阅读说明：本技术 一种全钢载重子午线轮胎配方胶料及其制备方法 (Formula rubber material for all-steel load radial tire and preparation method thereof ) 是由 姚琼 张建国 蒋文英 付为金 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种全钢载重子午线轮胎配方胶料及其制备方法,在全钢载重子午线轮胎配方胶料的胎面胶料、胎侧胶料和胎基部胶料均使用了具有宽分布、高熔体弹性、高支化、高反式1,4-加成单元含量和含有梯度分布的多嵌段单元的丁二烯-异戊二烯共聚橡胶(BIR)与天然橡胶或/和丁苯橡胶等。该配合复合料具有优良的加工性能,复合硫化胶料体现出好的相容性、高强度、低生热、耐屈挠、抗龟裂、耐老化和抗湿滑、低滚动阻力的特点。(The invention discloses a formula rubber material of an all-steel truck radial tire and a preparation method thereof, wherein butadiene-isoprene copolymer rubber (BIR) and natural rubber or/and styrene-butadiene rubber and the like which have wide distribution, high melt elasticity, high branching, high trans-1, 4-addition unit content and multi-block units containing gradient distribution are used for a tread rubber material, a side wall rubber material and a tire base rubber material of the formula rubber material of the all-steel truck radial tire. The compound material has excellent processing performance, and the compound vulcanized rubber has the characteristics of good compatibility, high strength, low heat generation, flex resistance, cracking resistance, aging resistance, wet skid resistance and low rolling resistance.)

1. The all-steel load radial tire formula rubber material comprises a tread rubber material, a sidewall rubber material and a tire base rubber material, and is characterized in that:

the tread rubber material, the sidewall rubber material and the tire base rubber material all comprise butadiene-isoprene rubber containing gradient multiblock;

the gradient multi-block butadiene-isoprene rubber has the following expression;

R—B₁I_mB₂I_m-1……B_m-1I₂B_mI₁D—F

wherein the content of the first and second substances,

r is an initiator residue;

m is the number of micro blocks;

B₁……B_mis m butadiene homopolyblocks and is derived from B₁To B_mThe chain length of the butadiene homopolymerization block is gradually reduced;

I₁……I_mis m isoprene homo-blocks and is prepared from₁To I_mThe chain length of the isoprene homopolymerization block is gradually decreased;

d is a divinylbenzene branching unit, and the average branching degree is 1-2.5;

f is a polar end capping group;

the number average molecular weight Mn of the butadiene-isoprene rubber containing the gradient multi-block is 15-25 multiplied by 10⁴The molecular mass distribution index is 2.5-3.5.

2. The all-steel truck radial tire formula rubber compound as claimed in claim 1, wherein the formula rubber compound is characterized in that: the number proportion of 1, 2-addition units of butadiene and 3, 4-addition units of isoprene in the butadiene rubber containing gradient multi-block is less than 10%, and the number proportion of trans-1, 4 addition units of polyisoprene and polybutadiene units is higher than 75%.

3. The all-steel truck radial tire formula rubber compound as claimed in claim 1, wherein the formula rubber compound is characterized in that: the Mooney viscosity ML of the raw rubber containing the gradient multi-block butadiene-isoprene rubber is 50-70.

4. The all-steel truck radial tire formula rubber compound as claimed in claim 1, wherein the formula rubber compound is characterized in that: the polar end capping group of the butadiene-isoprene rubber containing the gradient multi-block is a polar group containing at least one element of tin, nitrogen, oxygen and silicon.

5. The all-steel truck radial tire formula rubber compound according to any one of claims 1 to 4, characterized in that: the tread rubber material, the sidewall rubber material and the tire base rubber material all contain butadiene-isoprene rubber containing gradient multi-block, NR and/or styrene-butadiene rubber and auxiliary materials.

6. The all-steel truck radial tire formula rubber compound as claimed in claim 5, wherein the formula rubber compound is characterized in that: the base rubber material comprises the following components in parts by mass: 15-25 parts of NR; 40-50 parts of butadiene-isoprene rubber containing gradient multiblock; 150030-40 parts of ESBR; 55-65 parts of carbon black; 8-15 parts of operating oil; 4-6 parts of zinc oxide; 1-3 parts of stearic acid; 2-4 parts of an anti-aging agent; 2-4 parts of an accelerator; 1.2-1.8 parts of sulfur.

7. The all-steel truck radial tire formula compound according to claim 6, characterized in that:

the accelerators include accelerator NS and accelerator CZ;

the carbon black is nano furnace carbon black.

8. The all-steel truck radial tire formula rubber compound as claimed in claim 5, wherein the formula rubber compound is characterized in that: the tire side rubber material comprises the following components in parts by mass: 25-35 parts of butadiene-isoprene rubber containing gradient multiblock; ESBR 150065-75 parts; 60-70 parts of carbon black; 8-15 parts of rubber oil; 1-3 parts of protective wax; 6-8 parts of zinc oxide; 1-3 parts of stearic acid; 2-4 parts of an anti-aging agent; 2-4 parts of an accelerator; 1.5-2.0 parts of sulfur.

9. The all-steel truck radial tire formula compound according to claim 8, characterized in that:

the accelerator comprises accelerator NS and accelerator D;

the carbon black is nano furnace carbon black.

10. The all-steel truck radial tire formula rubber compound as claimed in claim 5, wherein the formula rubber compound is characterized in that: the tread rubber material comprises the following components in parts by mass: 25-35 parts of SSBR; 25-35 parts of butadiene-isoprene rubber containing gradient multiblock; 35-45 parts of NR; 25-35 parts of white carbon black; 20-30 parts of carbon black; 4-6 parts of zinc oxide; 1-3 parts of stearic acid; 7-9 parts of a silane coupling agent; 1-3 parts of an anti-aging agent; 0.5-1.5 parts of an anti-aging agent; 0.5-1.5 parts of protective wax; 6.5-7.5 parts of TDAE; 1.5-2.5 parts of sulfur; 2-4 parts of an accelerator.

11. The all-steel truck radial tire formula compound according to claim 10, characterized in that: the promoter comprises promoter CZ and promoter D;

the specific surface area of the white carbon black is more than 200m²/g；

The SSBR includes at least one of VSL-5025H, SSBR 63 and SSBR 2560.

