Lignin-based composition as well as preparation method and application thereof

Abstract

The invention relates to the field of rubber additives, in particular to a lignin-based composition as well as a preparation method and application thereof. Aiming at the problem of blockage caused by adhesion of a rubber component to a container and equipment when lignin is used as a reinforcing agent in the prior art, the lignin-based composition provided by the invention comprises lignin and a porous material, the mass ratio of the lignin to the porous material is 1: (0.12-0.5); the porous material comprises one or more of porous starch, a porous carbon material, porous calcium carbonate and porous kaolin; the porous carbon material comprises one or more of activated carbon, carbon black, mesoporous carbon, carbon nanotubes, graphene aerogel and biomass carbon. The preparation method comprises the following steps: drying lignin, and mixing the dried lignin with the dispersing agent and the porous material to obtain the lignin-based composition. By adding the lignin, the dispersing agent and the porous material in a specific proportion, electrostatic adsorption of the lignin is reduced, and the problem that the rubber composition is easy to adhere to a container and equipment is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rubber auxiliaries, in particular to a lignin-based composition and a preparation method and application thereof. BACKGROUND

[0002] The rubber industry relies heavily on carbon black and white carbon black (silica) as reinforcing fillers. Both of these materials are derived from non-renewable fossil fuels (carbon black from petroleum or coal tar) or high energy consumption processes (white carbon black). Lignin is a byproduct of the paper industry, which is abundant in resources, low in price and renewable. Using it in rubber can partially replace expensive carbon black / white carbon black, reduce formulation costs, and reduce dependence on fossil resources.

[0003] The lignin molecule structure contains a large number of phenolic hydroxyl groups and ether bonds and other functional groups, which endow it with some unique properties, such as: UV aging resistance, lignin can effectively absorb ultraviolet rays, prevent the rubber molecular chain from being broken by ultraviolet radiation, and significantly improve the weather resistance and service life of rubber products; antioxidant, the phenolic hydroxyl structure of lignin makes it a natural antioxidant that can capture free radicals that cause rubber aging and delay the thermal oxidation process. These properties are not possessed by traditional fillers.

[0004] As a natural organic polymer compound, lignin has broad application prospects, but the large number of polar hydroxyl groups on the surface of lignin cause lignin to easily agglomerate and form macroscopic defects. During the processing of rubber components as reinforcing agents, lignin is prone to adhere to containers and equipment, causing plugging problems. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the problem of rubber component adhesion to containers and equipment caused by lignin as a reinforcing agent in the prior art, thereby providing a lignin-based composition and a preparation method and application thereof.

[0006] To this end, the present application provides the following technical solutions: In a first aspect, the present application provides a lignin-based composition, comprising lignin and a porous material; the mass ratio of the lignin to the porous material is 1:(0.12-0.5), preferably 1:(0.12-0.4), more preferably 1:(0.12-0.3); The porous material includes one or more of porous starch, porous carbon material, porous calcium carbonate, and porous kaolin; The porous carbon material includes one or more of activated carbon, carbon black, mesoporous carbon, carbon nanotubes, graphene aerogel, and biomass carbon; Preferably, the porous carbon material is selected from one or more of carbon black and carbon nanotubes; The porous material is a solid material containing a large number of pores, which can be open (communicating) or closed (non-communicating), and the porosity of the porous material is 10%-90%; the pore size of the porous material significantly affects the performance of the material, such as adsorption capacity, permeability, etc.; the pore size of the porous material is 2nm-10um.

[0007] The porous starch is a new type of modified starch, which is obtained by modifying natural starch by physical, chemical or biological methods (such as enzymatic hydrolysis, acid treatment), and the pore structure mainly comes from the cavities and channels inside the starch granules; the porous starch can be used as a reinforcing filler for natural rubber or synthetic rubber, and its porous structure can increase the contact area inside the material, thereby possibly improving the mechanical properties of the rubber composite material; the porosity of the porous starch is 30%-60%, and the specific surface area is 1-10 m 2 / g.

[0008] The porous carbon material is a carbon-based material with rich pore structure, which can be prepared by activating, templating method, etc. from carbon precursors (such as resin, biomass, carbon black, etc.), and the pore structure is controllable and widely used (such as adsorption, energy storage, catalysis); the porosity of the porous carbon material is 40%-90%, and the specific surface area is 10-3000 m 2 / g.

