Compacted wood fiber board and its quantitative production method

Abstract

This invention provides a compacted wood fiber board and a method for its quantitative production. [Solution] A method for quantitatively producing crushed wood fiber compacted boards, comprising: uniformly mixing 55-80 parts by weight of crushed wood fiber powder and 40-60 parts by weight of lime milk to obtain a primary crushed wood fiber mixed material; uniformly mixing the primary crushed wood fiber mixed material with 8-12 parts by weight of resin particles to obtain a secondary crushed wood fiber mixed material; molding the secondary crushed wood fiber mixed material in a mold, and obtaining a crushed wood fiber prefabricated board after demolding; obtaining a semi-finished crushed wood fiber compacted board by high-frequency heating and pressurizing the crushed wood fiber prefabricated board; and cooling and curing the semi-finished crushed wood fiber compacted board to obtain a crushed wood fiber compacted board.

Description

Technical Field

[0001] The present invention belongs to the field of technology of crushed wood hot pressing plates, and specifically relates to crushed wood fiber compacted plates and their quantitative production methods.

Background Art

[0002] Hot-pressed crushed wood panels have the advantage of being able to utilize various types of crushed wood, being low-cost, and fully performing the function of wood, making them highly valued by log lumber production and processing manufacturers that generate large quantities of crushed wood. By using auxiliary agents, hot-pressed crushed wood panels can be given sound insulation, heat insulation, moisture resistance, decay and mold resistance, and fire resistance and flame retardancy by adjusting the auxiliary agents. Of these, hot-pressed crushed wood panels with fire resistance and flame retardancy have the widest range of applications. However, conventional technology makes it difficult to achieve both physical processing performance and flame retardancy, as well as to balance mass production and cost. In a series of Chinese patent technologies named "high-frequency compaction technology," Patent Document 1 discloses a method for manufacturing nut compaction panels based on high-frequency technology. These nut compaction panels have excellent processing performance and moisture resistance, and retain the unique aroma of nuts. The mixed material made from nut scraps and PVB resin particles, and the PVB interlayer, are manufactured by a pre-compression body manufacturing step, a heating and pressurizing treatment step, and cutting and polishing. When PVB resin fiber particles and PVB interlayers are mixed and used, they exhibit better water absorption and thickness expansion performance under appropriate high-frequency hot compression conditions. However, because PVB interlayers are used, paving time is generally long, and large-scale production requires high-performance equipment. Patent document 2 discloses a method for manufacturing a compacted wood fireproof board based on high-frequency technology, which involves compression bonding of pre-treated wood boards and first, second, and third flame-retardant films made with different flame retardants. However, this method uses wood boards as raw material, and the cost of the flame-retardant films is high, making it unsuitable for the production of hot-compressed crushed wood boards. Patent document 3 discloses a crushed wood compaction material and method based on high-frequency non-adhesive compaction technology, employing steps such as stirring dry resin particle material, resin film paving, and two hot compression compactions to produce laboratory-scale crushed wood multilayer boards. However, the crushed wood compaction material in this patent includes a wood board layer and a compacted crushed wood layer, and requires an artificial PVB interlayer in the lamination step, making automated production difficult. Therefore, there is a need for a compressed wood fiber board that can be mass-produced using conventional technology and has excellent physical properties and fire-resistant / flame-retardant properties. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] China patent CN111231046A [Patent Document 2] China patent CN111300558A [Patent Document 3] China patent CN109834776A [Patent Document 4] China patent CN109454721A [Patent Document 5] China patent CN211221135U [Patent Document 6] China patent CN111196407A [Patent Document 7] China patent CN210100243U [Patent Document 8] China patent CN109808013A [Patent Document 9] China patent CN209453742U [Patent Document 10] China patent CN115781855A [Overview of the project] [Problems that the invention aims to solve]

[0004] In response to the above technical problems, the present invention provides multiple types of wood fiber compacted boards and a quantitative production method for wood fiber compacted boards, and the main technical solutions are as follows. [Means for solving the problem]

[0005] In a first embodiment of the present invention, a quantitative production method for compressed wood fiber boards is provided. The process involves a material mixing step in which 55-80 parts by weight of crushed wood fiber powder and 40-60 parts by weight of lime milk are uniformly mixed to obtain a primary crushed wood fiber mixed material, and then 8-12 parts by weight of resin particles are uniformly mixed with the primary crushed wood fiber mixed material to obtain a secondary crushed wood fiber mixed material. The molding step involves placing the aforementioned secondary crushed wood fiber agitated mixture into a mold, molding it, and then demolding it to obtain a crushed wood fiber prefabricated board. The aforementioned prefabricated wood fiber board is subjected to high-frequency heating and pressurization to obtain a semi-finished product of a compressed wood fiber board, a compaction step in which the prefabricated wood fiber board is subjected to high-frequency heating and pressurization, The process includes a finishing step of lowering the temperature of the semi-finished product of the crushed wood fiber compacted board and curing it to obtain the crushed wood fiber compacted board.

