Compositions of polyesters and sepiolite-type clays

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 . The product of  claim 10  wherein said polyester has a melting point of about 100° C. or higher.  
   
   
       12 . The product of the process of  claim 1 .  
   
   
       13 . The product of the process of  claim 2 ,  
   
   
       14 . The product as recited in  claim 10  further comprising further comprising a solid particulate filler exclusive of said sepiolite-type clay.  
   
   
       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 . The product as recited in  claim 14  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.  
   
   
       17 . An article of manufacture comprising the product of  claim 12 .  
   
   
       18 . The article of  claim 17  wherein said article is an appearance part.  
   
   
       19 . The article as recited in  claim 18  which is pigmented.  
   
   
       20 . The article as recited in  claim 18  which is coated.  
   
   
       21 . The article part as recited in  claim 18  which is an automotive body panel, appliance part, power tool housing, electronic cabinet or housing, exterior or interior panel for a vehicle, decorative interior panel for a building, furniture, or telephone or telephone equipment.  
   
   
       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) 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.  
   
   
       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 . A process for coating substrates assembled from metal parts and at least one plastic part, with visible plastic surfaces, comprising the successive steps of: 
 a. electrodeposition coating the substrates, removing non-deposited electrodeposition coating agent from the substrate and thermally cross-linking the deposited electrodeposition coating and thereby forming an electrodeposition coating primer on the metal surfaces,    b. application and curing of at least one additional coating at least on all the visible metal and plastic surfaces, provided that at least some of the plastic parts make up the visible plastic surfaces of the substrate, and at least some of the plastic parts have a composition which comprises the product of  claim 22 , and wherein a melting point of the polyester is about 200° C. or higher.    
   
   
       31 . The process of  claim 30 , wherein the substrates are automobile bodies.  
   
   
       32 . The process of  claim 31 , wherein the plastic parts are selected from the group consisting of fenders, hoods, doors, lift-up tailgates, trunk lids, tank caps, bumpers, protective moldings, side panels, body sills, mirror housings, handles, spoilers and hub caps.  
   
   
       33 . Coated substrates which are coated according to the process of  claim 30 .  
   
   
       34 . An automotive vehicle manufactured according to a method which comprises the process of  claim 30 .  
   
   
       35 . The automotive vehicle of  claim 34  wherein said vehicle is an automobile, truck, snowmobile, construction vehicle, or farm equipment vehicle.  
   
   
       36 . The product of the process of  claim 3 .  
   
   
       37 . The product of the process of  claim 4 .  
   
   
       38 . The product of the process of  claim 8 .  
   
   
       39 . The product of the process of  claim 11.