Groundwood fiber compacted board and its quantitative production method

Abstract

A groundwood fiber compacted board and a method for quantitatively producing the same are provided. [Solution] A method for quantitatively producing ground fiber boards, which involves uniformly stirring 55-80 parts by weight of ground wood fiber powder and 40-60 parts by weight of lime milk to obtain a primary ground fiber stirred and mixed material, uniformly stirring the primary ground fiber stirred and mixed material with 8-12 parts by weight of resin particles to obtain a secondary ground fiber stirred and mixed material, pouring the secondary ground fiber stirred and mixed material into a mold and molding it, and then demolding it to obtain a ground fiber prefabricated board, subjecting the ground fiber prefabricated board to high-frequency heating and pressure treatment to obtain a semi-finished ground fiber consolidated board, and cooling the semi-finished ground fiber consolidated board and curing it to obtain a ground fiber consolidated board.

Description

[Technical Field]

[0001] The present invention belongs to the field of groundwood hot-pressed board technology, and particularly relates to a groundwood fiber compacted board and a method for its quantitative production. [Background technology]

[0002] Hot-pressed groundwood boards offer the advantages of being able to utilize various types of groundwood and being low cost, while also fully utilizing the functions of wood. They are therefore increasingly valued by manufacturers of log boards that generate large amounts of groundwood. By using additives, hot-pressed groundwood boards can achieve sound insulation, thermal insulation, moisture resistance, antiseptic and mildew resistance, and fire and flame retardancy. Hot-pressed groundwood boards with fire and flame retardancy have the widest range of applications. However, conventional technologies struggle to achieve both physical processing performance and flame retardancy, while also struggling to balance mass production and cost. Patent Document 1, a series of Chinese patents entitled "high-frequency compaction technology," discloses a method for manufacturing nut compaction boards based on high-frequency technology. The nut compaction boards have excellent processing and moisture resistance properties and retain the distinctive nut aroma. The composite material, made from nut scraps and PVB resin particles, and the PVB interlayer are manufactured through a pre-compacting process, followed by heating and pressing, and cutting and polishing. When PVB resin fiber particles and a PVB interlayer are mixed, better water absorption thickness expansion performance is achieved under appropriate high-frequency hot pressing conditions. However, the use of a PVB interlayer generally requires a long laying time, and large-scale production requires high equipment requirements. Patent Document 2 discloses a method for manufacturing a densified wood fireproof board using high-frequency technology, which involves laminating a pre-treated wood board with a first flame-retardant film, a second flame-retardant film, and a third flame-retardant film made with different flame retardants. However, this method is not suitable for producing hot-laid groundwood boards because it uses wood boards as raw materials and the flame-retardant films are expensive. Patent Document 3 discloses a densified wood material and method using high-frequency adhesiveless compaction technology, which employs steps such as dry mixing of resin particle materials, laying of resin film pieces, and two hot-laid compactions to produce a laboratory-scale multi-layer densified wood board. The densified wood material of this patent includes a wood board layer and a densified groundwood layer, and the lamination step requires an artificial PVB interlayer, making automated production difficult. Therefore, there is a need in the art for a groundwood fiber compacted board that can be mass-produced and has excellent physical properties and fire 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 Summary of the Invention [Problem to be solved by the invention]

[0004] To address the above technical problems, the present invention provides a number of types of groundwood compacted boards and a method for quantitatively producing groundwood compacted boards, and the main technical solutions are as follows: [Means for solving the problem]

[0005] In a first aspect of the present invention, there is provided a method for the quantitative production of groundwood fibre compacted boards, comprising: a mixing step of uniformly mixing 55-80 parts by weight of ground wood fiber powder and 40-60 parts by weight of lime milk to obtain a mixed material of primary ground wood fiber, and uniformly mixing the mixed material of primary ground wood fiber with 8-12 parts by weight of resin particles to obtain a mixed material of secondary ground wood fiber; The mixed material of the secondary ground wood fiber is put into a mold to be molded, and after demolding, a ground wood fiber prefabricated board is obtained; A consolidation step of subjecting the groundwood fiber prefabricated board to high-frequency heating and pressure treatment to obtain a semi-finished product of a groundwood fiber consolidated board; and a processing step of cooling the semi-finished product of the groundwood fiber board and curing it to obtain the groundwood fiber board.

