RUBBER COMPOSITION FOR TYRE BODY COMPOUNDS

Abstract

The present invention relates to a cross-linkable rubber composition for body compounds of a tyre, the cross-linkable rubber composition comprising, based upon parts by weight per 100 parts by weight rubber (phr): ≥30 to ≤90 phr of a natural rubber or isoprene rubber or combination thereof, ≥10 to ≤25 phr of a syndiotactic 1, 2-polybutadiene, ≥3 to ≤10 phr of a resin, and a filler, wherein the ratio in phr (parts by weight per 100 parts by weight of rubber) of the syndiotactic 1, 2-polybutadiene to the resin is in the range of ≥1:1 to ≤7:1.

Claims

1. A cross-linkable rubber composition for body compounds of a tyre, the cross-linkable rubber composition comprising, based upon parts by weight per 100 parts by weight rubber (phr): ≥30 to ≤590 phr of a natural rubber or isoprene rubber or combination thereof, ≥10 to ≤525 phr of a syndiotactic 1, 2-polybutadiene, ≥3 to ≤510 phr of a resin, and a filler, wherein, the ratio in parts by weight per 100 parts by weight of the syndiotactic 1,2-polybutadiene to the resin is in the range of ≥1:1 to ≤7:1.

2. The rubber composition according to claim 1, wherein the resin is selected from the class of hydrocarbon thermoplastic resins with melting point above −25° C. such as terpene based resins, alpha methyl styrene, styrene functionalized resins, coumarone indene based resins, C5 resins, C9 resins, or a combination thereof.

3. The rubber composition according to claim 1, wherein the resin is a C10 resin.

4. The rubber composition according to claim 1, wherein the filler is selected from silica, carbon black or combination thereof.

5. The rubber composition according to claim 1 wherein the filler is present in an amount of ≥30 phr to ≤560 phr.

6. The rubber composition according to claim 1, wherein the composition further comprises a second rubber selected from butadiene rubber, styrene butadiene rubber, solution polymerized styrene butadiene rubber or combination thereof.

7. The rubber composition according to claim 1, wherein the second rubber is present in an amount of ≥15 phr to ≤560 phr.

8. The rubber composition according to claim 1, wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin or a combination thereof.

9. A cross-linked rubber composition, obtained by cross-linking a rubber composition according to claim 1.

10. The cross-linked rubber composition according to claim 9, wherein the composition has hardness (measured by DIN-53505) ranging from 55° Sh A to 95° Sh A.

11. The cross-linked rubber composition according to claim 9 with a rebound value at 70° C. (as per ISO 4662) ranging from ≥54% to ≤82%.

12. The cross-linked rubber composition according to claim 9 with a tan delta value at 70° C. (as per DMA double shear 25° C. to 80° C. at 6% strain) ranging from ≥0.04 to ≤0.20.

13. A method of preparing a tyre, comprising the steps of: providing a tyre assembly comprising a cross-linkable rubber composition according to claim 1; and cross-linking at least the cross-linkable rubber composition in the tyre assembly.

14. A tyre comprising at least one body compound, wherein the body compound comprises a cross-linked rubber composition according to claim 9.

15. A body compound of a tyre, wherein the body compound is selected from a cap ply, body ply, belt, apex (dual apex), run flat insert, sidewall, under tread (base) or a combination thereof, wherein the body compound comprises a cross-linked rubber composition according to claim 9.

Description

EXAMPLE 1

[0054] The table below shows the composition C1 and C2 for cap ply in comparison to a reference composition Ref1 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00001 TABLE 1 Components Ref1 C1 C2 NR TSR20 75 75 75 BR 25 — 15 AT400 — 25 10 Processing oil RAE  8 — — CI resin - Novares C10 —  4  4 Filler 1 55 35 35 Filler 2 —  5  5 Tackifier & Homoginizer — — — resins

[0055] The following table shows the results obtained from the cured compositions of table 1:

TABLE-US-00002 TABLE 2 Result Ref1 C1 C2 Hardness (median) °Sh A 55.30 69.50 57.70 Elongation at break % 505.55 555.23 554.60 M300% MPa 11.12 11.25 10.20 Rebound (70° C.) % 71.20 73.00 74.50 Tan (70° C.) 0.1 0.07 0.07

