Infusion packets and a process for their manufacture

Abstract

The present invention relates to a process for the manufacture of infusion packets, the process comprising: • (a) providing a first sheet of thermoplastic material (2) which is porous or non- porous; • (b) thermoforming portions of the first sheet into a three-dimensional shape; • (c) providing a second sheet of material; • (d) dosing an infusible substance into the thermoformed portions of the first sheet or onto the second sheet; • (e) sealing the first and second sheets together to form pockets containing the infusible substance such that each pocket includes at least one thermoformed portion of the first sheet; • (f) severing the pockets at the seals to form infusion packets each having a chamber containing the infusible substance,

1 . A process for the manufacture of infusion packets, the process comprising:
 (a) providing a first sheet of thermoplastic material which is porous or non-porous;   (b) thermoforming portions of the first sheet into a three-dimensional shape;   (c) providing a second sheet of material;   (d) dosing an infusible substance into the thermoformed portions of the first sheet or onto the second sheet;   (e) sealing the first and second sheets together to form pockets containing the infusible substance such that each pocket includes at least one thermoformed portion of the first sheet;   (f) severing the pockets at the seals to form infusion packets each having a chamber containing the infusible substance,   
       wherein the first sheet is a polymer film with at least one embossed surface, and 
       wherein the thermoformed portions of the first sheet are porous. 
     
     
         2 . A process as claimed in  claim 1  wherein the second sheet is a sheet of thermoplastic material. 
     
     
         3 . A process as claimed in  claim 2  wherein portions of the second sheet are thermoformed into a three-dimensional shape. 
     
     
         4 . A process as claimed in  claim 3  wherein the second sheet is a polymer film with at least one embossed surface. 
     
     
         5 . A process as claimed in  claim 3  wherein each pocket includes a thermoformed portion of the first sheet and a thermoformed portion of the second sheet. 
     
     
         6 . A process as claimed in  claim 1  wherein at least one of the embossed polymer films is made porous prior to thermoforming by simultaneous or sequential stressing of the embossed film in two directions in the plane of the film. 
     
     
         7 . A process as claimed in  claim 1  wherein the first and/or the second polymer m comprises polyethylene, preferably high-density polyethylene. 
     
     
         8 . A process as claimed in  claim 1  wherein the at least one embossed surface of the first and/or the second polymer film has a regular pattern of bosses. 
     
     
         9 . A process as claimed in  claim 1  wherein prior to thermoforming the at least one embossed surface of the first and/or the second polymer film has at least 60 features per 25 mm, preferably at least 80 features per 25 mm. 
     
     
         10 . A process as claimed in  claim 1  wherein the three-dimensional shape is a hemispherical shape. 
     
     
         11 . A process as claimed in  claim 1  wherein each sheet of thermoplastic material has an average thickness of less than 1.0 mm, preferably of less than 0.5 mm. 
     
     
         12 . A process as claimed in  claim 1  wherein thermoforming comprises the steps of bringing portions of the sheet of thermoplastic material at a temperature below that required for thermoforming into contact with a mould at a temperature above that of the thermoforming temperature of the thermoplastic material, pressing the mould into contact with the thermoplastic material, the contact between mould and thermoplastic material causing heat to transfer from the mould to the thermoplastic material and raising the thermoplastic material to a thermoformable temperature; such pressing causing thermoforming of the thermoplastic material to conform to the shape of the mould. 
     
     
         13 . A process as claimed in  claim 12  wherein the temperature of the mould is at least 60° C., more preferably at least 70° C. 
     
     
         14 . An infusion packet comprising a chamber that contains an infusible substance, wherein the packet comprises material that has been formed into a three-dimensional shape by thermoforming a thermoplastic polymer film having at least one embossed surface such that the thermoformed thermoplastic polymer film is porous, and a second sheet sealed with the first sheet to form the chamber. 
     
     
         15 . An infusion packet as claimed in  claim 14  wherein the thermoplastic polymer film comprises polyethylene, preferably high-density polyethylene.