Cardable hydrophobic polypropylene fiber, material and method for preparation thereof

Abstract

A method for placing hydrophobic polyolefin fiber in condition for cutting, carding and production of nonwoven material without substantial sacrifice in desired hydrophobic properties in the corresponding nonwoven, by utilization of a sequential treatment of the fiber with a neutralized phosphoric acid ester and a polysiloxane of defined classes.

I claim: 
     
       1. A method for preparing essentially hydrophobic polyolefin-containing spun fiber or filament for cutting and carding steps in the production of hydrophobic nonwoven material, comprising A. initially treating corresponding continuous spun fiber or filament with an effective amount .Iadd.for fiber or filament processing to avoid difficulties generated by friction and accumulated static charge .Iaddend.of a first modifier composition comprising (a) about 70%-100% by weight of modifier composition of at least one neutralized phosphoric acid ester represented by the formula ##STR3##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal,   n and m are individually defined as positive numbers of not less than . ˜!. 1, the sum of which is about 3; and     (b) up to about 30% by weight of modifier composition of at least one polysiloxane represented by the formula ##STR4##  wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   o is defined as a positive number . .within the range.!. of .Iadd.at least .Iaddend.about 10 . .-50 or higher.!.;       B. crimping the resulting continuous fiber or filament in a crimper;   C. applying to said fiber or filament an effective amount .Iadd.for fiber or filament processing to avoid difficulties generated by friction and accumulated static charge .Iaddend.of a second modifier composition comprising (a) about 70%-100%, by weight of second modifier composition, of at least one polysiloxane represented by formula (2) and   (b) up to about 30%, by weight of second modifier composition, of at least one neutralized phosphoric acid ester represented by formula (1);     D. processing the resulting modifier-treated fiber or filament to obtain one or more webs for bonding; and   E. bonding the resulting web to obtain a desired hydrophobic nonwoven material.   
     
     
       2. The method of claim 1 wherein initial treatment of said continuous spun fiber or filament is effected using about 100%, by weight of first modifier composition, of at least one neutralized phosphoric acid ester represented in formula (1). 
     
     
       3. The method of claim 1 wherein the Alk-O group of the neutralized ester is defined as a straight 1-4 carbon alkoxy group; n is 2; and m is 1. 
     
     
       4. The method of claim 1 wherein the second modifier composition is topically applied upstream of said crimper. 
     
     
       5. The method of claim 1 wherein the second modifier composition is topically applied to an at least partially crimped continuous spun fiber or filament. 
     
     
       6. The method of claim 1 wherein the "D" processing step comprises a fiber cutting and carding operation. 
     
     
       7. The method of claim 1 wherein the "D" "E" steps comprise a spun bonding operation. 
     
     
       8. A . .Crimped.!. .Iadd.crimped .Iaddend.essentially hydrophobic polyolefin-containing fiber obtained by A. initially treating corresponding continuous spun fiber or filament with an effective amount .Iadd.for fiber or filament processing to avoid difficulties generated by friction and accumulated static charge .Iaddend.of a first modifier composition comprising (a) about 70%-100% by weight of modifier composition of at least one neutralized phosphoric acid ester represented by the formula ##STR5##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than . ˜!. 1, the sum of which is about 3; and     (b) up to about 30% by weight of modifier composition of at least one polysiloxane represented by the formula ##STR6##  wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   o is defined as a positive number . .within the range.!. of .Iadd.at least .Iaddend.about 10 . .-50 or higher.!.;       B. crimping and applying to said fiber or filament an effective amount .Iadd.for fiber or filament processing to avoid difficulties generated by friction and accumulated static charge .Iaddend.of a second modifier composition comprising (a) about 70%-100%, by weight of second modifier composition, of at least one polysiloxane represented by formula (2), and   (b) up to about 30%, by weight of second modifier composition, of at least one neutralized phosphoric acid ester represented by formula . .(I).!. .Iadd.(1).Iaddend..     
     
