Polyurethane foam and articles

Abstract

To provide a method for producing polyurethane foam, which can suppress an increase in heat generation temperature during production of polyurethane foam, make scorch less likely to occur in the polyurethane foam, and can reduce the density of the polyurethane foam. [Solution] In a method for producing polyurethane foam by mixing and reacting polyurethane foam raw materials containing polyol, isocyanate, blowing agent, and catalyst, the polyurethane foam raw materials contain sodium bicarbonate and an organic solid acid such as citric acid or malic acid, and the increase in heat-generating temperature during polyurethane foam production is suppressed by the endothermic reaction between the sodium bicarbonate and the solid acid and the thermal decomposition of the sodium bicarbonate.

Description

[Technical Field]

[0001] The present invention relates to a method for producing polyurethane foam. [Background technology]

[0002] Polyurethane foams are widely used for cushioning materials such as clothing padding, furniture, bedding, and automobile seats. Polyurethane foam is produced by mixing and reacting polyurethane foam raw materials including polyol, isocyanate, blowing agent, and catalyst.

[0003] One of the characteristics of polyurethane foam is its light weight. To increase the lightness of polyurethane foam, it is necessary to increase the amount of blowing agent to produce a low-density polyurethane foam. However, if water alone is used as the blowing agent and the amount of water added is increased to produce a low-density polyurethane foam, the heat generated by the reaction (foaming reaction and resinification reaction) can reach temperatures as high as 170°C or higher. This heat can cause scorching (burning) in the polyurethane foam, resulting in a deterioration in quality. In order to suppress the occurrence of scorch due to heat generation, a method is known in which, instead of increasing the amount of water added, methylene chloride or liquefied carbon dioxide is added as a foaming aid.

[0004] However, the use of methylene chloride is restricted due to its adverse effects on the environment, etc. On the other hand, liquefied carbon dioxide gas requires dedicated equipment for supplying liquefied carbon dioxide gas at high pressure when used, which makes the production equipment complicated and increases the production costs.

[0005] One known method for suppressing the heat generation temperature is to add bicarbonate to polyurethane foam raw materials, decompose the bicarbonate using the heat generated during polyurethane foam production to produce water, and then use the latent heat of vaporization (heat of vaporization) of the water to suppress the heat generation (Patent Document 1). Because the decomposition reaction of bicarbonate is an endothermic reaction, this method also suppresses the heat generation during polyurethane foam production.

[0006] Another known method for suppressing the heat generation temperature is to add a hydrate of an inorganic compound having a decomposition temperature of 100 to 170°C to the polyurethane foam raw material, and suppress the rise in the heat generation temperature by evaporating the water produced by the decomposition of the hydrate of the inorganic compound (Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-199869 [Patent Document 2] Patent No. 4410665 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the method of adding bicarbonate to polyurethane foam raw materials, the decomposition temperature of bicarbonate is 270°C in the case of sodium bicarbonate, and decomposition of the bicarbonate does not begin until the temperature of heat generated during polyurethane foam production reaches or exceeds the decomposition temperature of the bicarbonate, so there is a risk of scorching occurring during that time.

[0009] On the other hand, when a large amount of water is added as a blowing agent to a polyurethane foam raw material, the reaction between water and isocyanate proceeds rapidly, making it difficult to control the reaction. Therefore, this method can result in poor appearance, such as the formation of flow stripes on the surface of the polyurethane foam during continuous discharge from a polyurethane foam raw material injector or cracks on the surface after curing. Furthermore, increasing the amount of inorganic compound hydrate added increases the density of the polyurethane foam. Therefore, to reduce the density of the polyurethane foam, it is necessary to increase the amount of water added as a blowing agent, which causes the reaction between water and isocyanate to proceed rapidly and increases the heat generation.

[0010] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a production method which can suppress the rise in exothermic temperature due to the mixing and reaction of polyurethane foam raw materials, thereby making it difficult for scorch to occur, and which can produce low-density polyurethane foam. [Means for solving the problem]

[0011] First aspect of the invention is a method for producing polyurethane foam by mixing and reacting polyurethane foam raw materials containing polyol, isocyanate, a blowing agent, and a catalyst, characterized in that the polyurethane foam raw materials contain sodium bicarbonate and an organic solid acid.

