KR20060056546A - Flameretardant polyurethane foam and the producing method thereof - Google Patents

Abstract

The present invention relates to a foamed polyurethane having a function such as flame retardancy, heat insulation, antibacterial, deodorizing effect, and a method for manufacturing the same, and more particularly, sodium bicarbonate or ammonium phosphate for improving the flame retardancy and the generation of toxic gas in the polyester polyol Alternatively, any one of potassium bicarbonate may be mixed at a predetermined ratio, and then, ocher powder and kaolin or bentorite may be added at a predetermined ratio to increase insulation, antibacterial and deodorizing effects, and a catalyst, a stabilizer, and a blowing agent may be mixed to prepare a polyol mixture. The present invention relates to a flame-retardant expanded polyurethane and a method for producing the same, which are prepared by mixing a polyol mixture and methylene diisocyanate (MDI) in a foaming machine.

Sodium bicarbonate, ammonium phosphate, potassium bicarbonate, polyol mixtures, methylene diisocyanate (MDI)

Description

Flame retardant polyurethane foam and its manufacturing method {Flameretardant Polyurethane Foam and the producing method

The present invention relates to a foamed polyurethane having a function such as flame retardancy, heat insulation, antibacterial, deodorizing effect, and a method for manufacturing the same, and more particularly, sodium bicarbonate or ammonium phosphate for improving the flame retardancy and the generation of toxic gas in the polyester polyol Alternatively, any one of potassium bicarbonate may be mixed at a predetermined ratio, and then, ocher powder and kaolin or bentorite may be added at a predetermined ratio to increase insulation, antibacterial and deodorizing effects, and a catalyst, a stabilizer, and a blowing agent may be mixed to prepare a polyol mixture. The present invention relates to a flame-retardant expanded polyurethane and a method for producing the same, which are prepared by mixing a polyol mixture and methylene diisocyanate (MDI) in a foaming machine.

In general, foamed polyurethane is excellent in thermal insulation and easy to construct, which is widely used as insulation material for various buildings or interior materials of ships or automobiles.In order to produce foamed polyurethane, methylene diisocyanate (MDI) solution and polyester-based or When various additives such as catalyst, stabilizer and blowing agent are mixed in a polyether polyol solution and reacted in a foaming machine to react in a foaming machine, a crosslinking reaction occurs and is exothermicly resinized. Produced. The foamed polyurethane produced in this way has a high mechanical strength, good thermal insulation, adhesion, and abrasion resistance, and is manufactured from superelastic to superb hard and wear resistant according to the type of polyol used. 경도), soft, semi-hard, hard, etc. It is divided into a variety of hardness, and ultra soft or soft foam is excellent in cushioning properties (used) and is used for duvets, mattresses, etc., hard foam is rigid ( It is used as a heat insulating material for refrigerators because it has good heat insulating properties and low temperature characteristics, and the semi-foaming foam has good impact absorption ability and is used for automobile interior materials.

However, conventional foamed polyurethane molded products prepared by mixing only polyester-based or polyether-based polyol solutions with methylene diisocyanate solution as described above have a low flame retardancy and are vulnerable to fire in case of fire, and thus the foamed polyurethane molded bodies easily catch fire. Along with this, black smoke and toxic gas were generated, causing a large fire.

The present invention is to solve the above problems by mixing any one of sodium bicarbonate, ammonium phosphate or potassium bicarbonate in a polyester polyol solution in a certain ratio to improve the flame retardancy and suppress the emission of toxic gases, high insulation, adhesion, water resistance While maintaining this purpose, the purpose is to produce a foamed polyurethane reinforced with flame retardancy, antibacterial and deodorant effect.

To achieve this purpose, a mixture of sodium bicarbonate, ammonium phosphate, or potassium bicarbonate in a certain ratio is added to the polyester polyol to improve flame retardancy and suppress toxic gas generation. Kaolin or bentorite is added in a predetermined ratio, a catalyst for controlling the reaction rate, a stabilizer for controlling the density of the porous material and a blowing agent are mixed to prepare a polyol mixture, and the polyol mixture and methylene diisocyanate (MDI) are mixed in a foaming machine. It is a feature of the present invention to be prepared by reacting.

Hereinafter, the configuration of the present invention in detail.

