A flame-retardant and antistatic rubber V-belt and its preparation method

Abstract

The present invention relates to a flame-retardant and antistatic rubber V-belt, which is characterized in that, calculated by weight parts, it comprises: 60-80 parts of nitrile rubber, 30-50 parts of styrene-butadiene rubber, 25-45 parts of ultrafine calcium carbonate, 16-32 parts of modified silica, 14-28 parts of flame retardant, 10-15 parts of softener, 6-12 parts of antioxidant, 1.5-3.5 parts of antistatic agent, 3-8 parts of vulcanizing agent and 1-3 parts of vulcanization accelerator. Compared with traditional rubber materials, the modified silica added in the present invention is prepared by surface chemical cross-linking modification of silica, and groups such as pyrimidine, thioether and amide bonds enriched in its cross-linked structure not only increase the flame retardancy and antistatic property of the composite rubber, but also have better improvement in mechanical properties and other basic properties.

Description

Technical Field

[0001] The invention relates to the field of rubber materials, and in particular to a flame-retardant and antistatic rubber V-belt and a preparation method thereof. Background Art

[0002] The rubber V-belt is composed of a covering layer, a tension layer, a cord layer, and a compression layer. The covering layer is made of a bias-cut rubber canvas wrapped around it, which plays a connecting role, protects other components from damage, and increases the stiffness of the V-belt. The rubber material of the V-belt covering layer needs to have certain properties such as wear resistance, heat resistance, aging resistance, and viscosity. The transmission belt, also known as a conveyor belt, is the transmission medium in the transmission belt system. The transmission belt system is a type of transmission system. The system will include two or more pulleys with a transmission belt on them. The pulley can rotate the transmission belt without restriction. There will be one or more power drives in the pulleys to allow the transmission belt to move and carry the materials transmitted on the transmission belt. The V-belt is a V-shaped belt, which is a unique conveyor belt. The V-belt is an important mechanical power transmission component, which is widely used in agricultural machinery, engineering machinery, automobiles, trains and other fields that require transmission and speed change. It is the main consumable material for various mechanical power transmission and speed change in the world.

[0003] Rubber is an essential material for manufacturing aircraft, warships, automobiles, tractors, harvesters, irrigation and drainage machinery, medical equipment, etc. Rubber can be divided into natural rubber and synthetic rubber. A few varieties of synthetic rubber have similar properties to natural rubber, but most are different from natural rubber. However, both are highly elastic polymer materials, and generally need to be vulcanized and processed before they have practicality and use value. Existing rubber V-belts are mainly made of rubber, so they are prone to static electricity during use. After static electricity accumulates, it will absorb dust, aggravate the slippage of the rubber V-belt, and cause static electricity discharge. They are not suitable for special working occasions where static electricity accumulation is prone to cause discharge. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a flame retardant and antistatic rubber V-belt and a preparation method thereof.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a flame retardant antistatic rubber V-belt, calculated by weight, comprising:

[0007] 60-80 parts of nitrile rubber, 30-50 parts of styrene-butadiene rubber, 25-45 parts of ultrafine calcium carbonate, 16-32 parts of modified white carbon black, 14-28 parts of flame retardant, 10-15 parts of softener, 6-12 parts of antioxidant, 1.5-3.5 parts of antistatic agent, 3-8 parts of vulcanizing agent and 1-3 parts of vulcanization accelerator.

[0008] Further, the grade of the nitrile rubber includes any one of NBR1704, NBR2707, NBR2907, and NBR3355; the grade of the styrene-butadiene rubber includes any one of SBR1502, SBR1500, and SBR1712.

[0009] Further, the particle size of the ultrafine calcium carbonate is 20 - 100 nm, and the purity > 99%.

[0010] Further, the flame retardant is an organophosphorus-based flame retardant, including any one or a combination of organophosphates, phosphates, phosphites, and phosphonates; the present invention preferably uses organophosphates, wherein the organophosphates include any one or a combination of disodium hexametaphthalate, trisodium hexametaphthalate, trisodium pentametaphthalate, and disodium tetrametaphthalate.

[0011] Further, the anti-aging agent includes any one or a combination of benzyl ketone anti-aging agents, aromatic aminophenol anti-aging agents, benzothiazole anti-aging agents, and polyphenol anti-aging agents; the present invention preferably uses polyphenol anti-aging agents, wherein the polyphenol anti-aging agents include 2,5-di-tert-butylhydroquinone and / or 4,4'-ethylidene bis(2,6-di-tert-butylphenol).

[0012] Further, the softening agent includes any one or a combination of petroleum-based softening agents, turpentine-based rubber softening agents, fatty oil-based rubber softening agents, and synthetic rubber softening agents; the present invention preferably uses turpentine-based rubber softening agents, wherein the turpentine-based rubber softening agents include any one or a combination of pine tar, rosin, and tall oil.

