Method for preparing high performance tread rubbers through filler silylation reaction catalyzed in situ by ionic liquids

Abstract

The present invention discloses a method for preparing high-performance tread rubber through a filler silylation reaction catalyzed in situ by an ionic liquid. The method is as follow: adding a gum rubber, a filler, a silane and an ionic liquid successively into an open mill or an internal mixer for mixing to obtain a rubber compound; high-temperature remilling the rubber compound; adding a vulcanizing package and an anti-aging agent into the remilled rubber compound at room temperature; and vulcanizing the rubber compound to obtain a vulcanized rubber.

Claims

1. A method for preparing a tread rubber through a filler silylation reaction catalyzed in situ by an ionic liquid, wherein the method comprises following steps: (1) adding a gum rubber, a filler, a silane and the ionic liquid successively into an open mill or an internal mixer for compounding to obtain a rubber compound, wherein the filler comprises a carbon black and a light-colored filler, wherein the light-colored filler is a silica, a clay a metallic oxide, or any combinations there of, and the silane is a sulfur-containing trialkoxysilane, the light-colored filler accounts for at least 10 wt % of all the filler, an amount of the silane is 2 wt % to 10 wt %, relative to the light-colored filler, and an amount of the ionic liquid is 1 wt % to 8 wt %, relative to the light-colored filler; (2) remilling the rubber compound at a temperature of 125 C. to 155 C. for 5 to 15 minutes; (3) adding a vulcanizing package and an anti-aging agent into the remilled rubber compound at room temperature; and (4) vulcanizing the rubber compound to obtain a vulcanized rubber.

2. The method according to claim 1, wherein in step (1), the rubber compound has a rubber content of 32 wt % to 42 wt %.

3. The method according to claim 1, wherein the gum rubber is a basic rubber for a tread rubber, the basic rubber consists of a natural rubber, a solution-polymerized styrene-butadiene rubber, and a high cis-polybutadiene rubber, and an amount of the high cis-polybutadiene accounts for 25 wt % to 35 wt % of the gum rubber.

4. The method according to claim 1, wherein the gum rubber is a basic rubber of a tread rubber, the basic rubber consists of a natural rubber and a cis-polybutadiene rubber, or a solution polymerized styrene-butadiene rubber and a cis-polybutadiene rubber, and an amount of the cis-polybutadiene accounts for 25 wt % to 35 wt % of the gum rubber.

5. The method according to claim 1, wherein the ionic liquid is an ionic molten salt with a melting point below 100 C., including dialkyl imidazoles, alkyl pyridines or organophosphorus salts.

6. The method according to claim 1, wherein in step (1), a time for the mixing is 5 to 10 minutes.

7. The method according to claim 1, wherein the vulcanizing package is a system of sulfur cooperating with a vulcanizing activator and an accelerator, or a system of peroxide cooperating with an activator, or a system of sulfur being combined with peroxide.

8. The method according to claim 1, wherein the anti-aging agent comprises one or more than one of p-phenylenediamines and quinolines.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) The present invention will be further described in detail below in combination with specific embodiments, but the implementations of the present invention are not limited to these. As for technological parameters which are not particularly specified, they can be implemented in accordance with conventional technology.

(2) (1) Adding a gum rubber, a filler, a silane and an ionic liquid successively into an open mill for compounding for 10 minutes to obtain a rubber compound;

(3) (2) high-temperature remilling the rubber compound;

(4) (3) adding a necessary vulcanization system and an anti-aging system into the remilled rubber compound at room temperature; and

(5) (4) vulcanizing the rubber compound to obtain a vulcanized rubber.

(6) In step (2), the high-temperature remilling was conducted in the open mill at a temperature of 145 C. for 8 minutes.

(7) In step (4), the vulcanizing refers to vulcanization at 150 C. according to an optimum cure time in Table 2.

(8) In order to verify advantages of the method according to the present invention, a formula for tire tread rubber using solution-polymerized styrene-butadiene rubber and cis-polybutadiene rubber as basic rubbers was chosen, and types and contents of different silanes and ionic liquids were chosen. A control sample and four embodiments were prepared according to the above-said method in the present invention. Specific formulas are shown as Table 1, wherein units in the table are all gram.

(9) TABLE-US-00001 TABLE 1 Formulas for the comparative sample and the embodiments Control Formula sample Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 SSBR (VSL4526-2HM), 55 55 55 55 55 containing 30% of oil SSBR (Sinopec Shanghai 30 30 30 30 30 Gaoqiao Petrochemical Co., Ltd 2003) Rare earth cis-polybutadiene 30 30 30 30 30 (CB24) Highly-dispersible silica (Utrasil 50 50 50 50 50 7000GR) Carbon black (N375) 20 20 20 20 20 Silane (Si69) 5 1 0 1 1 Silane (Si75) 0 0 1 0 0 Zinc oxide 3 3 3 3 3 Stearic acid 2 2 2 2 2 Anti-aging agent 4010 2 2 2 2 2 Paraffin 1.5 1.5 1.5 1.5 1.5 Accelerator NS 1.8 1.8 1.8 1.8 1.8 Accelerator TMTD 0.3 0.3 0.3 0.3 0.3 Sulfur 2.3 2.3 2.3 2.3 2.3 Hexadecyl triphenyl 0 1 1.5 0 0 phosphonium chloride N-butylpyridinium 0 0 0 1.5 0 bis((trifluoromethyl)sulfonyl)imide 1-methyl-3-nonylimidazolium 0 0 0 0 0.8 tetrafluoroborate

(10) According to the corresponding China National Standards, properties of all formulas were tested, and typical performance thereof is listed in Table 2. As shown in Table 2, the method according to the present invention can significantly reduce rolling resistance (shown as tan delta at 60 C.) and heat build-up of the tread rubber, and significantly improve modulus of the vulcanized rubber. In the meantime, amounts of the silane in the formulas have been greatly reduced.

(11) TABLE-US-00002 TABLE 2 Typical properties of the control sample and embodiments Control Test item sample Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Optimum cure time (min) 17.5 14.3 10.5 11.4 13.5 Tensile strength (MPa) 20.2 21.7 21.5 22.0 20.6 M300 (MPa) 13.1 17.5 18.1 16.9 17.7 Elongation at break (%) 410 330 340 350 320 Tan delta (60 C., strain 0.135 0.105 0.107 0.11 0.106 7%, 10 Hz) Heat build-up ( C.) 33 26 25 23 24 Akron abrasion 1.61 1.53 1.47 1.62 1.45 (cm.sup.3/1.61 km)

(12) Above-mentioned embodiments of the present invention are examples only for clearly illustrating the present invention, but not for limiting the implementations of the present invention. For those ordinarily skilled in the art, other different forms of variation or alteration can also be made based on the above description. There's no need or no way for all the implementations to be exhaustive. Any modification, equivalent replacement and improvement made within the spirit and the principle of the present invention shall be comprised within the scope of protection of the claims of the present invention.