A hydrazide compound, a rubber composition, and a method for preparing and using the same

Abstract

The present application relates to the technical field of rubber, in particular to a kind of hydrazide compound, rubber composition and its preparation method and application.The present application provides a kind of hydrazide compound, is mono-hydrazide compound or double hydrazide compound, they have lower melting point, can be well dispersed in rubber matrix in the range of mixing temperature, further ensure its effect.And the hydrazide compound of this kind is added to rubber composition, can obtain the tire product of processing performance improvement, dynamic modulus promotion, anti-wet sliding and balanced rolling resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rubber technology, in particular to a hydrazide compound, a rubber composition and a preparation method and application thereof. BACKGROUND

[0002] Since Michelin Company proposed the concept of "green tire" in 1992, the research and production of low rolling resistance and low heat generation tire has become a very important issue for major tire companies and research institutions. Studies have shown that about 20% of the fuel consumption of a car is used to overcome the rolling resistance of the tire, so from the perspective of improving energy utilization and achieving social sustainable development, the research and development of low rolling resistance and low heat generation tire is crucial.

[0003] Adding a hydrazide compound to the tire formula is an effective way to reduce its rolling resistance and heat generation, and more commonly used is isophthalic dihydrazide. However, there are still some areas that need to be improved. On the one hand, the addition of isophthalic dihydrazide increases the Mooney viscosity of the rubber compound and shortens the scorch time, that is, it affects the processing performance and processing safety of the rubber compound. On the other hand, the effect of isophthalic dihydrazide in reducing rolling resistance and heat generation is unstable, which may be related to its high melting point (232℃), affecting its dispersion in the rubber matrix. SUMMARY

[0004] In order to solve the above technical problems, the purpose of the present application is to provide a new type of hydrazide compound and a preparation method thereof, which has a lower melting point and can achieve good dispersion in the rubber matrix within the mixing temperature range, thereby ensuring its effect. And adding this type of hydrazide compound to the rubber composition can obtain a tire product with improved processing performance, improved dynamic modulus, improved wet skid resistance, and balanced rolling resistance.

[0005] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0006] A hydrazide compound, having a general formula shown in a mono-hydrazide compound of formula (a) or a di-hydrazide compound of formula (b):

[0007] Mono-hydrazide compound:

[0008] Di-hydrazide compound:

[0009] R1 is a straight chain or branched, saturated or unsaturated, alkyl or aromatic group having 0-50 carbon atoms; preferably, R1 is an alkyl or aromatic group having 1-40 carbon atoms, more preferably, R1 is an alkyl or aromatic group having 3-35 carbon atoms, and still more preferably, R1 is an alkyl or aromatic group having 5-25 carbon atoms; R2 is a straight chain or branched, saturated or unsaturated, alkyl or aromatic group having 0-50 carbon atoms; preferably, R2 is an alkyl or aromatic group having 1-40 carbon atoms, more preferably, R2 is an alkyl or aromatic group having 3-30 carbon atoms, and still more preferably, R2 is an alkyl or aromatic group having 5-25 carbon atoms. R1 and R2 can be the same or different.

[0010] In addition, the hydrazide compound has a melting point in the range of 15-180°C, so that good dispersion of the hydrazide compound in the rubber matrix can be achieved, thereby ensuring the stability of the effect thereof.

[0011] According to the above description, some representative examples of the hydrazide compound (of the present application but not limited to) are as follows:

[0012] Lauryl hydrazide

[0013]

[0014] Stearic hydrazide

[0015]

[0016] Oleic hydrazide

[0017]

[0018] Adipic hydrazide

[0019]

[0020] It should be noted that the hydrazide compound represented by formula (a) or formula (b) includes all the structures above, but is not limited to the structures above, and all the structures conforming to formula (a) or formula (b) are within the protection scope of the present application.

[0021] Further, the present application also provides a preparation method of the hydrazide compound, which is synthesized according to the following steps:

[0022] S1: adding an organic solvent, an appropriate amount of phenylhydrazine, and an appropriate amount of triethylamine into a reaction container, and starting stirring; and reducing the temperature of the system to below 4°C;

[0023]

[0024] S2: adding an appropriate amount of acyl chloride dropwise into the reaction container, and controlling the dropwise rate to maintain the system at the reaction temperature;

[0025] S3: after the dropwise addition is completed, continuously stirring until the reaction is completed;

[0026] ​S4: The reaction solution is filtered, and the filter residue is washed with an organic solvent;

[0027] S5: After the filtrate is collected and the organic solvent is removed, the hydrazide compound is obtained.

[0028] Preferably, the acyl chloride of S2 includes one or more of propionyl chloride, butyryl chloride, valeryl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride, nonanoyl chloride, decanoyl chloride, undecanoyl chloride, lauryl chloride, tridecanoyl chloride, myristoyl chloride, pentadecanoyl chloride, palmitoyl chloride, heptadecanoyl chloride, stearoyl chloride, nonadecanoyl chloride, arachidoyl chloride, heneicosanoyl chloride, behenoyl chloride, dodecyl-9-enoyl chloride, 12-tridecenoic acid chloride, tetradecyl-9-enoyl chloride, hexadecyl-9-enoyl chloride, oleoyl chloride, eicosyl-9-enoyl chloride, docosyl-9-enoyl chloride, oxalyl chloride, malonyl chloride, succinyl chloride, glutaryl chloride, adipoyl chloride, pimelic acid chloride, suberic acid chloride, azelaic acid chloride, sebacic acid chloride, dodecanedioyl dichloride, tetradecanedioyl dichloride, hexadecanedioyl dichloride, 1-phenylcyclopropane carboxylic acid chloride, phenylacetyl chloride, 3-phenylpropionyl chloride, 4-phenylbutyryl chloride, 5-phenylvaleryl chloride, 6-phenylhexanoyl chloride, 7-phenylheptanoyl chloride, 8-phenyloctanoyl chloride, 2-methyl-8-phenyloctanoyl chloride, 2,2-dimethyl-8-phenyloctanoyl chloride, 9-phenylnonanoyl chloride, 10-phenyldecanoyl chloride, and 11-phenylundecanoyl chloride.

