Multilayer cap liner, container cap or neck comprising same, and methods for making same

Abstract

The invention concerns a cap liner ( 9 ) comprising: a middle layer made of a plastic material with gas barrier effect; first and second outer layers comprising each a polyolefin resin and arranged on either side of the middle layer; an intermediate polyethylene layer, placed between the middle layer and each of the outer layers, the intermediate layers being designed to protect the middle layer against moisture and to prevent degradation of said middle layer gas barrier properties. The cap liner can be placed in a cap near its transverse wall or towards the free end of its skirt or on a container neck. It can be planar or thermoformed. The invention also concerns methods for producing a neck-joint cap assembly.

1 . A composite seal able to be placed on a neck ( 24 ) of a receptacle ( 25 ) or in a stopper ( 10 ) comprising an annular skirt ( 13 ) provided with an internal thread ( 15 ) intended to cooperate with the external thread ( 30 ) of a neck ( 24 ) of a receptacle ( 25 ) for mounting the stopper ( 10 ) by screwing on the said neck ( 24 ), the said seal ( 9 ) comprising firstly a middle layer ( 2 ) produced from a plastics material with a gas barrier effect and secondly first and second external layers ( 7 ,  8 ) each comprising a polyolefin resin and disposed on each side of the said middle layer ( 2 ), the said seal also comprising, between the middle layer ( 2 ) and each of the external layers ( 7 ,  8 ), an intermediate polyethylene layer ( 3 ,  4 ), the said intermediate layers ( 3 ,  4 ) being intended to protect the middle layer ( 2 ) from moisture and thus to prevent degradation of the gas barrier properties of the said middle layer ( 2 ), characterized in that the middle layer ( 2 ) has a thickness of between 35 and 65 μm.  
     
     
         2 . A seal according to  claim 1 , characterised in that the intermediate layers ( 3 ,  4 ) are produced from low or medium density polyethylene.  
     
     
         3 . A seal according to  claim 1 , characterised in that the intermediate layers ( 3 ,  4 ) have a thickness of between 80 and 150 μm and in particular, around 115 μm.  
     
     
         4 . A seal according to  claim 1 , characterised in that the intermediate layers ( 3 ,  4 ) are connected to the middle layer ( 2 ) by a layer of adhesive ( 5 ,  6 ).  
     
     
         5 . A seal according to  claim 1 , characterised in that the polyethylene making up the intermediate layers ( 3 ,  4 ) has a rigidity modulus of between 250 and 500 MPa.  
     
     
         6 . A seal according to  claim 1 , characterised in that the middle layer ( 2 ) consists of a sheet of EVOH (ethyl vinyl alcohol copolymer).  
     
     
         7 . A seal according to  claim 1 , characterised in that the material making up the middle layer ( 2 ) has a rigidity modulus of between 1500 and 2500 MPa.  
     
     
         8 . A seal according to  claim 1 , characterised in that the materials making up the external layers ( 7 ,  8 ) have a rigidity modulus of between 50 and 100 MPa.  
     
     
         9 . A seal according to  claim 1 , characterised in that the first external layer ( 7 ) is produced from EVA (ethylene and vinyl acetate copolymer) comprising between 7% and 15% VA (vinyl acetate).  
     
     
         10 . A seal according to  claim 1 , characterised in that the first external layer ( 7 ) has a thickness of between 90 and 160 μm.  
     
     
         11 . A seal according to  claim 1 , characterised in that the second external layer ( 8 ) comprises polyethylene or EVA (ethylene and vinyl acetate copolymer).  
     
     
         12 . A seal according to  claim 1 , characterised in that the second external layer ( 8 ) comprises a compound with an oxygen-absorbing effect.  
     
     
         13 . A seal according to  claim 12 , characterised in that the compound with an oxygen-absorbing effect comprises sodium ascorbate and/or sodium sulphite.  
     
     
         14 . A seal according to  claim 1 , characterised in that the second external layer ( 8 ) has a thickness of between 130 and 230 μm.  
     
     
         15 . A stopper comprising firstly a transverse end wall ( 12 ) and secondly an annular skirt ( 13 ) projecting substantially perpendicular to the said transverse wall ( 12 ) and comprising an internal thread ( 15 ) intended to cooperate with the external thread ( 30 ) on a neck ( 24 ) of a receptacle ( 25 ) for mounting the stopper ( 10 ) by screwing on the said neck ( 24 ), characterised in that it also comprises a substantially discoid seal ( 9 ) according to any one of  claims 1  to  14 , the said seal ( 9 ) being placed inside the stopper ( 10 ), substantially perpendicular to the axis ( 11 ) of the said stopper ( 10 ), and being intended to provide impermeability to liquids and impermeability to gases between the inside and outside of the receptacle ( 25 ) closed by the said stopper ( 10 ).  
     