[0013] Further, the antistatic agent includes any one or a combination of antistatic agent SN, antistatic agent AVC, antistatic agent TM, and antistatic agent SP.

[0014] Further, the vulcanizing agent includes any one or a combination of sulfur, zinc oxide, magnesium oxide, lead oxide, lead tetraoxide, and resin.

[0015] Further, the vulcanization accelerator includes any one or a combination of vulcanization accelerator TMTD, vulcanization accelerator M, vulcanization accelerator D, and vulcanization accelerator NA-22.

[0016] Further, the preparation method of the modified silica includes:

[0017] S1. Prepare the first silica powder:

[0018] First, reflux the fumed silica powder in an ethanol solution to obtain pretreated fumed silica powder. Then, take γ-aminopropyltriethoxysilane and succinic anhydride respectively and add them into N,N-dimethylformamide. After stirring and mixing evenly at room temperature, stir and react at 70 - 80 °C for 3 - 5 h. Add the pretreated fumed silica powder, and at the same time, dropwise add distilled water, continue to keep warm and stir and react for 4 - 8 h. After the reaction is completed, cool to room temperature and filter to separate the powder particles. Wash them three times with ethanol and deionized water in sequence. After drying treatment, the first fumed silica powder is obtained.

[0019] S2. Prepare the second fumed silica powder:

[0020] Take the first fumed silica powder and mix it with N,N-dimethylformamide. Disperse it evenly under the action of ultrasonic waves. Then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinimide (NHS) in sequence. After stirring and reacting at 30 - 40 °C for 0.5 - 1 h, add styreneamine, continue to keep warm and stir and react for 8 - 16 h. Then filter out the powder particles. Wash them three times with ethanol and deionized water in sequence. After drying treatment, the second fumed silica powder is obtained.

[0021] S3. Prepare the modified fumed silica:

[0022] Add the second fumed silica powder and 2-mercaptopyrimidine into tetrahydrofuran. Disperse it evenly under the action of ultrasonic waves. Then add the catalyst benzoin dimethyl ether, stir fully at room temperature, and then stir and react under the irradiation of ultraviolet light. The reaction time is 10 - 20 min, and the stirring speed is 300 - 500 rpm. After the reaction is completed, filter out the powder particles. Wash them three times with ethanol and deionized water in sequence. After drying treatment, the modified fumed silica is obtained.

[0023] Furthermore, in the step S1, the model of the fumed silica powder is Wacker HDK H20.

[0024] Furthermore, in the step S1, the preparation process of the pretreated fumed silica powder specifically includes:

[0025] Mix the fumed silica powder in an ethanol solution, disperse it evenly under the action of ultrasonic waves, then reflux at 60 - 70 °C for 2 - 4 h, filter out the powder particles, and perform drying treatment to obtain the pretreated fumed silica powder.

[0026] Among them, the mass fraction of the ethanol solution is 50% - 60%, the average particle size of the fumed silica powder is 30 ± 5 nm, and the mass ratio of the fumed silica powder to the ethanol solution is 1:10 - 20.

[0027] Further, in the step S1, the mass ratio of the pretreated white carbon black powder, γ-aminopropyltriethoxysilane, succinic anhydride and N,N-dimethylformamide is 1:0.22-0.44:0.1-0.2:10-20; the dropping amount of distilled water is 10%-20% of the total mass of N,N-dimethylformamide.

[0028] Further, in the step S2, the mass ratio of p-aminostyrene, carbodiimide hydrochloride, N-hydroxysuccinimide and N,N-dimethylformamide is 1:0.24-0.36:0.2-0.3:10-20, and the mass ratio of the first white carbon black powder to p-aminostyrene is 1:0.2-0.4.

[0029] Further, in the step S3, the mass ratio of the second white carbon black powder, 2-mercaptopyrimidine and tetrahydrofuran is 1:0.17-0.34:10-20; the addition amount of the catalyst benzoin dimethyl ether is 0.5%-2.5% of the mass of the second white carbon black powder.

[0030] Further, in the step S3, the wavelength of the ultraviolet light is 254-345 nm and the power is 300 W.

[0031] In a second aspect, the present invention provides a method for preparing a flame-retardant and antistatic rubber V-belt, comprising:

[0032] (1) Weigh each component of the rubber V-belt according to the weight ratio, dry it to a constant weight in a vacuum drying oven, and reserve it for use;

[0033] (2) Mix styrene-butadiene rubber and nitrile rubber in an internal mixer, the internal mixing temperature is 60-80 °C, the internal mixing speed is 50-60 r / min, and the internal mixing time is 2-5 min;

[0034] (3) Then, sequentially add ultrafine calcium carbonate and modified white carbon black into the internal mixer in step (2), raise the temperature to 80-100 °C, the internal mixing speed is 50-60 r / min, and internally mix for 2-3 min;

[0035] (4) Add a softening agent, an antioxidant and an antistatic agent into the internal mixer in step (3) in sequence, keep the temperature and speed, continue to internally mix for 3-6 min, and then discharge the rubber to obtain an internally mixed raw rubber material, and the discharging temperature is 150 °C;

