RU206509U1 - CONSTRUCTION WOOD CHIP PLATE WATERPROOF "WATERPROOF WOOD-BOARD" - Google Patents

Abstract

The utility model relates to the structure of moisture-resistant chipboards for construction purposes, obtained by hot flat pressing of wood particles mixed with a binder. A technical problem is the creation of a construction chipboard that has a low energy consumption due to a decrease in the temperature of its pressing and provides the specified performance indicators, in particular, moisture resistance. The technical result consists in increasing the moisture resistance and durability of the building board due to the formation of its multilayer structure with physical properties of different thickness, providing different density of layers and, as a result, their thermal conductivity, and a decrease in temperature and heating duration during pressing prevents thermal decomposition of the binder. This moisture resistant construction chipboard is a layered structure formed by the outer and inner layers of coniferous wood and aspen in equal proportions, of which the outer layer is formed by plane chips oriented in the plane of the board, the linear size of which exceeds the corresponding linear size of the resinous particles of the needle-shaped inner layer , the structure of which is chips crushed in a gear crusher. The inner layer also contains resinous particles of the outer layer, which are evenly distributed in it, introduced in the form of crushed waste of board trimming according to its specified dimensions, and the chips are treated with BASF Dispers Green 8711 colorant and uniformly resinified with urea-melamine-formaldehyde resin with a hardener in the form of ammonium sulfate, and the board is treated with paraffin wax emulsion, as a result of which the slab with a density of 780-820 kg / m3 has a swelling in thickness in 24 hours - 13%, swelling in thickness in 48 hours - 18%, swelling in thickness in 72 hours - 24.5%, with full integrity the structure and shape of the slab. 2 c.p. f-ly, 2 pr.

Description

The technical solution relates to the structure of moisture-resistant chipboards for construction purposes, obtained by hot flat pressing of wood particles mixed with a binder.

Known is a layered moisture-resistant panel for construction purposes, made of oriented in layers of crushed wood materials, pressed at a temperature of about 205 ° C, the inner layer of which is impregnated with isocyanate resin, and the outer layer is impregnated with phenol-formaldehyde, and under these conditions the panel has a density of 624.72 kg / m ³ , water resistance is also achieved by the introduction of paraffin (RU No. 2380501, 27.01.2010).

The closest known is a wood board obtained by preparing pieces of wood, applying a carbohydrate binder composition to pieces of wood, molding the resulting pieces of wood to form a leaf, heating and pressing the resulting sheet to obtain a hardened wood board and post-curing the wood board, and the wood board is a wood board. particle board and pieces of wood are wood particles, and post-curing is carried out at a temperature in the range from 75 ° C to 280 ° C (RU No. 2627644, 08/09/2017).

Attempts to make urea-formaldehyde chipboards with reduced swelling when exposed to moisture, for example by using a larger amount of binder, have shown that the use of a significantly larger amount of binder negatively affects the overall properties of the chipboard, as well as economic efficiency, and cured UF binders remain hygroscopic. In addition, to reduce the swelling of UF / MUF chipboards, it has been proposed to expose the finished product to heat, as a result of which the chipboard usually becomes less hygroscopic and reduces stress due to hot pressing, but the active effect of heat also leads to degradation of the binders used for curing. which negatively affects the structural integrity of the product. At the same time, lowering the heating temperature requires a longer heating for the process to proceed completely, which leads to the decomposition of the binders.

A technical problem is the creation of a construction chipboard that has a low energy consumption due to a decrease in the temperature of its pressing and provides the specified performance indicators, in particular, moisture resistance.

The technical result consists in increasing the moisture resistance and durability of the building board due to the formation of its multilayer structure with physical properties of different thickness, providing different density of layers and, as a result, their thermal conductivity, while reducing the temperature and duration of heating during pressing, which prevents thermal decomposition of the binder.

