Snow tire for new energy automobile and preparation method of snow tire

Abstract

The invention provides a snow tire for a new energy automobile and a preparation method of the snow tire, and belongs to the technical field of rubber composites.The snow tire comprises a tread, a buffer layer, a cord fabric layer and a tire bead, the tread rubber composition comprises 30-50 parts of modified natural rubber, 20-50 parts of solution polymerized styrene-butadiene rubber, 20-40 parts of flexible filler, 20-50 parts of carbon black, 10-20 parts of operating oil, 10-20 parts of a silane coupling agent, 1-3 parts of an anti-aging agent, 2-4 parts of an accelerant, 2-8 parts of an active agent and 2-4 parts of a vulcanizing agent. The preparation method of the modified natural rubber comprises the following steps: carrying out copolymerization on a hydroxyl myrcene monomer and 1, 4-polyisoprene to synthesize a polar copolymer with two sequence structures of end group aggregation or random arrangement, and introducing a fluorosilicone copolymer by utilizing hydroxylation grafting of a side chain to obtain the modified natural rubber. The low-temperature resistance and the wet skid resistance of the tire can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber composite materials, and in particular to a snow tire for a new energy vehicle and a preparation method thereof. Background Art

[0002] In areas with low temperatures and snowy weather all year round, the use of winter tires is gaining more and more attention from car users. Winter tires are mainly used in low temperatures and on snowy roads, which requires the hardness of the tire tread rubber to be lower than that of ordinary tires at low temperatures, and to have excellent grip on ice and snow to improve the tire's maneuverability and ensure driving safety.

[0003] In the prior art, butadiene rubber is usually added to natural rubber. The glass transition temperature Tg of butadiene rubber is -100°C, which is the best synthetic rubber for cold resistance. It can reduce the hardening degree of tread rubber at low temperatures and increase the contact area between the tire tread and the ground. However, butadiene rubber has poor anti-skid ability. Although adding solution-polymerized styrene-butadiene rubber can improve anti-skid ability to a certain extent, it increases the rolling resistance and heat generation of the tire. Summary of the invention

[0004] In order to solve the above problems, a snow tire for new energy vehicles and a preparation method thereof are provided. The tread rubber of the tire uses modified natural rubber and solution polymerized styrene butadiene rubber as the base material. The modified natural rubber is grafted with fluorosilicone copolymer on the side chain to improve the cold resistance of the natural rubber. By matching with solution polymerized styrene butadiene rubber, the low temperature resistance and wet skid resistance of the rubber can be balanced; the tread rubber contains flexible fillers, which, in combination with other components, can destroy the regularity of the molecular chain and reduce the interaction between polymer chains, thereby increasing the plasticity of the polymer, while ensuring the compatibility between polymers, so that the tire has low heat generation and low rolling resistance.

[0005] In one aspect, the present invention provides a snow tire for a new energy vehicle, comprising a tread, a buffer layer, a cord layer and a bead, wherein the tread is made by mixing and vulcanizing a tread rubber composition, and the tread rubber composition comprises, by weight:

[0006] 30-50 parts of modified natural rubber, 20-50 parts of solution polymerized styrene-butadiene rubber, 20-40 parts of flexible filler, 20-50 parts of carbon black, 10-20 parts of operating oil, 10-20 parts of silane coupling agent, 1-3 parts of antioxidant, 2-4 parts of accelerator, 2-8 parts of activator and 2-4 parts of vulcanizer.

[0007] The preparation method of the modified natural rubber comprises the following steps: copolymerizing hydroxymyrcene monomer and 4-polyisoprene to synthesize a polar copolymer, and then introducing a fluorosilicone copolymer by grafting the hydroxylation of the side chain to obtain the modified natural rubber.

[0008] Optionally, the mass ratio of the modified natural rubber, the solution polymerized styrene-butadiene rubber and the flexible filler is 1:1:0.5-0.8.

[0009] Snow tires need to have low temperature resistance and wet-slip resistance. The present invention provides a snow tire for new energy vehicles, which uses modified natural rubber and solution-polymerized styrene-butadiene rubber as base materials, can balance the low temperature resistance and wet-slip resistance of the rubber material, and the added flexible filler, in combination with other components, can destroy the regularity of the molecular chain, reduce the interaction between polymer chains, thereby increasing the plasticity of the polymer, and at the same time ensure the compatibility between polymers, so that the tire has low heat generation and low rolling resistance, meeting the performance requirements of new energy vehicles.

