A pretreatment combination device, method and application for straw raw materials

Abstract

The present application relates to a combined device, method and application for pretreatment of straw raw materials, including a leaf sheath removing device and a straw surface rolling device. The leaf sheath removing device includes a first frame, a cavity is formed in the first frame, a U-shaped flexible treatment bag is arranged in the cavity, a feed inlet is formed above the flexible treatment bag, and a cam assembly for driving the movement of the flexible treatment bag and the straw therein is arranged below; a chain knife cutting mechanism is arranged above the first frame; the straw surface rolling device includes a second frame, and a feeding roller group, a fracturing roller group, a hair pulling roller group and a densifying roller group are sequentially arranged side by side in parallel on the second frame. The cam assembly drives the movement of the flexible treatment bag, and the chain knife cutting mechanism cuts the leaf sheaths on the straw surface, realizing the removal of the leaves and leaf sheaths of the straw; the straw surface rolling device realizes the hair pulling, grinding and rolling treatment of the straw by designing four groups of roller structures.

Description

Technical Field

[0001] The present invention relates to the technical field of high added value of crop straws, and particularly relates to a combined device and method for pretreatment of straw raw materials and their applications. Background Art

[0002] China is a veritable large agricultural country. As a result, there is a large amount of crop straw. The straw output has been stable at 800 million tons per year in the past decade. In the past, a large amount of crop straw was mostly burned, which brought serious air pollution problems. Under the "burning ban", the straw is no longer burned, and this "resource in the wrong place" is changing from an "ecological burden" to "green wealth". At present, the comprehensive utilization of straw in China mainly includes five utilization methods: fertilizer utilization, feed utilization, fuel utilization, substrate utilization and raw material utilization. The utilization amounts of the five methods account for 62.1%, 15.4%, 8.5%, 0.7% and 1.0% of the collectable amount of straw respectively. There is still a large space in the utilization of straw as substrate and raw material. The processing of straw-based wood substitute boards not only provides a way for the high added value utilization of crop straws, but also can alleviate the realistic problem of the shortage of wood resources in China. As a natural polymer material, straw has a multi-level pore structure and chemical composition similar to that of wood. Crop straw is also composed of three major components: cellulose, hemicellulose and lignin. Except for raw materials such as rice straw, corn straw and sorghum straw, the cellulose content of most varieties is close to that of wood. Bast fiber raw materials such as hemp and flax contain more cellulose. After degreasing, cotton fiber is almost pure cellulose. However, the ash content of straw is much higher than that of wood, which is caused by a large amount of silicon dioxide in the cell wall on the surface of straw. In addition, in gramineous plants, the content of organic solvent extracts is also relatively high, because the cells of gramineous plants contain more fats and waxes than wood. These silicon dioxides and cutin wax-like films will all affect the penetration of adhesives and the bonding strength to varying degrees, and become one of the main technical problems restricting the development of the crop straw composite material industry.

[0003] China has started to research and develop non-wood plant artificial boards since the 1950s, and has also accumulated a lot of experience in the development and utilization of non-wood plant raw materials. However, due to the high content of silicon dioxide seriously hindering the gluing process and reducing the bonding strength between the adhesive and the straw, this bottleneck has also severely restricted the development of straw-based artificial boards in China. It was not until the application of isocyanate in the production of straw-based artificial boards that this problem was partially solved. However, using isocyanate to produce straw-based artificial boards is costly, and there are also many new problems such as poor initial tack of the board embryo and difficult demolding.

[0004] The key to solving this problem lies in the pretreatment and modification of the surface of crop straws. Through treatment, part or all of the silica and wax components on the straw surface are removed, the surface roughness of the straw is increased, channels are opened for the infiltration of adhesives, making it easy to bond and improving the gluing performance. The pretreatment of the straw surface can generally be divided into physical methods, chemical methods, physicochemical methods, and biological methods. Physical methods include hydrothermal treatment, hot grinding, steam explosion, ray treatment, plasma treatment, mechanical rolling, etc. Chemical methods include alkali treatment, addition of coupling agents, acetylation treatment, etc. The most important biological treatment is the use of various enzyme treatments. The above treatment methods improve the wettability of the straw and enhance the penetration of the adhesive by changing the surface roughness of the straw, destroying the surface vascular bundles, and degrading part of the cellulose, thereby improving the gluing performance of straw-based panels. However, corresponding hazards are also brought: for example, hydrothermal treatment will reduce the mechanical properties of the straw, chemical treatment methods will result in the generation of highly toxic waste, steam explosion requires a high energy input, enzyme treatment requires a long time, the cost of coupling agent treatment is relatively high, etc. Moreover, the above treatment methods are mostly limited to laboratory research, with low treatment efficiency and it is difficult to meet the needs of large-scale industrial production. Summary of the Invention

[0005] In view of the above-mentioned prior art, the object of the present invention is to provide a combined device, method and application for the pretreatment of straw raw materials.

[0006] To achieve the above object, the present invention provides a combined device for the pretreatment of straw raw materials, including a leaf and sheath removal device and a straw surface rolling device. The leaf and sheath removal device includes a first frame, a cavity is provided inside the first frame, a U-shaped flexible treatment bag is arranged inside the cavity, a feeding port is opened above the flexible treatment bag, and a cam assembly is arranged below the flexible treatment bag for driving the movement of the flexible treatment bag and the straw inside the bag; a chain knife cutting mechanism is arranged above the first frame, and a feeding port is arranged between the first frame and the chain knife cutting mechanism;

[0007] The straw surface rolling device includes a second frame, a feeding roller group, a fracturing roller group, a hair-raising roller group and a densifying roller group are arranged in parallel and side by side on the second frame. The feeding roller group, the fracturing roller group and the densifying roller group are driven to rotate by a first driving component, and the hair-raising roller group is driven to rotate by a second driving component.

