Flexible polyurethane foam-forming composition and flexible polyurethane foam

Abstract

To provide a flexible polyurethane foam formable composition contributing to making of a flexible polyurethane foam which has low density, adequate softness, strong mechanical properties and durability.SOLUTION: A flexible polyurethane foam formable composition is provided, including a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a polyisocyanate component (E), wherein a ratio of a foaming reaction rate constant to a resinification reaction rate constant of the catalyst (B) is 0.090 or less, the polyisocyanate component (E) includes diphenylmethane diisocyanate (E-1) and polymethylene polyphenylene polyisocyanate (E-2) as an arbitrary component, and in the polyisocyanate component (E), a content of the diphenylmethane diisocyanate (E-1) is 75 mass% or more and 100 mass% or less, and a content of the polymethylene polyphenylene polyisocyanate (E-2) is 0 mass% or more and 25 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to a flexible polyurethane foam-forming composition and a flexible polyurethane foam. [Background technology]

[0002] Flexible polyurethane foam is widely used in cushioning materials for furniture and other applications, as well as in automobile seats, due to its excellent cushioning properties. Various characteristics are required for this flexible polyurethane foam, including foam properties, moldability, and surface curing properties.

[0003] Here, Patent Document 1 discloses a polyisocyanate composition for flexible polyurethane foam obtained by urethane-forming pure MDI (a) with an equivalent or less amount of polyol (b), and then mixing it with polymeric MDI (c), wherein the total amount of MDI components derived from (a) and (c) contains 60 to 85% by mass of 2,2'-MDI and 2,4'-MDI; the content of MDI components derived from (a) and (c) relative to the total amount of (a) and (c) is 50 to 85% by mass; and (b) is a polyether polyol having a specific number average molecular weight, a specific average number of functional groups, and a specific amount of oxyethylene groups. Furthermore, Patent Document 1 discloses that such a polyisocyanate composition for flexible polyurethane foam yields a flexible polyurethane foam with high storage stability, good moldability, and excellent mechanical properties, moist heat compression set, and rebound elasticity.

[0004] MDI is an abbreviation for diphenylmethane diisocyanate (hereinafter referred to as MDI), polymeric MDI is an abbreviation for polymethylene polyphenylene polyisocyanate (hereinafter referred to as p-MDI), and pure MDI is a general term for 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2008 / 136179 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in the composition described in Patent Document 1, the isocyanate component is modified with a polyol, resulting in high viscosity and low NCO content. Therefore, it was extremely difficult to obtain a soft polyurethane foam with low density and excellent elasticity. Furthermore, when producing urethane foam, carbon dioxide is generated by reacting the NCO group of the isocyanate with water to cause foaming. However, adding a large amount of water to reduce density leads to the formation of many highly cohesive urea bonds, resulting in the foam becoming too hard.

[0007] Therefore, one aspect of this disclosure is directed toward providing a flexible polyurethane foam-forming composition that contributes to the production of a flexible polyurethane foam having low density, moderate softness, strong mechanical properties, and durability. Another aspect of this disclosure is directed toward providing a flexible polyurethane foam having low density, moderate softness, strong mechanical properties, and durability. [Means for solving the problem]

[0008] Each aspect of this disclosure provides the following (1) to (6): (1) Polyol component (A), Catalyst (B), Foam stabilizer (C), Foaming agent (D), It contains polyisocyanate component (E), The ratio of the foaming reaction rate constant to the resinification reaction rate constant of catalyst (B) (foaming reaction rate constant / resinification reaction rate constant) is 0.090 or less. The aforementioned polyisocyanate component (E) is Diphenylmethane diisocyanate (E-1) and, It contains the optional component polymethylene polyphenylene polyisocyanate (E-2), In the aforementioned polyisocyanate component (E), The content of the diphenylmethane diisocyanate (E-1) is 75% by mass or more and 100% by mass or less, relative to the total amount of the polyisocyanate component (E). A flexible polyurethane foam-forming composition wherein the content of the polymethylene polyphenylene polyisocyanate (E-2) is 0% by mass or more and 25% by mass or less, relative to the total amount of the polyisocyanate component (E).

