JP2023153103A - Flame retardant biomass product and method for producing the same - Google Patents

Abstract

To provide a biomass product that is made to be sufficiently flame retardant, a biomass product that is further rendered non-inflammable, and a method for producing the same.SOLUTION: Provided is a flame-retardant biomass product that includes a biomass, a layer impregnated with a flame retardant containing an ionic liquid on the surface of the biomass, and a top layer on the impregnated layer.SELECTED DRAWING: None

Description

The present invention relates to a flame-retardant biomass product and a method for producing the same.

Various types of retardant agents are known for making biomass noncombustible, such as a method using sodium silicate and a method using a phosphorus compound. Patent Document 1 discloses a biomass flame retardant containing an ionic liquid. As the ionic liquid, an ionic liquid having imidazolium as a cation and a halogen anion, a tetrafluoroborate anion, a hexafluorophosphate anion, a trifluoromethanesulfonyl anion, or a trifluoromethanesulfonylimide anion as anions is disclosed. Furthermore, Non-Patent Document 1 discloses an ionic liquid in which imidazolium is a cation and a phosphate ester anion is an anion.

However, although it is possible to make biomass flame retardant using the ionic liquids disclosed in Patent Document 1 and Non-Patent Document 1, the level of flame retardance is not sufficient, especially in the high temperature range around 800°C, and it is not possible to make biomass flame retardant. cannot be achieved.

Japanese Patent Application Publication No. 2013-244651

Motoi YOKOKAWA et al, Journal of the Society of Materials Science, Japan, Vol. 68, No. 9, pp. 712-717, Sep. 2019.

An object of the present invention is to provide a sufficiently flame-retardant biomass product, a flame-retardant biomass product, and a method for producing the same.

As a result of various studies on flame retardant biomass, the present inventors found that the reason why the flame retardant effect is not sufficient is that the viscosity of the flame retardant char produced when the ionic liquid melts biomass is low at high temperatures; It was found that the cause was that the fireproofing performance deteriorated due to the weight of the char peeling off and falling off from the surface to be protected, and that the above-mentioned non-combustible char could not be produced uniformly due to the effects of wood joints, etc. Then, by impregnating the surface of biomass with a flame retardant containing an ionic liquid, and then forming a top layer on the impregnated layer, the above problem can be solved, making the biomass flame retardant and even non-flammable. The present invention was completed based on the discovery that this is also possible.

That is, the present invention (1) is a flame-retardant biomass product comprising biomass, a layer impregnated with a flame retardant containing an ionic liquid on the surface of the biomass, and a top layer on the impregnated layer.

The present invention (2) is the flame-retardant biomass product according to the present invention (1), wherein the biomass is wood or wood-derived.

The present invention (3) is the flame retardant according to the present invention (1) or (2), in which the ionic liquid in the impregnation layer comprises an imidazolium cation or a cyclic amidinium cation and a phosphate anion or a phosphate ester anion. It is a biomass product.

The present invention (4) is the flame-retardant biomass product according to any one of the present inventions (1) to (3), wherein the top layer is a cured layer of a silicone resin containing an inorganic filler.

The present invention (5) is the flame-retardant biomass product according to any one of the present inventions (1) to (4), wherein the top layer includes an inorganic fiber sheet.

The present invention (6) is the flame-retardant biomass product according to any one of the present inventions (1) to (5), further comprising a heat insulating layer between the impregnated layer and the top layer.

The present invention (7) is the flame-retardant biomass product according to the present invention (6), wherein the heat insulating layer is a cured layer of an alkali metal silicate.

The present invention (8) is a step of treating the surface of biomass with a flame retardant containing an ionic liquid to form an impregnated layer, and
The method for producing a flame-retardant biomass product includes a step of applying a silicone resin composition containing an inorganic filler on the impregnated layer to form a top layer.

The present invention (9) further includes the step of forming a heat insulating layer by applying a composition containing an alkali metal silicate on the dyed layer after the step of forming the dyed layer. This is a method for producing flame-retardant biomass products.

According to the present invention, by providing a top layer with fire resistance and sufficient mechanical strength on the ionic liquid impregnated layer, the nonflammable char generated in the inflammable layer is uniformly dispersed on the biomass heat receiving surface. can be done. At the same time, the nonflammable char, whose viscosity has been reduced by receiving high-temperature heat, suppresses peeling and falling off and maintains its thickness, thereby improving fire prevention performance in a high-temperature range. As a result, the biomass product of the present invention has high flame retardancy and can also be made non-flammable. Therefore, it can be used in various applications requiring flame retardancy.

