EA015896B1 - Wood board production method - Google Patents

Abstract

The inventive method can be used in the woodwork and timber industry for producing sheet building materials, furniture components and similar thermo-compressed products with the reduce energy consumption. The inventive wood board production method consists in producing a wood pulp from the particles of a ground vegetable raw material, in forming a flat wood pulp layer and in compacting it at a temperature ranging from 58 to 120°C. Said invention makes it possible to preserve useful natural compounds in the composition of the boards and to achieve the sufficiently high physico-mechanical characteristics of the products.

Description

The proposed technical solution relates to the field of forestry and woodworking industry and can be used in the manufacture of sheet building materials, furniture parts, etc. pressed products with sufficiently high physical and mechanical characteristics and improved environmental properties, at a reduced temperature of thermal pressing.

Similar technical solutions are known. So, for example, in the patent KP No. 2073044 describes a method for producing wood boards, the essence of which is as follows:

take vegetable raw materials in the form of peat grass-moss group and wood waste;

crushed plant material to a particle size of not more than 3 mm;

particles of peat and wood are mixed in the ratio (wt.%): peat particles - 5-99; pine wood particles - 95-1;

receive wood pulp from particles of crushed plant material;

dried the resulting wood pulp to a moisture content of 9%;

form dried wood pulp in a flat layer;

heating a flat layer of wood pulp to a temperature of 170 ° C;

apply force to the heated flat layer of wood pulp, creating a pressure in the range of 3.0-8.5 MPa, on the entire plane of the layer, with the duration of the combined effect of temperature and pressure, at the rate of 1 min / 1 mm of the plate thickness;

get a compacted, heated flat layer of wood pulp;

cool the heated, compacted flat layer of wood pulp to a temperature of 40 ° C, without removing the applied force;

relieve force from a cooled, compacted flat layer of wood pulp;

get wood boards.

Common features of this analogue and the proposed method for producing wood boards are the following:

take vegetable raw materials;

crushed vegetable raw materials;

receive wood pulp from particles of crushed plant material;

dried the resulting wood pulp;

form dried wood pulp in a flat layer;

heating a flat layer of wood pulp;

apply force to a heated flat layer of wood pulp, creating pressure on the entire plane of the layer;

get a compacted, heated flat layer of wood pulp;

cool a heated, compacted flat layer of wood pulp without removing the applied force;

relieve force from a cooled, compacted flat layer of wood pulp;

get wood boards.

The technical result, which cannot be achieved by the analogue described above, consists in lowering the temperature of heating a flat layer of wood pulp upon receipt of wood boards with sufficiently high physical and mechanical characteristics.

The reason for the impossibility of achieving the above technical result for this analogue is the high density of the pulp components, which makes it impossible to isolate the necessary and sufficient amount of active natural compounds contained in the plant components and forming a binder for the production of wood boards at a reduced temperature of the pulp during thermal pressing.

A well-known analogue adopted for the prototype is an abstract of Kartashov N.P. Development and implementation of technology for producing ligno-carbohydrate wood plastics from crushed logging waste. ULTI, Sverdlovsk, 1968

This work describes a method for producing wood-based panels, which is as follows: take vegetable raw materials in the form of coniferous logging waste with a moisture content of 60-70% in the composition (wt.%): Needles - 15, bast bark - 25, wood - 60;

crushed plant material in the form of coniferous logging waste of the above composition and humidity to a particle size of not more than 5 mm;

receive wood pulp, consisting of particles of fibrous structure, crushed coniferous logging waste, in the composition (wt.%): particles of needles - 15, particles of bast bark - 25, particles of wood - 60;

dried the resulting wood pulp to a moisture content of 17-20%;

form dried wood pulp in a flat layer;

heating a flat layer of wood pulp to a temperature equal to 160 ° C;

apply force to a heated flat layer of wood pulp, creating a pressure in the range of 2.6-5.1 MPa, on the entire plane of the layer, with the duration of the combined effect of temperature and

- 1 015896 pressure, at the rate of 1 min / 1 mm plate thickness;

get a compacted, heated flat layer of wood pulp;

cool the heated, compacted flat layer of wood pulp to a temperature of 30 ° C, without removing the applied force;

relieve force from a cooled, compacted flat layer of wood pulp;

get wood boards.