12. The preparation method of the all-steel truck radial tire formula rubber compound of any one of claims 1 to 10, characterized by comprising the following steps: mixing raw materials including the gradient multi-block butadiene-isoprene rubber I to form master batch; mixing the master batch with sulfur II to obtain mixed rubber; and vulcanizing the rubber compound to obtain the rubber composition.

13. The preparation method of the all-steel truck radial tire formula compound according to claim 12, characterized by comprising the following steps: the mixing I is carried out in an internal mixer, and the mixing is carried out for 90-120 s at the temperature of 120-140 ℃.

14. The preparation method of the all-steel truck radial tire formula compound according to claim 12, characterized by comprising the following steps: and the mixing II is carried out on an open mill at the temperature of 50-60 ℃.

15. The preparation method of the all-steel truck radial tire formula compound according to claim 11, characterized by comprising the following steps: the vulcanization is carried out at the temperature of 160-170 ℃ for 10-20 min.

Technical Field

The invention relates to a formula sizing material for an all-steel truck radial tire, in particular to a formula sizing material for an all-steel truck radial tire taking polybutadiene-isoprene rubber and natural rubber which have the characteristics of a plurality of polyisoprene blocks with orderly and gradient distribution of chain lengths, a trans-1, 4 structure, wide distribution and the like as main components and a preparation method thereof, belonging to the field of tire rubber.

Background

The tire is an important safety part of an automobile, the tire industry is one of important fields of national economic development, when a heavy-duty or passenger car tire runs on a high-speed road for a long time, the tire is subjected to periodic compression deformation and high-frequency bending and straightening motions, and the tire and the ground are severely rubbed, the generated resistance is increased to generate a large amount of heat, and the temperature of the tire is quickly increased due to the heat accumulation to a certain degree, so that the tire generates high temperature. The adverse effect of high temperature on the tire can increase the air pressure, deform the tire, reduce the elasticity of a tire body, increase the dynamic load of the automobile, reduce the strength of the tire side, tire crown and tire tread base rubber under the high temperature, and cause internal cracking or tire burst if the tire side, tire crown and tire tread base rubber are impacted, which is also the reason for concentrated burst of the automobile in a long-time running state. In addition, if the synthetic rubbers in the composite material of the tire are mutually matched or have poor compatibility, the crack generation has a greater influence on the tire burst.

The bursting of the tire mainly occurs to the tread and the side wall part, and the amount of the rubber used for the tread and the side wall part accounts for more than 2/3 of the whole tire. The traditional truck tire tread rubber is generally composed of 20-70 parts of SBR, 30 parts of BR, 0-50 parts of NR, 11 parts of operating oil, 55-60 parts of hard carbon black and the like; the base of the tire tread comprises 35-55 parts of SBR, 45 parts of BR, 0-20 parts of NR, 11 parts of operating oil, 60-65 parts of hard carbon black and the like; the sidewall portion is composed of SBR 70, BR 30, process oil 11, hard carbon black 65, and the like. However, the compatibility of BR and NR in the tread or base rubber of the tire is poor, and cracks are generated after a long time, so that the service life of the tire and the run-flat safety of the tire are influenced.

The catalysts made from polybutadiene-isoprene (BIR) rubber include transition metals, lithium series and rare earth. The T-BIR prepared by the Ti-Mg coordination catalytic system has low compression heat generation, fatigue resistance, tear resistance, wear resistance and low noise, has outstanding crude rubber strength, is an ideal rubber material for high-performance tires, and has the defects that the monomer conversion rate is less than 70 percent, the self-adhesiveness of the crude rubber is low, and the processability is poor when the viscosity is high; in the synthesis of the BIR synthesized by the existing lithium-based catalysis, the 1, 4-addition content of butadiene and isoprene is increased along with the increase of the polymerization temperature, and the 1.2-and 3, 4-addition content is reduced, but the molecular mass distribution of the polymer is too narrow, the green strength is low, the cold flow is large, the processability is poor, and the like.

Patent GB2029426.1980 and US4413089.1983 Isoprene-butadiene Copolymer rubber with improved processing properties "describes random or block copolymers obtained by copolymerization of butadiene and isoprene using barium salt-lithium tributyl magnesium/trialkylaluminum catalysis, which have a Mooney viscosity of 59 and a molecular weight distribution D of 1.46, and which are excellent in processability and gum-forming tack and can be used in combination with natural rubber NR. CN103387641A introduces a trans-1, 4-structured butadiene-isoprene copolymer rubber and a preparation method thereof. Using MgCl₂The butadiene-isoprene copolymer rubber with a trans-1, 4-structure of more than 90% is synthesized by catalyzing butadiene and isoprene to copolymerize by a Ziegler-Natta catalytic system consisting of supported titanium and an organic aluminum compound, and the copolymer rubber consists of 20-99.5% of isoprene units and 0.5-80% of butadiene units in molar fraction. The trans-copolymer rubber has the characteristics of low heat generation, good wear resistance and excellent flex fatigue resistance, and is suitable for dynamically used rubber products.

