An electric heating bamboo-wood composite particle board, an electric heating floor based thereon and a preparation method thereof

Abstract

This invention discloses an electrically heated bamboo-wood composite particleboard, an electrically heated floor based thereon, and a method for preparing the same. The electrically heated bamboo-wood composite particleboard of this invention is a multi-layered bamboo-wood structure particleboard with electrothermal function, and the board has a centrally symmetrical structure. The electrically heated bamboo-wood composite particleboard includes an upper surface layer, an upper reinforcing layer, an electrothermal layer, a lower reinforcing layer, and a lower surface layer. The upper and lower surface layers are composed of wood shavings, the upper and lower reinforcing layers are composed of large, thin wood shavings, and the electrothermal layer is composed of modified bamboo shavings. These modified bamboo shavings are obtained by impregnating bamboo shavings in sodium hydroxide, modifying them, and then carbonizing them. The electrically heated bamboo-wood composite particleboard prepared by this invention has enhanced bonding strength, good insulation performance, and high safety; it has the same dimensions as conventional flooring, making it easy to lay; and multiple points of electricity ensure uniform heating of the board.

Description

Technical Field

[0001] The invention relates to the technical field of artificial boards, and in particular to an electric heating bamboo-wood composite particle board, an electric heating floor based thereon and a preparation method thereof. Background Art

[0002] Electric floor heating has the advantages of being green and environmentally friendly, high energy utilization, small footprint, and uniform heat radiation. It has gradually become one of the development trends in the heating field. With the increasing demand for quality of life, electric floor heating substrates with low prices, superior performance, and safe use are gradually needed by the people. At present, the common electric heating artificial boards on the market mostly use two fiberboards as the base material, with carbon fiber paper or electric heating paper pressed twice in the middle, and there are also electric heating wires installed on the back of the base plate.

[0003] Most of the existing electric heating floors use electric heating paper sandwiched between two layers of substrates. It takes at least four hot pressings including the stickers on the upper and lower surfaces. The process is complicated, energy-intensive and will cause the mechanical properties of the board to deteriorate. Fiberboard is too dense as a floor substrate, which has high transportation costs and relatively weak moisture resistance. Summary of the invention

[0004] In view of the problems that the existing electric heating floors have complex structures and often require secondary pressing, and the original substrates are mainly fiberboards, which have too high density, high transportation costs and poor waterproofness, the present invention provides an electric heating bamboo-wood composite particleboard, an electric heating floor based on the same and a preparation method thereof.

[0005] The present invention provides an electric heating bamboo-wood composite particleboard, which is a multi-layer bamboo-wood structure particleboard with an electric heating function, and the board is a central symmetrical structure; the electric heating bamboo-wood composite particleboard comprises an upper surface layer, an upper reinforcement layer, an electric heating layer, a lower reinforcement layer and a lower surface layer, and the mass ratio of the components of each layer is 1-2:3-5:2-4:3-5:1-2 in sequence;

[0006] The raw material components of the upper and lower surface layers are the same wood shavings, the shavings are 10mm to 20mm in length, 3mm to 5mm in width, and 0.3mm to 0.7mm in thickness; the upper and lower surface layers are formed by non-directional paving of the wood shavings after gluing;

[0007] The upper and lower reinforcing layers are composed of the same large thin wood shavings, the length of the wood shavings is 30mm-50mm, the width is 10mm-20mm, and the thickness is 0.3mm-0.7mm; the upper and lower reinforcing layers are both formed by non-directional paving of the large thin wood shavings after gluing;

[0008] The electric heating layer component is modified bamboo shavings, the shavings are 80mm to 100mm in length, 30mm to 50mm in width, 0.1mm to 0.5mm in thickness, and the shavings are in the shape of rectangular flakes;

[0009] The preparation method of the modified bamboo shavings used in the electric heating layer is as follows:

[0010] (1) soaking the bamboo shavings in 0.01-0.04 mol / L sodium hydroxide for 30-45 min, then washing and drying;

[0011] (2) dipping the dried bamboo shavings in the mixed modified liquid under negative pressure for 30 min to 40 min, and then drying at 120° C. for 120 min to 180 min;

