CN109773935B

CN109773935B - Production system and method for improving flame retardant property of oriented strand board by adding flame retardant in multiple stages

Info

Publication number: CN109773935B
Application number: CN201811642378.6A
Authority: CN
Inventors: 范春涛; 朱显龙; 汪运庭; 曾勇
Original assignee: Hubei Bao Yuan Wood Industry Co ltd
Current assignee: Hubei Bao Yuan Wood Industry Co ltd
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2021-06-08
Anticipated expiration: 2038-12-29
Also published as: CN109773935A

Abstract

The invention discloses a production system and a method for improving the flame retardant property of an oriented strand board by adding a flame retardant in multiple stages. This shaving board production system includes: the system comprises a wet flake storage bin, a wet flake conveying device II, a drying device, a dry flake conveying device I, a screening device, a dry flake storage bin, a dry flake conveying device II, a glue mixing device, a paving device, a hot-pressing device, a post-processing device after hot pressing and a fire retardant spraying structure; the fire retardant spraying structure is connected with the wet shaving piece conveying device II, the dry shaving piece conveying device I and/or the dry shaving piece conveying device II, the glue mixing device, the paving device and/or the hot pressing device. The invention adopts multi-process spraying, the flake is fully absorbed, the flame retardant is uniformly distributed, and the loss and waste of the flame retardant caused by unqualified flame retardance of the plate or too much spraying, too late absorption of the surface of the wood shavings and the loss of the flame retardant are avoided. The flame-retardant shaving board obtained by treatment has excellent flame-retardant performance; the physical properties are equivalent to the physical properties of the particle boards produced by pressing with non-added flame retardants.

Description

Production system and method for improving flame retardant property of oriented strand board by adding flame retardant in multiple stages

Technical Field

The invention belongs to the field of wood processing, relates to a machine for wood processing, and particularly relates to a production system and a method for improving the flame retardant property of an oriented strand board by adding a flame retardant in multiple stages.

Background

Oriented Strand Board (OSB) is a board with oriented structure, which is made up of poplar and pine wood through special equipment, slicing, drying, gluing, directional paving and hot pressing. The surface layer flakes are arranged longitudinally, and the core layer flakes are arranged transversely. The criss-cross arrangement recombines the wood texture structure, thoroughly eliminates the influence of the internal stress of the wood on the processing, and ensures that the wood has excellent easy processing property and moisture resistance. The OSB has a directional structure inside, no joint, no gap and no crack, good integral uniformity and extremely high internal bonding strength, so that the OSB is widely developed in recent years.

However, since the conventional oriented strand board has flammability, it has a limitation in applications in many fields. Although the existing oriented strand board generally improves the flame retardant property by adding a flame retardant, the process complexity is very high, or the use of expensive flame retardant causes high cost, and the flame retardant property cannot meet the requirement of higher safety. Therefore, there is a need for improvement in the apparatus and process for manufacturing oriented strand board in order to improve the flame retardancy of oriented strand board and to enable industrial mass production.

Disclosure of Invention

The invention provides a production system of an oriented strand board, which comprises the following components: the device comprises a flaking device, a wet flaking conveying device I, a wet flaking bin, a wet flaking conveying device II, a drying device, a dry flaking conveying device I, a screening device, a dry flaking bin (comprising a surface layer dry flaking bin and a core layer dry flaking bin), a dry flaking conveying device II, a glue mixing device (comprising a surface layer dry flaking glue mixing device and a core layer dry flaking glue mixing device), a paving device, a hot-pressing device, a post-processing device after hot pressing and a flame retardant spraying structure;

the fire retardant spraying structure can be connected with the second wet shaving piece conveying device, the first dry shaving piece conveying device and/or the second dry shaving piece conveying device, the glue mixing device and/or the paving device.

The post-treatment device after hot pressing may include a flame retardant spray structure.

According to the device of the invention, the flame retardant spraying structure can comprise a flame retardant storage tank, a spray head (or an atomizer, a solid feeder) and a flame retardant conveying pipeline which is connected with the flame retardant storage tank and the spray head or connected with the flame retardant storage tank and the atomizer. For example, the flame retardant delivery conduit may be provided with at least one of a mass flow meter, a flow sensor, a pump, a valve (e.g., a gate valve and a ball valve). For another example, the fire retardant conveying pipeline may comprise a conveying trunk and a conveying branch, and the conveying branches are connected in parallel. For another example, the transportation trunk may be provided with a mass flow meter and/or a pump, and the transportation branch may be provided with a flow sensor, a gate valve and/or a ball valve.

According to the device, the flame retardant storage tank can comprise a storage tank body and a stirrer arranged in the storage tank body, wherein the storage tank body is preferably a heat-preservation tank body, and the stirrer is preferably an electric stirrer.

According to the device of the invention, the spray head may be a pressure spray head, for example a pressure atomiser spray head.

According to the device, the flame retardant spraying structure can further comprise a flame retardant preparation tank, and the flame retardant preparation tank is connected with the flame retardant storage tank through a pipeline. Further, the flame retardant formulation tank may include a formulation tank body, a stirrer disposed therein, and a weight transmitter. Preferably, the weight transmitters are uniformly arranged at the bottom of the preparation tank body, the number of the weight transmitters can be one, two or more, and for example, the number of the weight transmitters can be three. Further, a mass flow meter and/or a pump can be arranged on a pipeline connecting the flame retardant preparation tank and the flame retardant storage tank. Further, the stirrer is preferably an electric stirrer. Preferably, the fire retardant preparation tank can be also connected with a water storage tank through a pipeline; preferably, a pump may be provided on a connection line between the fire retardant preparation tank and the water storage tank.

According to the device of the invention, the fire retardant spraying structure connected with the wet shaving piece conveying device II, the dry shaving piece conveying device I and/or the dry shaving piece conveying device II, the glue mixing device and/or the paving device can be one or more selected from a fire retardant spraying structure I, a fire retardant spraying structure II, a fire retardant spraying structure III and a fire retardant spraying structure IV. Preferably, the first flame retardant spraying structure is connected with the second wet shaving piece conveying device; preferably, the second fire retardant spraying structure is connected with the first dry shaving piece conveying device and/or the second dry shaving piece conveying device; preferably, the flame retardant spraying structure III is connected with the glue mixing device; preferably, the fire retardant spraying structure four is connected with the paving device and/or the hot-pressing device.

And the second wet shaving conveying device is a device used in the blanking process and is conveyed out by a wet shaving bin. Preferably, the wet flakes are wet flakes obtained after a flaking process. Preferably, the wet flakes may be wet flakes to which the flame retardant is not attached or attached.

According to the apparatus of the present invention, the flame retardant spraying structure in the post-treatment apparatus after hot pressing may be a flame retardant spraying structure v.

The flame retardant agent spray pattern four and the flame retardant agent spray pattern five of the apparatus of the present invention may be advantageously used to supplement or enhance the surface flame retardant properties of the oriented strand board, as desired.

According to the technical scheme of the device, the first flame retardant spraying structure is connected with the second wet shaving piece conveying device. The second wet shaving piece conveying device comprises a blanking channel, an atomizing cylinder and a spiral extrusion conveying structure;

an atomizing cylinder is arranged below the blanking channel; an atomization structure is arranged in the atomization cylinder;

and a spiral extrusion transmission structure is arranged below the atomizing cylinder.

The first spraying structure can be arranged in the atomizing cylinder and/or the blanking channel.

