Hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber master batch as well as preparation method and application thereof

Abstract

The invention relates to a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber master batch as well as a preparation method and application thereof, and belongs to the technical field of biomass energy and chemical industry. The preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber master batch comprises the following steps: washing industrial lignin with acidic water to obtain filter residues, mixing the filter residues with a sodium hydroxide solution, and carrying out a heating reflux reaction to obtain lignin black liquor; polyethylene glycol is heated and melted, a catalyst and epoxy alkyl halide are added for a reaction, and halogenated alcohol is obtained; mixing the lignin black liquor and halogenated alcohol, and stirring for reaction to obtain hydroxylated lignin; mixing a silicate solution, a silicon dioxide dispersing aid, hydroxylated lignin and styrene-butadiene latex, and performing acid precipitation, aging, water washing, soaking and drying to obtain the water-based paint. Industrial lignin, silicate and styrene-butadiene latex are adopted as raw materials, the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber master batch with excellent mechanical properties is prepared, waste biological resources are developed and utilized, and the process is simple.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass energy chemical industry, and specifically relates to a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, a preparation method and an application thereof. Background Art

[0002] Lignin is an extremely abundant organic substance in nature, with a rich chemical structure, and has attracted much attention for its renewability. Among them, phenolic hydroxyl, as a key functional group of lignin, plays a decisive role in the physical and chemical properties of lignin, such as solubility and reactivity. The diversity and potential application value of lignin have made it shine brightly in many industrial and scientific research fields.

[0003] Lignin is known for its unique network structure and high carbon content of 50-60%. After careful modification, it can be efficiently compounded with silica, making it an ideal choice for enhancing rubber performance. Unfortunately, a large amount of lignin is currently only used as a simple combustion material to release heat, and its hidden value has not been fully explored and reasonably applied. This situation is not only a huge waste of this abundant resource, but also misses the key role that lignin may play in materials science and high value-added industries.

[0004] In the process of creating rubber composites, reinforcing fillers play a vital role. They are the core elements of shaping rubber performance. Among many fillers, carbon black and silica are the best choices in the industry due to their excellent performance. Carbon black reinforced rubber is known for its significant elastic modulus, which gives the material extraordinary wear resistance and tear resistance; in contrast, silica reinforced rubber is highly praised for its low rolling resistance coefficient, which provides the possibility of improving vehicle fuel efficiency and reducing tire wear, but requires expensive silane coupling agents for surface modification. In order to combine the unique advantages of lignin and silica, cheap lignin is used to modify the surface of silica to create lignin / silica composite fillers. In such a composite system, once the proportion of lignin or silica dominates, its unique performance advantages become more prominent. This innovative strategy opens a new chapter in promoting sustainable development and the application of environmentally friendly materials. However, the existing lignin / silica fillers have defects such as uneven composite and large particle size, poor compatibility with rubber matrix, and low mechanical properties of rubber composites. Summary of the invention

[0005] The first object of the present invention is to provide a method for preparing a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch to solve the technical problems of uneven composite of lignin / silicon dioxide filler and poor compatibility with rubber matrix.

[0006] The second object of the present invention is to provide a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch.

[0007] The third object of the present invention is to provide an application of a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch.

[0008] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0009] A method for preparing a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch comprises the following steps:

[0010] S1: washing industrial lignin with acidic water to obtain a filter residue, mixing the filter residue with a sodium hydroxide solution, and heating the mixture under reflux to obtain a lignin black liquor;

[0011] S2: After heating and melting polyethylene glycol, a catalyst and epoxyhaloalkyl are added to react to obtain a halohydrin;

[0012] S3: mixing lignin black liquor and halogenated alcohol, stirring and reacting to obtain hydroxylated lignin;

[0013] S4: Mix the silicate solution, silica dispersant, hydroxylated lignin and styrene-butadiene latex, precipitate with acid, age, soak with water and dry to obtain the product.

[0014] Furthermore, the mass ratio of the silicon dioxide dispersant to the silicate is 1-20:1; the mass ratio of the hydroxylated lignin to the silicate is 1:5-20; and the mass ratio of the silicate solution to the styrene-butadiene latex is 1:1-10.