TBIR is applied to tire bead protection rubber in the text of structural characterization of high trans-1, 4-butadiene-isoprene copolymer rubber and application research thereof in the bead protection rubber of car tires, 2015.12, 12, so that the crystallinity, the green strength and the hardness of rubber compound can be increased, and the vulcanization speed is accelerated; other properties of the TBIR-containing blended vulcanized rubber are kept unchanged, compression temperature rise is obviously reduced, and abrasion resistance and aging resistance are obviously improved; the compatibility of TBIR with NR is superior to BR. The result shows that after NR is used together with TBIR, the carbon black in vulcanized rubber has better dispersibility, about 20 parts of TBIR is applied to the bead protector of the radial tire of a passenger car, other mechanical properties are kept at a higher level, meanwhile, the wear resistance, the flex resistance and the aging resistance are obviously improved, and the compression temperature rise is obviously reduced. The application of a new generation of synthetic rubber-trans-1, 4-butadiene-isoprene copolymer rubber (TBIR) in high-performance passenger car tire tread rubber [ solution polymerized styrene-butadiene rubber/butadiene rubber (SSBR/BR) ] and the structure and performance of an SSBR/BR/TBIR blended rubber are described in the structural and performance of the high-performance passenger car tire tread rubber modified by the trans-1, 4-butadiene-isoprene copolymer rubber (high molecular report, 03 of 2018). 10-20 parts of TBIR and SSBR/BR are modified simultaneously, 30 parts of carbon black and 45 parts of white carbon black are added simultaneously, the Green strength and the stress at definite elongation of the SSBR/BR/TBIR rubber compound are improved, the scorching time (tc10) and the normal vulcanization time (tc90) are basically kept unchanged, the vulcanized rubber of the SSBR/BR/TBIR rubber compound has excellent physical and mechanical properties, the tensile fatigue resistance is improved by 4.6-6.3 times, the compression strength is improved by 21.4-23.1%, the wear resistance is improved by 10.8-15.1%, the wet-slip resistance is improved by 13.6-40.4%, and the rolling resistance is kept unchanged. Compared with SSBR/BR vulcanized rubber, the dispersion degree of the SSBR/BR/TBIR vulcanized rubber filler is improved by 7.3-14.9%, and the average size of the filler aggregate is reduced by 1.4-2.7 μm. The high green rubber strength and modulus of the crystallizable TBIR can obviously inhibit the aggregation of the filler in the rubber compound, improve the dispersibility of the filler in the vulcanized rubber, and finally contribute to the excellent tensile fatigue resistance, high wear resistance, wet skid resistance, compressive strength, constant tensile modulus and other properties of the SSBR/BR/TBIR vulcanized rubber, wherein the TBIR is an ideal novel synthetic rubber applied to the high-performance car tire tread rubber.

In patent JP 2009287020A, "a formulation of a compound having low heat build-up and high abrasion resistance and a tire made therefrom" is reported. In the formula, 80 parts of solution polymerized styrene-butadiene rubber consisting of half-functionalized modified high-polybutadiene content, 20 parts of NR, 70 parts of carbon black, 30 parts of unmodified styrene-butadiene rubber, 2 parts of stearic acid, 2.5 parts of zinc oxide, 1 part of antioxidant, 1.3 parts of accelerator and 1.5 parts of sulfur are adopted, and the vulcanized rubber has the characteristics of good wear resistance and low heat generation and can be used as rubber for treads, tread bases, sidewalls or inner liners. The technical disadvantage is that NR still has poor compatibility with polybutadiene in styrene butadiene rubber.

China CN105670065A introduces an ultra-low rolling resistance tire tread rubber material, a preparation method thereof and a tire, and particularly relates to an ultra-low rolling resistance tire tread formula, a preparation method thereof and a tire. The tread rubber material is prepared by mixing the following raw materials: 50.0-110.0 parts of solution polymerized styrene-butadiene rubber; 10.0-30.0 parts of butadiene rubber; 50.0-110.0 parts of high-dispersion white carbon black; aromatic oil 5.0-40.0 weight portions; 8.0-17.6 parts of a silane coupling agent; accelerator DPG: 1.0-4.0 parts; the tire rolling resistance of the tread rubber material reaches below 6.0.

At present, the conventional belt layer and sidewall usually adopt NR and BR as substrates, the tread rubber adopts styrene butadiene rubber and BR as substrates, and the steel wire or cord layer adopts NR as a substrate, namely, the total mass fraction of NR raw rubber in the tire is not less than 27%, and BR is required to be used in each part of the tire. The total crude rubber consumption in the tire is not less than 45%. The adhesion and vulcanization crosslinking of the composite rubber material of the matrix of each part of the tire belong to micro-crosslinking, and the rubber used for each part of the tire is homogeneous in macroscopic view due to poor compatibility of NR and BR; however, microscopic analysis shows that BR and NR are separated after vulcanization, and the defects of tire layer tearing, tire layer falling, tire tread cracking, aging and the like are easy to occur. This is not in line with the requirement of green development of the current high-performance all-steel truck radial tire.

The application of lithium system with suitable side chain content and higher trans-polybutadiene-isoprene rubber in all-steel heavy duty radial tires is not reported frequently.

Disclosure of Invention

The rubber tire aims at the technical problems that compatibility of Natural Rubber (NR) and styrene butadiene rubber matched with BR in the existing tire is poor, NR and BR in vulcanized rubber are separated, so that the rubber material is easy to tear and fall off, a tire body is easy to crack and age, and compatibility of a tire tread, a tire belt layer and a tire side of the tire is poor.

The first purpose of the invention is to obtain a multi-block polybutadiene-isoprene rubber with higher side branch chain and trans-1, 4 addition unit in molecular structure, wide molecular mass distribution, long chain branching and ordered gradient distribution by using the existing anionic polymerization method, wherein the multi-block polybutadiene-isoprene rubber is respectively matched with solution polymerized styrene butadiene rubber (SSBR) to be used as tread rubber of a tire, and is matched with NR to be used as belt layer of the tire and rubber for side wall of the tire, the rubber for each part of the manufactured tire uses micro-block and multi-block polybutadiene-isoprene rubber and NR and other compound rubbers, the connection and bonding surfaces among a tire base, the side wall and the tread rubber are ensured to have the same collagen, a complete compatibility whole is formed after vulcanization, and finally the tire has low rolling resistance, high wet skid resistance, low heat generation, high wear resistance, flex fatigue resistance and the like, Aging resistance, crack resistance and tearing resistance. The invention can be used for manufacturing radial high-performance semi-steel tires and is also suitable for all-steel truck radial tires.

Another object of the present invention is to provide a process for manufacturing said high-performance tyre, which is simple to operate and at low cost.

In order to achieve the technical purpose, the invention provides a formula rubber compound of an all-steel truck radial tire, which comprises a tread rubber compound, a sidewall rubber compound and a tire base rubber compound, wherein the tread rubber compound, the sidewall rubber compound and the tire base rubber compound all comprise a multi-block butadiene-isoprene rubber containing gradient;

the gradient multi-block butadiene-isoprene rubber has the following expression;

R—B₁I_mB₂I_m-1……B_m-1I₂B_mI₁D—F

wherein the content of the first and second substances,

r is an initiator residue;

m is the number of micro blocks;

B₁……B_mis m butadiene homopolyblocks and is derived from B₁To B_mThe chain length of the butadiene homopolymerization block is gradually reduced;

I₁……I_mis m isoprene homo-blocks and is prepared from₁To I_mThe chain length of the isoprene homopolymerization block is gradually decreased;

d is a divinylbenzene branching unit, and the average branching degree is 1-2.5;

f is a polar end capping group;

the number average molecular weight Mn of the butadiene-isoprene rubber containing the gradient multi-block is 15-25 multiplied by 10⁴The molecular mass distribution index is 2.5-3.5.

