Cap for a container and related method for making it

Abstract

A cap for a container and related method for making it, wherein the cap includes a cup-shaped body made of metal material, having a skirt which extends around an axis and a transversal wall positioned transversally to the axis, the cup-shaped body on the inside defining a cavity interposed between an inner surface of the skirt and an inner surface of the transversal wall; a gasket housed in the cavity and engaged with at least the inner surface of the transversal wall, the gasket having a peripheral portion configured to couple in a fluidtight way to a mouth of the container; the gasket is made with a natural fibre-based material comprising at least 30% cellulose by weight, the gasket having a modulus of compression of between 0.5 and 50 Mpa.

1 . A cap for a container comprising:
 a cup-shaped body ( 3 ) having a skirt ( 4 ) which extends around an axis (X) and a transversal wall ( 5 ) positioned transversally to the axis (X), said cup-shaped body ( 3 ) on the inside defining a cavity ( 6 ) interposed between an inner surface ( 4   a ) of the skirt ( 4 ) and an inner surface ( 5   a ) of the transversal wall ( 5 );   a gasket ( 10 ) housed in the cavity ( 6 ) and engaged with at least the inner surface ( 5   a ) of the transversal wall ( 5 ), said gasket ( 10 ) having a peripheral portion ( 11 ) configured to couple in a fluidtight way to a mouth ( 2   a ) of the container ( 2 );   wherein the gasket ( 10 ) is made with a natural fibre-based material comprising at least 30% cellulose by weight, said gasket ( 10 ) having a modulus of compression of between 0.5 and 50 Mpa.   
     
     
         2 . The cap according to  claim 1 , wherein said natural fibre-based material comprises at least 70% cellulose by weight. 
     
     
         3 . The cap according to  claim 1 , wherein said gasket ( 10 ) has a hardness of between 50 and 90 SHORE A. 
     
     
         4 . The cap according to  claim 1 , wherein the cap also comprises an adhesive layer interposed between a contact surface ( 10   a ) of the gasket ( 10 ) on the opposite side to the mouth ( 2   a ) of the container ( 2 ) and the inner surface ( 5   a ) of the transversal wall ( 5 ). 
     
     
         5 . The cap according to  claim 1 , wherein said gasket ( 10 ) also comprises at least one barrier layer ( 15 ), positioned at said peripheral portion ( 11 ) and directed towards the mouth ( 2   a ) of the container ( 2 ). 
     
     
         6 . The cap according to  claim 1 , wherein the gasket ( 10 ) has an annular shape and extends in a planar fashion. 
     
     
         7 . The cap according to  claim 1 , wherein the gasket ( 10 ) has a disk-shaped body ( 14 ), said peripheral portion ( 11 ) being defined by a circular and perimetric zone of the disk-shaped body ( 14 ). 
     
     
         8 . The cap according to  claim 1 , wherein said peripheral portion ( 11 ) comprises an annular surface ( 13 ) for contact with an edge ( 2   b ) of the mouth ( 2   a ) of the container ( 2 ). 
     
     
         9 . The cap according to claim  10 , wherein said peripheral portion ( 11 ) of the gasket ( 10 ) is constrained by mechanical interlocking to the inner surface ( 4   a ) of the skirt ( 4 ). 
     
     
         10 . The cap according to  claim 1  wherein the natural fibre-based material comprises at least one hydrophobic component. 
     
     
         11 . The cap according to  claim 1  wherein the natural fibre-based material comprises at least one water-soluble component combined with at least one hydrophobic component. 
     
     
         12 . The cap according to  claim 10 , wherein the hydrophobic component is integrated inside the natural fibre-based material and/or applied as a layer, and wherein the water-soluble component is applied in a layer to be protected by said hydrophobic component. 
     
     
         13 . The cap according to  claim 1 , wherein said cup-shaped body ( 3 ) is made with a natural fibre-based material comprising at least 30% cellulose by weight. 
     
     
         14 . The cap according to  claim 13 , wherein said natural fibre-based material of the cup-shaped body ( 3 ) has an average density greater than or equal to 0.8 g/cm3. 
     
     
         15 . The cap according to  claim 13 , wherein said natural fibre-based material of the cup-shaped body ( 3 ) contains up to 10% synthetic polymers and/or up to 10% additives. 
     
     
         16 . The cap according to  claim 1 , wherein the cup-shaped body ( 3 ) is made of metal material. 
     
     
         17 . The cap according to  claim 1 , wherein the skirt ( 4 ) has an undulating profile defining an annular portion ( 7 ) in a ring configured to be plastically deformed on the mouth ( 2   a ) of the container ( 2 ). 
     
     
         18 . The cap according to  claim 1 , wherein the skirt ( 4 ) has a thread ( 8 ) made on the inner surface ( 4   a ) of the skirt ( 4 ) itself, said thread ( 8 ) being configured to screw the cup-shaped body ( 3 ) onto the mouth ( 2   a ) of the container ( 2 ). 
     
     
         19 . A method for making a cap for a container, comprising the steps of:
 preparing a cup-shaped body ( 3 ) having a skirt ( 4 ) which extends around an axis (X) and a transversal wall ( 5 ) positioned transversally to the axis (X);   preparing a gasket ( 10 ) inside a cavity ( 6 ) of the cup-shaped body interposed between an inner surface ( 4   a ) of the skirt ( 4 ) and an inner surface ( 5   a ) of the transversal wall ( 5 );   engaging said gasket ( 10 ) at least with the inner surface ( 5   a ) of the transversal wall ( 5 ); wherein said step of preparing a gasket ( 10 ) comprises the step of making the gasket ( 10 ) with a natural fibre-based material comprising at least 30% cellulose by weight, said gasket ( 10 ) having a modulus of compression of between 0.5 and 50 Mpa.   
     
     
         20 . The method according to  claim 19 , wherein said step of making the gasket ( 10 ) is performed by moulding starting from a flat sheet ( 17 ) of natural fibre-based material to define an annular peripheral portion ( 11 ) having an annular surface ( 13 ) for contact with the edge of a mouth ( 2   a ) of the container ( 2 ). 
     
     
         21 . The method according to  claim 20 , wherein it also comprises, before moulding of the flat sheet ( 17 ), a step of coupling a barrier layer ( 15 ) to said flat sheet ( 17 ); said barrier layer ( 15 ) being configured to be positioned towards the mouth ( 2   a ) of the container ( 2 ). 
     
     
         22 . The method according to  claim 19 , wherein said step of making the gasket ( 10 ) comprises the sub-step of moulding a natural fibre-based material which is a powder or a fluff or an airlaid directly on the inner surface ( 5   a ) of the transversal wall ( 5 ). 
     
     
         23 . The method according to  claim 19 , wherein the method also comprises the step of interposing an adhesive layer between the gasket ( 10 ) and the inner surface ( 5   a ) of the transversal wall ( 10 ) in order to secure the gasket ( 10 ) to said transversal wall ( 5 ). 
     
     
         24 . The method according to  claim 19 , wherein said cup-shaped body ( 3 ) is prepared using a natural fibre-based material comprising at least 30% cellulose by weight.