[0010] The invention copolymerizes hydroxymyrcene monomer and 1,4-polyisoprene to synthesize polar copolymers with two sequence structures of terminal group aggregation or random arrangement, and then introduces fluorosilicone copolymer by hydroxylation grafting of side chains to obtain a random molecular chain structure. The introduction of fluorosilicone copolymer can ensure mechanical properties, while destroying the regularity of molecular chains, reducing the interaction force between polymer chains and reducing the glass transition temperature Tg, so that the rubber material has good low temperature resistance.

[0011] Optionally, the content of cis-1,4-polyisoprene in 1,4-polyisoprene is more than 60%. Optionally, the content of cis-1,4-polyisoprene in 1,4-polyisoprene is 60%-80%. The present invention adopts 1,4-polyisoprene with cis structure. To a certain extent, the cis structure has a larger steric hindrance, which can weaken the interaction between rubber molecular chains, increase the movement space of rubber molecular chain segments, make rubber molecules more compliant, effectively reduce the Tg point of rubber materials, and make the final snow tires can maintain better softness and higher grip at low temperatures.

[0012] Optionally, the preparation method of the polar copolymer comprises the following steps: reacting a hydroxymyrcene monomer and a 1,4-polyisoprene monomer at 40-50° C. to obtain a polar copolymer;

[0013] The polar copolymer and the fluorosilicon copolymer are reacted at 80-90° C. under the action of tin laurate as a catalyst, and then washed and dried in sequence to obtain the modified natural rubber.

[0014] Optionally, the structural formula of the fluorine-silicon copolymer is as follows:

[0015]

[0016] Among them, R f It is trifluoropropyl, R is one or both of ethyl and methyl; X / (X+3m+3n)=0.1%-50%, n / (m+n)=0.5-1.

[0017] The fluorosilicone copolymer in the present invention is a highly trans structure. Due to the low chain regularity of the trans fluorosilicone copolymer, the glass transition temperature is 5-10°C lower than that of the ordinary fluorosilicone copolymer, which improves the application of the rubber at low temperatures to a certain extent; the introduction of dimethyl segments and diethyl segments will reduce the glass transition temperature of the copolymer, further improving the low temperature resistance of the rubber. In addition, the alkyl groups distributed in the fluorosilicone copolymer bring reinforcement and low temperature resistance while improving the compatibility with solution-polymerized styrene-butadiene rubber, and the introduction of trifluoropropyl groups can ensure the mechanical properties of the tire.

[0018] Optionally, the preparation method of the fluorosilicone copolymer comprises the following steps: removing water from the mixed ring body containing trans- and cis-methyltrifluoropropylcyclotrisiloxane and cyclotrisiloxane, adding tetramethylammonium hydroxide and tetrahydrofuran to carry out polymerization reaction at 60-180° C., and finally adding formic acid to remove unreacted small molecules and by-products to obtain a high trans-fluorosilicone copolymer.

[0019] Optionally, the cyclotrisiloxane is one or more of hexaphenylcyclotrisiloxane, hexaethylcyclotrisiloxane, and hexamethylcyclotrisiloxane.

[0020] Optionally, the content of trans-methyltrifluoropropylcyclotrisiloxane accounts for more than 40% of the mass of the mixed ring body. The mass ratio of the cyclotrisiloxane to the mixed ring body is 10-20:100.

[0021] Optionally, the method for preparing the flexible filler comprises the following steps:

[0022] The tartaric acid containing hydroxyl groups and glycerol with fatty side chains are mixed, tetrabutyl titanate as a catalyst is added, reacted at a temperature of 140-160°C, and washed and dried in sequence to obtain a flexible filler;

[0023] Wherein, the molar ratio of tartaric acid to glycerol is 3:(1-2).

[0024] In the present invention, tartaric acid containing a hydroxyl group and glycerol with a fatty side chain are used to prepare polytartaric acid triol ester, which is introduced into a rubber material in a melt copolymerization manner as a flexible chain segment. When the tartaric acid and the glycerol with a side chain are introduced, the molecular chain of the rubber becomes flexible, and the growth of the glycerol chain segment and the introduction of the side chain give the rubber material better flexibility, which can improve the compatibility with rubber, improve the coordination and dispersion effect with carbon black, and improve the dispersibility of carbon black, thereby reducing the heat generation of the rubber material and reducing the rolling resistance.