[0008] By adopting the above technical solution, the straw enters horizontally from the feeding port into the feeding port of the flexible treatment bag. The movement of the flexible treatment bag and the straw inside the bag is driven by the cam assembly, causing the straw placed in the flexible treatment bag to perform a parabolic action. Through upward throwing, natural falling, and friction between the straws, the leaves on the surface of the straw fall off; the leaf sheaths of the straw are cut and torn by the chain knife cutting mechanism to remove the leaf sheaths of the straw; the straw is pulled in by the feeding roller group, and then the surface of the straw is roughened, polished, fractured, and fluffed by the fracturing roller group, the fluffing roller group, and the densifying roller group. The internal straw core part is densified, the silica layer on the surface is partially damaged and removed, and the internal tissue part of the straw skin is partially exposed, increasing the roughness and the wettability of the straw surface; the treatment of the fracturing roller group opens up some adhesive penetration channels between the surface and the inside of the straw, accelerating the penetration of the adhesive, and providing a suitable straw raw material for the next step of preparing straw parallel overlapping composites using conventional water-based adhesives.

[0009] Preferably, the cam assembly includes a plurality of cams and a cam motor. The cam motor is installed on the outer wall of the first frame. The plurality of cams are coaxially fixedly connected and are all rotatably arranged in the cavity. The output shaft of the cam motor is coaxially fixedly connected to the plurality of cams, and the plurality of cams can abut against the flexible treatment bag during rotation.

[0010] By adopting the above technical solution, during operation, the plurality of cams rotate around the axis. The cam group is placed outside the flexible treatment bag and can push the flexible treatment bag to move back and forth during rotation, forcing the straw in the flexible treatment bag to roll forward and backward and up and down. During the movement, the leaf sheaths rub against each other, causing the leaves and leaf sheaths to be partially broken.

[0011] Preferably, a plurality of rectangular holes are opened at the bottom of the flexible treatment bag; an opening is provided on the side wall of the first frame, and a viewing window for opening and closing the opening is rotatably connected to the side wall of the first frame.

[0012] By adopting the above technical solution, during use, the cut leaves and leaf sheaths after treatment can fall from the rectangular holes. The viewing window is convenient for observing the state inside the flexible treatment bag and the cavity. When cleaning is required, opening the viewing window is convenient for dealing with the fallen leaves and leaf sheaths.

[0013] Preferably, a limiting roller is provided between the opposite inner walls of the first frame. The limiting roller penetrates the flexible treatment bag and is located in the upper-middle part of the flexible treatment bag.

[0014] By adopting the above technical solution, the limiting roller is provided to prevent the straw in the flexible treatment bag from rotating horizontally, enabling it to be thrown and rotated along the axial direction of the limiting roller, so as to facilitate the chain knife cutting mechanism to cut off the leaf sheaths and enable the straw to be discharged smoothly.

[0015] Preferably, the chain cutter mechanism includes multiple groups of cutting components arranged in parallel. Each cutting component includes a first chain and two hexagonal sprockets. A plurality of tooth cutters and a plurality of blade cutters are installed on the first chain. Above the first frame, there is a first machine frame. The two hexagonal sprockets are rotatably arranged at both ends on the first machine frame and are driven by the first chain. The hexagonal sprockets at the corresponding ends of multiple groups of cutting components are coaxially and fixedly connected. A first motor is installed on the first frame, and the first motor is coaxially and fixedly connected to one of the hexagonal sprockets.

[0016] Furthermore, the tooth cutters and the blade cutters are installed on the first chain at intervals. The length direction of the first chain is perpendicular to the length direction of the limiting roller.

[0017] By adopting the above technical solution, the chain at the upper end of the flexible treatment bag drives the blade cutters and the tooth cutters. The blade cutters are used to cut open the leaf sheath, and the tooth cutters are used to tear the leaf sheath, cutting the side of the straw and removing the leaf sheath of the straw. The removal rate of the leaves and leaf sheaths after treatment exceeds 90%, and the compression recovery rate is lower than 50%. The wettability after treatment is characterized by a contact angle test. The smaller the contact angle, the better the wettability of the straw surface, and the easier it is to fully contact with the water-based adhesive to achieve a better gluing effect. After measuring the contact angle of the straw surface before and after treatment with a contact angle measuring instrument, the average contact angle of the straw decreases by 15° after being treated with this set of devices, and the wetting performance of the straw is improved.

[0018] Preferably, at least two teeth are provided on the tooth cutter, and the tooth tip angle of the teeth is 50° - 70°.

[0019] Preferably, the feeding roller group includes a first rubber roller and a second rubber roller. The fracturing roller group includes a first quadrangular pyramid roller and a second quadrangular pyramid roller. The hair-raising roller group includes a first hair-raising roller and a second hair-raising roller. The densification roller group includes a third rubber roller and a fourth rubber roller. The first rubber roller, the second rubber roller, the third rubber roller, the fourth rubber roller, the first quadrangular pyramid roller, the second quadrangular pyramid roller, the first hair-raising roller, and the second hair-raising roller are all rotatably arranged on the second frame.

[0020] By adopting the above technical solution, the feeding roller group mainly plays the role of pulling in and compressing the raw materials; the main function of the fracturing roller group is to penetrate (increase its permeability) and friction (increase its roughness) the straw surface with the pyramids at a specific angle on the surface, thereby improving its surface wettability and permeability; the main function of the hair-raising roller group is to perform a hair-raising treatment on the straw surface, changing the roughness of the straw and exposing some of the internal tissues of the straw skin; the main function of the densification roller group is for discharging and further compression and shaping treatment;

[0021] By roughening, grinding, and rolling the surface of the straw, the straw core part inside is densified, and the silica layer on the surface is partially damaged, increasing the wettability of the straw surface. The treatment with the quadrangular pyramid rollers opens up the adhesive penetration channels between the surface and the interior of some straws, accelerating the penetration of the adhesive, and providing suitable straw raw materials for the next step of preparing straw parallel overlapping composite materials using conventional urea-formaldehyde resin adhesives.

[0022] Preferably, the rotation speed of the first driving assembly is less than the rotation speed of the second driving assembly.

[0023] By adopting the above technical solution, the surface of the straw is roughened by using the linear speed difference between the surface roughening roller group and other roller groups.