[0012] (3) placing the bamboo shavings modified in step (2) in a tubular furnace for carbonization under nitrogen protection, first preheating at 100° C.-120° C. for 30 min, then heating to 1100° C.-1300° C. at a rate of 20-25° C. / min, carbonizing for 60 min-80 min, and taking out after cooling to obtain the modified bamboo shavings;

[0013] The mixed modified liquid is formed by mixing nickel sulfate, ferrous sulfate, copper sulfate and deionized water. The mass of the mixed modified liquid is 7-9 times the mass of the bamboo shavings immersed in step (2). The mass fractions of each component in the mixed modified liquid are as follows:

[0014]

[0015] The electric heating layer of the present invention is composed of a three-layer structure, and the mass ratio of the three-layer structure is 1:3 to 6:1. The adjacent layers are arranged vertically according to the fiber direction, and the shavings in the same layer are arranged in the same direction according to the fiber direction. The fiber direction of the shavings deviates from the horizontal and vertical vertical lines by less than 10°. The shavings in the middle layer are overlapped at one-half to one-third of the adjacent shavings in the same layer, and the shavings in the upper and lower layers are overlapped at one-third to one-fifth of the adjacent shavings in the same layer.

[0016] The design density of the electric heating bamboo-wood composite particleboard of the present invention is 750-800kg / m 3 , thickness is 20mm-25mm.

[0017] The moisture content of each layer of the electric heating bamboo-wood composite particle board is not higher than 15%.

[0018] The wood shavings used in the upper and lower surface layers of the present invention are prepared by peeling, slicing, screening and drying common wood materials used for artificial boards such as poplar, pine and eucalyptus.

[0019] The bamboo shavings used in the preparation of the modified bamboo shavings in the electric heating layer component of the present invention are obtained by slicing moso bamboo, and the moso bamboos are all the parts of the middle section of the bamboo without nodes.

[0020] The adhesive used in the upper and lower surface layers of the present invention is PMDI adhesive, and the amount of adhesive applied to the upper and lower surface layers is 4-5% of the absolute dry mass of the wood chips of the layer.

[0021] The adhesive used in the upper and lower reinforcing layers of the present invention is a mixture of PMDI and epoxy acrylate resin. The amount of PMDI adhesive applied in the upper and lower reinforcing layers is 5.5-6.5% of the absolute dry mass of the wood chips, and the amount of epoxy acrylate resin applied is 1%-2% of the absolute dry mass of the wood chips.

[0022] The adhesive used in the electric heating layer of the present invention is a mixture of modified hydroxyl acrylic resin and PMDI, the amount of PMDI adhesive applied is 0.5%-1.5% of the absolute dry mass of the wood chips of the layer, and the amount of modified hydroxyl acrylic resin applied is 6%-8% of the absolute dry mass of the wood chips of the layer;

[0023] The modified hydroxy acrylic resin is prepared by uniformly blending a hydroxy acrylic resin emulsion, graphite powder and a silane coupling agent, and the mass fractions of each component are as follows:

[0024] 6-8 parts of hydroxy acrylic resin emulsion,

[0025] 2-3 parts of graphite powder,

[0026] Silane coupling agent 0.5-0.7 parts.

[0027] The silane coupling agent is selected from any one or more of vinyl triperoxide tert-butylsilane, methacryloxysilane and butadienyl triethoxysilane.

[0028] The present invention also provides a method for preparing the above-mentioned electric heating bamboo-wood composite particleboard, comprising: laying and gluing the components of each layer of the above-mentioned electric heating bamboo-wood composite particleboard, and then hot pressing them using a hot press, the hot pressing temperature is 150°C, the unit pressure is 5MPa-6MPa, and the total hot pressing time is 800s-1000s, so as to obtain the electric heating bamboo-wood composite particleboard.

[0029] The present invention also provides an electric heating floor based on the electric heating bamboo-wood composite particleboard. The electric heating floor is manufactured by mechanical processing and circuit connection using the electric heating bamboo-wood composite particleboard or a veneer panel after veneer is used as a base material.