[0025] Optionally, the solution polymerized styrene butadiene rubber has a vinyl content of 30%-40% and a styrene content of 10%-20%.

[0026] Optionally, the carbon black is fumed silica, and the specific surface area of ​​fumed silica is 180m 3 / g-250m 3 / g;

[0027] and / or the silane coupling agent is γ-aminopropyltriethoxysilane (abbreviated as KH550), γ-(2,3-epoxypropoxy)propyltrimethoxysilane (abbreviated as KH560), γ-(methacryloyloxy)propyltrimethoxysilane (abbreviated as KH570), γ-mercaptopropyltriethoxysilane (abbreviated as KH580), γ-mercaptopropyltrimethoxysilane (abbreviated as KH590), γ-aminoethylaminopropyltrimethoxysilane (abbreviated as KH900), N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (abbreviated as KH602), bis-(γ-triethoxysilylpropyl) tetrasulfide (abbreviated as Si69), bis-(γ-triethoxysilylpropyl) disulfide (abbreviated as Si75), vinyltriethoxysilane, vinyltrimethoxysilane, ethyltriacetoxysilane, methyltrimethoxysilane, methyltriethylketoximesilane, vinyltriethylketoximesilane or any combination thereof.

[0028] Optionally, the process oil is one or more of treated aromatic oil (TDAE) or residual aromatic extract (RAE) or medium soluble extract (MES).

[0029] Optionally, the antioxidant is at least one of physical protective wax, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (abbreviated as antioxidant 6PPD) and 2,2,4-trimethyl-1,2-dihydroquinoline polymer (abbreviated as antioxidant RD).

[0030] Optionally, the accelerator is N-tert-butyl-2-benzothiazole sulfenamide.

[0031] Optionally, the active agent is zinc oxide or stearic acid.

[0032] Optionally, the vulcanizing agent is at least one of dibenzoyl peroxide, tetramethylthiuram disulfide, barium peroxide, cadmium peroxide, magnesium peroxide, zinc peroxide, bis(2,4-dichloroformyl) peroxide, di-tert-butyl peroxide, 1,4-di-tert-butylperoxyisopropylbenzene, diisopropyl peroxide, tert-butyl perbenzoate, tert-butyl isopropyl peroxide, isochloropropyl peroxide, tert-butyl isopropyl carbonate, and tert-butyl peroxycarbonate.

[0033] A second aspect of the present invention provides a method for preparing a snow tire for a new energy vehicle, the method comprising the following steps:

[0034] (1) mixing modified natural rubber, solution polymerized styrene-butadiene rubber and flexible filler in one step, then adding carbon black, process oil, silane coupling agent, antioxidant and activator for two-step mixing and then discharging to obtain a mixed rubber;

[0035] (2) mixing the rubber compound, the accelerator and the vulcanizing agent in three steps, and obtaining a tread rubber composition after the rubber compound is discharged and cooled;

[0036] (3) The cord layer, the buffer layer and the tire bead are combined and formed, and the tread rubber composition is attached to the buffer layer to form a tire blank, and then the tire blank is vulcanized to obtain a snow tire for new energy vehicles.

[0037] Optionally, the temperature of the one-step mixing is 40-50° C. and the time is 5-10 min;

[0038] The temperature of the two-step mixing is 120-130°C and the time is 5-10 minutes;

[0039] The temperature of the three-step mixing is 70-80° C. and the time is 2-3 minutes.

[0040] Compared with the prior art, the present invention achieves at least one of the following beneficial effects:

[0041] (1) The present invention provides a snow tire for new energy vehicles, wherein the tread rubber of the tire is based on modified natural rubber and solution polymerized styrene butadiene rubber, and the modified natural rubber is grafted with fluorosilicone copolymer on the side chain to improve the cold resistance of the natural rubber. By cooperating with the solution polymerized styrene butadiene rubber, the low temperature resistance and wet skid resistance of the rubber can be balanced; the tread rubber contains a flexible filler, which, in combination with other components, can destroy the regularity of the molecular chain and reduce the interaction between polymer chains, thereby increasing the plasticity of the polymer, while ensuring the compatibility between polymers, so that the tire has low heat generation and low rolling resistance.