[0009] The porous calcium carbonate is prepared by a special process (such as a template method, a bubble method), and belongs to a functional porous material. Generally, according to the difference of the preparation method (such as the porous structure formed by the assembly of nanoparticles), the porosity of the porous calcium carbonate is 50%-90%, and the specific surface area is 10-100 m 2 / g.

[0010] The porous kaolin is a material with a porous structure formed by calcining, acid treatment or composite modification of kaolin; the porosity of the porous kaolin is 30%-70%, and the specific surface area is 50-300 m 2 / g.

[0011] In an optional embodiment, the lignin is a commercially available lignin; Optionally, the lignin can be prepared by an alkali extraction process, a sulfite extraction process, an organic solvent extraction process, an enzymatic hydrolysis process, etc. Optionally, the particle size D50 of the lignin is less than 500um, and the ash content is less than 20%; preferably, the particle size D50 of the lignin is less than 150um, and the ash content is less than 15%; more preferably, the particle size D50 of the lignin is less than 50um, and the ash content is less than 5%.

[0012] In an alternative embodiment, the carbon black comprises one or more of a primary carbon black, a recycled carbon black, a regenerated carbon black.

[0013] In an alternative embodiment, the carbon black has a nitrogen adsorption specific surface area of 20-200 m 2 / g. Preferably, the carbon black has a nitrogen adsorption specific surface area of 30-180 m 2 / g.

[0014] In an alternative embodiment, the porous carbon nanotube has a nitrogen adsorption specific surface area of 100-1000 m 2 / g. Preferably, the porous carbon nanotube has a nitrogen adsorption specific surface area of 100-800 m 2 / g.

[0015] In an alternative embodiment, the lignin-based composition further comprises a dispersant. The dispersant is one or more of a fatty acid ester, including glycerol fatty acid ester, sorbitol fatty acid ester, polyglycerol fatty acid ester, zinc fatty acid soap.

[0016] In an alternative embodiment, the mass ratio of the lignin, the dispersant, and the porous material is 1: (0.025-0.1): (0.12-0.5), preferably 1: (0.025-0.1): (0.12-0.4), more preferably 1: (0.025-0.1): (0.12-0.3).

[0017] In a second aspect, the present application provides a method for preparing a lignin-based composition, comprising the following steps: S1. drying the lignin to control the water mass content to be ≤4%; S2. mixing the lignin with a porous material to obtain a lignin-based composition; In an alternative embodiment, the temperature for drying the lignin in S1 is 50-110°C. and / or, the temperature for mixing the lignin with the porous material in S2 is 40-80°C, the mixing speed is 50-1500 r / min, and the mixing time is 0.5-3 h. In a third aspect, the present application provides a method for preparing a lignin-based composition, comprising the following steps: S1'. drying the lignin to control the water mass content to be ≤4%; S2'. mixing the lignin with a dispersant to obtain a lignin premix; S3'. mixing the lignin premix with a porous material to obtain a lignin-based composition; In an optional embodiment, the lignin drying temperature in S1' is 50-110℃. In an optional embodiment, the temperature for mixing lignin and dispersant in S2' is 40-80℃, the mixing time is 0.5-3h, and the mixing speed is 50-1500r / min. Preferably, the mixing speed for mixing lignin and dispersant in S2' is 50-1000r / min, more preferably 50-800r / min.

[0018] In an optional embodiment, the temperature for mixing lignin and dispersant in S2' is 40-80℃, the mixing time is 0.5-3h, and the mixing speed is 50-1500r / min.

[0019] In a third aspect, the present application provides a rubber composition comprising the lignin-based composition or the lignin-based composition prepared according to the preparation method of the lignin-based composition.

[0020] In an optional embodiment, the rubber composition further comprises natural rubber, zinc oxide, stearic acid, sulfur, and an accelerator.

[0021] In an optional embodiment, the accelerator is 2,2'-dithiobisbenzothiazole.

[0022] In an optional embodiment, the mass ratio of the lignin-based composition, natural rubber, zinc oxide, and stearic acid is (45-55):100:(4-6):(2-4).

