Unfolded bamboo multilayer board and preparation method therefor

Abstract

The present invention relates to the technical field of bamboo processing. Disclosed are an unfolded bamboo multilayer board and a preparation method therefor. The unfolded bamboo multilayer board comprises at least two bamboo sheet layers which are stacked, wherein each bamboo sheet layer comprises at least two bamboo sheets joined to each other, bamboo fiber directions of the bamboo sheets of every two adjacent bamboo sheet layers intersect each other, and the density difference between the bamboo sheets of the same layer is less than or equal to 200 kg / m3. The preparation method comprises firstly manufacturing an unfolded bamboo board into bamboo sheets and then laminating the bamboo sheets after joining and widening same. The unfolded bamboo multilayer board provided in the present invention has stable physical properties, is less prone to deformation even if the width is increased, achieves high production efficiency, and is also more environmentally friendly.

Description

Bamboo expanded multi-layer board and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of bamboo processing, and particularly relates to a bamboo expanded multi-layer board and a preparation method thereof. BACKGROUND

[0002] Traditional bamboo flat-pressed composite boards are prone to deformation when the size increases due to the unique fiber direction and uneven density distribution of bamboo. The larger the size, the more serious the deformation. When the same direction of the board is affected by dry or humid environment, it will also cause inconsistent dry shrinkage or expansion rate, resulting in cracking and unable to realize the production of large size specifications. The application of bamboo is restricted. Although there are some large size bamboo composite boards on the market, these bamboo composite boards (bamboo multi-layer boards) mostly use small size raw materials for splicing, and the width of the raw materials is about 10-30 mm, or the raw materials are vertically arranged for splicing. For example, a bamboo laminated board disclosed in Chinese Patent No. CN2361726Y uses a vertical arrangement. If the above splicing method is used to realize the production of large size specifications, a large amount of glue will be used in the preparation process, which does not meet the characteristics of sustainable and renewable bamboo. TECHNICAL PROBLEM

[0003] In order to overcome the defects of the above-mentioned prior art, the technical problem to be solved by the present application is to provide a bamboo expanded multi-layer board which can use wide raw materials and uses less glue, and a preparation method thereof. TECHNICAL SOLUTION

[0004] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a bamboo expanded multi-layer board comprises at least two laminated bamboo sheet layers, each bamboo sheet layer comprises at least two bamboo sheets spliced with each other, the bamboo fiber directions of the bamboo sheets of adjacent two bamboo sheet layers intersect, and the density difference between the bamboo sheets in the same layer is ≤200 kg / m 3 .

[0005] A preparation method of the above-mentioned bamboo expanded multi-layer board comprises the following steps: first, bamboo expanded boards are made into bamboo sheets; then, the bamboo sheet layers obtained by splicing the bamboo sheets are laminated. ADVANTAGEOUS EFFECTS

[0006] The beneficial effects of the present application are that: the bamboo pieces made of bamboo expansion boards are spliced to form a multi-layer board by screening bamboo pieces with close density, which overcomes the poor structural stability caused by the strength difference and uneven density distribution of bamboo itself, and the problem of easy deformation of the multi-layer board. Further, the environmentally friendly multi-layer board with a larger width and not easy to deform can be prepared under the premise of using less glue. The bamboo fibers of the bamboo pieces of the adjacent two layers intersect, so that the bamboo pieces in one layer of the adjacent two layers will not crack due to dry shrinkage or expansion under the protection of the high tensile strength of the bamboo fibers in the other layer, and the composite bamboo material with better and more uniform physical properties is obtained. At the same time, the width of the spliced width can be increased, and the bamboo multi-layer board with a larger width and not easy to deform can be prepared, which can greatly reduce the use of glue and obtain a more environmentally friendly composite bamboo material. BRIEF DESCRIPTION OF DRAWINGS

[0007] Fig. 1 is a schematic diagram of the exploded structure of the bamboo expansion multi-layer board of the embodiment of the present application;

[0008] Fig. 2 is a schematic diagram of the partial exploded structure of the bamboo expansion multi-layer board of the embodiment of the present application;

[0009] Fig. 3 is a schematic diagram of the exploded structure of the bamboo expansion multi-layer board of the embodiment of the present application;

[0010] Fig. 4 is a schematic diagram of the partial exploded structure of the bamboo expansion multi-layer board of the embodiment of the present application. Embodiments of the present application

[0011] To explain the technical content, purposes and effects of the present application in detail, the following embodiments are described with reference to the accompanying drawings.

