Multilayer solid tire and processing method thereof

Abstract

The invention belongs to the technical field of rubber tires, and particularly relates to a multi-layer solid tire and a processing method thereof. The rubber material with high content of the functionalized hollow glass beads is used as the center layer of the tire, the rubber material with low content of the functionalized hollow glass beads is used as the base layer and the outer layer of the tire, and the functionalized hollow glass beads can effectively reduce the consumption of white carbon black and reduce the weight of the center of the tire; the rubber molecular chains bonded on the surfaces of the hollow glass beads ensure that the hollow glass bead filler has good elasticity and toughness, so that the middle part of the tire has relatively small weight and also has good elasticity and buffering power, the friction loss during running of a vehicle is reduced, the running time of the vehicle is prolonged, and the energy consumption is reduced. In the vulcanizing process of the tire blank, the rubber molecular chains on the surfaces of the hollow glass beads and the nano silicon dioxide can be cross-linked and combined together, so that the compactness and binding density of the tire matrix are improved, the heat conduction capability of the rubber tire is further improved, and the flexural temperature rise of the tire is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of rubber tires, and particularly relates to a multi-layer solid tire and a processing method thereof. Background Art

[0002] With the progress of society and the need for production operation safety guarantee, people have put forward higher requirements for the use safety performance of some special vehicles such as engineering vehicles and rescue vehicles applied to extremely harsh environments and complex road conditions. Although traditional pneumatic tires have advantages such as shock absorption and comfort, in harsh environments, pneumatic tires are prone to problems such as air leakage and tire blowout, and their safety performance cannot meet the requirements. Therefore, solid tires have been developed. The carcass of a solid tire is solid, without an inner tube and an airtight layer, and does not need to be inflated. Solid tires have advantages such as high elasticity, good wear resistance, low maintenance cost, and long service life. The processing method of solid tires is as follows: First, the rubber material is processed into rubber strips, and then the rubber strips are wound and laminated on the tire skeleton. The winding layers and thickness of the rubber strips can be adjusted according to the specific use requirements of the tire. After winding, a tire blank is obtained. Finally, the tire blank is put into a tire mold for vulcanization to obtain a solid tire. In order to improve the overall performance of the tire, rubber materials with different formulations can be compounded to form different rubber layers to play different roles and optimize the performance of the tire.

[0003] At present, when processing solid rubber tires, carbon black and silica are often used for reinforcement. However, their surfaces contain hydroxyl groups, and their affinity with rubber is poor, resulting in particle agglomeration and unable to exert a good reinforcement effect. By modifying the surface of the reinforcing filler, although the dispersion degree of the filler in the rubber matrix can be improved and particle agglomeration can be reduced, the bonding force between the reinforcing filler and the rubber matrix is weak, resulting in poor mechanical and mechanical properties of the rubber material and reduced safety. And the reinforcing filler will cause an increase in tire load, resulting in more ineffective kinetic energy dissipation during movement and affecting the energy utilization rate. Summary of the Invention

[0004] Aiming at the above problems, the present invention provides a multi-layer solid tire and a processing method thereof, which are used to solve the problems that the bonding force between the reinforcing filler and the rubber matrix in the current solid tire is weak, resulting in poor mechanical and mechanical properties of the rubber material and low safety.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A processing method of a multi-layer solid tire includes the following steps:

[0007] (1) React a borate acyl chloride compound with a terminal amino nitrile rubber to obtain a borate-block nitrile rubber; the acrylonitrile content of the terminal amino nitrile rubber is 10-18%, the amino equivalent is 900-1200, and the structure of the borate acyl chloride compound is as follows:

[0008]

[0009] Among them, R is n-octyl, hexyl, cyclohexyl or 2-phenylethyl;

[0010] (2) React the borate-block nitrile rubber with double-bond modified hollow glass microspheres to obtain functionalized hollow glass microspheres; the average particle size of the double-bond modified hollow glass microspheres is 25-40 μm;

[0011] (3) React the borate-block nitrile rubber with double-bond modified nano-silica to obtain functionalized nano-silica;

[0012] (4) Wind the first rubber strip around the tire carcass to form a first rubber winding layer, then wind the second rubber strip around the first rubber winding layer to form a second rubber winding layer, and then wind the first rubber strip around the second rubber winding layer to form a third rubber winding layer to obtain a tire blank. Finally, put the tire blank into a solid tire mold for vulcanization treatment to obtain a multi-layer solid tire; the first rubber strip is made by kneading and rolling the following components in parts by mass: 100-115 parts of styrene-butadiene rubber, 15-25 parts of cis-butadiene rubber, 12-16 parts of functionalized hollow glass microspheres, 80-90 parts of functionalized nano-silica, 5-7 parts of carbon black, 3-4.5 parts of zinc oxide, and 2.5-3.5 parts of sulfur; the second rubber strip is made by kneading and rolling the following components in parts by mass: 100-115 parts of styrene-butadiene rubber, 15-25 parts of cis-butadiene rubber, 20-25 parts of functionalized hollow glass microspheres, 65-75 parts of functionalized nano-silica, 5-7 parts of carbon black, 4-5 parts of zinc oxide, and 3-4 parts of sulfur.

[0013] Preferably, the preparation method of the borate acyl chloride compound is as follows: React diethanolamine borate with trimellitic anhydride to obtain a borate carboxylic acid compound, and then react the borate carboxylic acid compound with thionyl chloride to obtain a borate acyl chloride compound; the diethanolamine borate is n-octyl diethanolamine borate, cyclohexyl diethanolamine borate, 2-phenylethyl-1-diethanolamine borate or N-hexyl diethanolamine borate; the reaction temperature of the diethanolamine borate and trimellitic anhydride is 75-85 °C, the time is 3-5 h, and the molar ratio of the diethanolamine borate to trimellitic anhydride is 1:1; the mass ratio of the borate carboxylic acid compound to thionyl chloride is 1:4-6.