[0024] Further, the first driving assembly includes a second motor, a second chain, and a third chain, and the second driving assembly includes a third motor and a fourth chain;

[0025] Both ends of the first rubber roller are coaxially and fixedly connected with a first sprocket and a second sprocket respectively; both ends of the second rubber roller are fixedly connected with a third sprocket and a fourth sprocket respectively; both ends of the first quadrangular pyramid roller are fixedly connected with a fifth sprocket and a sixth sprocket respectively; both ends of the second quadrangular pyramid roller are fixedly connected with a seventh sprocket and an eighth sprocket respectively; both ends of the first roughening roller are coaxially and fixedly connected with a ninth sprocket and a tenth sprocket respectively; both ends of the second roughening roller are coaxially and fixedly connected with an eleventh sprocket and a twelfth sprocket respectively; both ends of the third rubber roller are fixedly connected with a thirteenth sprocket and a fourteenth sprocket respectively; both ends of the fourth rubber roller are fixedly connected with a fifteenth sprocket and a sixteenth sprocket respectively;

[0026] Among them, the first sprocket, the third sprocket, the fifth sprocket, the seventh sprocket, the ninth sprocket, the eleventh sprocket, the thirteenth sprocket, and the fifteenth sprocket are on one side; the second sprocket, the fourth sprocket, the sixth sprocket, the eighth sprocket, the tenth sprocket, the twelfth sprocket, the fourteenth sprocket, and the sixteenth sprocket are on the other side;

[0027] The second motor is coaxially and fixedly connected with a seventeenth sprocket, and the second chain successively bypasses the seventeenth sprocket, the fifth sprocket, the seventh sprocket, the thirteenth sprocket, and the fifteenth sprocket, and the third chain successively bypasses the second sprocket, the fourth sprocket, and the sixth sprocket;

[0028] The third motor is coaxially and fixedly connected with the eighteenth sprocket, and the fourth chain successively bypasses the eighteenth sprocket, the tenth sprocket, and the twelfth sprocket.

[0029] Preferably, the normal knife angle on the surface of the quadrangular pyramid roller is designed to be 42° - 97°.

[0030] Preferably, the synchronous opening between the upper and lower rollers of the feeding roller group, the wire-brushing roller group, the fracturing roller group and the densifying roller group is set to 5-30 mm.

[0031] The present invention also provides a method for pretreating the raw materials for preparing the straw parallel overlapping composite material by using the above-mentioned straw raw material pretreatment combined device, including the following steps:

[0032] (1) Horizontally feed the straw from the feeding port into the feeding port of the flexible treatment bag;

[0033] (2) Drive the flexible treatment bag and the straw inside the bag to move by friction and tumbling by using the cam assembly, so that the leaves on the surface of the straw fall off;

[0034] (3) When the straw in the flexible treatment bag reaches the full state, the straw overflows from the flexible treatment bag, and the sheath is cut and cut by using the chain knife cutting mechanism, and the straw with the sheath removed is conveyed out;

[0035] (4) Start the first driving assembly to drive the feeding roller group to rotate, and pull the straw in step (3) and perform preliminary compression;

[0036] (5) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed straw, and expose part of the internal tissue of the straw;

[0037] (6) Start the second driving assembly to drive the wire-brushing roller group to rotate, and perform wire-brushing treatment on the surface of the straw in step (5);

[0038] (7) Use the densifying roller group to further compress and shape the wire-brushed straw and discharge it.

[0039] The present invention also provides an application of the straw raw material pretreatment combined device in the preparation of the straw parallel overlapping composite material.

[0040] The present invention also provides a method for preparing the straw parallel overlapping composite material, including the following steps:

[0041] (1) Pretreatment of straw raw materials: Pretreat the straw by using the straw raw material pretreatment combined device to obtain standby straw;

[0042] (2) Preparation of surface veneer: Rotary cut the log to obtain a veneer with a thickness of 0.6 mm to 3.0 mm, and select two veneers to be glued perpendicular to the grain direction to obtain the surface veneer;

[0043] (3) Preparation of core layer material: The core layer is set to an odd number of layers, and the standby straw is selected to be arranged in parallel to form a plane, and the arrangement directions of adjacent two layers of standby straw are perpendicular to each other to obtain the core layer material;

[0044] (4) Preparation of the composite material: Stack the surface veneer and the core layer material layer by layer from the lower layer to the upper layer in the manner of steps (2) and (3), and apply urea-formaldehyde resin adhesive to each layer of raw materials to obtain a board blank;

[0045] (5) Hot-press the board blank into shape to obtain the straw parallel overlapping composite material.

[0046] Preferably, in step (4), the sizing amount of the urea-formaldehyde resin adhesive is 200-300 g / m2.

[0047] Preferably, in step (5), the hot-pressing conditions are: the hot-pressing temperature is 105-145 °C, the hot-pressing pressure is 0.6-1.2 MPa, and the hot-pressing time is 0.9-1.1 min / mm.

[0048] The beneficial effects of the present invention:

[0049] 1. A straw raw material pretreatment combination device provided by the present application can quickly and efficiently process the straw raw materials for the straw parallel overlapping composite material. The processed straw raw materials have characteristics such as a specific shape, high surface energy, high wettability, and high permeability. Moreover, the processing efficiency of this set of devices is high. The production capacity of the leaf and sheath removal device can reach 280 kg per hour (material moisture content ≤ 7%), and the production capacity of the straw surface rolling device can reach 830 kg per hour (material moisture content ≤ 7%).

[0050] 2. The leaf and sheath removal device involved in the present application drives the flexible treatment bag to move by designing a cam assembly, causing the straw raw materials in the flexible treatment bag to have passive throwing-up - falling - friction and other movements, and cutting the leaf sheaths on the straw surface with a toothed knife driven by a chain. Moreover, the movement of the chain drives the materials in the flexible treatment bag to be discharged, realizing the process of removing the leaves and sheaths from the straw; the straw surface rolling device realizes the processes of roughening, polishing, and rolling the straw by designing a four-group roller structure, densifying the inner straw core part and partially destroying the silica layer on the surface.