[0015] Furthermore, the temperature of the heating reflux reaction in S1 is 20-40° C., and the time is 2-6 hours; the mass ratio of the sodium hydroxide to the lignin is 1:4-5; and the solid content of the lignin black liquor is 20-30%.

[0016] Furthermore, the heating temperature in S2 is 40-60° C., the reaction time is 1-3 hours; the molar ratio of the polyethylene glycol to the epoxyhaloalkane is 1:1-2; and the mass ratio of the polyethylene glycol to the catalyst is 100-200:1.

[0017] Furthermore, the reaction temperature in S3 is 70-90° C., the reaction time is 2-4 hours, the reaction pH is 11-13; the stirring speed is 200-1000 r / min; and the mass ratio of the lignin black liquor to the halogenated alcohol is 100:5-30.

[0018] Furthermore, the mass concentration of the silicate solution in S4 is 20-50%, the solid content of the styrene-butadiene latex is 10-30%, the aging time is 1-3 hours, and the water washing and soaking time is 6-12 hours.

[0019] Furthermore, the acid precipitation step in S3 is: first use ammonium chloride for the first acid precipitation, and then use hydrochloric acid for the second acid precipitation; the pH of the first acid precipitation is 9-10.5, the temperature is 30-50°C, and the time is 0.5-2h; the pH of the second acid precipitation is 3-5, the temperature is 40-60°C, and the time is 0.5-2h.

[0020] Furthermore, the industrial lignin is one or more of softwood lignin, hardwood lignin, and herbaceous lignin; the polyethylene glycol is one or more of polyethylene glycol 300, polyethylene glycol 600, polyethylene glycol 1000, and polyethylene glycol 2000; the catalyst is one or more of boron trifluoride etherate, aluminum oxide, zinc oxide, and potassium iodide; the silica dispersant is one or more of C1-C6 alcohols; and the epoxyhaloalkane is epichlorohydrin.

[0021] A hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch is prepared by adopting the preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch.

[0022] The invention discloses an application of a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch in the preparation of rubber.

[0023] Beneficial effects of the present invention:

[0024] The hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch of the invention adopts industrial lignin, silicate and styrene butadiene latex as raw materials to prepare the hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch with excellent mechanical properties, develops and utilizes waste biological resources, is environmentally friendly and has a simple process.

[0025] The present invention uses two-step acid precipitation, and silicate is converted into silicon dioxide in the solution when the pH is 9-10.5. Ammonium chloride is used to promote the growth of silicon dioxide crystal nuclei, which serves as the core silicon of hydroxylated lignin / silicon dioxide. When the pH reaches 3-5, hydroxylated lignin is precipitated and coated on the surface of silicon dioxide to form hydroxylated lignin / silicon dioxide. At the same time, π-π interaction and entanglement between molecular chains occur between the hydroxylated lignin and styrene-butadiene rubber.

[0026] The hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch of the present invention not only brings the performance advantages of lignin and silicon dioxide into the rubber at the same time, but also can effectively avoid the agglomeration of inorganic nanoparticles by adding hydroxylated lignin to composite and coat silicon dioxide, overcomes the shortcomings of poor dispersibility and difficulty in mixing of silicon dioxide, improves the compatibility between silicon dioxide and polymer, and further improves the physical and mechanical properties of the rubber.

[0027] The hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch of the present invention is prepared by mixing the hydroxylated lignin / silicon dioxide composite with styrene butadiene latex in liquid phase and coagulating and coprecipitating to obtain the rubber masterbatch, thereby improving the dispersion of fillers in the rubber polymer, improving the physical and mechanical properties of the styrene butadiene rubber masterbatch and thus increasing the quality of the product, and reducing dust pollution, and is suitable for industrial continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the experimental steps for hydroxylating lignin in Example 1;

[0029] Figure 2 This is a particle size distribution diagram of the hydroxylated lignin / silicon dioxide composite material suspension obtained before adding styrene-butadiene latex in Example 1;

[0030] Figure 3 This is a physical picture of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch in Example 1. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the embodiments of the present invention and the accompanying drawings.