[0006] A second aspect of the invention provides a quantitative production method for a flame-retardant compacted wood fiber board, which differs from the production method of the first aspect in the following respects: In the material stirring step, after obtaining the primary wood fiber stirring mixture, the primary wood fiber stirring mixture is uniformly stirred with 8-12 parts by weight of resin particles, 20-40 parts by weight of magnesium oxide, and 3-5 parts by weight of magnesium chloride to obtain a secondary wood fiber stirring mixture. [Effects of the Invention]

[0007] The beneficial effects of the present invention are as follows. First, in the material mixing step of the quantitative production method for crushed wood fiber compacted boards, the conventional dry material mixing is changed to first mixing a wet material with lime milk and crushed wood fiber powder, and then adding resin particles, omitting the resin film, and performing three heating and pressurizing treatments in the compaction step, limiting the moisture content and treatment time after each heating and pressurizing, and comparing them, the physical performance of mass-produced boards and laboratory boards is similar. Furthermore, it is possible to quantitatively produce crushed wood fiber compacted boards with balanced physical performance, and in particular, there is a significant improvement in the uniformity of the screw gripping force of the manufactured board material. Finally, by adding techniques such as magnesium oxide and magnesium chloride after the primary crushed wood fiber stirring and mixing material, a synergistic flame retardant effect of magnesium-based flame retardants and inorganic adhesives is achieved, significantly improving the flame retardant performance of the crushed wood fiber compacted boards. [Modes for carrying out the invention]

[0008] The following examples further illustrate the scope of the present invention, but should not be construed as limiting the invention. Any modification or substitution of the methods, steps, or conditions of the present invention, insofar as they do not depart from the spirit and substance of the invention, falls within the scope of the invention.

[0009] A method for producing a wood fiber compacted board provided in some embodiments of the present invention includes a step of mixing the materials, a step of molding, a step of compacting, and a step of finishing. In the step of mixing the ingredients The material stirring step of the present invention involves mixing and stirring the wood fiber powder and auxiliary materials to ultimately obtain a stirred wood fiber mixture.

[0010] The wood fiber powder of the present invention is produced by grinding and grinding wood such as low-quality wood and fruit tree buds into fine wood fiber powder with a mesh count of 180 mesh (particle size approximately 0.088 μm) to 300 mesh (particle size approximately 50 μm) using a wood fiber grinder. The types of wood fiber grinders include, but are not limited to, cutter type, drip type, ball mill, column mill, rod mill, tube mill, automatic mill, rotary die roller mill, vertical mill, multi-layer vertical mill, vertical roller mill, disc mill, DMC mill, etc. The low-quality wood includes fast-growing wood such as poplar, eucalyptus, cedar, and willow, and the cedar includes Japanese cedar, Japanese cedar, and Japanese cedar. The fruit tree buds include growing branches, fruiting branches, and fruiting mother branches of apple, pear, and peach. The equipment for processing wood chips includes, but is not limited to, wood chippers and wood shredders. The equipment for mixing and stirring wood fiber powder with auxiliary materials includes, but is not limited to, stirrers and material mixers. The material mixer has a power of 40-45KW and stirs at 25 revolutions per minute. The stirring time is not particularly limited and can be determined according to the actual mixing conditions of the materials.

[0011] The resin of the present invention comprises one or more ethylene-vinyl acetate copolymers (EVA) or polyolefin materials, wherein the polyolefin material is a mixture of one or at least two of polyethylene, polypropylene, modified polyethylene, modified polypropylene, or ethylene-based elastomers containing ethylene units. The modified polyethylene includes polyvinyl butyral resin (PVB), polyvinyl chloride resin (PVC), and polyvinyl formal (PVF), and the polyvinyl butyral resin (PVB) includes, but is not limited to, that manufactured by Shanghai Meibang Plastics Co., Ltd. The particle size of the resin particles of the present invention is 0.03-0.05 mm.

