Polymeric materials

Abstract

High pressure injection apparatus 2 for addition of a liquid formulation into a polymer melt stream at position 4 comprises pump assembly 6 upstream of an injector assembly 8 . Pump assembly 6 is arranged to increase the pressure of the liquid formulation to a high pressure (e.g. up to 400 bar) and to accurately meter the liquid formulation to the injector assembly 8 which is arranged to inject the liquid formulation into the polymer melt stream. The polymer melt may be spun, for example to produce Fully Drawn Yarn (FDY) or Partial Orientated Yarn (POY). The pump assembly 6 comprises a syringe pump 12 which comprises a tube 14 in which a piston 16 is slideably received and is arranged to urge liquid formulation 18 within the tube to an outlet 20 which is coupled to an inlet of injector assembly 8.

1 . Injection apparatus for injecting a fluid formulation into a molten polymeric material, the apparatus comprising:
 (a) a drive pump, said drive pump comprising a chamber for containing fluid formulation to be injected and a drive member, said drive member being linearly moveable within the chamber to drive fluid formulation downstream of the drive member to an outlet of the drive pump;   (b) an injector device downstream of the outlet of the drive pump and being arranged to inject fluid formulation received from said drive pump into molten polymeric material.   
     
     
         2 . Apparatus according to  claim 1 , wherein said drive pump is arranged to deliver fluid formulation at a pressure of at least 30 bar. 
     
     
         3 . Apparatus according to  claim 1 , wherein said chamber of said drive pump has a maximum volume arranged to contain fluid formulation of less than 500 ml, a minimum volume of at least 50 ml, and/or a diameter of at least 10 mm and/or a length of at least 10 cm and less than 50 cm. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . Apparatus according to  claim 1 , wherein said drive member has a contact face which is arranged to contact fluid formulation in use and drive it to said outlet of said drive pump wherein said contact face is substantially planar across its entire extent. 
     
     
         7 . Apparatus according to  claim 6 , wherein, when said drive member is in a second position defining a minimum volume of said chamber, said contact face contacts an outlet face of said chamber, wherein said outlet face includes an outlet via which fluid formulation can exit the chamber wherein, when in said second position, there is no gap defined between any planar part of said contact face and any planar part of said outlet face. 
     
     
         8 . Apparatus according to  claim 1 , wherein said drive member of said drive pump is operatively connected to a force applying device which is arranged to apply a force to the drive member to cause it to move within the chamber towards said outlet, wherein said force applying device is arranged to apply a linear force of at least 1000N to the drive member. 
     
     
         9 . Apparatus according to  claim 8 , wherein said force applying device includes a drive screw which is axially aligned with an elongate axis of the drive member, wherein a motor is provided to apply a linear force to the drive member, wherein a rotational axis of said motor, an elongate axis of said drive screw and said drive member are axially aligned. 
     
     
         10 . (canceled) 
     
     
         11 . Apparatus according to  claim 1 , wherein said injector device includes a valve which is arranged to be opened or closed for controlling passage of fluid formulation downstream of the device, wherein said valve is arranged to withstand a fluid pressure of at least 100 bar. 
     
     
         12 . (canceled) 
     
     
         13 . Apparatus according to  claim 1 , wherein said drive pump is releasably securable to said injector device. 
     
     
         14 . Apparatus according to  claim 1 , wherein said injection apparatus is provided in combination with polymer supply apparatus for supplying molten polymeric material. 
     
     
         15 . Apparatus according to  claim 10 , wherein said injection apparatus is provided in combination with a mixer arranged to mix fluid formulation injected from said injection device and molten polymeric material. 
     
     
         16 . Apparatus according to  claim 1 , wherein said apparatus is provided in combination with a polymeric material forming device in which polymeric material is formed into a solid product. 
     
     
         17 . Apparatus according to  claim 1 , wherein a processing unit is associated with said injection apparatus, wherein the unit is programmed so that an operator can set the rate of delivery of fluid formulation from said injection apparatus; and/or the unit is arranged to open and/or close a valve associated with said injection device for controlling passage of fluid formulation into molten polymer material; and/or the unit is arranged to receive information relating to the pressure of liquid formulation in the injection apparatus and/or the pressure of molten polymeric material associated with polymer supply apparatus. 
     