     
       9. The fiber of claim 8 wherein initial treatment of said continuous spun fiber or filament is effected using about 100%, by weight of first modifier composition, of at least one neutralized phosphoric acid ester represented in formula (1). 
     
     
       10. The fiber of claim 8 wherein the Alk-O group of the neutralized ester is defined as a straight 1-4 carbon alkoxy group; n is 2; and m is 1. 
     
     
       11. The fiber of claim 10 wherein the second modifier composition is topically applied upstream of said crimper. 
     
     
       12. The fiber of claim 9 wherein the second modifier composition is topically applied to an at least partially crimped continuous spun fiber or filament. 
     
     
       13. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 1. 
     
     
       14. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 2. 
     
     
       15. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 3. 
     
     
       16. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 4. 
     
     
       17. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 5. 
     
     
       18. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 6. 
     
     
       19. A nonwoven material . .obtained in accordance with.!. .Iadd.produced by the method recited in .Iaddend.claim 7. .Iadd. 
     
     
       20.  The method of claim 1, wherein o is defined as a positive number of about 10 to 50. .Iaddend..Iadd.21. The fiber of claim 8, wherein o is 
     
     
        defined as a positive number of about 10 to 50. .Iaddend..Iadd.22.  The method for preparing essentially hydrophobic polyolefin-containing fiber or filament, comprising: treating continuous polyolefin-containing fiber or filament with a first composition comprising at least one neutralized phosphoric acid ester represented by the formula ##STR7##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than 1, the sum of which is about 3;   crimping the polyolefin-containing fiber or filament subsequent to treatment with the first composition; and   treating the crimped polyolefin-containing fiber or filament with a second composition comprising at least one neutralized phosphoric acid ester represented by the formula ##STR8##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than 1, the sum of which is about 3.   
     
     
        .Iaddend..Iadd.23.  The method according to claim 22, wherein said first composition further comprises at least one polysiloxane. .Iaddend..Iadd.24. The method according to claim 23, wherein said at least one polysiloxane comprises at least one polysiloxane represented by the formula ##STR9## wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   
     
     
       o is defined as a positive number of at least about 10. .Iaddend..Iadd.25. The method according to claim 24, wherein o is defined as a positive 
     
     
        member of about 10 to 50. .Iaddend..Iadd.26.  The method according to claim 24, wherein the treating comprises applying from about 0.09% to 0.5% of the first composition based on the weight of the fiber or filament. .Iaddend..Iadd.27. The method according to claim 22, wherein said second composition further comprises at least one polysiloxane. .Iaddend..Iadd.28. The method according to claim 27, wherein said at least one polysiloxane comprises at least one polysiloxane represented by the formula ##STR10## wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   
     
     
       o is defined as a positive number of at least about 10. .Iaddend..Iadd.29. The method according to claim 28, wherein the treating the continuous polyolefin-containing fiber or filament with a first composition comprises applying from about 0.09% to 0.5% of the composition based on the weight of the fiber or filament, and the treating the crimped polyolefin-containing fiber or filament with a second composition comprises applying from about 0.05% to 0.20% of the second composition based on the weight of the fiber or filament. .Iaddend..Iadd.30. The method according to claim 27, further comprising processing the polyolefin-containing fiber or filament subsequent to treatment with the second composition to obtain at least one web, and bonding the at least one web to obtain a hydrophobic nonwoven material. .Iaddend..Iadd.31. The method according to claim 22, further comprising processing the polyolefin-containing fiber or filament subsequent to treatment with the second composition to obtain at least one web, and bonding the at least 
     
     
        one web to obtain a hydrophobic nonwoven material. .Iaddend..Iadd.32.  The method according to claim 22, wherein the treating comprises applying from about 0.09% to 0.5% of the first composition based on the weight of the fiber or filament. .Iaddend..Iadd.33. The method according to claim 22, wherein the treating the continuous polyolefin-containing fiber or filament with a first composition comprises applying from about 0.09% to 0.5% of the composition based on the weight of the fiber or filament, and the treating the crimped polyolefin-containing fiber or filament with a second composition comprises applying from about 0.05% to 0.20% of the second composition based on the weight of the fiber or filament. 
     