     
         16 . A stopper according to  claim 15 , characterised in that the seal ( 9 ) is placed inside the stopper ( 10 ) so that the first external layer ( 7 ) is situated opposite the transverse end wall ( 12 ).  
     
     
         17 . A stopper according to  claim 15 , characterised in that the seal ( 9 ) is substantially flat.  
     
     
         18 . A stopper according to  claim 15 , characterised in that the seal ( 9 ) is situated close to the transverse wall ( 12 ).  
     
     
         19 . A stopper according to  claim 15 , characterised in that it also comprises at least one serration ( 21 ) projecting radially from the annular skirt ( 13 ) towards the axis ( 11 ) of the stopper ( 10 ), the said serration ( 21 ) being situated close to the end part ( 22 ) of the skirt ( 13 ) connected to the transverse wall ( 12 ) of the stopper ( 10 ) so that the seal ( 9 ) can be placed between the said serration ( 21 ) and the transverse wall ( 12 ), the said serration ( 21 ) being intended to hold the seal ( 9 ) at the bottom of the stopper ( 10 ).  
     
     
         20 . A stopper according to  claim 15 , characterised in that the seal ( 9 ) is thermoformed, so that it has a shape complementary firstly to that of the neck ( 24 ) of the receptacle ( 25 ) with which the stopper ( 10 ) is intended to be associated and secondly that of the internal face ( 38 ) of the transverse end wall ( 12 ) of the stopper ( 10 ), the said seal ( 9 ) being situated, before the stopper ( 10 ) is fitted on the neck ( 24 ) of the receptacle ( 25 ), close to the free end part ( 19 ) of the skirt ( 13 ) opposite to the transverse wall ( 12 ).  
     
     
         21 . A stopper according to  claim 19 , characterised in that it also comprises a tamper-evident band ( 18 ) comprising means ( 18   a ,  18   b ,  37 ) of holding the seal ( 9 ) close to the said tamper-evident band ( 18 ) before the stopper ( 10 ) is fitted on the neck ( 24 ) of the receptacle ( 25 ).  
     
     
         22 . A stopper according to  claim 20 , characterised in that it comprises a substantially annular lip ( 33 ) projecting from the transverse wall ( 12 ) in the same direction as the skirt ( 13 ), the said lip ( 33 ) being intended to cooperate with the internal face ( 34 ) of the neck ( 24 ) of the receptacle ( 25 ), the seal ( 9 ) being thermoformed so as to have a recess ( 40 ) forming a housing ( 42 ) able to receive the said lip ( 33 ).  
     
     
         23 . A stopper according to  claim 20 , characterised in that, after the stopper ( 10 ) is fitted on the neck ( 24 ) of the receptacle ( 25 ), the seal ( 9 ) is situated close to the transverse wall ( 12 ).  
     
     
         24 . A stopper according to  claim 23 , further characterised in that it comprises a lug ( 36 ) projecting substantially radially from the annular skirt ( 13 ) towards the axis ( 11 ) of the stopper ( 11 ), the said lug ( 36 ) being situated close to the end part ( 22 ) of the skirt ( 13 ) connected to the transverse wall ( 12 ) of the stopper ( 10 ) and in that the lip ( 33 ) is slightly divergent towards the outside in a truncated cone from its base in the direction of its free end ( 35 ), so that, after the stopper ( 10 ) is fitted on the neck ( 24 ) of the receptacle ( 25 ), the seal ( 9 ) is placed between the transverse wall ( 12 ) of the stopper ( 10 ) and the lug ( 36 ), the divergence of the lip ( 33 ) providing the holding of the seal ( 9 ) at the bottom of the stopper ( 10 ).  
     
     
         25 . A receptacle neck or a receptacle having a neck, the said neck ( 24 ) being provided with an external thread ( 30 ) intended to cooperate with the internal thread ( 15 ) on a stopper ( 10 ) for mounting the stopper ( 10 ) by screwing onto the said neck ( 24 ), characterised in that it also comprises a substantially discoid seal ( 9 ), said seal ( 9 ) covering the opening ( 28 ) of the neck ( 24 ) and being thermoformed so that it has a shape complementary firstly to that of the neck ( 24 ) of the receptacle and secondly to that of the internal face ( 38 ) of the transverse end wall ( 12 ) of the stopper ( 10 ) intended to be associated with the neck ( 24 ), the said receptacle ( 25 ) being empty or at least partially filled with a certain content.  
     