[0009] (2) The flexible polyurethane foam-forming composition according to (1), wherein the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the diphenylmethane diisocyanate (E-1) is 20% by mass or more and 60% by mass or less based on the total amount of the diphenylmethane diisocyanate (E-1).

[0010] (3) The flexible polyurethane foam forming composition according to (1) above, wherein the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the diphenylmethane diisocyanate (E-1) is 30% by mass or more and 50% by mass or less based on the total amount of the diphenylmethane diisocyanate (E-1).

[0011] (4) A flexible polyurethane foam, which is a foamed molded article of a flexible polyurethane foam-forming composition described in any one of items (1) to (3) above.

[0012] (5) Apparent density of 25 kg / m³ 3 More than 40kg / m 3 The following: The 25% compression hardness of the skinned foam test specimen, measured according to Method B described in JIS K6400, was 100 N / 314 cm. 2The flexible polyurethane foam described in the above (4) is as follows.

[0013] (6) The elongation rate measured according to the method described in JIS K6400 is 100% or more, the tear strength is 4.5 N / cm or more, and the wet heat compression strain is 25% or less. The flexible polyurethane foam described in the above (4) or (5). [Effect of the Invention]

[0014] According to one aspect of the present disclosure, it is possible to provide a flexible polyurethane foam-forming composition that contributes to the production of a flexible polyurethane foam having a low density, appropriate softness, strong mechanical properties, and durability. Further, according to one aspect of the present disclosure, it is possible to provide a flexible polyurethane foam having a low density, appropriate softness, strong mechanical properties, and durability. [Embodiments for Carrying Out the Invention]

[0015] Hereinafter, exemplary embodiments for carrying out each aspect of the present disclosure will be described in detail. [Flexible Polyurethane Foam-Forming Composition] The flexible polyurethane foam-forming composition according to one aspect of the present disclosure comprises a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a polyisocyanate component (E). The ratio of the foaming reaction rate constant to the resinification reaction rate constant of the catalyst (B) (foaming reaction rate constant / resinification reaction rate constant) is 0.090 or less. The polyisocyanate component (E) comprises diphenylmethane diisocyanate (E-1), and, optionally, polymethylene polyphenylene polyisocyanate (E-2), and in the polyisocyanate component (E), The content of the diphenylmethane diisocyanate (E-1) is 75% by mass or more and 100% by mass or less, relative to the total amount of the polyisocyanate component (E). The content of the aforementioned polymethylene polyphenylene polyisocyanate (E-2) is 0% by mass or more and 25% by mass or less, relative to the total amount of the polyisocyanate component (E).

[0016] <<Polyol component (A)>> The polyol component (A) undergoes polyaddition with the polyisocyanate component (E) to form polyurethane. Preferably, the polyol component (A) is at least one selected from the group consisting of polyether polyols and polyester polyols. The number-average molecular weight of the polyol component (A) is preferably between 1,000 and 10,000. A number-average molecular weight of 1,000 or more results in even greater flexibility of the resulting foam. A number-average molecular weight of 10,000 or less results in even greater hardness of the foam. The nominal number of functional groups in polyol component (A) is preferably 2 or more. A nominal number of functional groups of 2 or more further improves the moist heat compressive strain, which is an indicator of durability. The nominal number of functional groups refers to the theoretical average number of functional groups (number of active hydrogen atoms per molecule) assuming no side reactions occur during the polymerization reaction of the polyol.

[0017] Examples of polyether polyols include polypropylene ether polyol, polyethylene polypropylene ether polyol (hereinafter referred to as PPG), and polytetramethylene ether glycol (hereinafter referred to as PTG). Examples of polyester polyols include polycondensation type polyester polyols consisting of adipic acid and a diol, and lactone-based polyester polyols such as polycaprolactone polyol.

