Polyurethane foam, and soles and sports shoes using the same

Abstract

To provide a polyurethane foam that is low in a storage elastic modulus and tanδ from low to high temperatures and has excellent flexibility and impact resilience, and soles and shoes including the same.SOLUTION: A polyurethane foam contains an oxyethylene structure and an oxypropylene structure. A content of unsaturated groups in a polyol fraction calculated by Corish decomposition is less than 0.08 wt.% in the polyurethane foam. The storage elastic modulus is less than 3×106 Pa and the tanδ is 0.15 or less at a frequency 10 Hz and 0-100°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyurethane foam suitable for use as a sole material for shoes. [Background technology]

[0002] Polyurethane foam is mainly produced by the reaction of isocyanate and polyol, and is widely used in a variety of applications, including cushioning for vehicles and furniture, insulation for buildings, storage tanks, ships, and other applications, structural materials, automotive interior materials such as steering wheels, and integral skin foam for shoe soles.

[0003] Examples of polyols used in polyurethane foams include polytetramethylene glycol, polyester polyols, and polyalkylene oxides.

[0004] Polyurethane foams using polyester polyols have the problems of poor water resistance due to hydrolysis because of the ester group they contain, and poor cold resistance due to a high glass transition temperature (Tg).

[0005] Polyalkylene oxides produced by addition polymerization of alkylene oxides such as propylene oxide are generally liquid and have low viscosity, and polyurethane foams using such polyalkylene oxides have excellent hydrolysis resistance and cold resistance.

[0006] Polyalkylene oxides are industrially produced by addition polymerization of alkylene oxides such as propylene oxide using an alkali metal such as potassium hydroxide as a catalyst. The polyalkylene oxides obtained by this method produce a large amount of monool as a by-product, and polyurethane foams using such polyalkylene oxides have the problem of poor impact resilience due to insufficient network formation.

[0007] Patent Document 1 discloses a shoe sole made of polyurethane foam using polyalkylene oxide with a low monool content and an unsaturation level reduced to 0.07 meq / g or less. However, the monool content was not sufficiently reduced and the molecular weight distribution was broad, so the shoe sole still had the problem of poor impact resilience.

[0008] Furthermore, polyurethane foams using polytetramethylene glycol have excellent hydrolysis resistance, cold resistance, and resilience, and are therefore suitable for use in applications where these properties are required.

[0009] Patent Document 2 proposes an integral skin foam using polytetramethylene glycol.

[0010] However, polytetramethylene glycol is normally solid at room temperature, and polyol premixes using it tend to become waxy. Therefore, they are typically heated before use in polyurethane foam molding, making them difficult to handle. Furthermore, polyurethane foams using it can exhibit crystallinity, which can result in a high storage modulus and poor flexibility depending on the operating conditions, such as low to room temperature. Improvements were needed. Furthermore, in certain environments, such as low and high temperatures, the ratio of the loss modulus E" to the storage modulus E' (tan δ) can be high, resulting in insufficient rebound resilience, limiting the operating conditions. [Patent Document 1] Japanese Patent Application Publication No. 3-47202 [Patent Document 2] International Publication No. 2016 / 167312 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above-mentioned background art, and an object of the present invention is to provide a polyurethane foam which has a low storage modulus and tan δ from low to high temperatures and which is excellent in flexibility and rebound resilience, and a sole and a shoe using the same. [Means for solving the problem]

[0012] As a result of extensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a unit having a specific structure as the main structure and controlling the storage modulus and tan δ value in a specific temperature range and at room temperature, and have thus completed the present invention.

[0013] That is, the present invention relates to the following polyurethane foam. [1] A polyurethane foam containing an oxyethylene structure and an oxypropylene structure, wherein the content of unsaturated groups in the polyol fraction calculated by Colish decomposition is less than 0.08% by weight, The storage modulus is 3×10 at a frequency of 10 Hz and in the range of 0 to 100°C. 6 A polyurethane foam having a modulus of elasticity (E") of less than 100 Pa and a ratio (tan δ) of loss modulus E" to storage modulus E' of 0.15 or less. [2] The content of the oxytetramethylene structure is less than 65% by weight, 2. The polyurethane foam according to claim 1, wherein the rebound resilience at 25°C measured in accordance with JIS K7312 is 50% or more, and the tan δ at a frequency of 10 Hz and 25°C is 0.10 or less. [3] The polyurethane foam according to [1] or [2], having a core density of 100 to 800 g / L and a rebound resilience of 60% or more at 25°C measured in accordance with JIS K7312. [4] The polyurethane foam according to any one of [1] to [3], having an average cell diameter of 50 to 150 μm and a closed cell structure of 50% or more. [5] Polyurethane that is a reaction product of at least a polyol and a polyisocyanate, The polyol contains a polyether polyol (A) containing an oxyethylene group and an oxypropylene group, The degree of unsaturation of the polyether polyol (A) is 0.010 meq / g or less. The polyurethane foam according to any one of [1] to [4]. [6] The polyurethane foam according to [5], wherein the weight ratio of oxyethylene groups to oxypropylene groups in the polyether polyol (A) is in the range of 1:99 to 49:51, the ratio of primary hydroxyl groups is 40 to 99%, and the number average molecular weight calculated from the hydroxyl value is in the range of 1,500 to 30,000. [7] The polyurethane foam according to [5] or [6], wherein the polyisocyanate is a modified isocyanate. [8] A shoe sole made of the polyurethane foam according to any one of [1] to [7]. [9] A shoe sole including an outsole, an insole, and a midsole, wherein the midsole is a molded product of the polyurethane foam according to any one of [1] to [7].

[10] A sports shoe having a shoe sole including an outsole, an insole, and a midsole, wherein the insole is a molded product of the polyurethane foam according to any one of [1] to [7].

[11] A sports shoe having the shoe sole described in any one of [8] to

[10] . [Effects of the Invention]

[0014] The polyurethane foam of the present invention has low hardness from low to high temperatures and excellent resilience.

[0015] Furthermore, soles made from this material are flexible and have excellent cushioning and resilience regardless of environmental conditions such as temperature, and when used in shoes, they not only provide excellent comfort and safety, but also reduce energy loss during running and are excellent at reducing fatigue. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. <Polyurethane foam> The polyurethane foam of one embodiment of the present invention contains an oxyethylene structure and an oxypropylene structure, and has a storage modulus of 3×10 at any temperature in the range of 0 to 100° C. under a frequency condition of 10 Hz. 6It is characterized by having a tensile strength of less than Pa and a tan δ of 0.15 or less.

[0017] The raw materials for such polyurethane foam are not particularly limited, but can be obtained by using polyol, polyisocyanate, and a foaming agent, and it is preferable that the polyurethane foam has the structure and properties described below.

[0018] The polyurethane foam can be produced by reacting raw materials such as the polyol and polyisocyanate having the oxypropylene and oxyethylene groups described above in the presence of auxiliary materials such as the blowing agent, foam stabilizer, viscosity modifier, and urethanization catalyst, as needed, without any particular limitation, as long as the polyurethane foam contains oxypropylene and oxyethylene groups and has specific properties.

[0019] Therefore, the polyurethane foam may contain secondary materials such as a blowing agent, a foam stabilizer, a viscosity modifier, and a urethanization catalyst, and preferably contains 85 to 99.9 wt% of a polyurethane component, which is a reaction product of a polyol, a blowing agent, a polyisocyanate, etc., and 0.1 to 15 wt% of the secondary materials. Among these, it is particularly preferred to contain 85 to 99.9 wt% of a polyurethane component, which is a reaction product of a polyol, a blowing agent, a polyisocyanate, etc., 0.01 to 5 wt% of a foam stabilizer component, 0.001 to 15 wt% of a urethanization catalyst, and 0.001 to 0.5 wt% of an antioxidant, in order to form cells with a good cell shape and to easily exhibit good mechanical properties.

[0020] Furthermore, the potassium content in the polyurethane foam is preferably less than 50 ppm, more preferably less than 20 ppm, because the cell structure tends to be uniform and the impact resilience tends to be high.

[0021] The polyurethane foam has an oxyethylene structure and an oxypropylene structure as essential components, but may be derived from either a polyol or an isocyanate, without any particular limitation.

[0022] By containing an oxyethylene structure in addition to an oxypropylene structure, a polyurethane foam is formed with a composition in which the polyol components react uniformly, and even if it contains structures that are prone to crystallization, such as an oxytetramethylene structure or an oxyethylene structure, crystallization is easily inhibited, and the storage modulus at low temperatures and room temperature is low, so flexibility can be exhibited from low temperatures to room temperature.

[0023] The content of the oxyethylene structure contained in the polyurethane foam is not particularly limited, but is preferably 1 to 40% by weight, more preferably 3 to 30% by weight, and most preferably 5 to 20% by weight in the polyurethane foam.

[0024] The content of the oxypropylene structure contained in the polyurethane foam is not particularly limited, but is preferably 15 to 70% by weight, more preferably 20 to 60% by weight, and most preferably 25 to 55% by weight.