The butadiene-isoprene rubber containing the multi-block gradient contains a plurality of polyisoprene blocks, and the chain lengths of the blocks are distributed in a regular gradient, so that BIR with molecular configuration is beneficial to being compatible with natural rubber, and the BIR and NR are not separated in vulcanized rubber.

As a preferred scheme, the number proportion of 1, 2-addition units of butadiene and 3, 4-addition units of isoprene in the butadiene rubber containing gradient multi-block is less than 10%, and the number proportion of trans-1, 4-addition units of polyisoprene and polybutadiene units is higher than 75%.

In a preferred embodiment, the raw rubber containing the gradient multi-block butadiene-isoprene rubber has a Mooney viscosity ML of 50 to 70.

As a preferable scheme, the molecular chain terminal of the butadiene rubber containing the gradient block contains a polar end-capping group. The polar group is a polar group containing at least one element of tin, nitrogen, oxygen and silicon. The polar end capping group enables a composite material consisting of raw rubber and other rubber seeds and carbon black to be mixed and dispersed easily, reduces the Payne effect of vulcanized tread rubber of the composite material, shortens the length and concentration of an inert unit from a final crosslinking point of vulcanized network macromolecules to a chain end, and increases effective elastic recovery of the macromolecules, so that energy generated in periodic deformation is converted into stored energy easily, and the heat generation and hysteresis loss of tires are reduced. These polar end capping groups are well known in the art.

As a preferable scheme, the tread rubber material, the sidewall rubber material and the tire base rubber material all contain the multi-block butadiene-isoprene rubber with gradient, NR and/or styrene-butadiene rubber and auxiliary materials. The auxiliary materials are mainly the auxiliary materials used in the tread rubber material, the sidewall rubber material and the tire base rubber material which are common in the field, such as carbon black, rubber softening oil or operating oil, carbon black, zinc oxide, stearic acid, an anti-aging agent, an accelerator, sulfur and the like.

As a more preferable scheme, the base rubber material comprises the following components in parts by mass: NR 15-25; 40-50 parts of butadiene-isoprene rubber containing gradient multiblock; 150030-40 parts of ESBR; 55-65 parts of carbon black; 8-15 parts of operating oil; 4-6 parts of zinc oxide; 1-3 parts of stearic acid; 2-4 parts of an anti-aging agent; 2-4 parts of an accelerator; 1.2-1.8 parts of sulfur.

As a more preferred option, the accelerators in the subtread stock include accelerator NS and accelerator CZ.

Preferably, the carbon black in the base rubber is an industrial furnace carbon black, such as N234.

The most preferred base rubber material comprises the following components in parts by mass: NR 20 parts; 45 parts of butadiene-isoprene rubber containing gradient multiblock; ESBR 150035 parts; 60 parts of N234 carbon black; 11 parts of operating oil TDAE; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; 3.0 parts of an anti-aging agent RD; 1.3 parts of accelerator CZ; 1.8 parts of an accelerator D; 1.6 parts of sulfur.

As a more preferable scheme, the sidewall rubber compound comprises the following components in parts by mass: 25-35 parts of butadiene-isoprene rubber containing gradient multiblock; ESBR 150065-75 parts; 60-70 parts of carbon black; 8-15 parts of rubber oil; 1-3 parts of protective wax; 6-8 parts of zinc oxide; 1-3 parts of stearic acid; 2-4 parts of an anti-aging agent; 2-4 parts of an accelerator; 1.5-2.0 parts of sulfur.

As a more preferred approach, the accelerators in the sidewall compound include accelerator NS and accelerator D.

The most preferable rubber for the tire side part comprises the following raw materials in parts by mass: 30 parts of gradient multiblock butadiene-isoprene rubber (BIR); ESBR 150070 parts; 65 parts of N234 carbon black; 12 parts of NAP-10 rubber oil; 2.0 parts of protective wax; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; 3.0 parts of an anti-aging agent RD; 1.5 parts of accelerator NS; 1.3 parts of an accelerant D; 1.8 parts of sulfur.

As a more preferable scheme, the tread compound comprises the following components in parts by mass: 25-35 parts of SSBR; 25-35 parts of butadiene-isoprene rubber containing gradient multiblock; 35-45 parts of NR; 25-35 parts of white carbon black; 20-30 parts of N234 carbon black; 4-6 parts of zinc oxide; 1-3 parts of stearic acid; 7-9 parts of a silane coupling agent; 1-3 parts of an anti-aging agent; 0.5-1.5 parts of an anti-aging agent; 0.5-1.5 parts of protective wax; 6.5-7.5 parts of TDAE; 1.5-2.5 parts of sulfur; 2-4 parts of an accelerator.

As a more preferred option, the accelerators in the tread compound include accelerator CZ and accelerator D.

As a more preferred option, the white carbon black in the tread compound has a specific surface area of more than 200m²/g。

As a more preferred aspect, the SSBR in the tread compound comprises at least one of VSL-5025H, SSBR2563 and SSBR 2560.

The most preferable tread rubber comprises the following raw materials in parts by mass: an oil-extended SSBR 30; 30.0 parts of gradient block butadiene-isoprene rubber (BIR); NR 40 parts; 30 parts of white carbon black; 25 parts of N234 carbon black; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; si-698.0 parts; 40102.0 parts of anti-aging agent; 1.0 part of an anti-aging agent RD; 1.0 part of protective wax; 7.0 parts of TDAE; 1.8 parts of sulfur; 1.7 parts of accelerator CZ; and 1.3 parts of an accelerator D.

The specific surface area of the white carbon black of the invention is more than 200m²(ii) in terms of/g. White carbon black is suitably added to reduce rolling heat generation of the tire, and it is preferably highly dispersed white carbon black for green tire, such as ZEOSIL 1165.

The Natural Rubber (NR) used in the present invention may be selected from commercially available standard rubbers and the like well known to those skilled in the art.

The carbon black employed in the present invention is commercially available ultra abrasion resistant carbon black N234 well known to those skilled in the art.

The SSBR used in the present invention is commercially available VSL-5025H, SSBR 63, SSBR2560, etc., which are well known to those skilled in the art.

