Integrally blow-moulded bag-in-container comprising an inner layer and an outer layer comprising energy absorbing additives, and preform for making it

Abstract

The present invention relates to an integrally blow-moulded bag-in-container and preform for blow-moulding the bag-in-container. An inner layer and an outer layer are used, wherein the preform forms a two-layer container upon blow-moulding, and wherein the obtained inner layer of said container releases from the thus obtained outer layer upon introduction of a gas at a point of interface between the two layers. At least one of the inner and outer layers includes at least one additive allowing both inner and outer layers to reach their respective blow-moulding temperatures substantially simultaneously.

1 . A preform for blow-moulding a bag-in-container, comprising:
 an inner layer and an outer layer, wherein said preform forms a two layer container upon blow-moulding, and wherein the obtained inner layer of said container releases from the obtained outer layer upon introduction of a gas at a point of interface between said two layers; and   at least one of said inner and outer layers includes at least one additive allowing both inner and outer layers to reach their respective blow-moulding temperatures substantially simultaneously upon heating them together in a single oven.   
   
   
       2 . The preform according to  claim 1 , wherein the at least one additive is selected from the group of energy absorbing additives and colorants. 
   
   
       3 . The preform according to  claim 2 , wherein the energy absorbing additive is a member being selected from the group consisting of carbon black, graphite, diamond dust, diazonium salts, sulphonium salts, sulfoxonium salts, and iodonium salts. 
   
   
       4 . The preform according to  claim 1 , wherein the inner and outer layers consist of a different materials each selected from PET, PEN, PTT, PA, PP, PE, HDPE, EVOH, PGAc, PLA, and copolymers or blends thereof. 
   
   
       5 . The preform according to  claim 1 , 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. 
   
   
       6 . The preform according to  claim 1 , wherein more than one vent is distributed around the lip of the preform's mouth. 
   
   
       7 . The preform according to  claim 1 , wherein the inner and outer layers of the preform are connected by an interface throughout substantially the whole inner surface of the outer layer. 
   
   
       8 . The preform according to  claim 1 , 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. 
   
   
       9 . The preform according to  claim 1 , consisting of an assembly of two separate inner and outer preforms fitted into one another. 
   
   
       10 . The preform according to  claim 1 , including an integral preform obtained by injection moulding one layer on top of the other. 
   
   
       11 . A process for producing a bag-in-container comprising the following steps:
 providing a polymer preform having   an inner layer and an outer layer, wherein said preform forms a two layer container upon blow-moulding, and wherein the obtained inner layer of said container releases from the obtained outer layer upon introduction of a gas at a point of interface between said two layers; and   at least one of said inner and outer layers includes at least one additive allowing both inner and outer layers to reach their respective blow-moulding temperatures substantially simultaneously upon heating them together in a single oven   heating said preform to blow-moulding temperature in a single oven; and   blow-moulding the thus heated preform to form a bag-in-container;   
     wherein the type and amount of additives in at least one of the inner and outer layers of said preform are such that said two layers reach their respective blow-moulding temperatures substantially simultaneously. 
   
   
       12 . The process according to  claim 11 , wherein the at least one additive is selected from the group of energy absorbing additives and colorants. 
   
   
       13 . The process according to  claim 12 , wherein the energy absorbing additive is a ember being selected from the group of consistently carbon black, graphite, diamond dust, diazonium salts, sulphonium salts, sulfoxonium salts, and iodonium salts. 
   
   
       14 . The process according to  claim 11 , wherein the inner and outer layers include the same or different materials each selected from PET, PEN, PTT, PA, PP, PE, HDPE, EVOH, PGAc, PLA, and copolymers or blends thereof. 
   
   
       15 . The process according to  claim 11 , wherein the oven comprises infrared lamps. 
   
   
       16 . A bag-in-container made by the process comprising:
 providing a polymer preform having   an inner layer and an outer layer, wherein said preform forms a two layer container upon blow-moulding, and wherein the obtained inner layer of said container releases from the obtained outer layer upon introduction of a gas at a point of interface between said two layers; and   at least one of said inner and outer layers includes at least one additive allowing both inner and outer layers to reach their respective blow-moulding temperatures substantially simultaneously upon heating them together in a single oven   heating said preform to blow-moulding temperature in a single oven; and   blow-moulding the thus heated preform to form a bag-in-container;   
     wherein the type and amount of additives in at least one of the inner and outer layers of said preform are such that said two layers reach their respective blow-moulding temperatures substantially simultaneously. 
   
   
       17 . A process comprising using energy absorbing additives or colorants for the substantially simultaneous heating to the respective blow-moulding temperatures of the inner and outer layers of a preform for blow-moulding a bag-in-container.