A method for replacing accelerator DPG in white carbon black formulation compounds

Abstract

The application discloses a method for replacing accelerator DPG in white carbon black formula rubber, and belongs to the technical field of rubber processing. The method adopts a binary acid diacylhydrazine compound or a mixture thereof with the structure of formula I, which is added in the master mixing stage of rubber and filler, and completely or partially replaces the traditional diphenyl guanidine accelerator DPG. The amount of the binary acid diacylhydrazine is 0.3-1.5 parts by mass per 100 parts by mass of rubber. The replacement method provided by the application eliminates the risk of toxic aniline smoke generated by the decomposition of DPG in the mixing process, and can reduce the hysteresis loss and compression heat build-up of the rubber compound, improve the resilience and wear resistance, and has low raw material cost, process safety and environmental protection compared with other replacement schemes, and is suitable for white carbon black reinforced tire tread rubber and other products.

Description

Technical Field

[0001] This invention belongs to the field of rubber processing technology, and specifically relates to a method for replacing the accelerator DPG in silica-based rubber compounds. Background Technology

[0002] The accelerator DPG, chemically known as 1,3-diphenylguanidine, is one of the oldest accelerators used in the rubber industry. Previously, it was mainly used in natural and synthetic rubber as a medium-speed vulcanization accelerator. However, due to its low thermal decomposition temperature (generally considered to begin decomposition above 160°C, which happens to be the temperature range during filler and rubber masterbatch mixing), it easily decomposes during rubber compounding, releasing volatile, toxic, and carcinogenic aniline fumes. Furthermore, aniline in the compound continues to be released in relatively open working environments such as subsequent semi-finished product processing and even tire molding, posing a health hazard to workers. Therefore, many countries worldwide have increasingly stringent restrictions on the use of DPG. On the other hand, the DPG production process itself carries certain safety risks and typically generates large amounts of wastewater. Therefore, there has been a strong call within the industry to reduce its use and gradually phase it out. However, with the promotion of green tire technology, silica is being used extensively in rubber tires, especially passenger car tire treads. Consequently, the amount of accelerator DPG is increasing. This is because DPG primarily functions as a coupling aid in rubber compositions where silica is the main reinforcing filler. Utilizing its nucleophilic basic groups on its guanidine groups, it adsorbs onto the electrophilic hydroxyl groups on the silica surface, reducing the polarity of the silica surface, increasing compatibility with rubber, and promoting uniform dispersion of silica. Simultaneously, it helps silane coupling agents undergo hydrolysis to produce silanol groups, which then react with the hydroxyl groups on the silica surface to form a strong siloxane interface, thus achieving better dispersion of silica and reinforcement of the rubber. Therefore, adding both accelerator DPG and silane coupling agents simultaneously during the masterbatch stage of rubber and silica mixing has become the main mixing process for low rolling resistance passenger car tire treads.

[0003] Therefore, regarding the role of accelerator DPG in the masterbatch stage of silica compounding, providing a safe, low-toxicity compound or compound composition with good thermal stability, which also reduces the energy loss factor of rubber composition at 60℃—a dynamic mechanical property characteristic value positively correlated with tire rolling resistance and compression heat generation—a dynamic mechanical property characteristic value positively correlated with tire durability and fatigue resistance, improves resilience and wear resistance, and has good industrial economics, to completely replace DPG used as an accelerator in the masterbatch stage of rubber compositions where silica is the main reinforcing filler, is a problem that urgently needs to be solved in the rubber industry. Summary of the Invention