[0030] The specific preparation method of the electric heating floor based on the above-mentioned electric heating bamboo-wood composite particleboard is as follows:

[0031] (1) The base plate is processed into a rectangular strip of 165mm*1220mm, and the side of the base plate is subjected to conventional floor grooving treatment. Two rectangular grooves I with a size of 20mm*10mm*5mm are respectively opened at one quarter of the long side on the two short sides. The rectangular groove I is located in the center layer of the electric heating layer. Then, two rectangular grooves II with a size of 30mm*5mm*5mm are respectively opened at one sixth, one half, and five sixths of the two long sides. The two grooves are located in the upper and lower layers of the electric heating layer respectively;

[0032] (2) Holes are punched in each rectangular groove, with a hole size of 60 mm in depth and 6 mm in diameter, and cylindrical copper electrodes with a length of 65 mm and a diameter of 6 mm are driven into the holes. The long-side electrodes are first connected to the electrodes at the same position, and then connected to the circuit or connected to the long sides of the adjacent boards. The short-side electrodes are connected to the circuit or connected to the short sides of the adjacent boards. Finally, an electric heating floor based on an electric heating bamboo-wood composite particleboard is obtained.

[0033] The carbon atoms in bamboo fiber form a honeycomb crystal structure under high temperature and the catalytic action of nickel ions. Each carbon atom is connected to the other three carbon atoms through a σ bond, and each carbon atom contributes a free electron to form a π conjugated network system. The free electrons can move freely in the graphite-type carbon atom network. At the same time, since the cellulose in bamboo fiber is strictly arranged longitudinally, the graphite crystals formed by high-temperature carbonization are arranged longitudinally. Therefore, electrons can move freely in the electric heating layer of the strictly directional electric heating particleboard.

[0034] Due to the poor conductivity of adhesives, adding graphite and silane coupling agents to the adhesive of the electric heating layer can effectively improve the continuity of the current. When the electric heating layer is connected to the power supply through the electrodes at both ends, a conductive circuit is formed inside the plate. After power is applied, under the action of the electric field, the bamboo fiber graphite filaments in the conductive network and the carriers at their overlapping interfaces move violently, collide and rub against each other, and ultimately lose electrical energy in the form of heat release.

[0035] In the reinforcement layer, the addition of epoxy acrylic resin not only enhances the bonding strength but also greatly improves the insulation performance of the board, thereby improving the safety of the board.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The electric heating bamboo-wood composite particleboard prepared by the present invention has enhanced bonding strength, good insulation performance, and high safety;

[0038] (2) The board of the present invention has the same size as conventional floors, and is easy to lay; and multiple points of electricity are connected to ensure that the board is heated evenly;

[0039] (3) The floor prepared by using the electric heating bamboo-wood composite particleboard of the present invention has high strength and good performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The top view of the electric heating floor based on the electric heating bamboo-wood composite particleboard according to the present invention.

[0041] Figure 2 It is a side view of the long side of the electric heating floor based on the electric heating bamboo-wood composite particleboard according to the present invention.

[0042] Figure 3 It is a short side view of the electric heating floor based on the electric heating bamboo-wood composite particleboard according to the present invention.

[0043] Figure 4 This is a schematic diagram of the current after the electric heating floor circuit based on the electric heating bamboo-wood composite particleboard of the present invention is connected.

[0044] Figure 1-4 The markings are: 1-1 upper surface layer of composite particle board, 1-2 lower surface layer of composite particle board, 2-1 upper reinforcement layer of composite particle board, 2-2 lower reinforcement layer of composite particle board, 3-1 upper electric heating layer of composite particle board, 3-2 middle electric heating layer of composite particle board, 3-3 lower electric heating layer of composite particle board, 4 rectangular groove I, 5 rectangular groove II. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention may be implemented in many different forms, and the present invention should not be construed as being limited to the specific embodiments set forth herein. On the contrary, these embodiments are provided to explain the principles of the present invention and their practical applications, so that other persons skilled in the art can understand the various embodiments of the present invention and the various modifications suitable for specific intended applications.

