Method for the preparation of a poly (arylene ether)-polyolefin composition, and composition prepared thereby

Abstract

A poly(arylene ether)-polyolefin composition is prepared by melt-blending a poly(arylene ether) and a compatibilizer to form a first blend, and melt-blending the first blend and a polyolefin to form a second blend. The composition lacks an unhydrogenated block copolymer, a poly(alkenyl aromatic) resin, or both. Multiple mixing elements, low throughput, and high extruder rotations per minute may be used to achieve high energy mixing of the first and second blends. Compositions prepared by the method exhibit an improved balance of impact strength, stiffness, and heat resistance, as well as reduced variability of physical properties.

1 . A method of preparing a thermoplastic composition, comprising: 
 melt-blending 
 about 10 to about 70 weight percent of a poly(arylene ether), and  
 about 0.5 to about 30 weight percent of a compatibilizer  
 to form a first intimate blend; and  
   melt-blending 
 the first intimate blend, and  
 about 10 to about 80 weight percent of a polyolefin  
 to form a second intimate blend;  
   wherein the thermoplastic composition is substantially free of at least one component selected from (a) an unhydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene, and (b) a poly(alkenyl aromatic) resin; and    wherein all weight percents are based on the total weight of the composition.    
     
     
         2 . The method of  claim 1 , wherein the melt-blending to form a first intimate blend comprises heating to a temperature of about 180° C. to about 400° C.  
     
     
         3 . The method of  claim 1 , wherein the melt-blending to form a first intimate blend comprises mixing with at least two mixing elements.  
     
     
         4 . The method of  claim 1 , wherein the melt-blending to form a first intimate blend and the melt-blending to form a second intimate blend collectively comprise mixing with a mixing energy input of at least about 0.20 kW-hr/kg.  
     
     
         5 . The method of  claim 1 , wherein the first intimate blend further comprises a polyolefin in an amount not greater than that of the polyolefin added during formation of the second intimate blend.  
     
     
         6 . The method of  claim 1 , wherein the poly(arylene ether) comprises a plurality of structural units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein for each structural unit, each Q 1  is independently halogen, primary or secondary C 1 -C 8  alkyl, phenyl, C 1 -C 8  haloalkyl, C 1 -C 8  aminoalkyl, C 1 -C 8  hydrocarbonoxy, or C 2 -C 8  halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q 2  is independently hydrogen, halogen, primary or secondary C 1 -C 8  alkyl, phenyl, C 1 -C 8  haloalkyl, C 1 -C 8  aminoalkyl, C 1 -C 8  hydrocarbonoxy, or C 2 -C 8  halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms.  
     
     
         7 . The method of  claim 6 , wherein each Q 1  is independently C 1 -C 4  alkyl or phenyl, and each Q 2  is independently hydrogen or methyl.  
     
     
         8 . The method of  claim 1 , wherein the poly(arylene ether) has an intrinsic viscosity of about 0.2 to about 0.6 dL/g as measured in chloroform at 25° C.  
     
     
         9 . The method of  claim 1 , wherein the poly(arylene ether) comprises a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol.  
     
     
         10 . The method of  claim 1 , wherein the compatibilizer comprises a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene compound.  
     
     
         11 . The method of  claim 10 , wherein the hydrogenated block copolymer comprises: 
 (A) at least one block derived from an alkenyl aromatic compound having the formula                          wherein R 2  and R 3  each represent a hydrogen atom, a C 1 -C 8  alkyl group, or a C 2 -C 8  alkenyl group; R 4  and R 8  each represent a hydrogen atom, a C 1 -C 8  alkyl group, a chlorine atom, or a bromine atom; and R 5 -R 7  each independently represent a hydrogen atom, a C 1 -C 8  alkyl group, or a C 2 -C 8  alkenyl group, or R 4  and R 5  are taken together with the central aromatic ring to form a naphthyl group, or R 5  and R 6  are taken together with the central aromatic ring to form a naphthyl group; and    (B) at least one block derived from a conjugated diene, in which the aliphatic unsaturated group content in the block (B) is reduced by hydrogenation.    
     
