JP2005119038A - Semi-non-combustible woody board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semi-non-combustible woody board having both of characteristics and strength as a semi-non-combustible material by a smaller amount of a fire retardant. <P>SOLUTION: The first layer 11 becoming the surface of a woody board 10 composed of a plurality of layers is constituted of at least woody chips obtained by grinding wood, an adhesive and the fire retardant 1 and the fire retardant is added in an amount of 10-50% by weight of the whole of the first layer to ensure fire resistance/fire retardancy required as the woody board. The second layer 12 laminated on the first layer is constituted of the woody chips and the adhesive without adding the fire retardant to ensure the strength required as the woody board without being affected by the lowering of strength caused by the fire retardant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semi-incombustible wood board that is widely used for furniture, home appliances, kitchen equipment, etc., in addition to ceiling materials, wall materials, floor materials, interior materials, exterior materials for buildings.

  As wood boards that replace natural wood, wood chips such as wood flour chips and wood chip chips are used, and various wood boards that are pressure-molded by adding a binder (adhesive) as a binder are used. Specifically, a hard board, MDF, particle board, insulation board, orientation board (OSB) or the like is used.

Since such a wood board is flammable like natural wood, research to make it flame retardant has been conducted and various proposals have been made.
For example, there are mainly the following four methods for making wood itself flame-retardant.
(1) Method of immersing wood in halide solution such as salt water (2) Method of removing moisture by reducing pressure after impregnating phosphoric acid, boric acid and halogen compounds in aqueous solution (3) ) Method to mix phosphoric acid type, boric acid type, halogen type compound etc. with binder, and apply to thin plate material and paste together to make plywood (4) Method to coat fireproof paint on the surface of wood There are the following problems when trying to apply the flame retardant technique to wooden boards such as particle boards.

  In the method (1) above, dioxins may be generated during combustion, and it takes a long time to immerse. In the method (2) above, the process is complicated and pressure / decompression equipment is required. Moreover, only a limited amount can be produced in a single process, which is inefficient. In addition, in the above methods (1) and (2), the board is impregnated or immersed in the solution. Swelling occurs, causing the board to lose its original shape and reducing its strength.

  In addition, the above method (3) requires a large amount of binder and flame retardant, which not only increases the cost, but also HCHO (formaldehyde) may be generated depending on the binder. If you do, it may cause sick house syndrome.

  Furthermore, in the above method (4), the surface is coated and the wood texture is lost. In addition, in order to obtain a desired flame retardancy, a large amount of coating is required. In addition to the enormous cost, the number of processes increases, and the adhesion between the board surface and the fire-resistant paint may become a problem.

Therefore, it has been proposed that a flame retardant is premixed with a binder and a wood chip prior to hot pressing and used as a board. For example, Patent Document 1 discloses a flame retardant 1 as shown in FIG. The thickness direction distribution of the flame retardant is such that 90% by weight of the flame retardant is present in the surface layer part 2 of 5% of the total thickness from both surfaces, so that a relatively small amount of the flame retardant is added and the flame retardant is not lost. A technology for making an excellent board is disclosed.
JP-A-9-183106

  However, as a result of intensive studies on the relationship between the flame retardant necessary for securing the necessary strength and flame retardance of the wooden board, it is difficult to ensure the strength as the flame retardant is added. As shown above, when the amount of the flame retardant added to the layers other than the surface layer reaches 10% by weight, the effect on the strength increases, and in order to obtain the fire resistance as a semi-incombustible material, the surface is difficult. It has been found that it is necessary to satisfy the conflicting condition that it is highly flammable and requires the addition of a large amount of flame retardant.

  Therefore, it is not always sufficient to change the distribution in the thickness direction to a flame retardant with a single layer of wood board, and in order to ensure flame retardancy and strength with less flame retardant, fire resistance and flame resistance are required. The present invention has been completed by finding that it is effective to be composed of a plurality of layers including a layer having a strength and a layer bearing strength.

  The present invention has been made in view of the results of the above research and development, and an object of the present invention is to provide a semi-incombustible wood board having characteristics and strength as a semi-incombustible material with less flame retardant.