     
         18 . Apparatus according to  claim 1 , wherein a user-interface is associated with the injection apparatus, wherein said user interface communicates with said processing unit and wherein the apparatus is arranged for input of one or more of the following variables via said user interface:
 the rate of throughput of polymeric material in a polymer supply apparatus;   the identity and/or characteristics of the drive pump used;   the specific gravity of the fluid formulation to be injected; and   the desired addition rate of fluid formulation into the polymeric material.   
     
     
         19 . Apparatus according to  claim 1 , which includes a fluid formulation within said chamber and which includes a thermoplastic polymeric material in a polymer supply apparatus which is provided in combination with said injection apparatus. 
     
     
         20 . A method of injecting a fluid formulation into a molten polymeric material using the injection apparatus according to  claim 1 , the method comprising:
 (i) selecting an injection apparatus comprising a drive pump, said drive pump comprising a chamber containing fluid formulation to be injected and a drive member, said drive member being linearly moveable within the chamber to drive fluid formulation downstream of the drive member to an outlet of the drive pump;   (ii) operating the drive pump to drive fluid formulation towards molten polymeric material; and   (iii) injecting said fluid formulation into molten polymeric material.   
     
     
         21 . (canceled) 
     
     
         22 . A method according to  claim 20 , wherein said formulation includes 15 to 80 wt % of vehicle and 20 to 85 wt % of additives; and wherein in step (iii), fluid formulation is injected into molten polymeric material at a pressure of at least 30 bar; and wherein prior to step (iii), inputting the let-down-ratio (LDR) into a processing unit via a user interface; and inputting a desired dose rate, or information relating to a desired dose rate, at which the fluid formulation is to be dosed into the molten material; and wherein downstream of step (iii), polymeric material after contact with said fluid formulation is melt processed. 
     
     
         23 - 29 . (canceled) 
     
     
         30 . A method of selecting a colour formulation for manufacturing, in a selected colour, a sample wherein said sample comprises a polymeric material, the method comprises:
 (i) selection of a first trial colour formulation;   (ii) injecting said first trial colour formulation into a molten polymeric material using the injection apparatus of  claim 1 , said injection apparatus comprising a drive pump, said drive pump comprising a chamber for containing fluid formulation to be injected and a drive member, said drive member being linearly moveable within the chamber to drive fluid formulation downstream of the drive member to an outlet of the drive pump;   (iii) after said injection, producing said sample;   (iv) assessing said sample produced to determine if its colour is acceptable;   (v) optionally selecting one or more other trial colour formulations or selecting a different let-down-ratio (LDR) for injection into molten polymeric material and repeating steps (ii) to (iv) until it is determined that the colour of the sample is acceptable.   
     
     
         31 . Apparatus according to  claim 1 , wherein:
 a drive member of said drive pump is operatively connected to a force applying device which is arranged to apply a force to the drive member to cause it to move within the chamber towards said outlet, wherein said force applying device is arranged to apply a linear force of at least 1000N to the drive member;   said injector device including a valve which is arranged to be opened or closed for controlling passage of fluid formulation downstream of the device, wherein said valve is arranged to withstand a fluid pressure of at least 100 bar;   said drive pump is releasably securable to said injector device;   said injection apparatus is provided in combination with a melt-processing apparatus for supplying molten polymeric material; and   a processing unit is associated with said injection apparatus, wherein the unit is programmed so that an operator can set the rate of delivery of fluid formulation from said injection apparatus; and/or the unit is arranged to open and/or close a valve associated with said injection device for controlling passage of fluid formulation into molten polymer material; and/or the unit is arranged to receive information relating to the pressure of liquid formulation in the injection apparatus and/or the pressure of molten polymeric material associated with polymer supply apparatus.   
     
     
         32 . Apparatus according to  claim 1 , wherein:
 said drive pump is arranged to deliver fluid formulation at a pressure of at least 100 bar;   said chamber of said drive pump has a maximum volume arranged to contain fluid formulation of less than 500 ml;   said drive member has a contact face which is arranged to contact fluid formulation in use and drive it to said outlet of said drive pump wherein said contact face is substantially planar across its entire extent; and   when said drive member is in a second position defining a minimum volume of said chamber, said contact face contacts an outlet face of said chamber, wherein said outlet face includes an outlet via which fluid formulation can exit the chamber when in said second position, and wherein there is no gap defined between any planar part of said contact face and any planar part of said outlet face.