[0014] Preferably, the molar ratio of the amino group in the terminal amino group nitrile rubber to the acyl chloride group in the borate acyl chloride compound is 1:1.05 - 1.1.

[0015] Preferably, the mass ratio of the borate block nitrile rubber to the double bond modified hollow glass microspheres is 1:2 - 3. The catalyst during the reaction is (1,3 - bis(2,4,6 - trimethylphenyl)-2 - imidazolidinylidene)dichloride(o - isopropoxybenzylidene)ruthenium. The mass of the catalyst is 1 - 1.5% of the mass of the borate block nitrile rubber. The reaction temperature is 50 - 60 °C and the time is 1 - 2 h.

[0016] Preferably, the double bond modified hollow glass microspheres are prepared by reacting hollow glass microspheres and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:2 - 3.

[0017] Preferably, the mass ratio of the borate block nitrile rubber to the double bond modified nano - silica is 1:3.5 - 5. The catalyst during the reaction is (1,3 - bis(2,4,6 - trimethylphenyl)-2 - imidazolidinylidene)dichloride(o - isopropoxybenzylidene)ruthenium. The mass of the catalyst is 1 - 1.5% of the mass of the borate block nitrile rubber. The reaction temperature is 50 - 60 °C and the time is 3 - 4 h.

[0018] Preferably, the double bond modified nano - silica is prepared by reacting nano - silica and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:4 - 6.

[0019] Preferably, the thickness of the first rubber strip and the second rubber strip is 1.5 - 3 cm. The processing method of the multi - layer solid tire further includes the following steps: heating the first rubber strip winding layer to 110 - 115 °C, keeping warm for 5 - 8 min for pre - vulcanization, then winding the second rubber strip on the pre - vulcanized first rubber winding layer to form a second rubber winding layer, then heating the second rubber winding body to 110 - 115 °C, keeping warm for 10 - 14 min for pre - vulcanization, and then winding the first rubber strip on the pre - vulcanized second rubber winding layer to form a third rubber winding layer. The thickness ratio of the first rubber winding layer, the second rubber winding layer, and the third rubber winding layer is 0.5 - 0.8:1.5 - 2:1.2 - 1.7.

[0020] Preferably, the temperature of the vulcanization treatment is 145 - 155 °C, the pressure is 6 - 9 MPa, and the time is 25 - 40 min.

[0021] A multi - layer solid tire processed by the processing method of the multi - layer solid tire as described above.

[0022] Compared with the prior art, the beneficial effects of the multi - layer solid tire of the present invention are as follows:

[0023] (1) The present invention uses hollow glass microspheres modified with borate block nitrile rubber and nano-silica as fillers for tire rubber, which can effectively improve the mechanical properties of rubber and tires. The nitrile rubber chain segments bonded to the surface of the fillers can chemically bond with the rubber molecular chains in the rubber matrix during the vulcanization process, improving the bonding strength between the fillers and the matrix, avoiding the agglomeration of fillers, improving the dispersion uniformity of fillers, and further effectively improving the mechanical properties of rubber. In addition, the borate chain segments chemically bonded to the surface of the fillers have a cyclic structure with a large steric hindrance, which can further hinder the agglomeration between fillers, ensure an appropriate spacing between fillers, and the cyclic borate can form a coordination bond with nitrogen atoms, improving the bonding force between fillers and between fillers and the rubber matrix, and further improving the comprehensive properties of rubber.

[0024] (2) The present invention uses a rubber material with a higher content of functionalized hollow glass microspheres as the center layer of the tire, and a rubber material with a lower content of functionalized hollow glass microspheres as the base layer and outer layer of the tire. The functionalized hollow glass microspheres can effectively reduce the dosage of silica, reduce the weight of the tire center. The rubber molecular chains bonded to the surface of the hollow glass microspheres ensure that the hollow glass microsphere fillers have good elasticity and toughness, so that the middle part of the tire has both a smaller weight and good elasticity and buffering force, thereby reducing the frictional loss during vehicle driving, increasing the running time of the vehicle, and reducing energy consumption. During the vulcanization process of the tire blank, the rubber molecular chains on the surfaces of the hollow glass microspheres and nano-silica can crosslink and bond together, improving the compactness and bonding density of the tire matrix, and further improving the heat conduction ability of the rubber tire and reducing the flex temperature rise of the tire. Description of the Drawings

[0025] Figure 1 1H NMR spectrum of the borate acyl chloride compound prepared in Example 1 of the present invention. Detailed Embodiments

[0026] In order to enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below in combination with embodiments. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0027] Example 1

[0028] The processing method of the multi-layer solid tire in this example includes the following steps:

[0029] (1) Add dioctyl borate diethanolamine ester, trimellitic anhydride and carbon tetrachloride into a reaction kettle, heat to 75 °C, stir and reflux for 3 h, and remove carbon tetrachloride by vacuum distillation to obtain a borate carboxylic acid compound. Among them, the molar ratio of dioctyl borate diethanolamine ester to trimellitic anhydride is 1:1, and the mass of carbon tetrachloride is 50% of the mass of dioctyl borate diethanolamine ester.