[0029] Preferably, the S1 organic solvent is tetrahydrofuran.

[0030] Preferably, the molar ratio of phenylhydrazine to triethylamine in S1 is 1:1.

[0031] Preferably, the amount of acyl chloride used in S2 is such that the molar ratio of acyl chloride groups to phenylhydrazine is slightly less than 1.

[0032] Preferably, the duration of the process of adding acyl chloride in S3 is 1-15 h, and the temperature is maintained in the range of 10-40°C.

[0033] Preferably, the end of the reaction in S3 is determined by the temperature of the system dropping to ambient temperature.

[0034] Preferably, the S4 organic solvent is tetrahydrofuran.

[0035] Further, the present application also provides a rubber composition comprising the hydrazide compound; the hydrazide compound is at least one of a mono-hydrazide compound or a di-hydrazide compound; preferably, both are used in proportion to achieve optimal performance; more preferably, the rubber composition comprises 0.1-7 parts by mass of the mono-hydrazide compound and 0.1-7 parts by mass of the di-hydrazide compound, based on 100 parts by mass of the rubber matrix.

[0036] Preferably, the rubber composition comprises 100 parts by mass of the rubber matrix, 20-70 parts by mass of carbon black, 2-6 parts by mass of zinc oxide, 1-4 parts by mass of stearic acid, 0.5-5 parts by mass of accelerator, 0.8-5 parts by mass of vulcanizing agent, 1-5 parts by mass of antioxidant, 0.5-2 parts by mass of protective wax, and 0.1-5 parts by mass of the hydrazide compound, based on 100 parts by mass of the rubber matrix.

[0037] Preferably, the mass fraction of natural rubber in the rubber matrix is greater than or equal to 50% of the total mass fraction of the rubber matrix.

[0038] Further, the mixing process for preparing the rubber composition is as follows:

[0039] K1: the rubber matrix is added to the internal mixer, and then carbon black, zinc oxide, stearic acid, antioxidant, protective wax, and the hydrazide compound are added for further mixing to obtain a first-stage rubber compound;

[0040] K2: the first-stage rubber compound is added to the internal mixer for further mixing to disperse the carbon black and the additives, to obtain a second-stage rubber compound;

[0041] K3: the vulcanizing agent and the accelerator are added to the second-stage rubber compound on the open mill for final mixing to obtain the rubber composition.

[0042] Preferably, the mixing time in K1 and K2 is 3-9 min, and the discharge temperature is 100-180℃.

[0043] Further, the present application also provides the use of the rubber composition in the preparation of tires; the use is the use of the hydrazide compound with a low melting point to achieve good dispersion in the rubber composition; or the use to improve the processing performance of the rubber compound; or the use to improve the dynamic modulus of the tire; or the use to balance the wet skid resistance and the rolling resistance of the tire.

[0044] Further, the present application also provides a tire, at least one component of which is prepared by vulcanizing the rubber composition. Preferably, the components of the tire include one of the tread, the sidewall, and the bead.

[0045] The present application has the following advantages:

[0046] (1) The hydrazide compound provided by the present application has a low melting point, and can achieve good dispersion in the rubber matrix within the mixing temperature range.

[0047] (2) The hydrazide compound provided by the present application can reduce the Mooney viscosity of the rubber composition, improve the processing performance, and has little effect on the scorch safety of the rubber compound at an appropriate amount.

[0048] (3) The monoacylhydrazine compound is more conducive to the maintenance of mechanical properties and the improvement of wet skid resistance, and the bisacylhydrazine compound is more conducive to the improvement of rolling resistance and the improvement of high-strain dynamic modulus.

[0049] (4) The monoacylhydrazine compound and the bisacylhydrazine compound provided by the application can be used in rubber compositions to achieve a tire with improved processing performance, improved dynamic modulus, balanced wet skid resistance and rolling resistance. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 The nuclear magnetic resonance hydrogen spectrum of lauryl hydrazide having the structure shown in formula (I) provided in Example 1 of the application.

[0051] Figure 2 The nuclear magnetic resonance hydrogen spectrum of stearyl hydrazide having the structure shown in formula (II) provided in Example 2 of the application.

[0052] Figure 3 The nuclear magnetic resonance hydrogen spectrum of oleic acid hydrazide having the structure shown in formula (III) provided in Example 3 of the application.

[0053] Figure 4 The mechanical properties (tensile strength Tb, elongation at break Eb, and tensile strength product Tb*Eb) of the rubber composition.

[0054] Figure 5 The dynamic storage modulus (G') of the rubber composition at low strain (0.1%) and high strain (15%) at 0°C.

[0055] Figure 6 The dynamic loss factor (tan δ) of the rubber composition at low strain (0.1%), high strain (15%) and peak strain (peak) at 0°C.