  In order to solve the above-mentioned problem, the semi-incombustible wood board according to claim 1 of the present invention is composed of a plurality of layers, and the first layer as a surface is composed of at least a wood chip obtained by pulverizing wood, an adhesive, and a flame retardant. In addition, the flame retardant is added in an amount of 10 to 50% by weight based on the total weight of the first layer, and the second layer laminated on the first layer is made of a wood chip without adding a flame retardant. And an adhesive.

  According to this semi-incombustible wood board, the first layer that is the surface of the wood board composed of a plurality of layers is composed of at least a wood chip obtained by pulverizing wood, an adhesive, and a flame retardant, and the flame retardant is contained in the entire first layer. By adding 10 to 50% by weight with respect to the weight, the fire resistance and flame resistance required for the wood board are secured, and the second layer laminated on the first layer is made of a wood chip without adding a flame retardant. And the adhesive are used to ensure the necessary strength as a wooden board without being affected by the strength reduction caused by the flame retardant.

  The semi-incombustible wood board according to claim 2 of the present invention has a three-layer structure in which a third layer having the same structure as the first layer is laminated on the second layer in addition to the structure according to claim 1. It is characterized by this.

  According to this semi-incombustible wood board, the third layer having the same configuration as the first layer is made into a three-layer structure in which the second layer is laminated, and even when a three-layer wood board is used. The necessary flame retardancy and strength can be secured, and a wood board without front and back surfaces can be obtained.

  Furthermore, the semi-incombustible wood board according to claim 3 of the present invention is configured by mixing a synthetic resin chip obtained by pulverizing synthetic resin with at least one of the plurality of layers in addition to the structure according to claim 1 or 2. It is characterized by this.

  According to this semi-incombustible wood board, a synthetic resin chip obtained by pulverizing a synthetic resin is mixed in at least one of the plurality of layers. For example, rigid polyurethane foam, polyisocyanurate foam, polystyrene foam, phenol foam, Chips obtained by pulverizing vinyl chloride foam, polyolefin foam, etc. can be mixed, and the synthetic resin as waste material can be reused. In particular, by using a rigid polyurethane foam chip, water resistance as a plate material can be improved.

  The semi-incombustible wood board according to claim 4 of the present invention is characterized in that, in addition to the structure according to any one of claims 1 to 3, the second layer adhesive is MDI (diphenylmethane diisocyanate). It is what.

  According to this semi-incombustible wood board, the adhesive of the second layer is MDI (diphenylmethane diisocyanate), and by using MDI as the adhesive of the second layer, the adhesiveness is excellent. The strength can be improved. In particular, the MDI and the rigid polyurethane foam chip have good adhesion, and the MDI is adsorbed on the rigid polyurethane foam chip, and further the adhesion with the wood chip is improved, so that the strength and water resistance are improved.

  Furthermore, in addition to the structure in any one of Claims 1-4, the semi-incombustible wood board of Claim 5 of this invention sets the weight ratio of each layer of the said 3 layer structure to 5: 90: 5-40: 20:40, or the weight ratio of each layer of the two-layer structure is 5:95 to 90:10.

  According to this semi-incombustible wood board, the weight ratio of each layer of the three-layer structure is 5: 90: 5 to 40:20:40, or the weight ratio of each layer of the two-layer structure is 5:95 to 90: By using the wood board as the weight ratio of each layer, the necessary flame retardancy and strength can be ensured regardless of the three-layer structure or the two-layer structure.

  Here, the quasi-incombustible material is a quasi-incombustible material according to the classification stipulated in the Building Standards Act, which satisfies non-combustibility, non-damage and non-smoke for 10 minutes after heating, and is a cone according to ISO5660 According to the calorimeter test, the total calorific value is less than 8MJ / m2 and the maximum heat generation rate exceeding 200kW / m2 does not continue for more than 10 seconds. Is.

  The wood chip means a mixture of a wood powder chip that is mainly a collection of fine powder of wood and a wood chip that is a collection of mainly fine pieces of wood, or both.

  The synthetic resin chip refers to a mixture of either or both of a resin powder chip obtained by pulverizing a synthetic resin and a resin piece chip.

  According to the semi-incombustible wood board according to claim 1 of the present invention, the first layer which is the surface of the wood board composed of a plurality of layers is composed of at least a wood chip obtained by pulverizing wood, an adhesive, and a flame retardant. Since the flame retardant is added in an amount of 10 to 50% by weight with respect to the total weight of the first layer, the fire resistance and flame resistance necessary for the wood board can be ensured. Since it is composed of a wood chip and an adhesive without adding a flame retardant, it is possible to ensure the necessary strength as a wood board without being affected by the strength reduction caused by the flame retardant.