[0004] The technical problem this invention aims to solve is to provide a safe, low-toxicity, thermally stable method to replace DPG, which can reduce hysteresis loss in rubber compounds. A dicarboxylic acid dihydrazide compound with the structure of Formula I is added during the masterbatch stage to replace DPG. This invention provides the following technical solution: Through research and development, the inventors discovered that dicarboxylic acid diacid hydrazides are also weakly basic, especially with their outermost amine groups exhibiting strong nucleophilicity. These compounds can similarly aid in the dispersion of silica in rubber and assist silane coupling agents in hydrolysis to produce silanol groups. Therefore, diacid hydrazides can be mixed with silica and silane coupling agents during the masterbatch stage of silica-based rubber formulations, completely replacing DPG. This process similarly helps the silane coupling agent hydrolyze to produce silanol groups, which then form covalently bonded siloxanes with the hydroxyl groups on the silica surface, ultimately creating a strong bond with the rubber. Furthermore, diacid hydrazides can be adsorbed onto the hydroxyl groups on the silica surface, reducing surface polarity and making it easier for them to undergo silanization reactions with the silanol groups on the hydrolyzed silane coupling agent. This facilitates the dispersion of silica particles in the rubber and the establishment of a cross-linking network, resulting in a reinforcing effect. On the other hand, using dihydrazide compounds has another advantage: they readily react with oxidation products at the ends of rubber molecular chains, such as aldehyde and ketone groups, to form grafts that then tightly adsorb onto the filler surface. This further reduces hysteresis loss, compression heat generation, and rolling resistance. Simultaneously, it can appropriately improve the strength and abrasion resistance of the rubber composition after vulcanization, and enhance its post-aging properties. These are advantages that rubber compositions using only the accelerator DPG do not possess. The specific implementation method is as follows: In rubber compositions where silica is the primary reinforcing filler, a mixture of one or more compounds with the following formula I structure may be used to replace the diphenylguanidine accelerator DPG used in the masterbatch stage of the formulation:

[0005] Formula I 1) The compound or mixture of Formula I is a dicarboxylic acid dihydrazide structure, wherein R is a single compound of a straight-chain or branched saturated or unsaturated alkane or aromatic hydrocarbon with 2 to 10 carbon atoms, or a mixture of two or more dicarboxylic acid dihydrazides.

[0006] 2) In a rubber composition comprising 100 parts by weight of rubber, the amount of the above compound or mixture is 0.3 to 1.5 parts; 3) Preferably, the compound of Formula I is a straight-chain saturated aliphatic hydrocarbon dicarboxylic acid dihydrazide, wherein R is a straight-chain saturated aliphatic hydrocarbon with 2 to 6 carbon atoms. More preferably, a mixture of straight-chain aliphatic hydrocarbon dicarboxylic acid dihydrazides with R having 2 to 4 carbon atoms (hereinafter referred to as mixed dicarboxylic acid dihydrazides) is selected, including but not limited to the following typical component ranges: Succinic dihydrazide: 10~30% Glutaric acid dihydrazide: 40~80% Adipic acid dihydrazide: 0~30% Preferably, a single compound or a mixture of two or more compounds of the above Formula I structure is used to completely replace the diphenylguanidine accelerator DPG in the masterbatch stage formulation, with a dosage range of 0.5 to 1.5 parts; more preferably, a mixed dicarboxylic acid dihydrazide is used to completely replace DPG, with a dosage range of 0.6 to 1.0 parts.

[0007] Preferably, if only partially replacing the diphenylguanidine accelerator DPG in the masterbatch stage formulation to obtain better vulcanizate performance, when the amount of DPG is more than 0.4 parts, the amount of a single compound or a mixture of two or more compounds of the above-mentioned Formula I structure is in the range of 0.3 to 0.8 parts. Preferably, a mixed dicarboxylic acid dihydrazide is used, and the amount range is 0.4 to 0.6 parts.

[0008] Preferably, the method of using a single compound or a mixture of two or more compounds of the above-mentioned Formula I structure to replace the diphenylguanidine accelerator DPG is to add it together with other additives from the mastering stage, such as silica, silane coupling agent, zinc oxide, stearic acid and processing oil, into an internal mixer for normal mixing during the mastering (first stage mixing) of rubber and filler, and then operate according to the normal mixing procedure until the final mixing stage of the compound is completed.

[0009] Preferably, the rubber composition with silica as the main reinforcing filler should contain synthetic or natural diene rubber, silica and silane coupling agent, and the amount of silica should be determined as needed, not exceeding 40% of the silica by mass.

[0010] Preferably, the method for manufacturing the above-mentioned diacid dihydrazide compound of Formula I involves reacting the esterified diacid with hydrazine hydrate in a solvent via a hydrazinolysis reaction. After solid-liquid separation, the diacid dihydrazide compound or mixture of Formula I can be obtained. Particularly low, the method for manufacturing the above-mentioned mixed diacid dihydrazide involves first esterifying a mixed diacid (mainly composed of glutaric acid, succinic acid, and adipic acid in non-fixed proportions), a byproduct of industrial adipic acid production, with methanol to form a mixed diacid dimethyl ester. Then, it undergoes a hydrazinolysis reaction with hydrazine hydrate in methanol to produce mixed diacid dihydrazides (glutaric acid dihydrazide, succinic acid dihydrazide, and adipic acid dihydrazide in non-fixed proportions). After solid-liquid separation and drying, the mixed diacid dihydrazides can be obtained.