[0036] (5) After the internally mixed raw rubber material obtained in step (4) is parked for 4-8 h, it is re-added into the internal mixer, the internal mixing temperature is 60-80 °C, the internal mixing speed is 20-30 r / min, and a vulcanizing agent and a vulcanization accelerator are sequentially added, and the internal mixing time is 2-3 min;

[0037] (6) Calender the rubber compound obtained in step (5) to form a belt blank, place it in a vulcanization device, and conduct vulcanization treatment under the conditions of 150-160 °C and 8-12 MPa. The vulcanization time is 10-15 min, and finally the flame-retardant and antistatic rubber V-belt is obtained.

[0038] The beneficial effects of the present invention are as follows:

[0039] 1. The present invention prepares a rubber V-belt. The base rubber used is a composite of styrene-butadiene rubber and nitrile rubber. The added filler materials include ultrafine calcium carbonate and modified silica. In addition, additives such as flame retardants and antistatic agents are also added. Compared with traditional rubber materials, the modified silica added in the present invention is prepared by surface chemical cross-linking modification of silica. The groups such as pyrimidine, thioether, and amide bonds rich in its cross-linking structure not only increase the flame retardancy and antistatic property of the composite rubber, but also improve the mechanical properties and other basic properties.

[0040] 2. The processing performance of styrene-butadiene rubber is close to that of natural rubber, with good wear resistance, heat resistance, aging resistance, and vulcanization speed. Nitrile rubber has high oil resistance, good wear resistance and airtightness. The combined use of nitrile rubber and styrene-butadiene rubber can theoretically superimpose the advantages of both. However, due to the insufficient compatibility between nitrile rubber and styrene-butadiene rubber, the performance improvement is limited. And the modified silica added in the present invention, due to having various cross-linking groups such as pyrimidine, thioether, and amide bonds, can better improve the performance of the composite rubber.

[0041] 3. The modified silica prepared in the present invention is first treated with an amino coupling agent (γ-aminopropyltriethoxysilane) and a dianhydride (succinic anhydride) on silica powder to obtain carboxylated silica powder (the first silica powder); then under the action of EDC·HCl and NHS, the first silica powder is subjected to amidation binding with p-aminostyrene to obtain the second silica powder containing an amide group; then 2-mercaptopyrimidine and the second silica powder undergo a thiol-ene click reaction under the initiation of ultraviolet light, and finally the modified silica containing pyrimidine, thioether, and amide bonds is prepared.

[0042] 4. In the preparation process of the first silica powder, first activate the silica powder in ethanol to enhance the activity of its surface hydroxyl groups to obtain pretreated silica powder; then react γ-aminopropyltriethoxysilane with succinic anhydride to form triethoxysilane containing a carboxyl group. After the hydrolysis of triethoxysilane, silane containing both an amino group and a siloxane bond is obtained. The siloxane bond condenses with the surface hydroxyl groups of the pretreated silica powder, and finally carboxylated silica powder (the first silica powder) is obtained. Specific embodiments

[0043] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0044] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0045] The present invention will be further described below in conjunction with the following examples. Example 1

[0046] A flame retardant and antistatic rubber V-belt, calculated by weight, comprising:

[0047] 70 parts of nitrile rubber, 40 parts of styrene-butadiene rubber, 35 parts of ultrafine calcium carbonate, 24 parts of modified white carbon black, 20 parts of flame retardant, 12 parts of softener, 8 parts of antioxidant, 2.5 parts of antistatic agent, 6 parts of vulcanizing agent and 2 parts of vulcanization accelerator.

[0048] Among them, the brand of nitrile rubber is NBR1704; the brand of styrene-butadiene rubber is SBR1502; the particle size of ultrafine calcium carbonate is 20-100nm, and the purity is >99%; the flame retardant is disodium hexamethylenephthalate; the antioxidant is 2,5-di-tert-butylhydroquinone; the softener is refined tall oil DTO-30; the antistatic agent is antistatic agent SN; the vulcanizing agent is sulfur; and the vulcanization accelerator is vulcanization accelerator TMTD.

[0049] Wherein, the preparation method of modified white carbon black comprises:

[0050] S1, preparing the first white carbon black powder:

[0051] The silica powder is mixed in an ethanol solution, dispersed evenly under the action of ultrasound, and then refluxed at 65°C for 3 hours, the powder particles are filtered out, and dried to obtain pretreated silica powder; wherein the mass fraction of the ethanol solution is 55%, the silica powder model is Wacker HDK H20, the average particle size is 30±5nm, and the mass ratio of silica powder to ethanol solution is 1:15.

