Reinforcement materials, elastomeric compositions and tyres for vehicles wheels comprising the same

Abstract

The present invention relates to new elastomeric materials for the production of tyres for vehicle wheels with good mechanical properties, in particular high moduli associated with low hysteresis values, including new reinforcement materials. Said reinforcement materials are obtainable by derivatising silica—in-situ during the mixing of the elastomeric composition, or previously—with special silanising agents (A) and silsesquioxanes (B), both substituted with reactive alkenyl functionalities.

Claims

1. A process for preparing derivatised silica (SIL-A-B) comprising: providing silanised silica (SIL-A), wherein the silanised silica (SIL-A) is made by a process comprising: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein X1 is a group —R3-C(Wa)═C(R4)R4, X2 is a group —R3-C(R4)=C(Wa)R4, and X3 is a group —R3-Wb-C(R4)=C(R4)R4, wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above, placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00007## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, and groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound of (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

2. The process according to claim 1, wherein the R3 of group X is chosen from unsaturated alkylene groups.

3. The process according to claim 1, wherein an acid catalyst is placed in the first reaction medium in contact with the silica (C) and the silanising agent (A).

4. The process according to claim 1, wherein the at least one silanising agent is a compound of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2 and OR2, and R2 is chosen from linear and branched alkyl groups with 1 to 3 carbon atoms; group X is a reactive alkenyl group X3 as defined above, wherein R3 is an alkylene group with 2 to 5 carbon atoms, Wb is a group —O—CO— and R4, the same or different from each other, are chosen from H and alkyl groups with 1 to 3 carbon atoms.

5. The process according to claim 1, wherein the compound of formula (B) is a closed cage silsesquioxane of formula (B1)
(RSiO.sub.1,5).sub.n  (B1) wherein n is an even number ranging from 6 to 12, and all groups R are reactive groups X3 as defined above, wherein R3 is an alkylene group with 2 to 5 carbon atoms, Wb is a group —O—CO— and R4, the same or different from each other, are chosen from H and alkyl groups with 1 to 3 carbon atoms, or all groups R are reactive groups X1 as defined above, wherein R3 is absent, and Wa and R4 are all H.

6. The process according to claim 1, wherein the silica (C) is an amorphous precipitated silica.

7. The process according to claim 1, wherein the silanising agent (A) is used in a weight ratio, with respect to silica (C), ranging from 0.05:1 to 1:1.

8. The process according to claim 1, wherein when preparing the silanised silica (SIL-A), an acid catalyst is used.

9. The process according to claim 1, wherein the at least one compound of formula (B) is used in a weight ratio, with respect to the silanised silica (SIL-A), ranging from 0.03:1 to 1:1.

10. The process according to claim 1, wherein the radical initiator (D) is chosen from the class of organic peroxide initiators or from the class of azo compounds.

11. The process according to claim 1, wherein the first and the second reaction mediums comprise an organic solvent chosen from toluene and one or more alcohols.

12. The process according to claim 11, wherein the organic solvent is mixed with water.

13. A derivatised silica (SIL-A-B) made by a process comprising: providing silanised silica (SIL-A), wherein the silanised silica (SIL-A) is made by a process comprising: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein X1 is a group —R3-C(Wa)═C(R4)R4, X2 is a group —R3-C(R4)=C(Wa)R4, and X3 is a group —R3-Wb-C(R4)=C(R4)R4, wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above; placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00008## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, and groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound of (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

14. The derivatised silica (SIL-A-B) according to claim 13, wherein the at least one compound of formula (B) is present in an amount, expressed as a percentage by weight with respect to the starting silica weight (C), equal to at least 3%.

15. An elastomeric composition comprising: at least 100 phr of at least one solid diene elastomeric polymer (E), and at least 3 phr of a derivatised silica (SIL-A-B) made by a process comprising: providing silanised silica (SIL-A), the silanised silica made by a process comprising: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein  X1 is a group —R3-C(Wa)═C(R4)R4,  X2 is a group —R3-C(R4)=C(Wa)R4, and  X3 is a group —R3-Wb-C(R4)=C(R4)R4,  wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, 303R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above; placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00009## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, and groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound of (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

16. An elastomeric composition comprising: at least 100 phr of at least one solid diene elastomeric polymer (E); at least 5 phr of silica (C); at least 0.3 phr of a silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein X1 is a group —R3-C(Wa)═C(R4)R4, X2 is a group —R3-C(R4)=C(Wa)R4, and X3 is a group —R3-Wb-C(R4)=C(R4)R4, wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above; and at least 0.5 phr of a compound of formula (B), wherein formula (B) is chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00010## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, and groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above.

17. The elastomeric composition according to claim 16, comprising: at least 100 phr of at least one solid diene elastomeric polymer (E), 5 to 60 phr of silica (C), 0.5 to 10 phr of silanising agent of formula (A), and 1 to 30 phr of at least one compound of formula (B).

18. A vulcanisable elastomeric composition for a tyre for vehicle wheels, comprising: at least 0.1 phr of at least one vulcanising agent (F); and an elastomeric composition comprising at least 100 phr of at least one solid diene elastomeric polymer (E) and at least 3 phr of a derivatised silica (SIL-A-B) made by a process comprising: providing silanised silica (SIL-A), the silanised silica made by a process comprising: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein  X1 is a group —R3-C(Wa)═C(R4)R4,  X2 is a group —R3-C(R4)=C(Wa)R4, and  X3 is a group —R3-Wb-C(R4)=C(R4)R4,  wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and R4, the same or different from each other, are H or are chosen from the groups R2 defined above; placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00011## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

19. A tyre component for vehicle wheels, either green or at least partially vulcanised, comprising a vulcanisable elastomeric composition comprising: at least 0.1 phr of at least one vulcanising agent (F); and an elastomeric composition comprising at least 100 phr of at least one solid diene elastomeric polymer (E), and at least 3 phr of a derivatised silica (SIL-A-B) made by a process comprising: providing silanised silica (SIL-A), the silanised silica made by a process comprising: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein  X1 is a group —R3-C(Wa)═C(R4)R4,  X2 is a group —R3-C(R4)=C(Wa)R4, and  X3 is a group —R3-Wb-C(R4)=C(R4)R4,  wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above; placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof,
(RSiO.sub.1,5).sub.n (RSiO.sub.1,5).sub.x[RSi(OR4)O].sub.y [RSi(OH)O].sub.3—4
(B1) (B2) (B3) wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound of (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

20. The tyre component according to claim 19, wherein the component is chosen from tread, carcass structure, belt structure, under-layer, bead protection layers, sidewall, sidewall insert, mini-sidewall, under-liner, rubber layers, bead filler, and sheet.