[0032] The vulcanizing agent used is sulfur powder.

[0033] Example 1

[0034] The preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch of Example 1 is as follows:

[0035] S1: 100 g of hardwood lignin was washed with deionized water at pH 3 to obtain a filter residue, 20 g of the filter residue was mixed with 80 g of a 6.25% sodium hydroxide solution, and heated under reflux at 25° C. for 2 h to obtain lignin black liquor. The solid content of the lignin black liquor was 25%.

[0036] S2: Weigh 100 g of polyethylene glycol 300 (PEG300) in a three-necked flask, heat to 55°C to completely melt, drop 0.8 g of boron trifluoride etherate, add 30.84 g of epichlorohydrin and control the dropping speed to 3 rpm, react for 2 h to obtain chloropolyethylene glycol.

[0037] S3: Prepare 100g of lignin black liquor with a solid content of 25% in a three-necked flask, heat it to 80°C, pump in 10g of polyethylene glycol chloride and control the drop rate to 3rpm, add 1.2g of 50% sodium hydroxide solution when pumping 1 / 3 of the mass of polyethylene glycol chloride, and then pump the remaining 2 / 3 of the mass of polyethylene glycol chloride, keep the pH of the reaction system within the range of 11-13, place the stirring paddle and flask vertically, stir at a speed of 350r / min, and react for 3h to obtain a hydroxylated lignin solution.

[0038] S4: In a 40°C water bath, 40g of 5wt% hydroxylated lignin solution and 40g of 31.85wt% sodium silicate nonahydrate solution were mixed in 300g of aqueous solution, 60g of ethanol was added and stirred for 20min to obtain a hydroxylated lignin / silicon dioxide composite suspension, and then 200g of 20wt% styrene-butadiene latex was added and uniformly dispersed for 30min. First, 2mol / L ammonium chloride solution was uniformly added dropwise for the first acid precipitation to adjust the pH of the reaction solution to 10, so that the silicon dioxide was uniformly precipitated, and the reaction was maintained for 0.5h to complete the first acid precipitation. After reacting for 0.5 h, the reaction temperature was raised to 50°C, and 1 mol / L hydrochloric acid solution was uniformly added dropwise for a second acid precipitation to adjust the pH of the reaction solution to 3, thereby completing the coating of silica by hydroxylated lignin and the π-π interaction between styrene-butadiene rubber molecules and the entanglement between molecular chains. The reaction was stirred for 0.5 h, aged for 1 h, washed and soaked in water for 8 h, and repeatedly extruded and dried to obtain a hydroxylated lignin / silica composite modified styrene-butadiene rubber masterbatch.

[0039] The rubber of Example 1 includes the following raw materials: 44 g of hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizing agent, and 0.6 g of vulcanization accelerator.

[0040] The rubber mixing process is as follows:

[0041] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch is put into the internal mixer and mixed for 1 minute, then zinc oxide and stearic acid are added together and mixed for 2 minutes, carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3, the time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0042] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0043] Example 2

[0044] The preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch of Example 2 is as follows:

[0045] S1: 100 g of hardwood lignin was washed with deionized water at pH 3 to obtain a filter residue, 20 g of the filter residue was mixed with 80 g of a 6.25% sodium hydroxide solution, and heated under reflux at 25° C. for 2 h to obtain lignin black liquor. The solid content of the lignin black liquor was 25%.

[0046] S2: Weigh 100 g of PEG300 into a three-necked flask, heat to 55°C to completely melt, drop 0.8 g of boron trifluoride etherate, add 30.84 g of epichlorohydrin and control the dropping speed to 3 rpm, react for 2 h to obtain chloropolyethylene glycol.

[0047] S3: Prepare 100g of lignin black liquor with a solid content of 25% in a three-necked flask, heat it to 80°C, pump in 6g of polyethylene glycol chloride and control the drop rate to 3rpm, pump 1 / 3 to add 0.72g of 50% sodium hydroxide solution by mass, and then pump the remaining 2 / 3, keep the pH of the reaction system within the range of 11-13, place the stirring paddle and flask vertically, stir at a speed of 350r / min, and react for 3h to obtain a hydroxylated lignin solution.

