CN103012882A - Rubber composition with low rolling resistance - Google Patents

Abstract

The invention discloses a rubber composition with a low rolling resistance. The rubber composition is prepared and formed by using modified butylbenzene nanopowder powder and at least one rubber containing unsaturated double bond, a reinforcing agent carbon black and other rubber accessory ingredients. Under the precondition of not reducing the processing property, the vulcanized rubber rolling resistance of the rubber composition is reduced by 15.3% and the wet-skidding resistance property is improved; and the rubber composition is especially used as the tread rubber of the tyre.

Description

A rubber composition with low rolling resistance

technical field

The invention relates to a styrene-butadiene rubber composition, more specifically to a composition composed of modified cross-linked powder rubber, styrene-butadiene rubber and the like and its vulcanized compound.

Background technique

With the increasingly stringent policies and regulations for carbon dioxide emission reduction and the increasing shortage of oil resources, how to reduce vehicle fuel consumption has become the focus of the automotive industry and users. Reducing the rolling resistance of tires is one of the important measures to reduce vehicle fuel consumption.

In the research of reducing the rolling resistance of tire rubber (mainly tread rubber), the so-called "magic triangle" problem of contradictory rolling resistance, wet skid performance and wear resistance has been encountered. Simply increasing the amount of softener can improve the tire's wet skid resistance, but its wear resistance will decrease and rolling resistance will increase. Increasing the amount of reinforcing filler (carbon black or white carbon black) can reduce rolling resistance to a certain extent, but it makes it difficult for the reinforcing filler to disperse evenly in the rubber compound and reduces the wet skid resistance. Increasing the amount of vulcanizing agent, that is, increasing the crosslinking density, has the same effect as increasing the amount of reinforcing filler, reducing rolling resistance and worsening wet skid resistance. In order to achieve the balance of the three aspects of performance, in addition to optimizing the tire structure design, extensive and in-depth research has been carried out on the formulation of rubber materials (mainly tread rubber) at home and abroad. On the one hand, synthesize suitable rubber raw materials (such as solution polystyrene butadiene rubber SSBR, trans polyisoprene TPI, butadiene-isoprene-styrene integrated rubber SIBR, high vinyl butadiene rubber HVBR, etc.), On the other hand, seek modifiers and practical formulations with better comprehensive properties. Some progress has been made in formula research, and the more representative ones are: SSBR, etc. are used in combination with carbon black and white carbon black or reciprocal (reversed) carbon black system. The strong filler is different, and it is easy to realize in industry; its disadvantage is that it needs to use more silane coupling agent and the equipment load is heavy during rubber mixing, and the wear resistance of vulcanized rubber is not ideal.

At the same time, the researchers found that cross-linking powdered rubber, when properly formulated, can reduce the rolling resistance of vulcanizates. The patent US6184296 uses surface-modified cross-linked cis-butadiene and styrene-butadiene powder rubber (swelling index 4-5, particle size 60-450nm), which reduces the rolling resistance of the natural rubber (NR) formula system vulcanizate, and the strength performance is not changed. Affected. In the patent US6133364, chloromethyl styrene is grafted onto the surface of cross-linked styrene-butadiene powder rubber, and then used in the NR formulation system to reduce the rolling resistance of the vulcanized rubber and improve the wet skid resistance. The cross-linked styrene-butadiene powder rubber modified with chloromethylstyrene in the patent US6207757 can reduce the rolling resistance of the vulcanized rubber of the NR formula system, and at the same time improve the traction performance and durability of the tire. The patent US6242534 uses the cross-linked styrene-butadiene powder rubber containing carboxyl and amino groups together in the NR formulation system, which not only reduces the rolling resistance of the vulcanized rubber in the system, improves the wet skid resistance, but also significantly increases the modulus of elongation. Patent EP1431075 uses styrene-butadiene powder rubber and plasticized starch to improve the performance of styrene-butadiene rubber (SBR) and cis-butadiene rubber (BR) and the performance of the silica system. As a result, the wear resistance is improved, the rolling resistance is reduced, and the vulcanized rubber The specific gravity is also smaller. Patent US6699935 uses copolymerized modified cross-linked styrene-butadiene powder rubber to make the modified styrene-butadiene formula system have low rolling resistance and excellent wet skid resistance and wear resistance.

The cross-linked styrene-butadiene powder rubber mentioned in the above-mentioned patent documents is all cross-linked by chemical cross-linking method, which needs to use relatively expensive cross-linking monomers and consumes a lot of energy. The patent documents mainly relate to the natural rubber formulation system or the silica system of styrene-butadiene rubber and the formulation system of modified styrene-butadiene rubber.

the

Contents of the invention

In the present invention, the modified cross-linked styrene-butadiene powder rubber is used in the styrene-butadiene rubber formula system, and as a result, the processing performance of the mixed rubber is basically not affected, and the extrusion expansion is also reduced. The rolling resistance of the vulcanized rubber is significantly reduced, the wet skid resistance is slightly improved, and the wear resistance is basically unchanged. The rubber composition is particularly suitable as a tread compound for passenger tires.