21. A tyre for vehicle wheels comprising at least one tyre component, either green or at least partially vulcanized, chosen from tread, carcass structure, belt structure, under-layer, bead protection layers, sidewall, sidewall insert, mini-sidewall, under-liner, rubber layers, bead filler, and sheet, wherein the tyre component comprises a vulcanisable elastomeric composition comprising: at least 0.1 phr of at least one vulcanising agent (F); and an elastomeric composition comprising at least 100 phr of at least one solid diene elastomeric polymer (E), and at least 3 phr of a derivatised silica (SIL-A-B) made by a process comprising: providing silanised silica (SIL-A), the silanised silica being obtainable according to a process which preferably comprises: providing silica (C), providing at least one silanising agent of formula (A),
(R1).sub.3Si—X  (A) wherein R1, the same or different from each other, are chosen from R2, OR2, OSi(OR2).sub.3, OH, halogen, and group X, provided that at least one R1 is equal to OR2, OSi(OR2).sub.3, OH, or halogen; R2, the same or different from each other, are chosen from linear and branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkylaryl groups with 7 to 20 carbon atoms, and aryl groups with 6 to 20 carbon atoms; group X is a reactive alkenyl group chosen from X1, X2, and X3, wherein  X1 is a group —R3-C(Wa)═C(R4)R4,  X2 is a group —R3-C(R4)=C(Wa)R4, and  X3 is a group —R3-Wb-C(R4)=C(R4)R4,  wherein  R3 is absent or is chosen from linear and branched alkylene groups with 1 to 10 carbon atoms,  Wa is H or an electron-attractor group chosen from COOR4, CONR4R4, NO.sub.2, CN, COR4, SO.sub.3R4, NR4R4, and halogen,  Wb is a group chosen from —O—CO—, —COO—, —NR4-CO—, —CO—NR4-, —SO—, —SO.sub.2—, and —CO—, and  R4, the same or different from each other, are H or are chosen from the groups R2 defined above; placing the silica (C) and the silanising agent (A) in contact in a first reaction medium, allowing the silica (C) and the silanising agent (A) to react until the silanised silica (SIL-A) is obtained, and separating the silanised silica (SIL-A) from the first reaction medium; placing the silanised silica (SIL-A) in contact, in a second reaction medium, with at least one compound of formula (B) chosen from the silsesquioxanes of formula (B1), (B2), the compounds of formula (B3), and mixtures thereof, ##STR00012## wherein n is an even number ranging from 4 to 24, x is an integer ranging from 3 to 23, y is an integer ranging from 1 to 6, and x+y≤24, groups R, the same or different from each other, are chosen from R2 and X, provided that at least one of groups R is a group X, wherein R2, R4 and X are as defined above; adding at least one radical initiator (D) to the second reaction medium; and allowing the silanised silica (SIL-A), the at least one compound of (B), and the at least one radical initiator (D) to react until a derivatised silica (SIL-A-B) is obtained.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a radial half-section of a tyre for vehicle wheels.

(2) FIG. 2 shows the graphs of moduli G′ with increasing strain of samples of vulcanised elastomeric compositions of the invention comprising derivatised silica (SIL-A-B) with different contents of B (Ex. 6b-6d) with respect to a comparative sample comprising silanised silica alone (SIL-A) (Ex, 6a).

(3) FIG. 3 shows the graphs of moduli G′ with increasing strain of samples of vulcanised elastomeric compositions with &CBS (Ex. 7a, 7b and 7c).

(4) FIGS. 4a and 4b show the graphs of moduli G′ and of hysteresis of the samples of vulcanised elastomeric compositions of examples 8a (comparative) and 8b (invention), respectively.

(5) FIG. 5 is the spectrum .sup.29Si-NMR of a sample of derivatised silica (SIL-A-B) according to the present invention compared to the spectrum of a sample of silanised silica (SIL-A).

(6) FIG. 6 is the spectrum .sup.13C-NMR of a sample of derivatised silica (SIL-A-B) according to the present invention compared to the spectrum of a sample of silanised silica (SIL-A).

DESCRIPTION OF EXAMPLES OF THE INVENTION

(7) The description of some examples of the invention is given hereinafter by way of non-limiting indication.

(8) FIG. 1 shows a radial half-section of a tyre for vehicle wheels according to the invention.

(9) In FIG. 1, “a” indicates an axial direction and “X” indicates a radial direction, in particular X-X indicates the outline of the equatorial plane. For simplicity, FIG. 1 shows only a portion of the tyre, the remaining portion not shown being identical and arranged symmetrically with respect to the equatorial plane “X-X”.

(10) Tyre 100 for four-wheeled vehicles comprises at least one carcass structure, comprising at least one carcass layer 101 having respectively opposite end flaps engaged with respective annular anchoring structures 102, referred to as bead cores, possibly associated to a bead filler 104.

(11) The tyre area comprising the bead core 102 and the filler 104 forms a bead structure 103 intended for anchoring the tyre onto a corresponding mounting rim, not shown.

(12) The carcass structure is usually of radial type, i.e. the reinforcement elements of the at least one carcass layer 101 lie on planes comprising the rotational axis of the tyre and substantially perpendicular to the equatorial plane of the tyre. Said reinforcement elements generally consist of textile cords, such as rayon, nylon, polyester (for example polyethylene naphthalate, PEN). Each bead structure is associated to the carcass structure by folding back of the opposite lateral edges of the at least one carcass layer 101 around the annular anchoring structure 102 so as to form the so-called carcass flaps 101a as shown in FIG. 1.

(13) In one embodiment, the coupling between the carcass structure and the bead structure can be provided by a second carcass layer (not shown in FIG. 1) applied in an axially outer position with respect to the first carcass layer.

(14) An anti-abrasive strip 105 is arranged in an outer position of each bead structure 103.

(15) The carcass structure is associated to a belt structure 106 comprising one or more belt layers 106a, 106b placed in radial superposition with respect to one another and with respect to the carcass layer, having typically textile and/or metallic reinforcement cords incorporated within a layer of vulcanised elastomeric composition.

(16) Such reinforcement cords may have crossed orientation with respect to a direction of circumferential development of tyre 100. By “circumferential” direction it is meant a direction generally facing in the direction of rotation of the tyre.

(17) At least one zero-degree reinforcement layer 106c, commonly known as a “0° belt”, may be applied in a radially outermost position to the belt layers 106a, 106b, which generally incorporates a plurality of elongated reinforcement elements, typically metallic or textile cords, oriented in a substantially circumferential direction, thus forming an angle of a few degrees (such as an angle of between about 0° and 6°) with respect to a direction parallel to the equatorial plane of the tyre, and coated with vulcanised elastomeric composition.

(18) A tread band 109 of vulcanised elastomeric composition is applied in a position radially outer to the belt structure 106.

(19) Moreover, respective sidewalls 108 of vulcanised elastomeric composition are applied in an axially outer position on the lateral surfaces of the carcass structure, each extending from one of the lateral edges of tread 109 at the respective bead structure 103.

