Method for producing a composite material based on wood waste

Abstract

A method for producing a composite material based on wood waste, from particles of a lignocellulose substance obtained from softwood, characterized in that - the sawn timber, namely particles of a lignocellulose substance obtained from softwood, are planed with a four-sided planing machine, - the resulting shavings are transported to a storage silo via a compressed air system, - then the chips are conveyed from the silo to a sorting machine whose rollers have a rotational speed of 100-130, preferably 115 revolutions per minute, until a chip mixture is obtained, - whereupon the sorted shavings in a quantity of 20 m 3 / h to be transported to a horizontal mixer, - whereupon a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 35.3 to 41.2 parts water, 1.0 to 1.53 parts ammonium sulfate, 0.29 to 0.41 parts boric acid, preferably in a ratio of 37.2 : 1.2 : 0.35 and in an amount of 25 to 35, preferably 32 liters of the mixture per 1 cubic meter of chips is added, - then repeat the whole process at a shaft speed of 2-5, preferably 3 min / m 3 until the mixture is homogenized, - and then the mixture is dried at a temperature of 45-60, preferably 55°C in a tunnel dryer until a composite material is obtained, consisting of 97-98%, preferably 98% wood chips; 0.8-1.5%, preferably 1.0% ammonium sulfate (NH4)2SO4; 0.2-0.5%, preferably 0.5% boric acid H3BO3; and having a moisture content of 12-15%, preferably 12.5%.

Description

[0001] The invention relates to a method for producing a composite material based on wood waste that meets the requirements for fire resistance and resistance to biocorrosion and that is used as insulating material for building walls and partition walls.

[0002] Modern and eco-friendly thermal insulation is designed to be environmentally friendly and improve indoor air quality. Increasing emphasis is being placed on insulation materials of organic origin, made from renewable resources such as wood chips, wood fibers, wood wool, cork, flax, hemp, sheep's wool, cellulose, reeds, and straw. These materials meet almost 100% of the requirements for sustainable development.The main advantages of thermal insulation made from natural raw materials include: conservation of natural resources; environmentally friendly production; a balanced, almost closed CO2 balance (during their growth, the plants absorb such a large amount of CO2 from the atmosphere that it is released when the waste from these materials is disposed of); energy savings (little energy is consumed in the production of this type of insulation); no pollutant emissions into the atmosphere during use, disposal, and processing of the material; easy waste disposal; and short transport routes (regional materials). These insulations are characterized by excellent thermal and moisture properties: they are vapor-permeable, have good thermal capacity, and can transport moisture within the material without reducing its thermal performance, as evidenced by their high sorption capacity.Such solutions ensure a stable microclimate indoors, both in winter and summer. To give these materials additional properties, flame retardants, fire-retardant agents, and other substances that increase their resistance to biocorrosion can be added. During appropriate technological processes, the aforementioned raw materials are prepared accordingly, including drying, grinding, modification, pressing, or thickening. Despite the various additives and modification processes, such insulating materials remain harmless to human health and pose no risk to the surrounding environment. Their excellent acoustic insulation is another significant advantage.

[0003] Patent application WO 00 / 21 743A1 discloses reinforced composite materials containing cellulose fibers dispersed in a matrix, wherein the matrix contains a polymerized material, preferably a thermoplastic with a melting point above 180°C, and wherein the purity of the cellulose fibers with respect to alpha-cellulose is above 80 wt.%. The invention also includes methods for the production and application of composite materials.

[0004] Patent specification PL 187 621 B1 describes a method for manufacturing noise-reducing panels made of wood-concrete – in particular for freestanding walls protecting against traffic noise, for panels whose outer surface has parallel grooves with symmetrically outwardly diverging side walls, in which a mass containing a cellulose filler mineralized with calcium chloride, as well as cement paste, is prepared, the panel is then formed using a vibratory-pressure process, the cellulose filler being softwood mechanically crushed into rods whose length is 0.4 to 0.9 times the dimension of the shortest side of the polygonal line marking the outline of the cross-section of the grooved panel, except for the side forming the bottom of the groove, the cross-section of the rods being 2 to 6 mm and their moisture content not exceeding 20%, wherein the mass from which the panel is formed,The following components, in weight proportions, are included: rod-shaped cellulose filler in an amount of 100 to 140, Portland cement 180 to 220, calcium chloride CaCl2 5 to 8, plasticizer 0.5 to 1.5 and water in an amount of 80 to 120 parts by weight.