[0052] Take γ-aminopropyltriethoxysilane and succinic anhydride respectively and add them to N,N-dimethylformamide. After stirring and mixing evenly at room temperature, stir and react at 75°C for 4 hours, add pretreated silica powder, and add distilled water at the same time. Continue to keep warm and stir and react for 6 hours. After the reaction is completed, cool to room temperature and filter to separate the powder particles. Wash them three times with ethanol and deionized water in turn, and obtain the first silica powder after drying. The mass ratio of pretreated silica powder, γ-aminopropyltriethoxysilane, succinic anhydride and N,N-dimethylformamide is 1:0.33:0.1:15; the amount of distilled water added is 15% of the total mass of N,N-dimethylformamide.

[0053] S2, preparing the second white carbon black powder:

[0054] The first white carbon black powder is mixed with N,N-dimethylformamide, and dispersed evenly under the action of ultrasound, and then carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinimide (NHS) are added in sequence, and the mixture is stirred and reacted at 35°C for 0.5h, and then p-aminostyrene is added, and the mixture is kept warm and stirred for 12h, and then the powder particles are filtered out, and washed three times with ethanol and deionized water in sequence, and dried to obtain the second white carbon black powder; wherein the mass ratio of p-aminostyrene, carbodiimide hydrochloride, N-hydroxysuccinimide and N,N-dimethylformamide is 1:0.3:0.2:10, and the mass ratio of the first white carbon black powder to p-aminostyrene is 1:0.3.

[0055] S3, preparation of modified white carbon black:

[0056] The second silica powder and 2-mercaptopyrimidine are added to tetrahydrofuran, dispersed evenly under the action of ultrasound, and then the catalyst benzoin dimethyl ether is added, fully stirred at room temperature, and then stirred to react under ultraviolet light. The reaction time is 15 minutes and the stirring speed is 400rpm. After the reaction is completed, the powder particles are filtered out, washed three times with ethanol and deionized water in sequence, and dried to obtain modified silica; wherein the wavelength of the ultraviolet light is 345nm and the power is 300W; the mass ratio of the second silica powder, 2-mercaptopyrimidine and tetrahydrofuran is 1:0.26:20; the amount of the catalyst benzoin dimethyl ether added is 1.5% of the mass of the second silica powder.

[0057] The method for preparing the flame retardant antistatic rubber V-belt comprises:

[0058] (1) Weigh the components of the rubber V-belt according to the weight ratio, dry them in a vacuum drying oven to constant weight, and set aside;

[0059] (2) Mix styrene-butadiene rubber and nitrile rubber in an internal mixer at a mixing temperature of 70°C, a mixing speed of 55 r / min, and a mixing time of 3 min;

[0060] (3) Then, the ultrafine calcium carbonate and modified white carbon black are added into the internal mixer of step (2) in sequence, the temperature is raised to 100° C., the internal mixing speed is 50 r / min, and the internal mixing is performed for 3 minutes;

[0061] (4) Add the softener, antioxidant and antistatic agent into the internal mixer of step (3) in sequence, maintain the temperature and speed, continue internal mixing for 4 minutes, and then discharge the rubber to obtain the internal mixing raw rubber material, and the discharge temperature is 150°C;

[0062] (5) After the mixed raw rubber material obtained in step (4) is left for 6 hours, it is added back into the internal mixer at a mixing temperature of 70°C and a mixing speed of 30 r / min. The vulcanizing agent and the vulcanization accelerator are added in sequence. The mixing time is 2 minutes.

[0063] (6) The rubber compound obtained in step (5) is calendered to form a belt blank, which is placed in a vulcanization device and vulcanized at 160° C. and 10 MPa for 12 min to finally obtain the flame retardant and antistatic rubber V-belt. Example 2

[0064] A flame retardant and antistatic rubber V-belt, calculated by weight, comprising:

[0065] 60 parts of nitrile rubber, 30 parts of styrene-butadiene rubber, 25 parts of ultrafine calcium carbonate, 16 parts of modified white carbon black, 14 parts of flame retardant, 10 parts of softener, 6 parts of antioxidant, 1.5 parts of antistatic agent, 3 parts of vulcanizing agent and 1 part of vulcanization accelerator.

[0066] Among them, the brand of nitrile rubber is NBR2707; the brand of styrene-butadiene rubber is SBR1500. The particle size of ultrafine calcium carbonate is 20-100nm, and the purity is >99%. The flame retardant is trisodium hexamethylene phthalate. The antioxidant is 4,4'-ethylenebis(2,6-di-tert-butylphenol). The softener is pine tar No. 1. The antistatic agent is antistatic agent AVC. The vulcanizer is zinc oxide. The vulcanization accelerator is vulcanization accelerator M.

[0067] Wherein, the preparation method of modified white carbon black comprises:

[0068] S1. Preparation of first white carbon black powder:

[0069] Mix the fumed silica powder in an ethanol solution, disperse it evenly under the action of ultrasonic waves, then reflux it at 60 °C for 2 h, filter out the powder particles, and perform a drying treatment to obtain the pretreated fumed silica powder; among them, the mass fraction of the ethanol solution is 50%, the model of the fumed silica powder is Wacker HDK H20, the average particle size is 30 ± 5 nm, and the mass ratio of the fumed silica powder to the ethanol solution is 1:10.

