Method and apparatus for producing moulded pulp articles with a plastic film laminated thereon

Abstract

The invention relates to an apparatus and method for producing articles ( 5 ) from moulded pulp material that are laminated with a plastic film ( 4 ). Thus an environmental friendly and water-resistant package for food products and for other moulded pulp products such as packages for industrial products is provided. The apparatus comprises a moulding line 1 and a laminating line ( 3 ). The moulding line ( 1 ) comprises a suction moulding station ( 20 ) with a pulp vat ( 25 ) and a number of suction moulds ( 22 ), a drying oven ( 28 ) and conveying means ( 26,28 ) for transporting the moulded pulp articles through the moulding line ( 1 ). The articles are transported in line by a conveyor 10 from the moulding line ( 1 ) to the laminating line ( 3 ), the laminating line ( 3 ) comprises a plastic film supply unit ( 47 ), a heating station ( 69 ) a laminating station ( 80 ) and conveying means ( 56 ) for conveying the articles ( 5 ) through the laminating line ( 3 ).

1 . Apparatus for producing articles ( 5 ) from moulded pulp material that are laminated with a plastic film ( 4 ) comprising a moulding line ( 1 ) and a laminating line ( 3 ), the moulding line ( 1 ) comprising a suction moulding station ( 20 ) with a pulp vat ( 25 ) and a number of suction moulds ( 22 ), a drying oven ( 28 ) and conveying means ( 26 , 27 ) for transporting the moulded pulp articles ( 5 ) through the moulding line ( 1 ), the apparatus further comprises 
 conveying means ( 10 ) for transporting the moulded pulp articles ( 5 ) from the moulding line ( 1 ) to the laminating line ( 3 ) which is arranged in line with the moulding line ( 1 ), thus forming one continuous production line,    the laminating line ( 3 ) comprising a plastic film supply unit ( 47 ), a heating station ( 69 ), a laminating station ( 80 ) and conveying means ( 56 ) for conveying the articles ( 5 ) through the laminating line ( 3 ).    
     
     
         2 . Apparatus according to  claim 1 , wherein the moulding line ( 1 ) is adapted to produce a plurality of articles ( 5 ) that are mutually interconnected.  
     
     
         3 . Apparatus according to  claim 2 , wherein the plurality of interconnected artides ( 5 ) are transported together through the moulding line ( 1 ) and the laminating line ( 3 ).  
     
     
         4 . Apparatus according to any of  claims 1  to  3 , wherein the laminating line ( 3 ) is located separately from the moulding line ( 1 ) in a clean room ( 40 ).  
     
     
         5 . Apparatus according to  claim 4 , characterised in that the conveying means ( 10 ) for transporting the moulded pulp articles ( 5 ) from the moulding line ( 1 ) to the laminating line ( 3 ) passes through an opening ( 43 ) in a wall ( 42 ) separating the laminating line ( 3 ) from the moulding line ( 1 ), whereby preferably a tunnel ( 45 ) is extending from the opening ( 43 ) towards the moulding line ( 1 ) in which tunnel the conveying means ( 10 ) is received.  
     
     
         6 . Apparatus according to any of  claims 1  to  5 , wherein the laminating line ( 1 ) further comprises a hot press station ( 50 ) and a corresponding humidification station ( 30 ) before the heating station ( 69 ).  
     
     
         7 . Apparatus according to any of  claims 1  to  6 , wherein the conveying means ( 10 ) for transporting the moulded pulp articles ( 5 ) from the moulding line ( 1 ) to the laminating line ( 3 ) comprises a buffer of moulded pulp articles ( 5 ).  
     
     
         8 . Apparatus according to any of  claims 1  to  7 , further comprising a means ( 52 , 53 , 54 , 55 ) for positioning the moulded pulp articles ( 5 ) with respect to the hot press station ( 50 ).  
     
     
         9 . Apparatus according to  claim 8 , wherein the moulded pulp articles ( 5 ) are fixed with respect to the conveying means ( 56 ) for transporting the articles ( 5 ) through the laminating line ( 3 ) when the hot press ( 51 ) is closed.  
     
     
         10 . Apparatus according to any of  claims 1  to  9 , wherein the laminating station ( 3 ) further comprises a hot tool ( 85 ) for laminating the plastic film ( 4 ) to selected areas of the moulded pulp articles ( 5 ) in order to weld the film ( 4 ) in these areas to the moulded pulp articles ( 5 ).  
     
     
         11 . Apparatus according to any of  claims 1  to  10 , wherein the laminating station ( 3 ) comprises means for applying underpressure to the film ( 4 ) through the moulded pulp articles ( 5 ) and/or a pressing tool ( 83 ) and/or means for applying overpressure to the film ( 4 ) in order to shape the plastic film ( 4 ) and press it onto the moulded pulp articles ( 5 ) and secure sufficient bonding of the film ( 4 ) to the articles ( 5 ).  
     
     
         12 . Apparatus according to any of  claims 1  to  11 , wherein the moulded pulp articles ( 5 ) or a plurality of interconnected moulded pulp articles ( 5 ) are moulded with laterally protruding tabs or flanges ( 6 ) which are gripped or engaged by the conveying means.  
     
     
         13 . Apparatus according to  claim 12 , wherein the conveying means ( 56 ) for transporting the articles ( 5 ) through the laminating line ( 3 ) engage both the tabs or flanges ( 6 ) of moulded articles ( 5 ) or of the plurality of interconnected moulded pulp articles ( 5 ) and the plastic film ( 4 ) sheet with a common engagement means.  
     
     
         14 . Apparatus according to any of  claims 7  to  13  in which the operation speed of the laminating line ( 3 ) depends on the number of moulded pulp articles ( 5 ) in the buffer.  
     
     
         15 . Apparatus according to any of claims I to  14 , further comprising a film crystallisation station ( 90 ) after the laminating station ( 80 ).  
     
     
         16 . Method of producing moulded pulp articles ( 5 ) with a plastic film ( 4 ) laminated thereon comprising the steps of, 
 providing a pulp vat ( 25 ),    providing at least one suction mould ( 22 ),    submerging at least one suction mould ( 22 ) in the pulp vat ( 25 ),    removing the moulded pulp artides ( 5 ) from the suction mould ( 22 ) and conveying    the moulded pulp articles ( 5 ) through a drying oven ( 28 ) to dry them,    transporting the moulded pulp articles ( 5 ) in line from the drying oven ( 28 ) to a laminating line ( 3 ),    supplying plastic film ( 4 ) to the laminating line ( 3 ),    heating the plastic film ( 4 ) and the moulded pulp articles ( 5 ),    laminating the film ( 4 ) onto the moulded article ( 5 ) and crystallising the plastic film ( 4 ).    
     
     
         17 . Method according to  claim 16 , wherein a plurality of articles ( 5 ) mutually interconnected through bridges are moulded together as an integral body which is conveyed as one entity through the moulding line ( 1 ) and the laminating line ( 3 ).  
     
     
         18 . Method according to  claim 17 , wherein the moulded pulp articles ( 5 ) or a plurality of interconnected moulded pulp articles ( 5 ) are moulded with laterally protruding tabs or flanges ( 6 ) which are gripped or engaged by the conveying means ( 10 ).