Vessel and method of manufacture thereof

Abstract

The invention concerns a novel sample tube and a method of manufacturing a such a sample tube. According to the method an oversized mould cavity is formed with an opposing pair of mould members of an injection moulding machine, the mould members being movable relative to each other and between which mould members the sample tube is formed. A volume of resin exceeding the prescribed volume of the sample tube is injected into the cavity and force is applied to said mould members in order to reduce the volume of said mould cavity for displacing molten polymer in the cavity and for compressing the polymer to form said sample tube. By means of the invention, sample tubes and vessels having ultra thin walls can be manufactured.

1 . Vessel for thermal cycling applications, the vessel being made from a thermoplastic material and comprising at least one cavity capable of containing a sample, the walls of the cavity having a thin wall portion which has a consistent wall thickness of less than about 0.0065 inch (less than about 0.17 mm), wherein the thermoplastic material comprises polymeric resin, which has been hardened in pressurized condition, the pressurized condition being achieved at least partly by mechanical clamping of molten resin.  
     
     
         2 . The vessel according to  claim 1 , which comprises a plurality of wells arranged in a grid, each of the wells having a conical thin wall portion having a closed narrower end and an open wider end.  
     
     
         3 . The vessel according to  claim 1  or  2 , wherein the thermoplastic material is polypropylene.  
     
     
         4 . The vessel according to  claim 1 , which has a plurality of sample cavities arranged in one- or two-dimensional grid, each of the cavities having said thin wall portion.  
     
     
         5 . A method of manufacturing a sample tube having a predetermined volume and mass, said method being carried out by injection moulding in an injection moulding machine using a molten thermoplastic resin, the method comprising the steps of: 
 forming an oversized mould cavity with an opposing pair of mould members of said injection moulding machine, the mould members being movable relative to each other and between which mould members said sample tube is formed;    injecting into said oversized cavities a volume of resin exceeding the prescribed volume of the sample tube to be formed; and    applying force to said mould members to reduce the volume of said mould cavity for displacing molten polymer in the cavity and for compressing the polymer to form said sample tube.    
     
     
         6 . The method according to  claim 5 , which further comprises the step of cooling the polymer in compressed condition for preventing deformation of the sample tube.  
     
     
         7 . The method according to  claim 5  or  6 , wherein that the step of reducing the volume of the mould cavity comprises moving the mould members relative to each other such that the minimum distance between them is consistently less than 0.0065 inch (0165 mm) at some part of the cavity.  
     
     
         8 . The method according to  claim 5 , wherein the mould members comprise a core pin having the shape of the inner surface of the sample tube and its counterpart having the shape of the outer surface of the tube.  
     
     
         9 . The method according to  claim 8 , wherein the step of reducing the volume of the mould cavity comprises moving the core pin relative to the injection moulding machine and relative to said counterpart.  
     
     
         10 . The method according to  claim 5 , wherein the step of reducing the volume of the cavity comprises moving the mould members 0.5-0.2 inch (12.7 mm to 5.1 mm), typically 0.1-0.15 inch (2.54 mm to 3.81 mm) relative to each other.  
     
     
         11 . The method according to  claim 5 , wherein the sample tube is part of a vessel comprising a strip or array of essentially similar sample tubes such as a microtiter plate having a plurality of tubes arranged in a grid.  
     
     
         12 . A mould arrangement for manufacturing vessels for thermal cycling applications comprising at least one well having a wall using a mould comprising 
 a first mould member having core pins, which define the internal diameter and the internal shape of well, and    a second mould member defining the outer diameter and outer shape of the well,    wherein    the mould members are adapted movably relative to each other between two positions,    in the first position a volume of resin exceeding the prescribed volume of the sample tube to be formed can be injected between the mould members,    in the second position, the mould members are adapted to displace and compress the injected resin to form said vessel.    
     
     
         13 . A mould arrangement according to  claim 12 , wherein in the second position, the mould members form a mould cavity, which defines a thin wall portion for the well to be produced, the thin wall portion having a consistent wall thickness of less than about 0.0065 inch (less than about 0.17 mm).