Integrally Blow-Moulded Bag-in-Container Having an Inner Layer and the Outer Layer Made of the Same Material and Preform for Making It

Abstract

The invention is an integrally blow-moulded bag-in-container and preform for making it. The bag-in-container has 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. The container further has at least one interface vent fluidly connecting the interface between inner and outer layers to the atmosphere, wherein the 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 coaxially with the bag-in-container's mouth. Processes for manufacturing a preform and a bag-in-container as defined above are defined too.

1 . An integrally blow-moulded bag-in-container comprising the same polymer in contact on either side of the interface between the inner and outer layers. 
     
     
         2 . The bag-in-container according to  claim 1  wherein the inner and outer layers comprise a semicrystalline material. 
     
     
         3 . The bag-in-container according to  claim 2 , 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. 
     
     
         4 . The bag-in-container according to  claim 1 , wherein it further comprises at least one vent 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. 
     
     
         5 . 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. 
     
     
         6 . A preform for blow-moulding a bag-in-container, comprising: an inner layer and an outer layer, wherein a preform forms a two layer container upon blow-moulding, and wherein the thus obtained inner layer of said container releases from the thus obtained outer layer upon introduction of a gas at at least one point of interface between the two layers, wherein the inner and outer layers are the same material. 
     
     
         7 . The preform according to  claim 6  wherein the inner and outer layers are of a semicrystalline material. 
     
     
         8 . The preform according to  claim 7 , 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. 
     
     
         9 . The preform according to  claim 6 , wherein the at least one point of interface is a vent 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. 
     
     
         10 . The preform according to  claim 6 , wherein more than one vent is distributed around the lip of the preform's mouth. 
     
     
         11 . The preform according to  claim 6 , wherein the inner and outer layers of the preform are connected by an interface throughout substantially the whole inner surface of the outer layer. 
     
     
         12 . The preform according to  claim 6 , 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. 
     
     
         13 . The preform according to  claim 6 , having an assembly of two separate inner and outer preforms fitted into one another. 
     
     
         14 . The preform according to  claim 6 , having an integral preform obtained by injection moulding one layer on top of the other.