[0051] 3. The straw raw material pre-treatment assembly device provided in the present application pre-treats crop straw, and assembles and hot-presses the treated straw using the assembly method provided in the present application to prepare straw parallel overlapping composite materials, thereby achieving full utilization of the straw skin and pith, improving the disadvantage that the traditional method of preparing straw boards from straw can only utilize the straw skin, eliminating the step of separating the skin and pith, greatly improving the straw utilization rate, and opening up a new way to use straw as a raw material. Compared with the isocyanate adhesive commonly used in straw artificial boards, this method can use low-cost urea-formaldehyde resin adhesive for gluing through the pre-treatment of straw, thereby reducing costs while ensuring various product properties; the straw parallel overlapping composite materials are prepared by adopting a single-layer parallel and adjacent-layer vertical arrangement, and covering the surface with two layers of wood veneers with overlapping textures. The test is carried out in accordance with the national standard GB / T17657-2013 "Test methods for physical and chemical properties of artificial boards and veneered artificial boards", and meet the following indicators:

[0052] Static bending strength: ≥15MPa

[0053] Elastic modulus: ≥2000MPa

[0054] Surface bonding strength: ≥0.8MPa

[0055] Formaldehyde emission: ≤0.124mg / m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is the front view of the blade and sheath removal device.

[0057] Figure 2 It is a structural diagram showing the connection relationship between the flexible processing mechanism and the cutting component.

[0058] Figure 3 It is a side view of the blade sheath removal device.

[0059] Figure 4 yes Figure 2 Enlarged schematic diagram of part A.

[0060] Figure 5 It is a front view of the straw surface rolling device.

[0061] Figure 6 It is the rear view of the straw surface rolling device.

[0062] Figure 7 It is a side view of the straw surface rolling device.

[0063] Figure 8 is a diagram showing the second chain and the sprocket it passes around.

[0064] Figure 9It is a schematic diagram showing the third chain, the fourth chain and the sprockets they bypass.

[0065] Figure 10 It is a schematic diagram of the blanking of the straw parallel overlapping composite material.

[0066] Figure 11 It is a schematic diagram of the straw parallel overlapping composite material.

[0067] As shown in the figure: 1. The first frame; 2. The flexible treatment mechanism; 21. The flexible treatment bag; 22. The cam assembly; 221. The cam; 222. The cam motor; 3. The chain knife cutting mechanism; 31. The cutting assembly; 311. The first chain; 312. The hexagonal sprocket; 313. The toothed knife; 314. The cutter; 32. The first motor; 4. The viewing window; 5. The limiting roller; 6. The long strip groove; 7. The support roller; 8. The second frame; 9. The roller group mechanism; 91. The feeding roller group; 92. The fracturing roller group; 93. The raising roller group; 94. The densifying roller group; 10. The housing; 111. The first driving assembly; 1111. The second motor; 1112. The second chain; 1113. The third chain; 112. The second driving assembly; 1121. The third motor; 1122. The fourth chain; 12. The lead screw; 13. The mounting plate; 14. The first sprocket; 15. The second sprocket; 16. The third sprocket; 17. The fourth sprocket; 18. The fifth sprocket; 19. The sixth sprocket; 20. The seventh sprocket; 23. The eighth sprocket; 24. The ninth sprocket; 25. The tenth sprocket; 26. The eleventh sprocket; 27. The twelfth sprocket; 28. The thirteenth sprocket; 29. The fourteenth sprocket; 30. The fifteenth sprocket; 33. The sixteenth sprocket; 34. The seventeenth sprocket; 35. The eighteenth sprocket; 36. The tensioning sprocket; 37. The second machine frame; 38. The roller frame. Detailed implementation manners

[0068] Next, the present invention will be further described in conjunction with the drawings.

[0069] Embodiment 1

[0070] As Figures 1-9 shown, the present invention provides a combined device for pre-treating straw raw materials. The combined device for pre-treating straw raw materials includes a leaf sheath removing device and a straw surface rolling device. The leaf sheath removing device is used to remove the leaf sheaths and leaves on the surface of the straw, and the straw surface rolling device is used to perform rolling, friction, acupuncture, raising and other treatments on the surface of the straw.

[0071] Referring to Figure 1 、 2, the leaf and leaf sheath removing device for straw includes a first frame 1, a flexible processing mechanism 2 and a chain knife cutting mechanism 3. The flexible processing mechanism 2 is used to remove the leaves of the straw, and the chain knife cutting mechanism 3 is used to cut off the leaf sheaths of the straw. There is a feeding port between the first frame 1 and the chain knife cutting mechanism 3. An opening is provided on the side wall of the first frame 1. A visible window 4 for opening and closing the opening is rotatably connected to the side wall of the first frame 1. A cavity is provided inside the first frame 1.

[0072] Refer to Figure 2 , 3 , the flexible processing mechanism 2 includes a U-shaped flexible processing bag 21 and a cam assembly 22. The flexible processing bag 21 is arranged inside the cavity. A feeding port is provided above the flexible processing bag 21. The area of the feeding port of the flexible processing bag 21 is larger than the area of the bottom of the flexible processing bag 21. The four corners at the top end of the flexible processing bag 21 are hooked or tied to the side wall of the cavity. A plurality of rectangular holes are provided at the bottom of the flexible processing bag 21. During use, the cut-off leaves and leaf sheaths after processing can fall from the rectangular holes. A limiting roller 5 is fixedly connected between the opposite inner walls of the first frame 1. The limiting roller 5 penetrates through the flexible processing bag 21 and is located in the upper middle part of the flexible processing bag 21.

[0073] Two upper and lower parallel long strip-shaped grooves 6 are provided on the opposite inner walls of the first frame 1. The long strip-shaped grooves 6 are arranged at the discharge end. A support roller 7 for supporting the flexible processing bag 21 is slidably connected in the long strip-shaped grooves 6. The purpose of providing two long strip-shaped grooves 6 is to provide two working positions. When a large discharge amount of materials and a long netting cycle of materials are required, the high position can be selected, and vice versa, the low position can be selected.

[0074] Refer to Figure 2 , 3 , the cam assembly 22 is arranged below the flexible processing bag 21 and is used to drive the movement of the flexible processing bag 21 and the straw inside the bag; the cam assembly 22 includes a plurality of cams 221 and a cam motor 222. In this embodiment, the number of cams 221 is set to five. The five cams 221 are coaxially fixedly connected and are all rotatably connected inside the cavity. The cam motor 222 is installed on the outer wall of the first frame 1 through bolts. The output shaft of the cam motor 222 is coaxially fixedly connected to the five cams 221.

[0075] The chain knife cutting mechanism 3 includes a plurality of groups of cutting assemblies 31 arranged in parallel and a first motor 32. In this embodiment, the number of cutting assemblies 31 is set to five groups.