[0012] The bamboo expansion multi-layer board of the present application comprises at least two layers of bamboo pieces stacked, wherein the bamboo piece layer comprises at least two spliced bamboo pieces, the bamboo fibers of the bamboo pieces of the adjacent two layers intersect, and the density difference between the bamboo pieces in the same layer is ≤200 kg / m 3 .

[0013] The splicing method can be butt joint or other commonly used splicing method in the bamboo field. The splicing can be length splicing along the direction of the bamboo fibers, or width splicing along the direction perpendicular to the bamboo fibers, and in most cases, width splicing is performed.

[0014] As can be seen from the above description, the beneficial effects of the present application are that: the bamboo pieces made of bamboo expansion boards can be obtained by planing, rotary cutting, etc., and the density difference of the obtained bamboo pieces is smaller than that of the bamboo expansion boards. By screening the bamboo pieces with close density and then compounding to form a multi-layer board, the problem of easy deformation of the multi-layer board due to size increase can be avoided, and a bamboo multi-layer board with a larger width and not easy to deform can be prepared, thereby expanding the application field of the bamboo multi-layer board.

[0015] In one or more embodiments, the density difference between different bamboo pieces between layers is ≤200 kg / m 3 . By further controlling the density of the bamboo pieces between layers, the density difference of the bamboo pieces used in the same multi-layer board is within 200 kg / m 3 , such as a density difference of 200 kg / m 3 , 190 kg / m 3 , 180 kg / m 3 , 170 kg / m 3 , 160 kg / m 3 , 150 kg / m 3 , 140 kg / m 3 , 130 kg / m 3 , 120 kg / m 3 , 110 kg / m 3 , 100 kg / m 3 , 90 kg / m 3 , 80 kg / m 3 , 70 kg / m 3 , 60 kg / m 3 , 50 kg / m 3 , 40 kg / m 3 , 30 kg / m 3 , 20 kg / m 3 , etc. This can effectively avoid the different shrinkage and expansion rates caused by different densities, which can easily cause tile-shaped deformation.

[0016] In one or more embodiments, the thickness of the bamboo pieces is 0.5-4 mm, such as 0.5-3 mm, or 2-3 mm. The bamboo pieces with the above thickness are different from the thicker bamboo boards commonly used to make multi-layer bamboo boards, which have a smaller density difference within a single layer and a more uniform density, and are less likely to deform after being made into multi-layer bamboo boards. The appropriate thickness can be selected based on the material properties and processing difficulty.

[0017] In one or more embodiments, the width of the bamboo pieces is ≥50 mm, such as 50-200 mm. The width of the single-piece raw material used to make multi-layer bamboo boards on the market is mostly below 30 mm, and the width of the multi-layer boards made is also relatively small, such as bamboo flooring. By reducing the thickness of the single layer of the bamboo expansion board, reducing the density difference, and increasing the width, a wide-width bamboo expansion multi-layer board with stable performance and less deformation can be prepared. Using wide-width bamboo pieces for processing can significantly improve the processing efficiency. That is, since the density of the bamboo pieces is screened, the density difference between the bamboo pieces is small, and the width can be increased during use. Even if wide-width bamboo pieces are used as raw materials for preparation, a wide-width bamboo expansion multi-layer board with stable performance and less deformation can be obtained.

[0018] In one or more embodiments, the length of the bamboo pieces is 1-4 m, such as 1.5-2.5 m. The length of the bamboo pieces can be selected according to the length of the raw material and the specifications of the final product, and the bamboo pieces can be cut to length.

[0019] In one or more embodiments, the bamboo fiber directions of the bamboo pieces in the same layer are parallel to each other. The bamboo fiber directions of the bamboo pieces in the same layer being parallel to each other facilitates the width expansion.

[0020] In one or more embodiments, the bamboo fiber directions of the bamboo pieces in adjacent two layers are perpendicular to each other. The bamboo fiber directions of the bamboo pieces in the same layer being parallel to each other facilitates the width expansion. The bamboo fiber directions of the bamboo pieces in adjacent two layers are preferably not parallel to each other but intersecting, i.e., at an angle, which can be 90°, i.e., the bamboo fiber directions of the bamboo pieces in adjacent two layers are perpendicular to each other, so that when the whole board is in a dry or humid environment, the physical properties and stability of the whole board after compounding are improved at this angle (90°).