(20) In a radially outer position, the tread band 109 has a rolling surface 109a intended to come in contact with the ground. Circumferential grooves, which are connected by transverse notches (not shown in FIG. 1) so as to define a plurality of blocks of various shapes and sizes distributed over the rolling surface 109a, are generally made on this surface 109a, which for simplicity is represented smooth in FIG. 1,

(21) An under-layer 111 of vulcanised elastomeric composition can be arranged between the belt structure 106 and the tread band 109.

(22) A strip consisting of elastomeric composition 110, commonly known as “mini-sidewall”, of vulcanised elastomeric composition can optionally be provided in the connecting zone between sidewalls 108 and the tread band 109, this mini-sidewall generally being obtained by co-extrusion with the tread band 109 and allowing an improvement of the mechanical interaction between the tread band 109 and sidewalls 108. Preferably, the end portion of sidewall 108 directly covers the lateral edge of the tread band 109.

(23) In the case of tubeless tyres, a rubber layer 112, generally known as “liner”, which provides the necessary impermeability to the inflation air of the tyre, can also be provided in a radially inner position with respect to the carcass layer 101.

(24) The rigidity of the tyre sidewall 108 can be improved by providing the bead structure 103 with a reinforcement layer 120 generally known as “flipper” or additional strip-like insert.

(25) Flipper 120 is a reinforcement layer which is wound around the respective bead core 102 and the bead filler 104 so as to at least partially surround them, said reinforcement layer being arranged between the at least one carcass layer 101 and the bead structure 103. Usually, the flipper is in contact with said at least one carcass layer 101 and said bead structure 103.

(26) Flipper 120 typically comprises a plurality of textile cords incorporated within a layer of vulcanised elastomeric composition.

(27) The bead structure 103 of the tyre may comprise a further protective layer which is generally known by the term of “chafer” 121 or protective strip and which has the function of increasing the rigidity and integrity of the bead structure 103.

(28) Chafer 121 usually comprises a plurality of cords incorporated within a layer of vulcanised elastomeric composition. Such cords are generally made of textile materials (such as aramide or rayon) or metal materials (such as steel cords).

(29) A layer or sheet of elastomeric composition can be arranged between the belt structure and the carcass structure. The layer can have a uniform thickness. Alternatively, the layer may have a variable thickness in the axial direction. For example, the layer may have a greater thickness close to its axially outer edges with respect to the central (crown) zone.

(30) Advantageously, the layer or sheet can extend on a surface substantially corresponding to the extension surface of said belt structure.

(31) In a preferred embodiment, a layer or sheet of elastomeric composition as described above can be placed between said belt structure and said tread band, said additional layer or sheet extending preferably on a surface substantially corresponding to the extension surface of said belt structure.

(32) The vulcanisable elastomeric composition according to the present invention can be advantageously incorporated in one or more of the components of the tyre selected from the belt structure, carcass structure, tread band, under-layer, sidewall, mini-sidewall, sidewall insert, bead, flipper, chafer, sheet and bead protective layers.

(33) The elastomeric composition of one or more of the components mentioned above according to the present invention may comprise at least:

(34) 100 phr of at least one solid diene elastomeric polymer (E),

(35) at least 3 phr of a derivatised silica (SIL-A-B) according to the second aspect of the invention.

(36) The elastomeric composition of one or more of the components mentioned above according to the present invention may comprise at least

(37) 100 phr of at least one solid diene elastomeric polymer (E),

(38) at least 5 phr of silica (C),

(39) at least 0.3 phr of a silanising agent of formula (R1).sub.3Si—X (A), and

(40) at least 0.5 phr of a compound of formula (B) as defined above.

(41) The above elastomeric compositions of one or more tyre components mentioned above according to the present invention further comprise at least: at least 0.1 phr of at least one vulcanising agent (F), and preferably 0.5 to 10 phr of at least one activating agent for the vulcanisation (F1); and/or 0.1 to 10 phr of at least one accelerant for the vulcanisation (F2), and/or 0.05 to 2 phr of at least one retardant for the vulcanisation (F3).

(42) According to an embodiment not shown, the tyre may be a tyre for motorcycle wheels which is typically a tyre that has a straight section featuring a high tread camber.

(43) According to an embodiment not shown, the tyre may be a tyre for heavy transport vehicle wheels, such as trucks, buses, trailers, vans, and in general for vehicles in which the tyre is subjected to a high load.

(44) Preferably, such a tyre is adapted to be mounted on wheel rims having a diameter equal to or greater than 17.5 inches for directional or trailer wheels.

EXAMPLES

(45) Where not indicated otherwise, in the present experimental part the components of the compositions are expressed in phr (parts per hundreds of rubber).

(46) The following Tables 1 and 2 summarise comparative experiments and according to the invention for preparing the reinforcement materials (Ex. 1-3), of the elastomeric materials comprising them (Examples 4b, 6b, 6c, 6d and 7c) (previously derivatised silica) and of the elastomeric materials prepared by mixing “in-situ” all ingredients (Examples 4a, 5a, 5b, 6a, 7a, 7b, 8a, 8b, 9a, 9b and 9c):

(47) TABLE-US-00002 TABLE 1 reinforcement materials p/w MAPOSS with Reinforcement respect to Ex. Reagents material silica 1 Comp. silica and TMMS (A) SIL-TMMS (SIL-A) 2 Comp. silica and TEMS (A) SIL-TEMS (SIL-A) 3a Inv. SIL-TMMS (SIL-A) and SIL-TMMS- 10 p/w MAPOSS (B) MAPOSS10 (SIL-A-B) 3b Inv. SIL-TMMS (SIL-A) and SIL-TMMS-  5 p/w MAPOSS (B) MAPOSS5 (SIL-A-B) 3c Inv. SIL-TMMS (SIL-A) and SIL-TMMS-  3 p/w MAPOSS (B) MAPOSS3 (SIL-A-B) 3d Inv. SIL-TEMS (SIL-A) and SIL-TEMS- 10 p/w MAPOSS (B) MAPOSS10 (SIL-A-B)
wherein SIL: silica; TEMS: 3-(triethoxysilyl)propyl methacrylate; TMMS: 3-(trimethoxysilyl)propyl methacrylate; MAPOSS: Octamethacrylpropyl silsesquioxane p/w: parts by weight.