[0012] The flame retardant of the present invention comprises one or more of the following: phosphorus-based flame retardants, metal compound flame retardants, nitrogen-based flame retardants, boron-based flame retardants, nitrogen-phosphorus flame retardants, and magnesium-based flame retardants. The phosphorus-based flame retardant comprises an organophosphorus flame retardant and an inorganic phosphorus flame retardant, the organophosphorus flame retardant comprising pentaerythritol phosphate (PEPA), bis(2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methylene) phosphate melamine salt, bis(2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methylene)-pentabromobenzyl phosphate, and 2,4,6-tribromophenyl(2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methylene) phosphate, and the inorganic phosphorus flame retardant comprising one or more of ammonium dihydrogen phosphate, ammonium polyphosphate, guanidine nitrogen phosphorus phosphate, and diammonium hydrogen phosphate. The magnesium-based flame retardant comprises one or more of the following: magnesium hydroxide, light-calcined magnesium oxide (magnesium), magnesium chloride, and magnesium hexahydrate (halogen chips). The magnesium hydroxide includes nanoscale magnesium hydroxide fibers, nanoscale magnesium hydroxide sheets, and nanoscale magnesium hydroxide polyhedra. Of these, magnesium chloride and magnesium hexahydrate (halogen chips) are further used as curing agents.

[0013] The lime milk of the present invention is a suspension of 15-25% calcium hydroxide. The method for producing the lime milk of the present invention is a known technique. For example, water can be added to quicklime (calcium oxide) to produce a suspension of calcium hydroxide. The lime milk of the present invention serves as an inorganic adhesive and further undergoes a double replacement reaction with magnesium chloride to produce magnesium hydroxide as a flame retardant promoter. The reaction principle is Ca(OH)2 + MgCl2 → CaCl2 + Mg(OH)2.

[0014] Auxiliary materials such as the flame retardant, curing agent, lime milk (or quicklime) of the present invention need to be put in after passing through a 100-240 mesh sieve respectively to remove foreign matter with large particles.

[0015] The device used for stirring the materials in the material stirring step includes, but is not limited to, a stirrer or a material mixer.

[0016] In the forming step In the forming step of the present invention, a mold frame can be placed on the pressure plate of a hot press. The stirred and mixed material of secondary wood fibers is discharged into the mold frame, and mold clamping is performed. After its shape is stabilized, a pre-pressure bonding treatment is carried out using a hot press to obtain a wood fiber prefabricated board with a moisture content of 35%-40%. It is also possible to place a mold frame on the pressure plate of a hot press, discharge the stirred and mixed material of secondary wood fibers into the mold frame, perform a pre-pressure bonding treatment using a hot press, and then perform mold clamping after its shape is stabilized to obtain a wood fiber prefabricated board with a moisture content of 35%-40%.

[0017] The material conveying device includes, but is not limited to, a conveying belt or a conveying pipe connected to the discharge port position of a stirrer or a material mixer.

[0018] In a further embodiment of the molding step, the obtained wood fiber prefabricated board may be subjected to a step of cutting the edges or a step of polishing the edges, the cutting equipment including but not limited to a cutter, and the polishing equipment including but not limited to a polishing machine, to further tidy up the edges of the wood fiber prefabricated board obtained after cutting.

[0019] In the consolidation step The consolidation step of the present invention involves subjecting the above-mentioned prefabricated wood fiber board to heat and pressurize treatment to obtain a semi-finished product of consolidated wood fiber board. The consolidation method generally refers to the various hot bonding methods under high-frequency conditions described in Patent Documents 3, 2, and 1.

[0020] The equipment used in the consolidation process is a consolidation machine. The prefabricated wood fiber board may be heated and pressurized using the consolidation machine, and after heating and pressurizing once or multiple times under the same or different conditions, a semi-finished product of consolidated wood fiber board may be formed. Alternatively, after heating and pressurizing once or multiple times, the material may be further heated with high frequency and pressurized to form a semi-finished product of consolidated wood fiber board. For details on the consolidation equipment, please refer to Patent Documents 4, 5, 6, 7, 8, 9, and 10.

[0021] In the organization step The present invention involves performing a temperature-reducing curing treatment on a semi-finished product of crushed wood fiber compacted board to obtain a finished product of crushed wood fiber compacted board.

[0022] A curing area is set up for the finished crushed wood fiber compacted boards. This curing area is a space that provides ventilation, drying, maintains a normal temperature, and avoids external interference such as sunlight and rainwater. The curing space is a room of 10-20 square meters, and a certain amount of space is maintained between the surfaces of each crushed wood fiber compacted board within the curing area. The temperature in the curing area is controlled to 28-35°C and the humidity to 5%. The surface of the crushed wood fiber compacted boards is cooled to 50°C and then moved into the curing space for 7-15 days. A ventilation system is installed in the room to ventilate the curing space, and temperature and humidity monitoring equipment is installed in the room to monitor the temperature and humidity of the curing space.

[0023] The method for manufacturing wood fiber compacted boards provided in the embodiments of the present invention, using a "4:8 foot" wood fiber compacted board (width 4 feet (1220 mm), length 8 feet (2440 mm)) as an example, allows for a quantitative production efficiency of 30 cubic meters / hour or more of wood fiber compacted boards on a single production line. If the wood fiber compacted board is 12 mm thick, approximately 840 wood fiber compacted boards can be produced per hour.