[0021] In one or more embodiments, an adhesive layer is provided between the bamboo piece layers. The adhesive layer is composed of glue and is used to bond (fit) the upper and lower bamboo piece layers.

[0022] In one or more embodiments, the number of bamboo piece layers is odd.

[0023] In one or more embodiments, the bamboo fiber directions of the bamboo pieces in the uppermost layer and the lowermost layer are the same.

[0024] The odd number of layers can make the bamboo fiber directions of the bamboo pieces in the uppermost layer and the lowermost layer consistent, and thus the specifications of the multi-layer board made are more uniform.

[0025] In one or more embodiments, the method for preparing a bamboo expanded multi-layer board comprises the following steps: first, planing or rotary cutting the bamboo expanded board into bamboo pieces; then, expanding the width of the bamboo pieces and laminating the bamboo pieces;

[0026] The number of laminations is at least two; the bamboo fiber directions of the bamboo pieces in adjacent two layers intersect, and the density difference between the bamboo pieces in the same layer is ≤200 kg / m 3 .

[0027] The width expansion method can be splicing or other commonly used bamboo piece splicing methods.

[0028] The bamboo expansion multi-layer board manufacturing method does not directly use bamboo expansion board lamination (stacking) to manufacture bamboo expansion multi-layer board, but first uses planing or rotary cutting to manufacture bamboo pieces with thinner thickness, and then lamination (stacking) is performed on the bamboo pieces to manufacture bamboo expansion multi-layer board according to the density difference screening, so that the deformation problem caused by the too large density difference of the bamboo expansion board can be reduced, and the multi-layer board with larger width and less deformation can be obtained. Since the width connection is performed in the form of splicing in the single layer, the amount of glue used can be significantly reduced, and a more environmentally friendly multi-layer board can be obtained.

[0029] In one or more embodiments, the step of gluing and drying is further included between splicing and lamination. After gluing, low-temperature drying of 40-80°C is performed first, and then multi-layer pressing is performed.

[0030] In one or more embodiments, the temperature for lamination is 70-180°C. The temperature for lamination is mainly set according to the adhesive. According to the commonly used adhesive for bamboo composite materials, the temperature for lamination is set to 70-180°C. The temperature for lamination can also be changed according to the specific situation of the new adhesive.

[0031] In one or more embodiments, the moisture content of the bamboo pieces is below 15%, such as 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, etc. The moisture content should not be too high.

[0032] In at least one embodiment, the bamboo expansion multi-layer board manufacturing method comprises the following steps:

[0033] S1. First, planing or rotary cutting the bamboo expansion board with a width of 50 mm and a length of 1 m into bamboo pieces with a thickness of 2 mm;

[0034] S2. Control the moisture content of the bamboo pieces to be 15%, and then detect the density of the bamboo pieces; according to the density of the bamboo pieces, select the bamboo pieces with a density difference of 50 kg / m 3 for splicing in the direction perpendicular to the fiber direction; the fiber directions of the bamboo pieces in the same layer during splicing are the same (parallel to each other), and 6 single-layer bamboo materials are obtained; the single-layer bamboo material is the bamboo piece layer;

[0035] S3. After gluing on one side of the 6 single-layer bamboo materials, drying is performed, and then stacking and hot pressing are performed, and the temperature for hot pressing is 120°C; during stacking, the bamboo fiber directions of the adjacent two layers of bamboo pieces are perpendicular to each other (i.e., 90°);

[0036] S4. The multi-layer board after hot pressing is rapidly cooled to room temperature by using refrigeration equipment, and then cut according to the specifications to obtain the bamboo expansion multi-layer board A, as shown in FIGS. 1-4;

[0037] The cooling of S4 can also be performed in a natural cooling manner, but compared with natural cooling, rapid cooling by using a refrigeration device, such as an air cooler, can make the flatness of the bamboo expanded multi-layer board better.

