Polyurethane foam and impact absorbing member

Abstract

A polyurethane foam is a reaction product of a raw material composition containing a polyether polyol and an isocyanate, the polyether polyol containing a polyether polyol (A) having a hydroxyl value of 100 mgKOH / g or less and an oxirane content of 60% by mass or more, the content of the polyether polyol (A) being 65 to 75% by mass relative to the total amount of the polyether polyol, and the density being 110 kg / m 3 The above.

Description

Technical Field

[0001] This disclosure relates to a polyurethane foam and an impact-absorbing component.

[0002] Background Technology Polyurethane foam is a foam obtained by mixing a polyol with hydroxyl groups with a polyisocyanate with isocyanate groups and simultaneously carrying out a foaming reaction and a resinification reaction.

[0003] For example, Japanese Patent Application Publication No. 2021-147461 discloses a polyurethane foam obtained by reacting an isocyanate compound (I) containing at least two or more isocyanate groups in one molecule, a polyol compound (II) as a chain extender, and a polyol (III) containing two or more hydroxyl groups in one molecule. The polyol (III) is characterized in that the polyol (III) comprises a polycarbonate polyol (A) having an oxoalkylene diol-derived structural unit represented by formula (A1).

[0004] Japanese Patent Application Publication No. 2-175713 discloses a method for manufacturing flexible polyurethane foam, characterized in that, when a mixture consisting of a polyol, a catalyst, a foam stabilizer, a foaming agent, and other suitable additives is reacted with a polyisocyanate to manufacture polyurethane foam, a polyether polyol with an average molecular weight of 400 or more and 2000 or less and an average number of functional groups of 2 or more and 3.5 or less is used as the polyol.

[0005] Japanese Patent Application Publication No. 2001-40058 discloses a method for manufacturing polyurethane foam, characterized in that polyol, catalyst, foaming agent, and MDI-based prepolymer or other isocyanate mixed with MDI-based isocyanate are added to make the isocyanate index 35 to 95, and then mixed and foamed.

[0006] Japanese Patent Application Publication No. 2000-290344 discloses a flexible polyurethane foam, characterized in that, in the flexible polyurethane foam obtained from an organic polyisocyanate (A), an active hydrogen compound (B), and a blowing agent, the active hydrogen compound (B) is a mixture of the following or a polymeric polyol obtained from the mixture, wherein, (b1) a polyether polyol with a hydroxyl value of 40 mg KOH / g or more and 120 mg KOH / g or less, an average number of functional groups of 2 or more and 4 or less, and a molar addition polymerization ratio of an epoxide with 3 or more carbon atoms to ethylene oxide of 50 / 50 to 10 / 90; (b2) a polyether polyol with a hydroxyl value of 410 mg KOH / g or more and 600 mg KOH / g or less, and an average number of functional groups of 2 or more and 8 or less; (b3) a polyether polyol with a hydroxyl value of 20 mg KOH / g or more and 170 mg KOH / g or more. Polyether polyols with an average number of functional groups of 2 or more and 4 or less and a KOH content of less than mg / g, when the total weight of (b1), (b2), and (b3) is set to 100, have the following mixing ratios: (b1) 30-85, (b2) 5-50, and (b3) 10-40.

[0007] Japanese Patent Application Publication No. 2015-134970 discloses a type of padding for clothing. This padding is formed by molding polyurethane foam raw material containing polyol, polyisocyanate, catalyst, and foaming agent. The characteristic feature is that, for this padding, if the content of ethylene oxide units is defined as the EO rate when the total amount of ethylene oxide units is set to 100% by mass, then the EO rate of the polyol is 15% to 55%, including high EO rate polyols with a content of 50% by mass or more when the total amount of polyol is set to 100% by mass.

[0008] Japanese Patent Application Publication No. 5-320305 discloses a dilatational polyurethane, characterized in that the dilatational polyurethane is obtained by reacting a polyester polyol with 2 functional groups, a low molecular weight chain extender with 2 functional groups, and an isocyanate, and the dilatation coefficient obtained by the calculation method shown below is 1.0 or higher.