FIG. 2 is a diagram in which a cone calorimeter test was conducted on the biomass product produced in Example 1, and the heat generation rate and total calorific value were plotted against combustion time. A cone calorimeter test was conducted on the biomass product produced in Comparative Example 4, and the heat generation rate and total calorific value are plotted against combustion time.

The flame-retardant biomass product of the present invention is characterized by having a biomass, a layer impregnated with a flame retardant containing an ionic liquid on the surface of the biomass, and a top layer on the impregnated layer. Here, the ionic liquid refers to a salt of a cation and an anion that is in a liquid state at room temperature. The melting point of the ionic liquid is preferably 100°C or lower, more preferably 20°C or lower, and even more preferably -20°C or lower. Further, the freezing point is preferably 0°C or lower, more preferably -10°C or lower.

The flame-retardant biomass product of the present invention can be made not only flame-retardant but also non-combustible. The mechanism is thought to be as follows. In particular, generation of nonflammable char is important.
(1) The temperature of the wood increases due to the flame.
(2) When the temperature reaches around 200°C, hydrogen bonds in cellulose, hemicellulose, lignin, etc. in wood components are broken and decomposed due to the action of cations in the ionic liquid.
(3) Phosphoric acid contained in the anion and cellulose, etc. whose hydrogen bonds have been broken, combine to form a polymeric phosphoric acid compound, and a nonflammable char is formed on the surface of the wood.
(4) When a temperature exceeding 300° C. is reached, the cations of the ionic liquid are thermally decomposed to generate gases such as nitrogen and carbon dioxide, which exert an extinguishing effect on flames.
(5) A portion of the generated gas is absorbed into the non-combustible char, causing "foaming" in the resin, which provides an insulating effect that reduces the temperature rise of the wood.

In this specification, the flame retardant is a material that does not require a gas toxicity test as specified in the "Provision of materials that do not require a gas toxicity test (Ministry of Land, Infrastructure, Transport and Tourism Notification No. 785 of 2016)". It is preferable that the test be carried out using the 1 exothermicity test method or the 4.11.2 gas toxicity test method, and which satisfies the standards. In addition, as a flame retardant, 4.9.1 Nonflammability test is performed for materials that do not require a gas toxicity test as stipulated in the "Provision of materials that do not require a gas toxicity test (Ministry of Land, Infrastructure, Transport and Tourism Notification No. 785 of 2016)." It is preferable that the test be conducted according to the exothermic test method or 4.9.2 exothermic test method and satisfy the specifications. More specifically, the following three requirements must be satisfied for a predetermined period of time. The predetermined time is 20 minutes for the nonflammability test, 10 minutes for the quasi-nonflammability test, and 5 minutes for the flame retardancy test.
1) It must not burn. 2) It must not cause deformation, melting, cracking, or other damage that is harmful to fire safety. 3) It must not emit smoke or gas that is harmful to evacuation.

The temperature at which the furnace temperature rises from the final equilibrium temperature after heating for the predetermined period is preferably 20° C. or less, more preferably 10° C. or less.

The total calorific value in 20 minutes according to a cone calorimeter test based on ISO 5660 is preferably 8 MJ/m ² or less, more preferably 6 MJ/m ² or less, and even more preferably 5 MJ/m ² or less.

The heat generation rate is preferably 200 kw/m ² or less, more preferably 150 kw/m ² or less for a period of 10 seconds or more. Further, in a 20-minute combustion test, the number of seconds during which the heat generation rate exceeds 200 KW/m ² is preferably 3 seconds or less, more preferably 1 second or less.

[Imbued layer]
Examples of the cation include, but are not limited to, imidazolium cations, cyclic amidinium cations, pyridinium cations, and the like. Among these, imidazolium cations and cyclic amidinium cations are preferred from the viewpoint of flame retardant effect.

Examples of the imidazolium cation include 1-methylimidazolium cation, 1-ethylimidazolium cation, 1-n-propylimidazolium cation, 1,3-dimethylimidazolium cation, 1,2,3-trimethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1,2,3,4-tetramethylimidazolium cation, 1,3-diethylimidazolium cation, 1-methyl -3-n-propylimidazolium cation, 2-ethyl-1,3-dimethylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1,3-dimethyl-n-propylimidazolium cation, 1 , 3,4-trimethylimidazolium cation, 2-ethyl-1,3,4-trimethylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation , 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-methyl-3-n-octylimidazolium cation, and the like.