[0076] Refer to Figure 2 , 4, a set of cutting components 31 includes a first chain 311, two hexagonal sprockets 312, a toothed knife 313 and a cutting knife 314 mounted on the first chain 311; a first frame 1 is provided with a first machine frame above it, and the two hexagonal sprockets 312 are rotatably arranged at both ends on the first machine frame and are driven by the first chain 311; the hexagonal sprockets 312 at the corresponding ends of multiple sets of cutting components 31 are coaxially fixedly connected, the first motor 32 is mounted on the first frame 1 by bolts, and the first motor 32 is coaxially fixedly connected to one of the hexagonal sprockets 312. The length direction of the first chain 311 is perpendicular to the length direction of the limiting roller 5. During use, the first chain 311 can be set with a certain hanging amount according to actual needs. A gap for the straw to pass through is left between the first frame 1 and the first chain 311.

[0077] Refer to Figure 2 , 4 , the toothed knife 313 and the cutting knife 314 are installed at intervals on the first chain 311, at least two teeth are provided on the toothed knife 313, and the tooth tip angle of the toothed knife 313 is 50° - 70°. The complete first chain 311, toothed knife 313 and cutting knife 314 are not shown in the drawings.

[0078] Refer to Figure 5 , 6 , the straw surface rolling device includes a second frame 8, a roller group mechanism 9 and a housing 10, the roller group mechanism 9 is arranged on the second frame 8, and the housing 10 covers the roller group mechanism 9.

[0079] The roller group mechanism 9 includes a feeding roller group 91, a fracturing roller group 92, a hair-raising roller group 93 and a densifying roller group 94 arranged in parallel side by side in sequence. The hair-raising roller group 93 is driven asynchronously with the feeding roller group 91, the fracturing roller group 92 and the densifying roller group 94. A driving mechanism for driving the feeding roller group 91, the fracturing roller group 92, the hair-raising roller group 93 and the densifying roller group 94 to rotate is also arranged on the second frame 8.

[0080] The feeding roller group 91 includes a first rubber roller and a second rubber roller, the fracturing roller group 92 includes a first quadrangular pyramid roller and a second quadrangular pyramid roller, the hair-raising roller group 93 includes a first hair-raising roller and a second hair-raising roller, and the densifying roller group 94 includes a third rubber roller and a fourth rubber roller. A second machine frame 37 is fixedly connected to the second frame 8, and the second rubber roller, the second quadrangular pyramid roller, the second hair-raising roller and the fourth rubber roller are rotatably connected to the second machine frame 37. The surface of the quadrangular pyramid roller is designed with a normal knife angle of 42° - 97°. The synchronous opening between the upper and lower rollers of the feeding roller group 91, the hair-raising roller group 93, the fracturing roller group 92 and the densifying roller group 94 is set to 5 - 30 mm.

[0081] Refer to Figures 5-9, both ends of the first rubber roller, the first square pyramid roller, the first hair-raising roller and the third rubber roller are rotatably connected to mounting plates 13. A roller frame 38 is fixedly connected to the second frame 8. Eight lead screws 12 are threadedly connected to the roller frame 38, and the eight lead screws 12 correspond to the eight mounting plates 13 one by one. The mounting plate 13 can be displaced under the traction of the lead screw 12 to adjust the opening degree of the upper and lower roller groups.

[0082] The driving mechanism includes a first driving component 111 and a second driving component 112. The second driving component 112 is used to drive the rotation of the hair-raising roller group 93, and the first driving component 111 is used to drive the rotation of the feeding roller group 91, the fracturing roller group 92 and the densifying roller group 94. The rotation speed of the first driving component 111 is lower than that of the second driving component 112.

[0083] The first driving component 111 includes a second motor 1111, a second chain 1112 and a third chain 1113, and the second driving component 112 includes a third motor 1121 and a fourth chain 1122.

[0084] Both ends of the first rubber roller are coaxially and fixedly connected with a first sprocket 14 and a second sprocket 15 respectively; both ends of the second rubber roller are fixedly connected with a third sprocket 16 and a fourth sprocket 17 respectively; both ends of the first square pyramid roller are fixedly connected with a fifth sprocket 18 and a sixth sprocket 19 respectively; both ends of the second square pyramid roller are fixedly connected with a seventh sprocket 20 and an eighth sprocket 23 respectively; both ends of the first hair-raising roller are coaxially and fixedly connected with a ninth sprocket 24 and a tenth sprocket 25 respectively; both ends of the second hair-raising roller are coaxially and fixedly connected with an eleventh sprocket 26 and a twelfth sprocket 27 respectively; both ends of the third rubber roller are fixedly connected with a thirteenth sprocket 28 and a fourteenth sprocket 29 respectively; both ends of the fourth rubber roller are fixedly connected with a fifteenth sprocket 30 and a sixteenth sprocket 33 respectively;

[0085] Among them, the first sprocket 14, the third sprocket 16, the fifth sprocket 18, the seventh sprocket 20, the ninth sprocket 24, the eleventh sprocket 26, the thirteenth sprocket 28 and the fifteenth sprocket 30 are located on one side; the second sprocket 15, the fourth sprocket 17, the sixth sprocket 19, the eighth sprocket 23, the tenth sprocket 25, the twelfth sprocket 27, the fourteenth sprocket 29 and the sixteenth sprocket 33 are located on the other side.

[0086] A seventeenth sprocket 34 is coaxially and fixedly connected to the second motor 1111. The second chain 1112 successively bypasses the seventeenth sprocket 34, the fifth sprocket 18, the seventh sprocket 20, the thirteenth sprocket 28, and the fifteenth sprocket 30. The third chain 1113 successively bypasses the second sprocket 15, the fourth sprocket 17, and the sixth sprocket 19. An eighteenth sprocket 35 is coaxially and fixedly connected to the third motor 1121. The fourth chain 1122 successively bypasses the eighteenth sprocket 35, the tenth sprocket 25, and the twelfth sprocket 27. To improve the transmission performance of the second chain 1112, the third chain 1113, and the fourth chain 1122, tensioning sprockets 36 corresponding to the second chain 1112, the third chain 1113, and the fourth chain 1122 are provided on the opposite side walls of the second frame 8. The tensioning sprockets 36 press against the second chain 1112, the third chain 1113, and the fourth chain 1122, thereby realizing the tensioning of the second chain 1112, the third chain 1113, and the fourth chain 1122. The tensioning sprockets 36 are prior art and will not be elaborated here. In actual use, the number of tensioning sprockets 36 can be set according to actual needs.