[0011] Compared to other compounds or mixtures with Formula I structure, mixed diacid diacid hydrazides have readily available and cost-controllable raw materials. Furthermore, compared to the accelerator DPG, the masterbatch process of rubber compositions does not emit toxic aniline fumes due to thermal decomposition. In particular, the production process is safer than DPG, and wastewater discharge is significantly reduced. Mixed diacid hydrazides are more efficient in accelerating the silanization reaction between coupling agents and silica. In the masterbatch stage, only 50-80% of the DPG amount is needed to achieve comparable or even better silica dispersion and reinforcing effects. In formulations containing a certain proportion of natural rubber, they can significantly reduce the loss factor and compression heat of the vulcanized rubber, resulting in lower rolling resistance, improved wear resistance, and enhanced durability of the tires.

[0012] This invention has at least the following technical effects: 1. This invention avoids the aniline fumes produced by DPG decomposition, making it environmentally friendly and safe; 2. The dicarboxylic acid dihydrazide of the present invention can help disperse silica, assist in the hydrolysis of silane coupling agents, and graft onto the ends of rubber molecular chains, thereby reducing hysteresis loss; 3. This invention requires a small dosage (only 50-80% of DPG is needed to achieve better results) and has significant effects.

[0013] 4. The raw material cost of this invention is low, the production process is safe, and wastewater is minimal. Attached Figure Description

[0014] Figure 1 Dynamic mechanical property testing of the three-adhesive compound provided in the embodiments of the present invention: DMA and compression heat generation; Figure 2 Dynamic mechanical property testing of styrene-butadiene rubber compound provided in this embodiment of the invention: DMA and compression heat generation.

[0015] Figure 3 Dynamic mechanical property testing of the styrene-butadiene rubber (zinc oxide and stearic acid are added in the second stage) compound provided in the embodiments of the present invention: DMA and compression heat generation. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] As shown in Tables 1-2, in a preferred embodiment of the present invention, the formulation of the control group rubber compound in the present invention refers to the currently popular formulations of three rubber compounds reinforced with silica (control group 1) or styrene-butadiene rubber (control groups 2 and 3) for passenger tire treads. In these embodiments, different types of Formula I compounds completely replace DPG in the masterbatch, wherein: In the formulation using three types of rubber, 1.3 parts of the accelerator DPG in the masterbatch stage were removed and replaced with 0.8 parts of each of the three dihydrazide auxiliaries, constituting Examples 1-3. Example 1 used a mixed dicarboxylic acid dihydrazide, Example 2 used terephthalic acid dihydrazide, and Example 3 used isophthalic acid dihydrazide. Due to the reduction in the total amount of accelerator, the anti-scorching agent CTP was removed from the final rubber formulations of Examples 1-3 to maintain a vulcanization rate comparable to the control group. Control groups 2-1 and 2-2, as well as Examples 4-8, are simulated styrene-butadiene rubber tread formulations. In normal formulations, 1.5 parts of accelerator DPG are used in the masterbatch stage, i.e., control group 2-2. To demonstrate the effect of accelerator DPG in the masterbatch, DPG was deliberately omitted in the masterbatch stage, and no auxiliary agents for silanization of silica were added, forming control group 2-1. Examples 4-8 all use accelerator DPG in the masterbatch stage, but use dihydrazide-based auxiliary agents to achieve the effect of silanization. Specifically, Example 4 used 0.8 parts of terephthalic acid dihydrazide, Example 5 used 0.8 parts of isophthalic acid dihydrazide, and Examples 6-8 used 0.6, 0.8, and 1.0 parts of mixed dicarboxylic acid dihydrazide, respectively. Considering the potential interaction between zinc oxide and silica, control groups 3-1 (without DPG accelerator and no other silanization aids added) and 3-2 (normal formulation, retaining 1.5 parts of DPG accelerator in the masterbatch) were designed with the same full silica formulation. Examples 9-13, which are the same as those for styrene-butadiene rubber examples 4-8, replaced DPG in the masterbatch stage with dihydrazide. However, in all control groups 3-1, 3-2 and examples 9-13, zinc oxide and stearic acid were added in the refining stage after masterbatch, while other aspects remained unchanged. In example 9, 0.8 parts of dihydrazide terephthalate were added in the masterbatch stage; in example 10, 0.8 parts of dihydrazide isophthalate were added in the masterbatch stage; and in examples 11-13f, 0.6, 0.8 and 1.0 parts of mixed dihydrazide terephthalate were added in the masterbatch stage, respectively. To maintain consistency, the control groups 2-1, 2-2, 3-1 and 3-2, as well as Examples 4 to 13, of all styrene-butadiene rubber formulations did not use the anti-scorching agent CTP. The specific formulations are shown in Tables 1, 2 and 3 below.