Examples of the cyclic amidinium cation include diazabicycloundecenium ion (a quaternary ammonium cation in which the nitrogen atom at the 1st position of 1,8-diazabicyclo[5.4.0]undec-7-ene is protonated); ), diazabicyclononenium ion (a quaternary ammonium cation in which the nitrogen atom at position 1 of 1,5-diazabicyclo[4.3.0]non-5-ene is protonated), and the like.

Examples of the pyridinium cation include pyridinium ion, 1-n-ethyl-3-methylpyridinium ion, 2-isobutylpyridinium ion, 3-isobutylpyridinium ion, 3-methylpyridinium ion, 4-methylpyridinium ion, and 2-ethylpyridinium ion. , 3-ethylpyridinium ion, 4-ethylpyridinium ion, 4-propylpyridinium ion, 2-n-hexylpyridinium ion, 3-n-hexylpyridinium ion, 3,5-dimethylpyridinium ion, 3,5-diethylpyridinium ion , 2,6-di-tert-butylpyridinium ion, 2-vinylpyridinium ion, 4-vinylpyridinium ion, 3-hydroxymethylpyridinium ion, 4-hydroxymethylpyridinium ion, 2-(2-hydroxyethyl)pyridinium ion, 2-ethenylpyridinium ion, 2-ethynylpyridinium ion, 2-methyl-5-ethylpyridinium ion, 4-ethyl-2-methylpyridinium ion, 5-butyl-2-methylpyridinium ion, 2-ethyl-6-isopropyl Pyridinium ion, 3-ethyl-4-methylpyridinium ion, 2-methyl-5-vinylpyridinium ion, 2-methyl-3-ethylpyridinium ion, 2-methyl-5-(iso)propylpyridinium ion, 2,6- Examples include bis(hydroxymethyl)pyridinium ion.

Examples of anions include, but are not limited to, phosphate anions, phosphate ester anions, borate anions, borate ester anions, and the like. Among these, phosphate anions and phosphate ester anions are preferred.

The phosphate ester anion is represented by the chemical formula (RO)PO ₃ ^2- or (RO) ₂ PO ₂ ^- . Here, R is an alkyl group, and the alkyl groups in (RO) ₂ PO ₂ ^- may be the same or different, and the number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 5. Further, (RO) ₂ PO ₂ ^- is preferable, and examples thereof include dimethyl phosphate anion, diethyl phosphate anion, and dipropyl phosphate anion.

The flame retardant for forming the impregnated layer is not particularly limited, and a solvent, various known additives, etc. can be blended therein. Examples of the solvent include water and alcohol. When dissolved in a solvent, the concentration of the ionic liquid is preferably 50 to 99% by mass, more preferably 80 to 98% by mass.

Examples of biomass include wood and easily combustible materials derived from wood. Examples of forms of biomass include wood itself, plywood, wood laminate, pulp, paper, cardboard, cloth, and fibers. Biomass can be used as it is for treatment with a biomass flame retardant, but it may also be subjected to pretreatment such as drying or Soxhlet extraction with alcohol, benzene, or the like.

The thickness of the impregnated layer depends on the biomass material used, but is preferably 0.1 to 15 mm, more preferably 1 to 10 mm, and even more preferably 2 to 10 mm. If it is less than 0.1 mm, the flame retardant effect will be small, and even if it exceeds 15 mm, no further flame retardant improvement effect will be seen, and the cost will tend to increase.

The amount of ionic liquid impregnated is preferably 1 to 70%, more preferably 10 to 60%. Here, the amount of ionic liquid impregnated can be calculated using the following formula using weight increase rate (%) (WPG: Weight Percent Gain).
WPG=(Wb-Wa)/Wax100
Wa: Weight of sample before ionic liquid treatment (g)
Wb: Weight of sample after ionic liquid treatment (g)

[Top layer]
The top layer has the functions of nonflammability, weather resistance, water resistance, and film strength, and prevents the noncombustible char from peeling off and falling off, making it uniform, and preventing the elution of ionic liquids due to rain and denaturation by ultraviolet rays. The top layer can be formed by applying a composition for forming the top layer. The composition preferably contains, for example, a curing component, an inorganic filler, a curing catalyst, an antioxidant, and the like.

