Facilatated dispersion of nanofillers for the preparation of nanocomposites

Abstract

Compositions of thermoplastic polyesters and sepiolite-type clay in which the clay is dispersed in the polyester as often fibrous particles whose smallest dimension is less than 100 nm are made by polymerizing the polyester precursors in the presence of the clay. The compositions have good physical properties and can be melt molded into various articles. Many of these articles may be coated (painted) and are especially useful for appearance parts such as visible exterior automotive body parts.

1 . A process for manufacturing a thermoplastic polyester containing composition comprising mixing a sepiolite-type clay with at least one thermoplastic polyester precursor selected from the group consisting of
 a. at least one diacid or diester and at least one diol;   b. at least one polymerizable polyester monomer;   c. at least one linear polyester oligomer;   d. at least one macrocyclic polyester oligomer,   and subsequently polymerizing said at least one polyester precursor in the presence or absence of a solvent.   
   
   
       2 . The process as recited in  claim 1  wherein the sepiolite-type clay content in the composition so produced is 0.1 to 20 weight percent, based on the total weight of said clay and said polyester present. 
   
   
       3 . The process as recited in  claim 1  wherein said polyester consists essentially of repeat units derived from one or more of terephthalic acid, isophthalic acid and 2,6-naphthalene dicarboxylic acid, and repeat units derived from one or more of HO(CH 2 ) n OH, 1,4-cyclohexanedimethanol, HO(CH 2 CH 2 O) m CH 2 CH 2 OH, and HO(CH 2 CH 2 CH 2 CH 2 O) z CH 2 CH 2 CH 2 CH 2 OH, wherein n is an integer of 2 to 10, m is an average of 1 to 4, and z is an average of about 7 to about 40. 
   
   
       4 . The process as recited in  claim 1  wherein said polyester is poly(ethylene terephthalate), poly(1,3-propylene terephthalate), poly(1,4-butylene terephthalate), or poly(1,4-cylohexyldimethylene terephthalate), or a modified version thereof. 
   
   
       5 . The process as recited in  claim 1  wherein a continuous polyester polymerization process is used. 
   
   
       6 . The process as recited in  claim 1  wherein a batch or semibatch polyester polymerization process is used. 
   
   
       7 . The process as recited in  claim 1  wherein no additional polyester polymerization catalyst is present. 
   
   
       8 . The process as recited in  claim 1  wherein one or more additional chemically inert solid particulate materials are present. 
   
   
       9 . The process as recited in  claim 1  comprising the additional step of subjecting said composition in the liquid state to shear stress. 
   
   
       10 . The process as recited in  claim 1  wherein said sepiolite-type clay is sepiolite or attapulgite. 
   
   
       11 . (canceled) 
   
   
       12 . A product produced by the process of  claim 1 . 
   
   
       13 - 14 . (canceled) 
   
   
       15 . The product of  claim 12  additionally comprising one or more of a solid particulate filler exclusive of said sepiolite-type clay, a plasticizer, an epoxy compound or resin, and a toughener. 
   
   
       16 - 21 . (canceled) 
   
   
       22 . A process for the formation of a shaped part from a polyester, comprising the steps:
 a. preparing a polyester containing composition by mixing a sepiolite-type clay with at least one polyester precursor selected from the group consisting of
 (i) at least one diacid or diester and at least one diol; 
 (ii) at least one polymerizable polyester monomer; 
 (iii) at least one linear polyester oligomer, and 
 (iv) at least one macrocyclic polyester oligomer, 
   
     and subsequently polymerizing the at least one polyester precursor, in the presence or absence of solvent, to produce a polyester;
 b. heating a second composition comprising said polyester composition to a temperature above a melting point of said polyester, or if said polyester is amorphous above a glass transition point of said polyester; 
 c. forming the polyester nanocomposite into the desired shape; and 
 d. cooling the composition from a temperature above a melting point of said polyester to a temperature below said melting point to retain said desired shape. 
 
   
   
       23 . The process of  claim 22  wherein the sepiolite-type clay content in the polyester composition is 0.1 to 20 weight percent based on the weight of polyester plus sepiolite-type clay 
   
   
       24 . The process of  claim 22  wherein the polyester has a melting point of about 100° C. or higher; 
   
   
       25 . The process of  claim 22  wherein the polyester consists essentially of repeat units derived from one or more of terephthalic acid, isophthalic acid and 2,6-naphthalene dicarboxylic acid, and repeat units derived from one or more of HO(CH 2 ) n OH, 1,4-cyclohexanedimethanol, HO(CH 2 CH 2 O) m CH 2 CH 2 OH, and HO(CH 2 CH 2 CH 2 CH 2 O) n CH 2 CH 2 CH 2 CH 2 OH, wherein n is an integer of 2 to 10, m is an average of 1 to 4, and z is an average of about 7 to about 40. 
   
   
       26 . The process of  claim 22  wherein the polyester is poly(ethylene terephthalate), poly(1,3-propylene terephthalate), poly(1,4-butylene terephthalate), or poly(1,4-cyclohexyldimethylene terephthalate), or a modified version thereof. 
   
   
       27 . The process as recited in  claim 22  wherein said second composition further comprises a solid particulate filler exclusive of said sepiolite-type clay. 
   
   
       28 . The process of  claim 22  wherein said second composition additionally comprises one or more of a solid particulate filler exclusive of said sepiolite-type clay, a plasticizer, an epoxy compound or resin, or a toughener. 
   
   
       29 . The process as recited in  claim 27  wherein the solid particulate filler exclusive of sepiolite-type clay is present at about 0.1 to about 50 weight percent of the total composition. 
   
   
       30 - 39 . (canceled) 
   
   
       40 . The process in accordance with  claim 5  wherein said sepiolite-type clay is first mixed with at least a portion said at least one diol to form a slurry and said slurry is thereafter mixed with said at least one diacid and the remainder of said at least one diol. 
   
   
       41 . The process in accordance with  claim 40  wherein said continuous polymerization process is carried out in a continuous polymerization reactor, said reactor including an ester exchanger monomer reactor vessel, said vessel defining a top and a bottom and said slurry being fed into said bottom of said vessel. 
   
   
       42 . The process in accordance with  claim 40  wherein said slurry has approximately nine weight percent solids in the form of said sepiolite-type clay.