[0042] (2) The fluorosilicone copolymer in the present invention has a high trans structure. Due to the low chain regularity of the trans fluorosilicone copolymer, the glass transition temperature is 5-10°C lower than that of the ordinary fluorosilicone copolymer, which improves the application of the rubber at low temperatures to a certain extent; the introduction of dimethyl segments and diethyl segments will reduce the glass transition temperature of the copolymer, further improving the low temperature resistance of the rubber. In addition, the alkyl groups distributed in the fluorosilicone copolymer bring reinforcement and low temperature resistance while improving the compatibility with solution-polymerized styrene-butadiene rubber. The introduction of trifluoropropyl groups can ensure the mechanical properties of the tire.

[0043] (3) The present invention In the present invention, tartaric acid containing a hydroxyl group and propylene glycol with a fatty side chain are used to prepare polytartrate triol ester, which is introduced into the rubber compound by melt copolymerization as a flexible chain segment. When tartaric acid and propylene glycol with a side chain are introduced, the molecular chain of the rubber becomes flexible, and the growth of the propylene glycol chain segment and the introduction of the side chain give the rubber compound better flexibility, which can improve the compatibility with rubber, improve the coordination and dispersion effect with carbon black, and improve the dispersibility of carbon black, thereby reducing the heat generation of the rubber compound and reducing the rolling resistance. DETAILED DESCRIPTION

[0044] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below by way of examples.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0046] Example 1

[0047] In this embodiment, the snow tire for new energy vehicles includes a tread, a buffer layer, a cord layer and a bead. The tread is made by mixing and vulcanizing a tread rubber composition. The tread rubber composition includes, by weight:

[0048] 30 parts of modified natural rubber; 20 parts of solution polymerized styrene-butadiene rubber, in which the vinyl content is 30% and the styrene content is 10%; 20 parts of flexible filler; 20 parts of fumed silica, with a specific surface area of ​​180m 3 / g; 10 parts of operating oil RAE; 15 parts of silane coupling agent γ-aminopropyltriethoxysilane; 2 parts of antioxidant 6PPD; 2 parts of accelerator N-tert-butyl-2-benzothiazolesulfonamide; 3 parts of zinc oxide and 2 parts of dibenzoyl peroxide.

[0049] The preparation method of modified natural rubber comprises: (1) reacting hydroxymyrcene monomer and 1,4-polyisoprene monomer containing 60% cis-1,4-polyisoprene at 40° C. to obtain a polar copolymer;

[0050] (2) 16 g of hexamethylcyclotrisiloxane and 300 g of a mixed ring body containing 70% trans-methyltrifluoropropylcyclotrisiloxane were added to a reactor, and the water was removed under vacuum for 1.5 h; after nitrogen replacement, 0.25 g of initiator potassium hydroxide and 0.15 g of tetramethylammonium hydroxide were added, and the temperature was raised to 130° C. for reaction for 2 h; the reaction process was carried out under dry N2 flow and mechanical stirring; after the reaction was completed, 0.6 g of formic acid was added to the reaction product on an open mill to neutralize the initiator, and after thinning for several times, unreacted small molecules and by-products were removed under reduced pressure at 170° C. to obtain a high trans-fluorosilicone copolymer with an actual molecular weight of 930,000, an actual dimethylsiloxane chain content of 9.1%, and a trans-methyltrifluoropropylsiloxane chain content of 63%.

[0051] (3) The polar copolymer and the high trans-fluorosilicon copolymer are reacted at a mass ratio of 1:1 at 80° C. in the presence of a catalyst, tin laurate, and then washed and dried in sequence to obtain a modified natural rubber.

[0052] The preparation method of the flexible filler comprises the following steps: mixing tartaric acid containing a hydroxyl group and 2-methyl-1,2,3-propanetriol having a fatty side chain in a molar ratio of 3:1, adding tetra-n-butyl titanate as a catalyst, reacting at a temperature of 140°C, and washing and drying in sequence to obtain the flexible filler.

[0053] The manufacturing process of the above tire comprises the following steps:

[0054] (1) The modified natural rubber, solution polymerized styrene-butadiene rubber and flexible filler are mixed in one step at 40°C for 5 minutes, and then fumed silica, process oil, silane coupling agent, antioxidant and activator are added and mixed in two steps at 120°C for 5 minutes, and then the rubber is discharged to obtain a mixed rubber.