The invention also provides a preparation method of the formula rubber material of the all-steel truck radial tire, which comprises the steps of mixing the raw materials containing the gradient multi-block butadiene-isoprene rubber I to form master batch; mixing the master batch with sulfur II to obtain mixed rubber; and vulcanizing the rubber compound to obtain the rubber composition.

Preferably, the mixing I is carried out in an internal mixer, and the mixing is carried out for 90 to 120s at the temperature of 120 to 140 ℃.

Preferably, the mixing II is carried out on an open mill at a temperature of 50 to 60 ℃. The masterbatch is put into an open mill, sulfur is added after the rubber material is wrapped by a roller, 3/4 cutting knives are respectively arranged on the left side and the right side of the open mill for three times at intervals of 15s, then the roller spacing is adjusted to 0.8mm, the rubber material is pressed into rubber sheets with the thickness of about 2.2mm after being alternately passed through from each end for six times in a longitudinal thinning mode, and then the rubber sheets can be taken out for sample preparation and vulcanization.

Preferably, the vulcanization is carried out at 160-170 ℃ for 10-20 min. And (4) analyzing the physical properties of the molded vulcanized rubber.

The invention provides a high-performance all-steel truck radial tire which is characterized in that the rubber for tire tread, tire side and tire base is a gradient multi-block butadiene-isoprene rubber which has proper branched chain content, the number proportion of side-chain vinyl units, 1, 2-addition units of butadiene and 3, 4-addition units of isoprene is less than 10%, the number proportion of trans-1, 4-addition units of polyisoprene and polybutadiene is higher than 75%, the butadiene-isoprene rubber has wide molecular mass distribution, long chain branching of molecular chains and ordered gradient distribution, and the gradient multi-block butadiene-isoprene rubber aims to improve the melt strength of polymer raw rubber and the processing performance of the polymer raw rubber, and is used for rubber for main parts of radial tires with natural rubber and styrene-butadiene rubber, such as the compatibility between tire base and tire side, tire base and tire tread and tire side. After the whole tire blank is vulcanized, the ageing resistance and the cracking resistance of the composite material between the connecting binding surfaces of all the parts are strengthened, the stress and the buffer impact resistance of the tire body are improved, and the rolling resistance of the tire is reduced; particularly, the composite rubber material has the characteristics of good adhesion with steel wires, aging resistance, winding fatigue resistance and the like, can replace BR or the existing TBIR (the prepared composite material is not aging resistant and easy to crack due to poor compatibility of BR and NR) in the traditional formula, can be used as a base material of a high-performance green tire, and strengthens the connection binding surface of each part after the whole tire blank is vulcanized.

The synthesis method of the butadiene-isoprene rubber containing the gradient multi-block comprises the following specific steps:

1) polymerization reaction: adding a certain amount of n-hexane solvent, a diazo reagent and a regulator of a side chain structural unit into a polymerization kettle, then simultaneously adding a certain amount of butadiene and isoprene into the polymerization kettle, starting stirring, heating the materials in the polymerization kettle to a polymerization initiation temperature by using a hot water bath, adding a certain amount of n-butyl lithium at one time for polymerization reaction of monomer initiation and chain growth, wherein the time required by the copolymerization reaction from the initiation temperature to the highest polymerization temperature is 40-50 min, so that a dilute hexane solution of divinylbenzene is continuously added during the polymerization reaction and the chain growth, the continuous feeding time of the dilute solution is 40-60 min, and after the divinylbenzene is added, the reaction is continued for 20-30 min.

2) End capping reaction: and after the polymerization reaction is finished, adding a certain amount of polar compound which can be condensed with polyisoprene active lithium at the tail end of a polymer molecular chain into the polymerization kettle for end-capping reaction for 15-20 min.

3) And (3) coagulation and drying: and (3) removing the polymerized glue solution from the polymerization kettle, adding necessary antioxidant, uniformly mixing, condensing by using water vapor, and drying to obtain the crude glue.

In the above preparation method, the mass ratio of butadiene to isoprene is (20-80) to (80-20).

In the above production method, the molar ratio of divinylbenzene to alkyllithium is (1.0 to 3.0): 1. Divinyl benzene (DVB) is used as a long-chain and short-chain molecular branching agent containing the gradient butadiene-isoprene rubber, wherein the preferable divinyl benzene accounts for 0.08-0.16% of the total mass of butadiene and isoprene.

In the above preparation method, the diazo reagent is preferably 1, 5-diazobicyclo [4,3,0]]-5-nonene (DBN) or 1, 8-diazobicyclo [5,4,0]-7-undecene (DBU) or a mixture thereof, preferably diazo reagent/NBL (molecular ratio) ═ 05 to 1.6, and more preferably 0.8 to 1.3 of diazo reagent/NBL (molecular ratio), wherein the hindered amine diazo reagent is combined with butyl lithium or active polymer lithium chain, and can effectively prevent the action of fast initiation of lithium-based anionic polymerization monomer and fast growth of polymerization chain, thereby widening the molecular mass distribution fraction of the polymer, and improving the weight-average molecular mass of the polymer by adding DVB branching action for polymer active chain growth, and under the combined action of the diazo reagent and DVB, the molecular mass distribution index M of the polymer is constructed_Wand/Mn is 2.5-3.5, so that the processability of the polymer raw rubber is improved.

In the above production method, the alkyllithium is preferably butyllithium NBL.

In the preparation method, the initiation temperature and the polymerization reaction are within the range of 50-95 ℃, and the higher polymerization temperature is beneficial to improving the addition rate of trans-1, 4.

In the preparation process of the butadiene-isoprene rubber containing the gradient block, Lewis base such as tetrahydrofurfuryl alcohol ethyl ether which is known in the industry is used as a regulator of 1, 2-addition units of butadiene and 3, 4-addition units of isoprene. The concentration of the preferred regulator in a polymerization solvent is 280-400 mg/L, wherein the total content of 1, 2-addition units and 3, 4-addition units in the total conjugated diene units is not less than 75%, and the purpose is that the synthesized butadiene-isoprene rubber and SSBR with high vinyl content are compounded into a tread material with high gripping performance and low rolling resistance; the base and sidewall compounds that work with NR have lower dynamic heat generation.