[0030] The structure of dioctyl borate diethanolamine ester is as follows:

[0031]

[0032] The structure of the borate carboxylic acid compound is as follows:

[0033]

[0034] (2) Add the borate carboxylic acid compound and thionyl chloride with a mass ratio of 1:4 into a reaction kettle, heat to reflux, stir and reflux for 6 h to obtain a borate acyl chloride compound (the 1H NMR spectrum of the borate acyl chloride compound is as shown in Figure 1 ); the structure of the borate acyl chloride compound is as follows:

[0035]

[0036] (3) Add terminal amino nitrile rubber (acrylonitrile content is 18%, amino equivalent is 900) and chloroform into a reaction kettle, stir evenly to obtain a rubber solution with a mass fraction of 35%; then cool the materials in the reaction kettle to -5 °C, and under stirring conditions, dropwise add the chloroform solution (mass fraction is 50%) of the borate acyl chloride compound into the reaction kettle. After the dropping is completed, add triethylamine into the reaction kettle, then heat the materials in the reaction kettle to room temperature, continue to stir and react for 3 h, filter, and rotary evaporate the filtrate to obtain a borate-block nitrile rubber. Among them, the molar ratio of the amino group in the terminal amino nitrile rubber to the acyl chloride group in the borate acyl chloride compound is 1:1.05, and the molar ratio of the borate acyl chloride compound to triethylamine is 1:2.2.

[0037] (4) Add hollow glass microspheres (average particle size is 25 μm) and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:2 into ethanol, disperse evenly, heat to 80 °C, stir and reflux for 25 h, filter, wash the filter cake with ethanol, and dry to obtain double-bond modified hollow glass microspheres; the mass of ethanol is 5 times the sum of the masses of hollow glass microspheres and γ-(methacryloyloxy)propyltrimethoxysilane.

[0038] (5) The borate-block nitrile rubber is added to chloroform and fully dissolved to obtain a rubber solution with a mass fraction of 10%. Then, the catalyst and double-bond modified hollow glass microspheres are added to the rubber solution, ultrasonically dispersed evenly, heated to 50 °C, stirred and refluxed for 1 h, cooled to room temperature, filtered, and the filter cake is washed with chloroform and dried to obtain functionalized hollow glass microspheres. Among them, the mass ratio of the borate-block nitrile rubber to the double-bond modified hollow glass microspheres is 1:2, the catalyst is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst is 1% of the mass of the borate-block nitrile rubber.

[0039] (6) Nanometer silicon dioxide and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:4 are added to ethanol, dispersed evenly and then heated to 80 °C, stirred and refluxed for 25 h, filtered, and the filter cake is washed with ethanol and dried to obtain double-bond modified nanometer silicon dioxide; the mass of ethanol is 7 times the sum of the masses of nanometer silicon dioxide and γ-(methacryloyloxy)propyltrimethoxysilane.

[0040] (7) The borate-block nitrile rubber is added to chloroform and fully dissolved to obtain a rubber solution with a mass fraction of 10%. Then, the catalyst and double-bond modified nanometer silicon dioxide are added to the rubber solution, ultrasonically dispersed evenly, heated to 50 °C, stirred and refluxed for 3 h, cooled to room temperature, filtered, and the filter cake is washed with chloroform and dried to obtain functionalized nanometer silicon dioxide. Among them, the mass ratio of the borate-block nitrile rubber to the double-bond modified nanometer silicon dioxide is 1:3.5, the catalyst is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst is 1% of the mass of the borate-block nitrile rubber.

[0041] (8) 100 parts by mass of styrene-butadiene rubber and 15 parts by mass of cis-butadiene rubber are added to a mixer, heated to 90 °C and kneaded for 10 min. Then, 12 parts by mass of functionalized hollow glass microspheres, 80 parts by mass of functionalized nanometer silicon dioxide and 5 parts by mass of carbon black N330 are added, and kneading is continued for 5 min. Then, the temperature is lowered to 60 °C, 3 parts by mass of zinc oxide and 2.5 parts by mass of sulfur are added, and kneading is continued for 45 min to obtain the first rubber material.

[0042] (9) 100 parts by mass of styrene-butadiene rubber and 15 parts by mass of cis-butadiene rubber are added to a mixer, heated to 90 °C and kneaded for 10 min. Then, 20 parts by mass of functionalized hollow glass microspheres, 65 parts by mass of functionalized nanometer silicon dioxide and 5 parts by mass of carbon black N330 are added, and kneading is continued for 5 min. Then, the temperature is lowered to 60 °C, 4 parts by mass of zinc oxide and 3 parts by mass of sulfur are added, and kneading is continued for 45 min to obtain the second rubber material.

[0043] (10) Heat the first rubber material to 100 °C, then roll it through a rolling machine to form a first rubber strip with a thickness of 1.5 cm. Then wind the first rubber strip around the tire skeleton to form a first rubber winding layer. The first rubber winding layer and the tire skeleton form a first rubber winding body. Heat the first rubber winding body to 110 °C and keep it warm for 5 min to pre-vulcanize the first rubber winding layer. Heat the second rubber material to 100 °C, then roll it through a rolling machine to form a second rubber strip with a thickness of 1.5 cm. Then wind the second rubber strip around the pre-vulcanized first rubber winding layer to form a second rubber winding layer. The second rubber winding layer, the pre-vulcanized first rubber winding layer and the tire skeleton form a second rubber winding body. Heat the second rubber winding body to 110 °C and keep it warm for 10 min to pre-vulcanize the second rubber winding layer. Wind the first rubber strip around the pre-vulcanized second rubber winding layer to form a third rubber winding layer. The third rubber winding layer, the pre-vulcanized second rubber winding layer and the pre-vulcanized first rubber winding layer form a tire blank. The thickness ratio of the first rubber winding layer, the second rubber winding layer and the third rubber winding layer is 0.5:1.5:1.2. Finally, put the tire blank into a solid tire mold and carry out vulcanization treatment to obtain a multi-layer solid tire. The temperature of the vulcanization treatment is 145 °C, the pressure is 6 MPa, and the time is 25 min.