(48) TABLE-US-00003 TABLE 2 elastomeric materials including the reinforcement materials Preparation Type of Specific of the reinforcement reinforcement reinforcement Elastomer Vulcanising Ex. Comp./Inv. material material material (E) agent (F) 4a Comp SIL + A SIL + TMMS In-situ SBR 2525 DCP 4b Inv. SIL − A − B SIL − TMMS − Preformed SBR 2525 DCP MAPOSS10 Ex. 3a 5a Comp SIL + A SIL + TMMS In-situ SBR 2525 DCP 5b Comp SIL + B SIL + MAPOSS In-situ SBR 2525 DCP 5c Inv. SIL + A + B SIL + TMMS + In-situ SBR 2525 DCP MAPOSS 6a Comp SIL + A SIL + TMMS In-situ SLR 4630 DCP 6b Inv. SIL − A − B SIL − TMMS − Preformed SLR 4630 DCP MAPOSS3 Ex. 3c 6c Inv. SIL − A − B SIL − TMMS − Preformed SLR 4630 DCP MAPOSS5 Ex. 3b 6d Inv. SIL − A − B SIL − TMMS − Preformed SLR 4630 DCP MAPOSS10 Ex. 3a 7a Comp SIL + A SIL + TMMS In-situ SLR 4630 sulphur/CBS 7b Inv. SIL + A + B SIL + TMMS + In-situ SLR 4630 sulphur/CBS MAPOSS 7c Inv. SIL − A − B SIL − TMMS − Preformed SLR 4630 sulphur/CBS MAPOSS10 Ex. 3a 8a Comp SIL + A + B SIL + TESPT + In-situ SLR 4630 DCP MAPOSS 8b Inv. SIL + A + B SIL + TEMS + In-situ SLR 4630 DCP MAPOSS 9a Comp SIL + A SIL + TEMS In-situ IR/BR Luperox 101 9b Comp SIL + A SIL + TEMS In-situ IR/BR Luperox 101 9c Inv. SIL + A + B SIL + TEMS + In-situ IR/BR Luperox 101 MAPOSS
Key: Comp.: comparative example, Inv.: example according to the invention, SIL silica, A: silanising agent, B: silsesquioxane, TEMS: 3-(triethoxysilyl)propyl methacrylate; 3-(trimethoxysilyl)propyl methacrylate, SIL-TMMS-MAPOSS3, SIL-TMMS-MAPOSS5, SIL-TMMS-MAPOSS10, SIL-TEMS-MAPOSS10 are the inventive products of silanised silica derivatised with POSS, SLR 4630 is SBR with high vinyl by Styron, SBR 2525 is SBR with low vinyl by Lanxess, IR is synthetic polyisoprene, BR is high cis neodymium polybutadiene, DCP dicumylperoxide, Luperox 101 is 2,5-bis(t-butyl peroxy)-2,5-dimethyl hexane, CBS is cyclohexylbenzothiazolsulphenamide, primary accelerant.

(49) In the present description, unless stated otherwise, the sign “+” between components means that the same are added separately to the elastomer and made to react in-situ during mixing. For example, the addition of silica and MAPOSS to the elastomeric material may be referred to as SIL+MAPOSS.

(50) Instead, the symbol “-” between two components is generally meant to indicate that such components have pre-reacted with each other, such as SIL-TEMS is the product obtained by reaction of silica and silanising agent TEMS as described in example 2.

Example 1

(51) Preparation of Silanised Silica (SIL-A) by Reaction of Silica (C) with the Silanising Agent TMMS (A) in the Absence of Acid Catalyst

(52) About 15 g of trimethoxypropylmethacrylsilane (TMMS distributed by Sigma Aldrich) were dispersed in 200 ml of a water/methanol solution (96/4 p/w) and kept under stirring at room temperature for 15 minutes. 50 g of silica (Zeosil 1165 by Rhodia) were added and left under vigorous stirring for 48 h at room temperature. The solvent is evaporated at the rotavapor and the sample is dried in an oven at 120° C. overnight. About 60 g of silanised silica (SIL-TMMS) were obtained.

Example 2

(53) Preparation of Silanised Silica (SIL-A) by Reaction of Silica (C) with the Silanising Agent TEMS (A) in the Presence of Acid Catalyst

(54) About 25 g of triethoxypropylmethacrylsilane (TEMS distributed by GELEST) were dispersed in 200 ml of toluene and kept under stirring at room temperature for 15 minutes. 50 g of silica and 5.0 ml of trifluoroacetic acid were added and left under vigorous stirring for 48 h at room temperature. The solvent was evaporated at the rotavapor and the sample is dried in an oven at 120° C. overnight. About 65 g of silanised silica (SIL-TEMS) were obtained.

Example 3

(55) Derivatisation of Silanised Silica (SIL-A) with MAPOSS (B)

Example 3a

(56) 1.5 g of octamethacrylpropyl silsesquioxane (Hybrid Plastic MA0735, MAPOSS for brevity) were suspended in 150 ml of toluene at room temperature and left under stirring 15 minutes. To the suspension thus obtained were added 15 g of Silica-TMMS prepared as described in Example 1. To the suspension heated under reflux and under stirring were added 0.03 g of dicumylperoxide (DCP) and the suspension was kept under stirring at the same temperature for 3 h. The solvent was removed at the rotavapor and the sample is dried in an oven at 120° C. overnight. About 16 g of derivatised silica were obtained (SIL-TMMS-MAPOSS10 where 10 indicates the parts by weight of MAPOSS with respect to the weight of silica).

(57) The same procedure of Example 3a was repeated but using 0.75 g and 0.45 g of MAPOSS, obtaining about 15 g of SIL-TMMS-MAPOSS5 (Example 3b) and about 14 g of SIL-TMMS-MAPOSS3 (Example 3c), respectively.

(58) Finally, the same procedure of example 3a was repeated but using the silanised silica SIL-TEMS obtained as described in example 2, obtaining about 16 g of SIL-TEMS-MAPOSS10 (Example 3d), substantially identical to the material of example 3a, since the ethoxy groups of silane reacted with silica and were removed as volatile ethanol.

(59) A sample of silanised silica (SIL-TMMS Ex. 1) and a sample of derivatised silica according to the invention (SIL-TMMS-MAPOSS10 Ex. 3d) were analysed by NMR spectroscopy (.sup.29Si and .sup.13C),

(60) As can be seen in FIG. 5, the NMR spectrum of .sup.29Si confirms the incorporation of silsesquioxane in the derivatised silica SIL-A-B. In fact, in addition to signals Q.sup.2Q.sup.3 and Q.sup.4 present in both spectra, attributable to silica, in the spectrum of derivatised silica SIL-A-B peaks T1 and T3 are clearly visible, associated to the cage structure of agent (B).

(61) As can be seen in FIG. 6, the NMR spectrum of .sup.13C for sample SIL-A-B shows between 130 and 140 ppm the presence of signals of the double bonds of the methacrylic group.

(62) This confirms that also after the synthesis reaction of SIL-A-B there are still reactive groups deriving from the silanising agent and from silsesquioxane. The Applicant believes that these reactive groups, in the presence of a radical initiator, would be capable of effectively interacting with the elastomer, leading to optimal cross-linking.

Preparation of Elastomeric Materials Including the Reinforcement Materials and their Properties

(63) Samples of vulcanised elastomeric materials were prepared to evaluate the effect of the incorporation of the new reinforcement materials of the invention with respect to traditional fillers or ones described in the literature, in particular on the properties of moduli and hysteresis.