[0038] The bamboo expanded multi-layer board A includes six layers of bamboo sheet layers stacked together, each bamboo sheet layer is spliced by 20 bamboo sheets with a width of 50 mm, a length of 1 m and a thickness of 2 mm (only part is shown in the figure), the splicing direction is perpendicular to the fiber direction of the bamboo sheet, the fiber direction of the bamboo sheets in the same bamboo sheet layer is the same, and the fiber direction of the bamboo sheets in the adjacent two bamboo sheet layers is perpendicular to each other (i.e. the intersection angle is 90°), and the density difference between the bamboo sheets is 50 kg / m 3 The bamboo sheet layers are attached through the adhesive layer composed of glue, and the bamboo expanded multi-layer board is obtained after cutting.

[0039] In at least one embodiment, the preparation method of the bamboo expanded multi-layer board includes the following steps:

[0040] S1. First, the bamboo expanded board with a width of 50 mm and a length of 1 m is planed or rotary cut into bamboo sheets with a thickness of 2 mm;

[0041] S2. Control the moisture content of the bamboo sheet to be 15%, and then detect the density of the bamboo sheet; according to the density of the bamboo sheet, select the bamboo sheet with a density difference of 50 kg / m 3 , and splice in the direction perpendicular to the fiber direction; the fiber direction of the bamboo sheets in the same layer is the same (parallel to each other) during splicing, and six single-layer bamboo materials are obtained;

[0042] S3. After gluing on one side of the five single-layer bamboo materials, drying is performed, and then hot pressing is performed after stacking, and the hot pressing temperature is 120°C; the fiber direction of the bamboo sheets in the adjacent two layers is perpendicular to each other (i.e. 90°) during stacking;

[0043] S4. The multi-layer board after hot pressing is rapidly cooled to room temperature by using a refrigeration device, and then cut according to the specifications to obtain the bamboo expanded multi-layer board B.

[0044] In at least one embodiment, the preparation method of the bamboo expanded multi-layer board includes the following steps:

[0045] S1. First, the bamboo expanded board with a width of 50 mm and a length of 1 m is planed or rotary cut into bamboo sheets with a thickness of 2 mm;

[0046] S2. Control the moisture content of the bamboo sheet to be 15%, and then detect the density of the bamboo sheet; according to the density of the bamboo sheet, select the bamboo sheet with a density difference of 50 kg / m 3 , and splice in the direction perpendicular to the fiber direction; the fiber direction of the bamboo sheets in the same layer is the same (parallel to each other) during splicing, and six single-layer bamboo materials are obtained;

[0047] S3. Glue is applied to one side of the 4 single-layer bamboo materials, which are then dried and stacked before being hot-pressed at a temperature of 120°C; the bamboo fibers of adjacent layers are perpendicular to each other (i.e., at 90°) when stacked;

[0048] S4. The multi-layer board after hot-pressing is rapidly cooled to room temperature using refrigeration equipment, and then cut according to specifications to obtain the bamboo-unfolded multi-layer board C.

[0049] In at least one embodiment, a method for preparing a bamboo-unfolded multi-layer board includes the following steps:

[0050] S1. Bamboo-unfolded boards with a width of 50 mm and a length of 1 m are planed or rotary cut into bamboo strips with a thickness of 2 mm;

[0051] S2. The moisture content of the bamboo strips is controlled to be 15%, and the density of the bamboo strips is then detected; according to the density of the bamboo strips, bamboo strips with a density difference of 50 kg / m 3 are selected and spliced in a direction perpendicular to the fiber direction; the bamboo strips in the same layer have the same fiber direction (parallel to each other) when spliced, and 6 single-layer bamboo materials are obtained;

[0052] S3. Glue is applied to one side of the 3 single-layer bamboo materials, which are then dried and stacked before being hot-pressed at a temperature of 120°C; the bamboo fibers of adjacent layers are perpendicular to each other (i.e., at 90°) when stacked;

[0053] S4. The multi-layer board after hot-pressing is rapidly cooled to room temperature using refrigeration equipment, and then cut according to specifications to obtain the bamboo-unfolded multi-layer board D.

[0054] The density and MOR of the bamboo-unfolded multi-layer boards A, B, C, and D are detected, and compared with birch multi-layer boards of the same thickness. The results are shown in Table 1.