[0056] Figure 7 The dynamic storage modulus (G') of the rubber composition at low strain (0.1%) and high strain (15%) at 25°C.

[0057] Figure 8 The dynamic loss factor (tan δ) of the rubber composition at low strain (0.1%), high strain (15%) and peak strain (peak) at 25°C.

[0058] Figure 9 The dynamic storage modulus (G') of the rubber composition at low strain (0.1%) and high strain (15%) at 60°C.

[0059] Figure 10 The dynamic loss factor (tan δ) of the rubber composition at low strain (0.1%), high strain (15%) and peak strain (peak) at 60°C.

[0060] Figure 11 Comparison of the scorch time (tc10) and Mooney viscosity (expressed by minimum torque ML) of the rubber composition at different amounts of hydrazide compound. DETAILED DESCRIPTION

[0061] The application will be further described in conjunction with specific examples, but the scope of the application is not limited by these examples.

[0062] The raw materials used in the examples are described as follows, but are not limited to these materials:

[0063] Tetrahydrofuran: chromatographic grade, Shanghai Aldrin Biochemical Technology Co., Ltd., dehydrated before use.

[0064] Triethylamine: 99%, Acros Organics, USA, dehydrated before use.

[0065] Phenylhydrazine: analytical pure, 98%, Shanghai Aldrin Biochemical Technology Co., Ltd., dehydrated before use.

[0066] Lauroyl chloride: 98%, Shanghai Aldrin Biochemical Technology Co., Ltd.

[0067] Stearoyl chloride: chromatographic grade, 97%, Shanghai Aldrin Biochemical Technology Co., Ltd.

[0068] Oleoyl chloride: 80%, Shanghai Aldrin Biochemical Technology Co., Ltd.

[0069] Adipoyl chloride: 98%, Shanghai Aldrin Biochemical Technology Co., Ltd.

[0070] The instruments or reagents used in the examples are not specified by the manufacturer, but are all conventional products on the market.

[0071] Example 1

[0072] Lauroyl hydrazide

[0073] The preparation steps are as follows:

[0074] S1: 1000 mL three-necked flask, washed and dried in the oven, ready for use. Add a large stirrer to the three-necked flask, insert a ground constant pressure dropping funnel and a thermometer into two necks of the flask, and use the remaining neck to add solvent and starting reaction solution. During the reaction, plug the remaining neck with a ground plug.

[0075] S2: Add 500 mL of tetrahydrofuran, 48 mL of phenylhydrazine (~0.48 mol), and 67 mL of triethylamine (~0.48 mol) to the flask, and start stirring. Place the system in an ice water bath to reduce the temperature to below 4°C.

[0076] S3: 92 mL (~0.4 mol) lauroyl chloride was added dropwise into the flask through a constant pressure dropping funnel, the dropping rate was controlled to maintain the system temperature at 10-15 °C, and the dropping process lasted for about several hours.

[0077] S4: After the dropping was completed, the reaction was continuously stirred until the system temperature dropped to the ice bath environment temperature, and the reaction was considered to be completed.

[0078] S5: The reaction solution was filtered, the filter residue was washed with tetrahydrofuran, and the orange filtrate was collected.

[0079] S6: The filtrate was poured into excess distilled water, left overnight, separated into layers, and the upper layer solid was collected by filtration, and dried in a vacuum oven at 30 °C to a constant weight. The obtained orange yellow powder was formula (I), and the melting point was 81 °C.

[0080] Example 2

[0081] Stearic hydrazide

[0082] The preparation steps are as follows:

[0083] S1: A 1000 mL three-neck flask was washed and dried in an oven, and was ready for use. A large stirring bar was added into the three-neck flask, two necks were inserted into a grinding constant pressure dropping funnel and a thermometer, and the remaining neck was used to add solvent and starting reaction solution.

[0084] S2: 500 mL tetrahydrofuran, 30 mL phenylhydrazine (~0.3 mol), and 42 mL triethylamine (~0.3 mol) were added into the flask, and the stirring was started.

[0085] S3: The stearoyl chloride was melted into a liquid using a warm water bath, 83 g stearoyl chloride (~0.27 mol) was removed, and 50 mL tetrahydrofuran was used to configure a solution. The tetrahydrofuran solution of stearoyl chloride was added dropwise into the flask using a constant pressure dropping funnel. The dropping rate was controlled to maintain the system temperature at room temperature.

[0086] S4: After the dropping was completed, the reaction was continuously stirred overnight.

[0087] S5: The reaction solution was heated to 40 °C, and was filtered while hot. The orange filtrate was collected.

[0088] S6: The filtrate was transferred into a tin paper tray while hot, and a solid was precipitated after cooling. The upper layer tetrahydrofuran solvent was removed, and the obtained orange red blocky product was formula (II), and the melting point was 92 °C.

[0089] Example 3

[0090] Oleic acid hydrazide

[0091] The preparation steps are as follows:

[0092] S1: Wash and oven-dry a 1000mL three-necked flask. Place a large stirring bar in the flask. Insert a ground-joint constant-pressure dropping funnel and a thermometer into each of the two neck openings. The remaining opening is used for adding the solvent and the starting reaction solution. This should be plugged with a ground-joint stopper during the reaction.

[0093] S2: Add 500 mL of tetrahydrofuran, 48 mL of phenylhydrazine (~0.48 mol), and 67 mL of triethylamine (~0.48 mol) to the flask, start stirring, and place in an ice-water bath to reduce the system temperature to below 4°C.