For example, the nebulizing cartridge includes a barrel and a nebulizing structure within the barrel. Preferably, the cylinder can rotate along the axial direction, and the atomization structure is fixedly arranged. Preferably, the atomizing structure comprises: a fire retardant atomizer and a fire retardant solution conveying pipeline connected with the fire retardant atomizer. Preferably, the fire retardant atomizer is connected with the fire retardant solution storage tank through a fire retardant solution conveying pipeline. In the atomizing structure, the atomizer is arranged on the central axis of the atomizing cylinder. In the atomizing structure, the spraying direction of the atomizer is vertical to the central axis of the atomizing cylinder. In the atomizing structure, the number of the atomizers is selected from 1 to 20, preferably 1 to 10, such as 4, 5, 6, 7, 8. The distance between adjacent atomisers in the atomising structure is 20 to 80cm, preferably 30 to 70cm, for example 50 cm. The planing piece is arranged between the cylinder body of the atomizing cylinder and the atomizing structure. Preferably, the inner wall of the cylinder is further provided with a protruding part. The protruding part can promote the material to be lifted when rotating so as to increase the contact area with the atomized flame retardant.

For example, the screw extrusion transport structure is an extrusion transport screw.

For example, a scattering device may be included in the blanking channel, for example, the scattering device may be a hollow roller or a solid roller; preferably a hollow drum, which may be a breaker roll. And a spray head in the first spraying structure is arranged on the scattering roller. The spraying direction of the spray head is vertical to the central axis of the scattering roller. The number of spray heads is selected from 1 to 30, preferably 2 to 20, such as 5, 10, 15, 20. According to an embodiment of the invention, the distance between adjacent spray heads on the breaker roll is the same or different and is independently selected from 5cm or more, such as 10cm or more, 20cm or more, 30cm or more, 40cm or more, such as 40 cm; for example, the outer surface of the breaking roll is provided with toothed parts which are evenly distributed on the outer surface of the breaking roll. For example, the breaker rollers may each rotate independently. Preferably, the breaking roller can also be electrically connected with a motor.

For example, the number of the flame retardant solution tanks may be one, two, or more; for example 1; as an example, when the number of the flame retardant solution tanks is 1, the spraying structure and the atomizing structure share 1 flame retardant solution tank. Specifically, the flame retardant solution storage tank may separately deliver the flame retardant solution to the spray head and/or the atomizer through the flame retardant solution delivery pipe, respectively.

For example, a distributor can be arranged on the fire retardant conveying pipeline in the first fire retardant spraying structure, the distributor is located between the conveying main road and the conveying branch road, and the distributor is used for conveying the fire retardant solution in the conveying main road to the conveying branch road.

According to the technical scheme of the device, the second flame retardant spraying structure is connected with the first dry shaving piece conveying device. Wherein, dry sliced sheet conveyer one sets up drying device with between the screening plant, dry sliced sheet conveyer still includes: the device comprises a belt, a blanking channel, a scattering device and a spiral extruder; the blanking channel is connected with the belt, and the scattering device is arranged in the blanking channel; the spiral extruder is arranged below the blanking channel. Preferably, the second spraying structure is connected with the inner wall of the blanking channel and/or the scattering device.

The spray head can also be arranged on the inner wall of the blanking channel, such as the upper end, the middle end or the bottom end of the inner wall. Preferably, when the number of the spray heads is two or more, the spray heads can be arranged on the same or different horizontal planes of the inner wall of the blanking channel. Preferably, the setting angle of the spray head is perpendicular to the inner side wall of the blanking channel or the tangent line of the inner side wall and faces inwards. Preferably, when the spray head is arranged at the bottom end of the inner wall of the blanking channel, the included angle between the spray head and the inner wall of the blanking channel is smaller than 90 degrees. Preferably, the spray heads are uniformly distributed on the same or different horizontal planes at the upper end, the middle end or the bottom end of the inner wall of the blanking channel.

According to an embodiment of the present invention, the height of the blanking channel is not particularly limited. The height of the blanking channel can be set by a person skilled in the art according to the field condition, the blanking speed, the required flame retardant adhesion amount and other parameter conditions.

For example, the breaking device may be a device capable of breaking up the flakes, such as a hollow drum. The spray head is arranged on the outer surface of the hollow roller. For example, the outer surface of the hollow roller is also provided with tooth-shaped parts which are uniformly distributed on the outer surface of the hollow roller. For example, the spray heads are uniformly arranged on the outer surface of the hollow drum, and preferably, the distance between adjacent spray heads may be independently selected from 5cm or more, for example, 10cm or more, such as 10cm or more, 20cm or more, 30cm or more, and 40cm or more. For example, the spray head is arranged at an angle perpendicular to a tangent of the outer surface of the hollow drum and the spray head faces away from the outer surface of the hollow drum. Further, the number of the hollow rollers may be one, two or more. Preferably, when the number of the hollow rollers is more than or equal to 3, the distance between every two hollow rollers is the same or different, and is preferably the same. For another example, the hollow drum may be connected to a motor, and the motor drives the hollow drum to rotate.

According to the technical scheme of the device, the second flame retardant spraying structure is connected with the second dry shaving piece conveying device. The second dry shaving piece conveying device can comprise a belt, a scattering device (such as a scattering roller and/or a hollow roller) and a blanking slope; the scattering rollers are uniformly distributed above the blanking slope, and the hollow roller is arranged below the blanking slope. For example, the number of the breaking rollers may be one, two or more; preferably, the number of the scattering rods can be one, two, three, four, five, six or seven; illustratively, the number of the breaking rollers is seven. Preferably, the distance between the central axes of adjacent breaker rolls may be 20-40cm, for example 25-35 cm. Preferably, each breaker roll is independently rotatable. For example, the number of the hollow rollers may be one, two or more.

The second spraying structure comprises a spray head and a fire retardant conveying pipeline, and the spray head can be arranged on the scattering roller and/or the hollow roller.

For example, the spray heads are arranged on any one, two or more scattering rollers and only need to be uniformly distributed; preferably, 2-6 spray heads are uniformly distributed on each scattering roller or every other scattering roller.

For example, the spray heads are arranged on the hollow roller, and preferably the spray heads are uniformly distributed on the hollow roller; preferably, the hollow roller can be further provided with a toothed part, and the toothed part and the spray heads are arranged in a staggered mode. Further, the hollow roller can be electrically connected with a motor (such as a variable frequency motor).

For example, a belt scale is arranged below the blanking part of the second dry shaving piece conveying device, and the shaving pieces sprayed with the flame retardant fall onto the belt scale after passing through the hollow roller. The tail part of the belt scale is provided with a humidity probe for detecting the moisture content of the flame-retardant sliced wood obtained after the flame retardant is sprayed.

According to the technical scheme of the device, the flame retardant spraying structure III is connected with the glue mixing device. One end of the glue mixing device is connected with the upper blanking port, and the other end of the glue mixing device is connected with the lower blanking port. Preferably, the upper blanking port is connected with the belt weigher, and the lower blanking port is connected with the scraper conveyer.

And the fire retardant spraying structure III comprises a fire retardant atomizer, a fire retardant storage tank and a fire retardant conveying pipeline.

For example, the glue mixing device can be a roller type glue mixer, and an adhesive atomizer and a flame retardant atomizer are arranged in the glue mixing device; preferably, the number of the adhesive atomizers and the flame retardant atomizers can be one, two or more; preferably, the adhesive atomizers and the flame retardant atomizers are arranged alternately; preferably, the distance between the adhesive atomizer and the flame retardant atomizer can be 40-100 cm. For example 50-80 cm. In another example, the fire retardant atomizer is connected with the fire retardant storage tank through a fire retardant conveying pipeline.

According to the technical scheme of the device, the flame retardant spraying structure IV is connected with the paving device. The paving device is arranged between the glue mixing device and the hot-pressing device and comprises a slab scale; preferably, the slab scale is uniformly paved with slabs.

Preferably, the distance between the spray head and the plate blank can be 40-50 cm; preferably, the spray heads are arranged in a density, number and spraying range so as to cover the area of the slab. Preferably, the specification of the slab may be: the width is 2.5-2.75m, and the thickness is 60-410 mm; for example, the specifications of the slab may be: the width is 2.56-2.7m, and the thickness is 40-300 mm.