[0005] Patent specification PL 174 863 B1 discloses a method for preserving composite materials based on wood, wood-based materials and wood-like materials, which consists of defining points for the insertion of elements on the surface of an object to be treated, in particular a corroded object, at an angle of 0 to 60° to the horizontal plane, through which injection material is injected under pressure, most preferably in the form of two-component epoxy resin, after which, after it has completely solidified, the outer surfaces of the resulting composite material are subjected to an impregnating-penetrating process, wherein the mutual distance between the individual points is smaller than the smaller side or the radius of the object to be treated, and the distance of the outermost points from the edge of the object is less than half the distance between them.

[0006] A method for manufacturing a wood-based building panel according to patent specification PL / EP 3802034 T3 comprises the following phases: providing wood chips; reducing wood chips to wood fibers in a refiner for 3 to 20 minutes under a pressure of 4 to 16 bar; bonding wood fibers with phenolic resin, wherein the weight ratio of the solid resin components to the wood fibers is 10 to 50 parts resin to 100 / 35 parts wood fibers; pre-compression of fibers in a press at a pressing temperature of less than 110°C, resulting in the formation of a chemically reactive fiberboard; and pressing pre-compressed fiber panels into boards at a temperature between 130 and 180°C.

[0007] Patent specification PL 230 478 B1 discloses a method for producing a wood-based composite material, consisting of immersing pre-processed chips, reduced to a size of 4-40 mm, in a 5-50% protein solution for at least 2 hours. The chips are then strained, and expanding graphite is added to the wet, protein-soaked chips in a weight ratio of 9:1. The chips are then thoroughly mixed with the graphite until good adhesion is achieved, resulting in a uniform coating of the chip surface. The mixture is then stored for 48 hours for pre-drying, after which the dried chips are subjected to kiln drying at a temperature of at least 60°C. The composite material produced in this way is then processed.

[0008] The components of the composite material used in the invention fulfill the following functions: Wood chips – particles of a lignocellulose substance obtained from softwood, which are produced as a by-product during the mechanical processing of softwood intended for other assortments – form an insulating material and thus a basis, substrate for the other components of the composite material.

[0009] Additives that offer protection against biocorrosion are active substances that, as potential active components, protect the lignocellulosic particles from possible biocorrosion. These can be the following chemical compounds in pure form or in the form of ready-made, commercially available preparations: boric acid, propanoic acid, ethyl butyl acid, tannic acid, and derivatives of isothiazolone. Boric acid is a well-known, biologically active substance commonly found in wood preservatives, as discussed in the following publication: Mazela B. (2008): “Perspectives on increasing wood durability with regard to environmental protection requirements” (original Polish: “Perspektywy zwiększania trwałości drewna w aspekcie wymogów ochrony środowiska”), Poznań University of Natural Sciences Press; Scientific papers 397. Boric acid (also called orthoboric acid, trioxoboric acid) is an inorganic chemical compound, a weak acid with the formula H3BO3.In nature, it occurs as the mineral sassolin. The salts of boric acid are called borates (orthoborates). Boric acid is used as a fertilizer, disinfectant, and insecticide. It is also used as a preservative. On the list of E numbers for food additives approved in the European Union, it is designated with the symbol (E-284). The optimal concentration in aqueous solution is 5%. The effectiveness of boron compounds in wood preservation has been known for many years from the following publications: Lutomski K., Neyman SS (1976): Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration. IRG / WP 262; Lloyd JD, Dickinson DJ, Murhy RJ (1990): The probable mechanism of action of boric acid and borates as wood preservatives. IRG / WP 1450; Troya DE MT, Navarette AM(1991): Laboratory screening to determine the preventive effectiveness against blue stain fungi and molds. IRG / WP 3677, Drysdale JA (1994): Boron treatments for the preservation of wood - A review of efficacy data for fungi and termites. IRG / WP 94-30037, Kartal SN, Shinoda K, Imamura Y (2005): Laboratory evaluation of boron-containing didecyl dimethyl ammonium tetrafluoroborate (DBF) for inhibition of mold and stain fungi. Wood a. Raw materials and workpieces 63:73-77, Kartal SN, Hwang WJ; Patent PL 230 478 B1; Shinoda K., Imamura Y. (2006): Laboratory evaluation of boron-containing quaternary ammonia compound, didecyl dimethyl ammonium tetrafluoroborate (DBF) for control of decay and termite attack and fungal staining of wood. Holz a. Roh- u. Werkst. 64: 62-67. These are among the few active ingredients with high efficacy and simultaneously low toxicity to higher organisms (Kartal et al. 2005, 2006).According to the law on biocidal preparations, there are currently no restrictions on the use of boron compounds in wood preservation, which is why they play the main role in practice.