Common features of the prototype and the proposed method for producing wood boards are the following:

take vegetable raw materials in the form of coniferous logging waste with a moisture content of 60-70%;

crushed plant material in the form of coniferous logging waste with a moisture content of 60-70%, to a particle size of not more than 5 mm;

get a wood pulp consisting of particles of fibrous structure, crushed coniferous logging waste;

dried the resulting wood pulp;

form dried wood pulp in a flat layer;

heating a flat layer of wood pulp;

apply force to a heated flat layer of wood pulp, creating a pressure in the range of 2.6-5.1 MPa, on the entire plane of the layer, with the duration of the combined effect of temperature and pressure at the rate of 1 min / 1 mm of the plate thickness;

get a heated, compacted flat layer of wood pulp;

cool the heated, compacted flat layer of wood pulp to a temperature of 30 ° C, without removing the applied force;

relieve force from a cooled, compacted flat layer of wood pulp;

get wood boards.

The technical result that cannot be achieved by the prototype is to reduce the heating temperature of a flat layer of wood pulp, upon receipt of wood boards with a sufficiently high physical and mechanical characteristics.

The reason for the inability to achieve the above technical result of the prototype is the high content of dense wood in the wood pulp in the form of particles of chopped branches and tops of conifers, which does not allow to isolate, at a reduced mass heating temperature, a sufficient amount of active natural compounds contained in plant components necessary for the formation of a binder upon receipt of wood boards.

Given the characteristics and analysis of known similar technical solutions, we can conclude that the task of obtaining wood boards from widespread plant materials, with the achievement of a sufficiently high physical and mechanical characteristics of products, with reduced energy consumption, is relevant today.

The technical result indicated above is achieved by the fact that the method of producing wood boards consists in taking plant material in the form of coniferous logging waste, chopping the plant material in the form of coniferous logging waste, producing wood pulp from particles of crushed coniferous logging waste, and drying the resulting wood pulp form the dried wood pulp with a flat layer, heat the flat wood pulp layer, apply a force to the heated flat wood pulp layer (creating pressure on it), obtain a flaxed, heated flat layer of wood pulp, cool the heated compacted flat layer of wood pulp (without removing the applied force), remove the force from the cooled, compacted flat layer of wood pulp and obtain wood boards, while taking plant material in the form of coniferous logging waste containing wood not more than 43 wt.%;

dried the resulting wood pulp to a moisture content of 18-40%;

heat a flat layer of wood pulp to a temperature of 58-120 ° C.

The choice of plant materials in the form of coniferous logging waste with a wood content of not more than 43 (wt.%); drying the wood pulp to a moisture content of 18–40% and heating a flat layer of wood pulp to a temperature of 58–120 ° С allow the pulp to be obtained in the process of grinding the selected plant material with a reduced content of dense wood particles, which contributes to a more intensive release of active natural compounds from the components of the mass at a reduced heating temperature and the formation of a sufficient amount of binder, in the process of subsequent thermal compaction of the wood pulp, to obtain wood boards with residually high physical-mechanical characteristics, to dry the pulp to a moisture content in the range 18-40%, which helps to optimize the processes of formation of the binder and a better distribution when termouplotnenii pulp;

form dried wood pulp in a flat layer;

- 20155896 heat it to a temperature in the range of 58-120 ° C, which allows to reduce energy consumption and to save most of the environmentally useful volatile compounds, such as volatile, flavonoids, bornyl acetate, etc., which are known to at high temperature heating evaporate and destruct;

make an effort and compact the heated flat layer of wood pulp, and after cooling it under pressure, in order to finally form, distribute and set the binder, up to 30 ° С, relieve pressure and obtain wood boards with sufficiently high physical and mechanical characteristics. In this, the achievement of the technical result indicated above is manifested.

It was experimentally established that the content in the wood pulp of particles with a density of coniferous wood of more than 43 wt.% Does not allow to isolate from the components a sufficient amount of active natural substances necessary for the formation of a binder and to obtain wood boards with sufficiently high physical and mechanical characteristics, at a heating temperature masses less than 120 ° C during its heat sealing;

moisture content of wood pulp less than 18% reduces its ductility, strength and moisture resistance of the plates obtained from it, and moisture content of the mass of more than 40% also leads to a decrease in the strength and moisture resistance of the plates;

heating the wood pulp to a temperature of less than 58 ° C significantly slows down the process of isolating the active substances and carrying out the reactions of formation of a binder from them during heat compaction of wood pulp, and heating the wood pulp to a temperature of more than 120 ° C increases energy consumption, while the useful substances contained in it evaporate and degrade volatile compounds.

