A rubber nanocomposite, its preparation and use

Abstract

The present application relates to a kind of rubber nanocomposites, especially relates to a kind of wet mixing rubber masterbatch containing trans-polybutadiene rubber and the preparation method and application of composite material.The composite material is made of the following components by weight parts:20-95 parts of wet mixing rubber masterbatch, 0-20 parts of natural rubber NR, 0-15 parts of butadiene rubber BR, 5-15 parts of trans-polybutadiene rubber TBIR, 0-60 parts of other rubber, 0-30 parts of carbon black, 0.3-5 parts of accelerator, 0.3-8 parts of sulfur, 1-4.5 parts of zinc oxide, 1-9 parts of stearic acid, 1-5 parts of antioxidant, and 0-20 parts of other additives.The wet mixing technology is used in the mixing rubber masterbatch, a large amount of filler and rubber are dispersed first, the masterbatch with good dispersion of filler and additives is prepared, and then other rubber is mixed and vulcanized, to reduce the environmental pollution in preparation.The fatigue resistance and wear resistance of the vulcanized rubber composite material are improved, and the rolling resistance is reduced, which can be applied to the tread, sidewall and upper triangular part of all-steel truck tire, all-rigid or semi-steel passenger car tire, and damping elastic element products.

Description

Technical Field

[0001] This invention relates to the field of rubber, and particularly to a rubber nanocomposite material containing high trans-1,4-butadiene-isoprene copolymer, its wet mixing preparation method, and its uses. Background Technology

[0002] The comfort, safety, and service life of rubber tires have increasingly become the focus of the tire industry. Furthermore, with the increasing demands for energy conservation, emission reduction, carbon emission reduction, and environmental improvement, reducing wear and preventing the generation of fine rubber debris during tire use, and reducing rolling resistance to achieve fuel savings and emission reduction, have become driving forces and directions for the development of the tire rubber industry. Fillers, especially carbon black and silica, are important rubber reinforcing materials and are being added in increasing quantities to tires and other rubber products. However, the ability of fillers to disperse well in rubber products is crucial to their performance. Wet mixing is one method that can provide uniform dispersion of reinforcing fillers.

[0003] Chinese invention patent CN103205001 discloses a method for dispersing fillers in a rubber solution, employing a two-step method of stirring and fine dispersion to improve filler dispersion. This invention does not disclose the preparation of rubber nanocomposites, but only the dispersion of an inorganic material in a rubber solution. Subsequently, Chinese invention patent CN102356120A disclosed a wet mixing and granulation technology and a carbon black-containing wet masterbatch obtained using this technology. Comparative analysis revealed that wet masterbatch granulated with wet carbon black exhibits improved rubber strength and abrasion resistance compared to ungranulated masterbatch.

[0004] Furthermore, Chinese invention patent CN102725322A discloses a method for preparing silica aqueous dispersion using silica modified with divalent metal elements, mixing natural rubber latex with the silica-doped aqueous dispersion, and then obtaining a dried, coagulated latex to obtain masterbatch. Chinese invention patent CN103113597 discloses a continuous manufacturing method for wet-process rubber masterbatch, which expands the application range of rubber and fillers by employing a new rubber coagulation technology. Subsequently, Chinese invention patents CN103224659 and CN103419293 report an integrated continuous production method for wet-process rubber compounding, which involves mixing carbon black or silica with a rubber solution and then coagulating the mixture to obtain a wet-process compound. However, this method uses solid fillers to directly mix with the rubber solution, which cannot achieve efficient mixing.

[0005] The existing patented technologies mentioned above either use water as a dispersion medium or their coagulation process takes place in an aqueous phase, resulting in the generation of large amounts of wastewater with high COD content, increasing the potential for environmental pollution or raising wastewater treatment costs. The wet-process rubber masterbatch preparation process described in this invention overcomes the drawback of existing patented technologies requiring large amounts of water during the coagulation process. Furthermore, it employs a two-step mixing process to further improve the good dispersion of fillers, achieving the preparation of a greener rubber nanocomposite material. Summary of the Invention

[0006] To address the shortcomings of existing patented technologies, one objective of this invention is to provide a rubber nanocomposite material containing a high trans-butadiene-isoprene copolymer. Another objective of this invention is to provide a method for preparing this rubber nanocomposite material and its applications. The rubber nanocomposite material of this invention, containing a high trans-butadiene-isoprene copolymer, comprises the following components by weight: 20-95 parts wet-process rubber masterbatch, 0-20 parts natural rubber, 0-15 parts cis-butadiene rubber, 5-15 parts trans-butadiene-pentadiene rubber, 0-60 parts other rubbers, 0-30 parts carbon black, 0.3-5 parts accelerator, 0.3-8 parts sulfur, 1-10 parts zinc oxide, 1-9 parts stearic acid, 1-10 parts antioxidant, and 0-20 parts other additives.