[0018] Table 1 Test Formulation of Three-Adhesive Composite Silica

[0019] Table 2 Test Formulation of Styrene-Butadiene Rubber Carbon Black

[0020] Table 3 Test Formulation of Styrene-Butadiene Rubber (Zinc Oxide and Stearic Acid Added in the Second Stage)

[0021] Experimental materials: NR Vietnam No. 20 standard rubber; SSBR-2564S, Dushanzi Petrochemical; BR9000, Yanshan Petrochemical; N-330 carbon black, Cabot Corporation; 165MP silica, Zhuzhou Xinglong New Materials; Si-69, Jianghan New Materials; zinc oxide, stearic acid, sulfur, accelerator, antioxidant, anti-scorching agent, protective wax and aromatic oil, etc., are all commercially available products; Compound I is selected from mixed dicarboxylic acid dihydrazide HY-01B and terephthalic acid dihydrazide HY-01A produced by Henan Yongxin Chemical Co., Ltd., and commercially available isophthalic acid dihydrazide RK-602.

[0022] Equipment and Instruments: 1L internal mixer (Qingdao University of Science and Technology); 6-inch open mill and 50-ton flat vulcanizing agent (Qingdao Hainuotai Technology Co., Ltd.); Mooney viscometer and rotorless vulcanizer (Shanghai Nuojia Instrument Co., Ltd.); electronic tensile testing machine (Qingdao Hainuotai Technology Co., Ltd.); infrared spectrometer (Agilent Technologies Co., Ltd.); Dynamic thermomechanical analyzer (DMA) EPLEXOR-150 N (Netzsch GmbH, Germany); rubber processing analyzer (RPA) (Alpha Technologies Inc., USA); compression heat testing machine (High-speed rail testing instrument Co., Ltd.).

[0023] The mixing processes for the rubber compounds in the examples and control groups are as follows: After preheating the internal mixer, three types of rubber and stearic acid were added. In the example, different proportions of compounds of formula I, II, and III were added together. The temperature was maintained at 100°C for 40 seconds. Then, half of the silica and Si-69 were added and maintained for 60 seconds. The remaining silica, carbon black, zinc oxide, antioxidant, oil, DPG (control group), and wax were added. The temperature was maintained at 150°C for 60 seconds. The total mixing time was about 5.5 minutes. After the rubber was discharged, the mixture was sheeted and cooled on a two-roll mill. The mixture was then re-mixed once for a total time of 2.5 minutes, reaching a temperature of 135°C. After the rubber was discharged and sheeted and cooled on a two-roll mill, the final mixing was carried out on a two-roll mill, with the addition of sulfur, accelerator combination, and anti-scorching agent (control group 1).

[0024] The mixing process for styrene-butadiene rubber (SBR) is the same as that for three-adhesive blends. For SBR (with zinc oxide and stearic acid added in the second stage), the only difference is that zinc oxide and stearic acid are added in the second stage of mixing, while the rest is the same as that for three-adhesive blends.

[0025] The results of the processing and mechanical properties tests of the compound are shown in the table below.

[0026] Table 4 Test data for silica blended with three types of adhesives

[0027] Table 5 Test data of styrene-butadiene rubber silica

[0028] Table 6 Test data for styrene-butadiene rubber silica (zinc oxide and stearic acid are added in the second stage).

