CN114654552A

CN114654552A - Method for cleanly and efficiently preparing bamboo fibers

Info

Publication number: CN114654552A
Application number: CN202210231590.3A
Authority: CN
Inventors: 张蔚; 姚文斌; 龚震鸿; 冯俊哲
Original assignee: Jiyang College of Zhejiang A&F University
Current assignee: Jiyang College of Zhejiang A&F University
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2022-06-24

Abstract

The invention relates to the field of bamboo processing and utilization, in particular to a method for cleanly and efficiently preparing bamboo fibers. Firstly, cutting off bamboo roots and later parts of the whole bamboo, then slicing the whole bamboo on a slicer, removing bamboo inner joints and bamboo yellow, and sawing according to the use requirements of fibers to obtain fixed-length bamboo chips; then carrying out high-temperature saturated steam softening treatment, wherein the water content of the softened bamboo chips is not lower than 55%; beating and splitting processing is carried out on bamboo beating equipment, and fiber bundles are obtained through separation. The invention provides a new process for preparing the coarse bamboo fiber by the cooperation of moist heat and force, which is clean and environment-friendly and simplifies the bamboo fiber processing process and equipment; meanwhile, a novel method for splitting bamboo chips by mechanical knocking assisted water hammer is provided. The structure and performance characteristics of the bamboo are fully utilized, the loading mode is changed, the bamboo fibers can be reduced by continuously beating the bamboo chips for fiber splitting, the physical structure and strength of the bamboo fibers are kept, and meanwhile beating vibration is beneficial to cracking and falling of the bamboo matrix; the bamboo chips are conveyed by the conveying belt and continuously hit, so that the problems of fiber winding and fiber breakage in fiber opening in the conventional method are solved.

Description

Method for cleanly and efficiently preparing bamboo fibers

Technical Field

The invention relates to the field of bamboo processing and utilization, in particular to a method for cleanly and efficiently preparing bamboo fibers.

Background

The bamboo belongs to stalk plants, the fiber bundles in the bamboo are arranged in parallel along the length direction and comprise fiber bundles, and the bamboo can be regarded as a composite material consisting of the fiber bundles and a thin-wall matrix tissue and belongs to a unidirectional fiber reinforced composite material. After the bamboo material is softened, the strength of the fiber bundle is far greater than that of the matrix structure, and the fiber bundle and the matrix are connected through a weak interface. The bamboo fiber extraction is to separate fiber bundles to obtain bundle fibers consisting of single fibers.

Bamboo fiber has begun to be applied to the field of composite materials such as mattresses, automotive interiors and the like as a novel natural fiber. At present, the domestic method for processing bamboo fiber mainly adopts a chemical mechanical method. Firstly, flattening or splitting bamboo wood, carrying out alkali-heat pretreatment, applying extrusion load to softened bamboo chips through a plurality of groups of paired compression rollers of a rolling fiber splitting machine to realize separation of bamboo fiber bundles, and then carrying out acid pickling dehydration, drying, impurity removal and other processes to obtain bamboo fibers. The prior art mainly has the following defects:

(1) in the process of rolling and splitting, the physical structure and the strength of the bamboo fiber bundle are damaged to different degrees while the applied extrusion load damages the matrix; in the process, along with fiber separation, fiber winding on the press roll and fiber breakage caused by the fiber winding can occur. The bamboo wood matrix tissue is attached to the surface of the fiber bundle and is not easy to fall off due to the action of rolling extrusion force, and the burden of fiber post-treatment is increased.

(2) The rolling and fiber opening are realized by a series of double-roller extrusion and fiber opening, certain requirements are provided for the rigidity of bamboo chips, and the direct rolling and processing is generally carried out without removing tabasheer. Therefore, the coarse fiber can be obtained after a series of procedures such as fiber cutting, impurity removal and dust removal after fiber opening, the process flow is long, and a plurality of auxiliary supporting devices are provided.

(3) The alkali pretreatment operation is simple, but the components and the strength of the bamboo fibers are affected, and the subsequent acid neutralization and waste liquid treatment are carried out, so that the method is not environment-friendly.