[0006] The second aspect of the present invention provides a quantitative production method for fire-retardant groundwood compacted board, which differs from the first aspect in the following respects: in the mixing step of the materials, after obtaining the mixed material of primary groundwood fiber, the mixed material of primary groundwood fiber is uniformly mixed 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 the mixed material of secondary groundwood fiber. [Effects of the Invention]

[0007] The beneficial effects of this invention are as follows. First, in the material mixing step of the quantitative groundwood compaction board production method, the dry material mixing used in the prior art is changed to wet material mixing using lime milk and groundwood powder, followed by the addition of resin particles. The resin film is omitted. The compaction step involves three heating and pressing treatments, with the moisture content and treatment time after each heating and pressing being limited. This results in similar physical properties between mass-produced and laboratory-produced boards. Furthermore, this method enables the quantitative production of groundwood compaction boards with balanced physical properties, with a significant improvement in the uniformity of the screw gripping force of the resulting boards. Finally, the addition of magnesium oxide, magnesium chloride, etc. after the primary groundwood compaction material mixing process achieves the synergistic flame retardant effect of the magnesium-based flame retardant and inorganic adhesive, significantly improving the flame retardant performance of the groundwood compaction board. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following examples further illustrate the present invention but should not be construed as limiting it. Any modifications or substitutions to the methods, steps, or conditions of the present invention that do not depart from the spirit and substance of the present invention are within the scope of the present invention.

[0009] Some embodiments of the present invention provide a method for manufacturing a groundwood fiber compacted board, which includes the steps of mixing, shaping, compacting, and regulating the material. During the ingredient mixing step In the material stirring step of the present invention, the groundwood fiber powder and the auxiliary materials are mixed and stirred to finally obtain a groundwood fiber mixed material.

[0010] The ground wood fiber powder of the present invention is prepared by grinding and pulverizing ground wood, such as low-quality wood and fruit tree buds, into fine wood fiber powder with a mesh size of 180 mesh (particle size of approximately 0.088 μm) to 300 mesh (particle size of 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 mortar-type roller mill, vertical mill, multi-layer vertical mill, vertical roller mill, disc mill, DMC mill, etc. The low-quality wood includes fast-growing woods such as poplar, eucalyptus, cedar, and willow, and the cedar includes willow cedar, water cedar, and cloud cedar. The fruit tree buds include growing branches, fruiting branches, and fruiting mother branches of apple, pear, and peach. Equipment for processing ground wood further includes, but is not limited to, a wood chipper, a wood crusher, etc. Equipment for mixing and stirring ground wood fiber powder and auxiliary materials includes, but is not limited to, a stirrer, a material mixer, etc. The power of the material mixer is 40-45KW, and the stirring speed is 25 rpm. The stirring time is not particularly limited and can be determined according to the actual stirring conditions of the materials.

[0011] The resin of the present invention includes one or more of ethylene-vinyl acetate copolymer (EVA) or polyolefin-based materials, and the polyolefin-based materials are one or a mixture of at least two of polyethylene, polypropylene, modified polyethylene, modified polypropylene, and 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 Meibon 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 includes one or more of a phosphorus-based flame retardant, a metal compound flame retardant, a nitrogen-based flame retardant, a boron-based flame retardant, a nitrogen-phosphorus flame retardant, and a magnesium-based flame retardant. The phosphorus-based flame retardant includes an organic phosphorus-based flame retardant and an inorganic phosphorus-based flame retardant, and the organic phosphorus-based flame retardant includes 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-based flame retardant includes one or more of ammonium dihydrogen phosphate, ammonium polyphosphate, guanidine nitrogen phosphorus phosphate, and diammonium hydrogen phosphate. The magnesium-based flame retardant includes one or more of magnesium hydroxide, light-burned magnesium oxide (magnesium oxide), magnesium chloride, and magnesium chloride hexahydrate (halogen chips), and the magnesium hydroxide includes nanoscale magnesium hydroxide fiber, nanoscale magnesium hydroxide sheet, and nanoscale magnesium hydroxide polyhedron, of which magnesium chloride and magnesium chloride hexahydrate (halogen chips) are also used as hardeners.