[0029] Note: The control group and the example compound were vulcanized separately with a flat vulcanizing agent at 150℃, with the t90 time increased by 30% according to the detected time. The DMA test was set to a tensile mode with a scanning temperature range of -65℃ to 65℃, static stress set to 80N, dynamic stress set to 40N, static strain set to 7%, dynamic strain set to 0.25%, heating rate set to 2℃ / min, and frequency set to 10Hz. The heat of compression was tested according to the method specified in GB / T1687.3-2016.

[0030] An aging test was conducted in an oven at 100℃ for 72 hours. The performance after aging is shown in the table below.

[0031] Table 7 Test data for aging adhesive made with three types of mortar and silica

[0032] Table 8 Test data for styrene-butadiene rubber with silica aging

[0033] Table 9. Test data of aging rubber of styrene-butadiene rubber with silica (zinc oxide and stearic acid added in the second stage).

[0034] The test results above show that using a single compound or mixture of Formula I can completely replace the accelerator DPG used in the masterbatch stage of silica-reinforced rubber formulation, achieving the same or better dispersion and coupling effects for silica. The mechanical properties of the vulcanizate are comparable or better, and it reduces the loss factor, compression heat generation, and abrasion, thereby reducing the rolling resistance of the tire and extending its durability. In particular, the mixed dicarboxylic acid dihydrazide in Formula I compounds has the best improvement effect and has little impact on the processing performance of the compound.

[0035] Results analysis: (1) Three-adhesive combined with silica formulation in Examples 1-3 The formula is shown in Table 1, and the performance is shown in Table 4. Figure 1When DPG was replaced by mixed dicarboxylic acid dihydrazide (Example 1), terephthalic acid dihydrazide (Example 2), and isophthalic acid dihydrazide (Example 3), the results showed that the static mechanical properties of the vulcanizates before and after aging in each example were comparable to or better than those in the control group. In particular, Example 1 showed the best effect in reducing compression heat and improving resilience.

[0036] (2) Examples 4-8 Styrene-butadiene rubber silica formulation The formula is shown in Table 2, and the performance is shown in Table 5. Figure 2 Control group 2-1 represents the extreme case where no DPG accelerator was added during the masterbatch stage. It was observed that the mechanical properties of this compound after vulcanization were significantly inferior to those of control group 2-2 both before and after aging, indicating insufficient silanization of the silica and inadequate reinforcement. However, when different amounts of mixed dicarboxylic acid diacid hydrazide (Examples 6-8), terephthalic acid diacid hydrazide (Example 4), and isophthalic acid diacid hydrazide (Example 5) were used to replace DPG in the masterbatch stage, the mechanical properties of the compounds after vulcanization were comparable to those of control group 2-2. In terms of dynamic mechanical properties, all examples were superior to control group 2-2, especially the mixed dicarboxylic acid diacid hydrazide, which showed the best effect in reducing the 60°C loss factor within the range of 0.6-1.0 parts (Examples 7-9).

[0037] (3) Examples 9-13 Styrene-butadiene rubber (zinc oxide and stearic acid are added in the second section later) The formula is shown in Table 3, and the performance is shown in Table 6. Figure 3 Control group 3-1 represents the extreme case where no DPG accelerator was added to the masterbatch. It was observed that the mechanical properties of this compound after vulcanization were significantly inferior to those of control group 3-2 both before and after aging, indicating that the silanization of the silica was insufficient and the reinforcing effect was not fully realized. However, when different amounts of mixed dicarboxylic acid dihydrazides (Examples 10-13) and terephthalic acid dihydrazides (Example 9) and isophthalic acid dihydrazides (Example 10) were used to replace DPG in the masterbatch stage, the mechanical properties of the compounds after vulcanization were comparable to those of control group 3-2. In terms of dynamic mechanical properties, all examples were superior to control group 3-2; especially Examples 10-13, which showed better strength, and also demonstrated superior performance in reducing the 60°C loss factor and compression heat generation.

