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 present invention relates to an integrally blow-moulded bag-in-container having an integrally blow-moulded bag-in-container wherein the same polymer is in contact on either side of the interface between the inner and outer layers. It also concerns a preform for blow-moulding a bag-in-container, having an inner layer and an outer layer, wherein the preform forms a two-layer container upon blow-moulding, and wherein the thus obtained inner layer of the container releases from the thus obtained outer layer upon introduction of a gas at a point of interface between the two layers. The inner and outer layers are the same material.

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 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.