HIGH PERFORMANCE TIRE CORDS

Abstract

High performance textile cords having residual twist in ply-yarns in cord are used as reinforcement in bias and radial pneumatic tires. The high performance textile cords have a residual ply-yarn twist multiplier, wherein the residual ply-yarn twist multiplier is greater than 1,000 and less than 4,000 and a residual twist direction of a plurality of ply-yarns in Z or S direction is in an opposite direction of a cord twist, in S or Z direction.

Claims

1. A high performance textile cord, wherein a residual ply-yarn twist multiplier is greater than 1,000 and less than 4,000 and a residual twist direction of a plurality of ply-yarns in Z or S direction is in an opposite direction of a cord twist, in S or Z direction.

2. The high performance textile cord according to claim 1, wherein the residual ply-yarn twist multiplier of the high performance textile cord is greater than 1,500 and less than 2,500.

3. The high performance textile cord according to claim 1, wherein a total nominal linear density of the high performance textile cord is higher than 500 dtex and less than 8000 dtex.

4. The high performance textile cord according to claim 1, wherein a plurality of cord plies have equal linear density values.

5. The high performance textile cord according to claim 1, wherein a maximum linear density difference between a plurality of plies of the high performance textile cord is less than 10%.

6. The high performance textile cord according to claim 1, wherein a residual twist difference between a plurality of plies of the high performance textile cord is less than 15%.

7. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is nylon 6.6.

8. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is nylon 6.

9. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is nylon 4.6.

10. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is polyethylene terephthalate (PET).

11. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is polyethylene naphthalate (PEN).

12. The high performance textile cord according to claim 1, wherein the plurality of ply-yarns in the high performance textile cord is polyolefin ketone (POK).

13. The high performance textile cord according to claim 1, wherein the high performance textile cord is used as a reinforcement in pneumatic radial and bias tires.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The cord structures and their ply-components according to the invention are illustrated in the accompanying figures, in which:

[0012] FIG. 1 is the comparison of prior art and according to invention S twisted cords, wherein [0013] 1—Prior art S-twisted cord (balanced twisted, Z twist of the ply yarns are equal to the S twist of the cord), and [0014] 2—S-twisted cord according to the invention (unbalanced twisted, Z twist of the ply yarns are greater than the S twist of the cord) with residual Z twist.

[0015] FIG. 2 is the comparison of prior art and according to invention Z twisted cords, wherein [0016] 3—Prior art Z-twisted cord (balanced twisted, S twist of the ply yarns are equal to the Z twist of the cord), and [0017] 4—Z-twisted cord according to the invention (unbalanced twisted, S twist of the ply yarns are greater than the Z twist of the cord) with residual S twist.

[0018] FIG. 3 shows cross-sectional views of 2-ply cords, wherein [0019] 5—2-ply prior art cords with balanced twist having round shape; [0020] 6—and 7—are crescent-shaped cord plies; [0021] 8—cross-section view of the 2-ply cord according to the invention; and [0022] 9—and 10—the plies with residual twist having circular cross-sections in cord according to the invention.

[0023] FIG. 4 shows cross-sectional views of 2-ply cords, wherein [0024] 11—cross-sectional view of the 2-ply cord according to the invention(treated under high tension), and [0025] 12—and 13—the plies with residual twist having oval cross.sections in cord according to the invention.

[0026] FIG. 5 shows cross-sectional views of 3-ply cords, wherein [0027] 14—3-ply prior art cord with balanced twist with round shape; [0028] 15, 16 and 17 triangular shaped plies of prior art cord; [0029] 18. cross-sectional view of the 3-ply cord according to the invention; and [0030] 19—, 20—, and 21—the plies with residual twist having circular cross-sections in cord according to the invention.

[0031] FIG. 6 shows cross-sectional views of 3-ply cords, wherein [0032] 22—cross-sectional view of the 3-ply cord according to the invention(treated under high tension), and [0033] 23—, 24—and 25—the plies with residual twist having oval cross-sections in cord according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] During dipping process of such greige cords having compact and closed filament bundles as plies in cord, adhesive dip solution (RFL) can not penetrate into the depth of cord plies, but be accumulated on the cord surface, which results in low bending stiffness after drying and heat-setting steps, which is important for improved fatigue resistance and breaking strength retention. The residual twist levels in the plies of the textile cords according to the invention are equal to each other but in opposite direction of cord twist (FIG. 1 and FIG. 2).