[0012] The second aspect of the invention is the same as the first aspect of the invention. The organic solid acid has a melting point of 40 to 190°C.

[0013] The third aspect of the invention is the first or second aspect of the invention. The organic solid acid is citric acid.

[0014] The fourth aspect of the invention is the third aspect of the invention. The amount of sodium hydrogen carbonate added is 3 to 50 times the amount of citric acid added by weight.

[0015] The fifth aspect of the invention is the third or fourth aspect of the invention. The method is characterized in that the amount of sodium hydrogen carbonate added is 0.4 to 15 parts by weight and the amount of citric acid added is 0.1 to 0.8 parts by weight relative to 100 parts by weight of the polyol.

[0016] The sixth aspect of the invention is the first or second aspect of the invention. The organic solid acid is malic acid.

[0017] The seventh aspect of the invention is the sixth aspect of the invention. The amount of sodium hydrogen carbonate added is 2 to 50 times the amount of malic acid added by weight.

[0018] The eighth aspect of the invention is the sixth or seventh aspect of the invention.The amount of sodium hydrogen carbonate added is 0.4 to 15 parts by weight, and the amount of malic acid added is 0.1 to 1.0 parts by weight, relative to 100 parts by weight of the polyol. [Effects of the Invention]

[0019] According to the production method of the present invention, the sodium bicarbonate and organic solid acid added to the polyurethane foam raw materials slowly initiate the first-stage endothermic reaction after mixing the polyurethane foam raw materials, thereby suppressing the temperature rise caused by the reaction of the polyurethane foam raw materials. If the melting point of the organic solid acid is 40 to 190°C, the first-stage endothermic reaction with sodium bicarbonate can proceed more reliably after the start of the reaction (foaming reaction or resinification reaction) during polyurethane production, thereby suppressing the heat generation temperature and reducing the deterioration of physical properties. Furthermore, an organic solid acid having the above melting point range can be pre-blended with polyurethane foam raw materials such as polyols, catalysts, foam stabilizers, and blowing agents, allowing polyurethane foam to be produced without the use of special production equipment.

[0020] The first-stage endothermic reaction when the organic solid acid is citric acid is as shown in Figure 1. The reaction between sodium bicarbonate and citric acid produces trisodium citrate, water, and carbon dioxide, and the heat absorbed during this process can suppress the temperature rise caused by the reaction of the polyurethane foam raw materials.

[0021] Furthermore, sodium bicarbonate not consumed in the first-stage endothermic reaction undergoes the second-stage endothermic reaction shown in Figure 1 due to the heat generated by the subsequent reaction of the polyurethane foam raw materials, further suppressing the temperature rise due to the reaction of the polyurethane foam raw materials. In the second-stage endothermic reaction, sodium bicarbonate not consumed in the first-stage endothermic reaction is thermally decomposed into sodium carbonate, water, and carbon dioxide.

[0022] When the organic solid acid is citric acid, the first-stage endothermic reaction involves the reaction of 3 moles of sodium bicarbonate with 1 mole of citric acid, so that the amount of sodium bicarbonate added must be at least three times that of citric acid in molar ratio to carry out the second-stage endothermic reaction. Furthermore, since the molecular weight of sodium bicarbonate is 84 and the molecular weight of citric acid is 192, the amount of sodium bicarbonate added to carry out the second-stage endothermic reaction after the first-stage endothermic reaction must be at least 1.32 times that of citric acid in weight ratio. The amount of sodium bicarbonate added is preferably 3 to 50 times, more preferably 5 to 40 times, the amount of citric acid added in weight ratio. By adjusting the amount within this range, the second-stage endothermic reaction can be carried out sufficiently.

[0023] FIG. 2 shows the first-stage endothermic reaction and the second-stage endothermic reaction when the organic solid acid is malic acid. In the first-stage endothermic reaction, two moles of sodium bicarbonate react with one mole of malic acid. Therefore, to carry out the second-stage endothermic reaction, the amount of sodium bicarbonate added must be at least twice that of malic acid, in terms of molar ratio. Furthermore, since the molecular weight of sodium bicarbonate is 84 and the molecular weight of malic acid is 134, the amount of sodium bicarbonate added to carry out the second-stage endothermic reaction after the first-stage endothermic reaction must be at least 1.26 times that of malic acid, in terms of weight ratio. The amount of sodium bicarbonate added is preferably 2 to 50 times, more preferably 2.5 to 40 times, the amount of malic acid added, in terms of weight ratio. By adjusting the amount of sodium bicarbonate to within this range, the second-stage endothermic reaction can be carried out sufficiently.