[0087] Example 2: Pretreatment method for raw materials of corn straw parallel overlapping composite

[0088] (1) Horizontally feed the corn straw from the feeding port into the feeding port of the flexible treatment bag;

[0089] (2) Start the cam motor. The cam motor drives the cam to rotate, and the cam drives the flexible treatment bag and the corn straw inside the bag to perform frictional rolling motion, so that the leaves on the surface of the corn straw fall off;

[0090] (3) When the corn straw in the flexible treatment bag reaches a full state, the straw overflows from the flexible treatment bag. Start the first motor, use the tooth knives and cutters on the chain to cut and cut the leaf sheaths, and convey the corn straw with the leaf sheaths removed out of the discharge end of the leaf sheath removing device;

[0091] (4) Start the second motor. The second motor drives the feeding roller group to rotate, thereby pulling the corn straw in step (3) in and performing preliminary compression;

[0092] (5) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed corn straw, and expose part of the internal tissue of the corn straw;

[0093] (6) Start the third motor. The third motor drives the brushing roller group to perform brushing treatment on the surface of the corn straw in step (5);

[0094] (7) Use the densifying roller group to further compress and shape the brushed corn straw and discharge it.

[0095] Example 3: Preparation of corn straw parallel overlapping composite

[0096] (1)Pretreatment of corn straw raw material: The treatment method here is the same as that in Example 2.

[0097] (2)Preparation of surface veneer: The surface veneer is made of birch veneer with a thickness of 1.2 mm obtained by rotary cutting logs. The length and width dimensions are 430 mm × 430 mm, and the moisture content is 8%. Two birch veneers are used for the upper and lower surfaces respectively, and the textures are laid perpendicular to each other.

[0098] (3)Preparation of core layer material: The corn straw treated in (1) is used, cut into raw materials with a length of 430 mm, and laid parallel on the birch veneer. The laying amount per layer is 10 pieces. The laying direction of the second layer of corn straw is perpendicular to the first layer, and the laying direction of the third layer of corn straw is perpendicular to the second layer. The moisture content of the corn straw is 7%.

[0099] (4)Preparation of composite material: Urea-formaldehyde resin adhesive is selected, with a solid content of 55% and a viscosity of 200 mPa·s. The glue is applied layer by layer to each layer of the board blank by the gluing method, and the gluing amount is 250 g / m 2 (double-sided). According to steps (2) and (3), the surface veneer and the core layer material are assembled to obtain a board blank.

[0100] (5)Hot pressing treatment: The board blank is hot pressed at a hot pressing temperature of 105 °C and a hot pressing pressure of 1.0 MPa for 4 minutes to obtain a corn straw parallel overlapping composite material. The density of the board is 0.8 g / cm 3 .

[0101] Testing: The obtained corn straw parallel overlapping composite material is subjected to physical and chemical property testing and formaldehyde release amount testing in accordance with the national standard GB / T17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels". The test results are shown in Table 1.

[0102] Comparative Example 1

[0103] Preparation of corn straw parallel overlapping composite material

[0104] (1)Pretreatment of corn straw raw material: (Compared with Example 3, there is no treatment with a leaf sheath removal device)

[0105] 1) Start the second motor, and the second motor drives the feeding roller group to rotate, pulling in the corn straw and performing preliminary compression;

[0106] 2) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed corn straw, and expose part of the internal tissue of the corn straw;

[0107] 3) Start the third motor, and the third motor drives the brushing roller group to perform brushing treatment on the surface of the corn straw in step 2);

[0108] 4) Use the densification roller group to further compress and shape the corn straw after the roughening treatment and discharge the material.

[0109] (2) Preparation of the surface veneer: The surface uses a birch veneer with a thickness of 1.2 mm obtained by rotary cutting logs. The length and width dimensions are 430 mm × 430 mm, and the moisture content is 8%. Two birch veneers are used for the upper and lower surfaces respectively, and the textures are laid perpendicular to each other.

[0110] (3) Preparation of the core layer material: Use the corn straw treated in step (1), cut it into raw materials with a length of 430 mm, lay it parallel on the birch veneer, with 10 pieces laid per layer. The laying direction of the second layer of corn straw is perpendicular to the first layer, and the laying direction of the third layer of corn straw is perpendicular to the second layer. The moisture content of the corn straw is 7%.

[0111] (4) Preparation of the composite material: Select urea-formaldehyde resin adhesive with a solid content of 55% and a viscosity of 200 mPa·s. Use the gluing method to glue each layer of the board blank layer by layer, and the gluing amount is 250 g / m 2 (both sides), and assemble the surface veneer and the core layer material according to steps (2) and (3) to obtain a board blank.

[0112] (5) Hot pressing treatment: Hot press the board blank at a hot pressing temperature of 105 °C and a hot pressing pressure of 1.0 MPa for 4 minutes to obtain a corn straw parallel overlapping composite material. The density of the board is 0.8 g / cm 3 .

[0113] Detection: Conduct physical and chemical property detection and formaldehyde release amount detection on the obtained corn straw parallel overlapping composite material according to the national standard GB / T17657-2013 "Test Methods for Physical and Chemical Properties of Wood-Based Panels and Decorative Wood-Based Panels". The detection results are shown in Table 1.

[0114] Comparative Example 2

[0115] Preparation of corn straw parallel overlapping composite material (compared with Example 3, without the treatment of the flexible treatment mechanism)

[0116] (1) Pretreatment of corn straw raw materials:

[0117] 1) Start the first motor, use the toothed knife and cutter on the chain to cut open and cut the leaf sheath, and convey the corn straw with the leaf sheath removed to discharge from the discharge end of the leaf sheath removing device for the leaves;

[0118] 2) Start the second motor, and the second motor drives the feeding roller group to rotate, so as to pull the corn straw in step 1) and conduct preliminary compression;

[0119] 3) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed corn straw, and expose part of the internal tissue of the corn straw;

[0120] 4) Start the third motor, and the third motor drives the burr roller group to burr the surface of the corn straw in step 3).