[0025] The content of unsaturated groups contained in the polyurethane foam, calculated by Colish decomposition, is less than 0.08% by weight, preferably less than 0.03% by weight, and most preferably in the range of 0.0001 to less than 0.005% by weight.

[0026] If the content of unsaturated groups is 0.08% by weight or more, the tackiness becomes large and the tan δ becomes high, making it difficult to use.

[0027] Qualitative and quantitative analysis by Corish degradation is a commonly known method for analyzing polyurethane resins. (P.J. Corish, Anal. Chem. 31, (8), 1298 (1959)) This method allows the constituent components of the resin to be determined. Specifically, polyurethane resin is hydrolyzed in an alkaline aqueous solution, and the resulting decomposition product is extracted and separated with an organic solvent to separate it into water-soluble and oil-soluble components. The water-soluble components, acid and glycol, contained in the aqueous solution are then separated by pH adjustment, solvent extraction, etc., to quantitatively recover the polyester constituents. Meanwhile, the oil-soluble components, polyamine and polyether, contained in the organic solvent are separated by adsorption, solvent extraction, etc., to qualitatively identify the raw polyisocyanate, and further, the polyether component. Each fraction after Corish degradation is analyzed and calculated using standard methods, such as 1H NMR, 13C NMR, HPLC, GPC, and IR.

[0028] The contents of oxyethylene structures, oxypropylene structures, oxytetramethylene groups, unsaturated groups and aromatic structures in these polyurethane foams refer to the contents calculated by the above-mentioned qualitative and quantitative analysis method using Colish degradation.

[0029] The content of oxytetramethylene structures in the polyurethane foam is not particularly limited, but because the storage modulus of the polyurethane foam at low to room temperature tends to be low and flexibility at low to room temperature tends to be low, it is preferably less than 65% by weight of the polyurethane foam, more preferably in the range of 5 to less than 55% by weight, and most preferably in the range of 10 to less than 45% by weight. A high content of oxytetramethylene structures in the polyurethane foam tends to result in high impact resilience, but flexibility at low to high temperatures tends to be poor, and too much oxytetramethylene structure may crystallize, significantly reducing flexibility at low temperatures.

[0030] Since the polyurethane foam tends to have high impact resilience, it is preferable that the polyurethane foam contains an aromatic structure, more preferably one or more of a methylenediphenylene structure, a 2,4-tolylene structure, a 2,5-tolylene structure, and a xylylene structure, and most preferably a methylenediphenylene structure. The content of the aromatic structure contained in the polyurethane foam is not particularly limited, but is preferably 5 to 60% by weight of the polyurethane foam, more preferably 10 to 50% by weight, and most preferably in the range of 20 to 40% by weight.

[0031] The number average molecular weight of the polyurethane foam is not particularly limited, but is preferably at least 30,000, more preferably at least 50,000, and most preferably at least 100,000. The number average molecular weight of the polyurethane foam refers to the number average molecular weight in terms of polystyrene determined by GPC measurement using dimethylformamide (DMF) as a solvent and polystyrene as a standard substance, and if insoluble matter is present, it is the number average molecular weight of the DMF-soluble component (sol fraction).

[0032] The gel fraction of the polyurethane foam is not particularly limited, but is in the range of 99.5% or less, and is preferably in the range of 0 to 70%, more preferably in the range of 0 to 40%, and most preferably in the range of 0 to 20%, because this makes it easier to obtain a polyurethane foam that is flexible and has excellent cushioning properties. The gel fraction of the polyurethane foam is expressed as the ratio (%) of the insoluble matter that remains undissolved when 0.5 g of the polyurethane foam is added to 100 ml of ethyl acetate and allowed to stand for 7 days.

[0033] <Method of manufacturing polyurethane foam> Examples of methods for producing the polyurethane foam include known methods such as slab foaming, mold foaming, injection foaming, spray foaming, panel foaming, reaction injection molding, etc. Alternatively, the polyurethane foam can be produced by adding a blowing agent to a pre-prepared polyurethane such as TPU and foaming it by heat or a chemical reaction.

[0034] Among these, when used for integral skin foam such as soles, mold foaming, slab foaming, reaction injection molding, etc. are preferably used.

[0035] Specifically, examples of such methods include a method in which a polyol premix containing components other than polyisocyanate is prepared and then mixed with polyisocyanate to foam, and a method in which some or all of the components are introduced into the mixing head of a separate stirring mixer and foamed. In both methods, polyurethane foam can be produced by injecting the mixed liquid into a mold or into a conveyor having walls on the top, bottom, left, and right sides.

[0036] The method for producing a sole using the polyurethane foam is not particularly limited, but a polyurethane foam sole can be obtained by reacting raw material components or foaming TPU pellets in a mold of a predetermined shape, or by cutting or punching the polyurethane foam into a predetermined shape. The polyurethane foam may also be produced in the presence of an outsole, shank, upper material, etc., or a composite sole produced by printing, spinning, etc. may be produced as is.

[0037] <Properties of polyurethane foam> The polyurethane foam has low hardness from low to high temperatures and is excellent in resilience.

[0038] Furthermore, soles made from this material are flexible and have excellent cushioning and resilience regardless of environmental conditions such as temperature, and when used in shoes, they provide excellent comfort and safety and reduce energy loss during running, so it is preferable that they exhibit the following viscoelastic behavior.

[0039] The storage modulus E' of the polyurethane foam at a frequency of 10 Hz and 0 to 100°C is 3 × 10 6 Pa. Preferably, it is less than 5×10 5 Pa~3×10 6 The range of Pa is preferred, and 7×10 5 Pa ~ 2.5 × 10 6 Pa, and most preferably less than 1×10 6 Pa~2×106 The range is less than Pa.

[0040] In particular, the rate of change in storage modulus E' from 0 to 100°C is preferably 65% ​​or less, more preferably 50% or less, and most preferably in the range of 20 to 45%, in the above temperature range, because flexibility is less likely to change depending on the surrounding environment and safety is high. The rate of change in storage modulus E' from 0 to 100°C can usually be expressed as the ratio of storage modulus E' at 100°C to storage modulus E' at 0°C.

[0041] The storage modulus E' at a frequency of 10 Hz and 0 to 100°C is 3 × 10 6 If the temperature exceeds 100°C, the hardness of the urethane foam will be too high and it will be unable to be used due to its poor flexibility at that temperature. However, the storage modulus E' at a frequency of 10 Hz and 0 to 100°C is 3 x 10 6 If the modulus is less than 1 / 2 Pa, the polyurethane foam exhibits good flexibility even when used in low-temperature conditions such as in cold regions or when used on high-temperature roads, and is less dependent on the surrounding environment. When used as a sole, it exhibits good cushioning properties regardless of the surrounding environment, such as when used in low-temperature conditions such as in cold regions or when used on high-temperature roads, and when used in shoes, it provides flexibility, comfort, and cushioning regardless of the surrounding temperature, and excellent safety when running.

[0042] Furthermore, although not particularly limited, it has excellent heat resistance and is easy to handle, such as being resistant to settling during heat drying, so in applications where heat resistance is required, the storage modulus E' at a frequency of 10 Hz and 180°C is 2 × 10 5 Pa or more, and more preferably 5×10 5 Pa or more, most preferably 5×10 5 Pa~1×10 6 The range is Pa.

[0043] Although not particularly limited, the storage modulus E' of the polyurethane foam at a frequency of 10 Hz and 25°C is 2.8 × 10 6It is preferable that the storage modulus E' at a frequency of 10 Hz and 25°C is less than 5 × 10 5 Pa~2.8×10 6 Pa, more preferably 7×10 5 Pa~1.7×10 6 Pa, most preferably in the range of 1×10 6 Pa~1.7×10 6 The storage modulus E' at a frequency of 10 Hz and 25°C is 2.8 x 10 6 If the hardness is less than Pa, it is likely to become a polyurethane foam with low hardness and good flexibility under room temperature conditions, and when used as a sole, it has good flexibility and therefore excellent cushioning properties, and when used in sports shoes, it is likely to be comfortable and safe to wear, making it preferable.

[0044] The ratio (tan δ) of the loss modulus E" to the storage modulus E' of the polyurethane foam at a frequency of 10 Hz and 0 to 100°C is 0.15 or less. In particular, tan δ at a frequency of 10 Hz and 0 to 100°C is preferably in the range of 0.02 to 0.15, and more preferably 0.04 to 0.14. If the ratio (tan δ) of the loss modulus E" to the storage modulus E' at a frequency of 10 Hz and 0 to 100°C is 0.15 or less, the polyurethane foam will exhibit high rebound resilience regardless of the environment because little energy is converted into heat or the like during use regardless of the ambient temperature, will have good rebound properties when used as a sole regardless of the ambient temperature, and will have excellent running properties when used in shoes because energy loss during running can be suppressed regardless of the environment.