  Thereby, the semi-incombustible wood board comprised by the multiple layer which has the characteristic and intensity | strength as a semi-incombustible material with a less flame retardant can be obtained.

  According to the quasi-incombustible wood board according to claim 2 of the present invention, the third layer having the same configuration as the first layer has a three-layer structure in which the second layer is laminated. It is possible to secure the necessary flame retardancy and strength even when making a board, and it can be made a wood board without front and back, and the front and back of the second layer is covered with the first and third layers When pressure molding is performed, it is possible to prevent adhesion to the pressure device regardless of the second layer adhesive.

  Furthermore, according to the semi-incombustible wood board according to claim 3 of the present invention, since the synthetic resin chip obtained by pulverizing the synthetic resin is mixed with at least one of the plurality of layers, the rigid polyurethane foam or the like is pulverized. By mixing the chips, the water resistance can be improved, the performance as a semi-incombustible wood board can be improved, and the synthetic resin as a waste material can be effectively used.

  Moreover, according to the quasi-incombustible wood board according to claim 4 of the present invention, the adhesive of the second layer is MDI (diphenylmethane diisocyanate), so that the adhesiveness can be improved and the strength can be further improved. Can be planned.

  Furthermore, according to the semi-incombustible wood board according to claim 5 of the present invention, the weight ratio of each layer of the three-layer structure is set to 5: 90: 5 to 40:20:40, or the weight of each layer of the two-layer structure. Since the ratio was set to 5:95 to 90:10, the flame retardancy and strength required for either a three-layer structure or a two-layer structure by using a wooden board with a weight ratio of each layer. And can be secured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view according to one embodiment when the semi-incombustible wood board of the present invention has a three-layer structure.
The semi-incombustible wood board 10 of the present invention is composed of, for example, a plurality of layers of two layers or three layers. After mixing the materials constituting each layer, it is sprayed so as to be sequentially deposited and integrated by hot pressing or the like. It is configured with a two-layer structure of a surface layer in which a flame retardant as a semi-incombustible layer is put and a core layer in which a flame retardant responsible for strength is not put, or as shown in FIG. A wooden board composed of a three-layer structure comprising a surface layer 11 into which the flame retardant 1 is placed, a core layer 12 into which no flame retardant responsible for strength is placed, and a surface layer 11 into which the flame retardant 1 as a semi-incombustible layer is placed. It is.

  In the case of a semi-incombustible wood board having a three-layer structure, the same structure as the surface layer (first layer) is usually used as the surface layer (third layer).

  The 1st layer (and 3rd layer) used as the surface which constitutes this semi-incombustible wood board is at least a wood chip which pulverized wood, an adhesive used as a binder, and a flame retardant for imparting flame retardancy. Comprising, the flame retardant is added in an amount of 10 to 50% by weight based on the total weight of the first layer.

  If the amount of the flame retardant is less than 10% by weight, the flame retardancy required as a semi-incombustible material cannot be imparted, and even if the amount exceeds 50% by weight, the flame retardancy cannot be improved and the cost increases. It is not economical.

  The wood chips constituting the surface layer include either a wood flour chip that is mainly a collection of fine powder of wood, a wood chip that is a collection of mainly fine pieces of wood, or a mixture of both. The surface layer is preferably made of finely powdered wood powder chips that are as uniform and fine as possible, and this makes it possible to obtain a board with a fine, smooth and clean surface.

  The wood flour chip, which is a collection of mainly fine powder of wood as the wood chip that constitutes the surface layer, is refined into imported wood from hardwood and conifers or domestic wood such as pine, tsuga, cedar, cypress, etc. Mainly composed of fine powder.

  Moreover, the wood chip, which is mainly a collection of small pieces of wood as a wood chip, is 0.2-3 mm in thickness and 5 mm in length of imported wood of hardwood and conifers, or domestic wood such as pine, tsuga, cedar and cypress. It is mainly composed of small pieces having a size of about 30 mm.

  The apparent specific gravity of these wood flour chips and wood chip chips when placed in a container or the like is about 0.1 to 0.2 g / cc.