In a word, the existing chemical mechanical method adopts chemical agents to remove components such as lignin in bamboo wood, and then separates fibers through mechanical external force; the bamboo is subjected to alkali heat treatment and then is split by a rolling method, and the separated bamboo fiber has good alignment and high separation degree and is used for a fiber processing production line; but the chemical treatment and rolling process has great influence on the quality of the fiber, has low environmental protection property and is not beneficial to industrial production.

Aiming at the problem that the existing chemical mechanical method cannot be avoided, the patent researches the manual bamboo chip knocking fiber opening method and discovers that: the properly softened bamboo chips are repeatedly knocked to obtain uniformly separated fiber bundles, and the damage to the fibers is small due to the fact that knocking force is not large. Combined with the analysis of bamboo structure and characteristics, it can be found that: when the bamboo chips are knocked, the matrix tissue can be damaged through knocking force due to the large strength difference of the two phases of the bamboo; meanwhile, the bamboo chips are repeatedly hit to enable the cracks of the matrix to expand, and the weak interface characteristics between two phases of the bamboo are just met, so that the fiber bundles are separated; however, since the pectin and other matrix impurities are attached to the surface of the fiber bundle, the bundle fiber can be obtained only by cleaning and other steps after the bamboo chips are knocked to be split, the patent proposes a splitting mode of mechanical beating and pressurized water beating combination, and pressurized water continuously permeates in the splitting process of the bamboo chips, so that the crack propagation of the matrix and the fiber debonding and separation are facilitated. In addition, for the pretreatment of bamboo processing, high-temperature saturated hot steam softening of bamboo is good in effect and high in efficiency, the existing alkali pretreatment process is replaced, waste water and waste liquid discharge in the crude fiber extraction process is avoided, and the bamboo fiber processing process is environment-friendly.

Based on the reasons, the invention provides a method for cleanly and efficiently preparing bamboo fibers by wet-heat-mechanical synergistic fiber opening.

Disclosure of Invention

The invention aims to solve the technical problem of providing a clean and efficient method for preparing bamboo fibers.

The invention is realized by the following steps:

firstly removing bamboo roots and later parts of the whole bamboo, then slicing the whole bamboo on a bamboo slicer, removing bamboo inner joints and a tabasheer layer, then sawing according to the use requirement of fibers (directly sawing fresh bamboo, and sawing other bamboo after soaking in water for 5-7 days) to obtain fixed-length bamboo slices, then carrying out high-temperature saturated steam softening treatment, wherein the water content of the softened bamboo slices is not less than 55%, and finally beating on bamboo beating equipment for splitting, and separating to obtain fiber bundles.

Further, the bamboo striking equipment adopts mechanical striking matched with pressure water spraying.

Furthermore, the pressure of the pressurized water is 0.3-0.7MPa, and the temperature is 40-60 ℃.

Furthermore, the bamboo striking equipment strikes the softened bamboo in the radial direction and simultaneously sprays and permeates the bamboo by matching with pressure water.

Furthermore, the bamboo striking equipment utilizes a transmission belt to transmit bamboo chips and is matched with continuous mechanical striking.

Furthermore, the beating frequency of the mechanical beating is matched with the bamboo chip movement speed, the mechanical beating frequency is 30-50 times/min, and the bamboo chip movement speed is 3-5 m/min.

And further, the fiber bundle enters a cleaning process, impurities on the surface of the fiber are further washed by adopting pressure water, the fiber bundle is dewatered by an extrusion roller along with the movement of a transmission belt to obtain clean bundle fiber, and the bamboo fiber is obtained according to a subsequent conventional drying process.

Furthermore, the temperature of the high-temperature saturated steam is 160-180 ℃, the pressure is 0.6-1MPa, and the softening time is 20-30 min.