[0055] (2) The rubber compound, the accelerator and the vulcanizer are mixed in three steps at 70° C. for 3 min, and the rubber compound is discharged and cooled to obtain a tread rubber composition.

[0056] (3) The cord layer, the buffer layer and the tire bead are combined and formed, and the tread rubber composition is attached to the buffer layer to form a tire blank, and then the tire blank is vulcanized to obtain a snow tire for new energy vehicles.

[0057] Example 2

[0058] In this embodiment, the snow tire for new energy vehicles includes a tread, a buffer layer, a cord layer and a bead. The tread is made by mixing and vulcanizing a tread rubber composition. The tread rubber composition includes, by weight:

[0059] 50 parts of modified natural rubber; 50 parts of solution polymerized styrene-butadiene rubber, in which the vinyl content is 30% and the styrene content is 10%; 40 parts of flexible filler; 40 parts of fumed silica, with a specific surface area of ​​250m 3 / g; operating oil MES 20 parts; silane coupling agent KH580 20 parts; antioxidant RD 2 parts; accelerator N-tert-butyl-2-benzothiazole sulfenamide 2 parts; stearic acid 3 parts and di-tert-butyl peroxide 2 parts.

[0060] The preparation method of modified natural rubber comprises: (1) reacting hydroxymyrcene monomer and 1,4-polyisoprene monomer containing 80% cis-1,4-polyisoprene at 50° C. to obtain a polar copolymer;

[0061] (2) 25 g of hexaethylcyclotrisiloxane and 300 g of a mixed ring body containing 70% trans-methyltrifluoropropylcyclotrisiloxane were added to a reactor, and the water was removed under vacuum for 1.5 h; after nitrogen replacement, 0.25 g of initiator potassium hydroxide and 0.15 g of tetramethylammonium hydroxide were added, and the temperature was raised to 130° C. for reaction for 2 h; the reaction process was carried out under dry N2 flow and mechanical stirring; after the reaction was completed, 0.6 g of formic acid was added to the reaction product on an open mill to neutralize the initiator, and after thinning it several times, unreacted small molecules and by-products were removed under reduced pressure at 170° C. to obtain a high trans-fluorosilicone copolymer with an actual molecular weight of 910,000, a diethylsilyl chain siloxane content of 8.0%, and a trans-methyltrifluoropropylsiloxane chain content of 63%.

[0062] (3) The polar copolymer and the high trans-fluorosilicone copolymer are reacted at a mass ratio of 1:1 at 90° C. in the presence of a catalyst, tin laurate, and then washed and dried in sequence to obtain a modified natural rubber.

[0063] The preparation method of the flexible filler comprises the following steps: mixing tartaric acid containing a hydroxyl group and 2-methyl-1,2,3-propanetriol having a fatty side chain in a molar ratio of 3:2, adding tetrabutyl titanate as a catalyst, reacting at a temperature of 140°C, and washing and drying in sequence to obtain the flexible filler.

[0064] The manufacturing process of the above tire comprises the following steps:

[0065] (1) The modified natural rubber, solution polymerized styrene-butadiene rubber and flexible filler were mixed in one step at 50°C for 5 minutes, and then fumed silica, process oil, silane coupling agent, antioxidant and activator were added and mixed in two steps at 130°C for 5 minutes, and then the rubber was discharged to obtain a mixed rubber.

[0066] (2) The rubber compound, the accelerator and the vulcanizer are mixed in three steps at a temperature of 80° C. for 3 min, and the rubber compound is discharged and cooled to obtain a tread rubber composition.

[0067] (3) The cord layer, the buffer layer and the tire bead are combined and formed, and the tread rubber composition is attached to the buffer layer to form a tire blank, and then the tire blank is vulcanized to obtain a snow tire for new energy vehicles.

[0068] Example 3

[0069] In this embodiment, the snow tire for new energy vehicles includes a tread, a buffer layer, a cord layer and a bead. The tread is made by mixing and vulcanizing a tread rubber composition. The tread rubber composition includes, by weight:

[0070] 40 parts of modified natural rubber; 40 parts of solution polymerized styrene-butadiene rubber, in which the vinyl content is 40% and the styrene content is 10%; 20 parts of flexible filler; 40 parts of fumed silica, with a specific surface area of ​​200m 3 / g; 15 parts of operating oil TDAE; 20 parts of silane coupling agent KH900; 2 parts of antioxidant RD; 3 parts of accelerator N-tert-butyl-2-benzothiazole sulfenamide; 3 parts of zinc oxide and 2 parts of diisopropylbenzene peroxide.