[0024] The wood fiber compaction board of the present invention can be used as a substrate, and a decorative layer is attached to its surface.

[0025] The present invention will be further described below with reference to specific examples, where "parts" in the specific examples all refer to "parts by weight," which are converted after the material has been taken based on a weight unit such as kilograms (KG). Example 1

[0026] Regarding the preparation of materials, 55 parts poplar fiber powder, 40 parts lime milk, and 8 parts PVB particles were used, of which the lime milk was a 15% calcium hydroxide suspension. (1) In the step of mixing the ingredients For the primary wood fiber agitation mixture, 55 parts poplar fiber powder and 40 parts lime milk were uniformly mixed beforehand to form the primary wood fiber agitation mixture. Subsequently, the primary wood fiber agitation mixture and 8 parts PVB particles were uniformly mixed to obtain the secondary wood fiber agitation mixture. The materials were then transported to a compactor via material transport piping. The PVB used was in particulate form, with a particle size of 0.03 mm, and the poplar fiber powder had a mesh count of 180 mesh. (2) In the molding step A mixed material of secondary crushed wood fibers is placed in a mold, the mold is clamped, and after pre-pressing treatment, the mold is released to obtain a prefabricated board of crushed wood fibers with a moisture content of 35%. (3) In the consolidation step A prefabricated wood fiber board with a moisture content of 29% was obtained by the first heat-pressure treatment of the crushed wood fiber prefabricated board. The treatment temperature for the first heat-pressure treatment was 80°C, the treatment time was 2 min, and the compression ratio for the first treatment was 40%. The wood fiber prefabricated board subjected to the first heat-pressure treatment is subjected to a second heat-pressure treatment to obtain a wood fiber prefabricated board with a moisture content of 15%. The treatment temperature for the second heat-pressure treatment was 90°C, the treatment time was 2 min, and the compression ratio for the second treatment was 50%. The wood fiber prefabricated board subjected to the second heat-pressure treatment is subjected to a third heat-pressure treatment to obtain a wood fiber prefabricated board with a moisture content of 8%. This wood fiber prefabricated board subjected to the third heat-pressure treatment is a semi-finished product of compacted wood fiber board. The treatment temperature for the third heat-pressure treatment was 150°C, the treatment time was 2 min, and the compression ratio for the third treatment was 65%. (4) In the sorting step After the cooling treatment, the semi-finished product of the wood fiber compaction board was placed in a curing space for 15 days to obtain the wood fiber compaction board. Examples 2-4

[0027] Examples 2-4 provide a method for manufacturing compressed wood fiber boards, which includes all the steps of Example 1, with the differences being the parameters shown in Table 1. [Table 1] Examples 5-7

[0028] Examples 5-7 provide a method for manufacturing a wood fiber compaction board, which includes all the steps of Example 2, differing in that the compaction step has the parameters shown in Table 2. [Table 2] Comparative Example 1

[0029] In the material mixing step, 55 parts poplar fiber powder, 40 parts lime milk, and 8 parts PVB particles were simultaneously and uniformly mixed. The mixing time was the same as the sum of the two mixing times in Example 6. A mixed material of crushed wood fibers was obtained by mixing only once, and the quantitative production method for other crushed wood fiber compacted boards was the same as in Example 6. Comparative Example 2

[0030] Adopting the method of Example 12 in Chinese Patent CN109834776A, a layer of crushed wood and a PVB interlayer was laid between two adjacent wooden boards, with a mass ratio of 1:1 between the wooden boards and the crushed wood blocks, and the particle size of the crushed wood was 5 cm. A laminated wooden board was manufactured, and subsequently the laminated wooden board was subjected to high-frequency heating and pressurizing treatment to obtain an intermediate layer crushed wood compacted board (containing a wooden board layer, a crushed wood block layer, and a wooden board layer). Two wooden board layers of the intermediate layer crushed wood compacted board were then cut off to obtain a crushed wood compacted board. Comparative Example 3

[0031] The consolidation step process for Comparative Example 3 is shown in Table 3, and the quantitative production method for wood fiber consolidation boards, which is not shown, is the same as in Example 6. [Table 3]

[0032] (Test Example 1) Test for uniformity of surface density of board material The purpose of the test is to compare the uniformity of the surface density of the wood grain compacted boards produced by the test examples based on the methods of Examples 1-7 with the uniformity of the surface density of the comparative examples based on the manufacturing methods of Comparative Examples 1-3.

