Method of manufacturing fibreboard
By using wood affected by wood-destroying fungi and a cold-hot pressing method, the method addresses the environmental and energy inefficiencies of traditional fiberboard production, producing high-strength, water-resistant fiberboards with reduced energy costs.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- FEDERALNOE GOSUDARSTVENNOE BYUDZHETNOE OBRAZOVATELNOE UCHREZHDENIE VYSSHEGO OBRAZOVANIYA SIBIRSKIJ GOSUDARSTVENNYJ UNIV NAUKI I TEKHNOLOGIJ IMENI AKADKA M F RESHETNEVA SIBGU IM M F RESHETNEVA
- Filing Date
- 2025-11-27
- Publication Date
- 2026-07-01
AI Technical Summary
Existing methods for producing fiberboards using wood as a raw material face issues such as the use of toxic binders like phenolic resins, which pollute the environment and increase energy consumption, and the need for additional process steps like impregnation and heat treatment, leading to higher production costs and low water resistance.
The method utilizes wood affected by wood-destroying fungi, such as Siberian fir wood infested by Polygraphus proximus Blandford, to produce fiberboards by grinding it into chips, mixing it with mechanically activated wood pulp, and using a cold and hot pressing process without hydrophobic additives or binding resins, optimizing the production process to reduce energy costs and enhance mechanical properties.
This approach results in environmentally friendly fiberboards with improved mechanical strength, water resistance, and reduced energy consumption by eliminating the need for toxic binders and additional processing steps, while maintaining high physical properties.
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Abstract
Description
[0001] The invention relates to a method for producing fiberboards, which includes using wood at various stages of its biodegradation as a raw material to obtain medium-density fiberboards using a wet production method, which can be used to produce structural, heat- and sound-insulating products for construction, as well as to create facing materials and furniture.
[0002] A known method for producing fiberboard (hereinafter referred to as fiberboard) involves using wood as the plant material, ground in an aqueous medium to a fineness of 25 DS. The resulting mass is fed into a mass pit, where an acidic environment is created with a pH of 4.0-4.5 by adding an electrolyte solution. The fiber mass concentration is adjusted to 1.5%. A mat is then formed and dehydrated by forced filtration under vacuum at a pressure of 0.01-0.06 MPa. The mat is then impregnated with a binder of phenolic resins and hydrophobic additives and hot-pressed at 190-210°C and a pressure of 5.0-5.5 MPa. After this, the slabs are additionally heat treated at a temperature of 145-160°C for 3.0-3.5 hours (USSR A.S. N 1381224, MKI B 27 M 3 / 04, 1986).
[0003] The disadvantage of this method is the use of a toxic binder—phenolic resins—which release toxic phenols into the environment, as well as into recycled and wastewater, during high-temperature operations, which has a negative impact on the environment. Furthermore, additional process steps, such as impregnating the carpet with binders and final heat treatment, complicate the process, ultimately leading to increased energy consumption and, ultimately, higher fiberboard production costs.
[0004] A method is known for producing fiberboard (fiberboard) using a wet method, in which wood fiber is obtained by grinding wood chips, after which technological additives are introduced into the fiber mass, then the carpet is cast on the mesh of a casting machine, dehydrated and subjected to hot pressing (see N.Ya. Solechnik “Production of fiberboard”, Moscow, Goslesbumizdat, 1963, pp. 98-102).
[0005] The disadvantage of this method is the use of technological additives, as well as the low water resistance of fiberboard.
[0006] The closest invention to the same purpose is a method for producing fiberboard, which includes obtaining wood fiber by grinding wood chips, introducing phenol-formaldehyde or urea-formaldehyde resin into the wood fiber mass, casting the carpet, dehydrating and hot pressing (Mersov E.D. Production of fiberboards: Textbook for vocational schools - Moscow: Higher school, 1989. - 232 p.: ill.). The disadvantage of the known solution is the insufficient strength and water resistance of the fiberboard.
[0007] The invention solves the problem of producing fiberboard from wood affected by wood-destroying fungi with high physical and mechanical properties and reduced energy costs.
[0008] The technical result consists in reducing energy costs in the production of wood fiber boards due to the use of raw materials with low strength properties.
[0009] The technical result is achieved due to the fact that in the method for producing a wood fiber board, including grinding wood into chips, followed by the production of a semi-finished wood fiber product, the use of waste chips, followed by hydrodynamic processing to obtain wood pulp, casting a wood fiber carpet, cold pressing and hot pressing, according to the invention, wood affected by wood-destroying fungi is used as the starting material, wherein the obtained semi-finished wood fiber product from chips is mixed with wood pulp obtained from waste chips, sifted to a fraction of 5 mm and below, serving as a binder in the following ratio, in wt.%: semi-finished wood fiber product - 70-90, wood pulp - 10-30.
[0010] The raw material used to prepare the semi-finished fibrous product (the basis for obtaining fiberboard (FB)) was chipped mechanically from Siberian fir wood damaged by bark beetle (Polygraphus proximus Blandford) in a stand in the Yemelyanovsky District of Krasnoyarsk Krai. The chippings were then processed into thermomechanical pulp under conditions similar to those used in fiberboard production at the laboratory of the Department of Mechanical Engineering and Wood Processing at M.F. Reshetnev Siberian State University using a scientifically proven design of a fibrillating action grinding set (Vititnev et al., 2018, RU 2652177). The grinding process parameters were as follows: the working gap between the disks was z = 0.1 mm, and the concentration of the fiber pulp was c = 3.6%.