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

[0014] The auxiliary materials of the present invention, such as the flame retardant, hardener, and lime milk (or quicklime), must be sieved through a 100 to 240 mesh sieve before being added, in order to remove large particles of foreign matter.

[0015] The equipment used to mix the ingredients used in the ingredient mixing step includes, but is not limited to, a stirrer or ingredient mixer.

[0016] In the molding step The molding step of the present invention may be to place a mold frame on the pressing plate of a hot pressing machine, load the stirred and mixed secondary ground wood fiber material into the mold frame, and then clamp the mold. After the shape is stabilized, a pre-pressing process is carried out using a hot pressing machine to obtain a ground wood fiber prefabricated board with a moisture content of 35%-40%. Alternatively, the molding step may be to place a mold frame on the pressing plate of a hot pressing machine, load the stirred and mixed secondary ground wood fiber material into the mold frame, and then clamp the mold. After the shape is stabilized, a pre-pressing process is carried out using a hot pressing machine to obtain a ground 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 conveying piping connected to the outlet position of the agitator or material mixer.

[0018] In a further embodiment of the shaping step, the obtained groundwood fiber prefabricated board can further undergo an edge cutting step or an edge polishing step, where the cutting equipment includes but is not limited to a cutter, and the polishing equipment includes but is not limited to a polisher, to make the edges of the obtained groundwood fiber prefabricated board more neat after cutting.

[0019] In the consolidation step The consolidation step of the present invention involves subjecting the obtained groundwood fiber prefabricated board to a heat and pressure treatment to obtain a semi-finished groundwood fiber board. The consolidation method generally refers to various hot pressing methods under high frequency conditions in Patent Documents 3, 2 and 1.

[0020] The equipment used in the consolidation process is a consolidation machine, and the groundwood prefabricated board may be heated and pressed in the consolidation machine one or more times under the same or different conditions to form a semi-finished groundwood board, or may be heated and pressed one or more times and then further heated and pressed at high frequency to form a semi-finished groundwood board. For information on consolidation equipment, see Patent Documents 4, 5, 6, 7, 8, 9, and 10.

[0021] In the organizing step In the arranging step of the present invention, the semi-finished groundwood fiber board is subjected to a temperature-lowering curing treatment, and then a finished groundwood fiber board is obtained.

[0022] A curing area is set up for the finished groundwood fiber boards. The curing area is a spatial area that is ventilated, dry, maintained at normal temperature, and avoids external interference such as sunlight and rainwater. The curing space is a room of 10-20 square meters. Within the curing area, a certain amount of space is left between the surfaces of the finished groundwood fiber boards. The temperature in the curing area is 28-35°C, and the humidity is controlled at 5%. The surfaces of the groundwood fiber boards are cooled to 50°C and then transferred to the curing space and left for 7-15 days. A ventilation system is set up in the room to ventilate the curing space, and temperature and humidity monitoring equipment is set up in the room to monitor the temperature and humidity of the curing space.

[0023] The manufacturing method of groundwood board provided in an embodiment of the present invention takes a "4:8 foot" groundwood board (width 4 feet (1220 mm), length 8 feet (2440 mm)) as an example. The quantified production efficiency of groundwood board on one production line can reach more than 30 cubic meters per hour, and if the groundwood board is 12 mm thick, it can produce approximately 840 pieces of groundwood board per hour.

[0024] The groundwood fiber board of the present invention can be a substrate, and a decorative layer is applied to the surface.

