CA1171775A - Process for manufacturing a metallized composite band and band obtained with such a process - Google Patents
Process for manufacturing a metallized composite band and band obtained with such a processInfo
- Publication number
- CA1171775A CA1171775A CA000367535A CA367535A CA1171775A CA 1171775 A CA1171775 A CA 1171775A CA 000367535 A CA000367535 A CA 000367535A CA 367535 A CA367535 A CA 367535A CA 1171775 A CA1171775 A CA 1171775A
- Authority
- CA
- Canada
- Prior art keywords
- pellicle
- band
- film
- plastic material
- plastic
- 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.)
- Expired
Links
Classifications
-
- 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
- B65D25/00—Details of other kinds or types of rigid or semi-rigid containers
- B65D25/14—Linings or internal coatings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0017—Combinations of extrusion moulding with other shaping operations combined with blow-moulding or thermoforming
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
- B29C48/08—Flat, e.g. panels flexible, e.g. films
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
The invention relates to a process for continuously manufacturing a composite band comprising a plastic sheet bonded to an aluminized pellicle, these two components consisting in separate bands before carrying out the process. The composite band issued of the process can be used for instance for insula-ting or padding. This band can also be used after cutting and thermoforming as pan or container for perishable products such as meat. The perishable product is put in the pan and both are covered with a plastic film to give a stocking and hygienic presentation. To carry out the process and to bond the basic plastic band (expanded polystyrene) to aluminized pellicle, these two sheets are introduced between calendering cylinders with interposing between the two sheets an intermediate film of plastic material at softening temperature to provide the adhe-sion. Of course, it is the non aluminized side of the pellicle which is in contact with the polystyrene basic band.
The invention relates to a process for continuously manufacturing a composite band comprising a plastic sheet bonded to an aluminized pellicle, these two components consisting in separate bands before carrying out the process. The composite band issued of the process can be used for instance for insula-ting or padding. This band can also be used after cutting and thermoforming as pan or container for perishable products such as meat. The perishable product is put in the pan and both are covered with a plastic film to give a stocking and hygienic presentation. To carry out the process and to bond the basic plastic band (expanded polystyrene) to aluminized pellicle, these two sheets are introduced between calendering cylinders with interposing between the two sheets an intermediate film of plastic material at softening temperature to provide the adhe-sion. Of course, it is the non aluminized side of the pellicle which is in contact with the polystyrene basic band.
Description
~.71'775 The present invention relates to a process for ~anu-facturing a composite band used for instance to make a packing article of the pan type for perishable products, such ac fresh meat and other foodstuffs, said article being conceived in order to enable the stocking and hygienic presentation of such products beneath a synthetic film enveloping the pan and the product.
Packing articles of this type are known which are composed of a bottom of plastic material connected to a metallic coating on its interior surface which is intended to come into contact with the packed product. The internal coating is generally composed of a metallic sheet which is laid on or struck to the bottom. Such articles are expansive to manufacture since they require the use of a metal which is compatible with the foodstuffs, in particular aluminium.
In its most general embodiment, the present invention relates to a process for manufacturing an article of this type which has a low cost and is simple to manufacture, wherein the metallic coating is applied to its support by vacuum pulveri-zation of metallic particles, and in particular aluminium, whichallows for the use of a metallic deposit of very diminished thickness.
In accordance with one or more particular and preferred embodiment, the pulverisation if effected onto a pellicle intimately contacted by welding to the support which itself is made of expanded polystyrene. A polystyrene pellicle pre-aluminized on one of its surfaces could be used.
The manufacture of such an article can be carried out by direct projection of aluminium particles onto the support but such an operation has the disadvantage of necessitating a ~71'~75 metallic deposit of non-negligible thickness and of limiting the rythm of manufacture. For this reason, the invention relates to a much more economical process which allows manu-facture of such articles at high speed.