[0045] Furthermore, although not particularly limited, if the tan δ at a frequency of 10 Hz and 25°C is 0.10 or less, the conversion of energy into heat, etc., when used at room temperature is significantly reduced, resulting in significantly high rebound resilience at room temperature, where use is frequent, and good rebound properties when used as a sole. Furthermore, when used in sports shoes, the energy loss during running at room temperature, where use is frequent, can be significantly reduced, resulting in less fatigue and excellent running properties, and is therefore preferable, and in particular, a tan δ at 25°C in the range of 0.02 to 0.10 is preferred, more preferably in the range of 0.03 to 0.09, and most preferably in the range of 0.04 to 0.08.

[0046] Furthermore, although not particularly limited, tan δ at a frequency of 10 Hz and 100° C. is preferably 0.050 or less, and more preferably 0.045 or less, since this allows for a more significant reduction in energy loss when used on a high-temperature road surface.

[0047] The glass transition temperature of the polyurethane foam is not particularly limited, but is preferably in the range of −80° C. to −30° C., and more preferably in the range of −80° C. to −50° C. A glass transition temperature in the range of −80° C. to −30° C. is preferable because flexibility is easily maintained even at low temperatures, and when used as a sole, shoes that maintain cushioning properties even in cold climates and are therefore highly safe are likely to be produced.

[0048] In the present invention, the storage modulus E', tan δ, and glass transition temperature refer to values ​​measured using a dynamic viscoelasticity measuring device, Rheogel E-4000 manufactured by UBM, under conditions of a measurement temperature of -100°C to 200°C, a heating rate of 3°C / min, a frequency of 10 Hz, a constant strain of 0.04%, and tensile mode, using test specimens cut out so that a skin layer is present in the thickness direction. The temperature at which tan δ, which is the ratio of loss modulus E" to storage modulus E', reaches its peak value is evaluated as the glass transition temperature, and the value at 25°C refers to the value evaluated as the ratio (tan δ) of loss modulus E" to storage modulus E' at 25°C.

[0049] <Physical properties of polyurethane foam> The average cell diameter of polyurethane foam is not particularly limited, and varies depending on the foaming density and application, but is usually in the range of 20 to 200 μm. It is preferably in the range of 50 to 150 μm, and more preferably in the range of 70 to 130 μm. If it is in the above range, it is preferred because it is likely to exhibit good mechanical properties.

[0050] The cell structure of the polyurethane foam is not particularly limited, but it is preferable that it contains 50% or more closed cell structures (closed cell ratio), and more preferably, it contains 50 to 90% closed cell structures (closed cell ratio).

[0051] The core density of the polyurethane foam is preferably in the range of 100 to 800 g / L, more preferably in the range of 150 to 500 g / L. If the core density exceeds 800 g / L, the cost may be high and the foam may not be practically usable, whereas if the core density is less than 100 g / L, the foam may have poor impact resilience and the like.

[0052] The polyurethane foam preferably has a rebound resilience of 50% or more at 25° C., although this is not particularly limited. In particular, when the polyurethane foam is used for applications requiring high rebound properties, the rebound resilience at 25° C. is preferably 55% or more, more preferably 60% or more, and most preferably 63% or more.

[0053] The rebound resilience of the polyurethane foam at 0° C. is not particularly limited, but is preferably 40% or more, more preferably 45% or more. In particular, when used in cold climates, the rebound resilience at 0° C. is preferably 50% or more, more preferably 55% or more.

[0054] Furthermore, the difference between the resilience modulus at 25° C. and the resilience modulus at 0° C. (change in resilience modulus) is not particularly limited, but is preferably within 10%, more preferably within 5%.

[0055] The hardness of the polyurethane foam at 25°C is not particularly limited, but is preferably in the range of 27 to 55. When used for a midsole, the hardness is preferably in the range of 30 to 55, more preferably 35 to 45, and when used for an insole, the hardness is preferably in the range of 20 to 45, more preferably 25 to 40.

[0056] The hardness of the polyurethane foam at 0°C is not particularly limited, but is preferably in the range of 30 to 60. When used for a midsole, the hardness is preferably in the range of 35 to 60, more preferably 40 to 50, and when used for an insole, the hardness is preferably in the range of 30 to 45, more preferably 35 to 45.

[0057] The difference between the hardness at 25°C and the hardness at 0°C is not particularly limited, but is preferably within 10 in Asker C hardness, and more preferably within 5 in Asker C hardness.

[0058] In the present invention, density was measured in accordance with JISK7222, and hardness (Asker C, surface hardness with skin), tensile strength (No. 3 dumbbell), tensile elongation (No. 3 dumbbell), tear strength (B-type dumbbell), and rebound elasticity (Lupke method) were measured in accordance with JISK7312.

[0059] The rebound resilience and hardness at 0°C refer to the values ​​measured within 10 seconds after removing a sample stored in a thermostatic chamber whose temperature is adjusted to 0±1°C for 24 hours, using the same method as above for room temperature.

[0060] <Polyol structure> The polyol used in the polyurethane foam is not particularly limited, but is a compound having one or more hydroxyl groups per molecule at any position within the molecule, and examples thereof include polyether polyols such as polytetramethylene glycol and polyalkylene oxide, polyester polyols, and polycarbonate diols.

[0061] Among these, there are no particular limitations as long as the polyurethane foam contains an oxyethylene structure and an oxypropylene structure, but it is preferable to include a polyether polyol (A) containing an oxyethylene group and an oxypropylene group as the polyol, as this facilitates the production of the polyurethane foam. In particular, since flexibility at low temperatures is readily exhibited, it is preferable to use 10% by weight or more of such polyether polyol (A) in the polyol, more preferably 40% by weight or more of the polyol, and most preferably 55% by weight or more. By including 10% by weight or more of a polyether polyol (A) containing oxyethylene groups in addition to oxypropylene groups in the polyol, crystallization in the urethane foam is easily inhibited even when a crystalline polyol is used in combination, and flexibility at low temperatures is likely to be significantly improved, which is preferable.

[0062] Although not particularly limited, if the oxytetramethylene structure is too much, crystallization may occur, deteriorating low-temperature properties and reducing flexibility at low to room temperature, so the content of polytetramethylene glycol in the polyol is preferably 70% by weight or less, more preferably 50% by weight or less, and most preferably in the range of 5 to 40% by weight, which is likely to improve the rebound resilience while suppressing deterioration in flexibility.Although not particularly limited, the molecular weight of the polytetramethylene glycol used in combination is preferably in the range of 1,000 to 3,000.

[0063] The polyether polyol (A) is preferably, for example, an alkylene oxide adduct in which one or more active hydrogen-containing compounds R[-H]m are used and two or more three-membered ring alkylene oxides having 2 to 12 carbon atoms are added, and is preferably a polyalkylene oxide represented by the following general formula (1).

[0064] [ka]

[0065] [In the above general formula (1), R represents an active hydrogen-containing compound (R[-H] m ) by removing m active hydrogen atoms, Z is an alkylene group or cycloalkylene group having 2 to 12 carbon atoms, and A is an alkylene group having 3 carbon atoms. When there are multiple Z or A, they may be the same or different. m is 2 to 100, p is 0 or an integer of 1 to 500, q is an integer of 1 to 1000, and r is an integer of 1 to 500.] Active hydrogen-containing compounds (R[-H] mThe alkyl ester is not particularly limited as long as it has an active hydrogen group, and examples thereof include bifunctional diols such as water, propylene glycol, ethylene glycol, diethylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, tripropylene glycol, triethylene glycol, polyoxyalkylene diols such as Sannix PP-200, PP-400, PP-600, and PP-1000 manufactured by Sanyo Chemical Industries, Ltd., bisphenols such as bisphenol A, bisphenol F, and bisphenol AD, dihydrides such as catechol, resorcinol, and hydroquinone. Examples of the active hydrogen-containing compound include compounds having two active hydrogen groups, such as hydroxybenzenes, amines such as methylamine, ethylamine, propylamine, and butylamine; triols such as glycerin, trimethylolpropane, 1,2,6-hexanetriol, and trifunctional low molecular weight polyols such as Sannix GP-250, GP-400, GP-600, and GP-1000 manufactured by Sanyo Chemical Industries; tetraols such as pentaerythritol and diglycerin; hexol, ammonia, amines such as ethanolamine, diethanolamine, and triethanolamine; and compounds having three or more active hydrogens. m ) can be used alone or in combination of two or more selected from these.

[0066] Active hydrogen-containing compounds (R[-H] m The alkylene oxide to be added to (II) is not particularly limited as long as it is a compound having one or more epoxy rings in the molecule, and examples thereof include alkylene oxides having 2 to 12 carbon atoms such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide, and one or more alkylene oxides may be used.

[0067] Among these, one or more alkylene oxides including alkylene oxides having 2 to 3 carbon atoms, such as propylene oxide and ethylene oxide, which are easily available industrially, are preferred, and two alkylene oxides, propylene oxide and ethylene oxide, are more preferred.