[0009] Japanese Patent Application Publication No. 2019-94382 discloses a resin composition comprising polyurethane, which is a resin composition with excellent dilatation properties.

[0010] Japanese Patent Application Publication No. 2024-80597 describes a polyurethane molded body with excellent expansion flow characteristics. Summary of the Invention

[0011] The problem that the invention aims to solve However, the physical properties related to impact absorption and followability in the polyurethane foams described in the aforementioned literature are insufficient.

[0012] To improve shock absorption, for example, by increasing the proportion of low molecular weight polyols, there is a tendency for the material to harden and for its followability to decrease.

[0013] In general, increasing the thickness or density of polyurethane foam is effective in improving impact absorption. However, while increasing the thickness of the polyurethane foam improves impact absorption, it also increases its volume. Conversely, increasing the density of the polyurethane foam improves impact absorption, but it also increases its weight. Depending on the application of the polyurethane foam, its thickness may be limited or lightweight requirements may be necessary; even under these conditions, polyurethane foam with excellent impact absorption is still required.

[0014] This disclosure was made in view of the above circumstances, and its objective is to provide a polyurethane foam with excellent impact absorption and followability, and an impact-absorbing member having the above-mentioned polyurethane foam.

[0015] Methods for solving problems This disclosure includes the following methods.

[0016] <1> A polyurethane foam, wherein, This polyurethane foam is a reactant comprising a raw material composition of polyether polyol and isocyanate. Polyether polyols include polyether polyols (A) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of more than 60% by mass. The content of polyether polyol (A) relative to the total amount of polyether polyol is 65% to 75% by mass. Density is 110 kg / m³ 3 above.

[0017] <2> The polyurethane foam according to claim 1, wherein, The polyether polyol also includes at least one selected from the group consisting of polyether polyol (B) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of less than 50% by mass, and polyether polyol (C) with a hydroxyl value of more than 200 mgKOH / g and an ethylene oxide content of less than 50% by mass.

[0018] <3> According to <1> or <2>, the polyurethane foam, wherein, The rebound elasticity based on JIS K 6400-3 is less than 15%.

[0019] <4> The polyurethane foam according to any one of <1> to <3>, wherein, Asker C has a hardness of less than 50.

[0020] <5> An impact absorbing component, wherein, The impact-absorbing component comprises any one of <1> to <4> polyurethane foam.

[0021] Technical effect According to this disclosure, a polyurethane foam with excellent impact absorption and followability is provided, as well as an impact-absorbing component having the aforementioned polyurethane foam. Detailed Implementation

[0022] In this specification, the numerical range represented by “~” refers to the range included by setting the values ​​before and after “~” as the minimum and maximum values, respectively.

[0023] In the numerical ranges described in this specification, the upper or lower limit value recorded in a certain numerical range can be replaced with the upper or lower limit value of other numerical ranges described in different periods. Furthermore, in the numerical ranges described in this specification, the upper or lower limit value recorded in a certain numerical range can be replaced with the values ​​shown in the embodiments.

[0024] In this specification, the amount of each component in the composition, unless otherwise specified, refers to the total amount of the multiple substances present in the composition, in the case where multiple substances corresponding to each component are present in the composition.

[0025] In this specification, a combination of two or more preferred methods is a more preferred method.

[0026] In this specification, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0027] [Polyurethane foam] The polyurethane foam disclosed herein is a reactant comprising a raw material composition of polyether polyol and isocyanate. The polyether polyol comprises polyether polyol (A) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of more than 60% by mass. The content of polyether polyol (A) is 65% to 75% by mass relative to the total amount of polyether polyol, and the density is 110 kg / m³. 3 above.

[0028] The polyurethane foam disclosed herein can balance impact absorption and follow-through properties.

[0029] The polyurethane foam disclosed herein can be either molded polyurethane foam or low-resilience molded polyurethane foam. Molded polyurethane foam refers to polyurethane foam in which raw material is injected into a covered mold and foams and forms along the mold. A key feature of molded polyurethane foam is its ability to foam and form in a short time.