Further, the spray head in the fourth spraying structure is vertically arranged above the slab. Preferably, the fire retardant spraying structure four comprises a first row of spray heads facing the front surface of the plate and a second row of spray heads facing the lower belt on the back surface of the slab. For example, the first row of spray heads is used for spraying the fire retardant to the front side of the slab, and the second row of spray heads is used for spraying the fire retardant to the lower belt on the back side of the slab. Preferably, the arrangement positions of the first row of spray heads and the second row of spray heads, the number of spray heads and the positions of the spray heads may be staggered with each other. Preferably, the spraying direction of the fire retardant of the first row of spray nozzles is vertical to the surface of the slab, and the spraying direction of the fire retardant of the second row of spray nozzles is vertical to the surface of the lower belt on the back surface of the slab.

According to the technical scheme of the device, the post-treatment device after hot pressing comprises a flame retardant spraying structure V, and the flame retardant spraying structure V further comprises a travel switch I and a travel switch II.

The first travel switch and the second travel switch are used for detecting the movement position of the plate. When the plate is detected to enter a flame retardant spraying area, spraying the flame retardant; and when the board is detected to leave the flame retardant spraying area, stopping spraying the flame retardant.

And the fire retardant spraying structure five comprises a first row of spray heads facing the front surface of the plate and a second row of spray heads facing the back surface of the plate. For example, the first row of spray heads is used for spraying the fire retardant to the front side of the plate, and the second row of spray heads is used for spraying the fire retardant to the back side of the plate. Preferably, the arrangement positions of the first row of spray heads and the second row of spray heads, the number of spray heads and the positions of the spray heads can correspond to or be staggered with each other. Preferably, the spraying direction of the fire retardant of the first row of spray heads and the second row of spray heads is perpendicular to the surface of the plate.

According to the device, the oriented strand board production system can further comprise a PLC (programmable logic controller), and the PLC can be electrically connected with the pump, the mass flow meter, the flow sensor, the ball valve, the gate valve, the motor, the travel switch I and the travel switch II.

According to the device, the fire retardant conveying pipeline, the connecting pipeline of the fire retardant preparation tank and the fire retardant storage tank, and the connecting pipeline of the fire retardant preparation tank and the water storage tank can be made of stainless steel.

According to the device of the invention, the fire retardant spraying structures can be sprayed four and/or five by arranging a pump on the fire retardant conveying pipeline and/or introducing compressed air.

According to the device of the invention, the pump may be a vane pump.

Further, the invention also provides a method for improving the flame retardant property of the oriented strand board by adopting the oriented strand board production system, which comprises the following steps: in the wet shaving transfer process, the dry shaving transfer process, the glue mixing process and the post-treatment process, a flame retardant solution is sprayed to the shavings. The wet shaving conveying process may include a process before wet shaving is conveyed out of the wet shaving bin, passes through the blanking channel and the atomizing cylinder, and enters the screw extrusion structure. Wherein the dry shaving transfer process may include a transfer process of the dry shaving prior to entering the dry shaving bin, and/or a transfer process of the dry shaving from the dry shaving bin to the size mixing process. Wherein the post-treatment process may include a treatment process after the hot pressing.

According to the technical scheme of the invention, the method comprises the following steps:

(1) spraying fire retardant solution to the wet shaving pieces conveyed from the wet shaving piece bin in the blanking process, and drying the wet shaving pieces;

(2) after the sliced sheets obtained in the step (1) are dried, spraying a flame retardant solution to the falling dry sliced sheets in a blanking channel before the dry sliced sheets enter a dry sliced sheet storage bin, and then sequentially entering the dry sliced sheet storage bin and then entering a glue mixing device; and/or the presence of a gas in the gas,

(3) directly feeding the dried sliced sheets obtained in the step (1) into a dry sliced sheet storage bin after drying, spraying a flame retardant solution on the dry sliced sheets in the conveying process while scattering the dry sliced sheets before the dry sliced sheets are fed into a glue mixing process, and feeding the dry sliced sheets into a glue mixing device;

(4) after the dry sliced sheets enter the glue mixing device, spraying a flame retardant and an adhesive to the sliced sheets at the same time, and sending the sliced sheets to a paving procedure after the spraying is finished;

(5) spraying a flame retardant solution on the surface of the plate blank and the belt in the paving procedure, and performing hot pressing on the plate blank after spraying to obtain a flame-retardant oriented strand board; and/or the presence of a gas in the gas,

(6) and (4) after the step (4) is finished, the plate obtained by paving enters a hot pressing process, and flame retardant solution is sprayed on the front surface and the back surface of the plate in a post-treatment process after hot pressing to obtain the flame-retardant oriented strand board.

Preferably, the flame retardant solution is sprayed in an area capable of covering the shaving sheet.

According to the method of the present invention, the wood may be selected from wood suitable for preparing particle board, for example, may be at least one of pine, eucalyptus, poplar, paulownia, and the like.

According to the method of the present invention, the specifications of the flakes are not particularly limited. By way of example, the width of the flakes may be 5-40mm, such as 10-30 mm; the thickness may be 0.4-0.8mm, for example 0.5-0.7 mm; the length may be 100-180mm, such as 120-160 mm.

According to the process of the present invention, in steps (1), (2), (3) and (4), the flame retardant may be selected from any one, two or more of the water-soluble flame retardants known in the art. For example, the flame retardant may contain at least one of ammonium polyphosphate, ammonium phosphate, ammonium sulfate, borax, ammonium sulfamate, sodium phosphate, guanylurea phosphate, guanidine sulfamate, polyphosphazene, guanidine dihydrogen phosphate, diguanidine hydrogen phosphate, guanidine sulfate, and the like; preferably, the flame retardant may be ammonium polyphosphate, a mixture of ammonium phosphate and ammonium sulfate, borax, ammonium sulfamate, a mixture of sodium phosphate and ammonium phosphate, a mixture of guanylurea phosphate, boric acid, borax, and/or guanidine sulfamate. Illustratively, the flame retardant may contain ammonium polyphosphate (e.g., ammonium polyphosphate having a polymerization degree of less than 20, e.g., 6, 8, 10), ammonium phosphate and ammonium sulfate, for example, in a mass ratio of (1-3): 1 (e.g., ammonium polyphosphate having a polymerization degree of less than 20, e.g., 6, 8, 10), ammonium phosphate and ammonium sulfate; illustratively, the flame retardant may contain borax, ammonium sulfamate, sodium phosphate, and ammonium phosphate, for example, in a mass ratio of 2:3:2: 3. The concentration of flame retardant in the flame retardant solution may be 10-40 wt%, for example 15-35 wt%, 25-32 wt%. Preferably, the temperature of the flame retardant solution may be 10-45 deg.C, such as 20-35 deg.C.

According to the method of the invention, in the step (1), the flame retardant is attached to the flame retardant flaked pieces, and the attachment amount of the flame retardant can be 10-20%, such as 13-18% and 14-16%; the weight of the flame retardant is the weight percentage of the flame retardant attached to the wood chips after the flame retardant is sprayed to the absolutely dry wood chips, wherein the weight of the flame retardant is calculated by the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the spraying amount of the flame retardant solution may be 20 to 90L/min; for example, the spraying amount may be 35-85.4L/min, 30-82L/min, 70-80L/min.

For example, the water content of the flakes prior to spraying the flame retardant solution is 30 to 50 wt%, such as 35 to 47 wt%. After spraying the fire-retardant solution, the moisture of the flakes may be 35-55 wt%, for example 40-55 wt%.

The pressure of the extrusion may be from 1N to 50N, preferably from 1N to 20N, for example 10N; the pressing time may be 1 to 7 seconds, preferably 3 to 5 seconds.