[0070] Respectively take γ-aminopropyltriethoxysilane and succinic anhydride and add them to N,N-dimethylformamide. After stirring and mixing evenly at room temperature, stir and react at 70 °C for 3 h, add the pretreated fumed silica powder, and at the same time dropwise add distilled water, and continue to stir and react while keeping warm for 4 h. After the reaction is completed, cool to room temperature and filter to separate the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the first fumed silica powder is obtained; among them, the mass ratio of the pretreated fumed silica powder, γ-aminopropyltriethoxysilane, succinic anhydride and N,N-dimethylformamide is 1:0.22:0.1:10; the dropping amount of distilled water is 10% of the total mass of N,N-dimethylformamide.

[0071] S2. Prepare the second fumed silica powder:

[0072] Take the first fumed silica powder and mix it with N,N-dimethylformamide, disperse it evenly under the action of ultrasonic waves, then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinimide (NHS) in sequence, stir and react at 30 °C for 0.5 h, add p-aminostyrene, continue to stir and react while keeping warm for 8 h, then filter out the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the second fumed silica powder is obtained; among them, the mass ratio of p-aminostyrene, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and N,N-dimethylformamide is 1:0.24:0.2:10, and the mass ratio of the first fumed silica powder to p-aminostyrene is 1:0.2.

[0073] S3. Prepare the modified fumed silica:

[0074] Add the second fumed silica powder and 2-mercaptopyrimidine to tetrahydrofuran, disperse it evenly under the action of ultrasonic waves, then add the catalyst benzoin dimethyl ether, stir well at room temperature, and then stir and react under the irradiation of ultraviolet light. The reaction time is 10 min, the stirring speed is 300 rpm. After the reaction is completed, filter out the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the modified fumed silica is obtained; among them, the wavelength of the ultraviolet light is 254 nm and the power is 300 W; the mass ratio of the second fumed silica powder, 2-mercaptopyrimidine and tetrahydrofuran is 1:0.17:10; the addition amount of the catalyst benzoin dimethyl ether is 0.5% of the mass of the second fumed silica powder.

[0075] The preparation method of the above flame-retardant and antistatic rubber V-belt includes:

[0076] (1) Weigh each component of the rubber V-belt according to the weight parts ratio, dry it to constant weight in a vacuum drying oven, and reserve it for use;

[0077] (2) Mix styrene-butadiene rubber and nitrile rubber in an internal mixer. The internal mixing temperature is 60 °C, the internal mixing speed is 50 r / min, and the internal mixing time is 2 min;

[0078] (3) Then, add ultrafine calcium carbonate and modified silica white to the internal mixer in step (2) in sequence, raise the temperature to 80 °C, keep the internal mixing speed at 50 r / min, and internally mix for 2 min;

[0079] (4) Add softening agent, antioxidant, and antistatic agent to the internal mixer in step (3) in sequence, keep the temperature and speed, continue to internally mix for 3 min, and then discharge the rubber to obtain the internally mixed raw rubber material. The discharging temperature is 150 °C;

[0080] (5) After the internally mixed raw rubber material obtained in step (4) is parked for 4 h, re-add it to the internal mixer. The internal mixing temperature is 60 °C, the internal mixing speed is 20 r / min, add vulcanizing agent and vulcanization accelerator in sequence, and the internal mixing time is 2 min;

[0081] (6) Calender the rubber material obtained in step (5) to make a belt blank, place it in a vulcanization device, and vulcanize it under the conditions of 150 °C and 8 MPa. The vulcanization time is 10 min, and finally obtain the above flame-retardant and antistatic rubber V-belt. Example 3

[0082] A flame-retardant and antistatic rubber V-belt, calculated by weight parts, includes:

[0083] 80 parts of nitrile rubber, 50 parts of styrene-butadiene rubber, 45 parts of ultrafine calcium carbonate, 32 parts of modified silica white, 28 parts of flame retardant, 15 parts of softening agent, 12 parts of antioxidant, 3.5 parts of antistatic agent, 8 parts of vulcanizing agent, and 3 parts of vulcanization accelerator.

[0084] Among them, the grade of nitrile rubber is NBR2907; the grade of styrene-butadiene rubber is SBR1712. The particle size of ultrafine calcium carbonate is 20 - 100 nm, and the purity > 99%. The flame retardant is trisodium pentaphenylenedicarboxylate. The antioxidant is 2,5-di-tert-butylhydroquinone. The softening agent is rosin. The antistatic agent is antistatic agent SP. The vulcanizing agent is sulfur. The vulcanization accelerator is vulcanization accelerator NA-22.