[0030] The polyurethane foam disclosed herein is a reactant comprising a raw material composition of polyether polyol and isocyanate.

[0031] In addition to polyether polyols and isocyanates, the raw material composition may also contain at least one selected from crosslinking agents, catalysts, foam stabilizers and foaming agents.

[0032] <Polyether polyols> The raw material composition contains at least one polyether polyol. The polyether polyol contained in the raw material composition is a polyether polyol (A) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of more than 60% by mass. Hereinafter, the ethylene oxide content will also be referred to as "EO rate".

[0033] (Polyether polyol (A)) The hydroxyl value of the polyether polyol (A) is 100 mg KOH / g or less, preferably 50 mg KOH / g or less, and more preferably 40 mg KOH / g or less. From the viewpoint of ease of mixing with other materials, the hydroxyl value of the polyether polyol (A) is preferably 20 mg KOH / g or more. By making the hydroxyl value of the polyether polyol (A) 100 mg KOH / g or less, a good polyurethane foam can be obtained.

[0034] In this disclosure, the hydroxyl value is measured using a method based on JIS K 0070:1992.

[0035] The EO content of the polyether polyol (A) is 60% by mass or more, preferably 70% by mass or more. From the viewpoint of good foaming properties, the EO content of the polyether polyol (A) is preferably 80% by mass or less. By ensuring that the EO content of the polyether polyol (A) is 60% by mass or more, the impact absorption is particularly excellent.

[0036] In this disclosure, EO rate refers to the content (mass %) of ethylene oxide units in the polyether polyol (A) when converted by mass.

[0037] Polyether polyols (A) may also contain epoxide units other than ethylene oxide units. Examples of other epoxide units include propylene oxide and butane oxide.

[0038] The polyether polyol (A) preferably comprises ethylene oxide units and propylene oxide units.

[0039] The number average molecular weight of the polyether polyol (A) is not particularly limited. From the viewpoint of ease of mixing and spreadability of the raw materials, the number average molecular weight of the polyether polyol (A) is preferably 20,000 or less, more preferably 10,000 or less. Furthermore, from the viewpoint of moldability and conformability, the number average molecular weight of the polyether polyol (A) is preferably 1,000 or more, more preferably 2,500 or more, and even more preferably 4,000 or more.

[0040] In this disclosure, the number-average molecular weight is a polystyrene conversion value obtained by using gel permeation chromatography (GPC) with an EXTREMA column (manufactured by Nippon Spectrophotometry Co., Ltd.), detecting the solvent THF (tetrahydrofuran) and a differential refractometer, and using polystyrene as a standard substance for conversion. It should be noted that the number-average molecular weight can also be the catalog value.

[0041] The number of functional groups in the polyether polyol (A) is not particularly limited. From the viewpoint of reactivity and responsiveness, the number of functional groups in the polyether polyol (A) is preferably 2 to 5, more preferably 2 to 4, and even more preferably 2 to 3.

[0042] In this disclosure, the number of functional groups refers to the average number of active hydrogen groups possessed by the polyether polyol. When the polyol is a commercially available product, the catalog value is used as the number of functional groups.

[0043] The content of polyether polyol (A) is 65-75% by mass relative to the total amount of polyether polyol.

[0044] By setting the content of polyether polyol (A) within the above-mentioned range, polyurethane foam with excellent impact absorption and conformability can be obtained. By setting the content of polyether polyol (A) to 65% by mass or more, conformability and moldability are improved. By setting the content of polyether polyol (A) to 75% by mass or less, impact absorption is improved.

[0045] (Polyether polyols (B) (C)) The polyether polyol preferably further comprises at least one selected from the group consisting of polyether polyol (B) with a hydroxyl value of less than 100 mgKOH / g and an EO rate of less than 50% by mass, and polyether polyol (C) with a hydroxyl value of more than 200 mgKOH / g and an EO rate of less than 50% by mass.