[0033] The test method involved using compressed wood (fiber) boards manufactured according to the manufacturing methods of Examples 1-7 and Comparative Examples 1-3, with each sample having the same length, width, and height (i.e., 1220mm*2440mm*12mm). The density was detected in different regions of the board surface (the surfaces in the length and width directions) of the same board material, specifically in the edge areas (5 test points on the short side and 10 test points on the long side, for a total of 30 edge test points) and the middle areas (15 middle area test points exhibiting a matrix distribution). The density deviation of each region of the board material was obtained by detecting the density in these regions. Other test methods were conducted in reference to the test methods in the national standard "Test Methods for the Physicochemical Performance of Artificial Boards and Finished Artificial Boards" - GB / T 17657-2013, and the measurement results are shown in Table 4.

[0034] [Table 4] Note: RSD = SD / X, where SD represents the standard deviation and X represents the mean.

[0035] According to the test results, first, based on the results of the surface density uniformity test of Examples 1-7, in the manufacturing method of Examples 1-7, the crushed wood fiber powder and lime milk were uniformly mixed in a constant ratio beforehand, and finally a wet material compaction process was adopted, resulting in a small particle size of crushed wood fiber powder. After the final density uniformity test, the density difference between the surface and edge of the board material was small, and the difference between the maximum density of the board surface and the minimum density of the board material edge was small. Furthermore, the mixing process of the primary crushed wood fiber agitated mixture material, the ratio of crushed wood fiber powder to lime milk, or the adjustment of the mesh count of the crushed wood fiber powder can all affect the surface density uniformity. Next, as can be seen by comparing the test results of Examples 1-7 and Comparative Example 1, the mixed material of wood fibers stirred only once in Comparative Example 1 was affected in terms of uniformity of surface density, even assuming that the stirring time was extended to the same extent as the two stirring times in Example 6. If the stirring time was further extended to improve the uniformity of surface density, it would affect the quantitative production efficiency. The mixed material of primary wood fibers in Example 1-7 had a more uniform distribution of PVB particles and exhibited even better uniformity of surface density. Thirdly, as can be seen by comparing the test results of Examples 1-7 and Comparative Example 2, the wood fibers in Comparative Example 2, which only used a PVB interlayer and were not subjected to grinding and crushing treatment (wood particle size was 5 cm), also showed a slightly worse effect on uniformity of surface density than Example 1-7. Moreover, Example 1-7 is more compatible with the quantitative production technology of the production line and has a cost advantage as lime milk is used as an inorganic adhesive. Fourth, as can be seen by comparing the test results of Examples 1-7 and Comparative Example 3, in Comparative Example 3, the parameters related to the high-frequency heating temperature, processing time, and moisture content of the wood fiber prefabricated board obtained after pressurizing each time during the consolidation step were adjusted, and as can be seen, the effect on the uniformity of the board surface density was not as significant as in Examples 1-7. Finally, as can be seen by comparing Examples 1-2 and 5-7, both of which used poplar fiber powder, the consolidation step also has a certain effect on the uniformity of the board surface density.

[0036] (Test Example 2) Test for Uniformity of Cross-sectional Density of Board Material The purpose of the test is to compare the uniformity of the cross-sectional density of the board material by manufacturing the test example's crushed wood fiber compacted board material according to the methods of Examples 1-7 and manufacturing the comparative example's crushed wood (fiber) compacted board material according to the manufacturing method of Comparative Example 1-3.

[0037] The test method involved using compressed wood fiber boards manufactured according to the manufacturing methods of Examples 1-7 and Comparative Examples 1-3, with each sample having the same length, width, and height (i.e., 1220mm*2440mm*12mm). The specific test method was carried out in reference to the test method in the "Method for Measuring Cross-sectional Density of Artificial Boards" -LY / T 2718-2016, a standard of the Forestry Industry of the People's Republic of China, and the measurement results are shown in Table 5.

[0038] [Table 5]

[0039] According to the test results, first, the cross-sectional density uniformity test results for Examples 1-7 show that the wood fiber compacted board manufactured using the material mixing step, molding step, compaction step, and curing step of the manufacturing method in Example 1-7 has excellent cross-sectional density uniformity. Next, as can be seen by comparing the test results of Examples 1-7 with Comparative Examples 1 and 3, Comparative Example 1 changed the material mixing step, and Comparative Example 3 changed the compaction step, both of which may affect the cross-sectional density uniformity. Furthermore, comparing Example 1-7 with Comparative Example 2, while the RSD of density uniformity for each layer (including the wood board layer, wood block layer, and wood board layer) in Comparative Example 2 is only 0.017, a comparison of the wood block layer alone using a cross-sectional density uniformity test shows that the comparison results are not superior to the effect of Example 1-7. Finally, as can be seen by comparing Examples 1-2 and 5-7, both of which use poplar fiber powder, the conditions of the compaction step have a certain effect on the cross-sectional density uniformity of the board material. Examples 8-10

[0040] Examples 8-10 provide a method for manufacturing a flame-retardant crushed wood fiber compacted board (also called a fire-resistant crushed wood fiber compacted board). This method includes all the steps of Example 6, but differs in that it further adds light-calcined magnesium oxide and magnesium chloride to the primary crushed wood fiber agitated mixture and mixes them uniformly to obtain a secondary crushed wood fiber agitated mixture. The specific amounts used are shown in Table 6.

