Stabilization of polymeric structures

Abstract

A nonwoven web comprising bicomponent fibers. The fibers have continuous phases each of a first polyarylene sulfide (PAS) component and a polymer component. The polymer component may also be a second polyarylene sulfide. The first polyarylene sulfide component contains a tin or a zinc additive or both, and the first polyarylene sulfide component of any given fiber is at least partially exposed to the external surface of that fiber.

1 . A nonwoven web comprising bicomponent fibers, said fibers comprising continuous phases each of a first polyarylene sulfide (PAS) component and a polymer component, in which the first polyarylene sulfide component contains a tin or a zinc additive or both, and the first polyarylene sulfide component of any given fiber is at least partially exposed to the external surface of that fiber. 
     
     
         2 . The web of  claim 1  in which the polymer component comprises a polymer selected from the group consisting or polyether ether ketone (PEEK), polyether ketone (PEK), polyester, polypropylene, polyamide, and mixtures thereof. 
     
     
         3 . The web of  claim 2  in which the polyester comprises polyethylene terephthalate (PET), polytrimethylene terephthalate, or polybutylene terephthalate (PBT). 
     
     
         4 . The web of  claim 1  in which the second polymer component comprises a second polyarylene sulfide. 
     
     
         5 . The web of  claim 4  in which the second polyarylene sulfide is blended with a calcium salt. 
     
     
         6 . The web of  claim 5  in which the calcium salt is calcium stearate. 
     
     
         7 . The web of  claim 1  in which the tin additive is a branched carboxylate selected from the group consisting of Sn(O 2 CR) 2 , Sn(O 2 CR)(O 2 CR′), Sn(O 2 CR)(O 2 CR″), and mixtures thereof, where the carboxylate moieties O 2 CR and O 2 CR′ independently represent branched carboxylate anions and the carboxylate moiety O 2 CR″ represents a linear carboxylate anion. 
     
     
         8 . The web of  claim 7  in which the tin additive further comprises a linear tin(II) carboxylate Sn(O 2 CR″) 2 . 
     
     
         9 . The web of  claim 7  in which the sum of the branched carboxylate moieties O 2 CR and O 2 CR′ is at least about 25% on a molar basis of the total carboxylate moieties O 2 CR, O 2 CR′ and O 2 CR″ contained in the tin additive. 
     
     
         10 . The web of  claim 7  in which the radical R″ is a primary alkyl group comprising from 6 to 30 carbon atoms. 
     
     
         11 . The web of  claim 10  in which the radical R″ is substituted with a group selected form the group consisting of fluoride, chloride, bromide, iodide, nitro, hydroxyl, carboxylate, and any combination thereof. 
     
     
         12 . The web of  claim 7  in which the radicals R or R′ independently or both have a structure represented by Formula (I), 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , and R 3  are selected from the group consisting of:
 H; 
 a primary, secondary, or tertiary alkyl group having from 6 to 18 carbon atoms, optionally substituted with fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups; 
 an aromatic group having from 6 to 18 carbon atoms, optionally substituted with alkyl, fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups; and 
 a cycloaliphatic group having from 6 to 18 carbon atoms, optionally substituted with fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups; 
 with the proviso that when R 2  and R 3  are H, R 1  is: 
 a secondary or tertiary alkyl group having from 6 to 18 carbon atoms, optionally substituted with fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups; 
 an aromatic group having from 6 to 18 carbons atoms and substituted with a secondary or tertiary alkyl group having from 6 to 18 carbon atoms, the aromatic group and/or the secondary or tertiary alkyl group being optionally substituted with fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups; and 
 a cycloaliphatic group having from 6 to 18 carbon atoms, optionally substituted with fluoride, chloride, bromide, iodide, nitro, hydroxyl, and carboxyl groups. 
 
     
     
         13 . The web of  claim 7  in which the radicals R or R′ or both have a structure represented by Formula (I), and R 3  is H. 
     
     
         14 . The web of  claim 7  in which the radicals R or R′ independently or both have a structure represented by Formula (II), 
       
         
           
           
               
               
           
         
       
       wherein
 R 4  is a primary, secondary, or tertiary alkyl group having from 4 to 6 carbon atoms, optionally substituted with fluoride, chloride, bromide, iodide, nitro, and hydroxyl groups; and 
 R 5  is a methyl, ethyl, n-propyl, sec-propyl, n-butyl, sec-butyl, or tert-butyl group, optionally substituted with fluoride, chloride, bromide, iodide, nitro, and hydroxyl groups. 
 
     
     
         15 . The web of  claim 7  in which the radicals R and R′ are the same and both have a structure represented by Formula (II), R 4  is n-butyl, and R 5  is ethyl. 
     
     
         16 . The web of  claim 1  in which the tin additive is present at a concentration of about 10 weight percent or less of the weight of the first polyarylene sulfide component. 
     
     
         17 . The web of  claim 1 , in which the zinc additive is selected from the group consisting of one zinc(II) additive, zinc metal [Zn(0)], or both. 
     
     
         18 . The web of  claim 17  in which the zinc(II) additive is an organic compound or an inorganic compound or a mixture of both. 
     
     
         19 . The web of  claim 18 , wherein the zinc(II) additive is selected from the group consisting of zinc oxide, zinc stearate, zinc sulfate and mixtures thereof. 
     
     
         20 . The web of  claim 1 , wherein the zinc and tin additives are present at a total concentration of about 25 weight percent or less, based on the weight of the polyarylene sulfide. 
     
     
         21 . The web of  claim 20 , wherein the zinc additive is present at a concentration of zero to about 10 weight percent, based on the weight of the polyarylene sulfide. 
     
     
         22 . The web of  claim 4 , wherein the first polyarylene sulfide, or the second polyarylene sulfide, or both are polyphenylene sulfide.