[0044] Example 2

[0045] The processing method of the multi-layer solid tire in this example includes the following steps:

[0046] (1) Add n-octyl borate diethanolamine ester, trimellitic anhydride and carbon tetrachloride into a reaction kettle, heat to 80 °C, stir and reflux for 4 h, and remove carbon tetrachloride by reduced pressure distillation to obtain a borate carboxylic acid compound. Among them, the molar ratio of n-octyl borate diethanolamine ester to trimellitic anhydride is 1:1, and the mass of carbon tetrachloride is 55% of the mass of n-octyl borate diethanolamine ester.

[0047] The structure of n-octyl borate diethanolamine ester is as follows:

[0048]

[0049] The structure of the borate carboxylic acid compound is as follows:

[0050]

[0051] (2) Add the borate carboxylic acid compound and thionyl chloride with a mass ratio of 1:5 into a reaction kettle, heat to reflux, stir and reflux for 7 h to obtain a borate acyl chloride compound; the structure of the borate acyl chloride compound is as follows:

[0052]

[0053] (3) Add the terminal amino group nitrile rubber (acrylonitrile content is 10%, amino equivalent is 1200) and chloroform into the reaction kettle, stir evenly to obtain a rubber solution with a mass fraction of 40%; then cool the materials in the reaction kettle to -2 °C, and under stirring conditions, drip the chloroform solution (mass fraction is 55%) of the borate acyl chloride compound into the reaction kettle. After the dripping is completed, add triethylamine into the reaction kettle, then heat the materials in the reaction kettle to room temperature, continue stirring and reacting for 4 h, filter, and rotary evaporate the filtrate to obtain the borate block nitrile rubber. Among them, the molar ratio of the amino group in the terminal amino group nitrile rubber to the acyl chloride group in the borate acyl chloride compound is 1:1.08, and the molar ratio of the borate acyl chloride compound to triethylamine is 1:2.3.

[0054] (4) Add hollow glass microspheres (average particle size is 30 μm) and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:2.5 into ethanol, disperse evenly and then heat to 82 °C, stir and reflux for 28 h, filter, wash the filter cake with ethanol, and dry to obtain double bond modified hollow glass microspheres; the mass of ethanol is 5.5 times the sum of the masses of the hollow glass microspheres and γ-(methacryloyloxy)propyltrimethoxysilane.

[0055] (5) Add the borate block nitrile rubber into chloroform, fully dissolve it to obtain a rubber solution with a mass fraction of 12%; then add the catalyst and the double bond modified hollow glass microspheres into the rubber solution, ultrasonically disperse evenly, heat to 55 °C, stir and reflux for 1.5 h, cool to room temperature, filter, wash the filter cake with chloroform, and dry to obtain the functionalized hollow glass microspheres. Among them, the mass ratio of the borate block nitrile rubber to the double bond modified hollow glass microspheres is 1:2.5, the catalyst is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst is 1.2% of the mass of the borate block nitrile rubber.

[0056] (6) Add nano-silica and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:5 into ethanol, disperse evenly and then heat to 82 °C, stir and reflux for 28 h, filter, wash the filter cake with ethanol, and dry to obtain double bond modified nano-silica; the mass of ethanol is 7.5 times the sum of the masses of the nano-silica and γ-(methacryloyloxy)propyltrimethoxysilane.

[0057] (7) The borate-block nitrile rubber was added to chloroform and fully dissolved to obtain a rubber solution with a mass fraction of 12%. Then, the catalyst and double-bond modified nano-silica were added to the rubber solution, ultrasonically dispersed evenly, heated to 55 °C, stirred and refluxed for 3.5 h, cooled to room temperature, filtered, and the filter cake was washed with chloroform and dried to obtain functionalized nano-silica. Among them, the mass ratio of the borate-block nitrile rubber to the double-bond modified nano-silica was 1:4, and the catalyst was (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst was 1.2% of the mass of the borate-block nitrile rubber.

[0058] The mass of the catalyst was 1.2% of the mass of the borate-block nitrile rubber.

[0059] (8) 110 parts by mass of styrene-butadiene rubber and 20 parts by mass of cis-butadiene rubber were added to a mixer, heated to 100 °C, kneaded for 12 min, then 14 parts by mass of functionalized hollow glass microspheres, 85 parts by mass of functionalized nano-silica and 6 parts by mass of carbon black N330 were added, and kneading was continued for 6 min. Then the temperature was lowered to 65 °C, 4 parts by mass of zinc oxide and 3 parts by mass of sulfur were added, and kneading was continued for 50 min to obtain the first rubber compound.

[0060] (9) 110 parts by mass of styrene-butadiene rubber and 20 parts by mass of cis-butadiene rubber were added to a mixer, heated to 100 °C, kneaded for 12 min, then 23 parts by mass of functionalized hollow glass microspheres, 70 parts by mass of functionalized nano-silica and 6 parts by mass of carbon black N330 were added, and kneading was continued for 6 min. Then the temperature was lowered to 65 °C, 4.5 parts by mass of zinc oxide and 3.5 parts by mass of sulfur were added, and kneading was continued for 50 min to obtain the second rubber compound.

