Processing method of bamboo composite board

Abstract

The invention discloses a processing method of a bamboo composite board, which comprises the following steps: making raw bamboo into bamboo strips, arranging the bamboo strips along the length direction of a mold cavity of a hot press, and laying a lower bamboo strip layer with tabasheer of the bamboo strips facing upwards; paving a layer of thermosetting material on the lower bamboo strip layer to form a reinforcing layer; an upper-layer bamboo strip layer is laid on the reinforcing layer, bamboo strips of the upper-layer bamboo strip layer are also arranged in the length direction of the cavity of the hot press, and tabasheer of the bamboo strips is laid downwards; performing hot press molding, and fixing the upper bamboo strip layer and the thermosetting material lower bamboo strip layer together to form a blank plate; and board sawing is conducted according to the needed size, and the bamboo composite board is manufactured. The bamboo composite board has the advantages that the thermosetting material serves as the reinforcing layer, the bamboo strip layers are composited on the upper surface and the lower surface of the thermosetting material in a hot-pressing mode, the bamboo composite board is manufactured, the processing method is simple, the processing cost is low, and the manufactured bamboo composite board is good in strength and weather resistance.

Description

Technical Field

[0001] The invention relates to the technical field of composite boards, in particular to a processing method of a bamboo composite board. Background Art

[0002] Outdoor wood materials are an important part of my country's building decoration materials. Due to being exposed to the wild all year round and experiencing the test of harsh climates, we often find that the floor of the outdoor trail is cracked and warped when we go out to play, which not only affects the aesthetics, but also poses a safety hazard. Therefore, outdoor wood materials (especially outdoor floors) are required to have high strength, high weather resistance, and high wear resistance. This places high demands on the selection of outdoor wood. As wood resources become increasingly scarce, it is urgent to develop alternative materials. my country is rich in bamboo resources, and using bamboo materials to replace wood materials has become a trend.

[0003] Some existing outdoor floors are made of bamboo materials. They are made by stacking and gluing multiple layers of bamboo slices together. The directions of the bamboo slices on adjacent bamboo slice layers are staggered. For example, the first layer of bamboo slices is laid along the length direction of the outdoor floor, the second layer of bamboo slices is laid along the width direction of the outdoor floor, and the third layer of bamboo slices is laid along the length direction of the outdoor floor. In this way, a staggered structure is formed to increase the strength of the outdoor floor. However, since the bamboo material itself has limited strength and poor rigidity in the length direction, it is easy to bend.

[0004] The patent application with the existing application number CN201710797529.4 and the name of "An outdoor floor with a surface layer of long-bundle bamboo fiber and a manufacturing method thereof" discloses an outdoor floor and a manufacturing method thereof. The structure of the outdoor floor with a surface layer of long-bundle bamboo fiber is that the upper and lower surfaces are each a layer of bamboo fiber curtain, and the inner surface is a rolled bamboo silk or a 2-10-layer bamboo curtain; there can also be a layer of transparent phenolic impregnated paper on the upper surface of the upper surface bamboo fiber curtain, and there can also be a layer of resin impregnated paper on the lower surface of the lower surface bamboo fiber curtain. Its manufacturing method includes the following process steps: 1) making long-bundle bamboo fiber curtain, processing rolled bamboo silk and bamboo curtain; 2) dipping and drying; 3) assembling and hot pressing. However, it needs to process the raw bamboo into bamboo silk or bamboo curtain, which is more troublesome to process, and the outdoor floor made has poor strength, so it needs further improvement. Summary of the invention

[0005] The purpose of the present invention is to make up for the above-mentioned deficiencies and disclose to the public a processing method of a bamboo composite board, which uses a thermosetting material as a reinforcement layer and hot-presses a composite bamboo strip layer on the upper and lower surfaces of the thermosetting material to form a bamboo composite board. The processing method is simple and the processing cost is low. The prepared bamboo composite board has good strength and good weather resistance.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A method for processing a bamboo composite board comprises the following steps:

[0008] Step 1: Make the raw bamboo into bamboo strips;

[0009] Step 2: Arrange the bamboo strips along the length direction of the hot press mold cavity, and lay the lower bamboo strip layer with the bamboo strips facing upwards;

[0010] Step 3: Lay a layer of thermosetting material on the lower bamboo strip layer to form a reinforcement layer;

[0011] Step 4: Lay an upper bamboo strip layer on the reinforcement layer. The bamboo strips of the upper bamboo strip layer are also arranged along the length direction of the hot press cavity, and the bamboo strips are laid with the bamboo strips facing downwards.