     
         12 . The method of  claim 10 , wherein the hydrogenated block copolymer is hydrogenated to such a degree that less than 20% of the aliphatic unsaturation derived from the conjugated diene remains unreduced.  
     
     
         13 . The method of  claim 10 , wherein the hydrogenated block copolymer has an alkenyl aromatic content of about 10 to about 90 weight percent.  
     
     
         14 . The method of  claim 10 , wherein the hydrogenated block copolymer has an alkenyl aromatic content of about 50 to about 90 weight percent.  
     
     
         15 . The thermoplastic composition of  claim 10 , wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer.  
     
     
         16 . The thermoplastic composition of  claim 10 , wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene) diblock copolymer.  
     
     
         17 . The method of  claim 1 , wherein the compatibilizer comprises a polyolefin-poly(alkenyl aromatic) copolymer selected from polyolefin-poly(alkenyl aromatic) graft copolymers, polyolefin-poly(alkenyl aromatic) diblock copolymers, polyolefin-poly(alkenyl aromatic) multiblock copolymers, polyolefin-poly(alkenyl aromatic) radial block copolymers, and mixtures thereof.  
     
     
         18 . The method of  claim 17 , wherein the polyolefin-poly(alkenyl aromatic) copolymer comprises a polypropylene-polystyrene graft copolymer comprising about 50 to about 85 weight percent of a propylene polymer backbone and about 15 to about 50 weight percent of one or more styrene polymer grafts.  
     
     
         19 . The method of  claim 1 , wherein the polyolefin comprises a homopolymer or copolymer having at least about 80 weight percent of units derived from polymerization of ethylene, propylene, butylene, or a mixture thereof.  
     
     
         20 . The method of  claim 1 , wherein the polyolefin is a propylene polymer comprising a homopolymer of polypropylene; or a random, graft, or block copolymer of propylene and at least one olefin selected from ethylene and C 4 -C 10  alpha-olefins; with the proviso that the copolymer comprises at least about 80 weight percent of repeating units derived from propylene.  
     
     
         21 . The method of  claim 1 , wherein the polyolefin comprises a homopolypropylene.  
     
     
         22 . The method of  claim 1 , wherein the first intimate blend further comprises about 1 to about 20 weight percent of an unhydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene compound; wherein the unhydrogenated block copolymer comprises a styrene-butadiene diblock copolymer or a styrene-butadiene-styrene triblock copolymer.  
     
     
         23 . The method of  claim 1 , wherein the first intimate blend further comprises about 1 to about 20 weight percent of an unhydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene compound.  
     
     
         24 . The method of  claim 23 , wherein the wherein the unhydrogenated block copolymer comprises a styrene-butadiene diblock copolymer or a styrene-butadiene-styrene triblock copolymer.  
     
     
         25 . The method of  claim 1 , wherein the first intimate blend and/or the second intimate blend further comprises a reinforcing filler.  
     
     
         26 . The method of  claim 1 , wherein the first intimate blend and/or the second intimate blend further comprises an additive selected from stabilizers, mold release agents, processing aids, flame retardants, drip retardants, nucleating agents, UV blockers, dyes, pigments, antioxidants, antistatic agents, and combinations comprising at least one of the foregoing additives.  
     
     
         27 . The method of  claim 1 , wherein 
 wherein the poly(arylene ether) comprises a poly(2,6-dimethyl-1,4-phenylene ether), a poly(2,6-dimethyl-1,4-phenylene ether-co-2,3,6-trimethyl-1,4-phenylene ether), or a mixture thereof;    wherein the compatibilizer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer;    wherein the polyolefin comprises a homopolypropylene; and    wherein the thermoplastic composition is substantially free of at least one component selected from (a) an unhydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene, and (b) a poly(alkenyl aromatic) resin.    
     
     
         28 . A method of preparing a thermoplastic composition, comprising: 
 melt blending 
 a poly(arylene ether) and  
 a compatibilizer  
 to form a first intimate blend; and  
   melt blending 
 the first intimate blend and  
 a polyolefin  
 to form a thermoplastic composition consisting essentially of the poly(arylene ether), the compatibilizer, and the polyolefin.