Examples of the curing component include silicone resins, melamine resins, epoxy resins, and isocyanate compounds. Among these, silicone resins and isocyanate compounds are preferred. The silicone resin is preferably a mixture of a silicone resin having an aromatic group and a silicone resin not containing an aromatic group. The content of the silicone resin having an aromatic group is preferably 30 to 90% by mass, and 40 to 80% by mass in 100% by mass of the mixture of the silicone resin having an aromatic group and the silicone resin not containing an aromatic group. More preferred.

Examples of the inorganic filler include silica, alumina, titania, zirconia, silica alumina, hexagonal boron nitride, and glass powder. The shape of the inorganic filler is not limited and may be any of spherical particles, amorphous particles, and plate-like (scale-like) particles. The content of the inorganic filler is preferably 5 to 100 parts by weight, more preferably 20 to 70 parts by weight, based on 100 parts by weight of the silicone resin.

The thickness of the top layer is preferably 0.002 to 4 mm, more preferably 0.005 to 1 mm. In addition, from the viewpoint of improving transparency, the thickness is 0.02 mm or less, more preferably 0.01 mm or less. If it is less than 0.002 mm, there is a tendency that defects cannot be suppressed.

The dry weight of the top layer per unit surface area is preferably 20 g/m ² or less, more preferably 10 g/m 2 or less from the viewpoint of increasing transparency, and 2 g/m ^{2 or} more from the viewpoint of suppressing defects. It is preferable to set it as 5g/ ^m2 or more, and it is more suitable to set it as 5g/m2 or more.

[Insulating layer]
The flame-retardant biomass product of the present invention preferably has a heat insulating layer between the impregnated layer and the top layer. The heat insulating layer is a layer that has the function of preventing a rise in temperature of biomass and preventing combustible gasification. The heat insulating layer can be formed by applying a composition containing an alkali metal silicate.

The main component of the alkali metal silicate is M ₂ O.nSiO ₂ . Here, M is Na, K, Li, or a combination thereof. n is a molar ratio indicating the number of moles of SiO ₂ to the number of moles of M ₂ O, and is from 2.0 to 3.8. Further, n can preferably be set to 2.0 to 3.3. Among these, it is preferable that M is Na, that is, the main component is sodium silicate.

The concentration of M ₂ O·nSiO ₂ in the alkali metal silicate exceeds 50% by mass, and can be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more. The alkali metal silicate layer may include phosphates, borates, and the like.

Preferably, the alkali metal silicate is used as an aqueous solution. As the aqueous solution, water glass No. 1 to No. 3 specified in JIS K1408 can be suitably used. Furthermore, although n is 2.0 to 3.3 in water glasses No. 1 to 3, water glasses with n of 2.0 to 3.8 can also be suitably used.

The thickness of the heat insulating layer is preferably 0.01 to 4 mm, more preferably 0.03 to 0.9 mm, even more preferably 0.09 to 0.6 mm, and particularly preferably 0.15 to 0.45 mm. If the thickness is less than 0.01 mm, the fireproof performance will not be sufficient, and if it exceeds 4 mm, transparency and workability will tend to decrease.

The dry weight per unit area of the heat insulating layer can be 60 g/m ² or more, preferably 180 g/m ² or more, and more preferably 300 g/m ^{2 or} more from the viewpoint of imparting fireproof performance. In addition, from the viewpoint of transparency and workability, it can be set to 1800 g/m ² or less, preferably 1200 g/m ² or less, more preferably 900 g/m ² or less.

Preferably, the heat insulating layer includes an inorganic fiber sheet. The inorganic fiber sheet is a layer that has the function of imparting mechanical strength. Examples of the inorganic fibers in the inorganic fiber sheet include ceramic fibers such as glass fibers, carbon fibers, alumina fibers, and silica fibers, and metal fibers. Examples of the shape include short fibers, woven fabrics, and nonwoven fabrics. The thickness of the inorganic fiber sheet is preferably 3 to 200 μm.

The flame-retardant biomass product of the present invention is suitable for building structures such as columns, beams, floors, walls, and roofing materials, finishing materials for buildings such as ceiling materials, interior wall materials, exterior materials, stairs, and fittings, automobiles, It can be used as an interior material for railways, ships, etc., and as a material for furniture.

The method for producing a flame-retardant biomass product of the present invention includes a step of treating the surface of biomass with a flame retardant containing an ionic liquid to form an impregnated layer, and an inorganic filler on the impregnated layer. The method is characterized in that it includes a step of applying a silicone-based resin composition containing the above to form a top layer.

Examples of methods for treating with a flame retardant include coating and impregnation. The application method is not particularly limited, and a brush, roller brush, spray, etc. can be used. When the biomass is wood, the amount of ionic liquid to be treated is preferably 2 mm or more permeated from the surface, more preferably 5 mm or more.