The present invention provides a process for the manu-facture of a composite band, said band comprising an element of plastic material and a metallic coating covering at least one of the surfaces of the element with which said coating is bonded, characterized in that . a pellicle of plastic material with a single metallized surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing betweenthe elément and the non-metallized surface of the pellicle an intermediate bonding film of plastic material main-tained at a temperature ensuring at least superfi-cially its softening and providing adhesion of the film with the plastic material of the element and of the pellicle.
The present invention also provides a process for the manufacture of composite articles from a composite band, said band comprising an element of plastic material and a metallic coating covering at least one of the surfaces of the element with which said coating is bonded, characterized in that a pellicle of plastic material with a single metalli-zed surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing between the element - la -~,~,t~, ~L775 and the non-metallized surface of the pellicle an intermediate bonding film of plastic material maintained at a temperature ensuring at least superfi-cially its softening and providing adhesion of the film with the plastic material of the element and of the pellicle, and wherein . the metallic coating is a coating of aluminium . the element of plastic material and an aluminized pellicle in the form of continuous separated bonds are simultaneously circulated between calendering cylinders, the non-aluminized surface of the element being opposite, the non-aluminized surface of the pellicle.
. a continuous intermediate bonding film of plastic material is extruded and inserted between the element and the non-aluminized surface of the pellicle while maintaining said film at a temperature at least equal to its softening point, . following which thermoforming and cutting of the compo-site band are carried out in order to obtain the articles.
The present invention further provides a composite metallized plastic band comprising a plastic band of a thickness of about 3 mm, an aluminized pellicle of a thickness of about 25 microns fixed by its non-metallized face to the plastic band by interposition of an intermediate plastic bonding film of a thickness of about 30 microns.
In its most general embodiment, and this applies both for manufacture of an article in a continuous band and of a - lb -1~7~775 plurality of articles of limited dimensions, such as pans, the process of the present invention is characterized by the fact that a pellicle of thin plastic material is used, wherein one single surface is metallized by any known appropriate forces, for example, by vaccum pulverization of metallic par-ticles, and the bonding of the plastic material base element and the metallized surface of the pellicle is carried out by interposing between them an intermediate film of plastic material which is maintained at a temperature ensuring its softening, at least superficially, and providing adhesion of said film with the material of the element and of the pellicle, the bonding being effected under the action of at least local pressure in the bonding zone. The use of a metallized plastic material pellicle enables the use of only ~ery little metal, in a layer of only a few hundredths or thousandths of.microns, mechanical resistance being provided by the pellicle of plastic material which, also, will preferably be of diminished thickness (for example less than 30 ~). ~
.. . . .
~ 7177S
Howewer, when working with a metallized pellicle of such diminished thickness, experience has shown that it is practically impossible to obtain a direct weld of the pellicle onto the plastic material base element.
Indeed, on the one hand, in order to obtain good bonding, the plastic materials to be contacted must be made adhesive by provision of considerable heat, but, on the other hand, this provision of heat risks deteriorating the metallic layer. The interposition of an intermediate film recommended by the process of the invention enables this paradox to be resolved under excellent conditions. To do this, at the time of bonding, the surfaces of the intermediate filrn are at a tempe-rature such that the material of the film is in a sticky state, at least superficially, whereas the surfaces of the base element and of the peilicle which are intended to be contacted with the film are heated to a temperature below the softening temperature of the material of which they are composed.
This avoids bringing the metallized layer to an excessive temperature which would cause its deterioration, in particular in the preferred embodiment in which aluminium is used.
An advantage of the process of the present invention is that a pluraiity of composite articles can be continuously manufactured from the plastic material base element and from a metal-lized (for example, aluminized) pellicle which are in the form of continuous separate bands.
In the case, and in accordance with the invention, - the element and the aluminized pellicle are unrolled simultaneously and are circu-lated between calendering cylinders, the non-aluminized surface of the pellicle being opposite the element band, - and the continuous plastic material film which is inserted between the element and the non aluminized surface of the pellicle is extruded while maintaining it at a temperature at least equal to its softening point, - after which thermoforming and cutting of the composite band are carried out in to obtain articles such as containers or pans.