[0041] [Table 6] Example 11

[0042] This embodiment provides a flame-retardant wood fiber compacted board, and the quantitative production method for the wood fiber compacted board includes all the steps of Example 8, the only difference being the addition of 55 parts lime milk and 5 parts magnesium hexahydrate (halogen chips). Example 12

[0043] This embodiment provides a compacted wood fiber board, and the quantitative production method for the compacted wood fiber board comprises all the steps of Example 8, the only difference being the use of 60 parts of lime milk and 5 parts (240 mesh) of magnesium hexahydrate (halogen chips). Comparative Example 4

[0044] In the material mixing step, instead of lime milk, 3 parts alumina sol, 5 parts water glass, and 8 parts deionized water are used, and the other quantitative production method of crushed wood fiber compacted board is the same as in Example 9. Comparative Example 5-6

[0045] The consolidation steps for Comparative Examples 5-6 are shown in Table 7, and other parameters not shown are the same as those for Example 9.

[0046] [Table 7] Comparative Example 7

[0047] In the material mixing step, polyvinyl alcohol is used instead of PVB particles, and the other methods for the quantitative production of wood fiber compacted boards are the same as in Example 9. Comparative Example 8

[0048] The method of Example 2 in Chinese Patent CN1094351A is adopted, and among them, In the mixing step of the materials, 4 kg of magnesium chloride is prepared with water to a Baumé degree of 28 degrees, 4 kg of crushed water binder is dissolved in water by boiling, 3 kg of slaked lime, 3 kg of white sugar, and an equal amount of water are heated and boiled, stirred, and then left to stand for 4 days, 8 kg of magnesium oxide and 23 kg of straw waste are mixed, and the above-produced material is heated with steam and stirred, In the molding step, the material is placed in a mold sprinkled with waterproof insulation powder when heated to 80°C, and during the process, bamboo reinforcing bars are laid in layers vertically and horizontally, and the waterproof insulation powder is evenly sprinkled on the surface of the material. In the compaction step, after vibration, a hydraulic press is used to compress the area by 30 kg / cm². 2 Then, press and seal. In the finishing step, the material was cured by heat retention and then demolded and dried.

[0049] (Test Example 3) Test for uniformity of surface density of board material Referring to the method in Test Example 1, the wood fiber compacted boards for each test example were manufactured based on the methods in Examples 8-10, and the uniformity of the board surface density was tested. The measurement results are shown in Table 8.

[0050] [Table 8]

[0051] According to the test results, the density uniformity test results for the board surface of Examples 8-10 showed that in the manufacturing method of Examples 8-10, the crushed wood fiber powder and lime milk were uniformly mixed in a constant ratio beforehand, and a wet material compaction process was finally adopted, resulting in a small particle size of crushed wood fiber powder. After the final density uniformity test, the density difference between the board surface and the board edge was small, and the difference between the maximum density of the board surface and the minimum density of the board edge was small. Thus, Examples 8-10 guaranteed its flame retardant effect, and although slightly inferior to the effect of Examples 5-7, it still had a significant advantage in terms of density uniformity of the board compared to other comparative examples.

[0052] (Test Example 4) Test for Uniformity of Cross-Sectional Density of Board Material Refer to the method in Test Example 2, and manufacture the wood fiber compacted boards for each of the test examples based on the methods in Examples 8-10. Test the uniformity of the cross-sectional density of the boards, and refer to Table 9 for the measurement results.

[0053] [Table 9]

[0054] According to the test results, the cross-sectional density uniformity test results for Example 8-10 indicate that Example 8-10 has excellent cross-sectional density uniformity, demonstrating that the sheet material achieves both flame retardancy and a more uniform density, resulting in a more stable structure.

[0055] (Test Example 5) Combustion test of compressed wood fiber board Compressed wood fiber boards were manufactured using the manufacturing methods of Examples 8-12 and Comparative Example 4, and combustion tests were conducted according to the method specified in GB8624-2012. The test results are shown in Table 10.

[0056] [Table 10] Note: PCS indicates the total heat generation value, FIGRA 0.2MJ This indicates the combustion growth rate index, THR 600s This indicates the total heat dissipation within 600 seconds.