When impregnating with a flame retardant, it can be impregnated at room temperature and pressure or under heating and reduced pressure. The heating temperature is preferably 10 to 90°C, more preferably 30 to 80°C. The pressure is preferably 0.13 kPa to normal pressure, more preferably 1 to 10 kPa. The holding time during impregnation is preferably 10 to 360 minutes, more preferably 30 to 90 minutes.

After the step of forming the dyed layer, it is preferable to include a step of applying a composition containing an alkali metal silicate on the dyed layer to form a heat insulating layer.

The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

Production example (preparation of silicone resin composition)
42% by mass of methyl phenyl low molecular weight silicone (DC3037 manufactured by Dow Toray Industries, Inc.), 26% by mass of methyl phenyl low molecular silicone (DC3074 manufactured by Dow Toray Industries, Ltd.), 26% by mass of low molecular weight methyl phenyl silicone (DC3074 manufactured by Dow Toray Industries, Ltd.) 32% by mass of SR2402) manufactured by the company was mixed and cured at 40°C for 6 hours. 100 parts by mass of titanium oxide (particle size of 5 μm or less) was dispersed and mixed with 100 parts by mass of the obtained silicone resin. Thereafter, 2 parts by mass of a curing agent (tetra-n-butoxytitanium, TBT manufactured by Nippon Soda Co., Ltd.) was mixed with 100 parts by mass of the silicone resin to prepare a silicone resin composition.

Example 1
[Imbued layer]
As the biomass, a cedar wood board (shape: 100 mm x 100 mm, thickness: 15-20 mm) was used, and as the ionic liquid, [Emim][DEP] (1-ethyl-3-methylimidazolium diethyl phosphate 100%, melting point: (approximately 20°C, freezing point: -30°C). Wood chips were immersed in [Emim] [DEP] solution in a desiccator or flask. Impregnation was carried out at a temperature of 60° C. and a pressure of 4 kPa (30 mmHg) for a holding time of 90 minutes. After a predetermined period of time had elapsed, the wood piece was taken out, dried at normal temperature and pressure for 24 hours, and its weight was measured, which was defined as the weight after ionic liquid treatment. The weight increase rate WPG at that time was 42.6%. The thickness of the impregnated layer was about 5 mm.

[Insulating layer]
After applying 1700 g/m ² of Water Glass No. 2, it was dried (at room temperature for 1 day) to form a heat insulating layer. The thickness of the heat insulating layer was 0.5 mm.

[Top layer]
A glass fiber nonwoven fabric sheet (Central Glass Fiber Surface Mat FC-30S, unit weight: 30 g/m ² , thickness: 0.13 mm) was placed on the heat insulating layer. The silicone resin composition prepared in the production example was coated at about 400 g/m ² and then dried (at room temperature for 1 day) to form a top layer. The thickness of the top layer was 0.15 mm.

Examples 2-3, Comparative Examples 1-4
Each constituent layer was formed according to Example 1 so as to have the layer structure shown in Table 1, and biomass products of each Example and Comparative Example were produced.

Example 4
[Imbued layer]
A soaked layer was formed by applying 344 g/m ² of ionic liquid [Emim] [DEP] at a concentration of 100% to the wood piece of Example 1 and allowing it to soak into the wood. The thickness of the impregnated layer was approximately 2 mm. The weight increase rate WPG was 15%. A top layer was formed on the impregnated layer in the same manner as in Example 1 to produce a biomass product.

The following evaluations were performed using the biomass products produced in each Example and Comparative Example. The results are shown in Table 1.

<Combustion test (preliminary burner test)>
The biomass products produced in Examples 1 to 4 and Comparative Examples 1 to 4 were burned from the top layer side with a burner (burner temperature 813°C) for 5 minutes, 10 minutes, and 20 minutes. The presence or absence of cracks and holes that penetrate to the back surface, which are harmful in terms of fire prevention, and the presence or absence of ignition were visually observed. In addition, the mass before and after the combustion test was measured, and the mass residual rate was calculated using the following formula.
Mass residual rate (%) = Weight after combustion / Weight before combustion × 100

Judgment of the combustion test results was made based on the following criteria.
◎: Non-combustible, with small amount of non-combustible char falling off, peeling, and cracks 〇: Non-flammable, but with non-combustible char falling off, peeling, and cracks ×: Less than semi-non-flammable

The biomass products in which the top layer was formed with the dry wood chips of Comparative Example 1 and the fiber sheet of Comparative Example 2 were burned and destroyed. In the biomass product in which only the impregnated layer of Comparative Example 3 was formed, the viscosity of the non-combustible char was low, and it peeled off and fell off from the flame contact area of the wood, making it impossible to form a uniform film-like non-combustible char, resulting in cracks, holes, etc. had suffered damage. In the biomass product of Comparative Example 4, the temperature rise and gasification in the high-temperature heat receiving part could not be suppressed, resulting in combustion and burnout.