[0055] Table 1

[0056]

[0057] In at least one embodiment, a bamboo-unfolded multi-layer board includes 7 layers of bamboo strip layers stacked, each bamboo strip layer being spliced from 6 bamboo strips with a width of 200 mm, a length of 1.5 m, and a thickness of 1.5 mm, the splicing direction being perpendicular to the fiber direction of the bamboo strips, the fiber direction of the bamboo strips in the same bamboo strip layer being the same, the fiber direction of the bamboo strips of adjacent bamboo strip layers being perpendicular to each other, the density difference between the bamboo strips being 50-100 kg / m 3 , the bamboo strip layers being attached through an adhesive layer composed of glue, and the bamboo-unfolded multi-layer board being obtained after cutting.

[0058] In at least one embodiment, a method for preparing a bamboo-unfolded multi-layer board includes the following steps:

[0059] S1. First, a bamboo expansion board with a width of 200 mm and a length of 1.5 m is planed or rotary cut into bamboo pieces with a thickness of 1.5 mm;

[0060] S2. The moisture content of the bamboo pieces is controlled to be 15%, and then the density of the bamboo pieces is detected; according to the density of the bamboo pieces, bamboo pieces with a density difference of 50-100 kg / m 3 are selected and are spliced in a direction perpendicular to the fiber direction; the fiber directions of the bamboo pieces in the same layer are the same (parallel to each other) during splicing, and seven single-layer bamboo materials are obtained;

[0061] S3. After gluing on one side of the seven single-layer bamboo materials, drying is performed, and then stacking and hot pressing are performed, and the hot pressing temperature is 100°C; the bamboo fiber directions of the bamboo pieces in adjacent two layers are perpendicular to each other during stacking;

[0062] S4. The multi-layer board after hot pressing is naturally cooled to room temperature, and then cut according to the specifications, and a bamboo expansion multi-layer board is obtained.

[0063] In at least one embodiment, the bamboo expansion multi-layer board comprises five bamboo piece layers stacked, each bamboo piece layer is spliced by 40 bamboo pieces with a width of 100 mm, a length of 4 m, and a thickness of 4 mm, the splicing direction is perpendicular to the fiber direction of the bamboo pieces, the fiber directions of the bamboo pieces in the same bamboo piece layer are the same, the fiber directions of the bamboo pieces in adjacent two bamboo piece layers are perpendicular to each other, the density difference between the bamboo pieces is 150-200 kg / m 3 , the bamboo piece layers are attached through an adhesive layer, and the bamboo expansion multi-layer board is obtained after cutting.

[0064] In at least one embodiment, a method for preparing a bamboo expansion multi-layer board comprises the following steps:

[0065] S1. First, a bamboo expansion board with a width of 100 mm and a length of 4 m is planed or rotary cut into bamboo pieces with a thickness of 4 mm;

[0066] S2. The moisture content of the bamboo pieces is controlled to be 15%, and then the density of the bamboo pieces is detected; according to the density of the bamboo pieces, bamboo pieces with a density difference of 150-200 kg / m 3 are selected and are spliced in a direction perpendicular to the fiber direction; the fiber directions of the bamboo pieces in the same layer are the same (parallel to each other) during splicing, and five single-layer bamboo materials are obtained;

[0067] S3. After gluing on one side of the five single-layer bamboo materials, drying is performed, and then stacking and hot pressing are performed, and the hot pressing temperature is 180°C; the bamboo fiber directions of the bamboo pieces in adjacent two layers are perpendicular to each other during stacking;

[0068] S4. The multi-layer board after hot pressing is naturally cooled to room temperature, and then cut according to the specifications, and a bamboo expansion multi-layer board is obtained.

[0069] In at least one embodiment, the bamboo expanded multi-layer board comprises 9 layers of bamboo sheet layers arranged in a stack, each bamboo sheet layer is spliced by 30 bamboo sheets with a width of 70 mm, a length of 2.5 m and a thickness of 3 mm, the splicing direction is perpendicular to the fiber direction of the bamboo sheets, the fiber directions of the bamboo sheets in the same bamboo sheet layer are the same, the fiber directions of the bamboo sheets of adjacent two bamboo sheet layers are perpendicular to each other, the density difference between the bamboo sheets is 80 kg / m 3 , the bamboo sheet layers are attached through the adhesive layer composed of glue, and the bamboo expanded multi-layer board is obtained by cutting.