[0007] The wet-process rubber masterbatch of the present invention is composed of the following components in parts by weight: 45-90 parts natural rubber, 0-25 parts cis-butadiene rubber, 5-50 parts trans-butadiene-pentadiene rubber, 50-120 parts silica, 0.5-20 parts coupling agent, and 0.5-3 parts antioxidant. The trans-butadiene-pentadiene rubber is a high-trans-1,4-butadiene-isoprene copolymer, with a butadiene monomer molar content of 2-70% and a trans-1,4-structure molar content greater than 90%.

[0008] This invention provides a method for preparing rubber nanocomposite materials, comprising the following steps:

[0009] (1) Dissolve 45-90 parts of natural rubber, 0-25 parts of cis-butadiene rubber, and 5-50 parts of trans-butadiene rubber in a solvent at a dissolution temperature of 20-70°C for 0.1-5 hours to prepare a rubber solution with a solid content of 5-40 wt%. Add 50-120 parts of silica, 0.5-20 parts of coupling agent, and 0.5-3 parts of antioxidant to the above rubber solution. Stir at a speed of 5-1500 rpm for 0.1-10 hours to obtain a rubber-filler-auxiliary dispersion in which fillers and additives are uniformly dispersed. Dry the above rubber-filler-auxiliary dispersion by a screw de-devouring process to obtain a wet-mixed rubber masterbatch.

[0010] (2) Add 20-95 parts of wet-mixed rubber masterbatch from step (1), 0-20 parts of natural rubber, 0-15 parts of butadiene rubber, 5-15 parts of trans-butadiene rubber, and 0-60 parts of other rubbers to a mixer. Add 1-10 parts of zinc oxide, 1-9 parts of stearic acid, 1-10 parts of antioxidant, 0-30 parts of carbon black, and 0-20 parts of other additives. Perform a first-stage mixer, controlling the mixer temperature at 50-170℃. After the mixer time reaches any point between 3 and 30 minutes, discharge the rubber to obtain a first-stage mixer. Then, control the mixer temperature at 60-80℃, add the first-stage mixer, 0.3-5 parts of accelerator, and 0.3-8 parts of sulfur, and perform a second-stage mixer. After the mixer time reaches any point between 2 and 10 minutes, discharge the rubber to obtain a rubber nanocomposite material.

[0011] Other additives involved in this invention include, but are not limited to, one or more of paraffin wax, environmentally friendly processing oil, aromatic oil, cycloalkane oil, dispersant, compatibilizer, and tackifying resin, used in combination.

[0012] In this invention, a coupling agent is used, which is one or a combination of two of the following: bis-[γ-(triethoxysilyl)propyl]tetrasulfide, 3-thiocyanopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxysilane, 3-octanoylthio-1-propyldiethoxysilane, [2-(4-chloromethylphenyl)ethyl]-diethoxysilane, (3-mercaptopropyl)-bis[tetrazylpolyoxyvinyl]-ethoxysilane, zirconate coupling agent, titanate coupling agent, and nitro coupling agent; the antioxidant is selected from one or two or more of amine antioxidants and phenolic antioxidants; the accelerator includes one or two or more of thiazoles, sulfenamides, thiurams, sulfocarbamates, diphenylguanidine accelerators, and hexamethylenetetramine.

[0013] In preparing the wet-process compound rubber masterbatch, the solvent used in this invention is one of gasoline, hydrogenated gasoline, hexane, heptane, pentane, benzene, toluene, xylene, cyclohexane, tetrahydrofuran, carbon tetrachloride, dichloroethane, trichloroethane, chloroform, and dichloromethane.

[0014] Compared with traditional methods, the rubber nanocomposite material of the present invention improves the stiffness and modulus of the wet compound by adding trans-butadiene rubber (TBIR) to the compound. The resulting vulcanized rubber exhibits improved fatigue resistance, improved wear resistance, and reduced rolling resistance.

[0015] In the rubber nanocomposite material of the present invention, the other rubbers are one or two of solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, chloroprene rubber, butyl rubber, brominated butyl rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene propylene diene monomer (EPDM) rubber, acrylic rubber, fluororubber, and silicone rubber.

[0016] The beneficial effects of this invention are that by using a wet-mixing method to prepare a wet-mixed rubber masterbatch, which disperses a large amount of filler, and then applying it to the manufacture of the tread, sidewall, and upper triangular parts of all-steel truck tires and all-steel or semi-steel passenger car tires, it can improve tire service life, reduce rolling resistance, and achieve the goals of fuel saving and carbon emission reduction. When applied to the manufacture of vibration-damping elastic element products, it improves the dynamic fatigue performance and dynamic and static stiffness of vibration-damping elements, extends service life, and enhances safety. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to specific embodiments, which will help in understanding the present invention. However, the present invention is not limited to the following embodiments, and the scope of the present invention should be determined by the claims.