The specified technical result is achieved by the fact that the moisture resistant construction chipboard has a layered structure formed by the outer and inner layers of coniferous wood and aspen in equal proportions, and the outer layer is formed by plane chips oriented in the plane of the board, the linear size of which exceeds the corresponding linear size of the resinified particles needle-shaped inner layer, the structure of which is shavings crushed in a gear crusher, while the inner layer also contains resinous particles of the outer layer that are evenly distributed in it, introduced in the form of crushed board trimming waste according to its specified dimensions, and the shavings are treated with a colorant BASF Dispers Green 8711 and uniformly resinified with urea-melamine-formaldehyde resin with a hardener in the form of ammonium sulfate, and the board is treated with paraffin emulsion, and the board with a density of 780-820 kg / m ³ has a swelling in thickness in 24 hours - 13%, swelling swelling in thickness in 48 hours - 18%, swelling in thickness in 72 hours - 24.5%, with full preservation of the integrity of the structure and shape of the slab. For this, 1 m ^{3 of a} moisture-resistant P3 type construction chipboard with the specified properties is formed from 680 kg of the mentioned wood raw material in terms of abs. dry wood, urea-melamine-formaldehyde resin - 71.6 kg in terms of abs. dry resin, paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62% - 6.0 kg in terms of absolute dry. paraffin, ammonium sulfate - 0.7 kg in terms of abs. dry component and colorant BASF Dispers Green 8711 - 0.3 kg. Or 1 m ^{3 of a} moisture resistant P5 type construction chipboard with the specified properties is formed from 707 kg of abs. dry the specified wood raw material, 74.8 kg in terms of abs. dry urea-melamine-formaldehyde resin, paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62%, paraffin 6.0 kg in terms of abs. dry., ammonium sulfate 0.7 kg in terms of abs. dry and colorant BASF Dispers Green 8711 - 0.3 kg.

The specified technical result is achieved by all the features of the independent claim, as essential, due to the fact that the plate is made of a layered structure with an increase in its density in the central layer due to the shape of the chips, which is different from the shape of the peripheral layers, in the central layer, the board returned after cutting is used and resinous shavings, previously crushed in a gear crusher to the required fraction in this layer. The uniform resinification of the layer shavings makes it possible to ensure their isolation from the environment, including moisture insulation, and the use of these components allows to reduce the temperature of hot pressing of the board, practically to 190 ° C, which excludes the decomposition of the binder, which can lead to the destruction of the shell covering the shavings. Thus, with an increased density of the slab of 780-820 kg / m ^3, its swelling in thickness in 24 hours is 13%, swelling in thickness in 48 hours is 18%, swelling in thickness in 72 hours is 24.5%, which provides the indicated above is the technical result and meets the set operational requirements.

For an example of implementation, a description of the full cycle of manufacturing a moisture-resistant chipboard is given.