[0046] Embodiment 1:

[0047] An electric heating bamboo-wood composite particleboard with a design density of 750kg / m 3 The plate has a central symmetrical structure; it includes an upper surface layer, an upper reinforcement layer, an electric heating layer, a lower reinforcement layer and a lower surface layer, and the mass ratio of the components of each layer is 1:5:3:5:1;

[0048] The pine wood is peeled, sliced, screened and dried to prepare flaky shavings with a length of 10mm-20mm, a width of 3mm-5mm and a thickness of 0.3mm-0.7mm as the raw materials for the upper and lower surface layers, and large thin shavings with a length of 30mm-50mm, a width of 10mm-20mm and a thickness of 0.3mm-0.7mm are used as the raw materials for the upper and lower reinforcing layers; the middle section of the bamboo without nodes is sliced, screened and dried to prepare rectangular shavings with a length of 80mm-100mm, a width of 30mm-50mm and a thickness of 0.1mm-0.5mm as the raw materials for the modified bamboo shavings of the electric heating layer component.

[0049] The preparation method of the modified bamboo shavings comprises the following steps: immersing the bamboo shavings in 0.03 mol / L sodium hydroxide for 40 minutes, then washing and drying; immersing the dried bamboo shavings in a mixed modification liquid which is 8 times the mass of the shavings and is prepared by mixing 2 parts by mass of nickel sulfate, 25 parts by mass of ferrous sulfate, 15 parts by mass of copper sulfate and 80 parts by mass of deionized water for 30 minutes under negative pressure, and then drying the mixed liquid at 120°C for 150 minutes; and then placing the dried bamboo shavings in a tubular furnace for carbonization under nitrogen protection, first preheating at 120°C for 30 minutes, then heating to 1200°C at a speed of 25°C / min, carbonizing for 70 minutes, cooling and taking out to obtain the modified bamboo shavings.

[0050] The upper and lower surface layers use PMDI as adhesive, and the applied amount is 4% of the mass of the wood chips.

[0051] The upper and lower reinforcing layers use PMDI in an amount of 5.5% of the mass of the wood chips and epoxy acrylate resin in an amount of 2% of the mass of the wood chips as adhesives.

[0052] The electric heating layer uses 8% of the mass of the wood chips, which is a modified hydroxy acrylic resin uniformly mixed with 76% of the mass of hydroxy acrylic resin emulsion, 19% of graphite powder and 4.7% of butadiene triethoxysilane, and 1.0% of the mass of the wood chips as PMDI as an adhesive.

[0053] The upper and lower surface layers are both formed by non-directional paving of the wood shavings after gluing.

[0054] The upper and lower reinforcing layers are both formed by non-directional paving of the large thin wood chips after gluing.

[0055] The electric heating layer is composed of a three-layer structure, and the mass ratio of the three-layer structure is 1:4:1. Adjacent layers are arranged vertically according to the fiber direction, and the shavings in the same layer are arranged in the same direction according to the fiber direction. The fiber direction of the shavings deviates from the horizontal and vertical vertical lines by less than 10°. The shavings in the middle layer are overlapped at one-half to one-third of the adjacent shavings in the same layer, and the shavings in the two side layers are overlapped at one-third to one-fifth of the adjacent shavings in the same layer.

[0056] After the particleboard is laid, it is hot pressed with a hot press, the hot pressing temperature is 150°C, the unit pressure is 6MPa, and the total hot pressing time is 800s, that is, the density of the obtained particleboard is 750kg / m 3 , electric heating bamboo-wood composite particleboard with a thickness of 20mm.

[0057] Embodiment 2:

[0058] In the description of Example 2, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Example 2 and Example 1 is that the thickness of the prepared electric heating bamboo-wood composite particleboard is 25 mm, the total hot pressing time is 1000 s, the amount of other materials is increased in proportion, and the rest is referred to as described in Example 1, that is, the density of the prepared board is 750 kg / m 3 , electric heating bamboo-wood composite particleboard with a thickness of 25mm.