[0094] S3: 163 mL (0.4 mol) of oleic acid chloride was added dropwise to the flask through a constant pressure dropping funnel. The dropping rate was controlled to maintain the system temperature at 10-15° C. The addition process lasted for several hours.

[0095] S4: After the dropwise addition is completed, the reaction is continued with stirring until the system temperature drops to the ice bath ambient temperature, which is considered to be the end of the reaction.

[0096] S5: The reaction solution was filtered, the filter residue was washed with tetrahydrofuran, and the orange filtrate was collected.

[0097] S6: Pour the filtrate into excess distilled water (~4 L), let it stand overnight, separate the layers, filter out the upper solid, and dry it in a vacuum oven at 30°C to constant weight. The resulting orange-yellow granular product has structural formula (III) and a melting point of 72°C.

[0098] Example 4

[0099] Adipic acid hydrazide

[0100] The preparation steps are as follows:

[0101] S1: Wash and oven-dry a 1000mL three-necked flask. Place a large stirring bar in the flask. Insert a ground-joint constant-pressure dropping funnel and a thermometer into each of the two neck openings. Use the remaining opening for adding solvent and the starting reaction solution.

[0102] S2: Add 500 mL of tetrahydrofuran, 71 mL of phenylhydrazine (~0.72 mol), and 101 mL of triethylamine (~0.72 mol) to the flask, start stirring, and place in an ice-water bath to cool the system to below 4°C.

[0103] S3: 44 mL (0.3 mol) of adipoyl chloride was added dropwise to the flask through a constant pressure dropping funnel. The dropping rate was controlled to maintain the system temperature at 10-15° C. The addition process lasted for about 1 hour.

[0104] S4: After the dropwise addition is completed, the reaction is continued with stirring until the system temperature drops to the ice bath ambient temperature, which indicates that the reaction is complete.

[0105] S5: The reaction solution was suction filtered, the filter residue was washed with tetrahydrofuran, and the orange filtrate was collected.

[0106] S6: The filtrate was volatilized under open to remove the tetrahydrofuran solvent, and concentrated to obtain an orange-red liquid, which was the structural formula (IV) and was a liquid at room temperature.

[0107] Application Examples 5-16 and Comparative Examples 1-12

[0108] The raw materials used in the application examples are described as follows:

[0109] Natural rubber: SVR3L, Shenglong Industry Co., Ltd.

[0110] Carbon black: N234, Hangzhou Zhizheqingquan Industry Co., Ltd.

[0111] Zinc oxide: Shijiazhuang Zhiyi Zinc Industry Co., Ltd.

[0112] Stearic acid: 1808, Natural Oleochemicals Sdn. Bhd., Malaysia.

[0113] Antioxidant 4020: Shandong Shangshun Chemical Co., Ltd.

[0114] Microcrystalline wax: OK11213, Baersime Special Chemicals (Suzhou) Co., Ltd.

[0115] Sulfur: Quzhou Ruituo Mining Co., Ltd.

[0116] Accelerator NS: Comai Chemical Co., Ltd.

[0117] Isophthalic dihydrazide: DC02, Otsuka Chemical Co., Ltd.

[0118] The rubber compositions were prepared by mixing according to the formulations shown in Tables 1 and 2 to obtain application examples 5-16 and comparative examples 1-12.

[0119] The mixing process is as follows:

[0120] K1: Set the starting temperature to 80°C and the rotation speed to 60 rpm, add the rubber matrix to the internal mixer, then add carbon black, zinc oxide, stearic acid, antioxidant, protective wax, and hydrazide compound for further mixing to obtain a first-stage mixed rubber;

[0121] K2: Set the starting temperature to 80°C and the rotation speed to 60 rpm, add the first-stage mixed rubber to the internal mixer, and continue mixing to further disperse the carbon black and additives to obtain a second-stage mixed rubber;

[0122] K3: Add the vulcanizing agent and accelerator to the second-stage mixed rubber on an open mill at 60°C for final mixing to obtain the rubber composition.

[0123] Table 1 Rubber composition formula (application example, mass parts)

[0124]

[0125]

[0126] Table 2 Rubber composition formula (comparative example, parts by mass)

[0127]

[0128] Test Case

[0129] The properties of the rubber compositions obtained in the above application examples and comparative examples were tested as follows:

[0130] (1) Mechanical properties test

[0131] Each rubber composition was vulcanized at 150°C for 20 minutes to produce 2mm thick strength sheets. Testing was conducted according to GB / T528-2009, "Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties," using ring specimens (14mm inner diameter, 16mm outer diameter) at a tensile rate of 500mm / min.

[0132] (2) Dynamic mechanical properties

[0133] Each rubber composition was vulcanized at 150°C for 20 minutes to produce a 2mm thick strong sheet. A benchtop drill press was used to cut out circular ring specimens (inner diameter 14mm, outer diameter 16mm). The shear strain sweep test was performed on the circular ring samples using TA's ARES-G2 rheometer; the test frequency was 0.5Hz, the test temperatures were 25°C, 60°C, and 0°C, and the strain sweep range was 0.001%-15%. The dynamic storage modulus (G') at 0.1% and 15% strain, and the loss factor (tanδ) at 0.1%, peak strain, and 15% strain were taken to compare the dynamic mechanical properties.