The object of the invention can be realized through the following technical solutions:

The rubber composition of the present invention is mainly composed of styrene-butadiene rubber, modified cross-linked styrene-butadiene powder rubber, isocyanate, silane coupling agent, reinforcing agent, vulcanizing agent, accelerator and other components.

The amount of styrene-butadiene rubber used in the rubber composition is based on 100 parts of pure raw rubber, and the amounts of other components below are all relative to 100 parts of raw rubber. Basic requirements for selection of styrene-butadiene rubber: oil-extended or non-oil-extended emulsion polystyrene-butadiene rubber, preferably oil-extended styrene-butadiene rubber; bound styrene content 15-50%, preferably 20-30%; Mooney viscosity 30-90, preferably 40 ~70.

The modified cross-linked styrene-butadiene powder rubber is used in the rubber composition in an amount of 1-30 parts, preferably 5-15 parts. Preparation of modified cross-linked styrene-butadiene powder rubber: the styrene-butadiene powder rubber prepared by radiation cross-linking method was selected, and the surface of the cross-linked styrene-butadiene powder rubber was modified with hexanedithiol and potassium persulfate in the presence of polyethylene glycol. Basic requirements for selection of cross-linked styrene-butadiene powder rubber: combined styrene content 15-60%, preferably 35-55%; average particle size 50-300nm, preferably 100-200nm; gel content 70-98%, preferably 85-95% %.

The amount of isocyanate in the rubber composition is 1-30 parts, preferably 5-15 parts. The isocyanate is selected from oligomeric isocyanate, which has low volatility and relatively low reactivity and is easy to use.

The reinforcing agent can be carbon black or white carbon black, preferably carbon black. The amount added is 40-120 parts, preferably 70-90 parts. Commonly used carbon black grades are: N110, N115, N120, N125, N135, N220, N231, N234, N242, N293, N299, N326, N330, N335, N339, N343, N351, N356, N375, N539, N550, N660 , N772, N990, etc.

The coupling agent is a sulfur-containing silane coupling agent, commonly used is 3,3'-bis(triethoxymethylsilylpropyl)tetrasulfide (Si69), in addition: 3,3'-bis( Trimethoxymethylsilylpropyl) disulfide, 3,3'-bis(trimethoxymethylsilylpropyl)tetrasulfide, 3,3'-bis(triethoxymethylsilyl) Propyl) disulfide, 3,3'-bis(triethoxymethylsilylpropyl) octasulfide, 3,3'-bis(tributoxymethylsilylpropyl) disulfide , 3,3'-bis(tributoxymethylsilylpropyl)tetrasulfide, etc.

The rubber composition contains processing aids such as vulcanizing agents, accelerators, active agents, anti-aging agents, and extender oils. The vulcanizing agent can be sulfur or a sulfur donor, preferably sulfur, with an amount of 0.5-6 phr, preferably 1.2-3 phr. The commonly used accelerators are N-oxydiethylene-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide and the like. Active agents use traditional zinc oxide and stearic acid. The anti-aging agent is used together with RD and 4020. Aromatic oil is used as the operating oil. The dosages of accelerators, active agents, and anti-aging agents are basically traditional empirical dosages.

the

Detailed ways

Experimental data in the embodiment of this paper is measured with following equipment and measuring method:

(1) Mooney Viscosity: Tested with M200E Mooney Viscometer, the test temperature is 100°C.

(2) Mooney scorch: Tested with M200E Mooney viscometer at a test temperature of 120°C.

(3) Vulcanization characteristics: The vulcanization characteristics of the mixed rubber are tested by a C200E rotorless vulcanizer with a test temperature of 160°C, an oscillation rate of 1.7Hz, and an amplitude of 0.5°.

(4) Main mechanical properties: according to relevant national standards.

(5) Rolling resistance: use a DUNLOP rotating power loss meter to conduct experiments under a constant load of 15Kg and a frequency of 7Hz, preheat to 38°C, and measure the rolling loss. Data were recorded every 10 min and results were expressed as rolling loss (J/r) at 30 min.

(6) Wet skid resistance and abrasion resistance: Use LAT 100 indoor wet skid abrasion machine to measure the abrasion resistance and wet skid resistance of the rubber compound. The abrasion performance test has comprehensive and harsh conditions. The comprehensive conditions are: speed 10km/h, load 75N, inclination 9°. The wet skid resistance test conditions are: speed 6km/h, load 75N, inclination 16°, temperature 20°C.

The purpose of the present invention will be further described below in conjunction with the examples, but the protection scope of the right of the present invention is not limited, and the scope of the present invention is proposed in the claims.

