and forth Hinged heating plates 57 are located, that is to say in of the drawing on the far right in the position marked A6. Awake performing the welding in the Position A6 is the packaging for passing on Uberiiahmestatlon ready, which is not shown in the drawing.

If during the taking place between the plates 55 and 56 Shrinkage between the film and the packaged goods is trapped in any air, so this can easily

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through the side folds of the Poll-2, the have not yet completely blurred at this point of the tent » In this position, any trapped air cannot deform or tear the Guide slide.

In Fig. 2 an embodiment of the device according to the invention is shown, which is to be used in particular as an independent unit together with a conventional packaging machine. When this device is operated, a packaged item that has already been wrapped in a thermoplastic film and whose folds have already been preheated through a lifting platform Jl raised upwards and passed vertically between two vertically arranged heating plates Ό and 74 Figure can be pushed to the right and comes on a horizontal table, which is similar to that _{of Fig 6 1.} In a column of the horizontal table, the lower of two horizontal heating plates 75 and 76 is arranged, which also serve as shrink plates, but act on other outer surfaces of the film enveloping the packaged goods. The film surfaces exposed to the plates 75 and 76 are the horizontal underside and

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the horizontal top surface of the packaging material _e After leaving the plates 75 and 76 reaches the Packßut between the back and herverschiebbaren heating plates 77 are arranged dio vertically and from which _o are behind the PackgutstUck a var and the Andei ^ e herverschiebbaren the reciprocating Plates 77 are used to completely weld the film. After the action of the plates 77, the shrinkage and welding of the film around the item to be packaged is complete.

It is clear that the embodiment shown in Pig, 2 form of a device is particularly valuable if the. Device is used as an accessory to a packaging machine, for example with a packaging machine conventional design.

If any of the previously described devices for welding or for welding and shrinking a thermoplastic film is used, it is possible to use a large number of different types of film, since it is not difficult to determine from the device to meet the requirements to be placed on the film. Βε However, it has been found that a film having good rigidity can be used particularly advantageously if one such film on high-speed packaging machines

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including those that are not based on the use of thermoplastic? ' Films are designed, can be processed. In particular, it has been found that very good results are obtained Kit a film prepared from polyvinyl chloride and its copolymers, dieentweder is completely free of plasticizer or having a low plasticizer content. All gaps in the film can be eliminated if a film that shrinks by 10 to 20 Jß is chosen. A film with a particularly high degree of shrinkage should preferably not be used * since such films generally do not have particularly good weldability.

This is followed by a summary of the temperature ranges and the corresponding polyene properties for the inventive method cde-r the device to be seen as suitable:

70 to 10O ⁰ C "It should be mößlich define the folds by a Vorverschweißung without significant shrinkage, and the film should be smooth sliding over metallic surfaces - this temperature is suitable for setting the FoXienfaltungen" while they slide on a hot plate.

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100 to 115 ° Co The film should have a certain tendency to shrink which, however, should not be too strong »and the Ability to slide across metal surfaces should also be in this temperature range should still be present.

Π5 to 125 ° C. The film should have good shrinkage show, but can still slide over metal surfaces as long as the D.niok is not too high, i.e. as long as the Frictional forces are not so great that a relative movement between the film and the hot surface without damage, the foil is prevented. This temperature range is suitable for shrinking the film through sliding contact with the metal surface,

125 to 145 ° Cc The film should and should shrink well no longer spawns glide over metal surfaces. This Temperature range is suitable for shrinking the film through contact with the sliding heating plates »

150 to l80 ° Co. The film should be very plastic and practically completely lose their mechanical strength and become strongly adhesive in the process. This temperature range is suitable for achieving the final weld, in which the weld is pushed back and forth Heating plates takes place.

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Claims (1)

Claims fli A method of packaging and sealing objects in which a thermoplastic heat-sealable film is wrapped around the object, followed by a first? and a second heating step follows, characterized in that during the first heating step the polish is only heated to such an extent that it remains wrapped around the object with overlapping edges that during the second heating step the polish is higher than in the first heating step Temperature, and that the film is then subjected to a third heating step, in which the film is heated to a higher temperature than the second heating step and completely hot / sealed, 2 _e process according to claim 1, characterized in that *> is I45 ° C heated the Polie during the second S ^ hitzungssehTittes to a temperature in the range of 115 5. The method according to claim 1 or 2, characterized in that that the polie is heated to a temperature in the range from 150 to 180 ° C during the third heating step " 009819/1396 ΘΑ0 ORlOINAL 1S52557 4. The method according to claim 1 to 3 »characterized in that that the foil during the second heating step in contact with shrink plates (55, 56, 73, 74, 75/76) continues " 5. The method according to claim 4, characterized in that that the film is in contact with one or two shrink plates arranged in pairs (55 # 56, 73 »74, 75, 76), of which at least one pair can be pushed back and forth, 6. The method according to claim 1 to 5 »characterized in that that during the third heating step the film is in contact with two pairs of back and forth sliding heating plates (57, 77) continues. 7. Device for performing the method according to claim 1, characterized by a device (46, 46 ^s , 47, 4fc, 51 »52, 53) for folding a film ura a packaged item (A), a first heating station (54) for a heating to a temperature sufficient for fixing <iev wound around the object film with their overlapping edges, a sweite heating station (55 "56, 73» 74, 75 * 76) to shrink the film at a relative to the first heating station higher temperature, 009819/139 6 BATH and a third heating station (55 * 77) for complete heat-sealing of the film at one relative to the temperature in the second heating station higher temperature. 8. Device according to claim 7 »characterized in that that two shrink plates in the second heating station are provided «of which at least one back and forth Is designed to be pushed out. 9 · Additional device for use with a packaging machine, characterized by a heat shrink station, a heat sealing station for heat sealing a thermoplastic film that has been shrunk around a packaged item in the shrink station, as well as a device for taking over a packaged item (A) from the packaging machine, but without devices for folding the film \ around the Packgutstück and without devices for Fixleren of the film in the folded state to the Packgutstück. 10.Vorrichtung according to claim 9, characterized in that that in the heat shrink station heat shrink plates (55 * 56, 73, 7 ^ # 75 * 76) are provided « 009819/1396 0AD ORIGINAL 1S52557 11 »Device according to claim 10, characterized in that there are two pairs arranged in the hot ear tube station Heat shrink panels are provided, with at least one plate of each pair is designed to be slidable back and forth. coll. 009819/1396 ■ A ·. Blank page