[0068] ZO in the above general formula (1) preferably has a polyether structure derived from an alkylene oxide having 2 to 12 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide, or styrene oxide, because this tends to provide good moldability into a urethane foam. More preferred are polyether structures derived from one or more alkylene oxides selected from ethylene oxide and propylene oxide, and most preferred are polyether structures derived from one type of alkylene oxide selected from ethylene oxide and propylene oxide.

[0069] In the above general formula (1), p is 0 or an integer of 1 to 500, preferably p=0 or an integer of 1 to 100, and more preferably p=0.

[0070] As Z in the above general formula (1), for example, a structure represented by the following general formula (2) can be mentioned.

[0071] [ka]

[0072] [In the above general formula (2), R2, R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms, provided that the total number of carbon atoms of R2 to R5 does not exceed 10. Any two of R2 to R5 may combine to form a cycloalkyl group.] Furthermore, AO in the above general formula (1) is preferably a polyether structure derived from an alkylene oxide having 3 carbon atoms, such as propylene oxide, because this tends to provide good flexibility when made into a polyurethane foam.

[0073] Examples of A in the above general formula (1) include structures represented by the following formulas.

[0074] [ka]

[0075] In the above general formula (1), q is an integer of 1 to 1000, preferably q=an integer of 10 to 500, and more preferably q=an integer of 15 to 100.

[0076] In the general formula (1), r is 0 or an integer of 1 to 500. Since the composition is less likely to solidify at low temperatures and has excellent handleability, r is preferably 0 or an integer of 1 to 100, and more preferably r is 0 or an integer of 1 to 50.

[0077] The relationship between p, q, and r in the general formula (1) preferably satisfies p+q>r (where p+q is 10 to 1000, q is 10 to 1000, and r is 0 or 1 to 100), because this makes it difficult for the polyurethane to crystallize and facilitates the development of flexibility at low temperatures. More preferably, p+q>2r (where p+q is 15 to 300, q is 15 to 300, and r is 0 or 1 to 100) is satisfied, and most preferably, 10r>p+q>2r (where p+q is 30 to 150, q is 30 to 150, and r is 5 to 50) is satisfied.

[0078] The weight ratio of oxyethylene groups to oxypropylene groups in the polyether polyol (A) is not particularly limited, but is preferably in the range of 1:99 to 49:51, more preferably in the range of 5:95 to 35:65, and most preferably in the range of 10:90 to 25:75. This weight ratio of oxyethylene groups to oxypropylene groups can be determined from the integral ratio of 1H NMR measured by a conventional method.

[0079] The primary hydroxyl group ratio in the polyether polyol (A) is not particularly limited, but is preferably in the range of 40 to 99%, more preferably in the range of 60 to 95%, and most preferably in the range of 70 to 90%.

[0080] In particular, when a polyol other than the polyether polyol (A) is used in an amount of 30% by weight or more as the polyol, the primary ratio is preferably in the range of 75 to 90%.

[0081] The ratio of primary hydroxyl groups in polyether polyol A can be calculated from the integral ratio of 1H NMR measured by a conventional method after pretreating the polyether polyol A with trifluoroacetic anhydride or the like.

[0082] As the polyether polyol (A), a combination of a polyether polyol (A1) and a polyether polyol (A2) may be used. In this case, a preferred combination is one in which the polyether polyol (A1) is a diol where m=2, and the polyether polyol (A2) is a triol or tetraol where m=3 or 4.

[0083] Furthermore, when polyether polyol (A1) and polyether polyol (A2) are used in combination, it is more preferable that each of polyether polyol (A1) and polyether polyol (A2) has the above structure, but it is also preferable that the polyether polyol contained in a larger amount has the above structure in its molecular structure.

[0084] <Properties of polyol> The polyol used for the polyurethane foam is not particularly limited, but it is preferable to use polyether polyol A, which has a significantly low degree of unsaturation, because it is easy to obtain a polyurethane foam with significantly high impact resilience regardless of temperature conditions. When such a polyether polyol is not used as the polyol, it is preferable to use it as an isocyanate modifier and incorporate it into the urethane.

[0085] The degree of unsaturation of the polyether polyol (A) is preferably 0.010 meq / g or less, more preferably in the range of 0.0005 to 0.005 meq / g, and most preferably in the range of 0.001 to 0.003 meq / g.

[0086] When a combination of polyether polyol (A1) and polyether polyol (A2) is used as the polyether polyol (A), it is preferable that the degree of unsaturation of each is within the above range, but the polyether polyol contained in a larger amount can be suitably used as long as its degree of unsaturation is within the above range.

[0087] If the degree of unsaturation is within the above range, the amount of dangling chains and low-molecular-weight components derived from unsaturated structures and mono-ol components in the resulting polyurethane foam will be significantly reduced, making it easier to obtain a polyurethane foam of the present invention with a significantly low tan δ and high resilience, and soles and shoes using such a polyurethane foam will have significantly higher resilience and will likely result in sports shoes with less energy loss and less fatigue during use, which is preferable.

[0088] In the present invention, the "degree of unsaturation (meq / g)" of a polyol refers to the total amount of unsaturated groups contained per gram of polyol. This value is measured in accordance with the NMR method described in "Collaboration of Polymers, Vol. 50, No. 2, 121-126," with a scan count of 500 or more being preferred. Values ​​measured in accordance with the method specified in JIS K1557 6.7 may not be accurate due to impurities. The degree of unsaturation of a polyether polyol is an indicator of the amount of monools present in the polyether polyol. An increase in the degree of unsaturation can reduce the average number of functional groups in the polyether polyol. This can lead to termination reactions when used as a polyurethane raw material, resulting in a decrease in the molecular weight of the polyurethane and an increase in uncrosslinked low-molecular-weight components. Furthermore, the unsaturation can act as dangling chains in the polyurethane, increasing tan δ and reducing the impact resilience.

[0089] The number average molecular weight (M) calculated from the hydroxyl value of the polyol used in the polyurethane foam is not particularly limited, but it is preferable to use a polyether polyol (A) whose number average molecular weight (M) calculated from the hydroxyl value is 1500 to 30000, more preferably 1500 to 15000, and most preferably 2500 to 7500.

[0090] If the number average molecular weight (M) of the polyether polyol (A) is within the above range, the storage modulus of the resulting polyurethane foam at low temperatures tends to be low, and a polyurethane foam with excellent low-temperature properties is likely to be obtained, which is preferable. When a combination of polyether polyol (A1) and polyether polyol (A2) is used as the polyether polyol (A), it is preferable that the molecular weights of the respective components are within the above-mentioned ranges. However, the polyether polyol contained in a larger amount can be suitably used as long as its molecular weight is within the above-mentioned range.

[0091] In the present invention, the number average molecular weight (M) calculated from the hydroxyl value of the polyol refers to a value calculated using the following mathematical formula (1) based on the hydroxyl value (OHV, unit: mgKOH / g) of the polyol.

[0092] Number average molecular weight = (56100 / OHV) × number of hydroxyl groups per molecule (1) Here, "OHV" is a value measured in accordance with JIS K1557 6.4. Furthermore, "number of hydroxyl groups per molecule" refers to the number of active hydrogen atoms per molecule of the active hydrogen-containing compound, which is the initiator used as a raw material in producing each polyol. When the number of active hydrogen atoms of a commercially available initiator cannot be specified, the nominal functionality is used.

[0093] In the present invention, the polyether polyol (A) preferably used as the polyol is preferably a compound that is liquid and amorphous at room temperature. If the polyether polyol (A) is liquid and amorphous at room temperature, it tends to have excellent moldability, such as being easy to use without heating.

[0094] The glass transition temperature of the polyether polyol (A) is preferably −30° C. or lower, since this makes it easier to obtain a polyurethane foam that is easy to handle and has a low storage modulus at low temperatures.

[0095] The viscosity of the polyether polyol (A) used as the polyol at 25°C is not particularly limited and may be appropriately selected depending on the application, but is preferably in the range of 0.1 to 2000 Pa·s (25°C), more preferably 0.2 to 200 Pa·s (25°C). If the viscosity of the polyalkylene oxide (A) is in the range of 0.1 to 2000 Pa·s (25°C), molding is easy, and the physical properties of the resulting polyurethane foam tend to be stable.

[0096] In the present invention, "viscosity" at 25°C refers to a value measured using a cone-plate rotational viscometer in accordance with JIS K1557-5, Section 6.2.3. Specifically, it refers to viscosity at a shear rate of 0.1 (1 / s). However, if the viscosity is outside the measurement range, the shear rate range may be adjusted to fall within the measurement range, within a range of 0.01 to 10 (1 / s).

[0097] The molecular weight distribution of the polyether polyol (A) used as the polyol, as determined by gel permeation chromatography (GPC) using polystyrene as a standard, is preferably 1.039 or less, more preferably in the range of 1.003 to 1.039, even more preferably in the range of 1.005 to 1.029, and most preferably in the range of 1.006 to 1.019, since the crosslinking of the resulting polyurethane foam becomes uniform and the foam tends to exhibit significantly high impact resilience.