[0012] Step 5: hot pressing to fix the upper bamboo strip layer and the lower bamboo strip layer of thermosetting material together to form a blank board;

[0013] Step 6: saw the boards according to the required size to obtain the bamboo composite boards.

[0014] The measures to further optimize this technical solution are:

[0015] Preferably, in the step 1, the moisture content of the bamboo strips is controlled below 5%.

[0016] Preferably, the specific steps of making raw bamboo into bamboo strips are: cutting, rough planing and fine planing the raw bamboo to obtain bamboo strips of required size, and then putting the bamboo strips into a drying room for drying until the bamboo strips no longer lose weight.

[0017] Preferably, the length of the bamboo strip is 1000mm to 2100mm, and the width of the bamboo strip is 10mm.

[0018] ~30mm, and the thickness of the bamboo strips is 3mm~10mm.

[0019] Preferably, in the step 1, paint is applied on the surface of the bamboo strips.

[0020] Preferably, the paint is outdoor water-based fluorocarbon paint.

[0021] Preferably, the mold of the hot press is provided with an exhaust structure

[0022] Preferably, in step five, the hot pressing temperature is 130° C. to 170° C., the hot pressing pressure is 4 MPa to 15 MPa, and the holding time is 8 min to 20 min.

[0023] Preferably, the thickness of the reinforcement layer is 2 mm to 3 mm.

[0024] Preferably, the thermosetting material is SMC.

[0025] The advantages of the present invention compared with the prior art are:

[0026] The processing method of the bamboo composite board of the present invention uses thermosetting material as the middle reinforcement layer, and hot presses composite bamboo strip layers on the upper and lower surfaces of the thermosetting material, and the bamboo strips are laid with the bamboo strips facing the thermosetting material to avoid bending of the bamboo strips during the hot pressing process, thereby causing deformation of the composite board. The bamboo composite board uses thermosetting material and bamboo as raw materials, has low processing cost, and the obtained bamboo composite board has good strength and good weather resistance, and is suitable for use as outdoor flooring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a mold of a hot press machine of the present invention;

[0028] Figure 2 yes Figure 1 Enlarged view of part A in the middle.

[0029] Reference numerals: mold 1, exhaust structure 11. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0031] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be used for other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0032] Those skilled in the art should understand that, in the disclosure of the present invention, the directions or positions indicated by the terms "longitudinal", "lateral", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, which are only simplified descriptions for the convenience of describing the present invention, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the above terms should not be understood as limitations on the present invention.

[0033] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0034] A method for processing a bamboo composite board comprises the following steps:

[0035] Step 1, making bamboo strips from raw bamboo: cutting, rough planing and fine planing the raw bamboo to obtain bamboo strips of required size, and then putting the bamboo strips into a drying room for drying until the bamboo strips no longer lose weight (the difference in the weight of the bamboo strips after two dryings is less than 0.1% of the weight of the latter bamboo strips, which is considered to be constant weight), at which time, the moisture content of the bamboo strips is less than 5%. The length of the bamboo strips is 1000mm to 2100mm, the width of the bamboo strips is 10mm to 30mm, and the thickness of the bamboo strips is 3mm to 10mm.

[0036] Step 2: Arrange the bamboo strips along the length direction of the cavity of the hot press mold 1, and lay the lower bamboo strip layer with the yellow side of the bamboo strips facing upwards.

[0037] Step 3: Lay a layer of thermosetting material on the lower bamboo strip layer to form a reinforcement layer; the thickness of the reinforcement layer is 2mm to 3mm. The thermosetting material is SMC, which has the advantages of high strength, corrosion resistance, and impact resistance.

[0038] Step 4: Lay the upper bamboo strip layer on the reinforcement layer. The bamboo strips of the upper bamboo strip layer are also arranged along the length direction of the cavity of the hot press mold 1, and the bamboo strips are laid with the yellow part facing downward. Bamboo consists of green bamboo, bamboo flesh, and yellow bamboo from the outside to the inside. Since there is a difference in shrinkage between green bamboo and yellow bamboo, when the bamboo is heated, the yellow bamboo shrinks more and the green bamboo shrinks less, which will produce an inward pulling force, causing the bamboo to bend in the direction of the yellow bamboo. In the bamboo composite board of the present invention, when the bamboo strips are laid, the yellow bamboo on both sides are laid toward the thermosetting material. First, the thermosetting material can be used as a support, and second, the inward bending forces of the bamboo strips on both sides can offset each other, so that the obtained bamboo composite board remains flat.

[0039] Step 5: Hot pressing to fix the upper bamboo strip layer and the lower bamboo strip layer of thermosetting material together to form a blank; the hot pressing temperature is 130°C to 170°C, the hot pressing pressure is 4Mpa to 15Mpa, and the holding time is 8min to 20min.