Naturally, the plastic materials used should be compatible and according to one em-bodiment of the invention, the base element will be of expanded polystyrene whereas the metallized pellicle wil! be composed of a polystyrene film coated with a layer of aluminium, the intermediate film also being of non-expanded polystyrene (impact or semi-impact polystyreneJ.The invention is described by reference to the attached drawings which are given as non-limitative examples, and in which:
Figure 1 represents a perspective view, partially cut away, of a packing pan obtained in accordance with the preferred process of the invention;
F;gure 2 represents schematically a transversal cross section of the composite band (the pan of Figure 1 );
Figure 3 is a cut perspective detail showing the means for delivering the intermediate film;
Figure 4 shows, schematically, on a enlarged scale, the means of the bonding zone; and Figure 5 is a schematic perspective view on a larger scale of the calender of the ma-chine.
At present the carrying out of the process of the invention will be described.
An expanded polystyrene band 16 of a thickness of approximately 3 mm is pulled bya classical traction apparatus which is followed by a calender 20. Between the traction appar atus and the calender is situated the flat head 23 of an extruder delivering the intermediate polystyrene film.
The aluminized pellicle 27 of a thickness on the order of 25 )J(see Figure 5) is un-wound from a ro!ler 26 mounted on an axis 25 supported by the frame of the machine, in such a manner that the aluminium layer is on the interior surface 28, the polystyrene film 29 being on the exterior. The pellicle 27 is guided onto a roller 30.
Before reaching the calender 20, the polystyrene film 29 of pellicle 27 is warmed by a heating system 32 (for example, infrared) to a temperature of 70, 85 C. Similarly, the exterior surface of the band 16 is heated in the same manner to a temperature of 80 to 95 C, which tem-perature is lower than the softening temperature of polystyrene.
The cylinders 33, 34, 35 of the calender are supported by a frame 36 and at least the two lower cylinders 33 and 34 are adjustable one in relation to the other in order to adjust the space 20 E which separates them.
For this purpose, the axes of these cylinders may be housed in the bearings 37 sliding in the frame 36 under the effect of jacks 38.
The distance E between the cylinders 33 and 34 is adjusted so as to be slightly less than the thickness of the band 16 so as to exert pressure on the assembly of the bands at the time of bonding. In the example shown, the pressure exerted between the cylinders in the bonding zone is approximately 4 to 5 kg.
The flat head 23 of the extruder which delivers the intermediate film 40 is mounted upstream from the calender. This head, which has a length at least equal to that of the band 16, has two practically parallel lips 45, 46 which are separated by a distance "e" which, in the case of manu-30 facture of the pan of Figure 1, provides continuous delivery of a polystyrene film of a thickness ofapproximately 30 IJ .
Preferably, lip 46 is semi-rigid and the distance "e" can be modified from place to place by adjustrnent screws 47 inserted into tappings in a fixed plate 48 where the free end presses on lip 46. In this manner the length of the output of the head can be modulated.The output port of the head is situated in a transversal plane (practically perpendicu-lar) to the vertical plane passing by the axes of the calender cylinders and between the genera-" .
'775 tors opposite cylinders 33 and 34 In addition, this output port should be as near as possible to the contact zone betweenthe band 16 and the pellicle 27. In the example shown, this port is situated at less tha n 5 cm from this zone and preferably between 2 and 2,5 cm. The temperature of the head exceeds 200 C and preferably is regulated between 225 and 240 C.
Morcover, cylinders 34 and 35 are heated to a temperature of between 90 and 110 C
according to the thickness of the aluminized pellicle and preferably between 94 and 104 C for a pellicle thickness of approximately 25~'.
However, cylinder 33 is cooled to remain at the ambient temperature of approximately 20 to 35 C.
The heating and cooling of the cylinders 34, 35, 33, can be effected by heating or coo-ling fluid circulation in the hollow interior 34',35',33', of the cylinders.
By appropriate adjustment of the temperatures at the level of the calender, good adhe-sion of the various layers can be effected without deterioration of the aluminium, particularly with respect to its appearance.