In step (2) according to the method of the invention, the water content of the dry sliced flakes may be 2.0 to 3.5 wt%, for example the water content may be 3.0 wt%, 3.1 wt%, 3.2 wt%, 3.3 wt%, 3.4 wt%.

For example, the flame retardant may be sprayed onto the dry flakes in an amount such that the weight of flame retardant sprayed onto the flakes is from 1.0 to 3.0 wt%, such as from 1.5 to 2.5 wt%, such as from 1.8 to 2.1 wt%, based on the weight of the dry flakes; wherein the weight of the flame retardant is based on the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the spraying amount of the flame retardant solution may be 7 to 30L/min; for example, the spraying amount may be 9-12L/min, 15-25L/min.

For example, the flame retardant solution can be sprayed while being scattered in the blanking channel. Preferably, the breaking up speed may be 20-50 rpm.

For example, the dry-shaving sheets have a water content of 6 to 8 wt.%, such as 6.5 to 7.5 wt.%, after spraying the flame retardant.

According to the method of the present invention, in the step (3), the flame retardant is sprayed and attached to the flakes, and the attached amount of the flame retardant is the weight percentage of the flame retardant attached to the flakes after spraying, such as 1.0-3.5%, such as 1.6-3.0, 1.8-2.5%; wherein the weight of the flame retardant is based on the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the break up speed may be 20-50 rpm with a delivery time of 3-5 seconds.

For example, the dry flakes have a moisture content of no more than 10 wt%, such as 4-8 wt%, 5-7.5 wt%, after spraying the flame retardant.

According to the method of the present invention, in the step (4), the spraying amount of the flame retardant may be 5 to 30L/min, such as 8 to 12L/min, 15 to 25L/min. For example, the flame retardant may be sprayed onto the flakes in an amount such that the weight of flame retardant sprayed onto the flakes is from 1.5% to 6%, such as from 2% to 5%, such as from 2% to 3%, by weight of the dry flakes; wherein the weight of the flame retardant is based on the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the adhesive may be selected from adhesives conventional in the art, and may be, for example, a polymeric isocyanate. The mass ratio of the adhesive to the flame retardant may be 1 (0.1-3), such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, such as 1 (0.3-0.6), e.g. 9: 4.

For example, after the flame retardant and adhesive are sprayed, the moisture content of the flakes is 4-12%, such as 5-11%.

According to the method of the present invention, in the step (5) and the step (6), the flame retardant may be selected from guanylurea phosphate in combination with at least one of boric acid, borax, and guanidine sulfamate. For example, the mass ratio of the two may be: phosphoric acid guanylurea: (at least one of boric acid, borax, and guanidine sulfamate) ═ 6-8: (2-4). For another example, the temperature of the flame retardant may be 45-55 ℃. The concentration of flame retardant in the flame retardant solution is 15 to 35 wt%, such as 25 to 32 wt%.

According to the method of the present invention, the spraying amount of the flame retardant solution in step (5) may be 3 to 10L/min, for example, 4 to 6L/min.

For example, the flame retardant may be sprayed onto the flakes in an amount such that the weight of the flame retardant sprayed onto the flakes is from 0.8% to 2%, such as from 0.9% to 1.2%, by weight of the dry flakes; wherein the weight of the flame retardant is based on the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the water content of the flakes after spraying of the fire retardant is 9-15 wt%, such as 10-13 wt%.

According to the method of the present invention, in the step (6), the flame retardant solution may be sprayed in an amount of 0.3 to 2L/min, for example, 0.8 to 1.5L/min.

For example, the flame retardant may be sprayed onto the flakes in an amount such that the weight of flame retardant sprayed onto the flakes is from 0.1 to 0.4 wt%, such as from 0.15 to 0.3 wt%, based on the weight of the absolutely dry flakes; wherein the weight of the flame retardant is based on the solid flame retardant. The attachment includes adsorption, wetting or otherwise bonding to the surface of the flakes and to the interior thereof.

For example, the oriented strand board has a moisture content of 3 to 7 wt%, e.g., 4 to 6.5 wt%, after the flame retardant spraying is completed.

For example, the hot pressing pressure of the hot pressing process may be 2.0 to 3.5N/mm²E.g. 2.5-3.0N/mm². The inlet temperature of the hot pressing process may be 235-245 ℃, such as 237-243 ℃. The outlet temperature of the hot pressing process may be in the range of 90-100 c, for example 93-97 c. The time of the hot pressing process can be 115-.

According to the method, in each step, the spraying amount is adjusted by a speed-adjustable pump; preferably, the readings indicated by the flow meter are the amount sprayed.

The invention has the beneficial effects that:

the invention creatively provides that an additional fire retardant spraying procedure is added in the wet flaking procedure, so that the contact time of the flaked pieces and the fire retardant in the whole process is integrally improved, the fire retardant is more fully absorbed and uniformly distributed, and the loss and waste of the fire retardant caused by the contact of the flaked piece surfaces with excessive fire retardant in individual procedures are avoided. The finished board obtained by the device and the process has the advantages of low moisture regain, no migration, no precipitation, mildew resistance, no corrosion and good color stability. The flame-retardant oriented shaving board treated by the device and the process has excellent flame-retardant performance, and the flame-retardant performance grade reaches the flame-retardant B1 grade; the oriented shaving board has good environmental protection performance and does not contain formaldehyde; the physical property is equivalent to that of an OSB2 plate, and the corrosion resistance and the water absorption thickness expansion rate are low.

Drawings

Fig. 1 is a schematic structural view of an oriented strand board production system according to embodiment 1 of the present invention;

fig. 2 is a schematic structural view of a second wet shaving board conveying device connected with a first spraying structure in the oriented strand board production system in the embodiment 1 of the invention;

fig. 3(a) is a schematic structural view of a first dry shaving sheet conveying device connected with a second spraying structure in the oriented strand board production system in the embodiment 1 of the invention;

fig. 3(B) is a schematic structural view of the blanking port in fig. 3 (a).

Fig. 4 is a schematic structural view of a second dry shaving board conveying device connected with a second spraying structure in the oriented strand board production system in the embodiment 1 of the invention.

Fig. 5 is a schematic structural view of a glue mixing device connected with a third spraying structure in the particle board production system in the embodiment 1 of the invention.

Fig. 6 is a schematic structural view of a paving device connected with a fourth spraying structure in the oriented strand board production system in the embodiment 1 of the invention.

Fig. 7 is a schematic structural view of a hot pressing device connected with a spraying structure five in the directional shaving board production system in the embodiment 1 of the invention.

Reference numerals: 1-belt, 2-blanking port, 3-blanking channel, 4-hollow roller, 5-pressure nozzle, 6-dentate part, 7-variable frequency motor, 8-screw extruder, 9-fire retardant storage tank, 10-electric stirrer, 11-conveying trunk, 12-conveying branch, 13-flow sensor, 14-impeller pump, 15-ball valve, 16-belt scale, 17-mass flowmeter, 18-gate valve, 19-pump, 20-dry shaving stock bin, 21-humidity probe, 22-adhesive atomizer, 23-fire retardant atomizer, 24-upper blanking port, 25-blanking port, 26-scraper conveyor, 27-slab, 28-slab, 29-plate, 30-first row nozzle, 31-first row of spray heads, 32-first travel switch, 33-second travel switch, 34-scattering roller, 35-wet shaving stock bin, 36-atomizing cylinder and 37-distributor.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that various changes or modifications can be made by those skilled in the art after reading the disclosure of the present invention, and such equivalents also fall within the scope of the invention.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.

Flame retardant solution a used in the following examples: according to the mass ratio of borax: ammonium sulfamate: sodium phosphate: and adding water to prepare a flame retardant solution A, wherein the ammonium phosphate is 2:3:2: 3.