[0018] raw materials

[0019] Natural rubber NR, grade SCR WF, from Jinshui Processing Plant of China National Rubber Industry Corporation; butadiene rubber BR, grade BR9000, from Qilu Petrochemical Co., Ltd.; trans-butadiene-pentadiene rubber TBIR, TBIR-20, butadiene content 20mol%, trans-1,4- content 95mol%; trans-butadiene-pentadiene rubber TBIR, TBIR-40, butadiene content 40mol%, trans-1,4- content 95mol%, from Shandong Huaju Polymer Materials Co., Ltd.; solution-polymerized styrene-butadiene rubber SSBR, grade BUNAVSL 5025-2HM, from Lanxess Chemicals (China) Co., Ltd.; chloroprene rubber CR, nitrile rubber NBR, emulsion styrene-butadiene rubber ESBR, silica 7000GR, carbon black N234, coupling agent bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si69), and other additives are all commercially available industrial products.

[0020] Example 1

[0021] Preparation of wet-process compound rubber masterbatch: Rubber NR, BR, and TBIR were added to hexane according to the proportions in Table 1 to prepare a rubber solution with a solid content of 30 wt%. The stirring temperature was 50℃, the stirring speed was 50 rpm, and the stirring time was 2 hours. Silica, Si-69, and antioxidant 4010NA were added to the rubber solution according to the formula in Table 1. The stirring speed was 150 rpm, and the stirring time was 2 hours. After obtaining the rubber-filler and auxiliary agent dispersion, it was devolatilized through a screw extruder and dried to obtain the wet-process compound rubber masterbatch for later use.

[0022] Preparation of rubber nanocomposites: Wet-process rubber masterbatch, NR, BR, TBIR, other rubbers, and additives other than the vulcanization system were added to an internal mixer according to the proportions in Table 1. The mixing temperature was controlled at 155℃, and the mixture was mixed for 6 minutes. The mixture was then discharged to obtain a first-stage internally mixed rubber. Then, the internal mixer temperature was adjusted to 70℃, and the first-stage internally mixed rubber, vulcanization accelerator, and sulfur were added. After mixing for 3 minutes, the mixture was discharged to obtain the rubber nanocomposites. After vulcanization, the vulcanized rubber was obtained, and its performance was tested. The results are shown in Table 1.

[0023] Examples 2-6

[0024] The processing steps were the same as in Example 1, following the formulation in Table 1. After vulcanization, vulcanized rubber was obtained, and its performance was tested. The results are shown in Table 1.

[0025] Comparative Example 1

[0026] According to the formulation in Table 1, NR, BR, TBIR, fillers, and additives other than those in the vulcanization system were added to an internal mixer. The mixing temperature was controlled at 100-155℃, and the mixer was mixed for 12 minutes. The rubber was then discharged to obtain a first-stage internally mixed rubber. Then, the internal mixer temperature was adjusted to 70℃, and the first-stage internally mixed rubber, vulcanization accelerator, and sulfur were added. After mixing for 3 minutes, the rubber was discharged to obtain a rubber nanocomposite material. After vulcanization, the vulcanized rubber was obtained, and its performance was tested. The results are shown in Table 1.

[0027] Table 1. Formulations and performance of the examples and comparative examples (formulations in the table are in parts).

[0028]

[0029] The performance comparisons of the examples and comparative examples show that the formulation using wet-process compounded rubber as the masterbatch has improved filler dispersibility, reduced rolling resistance, increased fatigue life, and improved wear resistance.