This is due to the fact that the aluminized pellicle is maintained by cylinder 34 at a sufficiently low temperature so as not to deteriorate the metal. However, this temperature is not sufficient to provide the softening of the polystyrene pellicle necessary for bonding. The provision of additional temperature is furnished by the film 40 which is in a surface tacky state. The provision of 20 temperature remains nevertheless within limits preventing the deterioration of the metal since a large part of the temperature of the film is absorbed by the expanded polystyrene 15 and by the cooled cylinder 33.
On exit from the calender, the band composed of the aluminized pellicle bonded to the expanded polystyrene band is either wound on a winder to be stocked while awaiting use, as insu-lating and decorative material for example, or directly conveyed under a pressing and cutting unit not represented here which carries out the forming (preferably by heat) and the cutting of the band in order to obtain a plurality of pans such as that shown in Figure 1.
Figure 1 shows a pan for the packing of edible products, for example meat, intended to be completed, after the placing of the product, with an envelope (plastic film) covering both the 30 product and the pan. This pan, made in accordance with the preferred process of the invention after thermoforrning and cutting of the composite band obtained, comprises a base element 1 made of expanded polystyrene which insures the mechanical holding of the article. The interior surface of the pan is covered with anoluminized pellicle composed of a polystyrene film 2a preferably bioriented whose exterior surface (see Figure 2) is aluminized, i.e., coated with a layer of aluminium 2b by any known appropriate process. This layer can be of a thickness on the order of 0.05 to 0.1 ~ .
117~775 This film is transparent and after aluminization, the aluminized pellicle 2 is shiny on both its surfaces. If the exterior surface of the pellicle covering ~he pan is scratched, the shiny alu-minium layer is removed and the milky white color of the expanded polystyrene appears there-through.
Between the pellicle 2 and the expanded polystyrene element 1 an intermediate polystyrene film 3 is interposed which serves as an addition material to ensure bonding during lhe weld of the assembly as indicated above.
When an attempt is made to detach the film on the completed pan, as is shown in Figure 1, the material of the film 3 is adhesive to the polystyrene of the pellicle. The interior surface 10 4 of the detached part indeed has a whitish appearance which is duller than the natural surface 2a of the pellicle. This is a sign that the film 3 is well adhered to the pellicle 2. By carefully scratching the interior surface 4 of the detached part, the film 3 can be removed and the original shiny appearance of the pellicle 2 reappears.
The adhesion of the film to the expanded polystyrene is less strong due to the alveolar structure of the expanded polystyrene.
It will be noted that preferably depressions D ~Figures 1 ) are formed in the metallized surface of the pan and said depressions comprise micro-channels intended to hold any blood which are no longer spread out, without, however, degrading the product by contact with said fluids. The "absorbent" effect of these micro-channels is such that, even if overturned, the fluid spread along 20 said micro-channels does not move and remains the "captive' of these capillary channels. Addi-tionally, these channels can be in the form of grooves or of checkering. The bottom of the depres-sions D remains separated from the packed foodstuff which rests only on the upward projecting parts of the bottom.
Packing articles of this type are known which are composed of a bottom of plastic material connected to a metallic coating on its interior surface which is intended to come into contact with the packed product. The internal coating is generally composed of a metallic sheet which is laid on or struck to the bottom. Such articles are expansive to manufacture since they require the use of a metal which is compatible with the foodstuffs, in particular aluminium.
In its most general embodiment, the present invention relates to a process for manufacturing an article of this type which has a low cost and is simple to manufacture, wherein the metallic coating is applied to its support by vacuum pulveri-zation of metallic particles, and in particular aluminium, whichallows for the use of a metallic deposit of very diminished thickness.
In accordance with one or more particular and preferred embodiment, the pulverisation if effected onto a pellicle intimately contacted by welding to the support which itself is made of expanded polystyrene. A polystyrene pellicle pre-aluminized on one of its surfaces could be used.
The manufacture of such an article can be carried out by direct projection of aluminium particles onto the support but such an operation has the disadvantage of necessitating a ~71'~75 metallic deposit of non-negligible thickness and of limiting the rythm of manufacture. For this reason, the invention relates to a much more economical process which allows manu-facture of such articles at high speed.