[0085] The preparation method of modified silica white includes:

[0086] S1. Prepare the first silica white powder:

[0087] Mix the fumed silica powder in an ethanol solution, disperse it evenly under the action of ultrasonic waves, then reflux at 70 °C for 4 h, filter out the powder particles, and perform a drying treatment to obtain the pretreated fumed silica powder; among them, the mass fraction of the ethanol solution is 60%, the model of the fumed silica powder is Wacker HDK H20, the average particle size is 30 ± 5 nm, and the mass ratio of the fumed silica powder to the ethanol solution is 1:20.

[0088] Respectively take γ-aminopropyltriethoxysilane and succinic anhydride and add them to N,N-dimethylformamide. After stirring and mixing evenly at room temperature, stir and react at 80 °C for 5 h. Add the pretreated fumed silica powder, and at the same time dropwise add distilled water, and continue to stir and react while keeping warm for 8 h. After the reaction is completed, cool to room temperature and filter to separate out the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the first fumed silica powder is obtained; among them, the mass ratio of the pretreated fumed silica powder, γ-aminopropyltriethoxysilane, succinic anhydride and N,N-dimethylformamide is 1:0.44:0.2:20; the dropping amount of distilled water is 20% of the total mass of N,N-dimethylformamide.

[0089] S2. Prepare the second fumed silica powder:

[0090] Take the first fumed silica powder and mix it with N,N-dimethylformamide, disperse it evenly under the action of ultrasonic waves, then add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and N-hydroxysuccinimide (NHS) in sequence, stir and react at 40 °C for 1 h, add p-aminostyrene, and continue to stir and react while keeping warm for 16 h. Then filter out the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the second fumed silica powder is obtained; among them, the mass ratio of p-aminostyrene, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and N,N-dimethylformamide is 1:0.36:0.3:20, and the mass ratio of the first fumed silica powder to p-aminostyrene is 1:0.4.

[0091] S3. Prepare the modified fumed silica:

[0092] Add the second fumed silica powder and 2-mercaptopyrimidine to tetrahydrofuran, disperse it evenly under the action of ultrasonic waves, then add the catalyst benzoin dimethyl ether, stir well at room temperature, and then stir and react under the irradiation of ultraviolet light. The reaction time is 20 min, and the stirring speed is 500 rpm. After the reaction is completed, filter out the powder particles, and wash them three times with ethanol and deionized water in sequence. After drying treatment, the modified fumed silica is obtained; among them, the wavelength of the ultraviolet light is 345 nm and the power is 300 W; the mass ratio of the second fumed silica powder, 2-mercaptopyrimidine and tetrahydrofuran is 1:0.34:20; the addition amount of the catalyst benzoin dimethyl ether is 2.5% of the mass of the second fumed silica powder.

[0093] The preparation method of the above flame-retardant and antistatic rubber V-belt includes:

[0094] (1) Weigh each component of the rubber V-belt according to the weight parts ratio, dry it to constant weight in a vacuum drying oven, and reserve it for use;

[0095] (2) Mix styrene-butadiene rubber and nitrile rubber in an internal mixer, with the internal mixing temperature being 80°C, the internal mixing speed being 60 r / min, and the internal mixing time being 5 min;

[0096] (3) Then, add ultrafine calcium carbonate and modified silica white to the internal mixer in step (2) in sequence, raise the temperature to 100°C, keep the internal mixing speed at 60 r / min, and internally mix for 3 min;

[0097] (4) Add softener, antioxidant, and antistatic agent to the internal mixer in step (3) in sequence, keep the temperature and speed, continue to internally mix for 3 - 6 min, and then discharge the rubber to obtain the internally mixed raw rubber material, with the discharge temperature being 150°C;

[0098] (5) After parking the internally mixed raw rubber material obtained in step (4) for 8 h, re-add it to the internal mixer, with the internal mixing temperature being 80°C and the internal mixing speed being 30 r / min. Add vulcanizing agent and vulcanization accelerator in sequence, and the internal mixing time is 3 min;

[0099] (6) Calender the rubber material obtained in step (5) to make a belt blank, place it in a vulcanization device, and vulcanize it under the conditions of 160°C and 12 MPa for 15 min to finally obtain the flame-retardant and antistatic rubber V-belt.

[0100] Comparative Example 1

[0101] A rubber V-belt, which is different from Example 1 in that the modified silica white in the components is replaced with silica white, and the other components are the same as those in Example 1. The preparation process of the rubber V-belt is the same as that in Example 1; that is, the components of the rubber V-belt are calculated by weight parts and include:

[0102] 70 parts of nitrile rubber, 40 parts of styrene-butadiene rubber, 35 parts of ultrafine calcium carbonate, 24 parts of silica white, 20 parts of flame retardant, 12 parts of softener, 8 parts of antioxidant, 2.5 parts of antistatic agent, 6 parts of vulcanizing agent, and 2 parts of vulcanization accelerator.

[0103] Among them, the silica white powder has a model of N375 and an average particle size of 30 ± 5 nm.