Polyurethane foam according to the present invention is a high flame retardancy, antibacterial and deodorizing effect while maintaining high heat insulation, adhesion, water resistance, etc. First, in order to improve the flame retardancy and suppress the generation of toxic gases in polyester polyol (NaHCO ₃ ) Or ammonium phosphate (NH ₄ H ₂ PO ₄ ) or potassium bicarbonate (KHCO ₃ ) in a proportion, mixing 20 to 60 parts by weight of sodium bicarbonate or 40 to 80 parts by weight of polyester polyol or polyester polyol A primary polyol mixture is prepared by mixing 30 to 55 parts by weight of ammonium phosphate in 45 to 70 parts by weight or 15 to 55 parts by weight of potassium bicarbonate in 45 to 85 parts by weight of polyester polyol.

The sodium bicarbonate (NaHCO ₃ ) has a self-extinguishing temperature of about 270 ~ 850 ℃, potassium bicarbonate (KHCO ₃ ) has a self-extinguishing temperature of about 190 ~ 590 ℃ and ammonium phosphate (NH ₄ H ₂ PO ₄ ) is self-extinguishing It is a material that maintains a temperature of about 300 ~ 870 ℃. It is resistant to heat, has a short digestion time, and has excellent digestion ability. However, it is harmless to humans and can be easily removed after digestion. In order to add to the polyester polyol at an optimal ratio, the flame retardancy of the foamed polyurethane molded product is greatly reduced when the addition is less than the addition ratio. On the contrary, when added in excess of the addition ratio, the foamability and adhesiveness of the foamed polyurethane molded body This problem is caused to fall.

Next, 20 to 40 parts by weight of ocher powder and 10 to 30 parts by weight of kaolin or bentorite are added to the 100 parts by weight of the primary polyol mixture to increase the thermal insulation, antibacterial and deodorizing effect, and together with the primary polyol mixture as other additives. The secondary polyol mixture is prepared by adding and mixing 2 to 7 parts by weight of the catalyst, 1.5 to 2.5 parts by weight of the foaming agent, and 25 to 45 parts by weight of the blowing agent.

The ocher powder and kaolin or bentorite generally have excellent thermal insulation, antibacterial and deodorizing effects, and have properties such as constant humidity control and far-infrared radiation, and have a particle size of about 1 to 10 μm.

Tertiary amine catalysts or organic metal catalysts are generally used as the catalyst, and in the present invention, 33LV product of Wonil Urethane Co., Ltd. is used as the amine catalyst.

The foam stabilizer acts as a stabilizer for controlling the density of the porous material, thereby affecting the cell structure in the foam, and thus acts as a mixture, stability, bubble generation, bubble stability, etc. of the raw material. As the foam stabilizer, B8404 from Goldschmidt, Germany, the main ingredient of which is silicone, is used.

The blowing agent is a physical blowing agent, CFC-11, HCFC-141b, c-Pentane, etc. are used as a material that does not directly participate in the reaction and is vaporized by the heat of reaction to form bubbles. In the present invention, HCFC-141b is used.

In addition, if necessary, to the secondary polyol mixture mixed as described above, 5 to 10 parts by weight of vermiculite or pearlite and 5 to 10 parts by weight of gypsum or pearlite are added to and mixed with 100 parts by weight of the primary polyol mixture, thereby stretching the molded polyurethane foam. Strength and hardness can be increased, the vermiculite or pearlite has a particle size of 0.6 ~ 8.0 mm and gypsum is used having a particle size of about 1 ~ 10μm.

Finally, the reaction mixture of the secondary polyol mixture and the methylene diisocyanate (MDI) mixed as described above in a foaming apparatus at room temperature in a weight ratio of 1: 0.8 to 1.2 is a flame-retardant foamed polyurethane molded product within a reaction time of 2 to 7 seconds. It is produced, the foaming density of the flame-retardant foamed polyurethane molded product is able to freely control the density of 10 ~ 60kg / ㎥ by adjusting the pressure of the foamer according to the use and properties of the product.

On the other hand, in another configuration of the present invention, instead of mixing any one of sodium bicarbonate, ammonium phosphate or potassium bicarbonate for a flame retardant and toxic gas emission in a certain ratio to the polyester polyol, by mixing in a certain ratio to methylene diisocyanate (MDI) The prepared polyurethane molded article can be produced.