Cross-linked styrene-butadiene powder rubber modification: cross-linked styrene-butadiene rubber powder is selected from VP101 produced by Sinopec Beijing Research Institute of Chemical Industry (combined styrene content 50%, gel content 89%). Weigh 150g of cross-linked powdered rubber and put it into a 1000ml three-neck bottle, add 470ml of water, 4.6g of polyethylene glycol (molecular weight 2000), and 3.4g of 1,6-hexanedithiol into the bottle at the same time to prepare suspension. At 30°C, 2.3% potassium persulfate solution was added dropwise while stirring the suspension, and after 131g of potassium persulfate solution was added dropwise, the temperature was gradually raised to 70°C. Reaction at this temperature for 1h. Thereafter, the temperature of the suspension was lowered to below 40° C., and the modified rubber powder was obtained by filtering, washing and vacuum drying, and the modified rubber powder was used in the following formula.

Comparative example 1-3

The formula composition of rubber composition is shown in Table 1, and the preparation method step of rubber compound is as follows:

A process:

1.57L Farril internal mixer, 80°C/80 rpm.

Add raw rubber, put down the top bolt, and masticate for 0.5min.

Raise the top bolt, load carbon black and other small materials (except sulfur, accelerator, oil), lower the top bolt, and knead for 3 minutes.

Raise the top bolt, load aromatic oil, lower the top bolt, and knead for 2.5 minutes.

Degumming (temperature at 150-160°C).

Two-stage process:

6 inch open mixer.

A piece of masterbatch → → sulfur, accelerator → → thin pass six times → → next film.

(Note: In the formula, the modified rubber powder and raw rubber are added together, and N3200 and oil are added together)

Table 1 Comparative example and embodiment formula

material name Comparative example 1 Comparative example 2 Comparative example 3 Example SBR1712* 137.5 137.5 137.5 137.5 Modified VP101 the 10 10 10 N3200** the the 10 10 Si69 the the the 2 N234 75 75 75 75

illustrate

Other additives: aromatic oil 5; zinc oxide 3; stearic acid 2; protective wax 1.5; anti-RD 1; anti-4020 1; sulfur 1.5; promoting NS 1.4; promoting DPG 0.3.

*Oil-extended Emulsion Styrene Butadiene Rubber, with a combined styrene content of 23% and a Mooney viscosity of 50.

**Isocyanate oligomers, produced by Bayer AG.

Example

The formula composition of the rubber composition is listed in Table 1, and the preparation of the rubber compound is the same as that of the comparative example.

The main properties of the rubber compositions of Comparative Examples and Examples are listed in Tables 2-4.

As can be seen from the results of Table 3 and Table 4, the embodiment has reached a good balance in terms of rolling resistance, wet skid resistance and wear resistance. Compared with Comparative Example 1, the rolling resistance has reduced by 15.3%, and the wet skid resistance Slightly improved, wear resistance is largely unaffected. At the same time, the compression fatigue temperature rise of the rubber composition of the example is also small. The rolling resistance of Comparative Example 2 was only reduced by 5%, and the rolling resistance of Comparative Example 3 was greatly reduced, but the wear resistance was seriously affected.

The rubber composition of the invention has obvious performance advantages, and is especially suitable for use as a tire tread compound.

Table 2 Vulcanization characteristics and Mooney scorch of rubber composition compounds

Table 3 The physical and mechanical properties of the rubber composition after vulcanization

project Comparative example 1 Comparative example 2 Comparative example 3 Example Hardness (Shore A) 63 66 64 68 100% modulus stress/MPa 1.49 1.78 1.96 2.38 300% modulus stress/MPa 7.66 8.80 7.11 10.6 Tensile strength/MPa 22.7 21.4 12.7 17.1 Elongation at break/% 674 605 544 485 Permanent deformation/% 30 20 twenty two 26 Tear strength/kN·m ^-1 49 44 45 47 Effective Elasticity% 29 twenty one 32 28 Compression fatigue temperature rise ℃ 46.0 43.4 47.8 42.8

Table 4 Wear resistance, wet skid resistance and rolling resistance of the rubber composition after vulcanization

project Comparative example 1 Comparative example 2 Comparative example 3 Example wear index 100.0 96.7 58.8 98.8 wet skid resistance 100.0 103.0 98.3 102.0 rolling resistance 100.0 95.0 82.5 84.7

Claims (6)

1. A rubber composition with low rolling resistance , comprising blended 100 parts by weight of styrene-butadiene rubber and 1-30 parts by weight of modified styrene-butadiene powder rubber. 2. A rubber composition with low rolling resistance as claimed in claim 1, characterized in that the bound styrene content in the blended styrene-butadiene rubber is 20-30%, and the Mooney viscosity is 40-70. 3. A kind of rubber composition with low rolling resistance as claimed in claim 1, it is characterized in that, the bound styrene content in the blended modified styrene-butadiene powder rubber is 35～55%, average particle diameter 100～200nm, The gel content is 85-95%. 4. A rubber composition with low rolling resistance as claimed in claim 1, characterized in that the amount of oligomeric isocyanate is 1-30 parts by weight. 5. A rubber composition with low rolling resistance as claimed in claim 1, characterized in that the amount of the silane coupling agent is 0.1-5 parts by weight. 6. A kind of rubber composition with low rolling resistance as claimed in claim 1, is characterized in that, the styrene-butadiene rubber of blending is oil-extended styrene-butadiene rubber.