Non-commercial coniferous and deciduous wood (spruce, pine and aspen) is used as a raw material. Raw materials are delivered to the plant by road and rail. The adhesive material is low-toxic urea-melamine-formaldehyde resin. The unloading of wood raw materials from road and rail transport is mechanized. Storage of raw materials is carried out in a stacking way in a warehouse. Wood raw materials from the raw material warehouse are transferred to two processing lines: one based on a UTC-1000-2N chipper from Kikai; the second - a shaving machine with a knife shaft mod. U112 / 2-80 from Hombak. On a chipper, raw materials are processed into technological chips, on a shaving machine - into shavings. Chips are sorted on a vibrating screen into two fractions: conditioned and screened. Screening of wood chips is used as fuel in the waste heat recovery boiler house. To create an interoperational stock, conditioned chips are accumulated and stored in a closed mechanized warehouse with a volume of 7000 m ³ . Conditioned chips on a shaving machine mod. PZKR 12-375 from Pallman is crushed into needles. From the shaving machines by the system of mechanical transport devices the shavings are directed into two vertical hoppers with a volume of 235 m ³ each. The operation of the equipment for supplying wood raw materials to production, crushing it, separating conditioned chips from the products of crushing and making shavings is carried out automatically within the framework of a unified automatic control system for the technological process (SAUTP). The shavings discharged from the storage bins by screw conveyors in the required ratio enter the drying unit. Drying of shavings to a moisture content of 1.5 ± 0.3% is carried out in a drying unit by means of a combined convective-contact method of heat transfer to the material to be dried. The drying agent is the flue gas obtained in the heat generator (furnace) when grinding dust and liquid fuel are burned in it. Separation of the dried chips from the spent drying agent is carried out in cyclone separators, from which it is collected in a single stream and sent to a vertical hopper with a volume of 117 m ³ . The spent drying agent undergoes additional cleaning from the dust-like fraction of the shavings in a special filter. The drying unit is equipped with an automatic "Cre-Con" spark extinguishing system. From the vertical hopper, the dry chips by means of a system of mechanical conveyors are sent for sorting in a predetermined ratio. Dry chips intended for the outer layers are crushed in a gear crusher mod. PSKM 15 - 720, complete with vibrating feeder, drum magnetic and air-gravity separators. The shavings crushed in a gear crusher by the pneumatic transport system and reversible screw conveyors are fed to the sorting mod. ARSM 331 in order to highlight its conditioned part for the formation of outer layers. Conditioned shavings for the outer layers are fed by a pneumatic conveying system into a vertical hopper with a volume of 163 m ³ . Wood particles not passed through the sorting sieve mod. ARSM 331 are returned for regrinding in a gear crusher mod. PSKM 15 - 720. Dry chips supplied to the process flow of the inner layer are screened in two stages - mechanical screening model ARSM 33-10 and pneumatic screening. Sorting of shavings on mechanical sorting mod. ARSM 33-10 is designed to separate small fractions from their entire mass, which are selected by the pneumatic conveying system and sent to the process flow of the outer layers, where they are mixed with the flow of crushed shavings by a crusher mod. PSKM 15-720. Chips that have not passed through the sorting sieve mod. ARSM 33-10, goes to pneumatic sorting for separation of coarse fraction from their mass and supply of the conditioned part to a vertical hopper for interoperational storage of shavings for the inner layer. The large fractions of shavings separated in the pneumatic sorting through the sluice gates enter the pneumatic transport system and are transferred to the flow of the outer layers, where they are mixed with the flow of small wood particles taken from the sorting modes. ARSM 33-10 and shredded wood particles coming from the gear crusher mod. PSKM 15 - 720. Urea-melamine-formaldehyde resin is stored in closed containers, protected from sunlight and atmospheric precipitation. Resin from the warehouse to the binders preparation section is piped into two supply tanks with a volume of 25 m ³ each, and the chemicals in containers are delivered by road. Preparation of working solution flows resin for the outer and inner layers is carried out automatically by the commodity resin mixed with water in a weight capacity with working volume of 05 m ³ Cooked Resin solutions of predetermined concentrations by gravity overflow to the appropriate feed tank 1.0 m ³ volume mounted on the electronic weighing device. Aqueous solutions of the hardener are prepared in two mixing vessels intended for the flows of the outer and inner layers, respectively. The prepared solutions of hardeners of each independent flow are pumped by pumps into corresponding storage tanks with a volume of 1.35 m ³ , equipped with fill level sensors and agitators. As required, in automatic mode, solutions of hardeners are pumped from storage tanks into interoperable storage tanks with a volume of 025 m ³ , equipped with three-level filling sensors. From these containers, the solutions are fed by gravity into the supply containers, each of which is installed on an electronic weighing device. Mixing of solutions of hardeners and resin for the preparation of binders of different technological streams is carried out in appropriate tubular mixers. The components of the binder are supplied to them by pumping units with variable capacity. Mixing of wood particles with a binder is carried out in high-speed mixers mod. К-ТТР 350 for the outer layers and К-ТТР 500 for the inner layer with cooling of the mixing shaft and the mixing chamber housing with chilled water. The dosing of dry wood particles into the mixers by weight is carried out with the corresponding belt scales mod. DTL. For operational control of the moisture content of wood particles, each belt weigher is equipped with a continuous infrared moisture meter mod. 4C-N1 / 475. Dosing of the binder into the mixer is carried out in a volumetric manner by pumping units for supplying its components with control of the supplied amount by an electronic weighing device of the supply containers of these components. Mixed with a binder (resinous) shavings are transferred from the mixer to the section for forming the particle carpet by separate screw conveyors with cooling. The formation of a chip carpet is carried out by a complex consisting of three forming machines: two extreme for the formation of the outer layers of the carpet; medium - for the inner layer. Forming machines operate on the principle of continuous dosing of the mass of resinous shavings with its subsequent size division in the air flow of the fractionation chamber of the outer layers and mechanical