The invention has the following advantages:

1) the continuous beating fiber-opening method provided by the invention accords with the structural characteristics and the mechanical principle of bamboo wood, and can effectively reduce the damage to fibers in the fiber-opening process and keep the fiber tissue complete by utilizing the transverse loading and longitudinal cracking characteristics of the bamboo wood. The impact shock force also helps in shedding of the matrix tissue.

2) The invention adopts continuous beating to assist the pressure water to beat and split the fibers, and the pressure water enters the split bamboo after being hammered and is interacted with the mechanical beating, thereby effectively improving the fiber splitting effect and being beneficial to removing the basal tissues such as pectin and the like attached to the fiber bundles.

3) The invention provides a novel method for splitting bamboo chips by mechanical knocking and water hammer assistance, which fully utilizes the structural and performance characteristics of bamboo wood and keeps the physical structure and strength of bamboo fibers to the maximum extent; the transmission belt is used for transmitting the bamboo chips to match with continuous beating, so that the problems of fiber winding on a roller and fiber breakage in the conventional rolling and fiber splitting process are solved.

4) The bamboo chips are subjected to damp-heat pretreatment by adopting high-temperature saturated steam, the damage of chemical treatment to the fiber strength and the environmental pollution are avoided, the operation is simple, convenient and time-saving, the bamboo strength is basically not damaged, and the clean production is realized.

5) The method for continuously beating the bamboo chips on the transmission belt to open the fibers does not set requirements on the length and the rigidity of the bamboo chips, and the fibers are opened after the yellow color and the fixed length of the bamboo chips are removed, so that the processing technology is simplified, and meanwhile, fiber cutting and impurity removing equipment is reduced.

The method has no limit on the length of the bamboo chips, and can process the fixed-length bamboo chips according to the use requirement to obtain the fixed-length fibers. The fiber cutting process and equipment in the rolling process are eliminated;

the bamboo chips are processed after yellow removal and are matched with water hammer in fiber opening, so that impurities such as matrix tissues and the like are removed and washed away, and dust removal and impurity removal equipment after fiber opening in a rolling process can be omitted.

6) This patent can be used to the crude fiber of high quality fibre and draw. According to the structural characteristics of bamboo, the bamboo chips are layered and then processed respectively, which is an effective method for improving the uniformity of the fibers. After the bamboo chips are processed by removing nodes and layering (bamboo green layer, bamboo meat layer and tabasheer layer) on a bamboo chip dividing machine, the fibers with different scales and uniformity can be obtained by processing according to the method of the patent, and particularly, the fibers extracted from the bamboo green layer can be used for processing textile fibers.

Drawings

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a schematic view of the present invention.

Fig. 3 is a schematic view of the structure of the transmission device and the mechanical striking device.

Fig. 4 is a schematic structural diagram of the transmission device.

Fig. 5 is a schematic view of a single row striking device.

Detailed Description

The method for cleanly and efficiently preparing the bamboo fibers can be realized by the system shown in figure 2 and mainly comprises a high-temperature steam softening system I, a fiber opening system II and a cleaning system III.

-high temperature steam softening system: mainly comprises a saturated steam generator and a pressure tank (not shown), and is used for bamboo softening treatment. The saturated steam generator is used for generating high-temperature saturated steam, and the pressure tank is used for placing and softening bamboo chips. When in softening, the bamboo chips are placed in a pressure tank in layers, high-temperature saturated steam is introduced after a tank door is closed, the temperature in the tank is quickly increased to 160-. At the moment, the water content of the bamboo chips is between 55 and 75 percent.

-a splitting system: as shown in fig. 3, it is mainly composed of a transmission device 1, a mechanical striking device 2, and a pressure water striking device 3 (not shown). The transmission device 1 takes a motor as power, a transmission belt is driven by a speed reducer to convey the bamboo chips, the transmission belt can adopt a chain plate transmission mode, and the chain plate can bear certain mechanical force, temperature and water hammer, so that the continuous motion of the bamboo chips is ensured.