[0059] Embodiment 3:

[0060] In the description of Example 3, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Example 3 and Example 1 is that the wood used for the upper and lower surface layers and the upper and lower reinforcing layers of the particle board is a mixed wood of poplar and eucalyptus, the ratio of the upper surface layer, the upper reinforcing layer, the electric heating layer, the lower reinforcing layer and the lower surface layer is 1.5:3:3:3:1.5, the PMDI glue amount of the reinforcing layer is PMDI 6.5%, the epoxy hydroxy acrylic resin amount is 1.5%, the surface layer adhesive amount is 5%, and the rest is referred to as described in Example 1, that is, the obtained density is 750kg / m 3 , electric heating bamboo-wood composite particleboard with a thickness of 20mm.

[0061] Embodiment 4:

[0062] In the description of Example 4, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Example 4 and Example 1 is that the mass ratio of the three-layer structure of the electric heating layer is 1:6:1, the modified hydroxy acrylic resin adhesive is composed of 72% hydroxy acrylic resin, 20.6% graphite, and 7.4% vinyl triperoxide tert-butyl silane, and the rest is as described in Example 1, that is, the obtained density is 750kg / m 3 , electric heating bamboo-wood composite particleboard with a thickness of 20mm.

[0063] Embodiment 5:

[0064] In the description of Example 5, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Example 5 and Example 1 is that the mixed impregnation liquid is mixed with 3 parts by mass of nickel sulfate, 20 parts by mass of ferrous sulfate, 12.5 parts by mass of copper sulfate and 70 parts by mass of deionized water, the mass of the mixed impregnation liquid is 7 times that of the bamboo shavings impregnated, the electric heating process of the bamboo shavings is to preheat at 100°C for 30 minutes, then heat to 1100°C at a rate of 20°C / min, carbonize for 80 minutes, and take out after cooling, and the rest is referred to as described in Example 1, that is, the obtained density is 750kg / m3 , electric heating bamboo-wood composite particleboard with a thickness of 20mm.

[0065] Embodiment 6:

[0066] In the description of Example 6, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Example 6 and Example 1 is that the density of the prepared particle board is 800 kg / m 3 The materials are increased in proportion, and the rest are referred to in Example 1, that is, the density is 800kg / m 3 , electric heating bamboo-wood composite particleboard with a thickness of 20mm.

[0067] Comparative Example 1:

[0068] In the description of comparative example 1, the same points as those of example 1 are not described here, and only the differences from example 1 are described. The difference between comparative example 1 and example 1 is that the bamboo shavings are not subjected to carbonization treatment, and the rest is as described in example 1, that is, the obtained density is 750 kg / m 3 , composite particle board with a thickness of 20mm.

[0069] Comparative Example 2:

[0070] In the description of Comparative Example 2, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Comparative Example 2 and Example 1 is that the bamboo shavings are not treated with sodium hydroxide, and the rest is referred to as described in Example 1, that is, the obtained density is 750kg / m 3 , composite particle board with a thickness of 20mm.

[0071] Comparative Example 3:

[0072] In the description of Comparative Example 3, the same points as those in Example 1 are not described here, and only the differences from Example 1 are described. The difference between Comparative Example 3 and Example 1 is that the bamboo shavings are not modified and impregnated before carbonization, and the rest is referred to as described in Example 1, that is, the obtained density is 750kg / m 3 , composite particle board with a thickness of 20mm.

[0073] Comparative Example 4:

[0074] In the description of comparative example 4, the same points as those in Example 1 are not described here, and only the differences from Example 1 are described. The difference between comparative example 4 and Example 1 is that the electric heating layer does not use bamboo shavings, but uses pine shavings of the same specifications for the same treatment, and the rest is referred to in Example 1, that is, the density of the obtained shavings is 750kg / m 3 , composite particle board with a thickness of 20mm.

[0075] Comparative Example 5:

[0076] In the description of comparative example 5, the same points as those of example 1 are not described here, and only the differences from example 1 are described. The difference between comparative example 5 and example 1 is that the reinforcing layer does not add epoxy hydroxy acrylic resin, but is replaced by PMDI of the same mass, that is, the obtained density is 750 kg / m 3 , composite particle board with a thickness of 20mm.