[0048] S4: In a 40°C water bath, 40g of 5wt% hydroxylated lignin solution and 40g of 31.85wt% sodium silicate nonahydrate solution were mixed in 300g of aqueous solution, 60g of ethanol was added and stirred for 20min to obtain a hydroxylated lignin / silicon dioxide composite suspension, and then 200g of 20wt% styrene-butadiene latex was added and uniformly dispersed for 30min. First, 2mol / L ammonium chloride solution was uniformly added dropwise for the first acid precipitation to adjust the pH of the reaction solution to 10, so that the silicon dioxide was uniformly precipitated, and the reaction was maintained for 0.5h to complete the first acid precipitation. After reacting for 0.5 h, the reaction temperature was raised to 50°C, and 1 mol / L hydrochloric acid solution was uniformly added dropwise for a second acid precipitation to adjust the pH of the reaction solution to 3, thereby completing the coating of silica by hydroxylated lignin and the π-π interaction between styrene-butadiene rubber molecules and the entanglement between molecular chains. The reaction was stirred for 0.5 h, aged for 1 h, washed and soaked in water for 8 h, and repeatedly extruded and dried to obtain a hydroxylated lignin / silica composite modified styrene-butadiene rubber masterbatch.

[0049] The rubber of Example 2 includes the following raw materials: 44 g of hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizing agent, and 0.6 g of vulcanization accelerator.

[0050] The rubber mixing process is as follows:

[0051] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch is put into the internal mixer and mixed for 1 minute, then zinc oxide and stearic acid are added together and mixed for 2 minutes, carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3, the time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0052] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0053] Example 3

[0054] The preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch of Example 3 is as follows:

[0055] S1: 100 g of hardwood lignin was washed with deionized water at pH 3 to obtain a filter residue, 20 g of the filter residue was mixed with 80 g of a 6.25% sodium hydroxide solution, and heated under reflux at 25° C. for 2 h to obtain lignin black liquor. The solid content of the lignin black liquor was 25%.

[0056] S2: Weigh 100 g of polyethylene glycol 600 (PEG600) in a three-necked flask, heat to 55°C to completely melt, drop 0.8 g of boron trifluoride etherate, add 15.42 g of epichlorohydrin and control the dropping speed to 3 rpm, react for 2 h to obtain chloropolyethylene glycol.

[0057] S3: Prepare 100g of lignin black liquor with a solid content of 25% in a three-necked flask, heat it to 80°C, pump in 10g of polyethylene glycol chloride and control the drop rate to 3rpm, pump 1 / 3 to add 0.6g of 50% sodium hydroxide solution, then pump the remaining 2 / 3, keep the pH of the reaction system within the range of 11-13, place the stirring paddle and flask vertically, stir at a speed of 350r / min, and react for 3h to obtain a hydroxylated lignin solution.

[0058] S4: In a 40°C water bath, 40g of 5wt% hydroxylated lignin solution and 40g of 31.85wt% sodium silicate nonahydrate solution were mixed in 300g of aqueous solution, 60g of ethanol was added and stirred for 20min to obtain a hydroxylated lignin / silicon dioxide composite suspension, and then 200g of 20wt% styrene-butadiene latex was added and uniformly dispersed for 30min. First, 2mol / L ammonium chloride solution was uniformly added dropwise for the first acid precipitation to adjust the pH of the reaction solution to 10, so that the silicon dioxide was uniformly precipitated, and the reaction was maintained for 0.5h to complete the first acid precipitation. After reacting for 0.5 h, the reaction temperature was raised to 50°C, and 1 mol / L hydrochloric acid solution was uniformly added dropwise for a second acid precipitation to adjust the pH of the reaction solution to 3, thereby completing the coating of silica by hydroxylated lignin and the π-π interaction between styrene-butadiene rubber molecules and the entanglement between molecular chains. The reaction was stirred for 0.5 h, aged for 1 h, washed and soaked in water for 8 h, and repeatedly extruded and dried to obtain a hydroxylated lignin / silica composite modified styrene-butadiene rubber masterbatch.