     
        .Iaddend..Iadd.34.  An essentially hydrophobic polyolefin-containing fiber or filament, comprising: polyolefin-containing fiber or filament including a coating comprising at least one neutralized phosphoric acid ester represented by the formula ##STR11## wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than 1, the sum of which is about 3.   
     
     
        .Iaddend..Iadd.35.  The fiber or filament according to claim 34, wherein said coating further comprises at least one polysiloxane. 
     
     
        .Iaddend..Iadd.  .  The fiber or filament according to claim 35, wherein said at least one polysiloxane comprises at least one polysiloxane represented by the formula ##STR12## wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   
     
     
       o is defined as a positive number of at least about 10. .Iaddend..Iadd.37. The fiber or filament according to claim 36, wherein o is defined as a positive number of about 10 to 50. .Iaddend..Iadd.38. The fiber or filament according to claim 35, wherein said fiber or filament is crimped. 
     
     
        .Iaddend..Iadd.39.  A nonwoven material comprising the fibers of claim 35. .Iaddend..Iadd.40. The fiber or filament according to claim 34, wherein said fiber or filament is crimped. .Iaddend..Iadd.41. A nonwoven material 
     
     
        comprising the fibers of claim 34. .Iaddend..Iadd.42.  A method for preparing essentially hydrophobic polyolefin-containing spun fiber or filament for cutting and carding steps in the production of hydrophobic nonwoven material, comprising A. initially treating corresponding continuous spun fiber or filament with from about 0.09% to 0.5% based on the weight of the fiber or filament of a first modifier composition comprising (a) about 70%-100% by weight of modifier composition of at least one neutralized phosphoric acid ester represented by the formula ##STR13##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than 1, the sum of which is about 3; and   (b) up to about 30% by weight of modifier composition of at least one polysiloxane represented by the formula ##STR14## wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   o is defined as a positive number of at least about 10;       B. crimping the resulting continuous fiber or filament in a crimper;   C. applying to said fiber or filament from about 0.05% to 0.20% based on the weight of the fiber or filament of a second modifier composition comprising (a) about 70%-100%, by weight of second modifier composition, of at least one polysiloxane represented by formula (2), and   (b) up to about 30%, by weight of second modifier composition, of at least one neutralized phosphoric acid ester represented by formula (1);     D. processing the resulting modifier-treated fiber or filament to obtain one or more webs for bonding; and   E. bonding the resulting web to obtain a desired hydrophobic nonwoven   
     
     
        material. .Iaddend..Iadd.43.  A crimped essentially hydrophobic polyolefin-containing fiber obtained by A. initially treating corresponding continuous spun fiber or filament with from about 0.09% to 0.5% based on the weight of the fiber or filament of a first modifier composition comprising (a) about 70%-100% by weight of modifier composition of at least one neutralized phosphoric acid ester represented by the formula ##STR15##  wherein Alk is individually defined as a lower alkyl group, R is defined as an amino group or an alkali metal, n and m are individually defined as positive numbers of not less than 1, the sum of which is about 3; and   (b) up to about 30% by weight of modifier composition of at least one polysiloxane represented by the formula ##STR16## wherein X and Y are defined as hydrophobic chemical end groups, R' is individually defined as a lower alkyl group, and   o is defined as a positive number of at least about 10;       B. crimping and applying to said fiber or filament from about 0.05% to 0.20% based on the weight of the fiber or filament of a second modifier composition comprising (a) about 70%-100%, by weight of second modifier composition, of at least one polysiloxane represented by formula (2), and   (b) up to about 30%, by weight of second modifier composition, of at least one neutralized phosphoric acid ester represented by formula (1). .Iaddend.