[0025] The present invention will be further described below with reference to specific examples. In the specific examples, all "parts" refer to "parts by weight" and are converted after taking materials based on weight units such as kilograms (KG). Example 1

[0026] Regarding the material preparation, 55 parts of poplar fiber powder, 40 parts of lime milk, and 8 parts of PVB particles, of which lime milk is a 15% calcium hydroxide suspension, (1) During the mixing step of the ingredients For the primary ground wood fiber agitation mixture, 55 parts of poplar fiber powder and 40 parts of lime milk are uniformly mixed in advance to form a primary ground wood fiber agitation mixture, and then 8 parts of the primary ground wood fiber agitation mixture and PVB particles are uniformly mixed to obtain a secondary ground wood fiber agitation mixture. The material is then transported to the compactor through a material conveying pipe. The PVB is in granular form, the particle size of the PVB particles is 0.03 mm, and the mesh number of the poplar fiber powder is 180 mesh. (2) In the molding step The mixed material of secondary ground wood fiber is placed in a mold and clamped, and after pre-pressing treatment, the mold is released to obtain a ground wood fiber prefabricated board with a moisture content of 35%. (3) In the consolidation step The groundwood fiber prefabricated board is subjected to a first heating and pressing treatment to obtain a first heating and pressing treated groundwood fiber prefabricated board with a moisture content of 29%, the treatment temperature of the first heating and pressing treatment is 80°C, the treatment time is 2 minutes, and the first compression ratio is 40%. The first heat-pressurized groundwood fiber prefabricated board is subjected to a second heat-pressurization treatment to obtain a second heat-pressurized groundwood fiber prefabricated board having a moisture content of 15%, the second heat-pressurization treatment is performed at a temperature of 90°C, the treatment time is 2 minutes, and the second compression ratio is 50%; The second heat-pressurized wood fiber prefabricated board is then subjected to a third heat-pressurization treatment to obtain a third heat-pressurized ground wood fiber prefabricated board with a moisture content of 8%, which is a semi-finished product of ground wood fiber compacted board, the treatment temperature of the third heat-pressurization treatment is 150°C, the treatment time is 2 minutes, and the third compression ratio is 65%; (4) In the sorting step After the cooling treatment, the semi-finished product of the groundwood fiber board was placed in a curing space for 15 days to obtain the groundwood fiber board. Examples 2-4

[0027] Examples 2-4 provide a method for manufacturing a groundwood fiber board, which includes all the steps of Example 1, except for the parameters shown in Table 1. [Table 1] Examples 5-7

[0028] Examples 5-7 provide methods for manufacturing groundwood fiber compacted boards, which include all the steps of Example 2, except for the compaction step, which has the parameters shown in Table 2. [Table 2] Comparative Example 1

[0029] In the material stirring step, 55 parts of poplar fiber powder, 40 parts of lime milk, and 8 parts of PVB particles were stirred uniformly at the same time, and the stirring time was the same as the sum of the two stirring times in Example 6. A ground wood fiber stirred and mixed material was obtained after only one stirring. The other quantitative production methods for ground wood fiber compacted boards were the same as in Example 6. Comparative Example 2

[0030] The method of Example 12 in Chinese Patent CN109834776A was adopted, and ground wood and a PVB interlayer were placed between two adjacent wooden boards, with the mass ratio of the wooden boards to the ground wood blocks being 1:1 and the particle size of the ground wood being 5cm, to produce a laminated wooden board. The laminated wooden board was then subjected to high-frequency heating and pressure treatment to obtain an intermediate-layer ground wood compacted board (including a wooden board layer - a ground wood block layer - a wooden board layer), and the two wooden board layers of the intermediate-layer ground wood compacted board were cut out to obtain a ground wood compacted board. Comparative Example 3

[0031] The process of the consolidation step of Comparative Example 3 is shown in Table 3, and the quantitative production method of the groundwood fiber consolidation board not shown is the same as that of Example 6. [Table 3]

[0032] (Test Example 1) Test of uniformity of sheet metal surface density The purpose of the test was to test the uniformity of the board surface density by manufacturing test example groundwood fiber compacted boards based on the methods of Examples 1-7 and comparing them with comparative example groundwood (fiber) compacted boards manufactured based on the manufacturing methods of Comparative Examples 1-3.