[0059] The rubber of Example 3 includes the following raw materials: 44 g of hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizing agent, and 0.6 g of vulcanization accelerator.

[0060] The rubber mixing process is as follows:

[0061] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch is put into the internal mixer and mixed for 1 minute, then zinc oxide and stearic acid are added together and mixed for 2 minutes, carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3, the time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0062] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0063] Example 4

[0064] The preparation method of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch of Example 4 is as follows:

[0065] S1: 100 g of hardwood lignin was washed with deionized water at pH 3 to obtain a filter residue, 20 g of the filter residue was mixed with 80 g of a 6.25% sodium hydroxide solution, and heated under reflux at 25° C. for 2 h to obtain lignin black liquor. The solid content of the lignin black liquor was 25%.

[0066] S2: Weigh 100 g of polyethylene glycol 600 (PEG600) in a three-necked flask, heat to 55°C to completely melt, drop 0.8 g of boron trifluoride etherate, add 15.42 g of epichlorohydrin and control the dropping speed to 3 rpm, react for 2 h to obtain chloropolyethylene glycol.

[0067] S3: Prepare 100g of lignin black liquor with a solid content of 25% in a three-necked flask, heat it to 80°C, pump in 6g of polyethylene glycol chloride and control the drop rate to 3rpm, pump 1 / 3 to add 0.36g of 50% sodium hydroxide solution by mass, and then pump the remaining 2 / 3, keep the pH of the reaction system within the range of 11-13, place the stirring paddle and flask vertically, stir at a speed of 350r / min, and react for 3h to obtain a hydroxylated lignin solution.

[0068] S4: In a 40°C water bath, 40g of 5wt% hydroxylated lignin solution and 40g of 31.85wt% sodium silicate nonahydrate solution were mixed in 300g of aqueous solution, 60g of ethanol was added and stirred for 20min to obtain a hydroxylated lignin / silicon dioxide composite suspension, and then 200g of 20wt% styrene-butadiene latex was added and uniformly dispersed for 30min. First, 2mol / L ammonium chloride solution was uniformly added dropwise for the first acid precipitation to adjust the pH of the reaction solution to 10, so that the silicon dioxide was uniformly precipitated, and the reaction was maintained for 0.5h to complete the first acid precipitation. After reacting for 0.5 h, the reaction temperature was raised to 50°C, and 1 mol / L hydrochloric acid solution was uniformly added dropwise for a second acid precipitation to adjust the pH of the reaction solution to 3, thereby completing the coating of silica by hydroxylated lignin and the π-π interaction between styrene-butadiene rubber molecules and the entanglement between molecular chains. The reaction was stirred for 0.5 h, aged for 1 h, washed and soaked in water for 8 h, and repeatedly extruded and dried to obtain a hydroxylated lignin / silica composite modified styrene-butadiene rubber masterbatch.

[0069] The rubber of Example 4 includes the following raw materials: 44 g of hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizer, and 0.6 g of accelerator.

[0070] The rubber mixing process is as follows:

[0071] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch is put into the internal mixer and mixed for 1 minute, then zinc oxide and stearic acid are added together and mixed for 2 minutes, carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3, the time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0072] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0073] Comparative Example 1

[0074] Under 40℃ water bath condition, add 80g of 5wt% lignin black liquor to 300g aqueous solution, add 60g ethanol and stir for 20min, then add 200g of 20wt% styrene butadiene latex and disperse evenly for 30min, first use 2mol / L ammonium chloride solution to drip at a uniform speed for the first acid precipitation, make the pH of the reaction solution to 10, and keep the reaction for 0.5h to complete the first acid precipitation. After 0.5h of reaction, increase the reaction temperature to 50℃, then use 1mol / L hydrochloric acid solution to drip at a uniform speed for the second acid precipitation, make the pH of the reaction solution to 3, stir and react for 0.5h, age and react for 1h, wash and soak for 8h, squeeze and dry repeatedly to obtain lignin modified styrene butadiene rubber masterbatch.

