Sheet and Method of Making Sheet for Support Structures and Tires

Abstract

A planar sheet comprises a plurality of polyamide yarns having a yarn modulus of from 3.7 to 6.8 N/dtex, an elongation to break of from 2.9 to 4.7% and a denier of from 130 to 15,000 and a plurality of steel wires wherein the steel wire is provided with a first crimp and a second crimp, the first crimp lying in a plane that is substantially different from the plane of the second crimp. The first and second crimp pitches and amplitudes of the steel wire are such that, when the steel wire and polyamide yarns are combined, the elongation to break of the wire is similar to that of the polyamide yarn. The wires and yarns are arranged such that they are oriented parallel to each other within the planar sheet. The sheet has utility in the construction of elastomeric components for tires and belts.

1 . A planar sheet, comprising:
 (a) a plurality of polyamide yarns having a yarn modulus of from 3.7 to 6.8 N/dtex, an elongation to break of from 2.9 to 4.7% and a denier of from 130 to 15,000,   (b) a plurality of steel wires having a major cross sectional dimension of from 0.04 to 1.10 mm, wherein
 (1) the steel wire is provided with a first crimp and a second crimp, the first crimp lying in a plane that is at least 20° different from the plane of the second crimp, 
 (2) the first and second crimp pitches and amplitudes of the steel wire are such that the elongation to break of the wire is no greater than 20% different from that of the polyamide yarn, 
 (3) the steel wire has a composition comprising a minimum carbon content of 0.60 to 1.10%, a manganese content ranging from 0.20% to 0.90% and a silicon content ranging from 0.10% to 0.90%, and 
 (4) the steel wires and polyamide yarns are oriented parallel to each other within the planar sheet. 
   
     
     
         2 . The planar sheet of  claim 1 , wherein the polyamide yarn comprises poly (paraphenylene terephthalamide) filaments. 
     
     
         3 . The planar sheet of  claim 1 , wherein the polyamide yarn has a modulus of from 3.7 to 6.0 N/dtex. 
     
     
         4 . The planar sheet of  claim 1 , wherein the polyamide yarn has a modulus of from 4.4 to 5.4 N/dtex. 
     
     
         5 . The planar sheet of  claim 1 , wherein the polyamide yarn has an elongation to break of from 3.0 to 4.0%. 
     
     
         6 . The planar sheet of  claim 1 , wherein the cross section of the steel wire round or essentially round. 
     
     
         7 . A support structure for a tire, comprising the planar sheet of  claim 1  in the form of a belt, a carcass, or a bead. 
     
     
         8 . A tire comprising the planar sheet of  claim 1 . 
     
     
         9 . A method of forming a planar sheet, comprising the steps of:
 (a) providing a plurality of polyamide yarns having a yarn modulus of from 3.7 to 6.8 N/dtex, an elongation to break of from 2.9 to 4.7% and a denier of from 130 to 15,000,   (b) optionally twisting a plurality of polyamide yarns into a cabled yarn,   (c) providing a plurality of steel wires having a major cross sectional dimension of from 0.04 to 1.10 mm and a composition comprising a minimum carbon content of from 0.60 to 1.10%, a manganese content ranging from 0.20% to 0.90%, and a silicon content ranging from 0.10% to 0.90%,   (d) determining the desired pitch, amplitude and planar arrangement of crimps to be applied to the steel wire such that the crimps lie in two planes that are at least 20° different from each other and the steel wire has an elongation to break no greater than 20% different from that of the polyamide yarn,   (e) crimping the steel wire in accordance with the crimp parameters determined in step (d),   (f) optionally twisting a plurality of steels wires into a cabled wire, and   (g) combining the desired number of steel wires and/or steel cords, and the desired number of polyamide yarns and/or polyamide cords in a planar arrangement such that all the yarns, wires and cords are oriented parallel to each other.   
     
     
         10 . A method of forming a planar sheet, comprising the steps of:
 (a) providing a plurality of polyamide yarns having a yarn modulus of from 3.7 to 6.8 N/dtex, an elongation to break of from 2.9 to 4.7% and a denier of from 130 to 15,000,   (b) providing a plurality of steel wires having a major cross sectional dimension of from 0.04 to 1.10 mm and a composition comprising a minimum carbon content of from 0.60 to 1.10%, a manganese content ranging from 0.20% to 0.90%, and a silicon content ranging from 0.10% to 0.90%,   (c) determining the desired pitch, amplitude and planar arrangement of crimps to be applied to the steel wire such that the crimps lie in two planes that are at least 20° different from each other and the steel wire has an elongation to break no greater than 20% different from that of the polyamide yarn,   (d) crimping the steel wire in accordance with the crimp parameters determined in step (c),   (e) twisting at least one crimped steel wire with at least one polyamide yarn to form a composite hybrid steel-polyamide cord into a steel cord, and   (g) combining the desired number of steel wires or cords, polyamide yarns or cords and composite hybrid steel-polyamide cords in a planar arrangement such that all the yarns, wires and cords are oriented parallel to each other.   
     
     
         11 . The method of  claim 9  or  10 , wherein the polyamide yarn comprises poly (paraphenylene terephthalamide) filaments. 
     
     
         12 . The method of  claim 9  or  10 , wherein the polyamide yarn has a modulus of from 3.7 to 6.0 N/dtex. 
     
     
         13 . The method of  claim 9  or  10 , wherein the polyamide yarn has a modulus of from 4.4 to 5.4 N/dtex. 
     
     
         14 . The method of  claim 9  or  10 , wherein the polyamide yarn has an elongation to break of from 3.0 to 4.0%. 
     
     
         15 . The method of  claim 9  or  10 , wherein the cross section of the steel wire is round or essentially round.