[0033] The test method used groundwood (fiber) compacted boards manufactured according to the manufacturing methods of Examples 1-7 and Comparative Examples 1-3, respectively. The length, width, and height of each set of samples were the same, i.e., 1220mm*2440mm*12mm. The densities of different regions on the edge (five test points on the short side and ten test points on the long side, for a total of 30 edge test points) and middle (15 middle test points distributed in the middle, with a matrix distribution) of the board surface (the surface along the length and width) of the same board were measured to obtain the density deviations of each partial region of the board. Other test methods were performed in accordance with the test methods in the national standard "Testing Methods for the Physicochemical Performance of Artificial Boards and Finished Artificial Boards" - GB / T 17657-2013. The test results are shown in Table 4.

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

[0035] According to the test results, first, the test results of the surface density uniformity of Examples 1-7 show that in the manufacturing method of Examples 1-7, the ground wood fiber powder and milk of lime are mixed uniformly in advance at a certain mixing ratio, and finally a wet material consolidation process is used, and the particle size of the ground wood fiber powder is small. After the final density uniformity test, the density difference between the surface and edge of the board is small, and the difference between the maximum density of the board surface and the minimum density of the board edge is small. In addition, the mixing process of the primary ground wood fiber stirring and mixing material, the mixing ratio of ground wood fiber powder and milk of lime, or the adjustment of the mesh number of the ground wood fiber powder can all affect the surface density uniformity. Next, comparing the test results of Examples 1-7 and Comparative Example 1, it can be seen that the ground wood fiber mixed material mixed only once in Comparative Example 1 affects the uniformity of the board surface density, even if the single mixing time is extended to the same extent as the two mixing times in Example 6. If the mixing time were extended further to improve the board surface density uniformity, it would affect the quantified production efficiency. The primary ground wood fiber mixed material in Examples 1-7 achieves more uniform PVB particle distribution and has even better board surface density uniformity. Third, comparing the test results of Examples 1-7 and Comparative Example 2, it can be seen that the ground wood in Comparative Example 2, which uses only a PVB interlayer and is not ground and crushed (ground wood particle size is 5 cm), also has a slightly worse effect on the board surface density uniformity than Examples 1-7. Furthermore, Examples 1-7 are more compatible with the quantified production technology of the production line and have a cost advantage by using lime milk as an inorganic adhesive. Fourth, comparing the test results of Examples 1-7 and Comparative Example 3, it can be seen that in Comparative Example 3, the parameters related to the high-frequency heating temperature, processing time, and moisture content of the groundwood fiber prefabricated board obtained after each pressurization were adjusted three times in the consolidation step, and it can be seen that the effect on the uniformity of the board surface density is not as good as in Examples 1-7. Finally, comparing Examples 1-2 and 5-7, both of which use poplar fiber powder, it can be seen that the consolidation step also has a certain effect on the uniformity of the board surface density.

[0036] (Test Example 2) Test of uniformity of plate cross-sectional density The purpose of the test was to test the uniformity of the board cross-sectional density by manufacturing test example groundwood fiber compacted boards based on the methods of Examples 1-7 and comparing them with comparative example groundwood (fiber) compacted boards manufactured based on the manufacturing methods of Comparative Examples 1-3.

[0037] The test method used groundwood fiber boards manufactured according to the manufacturing methods of Examples 1-7 and Comparative Examples 1-3, respectively. The length, width and height of each set of samples were the same, i.e., 1220mm*2440mm*12mm. The specific test method was performed in accordance with the test method in the Forestry Industry Standard of the People's Republic of China, "Method for Determining the Cross-Sectional Density of Artificial Boards" - LY / T 2718-2016, and the test results are shown in Table 5.