[0056] The results show an increase in the hardness from 55.30 to 69.50 and 57.70 in compositions C.sub.1 and C.sub.2 respectively. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0057] The results further show an increase in rebound at 70 degrees from 71.20 to 73.00 and 74.50 in compositions C.sub.1 and C.sub.2 respectively and a decrease in tan S at 70 degrees from 0.1 to 0.07 in both compositions C1 and C2. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

Example 2

[0058] The table below shows the composition C.sub.3 for body ply in comparison to a reference composition Ref.sub.2 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00003 TABLE 3 Components Ref.sub.2 C.sub.3 NR TSR20 80 80 BR 20 — AT400 — 20 Processing oil RAE  6 — CI resin - Novares C10 —  5 Filler 1 55 40 Tackifier & Homoginizer   1.5 — resins

[0059] The following table shows the results obtained from the cured compositions of table 3:

TABLE-US-00004 TABLE 4 Result Ref.sub.2 C.sub.3 Hardness (median) °Sh A 56.90 67.60 Elongation at break % 479.31 449.96 M300% MPa 12.07 12.99 Rebound (70° C.) % 69.70 75.70 Tan (70° C.) 0.09 0.06

[0060] The results show an increase in the hardness from 56.90 to 67.60 in composition C.sub.3. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0061] The results further show an increase in rebound at 70 degrees from 69.70 to 75.70 in composition C.sub.3 and a decrease in tan δ at 70 degrees from 0.09 to 0.06 in composition C.sub.3. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

Example 3

[0062] The table below shows the compositions C.sub.4 and C.sub.5 respectively for belt in comparison to a reference composition Ref.sub.3 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00005 TABLE 5 Components Ref.sub.3 C.sub.4 C.sub.5 NR TSR20 100  90 85 AT400 — 10 15 Processing oil RAE  3 — — CI resin - Novares C10 —  3  3 Filler 1 48 40 35

[0063] The following table shows the results obtained from the cured compositions of table 5:

TABLE-US-00006 TABLE 6 Result Ref.sub.3 C.sub.4 C.sub.5 Hardness (median) °Sh A 73.70 72.00 73.60 Elongation at break % 375.05 347.19 394.85 M300% MPa 18.71 16.67 16.01 Rebound (70° C.) % 63.50 67.60 69.70 Tan (70° C.) 0.14 0.09 0.08

[0064] The results show an increase in rebound at 70 degrees from 63.50 to 67.60 and 69.70 in compositions C.sub.4 and C.sub.5 respectively and a decrease in tan δ at 70 degrees from 0.14 to 0.09 and 0.08 in compositions C.sub.4 and C.sub.5 respectively. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

[0065] It can also be seen that the hardness of the rubber compositions C.sub.4 and C.sub.5 with respect to Ref.sub.3 is on par.

Example 4

[0066] The table below shows the compositions C.sub.6 and C.sub.7 for apex in comparison to a reference composition Ref.sub.4 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00007 TABLE 7 Components Ref.sub.4 C.sub.6 C.sub.7 NR TSR20 70 70 70 BR 30 20 15 AT400 — 10 15 Processing oil RAE  7 — — CI resin - Novares C10 — 10 10 Filler 1 55 50 50 Tackifier & Homoginizer  6 — — resins

[0067] The following table shows the results obtained from the cured compositions of table 7:

TABLE-US-00008 TABLE 8 Result Ref.sub.4 C.sub.6 C.sub.7 Hardness (median) °Sh A 85.10 89.50 92.10 Elongation at break % 367.59 353.04 362.01 M300% MPa 11.74 13.27 13.02 Rebound (70° C.) % 51.80 54.60 57.40 Tan (70° C.) 0.20 0.17 0.14

[0068] The results show an increase in the hardness from 85.10 to 89.50 and 92.10 in compositions C.sub.6 and C.sub.7 respectively. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0069] The results further show an increase in rebound at 70 degrees from 51.80 to 54.60 and 57.40 in compositions C.sub.6 and C.sub.7 respectively and a decrease in tan δ at 70 degrees from 0.20 to 0.17 and 0.14 in compositions C.sub.6 and C.sub.7 respectively. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