(64) The elastomeric materials were prepared according to this general procedure:

(65) The elastomers were loaded into an internal mixer (Brabender or Banbury)

(66) The silica and the possible reagents for the “in-situ” derivatisation thereof or the silica already derivatised were added to the mixer and mixed for about 5 minutes.

(67) Stearic acid, 6PPD and ZnO were added, continuing the mixing. As soon as the temperature reached 145° C.±5° C., the elastomeric material was unloaded.

(68) The material from the previous step was introduced in an internal mixer (Brabender or Banbury), DCP, Luperox 101 or the CBS/sulphur system were added and the mixing was carried out for 3 minutes at 90° C.

Evaluation of the Elastomeric Materials

(69) Properties of Non-Vulcanised Materials

(70) The vulcanisable (green) elastomeric materials of Examples 9a, 9b and 9c were subjected to the following evaluations:

(71) MDR rheometric analysis (according to ISO 6502): a rheometer Alpha Technologies type MDR2000 was used. The tests were carried out at 170° C. for 20 minutes at an oscillation frequency of 1.66 Hz (100 oscillations per minute) and an oscillation amplitude of ±0.5°, measuring the time necessary to achieve an increase of two rheometric units (TS2) and the time necessary to achieve 60% (T60) and 90% (T90), respectively, of the final torque value (Mf). The maximum torque value MH and the minimum torque value ML were also measured.

(72) The results of these analyses on the samples of examples 9a-9c are shown in Table 8.

(73) Properties of Vulcanised Materials

(74) The elastomeric materials of Examples 9a, 9b, 9c were subjected to the following evaluations after vulcanisation:

(75) The static mechanical properties were measured at 23° C. according to the ISO 37:2005 standard.

(76) In particular, the load at different levels of elongation (100% and 300%, named CA1 and CA3), the load at break CR were measured on samples of the elastomeric materials mentioned above, vulcanised at 170° C. for 15 minutes.

(77) The tensile tests were carried out on straight axis Dumbell specimens.

(78) The vulcanised elastomeric materials of Examples 4 to 9 were subjected to the following evaluations:

(79) The dynamic mechanical properties were measured using an Instron dynamic device in traction-mode according to the following methods.

(80) A sample of the elastomeric materials of the Examples vulcanised at 170° C. for 15 minutes having a cylindrical shape (length=25 mm; diameter=14 mm), subjected to pre-load compression up to 25% of the longitudinal deformation with respect to the initial length and maintained at the predetermined temperature (equal to −10° C., 0° C., 23° C. or 70° C.) for the whole duration of the test, was subjected to a dynamic sinusoidal strain having an amplitude of ±3.5% with respect to the length under pre-load, with a frequency of 100 Hz.

(81) The dynamic mechanical shear properties were evaluated for the samples of Examples 4 to 9 using a Monsanto R.P.A. 2000 according to the following method: cylindrical test specimens with weights from 4.5 to 5.5 g were obtained by punching the vulcanisable elastomeric composition being tested.

(82) These samples were vulcanised in the “RPA” instrument at 170° C. for 10 minutes or 15 minutes depending on the vulcanisation kinetics and were subjected to dynamic measurement of the dynamic elastic shear modulus (G′) at 70° C., frequency of 10 Hz, deformation between 0.1% and 10%, and Tan delta (hysteresis or dissipation factor, Tan d), calculated as the ratio between viscous modulus (G″) and elastic modulus (G′) measured in the same conditions (70° C., 10 Hz).

(83) The Payne effect was assessed in absolute terms through the difference between moduli (G′) and at 10% and 0.5%, and in relative terms as a percentage variation between 10% and 0.5% with respect to modulus G′ at 9%.

(84) The following Tables list the recipes for preparing the elastomeric materials according to the invention and comparative and the results of the analyses described above conducted on those samples.

Example 4

(85) The following Table 3 shows the components of the elastomeric materials of the comparative Example 4a, of Example 4b according to the invention and of a conventional reference bead elastomeric material—where silica is traditionally not used as it is unsuitable to impart such high moduli necessary for this particular application—and their values of G′, dG′ and tan Delta were measured, according to the above methods, on samples vulcanised at 170° C. for 10 minutes:

(86) TABLE-US-00004 TABLE 3 Ex. 4b Ex. 4a Invention Conventional Comparative SIL-TMMS- bead SIL + TMMS MAPOSS material Component (amount in phr) SBR 2525 100 100 IR 100 Silica 1165 30 TMMS 3 SIL-TMMS-MAPOSS10 33 N375 70 Stearic acid 2 2 2 6PPD 2 2 2 ZnO 3.5 3.5 8 Reactive phenolic resin 15 DCP 2 2 HMMM 65% 6 TBBS 1 sulphur 7 Properties dG′(0.5-10) [MPa] 0.59 1.13 13.5 dG′(0.5-10)/G′(9) 42% 17% 211% G′ (9%) [MPa] 1.39 6.52 6.41 Tan d (9%) [—] 0.098 0.067 0.301 G′ (3%) [MPa] 1.42 6.93 8.52 Tan d (3%) [—] 0.113 0.056 0.371
Key: SBR 2525: containing 25% of vinyl on total monomers; IR: Synthetic polyisoprene by Nizhnekamskneftekhim; Silica 1165: Zeosil 1165 by Rhodia; TMMS: trimethoxypropyl methacrylsilane Sigma Aldrich; SIL-TMMS-MAPOSS10: derivatised silica prepared in Example 3°; N375: carbon black by Birla Carbon; Stearic acid: Stearina TP8 by Undesa; 6PPD: N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine Santoflex-6 PPD by Eastman; Reactive phenolic resin: DUREZ 12686 by Sumitomo Bakelite Europe NV; ZnO: zinc oxide by Zincol Ossidi; DCP: dicumyl peroxide by Arkema; 65% HMMM: hexamethoxymethylmelamine (65%) on an inert support, Cyrez 964 P.C.; TBBS: N-tert-butyl-2-benzothiazilsulphenamide, Vulkacit® NZ/EGC, Lanxess; Sulphur: Redball Superfine, International Sulphur Inc; G′ (3%) and G′ (9%) represent the shear moduli measured at 70° C., 10 Hz at 3% and 9% of dynamic deformation; dG′ (0.5-10) indicates the difference between the shear modulus at 0.5% and 10% of dynamic deformation measured at 10 Hz, 70° C. with a Monsanto R.P.A. 2000; Tan d (Tan delta) represents the value of the ratio between G′ and G″ recorded at 10 Hz, 70° C. at a deformation of 3% and 9%; dG′ (0.5-10)/G′(9) is the dG′ value (0.5-10) expressed as a percentage with respect to the dynamic shear modulus value measured at 9%, an index of the extent of the Payne effect with respect to the rigidity of the blend.