In the preparation method, the continuous adding time of the divinylbenzene into the anionic polymerization solution system is controlled within 40-80 min, and the polymerization reaction is continued for 20-30 min after the divinylbenzene is added. In the synthesis process of the butadiene-isoprene rubber containing the gradient block, NBL is added into a polymerization kettle once, then dilute DVB solution can be continuously added, and the preferable charging time for continuously adding DVB into the polymerization kettle is 50-60 min; after the DVB is added, the reaction is continued for 20-30 min at the temperature of preferably 90-95 ℃ so as to ensure that a small amount of isoprene in the polymer is completely converted at the later stage.

In the preparation method, the divinyl benzene is diluted by a solvent and then added in a form of dilute solution. The diluent is n-hexane solvent. The purpose of dilution is to control the divinyl benzene to be slowly added, and the dilution degree is adjusted according to actual conditions.

In the above preparation method, the polar capping agent contains at least one element selected from tin, nitrogen and oxygen, and contains a functional group in which at least one of halogen, ketone, acid, amine or ester reacts with active lithium. The polar capping agent of the invention is a polar capping agent commonly found in the prior art. The polar end capping agent is preferably at least one or more of tributyl tin chloride, N' -dimethyl imidazolidinone, trimethyl chlorosilane and other organic matters capable of being added or condensed with active lithium; most preferably one of N, N '-dimethyl imidazolidinone and tributyl tin chloride, or most preferably carbonyl in N, N' -dimethyl imidazolidinone molecule is added with active chain lithium to form [ -O ]^-Li⁺]Then tributyltin chloride and-O are used^-Li⁺Condensation blocking is carried out, the blocking agent preferably being added in an amount of equimolecular mass of the active lithium.

In the preparation method, the temperature of the end-capping reaction is 50-85 ℃ and the time is 15-20 min.

The invention adopts an anionic polymerization method, n-butyllithium is taken as an initiator, a trace diazo reagent is taken as a molecular mass distribution widening agent, tetrahydrofurfuryl alcohol ethyl ether is taken as a microstructure regulator, divinylbenzene is taken as a regulator for branching molecular chains and improving the weight average molecular mass of polymers, a polar compound is taken as an end capping agent, a mixture of butadiene, isoprene and trace divinylbenzene is randomly copolymerized in a polymerization kettle taking hexane as a solvent, and finally the prepared copolymerization glue solution containing active lithium is blocked by polar groups to obtain the gradient multiblock butadiene rubber with the ordered gradient distribution, wherein the content of 3, 4-addition units of the vinyl and polyisoprene of a polybutadiene block is proper, the content of trans-1, 4-addition units is not less than 25 percent, the wide molecular mass distribution is realized, and the long chain branching of the molecular chains is realized.

The diazo reagent adopted by the invention is a hindered amine miaow and has the characteristics of Lewis base, the hindered amine miaow is not only a regulator of the microstructure of a lithium polymer, but also a retarder for initiating and growing a polymerization chain by active lithium, namely the polymerization rate of butadiene or isoprene can be delayed, and the purposes that two monomers of butadiene and isoprene are in slow initiation, initiated active chains and slow growth are achieved. In addition, in the continuous addition polymerization system of the divinylbenzene, the divinylbenzene plays roles of slow branching and long chain branching, can also improve the weight-average molecular mass of the polymer, further broadens the molecular mass distribution and the distribution fraction of the copolymer, simultaneously increases the melt elasticity of the copolymer and the green strength, and is beneficial to the subsequent processing of the green rubber. It should be further noted that because of the particularity of the electron cloud distribution in the molecular structure of divinylbenzene, the polymerization rate of divinylbenzene is much higher than that of butadiene and isoprene, so that divinylbenzene is not suitable for being added to the initiation or polymerization environment at a time, otherwise divinylbenzene will be rapidly homopolymerized or condensed and does not serve the purpose of branching and broadening the molecular weight of the copolymer.

It needs to be further explained that: it is well known to those skilled in the art that butadiene has a higher degree of polymerization than isoprene under normal lithium-based catalysis, as described in the literature ("research on copolymerization of isoprene with tetrahydrofuran as a regulator," gazette et al, high molecular materials at university of chemical industry "). Describes the polymerization rate r when THF/NBL is 0.5_Bd＝2.08，r_IpR is 0.39 with increasing THF_BdContinues to increase r_IpThe decrease continues. In addition, in the US patent US 4451576 it is reported that butadiene can be totally converted under the action of diazo reagent, whereas the conversion of styrene is not higher than 81%. In the polymerization environment of the diazotization reagent, the invention unexpectedly discovers that when the molecular ratio of the diazotization reagent to NBL (butyl lithium) is about 1.4:1, butadiene and isoprene with equal mass are respectively polymerized at 85-95 ℃, and when the polymerization time is 75min, the butadiene can be completely converted, and the conversion rate of the isoprene is 87.4%; when the polymerization time is 90min, the isoprene canAnd (4) carrying out complete conversion. I.e., butadiene is much greater than the isoprene polymerization rate in the polymerization system of the present invention. Firstly initiating and chain extending most of butadiene in the early stage of polymerization, and only initiating a small amount of isoprene, wherein in the later stage of copolymerization reaction, the relative concentration of butadiene is lower, and the relative concentration of isoprene is higher, namely the front segment of a copolymer molecular chain is mainly a polybutadiene block, and random copolymerization of a small amount of isoprene and a large amount of butadiene is doped to form a higher polybutadiene block unit and a trace amount of lower polyisoprene micro-block units; and in the later period of polymerization, the molecular chain end of the copolymer is mainly a longer homopolymerized block unit of polyisoprene. Namely, the butadiene-isoprene copolymer of the present invention belongs to a butadiene-isoprene rubber copolymer with ordered gradient distribution. Such a molecular configuration of the copolymer is beneficial for compatibility with polybutadiene units in natural rubber and solution-polymerized styrene-butadiene rubber molecules.

In the gradient multi-block polybutadiene-isoprene rubber, chain lengths of a butadiene homopolymerized block and an isoprene homopolymerized block in each branched long-chain molecule are different, different sum values of the chain lengths determine molecular mass of the branched chain segment, and different molecular mass distributions and distribution grades of a polymer are reflected.

The butadiene-isoprene rubber containing gradient blocks has a small amount of branching units without divinylbenzene in molecular chains, and some molecular chains contain a plurality of branching units.