[0024] In addition, water and carbon dioxide are generated as reaction decomposition products of sodium bicarbonate and organic solid acid (e.g., citric acid or malic acid). The water generated evaporates and the carbon dioxide is naturally released from the polyurethane foam, making the polyurethane foam lighter.

[0025] Furthermore, because an organic solid acid is added as a raw material, the liquefied organic acid suppresses the rapid reaction of the polyurethane foam raw materials, thereby preventing the occurrence of poor appearance such as flow streaks when the polyurethane foam is discharged from the polyurethane foam injection machine and cracks after curing.

[0026] Furthermore, compared to the addition of sodium bicarbonate alone or inorganic compound hydrates, the addition of sodium bicarbonate and organic solid acid produces a large endothermic effect with a small amount of addition. Therefore, even with the same amount of blowing agent as in the case of the addition of sodium bicarbonate alone or inorganic compound hydrates, it is possible to reduce the density (weight) of polyurethane foam. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram showing an endothermic reaction between sodium bicarbonate and citric acid. [Figure 2] FIG. 1 is a diagram showing an endothermic reaction between sodium bicarbonate and malic acid. [Figure 3] 1 is a table showing the formulations and physical property measurement results of comparative examples. [Figure 4] 1 is a table showing the formulations and physical property measurement results of examples. DETAILED DESCRIPTION OF THE INVENTION

[0028] The polyurethane foam of the present invention is produced by mixing and reacting polyurethane foam raw materials including polyol, isocyanate, blowing agent, catalyst, sodium bicarbonate, and organic solid acid.

[0029] The polyol may be a polyol for polyurethane foam, such as polyether polyol, polyester polyol, or polyether ester polyol, and one or more of these may be used.

[0030] Examples of polyether polyols include polyether polyols obtained by adding alkylene oxides such as ethylene oxide (EO) and propylene oxide (PO) to polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose.

[0031] Examples of polyester polyols include polyester polyols obtained by polycondensation of an aliphatic carboxylic acid such as malonic acid, succinic acid, or adipic acid, or an aromatic carboxylic acid such as phthalic acid, and an aliphatic glycol such as ethylene glycol, diethylene glycol, or propylene glycol. Examples of polyetherester polyols include those obtained by reacting the above-mentioned polyether polyols with polybasic acids to form polyesters, and those having both polyether and polyester segments in one molecule.

[0032] As for the polyol, it is preferable to use one or more polyols having a hydroxyl value (OHV) of 20 to 300 mgKOH / g, a functionality of 2 to 6, and a weight average molecular weight of 500 to 15,000.

[0033] The isocyanate may be an aliphatic or aromatic polyisocyanate having two or more isocyanate groups, a mixture thereof, or a modified polyisocyanate obtained by modifying the same. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexamethane diisocyanate. Examples of aromatic polyisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate, xylylene diisocyanate, and polymeric MDI (crude MDI). Other prepolymers may also be used.

[0034] The isocyanate index (INDEX) is preferably 80 or more, more preferably 90 to 130. The isocyanate index is a value obtained by dividing the number of moles of isocyanate groups in the isocyanate by the total number of moles of active hydrogen groups such as hydroxyl groups in the polyol, and multiplying the result by 100, and is calculated as [NCO equivalent of isocyanate / active hydrogen equivalent × 100].

[0035] Water is preferred as the blowing agent. Water generates carbon dioxide gas during the reaction of polyol with isocyanate, and the carbon dioxide gas is used to foam the mixture. The amount of water used as the blowing agent is preferably 4 to 10 parts by weight per 100 parts by weight of polyol.

[0036] Known urethane catalysts can be used in combination as the catalyst. Examples include amine catalysts such as triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, and tetramethylguanidine; tin catalysts such as stannous octoate and dibutyltin dilaurate; and metal catalysts (also called organometallic catalysts) such as phenylmercury propionate and lead octenate. The catalyst may be either an amine catalyst or a metal catalyst, or both may be used in combination. The amount of the amine catalyst is preferably 0.05 to 1.0 parts by weight per 100 parts by weight of the polyol. The amount of the metal catalyst is preferably 0 or 0.05 to 0.5 parts by weight.