[0035] The maximum residual twist difference between the cord plies is less than 15%. The plies of the high performance textile cords according to the invention have circular (9 and 10 in FIGS. 3, 19, 20 and 21 in FIG. 5) or oval (12 and 13 in FIGS. 4, 23, 24 and 25 in FIG. 6) cross-sections instead of crescent shaped (6 and 7 in FIGS. 3 and 4) or triangular cross-sections of 2 and 3-ply conventional cords. As can be seen from the FIGS. 3, 4, 5 and 6, the circumference of the high performance cords are much higher than that of the conventional cords. In other words, compared to the conventional cords having the same total cord dtex and ply number, the high performance cords have much higher contact surface (adhesive interface) with rubber matrix in tire. Such an increase in contact surface enables more efficient stress transfer between cord plies and rubber matrix under dynamic conditions leading to the enhanced tire durability.

[0036] The plies of the high performance cords with residual twist, become more closed and compact during heat-setting process due to their thermal contraction in lateral direction which improves ply stability.

[0037] Definitions

[0038] Cord: The reinforcement element formed by twisting together two or more plied yarns

[0039] Cord ply: Basic yarn components of a cord

[0040] Dtex: The gram weight of yarn having 10,000 meter length.

[0041] Linear density: Weight per unit length as g/dtex or g/d(denier)

[0042] Nylon 6.6: Polyhexamethylene adipamide

[0043] Nylon 6: Polycaprolactam

[0044] Nylon 4.6: polytetramethylene adipamide

[0045] PET: Polyethyleneterephthalate

[0046] PEN: polyethylenenaphthalate

[0047] POK: Polyolefinketone

[0048] Residual twist: Resultant twist of the ply yarns of a cord (ply twist-cord twist)

[0049] Total linear density: The sum of the nominal linear densities of 5 the ply yarns of the cord

[0050] Two-ply cord: Cord prepared by twisting together two plied yarns

[0051] Three-ply cord: Cord prepared by twisting together three plied yarns

[0052] Twist: Number of turns per meter (t/m or tpm)

[0053] The residual twist and twist multiplier can be calculated according to following formulas:

Residual twist (tpm)=(ply twist-cord twist)   (1)

Residual Twist Multiplier(R.T.M.)=residual twist in ply yarn(tpm)x√{square root over (ply yarn dtex)}  (2)

TABLE-US-00001 TABLE 1 Residual Twist Multiplier and The Value of Twist in Ply Yarn for 1400 dtex Nylon 6.6 Example Residual (1400 dtex nylon 6.6) PLY YARN Twist appr. twists in ply COMPACTNESS Multiplier yarn (tpm) OPEN  0-200   0-5.0 OPEN TO LOW 200-500  5.0-13.0 LOW TO SUFFICIENT   500-1,500 13-40 SUFFICIENT TO HIGH 1,500-4,500  40-120 HIGH TO VERY HIGH  4500-9,000 120-240 VERY HIGH  9,000-15,000 240-400

[0054] The residual twist multiplier of the ply yarns in the high performance cord according to the invention is greater than 1000 and less than 4000 in opposite direction of the cord twist direction.

[0055] The preferable residual twist multiplier of the ply yarns in the high performance cord according to the invention is greater than 1500 and less than 2500 in opposite direction of the cord twist direction.

[0056] The total linear density of the high performance cord according to the invention is greater than 500 dtex and less than 8000 in opposite direction of the cord twist direction.

[0057] The linear densities of the cord plies according to the invention are equal.

[0058] The maximum linear density difference between the plies of the cord according to the invention is less than 10%.

[0059] The ply yarns in high performance cord according to the invention is comprising nylon 6.6, nylon 6, nylon 4.6, PET, PEN, POK or mixtures thereof.

[0060] The high performance cord according to the invention is used as reinforcement in pneumatic radial and bias tires.