[0046] By further comprising at least one selected from the group consisting of polyether polyol (B) and polyether polyol (C), polyurethane foam with superior impact absorption and followability can be obtained.

[0047] In particular, the polyether polyol preferably includes polyether polyol (A), polyether polyol (B) and polyether polyol (C).

[0048] The hydroxyl value of the polyether polyol (B) is 100 mgKOH / g or less, preferably 50 mgKOH / g or less, and more preferably 40 mgKOH / g or less. From the viewpoint of moldability and conformability, the hydroxyl value of the polyether polyol (B) is preferably 20 mgKOH / g or more.

[0049] The hydroxyl value of the polyether polyol (C) is 200 mgKOH / g or more, preferably 300 mgKOH / g or more, and more preferably 400 mgKOH / g or more. From a follow-up point of view, the hydroxyl value of the polyether polyol (C) is preferably 600 mgKOH / g or less.

[0050] The EO content of the polyether polyol (B) is less than 50% by mass, preferably 35% by mass or less, and more preferably 20% by mass or less. From a reactivity point of view, the EO content of the polyether polyol (B) is preferably 5% by mass or more.

[0051] The EO percentage of the polyether polyol (C) is less than 50% by mass, preferably less than 30% by mass, and more preferably less than 10% by mass. The EO percentage of the polyether polyol (C) can also be 0% by mass.

[0052] Polyether polyols (B) may contain epoxide units other than ethylene oxide units. Examples of other epoxide units include propylene oxide and butane oxide.

[0053] The polyether polyol (B) preferably comprises ethylene oxide units and propylene oxide units.

[0054] Polyether polyols (C) may also contain epoxide units other than ethylene oxide units. Examples of other epoxide units include propylene oxide and butane oxide.

[0055] The number average molecular weight of the polyether polyol (B) is not particularly limited. From the viewpoint of ease of mixing and spreadability of the raw materials, the number average molecular weight of the polyether polyol (B) is preferably 20,000 or less, more preferably 10,000 or less. Furthermore, from the viewpoint of moldability, the number average molecular weight of the polyether polyol (B) is preferably 1,000 or more, more preferably 2,500 or more, and even more preferably 4,000 or more.

[0056] The number-average molecular weight of the polyether polyol (C) is not particularly limited. From the viewpoint of moldability and low resilience, the number-average molecular weight of the polyether polyol (C) is preferably 800 or less, more preferably 550 or less. Furthermore, from the viewpoint of moldability and conformability, the number-average molecular weight of the polyether polyol (C) is preferably 200 or more, more preferably 300 or more, and even more preferably 350 or more.

[0057] The number of functional groups in the polyether polyol (B) is not particularly limited. From the viewpoint of reactivity and responsiveness, the number of functional groups in the polyether polyol (B) is preferably 2 to 5, more preferably 2 to 4, and even more preferably 2 to 3.

[0058] The number of functional groups in the polyether polyol (C) is not particularly limited. From the viewpoint of reactivity and responsiveness, the number of functional groups in the polyether polyol (C) is preferably 2 to 5, more preferably 2 to 4, and even more preferably 2 to 3.

[0059] The content of polyether polyol (B) relative to the total amount of polyether polyol is preferably 5% to 20% by mass, more preferably 10% to 15% by mass.

[0060] The content of polyether polyol (C) relative to the total amount of polyether polyol is preferably 10% to 25% by mass, more preferably 15% to 20% by mass.

[0061] When the polyether polyol comprises both polyether polyol (B) and polyether polyol (C), the mass ratio of the content of polyether polyol (B) to the content of polyether polyol (C) (polyether polyol (B) / polyether polyol (C)) is preferably 0.45 to 0.90, more preferably 0.5 to 0.8. When the mass ratio is within the above range, the shock absorption and followability are further improved.