[0018] From the viewpoint of improving the durability of the resulting foam, it is preferable that the polyol component (A) contains a polyoxyalkylene polyol (A-1) having a total unsaturation degree of 0.001 meq. / g or more and 0.04 meq. / g or less. A higher total unsaturation degree of polyol (A-1) means that there are more monool components, etc., that have unsaturated groups at the terminals. Therefore, if the total unsaturation degree of polyoxyalkylene polyol (A-1) is 0.04 meq. / g or less, the crosslinking density of the resulting foam becomes higher, and the durability is further improved. In addition, if the total unsaturation degree of polyoxyalkylene polyol (A-1) is 0.001 meq. / g or more, the manufacturing time can be shortened and productivity can be improved, making it economical. For polyoxyalkylene polyol (A-1), it is preferable that the polymerization catalyst is at least one selected from a complex metal cyanide catalyst, a phosphazene catalyst, and an imino group-containing phosphazenium salt.

[0019] The polyol component (A) preferably includes a polyether polyol (A-2) having a polyoxyalkylene chain made of a copolymer of oxyethylene and oxypropylene, as this promotes the breaking of bubbles in the flexible polyurethane foam. The polyether polyol (A-2) preferably has a nominal number of 2 to 4 functional groups.

[0020] The oxyethylene units in polyether polyol (A-2) are preferably 60% to 90% by mass, and more preferably 60% to 80% by mass. Having 60% to 90% by mass of oxyethylene units further improves durability. Furthermore, from the viewpoint of storage stability at low temperatures, it is preferable that the copolymer of oxyethylene and oxypropylene in polyether polyol (A-2) is a random copolymer.

[0021] The content of polyether polyol (A-2) is preferably 0.5% by mass or more and 5.0% by mass or less relative to the polyol component (A). If it is 0.5% by mass or more, the moldability of the foam is further improved. If it is 5.0% by mass or less, the elongation of the resulting foam is further improved.

[0022] For the polyol component (A), it is preferable to use a polymer polyol obtained by polymerizing vinyl monomers in a polyol using a conventional method for the purpose of adjusting hardness. Examples of such polymer polyols include those obtained by polymerizing vinyl monomers in a polyalkylene polyol such as PPG in the presence of a radical initiator and stably dispersing them. Examples of vinyl monomers include acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl methacrylate, and alkyl methacrylate, with acrylonitrile and styrene being preferred. Examples of such polymer polyols include EL-910 and EL-923 from AGC Corporation, and FA-728R from Sanyo Chemical Industries Ltd.

[0023] <<Catalyst (B)>> Examples of catalyst (B) include various urethane catalysts known in the field. For example, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, bis-(2-dimethylaminoethyl) ether, triethylenediamine, 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,2-dimethylimidazole, dimethylethanolamine, N,N-diethylethanolamine, N,N-dimethyl-N-hexanolamine, and their organic salts; organometallic compounds such as stanus octoate and zinc naphthenate; etc. These may be a single type or a combination of two or more types.

[0024] The content of catalyst (B) is preferably 0.01% by mass or more and 10% by mass or less relative to the polyol component (A). If it is 0.01% by mass or more, curing deficiency can be further suppressed, and if it is 10% by mass or less, moldability is further improved.

[0025] The ratio of the foaming reaction rate constant to the resinification reaction rate constant of catalyst (B) (foaming reaction rate constant / resinification reaction rate constant) is 0.090 or less, preferably 0.005 to 0.080, and more preferably 0.010 to 0.080. The resin formation reaction rate constant is the reaction rate constant used when an isocyanate group and a hydroxyl group react to form a urethane bond. Furthermore, the foaming reaction rate constant is the reaction rate constant for the formation of a urea bond through the reaction of an isocyanate group with water. The inventors speculate that when the ratio of the foaming reaction rate constant to the resin formation reaction rate constant (foaming reaction rate constant / resin formation reaction rate constant) is 0.090 or less, the formation of urethane bonds is promoted, and the molecular weight increase proceeds sufficiently, thereby suppressing the deterioration of moldability.

