Process of Injection Compression Moulding of Water-Soluble Polymer and Container From Water-Soluble Polymer

Abstract

A method of injection moulding an article from a water-soluble polymer, said method comprising: providing a mould comprising a male portion and a female portion defining a mould cavity, said portions being movable relative to one another to vary the volume of the mould cavity, injecting molten water-soluble polymer into the mould when the male portion and female portion are in a first position, and initiating relative movement of the male portion and female portion to reduce the volume of the mould cavity so as to force the molten water-soluble polymer already in the mould cavity into at least part of the remainder of the mould.

1 . A method of injection moulding an article from a water-soluble polymer, said method comprising:
 providing a mould comprising a male portion and a female portion defining a mould cavity, said portions being movable relative to one another to vary the volume of the mould cavity,   injecting molten water-soluble polymer into the mould when the male portion and female portion are in a first position, and   initiating relative movement of the male portion and female portion to reduce the volume of the mould cavity so as to force the molten water-soluble polymer already in the mould cavity into at least part of the remainder of the mould.   
   
   
       2 . A method according to  claim 1 , wherein the water-soluble polymer is a poly(vinyl alcohol) and/or a cellulose ether. 
   
   
       3 . A method according to  claim 1 , wherein the injection step is completed before the male portion and female portion are moved relative to one another to reduce the volume of the mould. 
   
   
       4 . A method according to  claim 1 , wherein the injection step is carried out at a pressure of 50 to 2000 psi. 
   
   
       5 . A method according to  claim 1 , wherein the article is a container. 
   
   
       6 . A method according to  claim 5 , wherein the container comprises two or more compartments. 
   
   
       7 . A method according to  claim 5 , which further comprises the step of:
 introducing a washing, fabric care, dishwashing, water-softening, laundry, rinse aid, anti-bacterial, anti-septic composition and/or a refill composition for a trigger-type spray into the moulded container, and sealing the container.   
   
   
       8 . A method according to  claim 5 , wherein the container is sealed by a water-soluble closure part. 
   
   
       9 . A method according to  claim 8 , wherein the water-soluble closure part comprises a poly(vinyl alcohol) and/or a cellulose ether. 
   
   
       10 . A method according to  claim 1 , wherein further molten polymer is introduced into the mould once the male portion and female portion have been moved relative to one another to reduce the volume of the mould. 
   
   
       11 . A method of ware washing comprising the step of:
 introducing a container formed by the method according to  claim 1  into a ware washing machine.   
   
   
       12 . A container formed from a water-soluble polymer, said container comprising a receptacle part having a base portion and at least one side wall portion, wherein the base portion has a mean thickness of 50 to 2000 microns and the thickness of the thinnest part of the base is at least 90% of the thickness of the thickest part of the base portion. 
   
   
       13 . A container according to  claim 12 , which further comprises a water-soluble closure part that is sealingly joined to the receptacle part. 
   
   
       14 . A container according to  claim 12 , which contains a washing, fabric care, dishwashing, water-softening, laundry, rinse aid, anti-bacterial, anti-septic composition and/or a refill composition for a trigger-type spray. 
   
   
       15 . A container according to  claim 14 , wherein the composition has a mass of 15 to 40 g. 
   
   
       16 . A container according to  claim 12 , wherein the water-soluble polymer comprises a poly(vinyl alcohol) and/or a cellulose ether. 
   
   
       17 . A container according to  claim 12 , which is an injection moulded container. 
   
   
       18 . A container according to  claim 12 , wherein the base portion has a mean thickness that is less than the mean thickness of the side wall(s).