[0062] <Isocyanate> The raw material composition contains at least one isocyanate. The isocyanate contained in the raw material composition is not particularly limited. The isocyanate may be a methylenediphenyl diisocyanate (MDI)-based polyisocyanate or a toluene diisocyanate (TDI)-based polyisocyanate.

[0063] Examples of MDI-based polyisocyanates include monomeric MDI such as 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 4,4'-diphenylmethane diisocyanate (4,4'-MDI); polymerized MDI, which is a mixture of diphenylmethane diisocyanate and polymethylene polyphenylene polyisocyanate; and polyurethane modified, carbodiimide modified, urea modified, carbamate modified, biuret modified, and isocyanurate modified forms of these polyisocyanates.

[0064] In addition, isocyanate can also be an MDI prepolymer obtained by reacting the above-mentioned MDI-based polyisocyanate with a polyol.

[0065] Examples of TDI-based polyisocyanates include 2,4-TDI, 2,6-TDI, and mixtures of 2,4-TDI and 2,6-TDI. The content ratio of 2,4-TDI to 2,6-TDI (2,4-TDI / 2,6-TDI) is preferably 100 / 0 to 50 / 50 (mass ratio), and more preferably 80 / 20 to 65 / 35.

[0066] The isocyanate preferably includes polyurethane-modified MDI.

[0067] The isocyanate index (INDEX) is preferably 90 to 110, more preferably 95 to 105, and even more preferably 96 to 103.

[0068] The isocyanate index is 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 water (used as a blowing agent), and then multiplying the result by 100. In other words, the isocyanate index is calculated as [NCO equivalent of isocyanate / active hydrogen equivalent × 100].

[0069] <Cross-linking agent> The raw material composition may also contain at least one crosslinking agent. Crosslinking agents, for example, have the function of increasing the hardness of polyurethane foam.

[0070] Examples of crosslinking agents include amines such as diethanolamine and polyethylene polyamines; and polyols such as trimethylolpropane, glycerol, 1,4-butanediol, and diethylene glycol.

[0071] The crosslinking agent preferably has 2 to 4 functional groups.

[0072] The content of the crosslinking agent can also be 1.0 to 2.0 parts by weight relative to 100 parts by weight of polyether polyol. The content of the crosslinking agent is preferably 1.1 to 1.9 parts by weight, more preferably 1.2 to 1.8 parts by weight, even more preferably 1.3 to 1.7 parts by weight, and particularly preferably 1.4 to 1.6 parts by weight.

[0073] <Catalyst> The raw material composition may also contain at least one catalyst.

[0074] Examples of catalysts include aliphatic amine catalysts, aromatic amine catalysts, and metal catalysts such as tin octoate.

[0075] The catalyst content can also be 0.5 to 1.5 parts by mass relative to 100 parts by mass of polyether polyol. The catalyst content is preferably 0.6 to 1.4 parts by mass, more preferably 0.7 to 1.3 parts by mass, even more preferably 0.8 to 1.2 parts by mass, and particularly preferably 0.9 to 1.1 parts by mass.

[0076] <Foam stabilizer> The raw material composition may also contain at least one foam stabilizer.

[0077] Foam stabilizers can be any foam stabilizers commonly used in the raw materials of polyurethane foam. Examples of foam stabilizers include silicone compounds and nonionic surfactants.

[0078] The content of the foam stabilizer relative to 100 parts by weight of polyether polyol can also be 0 to 0.9 parts by weight. The content of the foam stabilizer is preferably 0.2 to 0.8 parts by weight, more preferably 0.3 to 0.7 parts by weight, even more preferably 0.4 to 0.6 parts by weight, and particularly preferably 0.45 to 0.55 parts by weight.

[0079] <Foaming Agent> The raw material composition may also contain at least one foaming agent.

[0080] Regarding foaming agents, examples include water, Freon substitutes, and hydrocarbons such as pentane. Water is particularly preferred as a foaming agent. When water is used, carbon dioxide gas is generated during the reaction of the polyether polyol with the isocyanate, and foaming occurs using this carbon dioxide gas.