[0061] (10) Heat the first rubber material to 103°C, then roll it through a rolling mill to form a first rubber strip with a thickness of 2 cm. Then wind the first rubber strip around the tire skeleton to form a first rubber winding layer. The first rubber winding layer and the tire skeleton together form a first rubber winding body. Heat the first rubber winding body to 112°C and keep it warm for 6 minutes to pre-vulcanize the first rubber winding layer. Heat the second rubber material to 103°C, then roll it through a rolling mill to form a second rubber strip with a thickness of 2 cm. Then wind the second rubber strip around the pre-vulcanized first rubber winding layer to form a second rubber winding layer. The second rubber winding layer, the pre-vulcanized first rubber winding layer, and the tire skeleton together form a second rubber winding body. Heat the second rubber winding body to 112°C and keep it warm for 13 minutes to pre-vulcanize the second rubber winding layer. Wind the first rubber strip around the pre-vulcanized second rubber winding layer to form a third rubber winding layer. The third rubber winding layer, the pre-vulcanized second rubber winding layer, and the pre-vulcanized first rubber winding layer together form a tire blank. The thickness ratio of the first rubber winding layer, the second rubber winding layer, and the third rubber winding layer is 0.6:1.8:1.5. Finally, put the tire blank into a solid tire mold and perform vulcanization treatment to obtain a multi-layer solid tire. The temperature of the vulcanization treatment is 150°C, the pressure is 7 MPa, and the time is 30 minutes.

[0062] Example 3

[0063] The processing method of the multi-layer solid tire in this example includes the following steps:

[0064] (1) Add n-octylboronic acid diethanolamine ester, trimellitic anhydride, and carbon tetrachloride to a reaction kettle, heat to 85°C, stir and reflux for 5 hours, and remove carbon tetrachloride by vacuum distillation to obtain a borate carboxylic acid compound. Among them, the molar ratio of n-octylboronic acid diethanolamine ester to trimellitic anhydride is 1:1, and the mass of carbon tetrachloride is 60% of the mass of n-octylboronic acid diethanolamine ester.

[0065] The structure of n-octylboronic acid diethanolamine ester is as follows:

[0066]

[0067] The structure of the borate carboxylic acid compound is as follows:

[0068]

[0069] (2) Add the borate carboxylic acid compound and thionyl chloride with a mass ratio of 1:6 to a reaction kettle, heat to reflux, stir and reflux for 8 hours to obtain a borate acyl chloride compound; the structure of the borate acyl chloride compound is as follows:

[0070]

[0071] (3) Add the terminal amino group nitrile rubber (acrylonitrile content is 18%, amino equivalent is 900) and chloroform into the reaction kettle, stir evenly to obtain a rubber solution with a mass fraction of 45%; then cool the materials in the reaction kettle to 0 °C, and under stirring conditions, dropwise add the chloroform solution (mass fraction is 60%) of the borate acyl chloride compound into the reaction kettle. After the dropping is completed, add triethylamine into the reaction kettle, then heat the materials in the reaction kettle to room temperature, continue stirring and reacting for 5 h, filter, and rotary evaporate the filtrate to obtain borate block nitrile rubber. Among them, the molar ratio of the amino group in the terminal amino group nitrile rubber to the acyl chloride group in the borate acyl chloride compound is 1:1.1, and the molar ratio of the borate acyl chloride compound to triethylamine is 1:2.4.

[0072] (4) Add hollow glass microspheres (average particle size is 40 μm) and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:3 into ethanol, disperse evenly and then heat to 85 °C, stir and reflux for 30 h, filter, wash the filter cake with ethanol, and dry to obtain double bond modified hollow glass microspheres; the mass of ethanol is 6 times the sum of the masses of the hollow glass microspheres and γ-(methacryloyloxy)propyltrimethoxysilane.

[0073] (5) Add the borate block nitrile rubber into chloroform, dissolve it fully to obtain a rubber solution with a mass fraction of 15%; then add the catalyst and the double bond modified hollow glass microspheres into the rubber solution, disperse evenly by ultrasonic wave, heat to 60 °C, stir and reflux for 2 h, cool to room temperature, filter, wash the filter cake with chloroform, and dry to obtain functionalized hollow glass microspheres. Among them, the mass ratio of the borate block nitrile rubber to the double bond modified hollow glass microspheres is 1:3, the catalyst is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst is 1.5% of the mass of the borate block nitrile rubber.

[0074] (6) Add nano-silica and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:6 into ethanol, disperse evenly and then heat to 85 °C, stir and reflux for 30 h, filter, wash the filter cake with ethanol, and dry to obtain double bond modified nano-silica; the mass of ethanol is 8 times the sum of the masses of the nano-silica and γ-(methacryloyloxy)propyltrimethoxysilane.

[0075] (7) The borate-block acrylonitrile-butadiene rubber was added to chloroform and fully dissolved to obtain a rubber solution with a mass fraction of 15%. Then, the catalyst and double-bond modified nano-silica were added to the rubber solution, ultrasonically dispersed evenly, heated to 60 °C, stirred and refluxed for 4 h, cooled to room temperature, filtered, the filter cake was washed with chloroform, and functionalized nano-silica was obtained after drying. Among them, the mass ratio of the borate-block acrylonitrile-butadiene rubber to the double-bond modified nano-silica was 1:5, the catalyst was (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst was 1.5% of the mass of the borate-block acrylonitrile-butadiene rubber.

[0076] (8) 115 parts by mass of styrene-butadiene rubber and 25 parts by mass of cis-butadiene rubber were added to a mixer, heated to 105 °C, and kneaded for 15 min. Then, 16 parts by mass of functionalized hollow glass microspheres, 90 parts by mass of functionalized nano-silica, and 7 parts by mass of carbon black N330 were added, and kneading was continued for 8 min. Then, the temperature was lowered to 70 °C, 4.5 parts by mass of zinc oxide and 3.5 parts by mass of sulfur were added, and kneading was continued for 60 min to obtain the first rubber compound.