Detailed configuration according to this is as follows.

To 100 parts by weight of polyester polyol, 20 to 40 parts by weight of ocher powder and 10 to 30 parts by weight of kaolin or bentorite are added to increase heat insulation, antibacterial and deodorizing effect, and 100 parts by weight of polyester polyol as other additives. The polyol mixture is prepared by adding and mixing 2 to 7 parts by weight of the catalyst, 1.5 to 2.5 parts by weight of the foam stabilizer, and 25 to 45 parts by weight of the blowing agent.

Next, either sodium bicarbonate (NaHCO ₃ ), ammonium phosphate (NH ₄ H ₂ PO ₄ ), or potassium bicarbonate (KHCO ₃ ) is added to the methylene diisocyanate (MDI) to improve flame retardancy and suppress toxic gas generation. To the mixture, 20 to 60 parts by weight of sodium bicarbonate is mixed with 40 to 80 parts by weight of methylene diisocyanate (MDI), or 30 to 55 parts by weight of ammonium phosphate is mixed with 45 to 70 parts by weight of methylene diisocyanate (MDI), or methylene diisocyanate ( MDI) 45-85 parts by weight of potassium bicarbonate 15-55 parts by weight to prepare a methylene diisocyanate (MDI) mixture.

Finally, when the mixed polyol mixture and the methylene diisocyanate (MDI) mixture are mixed and reacted at room temperature in a foaming machine at a weight ratio of 1: 0.8 to 1.2, a flame-retardant foamed polyurethane molded product is formed within a reaction time of 2 to 7 seconds. The foaming density of the flame-retardant foamed polyurethane molded product can be freely adjusted to the density of 10 ~ 60kg / ㎥ by adjusting the pressure of the foamer according to the use and properties of the product.

Specific embodiments according to the present invention are as follows.

<Table 1> is the table which mix | blended the polyester polyol which concerns on this invention, sodium bicarbonate, ammonium phosphate, potassium bicarbonate in predetermined ratio, respectively.

<Table 1> Mixing ratio of primary polyol mixture

Polyester polyol                                          Sodium bicarbonate (NaHCO ₃ ) Ammonium Phosphate (NH ₄ H ₂ PO ₄ ) Potassium Bicarbonate (KHCO ₃ ) Example 1                                          60 g 40 g - -                                          Example 2                                          55 g - 45 g -                                          Example 3                                          65 g - - 35 g                                         

For 100 g of each of the primary polyol mixtures of Examples 1 to 3 mixed as shown in Table 1, 30 g of ocher, 20 g of kaolin, 5 g of an amine catalyst (33yl urethane Co., Ltd.), foam stabilizer (B8404 of Goldschmidt) 2 g and 35 g of blowing agent (HCFC-141b) were added and mixed, respectively, to prepare a secondary polyol mixture, and each of the secondary polyol mixtures and the methylene diisocyanate solution were mixed in a conventional foaming machine at a weight ratio of 1: 1 and for 6 seconds. The reaction was carried out to prepare a foamed polyurethane molded product.

<Table 2> is a table in which methylene diisocyanate, sodium bicarbonate, ammonium phosphate, and potassium bicarbonate according to another configuration of the present invention are each formulated in a predetermined ratio.

<Table 2> Mixing ratio of methylene diisocyanate mixture

Methylene diisocyanate                                          Sodium bicarbonate (NaHCO ₃ ) Ammonium Phosphate (NH ₄ H ₂ PO ₄ ) Potassium Bicarbonate (KHCO ₃ ) Example 4                                          60 g 40 g - -                                          Example 5                                          55 g - 45 g -                                          Example 6                                          65 g - - 35 g                                         

A polyol mixture comprising 30 g of yellow clay, 20 g of kaolin, 5 g of an amine catalyst (33LV) of Wonylurethane Co., Ltd. (B8404) of a foaming agent (B8404) of Goldschmidt, and 35 g of a blowing agent (HCFC-141b) with respect to 100 g of a polyester polyol; 100 g of the mixed methylene diisocyanate mixtures of Examples 4 to 6, as shown in Table 2, were mixed in a weight ratio of 1: 1 in a conventional foaming machine and reacted for 6 seconds to prepare a foamed polyurethane molded body.