[0081] The water content as a blowing agent can be 1.0 to 3.0 parts by weight relative to 100 parts by weight of polyether alcohol. The water content as a blowing agent is preferably 1.2 to 2.8 parts by weight, more preferably 1.4 to 2.6 parts by weight, even more preferably 1.6 to 2.4 parts by weight, and particularly preferably 1.8 to 2.2 parts by weight.

[0082] <Other Ingredients> The raw material composition may also contain other components besides those mentioned above.

[0083] Other components include, for example, fluxing agents, flame retardants, and antioxidants.

[0084] <Physical Properties> The polyurethane foam involved in this disclosure may also be a flexible polyurethane foam.

[0085] (density) The density of polyurethane foam is 110 kg / m³. 3 above.

[0086] By making the density 110 kg / m³ 3 In summary, it exhibits excellent shock absorption and tracking performance.

[0087] The preferred density is 110 kg / m³ 3 ~300 kg / m 3 More preferably 125 kg / m 3 ~250 kg / m 3 A further preferred value is 140 kg / m³. 3 ~200 kg / m 3 .

[0088] In this disclosure, density is measured based on JIS K 7222:2005.

[0089] (Rebound coefficient) The resilience of the polyurethane foam is preferably less than 15%, more preferably less than 10%, and even more preferably less than 8%. There is no particular limitation on the lower limit of the resilience, for example, it is 4%.

[0090] In this disclosure, the spring rate of elasticity is measured based on JIS K 6400-3:2011.

[0091] (Asker C hardness) The Asker C hardness of the polyurethane foam is preferably less than 50, more preferably less than 40. There is no particular limitation on the lower limit of the Asker C hardness, for example, it can be 8.

[0092] In this disclosure, the Asker C hardness is measured at 23 °C based on JIS K 7312:1996.

[0093] <Manufacturing Method of Polyurethane Foam> Polyurethane foam can be manufactured, for example, by a known foaming method that involves mixing raw material compositions and reacting polyether polyols and isocyanates. Foaming methods include slab foaming and die foaming. Either foaming method can be used, but die foaming is preferred. Die foaming involves filling the mixed raw material composition into a mold (molding die) and foaming within the mold. Die foaming of polyurethane is suitable for molding articles with complex three-dimensional shapes.

[0094] The thickness of the manufactured polyurethane foam is not particularly limited. When the foaming method is mold foaming, any thickness that can be produced by mold foaming is acceptable. The thicker the polyurethane foam, the higher its impact absorption. However, the polyurethane foam of this disclosure exhibits excellent impact absorption even at a thickness of approximately 10 mm.

[0095] <Uses> There are no limitations on the articles in which the polyurethane foam of this disclosure is applied. The polyurethane foam of this disclosure is suitable for sports protectors or gear for joints such as elbows and knees; helmet padding, seat cushions, car headrests, armrests, motorcycle saddles, seats, bicycle saddles; clothing padding (e.g., chest pads), etc. In particular, the polyurethane foam of this disclosure, which exhibits excellent shock absorption and conformability even at thicknesses of 10 mm or less (e.g., 5 mm, 6 mm, 7 mm, 8 mm, 9 mm), is suitable for protectors or gear for joints such as elbows and knees; helmet padding; clothing padding (e.g., chest pads), and other components that support at least a portion of the human body.

[0096] [Impact Absorbing Components] The impact-absorbing component disclosed herein comprises the polyurethane foam disclosed herein.

[0097] The polyurethane foam disclosed herein has excellent impact absorption and followability, and therefore the impact absorbing component disclosed herein is excellent in terms of impact absorption and followability.

[0098] As shock-absorbing components, they can be used in sports protective devices or gear that protect joints such as elbows and knees; helmet pads, seat cushions, car headrests, armrests, motorcycle saddles, seats, bicycle saddles; and clothing pads (e.g., chest pads).

[0099] Example The present disclosure will be described in more detail below through embodiments, but the present disclosure is not limited to the following embodiments as long as it does not depart from its spirit.