[0077] (9) 115 parts by mass of styrene-butadiene rubber and 25 parts by mass of cis-butadiene rubber were added to a mixer, heated to 105 °C, and kneaded for 15 min. Then, 25 parts by mass of functionalized hollow glass microspheres, 75 parts by mass of functionalized nano-silica, and 7 parts by mass of carbon black N330 were added, and kneading was continued for 8 min. Then, the temperature was lowered to 70 °C, 5 parts by mass of zinc oxide and 4 parts by mass of sulfur were added, and kneading was continued for 60 min to obtain the second rubber compound.

[0078] (10) Heat the first rubber material to 105°C, then roll it through a rolling mill to form a first rubber strip with a thickness of 3 cm. Then wind the first rubber strip around the tire skeleton to form a first rubber winding layer. The first rubber winding layer and the tire skeleton form a first rubber winding body. Heat the first rubber winding body to 115°C and keep it warm for 8 min to pre-vulcanize the first rubber winding layer. Heat the second rubber material to 105°C, then roll it through a rolling mill to form a second rubber strip with a thickness of 3 cm. Then wind the second rubber strip around the pre-vulcanized first rubber winding layer to form a second rubber winding layer. The second rubber winding layer, the pre-vulcanized first rubber winding layer, and the tire skeleton form a second rubber winding body. Heat the second rubber winding body to 115°C and keep it warm for 14 min to pre-vulcanize the second rubber winding layer. Wind the first rubber strip around the pre-vulcanized second rubber winding layer to form a third rubber winding layer. The third rubber winding layer, the pre-vulcanized second rubber winding layer, and the pre-vulcanized first rubber winding layer form a tire blank. The thickness ratio of the first rubber winding layer, the second rubber winding layer, and the third rubber winding layer is 0.8:2:1.7. Finally, put the tire blank into a solid tire mold and perform vulcanization treatment to obtain a multi-layer solid tire. The temperature of the vulcanization treatment is 155°C, the pressure is 9 MPa, and the time is 40 min.

[0079] Example 4

[0080] The difference between the processing method of the multi-layer solid tire in this example and the processing method of the multi-layer solid tire in Example 1 is only that in step (1) of the processing method of the multi-layer solid tire in this example, dioctyl borate diethanolamine ester is replaced by cyclohexyl borate diethanolamine ester.

[0081] Example 5

[0082] The difference between the processing method of the multi-layer solid tire in this example and the processing method of the multi-layer solid tire in Example 1 is only that in step (1) of the processing method of the multi-layer solid tire in this example, dioctyl borate diethanolamine ester is replaced by 2-phenylethyl-1-borate diethanolamine ester.

[0083] Example 6

[0084] The difference between the processing method of the multi-layer solid tire in this example and the processing method of the multi-layer solid tire in Example 1 is only that in step (1) of the processing method of the multi-layer solid tire in this example, dioctyl borate diethanolamine ester is replaced by N-hexyl borate diethanolamine ester.

[0085] Comparative Example 1

[0086] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that in steps (8) and (9) of the processing method of the multi-layer solid tire in this comparative example, the functionalized hollow glass microspheres are replaced with the hollow glass microspheres in step (4) of the processing method of the multi-layer solid tire in Example 1.

[0087] Comparative Example 2

[0088] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that in steps (8) and (9) of the processing method of the multi-layer solid tire in this comparative example, the functionalized hollow glass microspheres are replaced with the double-bond modified hollow glass microspheres in step (4) of the processing method of the multi-layer solid tire in Example 1.

[0089] Comparative Example 3

[0090] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that in steps (8) and (9) of the processing method of the multi-layer solid tire in this comparative example, the functionalized nano-silica is replaced with the nano-silica in step (6) of the processing method of the multi-layer solid tire in Example 1.

[0091] Comparative Example 4

[0092] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that in steps (8) and (9) of the processing method of the multi-layer solid tire in this comparative example, the functionalized nano-silica is replaced with the double-bond modified nano-silica in step (6) of the processing method of the multi-layer solid tire in Example 1.

[0093] Comparative Example 5

[0094] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that the acrylonitrile content of the amino-terminated nitrile rubber in step (3) of the processing method of the multi-layer solid tire in this comparative example is 0.

[0095] Comparative Example 6

[0096] The difference between the processing method of the multi-layer solid tire in this comparative example and that in Example 1 lies only in that the acrylonitrile content of the amino-terminated nitrile rubber in step (3) of the processing method of the multi-layer solid tire in this comparative example is 26%.

[0097] Comparative Example 7

[0098] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that the amino equivalent of the terminal amino nitrile rubber in step (3) of the processing method of the multi-layer solid tire in this comparative example is 450.

[0099] Comparative Example 8

[0100] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that the amino equivalent of the terminal amino nitrile rubber in step (3) of the processing method of the multi-layer solid tire in this comparative example is 1850.

[0101] Comparative Example 9

[0102] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that in step (3) of the processing method of the multi-layer solid tire in this comparative example, the borate acyl chloride compound is replaced with isophthaloyl chloride.

[0103] Comparative Example 10

[0104] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that the average particle size of the hollow glass microspheres in step (4) of the processing method of the multi-layer solid tire in this comparative example is 10 μm.

[0105] Comparative Example 11

[0106] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that the average particle size of the hollow glass microspheres in step (4) of the processing method of the multi-layer solid tire in this comparative example is 60 μm.

[0107] Comparative Example 12

[0108] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that in step (10) of the processing method of the multi-layer solid tire in this comparative example, the first rubber material is replaced with the second rubber material.

[0109] Comparative Example 13

[0110] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that in step (10) of the processing method of the multi-layer solid tire in this comparative example, the second rubber material is replaced with the first rubber material.