  It is not preferable that the fine powder of wood and the fine pieces of wood or wood fibers are mixed, but some mixing cannot be avoided in the process of producing the wooden material, and the fine powder of wood A wood powder chip is a mixture of a small amount of wood fine pieces and wood fibers, and a wood chip is also a mixture of a small amount of wood fine powder and wood fibers mixed with wood fine pieces.

  The present invention provides performance that cannot be achieved with conventional wooden boards called semi-incombustible materials stipulated in the Building Standards Law revised in June 2002, and is used for the surface layer of these semi-incombustible wooden boards. Non-halogen or non-antimony flame retardants are used. For example, ammonium polyphosphate, ammonium phosphate, ammonium sulfate, melamine phosphate, red phosphorus, boric acid, barium metaborate, borax, sulfaming anidine, phosphorus Examples thereof include guanyl urea, guanidine phosphate, guanidine sulfate, guanidine tetraborate, aluminum hydroxide, and a mixture thereof.

  This flame retardant is used by being uniformly mixed with the wood powder chip constituting the surface layer and an adhesive serving as a binder, or by impregnating the wood powder chip with an aqueous solution of the flame retardant and then removing the moisture by drying. A wood flour chip is obtained, and this wood flour chip is used by mixing with an adhesive serving as a binder.

  Furthermore, as an adhesive used as a binder for the surface layer of this semi-incombustible wood board, an adhesive used in a wood board such as a normal particle board can be used. For example, a urea-melamine resin, a phenol resin, Examples include urea-based resins, MDI (diphenylmethane diisocyanate), TDI (tolylene diisocyanate), MDI prepolymers, TDI prepolymers, and the like.

  And the 1st layer used as the surface which constitutes this semi-incombustible wood board is at least a wood powder chip which is a wood chip which ground wood, an adhesive agent used as a binder, and a flame retardant for imparting flame retardancy After the flame retardant is added in an amount of 10 to 50% by weight based on the total weight of the first layer and mixed uniformly with the wood flour chips and the adhesive, or after the wood flour chips are impregnated with the flame retardant in advance It is mixed with an adhesive and integrally molded together with the second layer, the second layer, and the third layer by hot pressing using a normal production facility such as a particle board.

  According to the first layer as such a surface layer, it is possible to ensure the fire resistance and flame retardancy necessary as a semi-incombustible wood board.

  Next, the second core layer constituting the semi-incombustible wood board is laminated on the surface layer as the first layer, and is composed of a wood chip and an adhesive without adding a flame retardant. The main function is to bear the strength.

  The wood chip of the core layer that is the second layer can be the same as that of the surface layer, but a desired strength performance can be obtained even if the chip is coarser than the surface layer, so that the piece of wood consisting of small pieces A chip is used.

  In addition, the same adhesive as the surface layer can be used as the binder, but the adhesive strength with the wood chip can be increased by using MDI (diphenylmethane diisocyanate) in particular. The strength of the board itself, in particular, the mechanical strength and dimensional stability can be improved, and the board can be excellent in durability.

  As with the first layer as the surface layer, the second layer as the core layer is uniformly mixed with a chip chip and an adhesive, and is manufactured by using hot press molding equipment such as a normal particle board. Are integrally formed with the first layer, the first layer, and the third layer.

  According to the core layer as the second layer to which such a flame retardant is not added, by not adding the flame retardant, there is no influence of the strength reduction due to the flame retardant, and the necessary strength as a wooden board is ensured. In addition, it is possible to make all of the flame retardant used as a wooden board function for improving the flame retardancy, and the necessary flame retardance can be ensured with the minimum flame retardant.

  In such a semi-incombustible wood board having a two-layer structure of the first layer and the second layer, the weight ratio of the first layer and the second layer is preferably 5:95 to 90:10.

  In order to ensure flame retardancy, it is preferable that the weight ratio of the first layer is large, but at least the weight ratio of the first layer should be 5% by weight or more, and the strength as a board with a two-layer structure is ensured. In order to achieve this, it is preferable that the weight ratio of the second layer is large, but it is sufficient that at least the weight ratio of the second layer is 10% by weight or more.