[0023] In a fourth aspect, the present application provides a preparation method of vulcanized rubber, comprising the following steps: Obtaining the rubber composition, and then vulcanizing the rubber composition to obtain the vulcanized rubber. In an optional embodiment, the method for obtaining the rubber composition comprises: Mixing natural rubber, the lignin-based composition, zinc oxide, and stearic acid to obtain a masterbatch, and then mixing the masterbatch with sulfur and an accelerator to obtain the rubber composition.

[0024] The technical scheme of the present application has the following advantages: 1. The present application provides a lignin-based composition comprising lignin and porous material; the mass ratio of the lignin and the porous material is 1:(0.12-0.5); the porous material comprises one or more of porous starch, porous carbon material, porous calcium carbonate, and porous kaolin; the porous carbon material comprises one or more of activated carbon, carbon black, mesoporous carbon, carbon nanotube, graphene aerogel, and biomass carbon.

[0025] The application can reduce the agglomeration of lignin in rubber and improve the dispersion performance of lignin in rubber by adding lignin and porous materials in specific proportions. The specific surface area of the porous material is relatively large, providing a large number of adsorption sites. The non-polar structures such as benzene rings and aliphatic chains in the lignin molecules are attracted to the hydrophobic regions on the surface of the porous material through van der Waals forces, and the adsorption effect is generated by the electrostatic attraction. At the same time, the flexible molecular chains of lignin are embedded in the micropores or rough structures on the surface of the porous material, enhancing the mechanical anchoring effect, resulting in enhanced adsorption of lignin and porous materials, reducing the electrostatic adsorption between lignin and natural rubber, and solving the problem of easy adhesion of rubber composition to containers and equipment.

[0026] 2. The lignin-based composition further comprises a dispersant; optionally, the dispersant is a fatty acid ester, including one or more of glycerol fatty acid ester, sorbitol fatty acid ester, polyglycerol fatty acid ester, and zinc fatty acid soap. The mass ratio of lignin, dispersant, and porous material is 1: (0.025-0.1): (0.12-0.5), preferably 1: (0.025-0.1): (0.12-0.4), and more preferably 1: (0.025-0.1): (0.12-0.3).

[0027] The application can reduce the electrostatic adsorption of lignin to natural rubber by adding lignin, dispersant, and porous material in specific proportions, thereby solving the problem of adhesion to containers and equipment. If the amount of dispersant and porous material added is too small, the rubber composition prepared will adhere to the container and equipment, causing blockage problems.

[0028] The structure of the dispersant has a strong affinity for the surface of lignin. The polar part (ester group) of the molecule will quickly adsorb to the polar surface of lignin. This adsorption reduces the energy of the lignin surface, making it easier to be wetted by the rubber matrix. At the same time, it shields the polar hydroxyl groups on the surface of lignin, reducing the opportunity for direct interaction between lignin particles through hydrogen bonds, acting as a spatial isolation effect to prevent lignin agglomeration.

[0029] Lignin is a polar material, and natural rubber is a non-polar material. When mixed together, they tend to agglomerate. By adding a dispersant and porous material, the electrostatic adsorption of lignin is reduced, preventing the agglomeration of the lignin-based composition and improving the compatibility of lignin with the rubber matrix, allowing lignin to be better dispersed in the rubber matrix. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0031] Figure 1 A photograph of the rubber composition prepared for Comparative Example 1; Figure 2 A photograph of the rubber composition prepared for Comparative Example 2; Figure 3 A photograph of the rubber composition prepared for Comparative Example 3; Figure 4 A photograph of the rubber composition prepared for Comparative Example 4; Figure 5 A photograph of the rubber composition prepared for Example 1; Figure 6 A photograph of the rubber composition prepared for Example 2; Figure 7 A photograph of the rubber composition prepared for Example 3; Figure 8 A photograph of the rubber composition prepared for Example 4; Figure 9 A photograph of the rubber composition prepared for Example 5; Figure 10 A photograph of the rubber composition prepared for Example 6; Figure 11 A photograph of the rubber composition prepared for Example 7. DETAILED DESCRIPTION In order to better further understand the present application, the following examples are provided, but the following examples do not constitute limitations on the content and protection scope of the present application, and any product which is the same or similar to the present application obtained by anyone under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0032] If the specific experimental steps or conditions are not specified in the examples, they are operated according to the conventional experimental steps or conditions in the art. If the reagents or instruments used are not specified by the manufacturer, they are conventional reagent products or instruments which can be obtained by purchase in the market.