[0057] As can be analyzed from the test results, all of Examples 8-12 meet the Class A standard specified in GB8624-2012. Of these, the wood fiberboard produced using the manufacturing method of Example 9 had a combustion performance closer to Class A1. On the other hand, according to the test results of Comparative Example 4, some indicators of the combustion performance of the board did not reach Class A. Compared with Examples 8-12, Comparative Example 4 used 3 parts alumina sol, 5 parts water glass, and 8 parts deionized water as an inorganic adhesive instead of lime milk. The comparative results show that this conversely affected the combustion performance of the board. Therefore, this application explains that the application does not simply select lime milk and use it as an adhesive, but rather that by adjusting the lime milk and its addition ratio and concentration, it combines with magnesium chloride and magnesium oxide in different proportions, creating conditions that affect the combustion performance of the board.

[0058] (Test Example 6) Testing the uniformity of screw gripping force in different regions and the screw gripping force of different lots. Compressed wood fiber boards were manufactured according to the methods of Examples 8-10, and compared with the manufacturing method of Comparative Examples 5-6. The test compressed wood fiber boards manufactured according to the methods of Examples 8-10 and Comparative Examples 5-6 all had the same length, width, and height, i.e., 1220mm*2440mm*12mm. Three lots of boards were manufactured for each method, and the uniformity of the screw gripping force in different areas of the same board was measured. Stability tests of the screw gripping force were also performed on boards from different lots. This determined whether the deviation of the screw gripping force at different positions on the same board was too large and whether the screw force of boards from different lots manufactured using the same method was stable. The specific test methods were conducted in reference to the test methods in the national standard "Test Methods for the Physicochemical Performance of Artificial Boards and Finished Artificial Boards" - GB / T 17657-2013, and the measurement results are shown in Table 11.

[0059] [Table 11]

[0060] According to the test results, both Examples 8-10 and Comparative Examples 5-6 employed three high-frequency heating and pressurizing process steps. The difference between Examples 8-10 and Comparative Examples 5-6 is that Examples 8-10 employed different high-frequency heating temperatures and processing times. As can be seen from the comparison, the crushed wood fiber compacted boards produced based on Examples 8-10 showed a smaller difference in screw gripping force values ​​between the board edge and board surface within the same board material. The screw gripping force at each position on the board surface was more uniform and stable, and the screw gripping force at the board surface or edge was stronger compared to Comparative Examples 5-6, making them more suitable for industrial quantitative production. This explains that adjusting the high-frequency heating temperature and processing time is one of the indicators that affects the uniformity of screw gripping force in crushed wood fiber compacted board material. Experimental Example 7

[0061] Formaldehyde emissions Based on the manufacturing method of Example 9, one set of compressed wood fiber boards for the experiment was manufactured. The length, width, and height of the boards in test sets 1-3 were all the same, measuring 2m x 1.2m x 0.5m each. They were particleboards of the same area purchased from Shandong Linyi Guangze Board Factory. Test set 1 and the particleboard were measured in 10m². 2 The samples were left in a room, temperature-controlled at 60°C, sealed, and left for 15 days. Formaldehyde emissions from the wood were detected using a formaldehyde detection device, and the results of formaldehyde emission detection for each test group of wood are shown in Table 12.

[0062] [Table 12] According to the test results, the flame-retardant crushed wood fiber compacted board material manufactured using the manufacturing method of the present invention does not emit formaldehyde.

[0063] (Test Example 8) Physical Performance Test The wood fiber compressed boards produced by the manufacturing methods of Examples 8-10 and Comparative Examples 7 and 8 were subjected to physical performance tests in accordance with the "Physicochemical Performance Test Methods for Artificial Boards and Finished Artificial Boards, National Standard GB / T 17657-2013 of the People's Republic of China," and the test results are shown in Table 13.

[0064] [Table 13]

[0065] The results showed that the physical performance indicators of the wood fiber compacted boards of Examples 8-10 were superior to those of Comparative Examples 7 and 8, and among them, the physical performance indicators of some of the wood fiber compacted timber produced by the manufacturing method of Example 9 were superior to those of Comparative Examples 7 and 8 and the manufacturing methods of the other examples. Compared to Comparative Example 7, Example 9 replaced polyvinyl alcohol with PVB particles, and the resulting test results showed that it improved at least the static folding strength and load indicators. Therefore, it demonstrates that adopting PVB particles and correspondingly adjusting their particle size can affect some of the physical properties of the sheet material. Compared to Comparative Example 8, Examples 8-10 are similar fireproof board materials and employ some similar components, but there are differences in their manufacturing methods. For example, the manufacturing method of Example 9 first employs a method of producing a primary crushed wood fiber agitated mixture material, controlling the mixing ratio of crushed wood fiber powder and lime powder, the concentration of lime powder, optimizing the mesh count of the crushed wood fiber powder, the particle size of PVB, the addition ratio of magnesium oxide and magnesium chloride, the fineness of the magnesium oxide powder and magnesium chloride powder, and further controlling the high-frequency heating and pressurizing conditions. The method employed in Comparative Example 8 involves melting a water binder, boiling slaked lime in water, letting it stand for 3-4 days, then mixing it with magnesium oxide and wood chips, heating, pressing, heat curing, cooling, and finally demolding and drying. As the name suggests, this process is simple and low-cost, but some of its physical performance is slightly inferior compared to Examples 8-10.