[0026] The resin formation reaction rate constant (k1w) is a parameter calculated by the following method. Specifically, toluene diisocyanate and diethylene glycol are charged so that the [isocyanate group] / [hydroxyl group] (molar ratio) is 1.0, a fixed amount of catalyst component (the target for calculating k1w) is added, the reaction is carried out in a benzene solvent at a constant temperature, and the amount of unreacted isocyanate is measured. Here, assuming that the reaction between toluene diisocyanate and diethylene glycol is first-order at each concentration, the following equation holds. dx / dt = k(ax) 2 (1) x: Concentration of the reacted NCO group (mol / L) a: Initial concentration of NCO group (mol / L) k: reaction rate constant (L / mol·h) t: reaction time (h)

[0027] Substituting the initial conditions t=0 and X=0 into equation (1) and integrating, we obtain the following equation. 1 / (ax) = kt + 1 / a (2) k = ko + KcC (3) ko: Reaction rate constant without catalyst (L / mol·h) Kc: Catalytic constant (L 2 (g·mol·h) C: Catalyst concentration in the reaction system (mol / L)

[0028] The reaction rate constant k is determined from equation (2), and the catalyst constant Kc is determined by substituting it into equation (3). Dividing the calculated catalyst constant Kc by the molecular weight (mc) of the catalyst gives the resin formation reaction rate constant k1w(L), which can be considered as the activity per unit mass. 2 Calculate (g·mol·h) Kc / mc=k1w (4) Furthermore, if catalyst (B) is a combination of n types (n≧2), the resin formation reaction rate constant k1w(L 2 The value of (g·mol·h) can be calculated using equation (5).

[0029]

number

[0030] W: Mass of catalyst (g)

[0031] On the other hand, the foaming reaction constant (k2w) can be determined in the same manner as above by reacting toluene disisocyanate with water in a benzene solvent under the same conditions as the resin formation reaction described above.

[0032] <<Foam stabilizer (C)>> As the foam stabilizer (C), a conventional surfactant is used, and organosilicon-based surfactants are preferably used. Examples include SZ-1327, SZ-1325, SZ-1336, and SZ-3601 from Toray Dow Corning, Y-10366 and L-5309 from Momentive, and B-8724LF2 and B-8715LF2 from Evonik. The content of the foam stabilizer (C) is preferably 0.1% by mass or more and 3.0% by mass or less relative to the polyol component (A).

[0033] <<Foaming agent (D)>> Water is preferred as the foaming agent (D). Water reacts with isocyanate groups to form high-hardness urea groups and generates carbon dioxide. The carbon dioxide causes foaming in the flexible polyurethane foam-forming composition, thus forming urethane foam.

[0034] The solution may contain other foaming agents along with water. Examples of other foaming agents include small amounts of low-boiling point organic compounds such as cyclopentane or isopentane. Alternatively, foaming may be induced by mixing and dissolving air, nitrogen gas, liquefied carbon dioxide, etc., into the stock solution using a gas loading device.

[0035] The content of the foaming agent (D) is preferably 0.5% by mass or more and 10% by mass or less relative to the polyol component (A). Apparent density: 40 kg / m³ 3 When obtaining a low-density flexible polyurethane foam of less than 1 / 2, the density is preferably 3.0% by mass or more and 7.0% by mass or less, and more preferably 3.0% by mass or more and 5.5% by mass or less. If the density exceeds the upper limit, foaming may become unstable, and if it is below the lower limit, the density of the foam may not be sufficiently reduced.