[0121] 5) Use the densification roller group to further compress and shape the burr-treated corn straw and discharge it.

[0122] (2) Preparation of surface veneer: The surface layer uses a birch veneer with a thickness of 1.2 mm obtained by rotary cutting logs. The length and width dimensions are 430 mm × 430 mm, and the moisture content is 8%. Two birch veneers are used for the upper and lower surface layers respectively, and the textures are laid perpendicular to each other.

[0123] (3) Preparation of core layer material: Use the corn straw treated in step (1), cut it into raw materials with a length of 430 mm, lay it parallel on the birch veneer, with 10 pieces laid per layer. The laying direction of the second layer of corn straw is perpendicular to the first layer, and the laying direction of the third layer of corn straw is perpendicular to the second layer. The moisture content of the corn straw is 7%.

[0124] (4) Preparation of composite material: Select urea-formaldehyde resin adhesive with a solid content of 55% and a viscosity of 200 mPa·s. Adhere to each layer of board blank layer by layer by the gluing method, and the gluing amount is 250 g / m 2 (double-sided). Group the surface veneer and the core layer material according to steps (2) and (3) to obtain a board blank.

[0125] (5) Hot pressing treatment: Hot press the board blank at a hot pressing temperature of 105 °C and a hot pressing pressure of 1.0 MPa for 4 min to obtain a parallel overlapping composite material of corn straw. The density of the board is 0.8 g / cm 3 .

[0126] Detection: Carry out physical and chemical property detection and formaldehyde release amount detection on the prepared parallel overlapping composite material of corn straw according to the national standard GB / T17657-2013 "Test Methods for Physical and Chemical Properties of Wood-Based Panels and Decorative Wood-Based Panels". The detection results are shown in Table 1.

[0127] Comparative Example 3

[0128] Preparation of parallel overlapping composite material of corn straw (compared with Example 3, without the treatment of the fracturing roller group)

[0129] (1) Pretreatment of corn straw raw materials:

[0130] 1) Horizontally feed the corn straw from the feeding port into the feeding port of the flexible treatment bag;

[0131] 2) Start the cam motor, the cam motor drives the cam to rotate, and the cam drives the flexible treatment bag and the corn straw in the bag to move in a frictional rolling motion, so that the leaves on the surface of the corn straw fall off;

[0132] 3) When the corn straw in the flexible treatment bag reaches the full state, the straw overflows from the flexible treatment bag, the first motor is started, and the toothed knives and cutters on the chain are used to cut and cut the leaf sheath, and the corn straw with the leaf sheath removed is conveyed and discharged from the discharge end of the leaf sheath removing device for the blade;

[0133] 4) Start the second motor, and the second motor drives the feeding roller group to rotate, so as to pull the corn straw in step 3) and perform preliminary compression;

[0134] 5) Start the third motor, and the third motor drives the napping roller group to perform napping treatment on the surface of the corn straw in step 4);

[0135] 6) Use the densification roller group to further compress and shape the napped corn straw and discharge it.

[0136] (2) Preparation of surface veneer: The surface layer uses a birch veneer with a thickness of 1.2 mm obtained by rotary cutting logs. The length and width dimensions are 430 mm × 430 mm, and the moisture content is 8%. Two birch veneers are used for the upper and lower surface layers respectively, and the textures are laid perpendicular to each other.

[0137] (3) Preparation of core layer material: Use the corn straw treated in (1), cut it into raw materials with a length of 430 mm, lay it parallel on the birch veneer, the laying amount per layer is 10 roots, the laying direction of the second layer of corn straw is perpendicular to the first layer, and the laying direction of the third layer of corn straw is perpendicular to the second layer. The moisture content of the corn straw is 7%.

[0138] (4) Preparation of composite material: Select urea-formaldehyde resin adhesive with a solid content of 55% and a viscosity of 200 mPa·s, and use the gluing method to glue each layer of the board blank layer by layer. The gluing amount is 250 g / m 2 (double-sided), according to step (2) and step (3), assemble the surface veneer and the core layer material to obtain a board blank.

[0139] (5) Hot pressing treatment: Hot press the board blank at a hot pressing temperature of 105 °C and a hot pressing pressure of 1.0 MPa for 4 min to obtain a corn straw parallel overlapping composite material. The density of the board is 0.8 g / cm 3 .

[0140] Detection: The prepared corn straw parallel overlapping composite material is subjected to physical and chemical property detection and formaldehyde release amount detection according to the national standard GB / T17657-2013 "Test Methods for Physical and Chemical Properties of Wood-Based Panels and Decorative Wood-Based Panels". The detection results are shown in Table 1.

[0141] Comparative Example 4

[0142] Preparation of corn straw parallel overlapping composite material (compared with Example 3, without napping roller group treatment)

[0143] (1)Pretreatment of corn straw raw material:

[0144] 1) Horizontally feed the corn straw into the feed inlet of the flexible treatment bag from the feeding port;

[0145] 2) Start the cam motor, the cam motor drives the cam to rotate, and the cam drives the flexible treatment bag and the corn straw inside the bag to move by friction and tumbling, so that the leaves on the surface of the corn straw fall off;

[0146] 3) When the corn straw in the flexible treatment bag reaches a full state, the straw overflows from the flexible treatment bag, start the first motor, use the toothed knife and cutter on the chain to cut and cut the leaf sheath, and convey the corn straw with the leaf sheath removed to discharge from the discharge end of the leaf and leaf sheath removal device;

[0147] 4) Start the second motor, the second motor drives the feeding roller group to rotate, so as to pull the corn straw in step 3) and conduct preliminary compression;

[0148] 5) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed corn straw, and expose part of the internal tissue of the corn straw;

[0149] 6) Use the densification roller group to further compress and shape the corn straw in step 5) and discharge it.

[0150] (2)Preparation of surface veneer: The surface layer uses a birch veneer with a thickness of 1.2 mm obtained by rotary cutting of logs. The length and width dimensions are 430 mm × 430 mm, and the moisture content is 8%. Two birch veneers are used for the upper and lower surface layers respectively, and the textures are laid perpendicular to each other.