Flame retardant solution B used in the following examples: phosphoric acid guanylurea and boric acid in a mass ratio of 7: 3 mixing, adding water to prepare a flame retardant solution B.

The flow sensor used in the embodiment is DC-PNP, the pump is MJ083BY0 and NM021BY, the impeller pump is 50FSB-ZZ, the pressure spray head is W-2.0, the power of the motor is 1.1kW, the variable frequency motor is YVF2-132S-4(2.2kW) and NM021BY0432B, the mass flow meter is YKD99Z, the weight transmitter is RWT-100A, the travel switch I and the travel switch II are LX19-051, the adhesive atomizer is E1-4, and the flame retardant atomizer is E1-4.

Unless otherwise indicated, percentages hereinafter refer to weight percentages.

Example 1

The production system for improving the flame retardant property of the oriented strand board by adding the flame retardant in multiple stages as shown in figure 1 comprises: the device comprises a flaking device, a wet flaking conveying device I, a wet flaking bin, a wet flaking conveying device II, a drying device, a dry flaking conveying device I, a screening device, a dry flaking bin, a dry flaking conveying device II, a glue mixing device, a paving device, a hot pressing device, a post-treatment device after hot pressing and a fire retardant spraying structure;

the first flame retardant spraying structure is connected with the wet shaving piece conveying device and the second flame retardant spraying structure is connected with the first dry shaving piece conveying device and/or the second dry shaving piece conveying device, the third flame retardant spraying structure is connected with the glue mixing device, and the fourth flame retardant spraying structure is connected with the paving device. And the second wet shaving conveying device is a device used for conveying out the wet shaving stock bin in the blanking process and the stirring process of the atomizing cylinder. The wet sliced sheet is obtained through a slicing process. And the flame retardant spraying structure in the post-treatment device after hot pressing is a flame retardant spraying structure V.

Flame retardant spray pattern four and flame retardant spray pattern five are advantageously used to supplement or enhance the surface layer flame retardant properties of oriented strand board.

Screening plant includes top layer dry shaving screening plant and sandwich layer dry shaving screening plant, and the dry shaving feed bin divide into top layer dry shaving feed bin and sandwich layer dry shaving feed bin, and the glue mixing device divide into top layer dry shaving glue mixing device and sandwich layer dry shaving glue mixing device.

And the fire retardant spraying structures from one to five comprise a fire retardant storage tank, a pressure nozzle or a fire retardant atomizer, and a fire retardant conveying pipeline which is connected with the fire retardant storage tank and the pressure nozzle and connected with the fire retardant storage tank and the fire retardant atomizer. At least one of a mass flow meter, a flow sensor, a pump and a valve (e.g., a gate valve or a ball valve) is disposed on the fire retardant conveying pipe. The fire retardant conveying pipeline comprises a conveying main road and a conveying branch road, and the conveying branch road is connected in parallel. The conveying trunk is provided with a mass flow meter and/or a pump, and the conveying branch is provided with a flow sensor, a gate valve and/or a valve.

As shown in fig. 2, the first fire retardant spraying structure is connected with the second wet shaving conveyor, which comprises a blanking channel 3, a scattering roller 34, an atomizing cylinder 36 and a screw extruder 8; a mixing drum 36 is connected below the blanking channel 3, an atomization structure is arranged in the atomization drum 36, and a spiral extruder 8 is arranged below the atomization structure.

The first flame retardant spraying structure is connected with the scattering roller 34 and the atomizing cylinder.

The spraying direction of the pressure nozzle 5 in the first fire retardant spraying structure is vertical to the central axis of the scattering roller 34. The number of the pressure nozzles arranged on the scattering roller 34 was 6, and the distance between adjacent nozzles was 50 cm. The outer surface of the breaking roll 34 is provided with the tooth-shaped parts 6, and the tooth-shaped parts 6 are uniformly distributed on the outer surface of the breaking roll 34. The breaking roller 34 is also electrically connected with the variable frequency motor 7.

The atomization structure comprises a flame retardant atomizer 23, the flame retardant atomizer 23 is arranged on the central axis of the mixing drum 36, and the injection direction of the flame retardant atomizer 23 is perpendicular to the central axis of the mixing drum 36. The number of the flame retardant atomizers 23 is set to 6. The distance between adjacent atomizers was 50 cm.

The spraying structure I and the atomizing structure share one fire retardant solution storage tank. The fire retardant solution storage tank is used for conveying the fire retardant solution to the spray head and the atomizer through the fire retardant solution conveying pipeline respectively.

A distributor 37 is arranged on a fire retardant conveying pipeline in the first fire retardant spraying structure, the distributor 37 is located between the conveying main road and the conveying branch road, and the distributor is used for conveying fire retardant solution in the conveying main road to the conveying branch road.

As shown in FIG. 3(A), the second fire retardant spraying structure is connected with the first dry shaving piece conveying device. Wherein, dry shaving piece conveyer sets up between drying device and screening plant, and dry shaving piece conveyer includes: the device comprises a belt 1, a blanking channel 3, a hollow roller 4 and a spiral extruder 8; the blanking channel 3 is connected with the belt 1, and the two hollow rollers 4 are arranged in the blanking channel 3; the screw extruder 8 is arranged below the blanking channel 3. And the flame retardant spraying structure II is connected with the blanking port 2 of the blanking channel 3 and the hollow roller 4.

And the pressure nozzles 5 in the flame retardant spraying structure II are uniformly arranged on the outer surface of the hollow roller 4. The pressure spray heads 5 are arranged at an angle vertical to the tangent line of the outer surface of the hollow roller 4, the pressure spray heads 5 face away from the outer surface of the hollow roller 4, and the distance between the adjacent spray heads is selected from 30 cm. The hollow drum 4 is also provided with evenly distributed toothed parts 6 on its outer surface. The hollow drum 4 is connected with a variable frequency motor 7, and the variable frequency motor 7 drives the hollow drum 4 to rotate.

As shown in fig. 3(B), the pressure nozzle 5 in the second flame retardant spraying structure is further disposed on the inner wall (three planes of the upper end, the middle end and the lower end of the inner side wall) of the blanking channel 3 and the top of the blanking port 2 of the blanking channel 3. When the pressure nozzle 5 is arranged on the inner wall of the blanking channel 3, the arrangement angle of the pressure nozzle 4 is perpendicular to the inner wall of the blanking channel 19 or the tangent line of the inner wall and sprays towards the dry sliced sheets. When the pressure nozzle 5 is arranged at the top of the blanking port 2, the arrangement angle of the pressure nozzle 5 is vertical to the plane at the top of the blanking port 2, and the nozzle faces downwards. The pressure nozzles 5 are uniformly distributed on the inner wall of the blanking channel 3 and the top of the blanking port 2.

As shown in the device of FIG. 4, a second fire retardant spraying structure is connected with a second dry shaving piece conveying device. The second dry sliced sheet conveying device is connected with a dry sliced sheet storage bin 20 and comprises a belt 1, a scattering roller 34, a blanking slope and a hollow roller 4;

the scattering rollers 34 are uniformly distributed above the blanking slope, and the hollow drum 4 is arranged below the blanking slope. The number of the scattering rollers is that the distance between the central axes of seven adjacent scattering rollers is 30cm, and each scattering roller can independently rotate; the number of the hollow rollers is one.

The pressure nozzles 5 in the third flame retardant spraying structure are arranged on each scattering roller 34, and as shown in fig. 4, 4 pressure nozzles are uniformly distributed on each scattering roller 34.

The pressure nozzles 5 are also uniformly arranged on the hollow roller 4, the hollow roller 4 is also provided with a toothed part 6, and the toothed part 6 and the pressure nozzles 5 are staggered. The hollow roller 4 is also electrically connected with a variable frequency motor 7.