[0036] <<Polyisocyanate component (E)>> The polyisocyanate component (E) is, Diphenylmethane diisocyanate (E-1) and, It contains the optional component polymethylene polyphenylene polyisocyanate (E-2), In the polyisocyanate component (E), The content of diphenylmethane diisocyanate (E-1) is 75% by mass or more and 100% by mass or less, relative to the total amount of the polyisocyanate component (E). The content of polymethylene polyphenylene polyisocyanate (E-2) is 0% by mass or more and 25% by mass or less, relative to the total amount of the polyisocyanate component (E).

[0037] Examples of the polyisocyanate component (E) include 4,4'-diphenylmethane diisocyanate (hereinafter referred to as 4,4'-MDI), 2,4'-diphenylmethane diisocyanate (hereinafter referred to as 2,4'-MDI), 2,2'-diphenylmethane diisocyanate (hereinafter referred to as 2,2'-MDI), and other diphenylmethane diisocyanates (hereinafter referred to as MDI), as well as polymethylene polyphenylene polyisocyanate (hereinafter referred to as p-MDI); and various modified compounds using these as isocyanate sources. These may be used individually or in combination of two or more types. Examples of modified compounds include urethane modified compounds, urea modified compounds, allophanate modified compounds, nurate modified compounds, biuret modified compounds, and the like.

[0038] The MDI (E-1) content of the polyisocyanate component (E) is between 75% by mass and 100% by mass. If the MDI content is less than 75% by mass, the elongation of the flexible polyurethane foam decreases as the crosslinking density increases, and sufficient foam strength cannot be obtained.

[0039] Furthermore, the total content of 2,2'-MDI and 2,4'-MDI in MDI(E-1) (hereinafter referred to as the isomer content) is preferably 20% by mass or more and 60% by mass or less, and more preferably 30% by mass or more and 50% by mass or less, relative to the total amount of MDI(E-1). When it is 60% by mass or less, the reactivity is further improved, the molding cycle can be further shortened, and the occurrence of problems such as shrinkage after molding can be further reduced by further suppressing an increase in the closed-cell ratio of the foam.

[0040] <<Molar ratio (NCO group / active hydrogen group)>> In the soft polyisocyanate-forming composition, the molar ratio (NCO groups / active hydrogen groups) of all isocyanate groups to all active hydrogen groups in the active hydrogen group-containing compound containing water is preferably 0.5 or more and 1.4 or less (isocyanate index (NCO INDEX) = 50 to 140), and more preferably 0.7 or more and 1.2 or less (NCO INDEX = 70 to 120). Within this range, the durability and molding cycle of the resulting foam are good. If the NCO INDEX is 50 or more, the durability is further improved, and the tendency for the foaming property to increase excessively can be suppressed. If the NCO INDEX is 140 or less, the molecular weight increase proceeds rapidly, and foam collapse during foam foaming is more highly suppressed.

[0041] <<Other components>> The soft polyurethane foam-forming composition may contain various known additives and auxiliaries such as fillers like calcium carbonate and barium sulfate, flame retardants, plasticizers, colorants, and antifungal agents as necessary.

[0042] <Soft polyurethane foam, its manufacturing method> The soft polyurethane foam according to one aspect of the present disclosure is a foamed molded body of the above-described soft polyurethane foam-forming composition. This soft polyurethane foam has good riding comfort when used as, for example, a cushioning material. The apparent density of the soft polyurethane foam is preferably 25 kg / m 3 or more and 40 kg / m 3 or less. The skin-covered foam test piece of the soft polyurethane foam (details will be described later) preferably has a 25% compression hardness of 100 N / 314 cm 2 or less. The elongation rate of the soft polyurethane foam is preferably 100% or more. The tear strength of the soft polyurethane foam is preferably 4.5 N / cm or more. The wet heat compression strain of the soft polyurethane foam is preferably less than 25%.

[0043] Next, we will explain the manufacturing method of flexible polyurethane foam. A method for manufacturing flexible polyurethane foam according to one aspect of this disclosure is: The process involves mixing a polyol component (A), a catalyst (B), a foam stabilizer (C), a blowing agent (D), and a polyisocyanate component (E) to obtain a mixed solution. The method comprises reacting and foaming the mixture to obtain a flexible polyurethane foam.