[0104] Comparative Example 2

[0105] A rubber V-belt, which differs from Example 1 in that the modified silica in the composition is replaced by the first silica powder prepared in Example 1, and the remaining components are the same as those in Example 1. The preparation process of the rubber V-belt is the same as that in Example 1; that is, the components of the rubber V-belt are calculated by weight and include:

[0106] 70 parts of nitrile rubber, 40 parts of styrene-butadiene rubber, 35 parts of ultrafine calcium carbonate, 24 parts of first white carbon black powder, 20 parts of flame retardant, 12 parts of softener, 8 parts of antioxidant, 2.5 parts of antistatic agent, 6 parts of vulcanizing agent and 2 parts of vulcanization accelerator.

[0107] The preparation method of the first white carbon black powder is the same as that in Example 1, see step S1 of Example 1 for details.

[0108] Comparative Example 3

[0109] A rubber V-belt, which differs from Example 1 in that the modified silica in the composition is replaced by the second silica powder prepared in Example 1, and the remaining components are the same as those in Example 1. The preparation process of the rubber V-belt is the same as that in Example 1; that is, the components of the rubber V-belt are calculated by weight and include:

[0110] 70 parts of nitrile rubber, 40 parts of styrene-butadiene rubber, 35 parts of ultrafine calcium carbonate, 24 parts of second white carbon black powder, 20 parts of flame retardant, 12 parts of softener, 8 parts of antioxidant, 2.5 parts of antistatic agent, 6 parts of vulcanizing agent and 2 parts of vulcanization accelerator.

[0111] The preparation method of the second white carbon black powder is the same as that in Example 1, see steps S1 and S2 of Example 1 for details.

[0112] Experimental example

[0113] The rubber V-belt materials prepared in Example 1 and Comparative Examples 1-3 were tested for performance, including tensile strength (reference GB / T528), elongation at break (reference GB / T528), Shore A hardness (reference GB / T531.1), limiting oxygen index (reference GB / T2406.2), surface resistivity (reference GB / T1410) and aging treatment (GB / T3512, 150°C, 72h). The test results are shown in Table 1 below:

[0114]

[0115] It can be concluded from the experimental data in Table 1 that, compared with Comparative Examples 1-3, the rubber V-belt material prepared in Example 1 of the present invention has better tensile strength and elongation at break, indicating that it has higher strength and toughness; higher hardness, indicating better wear resistance; the limiting oxygen index reaches 31.8%, indicating strong flame retardancy; in addition, the surface resistivity value is smaller, indicating better antistatic performance; the retention rates of tensile strength and elongation at break after aging treatment are more balanced, indicating better aging resistance. In summary, it shows that the rubber V-belt material prepared in Example 1 of the present invention has stronger performance in many aspects compared with the existing rubber V-belt materials.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0117] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A flame retardant and antistatic rubber V-belt, It is characterized in that Calculated by weight, including: 60-80 parts of nitrile rubber, 30-50 parts of styrene-butadiene rubber, 25-45 parts of ultrafine calcium carbonate, 16-32 parts of modified white carbon black, 14-28 parts of flame retardant, 10-15 parts of softener, 6-12 parts of antioxidant, 1.5-3.5 parts of antistatic agent, 3-8 parts of vulcanizing agent and 1-3 parts of vulcanization accelerator; The preparation method of the modified white carbon black comprises: S1. Preparation of first white carbon black powder: First, the white carbon black powder is refluxed in an ethanol solution to obtain a pretreated white carbon black powder; then, γ-aminopropyltriethoxysilane and succinic anhydride are respectively added to N,N-dimethylformamide, stirred and mixed evenly at room temperature, stirred and reacted at 70-80° C. for 3-5 hours, the pretreated white carbon black powder is added, and distilled water is added dropwise, and the mixture is kept warm and stirred for 4-8 hours. After the reaction is completed, the mixture is cooled to room temperature and the powder particles are separated by filtration, and washed three times with ethanol and deionized water in sequence, and dried to obtain the first white carbon black powder; S2, preparing the second white carbon black powder: The first white carbon black powder is mixed with N,N-dimethylformamide, and dispersed evenly under the action of ultrasound, and then carbodiimide hydrochloride and N-hydroxysuccinimide are added in sequence, and stirred at 30-40° C. for 0.5-1 h, and then p-aminostyrene is added, and the mixture is stirred and reacted for 8-16 h. Then, the powder particles are filtered out, and washed three times with ethanol and deionized water in sequence, and dried to obtain the second white carbon black powder; S3, preparation of modified white carbon black: The second silica powder and 2-mercaptopyrimidine are added to tetrahydrofuran, dispersed evenly under the action of ultrasound, and then the catalyst benzoin dimethyl ether is added, fully stirred at room temperature, and then stirred to react under ultraviolet light. The reaction time is 10-20 minutes and the stirring speed is 300-500rpm. After the reaction is completed, the powder particles are filtered out, washed three times with ethanol and deionized water in turn, and dried to obtain modified silica.

