Aerated polypropyelene compositions exhibiting specific emission

Abstract

A polypropylene composition comprising oligomers having a semi-volatile organic condensable (FOG,VDA 278 October 2011), content of 50 μg/g to about 400 μg/g of the total polypropylene composition, and volatile organic compounds (VOC,VDA 278 October 2011) in an amount of less than 80 μg/g of the total polypropylene composition, wherein the weight ratio of said oligomers versus said volatiles is more than about 5.0, wherein the polypropylene composition has an MFR2 (ISO 1133, 230° C., 2.16 kg) of 10 g/10 min or higher, wherein the polypropylene composition a flexural modulus (ISO 178 on injection moulded specimens of 80×10×4 mm prepared in accordance with ISO 294-1:1996) of from 1000 to 2000 MPa, and wherein the total quantity of slip agent is at least 500 ppm.

1 . A propylene composition comprising:
 semi-volatile organic condensable oligomers (FOG,VDA 278 October 2011) in an amount of 50 μg/g to about 400 μg/g of the total polypropylene composition, and   volatile organic compounds (VOC,VDA 278 October 2011) in an amount of less than 80 μg/g of the total polypropylene composition,   wherein the weight ratio of said semi-volatile organic condensable oligomers versus said volatile organic compounds is more than about 5.0,   wherein the polypropylene composition has an MFR 2  (ISO 1133, 230° C., 2.16 kg) of 10 g/10_min or higher,   wherein the polypropylene composition has a flexural modulus (ISO 178 on injection moulded specimens of 80×10×4 mm prepared in accordance with ISO 294-1:1996) of from 1000 to 6000 MPa, and   wherein the total quantity of slip agent is at least 500 ppm.   
     
     
         2 . The polypropylene composition according to  claim 1 , obtainable by
 i) blending:   polypropylene,   filler,   slip agent,   optional HDPE,   optional plastomer, and   optional pigment,   in the presence of additives to obtain a blend, and further   ii) subjecting the blend to a process comprising the steps of:   a) providing an aeration vessel having   at least one inlet for aeration gas,   at least one outlet for exhaust gas,   an inlet for a raw polypropylene composition at the top of the aeration vessel,   an outlet for the polypropylene composition at the bottom of the aeration vessel,   wherein the polypropylene composition is present as a packed bed,   b) initiating a counter-current flow of the polypropylene composition and aeration gas,   c) by:   feeding the raw polypropylene composition having a volatile organic compound content (VOC, VDA 278 October 2011) of greater than about 150 μg/g and a semi-volatile organic condensable content of greater than about 350 μg/g (FOG,VDA 278 October 2011), into said aeration vessel from the top,   feeding the aeration gas into said aeration vessel via the at least one inlet at the bottom;   withdrawing the exhaust gas via the outlet for exhaust gas;   withdrawing the aerated polypropylene composition via the outlet at the bottom of the aeration vessel,   d) maintaining said aeration gas flow for an aeration time of from 3 to 96 hours,   wherein, the temperature of the gas is from 100° C. to 140° C., and wherein, the Reynolds number of the gas flow is from 5 to 150, whereby the Reynolds number for the flow of aeration gas through the packed bed is defined by formula (I):
   Re=(ρv s   D )/μ  (I)
 
   where:   ρ is the density of the aeration gas at the temperature used (kg/m 3 ),   μ is the kinematic viscosity of the aeration gas at the temperature used (kg/ms),   v s  is the superficial velocity, defined as Q/A where Q is the volume flow rate of the aeration gas, (m 3 /s) and A is the cross sectional area (m 2 ), and   D is the diameter (m) of the particles, and wherein no further clip agent is added to the composition after step d).   
     
     
         3 - 9 . (canceled) 
     
     
         10 . The polypropylene composition according to  claim 1 , wherein the polypropylene composition has a puncture energy of from 35 to 45 J. 
     
     
         11 . The polypropylene component composition according to  claim 1 , wherein the filler is selected from the group consisting of talc, glass, and mixtures thereof. 
     
     
         12 . (canceled) 
     
     
         13 . The polypropylene composition according to  claim 1 , wherein the propylene composition comprises semi-volatile organic condensable oligomers (FOG,VDA 278 October 2011) in an amount of 50 μg/g to about 170 μg/g of the total polypropylene composition, and volatile organic compounds (VOC,VDA 278 October 2011) in an amount of 20 μg/g or less of the total polypropylene composition. 
     
     
         14 . The polypropylene composition according to  claim 1 , wherein the slip agent is a fatty acid amide. 
     
     
         15 . The polypropylene composition according to  claim 1 , wherein the slip agent is erucamide or oleamide. 
     
     
         16 . The polypropylene composition according to  claim 1 , wherein the VDA 277 value is less than 1. 
     
     
         17 . The polypropylene composition according to  claim 1 , wherein the fogging gravimetric is less than 1.1, and/or
 wherein the VDA 270 value is 3 or less.   
     
     
         18 . The polypropylene composition according to  claim 1 , wherein the polypropylene composition has an MFR 2  (ISO 1133, 230° C., 2.16 kg) of from 10 to 25 g/10 min.