The mechanical striking device 2 consists of 20-30 rows of independent striking devices, each row can be provided with 2-8 striking heads, and the striking heads of each row of striking devices perform vertical reciprocating motion to strike the bamboo chips. The vertical reciprocating motion of the striking device can be realized by mechanical mechanisms such as an eccentric wheel and the like, and can also be realized by pneumatic, namely the reciprocating motion of a cylinder piston. The pressure water beating device 3 (not shown) is composed of a plurality of rows, and each row is provided with a plurality of nozzles which are arranged at intervals with the beating device. After the water is pressurized by a high-pressure pump, the bamboo chips are sprayed for assisting fiber opening.

The fiber splitting system is arranged at the rear end of the high-temperature steam softening system, so that bamboo chips can be conveniently and quickly placed into the fiber splitting conveying belt.

In one embodiment of the invention:

as shown in figure 4, the transmission device 1 drives the chain plate conveyor belt by a motor through chain transmission to enable the bamboo chips to move continuously. The reducing motor 11 drives the driving chain wheels 12 on two sides of the chain plate 15 to rotate through the shaft coupling, the driving chain wheels 12 drive the driven chain wheels 14 to move through the chain 13, so that the chain plate 15 arranged on the chain 13 continuously moves, and the continuous linear conveying of the bamboo chips is completed. The driving sprocket 12 and the driven sprocket 14 are mounted on the frame 10 through a bearing. The conveying chain plates 15 are supported by rollers 16 on the upper and lower surfaces. The roller 16 is mounted on the frame 10 by means of a bearing block 17. The rollers 16 are arranged in parallel along the chain plate movement direction, the number of the rollers is the same as the row number of the striking heads, and the axial line of the upper layer roller corresponds to the center of a striking hammer 26 to ensure that striking force is born by the rollers 16.

As shown in fig. 5, in the mechanical striking device 2, a striking frame 21 is mounted on a frame 10, the bottom of a cylinder 22 is mounted on a top beam of the striking frame 21 through a bolt connection, the end of a piston rod 23 is connected with an ear plate 25 welded on a movable beam 24 through a pin, and the connecting end of a striking hammer 26 (which may be a square column) is connected with the movable beam 24 through a thread and is fastened by a nut 261 and a pair of wedge-shaped anti-loosening gaskets 262. The striking frame 21 can be welded by channel steel, the openings of the two side beam columns are opposite to form a guide rail 27, and the lower ends of the guide rails on the two sides of the striking frame 21 are welded with connecting plates 28 and are connected with the frame 10 through bolts. The movable beam 24 is provided at both ends with rollers 29 which can move up and down along the guide rails 27. The cylinder 22 strikes the bamboo chips by reciprocating up and down a striking hammer 26 mounted on the moving beam 24. When in beating, each row of beating hammers are sequentially beaten to ensure that the resistance on the chain plate conveying belt is minimum.

-a cleaning system: as shown in fig. 2, the apparatus is composed of a fiber cleaning apparatus 4, a dewatering apparatus 5, and a cleaning and conveying apparatus 6. The fiber cleaning device 4 and the pressurized water beating device 3 are the same water circulation system, and the system (not shown) mainly comprises: high-pressure pump, heating element, high-pressure pipeline and shower nozzle, filtering component and relief valve, water tank etc.. The dewatering device 5 dewaters the fibres by means of squeeze rolls, which can be adjusted by means of springs. The cleaning device is arranged at the rear half part of the cleaning conveying belt and can also be crossed with the cleaning.

The conveying belt feeding end of the cleaning and conveying device 6 is located below the fiber opening conveying belt discharging end, when bamboo chips are transversely placed for feeding, after fibers are opened by hammering, the fibers sequentially turn over and fall onto the cleaning and conveying belt, and the fibers are comprehensively cleaned.

The specific operation process is as follows:

1) putting the fresh bamboo chips with fixed length and removed yellow into a pressure tank for high-temperature saturated steam softening treatment (at the temperature of 160-;

2) the treated bamboo chips are directly placed on the fiber-opening conveying belt, and the bamboo chips can be arranged horizontally in sequence so as to obtain complete flushing in the cleaning process. The conveying belt carries out slow motion feeding, the feeding speed is 3-5m/min, the knocking speed is 30-50 times/min, and the bamboo moving speed is matched with the frequency of a beating hammer, so that the bamboo chips are repeatedly beaten, and the bamboo chips can be guaranteed to be beaten and split.