[0038] [Table 5]

[0039] The test results showed that Examples 1-7, which were manufactured using the mixing, molding, compaction, and curing steps of Examples 1-7, had excellent sectional density uniformity. Comparing the test results of Examples 1-7 with Comparative Examples 1 and 3, it was found that Comparative Example 1 changed the mixing step, and Comparative Example 3 changed the compaction step, both of which may affect the sectional density uniformity. Furthermore, when Examples 1-7 were compared with Comparative Example 2, it was found that the RSD of the density uniformity of each layer (including the wood board layer, groundwood block layer, and wood board layer) in Comparative Example 2 was only 0.017. However, when the groundwood block layer was compared separately in a sectional density uniformity test, the results were not superior to those of Examples 1-7. Finally, comparing Examples 1-2 and 5-7, both of which used poplar fiber powder, it was found that the compaction step conditions had a certain effect on the sectional density uniformity of the board. Examples 8-10

[0040] Examples 8-10 provide a method for producing a ground wood fiber board with flame retardant properties (also called fire-resistant ground wood fiber board), which includes all the steps of Example 6, except that light-burned magnesium oxide and magnesium chloride are further added to the stirred and mixed material of primary ground wood fiber, and then stirred uniformly to obtain a stirred and mixed material of secondary ground wood fiber, and the specific amounts used are the parameters shown in Table 6.

[0041] [Table 6] Example 11

[0042] This example provides a fire-retardant groundwood board, and the quantitative production method for the groundwood board includes all the steps of Example 8, except that it contains 55 parts of lime milk and 5 parts of magnesium chloride hexahydrate (halogen chips). Example 12

[0043] This example provides a groundwood fiber board, and the quantitative production method of the groundwood fiber board includes all the steps of Example 8, except that it uses 60 parts of lime milk and 5 parts of magnesium chloride hexahydrate (halogen chips) (240 mesh). Comparative Example 4

[0044] In the mixing step of the materials, 3 parts of alumina sol, 5 parts of water glass, and 8 parts of deionized water were used instead of lime milk, and the other quantitative production methods of the groundwood fiber compacted board were the same as those in Example 9. Comparative Example 5-6

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

[0046] [Table 7] Comparative Example 7

[0047] In the material mixing step, polyvinyl alcohol was used instead of PVB particles, and the other quantitative production methods of groundwood compacted board were the same as in Example 9. Comparative Example 8

[0048] The method of Example 2 in Chinese Patent CN1094351A is adopted, in which: In the material mixing step, 4 kg of magnesium chloride is mixed with water to a Baume degree of 28 degrees, 4 kg of crushed water binder is boiled and dissolved in water, 3 kg of slaked lime, 3 kg of white sugar, and an equal amount of water to the slaked lime are heated and boiled, stirred, and then left to stand for 4 days, and then 8 kg of magnesium oxide and 23 kg of straw scraps are mixed, and the above-mentioned material is heated with steam and stirred. In the molding process, the bamboo is heated to 80℃ and then placed in a mold coated with waterproof and heat-insulating powder. During this process, the bamboo fibers are laid out in layers, vertically and horizontally, and the waterproof and heat-insulating powder is evenly spread on the surface of the material. In the consolidation step, after vibration, a hydraulic press was used to compress the material at 30 kg / cm 2 Press with In the final step, the product was cured by keeping it at a high temperature, and then released and dried.

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

[0050] [Table 8]

[0051] According to the test results, the test results of the board surface density uniformity of Examples 8-10 show that in the manufacturing method of Examples 8-10, the ground wood fiber powder and lime milk are mixed uniformly in advance at a certain ratio, and finally a wet material consolidation process is used, and the particle size of the ground wood fiber powder is small. After the final density uniformity test, the density difference between the board surface and the board edge is small, and the difference between the maximum density of the board surface and the minimum density of the board edge is small. This guarantees the flame retardant effect of Examples 8-10, and although the effect is slightly inferior to that of Examples 5-7, it still has a significant advantage in the board density uniformity compared to other comparative examples.

[0052] (Test Example 4) Plate cross-sectional density uniformity test Referring to the method of Test Example 2, the groundwood fiber compacted boards of the test examples were manufactured according to the methods of Examples 8-10, and the cross-sectional density uniformity of the boards was tested. The measurement results are shown in Table 9.

[0053] [Table 9]

[0054] According to the test results, the cross-sectional density uniformity test results of Examples 8-10 show that Examples 8-10 have excellent cross-sectional density uniformity, and the plates have both flame retardant performance and more uniform density, resulting in a stable structure.