[0151] (3)Preparation of core layer material: Use the corn straw treated in (1), cut it into raw materials with a length of 430 mm, lay it parallel on the birch veneer, the laying amount per layer is 10 pieces, the laying direction of the second layer of corn straw is perpendicular to the first layer, and the laying direction of the third layer of corn straw is perpendicular to the second layer. The moisture content of the corn straw is 7%.

[0152] (4)Preparation of composite material: Select urea-formaldehyde resin adhesive with a solid content of 55% and a viscosity of 200 mPa·s, and use the gluing method to glue each layer of the board blank layer by layer, and the gluing amount is 250 g / m 2 (double-sided), according to step (2) and step (3), assemble the surface veneer and the core layer material to obtain a board blank.

[0153] (5)Hot pressing treatment: Hot press the board blank at a hot pressing temperature of 105 °C and a hot pressing pressure of 1.0 MPa for 4 min to obtain a corn straw parallel overlapping composite material. The density of the board is 0.8 g / cm 3 .

[0154] Testing: The physical and chemical properties and formaldehyde release of the prepared corn straw parallel overlapping composite materials were tested in accordance with the national standard GB / T 17657-2013 "Test Methods for Physical and Chemical Properties of Wood-based Panels and Decorative Wood-based Panels". The test results are shown in Table 1.

[0155] Table 1

[0156]

[0157] The physical and chemical property indexes of the corn straw parallel overlapping composite materials prepared in Example 3 meet the requirements of GB / T 21723-2021 "Wheat (Rice) Straw Particleboard", and the formaldehyde release meets the requirements of GB 18580-2017 "Limit of Formaldehyde Release in Interior Decoration Materials - Wood-based Panels and Their Products", and can be used for interior decoration materials, furniture materials and wall insulation materials.

[0158] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A pretreatment combination device for straw raw materials, characterized in that, It includes a leaf and sheath removing device and a straw surface rolling device. The leaf and sheath removing device includes a first frame. A cavity is formed inside the first frame. A U-shaped flexible treatment bag is arranged inside the cavity. A feed inlet is formed above the flexible treatment bag. A cam assembly is arranged below the flexible treatment bag for driving the movement of the flexible treatment bag and the straw inside the bag. A chain knife cutting mechanism is arranged above the first frame. A feeding port is arranged between the first frame and the chain knife cutting mechanism. The straw surface rolling device includes a second frame. A feeding roller group, a fracturing roller group, a hair-raising roller group and a densifying roller group are arranged in parallel and side by side on the second frame. The feeding roller group, the fracturing roller group and the densifying roller group are driven to rotate by a first driving component. The hair-raising roller group is driven to rotate by a second driving component.

2. The pretreatment combination device for straw raw materials according to claim 1, wherein A plurality of rectangular holes are formed at the bottom of the flexible treatment bag.

3. The pretreatment combination device for straw raw materials according to claim 2, wherein An opening is formed on the side wall of the first frame. A visual window for opening and closing the opening is rotatably connected to the side wall of the first frame.

4. The pretreatment combination device for straw raw materials according to claim 1 or 3, characterized in that A limiting roller is arranged between the opposite inner walls of the first frame. The limiting roller penetrates through the flexible treatment bag and is located in the upper middle part of the flexible treatment bag.

5. The pretreatment combination device for straw raw materials according to claim 4, wherein, The chain knife cutting mechanism includes a plurality of groups of cutting components arranged in parallel. Each cutting component includes a first chain and two hexagonal sprockets. The two hexagonal sprockets are rotatably arranged on the first frame and are driven by the first chain. A plurality of toothed knives and a plurality of cutting knives are installed on the first chain. The length direction of the first chain is perpendicular to the length direction of the limiting roller.

6. The pretreatment combination device for straw raw materials according to claim 1, characterized in that, The rotation speed of the first driving component is less than the rotation speed of the second driving component.

7. A method for pretreating the raw materials for preparing straw parallel overlapping composite materials by using the straw raw material pretreatment combination device according to any one of claims 1-6, characterized in that, It includes the following steps: (1) Horizontally feed the straw into the feed inlet of the flexible treatment bag from the feeding port. (2) Use the cam assembly to drive the flexible treatment bag and the straw inside the bag to move by friction and tumbling, so that the leaves on the surface of the straw fall off. (3) When the straw in the flexible treatment bag reaches a full state, the straw overflows from the flexible treatment bag. Use the chain knife cutting mechanism to cut and separate the leaf sheaths, and convey the straw with the leaf sheaths removed out of the machine. (4) Start the first driving component to drive the feeding roller group to rotate, and pull the straw in step (3) in and perform preliminary compression. (5) Use the fracturing roller group to pierce and rub the surface of the preliminarily compressed straw, and expose part of the internal tissue of the straw. (6) Start the second driving component to drive the hair-raising roller group to rotate, and perform hair-raising treatment on the surface of the straw in step (5). (7) Use the densifying roller group to further compress and shape the hair-raised straw and discharge it.

8. Application of the straw raw material pretreatment combined device according to any one of claims 1-6 in the preparation of straw parallel overlapping composite materials.

9. A method for preparing straw parallel overlapping composite materials, characterized in that, It includes the following steps: (1) Pretreatment of straw raw materials: Pretreat the straw by using the method described in claim 7 to obtain standby straw. (2) Preparation of surface veneer: Rotary cut logs to obtain veneers with a thickness of 0.6 mm to 3.0 mm. Select two veneers and glue them perpendicular to the grain direction to obtain the surface veneer. (3) Preparation of core layer material: The core layer is set to an odd number of layers. Select standby straw and arrange them in parallel to form a plane. The arrangement directions of adjacent two layers of standby straw are perpendicular to each other to obtain the core layer material. (4) Preparation of the composite material: Stack the surface veneer and the core layer material layer by layer from the lower layer to the upper layer in the manner of steps (2) and (3), and apply urea-formaldehyde resin adhesive to each layer of raw materials to obtain a board blank; (5) Hot-press the board blank into shape to obtain the straw parallel overlapping composite material.

10. The method according to claim 9, characterized in that, In step (4), the sizing amount of the urea-formaldehyde resin adhesive is 200-300 g / m 2 .

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