[0071] The preparation method of modified natural rubber comprises: (1) reacting hydroxymyrcene monomer and 1,4-polyisoprene monomer containing 70% cis-1,4-polyisoprene at 45° C. to obtain a polar copolymer;

[0072] (2) 25 g of hexaethylcyclotrisiloxane and 300 g of a mixed ring body containing 70% trans-methyltrifluoropropylcyclotrisiloxane were added to a reactor, and the water was removed under vacuum for 1.5 h; after nitrogen replacement, 0.25 g of initiator potassium hydroxide and 0.15 g of tetramethylammonium hydroxide were added, and the temperature was raised to 130° C. for reaction for 2 h; the reaction process was carried out under dry N2 flow and mechanical stirring; after the reaction was completed, 0.6 g of formic acid was added to the reaction product on an open mill to neutralize the initiator, and after thinning it several times, unreacted small molecules and by-products were removed under reduced pressure at 170° C. to obtain a high trans-fluorosilicone copolymer with an actual molecular weight of 910,000, a diethylsilyl chain siloxane content of 8.0%, and a trans-methyltrifluoropropylsiloxane chain content of 63%.

[0073] (3) The polar copolymer and the high trans-fluorosilicone copolymer are reacted at a mass ratio of 1:1 at 85° C. in the presence of a catalyst, tin laurate, and then washed and dried in sequence to obtain a modified natural rubber.

[0074] The preparation method of the flexible filler comprises the following steps: mixing tartaric acid containing a hydroxyl group and 2-methyl-1,2,3-propanetriol having a fatty side chain in a molar ratio of 3:1, adding tetra-n-butyl titanate as a catalyst, reacting at a temperature of 150°C, and washing and drying in sequence to obtain the flexible filler.

[0075] The manufacturing process of the above tire comprises the following steps:

[0076] (1) The modified natural rubber, solution polymerized styrene-butadiene rubber and flexible filler were mixed in one step at 45°C for 8 minutes, and then fumed silica, process oil, silane coupling agent, antioxidant and activator were added and mixed in two steps at 125°C for 6 minutes, and then the rubber was discharged to obtain a mixed rubber.

[0077] (2) The rubber compound, the accelerator and the vulcanizer are mixed in three steps at a temperature of 75° C. for 3 min, and the rubber compound is discharged and cooled to obtain a tread rubber composition.

[0078] (3) The cord layer, the buffer layer and the tire bead are combined and formed, and the tread rubber composition is attached to the buffer layer to form a tire blank, and then the tire blank is vulcanized to obtain a snow tire for new energy vehicles.

[0079] Example 4

[0080] Based on Example 3, the main difference is that the flexible filler is di(2-ethylhexyl) phthalate. Other steps are the same as those in Example 3.

[0081] Example 5

[0082] Based on Example 3, the main difference is that the vinyl content of the solution-polymerized styrene-butadiene rubber is 10%, and the styrene content is 30%. Other steps are the same as in Example 3.

[0083] Example 6

[0084] Based on Example 3, the main difference is that the content of cis-1,4-polyisoprene in 1,4-polyisoprene in the preparation process of modified natural rubber is 40%. Other steps are the same as Example 3.

[0085] Comparative Example 1

[0086] Based on Example 1, the main difference is that the natural rubber is not modified, and the other steps are the same as Example 1.

[0087] Comparative Example 2

[0088] Based on Example 1, the main difference is that 80 parts of natural rubber are modified, and the other steps are the same as Example 1.

[0089] Comparative Example 3

[0090] Based on Example 1, the main difference is that 60 parts of flexible filler are used, and the other steps are the same as Example 1.

[0091] The tread rubber compositions obtained in the examples and comparative examples were vulcanized separately to obtain tread samples, and the performance of the tread samples was tested. The specific test results are shown in Table 1.

[0092] Table 1

[0093]

[0094] As shown in Table 1, the snow tire for new energy vehicles prepared by the present invention has a hardness of 45-55°C at room temperature, a small change in hardness at -20°C, and an elastic modulus E' at -25°C of not more than 15, which proves that the tire has good grip on ice and snow; Tg is in the range of -65--55°C, and tanδ0°C is in the range of 0.60-0.75, which has good resistance to low temperature and wet skid resistance, and can make the snow tire have a shorter low-temperature braking distance, which is more conducive to improving winter driving safety. At the same time, Tanδ60°C is not higher than 0.2, ensuring that the tire has low rolling resistance.