And a belt scale 16 is arranged below the blanking part of the second dry shaving piece conveying device, and the shaving pieces sprayed with the flame retardant fall on the belt scale 16 after being scattered by the hollow roller 4. The tail part of the belt weigher 16 is provided with a humidity probe 21 for detecting the water content of the flame-retardant sliced sheet obtained after the flame retardant is sprayed.

And the dry shaving stock bin comprises a surface layer dry shaving stock bin and a core layer dry shaving stock bin, correspondingly, the dry shaving conveying device II also comprises a surface layer dry shaving conveying device II and a core layer dry shaving conveying device II, and the surface layer dry shaving conveying device II is connected with the flame retardant spraying structure III.

In the device shown in fig. 5, the fire retardant spraying structure III is connected with the glue mixing device. One end of the glue mixing device is connected with an upper blanking port 24, and the other end is connected with a lower blanking port 25. The upper material dropping port 25 is connected with the belt weigher 16, and the material dropping port 25 is connected with the scraper conveyer 26.

The glue mixing device adopts a roller type glue mixer, and an adhesive atomizer 22 and a flame retardant atomizer 23 are arranged in the glue mixing device; the number of the adhesive atomizers 22 and the number of the flame retardant atomizers 23 are respectively 3, and the adhesive atomizers and the flame retardant atomizers are arranged alternately. The fire retardant atomizer 23 is connected with the fire retardant storage tank 9 through a fire retardant delivery pipeline. The adhesive atomizer 22 is connected with the adhesive storage tank through an adhesive conveying pipeline.

And the third flame retardant spraying structure comprises a flame retardant atomizer 30, a flame retardant storage tank 9 and a flame retardant conveying pipeline.

Wherein, the glue mixing device is divided into a surface layer shaving glue mixing device and a core layer shaving glue mixing device, and the surface layer glue mixing device and the core layer glue mixing device are connected with a flame retardant spraying structure in four phases.

In the device shown in fig. 6, the fire retardant spraying structure four is connected with the paving device. The paving device is arranged between the glue mixing device and the hot-pressing device and comprises a slab balance 28; the slab 27 is uniformly laid on the slab scale 28. The fire retardant spraying structure four comprises a first row of pressure nozzles 5 facing the front side of the plate and a second row of pressure nozzles 5 facing the lower belt on the back side of the plate blank, wherein the first row of pressure nozzles 5 are vertically arranged above the plate blank 27 and used for spraying the fire retardant to the front side of the plate blank. And the second row of pressure nozzles 5 are used for spraying a fire retardant to the belt at the lower part of the back surface of the plate blank. The distance between the pressure nozzle and the plate blank is 45 cm; the density, number and spray range of the pressure nozzles 5 are set to cover all slabs 27. The specification of the plate blank is as follows: the width is 2.56-2.7m, and the thickness is 40-300 mm.

As shown in the apparatus of fig. 7, a flame retardant spraying structure five is included in the post-treatment apparatus after the hot pressing, and the fifth flame retardant spraying structure further includes a first stroke switch 32 and a second stroke switch 32. The flame retardant spraying area includes a first row of spray heads 30 facing the front surface of the sheet 29 and a second row of spray heads 31 facing the rear surface of the sheet 29. The first row of spray heads 30 is used for spraying the fire retardant to the front surface of the plate 29, and the second row of spray heads 31 is used for spraying the fire retardant to the back surface of the plate 29. The positions where the first row 30 and the second row 31 are disposed, the number of pressure heads 4, and the positions of the pressure heads correspond to each other. The flame retardant is sprayed in the direction perpendicular to the surface of the plate 29 by the first row of spray heads 30 and the second row of spray heads 31.

The first travel switch 32 and the second travel switch 33 are used for detecting the moving position of the plate 29. When the plate 29 is detected to enter the flame retardant spraying area, the flame retardant starts to be sprayed; when the sheet 29 is detected to leave the flame retardant spraying area, the flame retardant spraying is stopped.

The flame retardant spraying structure I to V further comprises a flame retardant preparation tank, and the flame retardant preparation tank is connected with the flame retardant storage tank through a pipeline. The fire retardant preparation tank comprises a preparation tank body, an electric stirrer and three weight transmitters, wherein the weight transmitters are uniformly arranged at the bottom of the preparation tank body, and the number of the weight transmitters is three. And a pipeline for connecting the fire retardant preparation tank and the fire retardant storage tank is also provided with a mass flow meter, a gate valve, a ball valve and/or an impeller pump.

The fire retardant preparation tank is also connected with the water storage tank through a pipeline, and an impeller pump is arranged on a connecting pipeline of the fire retardant preparation tank and the water storage tank.

The shaving board production system further comprises a PLC, and the PLC is electrically connected with the pump, the impeller pump, the mass flow meter, the flow sensor, the ball valve, the gate valve, the variable frequency motor, the humidity probe, the first travel switch and the second travel switch.

The fire retardant conveying pipeline, the connecting pipeline of the fire retardant preparation tank and the fire retardant storage tank, and the connecting pipeline of the fire retardant preparation tank and the water storage tank are all made of stainless steel.

Example 2

The specification of the sliced sheets is as follows: 5-40mm in width, 0.4-0.8mm in thickness and 180mm in length.

A method for improving the flame retardant performance of oriented strand board using the production system of example 1, the method comprising the steps of:

(1) spraying a flame retardant solution A (the temperature of the flame retardant solution A is 25 +/-5 ℃) to the wet sliced sheets in the blanking process and the stirring process of the atomizing cylinder, and drying the sliced sheets conveyed from the wet sliced sheet bin;

(2) after drying the sliced sheets sprayed with the flame retardant A, before the sliced sheets enter a dry sliced sheet storage bin, spraying a flame retardant solution A to the falling dry sliced sheets in a blanking channel and a blanking port; the sliced sheets sprayed with the fire retardant enter a dry sliced sheet storage bin, and the dry sliced sheets conveyed out from the dry sliced sheet storage bin enter a glue mixing process;

the temperature of the flame retardant solution A is 25 +/-5 ℃;

feed amount (measured by absolutely dry shavings) at the blanking port: the feeding amount of the surface layer shaving piece and the core layer shaving piece is 5 t/h;

scattering the sliced sheets in the blanking channel at a speed of 20-30 r/min;

(3) spraying a flame retardant solution A (with the temperature of 25 +/-5 ℃) and an adhesive solution to the sliced sheets simultaneously in the glue mixing procedure;

the adhesive used in the step is as follows: the polymeric isocyanate, the glue application amount is 4.5 percent of the mass of the oven-dried sliced sheet.

The mass ratio of the total amount of the adhesive to the flame retardant is 9: 4.

(4) The sliced sheets conveyed out of the glue mixing device enter a paving procedure to form a plate blank, the running speed of the plate blank is 170mm/s, and a flame retardant solution B (the temperature is 50 ℃) is sprayed on the plate blank; and (5) carrying out hot pressing to obtain the flame-retardant oriented strand board.

The spraying amount of the fire retardant (i.e., the pump flow), the concentration of the fire retardant solution, the water content of the wood chips before and after spraying the fire retardant, the adhesion amount of the fire retardant, and the fire retardancy test results of the wood chips in each process are shown in table 2.

Example 3

Example 3 the procedure of example 2 was followed, wherein the spraying amount of the flame retardant (i.e., the pump flow), the concentration of the flame retardant, the water content of the chips before and after spraying the flame retardant, the adhesion amount of the flame retardant, and the measurement results of the flame retardancy of the chips in each procedure are shown in Table 3.