<Table 3-1> and <Table 3-2> are made of the molded polyurethane foams manufactured through Examples 1 to 6, respectively, in a molded body having a width of 220 mm, a length of 220 mm, and a thickness of 50 mm, respectively. According to the repeating test for each Example three times is a table showing the results of measuring the flame retardant performance.

<Table 3-1> Flame retardant performance measurement results of Examples 1 to 3

<Table 3-2> Flame retardant performance measurement results of Examples 4 to 6

As a result of <Table 3-1> and <Table 3-2>, the flame retardant performance measurement results of the foamed polyurethane molded articles according to Examples 1 to 6 of the present invention are surface tests, additional tests, and gas-hazard test of the Korean Industrial Standard KSF 2271. All of these values exceeded the standard values, resulting in high-performance foamed polyurethane products corresponding to the second flame retardant class.

As described above, according to the present invention, sodium bicarbonate or ammonium phosphate or potassium bicarbonate, which has not been used at all, as a material for improving flame retardancy and suppressing toxic gas emission during the production of a foamed polyurethane molded product, may be selected from polyester polyol or methylene diisocyanate (MDI). By mixing it at a certain ratio, it is possible to manufacture foamed polyurethane which has high heat insulation and water resistance, but has enhanced flame retardancy, antibacterial and deodorizing effect, and also has a high degree of flame retardant grade 2 in the evaluation of flame retardant performance according to Korean Industrial Standard KSF 2271. There is an effect that can be produced of the foamed polyurethane molded product exhibiting flame retardancy.

Claims (13)