[0070] In at least one embodiment, the method for preparing the bamboo expanded multi-layer board comprises the following steps:

[0071] S1. First, the bamboo expanded board with a width of 70 mm and a length of 2.5 m is sliced or rotary cut into bamboo sheets with a thickness of 3 mm;

[0072] S2. Control the moisture content of the bamboo sheets to be 15%, and then detect the density of the bamboo sheets; according to the density of the bamboo sheets, select the bamboo sheets with a density difference of 80 kg / m 3 , and splice in a direction perpendicular to the fiber direction; the fiber directions of the bamboo sheets in the same layer are the same (parallel to each other) during splicing, and 9 single-layer bamboo materials are obtained;

[0073] S3. After gluing on one side of the 9 single-layer bamboo materials, drying is performed, and then hot pressing is performed after stacking, the temperature of hot pressing is 180℃; the fiber directions of the bamboo sheets of adjacent two layers are perpendicular to each other during stacking;

[0074] S4. The multi-layer board after hot pressing is naturally cooled to room temperature, and then cut according to the specifications to obtain the bamboo expanded multi-layer board.

[0075] In at least one embodiment, the bamboo expanded multi-layer board comprises 15 layers of bamboo sheet layers arranged in a stack, each bamboo sheet layer is spliced by 25 bamboo sheets with a width of 80 mm, a length of 2 m and a thickness of 0.5 mm, the splicing direction is perpendicular to the fiber direction of the bamboo sheets, the fiber directions of the bamboo sheets in the same bamboo sheet layer are the same, the fiber directions of the bamboo sheets of adjacent two bamboo sheet layers are perpendicular to each other, the density difference between the bamboo sheets is ≤110 kg / m 3 , the bamboo sheet layers are attached through the adhesive layer composed of glue, and the bamboo expanded multi-layer board is obtained by cutting.

[0076] In at least one embodiment, the method for preparing the bamboo expanded multi-layer board comprises the following steps:

[0077] S1. First, the bamboo expanded board with a width of 80 mm and a length of 2 m is sliced or rotary cut into bamboo sheets with a thickness of 0.5 mm;

[0078] S2. Control the moisture content of the bamboo sheets to be 15%, and then detect the density of the bamboo sheets; according to the density of the bamboo sheets, select the bamboo sheets with a density difference of 110 kg / m3 The bamboo pieces with a density difference of 50 kg / m

[0079] S3. After gluing on one side of the 15 single-layer bamboo materials, drying is performed, and then stacking is performed, and hot pressing is performed at a temperature of 70°C; during stacking, the bamboo fiber directions of the adjacent two layers of bamboo pieces are perpendicular to each other;

[0080] S4. After hot pressing, the multi-layer board is naturally cooled to room temperature, and then cutting is performed according to specifications, and a bamboo unfolding multi-layer board is obtained.

[0081] In at least one embodiment, a method for preparing a bamboo unfolding multi-layer board includes the following steps:

[0082] S1. First, a bamboo unfolding board with a width of 50 mm and a length of 1 m is planed or rotary cut into bamboo pieces with a thickness of 2 mm;

[0083] S2. The moisture content of the bamboo pieces is controlled to be 15%, and then the density of the bamboo pieces is detected; according to the density of the bamboo pieces, bamboo pieces with a density difference of 50 kg / m 3 are selected, and the bamboo pieces are spliced in a direction perpendicular to the fiber direction; during splicing, the fiber directions of the bamboo pieces in the same layer are the same (parallel to each other), and 6 single-layer bamboo materials are obtained;

[0084] S3. After gluing on one side of the 6 single-layer bamboo materials, stacking is performed, and pressing is performed at room temperature; during stacking, the bamboo fiber directions of the adjacent two layers of bamboo pieces are perpendicular to each other (i.e., 90°);

[0085] S4. After pressing at room temperature (i.e., cold pressing), cutting is performed according to specifications, and a bamboo unfolding multi-layer board is obtained.

[0086] In at least one embodiment, a method for preparing a bamboo unfolding multi-layer board includes the following steps:

[0087] S1. First, a bamboo unfolding board with a width of 50 mm and a length of 1 m is planed or rotary cut into bamboo pieces with a thickness of 2 mm;

[0088] S2. The moisture content of the bamboo pieces is controlled to be 15%, and then the density of the bamboo pieces is detected; according to the density of the bamboo pieces, bamboo pieces with a density difference of 50 kg / m 3 are selected, and the bamboo pieces are spliced in a direction perpendicular to the fiber direction; during splicing, the fiber directions of the bamboo pieces in the same layer are the same (parallel to each other), and 6 single-layer bamboo materials are obtained;

[0089] S3.6 single-layer bamboo materials are grouped into 3 groups, two by two. First, two single-layer bamboo materials in the same group are glued, dried and hot-pressed (hot-pressing temperature is 120℃) to realize bonding, and the bamboo fibers of the adjacent two layers of the two single-layer bamboo materials in the same group are in the same direction. Then, the three groups of bamboo materials are stacked in a direction perpendicular to the fiber direction, and are glued, dried and hot-pressed to realize bonding.