[0040] Step 6: saw the boards according to the required size to obtain the bamboo composite boards.

[0041] The bamboo composite board of the present invention uses a thermosetting material as a middle reinforcement layer, and bamboo strips are laid along the length direction on the upper and lower surfaces of the thermosetting material to form a bamboo strip layer, and then the bamboo strip layer and the reinforcement layer are hot-pressed and fixed together by hot pressing. Bamboo and thermosetting material are used as raw materials, and hot pressing is performed by a hot press machine, so the processing method is simple and the processing cost is low.

[0042] In the step 1, the moisture content of the bamboo strips is controlled below 5% to avoid high pressure due to evaporation of water during subsequent hot pressing.

[0043] In the step 1, paint is applied on the surface of the bamboo strips. The paint is outdoor water-based fluorocarbon paint. Water-based fluorocarbon paint is a high-performance two-component paint, an environmentally friendly one-component fluorocarbon emulsion paint with excellent performance water-based fluorocarbon resin as the main component, with excellent physical and chemical properties, weather resistance, easy construction, cleaning and long-term excellent gloss and color retention. It is suitable for ultra-durable decorative protective coatings for various building exterior walls, roofs and various building materials, which can greatly extend the service life of buildings.

[0044] During the pretreatment of bamboo strips, outdoor water-based fluorocarbon paint is brushed on the surface of the bamboo strips. In the subsequent hot pressing process, the hot pressing temperature is used to dry and cure the outdoor water-based fluorocarbon paint, which can save the trouble of painting and drying the bamboo composite board after it is made, thereby improving processing efficiency and reducing processing costs.

[0045] like Figure 1 and Figure 2 As shown, the mold 1 of the hot press is provided with an exhaust structure 11. In this embodiment, a semicircular groove is used as the exhaust structure 11, and the semicircular groove is opened on the long side of the mold 1. A through hole can also be opened on the mold 1 to serve as the exhaust structure 11. During hot pressing, the moisture in the bamboo strips may evaporate into water vapor due to heat (although the moisture content of the bamboo strips has been controlled during the processing, water vapor may still be generated). If the amount of water vapor generated is large, it will form local high pressure and affect the forming of the bamboo composite board, and even cause deformation of the bamboo composite board. The exhaust structure 11 is used to discharge the water vapor generated during the hot pressing of the bamboo composite board in time to ensure the hot pressing and forming quality of the bamboo composite board.

[0046] The performance of the bamboo composite board produced by the processing method of the present invention is tested: the sizes of the materials used in the experiment are reduced.

[0047] (1) The influence of bamboo strip arrangement on the strength of bamboo composite board:

[0048] Items required for the test: several bamboo strips with dimensions of 500×30×10mm and 400×30×10mm, SMC sheets with dimensions of 500×400×3mm, and a 100T rubber vulcanizing molding machine.

[0049] Arrangement method 1: Arrange bamboo strips with a size of 500×30×10mm into a rectangle of 400×500mm on the bottom surface, lay the SMC sheet on the bamboo strips in the middle, and then lay the top surface according to the arrangement direction of the bamboo strips on the bottom surface. Finally, put the combined materials into a rubber vulcanization molding machine for hot pressing. The hot pressing temperature is 170℃, the pressure is 5MPa, and the holding time is 20min.

[0050] Arrangement method 2: The bottom surface is arranged into a rectangle of 400×500mm with bamboo strips of 500×30×10mm, the SMC sheet is laid flat on the bamboo in the middle, and then the top surface is laid in the bamboo arrangement direction perpendicular to the bottom surface. The size of the top bamboo strips is 400×30×10mm. Finally, the combined materials are placed in a rubber vulcanization molding machine for hot pressing. The hot pressing temperature is 170℃, the pressure is 5MPa, and the holding time is 20min.

[0051] The bamboo composite board prepared above was left to stand at room temperature and then tested for strength.

[0052]

[0053] From the above experimental results, it can be seen that the strength (bending strength, elastic modulus) of the bamboo strips arranged in the same direction on the bottom and top surfaces is much better than that of the bamboo strips arranged vertically on the bottom and top surfaces.

[0054] (2) Effect of hot pressing pressure on the strength of bamboo composite panels:

[0055] Items required for the test: several 500×30×10mm bamboo strips, several 400×500mm SMC sheets, and a 100T rubber vulcanizing molding machine.

[0056] On the bottom surface, bamboo strips are arranged into a rectangle with a size of 400×500mm, and the SMC sheet is laid flat on the bamboo strips in the middle. Then, the top surface is laid according to the arrangement direction of the bamboo strips on the bottom surface. Finally, the combined materials are placed in a rubber vulcanization molding machine for hot pressing. The hot pressing temperature is 170℃, and the pressures are set to 1MPa, 1.5MPa, 2MPa, 5MPa, and 10MPa respectively. The holding time is 20min, and a group of experiments are carried out at different pressures.

