Process for the production of water and solvent-free polymers

Abstract

The present invention relates to water and solvent-free polymers, in particular water and solvent-free synthetic rubber products like non-halogenated and halogenated butyl rubber products as well as a process for the production thereof. The invention further relates to a device suitable to accomplish said process.

1 . A process of removing volatile compounds from a concentrated fluid (L) containing at least one non-volatile polymer and at least one volatile compound which comprises at least the step of:
 a) feeding a concentrated fluid into at least one drying unit, the drying unit comprising in flow direction at least
 I) a first drying section ( 8 ) and 
 II) a main extruder section ( 9 ) comprising at least an
 extruder degassing section comprising at least a conveying section and a vent port with one or more vapor lines, 
 an accumulating section and an outlet section, 
 whereby volatile compounds are removed through the vent ports and vapor lines; 
 
   whereby
 the first drying section is either a kneader or a first extruder and the main extruder section is a main extruder or 
 the drying section and the main extruder section are both part of a main extruder, whereby the drying section is upstream the main extruder section and has a smaller cross section than the main extruder section and 
 the product obtained at the outlet section of the main extruder is substantially free of volatile compounds. 
   
     
     
         2 . The process pursuant to  claim 1 , characterized in that the non-volatile polymers are synthetic rubber products. 
     
     
         3 . The process pursuant to  claim 2 , characterized in that the synthetic rubber product are halogenated butyl rubbers. 
     
     
         4 . The process pursuant to  claims 1  to  3 , characterized in that the Fluid (F) contains from 3 to 50 wt % of a non-volatile polymer and from 60 to 97 wt % volatile compounds, whereby the aforementioned components add up to 90 to 100 of the total mass of fluid (F). 
     
     
         5 . The process pursuant to  claims 1  to  4 , characterized in that the first drying section is a first extruder and the main extruder section is a main extruder. 
     
     
         6 . The process pursuant to  claims 1  to  5 , characterized in that the drying section and the main extruder section are both part of a main extruder, whereby the drying section is upstream the main extruder section and has a smaller cross section than the main extruder section. 
     
     
         7 . The process pursuant to  claim 5 , characterized in that the main extruder has a larger cross sectional area than the first extruder. 
     
     
         8 . The process pursuant to  claims 1  to  7 , characterized in that the vent ports ( 15 ) are designed to prevent the material from coming out of the vent ports. 
     
     
         9 . The process pursuant to  claim 5 , characterized in that the vent ports ( 15 ) are equipped with stuffer screws. 
     
     
         10 . The process pursuant to  claims 5  to  9 , characterized in that the main extruder is operated in such a manner that the dimensionless throughput V/(n*d 3 ) is adjusted to from 0.01 to 0.7. 
     
     
         11 . The process pursuant to  claims 1  to  10 , characterized in that stripping agents are used. 
     
     
         12 . The process pursuant to  claims 1  to  11 , characterized in that the outlet section comprises an underwater processing device. 
     
     
         13 . The process pursuant to  claims 1  to  12 , characterized in that the fluid L is prepared by a process comprising at least the steps of
 A) treating a fluid in at least one concentrator unit comprising at least a heater, a degassing vessel and a vapor line, whereby the fluid is heated, the heated fluid is fed into a degassing vessel where part of the volatile compounds are removed via the vapor line to obtain a concentrated fluid, 
 B) reheating the concentrated fluid from step A) in at least one reheating unit to obtain a concentrated fluid L. 
 
     
     
         14 . The process pursuant to  claims 1  to  13 , characterized in that the fluid A or the fluid L is prepared by a process comprising at least the step of
 pre A) treating a crude fluid (A) in at least one pre-washing unit comprising at least a separating apparatus ( 26 ), whereby the fluid (A) is mixed with water to obtain an organic phase ( 28 ) comprising primarily non-volatile polymer and volatile organic compounds and an aqueous phase ( 27 ) comprising primarily water and hydrophilic compounds, and whereby the organic phase ( 28 ) is separated from the aqueous phase ( 27 ) in a separating apparatus ( 26 ) and further used as fluid (F) or directly as concentrated fluid L and whereby at least a part of the aqueous phase ( 27 ) is removed from the separating apparatus (fluid C). 
 
     
     
         15 . The process pursuant to  claims 1  to  14 , characterized in that fluid A is prepared by a process comprising at least the step of
 I) providing a reaction medium comprising
 a common aliphatic medium comprising at least 50 wt.-% of one or more aliphatic hydrocarbons having a boiling point in the range of 45° C. to 80° C. at a pressure of 1013 hPa, and 
 a monomer mixture comprising at least one monoolefin monomer, at least one multiolefin monomer and either no or at least one other co-polymerizable monomer in a mass ratio of monomer mixture to common aliphatic medium of from 40:60 to 95:5, preferably from 50:50 to 85:15 and more preferably from 61:39 to 80:20; 
 
 II) polymerizing the monomer mixture within the reaction medium to form a rubber solution comprising a rubber polymer which is at least substantially dissolved in the medium comprising the common aliphatic medium and residual monomers of the monomer mixture; 
 III) separating residual monomers of the monomer mixture from the rubber solution to form a separated rubber solution comprising the rubber polymer and the common aliphatic medium, 
 IV) halogenating the rubber polymer in the separated rubber solution to obtain fluid A, a solution comprising the halogenated rubber and the common aliphatic medium, 
 
     
     
         16 . The process pursuant to  claim 15 , characterized in that step IV) is performed using a bromination agent and the bromination agent is at least partially reoxidized using an oxidizing agent. 
     
     
         17 . The use of extruders or kneaders in a process according to  claims 1  to  16 .