In the method for producing a foamed polyurethane prepared by mixing a polyester polyol with other additives, a catalyst, foam stabilizer and blowing agent, and methylene diisocyanate in a predetermined ratio, 40 to 80 parts by weight of the polyester polyol, 20 to 60 parts by weight of sodium bicarbonate to suppress the generation of toxic gas to prepare a primary polyol mixture, and 20 to 40 parts by weight of ocher powder and kaolin to increase the thermal insulation, antimicrobial and deodorizing effect with respect to 100 parts by weight of the primary polyol mixture Alternatively, 10 to 30 parts by weight of bentonite and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foam stabilizer, and 25 to 45 parts by weight of foaming agent are added and mixed to prepare a secondary polyol mixture, and then the secondary polyol mixture. And methylene diisocyanate (MDI) by mixing in a foaming machine in a weight ratio of 1: 0.8 to 1.2. Method of producing a flame-retardant polyurethane foam as set. In the method for producing a foamed polyurethane prepared by mixing a polyester polyol with other additives, a catalyst, foam stabilizer and blowing agent, and methylene diisocyanate in a predetermined ratio, 45 to 70 parts by weight of the polyester polyol, 30 to 55 parts by weight of ammonium phosphate for suppressing the generation of toxic gas to prepare a primary polyol mixture and 20 to 40 parts by weight of ocher powder and kaolin to increase the thermal insulation, antimicrobial and deodorizing effect with respect to 100 parts by weight of the primary polyol mixture Alternatively, the mixture of bentonite is added in an amount of 10 to 30 parts by weight and other additives to mix 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foaming agent, and 25 to 45 parts by weight of foaming agent to prepare a secondary polyol mixture, and then the secondary polyol mixture. And methylene diisocyanate (MDI) in a weight ratio of 1: 0.8 to 1.2, characterized in that prepared by mixing in the foaming machine Method of producing a flame-retardant polyurethane foam which. In the production method of the expanded polyurethane prepared by adding a catalyst, foam stabilizer and blowing agent as other additives to the polyester polyol and methylene diisocyanate in a predetermined ratio, 45 to 85 parts by weight of the polyester polyol, 15 to 55 parts by weight of potassium bicarbonate to suppress the generation of toxic gas to prepare a primary polyol mixture and 20 to 40 parts by weight of ocher powder and kaolin to increase the thermal insulation, antimicrobial and deodorizing effect with respect to 100 parts by weight of the primary polyol mixture Alternatively, 10 to 30 parts by weight of bentonite and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foam stabilizer, and 25 to 45 parts by weight of foaming agent are added and mixed to prepare a secondary polyol mixture, and then the secondary polyol mixture. And methylene diisocyanate (MDI) in a weight ratio of 1: 0.8 to 1.2, characterized in that prepared by mixing in the foaming machine Method of producing a flame-retardant polyurethane foam which. The vermiculite or pearlite according to any one of claims 1 to 3, wherein the vermiculite or pearlite having a particle size of 0.6 to 0.8 mm is used to increase the tensile strength and hardness of the foamed polyurethane molding with respect to 100 parts by weight of the primary polyol mixture. 5 to 10 parts by weight and 5 to 10 parts by weight of the gypsum having a particle size of 1 ~ 10μm addition mixing method for producing a flame-retardant foam polyurethane. In a polyurethane foam prepared by adding a catalyst, foam stabilizer, foaming agent, and methylene diisocyanate mixed with other additives to polyester polyol, bicarbonate is used to improve flame retardancy and suppress toxic gas generation at 40 to 80 parts by weight of polyester polyol. 20 to 60 parts by weight of sodium is prepared to prepare a primary polyol mixture, and 20 to 40 parts by weight of ocher powder and kaolin or bentorite are added to 100 to 100 parts by weight of the primary polyol mixture to increase heat insulation, antibacterial and deodorizing effects. As a weight part and other additives, a secondary polyol mixture was prepared by adding and mixing 2 to 7 parts by weight of a catalyst, 1.5 to 2.5 parts by weight of a foaming agent, and 25 to 45 parts by weight of a blowing agent, and then preparing the secondary polyol mixture and methylene diisocyanate (MDI). Flame retardant foam poly, characterized in that prepared by mixing in a foaming machine in a weight ratio of 1: 0.8 ~ 1.2 Urethane. In the polyurethane foam prepared by adding a catalyst, foam stabilizer and blowing agent as other additives to the polyester polyol, and methylene diisocyanate, 45 to 70 parts by weight of polyester polyol is used to improve flame retardancy and suppress toxic gas generation. Ammonium acid is mixed with 30 to 55 parts by weight to prepare a primary polyol mixture, and 20 to 40 parts by weight of ocher powder and kaolin or bentorite to enhance thermal insulation, antimicrobial and deodorizing effects with respect to 100 parts by weight of the primary polyol mixture. 30 parts by weight and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foaming agent, and 25 to 45 parts by weight of foaming agent were added and mixed to prepare a secondary polyol mixture, and then the secondary polyol mixture and methylene diisocyanate (MDI ) Is a flame-retardant foam poly, characterized in that prepared by mixing in a foaming machine in a weight ratio of 1: 0.8 ~ 1.2 Thanh. In a polyurethane foam prepared by adding a catalyst, foam stabilizer, foaming agent, and methylene diisocyanate mixed with other additives to a polyester polyol, 45 to 85 parts by weight of polyester polyol is used to improve flame retardancy and suppress toxic gas generation. 