Example 4

(2) drying the sliced sheets sprayed with the flame retardant solution A, then conveying the dried sliced sheets into a dry sliced sheet storage bin, and spraying the flame retardant solution A on the dried sliced sheets in the conveying process while scattering the dried sliced sheets before the dried sliced sheets enter a glue mixing process;

the temperature of the flame retardant solution A is 25 +/-5 ℃;

the scattering speed is 20-30 r/min;

(3) in the glue mixing procedure, spraying a flame retardant solution A (with the temperature of 25 +/-5 ℃) and an adhesive solution to the sliced sheets at the same time;

(4) After the step (3) is finished, performing a hot-pressing process, performing hot pressing on the plate blank to obtain a plate, and spraying a flame retardant solution B (at the temperature of 50 ℃) on the front surface and the back surface of the plate in a post-treatment process to obtain a finished flame-retardant oriented strand board; the hot pressing pressure of the hot pressing process is 3N/mm²Inlet, inletThe temperature was 240 ℃ and the exit temperature 95 ℃ for 250 s.

The spraying amount of the fire retardant (i.e., the pump flow), the concentration of the fire retardant, the water content of the chips before and after spraying the fire retardant, the adhesion amount of the fire retardant, and the fire retardancy of the chips in each process are shown in table 4.

Example 5

Example 5 was conducted in the same manner as in example 4, wherein the spraying amount of the flame retardant (i.e., the pump flow rate), the concentration of the flame retardant, the water content of the chips before and after spraying the flame retardant, the adhesion amount of the flame retardant, and the results of the measurement of the flame retardancy of the chips in each step are shown in Table 5.

The physical property data (physical properties measured in GB/T17657-2013) of the finished flame-retardant OSB panels obtained in examples 2-5 are shown in Table 6.

Thirdly, testing other performances of the shaving sheet and the finished product in the process according to the following method:

1. flame retardant spraying uniformity and coverage rate of flame retardant shaving sheet

(1) The flame-retardant chips are distinguished by adding a red coloring agent into a flame retardant storage tank, wherein the addition amount of the red coloring agent is 1 kilogram of coloring agent added into each cubic meter of flame retardant solution, and the storage amount of the flame retardant in the storage tank is controlled before detection, so that the storage amount of the flame retardant is about 10 minutes of usage amount.

(2) After each procedure of adding the flame retardant in the examples, sampling is carried out for a plurality of times respectively, the sampling interval time is 3-4 minutes, the number of the sliced sheets for each sampling is 50, and the area of the sliced sheets is required to be more than 40% of that of the standard sliced sheets (the size of the standard sliced sheets: 120mm multiplied by 20 mm).

(3) And (3) uniformity detection: and observing the covering condition of the flame retardant on each sliced sheet through the surface color of the sliced sheet, and judging that the spraying uniformity of the sliced sheet is unqualified when the surface area of the part with the color difference of the sliced sheet is more than 30 percent of the total surface area of the whole sliced sheet.

Uniformity is expressed as the ratio of uniformity acceptable flakes to total number of flakes:

uniformity (number of uniform acceptable shavings/total number of shavings) × 100%.

(4) Coverage rate: and observing the covering condition of the fire retardant on each sliced sheet through the surface color of the sliced sheet, and judging that the sliced sheet is unqualified in spraying and covering when the area of the part of the sliced sheet which is not dyed is more than 10% of the total surface area of the whole sliced sheet. Coverage is judged by coverage rate:

coverage ═ 100% (number of covered acceptable shavings/total number of shavings).

2. Amount of flame retardant

And calculating the using amount of the flame retardant by detecting the change of the water content of the sliced sheets before and after spraying.

(1) And (3) detecting the concentration of the flame retardant: about 50g of flame retardant solution is taken from a production line, 2g of the flame retardant solution is taken from 50g of the flame retardant solution and dropped into a watch glass, the watch glass is placed into an oven at 50 +/-5 ℃ for drying for 2 hours, and the solid content is calculated. The flame retardant solids content is designated a.

(2) Determination of water content of the sliced sheets before spraying the flame retardant in each process: the samples were taken several times, 30 seconds apart, 3 times apart, and mixed well before proceeding this procedure. Randomly selecting 10 sliced sheets (the area is not less than 40% of the area of the standard sliced sheet) from the uniformly mixed sliced sheets, putting the sliced sheets into a rapid moisture tester, measuring the moisture content at 100 +/-2 ℃ for 10 minutes, and recording as the moisture content b.

(3) And (3) determining the water content of the flame-retardant sliced sheets: after each procedure of adding the flame retardant in the examples, samples were taken for a plurality of times at intervals of 30 seconds, and the samples were taken for 3 times, followed by uniform mixing. Randomly selecting 10 sliced sheets (the area is not less than 40% of the area of the standard sliced sheet) from the uniformly mixed sliced sheets, putting the sliced sheets into a rapid moisture tester, and measuring the moisture content at 100 +/-2 ℃ for 10 minutes, wherein the moisture content is marked as c.

(4) The flame retardant adhesion (weight percentage of extra flame retardant adhered to the wood chips after each flame retardant spraying in the absolutely dry wood chips) is calculated as follows:

the formula x ═ c-b) × a/((1-b) × (1-a-c)) × 100% was calculated.

Calculating the use amount of the fire retardant at the glue mixer through detecting the change of the water content of the sliced sheets before and after spraying:

(1) and (3) detecting the concentration of the flame retardant: about 50g of flame retardant solution is taken from a production line, 2g of the flame retardant solution is taken from 50g of the flame retardant solution and dropped into a watch glass, the watch glass is placed into an oven at 50 +/-5 ℃ for drying for 2 hours, and the solid content is calculated. The flame retardant solids content is noted as m.

(2) And (3) determining the moisture content of the sliced pieces before entering a glue mixer: the samples were taken several times, separated by 30 seconds and divided into 3 times, and mixed well before the procedure. Randomly selecting 10 sliced sheets (the area is not less than 40% of the area of the standard sliced sheet) from the uniformly mixed sliced sheets, putting the sliced sheets into a rapid moisture tester, measuring the moisture content at 100 +/-2 ℃ for 10 minutes, and recording the moisture content as n.

(3) And (3) determining the water content of the flame-retardant sliced sheets: and (3) sampling for multiple times at a detection gate of a feed opening of the glue mixer at intervals of 30 seconds, and uniformly mixing. Randomly selecting 10 sliced sheets (the area is not less than 40% of the area of the standard sliced sheet) from the uniformly mixed sliced sheets, putting the sliced sheets into a rapid moisture tester, and measuring the moisture content at 100 +/-2 ℃ for 10 minutes, wherein the moisture content is recorded as p.

(4) The size applied by the size mixer is in d units (%), and the weight percentages of the applied size and the oven dried chips are expressed.

(5) The adhesion amount of the flame retardant sprayed at the current stage (the weight of the flame retardant adsorbed to the sliced sheet accounts for the weight percent of the absolutely dry sliced sheet after the spraying of the flame retardant) is calculated according to the following formula:

x＝(p-n/(1+d))×m/((1-n/(1+d))×(1-m-p))×100％。

3. flame retardant effect detection of flame retardant shaving sheet

The detection method comprises the following steps:

(1) and (3) baking the flame-retardant sliced sheets in an oven at 100 +/-2 ℃ for 10 minutes, then putting the flame-retardant sliced sheets on an alcohol lamp for combustion, visually judging the time required by ignition of the sliced sheets, and recording as the flame-retardant time. And judging whether the sliced sheet achieves the flame-retardant effect of the step according to the flame-retardant time required by the step.

(1) Sampling is carried out at an inspection door below the screw extruder at intervals of 30 seconds, sampling is carried out for 3 times, and mixing is carried out uniformly. Randomly selecting 50 flakes (the area is not less than 40% of the area of the standard flakes) from the uniformly mixed flakes.

(2) Putting the sliced sheets into a baking oven at 100 +/-2 ℃ and uniformly paving the sliced sheets without overlapping for 10 minutes.