     
         26 . A receptacle neck or a receptacle having a neck according to  claim 25 , characterised in that the seal ( 9 ) is placed on the neck ( 24 ) so that the second external layer ( 8 ) is situated facing the inside of the neck ( 24 ).  
     
     
         27 . An assembly comprising a stopper ( 10 ) according to  claim 15 , further comprising a neck ( 24 ) of a receptacle ( 25 ) or a receptacle ( 25 ) having a neck ( 24 ), the said receptacle ( 25 ) being empty or at least partially filled with a certain content.  
     
     
         28 . An assembly according to  claim 27 , further characterised in that, when the stopper ( 10 ) is screwed onto the neck ( 24 ), an area of the seal ( 9 ) is compressed between the annular lip ( 33 ) and the internal face ( 34 ) of the neck ( 24 ) of the receptacle ( 25 ).  
     
     
         29 . An assembly comprising a stopper and a receptacle neck ( 24 ), a receptacle neck or a receptacle having a neck, the said neck ( 24 ) being provided with an external thread ( 30 ) intended to cooperate with the internal thread ( 15 ) on a stopper ( 10 ) for mounting the stopper ( 10 ) by screwing onto the said neck ( 24 ), characterised in that it also comprises a substantially discoid seal ( 9 ), said seal ( 9 ) covering the opening ( 28 ) of the neck ( 24 ) and being thermoformed so that it has a shape complementary firstly to that of the neck ( 24 ) of the receptacle and secondly to that of the internal face ( 38 ) of the transverse end wall ( 12 ) of the stopper ( 10 ) intended to be associated with the neck ( 24 ), the said receptacle ( 25 ) being empty or at least partially filled with a certain content.  
     
     
         30 . An assembly according to  claim 27 , further characterised in that, when the stopper ( 10 ) is screwed onto the neck ( 24 ), the seal ( 9 ) is compressed, close to its peripheral area ( 32 ), between the rim ( 27 ) of the neck ( 24 ) of the receptacle ( 25 ) and the transverse end wall ( 12 ) of the stopper ( 10 ), so as to ensure liquidtightness and impermeability to gases between the inside and outside of the receptacle ( 25 ).  
     
     
         31 . A method of corking a neck ( 24 ) of a receptacle ( 25 ) or a receptacle ( 25 ) having a neck ( 24 ) with a stopper ( 10 ), according to  claim 20 , characterised in that, when an axial and/or helical screwing movement is imparted to the stopper ( 10 ), so that the thread ( 15 ) on the stopper ( 10 ) and the thread ( 30 ) on the neck ( 24 ) come into mutual engagement, the seal ( 9 ) is moved by the rim ( 27 ) of the neck ( 24 ) axially towards the transverse wall ( 12 ) of the stopper ( 10 ) until it comes substantially into contact with the said transverse wall ( 12 ).  
     
     
         32 . A method of producing a receptacle neck, or a receptacle having a neck, provided with a seal, in accordance with  claim 25 , characterised in that a previously thermoformed seal ( 9 ) is placed on the said neck ( 24 ), the said seal ( 9 ) covering the opening ( 28 ) in the neck ( 24 ).  
     
     
         33 . A method of producing a receptacle neck, or a receptacle having a neck, provided with a seal, in accordance with  claim 25 , characterised in that it comprises the following steps: 
 a substantially discoid and flat seal ( 9 ) is placed on the neck ( 24 ), the said seal ( 9 ) covering the opening ( 28 ) in the said neck ( 24 );    the seal ( 9 ) is fashioned by thermoforming so as to give it a shape complementary firstly to that of the neck ( 24 ) and secondly to that of the internal face ( 38 ) of the transverse end wall ( 12 ) of the stopper ( 10 ) intended to be associated with the neck ( 24 ).    
     
     
         34 . A method of corking a neck ( 24 ) of a receptacle ( 25 ) or a receptacle ( 25 ) having a neck ( 24 ) according to  claim 25 , further characterised by placing a stopper on the said neck ( 24 ) provided with the thermoformed seal ( 9 ).