Integrally blow-moulded bag-in-container having interface vents opening to the atmosphere at location adjacent to bag's mouth; preform for making it; and processes for producing the preform and bag-in-container

Abstract

The invention is an integrally blow-moulded bag-in-container ( 2 ) and preform ( 1 ) for making it The bag-in-container ( 2 ) has an inner layer ( 21 ) forming the bag and an outer layer ( 22 ) forming the container, and a mouth ( 5 ) fluidly connecting the volume defined by the bag to the atmosphere. The container further has at least one interface vent ( 3 ) fluidly connecting the interface ( 14 ) between inner and outer layers to the atmosphere, wherein the at least one vent ( 3 ) runs parallel to the interface between inner and outer layers ( 21 ) ( 22 ) and opens to the atmosphere at a location ( 4 ) adjacent to, and oriented coaxially with the bag-in-container's mouth ( 5 ). Processes for manufacturing a preform and a bag-in-container as defined above are defined too.

1 . An integrally blow-moulded bag-in-container ( 2 ) comprising:
 an inner layer forming the bag and an outer layer forming the container, and a mouth fluidly connecting the volume defined by the bag to the atmosphere, said container having at least one interface vent fluidly connecting the interface between inner and outer layers to the atmosphere.   said at least one vent runs parallel to the interface between inner and outer layers and opens to the atmosphere at a location adjacent to, and oriented approximately coaxially with said bag-in-container's mouth.   
   
   
       2 . The bag-in-container according to  claim 1 , wherein the inner and outer layers are of different materials. 
   
   
       3 . The bag-in-container according to  claim 1 , wherein the inner and outer layers are of the same material. 
   
   
       4 . The bag-in-container according to  claim 1 , wherein the inner and outer layer consist of a material selected from PET, PEN, PTT, PA, PP, PE, HDPE, EVOH, PGAc, PLA, and copolymers or blends thereof. 
   
   
       5 . The bag-in-container according to  claim 1 , wherein the at least one vent is in the shape of a wedge with the broad side at the level of the opening ( 4 ) thereof and getting thinner as it penetrates deeper into the vessel, until the inner and outer layers meet to form an interface. 
   
   
       6 . The bag-in-container according to  claim 1 , wherein more than one vent is distributed around the lip of the bag-in-container's mouth. 
   
   
       7 . A preform for blow-moulding a bag-in-container according to  claim 1 , wherein said preform includes an inner layer and an outer layer, and a body, a neck region, and a mouth fluidly connecting the space defined by said inner layer to the atmosphere, wherein said inner and outer layers are connected to one another by an interface at least at the level of the neck region,
 said preform includes at least one interface vent running parallel to said interface and opening to the atmosphere at a location adjacent to, and oriented coaxially with said preform's mouth.   
   
   
       8 . The preform according to  claim 7 , wherein the inner and outer layers consist of different materials. 
   
   
       9 . The preform according to  claim 7 , wherein the inner and outer layers consist of the same material. 
   
   
       10 . The preform according to  claim 7 , wherein the inner and outer layers consist of a material selected from PET, PEN, PTT, PA, PP, PE, HDPE, EVOH, PGAc, PLA, and copolymers or blends thereof. 
   
   
       11 . The preform according to  claim 7 , wherein the at least one vent is in the shape of a wedge with the broad side at the level of the opening thereof and getting thinner as it penetrates deeper into the vessel, until the inner and outer layers meet to form an interface. 
   
   
       12 . The preform according to  claim 7 , wherein more than one vent is distributed around the lip of the preform's mouth. 
   
   
       13 . The preform according to  claim 7 , wherein the inner and outer layers of the preform are connected by an interface throughout substantially the whole inner surface of the outer layer. 
   
   
       14 . The preform according to  claim 7 , wherein the inner and outer layers of the preform are separated over a substantial area of the preform's body by a gap containing air and which is in fluid communication with at least one interface vent. 
   
   
       15 . The preform according to  claim 7 , having an assembly of two separate inner and outer preforms fitted into one another. 
   
   
       16 . The preform according to  claim 7 , having an integral preform obtained by injection moulding one layer on top of the other. 
   
   
       17 . A method for producing a bag-in-container having
 an inner layer forming the bag and an outer layer forming the container, and a mouth fluidly connecting the volume defined by the bag to the atmosphere, said container having at least one interface vent fluidly connecting the interface between inner and outer layers to the atmosphere,   said at least one vent runs parallel to the interface between inner and outer layers and opens to the atmosphere at a location adjacent to, and oriented approximately coaxially with said bag-in-container's mouth,   comprising the following steps:
 providing a preform having an integral preform obtained by injection moulding one layer on top of the other; 
 bringing said preform to blow-moulding temperature; 
 fixing the heated preform at the level of the neck region with fixing means in the blow-moulding tool; and 
 blow-moulding the heated preform to form a bag-in-container. 
   
   
   
       18 . The method according to  claim 17  wherein the preform consists of an assembly of two separate inner and outer preforms fitted into one another. 
   
   
       19 . The method according to  claim 17 , wherein the inner and outer layers of the preform are separated over a substantial area of the preform's body by a gap containing air and which is in fluid communication with at least one interface vent, and wherein the blow-moulding operation further comprises the following two stages:
 feeding a gas in a first stage into the space defined by the inner layer to stretch the preform, whilst the air in the gap separating the preform inner and outer layers is prevented from being evacuated by closing said at least one preform interface vent with a valve located in said fixing means; and   opening said valve in a second stage, when the air pressure building up in said gap reaches a preset value, thus allowing evacuation of the air enclosed in the gap.   
   
   
       20 . A method for manufacturing a preform, having an integral preform obtained by injection moulding one layer on top of the other, comprising the following steps:
 injection moulding the preform's inner layer onto a core;   injection moulding the preform's outer layer onto the inner layer; and
 extracting the thus formed preform from the core; 
   
     wherein said core is provided at the base thereof with at least one pin suitable for forming an interface vent running parallel to the interface between said first and second layers and opening to the atmosphere at a location adjacent to, and oriented approximately coaxially with the preform's mouth. 
   
   
       21 . The method according to  claim 20 , wherein the at least one pin is in the shape of a wedge with the broad side at the level of where it is connected to the core's base. 
   
   
       22 . The method according to  claim 20 , wherein more than one pin is distributed around the core.