[0077] Comparative Example 6:

[0078] In the description of comparative example 6, the same points as those of example 1 are not described here, and only the differences from example 1 are described. The difference between comparative example 6 and example 1 is that the ratio of the upper surface layer, the upper reinforcement layer, the electric heating layer, the lower reinforcement layer and the lower surface layer is 3:2:6:2:3, and the rest is as described in example 1, that is, the density of the obtained 3 , composite particle board with a thickness of 20mm.

[0079] Comparative Example 7:

[0080] In the description of Comparative Example 7, the same points as those in Example 1 are not described here, and only the differences from Example 1 are described. The difference between Comparative Example 7 and Example 1 is that nickel sulfate is not added to the impregnation solution, but copper sulfate of the same mass is added instead, and the rest is referred to as in Example 1, that is, the density of the obtained product is 750 kg / m 3 , composite particle board with a thickness of 20mm.

[0081] Comparative Example 8:

[0082] In the description of Comparative Example 8, the same points as Example 1 are not repeated here, and only the differences from Example 1 are described. The difference between Comparative Example 8 and Example 1 is that no graphite is added to the adhesive used in the electric heating layer, and the rest is referred to as described in Example 1, that is, the density of the obtained 3 , composite particle board with a thickness of 20mm.

[0083] Comparative Example 9

[0084] The density of the particleboard purchased on the market that meets the P3 type requirements in GB / T 4897-2015 "Particleboard" is 750kg / m 3 , particle board for floor substrate with a thickness of 20mm.

[0085] Comparative Example 10

[0086] The 20mm floor heating floor purchased on the market meets the requirements of LY / T 3192-2020 "Electric Heating Wood Floor with Built-in Electric Heating Layer".

[0087] The above embodiments and comparative examples 1-10 were processed into floors according to the instructions and relevant tests were performed, as shown in Table 1 and Table 2. The experimental data are as follows, where standard value 1 is LY / T 3192-2020 "Electrically heated wooden floor with built-in electric heating layer", and standard value 2 is the requirement for 20mm-25mm thick, P4 type particle board in GB / T 4897-2015 "Particle board", for reference only, the test environment temperature is 5°C, and the voltage is 220V household voltage transformed to 36V and then connected:

[0088] Table 1 Test of electrical heating performance of plates in various embodiments and comparative examples

[0089]

[0090] Table 2 Mechanical properties test of plates in various embodiments and comparative examples

[0091]

[0092]

[0093] From the data in Table 1 and Table 2, we can find that:

[0094] Comparative Example 1 has not been carbonized and has no graphitized bamboo fiber inside. Since wood itself is an insulator, it hardly heats up.

[0095] Comparative Example 2 was not treated with sodium hydroxide, and the wax on the surface of the bamboo shavings cells caused insufficient interface bonding between the wood and the adhesive, affecting the internal bonding strength, resulting in a decrease in the internal bonding strength of the board.

[0096] In Comparative Example 3, no modified impregnation was performed before carbonization, and the graphitization ratio of the bamboo shavings in the electric heating layer was relatively low, and it was difficult for electrons to flow freely and smoothly inside the board. Therefore, the power density, heating efficiency and surface temperature were all lower than those in the embodiments.

[0097] Comparative Example 4 Since the pine wood shavings fibers are not strictly oriented like the bamboo wood shavings fibers, the current flow is not as smooth as when using pure bamboo shavings, so the power density, heating efficiency and surface temperature are all lower than those of the embodiments.

[0098] In comparative example 5, no epoxy acrylic resin is added, and the insulation of the board is reduced, resulting in an increase in leakage current under working conditions and a decrease in insulation resistance.

[0099] In comparative example 6, the proportion of electric heating layer is higher. Since the lignin and hemicellulose in the cell wall of wood are greatly reduced after carbonization compared with before conversation, the strength of bamboo wood cells is weakened. When the proportion of electric heating layer is higher, the internal bonding strength, static bending strength and elastic modulus of the board decrease accordingly.