[0044] Here, each component (A) to (E) may be added one by one in sequence, or two or more may be mixed beforehand and then all components may be mixed together at the end. In the former case, there are no restrictions on the order in which components (A) to (E) are added; any order is acceptable. Furthermore, two or more components from (A) to (E) may be added separately or simultaneously. In the latter case, for example, The first liquid is obtained by the first pre-mixing, The second liquid is obtained through a second pre-mixing, The method includes mixing the first liquid and the second liquid to obtain a mixed solution. Here, for example, the first liquid may contain a polyol component (A), a catalyst (B), a foam stabilizer (C), and a blowing agent (D), while the second liquid may consist only of an isocyanate component (E). In this case, the second pre-mixing can be omitted.

[0045] It is preferable to inject the mixed liquid (foaming concentrate) into the mold, and then allow it to react, foam, and harden. The mold temperature when injecting the above mixture into the mold is usually 30°C to 80°C, preferably 45°C to 65°C. If the mold temperature when injecting the above mixture into the mold is 30°C or higher, the reaction rate is improved and the production cycle can be shortened. If the mold temperature is 80°C or lower, the reaction between water and isocyanate is further suppressed in relation to the reaction between polyol and isocyanate, thereby further suppressing the collapse of the foam during foaming.

[0046] When the above foaming stock is foamed and hardened, the hardening time is preferably 10 minutes or less, and more preferably 7 minutes or less, considering the production cycle of a typical flexible mold foam.

[0047] When manufacturing flexible molded foam, the above components can be mixed using a high-pressure foaming machine or a low-pressure foaming machine, as is the case with ordinary flexible molded foam.

[0048] It is preferable to mix the isocyanate component (E) and the polyol component (A) immediately before foaming. Components (B) to (D) and other components can be pre-mixed with the isocyanate component (E) or polyol component (A) to the extent that they do not affect the storage stability or reactivity of the raw materials over time. The resulting mixture may be used immediately after mixing, or it may be stored and used as needed. In the case of a foaming apparatus that can simultaneously introduce more than two components into the mixing section, each component (A) to (E), and additives, etc., can also be introduced into the mixing section individually.

[0049] Furthermore, the mixing method may be either dynamic mixing, which is performed in the mixing chamber of the foaming machine's machine head, or static mixing, which is performed in the liquid delivery piping, or both may be used in combination. Mixing of gaseous components such as physical foaming agents and liquid components is often performed by static mixing, and mixing of components that can be stably stored as liquids is often performed by dynamic mixing, but this is not limited to these methods. As a foaming apparatus that can be used in the manufacture of flexible polyurethane foam, a high-pressure foaming apparatus that does not require solvent cleaning of the mixing section is preferred.

[0050] The mixture obtained by this mixing process is discharged into a mold, reacted, foamed, and hardened, and then demolded. To facilitate the demolding process, it is preferable to apply a release agent to the mold beforehand. Examples of release agents used include those commonly used in the molding industry.

[0051] Although the demolded product can be used as is, it is preferable to break the cell membrane of the foam under compression or reduced pressure using conventionally known methods to stabilize the product's appearance and dimensions thereafter.

[0052] By the method for manufacturing the flexible polyurethane foam described above, Apparent density: 25 kg / m³ 3 More than 40kg / m 3 below, The 25% compression hardness of the skinned foam test specimen was 100 N / 314 cm. 2 below, Tear strength of 4.5 N / cm or more, Moist heat compressive strain is less than 25%, A flexible polyurethane foam can be easily obtained. [Examples]

[0053] The present invention will be described more specifically below based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" in this text refer to mass.