dispersion during the formation of the inner layer. Screw conveyors transfer the tar chips to metering hoppers located above each forming machine. The dosing hoppers compensate for the change in the mass of the resin shavings flow over time, average them in terms of humidity, resinification quality and fractional composition, providing the most accurate dosing. The bins are equipped with filling sensors that provide a corresponding indication on the control panel. Forming machines designed for filling the outer layers have air flows with opposite directions to each other. To prevent the ingress of dust-resin lumps and coarse shavings on the surface of the carpet, in each of the fractionation chambers, three separate vibrating grids are sequentially installed across the air flow. The inner layer forming machine is equipped with a filling device consisting of a system of adjustable dampers, sliders and valves, rotating toothed rollers and spoke drums. This filling device divides into two equal streams, coming from the dosing hopper, the addition of resinous shavings and evenly distributes them by mechanical dispersion on the surface of the carpet being formed. Particle carpet is formed on mesh pallets, moved by a forming conveyor and forming an endless belt on it due to their overlapping arrangement. Forming conveyor speed is infinitely variable. The weight of the particle carpet together with the mesh tray is determined by an electronic weighing device. The empty weight of the carpet is defined as the difference between the value set by the weighing device and the mass of the pallet, the value of which came from the register reading device. The measurement results are in the form of a mass of 1 linear meter. m of the length of the formed carpet and the percentage deviation of this value from the set value are transmitted to the control panel and recorded on the computer display. The operation of the equipment for the preparation of the working solution of resin, hardener and binder, dosing of wood particles and binder, mixing them and forming a particle carpet is also carried out in an automatic mode by one command and control unit based on a SIEMENS processor within the framework of a unified automatic process control system (SAUTP). To compact the particle carpet formed on mesh pallets and create a smooth surface, it is rolled in a continuous way using a rotating drum installed above the forming conveyor. The clamping force is regulated by the value of the counterweight installed on the drum suspension arm. The tape of the continuously formed carpet is cut to length into briquettes by a dividing device. The dimensions of the briquette are 12890 × 2490 mm with a tolerance of ± 10 mm. Resinous wood particles formed during carpet cutting are removed by a pneumatic conveying system and sent to the dosing hopper of the inner layer forming machine. Pallets with substandard packages identified by the weighing device must be removed at the end of the forming conveyor by being pulled under it with a chain conveyor. In this case, the resinous wood particles, forming a substandard package, are poured into the receiving pocket, and the pallet itself is transferred to the beginning of the forming conveyor by its lower branch. From the receiving pocket, the poured material is fed by the pneumatic transport system to the hopper for collecting production waste for subsequent return to the technological process together with raw shavings. Exhaust air enters the filter unit, from where it is released from wood dust into the atmosphere. Pallets with conditioned packages are transferred from the forming conveyor to the accelerating conveyor, which are fed alternately to one or the other floor of a two-storey loading rack. After filling both floors of the loading stack, mesh pallets with chip packages located on them are intercepted by the loading and unloading press conveyor and transferred to the press while simultaneously removing from the latter two previous pallets with ready-made chipboards located on its heating plates. Pressing of chip packages is carried out in a double-deck hydraulic press of periodic action mod. HPOG / 2-11000 / 35 Sp with fixed lower table and movable upper beam. The press is equipped with a device for simultaneous clamping of plates. The press plates are heated by a high-temperature organic heat carrier. The temperature of the heating plates of the press is selected in the range of 190-210 ° C and is automatically maintained. Chipboard pressing is carried out with a stepwise release of pressure after reaching the thickness of the pressed package set by the distance bars. Removal of gases and vapors released during pressing is ensured by forced ventilation of the press cover. The process of pressing the chipboard and the operation of the pressing equipment is carried out in an automatic mode by one command and control unit based on the SIEMENS processor within the framework of a single SAUTP. The unloading of two finished slabs from the press on mesh pallets and their placement in a two-storey unloading stack, combined in time with the loading of the press of particle packs to be pressed, is carried out by an unloading device. From the unloading stacker, mesh pallets with ready-made slabs alternately go to the device for separating them from each other. The mesh pallets freed from the finished plates are transferred by the system of return conveyors to the forming conveyor. The plates separated from the mesh pallets are fed into a continuous-type fan cooler, in which they are cooled to a temperature of no more than 50 ° C. Gaseous air from under the cover of the fan cooler is removed by forced ventilation. The cooled plate is removed from the fan cooler onto a roller conveyor, which is fed for longitudinal cutting on a longitudinal edger. The trimmed slab goes to the roller conveyor of the shear-shear for simultaneous cross-cutting into seven parts of 2440 ± 5 by 1830 ± 5 mm. Circular saws with carbide blades are used as cutting tools. Waste from the format cutting of the slab is crushed by crushing sectors with eight teeth each, set at an angle to the plane of the crusher disk. Sawdust, as well as crushed waste, is collected by a pneumatic transport system and sent to the waste collection bin for subsequent return to the technological process along with raw shavings. The exhaust air enters the filter, from where it is released from wood dust into the atmosphere. After sawing, the slabs are transferred one by one to the stacker table, where a stack is formed from them, which is fed to the floor roller conveyor. From the floor roller conveyor, the stack of plates is transferred to a mobile cart, which moves it to an intermediate storage warehouse, where they are kept for 48 hours in order to equalize the moisture content across the thickness of the plates and relieve internal stresses. To eliminate thickness differences and individual manufacturing defects on the surface and ensure the required roughness, the plates are polished evenly on both sides.