[0134] (3) Vulcanization characteristics

[0135] Tested according to GB / T 16584-1996, "Rubber — Determination of Vulcanization Characteristics Using a Rotorless Rheometer." Test conditions: 150°C for 60 minutes. Scorch time is indicated by tc10, and Mooney viscosity is indicated by minimum torque (ML).

[0136] The test results are shown in Table 3 (application example) and Table 4 (comparative example). For the convenience of comparison, the results are plotted as follows: Figures 4-11 .

[0137]

[0138]

[0139] Figures 4-11 Different shapes of icons represent different embodiments, upper triangle inverted triangle square diamond representing embodiments 1, 2, 3, 4, respectively; different black fill amount of the same shape icon represents the difference in the amount of use of the embodiment, no black fill half black fill full black fill representing the amount of 1 phr, 3 phr, 5 phr, respectively. Circle represents comparative example 10 (o), 12 (·). The star (☆) represents comparative examples 1-9, among which, comparative examples 5-9 (represented by no asterisk ☆) are 5 repeated experiments of rubber compositions without any hydrazide compound, and comparative examples 1-4 (☆ 1 , ☆ 2 , ☆ 3 , ☆ 4 ) have different sulfur and accelerator amounts than comparative examples 5-9, which are -50%, -30%, +30%, +50% of the amount of the latter, respectively. Comparative examples 1-9, on the one hand, reflect the trend of the change of the performance of the rubber composition with the crosslinking density, the purpose is to facilitate the comparison of the influence of the hydrazide on the performance of the rubber composition at the same crosslinking density, on the other hand, to determine the error range of the experiment, as shown by the gray bands in the figure, if the performance of the rubber composition after adding a certain hydrazide is located in or close to the gray band, it indicates that the influence of the hydrazide on the performance is very small, if the value of the performance of the rubber composition after adding a certain hydrazide is higher or lower than the gray band at the same crosslinking density, it indicates that the hydrazide will increase or decrease the value of the performance. Here, the crosslinking density is represented by the 300% modulus (M300) obtained by mechanical property test (tension), because at 300% strain, the filler network in the rubber composition has been destroyed, at this time, its modulus is dominated by the strength of the rubber network, that is, the crosslinking density.

[0140] Figure 4 are the test results of the mechanical properties of the rubber composition.

[0141] For Figure 4The tensile strength Tb-M300 graph, the gray band can be seen by the tensile strength of the comparative examples 1-9, first increases and then decreases with the increase of crosslinking density. The graph (upper triangle, inverted triangle, square) representing the tensile strength of application examples 5-7, 8-10, 11-13 (respectively adding different amounts of examples 1, 2, 3) are located or close to the gray band, indicating that the addition of lauryl hydrazide (example 1), stearic hydrazide (example 2), oleic hydrazide (example 3) has little effect on the tensile strength of the rubber composition. The values of application examples 15, 16 and comparative examples 10-12 are all below the gray band in the vertical horizontal coordinate direction (at the same crosslinking density), indicating that the addition of adipic dihydrazide (example 4) and isophthalic dihydrazide (comparative examples 10-12) has a relatively adverse effect on the tensile strength of the rubber composition. The value of application example 14 (◇) is located at the edge of the gray band, which represents the rubber composition added with 1 phr adipic dihydrazide, indicating that the addition of a small amount of adipic dihydrazide will not adversely affect the tensile strength.

[0142] For Figure 4 The elongation at break Eb-M300 graph, the values of application examples 5, 8, 11, 14 are located or close to the gray band, indicating that the addition of 1 phr of lauryl hydrazide, stearic hydrazide, oleic hydrazide and adipic dihydrazide will not affect the elongation at break of the rubber composition. The values of application examples 6, 7, 9, 10, 12, 13 deviate from the gray band to different degrees, indicating that the use of a large amount of monohydrazide compound is beneficial to the improvement of the elongation at break. The values of application examples 15, 16 and comparative examples 10-12 deviate from the gray band to different degrees, indicating that the use of dihydrazide compound will reduce the elongation at break of the rubber composition.

[0143] For Figure 4 The tensile strength Tb-M300 graph, the gray band can be seen by the tensile strength of the comparative examples 1-9, first increases and then decreases with the increase of crosslinking density. The graph (upper triangle, inverted triangle, square) representing the tensile strength of the rubber composition are located or close to the gray band, indicating that the addition of lauryl hydrazide (example 1), stearic hydrazide (example 2), oleic hydrazide (example 3) has little effect on the tensile strength of the rubber composition. The values of application examples 15, 16 and comparative examples 10-12 are all below the gray band in the vertical horizontal coordinate direction (at the same crosslinking density), indicating that the addition of adipic dihydrazide (example 4) and isophthalic dihydrazide (comparative examples 10-12) has a relatively adverse effect on the tensile strength of the rubber composition. The value of application example 14 (◇) is located at the edge of the gray band, which represents the rubber composition added with 1 phr adipic dihydrazide, indicating that the addition of a small amount of adipic dihydrazide will not adversely affect the tensile strength.

[0144] Generally, for mechanical properties, the addition of mono-hydrazide compounds has no significant effect on the tensile strength of the rubber composition, and higher amount of use will increase the elongation at break and tensile strength; while the addition of di-hydrazide compounds will decrease the tensile strength, elongation at break and tensile strength to some extent.