[0090] S4. After cold pressing at room temperature, the bamboo expanded multi-layer board is obtained by cutting according to the specifications.

[0091] Due to the density difference of the bamboo chips, the two-by-two fiber direction in the same group and the fiber direction offset between groups are used for stacking and bonding, which can use the bamboo yellow to bamboo yellow and the fiber direction stacking unit as the basic unit of the invisible deformation stress, and can ensure the flatness of the maximum width bamboo expanded multi-layer board after the product is made.

[0092] In at least one embodiment, the bamboo expanded multi-layer board comprises 7 layers of bamboo chip layers stacked, each bamboo chip layer is composed of 25 bamboo chips with a width of 60mm, a length of 1.5m and a thickness of 1.8mm, the direction of splicing is perpendicular to the fiber direction of the bamboo chips, the fiber direction of the bamboo chips in the same bamboo chip layer is the same, the fiber direction of the bamboo chips in the adjacent two bamboo chip layers is perpendicular to each other, and the density difference between the bamboo chips is 60~90kg / m 3 , the bamboo chip layers are bonded by the adhesive layer, and the bamboo expanded multi-layer board is obtained by cutting.

[0093] In at least one embodiment, the method for preparing the bamboo expanded multi-layer board comprises the following steps:

[0094] S1. First, the bamboo expanded board with a width of 90mm and a length of 3m is planed or rotary cut into bamboo chips with a thickness of 2.6mm;

[0095] S2. The moisture content of the bamboo chips is controlled to be 13.5%, and then the density of the bamboo chips is detected; according to the density of the bamboo chips, the bamboo chips with a density difference of 70~100 kg / m 3 are selected and spliced in a direction perpendicular to the fiber direction; the fiber direction of the bamboo chips in the same layer is the same (parallel to each other) during splicing, and 5 single-layer bamboo materials (i.e. 5 bamboo chip layers) are obtained;

[0096] S3. After gluing on one side of the 5 single-layer bamboo materials, drying, and then stacking and hot-pressing, the hot-pressing temperature is 110℃; the fiber direction of the adjacent two layers of the bamboo chips is perpendicular to each other (i.e. 90°);

[0097] S4. The multi-layer board after hot-pressing is rapidly cooled to room temperature by refrigeration equipment, and then cut according to the specifications to obtain the bamboo expanded multi-layer board.

[0098] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent transformation or direct or indirect application in the related technical field based on the content of the present application specification and drawings is also included in the patent protection scope of the present application.

Claims

1. Bamboo expanded multi-layered board, characterized by, The bamboo sheet layer comprises at least two bamboo sheets which are spliced with each other, the bamboo fiber directions of the bamboo sheets of two adjacent bamboo sheet layers intersect, and the density difference between the bamboo sheets in the same layer is ≤200 kg / m 3 .

2. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The density difference between the bamboo pieces in different layers is ≤ 200 kg / m 3 .

3. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The thickness of the bamboo piece is 0.5-4mm.

4. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The width of the bamboo piece is ≥50mm.

5. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The bamboo fiber direction of the bamboo pieces in the same layer is parallel to each other.

6. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The bamboo fiber direction of the bamboo pieces in adjacent two layers is perpendicular to each other.

7. The bamboo-unfolded multi-layered panel according to claim 1, wherein, The number of the bamboo piece layers is odd.

8. A method for manufacturing the bamboo expanded multi-layered panel according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: First, a bamboo unfolding plate is made into a bamboo piece; Then, the bamboo piece layers obtained after splicing the bamboo pieces are laminated.

9. The method of claim 8, wherein the bamboo unwinding multilayer sheet is prepared by the steps of: The method further comprises the steps of gluing and drying between the splicing and the laminating.

10. The method of claim 8, wherein the bamboo unwinding multilayer sheet is prepared by the steps of: The temperature of the laminating is 70-180℃. ​

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