The present invention provides a process for the manu-facture of a composite band, said band comprising an element of plastic material and a metallic coating covering at least one of the surfaces of the element with which said coating is bonded, characterized in that . a pellicle of plastic material with a single metallized surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing betweenthe elément and the non-metallized surface of the pellicle an intermediate bonding film of plastic material main-tained at a temperature ensuring at least superfi-cially its softening and providing adhesion of the film with the plastic material of the element and of the pellicle.
The present invention also provides a process for the manufacture of composite articles from a composite band, said band comprising an element of plastic material and a metallic coating covering at least one of the surfaces of the element with which said coating is bonded, characterized in that a pellicle of plastic material with a single metalli-zed surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing between the element - la -~,~,t~, ~L775 and the non-metallized surface of the pellicle an intermediate bonding film of plastic material maintained at a temperature ensuring at least superfi-cially its softening and providing adhesion of the film with the plastic material of the element and of the pellicle, and wherein . the metallic coating is a coating of aluminium . the element of plastic material and an aluminized pellicle in the form of continuous separated bonds are simultaneously circulated between calendering cylinders, the non-aluminized surface of the element being opposite, the non-aluminized surface of the pellicle.
. a continuous intermediate bonding film of plastic material is extruded and inserted between the element and the non-aluminized surface of the pellicle while maintaining said film at a temperature at least equal to its softening point, . following which thermoforming and cutting of the compo-site band are carried out in order to obtain the articles.
The present invention further provides a composite metallized plastic band comprising a plastic band of a thickness of about 3 mm, an aluminized pellicle of a thickness of about 25 microns fixed by its non-metallized face to the plastic band by interposition of an intermediate plastic bonding film of a thickness of about 30 microns.
In its most general embodiment, and this applies both for manufacture of an article in a continuous band and of a - lb -1~7~775 plurality of articles of limited dimensions, such as pans, the process of the present invention is characterized by the fact that a pellicle of thin plastic material is used, wherein one single surface is metallized by any known appropriate forces, for example, by vaccum pulverization of metallic par-ticles, and the bonding of the plastic material base element and the metallized surface of the pellicle is carried out by interposing between them an intermediate film of plastic material which is maintained at a temperature ensuring its softening, at least superficially, and providing adhesion of said film with the material of the element and of the pellicle, the bonding being effected under the action of at least local pressure in the bonding zone. The use of a metallized plastic material pellicle enables the use of only ~ery little metal, in a layer of only a few hundredths or thousandths of.microns, mechanical resistance being provided by the pellicle of plastic material which, also, will preferably be of diminished thickness (for example less than 30 ~). ~
.. . . .
~ 7177S
Howewer, when working with a metallized pellicle of such diminished thickness, experience has shown that it is practically impossible to obtain a direct weld of the pellicle onto the plastic material base element.
Indeed, on the one hand, in order to obtain good bonding, the plastic materials to be contacted must be made adhesive by provision of considerable heat, but, on the other hand, this provision of heat risks deteriorating the metallic layer. The interposition of an intermediate film recommended by the process of the invention enables this paradox to be resolved under excellent conditions. To do this, at the time of bonding, the surfaces of the intermediate filrn are at a tempe-rature such that the material of the film is in a sticky state, at least superficially, whereas the surfaces of the base element and of the peilicle which are intended to be contacted with the film are heated to a temperature below the softening temperature of the material of which they are composed.
This avoids bringing the metallized layer to an excessive temperature which would cause its deterioration, in particular in the preferred embodiment in which aluminium is used.
An advantage of the process of the present invention is that a pluraiity of composite articles can be continuously manufactured from the plastic material base element and from a metal-lized (for example, aluminized) pellicle which are in the form of continuous separate bands.
In the case, and in accordance with the invention, - the element and the aluminized pellicle are unrolled simultaneously and are circu-lated between calendering cylinders, the non-aluminized surface of the pellicle being opposite the element band, - and the continuous plastic material film which is inserted between the element and the non aluminized surface of the pellicle is extruded while maintaining it at a temperature at least equal to its softening point, - after which thermoforming and cutting of the composite band are carried out in to obtain articles such as containers or pans.
