Process for producing a filled polymer material

Abstract

The invention relates to a method for producing a thermoplastic polymer material that is filled with at least one filler, preferably calcium carbonate CaCO 3 , sensitive to hydrolytic degradation and optionally hygroscopic, and produced by way of polycondensation, particularly PET, wherein under vacuum conditions, constant stirring or mixing and an increased temperature, a mixture of not yet melted, optionally softened, polymer materials comprising the filler is produced, wherein for this purpose a filler, which at the time of addition has not been predried and has a residual moisture (H 2 O) of more than 500 ppm, particularly more than 1000 ppm, is used.

What is claimed is: 
     
         1 . A process for producing a thermoplastic polymer polycondensate material, which is sensitive to hydrolytic degradation and/or is hygroscopic, the process comprising mixing at least one filler with a not yet molten and/or softened polymer material under vacuum conditions, constant agitation, thorough mixing and elevated temperature, wherein the filler has not been pre-dried at the time of mixing and has a residual moisture (H 2 O) of more than 500 ppm. 
     
     
         2 . The process according to  claim 1 , wherein the at least one filler is an inert powdery mineral. 
     
     
         3 . The process according to  claim 1 , wherein a non-surface-treated or uncoated filler is used as filler. 
     
     
         4 . The process according to  claim 1 , wherein a filler with an average grain size or a D 50 value of less than 50 μm, and/or with a specific surface of 2 to 11 m 2 /g, is used as filler. 
     
     
         5 . The process according to  claim 1 , wherein the polymer material is present in a softened state and has a temperature of above 30° C. below its VICAT softening point (10 N) but not below its melting point at the time of the addition of at least a partial amount. 
     
     
         6 . The process according to  claim 1 , wherein the not yet molten, and/or softened material or the thermoplastic polymer polycondensate material is heated in at least one receiving container or reactor that can be evacuated under constant mixing or movement and/or comminution at a temperature below the melting temperature, and as a result is crystallized, dried and/or cleaned at the same time, where, for the mixing and/or heating of the thermoplastic polymer polycondensate material, at least one comminution or mixing tool is used that is optionally arranged on several superimposed levels, which can rotate and comprises working edges that act on the matter in a comminuting and/or mixing manner, and wherein the processing takes place under a vacuum of <150 mbar, and the thermoplastic polycondensate polymer materials remain in the reactor for an average dwell time of 10 min to 200 min. 
     
     
         7 . The process according to  claim 1 , wherein the process is carried out in one stage in a single reactor or in the infeed area of an extruder, and that the thermoplastic polycondensate polymer material, is heated, dried, crystallized and cleaned in a single work procedure. 
     
     
         8 . The process according to  claim 1 , wherein the process is carried out in several stages, in which two or more receiving containers or reactors are arranged in series and/or in parallel and the thermoplastic polycondensate polymer material to be processed passes through these containers sequentially, wherein the process conditions are applied for an upstream pre-treatment and/or for a last-loaded container, which thermoplastic polycondensate polymer material in the upstream pre-treatment and/or last-loaded container is brought to a temperature close to the process temperature of the main treatment. 
     
     
         9 . The process according to  claim 8 , wherein the thermoplastic polycondensate polymer material is subjected in the first stage to a pre-treatment, by being loaded with mechanical energy, as a result of which and, upon elevated temperature, it is dried and optionally crystallized at the same time, and that subsequently a main treatment of the thermoplastic polycondensate polymer material takes place in a second stage that precedes in any case the plasticizing and/or melting, a second stage the thermoplastic polycondensate polymer material is again dried and further crystallized under vacuum conditions by being loaded with mechanical energy under movement. 
     
     
         10 . The process according to  claim 1 , wherein the thermoplastic polycondensate polymer material is subjected to a pre-treatment in a continuous flow and/or that the process is carried out continuously or discontinuously or as a batch process. 
     
     
         11 . The process according to  claim 1 , wherein the fillers are used with such a residual moisture and in such an amount that the moisture in the total system and the moisture of the mixture are less than 100 ppm. 
     
     
         12 . The process according to  claim 1 , wherein the mixture is subjected after the workup has taken place by way of conclusion to an optional compression step. 
     
     
         13 . The process of  claim 1  wherein, thermoplastic polymer polycondensate material is PET, the at least one filler is calcium carbonate (CaCO 3 ), and the residual moisture (H 2 O) is more than 1000 ppm. 
     
     
         14 . The process according to  claim 2 , wherein the inert powdery mineral is one of kaolins, silicates, titanium dioxide, or calcium carbonate (CaCO 3 ). 
     
     
         15 . The process of  claim 4 , wherein the filler average grain size or a D 50 is between 2 and 15 μm and/or the specific surface of 5 to 9 m 2 /g. 
     
     
         16 . The process of  claim 1 , wherein the polymer material is present in a softened state and has a temperature of above 30° C. below its VICAT softening point (10 N) but not below its melting point at the time of the addition of the entire amount of the filler. 
     
     
         17 . The process according to  claim 6 , wherein the material to be treated or the thermoplastic polycondensate polymer material is heated above the glass transition temperature of the thermoplastic polycondensate polymer material, and is crystallized, dried and/or cleaned in one step, in which for the mixing and/or heating of the thermoplastic polycondensate polymer material to a temperature is from 130° to 210° C., the at least one comminution or mixing tool can rotate about a vertical axis, the heating takes place by loading with mechanical energy, the processing takes place under a vacuum <50 mbar, and the thermoplastic polycondensate polymer materials remain in the reactor for an average dwell time of 40 min to 120 min. 
     
     
         18 . The process according to  claim 17 , wherein the processing takes place under a vacuum <20 mbar. 
     
     
         19 . The process according to  claim 17 , wherein the processing takes place under a vacuum between 0.1 to 2 mbar. 
     
     
         20 . The process according to  claim 7 , wherein the process is carried out in a single reactor with pre-drying and/or with pre-crystallization of the plastic material. 
     
     
         21 . The process according to  claim 7 , wherein the process is carried out in a single reactor without pre-drying and/or without pre-crystallization of the plastic material. 
     
     
         22 . The process according to  claim 7 , wherein the process is carried out in a single reactor with pre-drying and/or without pre-crystallization of the plastic material. 
     
     
         23 . The process according to  claim 7 , wherein the process is carried out in a single reactor without pre-drying and/or with pre-crystallization of the plastic material. 
     
     
         24 . The process according to  claim 8 , wherein the process is carried out in two stages and the pre-treatment is an upstream pre-treatment. 
     
     
         25 . The process according to  claim 9 , wherein the main treatment takes place at a temperature that is elevated in comparison to the pre-treatment, and the temperature of the main treatment is maintained below the plasticizing temperature and/or melting temperature of the thermoplastic polycondensate polymer material. 
     
     
         26 . The process according to  claim 10 , wherein the process is carried out discontinuously or as a batch process. 
     
     
         27 . The process according to  claim 12 , wherein the optional compression step is a melting and/or an extrusion. 
     
     
         28 . The process according to  claim 1 , wherein the at least one filler is mixed in with the not yet molten and/or softened polymer material in a container having top, middle and bottom loading positions and wherein the at least one filler added to the not yet molten and/or softened polymer in the top upper third loading position. 
     
     
         29 . The process according to  claim 28 , wherein the at least one filler is Calcium Carbonate (CaCO 3 ).