In the preparation process of the butadiene-isoprene rubber containing the gradient multiblock, the charge ratio of butadiene, isoprene and divinylbenzene is fixed, butyl lithium is used for initiating a mixed monomer in a hydrocarbon solution, the reaction has the characteristics of continuous initiation, chain extension and long-short chain random branching, simultaneously 1, 2-addition, 3, 4-addition and trans-1, 4-addition are simultaneously carried out in the monomer chain extension, and a copolymer molecular chain has a microblock formed by gradient distribution and polybutadiene and polyisoprene units with a longer block.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

compared with the prior non-functionalized capped general high cis-1, 4-BR, low cis-BR or BR-9000 and rare earth catalytic synthesized BR, the gradient-containing block BIR has wider molecular mass distribution and high melt elasticity, avoids the defect of poor processing performance of the traditional lithium series rubber, and is embodied in that the adhesiveness and the mixing and roll-wrapping performance in the green rubber processing process are obviously improved compared with the lithium series BR with narrow molecular mass distribution; more importantly, the gradient block-containing BIR molecule of the invention has proper trans-1, 4 addition units, and has excellent compatibility (partially similar molecular structure with NR) when being used with natural rubber, and the vulcanized composite rubber has the advantages of flexing crack resistance, crack initiation resistance, crack growth resistance, high elastic recovery, wear resistance, ozone resistance, ultraviolet resistance, ageing resistance and the like.

In addition, the BIR molecule has higher 1, 2-or 3, 4-addition unit and terminal functionalized closure rate, and shows good wet skid resistance and low rolling resistance when being matched with SSBR to be used as a tread rubber; meanwhile, the whole tire also shows low dynamic heat generation in the periodic deformation process.

The invention surprisingly discovers that the physical properties of the vulcanized rubber are not primary and secondary compared with TBIR and NR combined rubber by selecting the lithium series combined rubber containing the gradient blocks BIR and NR in the invention.

The invention also discovers that the selected lithium system containing gradient block BIR and styrene butadiene rubbers such as SSBR and ESBR show excellent compatibility.

The composite rubber materials for the tire tread, the tire side and the tire base part show excellent mutual adhesion, compatibility and homogeneous crosslinking, do not generate phase separation, can be used as a green and environment-friendly high-performance all-steel truck radial tire, and show good comprehensive physical and mechanical properties.

The preparation method of the BIR source and the composite sizing material is simple, can be prepared by utilizing the existing mature process, and is easy to control and industrialize.

Detailed Description

The present invention is illustrated by the following examples, which are not intended to limit the scope or practice of the invention.

In the following examples, Gel Permeation Chromatography (GPC) was used to measure the molecular mass and distribution of IBR dope solution synthesized by polymerization; measuring the physical properties of the vulcanized rubber by adopting an INSTRON tensile machine; the dynamic viscoelastometer is adopted to measure the tan delta value at 60 ℃/0 ℃ to represent the rolling resistance and the ground holding force of the tread rubber of the tire; determining the dynamic heat generation of the vulcanized rubber by adopting a DUNLOP power loss instrument; and (3) measuring the aging performance of the composite rubber material by adopting thermal oxidation aging.

Example 1

Adding 7000mL of n-hexane and 1.5-diazobicyclo [4,3,0] -5-nonene (DBN)1.0mL into a 10-liter polymerization kettle under the protection of nitrogen, then adding 1060g of butadiene and 300g of isoprene into the polymerization kettle under the nitrogen pressure, starting stirring, then heating the polymerization solution to 75 ℃, under the protection of nitrogen and 0.35MPa, then adding 13.5mL of NBL (N-bromosuccinimide) of 0.72mol/L, then dropwise adding 9.5mmol of DVB hexane solution into the polymerization kettle for 45min, and then heating the polymerization reaction material to 95.6 ℃ of maximum temperature after 45min of glue solution, wherein the heating rate is 0.46 ℃/min. And then continuously stirring and reacting for 20min, adding 13mL of N, N' -dimethyl imidazolidinone of 0.7mol/L into the polymerization kettle, and reacting for 15-20 min at the temperature of not higher than 90 ℃ to obtain the catalyst.

And then, removing the polymerization glue solution from the polymerization kettle, adding 3.5g of antioxidant 1076, uniformly mixing, condensing the glue solution by using water vapor, and drying to obtain the polymer glue solution.

As a result, the number average molecular weight Mn of the raw rubber was 14.95X 10⁴The molecular weight distribution index is 2.58; the 1, 2-addition unit content in the polybutadiene unit in the raw rubber is 8.94 percent, and the trans-1, 4-addition unit content in the raw rubber is 76.21 percent; the content of 3, 4-addition units in the polyisoprene units is 8.75 percent, and the content of trans-1, 4-addition units in the polyisoprene units is 74.86 percent; the Mooney viscosity ML of the raw rubber is 51.6; tg was-85.7 ℃.

Example 2

The relevant process conditions in example 1 were kept unchanged except that 0.9mL of DBN was added, the mixed monomer for the first stage consisted of 1100g of butadiene and 350g of isoprene, 12mL of butyllithium was added, 10.8mmol of divinylbenzene was continuously added dropwise, and the continuous addition time was 50 min; and 12mL of N, N' -dimethyl imidazolidinone for lithium end capping of the second active chain.

As a result, the number average molecular weight Mn of the raw rubber was found to be 16.78X 10⁴A molecular weight distribution index of 2.74; the 1, 2-addition unit content and the trans 1, 4-addition unit content in the polybutadiene unit in the raw rubber are 8.43% and 78.56%, respectively; the content of 3, 4-addition units in the polyisoprene units is 6.42 percent, and the content of trans-1, 4-addition units in the polyisoprene units is 81.86 percent; the Mooney viscosity ML of the raw rubber is 58.5; tg was-84.6 ℃.

Example 3

The relevant process conditions in example 2 were kept unchanged except that 1.2mL of DBU was added, the mixed monomer for the first stage consisted of 900g of butadiene and 500g of isoprene, 10mL of butyllithium was added, 11.8mmol of divinylbenzene for continuous dropwise addition, and the continuous dropwise addition time was 48 min. And reacting 10mL of N, N' -dimethyl imidazolidinone for the second-stage active chain lithium end capping at 85-90 ℃ for 20min, and then adding 9mL of 0.7mol/L hexane solution of tributyltin chloride into the polymerization kettle to react at 80-85 ℃ for 20 min.