[0054] [Preparation of polyol compositions] (Examples 1-4, Comparative Examples 1-3) After purging a reactor equipped with a stirrer, condenser, nitrogen inlet tube, and thermometer with nitrogen, 97 g of polyol 1, 3.0 g of polyol 2, 1.2 g of catalyst 1, 1.0 g of foam stabilizer 1, and 5.4 g of water were charged and stirred at 23°C for 0.5 hours to obtain polyol composition (P-1). Other polyol compositions (P-2 to P-7) were prepared in the same manner as P-1.

[0055] Of the raw materials shown in Table 1, the liquid temperatures of the isocyanate component (E) and the mixture of all raw materials except isocyanate component (E) (polyol compositions (P-1) to (P-7)) were adjusted to 24°C to 26°C, respectively. A predetermined amount of polyisocyanate component (E) was added to the polyol compositions (P-1) to (P-7), mixed for 5 seconds in a mixer (7000 rpm), and then injected into a mold to foam flexible polyurethane foam. After that, the foam was removed from the mold, and the physical properties of the resulting flexible polyurethane foam were measured. The NCO Index in Table 1 is the ratio of the number of moles of NCO groups to the number of moles of active hydrogen atoms present in the flexible polyurethane foam forming composition.

[0056] [Foaming conditions] Mold temperature: 60-70℃ Mold shape: 400mm x 400mm x 100mm Mold material: Aluminum

[0057] [Raw materials used] • Isocyanate 1: MDI content 89%, isomer content 38%, polyphenylene polymethylene polyisocyanate content 11% • Isocyanate 2: Diphenylmethane diisocyanate with 100% MDI content and 55% isomer content. • Isocyanate 3: MDI content 70%, isomer content 29%, polyphenylene polymethylene polyisocyanate content 30% • Polyol 1: Polyoxyethylene polyoxypropylene polyol (manufactured by Tosoh Corporation, product name: NEF-693) with average functional group count = 3.0, hydroxyl value = 24 (mgKOH / g), terminal primary status = 84 mol%, oxyethylene units = 14.6 mass%, and total unsaturation degree 0.03 meq. / g. • Polyol 2: Polyoxyethylene polyoxypropylene polyol (manufactured by Sanyo Chemical Industries, Ltd., product name: Sannix FA-159) with an average number of functional groups of 3.0, a hydroxyl value of 24 (mgKOH / g), terminal primary status of 51 mol%, oxyethylene units of 70% by mass, and a total unsaturation of 0.03 meq. / g. • Polyol 3: Polyoxyethylene polyoxypropylene polyol (manufactured by Toho Chemical Industry Co., Ltd., product name: Toho Polyol QB-8000) with average functional group count = 4.0, hydroxyl value = 28 (mgKOH / g), terminal primary status = 79 mol%, oxyethylene units = 80% by mass, and total unsaturation degree of 0.01 meq. / g. Catalyst 1: 1,2-dimethylimidazole, [foaming reaction rate constant / resin formation reaction rate constant] = 0.076 • Catalyst 2: 33% triethylenediamine dipropylene glycol solution, [Foaming reaction rate constant / Resin formation reaction rate constant] = 0.132 • Foam stabilizer 1: Silicone-based foam stabilizer (manufactured by Momentive, product name: L-3641LF) • Foam stabilizer 2: Silicone-based foam stabilizer (manufactured by Momentive, product name: L-3627) • Foam stabilizer 3: Silicone-based foam stabilizer (manufactured by Momentive, product name: Y-10366)

[0058] [Moldability evaluation] In the moldability evaluation in Table 1, A means that the soft polyurethane foam was molded without shrinkage or roughness occurring on the surface or inside of the foam after demolding, while B means that shrinkage, surface roughness, or other phenomena occurred in the polyurethane mold foam.

[0059] [Apparent Density] The results were obtained using the method described in JIS K6400.

[0060] [25% Compression Hardness (25% ILD) of Skinned Foam Test Specimens] The results were obtained using Method B described in JIS K6400. Note that the skinned foam test specimens are molded foam produced using the method described above, and refer to foam with the skin still attached without being cut or otherwise altered.

[0061] [Tear strength] The measurements were taken using the method described in JIS K6400.