[0037] Sodium hydrogen carbonate is added to the polyurethane foam raw material. The amount of sodium hydrogen carbonate added is preferably in the range of 0.4 to 15 parts by weight per 100 parts by weight of polyol. By adding the amount in this range, the endothermic reaction can be carried out more efficiently.

[0038] The organic solid acid is an organic acid that is solid at room temperature (23°C). The organic solid acid is preferably an organic acid with a melting point of 40°C to 190°C, particularly a hydroxy acid or a carboxylic acid, and more preferably a melting point of 100°C to 170°C. By using an organic solid acid with a melting point within this range, the first-stage endothermic reaction with sodium bicarbonate can proceed more reliably after the start of the reaction (foaming reaction or resinification reaction) during polyurethane production, suppressing the exothermic temperature and preventing deterioration of physical properties. Furthermore, an organic solid acid with a melting point within the above range can be blended in advance with polyurethane foam raw materials such as polyol, catalyst, foam stabilizer, and blowing agent, allowing polyurethane foam to be produced without using special production equipment.

[0039] Examples of organic solid acids having a melting point of 40°C to 190°C include aliphatic hydroxy acids, aromatic hydroxy acids, polybasic carboxylic acids having a hydroxy group, and carboxylic acids. Examples of aliphatic hydroxy acids include aliphatic hydroxy acids such as glycolic acid (melting point: 75°C), malic acid (melting point: 130°C), tartaric acid (melting point: 151 to 170°C), citric acid (melting point: 153°C), quinic acid (melting point: 168°C), and shikimic acid (melting point: 185 to 187°C). Examples of aromatic hydroxy acids include salicylic acid (melting point: 159°C), orselliic acid (melting point: 175°C), mandelic acid (melting point: 119°C), benzilic acid (melting point: 150 to 152°C), and ferulic acid (melting point: 168 to 172°C).

[0040] The carboxylic acid may include saturated fatty acids, unsaturated fatty acids, aromatic carboxylic acids, and dicarboxylic acids. Examples of saturated fatty acids include 12-lauric acid (melting point: 44-46°C), myristic acid (melting point: 54.4°C), pentadecanoic acid (melting point: 51-53°C), palmitic acid (melting point: 62.9°C), margaric acid (melting point: 61°C), stearic acid (melting point: 69.9°C), behenic acid (melting point: 74-78°C), and lignoceric acid (melting point: 84.2°C).

[0041] Examples of unsaturated fatty acids include oleic acid (melting point: 134°C), sorbic acid (melting point: 135°C), and elaidic acid (melting point: 43 to 45°C). Examples of aromatic carboxylic acids include benzoic acid (melting point: 122.4°C) and cinnamic acid (melting point: 133°C), and examples of dicarboxylic acids include malonic acid (melting point: 135°C), glutaric acid (melting point: 95 to 98°C), adipic acid (melting point: 152°C), maleic acid (melting point: 131°C), and succinic acid (melting point: 185 to 187°C).

[0042] In particular, citric acid (melting point: 153° C.) and malic acid (hydroxy acid, melting point: 130° C.) are more preferred organic solid acids in the present invention. The amount of citric acid added is preferably 0.1 to 0.8 parts by weight, more preferably 0.1 to 0.6 parts by weight, relative to 100 parts by weight of polyol. By setting the amount added within this range, the endothermic reaction with sodium hydrogencarbonate can be carried out more smoothly. On the other hand, the amount of malic acid added is preferably 0.1 to 1.0 parts by weight, more preferably 0.1 to 0.8 parts by weight, and even more preferably 0.1 to 0.6 parts by weight, relative to 100 parts by weight of polyol. By adding malic acid in this range, the endothermic reaction with sodium hydrogencarbonate can be carried out more smoothly.