[0010] Ammonium sulfate consists of ammonium sulfate (VI), ammonium nitrate (V), and water. It is primarily used in agriculture, industry, and pharmaceuticals. Ammonium sulfate is a non-flammable product and is also used as a component of fire extinguishers. According to the safety data sheet, ammonium sulfate is a non-flammable product—it has no flammable properties and does not release readily flammable gases upon contact with water. Furthermore, the information regarding the auto-ignition temperature indicates that the substance is stable and that self-heating of the substance up to 400 degrees Celsius is impossible.

[0011] The solution according to the present invention is a method for producing a composite material based on wood waste, particles of a lignocellulose material derived from softwood, characterized in that the sawn wood, namely particles of a lignocellulose material derived from softwood, is planed with a four-sided planer, and the resulting chips are conveyed via a compressed air system to a storage silo, whereupon the chips are conveyed from the silo to a sorting machine, the rollers of which have a rotational speed of 100-130, preferably 115 revolutions per minute, until a chip mixture is obtained, whereupon the sorted chips are conveyed in a quantity of 20 m³ 3 / h to a horizontal mixer, wherein a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 35.3 to 41.2 parts water, 1.0 to 1.53 parts ammonium sulfate, 0.29 to 0.41 parts boric acid, preferably in a ratio of 37.2 : 1.2 : 0.35 and in an amount of 25 to 35, preferably 32 liters of the mixture per 1 cubic meter of chips, then the whole is transported at a shaft speed of 2-5, preferably 3 min / m 3 The mixture is mixed until it is homogeneous, whereupon the mixture is dried at a temperature of 45-60, preferably 55°C in a tunnel dryer until a composite material is obtained, consisting of 97-98, preferably 98% wood chips; 0.8-1.5%, preferably 1.0% ammonium sulfate (NH4)2SO4; 0.2-0.5%, preferably 0.5% boric acid H3BO3; and having a moisture content of 12-15, preferably 12.5%.

[0012] The following technical advantages and benefits were achieved through the application of the solution according to the invention: - The composite material represents an environmentally friendly material, - Protection of natural resources, - Environmental friendliness in manufacturing, - Balanced, almost closed CO2 balance (during their growth, the plants absorb such an amount of CO2 from the atmosphere that it is released when these materials are disposed of as waste), - Energy savings, - Absence of pollutant emissions into the atmosphere during use, waste disposal and processing of the material, as well as easy disposal of waste, - Short transport routes - regional materials, - The composite material has very good thermal and moisture properties and offers good acoustic protection, - The composite material is vapor-permeable, has good heat capacity and can transport moisture within the material without reducing its thermal performance. - The possibility of achieving a stable microclimate inside the building elements of building walls.