In the biomass product with the impregnated layer and top layer formed in Example 3, the non-combustible char generated from the impregnated layer is prevented from peeling off and falling off, and a uniform film is formed on the flame contact area, improving fire protection performance. did. Furthermore, in the biomass product of Example 2 in which a top layer and a fiber sheet were provided, the film strength increased and the nonflammable char could be more reliably fixed in the flame contact area. A mass survival rate of 70% in the combustion test corresponds to the level of "non-combustibility".

In Example 4, in which the impregnated layer was applied, the flame retardant effect was confirmed, although the mass residual rate in the combustion test was somewhat lower than in Example 3, in which the impregnated layer was applied.

Examples 5-7
In Example 1, [Empy][DEP] (1-ethyl-3-methylpyridinium diethyl phosphate 100%), [EDBU][DEP] (1-ethyl-2, 3,4,6,7,8,9,10-octahydropyrimide [1,2-α]azepinium diethyl phosphate 100%), [Emim][DMP] (1-ethyl-3-methylimidazo The biomass products of Examples 5 to 7 were produced using lithium dimethyl phosphate (100%).

Using the biomass products produced in Examples 1, 5 to 7, and Comparative Example 1, the following evaluations were performed. The results are shown in Table 2.

<Combustion test (corn calorimeter test)>
A corn calorimeter test based on ISO5660 was conducted on the biomass products produced in each Example and Comparative Example. The total calorific value (MJ/m ² ) in the 20-minute test, the number of seconds during which the heat generation rate (KW/m ² ) exceeded 200, and the presence or absence of damage reaching the back surface were confirmed.

In the biomass product of Comparative Example 4, the total calorific value was 11.8 MJ/m ² and the nonflammability level was semi-nonflammable. On the other hand, the biomass product of Example 1 had a total calorific value of 5.5 MJ/m ² and was found to be nonflammable. The biomass products of Examples 5 to 7 had the same results as Example 1, and [Empy] [DEP], [EDBU] [DEP], [Emim] [DMP] had the same effect as [Emim] [DEP]. there were. The effectiveness of the ionic liquid as an impregnated layer was revealed not only from the preliminary burner test but also from the cone calorimeter test.

In addition, as the ionic liquid, 2,3,4,6,7,8,9,10-octahydropyrimide[1,2-α]azepinium phosphate, 2,3,4,6,7,8-hexane Hydropyrrolo[1,2-α]pyrimidinium phosphoric acid was used to conduct the flame retardancy evaluation described above. As a result, it was confirmed that the same results as above can be obtained no matter which ionic liquid is used.

Claims (9)

A flame-retardant biomass product comprising biomass, a layer impregnated with a flame retardant containing an ionic liquid on the surface of the biomass, and a top layer on the impregnated layer. The flame-retardant biomass product according to claim 1, wherein the biomass is wood or wood-derived. The flame-retardant biomass product according to claim 1 or 2, wherein the ionic liquid in the impregnation layer comprises an imidazolium cation or a cyclic amidinium cation, and a phosphate anion or a phosphate ester anion. The flame-retardant biomass product according to claim 1 or 2, wherein the top layer is a cured layer of silicone resin containing an inorganic filler. The flame-retardant biomass product according to claim 1 or 2, wherein the top layer includes an inorganic fiber sheet. The flame-retardant biomass product according to claim 1 or 2, further comprising a heat insulating layer between the impregnated layer and the top layer. The flame-retardant biomass product according to claim 6, wherein the heat insulating layer is a cured layer of alkali metal silicate. A step of treating the surface of biomass with a flame retardant containing an ionic liquid to form an impregnated layer, and
A method for producing a flame-retardant biomass product, comprising the step of applying a silicone resin composition containing an inorganic filler on the impregnated layer to form a top layer. The method for producing a flame-retardant biomass product according to claim 8, further comprising a step of applying a composition containing an alkali metal silicate on the impregnated layer to form a heat insulating layer after the step of forming the impregnated layer. .

Images