[0098] Furthermore, when a difunctional polyether polyol (A1) and a tri- or higher functional polyether polyol (A2) are used in combination as the polyether polyol (A), it is more preferable that the molecular weight distributions (Mw / Mn) of the polyether polyol (A1) and the polyether polyol (A2), determined by gel permeation chromatography (GPC) using polystyrene as the standard substance, are each within the above-mentioned range. However, the polyether polyol contained in a larger amount can be suitably used as long as its molecular weight distribution (Mw / Mn) is within the above-mentioned range. In particular, when a polyether polyol having a molecular weight distribution (Mw / Mn) of more than 1.039 or a degree of unsaturation of more than 0.010 meq / g is used as the polyether polyol (A), the molecular weight between crosslinking points in the resulting polyurethane foam becomes non-uniform, making it difficult to obtain a flexible, highly resilient polyurethane foam. Therefore, the content of such polyether polyol (A) in the polyol is preferably less than 30% by weight, more preferably less than 10% by weight.

[0099] The molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) using polystyrene as a standard substance is preferably a molecular weight distribution measured and analyzed under conditions in which four separation columns packed with packing material having a particle size of 3 μm are connected in series, a resistance tube is connected to the reference side, and tetrahydrofuran is used as the developing solvent, and is calculated using a third-order approximation calibration curve using standard polystyrene.

[0100] The method for producing the polyether polyol (A) used as the polyol is not particularly limited, but it is preferable to produce it by ring-opening polymerization of alkylene oxide in the presence of an active hydrogen-containing compound, a base catalyst, and a Lewis acid at as low a temperature as possible, as this makes it easier to obtain a urethane foam with significantly high impact resilience. It is more preferable to produce it by carrying out the reaction under the above conditions in a catalyst system that reduces impurities that may be the cause of by-products and produces by-products with low boiling points, and most preferably to produce it by removing the by-products sufficiently under reduced pressure and then adsorbing them onto a solid, in addition to the above conditions. <Polyisocyanate> The polyisocyanate used in the polyurethane foam is not particularly limited, but is a compound having one or more isocyanate groups per molecule at any position within the molecule, and specific examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and 1,6-hexamethylene diisocyanate. , 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, pentamethylene diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, isocyanate-containing prepolymers obtained by reacting these with polyols, and mixtures of two or more of these. Furthermore, modified products of these isocyanates (for example, modified products containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, an isocyanurate group, an amide group, an imide group, a uretonimine group, a uretdione group, or an oxazolidone group) and condensates (sometimes referred to as polynuclear compounds) of polymethylene polyphenylene polyisocyanate (polymeric MDI) are also included.

[0101] Among these, one or more modified isocyanates selected from the group consisting of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and partially carbodiimide-modified isocyanates thereof are preferred, as these tend to result in a lower tan δ at room temperature and higher impact resilience at room temperature, and more preferred are urethane-modified isocyanates of one or more polyisocyanates selected from the group consisting of 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and partially carbodiimide-modified isocyanates thereof with polyalkylene oxide and / or polytetramethylene glycol.

[0102] Among these, most preferred are 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and a urethane-modified product of one or more polyisocyanates selected from the group consisting of these with a polyether polyol having an unsaturation degree of 0.010 meq / g or less and containing an oxypropylene group and / or polytetramethylene glycol having a number average molecular weight of 1500 to 3500, the modified isocyanate having an isocyanate group content of 7 to 25% by weight. Even when a polyether polyol A containing an oxyethylene group and an oxypropylene group is not used as the polyol, using such a polyether polyol A as an isocyanate modifier is preferred because the polyurethane foam can be easily obtained.

[0103] The amount of polyisocyanate used in the polyurethane foam is not particularly limited as long as it is within the scope of the present invention; however, if the amount is too large, the elastic modulus at low temperatures will be high, making it difficult to obtain a polyurethane foam that is flexible regardless of temperature. Therefore, the amount is preferably in the range of 1 to 200 parts by weight, more preferably 10 to 100 parts by weight, and most preferably 30 to 70 parts by weight, per 100 parts by weight of polyol.

[0104] The addition ratio of the polyisocyanate used in the polyurethane foam is not particularly limited, but is preferably in a range such that the ratio of the total number of NCO groups in the polyisocyanate (B) to the total number of OH groups in the active hydrogen-containing compound including the polyol (referred to as the NCO / OH ratio) is 0.5 to 1.5 (molar ratio), and more preferably 0.6 to 1.1 (molar ratio). <Foaming agent> The blowing agent used as the polyurethane foam raw material is not particularly limited, and known commercially available physical blowing agents and / or chemical blowing agents can be used. Examples of physical blowing agents include low-boiling halogenated hydrocarbons such as chlorofluorocarbons, hydrochlorofluoroolefins, hydrochlorofluorocarbons, hydrofluoroolefins, hydrofluorocarbons, perfluorocarbons, and methylene chloride; hydrocarbons such as acetone, methyl formate, hexane, isopentane, pentane, and cyclopentane; and gases or cryogenic liquids such as air, nitrogen, and carbon dioxide. Examples of chemical blowing agents include water, organic acids, inorganic acids such as boric acid, alkali carbonates, cyclic carbonates, dialkyl carbonates, and azo compounds that react with polyurethane raw materials or decompose under heat or other conditions to generate gas, with water being preferred.

[0105] Although it depends on the type and formulation of the catalyst, when only water is used as the blowing agent, it is preferably in the range of 0.1 to 5 parts by weight, more preferably 0.3 to 2.5 parts by weight, per 100 parts by weight of polyol.

[0106] <Additives> The polyurethane foam may contain additives, which are not particularly limited, but specific examples thereof include foam stabilizers, viscosity modifiers such as viscosity reducers and thickeners, urethane catalysts, fillers, flame retardants, antioxidants, UV absorbers, light stabilizers, antifungal agents, antibacterial agents, VOC catchers, and mold release agents. Among these, it is preferable to use a foam stabilizer and a thickener, since these can easily suppress the reduction of the cell diameter of the polyurethane foam and can easily exhibit high mechanical properties.

[0107] The foam stabilizer is not particularly limited, and examples thereof include known surfactants such as organic silicone surfactants, including nonionic surfactants such as organic siloxane-polyoxyalkylene copolymers and silicone-grease copolymers. The amount of foam stabilizer added to the polyurethane foam is preferably in the range of 100 to 50,000 ppm.

[0108] The thickener is not particularly limited, and known thickeners and rheology control agents can be used, including fine powder thickeners such as carbon black and finely powdered silica, hydrogenated castor oil wax and fatty acid amide wax, and urea-based rheology control agents such as BYK-410, BYK-415, BYK-420, and BYK-430 manufactured by BYK-Chemie.

[0109] Examples of viscosity reducers include phthalates such as dibutyl phthalate, diheptyl phthalate, di(2-ethylhexyl) phthalate, dioctyl phthalate, dioctyl adipate, dioctyl sebacate, dibutyl sebacate, isodecyl succinate, tricresyl phosphate, tributyl phosphate, epoxidized soybean oil, and benzyl epoxy stearate, as well as non-aromatic dibasic acid esters, aliphatic esters, esters of polyalkylene glycols, trimellitic acid esters, chlorinated paraffins, hydrocarbon oils, process oils, polyethers, epoxy plasticizers, and polyester plasticizers. The content of the viscosity reducer is not particularly limited, but is preferably less than 25% by weight of the polyurethane foam.

[0110] The filler is not particularly limited, and any filler can be selected and used, for example, inorganic fillers, organic fillers, fibrous fillers, and the like.

[0111] Specific examples of fillers include fumed silica, precipitated silica, crystalline silica, fused silica, dolomite, silicic anhydride, and hydrous silicic acid; calcium carbonates such as fatty acid-treated calcium carbonate, heavy calcium carbonate, and colloidal calcium carbonate; pigments such as carbon black, magnesium carbonate, magnesium hydroxide, iron oxide, zinc oxide, diatomaceous earth, calcined clay, clay, talc, titanium oxide, barium sulfate, kaolin, zeolite, bentonite, organic bentonite, aluminum, and flint powder; shirasu balloons, glass microballoons, synthetic resin powders such as phenolic resin, vinylidene chloride resin, polyvinyl chloride, polymethyl methacrylate, and polystyrene; asbestos, glass fiber, and glass filament. These fillers can be used alone or in combination, and may be surface-treated with an appropriate surface treatment agent. The filler content is not particularly limited, but is preferably less than 25% by weight of the polyurethane foam.

[0112] The antioxidant is not particularly limited, and examples thereof include compounds that have the effect of suppressing oxidation of polymer chains, such as thioether-based compounds, phosphorus-based antioxidants, and hindered phenol-based compounds, and examples of such compounds include Irganox manufactured by Ciba Corporation and Adekastab manufactured by Adeka Corporation.