[0057] The bamboo composite panels formed by the above five groups of tests were tested for strength after being allowed to stand at room temperature.

[0058]

[0059]

[0060] From the above experimental results, it can be seen that the pressure applied during hot pressing has a direct impact on the strength of the bamboo composite board. When the applied pressure is between 1.5 and 2 MPa, the bending strength and elastic modulus of the bamboo composite board will increase the fastest. After the applied pressure reaches 5 MPa, the strength of the bamboo composite board will show a downward trend. Therefore, the pressure of hot pressing is preferably 5 MPa.

[0061] (3) Effect of moisture content of bamboo strips on the strength of bamboo composite panels:

[0062] Items required for the test: 500×30×10mm bamboo strips, 400×500mm SMC sheets, 100T rubber vulcanizing machine

[0063] The moisture content of the test cannot be precisely controlled, so the moisture content of the bamboo strips was controlled at about 15%, 10%, 8%, 5%, and 1% for the test. The bamboo strips were arranged into a rectangle with a size of 400×500mm on the bottom surface, and the SMC sheet was laid flat on the bamboo strips in the middle. Then, the top surface was laid according to the arrangement direction of the bamboo strips on the bottom surface. Finally, the combined materials were put into the rubber vulcanization molding machine for hot pressing. The hot pressing temperature was 170℃, the pressure was set to 5MPa, and the holding time was 20min. A group of tests were carried out for different moisture contents of bamboo strips.

[0064]

[0065] From the above experimental results, it can be seen that the moisture content of bamboo strips has a direct impact on the strength of bamboo composite boards. As the moisture content decreases, the strength of bamboo composite boards gradually increases. When the moisture content decreases from 8% to 5%, the bending strength of bamboo composite boards increases significantly, and the elastic modulus decreases slightly; when the moisture content decreases from 5% to 1%, the bending strength of bamboo composite boards increases, but the increase is not large. Therefore, in the case of taking into account the processing cost and strength, it is better to control the moisture content of bamboo strips below 5%.

[0066] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for processing a bamboo composite board, characterized in that: The following steps are involved: Step 1: Make the raw bamboo into bamboo strips; Step 2: Arrange the bamboo strips along the length direction of the cavity of the hot press mold (1), and lay the lower bamboo strip layer with the bamboo strips facing upwards; Step 3: Lay a layer of thermosetting material on the lower bamboo strip layer to form a reinforcement layer; Step 4: Lay an upper bamboo strip layer on the reinforcement layer, with the bamboo strips of the upper bamboo strip layer also arranged along the length direction of the cavity of the hot press mold (1), and laid with the bamboo strips facing downwards; Step 5: hot pressing to fix the upper bamboo strip layer and the lower bamboo strip layer of thermosetting material together to form a blank board; Step 6: saw the boards according to the required size to obtain the bamboo composite boards.

2. The method for processing a bamboo composite board according to claim 1, characterized in that: In the step 1, the moisture content of the bamboo strips is controlled below 5%.

3. The method for processing a bamboo composite board according to claim 2, characterized in that: The specific steps of making raw bamboo into bamboo strips are: cutting, rough planing and fine planing the raw bamboo to obtain bamboo strips of required size, and then putting the bamboo strips into a drying room for drying until the bamboo strips no longer lose weight.

4. The method for processing a bamboo composite board according to claim 3, characterized in that: The length of the bamboo strips is 1000 mm to 2100 mm, the width of the bamboo strips is 10 mm to 30 mm, and the thickness of the bamboo strips is 3 mm to 10 mm.

5. The method for processing a bamboo composite board according to claim 4, characterized in that: In the step 1, paint is applied on the surface of the bamboo strips.

6. The method for processing a bamboo composite board according to claim 5, characterized in that: The paint is outdoor water-based fluorocarbon paint.

7. The method for processing a bamboo composite board according to claim 1, characterized in that: The mold (1) of the hot press is provided with an exhaust structure (11).

8. The method for processing a bamboo composite board according to claim 1, characterized in that: In the step 5, the hot pressing temperature is 130° C. to 170° C., the hot pressing pressure is 4 MPa to 15 MPa, and the holding time is 8 min to 20 min.

9. The method for processing a bamboo composite board according to claim 1, characterized in that: The thickness of the reinforcement layer is 2mm~3mm.

10. The method for processing a bamboo composite board according to claim 1, characterized in that: The thermosetting material is SMC.

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