The technical essence of the proposed method for producing wood boards is as follows:

take vegetable raw materials in the form of coniferous logging waste, with a wood content of not more than 43 wt.%;

crushed plant material in the form of coniferous logging waste;

receive wood pulp from particles of crushed coniferous logging waste; dried the resulting wood pulp to a moisture content of 18-40%;

form dried wood pulp in a flat layer;

heating a flat layer of wood pulp to a temperature in the range of 58-120 ° C;

apply force to a heated flat layer of wood pulp;

get a compacted, heated flat layer of wood pulp;

cool a heated, compacted flat layer of wood pulp without removing the applied force;

the force is removed from the cooled compacted flat layer of wood pulp and wood boards are obtained.

In practice, the method of producing wood boards is as follows:

take plant material in the form of coniferous logging waste with a natural moisture content of 60-70% in a composition excluding the dense wood content of more than 43 wt.%, for example, coniferous spruce branches (branches covered with needles growing on them) or its components (needles and / or bast bark );

crushed the selected plant material with a natural moisture content of 60-70% to a particle size of not more than 5 mm by known methods, for example in a hammer mill;

receive wood pulp from crushed plant material, consisting of particles of fibrous structure, with a content of wood particles of not more than 43 wt.%;

dried the resulting wood pulp to a moisture content of 18-40% by known methods, for example in a dryer;

form the dried wood pulp in a flat layer by one of the known methods;

heating a flat layer of wood pulp to a temperature of 58-120 ° C by known methods, for example between heated press plates;

apply force to a heated flat layer of wood pulp, creating a pressure of 2.65.1 MPa on it, with the duration of the combined effect of temperature and pressure, depending on the specified thickness and density of the resulting slab, optimally - over a period of time at the rate of 1 min / 1 mm the thickness of the product, by known methods, for example, using a press (while heating and applying a force that creates pressure on the layer is carried out simultaneously);

get a compacted heated flat layer of wood pulp;

cool the heated compacted flat layer of wood pulp, without removing the applied force, to 30 ° C by known methods, for example, by air flow;

the force is removed from the cooled compacted flat layer of wood pulp and wood boards are obtained.

To confirm the achievement of the above technical result and the physicomechanical characteristics of the plates, samples were made and tested according to GOST 10632-89.

Samples were obtained according to the proposed method at reduced temperatures

- 3 015896 heating, observing the relevant technical conditions and technological parameters of the prototype: pressure 2.6-5.1 MPa, duration of hot pressing 1 min / mm of the thickness of the product, cooling to 30 ° C under pressure.

Key indicators are presented in the table.

Samples T hail. FROM Physical and mechanical characteristics Density kg / m3 Bending Strength (MPa) Water absorption (% in 24 hours) Swelling (% in 24 hours) Of pine lapnik 58 990 17.8 18.3 17.4 90 1100 19,2 16.5 15.9 120 1180 19.6 16,2 15.7 From cedar needles 58 1100 16.9 17.5 16.3 90 1150 17,2 17.3 15.8 120 1200 17.4 16.8 15.3 According to the prototype (p. 31, cf.) 160 1220 17.19 9.33 8.63

The test results show that obtained by the proposed method, wood boards in the process of thermal compaction of wood pulp, at a temperature of its heating is much lower than in similar technical solutions, have a sufficiently high physical and mechanical characteristics. In addition, lowering the temperature regime allows to reduce production costs, and also gives the product useful environmental properties, in the form of a persistent aroma of coniferous forest, favorable for the environment.

Given that the plates according to the proposed method are obtained using widespread logging waste for their production, which contributes to the conservation of forest resources, their deeper processing, due to which the cost of products is quite low, we can conclude that the proposed method for producing wood boards will find wide application in modern production.

Claims (1)

CLAIM A method of obtaining a wood board, which consists in the fact that they take vegetable raw materials in the form of coniferous logging waste and grind it to obtain wood pulp from particles of crushed coniferous logging waste; dried the resulting wood pulp; form dried wood pulp in a flat layer; heating a flat layer of wood pulp and applying force to it to obtain a densified heated flat layer of wood pulp; the compacted heated flat layer of wood pulp is cooled and the force removed from it to produce a wood board, characterized in that the plant material is taken with a wood content of not more than 43 wt.%, the resulting wood pulp is dried to a moisture content of 18-40%, and the flat layer of wood pulp heated to a temperature of 58-120 ° C.