Grinding of chipboards and their subsequent sorting is carried out on an automated production line equipped with wide-belt grinding machines of "Steinemann" company. Grinding of slabs is carried out in two stages and includes calibration and finishing grinding. As an abrasive grinding tool, endless corundum or silicon abrasive belts on a combined basis are used. The grinding dust of the aspiration system is sent to the storage bin for further feeding for combustion in the furnace of the drying unit. Sorting of plates is carried out in accordance with the requirements of GOST 10632. Plates are stacked by brands and grades. The grinding line works in automatic mode. Chipboard packages are stored in stacks up to 4.5 m high. The stacks are formed by forklift trucks. In order to exclude emissions of wood dust into the atmosphere, the entire pneumatic transport has two stages of cleaning. Non-business waste from production is collected and burned in a utilization boiler house.

Examples of implementation:

1. For the manufacture of a moisture-resistant construction chipboard at the rate of 1 m ³ of a 10 mm type P3 slab were taken:

wood raw material according to GOST 3243-88 - 680 kg abs. dry wood;

urea-melamine-formaldehyde resin - 71.6 kg abs. dry resin;

paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62% - 6.0 kg abs. dry paraffin;

ammonium sulfate in accordance with GOST 9097-82 - 0.7 kg abs. dry .;

colorant BASF Dispers Green 8711 (manufacturer Shanghai, King, Chemicals, Co., Ltd. State registration certificate: RU.77.99.32.008.E.000258.01.17) - 0.3 kg;

2. For the manufacture of a moisture-resistant construction chipboard at the rate of 1 m ³ of a 10 mm type P5 slab, the following were taken:

wood raw material according to GOST 3243-88 - 707 kg abs. dry wood;

urea-melamine-formaldehyde resin - 74.8 kg abs. dry resin;

paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62% - 6.0 kg abs. dry paraffin;

ammonium sulfate in accordance with GOST 9097-82 - 0.7 kg abs. dry .;

colorant BASF Dispers Green 8711 (manufacturer Shanghai, King, Chemicals, Co., Ltd. State registration certificate: RU.77.99.32.008.E.000258.01.17) - 0.3 kg

In this case, urea-melamine-formaldehyde resin can be used as a resin, for example, KF-MT-15 (TU 6-06-12-88), KFZhm (GOST 14231-88), KF-HT-P (TU 2223-001-51119346- 2003) or another.

The specimens tested were prepared as described above.

The tests were carried out in accordance with the requirements:

GOST 10634-88 Chipboards. Methods for determining physical properties.

GOST 10635-88 Chipboards. Method for determining ultimate strength and flexural modulus.