(87) As can be seen from the results of the analyses reported in Table 3, the derivatised silica according to the invention imparts a surprisingly high modulus to the elastomeric material (Ex. 4b) with respect to the comparative material (Ex. 4a)—in fact, the G′ modulus increases by about 5 times—and even more unexpectedly a significant reduction in hysteresis as evidenced by a decrease of tan d by a factor of about 1.5-2.

(88) Considering the conventional bead material, it can be seen that it has a dynamic modulus at 9%, in line with respect to the sample of the invention of Ex. 4b. This modulus value, obtained by using more than twice the filler (70 phr carbon black vs. 33 phr SIL-TEMS-MAPOSS10), much more vulcanising and hardening phenol-formaldehyde resins, is however to the detriment of the hysteresis of the material itself that is significantly high with respect to that of the sample according to the invention of Ex. 4b (0.301 vs 0.067).

(89) With the reinforcement materials of the invention it was possible to impart high moduli and low hysteresis with the use of smaller amounts of filler and in the absence of phenol-formaldehyde hardening resins. This balance of properties appears to be particularly interesting and predictive for tyre applications where white fillers are already used, such as tread, under-layer, sidewall or sidewall insert, which require low hysteresis.

(90) In addition, the derivatised silica according to the invention, which imparts a considerable reinforcement to the materials that incorporate it, surprisingly allows expanding the application possibilities, namely to use these fillers in small amounts, even in very demanding applications, such as for example bead filler materials, bead protective layers and rigid under-layers, where traditionally large amounts of filler and/or phenol-formaldehyde hardening resins are used.

(91) Considering the high efficacy of the present fillers in raising the modulus values, the man skilled in the art will be able to modulate ad hoc the final effect on the material depending on the application in the tyre, reducing or increasing the incorporated amount thereof, with the undoubted advantage of maintaining the hysteresis acceptable or advantageously reduced.

Example 5

(92) In this example, elastomeric materials according to the invention (Ex. 5c) and comparative (Ex. 5a and 5b) were prepared by adding the silica (C), the silanising reagent (A) (TMMS) and/or the silsesquioxane (B) (MAPOSS) during mixing, without any pre-treatment of the silica (preparation “in-situ”).

(93) The following Table 4 shows the components of the elastomeric materials of the comparative Examples 5a and 5b and of Example 5c according to the invention and the respective values of G′, dG′ and tan Delta measured, according to the above methods, on samples vulcanised at 170° C. for 10 minutes:

(94) TABLE-US-00005 TABLE 4 Ex. 5a Ex. 5b Ex. 5c Invention Comparative Comparative SIL + TMMS + SIL + TMMS SIL + MAPOSS MAPOSS Component (amount in phr) SBR 2525 100 100 100 MAPOSS 10 10 Silica 1165 30 30 30 TMMS 2.4 2.4 Stearic acid 2 2 2 6PPD 2 2 2 ZnO 3.5 3.5 3.5 DCP 2 2 2 Properties dG′(0.5-10) 0.59 0.41 2.24 [MPa] dG′(0.5-10)/G′(9) 42% 25% 36% G′ (9%) [MPa] 1.39 1.60 6.24 Tan d (9%) [—] 0.098 0.102 0.149 G′ (3%) [MPa] 1.42 1.85 7.55 Tan d (3%) [—] 0.113 0.074 0.118
Key: MAPOSS Octamethacrylpropyl silsesquioxane (Hybrid Plastic MA0735) formula R═C.sub.7H.sub.11O.sub.2, n=8, 10, 12 (mixture), for other meanings, see the previous key

(95) The comparative example 5b shows that the MAPOSS incorporated alone in the elastomeric composition does not lead to a significant reinforcement, especially as regards the hysteresis at 9% of dynamic deformation, which tends to increase.

(96) Conversely the sample according to the invention of example 5c shows that the elastomeric composition in-situ, that is, prepared by incorporation of silica (C), silanising agent A and silsesquioxane (B) in the elastomeric matrix leads to the maintenance (see Tan d at 3%) or to a limited increase (Tan d at 9%) of the hysteresis, associated with a significant increase in the G′ modulus (431% and 349%, respectively).

(97) The loss of dynamic modulus with increasing deformation or Payne effect d G′ (0.5-10) of the present sample 5b is more significant than it was in the case of the sample of Ex. 4b incorporating the preformed derivatised silica, but it still remains very advantageous (6 times lower) with respect to the loss of module shown by conventional compounds with comparable moduli, such as the bead filler composition, shown in Table 4, comprising much filler, much sulphur and hardening resins.

(98) The comparison of the values of d G′ (0.5-10) [MPa] of the samples of Ex. 5c and of the conventional bead material of Table 4 (2.24 vs. 13.5) highlights the unexpected advantageous effect of the reinforcement materials according to the invention on the Payne effect, even in the case of their preparation in-situ.

(99) The loss of dynamic modulus as a function of the deformation compared to the same dynamic modulus dG′ (0.5-10)/G′(9) (relative Payne effect) also highlights that with respect to the comparative sample of Ex. 4a (comprising silanised silica but not derivatised with MAPOSS), the sample of Ex. 4b according to the invention is less sensitive to the effect of the dynamic deformation: the reinforcement material according to the invention, regardless of its preparation—in-situ or preformed—leads to a decrease of the relative Payne effect (from 42% to 17%) and an exceptional balance between modulus and hysteresis.

(100) The experiment also confirms that without pre-treating the silica with the silanising reagent (A) (TMMS) and the silsesquioxane (B) but derivatising in-situ during mixing, it is possible to obtain that peculiar balance of the material properties—such as a high modulus associated with an acceptable hysteresis—predictive in excellent performance tyre in all those applications where white fillers are conventionally used, such as tread, under-layer, sidewall, sidewall filler, and also in those that require high moduli such as bead filler, rigid under-layers and bead protective layers.

Example 6

(101) In this example, to investigate the correlation between the amount of MAPOSS and the effect on the material properties of interest, elastomeric materials according to the invention (Ex. 6b, 6c and 6d) were prepared, incorporating equal amounts of derivatised silica but at an increasing content of MAPOSS, prepared as described in Example 3c (SIL-TMMS-MAPOSS3), Example 3b (SIL-TMMS-MAPOSS5) and Example 3a (SIL-TMMS-MAPOSS10), respectively.

(102) As a comparison, the comparative material of Example 6a was prepared, in which silica and the silanising agent TMMS were added during the mixing (in-situ), in the absence of MAPOSS.