[0113] Among these, hindered phenol-based antioxidants are preferred as antioxidants, and it is particularly preferred to use one or more antioxidants selected from 2,6-di-t-butyl-4-methylphenol (BHT), IRGANOX-1010, IRGANOX-1024, IRGANOX-1035, IRGANOX-1076, and IRGANOX-1081 manufactured by Ciba Japan, as these are more likely to provide antioxidant properties to urethane.

[0114] The light stabilizer is not particularly limited, but examples thereof include compounds that have the effect of imparting light resistance, weather resistance, etc., such as ultraviolet absorbers such as benzotriazole-based compounds, triazine-based light stabilizers, benzophenone-based light stabilizers, and benzoate-based compounds, and hindered amine-based light stabilizers, and examples of such products include Tinuvin manufactured by Ciba Japan.

[0115] Among them, it is preferable to use one or more types of light stabilizers selected from Tinuvin 234, Tinuvin 144, Tinuvin C353, and Tinuvin B75. These antioxidants and light stabilizers can also be used in combination.

[0116] Examples of urethanization catalysts include organolead compounds, organotin compounds, bismuth compounds such as bismuth octoate, tertiary amines, and quaternary ammonium salts, and preferably, one or more catalysts selected from organotin compounds and tertiary amine catalysts.

[0117] Examples of tertiary amines include triethylenediamine, dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"',N"'-hexamethyltriethylenetetramine, bis(dimethylaminoethyl)ether, 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, N-dimethylaminoethyl-N'-methylpiperazine, N,N,N',N'-tetramethylhexamethylenediamine, 1,2-dimethylimidazole, and N,N-dimethyl and alkanolamines such as N-(3-dimethylaminopropyl)-N,N-diisopropanolamine, N-(2-hydroxyethyl)-N'-methylpiperazine, N,N-dimethylaminohexanol, and 5-dimethylamino-3-methyl-1-pentanol.

[0118] Examples of organotin compounds include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctoate, and tin 2-ethylhexanoate. If the amount of these urethane catalysts added is too small, foaming delay may occur, resulting in reduced productivity, while if it is too large, foaming may become uneven and the foam properties may become unstable. Therefore, the amount of tertiary amines added to the polyurethane foam is preferably in the range of 0.01 to 15% by weight, and the amount of organotin compounds added is preferably in the range of 0.05 to 1% by weight. <Applications of polyurethane foam> The polyurethane foam according to one embodiment of the present invention can be used in a variety of applications for which flexible polyurethane foams, semi-rigid polyurethane foams, and rigid polyurethane foams are generally used.

[0119] Although not particularly limited, examples of applications include heat insulation materials and structural materials in the fields of architecture and civil engineering; heat insulation materials for freezers, refrigerators, freezer showcases, etc. in the field of electrical equipment; heat insulation materials for LPG and LNG tankers and pipelines in the field of plants and ships; heat insulation materials for refrigerator cabinets and refrigerated vehicles in the field of vehicles, instrument panels, etc.; but the material is preferably used in applications requiring cushioning and rebound resilience, such as bedding, bicycle saddles, motorcycle seats, automobile seats, cushioning materials, sound absorbing materials, vibration damping materials, flooring materials, sports surfaces, racing tracks, floor covering materials, balls, etc.; steering wheels, headrests, gear lever knobs, armrests, the inside of helmets, shock-absorbing parts for protectors, vehicle shock-absorbing materials; shoe materials such as high heels, geta sandals, and multi-purpose shoes; soles such as midsoles, insoles, and outsoles of sports shoes such as tennis shoes, basketball shoes, running shoes, walking shoes, and sports sandals; and shanks, as well as other shoe materials.

[0120] In particular, since it has high flexibility and resilience from low to room temperature and high temperatures, and its physical properties are unlikely to change depending on the environment, it is suitable for use in shoe soles such as midsoles and insoles, and is suitable for use in the midsoles and insoles of sports shoes such as basketball shoes, running shoes, walking shoes, and sports sandals.

[0121] Shoe soles using the above-mentioned polyurethane foam are not particularly limited, but examples include sole-shaped urethane foam obtained by foaming in a mold of a predetermined shape, or by cutting or punching polyurethane foam into a predetermined shape, as well as sole-shaped urethane foam composited with fabric, printing, or other cushioning materials such as EVA, and sole-shaped urethane foam composited with outsole materials such as rubber, shank, upper materials, etc. These have high flexibility and rebound resilience from low to high temperatures and excellent cushioning properties, making them suitable for use as components of shoes.

[0122] The sports shoes according to one embodiment of the present invention are not particularly limited, and examples thereof include sports shoes constructed using the above polyurethane foam as part or all of the sports shoe material.

[0123] Preferred examples include sports shoes comprising at least an outsole, an insole, and a midsole, with the midsole made of a molded polyurethane foam, and sports shoes comprising at least an outsole, an insole, and a midsole, with the insole made of a molded polyurethane foam, and preferably comprising an upper material, a shank, a heel counter, shoelaces, a gel cushioning material, and adhesive components such as a urethane adhesive as necessary.

[0124] More preferably, the sports shoes have a midsole bonded to the outsole with an adhesive or by spinning, an insole constructed on top of that, a shank in the center of the outsole, the midsole and upper material bonded to the outsole with an adhesive or by spinning, and the upper material and heel counter are constructed, and it is preferable that the insole and / or midsole contain the above-mentioned polyurethane foam.

[0125] In particular, it is preferable that the sports shoes have any of the above configurations and contain 50% by weight or more of the polyurethane foam in the insole and / or midsole, and that 20% by weight or more of the weight of the sports shoes is made up of the polyurethane foam.

[0126] It is preferable that the outsole material used in the sports shoes is rubber, and the shank and adhesive are made of urethane. [Example]

[0127] The present invention will be explained in more detail below using examples, but the present invention should not be construed as being limited to the following examples as long as the gist of the invention is not exceeded. The raw materials and evaluation methods used in the following examples and comparative examples are as follows. (raw materials) <Polyol> The properties of the polyols used in the examples and comparative examples are shown in Table 1.

[0128] [Table 1]

[0129] Polyols (A1) to (A3): Difunctional polyalkylene oxides obtained by thoroughly dehydrating and removing the solvent using a combination of an imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum, followed by block copolymerization of sufficiently dehydrated propylene oxide and ethylene oxide in this order with a difunctional polyoxypropylene glycol having a molecular weight of 200, followed by removal of the catalyst by a conventional method, and containing the antioxidant BHT.

[0130] Polyol (A4): Commercially available polytetramethylene glycol (PTMG-1000 manufactured by Mitsubishi Chemical Corporation).

[0131] Polyol (A5): Commercially available polytetramethylene glycol (PTMG-3000 manufactured by Mitsubishi Chemical Corporation).

[0132] Polyol (A6): A polyalkylene oxide produced by adding propylene oxide and ethylene oxide in a conventional manner using a potassium hydroxide catalyst.

[0133] Polyol (A7): A bifunctional polyalkylene oxide obtained by thoroughly dehydrating and removing the solvent using a combination of an imino group-containing phosphazenium salt (IPZ) catalyst and triisopropoxyaluminum, polymerizing only the propylene oxide that has been sufficiently dehydrated to a bifunctional polyoxypropylene glycol with a molecular weight of 200, removing the catalyst using a conventional method, and incorporating the antioxidant BHT.

[0134] The above polyols were heated and vacuum dehydrated before use. For non-commercially available products, the catalyst was removed by a conventional method before use.

[0135] Polyol (A1) had a significantly lower degree of unsaturation and a narrower molecular weight distribution than polyol (A6). Polyols (A2) and (A3) also had a lower degree of unsaturation and a narrower molecular weight distribution.

[0136] <Polyisocyanate> Polyisocyanate (C1): A modified isocyanate obtained by adding 20% ​​by weight of PTMG to a partially carbodiimide-modified isocyanate of 4,4'-diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name Millionate MTL).

[0137] Polyisocyanate (C2): 4,4'-diphenylmethane diisocyanate (4,4'-MDI, manufactured by Tosoh Corporation, trade name Millionate MT) These were used as is without purification.

[0138] <Additives> Urethane catalyst: 1-isobutyl-2-methylimidazole (manufactured by Evonik, trade name DABCO NCIM) 1,4-BD: 1,4-butanediol (Wako Pure Chemical Industries, Ltd.) Silicon foam stabilizer: A commercially available silicone foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., product name SRX-280A) The above commercially available product was used as is. Ion-exchanged water was used as the foaming agent. (Polyol evaluation method) <Hydroxyl value, molecular weight> The hydroxyl value (OHV) of the polyol was measured according to the method of JIS-K1557-1. Also, the number average molecular weight of the polyol is a value calculated using the above formula (1) based on the hydroxyl value of the polyol.

[0139] <Degree of unsaturation> It was measured according to the method described in Polymer Transactions 1993, 50, 2, 121-126 using a nuclear magnetic resonance apparatus (NMR) and confirmed by the method of JIS K1557 6.7.