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

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

[0057] As can be seen from the analysis of the test results, all of Examples 8-12 meet the A-grade standard specified in GB8624-2012. Among them, the groundwood fiberboard manufactured using the manufacturing method of Example 9 has a combustion performance that is closer to A1-grade. On the other hand, the test results of Comparative Example 4 show that some of the combustion performance indicators of the board do not reach A-grade. Compared with Examples 8-12, Comparative Example 4 uses 3 parts alumina sol, 5 parts water glass, and 8 parts deionized water as an inorganic adhesive instead of milk of lime. The comparison results show that this actually affects the combustion performance of the board. This explains that the present application does not simply select milk of lime and use it as an adhesive, but that Examples 8-10 adjust the proportion and concentration of milk of lime and its addition to combine with magnesium chloride and magnesium oxide in different mixing ratios, thereby creating conditions that affect the combustion performance of the board.

[0058] (Test Example 6) Testing the uniformity of screw gripping force in different areas and the screw gripping force of different lots The groundwood boards were manufactured according to the methods of Examples 8-10 and compared with the groundwood boards manufactured according to the manufacturing methods of Comparative Examples 5-6. The test groundwood boards manufactured according to the methods of Examples 8-10 and Comparative Examples 5-6 all had the same length, width, and height, namely, 1220mm*2440mm*12mm. Three batches of boards were manufactured using each method, and the uniformity of the screw gripping force in different areas of the same board was measured. The screw gripping force stability tests were also conducted on the different batches of boards to determine whether the screw gripping force deviations in different positions of the same board were too large and whether the screw gripping force of different batches of boards manufactured using the same method was stable. The specific test methods were based on the test methods in the national standard "Testing Methods for Physicochemical Performance of Artificial Boards and Finished Artificial Boards" - GB / T 17657-2013, and the test results are shown in Table 11.

[0059] [Table 11]

[0060] The test results show that Examples 8-10 and Comparative Examples 5-6 all use three high-frequency heating and pressurizing process steps. Compared with Comparative Examples 5-6, the difference between Examples 8-10 and Comparative Examples 5-6 is that Examples 8-10 use different high-frequency heating temperatures and treatment times. From the comparison, it can be seen that the groundwood compacted boards produced according to Examples 8-10 have a smaller difference in the screw gripping force values ​​on the side and surface of the same board material, the screw gripping force at each position on the board surface is more uniform and stable, and the screw gripping force on the surface or side is stronger than that of Comparative Examples 5-6, making them more suitable for industrial quantified production. This demonstrates that adjusting the high-frequency heating temperature and treatment time is one of the indicators that affect the uniformity of the screw gripping force of groundwood compacted boards. Experimental Example 7

[0061] Formaldehyde emissions According to the manufacturing method of Example 9, a set of experimental groundwood compacted boards was manufactured. The length, width and height of the boards in test sets 1-3 were all the same, 2m*1.2m*0.5m, respectively. They were particle boards with the same area purchased from Shandong Linyi Guangze Board Factory. Test set 1 and the particle board were separated into 10m 2 The test pieces were left in a room at 60°C, sealed and left for 15 days, and the formaldehyde emissions from the wood were detected using a formaldehyde detection device. The detection results for formaldehyde emissions from the wood of each test set are shown in Table 12.

[0062] [Table 12] Test results show that the fire-retardant groundwood fiber board manufactured by the manufacturing method of the present invention does not emit formaldehyde.

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

[0064] [Table 13]