[0038] Aging performance: Tables 7, 8 and 9 show the performance data after aging at 100℃ for 72h. The tensile strength and tensile volume retention of each embodiment are better than those of the control group.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for replacing the accelerator DPG in a silica-based rubber compound, characterized in that, In rubber compositions with silica as the main reinforcing filler, a mixture of one or more compounds with the structure of Formula I below is used to replace the diphenylguanidine accelerator DPG used in the masterbatch stage of the formulation. ； Formula I Wherein, the compound or mixture of Formula I is a dicarboxylic acid dihydrazide structure, wherein R is a single compound or a mixture of two or more dicarboxylic acid dihydrazides of a straight-chain or branched saturated or unsaturated alkane or aromatic hydrocarbon with 2 to 10 carbon atoms; the amount of the compound or mixture is 0.3 to 1.5 parts per 100 parts by weight of rubber.

2. The method for replacing DPG accelerator in silica-formulated rubber compounds according to claim 1, characterized in that, Compounds with Formula I are straight-chain saturated aliphatic hydrocarbon dicarboxylic acid dihydrazide structures, where R is a straight-chain saturated aliphatic hydrocarbon with 2 to 6 carbon atoms.

3. The method for replacing the accelerator DPG in silica binder according to claim 2, characterized in that, The compound of Formula I is a mixture of straight-chain saturated aliphatic hydrocarbon dicarboxylic acid dihydrazides with R having 2 to 4 carbon atoms. It is called mixed dicarboxylic acid dihydrazides, and its components range as follows: succinic acid dihydrazide 10% to 30%, glutaric acid dihydrazide 40% to 80%, and adipic acid dihydrazide 0% to 30%.

4. The method for replacing DPG accelerator in silica-formulated rubber compounds according to claim 1, characterized in that, The diphenylguanidine accelerator DPG in the masterbatch stage formulation is completely replaced by a single compound or a mixture of two or more compounds of the structure described in Formula I, wherein the amount of the compound or mixture is 0.5 to 1.2 parts.

5. A method for replacing the accelerator DPG in a silica-formulated rubber compound according to claim 4, characterized in that, The mixed dicarboxylic acid dihydrazide is used to completely replace DPG, and the amount of the mixed dicarboxylic acid dihydrazide is 0.6 to 1.0 parts.

6. A method for replacing DPG accelerator in a silica-formulated rubber compound according to claim 1, characterized in that, When a mixture of one or more compounds of Formula I is used to partially replace the diphenylguanidine accelerator DPG in the masterbatch stage formulation, and the amount of retained DPG is 0.4 parts or more, the amount of the single compound or mixture of two or more compounds of Formula I is 0.3 to 0.8 parts.

7. A method for replacing DPG accelerator in a silica-formulated rubber compound according to claim 6, characterized in that, The mixed dicarboxylic acid dihydrazide is used to partially replace DPG, and the amount of the mixed dicarboxylic acid dihydrazide is 0.4 to 0.6 parts.

8. A method for replacing the accelerator DPG in a silica-formulated rubber compound according to any one of claims 1 to 7, characterized in that, The method of using a single compound or a mixture of two or more compounds of the structure described in Formula I to replace the diphenylguanidine accelerator DPG involves adding it together with silica, silane coupling agent, zinc oxide, stearic acid and processing oil into an internal mixer for normal mixing during the mastering stage of rubber and filler. Then, the normal mixing procedure is followed until the final mixing stage of the compound is completed.

9. A method for replacing the accelerator DPG in a silica-formulated rubber compound according to claim 1, characterized in that, The rubber composition using silica as a reinforcing filler contains synthetic or natural diene rubber, silica, and silane coupling agent, wherein the amount of silica does not exceed 40% of the silica by weight.

10. A method for replacing the accelerator DPG in a silica-formulated rubber compound according to claim 1, characterized in that, The method for manufacturing the dicarboxylic acid dihydrazide compound of Formula I is to react the ester of the dicarboxylic acid with hydrazine hydrate in a solvent by hydrazine hydrolysis, and the dicarboxylic acid dihydrazide compound or mixture of Formula I can be obtained after solid-liquid separation. The method for manufacturing the mixed dicarboxylic acid dihydrazide is to first esterify the mixed dicarboxylic acid, a byproduct of the industrial production of adipic acid, with methanol to form a mixed dicarboxylic acid dimethyl ester, and then perform a hydrazinolysis reaction with hydrazine hydrate in methanol to generate a mixture of dicarboxylic acid dihydrazide. After solid-liquid separation and drying, the mixed dicarboxylic acid dihydrazide can be obtained.

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