Example 5

[0070] The table below shows the compositions C.sub.5 and C.sub.9 for run flat insert in comparison to a reference composition Ref.sub.5 wherein the the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00009 TABLE 9 Components Ref.sub.5 C.sub.8 C.sub.9 NR TSR20 30 30 30 BR 70 60 65 AT400 10 15 Processing oil RAE 2 — — CI resin - Novares C10 —  3  3 Filler 1 62 50 50 Tackifier & Homoginizer 6.4 — — resins

[0071] The following table shows the results obtained from the cured compositions of table 9:

TABLE-US-00010 TABLE 10 Result Ref.sub.5 C.sub.8 C.sub.9 Hardness (median) °Sh A 72.00 71.40 73.10 Elongation at break % 114.84 110.15 111.77 Rebound (70° C.) % 80.60 81.90 79.70 Tan (70° C.) 0.16 0.04 0.10

[0072] The results show an increase in the hardness from 72.00 to 71.40 and 73.10 in compositions C.sub.5 and C.sub.9 respectively. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0073] The results further show an increase in rebound at 70 degrees from 80.60 to 81.90 and 79.70 in compositions C.sub.8 and C.sub.9 respectively and a decrease in tan δ at 70 degrees from 0.16 to 0.04 and 0.10 in compositions C.sub.8 and C.sub.9 respectively. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

Example 6

[0074] The table below shows the compositions C.sub.10 and C.sub.11 respectively for side wall in comparison to a reference composition Ref.sub.1 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00011 TABLE 11 Components Ref.sub.6 C.sub.10 C.sub.11 NR TSR20 35 35 35 BR 45 35 35 SBR 20 20 20 AT400 10 10 Processing oil RAE  7 — — CI resin - Novares C10 —  7  7 Filler 1 42 35 — Filler 2 — — 35 Tackifier & Homoginizer   3.5 — — resins

[0075] The following table shows the results obtained from the cured compositions of table 11:

TABLE-US-00012 TABLE 12 Result Ref.sub.6 C.sub.10 C.sub.11 Hardness (median) °Sh A 55.90 58.30 55.30 Elongation at break % 414.37 429.03 493.54 M300% MPa 9.82 9.36 7.09 Rebound (70° C.) % 66.10 69.70 73.30 Tan (70° C.) 0.13 0.09 0.07

[0076] The results show an increase in the hardness from 55.90 to 58.30 and 55.30 in compositions C.sub.10 and C.sub.11 respectively. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0077] The results further show an increase in rebound at 70 degrees from 66.10 to 69.70 and 73.30 in compositions C.sub.10 and C.sub.11 respectively and a decrease in tan δ at 70 degrees from 0.13 to 0.09 and 0.07 in compositions C.sub.10 and C.sub.11 respectively. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

Example 7

[0078] The table below shows the compositions C.sub.12 and C.sub.13 for under tread in comparison to a reference composition Ref.sub.7 wherein the composition is free from plasticizing oil, tackifier resin, homogenizing resin.

TABLE-US-00013 TABLE 13 Components Ref.sub.7 C.sub.12 C.sub.13 NR TSR20 100 90 85 AT400 — 10 15 CI resin - Novares C10 —  6  6 Filler 1 44 40 35 Tackifier & Homoginizer 6.5 — — resins

[0079] The following table shows the results obtained from the cured compositions of table 13:

TABLE-US-00014 TABLE 14 Result Ref.sub.7 C.sub.12 C.sub.13 Hardness (median) °Sh A 59.20 62.80 64.70 Elongation at break % 415.79 455.21 481.95 M300% MPa 15.92 13.58 12.13 Rebound (70° C.) % 70.30 71.50 72.70 Tan (70° C.) 0.09 0.08 0.07

[0080] The results show an increase in the hardness from 59.20 to 62.80 and 64.70 in compositions C.sub.12 and C.sub.13 respectively. The increase in hardness is a well-known indicator of better stiffness in the tyre industry.

[0081] The results further show an increase in rebound at 70 degrees from 70.30 to 71.50 and 72.70 in compositions C.sub.12 and C.sub.13 respectively and a decrease in tan δ at 70 degrees from 0.09 to 0.08 and 0.07 in compositions C.sub.12 and C.sub.13 respectively. The increase in rebound and decrease in tan δ are well known indicators of improvement in hysteresis in the tyre industry.

[0082] Such cross-linked rubber compositions are particularly usable for manufacturing tyre body compounds.