(3) In the windless show window, the alcohol lamp is ignited, one corner of the flame-retardant flaking is vertically clamped by the clamp and is placed above the alcohol lamp, and the lowest corner of the flaking is positioned in the center of the outer flame of the alcohol lamp. The burning of the flakes was observed and the time at which the flakes were ignited was recorded, as well as the after-flame time and smoldering time after the alcohol burner was removed.

The acceptable standards for the flame retardancy of the chips are shown in Table 1.

Table 1.

The flame retardance takes the flame retardant qualification rate as a judgment result:

the flame retardant yield is (number of chips that pass flame retardancy/total number of chips) × 100%.

4. Method for quickly detecting flame retardance of finished plate (flame-retardant OSB plate)

(1) Longitudinally taking 200mm wide battens at the edges of the finished boards to be inspected, respectively taking one 100mm wide wood block from the middle of the battens and two ends of the battens to obtain two 200mm multiplied by 100mm small boards, and marking;

(2) sawing the rest finished boards longitudinally from the middle, taking 200mm wide battens from the sawn positions, taking 100mm wide wood blocks from the middle of the battens and two ends of the battens respectively to obtain two 200mm multiplied by 100mm small boards, and marking;

(3)4 sample plates are respectively subjected to flame retardant effect inspection by using alcohol lamps

(4) In the windless show window, the alcohol lamp is ignited, one corner of the sample plate is vertically clamped by the clamp and is placed above the alcohol lamp, and the lowest corner of the sample plate is positioned in the center of outer flame of the alcohol lamp. The panel was observed for burning and the time to ignition was recorded, as well as the after-flame and smoldering time after the alcohol burner was removed.

(5) When the sample plate is provided with the alcohol lamp for combustion supporting, the sample plate is not ignited within 300 seconds, after the alcohol lamp is removed, the surface of each sample plate is free from open fire, the smoldering time is less than or equal to 2 seconds, and the flame retardance of the finished product plate to be inspected is judged to be qualified. And when the sample plate is unqualified in any one of the ignition time, the nameless fire time and the smoldering time, judging that the flame resistance of the finished product plate to be inspected is unqualified.

TABLE 2 Process parameters and test results of each step of EXAMPLE 2

TABLE 3 Process parameters and test results of each step in example 3

TABLE 4 Process parameters and test results of each step in example 4

TABLE 5 Process parameters and test results of each step in example 5

TABLE 6 physical Properties data for flame retardant OSB finished boards

Remarking: ") represents vertical, and" | "represents parallel.

The test method for the combustion performance of the finished oriented strand board is tested according to GB/T20284 'test for the combustion of single building materials and products' and GB/T8626 'test method for the combustibility of building materials', and is graded according to GB 8624 plus 2012 'grading for the combustion performance of building materials and products'. The finished products of examples 2-5 exhibited flame retardancy up to B₁(B-s1，d0，t1) And (4) stages.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Set up the shaving board production system that the fire retardant sprayed structure, shaving board production system includes: the device comprises a flaking device, a wet flaking conveying device I, a wet flaking bin, a wet flaking conveying device II, a drying device, a dry flaking conveying device I, a screening device, a dry flaking bin, a dry flaking conveying device II, a glue mixing device, a paving device, a hot pressing device, a post-treatment device after hot pressing and a fire retardant spraying structure;

the first flame retardant spraying structure is connected with the second wet shaving piece conveying device, the second flame retardant spraying structure is connected with the first dry shaving piece conveying device or the second dry shaving piece conveying device, the third flame retardant spraying structure is connected with the glue mixing device, and the fourth flame retardant spraying structure is connected with the paving device;

the second wet shaving conveying device is a device used in the blanking process and conveyed out by a wet shaving bin;

the second wet shaving piece conveying device comprises a blanking channel, an atomizing cylinder and a spiral extrusion conveying structure;

a spiral extrusion transmission structure is arranged below the atomizing cylinder;

the first flame retardant spraying structure is arranged in the atomizing cylinder and/or the blanking channel.

2. The production system of claim 1, wherein the post-processing device after hot pressing comprises a flame retardant spray structure.

3. The production system of claim 1 or 2, wherein the fire retardant spraying structure comprises a fire retardant storage tank, a spray head, and a fire retardant delivery conduit connecting the fire retardant storage tank and the spray head.

4. The production system of claim 1 or 2, wherein the flame retardant spraying structure comprises a flame retardant storage tank, an atomizer, and a flame retardant delivery conduit connecting the flame retardant storage tank and the atomizer.

5. The production system according to claim 2, wherein the flame retardant spraying structure in the post-treatment apparatus after hot pressing is a flame retardant spraying structure five.

6. The production system of claim 1 or 2, wherein said dry flake conveyor is disposed between said drying device and said screening device, said dry flake conveyor further comprising: the device comprises a belt, a blanking channel, a scattering device and a spiral extruder; the blanking channel is connected with the belt, and the scattering device is arranged in the blanking channel; the spiral extruder is arranged below the blanking channel.

7. The production system of claim 6, wherein the second flame retardant spraying structure is connected with the inner wall of the blanking channel and/or the scattering device.

8. The production system of claim 1 or 2, wherein the second dry flake conveyor comprises a belt, a breaker, and a blanking ramp, wherein the breaker is a breaker roll and a hollow drum; the scattering rollers are uniformly distributed above the blanking slope, and the hollow roller is arranged below the blanking slope.

9. The production system of claim 8, wherein the second fire retardant spraying structure comprises a spraying head and a fire retardant conveying pipeline, and the spraying head is arranged on the scattering roller and the hollow roller.

10. The production system of claim 1 or 2, wherein the flame retardant spraying structure three comprises a flame retardant atomizer, a flame retardant storage tank and a flame retardant conveying pipeline.

11. The production system according to claim 1 or 2, wherein the paving device is arranged between the glue mixing device and the hot-pressing device, and the paving device comprises a slab scale; and uniformly paving the slab on the slab scale.

12. The production system of claim 11, wherein the spray head of the flame retardant spraying structure four is vertically disposed above the slab.

13. The production system of claim 5, wherein the fire retardant spraying structure five comprises a travel switch one and a travel switch two.

14. The system of claim 13, wherein the fire retardant spray structure five comprises a first row of spray heads facing the front side of the sheet material and a second row of spray heads facing the back side of the sheet material.

15. A method of improving the fire retardant properties of oriented strand board in a particle board production system as claimed in any of claims 1 to 14, wherein said method comprises: in the wet shaving transfer process, the dry shaving transfer process, the glue mixing process and the post-treatment process, a flame retardant solution is sprayed to the shavings.

16. The method according to claim 15, characterized in that it comprises the steps of:

(2) after the sliced sheets obtained in the step (1) are dried, spraying a flame retardant solution to the falling dry sliced sheets in a blanking channel before the dry sliced sheets enter a dry sliced sheet storage bin, and then sequentially entering the dry sliced sheet storage bin and then entering a glue mixing device; or the like, or, alternatively,

(5) spraying a flame retardant solution on the surface of the plate blank and the belt in the paving procedure, and performing hot pressing on the plate blank after spraying to obtain a flame-retardant oriented strand board; or the like, or, alternatively,

17. The method according to claim 16, wherein in steps (1), (2), (3) and (4), the flame retardant is selected from any one, two or more of water-soluble flame retardants;

in the step (5) and the step (6), the flame retardant is selected from guanylurea phosphate and at least one of boric acid, borax and guanidine sulfamate.

18. The method of claim 16 or 17, wherein the adhesive is a polymeric isocyanate; the mass ratio of the adhesive to the flame retardant in the step (4) is 1 (0.1-3).

19. The method as claimed in claim 18, wherein the mass ratio of the adhesive to the flame retardant in step (4) is 1 (0.3-0.6).

20. The method of claim 18, wherein the mass ratio of the adhesive to the flame retardant of step (4) is 9: 4.