[0100] In Comparative Example 7, nickel sulfate is not added to the impregnation solution, but an equal mass of copper sulfate is used instead. Since the bamboo fiber forms a honeycomb graphite crystal structure under the catalysis of nickel ions, while copper ions do not have this catalytic effect, the carbon formed is mostly amorphous carbon or transition carbon, which makes it difficult for electrons to flow smoothly inside the plate. Therefore, the power density, heating efficiency and surface temperature are all lower than those of the embodiments.

[0101] In Comparative Example 8, no graphite powder is added to the adhesive. Since the adhesive itself is insulating, electrons cannot freely jump between the wood chips, resulting in power density, heating efficiency and surface temperature being lower than those in the embodiments.

[0102] Comparative Example 9 is a conventional particle board for flooring without electric heating performance.

[0103] Comparative Example 10 is a floor heating floor purchased on the market. Its heating time is slower than that of the embodiments, and its insulation resistance is also lower than that of the embodiments. At the same time, due to the use of fiberboard as the base material, its water resistance is relatively poor.

Claims

1. An electric heating bamboo-wood composite particleboard, characterized in that: It is a multi-layer bamboo-wood structure particleboard with electric heating function, and the board is a central symmetrical structure; the electric heating bamboo-wood composite particleboard comprises an upper surface layer, an upper reinforcement layer, an electric heating layer, a lower reinforcement layer and a lower surface layer, and the mass ratio of the components of each layer is 1-2:3-5:2-4:3-5:1-2; The raw material components of the upper and lower surface layers are the same wood shavings, the shavings are 10mm to 20mm in length, 3mm to 5mm in width, and 0.3mm to 0.7mm in thickness; the upper and lower surface layers are formed by non-directional paving of the wood shavings after gluing; The upper and lower reinforcing layers are composed of the same large thin wood shavings, the length of the wood shavings is 30mm-50mm, the width is 10mm-20mm, and the thickness is 0.3mm-0.7mm; the upper and lower reinforcing layers are both formed by non-directional paving of the large thin wood shavings after gluing; The electric heating layer component is modified bamboo shavings, the shavings are 80mm to 100mm in length, 30mm to 50mm in width, 0.1mm to 0.5mm in thickness, and the shavings are in the shape of rectangular flakes; The preparation method of the modified bamboo shavings used in the electric heating layer is as follows: (1) soaking the bamboo shavings in 0.01-0.04 mol / L sodium hydroxide for 30-45 min, then washing and drying; (2) dipping the dried bamboo shavings in the mixed modified liquid under negative pressure for 30 min to 40 min, and then drying at 120° C. for 120 min to 180 min; (3) placing the bamboo shavings modified in step (2) in a tubular furnace for carbonization under nitrogen protection, first preheating at 100° C.-120° C. for 30 min, then heating to 1100° C.-1300° C. at a rate of 20-25° C. / min, carbonizing for 60 min-80 min, and taking out after cooling to obtain the modified bamboo shavings; The mixed modified liquid is formed by mixing nickel sulfate, ferrous sulfate, copper sulfate and deionized water, and the mass of the mixed modified liquid is 7-9 times the mass of the bamboo shavings immersed in step (2); The adhesive used in the electric heating layer is a mixture of modified hydroxyl acrylic resin and PMDI, the amount of PMDI adhesive applied is 0.5%-1.5% of the absolute dry mass of the wood chips in this layer, and the amount of modified hydroxyl acrylic resin applied is 6%-8% of the absolute dry mass of the wood chips in this layer; The modified hydroxy acrylic resin is prepared by uniformly blending a hydroxy acrylic resin emulsion, graphite powder and a silane coupling agent, and the mass fractions of each component are as follows: 6-8 parts of hydroxy acrylic resin emulsion, 2-3 parts of graphite powder, Silane coupling agent 0.5-0.7 parts; The silane coupling agent is selected from any one or more of vinyl triperoxide tert-butylsilane, methacryloxysilane and butadienyl triethoxysilane.

2. The electric heating bamboo-wood composite particleboard according to claim 1, characterized in that: In the preparation method of the modified bamboo shavings used in the electric heating layer, the mass fractions of the components in the mixed modified liquid are as follows: 1-3 parts of nickel sulfate, 15-25 parts of ferrous sulfate, 10-15 parts of copper sulfate, 70-90 parts of deionized water.