Naturally, the plastic materials used should be compatible and according to one em-bodiment of the invention, the base element will be of expanded polystyrene whereas the metallized pellicle wil! be composed of a polystyrene film coated with a layer of aluminium, the intermediate film also being of non-expanded polystyrene (impact or semi-impact polystyreneJ.The invention is described by reference to the attached drawings which are given as non-limitative examples, and in which:
Figure 1 represents a perspective view, partially cut away, of a packing pan obtained in accordance with the preferred process of the invention;
F;gure 2 represents schematically a transversal cross section of the composite band (the pan of Figure 1 );
Figure 3 is a cut perspective detail showing the means for delivering the intermediate film;
Figure 4 shows, schematically, on a enlarged scale, the means of the bonding zone; and Figure 5 is a schematic perspective view on a larger scale of the calender of the ma-chine.
At present the carrying out of the process of the invention will be described.
An expanded polystyrene band 16 of a thickness of approximately 3 mm is pulled bya classical traction apparatus which is followed by a calender 20. Between the traction appar atus and the calender is situated the flat head 23 of an extruder delivering the intermediate polystyrene film.
The aluminized pellicle 27 of a thickness on the order of 25 )J(see Figure 5) is un-wound from a ro!ler 26 mounted on an axis 25 supported by the frame of the machine, in such a manner that the aluminium layer is on the interior surface 28, the polystyrene film 29 being on the exterior. The pellicle 27 is guided onto a roller 30.
Before reaching the calender 20, the polystyrene film 29 of pellicle 27 is warmed by a heating system 32 (for example, infrared) to a temperature of 70, 85 C. Similarly, the exterior surface of the band 16 is heated in the same manner to a temperature of 80 to 95 C, which tem-perature is lower than the softening temperature of polystyrene.
The cylinders 33, 34, 35 of the calender are supported by a frame 36 and at least the two lower cylinders 33 and 34 are adjustable one in relation to the other in order to adjust the space 20 E which separates them.
For this purpose, the axes of these cylinders may be housed in the bearings 37 sliding in the frame 36 under the effect of jacks 38.
The distance E between the cylinders 33 and 34 is adjusted so as to be slightly less than the thickness of the band 16 so as to exert pressure on the assembly of the bands at the time of bonding. In the example shown, the pressure exerted between the cylinders in the bonding zone is approximately 4 to 5 kg.
The flat head 23 of the extruder which delivers the intermediate film 40 is mounted upstream from the calender. This head, which has a length at least equal to that of the band 16, has two practically parallel lips 45, 46 which are separated by a distance "e" which, in the case of manu-30 facture of the pan of Figure 1, provides continuous delivery of a polystyrene film of a thickness ofapproximately 30 IJ .
Preferably, lip 46 is semi-rigid and the distance "e" can be modified from place to place by adjustrnent screws 47 inserted into tappings in a fixed plate 48 where the free end presses on lip 46. In this manner the length of the output of the head can be modulated.The output port of the head is situated in a transversal plane (practically perpendicu-lar) to the vertical plane passing by the axes of the calender cylinders and between the genera-" .
'775 tors opposite cylinders 33 and 34 In addition, this output port should be as near as possible to the contact zone betweenthe band 16 and the pellicle 27. In the example shown, this port is situated at less tha n 5 cm from this zone and preferably between 2 and 2,5 cm. The temperature of the head exceeds 200 C and preferably is regulated between 225 and 240 C.
Morcover, cylinders 34 and 35 are heated to a temperature of between 90 and 110 C
according to the thickness of the aluminized pellicle and preferably between 94 and 104 C for a pellicle thickness of approximately 25~'.
However, cylinder 33 is cooled to remain at the ambient temperature of approximately 20 to 35 C.
The heating and cooling of the cylinders 34, 35, 33, can be effected by heating or coo-ling fluid circulation in the hollow interior 34',35',33', of the cylinders.