[0140] <Molecular weight distribution (Mw / Mn)> 10 mg of polyol and 10 ml of THF were added to a sample bottle, dissolved by standing overnight, and the sample was obtained by filtering with a PTFE cartridge filter (0.5 μm). As a detector, an RI detector RI8020, and as measurement columns, a total of 4 columns of Tosoh Tskgel SuperH4000×2 columns and Tskgel SuperH3000×2 columns filled with a packing material with a particle size of 3 μm were connected in series, and 5 resistance tubes were connected on the reference side. A special grade tetrahydrofuran containing a BHT stabilizer manufactured by Wako Pure Chemical Industries, Ltd. was used as the developing solvent, and analysis was performed under the conditions of a flow rate of 0.6 ml / min on the separation column side, a flow rate of 0.15 ml / min on the reference side, and a column temperature of 40 °C. Using a third-order approximation curve of 8 standard polystyrenes manufactured by Tosoh with known molecular weights as a calibration curve, the molecular weight distribution (Mw / Mn) was analyzed. The measuring device used was HLC-8320GPC manufactured by Tosoh, and the analysis used HLC-8320GPC-ECOSEC-WorkStation manufactured by Tosoh.

[0141] <EO content (wt%)> Using a nuclear magnetic resonance apparatus (NMR), 1H NMR was measured using deuterated chloroform containing tetramethylsilane as a heavy solvent. The ethylene oxide content in the polyol was calculated from the integral value in the range of 0.8 to 1.5 ppm (propylene oxide chain) and the integral value in the range of 3.2 to 3.9 ppm (propylene oxide chain and ethylene oxide chain).

[0142] <Primary ratio of OH groups> Using a nuclear magnetic resonance (NMR) spectrometer, 1H NMR of the sample treated with trifluoroacetic anhydride was measured using tetramethylsilane-containing deuterated chloroform as the deuterated solvent. The ratio of primary OH groups in the polyol was calculated from the integral value around 4.3 ppm (methylene bonded with esters derived from primary OH groups) and the integral value around 5.2 ppm (methine bonded with esters derived from secondary OH groups) of the sample treated with trifluoroacetic anhydride. (Evaluation of polyurethane foam properties) <Dynamic viscoelasticity> The storage modulus E', tan δ, and glass transition temperature were measured using a dynamic viscoelasticity measuring device, Rheogel E-4000, manufactured by UBM, under the following conditions: a measurement temperature of -100°C to 200°C, a heating rate of 3°C / min, a frequency of 10 Hz, a constant strain of 0.04%, and tensile mode conditions. Test specimens were cut out so that they had a skin layer in the thickness direction. The temperature at which tan δ, which is the ratio of the loss modulus E" to the storage modulus E', reaches its peak value was evaluated as the glass transition temperature, and the value at each temperature, for example 25°C, was evaluated as the ratio (tan δ) of the loss modulus E" to the storage modulus E' at 25°C.

[0143] The storage modulus is 3×10 at any temperature in the range of 0℃ to 100℃. 6 If the resistance is less than Pa, the flexibility is high in the temperature range from low to high and the cushioning properties are remarkably good, and therefore it is judged as ◯ (pass).

[0144] In particular, if the rate of change in storage modulus E' between 0 and 100°C was 65% or less, it was judged to be acceptable because flexibility is less likely to change depending on the surrounding environment and safety is high. The rate of change in storage modulus within the above range was determined by the value of (maximum value - minimum value) / maximum value x 100.

[0145] Storage modulus at 25°C is 2.8 x 10 6 If the resistance is less than 100 Pa, the flexibility is particularly high at room temperature where the material is frequently used, and the cushioning properties are remarkably good, and therefore the material is judged to be acceptable.

[0146] In addition, the storage modulus E' at 180°C is 2×10 5If the resistance was 0.05 Pa or higher, it was judged to be acceptable (◯) since it was expected to have heat resistance during drying, etc.

[0147] If tan δ is 0.15 or less at any temperature in the range of 0°C to 100°C, it is expected to have little energy loss and high rebound resilience in the low to high temperature usage temperature range, so it is considered to pass.If tan δ exceeds 0.15, it will have large energy loss depending on the usage environment, making it difficult to use over a wide range of temperatures, so it is considered to fail.

[0148] Furthermore, if the tan δ at 25 is 0.10 or less, it is expected that the energy loss will be significantly less and that high resilience will be achieved at room temperature, where use is most frequent, and it is therefore judged to pass. However, if it exceeds 0.10, it will not exhibit any outstanding characteristics, particularly at room temperature, where use is most frequent, and will be difficult to use, so it is judged to fail.

[0149] <form cell> The foam cells were observed with an optical microscope to determine the bubble shape and the average bubble diameter. The closed cell ratio was calculated from the ratio of the apparent volume of a 5mm thick strip of foam measured with an AsOne NTK-01 digital volume meter.

[0150] <Urethane composition> The polyurethane foam was subjected to alkaline decomposition, and the composition of the urethane component was calculated by analyzing each fraction. The unsaturated group content, oxypropylene structure, oxyethylene structure, and oxytetramethylene structure were calculated from the integral ratios of 1H NMR and 13C NMR.

[0151] In addition, additives were extracted from the polyurethane foam using DMF, and the content of each component and the GPC molecular weight of the polyurethane foam were determined.

[0152] The gel fraction of the urethane foam was determined by adding 0.5 g of urethane foam to 100 ml of ethyl acetate and leaving it to stand for 7 days, and then determining the proportion (%) of the insoluble matter that remained undissolved. (Evaluation of the physical properties of polyurethane foam) In the present invention, density was measured in accordance with JISK7222, and hardness (Asker C, surface hardness with skin), tensile strength (No. 3 dumbbell), tensile elongation (No. 3 dumbbell), tear strength (B-type dumbbell), and rebound elasticity (Lupke method) were measured in accordance with JISK7312.

[0153] The rebound resilience and hardness at 0°C refer to the values ​​measured within 10 seconds after removing a sample stored in a thermostatic chamber whose temperature is adjusted to 0±1°C for 24 hours, using the same method as above for room temperature. (Polyurethane foam manufacturing) The raw material compositions of the foams produced in the Examples and Comparative Examples are shown in Table 3, the storage moduli E' and tan δ of the resulting foams at each temperature are shown in Table 4, and the physical properties of the foams are shown in Table 5.

[0154] Table 5 shows the calculated values ​​calculated from the raw material costs of the urethane component and auxiliary material components in the resulting polyurethane foam.

[0155] [Table 2]

[0156] [Table 3]

[0157] [Table 4]

[0158] [Table 5]

[0159] Example 1 A polyol premix was prepared by uniformly mixing the components excluding the isocyanate using a tabletop disper in the proportions shown in Table 2. The isocyanate component and the polyol premix, which had been adjusted to 45°C, were mixed and stirred using a tabletop mixer at a rotation speed of 7000 rpm.

[0160] The mixture was heated to 60°C, a release agent was applied, and the mixture was poured into a dry 300mm x 300mm x 5mm metal mold, which was then covered and allowed to cure for 7 minutes. After curing, the mold was removed and a urethane foam test piece (hereafter referred to as TP) was obtained. The urethane structure, urethane properties, and physical properties of the resulting TP were evaluated.

[0161] The polyurethane foam obtained had a low storage modulus in the range of 0°C to 100°C, and good cushioning properties over a wide temperature range. However, because its tan δ was low and its energy loss was small over a wide temperature range, it was expected to have high resilience over a wide temperature range. Furthermore, because its tan δ at 25°C was significantly low, its energy loss was characteristically small at room temperature, where it is frequently used. Furthermore, its storage modulus at 180°C was high, and it had high heat resistance.

[0162] The urethane foam had a resilience modulus of 60% or higher at both 0°C and 25°C, demonstrating significantly high resilience at both low and room temperatures. Furthermore, the Asker C hardness at both 0°C and 25°C was 50 or lower, demonstrating low hardness at both low and room temperatures, and the change in hardness was small.

[0163] The polyurethane foam of this example had a molecular weight of 50,000 or more, a gel fraction of less than 40%, and contained oxyethylene and oxypropylene structures in the urethane component, with significantly less unsaturated structures.

[0164] Example 2 Using the same method as in Example 1, urethane foam test pieces (hereinafter referred to as TP) were prepared with the formulation shown in Table 2, and the urethane structure, urethane properties, and physical properties were evaluated.

[0165] The resulting polyurethane foam had a tan δ of 0.10 at 25°C, which was higher than in Examples 1 and 3 to 8. However, in addition to having a lower tan δ than the foam of Comparative Example 3, the foam also had a significantly lower storage modulus and significantly better flexibility, making it suitable for applications where flexibility is particularly required in addition to rebound resilience.

[0166] Although the storage modulus is low in the range of 0°C to 100°C and cushioning is good over a wide range of temperatures, the tan δ is low and energy loss is small over a wide range of temperatures, so high rebound resilience can be expected over a wide range of temperatures. Furthermore, because the tan δ at 25°C is low, energy loss is characteristically small at room temperature, which is the temperature at which the material is frequently used. Furthermore, the storage modulus is high at 180°C and heat resistance is high.