The pressure water pressure is 0.3-0.7MPa, the temperature is 40-60 ℃, the water pressure is preferably not to damage the fiber, and the water temperature is high to keep the plasticity of the pretreated bamboo chips and help the shedding of the matrix. The single-row water-beating spray head and the single-row beating device are arranged at intervals to play a role in assisting fiber opening and flushing. Under the interaction of the beating hammer of the fiber opening device and the pressure water, the bamboo chip matrix is damaged, cracks are continuously expanded, and fiber bundles are effectively separated.

Under the synergistic action of mechanical striking and pressure water, the damp and hot modified bamboo wood is knocked in the radial direction to destroy the matrix structure of the bamboo wood, and meanwhile, the bamboo wood is sprayed and permeated by matching with the pressure water, so that the propagation of matrix cracks along two weak interfaces between the fiber matrix is accelerated; along with the movement of the bamboo chips, the bamboo fibers are repeatedly struck, and are continuously debonded and separated.

3) And (3) the fiber bundle enters a cleaning process, pressure water is further used for washing away matrix impurities such as pectin on the surface of the fiber, and the fiber bundle is dewatered through a squeezing roller along with the movement of a conveying belt to obtain clean bundle fiber. And then obtaining the coarse bamboo fiber according to the subsequent conventional drying procedure.

Although specific embodiments of the invention have been described above, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the appended claims.

Claims

1. A method for cleanly and efficiently preparing bamboo fibers is characterized by comprising the following steps: firstly cutting bamboo roots and bamboo tips of the whole bamboo, then slicing the whole bamboo on a bamboo slicer, removing tabasheer and bamboo inner joints, sawing according to the use requirement of fibers to obtain fixed-length bamboo slices, then carrying out high-temperature saturated steam softening treatment, wherein the water content of the softened bamboo slices is not lower than 55%, finally carrying out beating and splitting processing on bamboo beating equipment, and separating to obtain fiber bundles.

2. The method for cleanly and efficiently preparing the bamboo fiber according to claim 1, characterized in that: the bamboo striking equipment adopts mechanical striking matched with pressure water spraying.

3. The method for cleanly and efficiently preparing the bamboo fiber according to claim 2, wherein the method comprises the following steps: the pressure of the pressure water is 0.3-0.7MPa, and the temperature is 40-60 ℃.

4. The method for cleanly and efficiently preparing the bamboo fiber according to claim 2, wherein the method comprises the following steps: the bamboo striking equipment strikes the softened bamboo in the radial direction and simultaneously sprays and permeates the bamboo by matching with pressure water.

5. The method for cleanly and efficiently preparing the bamboo fiber according to claim 1, characterized in that: the bamboo striking equipment utilizes a transmission belt to transmit bamboo chips and is matched with continuous mechanical striking.

6. The method for cleanly and efficiently preparing the bamboo fiber according to claim 5, wherein the method comprises the following steps: the beating frequency of the mechanical beating is matched with the bamboo chip movement speed, the mechanical beating frequency is 30-50 times/min, and the bamboo chip movement speed is 3-5 m/min.

7. The method for cleanly and efficiently preparing the bamboo fiber according to claim 1, characterized in that: and the fiber bundle enters a cleaning process, impurities on the surface of the fiber are further washed by adopting pressure water, the fiber bundle is dewatered by an extrusion roller along with the movement of a transmission belt to obtain clean bundle fiber, and the bamboo fiber is obtained according to a subsequent conventional drying process.

8. The method for cleanly and efficiently preparing the bamboo fiber according to claim 1, characterized in that: softening the high-temperature saturated steam, wherein the temperature of the high-temperature saturated steam is 160-180 ℃, the corresponding pressure is 0.6-1MPa, and the softening time is 20-30 min.