(103) The following Table 5 shows the components of the elastomeric materials of the comparative Example 6a and of Examples 6b, 6c, 6d of the invention and the respective values of G′, dG′ and tan Delta measured, according to the above methods, on samples vulcanised at 170° C. for 10 minutes:

(104) TABLE-US-00006 TABLE 5 Ex. 6b Ex. 6c Ex. 6d Ex. 6a Invention Invention Invention Conventional Comparative SIL-TMMS- SIL-TMMS- SIL-TMMS- tread SIL + TMMS MAPOSS3 MAPOSS5 MAPOSS10 composition Component (amount in phr) SLR 4630 100 100 100 100 100 SIL-TMMS- 33 MAPOSS3 SIL-TMMS- 33 MAPOSS5 SIL-TMMS- 33 MAPOSS10 Silica 1165 30 65 TESPT 5.2 TMMS 2.4 Stearic acid 2 2 2 2 2 6PPD 2 2 2 2 2 ZnO 3.5 3.5 3.5 3.5 2 DCP 2 2 2 2 Sulphur 1 TBBS 3 Properties dG′(0.5-10) [MPa] 0.071 0.133 0.215 0.311 1.36 dG′(0.5-10)/G′(9) 12% 15% 19% 20% 90% G′ (9%) [MPa] 0.58 0.90 1.15 1.54 1.51 Tan d (9%) [—] 0.070 0.074 0.077 0.077 0.166 G′ (3%) [MPa] 0.61 0.97 1.24 1.67 1.72 Tan d (3%) [—] 0.070 0.074 0.076 0.065 0.194
Key: SLR 4630SBR Styron: containing 47% of vinyl on total monomers

(105) As can be seen in the Table, with the same hysteresis, a significant increase in the modulus values is already observed for a minimum load of MAPOSS. In fact, by comparing the material of Example 6b, comprising 33 phr of SIL-TMMS-MAPOSS3 with the reference material of Example 6a, it is observed that the modulus already increases from 0.578 to 0.903 (G′ at 9%) and from 0.612 to 0.967 (G° at 3%), with a relative percentage increase of about 56% and 58%, respectively.

(106) The increase in the modulus proves even more significant with the increase of the amount of MAPOSS loaded (see Examples 6c and 6d) and the maintaining or reduction of the hysteresis is confirmed at the same time.

(107) As shown in FIG. 2 by the pattern of four curves, there appears to be a direct proportionality between the amount of MAPOSS loaded and the extent of the measured reinforcement.

(108) In conclusion, this experiment showed that even with rather small amounts of MAPOSS it is possible to obtain that peculiar balancing of properties—such as high modulus associated with an acceptable hysteresis—characteristic of the materials according to the invention.

(109) In this case, the Payne effect increases slightly, but remains lower than that of a typical read composition with comparable modulus G′, shown in the last column, and characterized by more than double hysteresis (Tan delta 0.194 vs 0.065 of the sample of Ex. 6d) and a quadrupled Payne effect (dG′ 1.36 vs 0.0.311).

Example 7

(110) This example assessed the effect of the vulcanising system on the effectiveness of the present reinforcement materials, when incorporated into elastomeric materials vulcanised with the vulcanisation system sulphur/CBS most commonly used in elastomeric compounds for tyres rather than with peroxides (DCP) as in the previous examples.

(111) To this end, elastomeric materials according to the invention were prepared, incorporating silica, TMMS and MAPOSS (derivatisation in-situ, Ex. 7b) and comparable amounts of pre-derivatised silica SIL-TMMS-MAPOSS10, prepared as in Example 3d (Ex. 7c), respectively.

(112) As a comparison, the comparative material of Example 7a was prepared, in which silica and the silanising agent TMMS were added during the mixing (in-situ), in the absence of MAPOSS. All samples were vulcanised by the conventional CBS/S system.

(113) The following Table 6 shows the components of the elastomeric materials of the comparative Example 7a and of Examples 7b and 7c of the invention and the respective values of G′, dG′ and tan Delta measured, according to the above methods, on samples vulcanised at 170° C. for 10 minutes:

(114) TABLE-US-00007 TABLE 6 Ex. 7a Ex. 7b Ex. 7c Comparative Invention Invention SIL + SIL + TMMS + SIL-TMMS- TMMS MAPOSS MAPOSS Component (amount in phr) SLR 4630 100 100 100 MAPOSS 10 SIL-TMMS-MAPOSS10 33 Silica 1165 30 30 TMMS 2.4 2.4 Stearic acid 2 2 2 6PPD 2 2 2 ZnO 3.5 3.5 3.5 CBS 3 3 3 Sulphur 1 1 1 Properties dG′(0.5-10) [MPa] 0.101 0.128 0.365 dG′(0.5-10)/G′(9) 17% 14% 28% G′ (9%) [MPa] 0.61 0.94 1.32 Tan d (9%) [—] 0.070 0.073 0.111 G′ (3%) [MPa] 0.65 0.99 1.49 Tan d (3%) [—] 0.069 0.073 0.106
Key: CBS: N-cyclohexyl-2-benzothiazyl sulphenamide (accelerant) Vulkacit® CZ/C—(Lanxess) for other meanings, see previous keys.

(115) As can be seen in Table 6, even changing the vulcanisation system, the trend observed in the previous tests is maintained, that is, for a modest increase in hysteresis, a significant increase in the modulus values is observed. In fact, considering for example the sample of Example 7b with respect to that of Example 7a, it appears that the modulus increases by about 53-54% with virtually constant hysteresis. Wanting to increase in a similar manner the modulus of these materials with conventional fillers of the silica or silanised silica type, one should greatly increase the incorporated amount and a significant simultaneous increase in the hysteresis would be observed at the same time. Even in the case of the material of Example 7c, the modulus increase is much higher than the hysteresis, for example by considering the values at 9%, it is observed that with respect to the reference sample of Example 7a, G′ (at 9%) increases by 116%, while the tan d by only 59%, confirming the unexpected trend imparted by the reinforcement materials according to the invention to the modulus and hysteresis properties.

(116) As is shown in FIG. 3, the modulus of the samples according to the invention (Ex. 7b and 7c) is visibly higher than the standards and in absolute value in the range of values required for the majority of applications in tyres, such as treads, under-layers, sidewalls and sidewall insert. It follows that by reducing the incorporated amount of reinforcement material according to the invention, it is possible to obtain materials with moduli still suitable for use, at the same time characterised by particularly low hysteresis at 70° C.

Example 8

(117) In this example, the reinforcement material according to the invention (Ex. 8b), prepared in-situ by mixing elastomer, silica, TEMS and MAPOSS10, was compared with the comparative reinforcement material (Ex. 8a) prepared under the same conditions but with a different silanising agent, TESPT, which does not include reactive alkenyl functionalities according to the invention. This comparative example follows the teaching of the prior art, in particular of documents U.S. Pat. No. 9,085,676 and J. Nanomaterials vol. 2013, ID 674237.