[0062] [Moist heat compressive strain] The measurements were taken using the method described in JIS K6400.

[0063] [Growth rate] The measurements were taken using the method described in JIS K6400.

[0064] [Table 1]

[0065] As shown in Table 1, according to Examples 1-4, the value of [foaming reaction rate constant / resin formation reaction rate constant] was 0.090 or less, and the 25% compression hardness was 100 N / 314 cm. 2 The following results in a flexible polyurethane foam with a tear strength of 4.5 N / cm or more, an elongation of 100% or more, and a moist heat compression strain of 25% or less. On the other hand, in Comparative Examples 1 and 2, when the value of [foaming reaction rate constant / resinification reaction rate constant] exceeds 0.090, the stability of the cells in the foam decreases significantly, and moldability deteriorates, resulting in roughness on the surface and inside the polyurethane foam. On the other hand, in Comparative Example 3, the tear strength is less than 4.5 N / cm and the moist heat compression strain exceeds 25%. As is clear from comparing the above examples and comparative examples, a molded article can be obtained that has a hardness that provides good ride comfort when used, for example, as a seat back material, and has desirable physical properties.

Claims

1. Polyol component (A), Catalyst (B), Foam stabilizer (C), Foaming agent (D), It contains polyisocyanate component (E), The ratio of the foaming reaction rate constant to the resinification reaction rate constant of the catalyst (B) (foaming reaction rate constant / resinification reaction rate constant) is 0.090 or less. The aforementioned polyisocyanate component (E) is Diphenylmethane diisocyanate (E-1) and, It contains the optional component polymethylene polyphenylene polyisocyanate (E-2), In the aforementioned polyisocyanate component (E), The content of the diphenylmethane diisocyanate (E-1) is 75% by mass or more and 100% by mass or less, relative to the total amount of the polyisocyanate component (E). The content of the aforementioned polymethylene polyphenylene polyisocyanate (E-2) is 0% by mass or more and 25% by mass or less, relative to the total amount of the polyisocyanate component (E). A flexible polyurethane foam-forming composition wherein the total content of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the diphenylmethane diisocyanate (E-1) is 20% by mass or more and 60% by mass or less based on the total amount of the diphenylmethane diisocyanate (E-1).

2. The flexible polyurethane foam-forming composition according to Claim 1, wherein the apparent density measured under the following conditions (1) to (4) is 25 kg / m³ or more and 40 kg / m³ or less. (1) The polyol component (A), the catalyst (B), the foam stabilizer (C), and the blowing agent (D) are each adjusted to 24°C to 26°C. (2) Mix the polyisocyanate component (E) with the mixture for 5 seconds in a mixer that rotates at 7,000 revolutions per minute. (3) The material is injected into a mold with a mold temperature of 60-70°C, a mold shape of 400 mm x 400 mm x 100 mm, and made of aluminum, and then foamed. (4) Remove from the mold and determine the apparent density according to the method described in JIS K6400.

3. The flexible polyurethane foam-forming composition according to claim 1, wherein the total amount of 2,2'-diphenylmethane diisocyanate and 2,4'-diphenylmethane diisocyanate in the diphenylmethane diisocyanate (E-1) is 30% by mass or more and 50% by mass or less based on the total amount of the diphenylmethane diisocyanate (E-1).

4. A flexible polyurethane foam, which is a foamed molded article of a flexible polyurethane foam-forming composition according to any one of claims 1 to 3.

5. Apparent density is 25 kg / m³ ３ More than 40kg / m ３ The following: The 25% compression hardness of the skinned foam test specimen, measured according to Method B described in JIS K6400, was 100 N / 314 cm. ２ The following is the flexible polyurethane foam according to claim 4.

6. The elongation rate measured according to the method described in JIS K6400 is 100% or more. The tear strength is 4.5 N / cm or more. The flexible polyurethane foam according to claim 4 or 5, wherein the moist heat compression strain is 25% or less.

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