[0100] [Manufacturing of polyurethane foam] A raw material composition was prepared by mixing the raw materials in the proportions (parts by mass) shown in Table 1, and polyurethane foam was manufactured by foaming through a mold.

[0101] The details of the raw materials are as follows.

[0102] Polyether polyol (A): Product name "CP1421", manufactured by Dow Chemical Company, EO percentage 75% by mass, number of functional groups 3, hydroxyl value 35 mgKOH / g, number average molecular weight 5000 Polyether polyol (B): Product name "VORANOL 4701", manufactured by Dow Chemical Company, EO percentage 14% by mass, number of functional groups 3, hydroxyl value 35 mgKOH / g, number average molecular weight 5000 Polyether polyol (C): Product name "SANNIX GP400", manufactured by Sanyo Chemical Industry Co., Ltd., EO percentage 0% by mass, number of functional groups 3, hydroxyl value 421 mgKOH / g, number average molecular weight 400 Crosslinking agent (glycerin): Product name "Dana Explosives Glycerin", manufactured by Nippon Oil Co., Ltd. Catalyst: Amine-based catalyst, product name "DA BCO33LSI", manufactured by Evonik Ltd. Foam stabilizer: Silicone-based foam stabilizer, product name "TEGOSTAB B8738LF2", manufactured by Evonik Ltd. Isocyanate: Polyurethane-modified MDI, product name "Lupranate MP-102", manufactured by BASF INOAC Corporation, isocyanate index 100 Test pieces were cut from the obtained polyurethane foam, and the density was measured using the test pieces.

[0103] In addition, test pieces were cut from the obtained polyurethane foam, and the impact absorption, resilience, conformability, moldability, tensile strength, elongation, and viscoelasticity were evaluated using these test pieces. The measurement and evaluation methods are described below.

[0104] (density) Density was measured based on JIS K 7222:2005.

[0105] (Shock absorption) A drop weight test was conducted. Specifically, the maximum stress when a 5 kg iron ball was dropped from a height of 60 cm was measured. The evaluation criteria are as follows.

[0106] A: The maximum stress is less than 20 kN.

[0107] B: The maximum stress is above 20 kN and less than 25 kN.

[0108] C: The maximum stress is above 25 kN.

[0109] (Resilience) The resilience was measured based on JIS K 6400-3:2011.

[0110] The resilience was evaluated based on the rebound coefficient. The evaluation criteria are as follows.

[0111] A: The rebound elasticity is less than 10%.

[0112] B: The rebound elasticity is 10% or more but less than 15%.

[0113] C: The rebound elasticity is above 15%.

[0114] (Following) Based on JIS K 7312:1996, the Asker C hardness was measured at 23 °C. Followability was evaluated based on the Asker C hardness. The evaluation criteria are as follows.

[0115] A: Asker C hardness is less than 40.

[0116] B: Asker C has a hardness of 40 or higher but less than 50.

[0117] C: Asker C has a hardness of 50 or higher.

[0118] (Moldability) The moldability was evaluated by visually observing the state of polyurethane foam when fabricating test pieces measuring 400 mm × 150 mm × 10 mm. Specifically, it was confirmed whether shrinkage or surface depressions occurred without breakage. The evaluation criteria are as follows.

[0119] A: There are absolutely no problems with its formability.

[0120] B: The level has slight issues with moldability, but no problems in actual use.

[0121] C: There are problems with moldability.

[0122] (Tensile strength, elongation) Tensile tests were conducted under the following conditions, and tensile strength and elongation were measured.

[0123] Measuring equipment: Product name "AGS-J500N", manufactured by SHIMADZU Tensile speed: 100 mm / min, 500 mm / min Measurement temperature: Room temperature (23 ℃) Sample thickness: 10 mm The evaluation criteria are as follows.

[0124] -Tensile strength (100 mm / min)- A: Above 400 kPA.

[0125] B: Above 200 kPA and below 400 kPA.

[0126] C: Less than 200 kPA.

[0127] -Elongation (100 mm / min)- A: More than 130%.