[0066] The embodiments described above are solely for illustrating preferred embodiments of the present invention and do not limit the scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the present invention, provided they do not deviate from the spirit of the design of the invention, should all be included within the scope of protection defined in the claims of the present invention.

Claims

1. The process involves a mixing step of materials, in which 55-80 parts by weight of crushed wood fiber powder and 40-60 parts by weight of lime milk are uniformly mixed to obtain a primary crushed wood fiber mixed material, and the primary crushed wood fiber mixed material and 8-12 parts by weight of resin particles are uniformly mixed to obtain a secondary crushed wood fiber mixed material. The molding step involves placing the aforementioned secondary crushed wood fiber agitated mixture into a mold, molding it, and then demolding it to obtain a crushed wood fiber prefabricated board. The aforementioned prefabricated wood fiber board is subjected to high-frequency heating and pressurization to obtain a semi-finished product of a compressed wood fiber board, a compaction step in which the prefabricated wood fiber board is subjected to high-frequency heating and pressurization, The process includes a finishing step of lowering the temperature of the semi-finished product of the crushed wood fiber compacted board and curing it to obtain the crushed wood fiber compacted board, A method for quantitatively producing compressed wood fiber boards, characterized by the following features.

2. The method according to claim 1, characterized in that, in the stirring step of the materials, after obtaining the primary wood fiber stirring mixture, the primary wood fiber stirring mixture is uniformly stirred with 8-12 parts by weight of resin particles, 20-40 parts by weight of magnesium oxide, and 3-5 parts by weight of magnesium chloride to obtain a secondary wood fiber stirring mixture.

3. The method according to the present invention, characterized in that the wood fiber powder has a mesh count of 180 to 300 mesh, and the lime milk, magnesium oxide, and magnesium chloride are each added after being sieved to a mesh count of 100 to 240 mesh.

4. The method according to any one of claims 1 to 2, characterized in that the particle size of the resin particles is 0.03-0.05 mm.

5. The method according to any one of claims 1 to 2, characterized in that the resin comprises one or more ethylene-vinyl acetate copolymers or polyolefin materials, the polyolefin material is a mixture of one or at least two polyethylene, polypropylene, modified polyethylene, modified polypropylene, or ethylene elastomers containing ethylene units, and the modified polyethylene comprises polyvinyl butyral resin (PVB), polyvinyl chloride resin (PVC), and polyvinyl formal (PVF).

6. The method according to any one of claims 1 to 2, characterized by performing a pre-pressing treatment on a mixed material of secondary crushed wood fibers before or after demolding to obtain a prefabricated board of crushed wood fibers with a moisture content of 35%-40%.

7. The aforementioned consolidation step is, The first step involves subjecting the aforementioned prefabricated wood fiber board to a first heat-pressure treatment to obtain a prefabricated wood fiber board with a moisture content of 29%-32%, wherein the treatment temperature for the first heat-pressure treatment is 80-90°C and the treatment time is 1-10 min. The first heat-pressure treated prefabricated wood fiber board is subjected to a second heat-pressure treatment to obtain a prefabricated wood fiber board with a moisture content of 15%-19%, the treatment temperature for the second heat-pressure treatment being 90-100°C and the treatment time being 1-5 min, and The method according to any one of claims 1 to 2, characterized by comprising the step of subjecting the wood fiber prefabricated board subjected to the second heat-pressure treatment to a third heat-pressure treatment to obtain a wood fiber prefabricated board subjected to a third heat-pressure treatment with a moisture content of 8%-15%, wherein the wood fiber prefabricated board subjected to the third heat-pressure treatment is a semi-finished product of the wood fiber compacted board, the treatment temperature for the third heat-pressure treatment is 150-180°C, and the treatment time is 1-3 min.

8. The method according to claim 7, characterized in that, in the consolidation step, the first compression ratio is 35%-40%, the second compression ratio is 45%-55%, and the third compression ratio is 60%-70%.

9. The method according to any one of claims 1 to 2, characterized in that the wood fiber powder comprises at least one of low-quality wood fiber powder and fruit tree branch and bud fiber powder.

10. A wood fiber compacted board characterized by being manufactured based on the quantitative production method for wood fiber compacted board described in any one of claims 1 to 9.

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