[0095] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A snow tire for new energy vehicles, comprising a tread, a buffer layer, a cord layer and a bead, characterized in that: The tread is prepared by mixing and vulcanizing a tread rubber composition, which comprises, by weight: 30-50 parts of modified natural rubber, 20-50 parts of solution-polymerized styrene-butadiene rubber, 20-40 parts of flexible filler, 20-50 parts of carbon black, 10-20 parts of process oil, 10-20 parts of silane coupling agent, 1-3 parts of antioxidant, 2-4 parts of accelerator, 2-8 parts of active agent and 2-4 parts of vulcanizing agent; The preparation method of the modified natural rubber comprises the following steps: copolymerizing hydroxymyrcene monomer and 1,4-polyisoprene to synthesize a polar copolymer, and then introducing a fluorosilicone copolymer by grafting the hydroxylation of the side chain to obtain the modified natural rubber.

2. The snow tire for new energy vehicles according to claim 1, characterized in that: The content of cis-1,4-polyisoprene in 1,4-polyisoprene accounts for more than 60%.

3. The snow tire for new energy vehicles according to claim 2, characterized in that: The content of cis-1,4-polyisoprene in 1,4-polyisoprene is 60%-80%.

4. The snow tire for new energy vehicles according to claim 1, characterized in that: The preparation method of the polar copolymer comprises the following steps: reacting a hydroxymyrcene monomer and a 1,4-polyisoprene monomer at 40-50° C. to obtain a polar copolymer; The polar copolymer and the fluorosilicon copolymer are reacted at 80-90° C. under the action of tin laurate as a catalyst, and then washed and dried in sequence to obtain the modified natural rubber.

5. The snow tire for new energy vehicles according to claim 1, characterized in that: The structural formula of fluorosilicone copolymer is as follows: Among them, R f It is trifluoropropyl, R is one or both of ethyl and methyl; X / (X+3m+3n)=0.1%-50%, m / (m+n)=0.5-1.

6. The snow tire for new energy vehicles according to claim 1, characterized in that: The preparation method of the flexible filler comprises the following steps: The tartaric acid containing hydroxyl groups and glycerol with fatty side chains are mixed, tetrabutyl titanate as a catalyst is added, reacted at a temperature of 140-160°C, and washed and dried in sequence to obtain a flexible filler; Wherein, the molar ratio of tartaric acid to glycerol is 3:(1-2).

7. The snow tire for new energy vehicles according to claim 1, characterized in that: The vinyl content of solution-polymerized styrene-butadiene rubber is 30%-40%, and the styrene content is 10%-20%.

8. The snow tire for new energy vehicles according to claim 1, characterized in that: The carbon black is fumed silica, and the specific surface area of ​​fumed silica is 180m 3 / g-250m 3 / g; And / or the silane coupling agent is γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, bis-(γ-triethoxysilylpropyl)tetrasulfide, bis-(γ-triethoxysilylpropyl)disulfide, vinyltriethoxysilane, vinyltrimethoxysilane, ethyltriacetoxysilane, methyltrimethoxysilane, methyltriethylketoximesilane, vinyltriethylketoximesilane or any combination thereof.

9. A method for preparing a snow tire for a new energy vehicle according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) mixing modified natural rubber, solution polymerized styrene-butadiene rubber and flexible filler in one step, then adding carbon black, process oil, silane coupling agent, antioxidant and activator for two-step mixing and then discharging to obtain a mixed rubber; (2) mixing the rubber compound, the accelerator and the vulcanizing agent in three steps, and obtaining a tread rubber composition after the rubber compound is discharged and cooled; (3) The cord layer, the buffer layer and the tire bead are combined and formed, and the tread rubber composition is attached to the buffer layer to form a tire blank, and then the tire blank is vulcanized to obtain a snow tire for new energy vehicles.

10. The preparation method according to claim 9, characterized in that: The temperature of the one-step mixing is 40-50°C and the time is 5-10min; The temperature of the two-step mixing is 120-130°C and the time is 5-10 minutes; The temperature of the three-step mixing is 70-80° C. and the time is 2-3 minutes.

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