3. The electric heating bamboo-wood composite particleboard according to claim 1 or 2, characterized in that: The electric heating layer is composed of a three-layer structure, and the mass ratio of the three-layer structure is 1:3 to 6:

1. Adjacent layers are arranged vertically according to the fiber direction, and the shavings on the same layer are arranged in the same direction according to the fiber direction. The fiber direction of the shavings deviates from the horizontal and vertical vertical lines by less than 10°. The shavings on the middle layer are overlapped at one-half to one-third of the adjacent shavings on the same layer, and the shavings on the upper and lower layers are overlapped at one-third to one-fifth of the adjacent shavings on the same layer.

4. The electric heating bamboo-wood composite particleboard according to claim 3, characterized in that: The design density of the electric heating bamboo-wood composite particleboard is 750-800kg / m 3 , thickness is 20mm-25mm.

5. The electric heating bamboo-wood composite particleboard according to claim 4, characterized in that: The adhesive used in the upper and lower surface layers is PMDI adhesive, and the amount of adhesive applied to the upper and lower surface layers is 4-5% of the absolute dry weight of the wood chips in the layer respectively; The adhesive used in the upper and lower reinforcing layers is a mixture of PMDI and epoxy acrylate resin. The amount of PMDI adhesive applied in the upper and lower reinforcing layers is 5.5-6.5% of the absolute dry weight of the wood chips, and the amount of epoxy acrylate resin applied is 1%-2% of the absolute dry weight of the wood chips.

6. The electric heating bamboo-wood composite particleboard according to claim 5, characterized in that: The wood shavings used in the upper and lower surface layers are made of common wood materials such as poplar, pine and eucalyptus used for artificial boards, which are prepared by peeling, slicing, screening and drying; The bamboo shavings used in the preparation of the modified bamboo shavings in the electric heating layer component are obtained by slicing moso bamboo, and the moso bamboos are all the parts of the middle section of the bamboo without nodes.

7. The electric heating bamboo-wood composite particleboard according to claim 6, characterized in that: The moisture content of each layer of the electric heating bamboo-wood composite particle board is not higher than 15%.

8. The method for preparing an electric heating bamboo-wood composite particleboard according to any one of claims 1 to 7, characterized in that: include: The components of each layer of the electric heating bamboo-wood composite particleboard are laid and glued, and then hot-pressed using a hot press. The hot-pressing temperature is 150° C., the unit pressure is 5MPa-6MPa, and the total hot-pressing time is 800s-1000s to obtain the electric heating bamboo-wood composite particleboard.

9. An electric heating floor based on the electric heating bamboo-wood composite particleboard according to any one of claims 1 to 7, characterized in that: The electric heating floor is manufactured by mechanical processing and circuit connection using the electric heating bamboo-wood composite particle board or a veneer panel after veneer is performed on the electric heating bamboo-wood composite particle board as a base material as a base material.

10. The method for preparing an electric heating floor based on an electric heating bamboo-wood composite particleboard according to claim 9, characterized in that: The steps include: (1) The base plate is processed into a rectangular strip of 165mm*1220mm, and the side of the base plate is subjected to conventional floor grooving treatment. Two rectangular grooves I with a size of 20mm*10mm*5mm are respectively opened at one quarter of the long side on the two short sides. The rectangular groove I is located in the center layer of the electric heating layer. Then, two rectangular grooves II with a size of 30mm*5mm*5mm are respectively opened at one sixth, one half, and five sixths of the two long sides. The two grooves are located in the upper and lower layers of the electric heating layer respectively; (2) Holes are punched in each rectangular groove, with a hole size of 60 mm in depth and 6 mm in diameter, and cylindrical copper electrodes with a length of 65 mm and a diameter of 6 mm are driven into the holes. The long-side electrodes are first connected to the electrodes at the same position, and then connected to the circuit or connected to the long sides of the adjacent boards. The short-side electrodes are connected to the circuit or connected to the short sides of the adjacent boards. Finally, an electric heating floor based on an electric heating bamboo-wood composite particleboard is obtained.

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