2. A flame retardant and antistatic rubber V-belt according to claim 1, It is characterized in that The brand of the nitrile rubber includes any one of NBR1704, NBR2707, NBR2907 and NBR3355; the brand of the styrene butadiene rubber includes any one of SBR1502, SBR1500 and SBR1712; the particle size of the ultrafine calcium carbonate is 20-100nm, and the purity is greater than 99%.

3. The flame retardant and antistatic rubber V-belt according to claim 1, It is characterized in that The flame retardant is an organic phosphorus flame retardant, including any one or more combinations of organic phosphates, phosphates, phosphites, and phosphonates.

4. The flame retardant and antistatic rubber V-belt according to claim 1, It is characterized in that The antioxidant includes any one or more combinations of phenylpropyl ketone antioxidants, aromatic aminophenol antioxidants, benzothiazole antioxidants, and polyphenol antioxidants.

5. The flame retardant and antistatic rubber V-belt according to claim 1, It is characterized in that The softener includes any one or a combination of petroleum-based softeners, terpene-based rubber softeners, fatty oil-based rubber softeners, and synthetic rubber softeners.

6. A flame-retardant and antistatic rubber V-belt according to claim 1, characterized in that the antistatic agent includes any one or a combination of antistatic agent SN, antistatic agent AVC, antistatic agent TM, and antistatic agent SP; the vulcanizing agent includes any one or a combination of sulfur, zinc oxide, magnesium oxide, lead oxide, lead tetraoxide, and resin; the vulcanization accelerator includes any one or a combination of vulcanization accelerator TMTD, vulcanization accelerator M, vulcanization accelerator D, and vulcanization accelerator NA-22.

7. A flame-retardant and antistatic rubber V-belt according to claim 1, characterized in that in the S1, the preparation process of the pretreated white carbon black powder specifically includes: Mix the white carbon black powder in an ethanol solution, disperse it evenly under the action of ultrasonic waves, then reflux at 60-70 °C for 2-4 h, filter out the powder particles, and perform a drying treatment to obtain the pretreated white carbon black powder; wherein, the mass fraction of the ethanol solution is 50%-60%, the average particle size of the white carbon black powder is 30±5 nm, and the mass ratio of the white carbon black powder to the ethanol solution is 1:10-20.

8. A flame-retardant and antistatic rubber V-belt according to claim 1, characterized in that in the S1, the mass ratio of the pretreated white carbon black powder, γ-aminopropyltriethoxysilane, succinic anhydride, and N,N-dimethylformamide is 1:0.22-0.44:0.1-0.2:10-20; the dropping amount of distilled water is 10%-20% of the total mass of N,N-dimethylformamide; in the S2, the mass ratio of p-aminostyrene, carbodiimide hydrochloride, N-hydroxysuccinimide, and N,N-dimethylformamide is 1:0.24-0.36:0.2-0.3:10-20, and the mass ratio of the first white carbon black powder to p-aminostyrene is 1:0.2-0.4; in the S3, the mass ratio of the second white carbon black powder, 2-mercaptopyrimidine, and tetrahydrofuran is 1:0.17-0.34:10-20; the addition amount of the catalyst benzoin dimethyl ether is 0.5%-2.5% of the mass of the second white carbon black powder, the wavelength of the ultraviolet light is 254-345 nm, and the power is 300 W.

9. A method for preparing a flame-retardant and antistatic rubber V-belt according to any one of claims 1-8, characterized in that it includes: (1) Weigh each component of the rubber V-belt according to the weight ratio, dry it to constant weight in a vacuum drying oven, and set aside; (2) Mix styrene-butadiene rubber and nitrile rubber in an internal mixer, the internal mixing temperature is 60-80 °C, the internal mixing speed is 50-60 r / min, and the internal mixing time is 2-5 min; (3) Then add ultrafine calcium carbonate and modified white carbon black to the internal mixer in step (2) in sequence, raise the temperature to 80-100 °C, the internal mixing speed is 50-60 r / min, and internally mix for 2-3 min; (4) Add softening agent, anti-aging agent, and antistatic agent into the internal mixer in step (3) in sequence, maintain the temperature and speed, continue internal mixing for 3 - 6 min, then discharge the rubber, and obtain the internally mixed raw rubber material. The discharge temperature is 150 °C; (5) After the internally mixed raw rubber material obtained in step (4) is parked for 4 - 8 h, add it back into the internal mixer. The internal mixing temperature is 60 - 80 °C, the internal mixing speed is 20 - 30 r / min, add vulcanizing agent and vulcanization accelerator in sequence, and the internal mixing time is 2 - 3 min; (6) Calender the rubber material obtained in step (5) to make a belt blank, place it in a vulcanizing device, and conduct vulcanization treatment under the conditions of 150 - 160 °C and 8 - 12 MPa. The vulcanization time is 10 - 15 min, and finally obtain the flame-retardant and antistatic rubber V-belt.

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