[0043] When citric acid is used as the organic solid acid, the amount of sodium hydrogencarbonate added is preferably 3 to 50 times, more preferably 5 to 40 times, the amount of citric acid added by weight ratio. By adding the amount in this weight ratio, the second-stage endothermic reaction can be carried out after the first-stage endothermic reaction in Figure 1. On the other hand, when malic acid is used as the organic solid acid, the amount of sodium hydrogencarbonate added is preferably 2 to 50 times, more preferably 2.5 to 40 times, the amount of malic acid added by weight ratio. By adding the amount in this weight ratio, the second endothermic reaction can be carried out after the first endothermic reaction in Figure 2.

[0044] Other auxiliary agents may be added to the polyurethane foam raw materials. Examples of auxiliary agents include foam stabilizers and colorants. As foam stabilizers, those known for polyurethane foams can be used. Examples include silicone-based foam stabilizers, fluorine-based foam stabilizers, and known surfactants. As colorants, carbon pigments and other colorants can be used depending on the intended use of the polyurethane foam.

[0045] Slab foaming is preferred for producing polyurethane foams, in which polyurethane foam raw materials are mixed and discharged onto a belt conveyor, and foamed at atmospheric pressure and room temperature. [Example]

[0046] The polyurethane foams of each Comparative Example and Example were prepared by mixing the following components in the formulations shown in Figures 3 and 4 and reacting and foaming them. The amount of each component added is expressed in parts by weight. Polyol 1: Polyether polyol, number average molecular weight: 3000, functionality: 3, hydroxyl value: 56.1 mg KOH / g, product number: GP-3000, manufactured by Sanyo Chemical Industries, Ltd. Polyol 2: Polymer polyol, functionality 3, hydroxyl value 32 mg KOH / g, product number: EL-941, manufactured by Asahi Glass Co., Ltd. Foaming agent: water Foaming aid: Methylene chloride, product number: Shin-Etsu methylene chloride, manufactured by Shin-Etsu Chemical Co., Ltd. Amine catalyst; Part Number: 33LV, manufactured by Air Products Metal catalyst: Stannous octoate, product number: MRH110, manufactured by Johoku Chemical Industry Co., Ltd. Foam stabilizer: Silicone foam stabilizer, product number: B8110, manufactured by Goldschmidt Sodium bicarbonate Citric acid Malic acid Gypsum dihydrate: Specific gravity 2.32, average particle size 40 μm, manufactured by Noritake Co., Ltd. Colorant: Carbon pigment (black pigment with 20% carbon content), product number: PC4114, manufactured by Dainippon Ink and Chemicals, Inc. Isocyanate: 2,4-TDI / 2,6-TDI = 80 / 20, Product Number: Coronate T-80, manufactured by Nippon Polyurethane Industry Co., Ltd.

[0047] During the production of polyurethane foam in each Comparative Example and Example, cream time and rise time were measured to determine reactivity. Cream time is the time it takes for the polyurethane foam raw materials to undergo a foaming reaction and for the reaction mixture to change from a liquid state at the time of mixing and discharging to a creamy, cloudy state, indicating the start of the foaming reaction. Rise time, on the other hand, is the time it takes from mixing and discharging to reaching maximum foam height. A short cream time indicates a rapid initial reaction, while a long cream time indicates a gradual initial reaction. Since rise time is the time it takes to reach maximum foam height, if the value obtained by subtracting cream time from rise time is small, it indicates a rapid reaction after the cream time; conversely, if the value obtained by subtracting cream time is large, it indicates a gradual reaction after the cream time.

[0048] In addition, the state during foaming was judged visually, and if poor foaming of down or the like occurred, the foam state was marked "x", and if foaming was good, the foam state was marked "o". Regarding the temperature during foaming, a thermocouple was set at the center of the polyurethane foam during foaming to measure the maximum heat generation temperature. If the maximum heat generation temperature was 170°C or higher, the heat generation level was rated as "high," if it was 160°C or higher but less than 170°C, the heat generation level was rated as "medium," and if it was less than 160°C, the heat generation level was rated as "low." The appearance of the polyurethane foam after foaming was visually observed, and if stripes were clearly present on the surface, it was marked "x", and if stripes were faint or absent, it was marked "o".

[0049] Furthermore, the physical properties of the polyurethane foam after foaming were measured, including density (JIS K7220), hardness (JIS K6400), tensile strength (JIS K6400), elongation (JIS K6400), and compression set (JIS K6400).