[0075] The rubber of Comparative Example 1 includes the following raw materials: 44 g of lignin-modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizing agent, and 0.6 g of vulcanization accelerator.

[0076] The rubber mixing process is as follows:

[0077] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the lignin modified styrene butadiene rubber masterbatch is put into the internal mixer, mixed for 1 minute, then zinc oxide and stearic acid are added together, mixed for 2 minutes, and carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3. The time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0078] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0079] Comparative Example 2

[0080] Under 40℃ water bath condition, add 80g of 31.85wt% sodium silicate nonahydrate solution to 300g aqueous solution, add 60g ethanol and stir for 20min, then add 200g of 20wt% styrene butadiene latex and disperse evenly for 30min, first use 2mol / L ammonium chloride solution to drip at a uniform speed for the first acid precipitation, make the pH of the reaction solution to 10, and keep the reaction for 0.5h to complete the first acid precipitation. After 0.5h of reaction, increase the reaction temperature to 50℃, then use 1mol / L hydrochloric acid solution to drip at a uniform speed for the second acid precipitation, make the pH of the reaction solution to 3, stir the reaction for 0.5h, age the reaction for 1h, wash and soak for 8h, squeeze repeatedly, and dry to obtain silica modified styrene butadiene rubber masterbatch.

[0081] The rubber of Comparative Example 2 includes the following raw materials: 44 g of silica-modified styrene-butadiene rubber masterbatch, 16 g of carbon black, 0.4 g of stearic acid, 2 g of zinc oxide, 0.6 g of vulcanizing agent, and 0.6 g of vulcanization accelerator.

[0082] The rubber mixing process is as follows:

[0083] Internal mixing process: the initial mixing temperature is set to 60°C, the speed of the internal mixer is adjusted to 60r / min, the silica-modified styrene-butadiene rubber masterbatch is put into the internal mixer, mixed for 1 minute, then zinc oxide and stearic acid are added together, mixed for 2 minutes, and carbon black is added twice, the first carbon black addition mass is 2 / 3 of the total mass, and the second addition mass is the remaining 1 / 3. The time interval between the two carbon black additions is 2 minutes, and they are mixed for 2 minutes respectively to produce the rubber.

[0084] The process of training: adding vulcanizing agent and vulcanization accelerator DM, tapping the rubber twice, triangle packing three times, rolling and rolling three times, and then the rubber composite material is obtained.

[0085] The vulcanization time and mechanical property indexes of the rubbers of Examples 1-4 and Comparative Examples 1-2 are shown in Tables 1 and 2.

[0086] Table 1 Vulcanization time of rubber of Examples 1-4 and Comparative Examples 1-2

[0087]

[0088] Table 1 M H is the maximum torque, M L is the minimum torque, △M is M H With M L The difference between the two, Tc10 is the pre-vulcanization time, and Tc90 is the positive vulcanization time.

[0089] It can be seen from Table 1 that the vulcanization time Tc90 of the rubber in Example 1 is shorter than that in Example 2; compared with the vulcanization time of Comparative Example 1, it can be seen that the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch can significantly increase the vulcanization rate; Compared with Comparative Example 2, Example 1 has a shorter vulcanization time Tc90 than that in Example 2. H Compared with △M, it is significantly improved, indicating that the degree of cross-linking is increased, and a denser cross-linking network is formed between the hydroxylated lignin / silica composite modified styrene-butadiene rubber masterbatch and the rubber molecular chain; the reason is that the hydroxylated modified lignin reduces the polar group phenolic hydroxyl group in the lignin, reduces the adsorption of the vulcanization accelerator, and weakens the vulcanization delay phenomenon of the rubber.