(118) The following Table 7 shows the components of the elastomeric materials of the comparative Example 8a and of Example 8b of the invention and the respective values of G′, dG′ and tan Delta measured, according to the above methods, measured on samples vulcanised at 170° C. for 10 minutes:

(119) TABLE-US-00008 TABLE 7 Ex. 8a Comparative Ex. 8b SIL + TESPT + Invention MAPOSS10 SIL + TEMS + MAPOSS10 Component (amount in phr) SLR 4630 100 100 Silica 1165 30 30 MAPOSS10 10 10 TEMS 2.4 TESPT 2.4 Stearic ac. 2.0 2.0 ZnO 3.5 3.5 6PPD 2.0 2.0 DCP 2.0 2.0 Properties dG′ (0.5-10) [MPa] 0.928 0.294 G′ (9%) [MPa] 1.530 1.676 Tan d (9%) [—] 0.152 0.084 G′ (3%) [MPa] 1.822 1.874 Tan d (3%) [—] 0.146 0.071
Key: TESPT: bis[3-(triethoxysilyl)propyl]tetrasulphide,
for other meanings, see previous keys.

(120) As can be seen in Table 7, with the same or even greater moduli, the sample according to the invention shows values of hysteresis and dG′ significantly lower than the comparative sample, confirming the importance of the presence of the reactive alkenyl function both on the silanising agent (A) and on the silsesquioxane (B). In fact, the comparative example 8a, in which the silanising agent is devoid of such a reactive function, leads to visibly inferior results.

(121) The diagrams in FIGS. 4a (comparison of moduli) and 4b (comparison of hysteresis) even better highlight the surprising effect of the present reinforcement materials, obtained due to the coupling of a silanising agent (A) and a POSS (B) both substituted with reactive alkenyl functions according to the invention.

Example 9

(122) In this example, the effect of the reinforcement materials according to the invention (Ex. 9c) and comparative (Ex. 9a and 9b) was evaluated in elastomeric compositions comprising polyisoprene and polybutadiene, elastomers commonly used in tyre tread compositions of heavy vehicles, as well as in many other non-tread compositions, such as sidewalls, bead protective layers, sidewall insert, under-layer, bead filler, rubber compounds in all types of tyres. In the polyisoprene and polybutadiene elastomers, vinyl groups are substantially absent.

(123) The following Table 8 shows the components of the elastomeric materials of the comparative Example 9a and 9b and of Example 9c of the invention, the respective rheometric parameters measured on the green samples, the respective filling values at different elongation and break levels, of dynamic modulus E′ and tan delta, and of G′, dG′ and tan delta, measured on samples vulcanised at 170° C. for 15 minutes according to the above methods:

(124) TABLE-US-00009 TABLE 8 Ex. 9c Ex. 9a Ex. 9b Invention Comparative Comparative SIL + TEMS + SIL + TEMS SIL + TEMS MAPOSS Component (amount in phr) Polyisoprene 50 50 50 Poly-butadiene 50 50 50 MAPOSS 4 Silica 1165 40 50 40 TEMS 3.2 4.0 3.2 Stearic acid 2 2 2 6PPD 2 2 2 ZnO 3.5 3.5 3.5 Peroxide 2.3 2.3 2.3 Properties ML 3.96 5.91 2.80 MH 20.6 27.2 27.5 Ts2 1.31 1.13 1.03 T60 6.12 6.06 5.15 T90 13.84 13.65 13.33 CA1 1.57 2.07 2.48 CA3 6.27 8.1 9.67 CR 17.9 18.3 15.9 E′ 23° C. 100 Hz 3.5% 9.23 12.97 15.38 E′ 70° C. 100 Hz 3.5% 7.99 10.96 12.78 Tan d 23° C. 100 Hz 3.5% 0.127 0.139 0.121 Tan d 70° C. 100 Hz 3.5% 0.098 0.105 0.093 MDR 20/170 dG′(0.5-10) [MPa] 0.93 2.13 1.02 dG′(0.5-10)/G′(9) 60% 82% 47% G′ (9%) [MPa] 1.56 2.60 2.16 Tan d (9%) [—] 0.166 0.161 0.150 G′ (3%) [MPa] 2.11 3.84 2.67 Tan d (3%) [—] 0.142 0.126 0.132
Key: Polyisoprene: SKI3 by Nizhnekamskneftekhim; Poly-butadiene: Polybutadiene BR40 by Versalis; Peroxide: 2,5-bis(t-butylperoxy)-2,5-dimethyl hexane at 45% active on silica, Luperox 101KL45 by Arkema, for other meanings see previous keys.

(125) As can be seen from the comparison between the two comparative examples 9a and 9b, by increasing the amount of silica and TEMS associated with it, there is an increase of both static and dynamic moduli, together with a significant increase in the Payne effect, both in absolute terms (0.93 to 2.13) and in relative terms (60% to 82%).

(126) In the material of Example 9b, filler with a larger amount of silica, the hysteresis measured at 100 Hz in compression increases, remains substantially constant at 9% of dynamic shear deformation while it decreases at 3%.

(127) This decrease depends essentially on the greater Payne effect of the latter: with a greater amount of silica, the pattern of the filler itself is stronger and at 3% of dynamic deformation it still brings much elasticity to the material, intended to decrease as the deformation increases. It should also be noted that as the amount of silica increases, the viscosity of the composition strongly increases, which is reflected in the 49% increase of the ML value, from sample 9a to 9b.

(128) The composition of Ex. 9c differs from the reference composition of Ex. 9a only by 4 phr of MAPOSS more, while that of Ex. 9b, in addition to the 4 phr of MAPOSS more, also by 10 phr of silica and 0.8 phr of TEMS less.

(129) The material of the invention of Ex. 9c has a higher static modulus and dynamic modulus not only than those of the most similar reference material 9a but also with respect to the reference material 9b, despite this contains more filler and therefore, predictably, has a higher modulus due to the larger content of the same.

(130) In particular, the filler values at 100% and 300% of elongation (CA1 and CA3) of the material according to the invention 9c are higher than those of the reference 9a by 58% and 54%.

(131) The dynamic compression moduli E′ at 23° C. and 70° C. are higher by 66% and 59% for material 9c, respectively, when compared with those of reference 9a.

(132) The same dynamic compression moduli E′ of the material according to the invention 9c are also higher than those of the material with more filler 9b (18% at 23° C. and 16% at 70° C.).

(133) The most interesting data shown by the elastomeric composition 9c according to the invention is that the increase in the modulus is associated with a decrease in the hysteresis and Payne effect, especially evident in relative terms. In fact, material 9c shows a 47% relative loss of the modulus between 0.5% and 10% deformation, while the reference material 9a shows a 60% loss and the reference material with increased filler 9b shows a 82% loss.

(134) It should also be noted that material 9c according to the invention maintains good load at break values CR, albeit lower than those of the reference compositions 9a and 9b, predictable in much stiffer compositions, but especially shows a low viscosity, which is reflected in a lower ML value not only to the material that is closer in terms of mechanical properties 9b (ML less than half), but also of material 9a (ML lower than 41%).