[0050] Comparative Example 1 is an example in which 100 parts by weight of Polyol 1 was used as the polyol, 6 parts by weight of water as the blowing agent, 0.4 parts by weight of an amine catalyst, 0.4 parts by weight of a metal catalyst, 1 part by weight of a foam stabilizer, 13 parts by weight of a carbon pigment as a colorant, 75.1 parts by weight of Isocyanate T-80, and an isocyanate index of 110 were used, and no sodium bicarbonate, citric acid or malic acid as an organic solid acid, or gypsum dihydrate as an inorganic compound hydrate were added. Comparative Example 1 had a cream time of 14 seconds, a rise time of 68 seconds, a foam condition of "good", a maximum heat release temperature of 182°C, a heat release level of "high", a streak condition of "good", and a density of 17.2 kg / m 3 The maximum heat generation temperature is extremely high, which causes the problem of scorching.

[0051] Comparative Example 2 is the same as Comparative Example 1 except that the metal catalyst was 0.3 parts by weight and the gypsum dihydrate was 20 parts by weight. Comparative Example 2 had a cream time of 16 seconds, a rise time of 72 seconds, a foam condition of "good", a maximum heat generation temperature of 154°C, a heat generation level of "low", a streak condition of "poor", and a density of 22.4 kg / m 3 The maximum heat generation temperature was low. However, when 20 parts by weight of gypsum dihydrate was added, clear stripes appeared, which caused problems with the appearance, and there was also the problem of high density (heavy).

[0052] Comparative Example 3 is the same as Comparative Example 1, except that 4.9 parts by weight of water was used as the blowing agent, 6 parts by weight of methylene chloride as the blowing aid, 0.35 parts by weight of the metal catalyst, and 63.3 parts by weight of Isocyanate T-80 were used. Comparative Example 3 had a cream time of 14 seconds, a rise time of 70 seconds, a foam condition of "good", a maximum heat release temperature of 158°C, a heat release level of "low", a streak condition of "good", and a density of 20.0 kg / m 3 The heat generation level and streaking were both good. However, the use of methylene chloride as a foaming aid has the problem of adversely affecting the environment.

[0053] Comparative Example 4 is the same as Comparative Example 1, except that 50 parts by weight of Polyol 1 and 50 parts by weight of Polyol 2 were used in combination as the polyols, 4.9 parts by weight of water was used as the blowing agent, 6 parts by weight of methylene chloride as the blowing aid, 0.35 parts by weight of metal catalyst, 0 part by weight of colorant, and 60.4 parts by weight of Isocyanate T-80. Comparative Example 4 had a cream time of 15 seconds, a rise time of 82 seconds, a foam condition of "good", a maximum heat release temperature of 156°C, a heat release level of "low", a streak condition of "good", and a density of 21.3 kg / m 3 The heat generation level and streaking were both good. However, the use of methylene chloride as a foaming aid has the problem of adversely affecting the environment.

[0054] Comparative Example 5 is the same as Comparative Example 1 except that 6 parts by weight of sodium bicarbonate was added. Comparative Example 5 had a cream time of 12 seconds, a rise time of 60 seconds, a foam condition of "good", a maximum heat generation temperature of 172°C, a heat generation level of "high", a streak condition of "poor", and a density of 19.3 kg / m 3 The maximum heat generation temperature was high and clear stripes were observed, resulting in a problem with the appearance.

[0055] Comparative Example 6 was the same as Comparative Example 1 except that 1 part by weight of malic acid was added. In Comparative Example 6, the cream time was 32 seconds, the rise time was 125 seconds, and the foam state was "×", meaning that foaming collapsed during foaming and no foam was obtained.

[0056] Example 1 is the same as Comparative Example 1 except that 3 parts by weight of sodium bicarbonate and 0.2 parts by weight of citric acid were added. Example 1 had a cream time of 18 seconds, a rise time of 107 seconds, a foam condition of "good", a maximum heat generation temperature of 162°C, a heat generation level of "medium", a streak condition of "good", and a density of 20.5 kg / m 3 As a result of adding both sodium bicarbonate and citric acid, the reaction was slower, the maximum heat generation temperature was lowered, and the occurrence of streaks was suppressed compared to Comparative Example 1. In addition, the density was lower (lighter) than in Comparative Example 2, in which gypsum dihydrate was added.