[0090] Table 2 Mechanical properties of rubber of Examples 1-4 and Comparative Examples 1-2

[0091]

[0092] Comparing the mechanical properties in Table 2, compared with Example 2, as the degree of modification of lignin by polyethylene glycol increases, the tensile strength of the rubber increases, and the elongation at break increases. The reason is that the amount of polyethylene glycol grafted in the lignin increases, which enhances the ductility of the lignin, so the elongation at break of the rubber increases; the polyethylene glycol chain is entangled with the rubber molecular chain, which improves the tensile strength of the rubber; compared with Comparative Example 1, it can be clearly seen that the hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch can significantly improve the mechanical properties of the rubber; compared with Comparative Example 2, the hydroxylated lignin / silicon dioxide can well solve the self-aggregation phenomenon of silicon dioxide in styrene butadiene rubber, thereby improving the tensile strength and elongation at break of styrene butadiene rubber.

[0093] The present invention provides a method for preparing a hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch, which reduces the cost of reinforcing fillers for styrene butadiene rubber, reduces the utilization of petroleum resources, and solves the problems of efficient utilization of lignin and environmental pollution caused by lignin. The method adopts two-step acid precipitation to prepare a hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch. The hydroxylated lignin / silicon dioxide composite modified styrene butadiene rubber masterbatch prepared by the method has excellent tensile strength and elongation at break, and is more conducive to application and promotion.

[0094] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, characterized in that: The following steps are involved: S1: washing industrial lignin with acidic water to obtain a filter residue, mixing the filter residue with a sodium hydroxide solution, and heating the mixture under reflux to obtain a lignin black liquor; S2: After heating and melting polyethylene glycol, a catalyst and epoxyhaloalkyl are added to react to obtain a halohydrin; S3: mixing lignin black liquor and halogenated alcohol, stirring and reacting to obtain hydroxylated lignin solution; S4: Mix the silicate solution, silica dispersant, hydroxylated lignin and styrene-butadiene latex, precipitate with acid, age, soak with water and dry to obtain the product.

2. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The mass ratio of the silicon dioxide dispersant to the silicate is 1-20:1; the mass ratio of the hydroxylated lignin to the silicate is 1:5-20; and the mass ratio of the silicate solution to the styrene-butadiene latex is 1:1-10.

3. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The temperature of the heating reflux reaction in S1 is 20-40° C., and the time is 2-6 hours; the mass ratio of the sodium hydroxide to the filter residue is 1:4-5; and the solid content of the lignin black liquor is 20-30%.

4. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The heating temperature in S2 is 40-60° C., the reaction time is 1-3 hours; the molar ratio of the polyethylene glycol to the epoxyhaloalkyl is 1:1-2; and the mass ratio of the polyethylene glycol to the catalyst is 100-200:

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5. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The reaction temperature in S3 is 70-90° C., the reaction time is 2-4 hours, and the reaction pH is 11-13; the stirring speed is 200-1000 r / min; and the mass ratio of the lignin black liquor to the halogenated alcohol is 100:5-30.

6. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The mass concentration of the silicate solution in S4 is 20-50%, and the solid content of the styrene-butadiene latex is 10-30%; The aging time is 1 to 3 hours, and the water washing and soaking time is 6 to 12 hours.

7. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The acid precipitation steps in S3 are: first use ammonium chloride for the first acid precipitation, and then use hydrochloric acid for the second acid precipitation; the pH of the first acid precipitation is 9-10.5, the temperature is 30-50°C, and the time is 0.5-2h; the pH of the second acid precipitation is 3-5, the temperature is 40-60°C, and the time is 0.5-2h.

8. The method for preparing the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch according to claim 1, characterized in that: The industrial lignin is one or more of softwood lignin, hardwood lignin, and herbaceous lignin; the polyethylene glycol is one or more of polyethylene glycol 300, polyethylene glycol 600, polyethylene glycol 1000, and polyethylene glycol 2000; the catalyst is one or more of boron trifluoride etherate, aluminum oxide, zinc oxide, and potassium iodide; the silicon dioxide dispersant is one or more of C1-C6 alcohols; and the epoxyhaloalkane is epichlorohydrin.

9. A hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch, characterized in that: The hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch is prepared by the preparation method of claim 1.

10. Use of the hydroxylated lignin / silicon dioxide composite modified styrene-butadiene rubber masterbatch as claimed in claim 9 in the preparation of rubber.

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