[0128] B: 90% or more but less than 130%.

[0129] C: Less than 90%.

[0130] -Tensile strength (500 mm / min)- A: Above 500 kPA.

[0131] B: Above 300 kPA and below 500 kPA.

[0132] C: Less than 300 kPA.

[0133] -Elongation (500 mm / min)- A: More than 130%.

[0134] B: 90% or more but less than 130%.

[0135] C: Less than 90%.

[0136] -Difference in tensile strength- The difference in tensile strength is the absolute value of the difference between tensile strength (100 mm / min) and tensile strength (500 mm / min).

[0137] A: More than 100 kPA.

[0138] B: Above 50 kPA and below 100 kPA.

[0139] C: Less than 50 kPA.

[0140] -Ratio of tensile strength- The ratio of tensile strengths is calculated based on the following formula.

[0141] The ratio of tensile strengths = [{tensile strength (500 mm / min) - tensile strength (100 mm / min)} ÷ {tensile strength (100 mm / min)}] × 100 A: More than 30.

[0142] B: 15 or higher and less than 30.

[0143] C: Less than 15.

[0144] (Viscoelasticity) Viscoelasticity tests were conducted under the following conditions, and the temperatures at which the peak value of tanδ was obtained were recorded.

[0145] Measuring equipment: Product name "ARES-G2", manufactured by TA Instruments Temperature range: -30℃~100℃ Heating rate: 6 ℃ / min Frequency: 1 Hz fixed (0.5% strain) Sample thickness: 10 mm The evaluation criteria are as follows.

[0146] A: Above 25.0 ℃ and below 30.0 ℃.

[0147] B: 15.0 ℃ or higher and less than 25.0 ℃, or 30.0 ℃ or higher and less than 40.0 ℃.

[0148] C: less than 15.0 ℃, or above 40.0 ℃.

[0149] The evaluation results are shown in Table 1. It should be noted that in Comparative Examples 4 and 8, density could not be measured and further evaluation could not be performed because molding was not possible. In Table 1, the density and evaluation columns are marked with "-".

[0150] [Table 1]

[0151] As shown in Table 1, in Examples 1 to 3, the polyurethane foam was a reactant comprising a raw material composition containing polyether polyol and isocyanate. The polyether polyol contained polyether polyol (A), the content of which was 65-75% by mass, and the density was 110 kg / m³. 3 Therefore, it can be concluded that it has excellent shock absorption and following properties.

[0152] In particular, excellent dilatation properties were observed in Examples 1 and 2.

[0153] It should be noted that the disclosures of Japanese Patent Application No. 2024-046953, filed on March 22, 2024, and International Application PCT / JP2024 / 031917, filed on September 5, 2024, are incorporated herein by reference in their entirety. Furthermore, all documents, patent applications, and technical specifications described in this specification are incorporated herein by reference to the same extent as those specifically described herein.

Claims

1. A polyurethane foam, wherein, The polyurethane foam is a reactant comprising a raw material composition of polyether polyol and isocyanate. The polyether polyol comprises a polyether polyol (A) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of more than 60% by mass. The content of the polyether polyol (A) relative to the total amount of the polyether polyol is 65% to 75% by mass. Density is 110 kg / m³ 3 above.

2. The polyurethane foam according to claim 1, wherein, The polyether polyol further comprises at least one selected from the group consisting of polyether polyol (B) with a hydroxyl value of less than 100 mgKOH / g and an ethylene oxide content of less than 50% by mass, and polyether polyol (C) with a hydroxyl value of more than 200 mgKOH / g and an ethylene oxide content of less than 50% by mass.

3. The polyurethane foam according to claim 1 or 2, wherein, The rebound elasticity based on JIS K 6400-3 is less than 15%.

4. The polyurethane foam according to any one of claims 1 to 3, wherein, Asker C has a hardness of less than 50.

5. An impact-absorbing component, wherein, The impact-absorbing component comprises polyurethane foam according to any one of claims 1 to 4.

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