[0013] The invention is illustrated by the following examples: Example 1

[0014] A process for producing a composite material based on softwood waste is characterized by the following: the sawn timber is planed with a four-sided planer, and the resulting chips are conveyed via a compressed air system to a storage silo. From there, the chips are transported to a sorting machine whose rollers rotate at 100 revolutions per minute until a chip mixture is obtained. The sorted chips are then processed in quantities of 20 m³. 3 / h transported to a horizontal mixer, then a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 35.3 parts water, 1.0 parts ammonium sulfate, 0.29 parts boric acid, and in a quantity of 25 liters of the mixture per 1 cubic meter of chips is added, the whole thing being rotated at a shaft speed of 2 min / m 3 The mixture is mixed until it is homogenized, and the mixture is dried at a temperature of 45°C in a tunnel dryer until a composite material is obtained consisting of 99% wood chips; 0.8% ammonium sulfate (NH4)2SO4; 0.2% boric acid H3BO3; and having a moisture content of about 12%. Example 2

[0015] A process for producing a composite material based on softwood waste is characterized in that the sawn timber is planed with a four-sided planer and the resulting chips are conveyed via a compressed air system to a storage silo, then the chips are conveyed from the silo to a sorting machine whose rollers have a rotational speed of 130 revolutions per minute, until a chip mixture is obtained, wherein the sorted chips are in a quantity of 20 m 3 / h to a horizontal mixer, and a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 41.2 parts water, 1.53 parts ammonium sulfate, 0.41 parts boric acid, and in a quantity of 35 liters of the mixture per 1 cubic meter of chips is added, whereupon the whole is rotated at a shaft speed of 5 min / m 3The mixture is blended until it is homogeneous. The resulting mixture is dried at a temperature of 60°C in a tunnel dryer until a composite material is obtained, consisting of 97% wood chips; 2% ammonium sulfate (NH4)2SO4; 1% boric acid H3BO3; and having a moisture content of 15%. Example 3

[0016] A process for producing a composite material based on softwood waste is characterized by the following: the sawn timber is planed with a four-sided planer, and the resulting chips are conveyed via a compressed air system to a storage silo. From there, the chips are transported to a sorting machine whose rollers rotate at 115 revolutions per minute until a chip mixture is obtained. The sorted chips are then delivered in quantities of 20 m³. 3 / h to a horizontal mixer, to which a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 37.2 parts water, 1.2 parts ammonium sulfate, 0.35 parts boric acid, and in a quantity of 32 liters of the mixture per 1 cubic meter of chips, is added, then the whole is mixed at a shaft speed of 3 min / m3 until the mixture is homogenized, whereupon the mixture is dried at a temperature of 55°C in a tunnel dryer until a composite material is obtained which consists of 98% wood chips; 1.5% ammonium sulfate (NH4)2SO4; 0.5% boric acid H3BO3; and which has a moisture content of about 12.5%.

Claims

[1] Method for producing a composite material based on wood waste, from particles of a lignocellulose derived from softwood, characterized by , that - the sawn timber, namely particles of a lignocellulose substance obtained from softwood, are planed with a four-sided planing machine, - the resulting shavings are transported to a storage silo via a compressed air system, - then the chips are conveyed from the silo to a sorting machine whose rollers have a rotational speed of 100-130, preferably 115 revolutions per minute, until a chip mixture is obtained, - whereupon the sorted shavings in a quantity of 20 m 3 / h to be transported to a horizontal mixer, - whereupon a working fluid in the form of a mixture consisting of water, ammonium sulfate and boric acid in a ratio of 35.3 to 41.2 parts water, 1.0 to 1.53 parts ammonium sulfate, 0.29 to 0.41 parts boric acid, preferably in a ratio of 37.2 : 1.2 : 0.35 and in an amount of 25 to 35, preferably 32 liters of the mixture per 1 cubic meter of chips is added, - then repeat the whole process at a shaft speed of 2-5, preferably 3 min / m 3 until the mixture is homogenized, - and then the mixture is dried at a temperature of 45-60, preferably 55°C in a tunnel dryer until a composite material is obtained, consisting of 97-98%, preferably 98% wood chips; 0.8-1.5%, preferably 1.0% ammonium sulfate (NH4)2SO4; 0.2-0.5%, preferably 0.5% boric acid H3BO3; and having a moisture content of 12-15%, preferably 12.5%.