  In the semi-incombustible wood board having a three-layer structure of the first layer, the second layer, and the third layer, the weight ratio of the first layer, the second layer, and the third layer is set to 5: 90: 5 to 40: It is preferable to configure at 20:40.

  In this case, in order to ensure flame retardancy, it is preferable that the weight ratio of the first layer is large, but it is sufficient that at least the weight ratio of the first layer is 5% by weight or more, and a board having a three-layer structure is formed. In order to ensure the strength, it is preferable that the weight ratio of the second layer is large. However, it is sufficient that at least the weight ratio of the second layer is 20% by weight or more.

  Further, in the case of a quasi-incombustible wood board having a two-layer structure or a three-layer structure, a synthetic resin chip obtained by pulverizing a synthetic resin may be mixed in each layer, for example, a mixture obtained by pulverizing a hard polyurethane waste material. By doing so, the strength and water resistance can be improved.

  As this synthetic resin chip, for example, pulverized urethane powder, which is a collection of fine powder of hard polyurethane foam, can be used, heat insulation of hard polyurethane foam collected from waste refrigerators, waste vending machines, and heat insulation generated at construction sites. It is preferable to collect scraps, residual materials, and cutting loss generated during production in a factory and finely pulverize them with a high-speed pulverizer to an average particle size of 3 mm or less. The apparent specific gravity when accumulated in a container or the like is 0.03. The thing of -0.2g / cc is preferable.

  When the synthetic resin chip has a diameter of 3 mm or more, the strength and water resistance are hardly improved, and when the surface layer is formed by mixing with the first layer or the third layer of wood flour chip, The surface smoothness of the board may be impaired.

  The synthetic resin chip is not limited to the rigid polyurethane foam, but may be other synthetic resin. In particular, by using the waste material, it is possible to effectively use the synthetic resin as the waste material.

  Such a semi-incombustible wood board can be produced using production equipment such as a conventional particle board as it is. For example, a wood chip, an adhesive and a flame retardant are mixed with a synthetic resin chip as necessary. In the case of preparing a material for a first layer and preparing a material for a second layer in which a synthetic resin chip is added and mixed with a wood chip and an adhesive as required, and a three-layer structure is used, the surface layer (the third layer ), The second layer material to be the core layer, and the first layer material to be the surface layer (first layer) are sequentially deposited (dispersed) and then integrated by thermo-pressure molding. In the same manner, a two-layer structure is also manufactured.

  In addition, mixing equipment, such as a ribbon blender, a high-speed mixer, and a tumbler, which has been used conventionally, can be used for mixing the wood chip, the adhesive, the flame retardant, and the like.

  Moreover, you may make it supply an adhesive agent, a flame retardant, etc. uniformly by a fixed amount to a wooden chip | tip with a rotary feeder, a screw feeder, etc. which were provided in the manufacturing process.

  The production of semi-incombustible wood boards using a concrete conventional binder-added wood board production line, for example, using a steel belt, depositing the material for each layer on top of it, and pressing this deposit It can be manufactured by hot pressing with a plate or a press belt, etc., but the material for each layer is pre-compressed to the desired shape before or after deposition on the molding table or steel belt. By pressure forming, the quality of the obtained semi-incombustible wood board is stabilized.

  In addition, when manufacturing a thick semi-incombustible wood board, a plurality of pre-compressed layers of material for each layer are deposited on a forming table or a steel belt and then pressure-molded to stabilize the quality.

  This pressure molding may be performed at room temperature, may be performed while steam is sprayed on the material for each layer, or may be performed by heating a molding table or a steel belt. Also good.

  In addition, in the semi-incombustible wood board of the present invention, preservatives, fungicides, insecticides, fireproofing agents, water repellents, dimensional stabilizers that can be used for conventional binder-added wood boards, such as flame retardancy and strength There is no problem if it is used as long as it does not affect the operation.

  According to such a semi-incombustible wood board, the first layer which is the surface of the wood board composed of a plurality of layers is composed of at least a wood chip obtained by pulverizing wood, an adhesive and a flame retardant, and the flame retardant is the first layer. 10 to 50% by weight is added to the total weight of the board so that the fire resistance and flame resistance required for the wood board can be secured, and a flame retardant is added to the second layer laminated on the first layer. Since it comprised with the wooden chip | tip and the adhesive agent without being, the intensity | strength required as a wooden board can be ensured, without receiving the influence of the strength reduction by a flame retardant.