[0111] Comparative Example 14

[0112] The difference between the processing method of the multi-layer solid tire in this comparative example and the processing method of the multi-layer solid tire in Example 1 is only that the first rubber material in step (10) of the processing method of the multi-layer solid tire in this comparative example is the second rubber material in step (9) of the processing method of the multi-layer solid tire in Example 1, and the second rubber material is the first rubber material in step (8) of the processing method of the multi-layer solid tire in Example 1.

[0113] Experimental Example 1

[0114] In order to investigate the comprehensive properties of the rubber materials in each example and comparative example, the first rubber materials in each example and comparative example were respectively subjected to vulcanization treatment (the vulcanization temperature was 145 °C, the pressure was 6 MPa, and the time was 30 min) to obtain the corresponding vulcanized rubbers. Then, the tensile strength, tear strength, 300% modulus at elongation, loss factor, abrasion loss, and cut amount of the vulcanized rubbers were tested. The results are shown in Table 1. Among them, the tensile strength and elongation at break were tested according to the method specified in the standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"; the tear strength was tested according to the method specified in the standard GBT 529-2008 "Determination method of tear strength of vulcanized rubber or thermoplastic rubber"; the loss factor was measured by a dynamic mechanical analyzer to measure the loss modulus and storage modulus of the solid tire at the experimental temperature, and the loss factor was obtained by calculating the ratio of the loss modulus to the storage modulus. The experimental temperature was 0 °C or 60 °C; the abrasion loss was tested according to the method specified in the standard GB / T 1689-1998 "Determination of abrasion resistance of vulcanized rubber (using Akron abrasion tester)"; the cut amount was obtained by using a steel knife tip to impact the rubber surface at a fixed frequency, and the mass loss of the rubber before and after the experiment was used as the experimental result of the cut amount. The test results in Table 1 are the average values of 5 test results.

[0115] Table 1 Comprehensive properties of the first rubber materials in each example and comparative example

[0116]

[0117] As can be seen from the test results in Table 1, the hollow glass microspheres modified with borate block nitrile rubber and nano-silica in the present invention are used as fillers for tire rubber, which can effectively improve the mechanical properties of rubber and tires. The nitrile rubber chain segments bonded to the surface of the fillers can be chemically bonded to the rubber molecular chains in the rubber matrix during vulcanization to form an integral body, improving the bonding strength between the fillers and the matrix, avoiding the agglomeration of the fillers, improving the dispersion uniformity of the fillers, and further effectively improving the mechanical properties of the rubber. In addition, the borate chain segments chemically bonded to the surface of the fillers have a cyclic structure with a large steric hindrance, which can further hinder the agglomeration between the fillers, ensure an appropriate spacing between the fillers, and the cyclic borate can form a coordination bond with nitrogen atoms, improving the bonding force between the fillers and between the fillers and the rubber matrix, and further improving the comprehensive properties of the rubber.

[0118] Experimental Example 2

[0119] In order to investigate the comprehensive properties of the multi-layer solid tires processed in each example and comparative example, solid tires for forklifts with the same size and model were processed according to the methods of each example and comparative example, and then the flexing temperature rise and service time of the solid tires were tested. The test method for the flexing temperature rise is as follows: a 30 kg load is applied to the solid tire, and the solid tire rotates at a speed of 1000 r / min under the action of a power loss testing machine, and the change in the surface temperature of the solid tire is recorded. The temperature rise value of the solid tire surface corresponding to 25 minutes of rotation time relative to the temperature before the experiment is used as the flexing temperature rise. The test method for the service time is as follows: the multi-layer solid tire is assembled onto the same charging forklift, then fully charged, and the maximum driving time of the forklift is tested under the same conditions, which is the service time.

[0120] Table 2 Flexing Temperature Rise and Service Time of Multi-layer Solid Tires Processed in Each Example and Comparative Example

[0121] Tire Flexing temperature rise (°C) Service time (h) Tire Flexing temperature rise (°C) Service time (h) Example 1 7.3 9.2 Comparative Example 5 23.5 4.6 Example 2 7.6 9.4 Comparative Example 6 23.1 4.8 Example 3 7.9 9.1 Comparative Example 7 22.5 5.0 Example 4 5.4 10.5 Comparative Example 8 23.6 4.7 Example 5 6.7 10.1 Comparative Example 9 22.5 4.5 Example 6 8.3 8.9 Comparative Example 10 21.7 4.9 Comparative Example 1 27.2 4.7 Comparative Example 11 22.4 5.1 Comparative Example 2 26.9 5.1 Comparative Example 12 20.8 5.2 Comparative Example 3 28.4 4.8 Comparative Example 13 20.6 5.5 Comparative Example 4 28.8 4.9 Comparative Example 14 20.1 4.8

[0122] As can be seen from the test results in Table 2, when the rubber material with a higher content of functionalized hollow glass microspheres is used as the central layer of the tire and the rubber material with a lower content of functionalized hollow glass microspheres is used as the base layer and outer layer of the tire in the present invention, the functionalized hollow glass microspheres can effectively reduce the dosage of white carbon black and reduce the weight of the tire center. The rubber molecular chains bonded to the surface of the hollow glass microspheres ensure that the hollow glass microsphere fillers have good elasticity and toughness, so that the middle part of the tire has both a smaller weight and good elasticity and buffering force, thereby reducing the frictional loss during vehicle driving and increasing the running time of the vehicle. During the vulcanization process of the tire blank, the rubber molecular chains on the surfaces of the hollow glass microspheres and nano-silica can be crosslinked and bonded together, improving the compactness and bonding density of the tire matrix, and further improving the heat conduction ability of the rubber tire and reducing the flexing temperature rise of the tire.