[0033] The components and sources are as follows: Lignin, porous calcium carbonate, porous kaolin and carbon black are commercially available; Natural rubber, Beijing Chengsheng Trading Co., Ltd.; Carbon black, Cabot (China) Investment Co., Ltd. Fatty acid zinc soap, Huaji (China) Chemical Co., Ltd. Zinc oxide, Dalian Zinc Oxide Factory Stearic acid, Taike Browning (Zhangjiagang) Co., Ltd. Sulfur, Jinan Rui Platinum Chemical Co., Ltd. Accelerator 2, 2'-dithiodibenzothiazole, Qingdao Huaheng Auxiliary Co., Ltd.

[0034] The instruments, models and manufacturers used in the preparation method of the vulcanized rubber are as follows: 1.6L BR1600 internal mixer, product of Farrel Company, USA Open mill, product of Bihong Machinery (Shanghai) Co., Ltd. XLB-D 600x600 type flat vulcanizing machine, product of Zhejiang Huzhou Hongqiao Machinery Factory 3365 type tensile machine, product of Instron Company, USA Compression calorimeter, product of Elmer Company, USA

[0035] Embodiments 1 and 3-7 of the present application provide a preparation method of a lignin-based composition, comprising the following steps: S1'. Drying lignin at 50-110℃ to control the moisture mass content to ≤4%; S2'. Mixing the above dried lignin with fatty acid zinc soap at a mixing temperature of 40-80℃, and mixing in a low-speed mixer at a speed of 50-1500r / min for 0.5-3h to obtain a lignin premix; S3'. Mixing the lignin premix with a porous material at a mixing temperature of 40-80℃, and mixing in a low-speed mixer at a speed of 50-1500r / min for 0.5-3h to obtain a lignin-based composition (referred to as composition 1, composition 3-7, respectively).

[0036] Embodiments 2 and Comparative Examples 1-4 of the present application provide a preparation method of a lignin-based composition, comprising the following steps: S1'. Drying lignin at 50-110℃ to control the moisture mass content to ≤4%; S2'. Mixing the above dried lignin with a porous material at a mixing temperature of 40-80℃, and mixing in a low-speed mixer at a speed of 50-1500r / min for 0.5-3h to obtain a lignin-based composition (referred to as composition 2, composition 8-11, respectively).

[0037] The specific process parameters of Examples 1-7 and Comparative Examples 1-4 are shown in Table 1.

[0038] Table 1 Process parameters of lignin-based compositions

[0039] Figures 1-11 For the physical picture of the lignin composition after mixing in the container, it can be seen that the lignin composition in Comparative Example 1 has serious adhesion phenomenon, which is easy to cause serious plugging during the preparation of rubber. The lignin prepared in Comparative Example 2 and Comparative Example 4 also adheres to the container, and the adhesion phenomenon is better than that of Comparative Example 1, and at the same time, the uniformity of the composition particles is poor, and large particles produced by lignin agglomeration also appear, which causes adverse effects on the subsequent application of lignin as a reinforcing agent in rubber. Figures 5-11 It can be seen that the lignin compositions prepared in Examples 1-7 do not have a large amount of adhesion, which overcomes the problems of wall sticking, poor flow performance, plugging of pipelines and dust during the application of lignin. At the same time, the lignin compositions prepared in Examples 3 and 4 are uniformly adsorbed on the porous material to form small particles, which avoids the formation of large particles by lignin agglomeration, and the lignin compositions prepared have good flowability during transportation, transfer and feeding. The present application also provides a method for preparing vulcanized rubber, comprising: Using a 1.6 liter internal mixer, natural rubber, lignin composition, zinc oxide and stearic acid were mixed for 6 min to obtain a masterbatch; the masterbatch was stored for 24 h, and then mixed with sulfur and 2,2'-dithiobisbenzothiazole in the internal mixer for 3.5 min, and then sheeting was performed using an open mill for use, thereby obtaining a rubber composition (the amount of each raw material is shown in Table 2); the obtained rubber composition was vulcanized at 160°C for 30 min, thereby obtaining a vulcanized rubber.

[0040] Table 2 Formulation table of rubber composition (unit: mass parts)

[0041] The dispersion performance of the rubber compositions prepared in each example and comparative example was tested according to the standard GB / T 6030-2006.

[0042] X represents the dispersion level of the rubber composition, which is represented by an integer 1-10, and 10 represents the best dispersion state, while 1 represents the worst dispersion state.

[0043] Y represents the lump level, which is represented by a number 1-10, and 10 represents that there is no lump with a diameter ≥23um; and 1 represents that there is a large amount of lump with a diameter ≥23um.

[0044] The performance of the rubber composition was evaluated using the formulation shown in Table 2, and the test results are shown in Table 3.

[0045] Table 3 Test results of the performance of the rubber composition

[0046] Comparing Comparative Examples 1-4 with Examples 1-7, it can be seen that Examples 3 and 4, which use carbon black as the porous material, have better dispersibility and less agglomeration than Comparative Examples 1-4, Examples 1, 2, and 5-7. As can be seen from the dispersibility test data, Example 3 has the highest X and Y values, reaching levels 6 and 9, and its lignin composition has the best dispersibility in rubber.

[0047] Obviously, the above examples are merely illustrative and not limiting. Based on the above description, those skilled in the art can make other different forms of changes or variations. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A lignin-based composition, characterized in that, The lignin and the porous material; the mass ratio of the lignin to the porous material is 1:(0.12-0.5); The porous material comprises one or more of porous starch, porous carbon material, porous calcium carbonate, and porous kaolin; The porous carbon material comprises one or more of activated carbon, carbon black, mesoporous carbon, carbon nanotube, graphene aerogel, and biomass carbon.

2. The lignin-based composition of claim 1, wherein, The carbon black in the porous carbon material comprises one or more of primary carbon black, recycled carbon black, and regenerated carbon black.

3. The lignin-based composition of claim 1, wherein, The nitrogen adsorption specific surface area of the carbon black in the porous carbon material is 20-200 m 2 / g.

4. The lignin-based composition of claim 1, wherein, The dispersant comprises one or more of fatty acid esters, including glycerol fatty acid ester, sorbitol fatty acid ester, polyglycerol fatty acid ester, and zinc fatty acid soap.

5. The lignin-based composition according to claim 4, characterized in that, The mass ratio of the lignin, the dispersant, and the porous material is 1:(0.025-0.1):(0.12-0.5), preferably 1:(0.025-0.1):(0.12-0.4), and more preferably 1:(0.025-0.1):(0.12-0.3).

6. A method of producing the lignin-based composition according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1. Drying the lignin to control the moisture mass content to ≤4%; S2. Mixing the lignin with the porous material to obtain the lignin-based composition.

7. The method of producing a lignin-based composition according to claim 6, characterized in that, The drying temperature of the lignin in S1 is 50-110°C; And / or, the mixing temperature of the lignin with the porous material in S2 is 40-80°C, the mixing speed is 50-1500 r / min, and the mixing time is 0.5-3 h.

8. A method of producing the lignin-based composition of claim 4 or 5, characterized by, The method comprises the following steps: S1’. Drying the lignin to control the moisture mass content to ≤4%; S2’. Mixing the lignin with the dispersant to obtain a lignin premix; S3’. Mixing the lignin premix with the porous material to obtain the lignin-based composition.

9. The method of producing a lignin-based composition according to claim 8, characterized in that, The drying temperature of the lignin in S1’ is 50-110°C; And / or, the mixing temperature of the lignin with the dispersant in S2’ is 40-80°C, the mixing time is 0.5-3 h, and the mixing speed is 50-1500 r / min; And / or, the mixing temperature of the lignin premix with the porous material in S3’ is 40-80°C, the mixing speed is 50-1500 r / min, and the mixing time is 0.5-3 h.

10. A rubber composition characterized in that, The lignin-based composition prepared by the method for preparing the lignin-based composition according to any one of claims 1-5 or according to claim 6 or 8.

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