15 to 55 parts by weight of potassium is prepared to prepare a primary polyol mixture, and 20 to 40 parts by weight of ocher powder and kaolin or bentorite are added to 100 to parts by weight of the primary polyol mixture to increase the thermal insulation, antibacterial and deodorizing effects. As a weight part and other additives, a secondary polyol mixture was prepared by adding and mixing 2 to 7 parts by weight of a catalyst, 1.5 to 2.5 parts by weight of a foaming agent, and 25 to 45 parts by weight of a blowing agent, and then preparing the secondary polyol mixture and methylene diisocyanate (MDI). Flame retardant foam poly, characterized in that prepared by mixing reaction in a foaming machine in a weight ratio of 1: 0.8 ~ 1.2 Thanh. In the method for producing a foamed polyurethane prepared by mixing a polyester polyol with other additives, a catalyst, foam stabilizer, and blowing agent, and methylene diisocyanate in a predetermined ratio, the thermal insulation and antibacterial properties of 100 parts by weight of the polyester polyol and 20 to 40 parts by weight of ocher powder, 10 to 30 parts by weight of kaolin or bentorite and other additives as catalyst, 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by foaming agent, and 25 to 45 parts by weight of blowing agent are added to increase the deodorizing effect. A polyol mixture and a methylene diisocyanate mixture of 40 to 80 parts by weight of methylene diisocyanate and 20 to 60 parts by weight of sodium bicarbonate for improving flame retardancy and suppressing toxic gas generation are mixed in a foaming machine at a weight ratio of 1: 0.8 to 1.2. Method of producing a flame-retardant foam polyurethane characterized in that the production. In the method for producing a foamed polyurethane prepared by mixing a polyester polyol with other additives, a catalyst, foam stabilizer, and blowing agent, and methylene diisocyanate in a predetermined ratio, the thermal insulation and antibacterial properties of 100 parts by weight of the polyester polyol and 20 to 40 parts by weight of ocher powder, 10 to 30 parts by weight of kaolin or bentorite and other additives as catalyst, 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by foaming agent, and 25 to 45 parts by weight of blowing agent are added to increase the deodorizing effect. A polyol mixture and a methylene diisocyanate mixture of 45 to 70 parts by weight of methylene diisocyanate and 30 to 55 parts by weight of ammonium phosphate for improving flame retardancy and suppressing toxic gas generation are mixed in a foaming machine in a weight ratio of 1: 0.8 to 1.2. Method for producing a flame-retardant foam polyurethane characterized in that the reaction to produce. In the method for producing a foamed polyurethane prepared by mixing a polyester polyol with other additives, a catalyst, foam stabilizer, and blowing agent, and methylene diisocyanate in a predetermined ratio, the thermal insulation and antibacterial properties of 100 parts by weight of the polyester polyol and 20 to 40 parts by weight of ocher powder, 10 to 30 parts by weight of kaolin or bentorite and other additives as catalyst, 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by foaming agent, and 25 to 45 parts by weight of blowing agent are added to increase the deodorizing effect. A polyol mixture is mixed with 45 to 85 parts by weight of methylene diisocyanate and 15 to 55 parts by weight of potassium bicarbonate for improving flame retardancy and suppressing toxic gas generation in a foaming machine at a weight ratio of 1: 0.8 to 1.2. Method of producing a flame-retardant foam polyurethane characterized in that the production. In the polyurethane foam prepared by adding a catalyst, foam stabilizer, foaming agent, and methylene diisocyanate mixed with other additives to polyester polyol, loess for enhancing heat insulation, antibacterial and deodorizing effect with respect to 100 parts by weight of polyester polyol A polyol mixture of 20 to 40 parts by weight of powder, 10 to 30 parts by weight of kaolin or bentorite, and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foam stabilizer, and 25 to 45 parts by weight of blowing agent, and methylene Methylene diisocyanate mixture of 20 to 60 parts by weight of sodium bicarbonate for improving flame retardancy and suppressing toxic gas generation in 40 to 80 parts by weight of diisocyanate is produced by mixing and reacting in a foaming machine in a weight ratio of 1: 0.8 to 1.2. Flame retardant foamed polyurethane. In the polyurethane foam prepared by adding a catalyst, foam stabilizer, foaming agent, and methylene diisocyanate mixed with other additives to polyester polyol, ocher powder for enhancing heat insulation, antibacterial and deodorizing effect with respect to 100 parts by weight of polyester polyol Polyethylene mixture of 20 to 40 parts by weight, 10 to 30 parts by weight of kaolin or bentorite, and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foam stabilizer and 25 to 45 parts by weight of blowing agent, and methylene di 45 to 70 parts by weight of isocyanate mixed with a methylene diisocyanate mixture of 30 to 55 parts by weight of ammonium phosphate for improving flame retardancy and suppressing toxic gas generation is produced by mixing and reacting in a foaming machine in a weight ratio of 1: 0.8 to 1.2 Flame retardant foamed polyurethane. In the polyurethane foam prepared by adding a catalyst, foam stabilizer, foaming agent, and methylene diisocyanate mixed with other additives to polyester polyol, ocher powder for enhancing heat insulation, antibacterial and deodorizing effect with respect to 100 parts by weight of polyester polyol Polyethylene mixture of 20 to 40 parts by weight, 10 to 30 parts by weight of kaolin or bentorite, and 2 to 7 parts by weight of catalyst, 1.5 to 2.5 parts by weight of foam stabilizer and 25 to 45 parts by weight of blowing agent, and methylene di 45 to 85 parts of isocyanate and methylene diisocyanate mixture of 15 to 55 parts by weight of potassium bicarbonate for improving flame retardancy and suppressing toxic gas generation are prepared by mixing and reacting in a foaming machine at a weight ratio of 1: 0.8 to 1.2. Flame retardant foamed polyurethane.