GOST 10636-90 Chipboards. Method for determining the ultimate tensile strength perpendicular to the plate face.

GOST 15612-85 Products from wood and wood materials, methods for determining the parameters of surface roughness.

GOST 15846-2002 Products sent to the Far North and hard-to-reach areas. Packaging, labeling, transportation and storage.

GOST 18321-73 Statistical quality control. Methods for random sampling of piece products.

GOST 23234-78 Chipboards. Method for determining the resistivity at normal tear off of the outer layer.

GOST 24053-80 Chipboards. Method for determining warping.

GOST 27678-88 Particle boards and plywood. Perforating method for determining formaldehyde.

GOST 27680-88 Chipboards and fibreboards. Dimension and shape control methods.

EN 312: 2003 (E). Chipboards. Technical conditions.

EN 321. Wood-based panels - Determination of the water resistance of wood-based panels when tested under cyclic loading conditions.

As a result of the tests carried out, it was found that:

the use in the production of shavings obtained from two technological streams, flat cut shavings from the line of the Hombak chip machine and needle shavings obtained after crushing chips in the Palman chip machines, allows for a denser filling of the inner layer of the board, respectively, a decrease in (practically ) the presence of voids and an increase in the density of the inner layer of the slab by 20-30 kg (as a rule, the density of the inner layer of the slab is on average 80 kg / m ³ lower than the density of the outer layers);

the content of a colorant in such a material of the plate in the specified amount (0.3 kg per 1 m ^{3 of the} plate) leads to partial clogging of open pores, which reduces the possibility of swelling of the plate;

the physical and mechanical indicators of the produced slab are much higher than the requirements of GOST 32399-2013, namely:

density 780 -820 kg / m ³ ,

bending strength - up to 20 MPa (according to GOST 32399-2013 not less than 14 MPa),

tensile strength perpendicular to the face - 0.48 MPa (according to GOST 32399-2013 not less than 0.45 MPa),

swelling in thickness in 24 hours - 13% (according to GOST 32399-2013 no more than 14%).

In addition, the results of the tests carried out on the produced slab for the swelling index (not according to GOST):

swelling in thickness in 48 hours - 18%, with full preservation of the integrity of the structure and shape of the slab,

swelling in thickness in 72 hours - 24.5%, with full preservation of the integrity of the structure and shape of the slab.

Claims (3)

1. Building chipboard moisture resistant, having a layered structure formed by the outer and inner layers of coniferous wood and aspen in equal proportions, and the outer layer is formed by plane chips oriented in the plane of the board, the linear size of which exceeds the corresponding linear size of the resinous particles of the needle-shaped inner layer , the structure of which is shavings crushed in a gear crusher, while the inner layer also contains resinous particles of the outer layer that are evenly distributed in it, introduced in the form of crushed waste of board trimming according to its specified dimensions, and the shavings are treated with a colorant BASF Dispers Green 8711 and are uniformly tarred urea-melamine-formaldehyde resin with a hardener in the form of ammonium sulfate, and the board is treated with paraffin emulsion, while the board has at a density of 780-820 kg / m ³ : swelling in thickness in 24 hours - 13%, swelling in thickness in 48 hours - 18%, swollen not in thickness in 72 hours - 24.5%, with full preservation of the integrity of the structure and shape of the slab. 2. The board according to claim 1, characterized in that 1 m ³ of the P3 type board is formed from 680 kg of said wood raw material in terms of abs. dry wood, urea-melamine-formaldehyde resin - 71.6 kg in terms of abs. dry resin, paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62% - 6.0 kg in terms of abs. dry paraffin, ammonium sulfate - 0.7 kg in terms of abs. dry component and colorant BASF Dispers Green 8711 - 0.3 kg. 3. The plate according to claim 1, characterized in that 1 m ³ of the P5 type plate is formed from 707 kg of abs. dry the specified wood raw material, 74.8 kg in terms of abs. dry urea-melamine-formaldehyde resin, paraffin emulsion Aquavax R 1188СС with a paraffin content of 58-62%, paraffin 6.0 kg in terms of abs. dry., ammonium sulfate 0.7 kg in terms of abs. dry component and colorant BASF Dispers Green 8711 - 0.3 kg.