As a result, the number average molecular weight Mn of the raw rubber was found to be 19.24X 10⁴Molecular weight distribution index 2.86; the 1, 2-addition unit content in the polybutadiene unit in the raw rubber is 7.46 percent, and the trans-1, 4-addition unit content in the raw rubber is 78.94 percent; the content of 3, 4-addition units in the polyisoprene units was 6.23%, and the content of trans 1, 4-addition units was 75.82%; the Mooney viscosity ML of the raw rubber is 62.7; tg was-83.4 ℃.

Example 4

Keeping the relevant process conditions in example 3 unchanged, except that 1.3mL of DBU is added, the mixed monomer for the first stage consists of 800g of butadiene and 600g of isoprene, the polymerization initiation starting temperature is 80 ℃, the highest temperature of polymerization is controlled to be not higher than 100 ℃, 9mL of butyl lithium is added, 12.5mmol of divinylbenzene is continuously added dropwise, and the continuous dropwise adding time is 45 min; 8mL of N, N' -dimethylimidazolidinone for second-stage active chain lithium termination and 8mL of tributyltin chloride in hexane.

As a result, the number average molecular weight Mn of the raw rubber was 21.6X 10⁴The molecular weight distribution index D is 3.12; the 1, 2-addition unit content in the polybutadiene unit in the raw rubber is 4.23%, and the trans-1, 4-addition unit content in the raw rubber is 86.12%; the content of 3, 4-addition units in the polyisoprene units was 5.12%, and the content of trans 1, 4-addition units was 84.56%; the Mooney viscosity ML of the raw rubber is 66.7; tg was-81.8 ℃.

Application example 1 (rubber for tire base)

The gradient block BIR and the load-AlR prepared in the examples 1 to 4 are₃Six samples of TBIR with Mooney viscosity of 62 and BR-9000 prepared by catalysis are respectively matched with NR, and are subjected to mixing and vulcanization according to the formula and the preparation method of the rubber for the base of the tire, wherein the vulcanization temperature is 165 ℃ and the vulcanization time is 15 min. The physical properties of the obtained composite material for the base of all-steel truck radial tire are shown in table 1.

Table 1 physical properties of the composite material for tire base

The formula comprises a butyl rubber NR 20 containing gradient blocks; BIR 45; ESBR 150035; n234 carbon black 60; process oil TDAE 11; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; anti-aging agent RD 3.0; accelerator CZ 1.3; accelerator D1.8; sulfur 1.6

The data in Table 1 show that when the gradient block BIR is respectively compared with TBIR and BR-9000, and the gradient block BIR and TBIR are respectively used together with NR and ESBR, the rubber material for the base part of the tire with high elongation, high hardness, high resilience, low heat generation and aging resistance in the same ratio can be obtained; and the aging performance of the BR-9000 and NR combined glue is obviously reduced.

Application example 2 (rubber for tire side wall)

BIR prepared in example 1, example 2, example 3 and example 4 and supported titanium-AlR₃Six samples of TBIR and BR-9000 prepared by catalysis are respectively matched with NR, and are mixed and vulcanized according to the tire side formula and the preparation method of the invention, wherein the vulcanization temperature is 165 ℃ and the vulcanization time is 15 min. The physical properties of the obtained all-steel truck radial tire side composite material are shown in Table 3.

Table 2 physical properties of the tire side composite

Formula: contains a gradient block butadiene-isoprene rubber BIR 30; ESBR 150070; n234 carbon black 65; NAP-10 rubber oil 12; 2.0 parts of protective wax; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; anti-aging agent RD 3.0; accelerator NS 1.5; accelerator D1.3; 1.8 of sulfur.

From the data in Table 2, it was found that when BIR of the present invention is used in combination with ESBR, the rubber composition for a tire side part has a tensile strength and a hardness higher than those of the rubber composition for a tire side part, a rebound resilience higher than those of the rubber composition for a tire side part, a heat build-up lower than those of the rubber composition for a tire side part, and excellent aging resistance.

Application example 3 (rubber for tire Tread)

Six samples of BIR, TBIR and BR-9000 prepared in example 1, example 2, example 3 and example 4 were compounded with SSBR2560, and kneaded and vulcanized according to the tire tread rubber formulation and preparation method of the present invention at a vulcanization temperature of 165 ℃ for 15 min.

The physical properties of the prepared all-steel load-carrying radial wheel tread composite material are shown in table 3.

Table 3 physical properties of the composite material for the tread portion of the wheel

Formula: an oil-extended SSBR 30; contains a gradient block butadiene-isoprene rubber BIR 30.0; NR 40; 30 parts of white carbon black; carbon black 25; 5.0 parts of zinc oxide; 2.0 parts of stearic acid; si-698.0; an anti-aging agent 40102.0; 1.0 of anti-aging agent RD; 1.0 of protective wax; TDAE 7.0; 1.8 parts of sulfur; promoter CZ 1.7; accelerator D1.3.

From table 3, it is found that the tread rubber of the present invention not only has good physical and mechanical properties, but also exhibits the characteristics of high wet skid resistance coefficient (good wet skid resistance) and low rolling resistance value (low rolling resistance).

Application example 4

The rubber compound for a base portion prepared in application example 1, the rubber compound for a side portion prepared in application example 2, and the rubber compound for a tread prepared in application example 3 were combined, each with a rubber sheet of 5 × 4 × 3mm, and spread in a mold cavity of a vulcanization mold of 15 × 12mm to be vulcanized at a vulcanization temperature of 165 ℃, for 15min, and the physical properties of the rubber sheets of the composite combination after the vulcanized rubber was demolded are shown in table 4.

TABLE 4 physical Properties of the composite vulcanized rubber sheets

It is obvious that the vulcanized rubber prepared by the invention, namely joints of the tire tread and the tire side, the tire tread and the tire base and the tire side part show good adhesion compatibility, and the defects of poor compatibility of the joints of the comparison BR-9000/NR combined rubber and the BIR/SBR and the BIR/NR rubber are undoubtedly exposed.

Namely, the tread, the base and the sidewall of the all-steel truck radial tire prepared by the invention are not torn or dropped under the action of periodic deformation, friction and shearing of the tire, and the invention also aims to solve the problem of the prior art.