[0057] Example 2 is the same as Example 1 except that the amount of sodium bicarbonate added was increased to 6 parts by weight. Example 2 had a cream time of 15 seconds, a rise time of 95 seconds, a foam condition of "good", a maximum heat generation temperature of 157°C, a heat generation level of "low", a streak condition of "good", and a density of 21.0 kg / m 3 In Example 2, 0.2 parts by weight of citric acid was added and the amount of sodium hydrogen carbonate added was increased to 6 parts by weight, and as a result, the maximum heat generation temperature was able to be lowered compared to Example 1 and Comparative Example 5.

[0058] Example 3 is the same as Example 1 except that the amount of sodium bicarbonate added was increased to 10 parts by weight and the amount of citric acid was increased to 0.5 parts by weight. Example 3 had a cream time of 17 seconds, a rise time of 102 seconds, a foam condition of "good", a maximum heat generation temperature of 145°C, a heat generation level of "low", a streak condition of "good", and a density of 21.3 kg / m 3 As a result of increasing the amount of sodium hydrogen carbonate added to 10 parts by weight and the amount of citric acid to 0.5 parts by weight, the maximum exothermic temperature could be lowered compared to Examples 1 and 2.

[0059] Example 4 is the same as Example 2, except that 50 parts by weight of Polyol 1 and 50 parts by weight of Polyol 2 were used in combination as the polyols, the amount of colorant added was 0 parts by weight, and Isocyanate T-80 was 72.1 parts by weight. Example 4 had a cream time of 16 seconds, a rise time of 93 seconds, a foam condition of "good", a maximum heat release temperature of 154°C, a heat release level of "low", a streak condition of "good", and a density of 21.5 kg / m 3 The results were almost the same as those in Example 2, in which Polyol 1 was used alone as the polyol.

[0060] Example 5 is the same as Example 2, except that 0.2 parts by weight of malic acid was added instead of citric acid. Example 5 had a cream time of 17 seconds, a rise time of 98 seconds, a foam condition of "good", a maximum heat generation temperature of 160°C, a heat generation level of "medium", a streak condition of "good", and a density of 20.9 kg / m 3 As a result of adding malic acid instead of citric acid, the maximum exothermic temperature was slightly higher than in Example 2, but other aspects were similar to those of Example 2.

[0061] Example 6 is the same as Example 5, except that the foaming agents used were 5.4 parts by weight of water, 0.5 parts by weight of sodium bicarbonate, 0 parts by weight of colorant, 64.7 parts by weight of isocyanate T-80, and an isocyanate index of 105. Example 6 had a cream time of 13 seconds, a rise time of 70 seconds, a foam condition of "good", a maximum heat release temperature of 156°C, a heat release level of "low", a streak condition of "good", and a density of 21.6 kg / m 3 The results were almost the same as those in Example 5.

[0062] Example 7 is the same as Example 6 except that sodium bicarbonate was used in an amount of 1 part by weight. Example 7 had a cream time of 13 seconds, a rise time of 64 seconds, a foam condition of "good", a maximum heat generation temperature of 155°C, a heat generation level of "low", a streak condition of "good", and a density of 21.1 kg / m 3 The results were almost the same as those in Example 6.

[0063] Thus, the production method of the present invention can suppress the rise in exothermic temperature due to the mixing and reaction of polyurethane foam raw materials, making it difficult for scorch to occur, and can produce a low-density polyurethane foam.

Claims

1. An article comprising a polyurethane foam produced using a polyurethane foam raw material containing sodium bicarbonate and an organic solid acid, The article is selected from a clothing pad, bedding, an automobile seat cushion, or a non-automobile seat cushion.

2. The article described in claim 1, wherein the melting point of the organic solid acid is 40 to 190°C.

3. The article according to claim 1 or 2, wherein the density of the polyurethane foam is 21.6 kg / m 3 or less.

4. An article comprising a polyurethane foam produced using a polyurethane foam raw material containing sodium bicarbonate and an organic solid acid, the polyurethane foam containing a sodium salt of the organic solid acid and sodium carbonate, the organic solid acid having a melting point of 40°C to 190°C, The article is selected from a clothing pad, bedding, an automobile seat cushion, or a non-automobile seat cushion.

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