Claims

1. A rubber nanocomposite material, characterized in that, The composite material comprises the following components by weight: 20-95 parts wet-process rubber masterbatch, 0-20 parts natural rubber, 0-15 parts butadiene rubber, 5-15 parts trans-butadiene-pentadiene rubber, 0-60 parts other rubbers, 0-30 parts carbon black, 0.3-5 parts accelerator, 0.3-8 parts sulfur, 1-10 parts zinc oxide, 1-9 parts stearic acid, 1-10 parts antioxidant, and 0-20 parts other additives. The wet-process rubber masterbatch is composed of the following components by weight: 45-90 parts natural rubber, 0-25 parts cis-butadiene rubber, 5-50 parts trans-butadiene-pentadiene rubber, 50-120 parts silica, 0.5-20 parts coupling agent, and 0.5-3 parts antioxidant. The rubber nanocomposite material is prepared using the following steps: (1) Dissolve 45-90 parts of natural rubber, 0-25 parts of cis-butadiene rubber, and 5-50 parts of trans-butadiene rubber in a solvent at a dissolution temperature of 20-70℃ and a dissolution time of 0.1-5 hours to prepare a rubber solution with a solid content of 5-40 wt%. Add 50-120 parts of silica, 0.5-20 parts of coupling agent, and 0.5-3 parts of antioxidant to the above rubber solution. Stir at a speed of 5-1500 rpm for 0.1-10 hours to obtain a rubber-filler-auxiliary dispersion in which fillers and additives are uniformly dispersed. Dry the above rubber-filler-auxiliary dispersion by a screw de-devouring process to obtain a wet-mixed rubber masterbatch. (2) Add 20-95 parts of wet-mixed rubber masterbatch, 0-20 parts of natural rubber, 0-15 parts of cis-butadiene rubber, 5-15 parts of trans-butadiene rubber, and 0-60 parts of other rubbers from step (1) to a mixer, add 1-10 parts of zinc oxide, 1-9 parts of stearic acid, 1-10 parts of antioxidant, 0-30 parts of carbon black, and 0-20 parts of other additives, and carry out a first-stage mixing, controlling the mixing temperature at 50-170℃; when the mixing time reaches any point between 3 and 30 minutes, discharge the rubber to obtain a first-stage mixed rubber; then control the mixer temperature at 60-80℃, add the first-stage mixed rubber, 0.3-5 parts of accelerator, and 0.3-8 parts of sulfur, and carry out a second-stage mixing, when the mixing time reaches any point between 2 and 10 minutes, discharge the rubber to obtain a rubber nanocomposite material.

2. The rubber nanocomposite material according to claim 1, characterized in that, The trans-butadiene-isoprene rubber is a high trans-1,4-butadiene-isoprene copolymer, with a butadiene monomer unit molar content of 2-70% and a trans-1,4-structure molar content greater than 90%.

3. The rubber nanocomposite material according to claim 1 or 2, characterized in that, The other additives mentioned are one or more of the following: paraffin wax, environmentally friendly processing oil, aromatic oil, cycloalkane oil, dispersant, compatibilizer, and tackifying resin, used in combination.

4. The rubber nanocomposite material according to claim 1 or 2, characterized in that, The coupling agent is one or a combination of two of the following: bis-[γ-(triethoxysilyl)propyl]tetrasulfide, 3-thiocyanopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxysilane, 3-octanoylthio-1-propyldiethoxysilane, [2-(4-chloromethylphenyl)ethyl]-diethoxysilane, (3-mercaptopropyl)-bis[tetrazylpolyoxyvinyl]-ethoxysilane, zirconate coupling agent, titanate coupling agent, and nitro coupling agent; the antioxidant is selected from one or two or more of amine antioxidants and phenolic antioxidants; the accelerator includes one or two or more of thiazoles, sulfenamides, thiurams, sulfocarbamates, diphenylguanidine accelerators, and hexamethylenetetramine.

5. The rubber nanocomposite material according to claim 1, characterized in that, The solvent is one of gasoline, hydrogenated gasoline, hexane, heptane, pentane, benzene, toluene, xylene, cyclohexane, tetrahydrofuran, carbon tetrachloride, dichloroethane, trichloroethane, chloroform, and dichloromethane.

6. The rubber nanocomposite material according to claim 1, characterized in that, The other rubbers mentioned are one or two of solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, chloroprene rubber, butyl rubber, brominated butyl rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene propylene diene monomer (EPDM) rubber, acrylic rubber, fluororubber, and silicone rubber.

7. The rubber nanocomposite material according to claim 1, characterized in that, The composite material comprises the following components by weight: 50 parts wet-process rubber masterbatch, 40 parts styrene-butadiene rubber, 10 parts trans-butadiene-pentadiene rubber, 20 parts carbon black, 0.6 parts accelerator, 2.1 parts sulfur, 3.5 parts zinc oxide, 1.8 parts stearic acid, and 2.8 parts antioxidant. The wet-process compound masterbatch is composed of the following components by weight: 85 parts natural rubber, 15 parts trans-butadiene rubber, 75 parts silica, 7.5 parts coupling agent, and 2 parts antioxidant.

8. The rubber nanocomposite material according to claim 1, characterized in that, The composite material comprises the following components by weight: 40 parts wet-process rubber masterbatch, 10 parts trans-butadiene rubber, 50 parts chloroprene rubber, 20 parts carbon black, 0.6 parts accelerator, 2.2 parts sulfur, 3.7 parts zinc oxide, 1.9 parts stearic acid, and 3 parts antioxidant. The wet-process compound masterbatch is composed of the following components by weight: 90 parts natural rubber, 5 parts cis-butadiene rubber, 5 parts trans-butadiene-pentadiene rubber, 55 parts silica, 5.5 parts coupling agent, and 2 parts antioxidant.

9. The rubber nanocomposite material according to claim 1, characterized in that, It is used in the manufacture of treads, sidewalls, and upper triangular parts of all-steel truck tires, all-steel or semi-steel passenger car tires, as well as vibration damping elastic element products.

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