  Thereby, the semi-incombustible wood board comprised by the multiple layer which has the characteristic and intensity | strength as a semi-incombustible material with the quantity of a smaller flame retardant can be obtained.

  In addition, according to this semi-incombustible wood board, the third layer having the same configuration as the first layer has a three-layer structure in which the second layer is laminated. It is possible to ensure the flame resistance and strength, and also to make a wood board without front and back surfaces, and when pressure molding is performed by covering the front and back of the second layer with the first and third layers. It is also possible to prevent adhesion to the pressure device regardless of the two-layer adhesive.

  Furthermore, according to this semi-incombustible wood board, since synthetic resin chips obtained by pulverizing synthetic resin are mixed in at least one of the plurality of layers, by mixing chips pulverized with rigid polyurethane foam or the like, water resistance In addition to improving the performance as a semi-incombustible wood board, it is also possible to reuse the synthetic resin as a waste material.

  Further, according to this semi-incombustible wood board, the adhesive of the second layer is MDI (diphenylmethane diisocyanate), so that the adhesiveness can be enhanced and the strength can be further improved.

  Further, according to this semi-incombustible wood board, the weight ratio of each layer of the three-layer structure is 5: 90: 5 to 40:20:40, or the weight ratio of each layer of the two-layer structure is 5:95 to 90: Since the weight ratio of each layer is a woody board, the necessary flame retardancy and strength can be ensured regardless of the three-layer structure or the two-layer structure.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
In this example, the following was used.
As the wood chip, an absolutely dry chip obtained from a pine generally used in particle boards was used for both the wood chip for the surface layer and the wood chip for the core layer.

  The urethane powder as the synthetic resin chip was obtained by pulverizing the waste material of the heat insulating material of the vending machine to a mean particle size of 1 mm or less with a turbo mill (manufactured by Turbo Kogyo Co., Ltd.).

As the adhesive A, urea melamine (Suibond 701, manufactured by Nippon Kasei Chemical Co., Ltd.) was used.
As the adhesive B, water-emulsified diphenylmethane diisocyanate (Wood Cure 300, manufactured by Nippon Polyurethane Industry Co., Ltd.) was used.
As the adhesive C, a phenol resin (Suisobond 166, manufactured by Nippon Kasei Chemical) was used.
As the flame retardant A, polyphosphate-ammonium (Tien S, manufactured by Taihei Chemical Industrial Co., Ltd.) having a particle size of 93% when the particle size is 100 μm or less and 7% when the particle size is 100 μm or more was used.
As the flame retardant B, melamine phosphate (MPP-A, manufactured by Sanwa Chemical Co., Ltd.) having a particle size of 10% or less is 90% and 10 μm or more is 10%.

In addition, Table 1 shows the constituent materials and blending amounts (% by weight) of the surface layer materials A to G and the core layer materials A to D used in each example and each comparative example.
The flame retardancy test was conducted by an exothermic test using a corn calorimeter tester based on ISO5660.
The bending test was performed according to JIS A5905.

(Example 1)
The surface layer material a for the first layer and the third layer is made of 100 parts by weight of a wood chip that is a wood chip, 20 parts by weight of urea urea melamine resin that is an adhesive A, and 20 parts by weight of ammonium polyphosphate that is a flame retardant A And were mixed in a high-speed mixer.
The amount of the flame retardant A added to the surface layer material a is 14.3% by weight based on the total weight of the surface layer material.

  The second layer core layer material a ′ is obtained by charging and mixing 100 parts by weight of wood chip chips, which are wood chips, and 20 parts by weight of water-emulsified diphenylmethane diisocyanate resin, which is adhesive A, into a high-speed mixer. It was.

In order to obtain a semi-incombustible wood board having a three-layer structure using the surface layer material a and the core layer material a ′, the weight ratio of the first layer: second layer: third layer is 20:60:20. Then, the surface layer material a, the core layer material a ′, and the surface layer material a are sequentially deposited (spread) on the call board, and then pre-compressed, and 12 mm distance bars ( Spacer) was placed on the mat, and hot pressing was performed for 5 minutes with a press heated at 165 ° C. on a mat to obtain a wood board with a three-layer structure of 12 mm thickness and 850 kg / m 3.
A sample of 100 mm × 100 mm square and 12 mm thickness was obtained from the obtained wood board (semi-incombustible wood board).