By appropriate adjustment of the temperatures at the level of the calender, good adhe-sion of the various layers can be effected without deterioration of the aluminium, particularly with respect to its appearance.
This is due to the fact that the aluminized pellicle is maintained by cylinder 34 at a sufficiently low temperature so as not to deteriorate the metal. However, this temperature is not sufficient to provide the softening of the polystyrene pellicle necessary for bonding. The provision of additional temperature is furnished by the film 40 which is in a surface tacky state. The provision of 20 temperature remains nevertheless within limits preventing the deterioration of the metal since a large part of the temperature of the film is absorbed by the expanded polystyrene 15 and by the cooled cylinder 33.
On exit from the calender, the band composed of the aluminized pellicle bonded to the expanded polystyrene band is either wound on a winder to be stocked while awaiting use, as insu-lating and decorative material for example, or directly conveyed under a pressing and cutting unit not represented here which carries out the forming (preferably by heat) and the cutting of the band in order to obtain a plurality of pans such as that shown in Figure 1.
Figure 1 shows a pan for the packing of edible products, for example meat, intended to be completed, after the placing of the product, with an envelope (plastic film) covering both the 30 product and the pan. This pan, made in accordance with the preferred process of the invention after thermoforrning and cutting of the composite band obtained, comprises a base element 1 made of expanded polystyrene which insures the mechanical holding of the article. The interior surface of the pan is covered with anoluminized pellicle composed of a polystyrene film 2a preferably bioriented whose exterior surface (see Figure 2) is aluminized, i.e., coated with a layer of aluminium 2b by any known appropriate process. This layer can be of a thickness on the order of 0.05 to 0.1 ~ .
117~775 This film is transparent and after aluminization, the aluminized pellicle 2 is shiny on both its surfaces. If the exterior surface of the pellicle covering ~he pan is scratched, the shiny alu-minium layer is removed and the milky white color of the expanded polystyrene appears there-through.
Between the pellicle 2 and the expanded polystyrene element 1 an intermediate polystyrene film 3 is interposed which serves as an addition material to ensure bonding during lhe weld of the assembly as indicated above.
When an attempt is made to detach the film on the completed pan, as is shown in Figure 1, the material of the film 3 is adhesive to the polystyrene of the pellicle. The interior surface 10 4 of the detached part indeed has a whitish appearance which is duller than the natural surface 2a of the pellicle. This is a sign that the film 3 is well adhered to the pellicle 2. By carefully scratching the interior surface 4 of the detached part, the film 3 can be removed and the original shiny appearance of the pellicle 2 reappears.
The adhesion of the film to the expanded polystyrene is less strong due to the alveolar structure of the expanded polystyrene.
It will be noted that preferably depressions D ~Figures 1 ) are formed in the metallized surface of the pan and said depressions comprise micro-channels intended to hold any blood which are no longer spread out, without, however, degrading the product by contact with said fluids. The "absorbent" effect of these micro-channels is such that, even if overturned, the fluid spread along 20 said micro-channels does not move and remains the "captive' of these capillary channels. Addi-tionally, these channels can be in the form of grooves or of checkering. The bottom of the depres-sions D remains separated from the packed foodstuff which rests only on the upward projecting parts of the bottom.
Claims (13)
1. Process for the manufacture of a composite band, said band comprising an element of plastic material and a me-tallic coating covering at least one of the surfaces of the element with which said coating is bonded, characterized in that a pellicle of plastic material with a single metallized surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing between the element and the non-metallized surface of the pellicle an intermediate bonding film of plastic material maintained at a temperature ensuring at least superficially its softening and providing adhesion of the film with the plastic material of the ele-ment and of the pellicle.
2. The process of claim 1 wherein, before the bonding is carried out, at least the surface of the element and of the pellicle which are intended to contact the intermediate film are heated to a temperature lower than the softening tempe-rature of the material of which they are composed.
