Multifilament yarns for reinforcing articles

Abstract

Reinforcing material for elastic articles and more particularly for automobile tires. The material is made up of multifilament synthetic linear high polymer yarns, each yarn having a plurality of filaments and each filament composed of at least two different polymers. One polymer functions as the matrix and the other polymer consists of a multiplicity of continuous cores having substantially the same length as, and being disposed uniformly throughout, the matrix. The cores are characterized by their uniformity in cross-sectional dimensions and by their substantially continuous nature. A novel system is provided for making such filaments.

What is claimed is: 
     
       1. Yarn consisting of a plurality of composite filaments, each filament comprising at least two different incompatible synthetic linear high polymers, one polymer functioning as a matrix and the other consisting of a multiplicity of continuous ultrafine cores distributed substantially uniformly throughout the longitudinal body of the matrix each core being characterized by its uniformity in cross-sectional dimension and the cross-sectional dimensions from core to core being of the same order of magnitude, said cores being further characterized by their substantially continuous nature. 
     
     
       2. Yarn according to claim 1 wherein the total weight of the cores constitute 20 to 50% by weight of the composite filaments. 
     
     
       3. Yarn according to claim 1 wherein the cores measure less than 4 microns in cross section. 
     
     
       4. Yarn according to claim 1 wherein the cores consist of polyethylene terephthalate having a relative viscosity of at least 1.5. 
     
     
       5. Yarn according to claim 1 wherein the matrix consist of a polyamide having a relative viscosity of at least 2.3. 
     
     
       6. Yarn according to claim 5 wherein the polyamide is polyhexamethylene-adipamide. 
     
     
       7. Yarn according to claim 1 wherein the number of cores in the matrix is at least 100. 
     
     
       8. Yarn according to claim 1 wherein the cores are substantially round in cross section. 
     
     
       9. A carcass fabric for reinforcing elastic articles woven from the yarn of claim 1. 
     
     
       10. Yarn according to claim 1 wherein each filament is provided with an annular zone extending along its periphery, said zone being substantially free from endless cores. 
     
     
       11. Yarn according to claim 10 wherein said zone extends radially inward from the periphery of the filaments at a distance to an amount of at highest about 20% of the radius of the filaments. 
     
     
       12. Yarn according to claim 11 wherein said zone has a thickness of 5 to 10% of the radius of the filaments.