Using this sample, a flame retardancy test and a bending strength test were performed.
The results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 2)
The same as in Example 1 except that 20 parts by weight of melamine phosphate was used as the flame retardant B instead of 20 parts by weight of ammonium polyphosphate as the flame retardant A as the surface layer material b for the first layer and the third layer. did.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 3)
In order to make a semi-incombustible wood board having a three-layer structure, it was the same as Example 1 except that the weight ratio of the first layer: second layer: third layer was 10:80:10.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

Example 4
In order to obtain a semi-incombustible wood board having a two-layer structure, it was the same as Example 1 except that the weight ratio of the first layer to the second layer was 20:80.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is apparent from the table, even if it has two layers, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 5)
In order to obtain a semi-incombustible wood board having a three-layer structure, it was the same as Example 1 except that the weight ratio of the first layer: second layer: third layer was 30:40:30.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 6)
The surface layer material c for the first layer and the third layer was the same as that of Example 1 except that 30 parts by weight of ammonium polyphosphate as the flame retardant A was used.
The amount of the flame retardant A added to the surface layer material c is 20% by weight with respect to the total weight of the surface layer material.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 7)
The material b for the core layer in the second layer was the same as that of Example 1 except that 65 parts by weight of the wood chip was mixed with 35 parts by weight of the urethane powder.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Example 8)
The surface layer material d for the first layer and the third layer was the same as that of Example 1 except that 35 parts by weight of phenol resin as the adhesive B was used.
The amount of the flame retardant A added to the surface layer material d is 12.9% by weight with respect to the total weight of the surface layer material.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the conditions as a quasi-incombustible material were satisfied, and the bending strength was sufficient as a structural material.

(Comparative Example 1)
In order to uniformly disperse the total amount of the flame retardant A used in the surface layer material a for the first layer and the third layer in Example 1 in the first layer, the second layer, and the third layer, the flame retardant A is added to each layer. The procedure was the same as in Example 1 except that 8 parts by weight (surface layer material e and core layer material c ′) were mixed.
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the condition as a semi-incombustible material could not be satisfied, and a decrease in strength was observed.

(Comparative Example 2)
Similarly to Comparative Example 1, in order to uniformly disperse the flame retardant A in the first layer, the second layer, and the third layer, 20 parts by weight of the flame retardant A was mixed in each layer (surface material a and core layer) Except for the material d ′), it was the same as Example 1.
The molded board was weak in strength and could not be obtained, and the flame retardancy test and bending strength test were not completed.

(Comparative Example 3)
The same procedure as in Example 1 was carried out without using the flame retardant A (surface layer material f and core layer material a ′).
Using the obtained sample, a flame retardancy test and a bending strength test were performed, and the results are shown in Table 2.
As is clear from the table, the condition as a semi-incombustible material could not be satisfied.

It is sectional drawing concerning one Embodiment at the time of making the semi-incombustible wood board of this invention into a 3 layer structure. It is sectional drawing of the board excellent in the conventional flame retardance.

Explanation of symbols

1 Flame Retardant 10 Semi-incombustible wood board 11 Surface layer 12 Core layer

Claims (5)

The first layer consisting of a plurality of layers is composed of at least a wood chip obtained by pulverizing wood, an adhesive, and a flame retardant, and the flame retardant is 10 to 50 weights based on the total weight of the first layer. A semi-incombustible wood board, wherein the second layer laminated on the first layer is composed of a wood chip and an adhesive without adding a flame retardant. The semi-incombustible wood board according to claim 1, wherein the third layer has a three-layer structure in which a third layer having the same configuration as the first layer is laminated on the second layer. The semi-incombustible wood board according to claim 1 or 2, wherein a synthetic resin chip obtained by pulverizing a synthetic resin is mixed with at least one of the plurality of layers. The semi-incombustible wood board according to any one of claims 1 to 3, wherein the adhesive of the second layer is MDI (diphenylmethane diisocyanate). The weight ratio of each layer of the three-layer structure is 5: 90: 5 to 40:20:40, or the weight ratio of each layer of the two-layer structure is 5:95 to 90:10. Item 5. The semi-incombustible wood board according to any one of Items 1 to 4.

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