[0123] It should be noted that in this text, the terms "including", "comprising" and any other variants are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Specific examples are used in this text to elaborate on the principles and implementation manners of the technical solution of the present invention. The description of the above examples is only used to help understand the method of the present invention and its core idea. The above is only the preferred implementation manner of the present invention. It should be noted that due to the limited nature of literal expression and objectively infinite specific structures, for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the present invention to other occasions without improvement, shall all be regarded as the protection scope of the present invention.

Claims

1. A processing method of a multi-layer solid tire, characterized in that It includes the following steps: (1) React a borate acyl chloride compound with a terminal amino nitrile rubber to obtain a borate-block nitrile rubber; the acrylonitrile content of the terminal amino nitrile rubber is 10-18%, the amino equivalent is 900-1200, and the structure of the borate acyl chloride compound is as follows: Wherein, R is n-octyl, hexyl, cyclohexyl or 2-phenylethyl; (2) React the borate-block nitrile rubber with double-bond modified hollow glass microspheres to obtain functionalized hollow glass microspheres; the average particle size of the double-bond modified hollow glass microspheres is 25-40 μm; (3) React the borate-block nitrile rubber with double-bond modified nano-silica to obtain functionalized nano-silica; (4) Wind the first rubber strip around the tire carcass to form a first rubber winding layer, then wind the second rubber strip around the first rubber winding layer to form a second rubber winding layer, and then wind the first rubber strip around the second rubber winding layer to form a third rubber winding layer to obtain a tire blank. Finally, put the tire blank into a solid tire mold for vulcanization treatment to obtain a multi-layer solid tire; the first rubber strip is made by kneading and rolling the following components in parts by mass: 100-115 parts of styrene-butadiene rubber, 15-25 parts of cis-butadiene rubber, 12-16 parts of functionalized hollow glass microspheres, 80-90 parts of functionalized nano-silica, 5-7 parts of carbon black, 3-4.5 parts of zinc oxide, and 2.5-3.5 parts of sulfur; the second rubber strip is made by kneading and rolling the following components in parts by mass: 100-115 parts of styrene-butadiene rubber, 15-25 parts of cis-butadiene rubber, 20-25 parts of functionalized hollow glass microspheres, 65-75 parts of functionalized nano-silica, 5-7 parts of carbon black, 4-5 parts of zinc oxide, and 3-4 parts of sulfur.

2. The processing method of the multi-layer solid tire according to claim 1, characterized in that, The preparation method of the borate acyl chloride compound is as follows: React boric acid diethanolamine ester with trimellitic anhydride to obtain a borate carboxylic acid compound, and then react the borate carboxylic acid compound with thionyl chloride to obtain a borate acyl chloride compound; the boric acid diethanolamine ester is n-octyl boric acid diethanolamine ester, cyclohexyl boric acid diethanolamine ester, 2-phenylethyl-1-boric acid diethanolamine ester or N-hexyl boric acid diethanolamine ester; the reaction temperature of the boric acid diethanolamine ester and trimellitic anhydride is 75-85 °C, the time is 3-5 h, and the molar ratio of the boric acid diethanolamine ester to trimellitic anhydride is 1:1; the mass ratio of the borate carboxylic acid compound to thionyl chloride is 1:4-6.

3. The processing method of the multi-layer solid tire according to claim 1, characterized in that, The molar ratio of the amino group in the terminal amino nitrile rubber to the acyl chloride group in the borate acyl chloride compound is 1:1.05-1.

1.

4. The processing method of the multi-layer solid tire according to claim 1, characterized in that, The mass ratio of the borate-block nitrile rubber to the double-bond modified hollow glass microspheres is 1:2-3. The catalyst during the reaction is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxybenzylidene)ruthenium, and the mass of the catalyst is 1-1.5% of the mass of the borate-block nitrile rubber. The reaction temperature is 50-60 °C, and the time is 1-2 h.

5. The processing method of the multi-layer solid tire according to claim 1 or 4, characterized in that, The double-bond modified hollow glass microspheres are prepared by reacting hollow glass microspheres and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:2-3.

6. The processing method of the multi-layer solid tire according to claim 1, characterized in that The mass ratio of the borate-blocked nitrile rubber and the double-bond modified nano-silica is 1:3.5-5. The catalyst during the reaction is (1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloride(o-isopropoxybenzylidene)ruthenium. The mass of the catalyst is 1-1.5% of the mass of the borate-blocked nitrile rubber. The reaction temperature is 50-60 °C and the time is 3-4 h.

7. The processing method of the multi-layer solid tire according to claim 1 or 6, characterized in that The double-bond modified nano-silica is prepared by reacting nano-silica and γ-(methacryloyloxy)propyltrimethoxysilane with a mass ratio of 1:4-6.

8. The processing method of the multi-layer solid tire according to claim 1, characterized in that, The thickness of the first rubber strip and the second rubber strip is 1.5-3 cm. The processing method of the multi-layer solid tire further includes the following steps: heating the first rubber strip winding layer to 110-115 °C, keeping warm for 5-8 min for pre-vulcanization, then winding the second rubber strip on the pre-vulcanized first rubber winding layer to form a second rubber winding layer, and then heating the second rubber winding body to 110-115 °C, keeping warm for 10-14 min for pre-vulcanization, and then winding the first rubber strip on the pre-vulcanized second rubber winding layer to form a third rubber winding layer. The thickness ratio of the first rubber winding layer, the second rubber winding layer and the third rubber winding layer is 0.5-0.8:1.5-2:1.2-1.

7.

9. The processing method of the multi-layer solid tire according to claim 1, characterized in that The temperature of the vulcanization treatment is 145-155 °C, the pressure is 6-9 MPa, and the time is 25-40 min.

10. A multi-layer solid tire processed by the processing method of the multi-layer solid tire according to any one of claims 1-9.

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