[0167] The impact resilience of the urethane foam was 50% or more at both 0°C and 25°C, demonstrating high impact resilience at both low and room temperatures. Furthermore, the Asker C hardness at both 0°C and 25°C was 36 or less, demonstrating significantly low hardness at both low and room temperatures, and the change in hardness was significantly small.

[0168] The polyurethane foam of this example had a molecular weight of 50,000 or more, a gel fraction of less than 40%, and contained oxyethylene and oxypropylene structures in the urethane component, with significantly less unsaturated structures.

[0169] Examples 3 to 9 Using the same method as in Example 1, urethane foam test pieces (hereinafter referred to as TP) were prepared with the formulation shown in Table 2, and the urethane structure, urethane properties, and physical properties were evaluated.

[0170] The polyurethane foam obtained had a low storage modulus in the range of 0°C to 100°C, and good cushioning properties over a wide temperature range. However, because its tan δ was low and its energy loss was small over a wide temperature range, it was expected to have high resilience over a wide temperature range. Furthermore, because its tan δ at 25°C was significantly low, its energy loss was characteristically small at room temperature, where it is frequently used. Furthermore, its storage modulus at 180°C was high, and it had high heat resistance.

[0171] The impact resilience of the urethane foam was 50% or more at both 0°C and 25°C, demonstrating high impact resilience at both low and room temperatures. Furthermore, the Asker C hardness was 50 or less at both 0°C and 25°C, demonstrating low hardness at both low and room temperatures, and the change in hardness was small.

[0172] The polyurethane foams obtained in Examples 1 to 9 all had a uniform cell structure with an average cell diameter of 50 to 130 μm and a closed cell structure of 50 to 90%. The potassium content of the polyurethane foams obtained in Examples 1 to 9 was less than 50 ppm.

[0173] Comparative Example 1 Polyurethane elastomer (TPU) pellets prepared in advance according to the formulation in Table 2 were foamed in a heated mold using a physical foaming agent to prepare polyurethane foam test pieces.

[0174] The resulting polyurethane foam had a high tan δ of 0.19 at 0°C and a storage modulus of 3.3 × 10 6 However, because it exhibits high elasticity and a low tensile strength, it is difficult to use at low temperatures and does not have wide temperature characteristics.

[0175] Furthermore, the storage modulus at 180°C was significantly low, and the heat resistance was low.

[0176] The urethane foam of this comparative example did not contain an oxyethylene or oxypropylene structure in the urethane component, and instead contained a large amount of polyoxytetramethylene structure. Therefore, it had a high storage modulus at low to room temperature and poor flexibility. Its Asker C hardness at both 0°C and 25°C exceeded 50, and its hardness varied greatly, making it difficult to use depending on the environment. It also had a large change in rebound resilience, making its properties susceptible to change depending on the usage environment. Furthermore, the polyurethane foam had a low molecular weight and a non-uniform, fine cell structure, meaning its mechanical properties were not as promising. The closed cell ratio of the foam exceeded 90%.

[0177] Comparative Example 2 Test pieces of urethane foam were prepared using the formulation shown in Table 2 in the same manner as in Example 1, and the urethane structure, urethane properties, and physical properties were evaluated.

[0178] The resulting polyurethane foam had a good tan δ at 0°C and 25°C, but it did not have an oxyethylene or oxypropylene structure in the urethane component, and the storage modulus at low temperatures was significantly high, presumably due to crystallization of the polyoxytetramethylene moiety. As a result, the foam became hard at low temperatures, and cushioning properties could not be expected, making it difficult to use. In addition, the rate of change in storage modulus between 0°C and 25°C was high, and the material did not have wide temperature characteristics.

[0179] The urethane foam had good impact resilience at 0°C and 25°C, but its Asker C hardness exceeded 50. This meant that it had poor flexibility from low to room temperature and its hardness varied greatly, making it difficult to use depending on the environment. The foam's closed cell ratio also exceeded 90%.

[0180] Comparative Example 3 Using the same method as in Example 1, test pieces of urethane foam containing a large amount of unsaturated structures were prepared using a formulation containing a polyether polyol with a high unsaturated group content as shown in Table 2, and the urethane structure, urethane properties, and physical properties were evaluated.

[0181] The polyurethane foam of this comparative example has an oxyethylene structure and an oxypropylene structure in the urethane component, but the resulting polyurethane foam had a high tan δ value at 25°C, a tacky feel, and an insufficient rebound resilience of less than 50%, making it difficult to use.

[0182] The polyurethane foam of this comparative example contained many unsaturated structures and had a low molecular weight. The cells were small, less than 50 μm, so the foam could not be expected to have good mechanical properties.

[0183] Comparative Example 4 Using the same method as in Example 1, test pieces of urethane foam not containing an oxyethylene structure were prepared using the formulations shown in Table 2, including polyether polyol not having an oxyethylene group and polytetramethylene glycol, and the urethane structure, urethane properties, and physical properties were evaluated.

[0184] The polyurethane foam of this comparative example had a non-uniform, elongated cell structure, a low molecular weight of less than 50,000 of soluble components, a closed cell ratio of less than 50%, and a highly interconnected urethane foam that was brittle and dented when pressed with a finger.

[0185] The resulting polyurethane foam had a high tan δ value at 25°C and a storage modulus of 5.5×10 6 It showed high elasticity of 100 Pa, making it difficult to use at low temperatures and lacking wide temperature characteristics. In addition, the urethane properties were tacky and brittle, resulting in a significantly low impact resilience of 25, making it difficult to use.

[0186] Comparative Example 5 Commercially available EVA pellets were foamed in a heated mold using a physical foaming agent to prepare EVA foam test pieces.

[0187] The EVA foam of this comparative example had a significantly high storage modulus at low to normal temperatures, and was not expected to provide cushioning properties in the temperature range in which it was used.The tan δ at 25°C was as high as 0.19, resulting in a foam with a large energy loss.

[0188] Furthermore, the storage modulus at 180°C was significantly low, and the heat resistance was low.

[0189] The EVA foam had low resilience at 0°C and 25°C, and its Asker C hardness exceeded 50. This meant that it had poor flexibility from low to room temperature and its hardness changed significantly, making it difficult to use depending on the environment.

Claims

1. A composition comprising an oxyethylene structure and an oxypropylene structure derived from a bifunctional polyether polyol and an oxytetramethylene structure derived from polytetramethylene glycol, The content of the oxytetramethylene structure is in the range of 5 to 45% by weight, the content of unsaturated groups in the polyol fraction calculated by Colish decomposition is less than 0.08% by weight in the polyurethane foam; At a frequency of 10 Hz and in the range of 0 to 100°C, the storage modulus is 3 x 10 ６ A polyurethane foam having a modulus of elasticity (E") of less than 100 Pa and a ratio (tan δ) of loss modulus E" to storage modulus E' of 0.15 or less.

2. The content of the oxypropylene structure is in the range of 20 to 60% by weight, 2. The polyurethane foam according to claim 1, wherein the content of the oxyethylene structure is in the range of 5 to 20% by weight.

3. A polyurethane foam according to claim 1 or 2, having a resilience of 50% or more at 25°C measured in accordance with JIS K7312, and a tan δ of 0.10 or less at a frequency of 10 Hz and 25°C.

4. 4. The polyurethane foam according to claim 1, wherein the core density is 100 to 800 g / L and the rebound resilience at 25°C measured in accordance with JIS K7312 is 60% or more.

5. 5. The polyurethane foam according to claim 1, having an average cell diameter of 50 to 150 μm and a closed cell structure of 50% or more.

6. A polyurethane that is a reaction product of at least a polyol and a polyisocyanate, The polyol contains a polyether polyol (A) containing an oxyethylene group and an oxypropylene group, The polyurethane foam according to any one of claims 1 to 5, wherein the polyether polyol (A) is a bifunctional polyether polyol, which is an adduct of propylene oxide and ethylene oxide to a bifunctional polyoxypropylene glycol, and has an unsaturation degree of 0.010 meq / g or less.

7. 7. The polyurethane foam according to claim 6, wherein the weight ratio of oxyethylene groups to oxypropylene groups in the polyether polyol (A) is in the range of 1:99 to 49:51, the ratio of primary hydroxyl groups is 40 to 99%, and the number average molecular weight calculated from the hydroxyl value is in the range of 1,500 to 15,000.

8. 8. The polyurethane foam according to claim 6, wherein the polyisocyanate is a modified isocyanate.

9. A shoe sole made of the polyurethane foam according to any one of claims 1 to 8.

10. A shoe sole comprising an outsole, an insole and a midsole, wherein the midsole is a molded product of the polyurethane foam according to any one of claims 1 to 8.

11. A shoe sole comprising an outsole, an insole and a midsole, wherein the insole is a molded product of the polyurethane foam according to any one of claims 1 to 8.

12. A sports shoe comprising the shoe sole according to any one of claims 9 to 11.

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