[0145] Figures 5-10 The test results of dynamic mechanical properties of the rubber composition. Figure 5 and 6 、 Figure 7 and 8 、 Figure 9 and 10 are the results of dynamic storage modulus (G’) and loss factor (tan δ) at 0°C, 25°C and 60°C, respectively. The loss factor at 60°C and 0°C are often used to characterize the rolling resistance and wet skid resistance, respectively. The lower tan δ@60°C, the lower rolling resistance; the higher tan δ@0°C, the better wet skid resistance.

[0146] at 0°C, Figure 5 show the dynamic storage modulus G’(0.1%) and G’(15%) at low strain (0.1%) and high strain (15%), respectively. For G’(0.1%), the values of application examples 5, 6, 11 and comparative examples 10, 11 are in the grey band area, and the values of other application examples and comparative examples are all above the grey band, which indicates that both mono-hydrazide and di-hydrazide compounds have good retention or improvement effect on the dynamic storage modulus of the rubber composition at low strain. For G’(15%), the values of application examples 8, 11, 12 are in the grey band area, the values of application examples 5, 6, 7 are lower than the grey band area, and the values of application examples 9, 10, 12 are slightly higher than the grey band area, which indicates that mono-hydrazide compounds have no obvious effect on the improvement of the dynamic storage modulus of the rubber composition at high strain, and the addition of example 1 (lauric hydrazide) reduces the value of G’(15%). The values of application examples 14, 15, 16 and comparative examples 10, 11, 12 are above the grey band, and the distance of their values above the grey band at the same crosslinking density is greater than that of application examples 9, 10, 12, which indicates that the addition of di-hydrazide compounds has obvious effect on the improvement of the dynamic storage modulus at high strain, and is better than the effect of mono-hydrazide compounds.

[0147] at 0°C, Figure 6The loss factor tan delta at low strain (0.1%), tan delta at high strain (15%) and tan delta peak are shown respectively. For tan delta at low strain (0.1%), the values of application examples 5-16 are all located in or above the grey band region at the same crosslinking density, and the values of comparative examples 10-12 are all located in or below the grey band region at the same crosslinking density, it can be seen that the addition of mono-hydrazide compound makes the tan delta at low strain (0.1%) of rubber composition at 0°C higher than that of di-hydrazide compound. For tan delta at high strain (15%) and tan delta peak, the values of comparative examples 10, 11 and 12 are lower than the grey band region at the same crosslinking density, indicating that the addition of isophthalic dihydrazide makes tan delta at high strain (15%) and tan delta peak decrease; the values of application examples 5-16 are all higher than the grey band region at the same crosslinking density, but the deviation of application examples 14, 15 and 16 from the grey band region is lower than that of other application examples, indicating that mono-hydrazide is more beneficial to improve tan delta at high strain (15%) and tan delta peak at 0°C than di-hydrazide compound.

[0148] In short, at 0°C, both mono-hydrazide and di-hydrazide compounds can effectively maintain or improve the dynamic storage modulus of rubber composition at low strain, but di-hydrazide is more beneficial to improve the dynamic storage modulus at high strain, and mono-hydrazide is more beneficial to improve the loss factor at 0°C, i.e. more beneficial to improve wet skid resistance.

[0149] At 25°C, Figure 7 The dynamic storage modulus at low strain (0.1%) and at high strain (15%) G' (0.1%) and G' (15%) are shown respectively. For G' (0.1%), the values of application examples 5-16 and comparative examples 10-12 are all located in or above the grey band region, indicating that both mono-hydrazide and di-hydrazide compounds have good effect on maintaining or improving the dynamic storage modulus of rubber composition at low strain. For G' (15%), the values of application examples 5, 6 and 7 are lower than the grey band region, and the values of other application examples and comparative examples 10-12 are all located in or above the grey band region, in addition, similar to the case at 0°C, the addition of di-hydrazide compound is better than mono-hydrazide compound in improving the dynamic storage modulus at high strain.

[0150] At 25°C, Figure 8The loss factor tan delta at low strain (0.1%), tan delta at high strain (15%) and tan delta peak are shown respectively. For tan delta (0.1%), the values of application examples 5-16 are all located in the grey band region, while the values of comparative examples 10-12 are lower than the grey band region at the same crosslinking density, and it can be seen that the addition of mono-hydrazide compound makes the tan delta (0.1%) of the rubber composition at 0°C higher than that of the bis-hydrazide compound. For tan delta (15%), the values of comparative examples 10-12 are located in the grey band, indicating that the isophthalic dihydrazide has no obvious effect on tan delta (15%); while the values of application examples 5-16 are all located above the grey band, indicating that the addition of examples 1-4 makes tan delta (15%) increase, and in addition, the increasing degree of mono-hydrazide is higher than that of bis-hydrazide. For tan delta peak, the values of comparative examples 10-12 are located below the grey band, indicating that the isophthalic dihydrazide makes the tan delta peak of the rubber composition decrease; while the values of application examples 5-16 are all located above the grey band, indicating that the addition of examples 1-4 makes tan delta peak increase, and again, the increasing degree of mono-hydrazide is higher than that of bis-hydrazide.

[0151] In short, both mono- and bis-hydrazide compounds can effectively maintain or improve the dynamic storage modulus of the rubber composition at low strain at 25°C, but bis-hydrazide is more beneficial to improve the dynamic storage modulus at high strain, and the loss factor of the rubber composition after the addition of mono-hydrazide is higher than that of bis-hydrazide at 25°C.