3. The process of claim 1 or 2 wherein the metallic coating is an aluminium coating.
4. Process for the manufacture of composite articles from a composite band , said band comprising an element of plastic material and a metallic coating covering at least one one of the surfaces of the element with which said coating is bonded, characterized in that a pellicle of plastic material with a single metal-lized surface is used, and bonding of the element and the pellicle is carried out in a bonding zone by exerting pressure on an assembly obtained by interposing between the element and the non-metallized surface of the pellicle an intermediate bonding film of plastic material maintained at a temperature ensuring at least super-ficially its softening and providing adhesion of the film with the plastic material of the element and of the pellicle, and wherein the metallic coating is a coating of aluminium the element of plastic material and an aluminized pellicle in the form of continuous separated bonds are simultaneously circulated between calendering cylinders, the non-aluminized surface of the element being opposite, the non-aluminized surface of the pellicle.
a continuous intermediate bonding film of plastic material is extruded and inserted between the ele-ment and the non-aluminized surface of the pellicle while maintaining said film at a temperature at least equal to its softening point, following which thermoforming and cutting of the composite band are carried out in order to obtain the articles.
a continuous intermediate bonding film of plastic material is extruded and inserted between the ele-ment and the non-aluminized surface of the pellicle while maintaining said film at a temperature at least equal to its softening point, following which thermoforming and cutting of the composite band are carried out in order to obtain the articles.
5. The process of claim 4 wherein the plastic mate-rial of the element is expansed polystyrene whereas the alumi-nized pellicle is a film of bidirectional polystyrene coated with a layer of aluminium.
6. The process of claim 5 wherein the intermediate bonding film is also composed of polystyrene.
7. The process of claim 6 wherein for the calendering operation:
at least the cylinder in contact with the aliminium layer is heated to a temperature of between 90 and 110°C.
the distance between the cylinders is adjusted to a size slightly less than the thickness of the polystyrene element, and pressure of between 4 and 5 kg is exerted between the cylinders.
at least the cylinder in contact with the aliminium layer is heated to a temperature of between 90 and 110°C.
the distance between the cylinders is adjusted to a size slightly less than the thickness of the polystyrene element, and pressure of between 4 and 5 kg is exerted between the cylinders.
8. The process of claim 7 wherein the head of the intermediate bonding film extruder is maintained at a tempera-ture of between 225 and 240°C.
9. The process of claim 8 wherein the distance from the output of the head and the contact zone between the element and the alumininized pellicle is less than 5 centimeters.
10. The process of any one of claims 4, 5 and 6 wherein the composite articles are pans suitable for packing meat products.
11. The process of any one of claims 7, 8 and 9 wherein the composite articles are pans suitable for packing meat products.
12. Composite metallized plastic band comprising a plastic band of a thickness of about 3 mm, an aluminized pellicle of a thickness of about 25 microns fixed by its non-metallized face to the plastic band by interposition of an intermediate plastic bonding film of a thickness of about 30 microns.
13. Composite metallized plastic band of claim 12 wherein the plastic band is of expanded polystyrene and the intermediate film is composed of polystyrene.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7932039 | 1979-12-28 | ||
| FR7932039A FR2473418A1 (en) | 1979-12-28 | 1979-12-28 | Packaging tray of metallised and expanded polystyrene film laminate - using prefabricated vacuum-coated film to speed production and minimise metal content |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1171775A true CA1171775A (en) | 1984-07-31 |
Family
ID=9233313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000367535A Expired CA1171775A (en) | 1979-12-28 | 1980-12-24 | Process for manufacturing a metallized composite band and band obtained with such a process |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5746827A (en) |
| CA (1) | CA1171775A (en) |
| FR (1) | FR2473418A1 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53139679A (en) * | 1977-05-11 | 1978-12-06 | Sekisui Plastics | Method for making laminated sheet |
-
1979
- 1979-12-28 FR FR7932039A patent/FR2473418A1/en active Granted
-
1980
- 1980-12-22 JP JP55181767A patent/JPS5746827A/en active Pending
- 1980-12-24 CA CA000367535A patent/CA1171775A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2473418A1 (en) | 1981-07-17 |
| FR2473418B3 (en) | 1982-10-08 |
| JPS5746827A (en) | 1982-03-17 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |