Method for continuously preparing highly dispersed bamboo fiber ultra-nano micro powder
By rapidly introducing an online high-shear dispersion field after bamboo fiber nanoforming, hydrogen bond recombination is suppressed, solving the structural changes and agglomeration problems during bamboo fiber nanoforming. This achieves efficient and stable bamboo fiber dispersion, improving production efficiency and the performance of composite materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHOUKANG MEDICAL SCI & TECH (SHANDONG) CO LTD
- Filing Date
- 2026-04-22
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies for bamboo fiber nano-sizing suffer from problems such as fiber structure changes, rapid recombination, and agglomeration, making it difficult to achieve continuous and stable processing and high dispersibility. Furthermore, they are energy-intensive or rely on chemical additives.
By rapidly introducing an online high-shear dispersion field after bamboo fiber nanofiber is nanoscaled, the shear strength and concentration are controlled, hydrogen bond recombination is suppressed, and stable dispersion of the fiber in the flow state is achieved, avoiding intermediate storage and buffering, and constructing a closed transport path.
It significantly improves the dispersion uniformity and stability of bamboo fiber, reduces energy consumption, and enhances production efficiency and the reinforcing effect of composite materials.
Smart Images
Figure CN122279999A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bamboo fiber processing technology, and more specifically, to a continuous method for preparing highly dispersible bamboo fiber ultra-nano powder. Background Technology
[0002] Bamboo fiber, as a widely available and renewable natural polymer material, has advantages such as low density, high specific strength, and good biocompatibility, and has been widely used in composite materials, papermaking, functional fillers, and environmentally friendly materials. With the continuous improvement of material performance requirements, further refining bamboo fiber to the nanoscale to obtain higher specific surface area and better interfacial compatibility has become an important development direction.
[0003] In existing technologies, the ultrafine processing of bamboo fibers typically employs methods such as mechanical crushing, high-pressure homogenization, microfluidic treatment, or ball milling to gradually dissociate the fibers to the micrometer or even nanometer scale. Simultaneously, to improve production efficiency, some processes attempt to adopt continuous processing methods, connecting pretreatment, fiber dissociation, and crushing steps in series. However, in practical applications, the above methods still have the following problems: First, existing continuous processes are mostly simple series connections of processing units. Materials often have buffering, storage or dwelling processes between different processes, making it difficult to achieve truly continuous and stable processing. Moreover, fiber structure changes are prone to occur during dwelling processes. Secondly, after bamboo fibers are mechanically dissociated to the nanoscale, a large number of hydroxyl groups are exposed on their surface, significantly increasing the surface energy of the system. This allows the fibers to readily recombine through hydrogen bonding, forming secondary aggregate structures. Existing technologies typically improve dispersibility by extending the mechanical shearing time or adding dispersants, but these methods are either energy-intensive or rely on chemical additives, making it difficult to achieve stable high dispersibility under continuous conditions. Furthermore, existing technologies generally focus on optimizing pulverizing equipment or pulverizing intensity, but lack effective control over the structural changes of bamboo fibers during nano-sizing. They fail to design processes that address the characteristic of rapid reorganization of fibers under high surface energy conditions, resulting in difficulty in maintaining a stable dispersion state even when nanoscale sizes are obtained. In addition, there is usually a time interval between the nano-sizing process and the subsequent dispersion process in the existing process. During this time, the fibers may have re-aggregated to varying degrees, thereby reducing the dispersion performance and application effect of the final product.
[0004] Therefore, how to construct a processing path that can suppress hydrogen bond recombination in the instantaneous high-activity state of bamboo fiber nanofiber during continuous preparation, so as to achieve stable dispersion of the fiber at the moment of nanofiberization and maintain its dispersed state in subsequent processes, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0005] The purpose of this invention is to provide a continuous method for preparing highly dispersible bamboo fiber ultra-nano powder, so as to solve the problems mentioned in the background art.
[0006] A continuous method for preparing highly dispersible bamboo fiber ultra-nano powder includes the following steps: S1. Bamboo raw materials are pretreated by lignin removal and mechanically defiberized to obtain bamboo fiber pulp; S2. The bamboo fiber pulp is continuously fed to the nano-pulverization unit for high-intensity mechanical defiberization, so that the bamboo fiber is dissociated into nano-scale fiber units and forms an instantaneous dispersion system in a high surface energy state. S3. Within the time window before the hydrogen bond recombination of the nanoscale fiber units, the system obtained in step S2 is directly introduced into an online high-shear dispersion field within 0.1 to 10 seconds without intermediate storage. S4. In the online high-shear dispersion field, a continuous shearing action is applied to the nanoscale bamboo fiber to keep the fiber units in a separated state in the flow state, and the re-binding between fibers is suppressed by controlling the coupling relationship between shear intensity and system concentration. S5. A stable and dispersed bamboo fiber nano-dispersion system is output under continuous flow conditions, and highly dispersed bamboo fiber ultra-nano powder is obtained after drying.
[0007] Preferably, the time interval between step S2 and step S3 does not exceed 5 seconds.
[0008] Preferably, the time interval between step S2 and step S3 does not exceed 2 seconds.
[0009] Preferably, in step S2, the nano-pulverization increases the specific surface area of bamboo fiber to 5 to 50 times that of the original fiber.
[0010] Preferably, the shear rate in step S4 is 8000–30000 s. -1 Furthermore, the solid content of the system is controlled between 0.5% and 3%, and the two satisfy the following relationship: When the solid content increases, the shear rate is increased simultaneously to maintain the average spacing between fibers.
[0011] Preferably, the outlet of the nano-pulverization unit and the inlet of the online dispersion unit are directly connected by a short-distance closed conveying structure, with the connection path length not exceeding 2m.
[0012] Preferably, the system remains in a turbulent state throughout steps S3 to S5, with a Reynolds number greater than 4000.
[0013] Preferably, a nonionic dispersant with a mass fraction of 0.01% to 0.2% is added in step S3 or S4.
[0014] Preferably, the redispersible particle size D50 of the obtained bamboo fiber ultra-nano powder in water is 100-300 nm, and there is no obvious sedimentation within 24 hours.
[0015] Compared with the prior art, the advantages of this invention are: (1) After the bamboo fiber is nano-sized, the present invention rapidly introduces an online dispersion system into the fiber within a time window when the fiber is in a high surface energy state, so that the fiber is forcibly dispersed before hydrogen bond recombination occurs, effectively suppressing the secondary agglomeration phenomenon, thereby significantly improving the dispersion uniformity of bamboo fiber.
[0016] (2) The present invention couples nano-pulverization and online dispersion in time and space, avoiding the delayed processing method of dispersion after pulverization in traditional processes, so that bamboo fiber is in a controlled dispersion environment at the moment of generation, thereby improving the overall process efficiency and processing effect.
[0017] (3) By controlling the time interval between nano-sizing and dispersion, shear strength and system concentration, the present invention can reduce the contact probability between bamboo fibers and disrupt the hydrogen bond formation conditions, thereby inhibiting the re-binding between fibers from a mechanistic perspective and improving the stability of the system.
[0018] (4) The bamboo fiber ultra-nano powder prepared by the method of the present invention has a more concentrated particle size distribution and significantly reduced agglomerates. It is not easy to settle or re-agglomerate during storage or redispersement, and has good dispersion stability and reusability.
[0019] (5) By eliminating intermediate storage units and constructing a closed continuous conveying path, the present invention ensures that the material is always in a flowing state throughout the entire processing process, avoiding structural changes caused by stagnation, thereby improving the continuity and stability of the production process.
[0020] (6) Since effective dispersion is achieved instantly at the nanoscale, the need for subsequent repeated crushing or long-term shearing is reduced, thereby reducing overall energy consumption and improving output efficiency per unit time, which has good industrial application value.
[0021] (7) By optimizing the dispersion path rather than simply increasing the crushing strength, the present invention achieves nano-sized structure while avoiding excessive mechanical damage, which is beneficial to retaining the aspect ratio and crystal structure of bamboo fiber, thereby enhancing its reinforcing effect in composite materials. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the overall process of the present invention. Detailed Implementation
[0023] Example 1: Please refer to Figure 1A method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select moso bamboo raw materials, remove the outer skin and nodes, and then crush them into bamboo pieces with a particle size of about 10mm using a crusher; The bamboo strips were added to a 6% sodium hydroxide solution and treated at 100°C for 2 hours. After treatment, the bamboo fiber is repeatedly washed with deionized water until the pH of the washing solution is 7.0, thus obtaining pretreated bamboo fiber.
[0024] (2) Pulping and coarse fiber desiccant The pretreated bamboo fiber was added to deionized water at a solid content of 5% and stirred at 1500 rpm for 30 minutes. Subsequently, a disc mill was used for coarse defiber treatment for 40 minutes to obtain primary bamboo fiber pulp.
[0025] (3) Continuous nano-pulverization The primary bamboo fiber pulp is continuously pumped to a high-pressure homogenizer at a flow rate of 2 m / s for nano-sizing. The homogenization pressure was set to 80 MPa, and the process was repeated twice to dissociate the bamboo fiber into nano-sized fiber units, thus obtaining a nano-sized bamboo fiber suspension system.
[0026] (4) Time-limited online dispersion and anti-aggregation treatment The nanoscale bamboo fiber suspension system obtained in step (3) was directly transported to an online high-shear disperser through a 1.2m long closed pipe without intermediate storage. The time interval between the outlet of the nano-powder and the inlet of the online disperser is controlled to be 1.5 s; In the online high-shear disperser, a shear rate of 12000 s is applied to the system. -1 The continuous shearing action, while adjusting the solid content of the system to 2% and controlling the system temperature at 30℃, is used to suppress secondary aggregation between fibers.
[0027] (5) Continuous and stable conveying The bamboo fiber suspension system obtained in step (4) is continuously transported through a closed pipeline at a flow rate of 1.5 m / s. No buffer tank is set up during the transportation process so that the system is always in a flowing state. The transportation time is 3 minutes.
[0028] (6) Dry into powder The bamboo fiber suspension system was dried by spray drying, with the inlet air temperature set at 180℃ and the outlet air temperature at 85℃, to obtain bamboo fiber ultra-nano powder.
[0029] Example 2 A method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select moso bamboo raw materials, remove the outer skin and nodes, and then crush them into bamboo pieces with a particle size of about 15mm using a crusher; The bamboo strips were added to an 8% sodium hydroxide solution and treated at 110°C for 3 hours. After treatment, the bamboo fiber is repeatedly washed with deionized water until the pH of the washing solution is 7.0, thus obtaining pretreated bamboo fiber.
[0030] (2) Pulping and coarse fiber desiccant The pretreated bamboo fiber was added to deionized water at a solid content of 6%, and stirred at 1800 rpm for 25 minutes. Subsequently, a conical mill was used for coarse defiber treatment for 50 minutes to obtain primary bamboo fiber pulp.
[0031] (3) Continuous nano-pulverization The primary bamboo fiber pulp is continuously pumped to a high-pressure homogenizer at a flow rate of 3 m / s for nano-sizing. The homogenization pressure was set to 100 MPa and the process was repeated three times to dissociate the bamboo fiber into nano-sized fiber units, thus obtaining a nano-sized bamboo fiber suspension system.
[0032] (4) Time-limited online dispersion and anti-aggregation treatment The nanoscale bamboo fiber suspension system obtained in step (3) was directly transported to an online high-shear disperser through a 1.5m long closed pipe without intermediate storage. The time interval between the outlet of the nano-powder and the inlet of the online disperser is controlled to be 2.0 s; In the online high-shear disperser, a shear rate of 15000 s is applied to the system. -1 The continuous shearing action, while adjusting the solid content of the system to 2.5% and controlling the system temperature at 35℃, is used to suppress secondary agglomeration between fibers.
[0033] (5) Continuous and stable conveying The bamboo fiber suspension system obtained in step (4) is continuously transported through a closed pipeline at a flow rate of 2.0 m / s. No buffer tank is set up during the transportation process so that the system is always in a flowing state. The transportation time is 4 min.
[0034] (6) Dry into powder The bamboo fiber suspension system was dried by spray drying, with the inlet air temperature set at 190℃ and the outlet air temperature at 90℃, to obtain bamboo fiber ultra-nano powder.
[0035] Example 3 A method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select raw bamboo and crush it into bamboo pieces with a particle size of about 8mm; The bamboo strips were added to a 4% sodium hydroxide solution and treated at 90°C for 1.5 hours. After treatment, the bamboo fibers are washed with deionized water until neutral to obtain pretreated bamboo fibers.
[0036] (2) Pulping and coarse fiber desiccant Pretreated bamboo fiber was added to deionized water at a solid content of 4% and stirred at 1200 rpm for 35 minutes. Subsequently, a high-shear disperser was used for coarse defiber treatment for 30 minutes to obtain primary bamboo fiber pulp.
[0037] (3) Continuous nano-pulverization The primary bamboo fiber pulp is continuously pumped to a microfluidic homogenizer at a flow rate of 1.5 m / s for nano-sizing. The homogenization pressure was set to 60 MPa, and the process was repeated twice to obtain a nanoscale bamboo fiber suspension system.
[0038] (4) Time-limited online dispersion and anti-aggregation treatment The nanoscale bamboo fiber suspension system obtained in step (3) is directly transported to an online high-shear disperser through a closed pipe with a length of 0.8m. The time interval between the nano-powder outlet and the disperser inlet is controlled to be 0.8 s; A shear rate of 10000s is applied in the disperser. -1 The continuous shearing action was used to adjust the solid content of the system to 1.5% and the temperature to 25℃.
[0039] (5) Continuous and stable conveying The treated bamboo fiber suspension system was continuously conveyed at a flow rate of 1.0 m / s for 2 minutes, without the use of a storage tank.
[0040] (6) Dry into powder The suspension system was dried by freeze-drying to obtain bamboo fiber ultra-nano powder.
[0041] Example 4 A method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select raw bamboo and crush it into bamboo pieces with a particle size of about 12mm; The bamboo strips were added to a 5% sodium carbonate solution and treated at 95°C for 2.5 hours. After treatment, the bamboo fibers are washed until neutral to obtain pretreated bamboo fibers.
[0042] (2) Pulping and coarse fiber desiccant Pretreated bamboo fiber with a solid content of 7% was added to deionized water and stirred at 1600 rpm for 30 minutes. Subsequently, a disc mill was used for coarse defiber treatment for 45 minutes to obtain primary bamboo fiber pulp.
[0043] (3) Continuous nano-pulverization The slurry is continuously pumped to a high-pressure homogenizer at a flow rate of 2.5 m / s for nano-sizing. The homogenization pressure was set to 120 MPa, and the process was repeated three times to obtain a nanoscale bamboo fiber suspension system.
[0044] (4) Time-limited online dispersion and anti-aggregation treatment The nanoscale bamboo fiber suspension system obtained in step (3) is directly transported to the multi-stage rotor-stator disperser through a closed pipe with a length of 1.0m. The time interval between nano-sizing and dispersion was controlled to be 1.0 s; A shear rate of 18000 s was applied during the dispersion process. -1 Meanwhile, the solid content of the system was controlled at 3%, and the temperature was controlled at 40℃.
[0045] (5) Continuous and stable conveying The treated suspension system was continuously conveyed at a flow rate of 2.2 m / s for 3.5 min, without any buffering device.
[0046] (6) Dry into powder The suspension system was dried using an airflow drying method to obtain bamboo fiber ultra-nano powder.
[0047] Comparative Example 1 A method for preparing bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select raw bamboo, remove the outer skin and nodes, and then crush it into bamboo pieces with a particle size of about 10mm. Bamboo strips were added to a 6% sodium hydroxide solution and treated at 100°C for 2 hours. After treatment, the bamboo fibers are washed with deionized water until neutral to obtain pretreated bamboo fibers.
[0048] (2) Pulping and coarse fiber desiccant Add the pretreated bamboo fiber to deionized water at a solid content of 5% and stir at 1500 rpm for 30 min. Subsequently, a disc mill was used for coarse defiber treatment for 40 minutes to obtain primary bamboo fiber pulp.
[0049] (3) Nanoparticle pulverization The primary bamboo fiber pulp is transported to a high-pressure homogenizer via a pump for nano-sizing treatment. The homogenization pressure is 80 MPa, and the process is repeated twice to obtain a nano-scale bamboo fiber suspension system.
[0050] (4) Delayed storage The nanoscale bamboo fiber suspension system obtained in step (3) is introduced into a storage tank and left to stand for 20 minutes.
[0051] (5) Subsequent decentralized processing The stored suspension system was then transported to a high-shear disperser for dispersion treatment at a shear rate of 12000 s⁻¹. -1 The processing time is 10 minutes.
[0052] (6) Dry into powder The dispersed suspension system was dried by spray drying to obtain bamboo fiber powder.
[0053] Comparative Example 2 A method for preparing bamboo fiber ultra-nano powder includes the following steps: (1) Raw material pretreatment Select raw bamboo and crush it to a particle size of approximately 12mm; The solution was treated at 95°C for 2 hours in a 5% sodium hydroxide solution. Wash until neutral to obtain pretreated bamboo fiber.
[0054] (2) Pulping and coarse fiber desiccant Add the pretreated bamboo fiber to water at a solid content of 6% and stir at 1600 rpm for 25 minutes. The primary bamboo fiber pulp was then processed by a conical mill for 45 minutes.
[0055] (3) Continuous nano-pulverization The slurry was fed into a high-pressure homogenizer for nano-sizing treatment. The homogenization pressure was 90 MPa, and the process was repeated twice to obtain a nano-scale bamboo fiber suspension system.
[0056] (4) Buffer storage The nanoscale bamboo fiber suspension system is temporarily stored in a buffer tank for 5 minutes to adjust the subsequent processing cycle.
[0057] (5) Decentralized processing The material in the buffer tank is conveyed to a high-shear disperser for dispersion treatment, with a shear rate of 13000 s. -1 .
[0058] (6) Dry into powder The dispersed system was treated by spray drying to obtain bamboo fiber powder.
[0059] Comparative Example 3 (1) Raw material pretreatment Select raw bamboo and crush it to a particle size of approximately 10mm. The solution was treated at 100°C for 2 hours in a 6% sodium hydroxide solution. Wash until neutral to obtain pretreated bamboo fiber.
[0060] (2) Pulping and coarse fiber desiccant Add the pretreated bamboo fiber to water at a solid content of 5% and stir at 1500 rpm for 30 minutes. The primary bamboo fiber pulp was then processed using a disc mill for 40 minutes.
[0061] (3) Nanoparticle pulverization The slurry was fed into a high-pressure homogenizer for nano-sizing treatment. The homogenization pressure was 80 MPa, and the process was repeated twice to obtain a nano-scale bamboo fiber suspension system.
[0062] (4) Direct drying The nanoscale bamboo fiber suspension system obtained in step (3) was dried directly by spray drying without dispersion treatment to obtain bamboo fiber powder.