[0011] The feedstock for the preparation of mechanically activated particles was waste from the sorting of wood chips obtained from Siberian fir wood after bark beetle (Polygraphus proximus Blandford) infestation in the same region. Due to the significant degree of wood biodegradation, the production of process chips is characterized by a high yield of substandard fine fractions (up to 65-70%). Processing and mechanical activation of the particles without prior preparation was carried out in a laboratory rotary-pulsation disperser at a concentration of 6% and a processing time of 10 minutes.
[0012] The manufacturing method of fiberboard is as follows:
[0013] Siberian fir wood affected by wood-destroying fungi is ground into chips to a fraction of 1 cm. The chips are fed into a grinding set and processed to the state of a semi-finished wood fiber product. When preparing a fibrous semi-finished product from Siberian fir wood after damage by the bark beetle (Polygraphus proximus Blandford), the fibrillating effect of the grinding set with an increase in the concentration of wood fiber mass during grinding to 3.6% contributes to an increase in the degree of grinding from 38 to 50 DS.
[0014] The weakened structure of intercellular bonds in dead wood promotes effective fiber destruction in the longitudinal direction and their fibrillation during the intense abrasion of fiber bundles and coarse fibers. As a result, the fractional size of the semi-finished product is evened out, with an increased content of thin, long, flexible, fibrillated fibers of the medium fraction and a slight decrease in the coarse and fine fractions. Along with the reinforcing function of the coarse fibers and the filler function of the fine fibers, the values of their L-values a , d a , L a / d a , characterize the functional role in bond formation in the composite material structure. Overall, improving the dimensional and qualitative characteristics of the semi-finished product ensures the production of an environmentally friendly material with an average density of 730 kg / m3. 3 without the use of hydrophobic additives and binding resins.
[0015] Waste wood chips are sorted to a particle size of 5 mm or smaller, after which the fine particles are hydrodynamically processed for 8 minutes. The resulting raw material is mixed in the following ratio (by weight): semi-finished wood fiber – 70-90%, wood pulp – 10-30%.
[0016] After mixing, the carpet is cast, cold pressed to a humidity of 78-80% at a pressure of 1.5 MPa, followed by hot pressing at a pressure of 0.8 MPa for 450 seconds.
[0017] The wood fiber pulp was not sized, and hydrophobic additives and binding resins were excluded. The selected hot pressing mode for producing medium-density composite materials is presented in Table 1.
[0018] Table 1
[0019] Hot Press Mode
[0020] Temperature, tpr, °C Specific pressure (squeezing), Rud, MPa / time, sec Reset to pressure (0.8 MPa), sec Specific pressure (drying), Rud, MPa Cycle time, tвр, sec. 195 1,5 / 10 30 0,8 / 410 450
[0021] Examples of specific implementation of the method for manufacturing fiberboard.
[0022] Example 1.
[0023] Siberian fir wood affected by wood-destroying fungi is ground into chips down to a 1 cm fraction. The chips are fed into a milling unit and processed into semi-finished wood fiber. The chip waste is sorted to a fraction of 5 mm and below, after which the resulting wood pulp is subjected to hydrodynamic processing for 8 minutes. 90% of the semi-finished wood fiber product is mixed with 10% mechanically activated wood pulp (90 grams of semi-finished product, 10 grams of wood pulp). After mixing, the carpet is formed, cold pressed to a moisture content of 78-80% at a pressure of 1.5 MPa, followed by hot pressing at a pressure of 0.8 MPa for 450 seconds.
[0024] Example 2.
[0025] The method is similar to Example 1, with the semi-finished wood fiber product mixed with mechanically activated wood pulp in the following ratio (wt%): 80% semi-finished wood fiber product, 20% mechanically activated wood pulp (semi-finished product 80 grams, mechanically activated wood pulp 20 grams). The boards are formed and tested as in Example 1.
[0026] Example 3.
[0027] The method is similar to Example 1, with the semi-finished wood fiber product being mixed with mechanically activated wood pulp in the following ratio, in wt.%: 70% semi-finished wood fiber product, 30% mechanically activated wood pulp (70 grams semi-finished product, 30 grams wood pulp). Formation and testing of the boards is similar to Example 1.
[0028] The physical and mechanical properties of fiberboard with the replacement of the semi-finished product with mechanically activated mass in proportions of 90 / 10, 80 / 20, 70 / 30 are presented in Table 2.
[0029] Table 2
[0030] Physical and mechanical properties of finished slabs
[0031] Percentage of fiberboard,% σizg, MPa E, MPa ha2, % ha24, % ρ, kg / m3 90 / 10 27 0,5 2922 26 29,6 730 80 / 20 24 0,7 2703 17 21,1 770 70 / 30 20 0,9 2445 4 11 800
[0032] It is worth noting that the proportion of mechanically activated particles of ≈30% act as a filler-binder, and the remaining proportion of brown rot particles with a high lignin content mainly act as a filler, which is confirmed by the values of the physical and mechanical properties of the material, which is characterized by its relative fragility, but has high strength of interfiber bonds and dimensional stability, improved moisture-resistant properties.
[0033] This invention makes it possible to obtain a wood fiber board from wood affected by wood-destroying fungi, which helps to reduce energy costs in the production of wood boards with high physical and mechanical properties.
Claims
A method for producing a wood fiber board, which includes grinding wood into chips, followed by the production of a semi-finished wood fiber product, using waste chips, followed by hydrodynamic processing, to obtain wood pulp, casting a wood fiber carpet, cold pressing and hot pressing, characterized in that the wood of Siberian fir after its damage by bark beetle and wood-destroying fungi is used as the initial raw material, wherein the obtained semi-finished wood fiber product from chips is mixed with wood pulp obtained from waste chips, sifted to a fraction of 5 mm and below, serving as a binder in the following ratio, in wt.%: semi-finished wood fiber product - 70-90, wood pulp - 10-30.