[0065] The results show that the physical performance indexes of the groundwood fiber densified boards of Examples 8-10 are superior to those of Comparative Examples 7 and 8, and some physical performance indexes of the groundwood fiber densified boards manufactured by the manufacturing method of Example 9 are superior to those of Comparative Examples 7 and 8 and other Examples. Compared with Comparative Example 7, Example 9 replaces polyvinyl alcohol with PVB particles. The test results show that at least the static folding strength and load indexes are improved. Therefore, it is proved that using PVB particles and adjusting their particle size accordingly may affect some physical properties of the board. Compared with Comparative Example 8, Examples 8-10 are also fireproof board materials and use some of the same ingredients, but there are differences in the manufacturing methods. For example, in the manufacturing method of Example 9, a method is first adopted to manufacture a primary ground wood fiber stirred mixed material, and the mixing ratio of ground wood fiber powder and lime powder, the concentration of lime powder, and the mesh number of ground wood fiber powder, the particle size of PVB, the addition ratio of magnesium oxide and magnesium chloride, and the fineness of magnesium oxide powder and magnesium chloride powder are optimized, and the conditions for high-frequency heating and pressing are also controlled. In Comparative Example 8, the method currently adopted is to melt the water binder, boil the hydrated lime in water, leave it to stand for 3-4 days, then mix it with magnesium oxide and sawdust, heat it, press it, keep it at room temperature and harden it, cool it, and finally demold and dry it. The process method is as expected, the process is simple and low cost, but compared with Examples 8-10, some of its physical properties are slightly inferior.

[0066] The above-described examples are only for illustrating preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the design of the present invention should fall within the scope of protection determined by the claims of the present invention.

Claims

1. a mixing step of uniformly mixing 55-80 parts by weight of ground wood fiber powder and 40-60 parts by weight of milk of lime to obtain a mixed material of primary ground wood fiber, and uniformly mixing the mixed material of primary ground wood fiber with 8-12 parts by weight of resin particles to obtain a mixed material of secondary ground wood fiber; In the step of mixing the materials, after obtaining the mixed material of the primary groundwood fiber, the mixed material of the primary groundwood fiber is uniformly mixed 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 the mixed material of the secondary groundwood fiber; The mixed material of the secondary ground wood fiber is put into a mold to be molded, and after demolding, a ground wood fiber prefabricated board is obtained; A consolidation step of subjecting the groundwood fiber prefabricated board to high-frequency heating and pressure treatment to obtain a semi-finished product of a groundwood fiber consolidated board; The method includes the steps of: lowering the temperature of the semi-finished product of the groundwood fiber compacted board and curing it to obtain the groundwood fiber compacted board; A method for quantitatively producing groundwood fiber compacted boards.

2. 2. The method according to claim 1, wherein the ground wood fiber powder has a mesh number of 180 to 300 mesh, and the milk of lime, the magnesium oxide, and the magnesium chloride are each sieved through a 100 to 240 mesh sieve before being added.

3. 2. The method according to claim 1, wherein the resin particles have a particle size of 0.03-0.05 mm.

4. The method according to claim 1, wherein the resin comprises one or more of an ethylene-vinyl acetate copolymer or a polyolefin-based material, the polyolefin-based material being one or a mixture of at least two of polyethylene, polypropylene, modified polyethylene, modified polypropylene, and an ethylene-based elastomer containing an ethylene unit, and the modified polyethylene comprises polyvinyl butyral resin (PVB), polyvinyl chloride resin (PVC), and polyvinyl formal (PVF).

5. The method according to claim 1, characterized in that the stirred mixed material of secondary groundwood fiber before or after demolding is subjected to pre-pressing treatment to obtain a groundwood fiber prefabricated board with a moisture content of 35%-40%.

6. The consolidation step comprises: the groundwood fiber prefabricated board is subjected to a first heating and pressing treatment to obtain a first heating and pressing treated groundwood fiber prefabricated board having a moisture content of 29%-32%, the first heating and pressing treatment being performed at a temperature of 80-90°C for a treatment time of 1-10 minutes; the first heat-pressurized groundwood prefabricated board is subjected to a second heat-pressurization treatment to obtain a second heat-pressurized groundwood prefabricated board having a moisture content of 15%-19%, the second heat-pressurization treatment being performed at a temperature of 90-100°C for 1-5 minutes; the third heating and pressing process is performed on the second heated and pressed ground fiber prefabricated board to obtain a third heated and pressed ground fiber prefabricated board with a moisture content of 8%-15%, which is the semi-finished ground fiber consolidated board, and the third heating and pressing process is performed at a temperature of 150-180°C for 1-3 minutes.

7. 7. The method according to claim 6, wherein 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%.

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