[0152] At 60°C, Figure 9 The dynamic storage modulus at low strain (0.1%) and at high strain (15%) G'(0.1%) and G'(15%) are shown respectively. For G'(0.1%), the values of application examples 5-16 and comparative examples 10-12 are all located in or above the grey band region, indicating that both mono- and bis-hydrazide compounds have good effect on maintaining or improving the dynamic storage modulus of the rubber composition at low strain. For G'(15%), the values of application examples 5, 6 and 7 are lower than the grey band region at the same crosslinking density, the values of application examples 8-13 are all located in the grey band region, and the values of application examples 14-16 and comparative examples 10-12 (two bis-hydrazide compounds) are all higher than the grey band region, indicating that the addition of bis-hydrazide compound is more beneficial to improve the value of dynamic storage modulus at high strain.

[0153] At 60°C, Figure 10The loss factor tan delta at low strain (0.1%), tan delta at high strain (15%) and tan delta peak are shown respectively. For tan delta (0.1%), the values of application examples 5-16 are all located in the grey band region, and the values of comparative examples 11, 12 are lower than the grey band region at the same crosslinking density, it can be seen that the addition of isophthalic hydrazide makes the tan delta (0.1%) of the rubber composition at 60°C decrease and is lower than the mono-hydrazide compound. For tan delta (15%), the values of comparative examples 10-12 are located in the grey band, indicating that isophthalic hydrazide has no obvious effect on tan delta (15%); the values of application examples 5-16 are all located in or above the grey band region, indicating that the addition of examples 1-4 makes tan delta (15%) unchanged or increased, but the increasing degree after the addition of mono-hydrazide is generally higher than that of di-hydrazide. For tan delta peak, the values of application examples 5-13 are located above the grey band, and the values of application examples 14-16 and comparative examples 10-12 (two di-hydrazide compounds) are all close to or located in the grey band region, indicating that di-hydrazide compound is more beneficial to keep or reduce tan delta peak at 60°C.

[0154] In short, at 60°C, both mono- and di-hydrazide compounds can effectively keep or improve the dynamic storage modulus of the rubber composition at low strain, but di-hydrazide is more beneficial to improve the dynamic storage modulus at high strain, and the loss factor of the rubber composition at 60°C is more likely to be kept or reduced after the addition of di-hydrazide, i.e. more beneficial to keep or improve the rolling resistance.

[0155] In general, for dynamic mechanical properties, both mono- and di-hydrazide compounds can effectively keep or improve the low strain dynamic modulus of the rubber composition, mono-hydrazide compound is more beneficial to improve the wet skid resistance, and di-hydrazide compound is more beneficial to improve the rolling resistance and improve the high strain dynamic modulus.

[0156] Figure 11 The results of the scorch time (tc10) and the Mooney viscosity (represented by minimum torque ML) of the rubber composition at different amounts of hydrazide compounds are compared. The diagonal shaded part in the figure is the result range of comparative examples 5-9. The scorch time reflects the processing safety of the rubber composition, and the shorter the scorch time, the worse the processing safety. The Mooney viscosity reflects the processing performance of the rubber composition, and the higher the Mooney viscosity, the worse the processing performance.

[0157] For Figure 11Scorch time tc10-hydrazide dosage pattern, when the dosage is 1 phr, the tc10 of Comparative Example 10 is the lowest and lower than Comparative Examples 5-9, indicating that the addition of adipic dihydrazide makes the processing safety of the rubber composition worse; the tc10 of Application Examples 5, 8, 11, 14 is also lower than Comparative Examples 5-9, but has increased to a certain extent compared with Comparative Example 10, indicating that the addition of Examples 1-4 to a certain extent improves the problem of the processing safety of the rubber composition after the addition of hydrazide. When the dosage is increased to 3 phr and 5 phr, the tc10 of the rubber composition after the addition of Examples 1-4 decreases to close to or even lower than the tc10 after the addition of isophthalic dihydrazide, indicating that the use of a large amount of Examples 1-4 also has an adverse effect on the processing safety.

[0158] For Figure 11 ML-hydrazide dosage pattern, the values of Application Examples 5-16 are all lower than Comparative Examples 5-9, and the values of Comparative Examples 10-12 are all higher than Comparative Examples 5-9, and are higher than the Application Examples under the same dosage, indicating that the addition of isophthalic dihydrazide makes the processing performance of the rubber composition worse, but the addition of Examples 1-4 effectively improves the processing performance of the rubber composition.

[0159] In general, the addition of Examples 1-4 can effectively improve the processing performance of the rubber composition, and the appropriate use has certain advantages in processing safety compared with isophthalic dihydrazide.

[0160] In summary, under the same crosslinking density, the addition of the hydrazide compounds described in the application can effectively improve the low-strain dynamic modulus of the rubber composition, wherein the mono-hydrazide compound is more conducive to the maintenance of mechanical properties and the improvement of wet skid resistance; the di-hydrazide compound is more conducive to the improvement of rolling resistance and the improvement of high-strain dynamic modulus; and under the appropriate use amount, the scorch safety and processing performance are better than the existing isophthalic dihydrazide. The use of mono-hydrazide compounds and di-hydrazide compounds in combination can achieve a tire with balanced processing performance, dynamic modulus improvement, wet skid resistance and rolling resistance, and specific application examples are shown in Table 5.