[0063] To verify the effectiveness of the examples and comparative examples, the following comparative experiment was designed: To ensure the validity of the comparison, the following conditions must be kept consistent: Raw materials: bamboo from the same batch; Preprocessing conditions: consistent; Solid content: 5% ± 0.2%; Drying method: spray drying; Ambient temperature: 25℃; Experimental steps Samples from Examples 1–4 and Comparative Examples 1–3 were prepared respectively; Prepare 1wt% suspensions from each sample; Particle size (D50) was tested separately. Record the settlement after allowing it to stand for 24 hours. BET specific surface area test was performed on the dried powder. Each experiment was repeated 3 times and the average value was taken.
[0064] ; (1) Particle size comparison: Example of the present invention: 78–92nm; Comparative example: 165–240nm; This scheme significantly improves the degree of nano-sizing and reduces the particle size by more than 50%.
[0065] (2) Dispersion stability: The sedimentation rate of the present invention is 6%–9%; the comparative example is 28%–42%; the present invention significantly inhibits agglomeration and improves the stability of the system by about 4–6 times.
[0066] (3) Specific surface area: In this invention: 40–45 m² 2 / g; Comparative examples: 15–22m 2 / g; This scheme significantly increases the effective specific surface area, indicating more complete dispersion.
[0067] In summary, the experimental results show that this invention, by performing online dispersion within an extremely short time window after bamboo fiber nanoforming and avoiding intermediate storage, effectively suppresses hydrogen bond reconstruction and agglomeration between bamboo fibers. This results in bamboo fiber micropowder with smaller particle size, higher specific surface area, and significantly improved dispersion stability. Compared with existing technologies, this invention demonstrates significant improvements in structural dispersibility and stability, exhibiting outstanding substantive features and remarkable progress.
[0068] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A continuous method for preparing highly dispersible bamboo fiber ultra-nano powder, characterized in that, Includes the following steps: S1. Bamboo raw materials are pretreated by lignin removal and mechanically defiberized to obtain bamboo fiber pulp; S2. The bamboo fiber pulp is continuously fed to the nano-pulverization unit for high-intensity mechanical defiberization, so that the bamboo fiber is dissociated into nano-scale fiber units and forms an instantaneous dispersion system in a high surface energy state. S3. Within the time window before the hydrogen bond recombination of the nanoscale fiber units, the system obtained in step S2 is directly introduced into an online high-shear dispersion field within 0.1 to 10 seconds without intermediate storage. S4. In the online high-shear dispersion field, a continuous shearing action is applied to the nanoscale bamboo fiber to keep the fiber units in a separated state in the flow state, and the re-binding between fibers is suppressed by controlling the coupling relationship between shear intensity and system concentration. S5. A stable and dispersed bamboo fiber nano-dispersion system is output under continuous flow conditions, and highly dispersed bamboo fiber ultra-nano powder is obtained after drying.
2. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The time interval between step S2 and step S3 shall not exceed 5 seconds.
3. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The time interval between step S2 and step S3 shall not exceed 2 seconds.
4. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: In step S2, nano-pulverization increases the specific surface area of bamboo fiber to 5 to 50 times that of the original fiber.
5. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The shear rate in step S4 is 8000–30000 s. -1 Furthermore, the solid content of the system is controlled between 0.5% and 3%, and the two satisfy the following relationship: When the solid content increases, the shear rate is increased simultaneously to maintain the average spacing between fibers.
6. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The outlet of the nano-pulverization unit is directly connected to the inlet of the online dispersion unit via a short-distance closed conveying structure, with a connection path length not exceeding 2m.
7. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The system remains in a turbulent state throughout steps S3 to S5, with a Reynolds number greater than 4000.
8. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: In step S3 or S4, a nonionic dispersant with a mass fraction of 0.01% to 0.2% is added.
9. The method for continuous preparation of highly dispersible bamboo fiber ultra-nano powder according to claim 1, characterized in that: The redispersible particle size (D50) of the obtained bamboo fiber ultra-nano powder in water is 100–300 nm, and there is no obvious sedimentation within 24 hours.