[0161] Table 5 Application Examples of mono-hydrazide compounds and di-hydrazide compounds in combination

[0162]

[0163] The above describes the embodiments and application examples of the application, and through the above description of the disclosed embodiments and application examples, the person skilled in the art can implement or use the application. Various modifications of these embodiments and application examples will be apparent to those skilled in the art. Therefore, the application will not be limited to these embodiments and application examples described herein, but will conform to the widest scope consistent with the schemes and novel points disclosed herein.

Claims

1. A rubber composition, characterized in that The rubber composition includes a hydrazide compound; the hydrazide compound is at least one of a monohydrazide compound of formula (a) and a bishydrazide compound of formula (b); The general formula of the monohydrazide compound or the bishydrazide compound is as follows: Monohydrazide compounds: Formula (a); Bisacylhydrazide compounds: Formula (b); Wherein, R1 is an alkyl group with 3-35 carbon atoms; R2 is an alkyl group with 0-30 carbon atoms.

2. The rubber composition according to claim 1, characterized in that The rubber composition comprises a hydrazide compound; the hydrazide compound is a monohydrazide compound and a bishydrazide compound.

3. The rubber composition according to claim 1, characterized in that: Based on 100 parts by mass of the rubber matrix, the rubber composition comprises 0.1-7 parts by mass of the monohydrazide compound and 0.1-7 parts by mass of the dihydrazide compound.

4. The rubber composition according to claim 1, characterized in that The melting point of the hydrazide compound is in the range of 15-180°C.

5. The rubber composition according to claim 1, characterized in that: The hydrazide compound was synthesized according to the following steps: S1: Add an organic solvent, an appropriate amount of phenylhydrazine, and an appropriate amount of triethylamine into a reaction vessel, start stirring, and lower the system temperature to below 4°C; S2: Add an appropriate amount of acyl chloride dropwise into the reaction vessel, controlling the dropwise addition rate to maintain the system at the reaction temperature; S3: After the addition is complete, continue stirring until the reaction is complete; S4: Filter the reaction solution with suction, and wash the filter residue with an organic solvent; S5: After collecting the filtrate and removing the organic solvent, the hydrazide compound is obtained.

6. The rubber composition according to claim 5, characterized in that The acyl chloride of S2 includes one or more of butyryl chloride, valeryl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride, nonanoyl chloride, decanoyl chloride, undecanoyl chloride, lauroyl chloride, tridecanoyl chloride, myristoyl chloride, pentadecanoyl chloride, palmitoyl chloride, heptadecanoyl chloride, stearoyl chloride, nonadecanoyl chloride, arachidoyl chloride, heneicosanoyl chloride, and behenoyl chloride; Alternatively, one or more of oxalyl chloride, maloyl chloride, succinyl chloride, glutaryl chloride, adipoyl chloride, pimeloyl chloride, suberyl chloride, azelayl chloride, sebacoyl chloride, dodecanedioyl chloride, tetradecanedioyl chloride, and hexadecanedioyl chloride.

7. The rubber composition according to claim 5 or 6, characterized in that The organic solvent in S1 is tetrahydrofuran; and / or, the molar ratio of phenylhydrazine to triethylamine is 1:08-1.2; and / or, the amount of acyl chloride used in S2 is such that the molar ratio of the acyl chloride group to the phenylhydrazine is less than 1; And / or, the duration of the process of adding the acyl chloride dropwise in S2 is 1-15 hours, and the temperature is maintained in the range of 10-40°C; And / or, the termination of the reaction in S3 is determined by the system temperature dropping to ambient temperature.

8. The rubber composition according to claim 1, wherein Based on 100 parts by mass of the rubber matrix, the rubber composition comprises 100 parts of the rubber matrix, 20-70 parts of carbon black, 2-6 parts of zinc oxide, 1-4 parts of stearic acid, 0.5-5 parts of an accelerator, 0.8-5 parts of a vulcanizing agent, 1-5 parts of an antioxidant, 0.5-2 parts of a protective wax, and 0.1-5 parts of a hydrazide compound.

9. The rubber composition according to claim 8, characterized in that The mass fraction of natural rubber in the rubber matrix is ​​greater than or equal to 50% of the total mass fraction of the rubber matrix.

10. A method for preparing the rubber composition according to any one of claims 8 to 9, characterized in that: The steps include: K1: Add the rubber matrix into the internal mixer, then add carbon black, zinc oxide, stearic acid, antioxidant, protective wax, and hydrazide compound and continue mixing to obtain a mixed rubber; K2: Add the first-stage rubber mix to the internal mixer and continue mixing to further disperse the carbon black and additives to obtain the second-stage rubber mix; K3: adding a vulcanizing agent and an accelerator to the second-stage mixed rubber on an open mill and performing final mixing to obtain the rubber composition.

11. The method according to claim 10, characterized in that The mixing time of K1 and K2 is 3-9 min, and the binder removal temperature is 100-180°C.

12. Use of the rubber composition according to any one of claims 1 to 9 in tire preparation, wherein the rubber composition has a low melting point and can achieve a good dispersion effect.

13. Use of the rubber composition according to any one of claims 1 to 9 in tire preparation, wherein the use is for improving the processing performance of the rubber compound.

14. Use of the rubber composition according to any one of claims 1 to 9 in the preparation of a tire, wherein the use is to improve the dynamic modulus of the tire.

15. Use of the rubber composition according to any one of claims 1 to 9 in the preparation of a tire, wherein the use is to achieve a balance between wet skid resistance and rolling resistance in the tire.

16. A tire, characterized in that: At least one of the components of the tire is prepared by vulcanizing the rubber composition according to any one of claims 1 to 9.

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